JP2006001028A - Inkjet recording body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording body excellent in recordability with both dye ink and pigment ink. <P>SOLUTION: In an inkjet recording body, in which an ink accepting layer is laminated onto a support, the ink accepting layer has at least two layers or an outermost surface coating layer and an inside coating layer arranged between the outermost surface coating layer and the support under the condition that the outermost surface coating layer includes mainly a wet process silica having an average secondary particle diameter of not more than 500 nm and, at the same time, the inside coating layer adjoining the outermost surface coating layer includes a vaporphase method silica having an average secondary particle diameter of not more than 700 nm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording material excellent in recording suitability for both dye ink and pigment ink. More specifically, the present invention relates to an ink jet recording material capable of high-speed recording, having an image dot shape close to a perfect circle, high image color density and gloss, and extremely good image uniformity.

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

  In recent years, the rapid spread of printers and higher definition and speed have been advanced, and accordingly, ink jet recording bodies have been required to have an improved ink absorption speed than before, and further, recorded images of images taken by digital cameras. On the other hand, there is a strong demand for the realization of high uniformity comparable to silver salt photography. Further, in order to bring the quality of a recorded image closer to that of a photographic image, further improvement in the color density and glossiness of the recorded image is desired.

  On the other hand, in order to realize image storage stability equivalent to silver salt photography, improvement of the ink itself has also been proposed, and an aqueous dye ink using a highly hydrophilic colorant that occupies the mainstream of conventional inks for inkjet recording Along with (hereinafter referred to as dye ink), ink containing a hydrophobic coloring pigment having excellent water resistance and light resistance as a colorant (hereinafter referred to as pigment ink) is often used.

  When pigment ink is used as ink for ink jet recording, most of the colored pigment contained in the ink is retained on the recording surface of the ink jet recording body, so the pigment ink is applied to the high gloss ink jet recording body for dye ink. As a result, the fixability of the pigment ink and the scratching property of the pigment ink image are often insufficient. For this reason, there has been a strong demand for the appearance of recording media capable of printing high-quality images for both dye inks and pigment inks.

In order to impart the suitability of pigment ink to a high-gloss ink jet recording material for dye ink, the ink absorption of the ink receiving layer and the pigment fixing property of the pigment ink are improved, and the glossiness of the coating surface is achieved. There is a need.
As a means for increasing the glossiness of a recording medium, Japanese Patent Laid-Open No. 2003-326834 (Patent Document 1) discloses an inorganic material used as an uppermost layer as a top surface layer in a recording medium in which two or more ink receiving layers are laminated. There has been proposed a recording medium having a layer configuration in which the average particle size of the fine particles is smaller than the average particle size of the inorganic fine particles used in the lower layer adjacent to the base material. Japanese Patent Application Laid-Open No. 2001-171228 (Patent Document 2) discloses a recording material having no ink dullness and excellent ink absorbency by using polymer latex and solid fine particles for the lower layer and gas phase method silica for the surface layer. is doing. However, in any of the methods, the outermost inorganic fine particles are primary particles of colloidal silica or secondary particles of vapor phase method silica, and it is difficult to achieve both fixing of the pigment ink and glossiness.

  Japanese Patent Laid-Open No. 2001-277712 (Patent Document 3) discloses at least one ink receptive inner layer on a non-absorbent support and an ink receptive outermost layer laminated on the outer surface of the inner layer. And the ink receptive inner layer contains silica gel fine particles, and the ink receptive outermost layer is 1 μm or less selected from the silica compound fine particles, aluminosilicate, and α, θ, δ, and γ-alumina. An IJ recording medium containing pigment fine particles having an average particle diameter has been proposed. Although this method can provide a recording material excellent in gloss, there is a problem that the color tone of the image changes when alumina is used as the outermost ink-receiving layer, particularly when the image quality is not clear and the printing density is low.

In JP-A-2003-335045 (Patent Document 4), in an inkjet recording paper having one or more porous layers on a non-water-absorbing support, the outermost layer is thermoplastic and has an average particle size of 100 nm or less. In addition, a recording medium containing inorganic fine particles having an average primary particle diameter of 20 nm or more has been proposed. However, in this method, since the primary particle diameter of the inorganic fine particles is large, the printing density is lowered for both the dye ink and the pigment ink, the image is dull, and the image quality is deteriorated.
In Japanese Patent Application Laid-Open No. 2002-234248 (Patent Document 5), an image recording body in which the outermost porous layer is composed of cationic inorganic fine particles and cationic or nonionic thermoplastic resin particles is disclosed in Japanese Patent Application Laid-Open No. 7-101142. In the publication (Patent Document 6), an ink jet recording sheet having a glossy expression layer composed of colloidal particles having an average particle diameter of 200 nm or less and a synthetic polymer latex is proposed. By this method, the thermoplastic resin particles contained in the outermost layer can exhibit a certain level of gloss on the surface of the recording material after drying, but the gloss is still insufficient and the ink absorbency is not satisfactory. There wasn't.

  Accordingly, a recording medium in which an ink receiving layer is coated by a cast coating method has been proposed in order to impart higher gloss. In Japanese Patent No. 3402514 (Patent Document 7), amorphous silica / alumina is used for the surface layer of the ink receiving layer, and JP-A No. 2003-205676 (Patent Document 8) and JP-A No. 2000-141868 (Patent Document 9). JP-A 2000-2111248 (Patent Document 10) proposes an ink jet recording sheet using alumina as a surface layer and having a heated mirror surface roll with a pressure mirror surface gloss finish when the surface layer is wet. As a result, it is possible to obtain a recording medium having a glossiness close to a mirror surface, but since the surface layer is made of alumina, the color of the dye ink is poor and the releasability from the mirror surface roll is poor. It was difficult to obtain a feeling recording body.

