JP4293026B2 - Method for producing ink jet recording material - Google Patents

Description

  The present invention provides a method for producing an ink jet recording material that has excellent ink absorbability so that high-speed recording is possible, dots are perfect circles, image density and gloss are high, and image uniformity is extremely excellent with respect to dyes and pigments. It is about.

  The ink jet recording method that ejects water-based ink from a fine nozzle toward the ink jet recording body to form an image on the surface of the ink jet recording body has low noise during recording, easy formation of a full color image, high speed It is widely used in terminal printers, facsimiles, plotters, form printing, and the like due to the fact that recording is possible and the recording cost is lower than other printing apparatuses.

  In recent years, due to the rapid spread of printers and higher definition and higher speed, inkjet recording media are required to have higher ink absorption speeds than before. Furthermore, with the advent of digital cameras, it is comparable to silver salt photography. There is a strong demand for image uniformity. Further, in order to bring the quality of a recorded image closer to that of a photographic image, further improvement in image recording density and glossiness is desired.

On the other hand, improvement of the ink itself has also been proposed in order to realize image storability similar to that of silver salt photographs, and a water-based dye ink (hereinafter referred to as dye ink) using a highly hydrophilic colorant, which has been the mainstream in the past, has been proposed. In addition, an ink in which a hydrophobic coloring pigment is dispersed (hereinafter referred to as “pigment ink”), which has excellent water resistance and light resistance, is also being widely used.
Colored pigments in pigment inks tend to stay on the coated surface, and the high gloss ink jet recording materials for dye inks that have been used so far have poor fixability and scratch resistance of pigment inks. There is a strong demand for recording media capable of printing with high quality ink.

  To achieve this, a fine pigment is used in the ink receiving layer, and the peak in the pore diameter distribution curve of the coating layer is approximately 0.1 μm or less. In other words, the roundness of the dots is reproduced by controlling the cracks in the coating film. However, a technique for obtaining a higher ink absorption speed and gloss is essential.

For example, in JP-A-11-115308 (see Patent Document 1) and JP-A-2001-246832 (see Patent Document 2), inorganic pigment fine particles having an average primary particle diameter of 20 nm or less in an ink recording layer and polyvinyl alcohol in a binder. An ink jet recording sheet configured to include the above has been proposed. This is due to the cross-linking reaction between borax or boric acid and polyvinyl alcohol. Can be granted. As a result, the roundness of the dots can be reproduced and excellent image quality can be obtained with dye inks. However, the surface gloss is insufficient because the surface layer of the recording sheet is formed of fine pigment and polyvinyl alcohol. Also, the pigment ink has not yet had sufficient ink absorptivity.
In Japanese Patent Application Laid-Open No. 2001-246832 (see Patent Document 2), boric acid or a boron compound is applied on the support between the support and the ink recording layer in an amount of 0.1 g / m ² or more per one surface of the support. The polyvinyl alcohol in the recording layer is cross-linked by boric acid or boron compound in the undercoat, and the coating gels before the recording layer becomes a reduced rate drying part, thereby suppressing cracking of the coating film. . However, the surface gloss of the recording material obtained by this method is not yet satisfactory.

  In JP-A-2000-301828 (see Patent Document 3), a second porous layer is applied to a non-water-absorbing support after applying and drying the first porous layer or before the end of drying. Ink jet recording sheets that do not generate bubbles on the film surface have been proposed. By this method, an ink recording layer free from bubbles and cracks can be obtained, but gloss and ink absorption speed are still insufficient.

Japanese Patent Application Laid-Open No. 5-104848 (refer to Patent Document 4) and Japanese Patent Publication No. 7-37175 (refer to Patent Document 5) describe a method of manufacturing an ink jet recording paper using a water-absorbing base paper as a support. . In JP-A-5-104848, a borax or boric acid treatment layer and an ink receiving layer are sequentially provided on the glossy surface of a glossy paper, but wet silica having an average particle diameter of 1 μm or more is formed on the ink receiving layer. As a result, the gloss and image density were not improved.
The Kokoku 7-37175 Patent Publication, borax or boric acid to one of the coated surface of the base paper obtained by coating per side 0.1 g / ^{m 2} or more and the base paper 5 to 20 g / ^{m 2} Ink Although the ink jet recording material is provided with a receiving layer, high gloss and image density cannot be obtained because wet silica having an average particle diameter of 1 μm or more is used for the ink receiving layer.

  Japanese Patent No. 3322980 (see Patent Document 6) proposes a method for producing a fabric for an ink jet printer by applying boric acid sol containing polyvinyl alcohol after boric acid or borate is supported on the fabric. This is a method for producing a fabric in which a cotton fabric is impregnated with a sodium orthoborate aqueous solution and dried and then coated with boehmite sol, and a high-definition image can be obtained with an inkjet printer.

  In addition, as a technique for imparting gloss, JP-A-7-101142 (see Patent Document 7) provides a glossy expression layer containing colloidal particles and a polymer latex on a recording layer containing a micron order pigment as a main component. There was an attempt. With such a configuration, a certain level of gloss can be obtained, but since the dye in the ink is fixed to the recording layer of the micron order, the image density is low and the uniformity of the image is also inferior. Further, since the peak in the pore distribution curve of the glossy layer is larger than 0.1 μm, that is, the glossy layer is cracked, there is a problem that the visual gloss is low and the fixability of the pigment ink is also poor.

  In order to further increase the gloss, Japanese Patent Application Laid-Open No. 7-117335 (see Patent Document 8) has proposed a method in which the gloss developing layer is pressed against a heated mirror drum while it is wet and the mirror surface is copied. Although a certain level of gloss can be obtained by this method, since the glossy layer has cracks, the uniformity of the image is inferior, and the image density and suitability of the pigment ink cannot be solved.

  Japanese Patent Laid-Open No. 2001-10220 (see Patent Document 9) discloses that the outermost layer using an aggregate pigment having an average particle diameter of 1 μm or less provided with two or more recording layers on a substrate is in a wet state. There has been an attempt to solve problems such as gloss, image density, ink absorbency, etc. by press-bonding to a heated mirror drum and casting. However, the peak in the pore diameter distribution curve of the outermost layer is not less than 0.1 μm or less, that is, the crack of the outermost layer is not controlled, so the dots after printing lack roundness and the image density is insufficient However, the uniformity of the image was also low. In addition, with recent high-definition and high-speed printers, ink absorptivity is insufficient, and when pigment ink is used, a lot of colored pigment is absorbed in the cracked part of the coating film, resulting in unevenness in the image. It was unsuitable.

JP 11-115308 A (pages 3 to 6) JP 2001-246832 A (pages 3 to 6) JP 2000-301828 (pages 5-6) JP-A-5-104848 (pages 2 and 3) Japanese Patent Publication No. 7-37175 (pages 2 and 3) Japanese Patent No. 3322980 (2nd page) JP-A-7-101142 (4th and 9th to 10th pages) JP-A-7-117335 (page 4) JP 2001-10220 A (3rd and 9th to 10th pages)

  The present invention solves the above problems, uses a paper base material that is a gas-permeable base material as a support, has high glossiness and image density, and has sufficient ink absorbability for both dyes and pigments, and It is an object to provide a method for producing an ink jet recording material in which dots are perfectly circular and image uniformity is extremely good.

As a result of intensive studies to solve the above problems, the present inventors can achieve this by a method of forming a specific recording layer on a gas-permeable substrate and forming a specific outermost layer thereon. And found the present invention.
(1) In the method for producing an ink jet recording material in which a recording layer and an outermost layer are provided on a substrate, the substrate has an air permeability (JIS-P-8117) of 30 to 500 sec , and the recording layer has an average particle size of 0. A coating solution for recording layer containing a fine pigment of 0.01 to 1 μm and a hydrophilic binder is applied to one side of the substrate and dried, and at the same time as the application or at the time of drying, the coating solution is dried at a reduced rate. Before reaching the speed, it is formed by thickening or gelling the applied coating liquid, the outermost layer is on the recording layer after the recording layer comes to show a reduced drying speed, The outermost layer coating solution containing fine pigment having an average particle size of 0.01 to 1 μm is applied, and while the outermost layer is in a wet state, it is pressed against a heated mirror drum and dried and peeled off. A method for producing an ink jet recording material, characterized in that it is formed (first invention) Also called).

(2) In the method for producing an ink jet recording material in which a recording layer and an outermost layer are provided on a base material , the air permeability (JIS-P-8117) of the base material is 30 to 500 sec , and the hydrophilic binder used for the recording layer And a coating solution having a crosslinking agent capable of crosslinking reaction is applied to one side of the substrate, and the coating solution is dried or without drying, with an average particle diameter of 0.01 to 1 μm on the coated surface. A recording layer coating solution containing a fine pigment and a hydrophilic binder is applied and dried, and after the recording layer shows a reduced rate of drying, an average particle size of 0.01 to 1 μm is formed on the recording layer. An ink jet recording material comprising: a coating liquid for an outermost layer containing a fine pigment, and press-bonding to a heated mirror drum and drying and peeling while the outermost layer is in a wet state. (Also referred to as the second invention).
(3) One side of the substrate is impregnated or coated with 0.01 to 1.5 g / m ² of boron compound, and the recording layer contains a polymer capable of crosslinking reaction with the boron compound (1) or (2) A method for producing an ink jet recording material according to (2).
(4) Polymers that can be cross-linked by a boron compound are polyvinyl alcohol, cation-modified polyvinyl alcohol, silyl-modified polyvinyl alcohol, polyvinyl acetal, methylcellulose, ethylcellulose, hydroxyethylcellulose, casein, soy protein, synthetic proteins, starch, and polypropylene oxide. , Polyethylene glycol, polyvinyl ether, polyvinyl acrylamide, polyvinyl pyrrolidone, styrene-butadiene copolymer, methyl methacrylate, and styrene-vinyl acetate copolymer. Is the method.
(5) A thermosensitive polymer compound in which the hydrophilic binder contained in the recording layer coating liquid exhibits hydrophobicity at a temperature higher than the temperature sensitive point and reversibly hydrophilic at a temperature lower than the temperature sensitive point. (1) The method for producing an ink jet recording material according to (1), wherein after the recording layer coating liquid is applied, the viscosity is increased or gelled by cooling to a temperature not higher than the temperature sensitive point.

(6) The method for producing an ink jet recording material according to any one of (1) to (5), wherein the air-permeable substrate has a water absorption (JIS-P-8140) of 60 seconds by a Cobb method of 10 to 120 g / m ^2. .
(7) The ink jet recording according to any one of (1) to (6), wherein the peak in the pore diameter distribution curve of the recording layer and the outermost layer is approximately 0.001 to 0.2 μm. It is a manufacturing method of a body.

(8) Wet method silica colloid, alumina oxide, and alumina hydrate produced by condensing gas phase method silica, mesoporous silica, and active silicic acid as the fine pigment contained in the recording layer coating liquid The method for producing an ink jet recording material according to any one of (1) to (7), comprising at least one selected from the group consisting of:
(9) The fine pigment contained in the recording layer coating liquid is at least one silica fine pigment selected from colloidal substances of wet-process silica produced by condensing vapor-phase process silica, mesoporous silica, and active silicic acid. Is a silica-cationic compound aggregate particle treated with a cationic compound. (8) The method for producing an ink jet recording material according to (8).