  In JP-A-11-11011 (Patent Document 11), the outermost layer of the ink receiving layer contains porous cationic colloidal particles such as silica and cationic latex as essential components, and cast at a temperature higher than the glass transition temperature of the latex. Coated IJ recording sheets have been proposed. In this method, since the outermost layer is cationized silica, the coloring property of the dye ink is good, and since it is porous, the fixing property of the pigment ink is also excellent, and at a temperature higher than the glass transition temperature of the latex. By being cast-coated, a recording material excellent in gloss can be obtained. However, this method has the disadvantages that the coating film is prone to cracking because the outermost layer and the ink receiving layer below it use gas phase method silica, and it takes a long time to dry the coating film for crack control. .

In the case of a non-liquid-absorbing substrate, in WO 03/039881 (Patent Document 12), the outermost surface coating layer is pressed against a heated mirror surface, for example, a mirror drum, and dried while it is wet. Thus, a so-called nip casting method in which a mirror surface is copied onto a coating layer is disclosed. Immediately before the coating layer provided on the substrate is pressed against the mirror drum, the outermost surface coating liquid is applied between the coating layer surface on the press roll and the mirror drum, and immediately pressed. By allowing them to dry, the outermost surface coating layer can be mirror-finished.
However, in this method, when a water-soluble binder component is contained in the outermost surface coating liquid, the mirror drum becomes dirty and the gloss is lowered, or when a finely aggregated fine pigment is used, the outermost surface coating layer is used. There are drawbacks such as easy cracking.

JP 2003-326834 A, pp. 3-6 JP 2001-171228, pp. 3-5 JP 2001-277712 A, pages 4-9 JP 2003-335045, pages 3 and 12 JP 2002-234248, pp. 3-8 JP-A-7-101142, pages 4-6 and 8-9 Japanese Patent No. 3402514, pages 3-5 JP2003-205676, pages 3-5 and 8 JP 2000-141868, pages 3-5 JP 2000-21248, pages 3-5 JP-A-11-11011, pages 3-5 International Publication Number WO03 / 039881

  The present invention has been made to solve the above problems, and to provide an ink jet recording material that has good ink absorbability, enables high-speed recording, and has extremely good color density and glossiness. In addition, since an image as high as a silver salt photograph equivalent to that of a dye ink can be obtained, an ink jet recording material for dye and pigment ink is provided.

  The ink jet recording body of the present invention is an ink jet recording body in which an ink receiving layer is laminated on a support, and the ink receiving layer is disposed between the outermost surface coating layer and the outermost surface coating layer and the support. The innermost coating layer has at least two inner coating layers, and the outermost surface coating layer contains wet-process silica having an average secondary particle diameter of 500 nm or less as a main component and is adjacent to the outermost coating layer. The coating layer contains gas phase method silica having an average secondary particle diameter of 700 nm or less.

The wet process silica contained in the outermost surface coating layer is cationized by at least one cationizing agent selected from a silane coupling agent having an amino group, a water-soluble polymer compound having an ammonium salt, and an aluminum compound. Silica is preferred.
The wet method silica contained in the outermost surface coating layer is preferably a silica colloid obtained by condensing active silicic acid or a gel method silica colloid.
The outermost surface coating layer is preferably a layer obtained by applying a coating liquid containing a cationic aqueous emulsion resin, and the average particle diameter of the emulsion resin is more preferably 100 nm or less.
The coating liquid for forming the outermost surface coating layer preferably has a pH of 8 or less and a viscosity of 100 mPa · s or less.
It is preferable that the peak in the pore diameter distribution curve of the outermost surface coating layer and the inner coating layer adjacent to the outermost surface coating layer is substantially only 100 nm or less.
The gas phase method silica contained in the inner coating layer is cationized by at least one cationizing agent selected from a silane coupling agent having an amino group, a water-soluble polymer compound having an ammonium salt, and an aluminum compound. Is preferred.
The support is preferably a non-absorbable support.
After the inner coating layer is applied, the outermost surface coating layer is applied while the outermost surface coating layer is in a wet state after the coating layer has come to exhibit a reduced rate of drying. It is preferable that the ink-receiving layer is obtained by press-contacting to a heated mirror drum and then drying.

  The ink jet recording material of the present invention has good ink absorptivity and enables high-speed recording, the dots of the ink image are close to a perfect circle, the color density and gloss of the image are extremely good, and the dye ink is also a pigment ink Since a high image equivalent to a silver salt photograph can be obtained, it also has an effect of excellent pigment ink suitability.

"About support"
There are no particular restrictions on the type, shape, dimensions, etc. of the support used in the ink jet recording material, but a non-absorbent substrate is preferred from the viewpoint of cockling after printing or photographic texture. In the case of an absorptive support, it is preferable that the paper thickness and the sizing degree are high.

  Examples of the absorbent support include fine paper, medium paper, coated paper, art paper, and cast coated paper. Examples of the non-absorbent support include plastic films such as polyethylene terephthalate, polyvinyl chloride, polycarbonate, polyethylene, and polypropylene, synthetic paper, and white films. Further, a non-absorbent resin-coated sheet obtained by coating these supports with a non-ink medium absorbent resin may be used. As the non-ink medium-absorbing resin, a polyolefin resin such as polyethylene and polypropylene, a cellulose diacetate resin, a polyester resin, or a mixture thereof can be used as a main component. It is preferable because of good adhesion, and polyethylene is particularly preferable.

  In addition, the surface of the support on which the ink receiving layer is formed may be subjected to an adhesion treatment or an adhesion treatment in advance for the purpose of improving the adhesion between the support and the ink receiving layer. In particular, when resin-coated paper is used as the non-absorbent support, it is preferable to subject the surface of the resin coating layer to corona discharge treatment or to provide an undercoat layer made of gelatin, polyvinyl alcohol or the like.

  It is also possible to perform processing such as transportability improvement processing, antistatic processing, and antiblocking processing on the back surface of the support. The back surface treatment may be, for example, a chemical treatment such as an antistatic agent and an antiblocking agent, or may be another one appropriately added such as providing a coat layer.

  The smoothness of the support is not particularly limited, but a Beck smoothness of 300 seconds (Oken type, J.TAPPI No. 5) or more is preferable because a high gloss and high smooth surface can be obtained. Further, the opacity of the support is not particularly limited, but it is preferable that the opacity (JIS P8138) is 85% or more and a silver salt photograph-like appearance (particularly visual whiteness) can be obtained. More preferably, it is 93% or more.

About the ink receiving layer
In the present invention, the ink receiving layer is composed of a plurality of coating layers laminated together. Among these coating layers, the outermost surface coating layer and the inner coating layer directly adjacent thereto are important.
In addition to increasing the surface gloss of the ink receiving layer, the purpose of providing the outermost surface coating layer is to quickly fix the dyes or pigments in the ink so that high color development (high color density) and uniform image (image dot shape) In order to obtain high roundness). On the other hand, the purpose of providing the inner coating layer is to absorb and fix the colorant and the solvent in the ink that has not been absorbed in the outermost surface coating layer and permeated through it. High smoothness and film formability for obtaining high gloss are required. In addition, one or more undercoat coating layers may be provided between the support and the inner coating layer for the purpose of improving the adhesion between the support and the inner coating layer or improving ink absorption. Good.

  As a result of extensive studies, the inventors have made the outermost surface coating layer of wet-process silica and contain 20% by mass or more of wet-process silica having an average secondary particle diameter of 500 nm or less, and the outermost surface coating. By configuring the ink receiving layer using vapor phase method silica having an average secondary particle diameter of 700 nm or less on the inner coating layer adjacent to the coating layer, it becomes easy to express a desired gloss on the outermost surface coating layer, It has been found that the ink jet recording material is excellent in ink absorbability and fixability of pigment ink, and the recorded image has extremely good uniformity.

"About the inner coating layer constituting the ink receiving layer"
The inner coating layer contains gas phase method silica having an average secondary particle diameter of 700 nm or less and a binder for holding the gas phase method silica on a support. Vapor phase silica is also called fumed silica, and is generally made by flame hydrolysis. Specifically, a method for producing silica by burning silicon tetrachloride with hydrogen and oxygen is generally known, but instead of silicon tetrachloride, such as methyltrichlorosilane and / or trichlorosilane is used. Silanes can also be used alone or mixed with silicon tetrachloride. When wet-type silica is used for the inner coating layer, the transparency of the coating layer is lowered and the sharpness of the image quality is inferior, and when alumina is used, the coloring property of the dye ink is lowered. Is seen.

  The vapor phase method silica contained in the inner coating layer of the present invention needs to have an average secondary particle size of 700 nm or less. When the average secondary particle diameter is larger than 700 nm, the smoothness and film formability of the coating layer are lowered, and the surface gloss of the outermost surface coating layer is lowered.

  The average secondary particle diameter of the vapor phase method silica can be adjusted by, for example, a method of applying a strong force by mechanical means, a so-called breaking down method (a method of subdividing 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 product with a bowl-shaped stirring bar), a sand grinder, a nanomizer and the like. In order to reduce the particle size, classification and pulverization can be repeated.

  The average secondary particle diameter of the pigment particles used in the present invention is adjusted to 200 g of an aqueous dispersion having a concentration of 3% by mass from this pigment regardless of whether the pigment is in the form of powder or slurry. Then, after applying this to a homomixer and stirring and dispersing at 1000 rpm for 30 minutes, this dispersion was immediately subjected to observation with an electron microscope (SEM and TEM), and an electron micrograph of 10,000 to 400,000 times was taken. The average particle diameter of particles existing in an area of 5 cm × 5 cm square is measured and averaged (see “Fine Particle Handbook”, Asakura Shoten, p52, 1991).

  In order to improve the water resistance and storage stability of the recorded image, the vapor phase silica used for the inner coating layer is 1) a silane coupling agent having an amino group, 2) a water-soluble polymer having an ammonium salt, and 3) aluminum. It is preferable to use a material cationized with at least one cationizing agent selected from compounds. The cationization of silica will be described later. In addition, a cationic compound can be added to the inner coating layer in order to improve the storage stability of the recorded image. The cationic compound will be described later.

  As the binder used for the inner coating layer, known materials for ink jet recording can be used, for example, polyvinyl alcohol, polyvinyl pyrrolidone, casein, soybean protein, synthetic proteins, starch, carboxymethylcellulose, cellulose derivatives such as methylcellulose, etc. Water-soluble resin, styrene-butadiene copolymer, methyl methacrylate-butadiene copolymer, conjugated diene polymer latex, acrylic polymer latex, ethylene-vinyl acetate copolymer and other vinyl polymer latex, aqueous Examples thereof include latex adhesives such as polyurethane resins. Among them, polyvinyl alcohol having high adhesiveness with a pigment such as silica is preferably used. In particular, in order to improve the balance between film formability and ink absorbability, it is preferable to use polyvinyl alcohol having a degree of polymerization of 2000 or more, and more preferably polyvinyl alcohol having a degree of polymerization of 3600 to 5000. In order to improve ink absorptivity etc., two or more binder materials (for example, a mixture of two or more water-soluble resins, a mixture of one or more water-soluble resins and one or more latexes) are used. Also good.

The dry solid content mass ratio of the pigment and the water-soluble resin in the inner coating layer is preferably in the range of 100/50 to 100/2. In order to further improve the balance between ink absorptivity and coating film strength, it is preferably 100/30 to 100/5, and more preferably 100/25 to 100/10.
The dry solids coating weight of the inner coating layer, without limitation, is preferably generally 1 to 40 g / ^{m 2} approximately, more preferably 5 to 30 g / ^{m 2.} If the coating amount is too small, the high-resolution and high-speed printer may have insufficient ink absorbability, and if it is too large, it may be difficult to control cracks in the coating film.
In order to improve the balance between the ink absorption speed and the ink absorption capacity, the coating amount of the inner coating layer is preferably 3 to 50 times, more preferably 7 to 30 times the coating amount of the outermost surface coating layer. More preferably, the ratio is more preferably 10 to 25 times.

In addition to the pigment and binder, the inner coating layer includes various auxiliary agents such as dispersants, thickeners, antifoaming agents, colorants, antistatic agents, and antiseptics that are used in general coated paper production. May be contained appropriately.
Further, one or more coating layers may be appropriately laminated between the support and the inner coating layer for the purpose of improving the adhesion between the support and the inner coating layer or improving the ink absorbability. Good.