(10) The fine pigment contained in the outermost layer coating solution is a colloidal product of wet-process silica produced by condensing vapor-phase process silica, mesoporous silica, and active silicic acid, colloidal silica, alumina oxide, and alumina It is at least 1 sort (s) chosen from hydrate, It is a manufacturing method of the inkjet recording body as described in any one of (1)-(9) characterized by the above-mentioned.
(11) The fine pigment contained in the outermost layer coating solution is at least one selected from gas phase method silica, mesoporous silica, colloidal material of wet method silica produced by condensing activated silicic acid, and colloidal silica. The method for producing an ink jet recording material according to (10), wherein the silica fine particle pigment is silica-cationic compound aggregate particles obtained by treating a silica fine pigment with a cationic compound.
(12) The method for producing an ink jet recording material according to (10), wherein the fine pigment contained in the outermost layer coating liquid is alumina oxide.
(13) The average particle size of the fine pigment contained in the outermost layer coating solution is smaller than the average particle size of the fine pigment contained in the recording layer coating solution. It is a manufacturing method of the inkjet recording body as described.

(14) Any one of (1) to (13), wherein a laminate layer containing a polyolefin resin is provided after the outermost layer is formed on the surface having no recording layer and outermost layer of the substrate. The manufacturing method of the inkjet recording body as described in 1 ..
(15) The method for producing an ink jet recording material according to any one of (1) to (14), wherein the outermost layer coating liquid and the recording layer coating liquid are applied online.
(16) The method for producing an ink jet recording material according to any one of (1) to (15), wherein the recording layer coating liquid is applied by a pre-measuring method.

(17) The method for producing an ink jet recording material according to any one of (1) to (16), wherein the coating amount of the recording layer is 3 to 60 times the coating amount of the outermost layer. It is.

(18) Any one of (1) to (17), wherein the haze value (JIS K 7105) of the outermost layer is 30% or less and the sum of the haze values of the outermost layer and the recording layer is 50% or less. The method for producing an ink jet recording material according to any one of the above.
(19) The substrate tension (JIS-P-8118) is 0.8 to 1.1 g / m ² and the thickness is 160 to 270 μm. (1) to (18) It is a manufacturing method of the inkjet recording body as described in any one.

(20) In a method for producing an ink jet recording material in which a recording layer and an outermost layer are provided on a substrate, a step of supplying a substrate having a continuous air permeability (JIS-P-8117) of 30 to 500 sec , a fine pigment, A step of applying a recording layer coating liquid containing a hydrophilic binder, a step of thickening or gelating the recording layer coating liquid, a step of drying the recording layer coating liquid until it exhibits a reduced rate drying rate, Coating having a step of applying a coating liquid for the outermost layer containing a fine pigment on the formed recording layer, and a step of pressing and drying and peeling off a heated mirror drum while the outermost layer is in a wet state This is a method for manufacturing an ink jet recording body manufactured using an apparatus (also referred to as a third invention).

(21) An ink jet recording material produced by the method for producing an ink jet recording material according to any one of (1) to (20).
(22) In the production of an ink jet recording material in which a recording layer and an outermost layer are provided on a substrate, a step of supplying a continuous substrate and a step of applying a recording layer coating liquid containing a fine pigment and a hydrophilic binder A step of thickening or gelating the recording layer coating liquid, a step of drying the recording layer coating liquid until it exhibits a reduced rate of drying, and an outermost layer containing a fine pigment on the formed recording layer It is an apparatus for manufacturing an ink jet recording body, which includes a step of applying a coating liquid and a step of pressure-bonding to a heated mirror drum while the outermost layer is in a wet state.

  The ink jet recording body obtained by the method of the present invention has good ink absorbability so that high-speed recording is possible, the dots are perfect circles, the image density and gloss are high, and the dye ink and pigment with extremely good image uniformity Both inks are excellent.

"Base material"
The present invention uses a gas-permeable substrate for pressurizing and drying a heated mirror drum while the outermost layer is in a wet state for the purpose of increasing the surface gloss of the ink jet recording medium. The gas permeable substrate is not particularly limited as long as it is a gas permeable substrate, and a paper substrate such as acid paper used for general coated paper or neutral paper is used as appropriate. The In addition, resin sheets and nonwoven fabrics having air permeability can be used.

The paper base is composed mainly of wood pulp and a filler containing it as necessary.
As the wood pulp, various chemical pulps, mechanical pulps, regenerated pulps and the like can be used, and these pulps can be beaten by a beating machine in order to adjust paper strength, papermaking suitability, and the like. The beating degree (freeness) of the pulp is not particularly limited, but is generally about 250 to 550 ml (CSF: JIS-P-8121). In order to improve smoothness, it is desirable to advance the beating degree. However, when recorded on paper, paper blur and recording image bleeding caused by moisture in the ink often gives better results if the beating is not advanced. . Accordingly, the freeness is preferably about 300 to 500 ml.

The filler is blended for the purpose of imparting opacity or adjusting the ink absorbability, and calcium carbonate, calcined kaolin, silica, titanium oxide and the like can be used. Especially calcium carbonate becomes a high whiteness substrate, since gloss ink jet recording material is enhanced preferable. The content (ash content) of the filler in the paper substrate is preferably about 1 to 20%, and if it is too much, the paper strength may be reduced. If the amount is too small, the air permeability of the paper base material is deteriorated. Therefore, the preferable filler content is 7 to 20%. Within this range, the smoothness, air permeability, and paper strength are balanced, and as a result, an ink jet recording body with excellent glossiness can be easily obtained.

A sizing agent, a fixing agent, a paper strength enhancer, a cationizing agent, a yield improving agent, a dye, a fluorescent brightening agent, and the like can be added to the paper base as an auxiliary agent. Furthermore, in the size press process of the paper machine, starch, polyvinyl alcohol, cationic resin and the like can be applied and impregnated to adjust the surface strength, sizing degree, and the like. The Steecht sizing degree (as 100 g / m ² paper) is preferably about 1 to 200 seconds. If the sizing degree is low, there may be operational problems such as wrinkling at the time of coating, and if it is high, the ink absorbability may be lowered, and curling and cockling after printing may be remarkable. A more preferred range of sizing is 4 to 120 seconds. Although the basic weight of a base material is not specifically limited, It is about 20-400 g / m < ² >.
For example, paper such as high-quality paper, art paper, coated paper, cast coated paper, craft paper, baryta paper, impregnated paper, vapor-deposited paper, and water-soluble paper is used as appropriate.

The air permeability of the permeable base material (JIS-P-8117), is 30～500Sec. More preferably, it is 35 to 300 sec. Incidentally, when the air permeability is lower than 30 sec, the surface of the obtained ink jet recording body is greatly blurred, and the glossiness of appearance tends to be inferior. On the other hand, if it is longer than 500 sec, the adhesion to the drum is deteriorated at the time of pressure bonding to the mirror drum, and the outermost layer cannot be sufficiently dried, so that it tends to be difficult to obtain a high surface gloss.

  The air-permeable substrate is used to quickly absorb the solvent of the ink-jet ink component of the recording layer, to improve the adhesion between the substrate and the recording layer, or to adjust the hue of the obtained recording medium. An undercoat layer may be provided for the purpose. In addition, in this invention, when it has an undercoat layer, it is called a gas-permeable base material including an undercoat layer. The undercoat layer is a coating layer containing a pigment, an adhesive, and various auxiliary agents.

  The pigment in the undercoat layer is kaolin, clay, calcined clay, amorphous silica (also called amorphous silica), synthetic amorphous silica, zinc oxide, aluminum oxide, aluminum hydroxide, calcium carbonate, satin white, aluminum silicate , Alumina, colloidal silica, zeolite, synthetic zeolite, sepiolite, smectite, synthetic smectite, magnesium silicate, magnesium carbonate, magnesium oxide, diatomaceous earth, styrene plastic pigment, hydrotalcite, urea resin plastic pigment, benzoguanamine plastic pigment, etc. One or more of various publicly known pigments in the general coated paper manufacturing field can be used in combination. Among these, it is preferable to contain amorphous silica, alumina, and zeolite having high ink absorbability as main components.

The average particle size of these pigments (in the case of an aggregated pigment, the aggregated particle size) is preferably about 1 to 10 μm, more preferably 2 to 10 μm. If it is less than 1 μm, the effect of improving the ink absorption rate is poor, and if it exceeds 10 μm, the smoothness after the recording layer is provided is insufficient, and the recording layer may be cracked. Different average particle sizes can be used in combination.
In addition, a pigment with a small average particle diameter can be mix | blended as a subcomponent in order to adjust ink absorptivity or to control permeation of the coating liquid applied on the undercoat layer. Examples of such pigments include colloidal silica and alumina sol.

  As the adhesive for the undercoat layer, polyvinyls including proteins such as casein, soy protein, synthetic protein, various starches such as starch and oxidized starch, polyvinyl alcohol, cationic polyvinyl alcohol, modified polyvinyl alcohol such as silyl modified polyvinyl alcohol Vinyls such as alcohols, cellulose derivatives such as carboxymethyl cellulose and methyl cellulose, styrene-butadiene copolymers, conjugated diene polymer latex of methyl methacrylate-butadiene copolymer, acrylic polymer latex, ethylene-vinyl acetate copolymer Conventionally known adhesives generally used for coated paper, such as a polymer latex, are used alone or in combination.

  Although the blending ratio of the pigment and the adhesive depends on the kind thereof, it is generally adjusted in the range of 1 to 100 parts by weight, preferably 2 to 50 parts by weight with respect to 100 parts by weight of the pigment. In addition, various auxiliary agents such as dispersants, thickeners, antifoaming agents, antistatic agents, preservatives and the like used in the production of general coated paper are appropriately added. In the undercoat layer, a fluorescent dye, a colorant, a white pigment, and the like can be added.

  As a method for forming the undercoat layer, a coating liquid containing the above components may be applied by a known coating method. For example, by various known coating devices such as blade coaters, air knife coaters, roll coaters, bar coaters, gravure coaters, rod blade coaters, lip coaters, curtain coaters, slide beads, slide hoppers, and die coaters such as slot dies. It is good to apply.

The tightness (JIS-P-8118) of the air-permeable substrate used in the present invention is more preferably 0.8 to 1.1 g / m ² . If the tension is less than 0.8 g / m ² , the surface roughness of the obtained ink jet recording material will increase, and if it is greater than 1.1 g / m ² , sticking to the drum will occur when crimping to the mirror drum. This is not preferable because it becomes worse and it is difficult to obtain high gloss.
Further, the thickness of the substrate is more preferably 160 to 270 μm. If the thickness is less than 160 μm, the unevenness of the surface of the obtained ink jet recording material will be large, and if it is more than 270 μm, sticking to the drum will be poor when it is pressed to the mirror drum, and it will be difficult to obtain high gloss. Therefore, it is not preferable.