  The inner coating layer is preferably formed so as not to cause cracks. The crack generation control method is not particularly limited. For example, the inner coating layer is applied at the same time as the inner coating layer is being formed, and the inner coating layer is being dried. The method of forming a film by thickening or cross-linking the applied paint layer (the layer in which the paint has been applied and has not been completely dried) can be mentioned. As a specific example, a hydrophilic resin (for example, polyvinyl alcohol) that forms a hydrogel by electron beam irradiation is contained in the coating material for the inner coating layer, and immediately after coating or during the drying of the formed coating layer, Before the paint layer shows a decreasing rate of drying, this paint layer is irradiated with an electron beam to thicken the paint layer (hydrogel), or formed on the polyvinyl alcohol-containing paint layer immediately after coating. In the course of drying of the paint layer, before the paint layer exhibits a decreasing rate of drying, a compound having crosslinkability to polyvinyl alcohol (for example, an aldehyde-based cross-linking agent such as glyoxal, ethylene glycol diglycidyl ether, etc. Epoxy-based crosslinking agents, vinyl-based crosslinking agents such as bisvinylsulfonylmethyl ether, and boron-containing compounds such as aluminum alum, boric acid and borax) Thickening, methods and the like of crosslinking include the paint layer by.

As coating devices for forming the inner coating layer, various coating devices such as blade coaters, air knife coaters, roll coaters, bar coaters, gravure coaters, rod blade coaters, lip coaters, curtain coaters and die coaters are available. Can be mentioned. When two or more coating layers are applied, it is preferable to use a method in which the upper layer is applied onto the lower layer while the lower layer is not dried, that is, a wet-on-wet method.
Moreover, as a method of performing electron beam irradiation, (1) coating, electron beam irradiation, and drying may be repeated, or (2) after coating and electron beam irradiation, the next layer may be applied and dried. There is a method of (3) applying multiple layers simultaneously and irradiating with an electron beam.

"About the outermost surface coating layer constituting the ink receiving layer"
The outermost surface coating layer formed on the inner coating layer contains a wet process silica having an average secondary particle diameter of 500 nm or less, and a binder for holding the wet process silica in the inner coating layer. Wet process silica is usually produced from silicon dioxide (SiO ₂ ), mainly silica sand. Examples of the wet method silica include a colloidal material obtained by condensing gel method silica composed of secondary agglomerated particles, precipitation method silica, and active silicic acid.

The amorphous silica of the gel method, for example, produces a silicate sol by mixing sodium silicate and sulfuric acid made from high-purity silica sand. The silicic acid sol gradually polymerizes to form primary particles, and further, a three-dimensional aggregate is formed and gelled. This silica is micronized and pulverized. That is, in the gel method, reaction polymerization is performed on the acidic side, and the mixture is allowed to stand until it becomes a gel (sorbet shape), washed with water and dried to obtain an amorphous silica of the gel method.
Further, the precipitated amorphous silica is obtained by reaction polymerization on the alkali side, precipitation as it is, and drying.
The colloidal material obtained by condensing the active silicic acid is obtained by adding an alkali to a colloidally dispersed silica seed aqueous dispersion, and at least one selected from an aqueous solution of active silicic acid and alkoxysilane. This is produced by a method of preparing a dispersion of secondary agglomerated silica by gradually adding a feed solution consisting of the above to grow silica fine particles, and this method is described in JP-A-2001-354408 and the like. .

  Among these wet method silicas, preferred are gel method silica or colloidal products obtained by condensing activated silicic acid, and more preferred is gel method silica. This is a secondary agglomerate with a smaller pore size and pore volume between primary particles compared to other wet-process silica, and the secondary particle size can be easily reduced, so both ink absorbency and gloss can be achieved. It is because it can plan.

  In the present invention, wet-process silica having an average secondary particle diameter of 500 nm or less is used for the outermost surface coating layer. Since wet-process silica has secondary agglomerated particles, the outermost surface coating layer has a porous structure, and wet-process silica has smaller pore diameters between primary particles than gas-phase process silica and alumina. Therefore, a fine porous structure having an optimum pore diameter distribution can be formed. As a result, the fixability of the pigment ink is good, high gloss and image color density are expressed, and a high ink absorption rate well balanced with these performances can be expressed.

When the average secondary particle diameter of the wet method silica is larger than 500 nm, the transparency of the outermost surface coating layer is lowered, so the color density of the recorded image is lowered and the gloss of the outermost surface coating layer surface is also lowered. To do. In addition, when monodispersed colloidal silica consisting only of primary particles is used as the main component for the outermost surface coating layer, the outermost surface coating layer surface should have a high gloss but a fine porous structure should be formed. Therefore, the ink absorption rate is too low and the fixability of the pigment ink is insufficient.
In addition, the primary particle diameter of the wet-aggregated wet method silica used in the outermost surface coating layer is not particularly limited, but is preferably 3 to 20 nm, and more preferably 5 to 15 nm. If it is smaller than 3 nm, the pores between the primary particles are too small and the ink absorptivity is lowered, and if it is larger than 20 nm, the color density of the image is lowered, which is not preferable.

  When wet-process silica having an average secondary particle size of 500 nm or less is contained in the outermost surface coating layer in an amount of 20% by mass or more, the fixability of pigment ink can be greatly improved while exhibiting high gloss and ink absorbability. It is preferable because it is possible. When the content of the wet process silica having an average secondary particle diameter of 500 nm or less is less than 20% by mass, the gloss and the fixability of the pigment ink tend to be insufficient.

  The particle diameter of the wet process silica used in the outermost surface coating layer can be adjusted by, for example, a method of applying a strong force by mechanical means, a so-called breaking down method (a method of subdividing 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 product with a bowl-shaped stirring bar), a sand grinder, a nanomizer and the like. In order to reduce the particle size, classification and pulverization can be repeated.

  In order to balance the performance of gloss, pigment ink fixability, and ink absorbability, the outermost surface coating layer is not limited to wet silica having an average secondary particle size of 500 nm or less, but other inorganic materials. The pigment and the organic pigment can be appropriately mixed, for example, in a content of less than 20% by mass within a range not impairing the action effect of the wet process silica.

In order to further improve the gloss while maintaining the fixability of the pigment ink, it is effective to use a wet-type colloidal silica, preferably a cationic colloidal silica, in the outermost surface coating layer. By using colloidal silica composed of primary particles and secondary agglomerated silica in combination, the high gloss of colloidal silica and the fixability and ink absorptivity of the pigment ink possessed by the secondary agglomerated silica particles can be expressed simultaneously. The mixing ratio of colloidal silica and secondary agglomerated silica is preferably 30/70 to 70/30, and particularly preferably 40/60 to 60/40.
The primary particle of colloidal silica is preferably 10 to 100 nm, more preferably 20 to 60 nm. If the primary particles are smaller than 10 nm, ink absorption is inhibited, and if the primary particles are larger than 100 nm, the color density of the image is lowered, which is not preferable.

  In order to improve the water resistance and storage stability of recorded images, the wet method silica used for the outermost surface coating layer is 1) a silane coupling agent having an amino group, 2) a water-soluble polymer having an ammonium salt, 3) It is preferable to use a material cationized with at least one cationizing agent selected from aluminum compounds. Hereinafter, cationization of silica will be described.

1) Cationization using a silane coupling agent having an amino group As the silane coupling agent having an amino group, for example, one represented by the following general formula (1) can be used, which is preferable.

  [Wherein, X1 represents an alkoxy group having 1 to 8 carbon atoms or an aryloxy group, and X2 represents a hydrogen atom, an alkyl group having 1 to 18 carbon atoms which may contain a saturated or unsaturated cyclic structure, and 1 carbon atom. To Y represents an alkoxy group having 1 to 8 carbon atoms or an aryloxy group, and Y represents an alkyl group having 1 to 18 carbon atoms which may have a substituent and may have a hetero atom. R represents a primary, secondary or tertiary amino group. n represents an integer of 1 to 3, and m represents 1 or 2. ]

  The alkyl group has 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms. When the carbon number exceeds 18, the reactivity with the inorganic pigment fine particles may decrease. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group. The alkoxy group has 1 to 8 carbon atoms, preferably 1 to 4 carbon atoms. If the carbon number exceeds 8, the reactivity with the inorganic pigment fine particles may be lowered. Examples of the alkoxy group include a methoxy group, an ethoxy group, and a propoxy group, and examples of the aryloxy group include a phenoxy group and a methylphenoxy group.

In general formula (1), Y represents a C1-C18 alkyl group which may have a substituent and may have a hetero atom. The total number of carbon atoms in the alkyl group of Y is preferably 2-8. When the number of carbon atoms exceeds 18, the solubility in water or an alcohol solvent is lowered, and sufficient performance may not be obtained. Examples of the substituent include a halogen atom, a hydroxyl group, an amino group, an ester group, an ether group, and an amide group. Examples of the hetero atom include an oxygen atom, a nitrogen atom, and a sulfur atom. R represents a primary, secondary, or tertiary amino group.
The addition amount of the silane coupling agent is preferably 3 to 30 parts by mass and more preferably 5 to 20 parts by mass with respect to 100 parts by mass of the pigment.

  For example, an amino group-containing silane coupling agent is added to an aqueous dispersion of silica fine particles and heated to covalently bond the silanol groups on the surface of the silica fine particles and the silane coupling agent. ) To make the amino group an ammonium salt to prepare a dispersion of the silica-cation compound aggregate. If desired, it may be pulverized to adjust the average secondary particle size to 500 nm or less.

2) Cationization using a water-soluble polymer having an ammonium salt Water-soluble polymers having an ammonium salt include polyalkyleneamine compounds (for example, polyethylene polyamine, polypropylene polyamine), secondary, tertiary amino groups, or fourth. Acrylic resin having a quaternary ammonium group, polyvinylamine, polyvinylamidine, amidine compound forming a 5-membered ring, dicyan cation resin (for example, dicyandiamide-kilmaldehyde polycondensate), epochlorohydrin-dimethylamine addition polymer, dimethyl diallyl ammonium chloride -SO ₂ copolymer, diallylamine -SO ₂ copolymer, a polymer of dimethyl diallyl ammonium chloride polymers allylamine salt, dialkylaminoethyl (meth) acrylate ammonium Shiokasane Body, acrylamide - aluminum compounds such as diallylamine salt copolymer can be used as appropriate.
These polymers are not preferred if the molecular weight is lower than 5,000 because the ink absorbability is inhibited. In order to improve the fixability of the dye and pigment in the ink and the dispersibility of the silica dispersion, it is more preferable to use 5-membered amidines and dimethyldiallylammonium chloride. The addition amount of the cationic compound is preferably 1 to 30 parts by mass, and more preferably 2 to 15 parts by mass with respect to 100 parts by mass of the pigment.

  For example, an aqueous dispersion of silica fine particles is subjected to a pulverization treatment if necessary to reduce the average secondary particle diameter to a desired value, and a cationic polymer having a molecular weight of 5000 or more is added to the dispersion to -It is good to adjust the average secondary particle diameter to 500 nm or less by forming a cationic compound aggregate and subjecting it to a pulverization treatment.

3) Cationization using an aluminum compound Polyaluminum chloride, polybasic aluminum chloride, polyaluminum acetate, polyaluminum lactate and the like can be used as appropriate, but the fixability of dyes and pigments in the ink, and the silica dispersion In order to improve dispersibility, it is more preferable to use polybasic aluminum chloride. The addition amount of the aluminum compound is preferably 1 to 30 parts by mass and more preferably 2 to 15 parts by mass with respect to 100 parts by mass of the pigment.

  For example, an aqueous dispersion of silica fine particles is optionally pulverized to reduce its average secondary particle size to a desired value, and an aluminum compound is added to the dispersion to obtain a silica-cation compound aggregate. The average secondary particle diameter may be adjusted to 500 nm or less by forming and pulverizing it.