Further, as a means for thickening or gelling the recording layer coating liquid described later, when a gas-permeable substrate is impregnated with a solution of a crosslinking agent (for example, a boron compound) in advance, a cobbing method for the gas-permeable substrate. The water absorption at 60 seconds is preferably 10 to 120 g / m ² , more preferably 15 to 100 g / m ² . When the water absorption of the substrate is less than 10 g / m ² , the boron compound solution is not sufficiently absorbed by the substrate, and when it is more than 120 g / m ² , the surface of the obtained ink jet recording material has a large surface irregularity after printing. Is not preferred because cockling occurs and glossiness is poor.

"Formation of recording layer"
In the present invention, a recording layer is formed on the gas-permeable substrate. The recording layer is a layer formed for the purpose of absorbing and fixing a dye or a solvent component in ink that cannot pass through or absorb the outermost layer. Therefore, a balance between the ink absorption speed and the ink absorption capacity is required. Further, in order to improve the glossiness of the outermost layer, the recording layer is required to have smoothness and film formability, but excessive film formation impairs ink absorbability.

The recording layer of the present invention is coated and dried with a recording layer coating solution containing a fine pigment having an average particle size of 0.01 to 1 μm and a hydrophilic binder, and the coated layer is in the middle of drying. And before the recording layer becomes a reduced rate drying part (indicating a reduced rate drying rate), it is thickened or gelled (for example, the coating liquid is thickened or gelled by a crosslinking agent such as a boron compound). Form.
This is considered to have a great effect of preventing the coating layer from cracking due to hot air during drying by thickening or gelling the coating in the early stage of drying and preventing the coating from penetrating into the substrate.

  Examples of fine pigments having an average particle size of 0.01 to 1 μm include gas phase method silica, mesoporous silica, wet method silica colloid produced by condensation of activated silicic acid, alumina oxide, and alumina hydrate. It is preferable to use at least one selected from Among these, gas phase method silica and alumina oxide are preferably selected. Among the alumina oxides, gas phase method (fumed) alumina oxide is preferable.

  As for the form of the fine pigment, an aggregated particle dispersion of the pigment is mainly preferably used for the purpose of obtaining high ink absorbability, coating film forming property and smoothness. The average particle size needs to be 0.01 to 1 μm. From the viewpoint of the ink absorption rate and the like, an aggregate pigment having an average particle diameter of 0.01 to 0.7 μm formed by aggregating primary particles having an average primary particle diameter of 0.003 to 0.040 μm is more preferable. Average particles formed by agglomeration of primary particles having an average primary particle size of 0.005 to 0.020 μm in order to easily fix dyes and pigments in the ink and to obtain a high ink absorption rate, printing density, and gloss. A pigment having a diameter of 0.5 μm or less is more preferable.

  A pigment having an average particle size of 0.7 μm or less can be obtained by, for example, a strong force by mechanical means, that is, a so-called breaking down method (a method of fragmenting a bulk material). Mechanical means include: ultrasonic homogenizer, pressure homogenizer, liquid collision homogenizer, high-speed rotary mill, roller mill, container drive medium mill, medium agitator mill, jet mill, mortar, disintegrator (covered in a bowl-shaped container) A device for grinding and kneading the pulverized material with a bowl-shaped stirring bar), a sand grinder, and the like. In order to reduce the particle size, classification and repeated pulverization can be performed.

  The average particle diameter referred to in the present invention is, regardless of whether the pigment is powder or slurry, first, 200 g of a 3% pigment aqueous dispersion is prepared, and then stirred and dispersed at 1000 rpm for 30 minutes with a commercially available homomixer. Immediately observed with an electron microscope (SEM and TEM) (taken 10,000-400,000 times electron micrographs, measured and averaged the diameter of a 5 cm square particle, “Particle Handbook”, Asakura Bookstore, p52, 1991). As a result of measurement by the present inventors, when the pigment is powder (most pigments having a particle diameter of 1 μm or more), it almost matches the manufacturer's catalog value, but in the case of slurry (most pigments having a particle diameter of 1 μm or less). Although the particle size varies greatly depending on the state of aggregation of the slurry, almost the same value can be obtained under the above measurement conditions.

  Vapor phase silica preferably used is also called fumed silica and is generally made by flame hydrolysis. Specifically, a method of making silicon tetrachloride by burning with hydrogen and oxygen is generally known, but silanes such as methyltrichlorosilane and trichlorosilane can be used alone or silicon tetrachloride instead of silicon tetrachloride. Can be used in a mixed state.

Mesoporous silica is a porous silica material having an average pore diameter of 1.5 to 100 nm. In addition, mesoporous silica into which aluminum, titanium, vanadium, boron, manganese atoms or the like are introduced can also be used. The physical properties of the porous body are not particularly limited, but the BET specific surface area (nitrogen adsorption specific surface area) is preferably 200 to 1500 m ² / g, and the pore volume is preferably 0.5 to 4 cc / g. The method for synthesizing mesoporous silica is not particularly limited, but is described in U.S. Pat. No. 3,556,725, in which a quaternary ammonium salt containing a long-chain alkyl is used as a template. Hydrothermal synthesis method using amorphous silica powder or alkaline silicate aqueous solution described in Table 5-5503499 etc. as a silica source and using a quaternary ammonium salt having a long chain alkyl group or a phosphonium salt as a template, A method of synthesizing a layered silicate such as kanemite as a silica source described in Kaihei 4-238810, etc. by an ion exchange method using a long-chain alkylammonium cation as a template, further dodecylamine, hexadecylamine, etc. Amines, nonionic surfactants, etc. As the template, it is as a source of silica and water glass or the like and a method of synthesis using an active silica obtained by ion exchange. Examples of the method for removing the template from the nanoporous silica precursor include a method of baking at a high temperature and a method of extracting with an organic solvent.

  The wet-process silica colloid produced by condensing activated silicic acid is at least selected from an aqueous solution of active silicic acid and alkoxysilane after adding alkali to the colloidally dispersed silica seed solution. It is a secondary silica dispersion obtained by growing silica fine particles by adding one kind of feed solution little by little, and can be obtained by a method described in, for example, JP-A-2001-354408.

  Alumina oxide is also generally called crystalline alumina oxide having crystallinity. Specific examples include alumina oxide having χ, κ, γ, δ, θ, η, ρ, pseudo γ, and α crystals. In the present invention, gas phase method alumina oxide and alumina oxide having γ, δ, and θ crystals are preferably selected from the viewpoint of gloss and ink absorbability. Vapor phase alumina oxide (fumed alumina) having a sharp particle size distribution and particularly excellent film formability is most preferred.

  Vapor phase alumina oxide is alumina formed by high temperature hydrolysis of gaseous aluminum trichloride, resulting in the formation of high purity alumina particles. The primary particle size of these particles is nano-order, and shows a very narrow particle size distribution (particle size distribution). Such vapor phase alumina oxide has a cationic surface charge. The use of vapor phase alumina oxide in ink jet coating is shown, for example, in US Pat. No. 5,171,626.

  The alumina hydrate is not particularly limited, but boehmite or pseudoboehmite is preferably selected from the viewpoint of ink absorption speed and film formability. The production method of alumina hydrate includes, for example, a method of hydrolyzing aluminum isopropoxide with water (BE Yoldas, Amer. Ceram. Soc. Bull., 54, 289 (1975), etc.) and aluminum alkoxide. And the like (Japanese Patent Laid-Open No. 06-064918).

  The hydrophilic binder contained in the recording layer is a water-soluble binder or water-dispersible binder that thickens or gels at the same time as or after coating the recording layer coating liquid among known binders for inkjet recording. Can be used.

  For example, in the case of thickening or gelling by combining a crosslinking agent, a binder that causes a crosslinking reaction with the crosslinking agent is selectively used. Typical examples of boron compounds having a high crosslinking rate include polyvinyl alcohol, cation-modified polyvinyl alcohol, silyl-modified polyvinyl alcohol, polyvinyl acetal, methylcellulose, ethylcellulose, hydroxyethylcellulose, casein, soy protein, synthetic proteins, starch, polypropylene oxide, polyethylene Examples include glycol, polyvinyl ether, polyvinyl acrylamide, polyvinyl pyrrolidone, styrene-butadiene copolymer, methyl methacrylate, styrene-vinyl acetate copolymer. Among these, polyvinyl alcohol is preferably selected particularly from the viewpoint of adhesion to the pigment. Among these, polyvinyl alcohol having a polymerization degree of 2000 or more is preferable from the balance between film formability and ink absorbability, and polyvinyl alcohol having a polymerization degree of 3600 to 5000 is more preferable. In addition, two or more binders (for example, a water-soluble resin and a water-soluble resin, a water-soluble resin and a latex, etc.) may be used in combination in order to improve ink absorbability.

The recording layer preferably contains a cationic compound. Examples of the cationic compound include 1) polyalkylene polyamines such as polyethylene amine and polypropylene polyamine, or derivatives thereof, 2) acrylic resins having secondary amine groups, tertiary amine groups, and quaternary ammonium groups, 3) Polyvinylamine, polyvinylamidine, 5-membered ring amidines, 4) Dicyan cationic resin represented by dicyandiamide-formalin polycondensate, 5) Polyamine cationic resin represented by dicyandiamide-diethylenetriamine polycondensate, 6) Epo chlorohydrin - dimethylamine addition polymers, 7) dimethyldiallylammonium chloride -SO ₂ copolymer, 8) diallylamine -SO ₂ copolymer, 9) dimethyldiallylammonium chloride polymer, 10) vinylbenzyl triallyl A Homo salt homopolymer or copolymer, 11) allylamine salt polymer, 12) dialkylaminoethyl (meth) acrylate quaternary salt polymer, 13) acrylamide-diallylamine salt copolymer, 14) polyaluminum chloride, Examples of the commercially available products include aluminum salts such as polyaluminum acetate and polyaluminum lactate. In addition, as addition amount of a cationic compound, 1-30 mass parts is preferable with respect to 100 mass parts of pigments, and 2-15 mass parts is more preferable.

  When a silica-based pigment is used, the silica-cationic compound aggregate particles obtained by mixing and aggregating silica and a cationic compound are 0.01 to 1 μm, preferably 0.01 to 0.7 μm. Preference is given to fine particles of pulverized silica-cationic compound aggregates. In this case, the cationic compound is appropriately selected from the above cationic compounds. In particular, aluminum salts such as 1) 5-membered ring amidines, 2) polyaluminum chloride, polyaluminum acetate, and polyaluminum lactate are preferred because of the fixability and dispersibility of dyes and pigments in the ink.

  The recording layer coating solution for forming the recording layer is prepared as an aqueous coating solution using water containing the above pigment, a hydrophilic binder, and, if necessary, a cationic compound as a solvent. The ratio of the pigment and the hydrophilic binder is preferably in the range of 100/50 to 100/2 by mass ratio. 100 / 30-100 / 5 is preferable from the balance of ink absorptivity and coating film strength, and 100 / 25-100 / 10 is more preferable. In addition to pigments, hydrophilic binders, and cationic compounds used in combination as needed, the recording layer contains dispersants, thickeners, antifoaming agents, colorants, and antistatic agents used in general coated paper production. Various auxiliary agents such as preservatives and preservatives are appropriately added.

The coating amount of the recording layer coating liquid is not particularly limited, but is about 1 to 40 g / m ² , preferably 5 to 30 g / m ² . If the coating amount is small, the recent high-speed and high-speed printer may have insufficient ink absorption speed, and if it is too large, it is difficult to control cracks in the coating film.
From the balance between the ink absorption speed and the ink absorption capacity, the coating amount of the recording layer is preferably at least three times the outermost layer coating amount described later. 7 times or more is more preferable, and 10 to 60 times is the most preferable range.

  As a coating apparatus for applying the recording layer coating liquid, a pre-weighing method is preferred from the viewpoint of the physical properties of the paint and the coating amount. Examples of the pre-measuring method include various known methods such as lip coaters, curtain coaters, slide beads, slide hoppers, and die coaters such as slot dies. Moreover, when applying two or more layers, it is preferable to apply by Wet on Wet (method to apply the upper layer on the lower layer while the lower layer is not dried).

  Although it is dried after coating, the drying method is not particularly limited. A drying device conventionally used in a coating machine can be used.For example, various heating drying methods such as hot air drying, gas heater drying, high-frequency drying, electric heater drying, infrared heater drying, and laser drying are preferable and used as appropriate. The Of these, hot air drying is preferred because it is advantageous in terms of cost.

In the first aspect of the present invention, it is necessary to thicken or gel the coated recording layer coating solution simultaneously with coating, or after coating and drying, and before the drying reaches a reduced rate of drying. There is.
Generally, the drying process of the applied coating liquid is classified into a constant rate drying part in the initial stage of drying, a subsequent reduction rate drying part, and a drying end point. Here, the constant rate drying part is a drying region that decreases in proportion to time if the moisture content in the coating layer is a constant drying condition. The surface temperature of the coating layer is almost constant because it evaporates while being removed. Although depending on the drying method and the temperature of the paint at the time of coating, in the case of hot air drying at 100 ° C. or higher, the surface temperature in the constant rate drying section is 20 to 45 ° C.
On the other hand, the rate-decreasing drying part is a drying area when the water content in the coating layer is less than the void volume of the coating layer, and in this area the water that interacts is evaporated. Therefore, the surface temperature of the coating layer rises. When this reduction drying is completed, the temperature of the drying hot air and the surface temperature of the coating layer coincide with each other, and this is the drying end point.

  In the first invention, after the recording layer is applied, the coating is thickened or gelled at the same time as coating or during the drying of the formed recording layer and before the recording layer becomes a decrement drying part, that is, constant. It is a rate drying area. This is because the coating is thickened or gelled in the early stages of drying to prevent cracks in the coating layer due to hot air during drying, and also to prevent the coating from penetrating into the substrate. .

A method for thickening or gelling the applied coating liquid is not particularly limited.
For example, (a) thickening or gelation by using a crosslinking agent capable of crosslinking reaction with a hydrophilic binder blended in the recording layer, (b) thickening or gelling by supplying energy such as electron beam Examples of the method include (c) a hydrophilic binder, a thermosensitive polymer compound that exhibits hydrophilicity and hydrophobicity depending on temperature conditions, and a method of increasing the viscosity or gelation by changing the temperature.

  (A) As a method of thickening or gelating using a crosslinking agent capable of crosslinking reaction with the hydrophilic binder blended in the recording layer, the exemplified hydrophilic binder and the crosslinking agent capable of crosslinking reaction with the hydrophilic binder. Are used in combination. For example, a substrate is preliminarily coated and impregnated with a cross-linking agent, and a recording layer coating liquid is applied. A cross-linking agent is mixed and applied in a recording layer coating liquid. After applying a recording layer coating liquid, Although it is good to manufacture by the method of apply | coating a crosslinking agent, etc., since a recording layer with uniform viscosity increase or gelation is obtained, it is preferable to apply a crosslinking agent beforehand.

  Examples of the crosslinking agent include a boron compound, an epoxy compound, a glycidyl compound, a zirconium compound, an aluminum compound, a chromium compound, and the like. Among these, a boron compound is particularly preferable because thickening or gelation occurs quickly.

The boron compound is an oxygen acid having a boron atom as a central atom and a salt thereof. Examples include orthoboric acid, metaboric acid, hypoboric acid, tetraboric acid, pentaboric acid, and their sodium, potassium, and ammonium salts. Among these, orthoboric acid and disodium tetraborate are preferably used because they have an effect of moderately thickening the paint.
Although content of a boron compound is based also on the kind of boron compound and a hydrophilic binder, it is preferable to contain 0.01-1.5 g / m < ² > on the single side | surface of a base material. When the amount is more than 1.5 g / m ² , the crosslinking density with the hydrophilic binder increases, the coating film becomes hard and is easily broken. On the other hand, when the amount is less than 0.01 g / m ² , the crosslinking with the hydrophilic binder is weak, the gelation of the paint is weakened, and the coating film is easily cracked.

  (B) As a method of increasing the viscosity or gelation by supplying energy such as an electron beam, the recording layer binder does not have a radical polymerizable unsaturated bond, and the aqueous solution is irradiated with an electron beam. Using a hydrophilic binder that forms a hydrogel by applying a coating liquid containing 1 to 100 parts by weight of the hydrophilic binder with respect to 100 parts by weight of the fine pigment, and then irradiating an electron beam to the coating The recording layer may be formed by hydrogelating the applied coating liquid and then drying to form a recording layer.

  Examples of the hydrophilic binder that does not have a radical polymerizable unsaturated bond and forms a hydrogel by irradiating an aqueous solution with an electron beam include, for example, polyvinyl alcohol, polyethylene oxide, polyalkylene oxide, polyvinyl pyrrolidone, water-soluble Polyvinyl acetal, poly-N-vinylacetamide, polyacrylamide, polyacryloylmorpholine, polyhydroxyalkyl acrylate, polyacrylic acid, hydroxyethylcellulose, methylcellulose, hydroxypropylmethylcellulose, hydroxypropylcellulose, gelatin, casein, and water-soluble derivatives thereof, Moreover, these copolymers etc. can be illustrated and it is good to use these individually or in combination.

  As the electron beam irradiation method, for example, a scanning method, a curtain beam method, a broad beam method, or the like is adopted, and an acceleration voltage at the time of irradiation with an electron beam is appropriately about 50 to 300 kV. The amount of electron beam irradiation is preferably adjusted in the range of about 1 to 200 kGy. If it is less than 1 kGy, it is not sufficient to gel the coating layer, and irradiation exceeding 200 kGy is not preferable because it may cause deterioration or discoloration of the substrate or the coating layer.

  (C) As a hydrophilic binder, a temperature-sensitive polymer compound that exhibits hydrophilicity and hydrophobicity depending on temperature conditions is used. As a method of thickening or gelling by changing the temperature, as the binder, It is preferable to use a temperature-sensitive polymer compound that exhibits hydrophilicity in the temperature range and exhibits hydrophobicity in the temperature range higher than the temperature-sensitive point.

  When this thermosensitive polymer compound is used, coating is performed at a temperature higher than the temperature sensitive point, and by cooling to a temperature lower than the temperature sensitive point, the applied layer is thickened or gelled and then dried. A recording layer may be formed. Examples of such temperature-sensitive polymer compounds include those disclosed in JP-A-2003-40916, which are obtained by polymerization in the presence of polyvinyl alcohol and / or polyvinyl alcohol derivatives. it can.

In particular,
(1) One or more monomers (main monomer (M)) from which a polymer compound exhibiting the temperature responsiveness (hydrophilicity-hydrophobicity change) can be obtained by homopolymerizing polyvinyl alcohol and / or A polymer compound obtained by polymerization in the presence of a polyvinyl alcohol derivative, or (2) a polymer compound can be produced by reacting with the main monomer (M) and exhibits temperature responsiveness by homopolymerization. It is a polymer compound obtained by polymerizing a monomer (submonomer (N)) and a main monomer (M) from which a polymer compound cannot be obtained in the presence of polyvinyl alcohol and / or a polyvinyl alcohol derivative.
By using the submonomer (N) as a copolymerization component, it is possible to obtain polymer compounds having different temperature sensitive points and film formability.
The main monomer (M), submonomer (N), polyvinyl alcohol and polyvinyl alcohol derivative can be used alone or in combination of two or more.

Although the temperature sensitive point of a temperature sensitive high molecular compound is not specifically limited, It is preferable that it is 5-30 degreeC. Incidentally, if the temperature is less than 5 ° C., the cooling efficiency when the recording layer is cooled and then the coating layer is gelled after coating the recording layer coating liquid is deteriorated. When the cooling efficiency is poor, coating liquid will penetrate into the undercoat layer, gelation becomes insufficient, for example, cause the case provided uppermost layer on said layer gloss is lowered. When the temperature exceeds 30 ° C., the recording layer coating solution gels during coating, and tends to be unable to be stably produced. A particularly preferred temperature sensitive point is 10 to 20 ° C.

  The glass transition point of the temperature-sensitive polymer compound is not particularly limited, but the glass transition point is preferably -20 to 100 ° C. from the viewpoint of film forming property, etc., and generally the viewpoint of imparting flexibility to the obtained recording medium. To -20 to 40 ° C is preferred. Incidentally, when the temperature is less than −20 ° C., the ink absorbability is not sufficient. On the other hand, when the temperature exceeds 100 ° C., the film formability becomes insufficient and the coating film strength decreases.

  The thermosensitive polymer compound is preferably used in the form of a polymer emulsion containing the thermosensitive polymer compound. This polymer emulsion has a temperature (temperature sensitive point) at which the viscosity changes suddenly due to the influence of the hydrophilic-hydrophobic change due to the temperature change of the temperature-sensitive polymer compound contained.

Preparation of such a temperature sensitive point and a glass transition point can be adjusted by the blending ratio of the following main monomer (M), submonomer (N), polyvinyl alcohol, or polyvinyl alcohol derivative.
The use ratio of the main monomer (M) and the submonomer (N), polyvinyl alcohol and / or polyvinyl alcohol derivative is determined within a range in which the obtained polymer compound (A) exhibits temperature responsiveness. The content of polyvinyl alcohol or polyvinyl alcohol derivative in A) is not particularly limited within the range of the above conditions, but is 0.1 to 50 wt% from the viewpoint of the water resistance of the coating film of the finally obtained recording medium. Is preferably used, and more preferably 0.5 to 20 wt%.

  The main monomer (M) is an N-alkyl or N-alkylene-substituted (meth) acrylamide derivative (where (meth) acryl is a simple notation of methacryl (or methacryl) or acryl), vinylmethyl Specific examples include N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-cyclopropyl (meth) acrylamide, N-ethyl (meth) acrylamide, N, N-diethyl. Acrylamide, N, N-dimethyl (meth) acrylamide, Nn-propyl (meth) acrylamide, N-methyl-Nn-propylacrylamide, N-methyl-N-isopropylacrylamide, N- (meth) acryloylpyrrolidine, N- (meth) acryloylpiperi N-tetrahydrofurfuryl (meth) acrylamide, N-methoxypropyl (meth) acrylamide, N-ethoxypropyl (meth) acrylamide, N-isopropoxypropyl (meth) acrylamide, N-ethoxyethyl (meth) acrylamide, N -(2,2-Dimethoxyethyl) -N-methylacrylamide, N-methoxyethyl (meth) acrylamide, N- (meth) acryloylmorpholine and the like can be mentioned. From the viewpoint of film formability, N-isopropylacrylamide, Nn-propylacrylamide, N, N-diethylacrylamide, and N-acryloylmorpholine are preferable.