  The use of cationized wet process silica for the outermost surface layer is preferable because the storability of the recorded image is improved. However, such a cationizing agent not only cationizes the silica but also the coating layer as a cationic compound. It is also preferable to contain it in the composition because the storability of the recorded image is improved. When a wet method silica compounded as a cationic compound in the outermost surface layer and cationized is used in combination. It is more preferable because the storage stability is further improved.

Among these, polybasic aluminum chloride is preferably blended since the heat and moisture bleeding of the recorded image is drastically improved. In particular, it is more preferable that polybasic aluminum chloride is contained in the outermost surface coating layer because the effect of heat and moisture bleeding is great. The addition amount of the polybasic aluminum chloride is preferably 1 to 30 parts by mass and more preferably 2 to 15 parts by mass with respect to 100 parts by mass of the pigment.
In addition, a polymer having a primary ammonium salt, a secondary ammonium salt, or a tertiary ammonium salt has a stronger dye ink adsorbability than a polymer having a quaternary ammonium salt structure, and the light fastness of recorded images. It is preferably selected because it exhibits a high effect on ozone resistance and heat and moisture bleeding. The addition amount of the cationic compound is preferably 1 to 30 parts by mass, and more preferably 2 to 15 parts by mass with respect to 100 parts by mass of the pigment.

  The binder used for the outermost surface coating layer is not particularly limited, and water-soluble resins such as polyvinyl alcohol, polyvinylpyrrolidone, casein, soybean protein, synthetic proteins, starch, carboxymethylcellulose, cellulose derivatives such as methylcellulose, Examples include emulsion resins such as vinyl polymers, acrylic polymers, and urethane polymers. Among these, a water-insoluble emulsion resin having a cationic substituent is preferable in order to improve the fixing property and water resistance of the ink. In particular, an acrylic ester emulsion resin having a cationic substituent in the ester group, or an acrylic ester emulsion resin having at least one methacrylic ester as a copolymerization component, a copolymer of an isocyanate and a polyol having a cationic substituent. A urethane emulsion resin in which polymer ionomer resin particles are dispersed is preferably used.

  The outermost surface coating layer particularly preferably has a constitution containing a cationic aqueous emulsion resin as a binder in addition to the wet process silica. In order to increase the gloss of the outermost surface coating layer and the color density of the recorded image, the average particle diameter of the resin-containing particles in the emulsion is preferably 100 nm or less, and more preferably in the range of 10 to 80 nm.

  Further, the coating material of the outermost surface coating layer preferably has a pH of 8 or less and a viscosity of 100 mPa · s or less. If the viscosity is higher than 100 mPa · s, it is difficult to improve the gloss.

  The dry solid content mass ratio between the pigment and the emulsion resin contained in the outermost surface coating layer is not particularly limited as long as it does not inhibit the ink absorbability, but generally the mass ratio is 100/100 to 100 / Is preferably in the range of 3, and in order to improve the balance between ink absorbency and coating strength, it is preferably in the range of 100/30 to 100/5.

In addition to pigments and binders, the outermost surface coating layer of the present invention includes dispersants, thickeners, antifoaming agents, colorants, antistatic agents, preservatives and the like used in general coated paper production. You may contain various adjuvants suitably.
Dry solid coating amount of the outermost surface coating layer is preferably in the range of ^{0.1~3g / m 2, 0.2~1g / m} 2 is more preferable. If the coating amount is too small, the coating film becomes excessively thin and an interference color due to light tends to occur. On the other hand, if the coating amount is excessive, the ink absorption rate may be remarkably reduced.

  Coating equipment for forming the outermost surface coating layer includes various coatings such as blade coaters, air knife coaters, roll coaters, bar coaters, gravure coaters, rod blade coaters, lip coaters, curtain coaters and die coaters. Apparatus. When two or more coating layers are applied, it is preferable to use a method in which the upper layer is applied onto the lower layer while the lower layer is not dried, that is, a wet-on-wet method.

  In order to give high gloss to the surface of the outermost surface coating layer, it is preferable to give the surface a calendar finish or a mirror finish, and a mirror finish is more preferred.

  The calendar finish is a process using a super calendar, a gloss calendar, a soft calendar, a shoe nip calendar, or the like, and can be performed with a nip pressure within a range that does not impair the ink recording suitability of the ink receiving layer. However, in calendar finishing, if the nip pressure is increased to obtain higher gloss, the ink receiving layer tends to lose voids. Therefore, in order to satisfy glossiness and recordability, the mirror finishing method is more effective. This is the preferred method.

  In order to apply a mirror finish to the outermost surface coating layer, it is effective to bring it into contact with the mirror surface and apply heat and pressure, but this is particularly effective while the outermost surface coating layer is in a wet state. A so-called cast finish is preferred in which a heated mirror surface, such as a mirror drum, is pressed and dried, and the mirror surface is copied onto a coating layer. Cast finish includes wet casting method in which the outermost surface coating layer is applied and pressed against the mirror drum, and the outermost surface coating layer is wetted by applying a rewetting liquid after applying and drying the outermost surface coating layer. Mirror surface finishing by known casting methods, such as the rewetting cast method in which the work layer is pressed against the mirror drum, and the gel cast method in which the outermost surface coating layer is gelled with a gelling agent or heat and then pressed against the mirror drum Is possible. Furthermore, at the nip between the mirror drum and the press roll, the outermost surface coating liquid is applied between the inner coating layer surface on the press roll and the mirror drum, and then immediately applied to the mirror drum and dried by mirror finishing. An outermost surface coating layer can be applied. The coating at the nip portion is particularly preferable because the coating layer hardly cracks.

  In order to prevent cracking and increase the drying efficiency, the surface temperature of the heated mirror surface is preferably controlled within the range of 80 to 120 ° C. In order to make it easy to peel the outermost surface coating layer from the crimped mirror surface, a release agent such as stearamide, polyethylene wax, ammonium oleate, etc. may be included in the outermost surface coating layer. Alternatively, it may be applied to a mirror surface. Among these, it is particularly preferable to use a cationic release agent. Although the addition amount of the release agent in the outermost surface coating layer is not particularly limited, it is generally preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the pigment.