  Examples of the auxiliary monomer (N) include lipophilic vinyl compounds, hydrophilic vinyl compounds, and ionic vinyl compounds. Specifically, lipophilic vinyl compounds include methyl (meth) acrylate, ethyl (meth) acrylate, n -Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl methacrylate, styrene, α-methylstyrene, ethylene, isoprene, butadiene, vinyl acetate, vinyl chloride and the like, and 2-hydroxy is a hydrophilic vinyl compound. Ethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, (meth) acrylamide, N-methyl (meth) acrylamide, N-methylol acrylamide, diacetone acrylamide, methylene bisacrylamide, N, N-dimethyl acrylate Examples include amino group-containing monomers such as noethyl (meth) acrylate and N, N-diethylaminoethyl (meth) acrylate, 2-methyl-5-vinylpyridine, N-vinyl-2-pyrrolidone, N-acryloylpyrrolidine, and acrylonitrile. Examples of ionic vinyl compounds include acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, crotonic acid, butenetricarboxylic acid, monoethyl maleate, monomethyl maleate, monoethyl itaconate, monomethyl itaconate and the like. Examples include acid group-containing monomers, 2-acrylamido-2-methyl-propanesulfonic acid, styrene sulfonic acid, vinyl sulfonic acid, sulfonic acid group-containing monomers such as (meth) acryl sulfonic acid, and the like. In particular, methyl (meth) acrylate, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, styrene, 2-hydroxypropyl (meth) acrylate, acrylamide, methacrylamide, diacetone acrylamide, and methylene bisacrylamide are preferably used. It is done. From the viewpoint of the film formability of the coating layer obtained using the polymer emulsion of the present invention, acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, crotonic acid, butenetricarboxylic acid, monoethyl maleate, Carboxylic acid group-containing monomers such as monomethyl maleate, monoethyl itaconate and monomethyl itaconate, sulfonic acid groups such as 2-acrylamido-2-methyl-propane sulfonic acid, styrene sulfonic acid, vinyl sulfonic acid and (meth) acryl sulfonic acid It is preferable to use an anion group-containing monomer such as a containing monomer, and it is particularly preferable to use a carboxylic acid group-containing monomer such as acrylic acid, methacrylic acid, itaconic acid, fumaric acid, and maleic acid.

In the second aspect of the present invention, a coating liquid having a hydrophilic binder used for the recording layer and a crosslinking agent capable of crosslinking reaction is applied in advance to one surface of the base material on the air-permeable substrate, and the coating liquid is dried. After or without drying, the recording layer coating solution is applied and dried.
In this case, the water absorption for 60 seconds by the Cobb method of the air-permeable base material is preferably 10 to 120 g / m ² , and more preferably 15 to 100 g / m ² . Without water absorbency of the substrate a solution of 10 g / m ² less than the cross-linking agent is sufficiently absorbed by the substrate, also large Bokotsuki of 120 g / m ² greater than the surface of the obtained ink jet recording material, after printing Is not preferred because cockling occurs and glossiness is poor.
As the cross-linking agent, the cross-linking agent can be used as appropriate, and among them, a boron compound is particularly preferable because thickening or gelation occurs quickly. Among boron compounds, orthoboric acid and disodium tetraborate are preferably used because they have an effect of appropriately thickening the paint.

"Formation of the outermost layer"
In the present invention, the outermost layer is formed on the recording layer. At this time, after the recording liquid whose recording layer has been thickened or gelled is dried and exhibits a reduced rate of drying, the outermost layer coating liquid is formed. The outermost layer is formed to obtain surface gloss. Besides this, the dye or pigment in the ink is quickly fixed to obtain high color (high print density) and uniform image (dot roundness). It is a layer for expressing.
In order to obtain the surface gloss, after the recording layer described above exhibits a decreasing rate of drying, an outermost layer coating liquid containing fine pigment having an average particle diameter of 0.01 to 1 μm is formed on the recording layer. It is necessary to form the outermost layer by coating and pressing on a heated mirror drum while in a wet state. This is because the moisture contained in the recording layer after the decreasing rate drying section and the moisture contained in the outermost layer in a wet state are evaporated and dried by being pressed against a heated mirror drum, When the outermost layer is peeled from the drum, an ink jet recording material having the outermost layer excellent in ink absorbability and gloss can be obtained.

  As the fine pigment contained in the outermost layer, for example, the fine pigment disclosed in the recording layer can be used, and a colloidal material of colloidal wet-type silica produced by condensing vapor-phase silica, mesoporous silica, and active silicic acid. At least one selected from silica, alumina oxide, and alumina hydrate is selected. Among these, colloidal silica, gas phase method silica, and alumina oxide are preferable because excellent gloss can be obtained. In particular, gas phase method silica and alumina oxide are preferable because the fixability of the pigment ink is good, and alumina oxide is particularly preferable. Among the alumina oxides, gas phase method (fumed) alumina oxide is preferable. The form of the pigment may be a monodispersion or an aggregated particle dispersion, but the outermost layer may have a monodisperse of the above pigment or an aggregated particle dispersion in order to obtain a high print density and high gloss. Of these, those having a small particle diameter are mainly preferably used.

  The average particle diameter of the pigment needs to be 0.01 to 1 μm. From the viewpoint of the ink absorption rate and the like, an aggregate pigment having an average particle diameter of 0.01 to 0.7 μm formed by aggregating primary particles having an average primary particle diameter of 0.003 to 0.040 μm is more preferable. Average particles formed by agglomeration of primary particles having an average primary particle size of 0.005 to 0.020 μm in order to easily fix dyes and pigments in the ink and to obtain a high ink absorption rate, printing density, and gloss. A pigment having a diameter of 0.5 μm or less is more preferable. Further, in the fine pigment constituting the outermost layer, a pigment having an average particle diameter of 0.01 to 0.2 μm formed by agglomerating primary particles having an average primary particle diameter of 0.007 to 0.013 μm has a higher gloss. In addition, it is more preferable for obtaining color development.

When colloidal silica is used for the outermost layer , it can be applied without containing a binder, but usually a fine pigment and a binder are blended. As the binder, known binders can be used, but it is preferable to incorporate a latex binder in the outermost layer.
The latex binder is not particularly limited. For example, an acrylic resin emulsion, (poly) urethane resin emulsion, styrene resin emulsion, styrene-acrylate copolymer resin emulsion, styrene-butadiene copolymer emulsion , Methyl methacrylate-butadiene copolymer emulsion, acrylic ester and methacrylate ester polymers and copolymer emulsions, vinyl polymer emulsions such as ethylene vinyl acetate copolymer, or the carboxy groups of these various polymers Examples include functional group-modified polymer emulsions with functional group-containing monomers. In particular, an acrylic resin emulsion, a (poly) urethane resin emulsion, and a styrene resin emulsion are preferably selected. The average particle diameter of the emulsion latex is preferably 0.08 [mu] m or less, more preferably in the range of 0.005 to 0.05 [mu] m, based on gloss development and printing density. From the viewpoint of ink fixing properties, the emulsion latex is preferably cationically modified.

To obtain a high gloss, the present invention is pressure mirror drum heated during outermost layer in a wet state After wearing, dried, Utsushitoru the mirror surface of the drum in the outermost layer coating liquid layer, the so-called casting method Is adopted. In order to obtain a more smooth and highly glossy surface, the glass transition temperature of the emulsion latex is preferably 30 ° C. or lower. A more preferable range is −50 ° C. to 10 ° C., and a most preferable range is −35 ° C. to 0 ° C. Of course, other binders (for example, water-soluble resin binders) may be used in combination as long as the quality is not impaired.
The ratio of the fine pigment on the outermost layer and the latex binder is not particularly specified as long as the ink absorbability is not impaired, but the mass ratio is preferably in the range of 100/100 to 100/3, and the ink absorbency and the coating strength. From the balance of 100/30 to 100/10, it is more preferable.

  In the present invention, by using a fine pigment of 0.01 to 1 μm, or by using a fine pigment of 0.01 to 1 μm and a latex binder, it becomes possible to adjust the balance of gloss, printing density and ink absorption speed. By setting the peak in the pore diameter distribution curve to about 0.001 to 0.2 μm or less, that is, in a state where there is no crack in the coating film, it is possible to obtain image uniformity.

The outermost layer of the present invention may contain a cationic compound. Examples of the cationic compound include 1) polyalkylene polyamines such as polyethylene amine and polypropylene polyamine, or derivatives thereof, 2) acrylic resins having secondary amine groups, tertiary amine groups, and quaternary ammonium groups, 3 ) Polyvinylamine, polyvinylamidine, 5-membered ring amidines, 4) Dicyan cation resin represented by dicyandiamide-formalin polycondensate, 5) Polyamine cation resin represented by dicyandiamide-diethylenetriamine polycondensate, 6) Epo chlorohydrin - dimethylamine addition polymers, 7) dimethyldiallylammonium chloride -SO ₂ copolymer, 8) diallylamine -SO ₂ copolymer, 9) dimethyldiallylammonium chloride polymer, 10) vinylbenzyl triallyl en 11) homopolymer or copolymer of nium salt, 11) polymer of allylamine salt, 12) dialkylaminoethyl (meth) acrylate quaternary salt polymer, 13) acrylamide-diallylamine salt copolymer, 14) polyaluminum chloride, Examples of the commercially available products include aluminum salts such as polyaluminum acetate and polyaluminum lactate. In addition, as addition amount of a cationic compound, 1-30 mass parts is preferable with respect to 100 mass parts of pigments, and 2-15 mass parts is more preferable.

  When using a silica-based pigment as the pigment, silica-cationic compound aggregate particles obtained by mixing and aggregating silica and a cationic compound are 0.01 to 1 μm, preferably 0.01 to 0.5 μm, More preferably, the silica-cationic compound aggregate fine particles are ground to 0.01 to 0.2 μm. In this case, the cationic compound is appropriately selected from the cationic compounds described above. In particular, 4) such as 1) 5-membered ring amidines, 2) aluminum salts such as polyaluminum chloride, polyaluminum acetate, and polyaluminum lactate, and 3) diallyldimethylammonium chloride because of the fixability and dispersibility of dyes and pigments in the ink. A quaternary ammonium salt is preferred.

After the coating, the outermost layer is pressure-bonded to the mirror drum, dried by the mirror drum, and the mirror surface is copied onto the coating layer. To easily peeled off the uppermost layer from the mirror surface drum, generally commercially available release agent, for example, stearic acid amide, polyethylene wax, such as ammonium oleate is added as appropriate to the outermost layer coating solution. Among these, a cationic release agent is particularly preferable. Although the addition amount of a mold release agent is not specifically limited, Generally it is 0.5-10 mass parts with respect to 100 mass parts of pigments.

  In addition to the fine pigments, binders, cationic compounds, and release agents, the outermost layer coating solution includes preservability improvers, dispersants, thickeners, antifoaming agents, colorants, antistatic agents, preservatives, etc. The various auxiliaries are appropriately added.

The coating amount of the outermost layer is preferably in the range of 0.1 to 10 g / ^{m 2,} more preferably 0.2-5 g / ^{m 2,} more preferably 0.5 to 2 g / ^{m 2.} If the coating amount is small, the coating film becomes thin and interference colors due to light are likely to be generated. On the other hand, if the coating amount is large, the ink absorption rate may be significantly reduced.

Examples of the coating device for obtaining the outermost layer include a blade coater, an air knife coater, a roll coater, a bar coater, a gravure coater, and a rod blade coater, but a paint pool is formed above the tangent line between the mirror drum and the press roll. After forming the outermost layer and applying the outermost layer, a method of pressure-bonding to a heated mirror drum while in a wet state is preferable because it has a very large effect on gloss improvement.

Further, it is preferable to apply the outermost layer continuously after applying and drying the recording layer with one apparatus. When this method is used, the sheet once coated with the recording layer is not wound, so that the state of the recording layer due to a pressure difference between the portion close to the core and the portion close to the surface is prevented during winding. Therefore, it is possible to form a recording layer and a surface layer that are homogeneous in the production flow direction.

The outermost layer is pressure-bonded to the mirror drum after coating. The so-called casting method, in which the coating liquid is dried with a mirror drum and the mirror surface is copied to the outermost surface, is the most effective and preferable. In this case, considering the crack control and the drying efficiency of the outermost layer, the surface temperature of the heated mirror drum is preferably in the range of 80 to 120 ° C.
In the casting method, if the outermost layer is insufficiently dried after being crimped to the mirror drum, it may be dried in a subsequent process, and when crimped to the mirror drum and dried, from the back surface, by infrared rays, etc. It is also possible to assist in drying. Further, in order to correct the curl of the obtained recording material, a humidity control area may be provided after drying. The drying method for the post-process is not particularly limited, and various conventionally known drying methods such as hot air drying, gas heater drying, high-frequency drying, electric heater drying, infrared heater drying, laser drying, and electron beam drying can be used. Used as appropriate. Of these, hot air drying is preferred because it is advantageous in terms of cost.

  The outermost layer and the recording layer of the present invention tend to have higher print density as the transparency is higher. The haze degree of the outermost layer (JIS K 7105) is preferably 30% or less, and the sum of the haze degrees of the outermost layer and the recording layer is preferably 50% or less. More preferably, the haze degree of the outermost layer is 15% or less, and the sum of the haze degrees of the outermost layer and the recording layer is 30% or less.

  In the present invention, since a fine pigment having an average particle diameter of 0.01 to 1 μm is used for the recording layer, a recording layer having a peak in the pore diameter distribution curve of approximately 0.2 μm or less, that is, no cracking of the coating film is provided. The above requirements can be satisfied by adjusting the balance of density, ink absorption speed, and ink absorption capacity. In addition, since it has a recording layer that has been thickened or gelled and dried, the glossiness of the outermost layer formed on the recording layer is easy to develop, and the peak in the pore diameter distribution curve of the outermost layer is approximately 0.2 μm or less, that is, coating. It is also possible to easily control film cracking.

According to a third aspect of the present invention, there is provided a method for producing an ink jet recording material in which a recording layer and an outermost layer are provided on a substrate, a means for supplying a continuous gas- permeable substrate, and a recording layer coating containing a fine pigment and a hydrophilic binder. A means for applying the liquid, a means for thickening or gelling the recording layer coating liquid, a means for drying the recording layer coating liquid until it exhibits a reduced rate drying rate, and a fine pigment on the formed recording layer. Inkjet manufactured using an inkjet recording body manufacturing apparatus having means for applying the coating liquid for outermost layer contained therein, and means for pressing and drying and peeling off a heated mirror drum while the outermost layer is in a wet state It is a manufacturing method of a recording medium.

That is, a step of supplying a base material (for example, a means for feeding out a base material in a wound state by a paper machine or a coating machine, or an unwinder), and a recording layer containing a fine pigment and a hydrophilic binder A step of applying a coating liquid (for example, means for applying a recording layer coating liquid by a coating machine) and a step of thickening or gelling the recording layer coating liquid (for example, means for applying a crosslinking agent, electronic A means for irradiating a line or a means for cooling), a step of drying the recording layer coating liquid until it exhibits a reduced rate drying rate (for example, a drying means such as hot air drying), and a fine pigment on the formed recording layer A step of applying a coating solution for the outermost layer containing (for example, means for applying the coating solution for the outermost layer with a coating machine), and a step of pressure-bonding to a heated mirror drum while the outermost layer is in a wet state ( for example, a well-known cast drum The apparatus used for a method of continuously producing. After crimping the mirror drum, and a step of peeling from the mirror surface drum, if necessary, a step of winding the winding shape.
It is manufactured continuously without winding it up between each means, that is, it is manufactured with one device, so that there is no variation in quality in the flow direction, as well as a high glossiness can get.

  Since the ink jet recording body manufactured in this manner is easily curled on the recording surface side, it is preferable to form an anti-curl layer on the back surface. The anti-curl layer can be formed at any location in the above manufacturing method, but in consideration of pressure bonding of the outermost layer to the mirror drum and subsequent drying, an anti-curl layer should be formed on the back surface after the outermost layer is formed. Is preferred. The anti-curl layer is preferably provided by coating a resin layer or a layer containing a resin and a pigment. Among them, it is preferable to laminate a thermoplastic resin such as polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, etc.). As a result, curling can be improved, the transportability of the obtained ink jet recording material can be improved, and the texture of the recording material can be brought close to that of photographic printing paper. In addition, you may mix | blend a pigment, dye, etc. in the thermoplastic resin used for a lamination.

"Ink "
As the ink used in the ink jet recording method of the present invention, a dye for forming an image and a liquid medium for dissolving or dispersing the dye are essential components, and if necessary, various dispersants, surfactants, It is adjusted by adding a viscosity adjuster, a specific resistance adjuster, a pH adjuster, an antifungal agent, a recording agent dissolution or dispersion stabilizer, and the like.

  Examples of the dyes and pigments used in the ink include direct dyes, acid dyes, basic dyes, reactive dyes, food dyes, disperse dyes, oil-based dyes, and various pigments. Can be used. The content of the dye or pigment is determined depending on the kind of the solvent component of the ink, the characteristics required for the ink, etc., but the ink used in the present invention is also similar to that in the conventional ink. There is no particular problem with blending, that is, use of about 0.1 to 20% by mass.

  Examples of the solvent for the ink used in the present invention include water and various water-soluble organic solvents such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol. Alkyl alcohols, ketones such as acetone and diacetone alcohol, or polyalkylene glycols such as polyethylene glycol and polypropylene glycol, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, thiodiglycol, Alkylene glycols having 2 to 6 alkylene groups such as xylene glycol and diethylene glycol, amides such as dimethylformamide, ethers such as tetrahydrofuran, glycerin Ethylene glycol methyl ether, diethylene glycol methyl (ethyl) ether, lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether and the like.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples. Moreover, unless otherwise indicated, the part and% in an example are solid content except water, and show a mass part and mass%, respectively.

[Cationic silica fine particles A]
After vapor phase silica having an average particle size of 1.0 μm (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil A300, average primary particle size: about 0.008 μm) was dispersed by a homomixer, the average particle size was 0.00. The mixture was pulverized and dispersed with a high-speed collision type homogenizer until the thickness became 08 μm to prepare a 10% aqueous dispersion. 10 parts of a cationic compound having a 5-membered ring amidine structure (product name: SC-700, molecular weight: 300,000) having a 5-membered ring amidine structure was added to the 10% aqueous dispersion, and further dispersed with a high-speed collision type homogenizer. A 10% aqueous dispersion having an average particle size of 0.15 μm was prepared.

[Cationic silica fine particles B]
The 10% aqueous dispersion of the cationic silica fine particles A was further dispersed with a high-speed collision type homogenizer to prepare a 10% aqueous dispersion having an average particle size of 0.1 μm.

[Cationic silica fine particles C]
(Adjustment of mesoporous silica)
8 g of ethylene oxide-propylene oxide copolymer (manufactured by Asahi Denka Kogyo Co., Ltd., Pluronic P123) and 240 g of a 2N hydrochloric acid aqueous solution were added to 60 g of water as a template and dissolved by stirring at 35 ° C. To this, 1.6 g of 1,3,5-trimethylbenzene was added with stirring. Further, 17 g of tetraethoxysilane was added with stirring, stirred at 35 ° C. for 20 hours, and allowed to stand at 90 ° C. for 24 hours. The obtained composite was filtered, washed with water and air-dried for 48 hours to obtain a composite powder of silica and template. The obtained powder was fired at 500 ° C. for 6 hours to obtain mesoporous silica.

(Preparation of cationic silica fine particles)
The obtained powder was dispersed with a homomixer and then pulverized and dispersed with a high-speed collision type homogenizer until the average particle size became 0.1 μm to prepare a 10% aqueous dispersion. 10 parts of a cationic compound having a five-membered ring amidine structure (trade name: SC-700M, molecular weight: 30,000) having a 5-membered ring amidine structure was added to the 10% aqueous dispersion, and further dispersed with a high-speed collision type homogenizer. A 10% aqueous dispersion having an average particle size of 0.3 μm was prepared.

[Cationic silica fine particles D]
(Preparation of active silicic acid aqueous solution)
Distilled water was mixed with a sodium silicate solution (trade name: No. 3 sodium silicate, manufactured by Tokuyama Corporation) having a SiO ₂ concentration of 30% by weight and a SiO ₂ / Na ₂ O molar ratio of 3.1, and a SiO ₂ concentration of 4.0% by weight. % Dilute aqueous sodium silicate solution was prepared. This aqueous solution was passed through a column packed with a hydrogen-type cation exchange resin (manufactured by Mitsubishi Chemical Corporation, trade name: Diaion SK-1BH) to prepare an active silicic acid aqueous solution. The obtained activated silicic acid aqueous solution had a SiO ₂ concentration of 4.0% by weight and a pH of 2.9. Further, Na ₂ O in terms of concentration was 0.1% by weight or less.

(Preparation of seed solution)
In a 5 liter glass reaction vessel equipped with a reflux, a stirrer, and a thermometer, 500 g of distilled water was heated to 100 ° C. While maintaining this hot water at 100 ° C., a total of 450 g of the above active silicic acid aqueous solution was added at a rate of 1.5 g / min to prepare a seed solution.

(Preparation of silica fine particle dispersion)
In the glass reaction vessel, 0.015 mol of ammonia was added to 950 g of the seed solution to stabilize it, and the mixture was heated to 100 ° C. A total of 550 g of the above active silicic acid aqueous solution was added to the seed solution at a rate of 1.5 g / min. After completion of the addition of activated silicic acid, the solution was kept at 100 ° C. and heated to reflux for 9 hours to obtain a silica fine particle dispersion. This dispersion was concentrated with an evaporator to prepare a 10% aqueous dispersion.