  If a non-absorbable support is used, it cannot be produced by a normal casting method, but the outermost surface coating is applied between the inner coating layer surface on the press roll and the mirror drum at the nip between the mirror drum and the press roll. It can be manufactured by applying a liquid and immediately pressing the mirror surface on a mirror surface drum so that the mirror surface is clearly copied onto the coating layer and dried by a drier in a subsequent step. Also, after coating and drying the outermost surface coating layer on the film or mirror drum, it is bonded to the inner coating layer, and the film is peeled off (film transfer method) or transferred from the mirror drum (drum transfer method). Thus, an outermost surface coating layer can be laminated.

  In order to increase the gloss of the outermost surface coating layer, it is preferable that it is calendered or mirror-finished, and in particular, a heated mirror surface while the outermost surface coating layer is in a wet state. For example, it is preferable to use a so-called casting method in which the mirror surface is pressure-bonded to a mirror drum and dried to transfer the mirror surface to the coating layer, particularly a nip cast method in which the mirror drum is applied at the time of pressure contact. In this case, in order to obtain the outermost surface coating layer surface having higher smoothness and higher gloss, the synthetic resin in the latex preferably has a higher glass transition temperature, and a preferable range is 30 ° C to 110 ° C. Of course, other binder substances (for example, water-soluble resin binders) may be used in the binder in addition to the water-insoluble emulsion resin as long as the quality is not impaired.

The peaks in the pore diameter distribution curves of the outermost surface coating layer and the inner coating layer are preferably substantially only at 100 nm or less.
In the pore diameter distribution curves of both coating layers, if the peak of the pore diameter is in a region exceeding 100 nm, the outermost surface coating layer surface and the image recorded on it become insufficient in gloss, and the outermost surface Many cracks occur in the coating layer, the roundness of the dots of the recorded image is lowered, and the uniformity of the recorded image becomes poor. That is, the peak in the pore diameter distribution curve of the outermost surface coating layer and the inner coating layer adjacent thereto is present in the region of 100 nm or less, that is, by making the coating film substantially free of cracks, The outermost surface coating layer having a fine porous structure can be formed to improve the uniformity of the recorded image.

"Undercoating layer constituting the ink receiving layer"
One or more undercoat coating layers may be provided between the support and the inner coating layer for the purpose of improving the adhesion between the support and the inner coating layer or improving the ink absorbability. In particular, when a non-absorbing support is used as the support, it is preferable to form an undercoat coating layer in order to absorb the ink solvent that could not be absorbed by the inner coating layer. Although it does not restrict | limit especially as a material which comprises undercoat coating layer, The material similar to an inner side coating layer can be used. In order to increase the uniformity and color density of the image, it is preferable that the peak in the pore diameter distribution curve is in the region of 100 nm, as in the case of the inner coating layer and the outermost surface coating layer, without cracking. In addition, if a cationic compound is used in the undercoat layer, a part of the dye may be fixed in the undercoat layer and the color density may be lowered. It is preferable to form so that it does not.

"About ink"
The ink for ink jet recording on the ink jet recording material of the present invention includes a dye for forming an image and a liquid medium for dissolving or dispersing the dye as essential components, and various dispersants and surface active agents as necessary. It is prepared by adding an agent, a viscosity modifier, a specific resistance modifier, a pH adjuster, a fungicide, a recording agent dissolution or dispersion stabilizer, and the like.
The dyes or pigments used in the ink include direct dyes, acid dyes, basic dyes, reactive dyes, food dyes, disperse dyes, oil dyes and various colored pigments, each selected from conventional dyes or pigments. can do. The contents of the dye and the pigment in the ink are set depending on the kind of the solvent component of the ink, the characteristics required for the ink, and the like. The content of the dye / pigment in can be set to about 0.1 to 20% by mass.

  Examples of the ink solvent include water and various water-soluble organic solvents, for example, alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, and isobutyl alcohol. , 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, hexylene glycol, diethylene glycol Alkylene glycols having 2 to 6 alkylene groups, amides such as dimethylformamide, ethers such as tetrahydrofuran, glycerin, ethylene glycol Lumpur methyl ether, diethylene glycol methyl (ethyl) ether, such as lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limited at all by the following example. In the examples, “parts” and “%” are based on mass unless otherwise specified.

"Support A: Preparation of paper substrate"
Cationized starch 2 with respect to the absolute dry mass of pulp in a pulp slurry having a concentration of 0.5 mass% (NBKP; freeness 250 ml CSF and LBKP; freeness 280 ml CSF mixed at a mass ratio of 2: 8). 0.0% by mass, alkyl ketene dimer 0.4% by mass, anionized polyacrylamide resin 0.1% by mass, and polyamide polyamine epichlorohydrin resin 0.7% by mass were added and dispersed with sufficient stirring. The pulp slurry having the above composition was made with a long net machine and passed through a drier, a size press, and a machine calendar to produce a base paper having a basis weight of 101 g / m ² and a tenacity of 1.0 g / cm ³ . The size press solution used in the size press step was prepared by mixing carboxyl-modified polyvinyl alcohol and sodium chloride at a mass ratio of 2: 1, adding this to water and dissolving it by heating to a concentration of 5% by mass. A total of 25 ml / m ² of this size press solution was applied to both sides of the paper to produce a paper base with a smoothness (J.TAPPI No. 5-2) of 380 seconds. This was designated as Support A.

“Support B: Production of resin-coated paper”
After performing corona discharge treatment on both sides of the paper substrate, the following surface resin composition mixed and dispersed by a Banbury mixer is applied to the felt surface side of the base paper so that the coating amount is 15 g / m ² , The back side resin composition was applied to the wire surface side of the base paper with a coating amount of 25 g / m ² with a melt extruder having a T-shaped die (melting temperature 320 ° C.), and the felt side was mirrored. The wire side is cooled and solidified with a rough surface cooling roll, and the opacity (JIS P8138) is 93% and the smoothness (J.TAPPI No. 5-2) on the mirror side (the felt side of the base paper) is 26000 seconds. Coated paper was prepared. This was used as the support B, and the mirror side was used as the surface of the support.