(Preparation of cationic silica fine particles)
10 parts of a cationic compound having a 5-membered ring amidine structure (product name: SC-700M, molecular weight: 30,000) having a 5-membered ring amidine structure is added to the 10% aqueous dispersion until the average particle size becomes 0.5 μm. The mixture was pulverized and dispersed with a high-speed collision type homogenizer to prepare a 10% aqueous dispersion.

[Alumina fine particles A]
After dispersing with a homomixer using high-purity alumina having an average particle size of about 3.0 μm (manufactured by Sumitomo Chemical Co., Ltd., trade name: AKP-G015, γ crystalline alumina, average primary particle size: about 0.1 μm) Further, the mixture was further dispersed with a high-speed collision type homogenizer, and the pulverization and dispersion operation was repeated with a liquid collision type homogenizer until the average particle size became 0.2 μm to prepare a 10% aqueous dispersion.

Example 1
[Coating fluid A]
100 parts of cationic silica fine particles A, 18 parts of polyvinyl alcohol (trade name: PVA-235, polymerization degree 3500, degree of saponification 88.5%, manufactured by Kuraray Co., Ltd.) as a binder, dispersant (manufactured by Toa Gosei Co., Ltd., trade name: Aron) SD-10) 0.05 part of a mixed aqueous dispersion (concentration: 15%) was prepared.
[Coating fluid B]
A 5% aqueous solution prepared by mixing 15 parts of an emulsion type acrylic resin latex (average particle size: 0.03 μm, Tg = −20 ° C.) and 5 parts of a release agent (ammonium oleate) as a binder with 100 parts of cationic silica fine particles B Prepared.
[Preparation of inkjet recording material]
After containing 1 g / m ² of borax in a base paper (thickness: 232 μm, tightness: 0.91 g / m ² ) having an air permeability of 72 seconds, cationic silica fine particles and The coating liquid A containing polyvinyl alcohol as a main component was applied so that the coating amount was 20 g / m ² , and the paint was rapidly gelled. The surface temperature of the coating layer at this time was 25 ° C.
Thereafter, the coating layer was dried to a reduction drying unit with hot air at 110 ° C. to obtain a recording layer. The surface temperature of the coating layer at this time was 70 ° C.
Subsequently, the coating liquid B was applied online on the recording layer so that the coating amount was 2 g / m ^2, and was pressed against a mirror drum having a surface temperature of 95 ° C. while it was wet. An ink jet recording material is produced by drying and peeling, and finishing is made of 65 parts high density polyethylene resin (density 0.954 g / cm ³ , melt index 20 g / 10 min) and low density polyethylene resin (density 0.924 g / cm) on the back side. ³ and a melt index of 4 g / 10 min), a polyethylene laminate layer comprising 35 parts was provided.
The pore peak of the outermost layer of the recording material thus obtained was 0.018 μm.

Example 2
An ink jet recording material was produced in the same manner as in Example 1 except that the recording layer was dried at a surface temperature of 110 ° C. and the recording layer was used as a drying end point. The pore peak of the outermost layer obtained was 0.020 μm.

Example 3
[Preparation of inkjet recording material]
Air permeability 30 seconds of the base paper (thickness 219Myuemu, bulk density 0.80 g / ^{m 2)} After borax was 1.5 g / ^{m 2} contained, on a surface on which borax has been applied, cationic silica The coating liquid A mainly composed of fine particles and polyvinyl alcohol was applied so that the coating amount was 16 g / m ² , and the paint was quickly gelled. The surface temperature of the coating layer at this time was 25 ° C.
Thereafter, the coating layer was dried to the end point of drying with hot air of 110 ° C. to obtain a recording layer. The surface temperature of the coating layer at this time was 110 ° C.
Subsequently, the coating liquid A was applied online on the recording layer so that the coating amount was 1 g / m ^2, and was pressed against a mirror drum having a surface temperature of 95 ° C. while it was wet. An ink jet recording material was prepared by drying and peeling. The pore peak of the obtained outermost layer was 0.023 μm.

Example 4
[Coating fluid C]
In 100 parts of cationic silica fine particles, 18 parts of polyvinyl alcohol (trade name: PVA-140, polymerization degree 4000, saponification degree 98%, manufactured by Kuraray Co., Ltd.) as a binder, dispersant (trade name: Aron SD-, manufactured by Toa Gosei Co., Ltd.) 10) 0.05 part of a mixed water dispersion (concentration: 15%) was prepared.
[Coating fluid D]
A 5% aqueous solution was prepared by mixing 15 parts of an emulsion type acrylic resin latex (average particle size: 0.03 μm, Tg = −20 ° C.) and 5 parts of a release agent (stearic amide) as a binder with 100 parts of alumina fine particles A. .
[Preparation of inkjet recording material]
After containing 0.1 g / m ² of borax in a base paper having a gas permeability of 38 seconds (thickness: 193 μm, tightness: 0.88 g / m ² ), on the surface coated with borax, cationic silica The coating liquid C mainly composed of fine particles and polyvinyl alcohol was applied so that the coating amount was 20 g / m ² , and the paint was quickly gelled. The surface temperature of the coating layer at this time was 30 ° C.
Thereafter, the coating layer was dried to the end point of drying with hot air of 110 ° C. to obtain a recording layer. The surface temperature of the coating layer at this time was 110 ° C.
Subsequently, the coating liquid D was applied online on the recording layer so that the coating amount was 1 g / m ^2, and was pressed against a mirror drum having a surface temperature of 95 ° C. while it was wet. An ink jet recording material was prepared by drying and peeling. The pore peak of the obtained outermost layer was 0.025 μm.

Example 5
[Preparation of inkjet recording material]
After containing 0.5 g / m ² of borax in a base paper (thickness: 194 μm, tightness: 0.90 g / m ² ) having an air permeability of 60 seconds, cationic silica is formed on the surface coated with borax. The coating liquid A mainly composed of fine particles and polyvinyl alcohol was applied so that the coating amount was 20 g / m ² , and the coating material was rapidly gelled. The surface temperature of the coating layer at this time was 25 ° C.
Thereafter, the coating layer was dried to the end point of drying with hot air of 110 ° C. to obtain a recording layer. The surface temperature of the coating layer at this time was 110 ° C.
Subsequently, the coating liquid D is applied online on the recording layer so that the coating amount is 2 g / m ² , and is pressed against a mirror drum having a surface temperature of 95 ° C. while it is wet. An ink jet recording material was prepared by drying and peeling. The pore peak of the outermost layer obtained was 0.020 μm.

Example 6
[Coating fluid E]
100 parts of cationic silica fine particles, 20 parts of polyvinyl alcohol (made by Kuraray Co., Ltd., trade name: PVA-235, polymerization degree 3500, saponification degree 88.5%) as a binder, dispersant (made by Toa Gosei Co., Ltd., trade name: Aron) SD-10) A 0.2 part mixed water dispersion (concentration: 15%) was prepared.
[Preparation of inkjet recording material]
Air permeability 402 sec of the base paper (thickness 170 [mu] m, bulk density 1.08 g / ^{m 2)} After borax was 0.05 g / ^{m 2} contained, on a surface on which borax has been applied, cationic silica The coating liquid C mainly composed of fine particles and polyvinyl alcohol was applied so that the coating amount was 16 g / m ² , and the paint was quickly gelled. The surface temperature of the coating layer at this time was 40 ° C.
Thereafter, the coating layer was dried to the end point of drying with hot air of 110 ° C. to obtain a recording layer. The surface temperature of the coating layer at this time was 110 ° C.
Subsequently, the coating liquid B is applied onto the recording layer so that the coating amount is 2 g / m ² , and is dried and peeled by pressing onto a mirror drum having a surface temperature of 95 ° C. while in a wet state. Thus, an ink jet recording material was produced. The pore peak of the outermost layer obtained was 0.018 μm.

Example 7
[Coating fluid F]
Cationic compound having a 5-membered ring amidine structure (product of Hymo Co., Ltd., product) by dispersing 100 parts of commercially available precipitated silica (manufactured by Tokuyama Corporation, trademark: Fine Seal X-37, particle size: about 2.6 μm) in water Name: SC-700, molecular weight: 300,000 (10 parts) is added, and as a binder , 30 parts of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: PVA-235, polymerization degree 3500, saponification degree 88.5%), and dispersing agent (Toa Gosei Co., Ltd., trade name: Aron SD-10) 0.2 part was added to prepare a mixed water dispersion (concentration: 20%).
[Preparation of inkjet recording material]
A coating liquid F mainly composed of silica and polyvinyl alcohol is applied to a base paper having a gas permeability of 60 seconds (thickness: 194 μm, tightness: 0.90 g / m ² ) so that the coating amount is 8 g / m ^2. An undercoat layer was previously provided on the base paper. The air permeability of the substrate including this undercoat layer was 50 seconds.
After containing 1 g / m ² of borax on the undercoat layer , an ink jet recording material was produced in the same manner as in Example 2. The pore peak of the outermost layer obtained was 0.020 μm. The results of quality evaluation are shown in Table 1.

Comparative Example 1
[Preparation of inkjet recording material]
Water absorbency 2 g / ^{m 2} art paper by the Cobb's method in air permeability 19000 seconds (thickness 120 [mu] m, bulk density 1.15 g / ^{m 2)} borax 0.05 g / ^{m 2} and contained, borax coating On the coated surface, the coating liquid A mainly composed of cationic silica fine particles and polyvinyl alcohol was applied so that the coating amount was 16 g / m ² , and the paint was rapidly gelled. The surface temperature of the coating layer at this time was 40 ° C.
Thereafter, the coating layer was dried to the end point of drying with hot air of 110 ° C. to obtain a recording layer. The surface temperature of the coating layer at this time was 110 ° C.
Subsequently, the coating liquid B was applied onto the recording layer so that the coating amount was 2 g / m ^2, and was pressed onto a mirror drum having a surface temperature of 95 ° C. while being wet. Because of the high air permeability, the moisture in the coating layer did not escape from the back surface and could not be peeled off from the drum. The pore peak of the outermost layer of the ink jet recording body thus obtained was 0.015 μm. The results of quality evaluation are shown in Table 1 .

Comparative Example 2
[Preparation of inkjet recording material]
After containing 0.5 g / m ² of borax in a base paper having a gas permeability of 38 seconds (thickness: 193 μm, tightness: 0.88 g / m ² ), silica and polyvinyl chloride are coated on the surface coated with borax. The coating liquid F containing alcohol as a main component was applied so that the coating amount was 16 g / m ² , and the paint was quickly gelled. The surface temperature of the coating layer at this time was 25 ° C.
Thereafter, the coating layer was dried to the end point of drying with hot air of 110 ° C. to obtain a recording layer. The surface temperature of the coating layer at this time was 110 ° C.
Subsequently, the coating liquid A was applied online on the recording layer so that the coating amount was 1 g / m ^2, and was pressed against a mirror drum having a surface temperature of 95 ° C. while it was wet. An ink jet recording material was prepared by drying and peeling.
Comparative Example 3

[Preparation of inkjet recording material]
In Example 1, an ink jet recording material was produced in the same manner as Example 1 except that the outermost layer was not applied. The pore peak of the outermost layer obtained was 0.015 μm.

Comparative Example 4
[Preparation of inkjet recording material]
In Example 1, an ink jet recording material was produced in the same manner as in Example 1 except that borax was applied after the recording layer became a rate-decreasing dry portion (the surface temperature of the recording layer was 70 ° C.). The layer was already cracked in the reduced rate drying section, and even if borax was applied, there was no improvement effect and the recording layer could not be provided.

Comparative Example 5
[Preparation of inkjet recording material]
In Example 1, an ink jet recording material was produced in the same manner as in Example 1 except that the outermost layer was applied before the recording layer became a reduced rate drying part (surface temperature of the recording layer 40 ° C.). The obtained outermost layer had two pore peaks of 0.020 μm and 1.00 μm. The results of quality evaluation are shown in Table 1.

Comparative Example 6
[Preparation of inkjet recording material]
In Example 1, an ink jet recording material was produced in the same manner as Example 1 except that the substrate did not contain borax. However, the coating film was cracked and the recording layer was not formed because the paint was not gelled by borax. Could not be established.
Example 8
[Preparation of inkjet recording material]
In Example 1, an ink jet in a similar manner air permeability of 30 seconds, water absorbency of 130 g / ^{m 2} base paper (thickness 255Myuemu, bulk density 0.75 g / ^{m 2)} as in Example 1 except for using A recording body was produced. The pore peak of the outermost layer obtained was 0.015 μm. The results of quality evaluation are shown in Table 1.

[Evaluation methods]
The pore distribution peak, ink absorptivity, image quality, and gloss of the outermost layer of the inkjet recording materials obtained in Examples 1 to 8 and Comparative Examples 1 to 6 were evaluated by the following methods. A commercially available ink jet printer was used for printing. (Manufactured by EPSON, trademark: PM-950C, printing mode: PM photo paper clean mode)

(Peak distribution peak)
The peak in the prescribed pore diameter distribution curve of the present invention will be described. As a measurement method, in order to avoid the influence of the support, the coating layer was peeled off with a cutter or the like and used for measurement. The pore distribution was determined by a mercury intrusion method using a Micrometrics Posizer 9320 (manufactured by Shimadzu Corporation). The measurement of the pore diameter by the mercury intrusion method was calculated using the following formula derived assuming that the cross section of the pore was circular.
R = -2γCOSθ / P
In the formula, R: pore radius (2R = pore diameter), γ: surface tension of mercury, θ: contact angle, and P: pressure, respectively.
The surface tension of mercury is 482.536 dyn / cm, the working contact angle is 130 °, the low pressure part of mercury pressure (0 to 30 psia, measurement pore radius: 180 to 3 μm) and the high pressure part (0 to 30001 psia, measurement pores) Radius: 3 to 0.003 μm).
The pore diameter distribution is obtained by gradually changing the pressure applied to mercury using the above principle, measuring the volume of mercury entering the pores at that time, that is, the pore volume V, and converting it according to the above formula. The relationship between the pore diameter (2R) and the pore volume is drawn, and the differential coefficient dV / d (2R) of this relationship curve is determined as the vertical axis, and the pore diameter 2R is determined as the horizontal axis. The pore diameter distribution curve of the coating layer usually has 1 to several peaks.

(Ink absorbency (print spots))
Green solid printing was performed on the recording medium, and whether or not there were solid printing spots was visually observed and evaluated in the following four stages. Print spots are a phenomenon that occurs when the ink that has been struck first is not completely absorbed by the coating layer of the ink jet recording body and the next ink comes and overlaps on the surface. , Appear prominently.
A: No printed spots are seen.
○: There are some printed spots, but there is no problem in practical use.
(Triangle | delta): The level which has a printing problem and has a problem practically.
X: Many printing spots.

(Image quality (roundness of dots))
An ISO-400 image ("high-definition color digital standard image data ISO / JIS-SCID", p13, image name: fruit basket) was printed, and the uniformity (background part) of the image was visually observed and evaluated. If the dot is a perfect circle, the portion where the dot and the dot overlap each other becomes extremely uniform, but the uniformity of the dot is lacking as the dot deviates from the roundness.
○: The image is uniform and spots are not visible (dots are perfect circles and no jagged edges are seen at the edges).
X: The image is non-uniform and spots are seen (dots are not round and the edges are jagged).

(Glossy)
ISO-400 images ( "High-definition color digital standard image data ISO / JIS-SCID", p13, image name: Fruit basket) was printed, it was visually from the side of the angle to the printing section, on the following criteria evaluated.
A: There is a glossiness similar to that of a silver salt photograph.
○: There is a glossiness slightly inferior to silver halide photographs.
Δ: Some cockling occurs and glossiness is slightly inferior.
X: It is equal to or less than a general commercially available glossy ink jet recording material.
XX: Matte without gloss.

Example 9
[Coating fluid G]
20 parts of temperature-sensitive polymer (ALB-8.01, temperature-sensitive point 15 ° C., glass transition temperature 90 ° C., manufactured by Asahi Kasei) 20 parts of cationic silica dispersion A that thickens and gels as a binder and gelling agent by cooling. Was added to prepare a coating solution G having a concentration of 12%.
[Coating fluid H]
100 parts of cationic colloidal silica (Snowtex AK, manufactured by Nissan Chemical Co., Ltd.) and 5 parts of polyvinyl alcohol (manufactured by Kuraray Co., Ltd., trade name: PVA-235, polymerization degree 3500, saponification degree 88.5%), stearic acid as a release agent A cast coating solution having a concentration of 15% was prepared by blending 2 parts of amide.
[Preparation of inkjet recording material]
A coating liquid F mainly composed of silica and polyvinyl alcohol is applied to a coating amount of 10 g / m ² on a base paper (thickness: 194 μm, tension 0.90 g / m ² ) having an air permeability of 60 seconds. The recording layer was previously provided on the base paper. The air permeability of the base paper including this recording layer was 43 seconds.
On this recording layer, the coating liquid G was applied so as to be 5 g / m ² , then cooled to 10 ° C. using a cold air machine, and the coating liquid was gelled. Dried. Subsequently, the coating liquid H was applied so that the coating amount was 1 g / m ² , and while in a wet state, it was pressed against a mirror drum having a surface temperature of 90 ° C., dried and finished, and an inkjet recording medium was prepared. Obtained.

Comparative Example 7
In Example 9, after the coating liquid G was applied, it was dried without cooling, and then the coating liquid H was applied so that the coating amount was 1 g / m ² , and wet. While in this state, it was pressed against a mirror drum having a surface temperature of 90 ° C., dried and finished to obtain an ink jet recording paper.

[Evaluation methods]
The pore distribution peak, ink absorptivity, image quality and gloss of the outermost layer of the ink jet recording materials obtained in Example 9 and Comparative Example 7 were evaluated by the following methods. A commercially available ink jet printer was used for printing. (Manufactured by EPSON, trademark: PM-950C, printing mode: PM photo paper clean mode)

  As is apparent from Tables 1 and 2, the ink jet recording material obtained in the present invention has excellent gloss, good ink absorption, and image quality is free from cracks in the image recording layer (recording layer and outermost layer). Since the roundness of the dots is high, it is very good.

  The method for producing an ink jet recording material of the present invention can provide an ink jet recording material that is most suitable for a dye-based or pigment-based ink jet printer that aims at photographic image quality and that ejects ink quickly.

Claims (10)

In the method for producing an ink jet recording material in which a recording layer and an outermost layer are provided on a base material , the air permeability (JIS-P-8117) of the base material is 30 to 500 sec , and the recording layer has an average particle diameter of 0.01 to A recording layer coating liquid containing 1 μm fine pigment and a hydrophilic binder is applied to one side of the substrate and dried, and at the same time as the application or at the time of drying, the coating liquid exhibits a reduced rate of drying. Before being formed, the applied coating liquid is formed by thickening or gelling, and the outermost layer has an average particle diameter on the recording layer after the recording layer shows a reduced drying rate. Is coated with a coating solution for the outermost layer containing a fine pigment of 0.01 to 1 μm, and while the outermost layer is in a wet state, it is pressed onto a heated mirror drum and dried and peeled off. A method for producing an ink jet recording material. In the method for producing an ink jet recording material in which a recording layer and an outermost layer are provided on a base material , the air permeability (JIS-P-8117) of the base material is 30 to 500 sec , and the hydrophilic binder used in the recording layer and a crosslinking reaction A coating liquid having a cross-linking agent capable of coating is applied to one surface of a substrate, and after the coating liquid is dried or without drying, a fine pigment having an average particle diameter of 0.01 to 1 μm is applied to the coated surface. A recording layer coating solution containing a hydrophilic binder is applied and dried to form a recording layer. After the recording layer exhibits a reduced rate of drying, an average particle size of 0. 0 is formed on the recording layer. A coating liquid for the outermost layer containing a fine pigment of 01 to 1 μm is applied, and while the outermost layer is in a wet state, it is formed by pressure-bonding to a heated mirror drum and drying and peeling. A method for producing an ink jet recording material. The surface of the substrate is impregnated or coated with 0.01 to 1.5 g / m ² of a boron compound, and the recording layer contains a polymer capable of crosslinking reaction with the boron compound. 3. A method for producing an ink jet recording material according to 1 or 2. The fine pigment contained in the recording layer coating liquid is selected from gas phase method silica, mesoporous silica, colloidal material of wet method silica produced by condensing activated silicic acid, alumina oxide, and alumina hydrate. The method for producing an ink jet recording material according to claim 1, comprising at least one kind. The fine pigment contained in the coating solution for the outermost layer is gas phase method silica, mesoporous silica, wet method silica colloid produced by condensing activated silicic acid, colloidal silica, alumina oxide, and alumina hydrate 5. The method for producing an ink jet recording material according to claim 1, comprising at least one selected from the group consisting of: The average particle diameter of the fine pigment contained in the coating liquid for the outermost layer is smaller than the average particle diameter of the fine pigment contained in the coating liquid for the recording layer. Production method. The inkjet layer according to any one of claims 1 to 6, wherein a laminate layer containing a polyolefin resin is provided on the surface of the substrate that does not have the recording layer and the outermost layer after the outermost layer is formed. A method for manufacturing a recording medium. The method for producing an ink jet recording material according to claim 1, wherein the coating amount of the recording layer is 3 to 60 times the coating amount of the outermost layer. Tightness (JIS-P-8118) of the substrate is 0.8 to 1.1 g / m ² The method for producing an ink jet recording material according to claim 1, wherein the thickness is 160 to 270 μm. In a method for producing an ink jet recording material in which a recording layer and an outermost layer are provided on a substrate, a step of supplying a substrate having a continuous air permeability (JIS-P-8117) of 30 to 500 sec, a fine pigment and a hydrophilic binder A step of applying a recording layer coating solution containing a step, a step of thickening or gelating the recording layer coating solution, and a step of drying the recording layer coating solution until it exhibits a reduced rate of drying. Using a coating apparatus having a step of applying a coating solution for the outermost layer containing a fine pigment on the recording layer, and a step of pressing and drying and peeling off a heated mirror drum while the outermost layer is in a wet state The manufacturing method of the inkjet recording body manufactured.