(Surface resin composition)
35 parts by mass of long-chain low-density polyethylene resin (density 0.926 g / cm ³ , melt index 20 g / 10 min), 50 parts by mass of low-density polyethylene resin (density 0.919 g / cm ³ , melt index 2 g / 10 min) , 15 parts by mass of anatase-type titanium dioxide (A-220; manufactured by Ishihara Sangyo), 0.1 parts by mass of zinc stearate, 0.03 parts by mass of antioxidant (Irganox 1010; manufactured by Ciba Geigy), ultramarine (Aoguchi Ultramarine No. 2000) Manufactured by Daiichi Kasei Co., Ltd.) and a resin composition for a surface comprising 0.09 parts by mass of a brightening agent (UVITEX OB; manufactured by Ciba Geigy).

(Resin composition for back side)
Back surface comprising 65 parts by mass of high density polyethylene resin (density 0.954 g / cm ³ , melt index 20 g / 10 min) and 35 parts by mass of low density polyethylene resin (density 0.924 g / cm ³ , melt index 4 g / 10 min) A resin composition was prepared.

“Silica fine particle aqueous dispersion A (gelation silica cation)”
After pulverizing and dispersing 100 parts by mass of a commercially available gel silica (produced by Grace Devison, trade name: Silojet P403, average secondary particle size 3 μm) with a sand grinder, a silane coupling agent (γ- ( 2-aminoethyl) aminopropylmethyldimethoxysilane) was added in an amount of 20 parts by mass, and pulverization and dispersion were repeated using a microfluidizer (manufactured by Microfluidics, model number: M110 / EH) until the average secondary particle size reached 400 nm. A 10% by mass aqueous dispersion was prepared.

“Aqueous silica fine particle dispersion A2 (cationized product of silica gel)”
A 10% by mass aqueous dispersion was prepared in the same manner as the silica fine particle aqueous dispersion A, except that the pulverization and dispersion were repeated until the average secondary particle diameter reached 600 nm.

"Silica fine particle aqueous dispersion B (cationized silica gel)"
After 100 parts by mass of commercially available silica gel (Grace Devison, trade name: Silojet P403, average secondary particle size 3 μm) was pulverized and dispersed with a sand grinder, 30 parts by mass of polybasic aluminum chloride was added, Using a tizer (Microfluidics, model number: M110 / EH), pulverization and dispersion were repeated until the average secondary particle size reached 300 nm to prepare a 10% by mass aqueous dispersion.

"Silica fine particle aqueous dispersion C (silica cationized product obtained by condensing activated silicic acid)"
(A) Preparation of Active Silicic Acid Aqueous Solution Distilled water is added to a sodium silicate solution (trade name: No. 3 sodium silicate, manufactured by Tokuyama Co., Ltd.) having a SiO ₂ concentration of 30% by mass and a SiO ₂ / Na ₂ O molar ratio of 3.1. By mixing, a dilute sodium silicate aqueous solution having a SiO ₂ concentration of 4.0% by mass 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 SiO ₂ concentration in the obtained active silicic acid aqueous solution was 4.0% by mass, and the pH was 2.9. Further, Na ₂ O in terms of concentration was 0.1% by mass or less.
(B) Preparation of seed solution 500 g of distilled water was heated to 100 ° C. in a 5 liter glass reaction vessel equipped with a refluxer, a stirrer, and a thermometer. 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.
(C) Preparation of Silica Fine Particle Dispersion In the glass reaction vessel described above, 0.015 mol of ammonia was added to 950 g of the seed solution and stabilized, 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% by mass aqueous dispersion.
(D) Preparation of cationic silica fine particles Cationic compound (trade name: SC-700, molecular weight: 300,000) having a 5-membered ring amidine structure in 100 parts by mass of the 10% by mass silica water dispersion 10 mass Part was added and pulverized and dispersed with a high-speed collision type homogenizer until the average secondary particle size reached 150 nm to prepare a 10% by mass aqueous dispersion.

"Silica fine particle aqueous dispersion D (cationized product of vapor phase silica)"
Gas phase method silica having an average particle diameter of 1.0 μm (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil A300, average primary particle diameter: about 8 nm) was dispersed by a homomixer, and then the average secondary particle diameter was 800 nm. A 10% by mass aqueous dispersion was prepared by pulverizing and dispersing with a high-speed collision type homogenizer.
10 parts by mass 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 100 parts by mass of the 10% by mass aqueous dispersion, and a high-speed flow collision type homogenizer is added. And a 10% aqueous dispersion having an average secondary particle diameter of 150 nm was prepared.

"Silica fine particle aqueous dispersion D2 (cationized product of vapor phase silica)"
Gas phase method silica having an average particle diameter of 1.0 μm (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil A300, average primary particle diameter: about 8 nm) was dispersed by a homomixer, and then the average secondary particle diameter was 800 nm. A 10% by mass aqueous dispersion was prepared by pulverizing and dispersing with a high-speed collision type homogenizer.
10 parts by mass 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 100 parts by mass of the 10% by mass aqueous dispersion, and a high-speed flow collision type homogenizer is added. And 10% aqueous dispersion having an average secondary particle diameter of 900 nm was prepared.

"Silica fine particle aqueous dispersion D3 (cationized product of vapor phase silica)"
Gas phase method silica having an average particle diameter of 1.0 μm (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil A300, average primary particle diameter: about 8 nm) was dispersed by a homomixer, and then the average secondary particle diameter was 800 nm. A 10% by mass aqueous dispersion was prepared by pulverizing and dispersing with a high-speed collision type homogenizer.
10 parts by mass 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 100 parts by mass of the 10% by mass aqueous dispersion, and a high-speed flow collision type homogenizer is added. And a 10% aqueous dispersion having an average secondary particle size of 600 nm was prepared.

"Silica fine particle aqueous dispersion E (anionic wet gel silica)"
A step of pulverizing and dispersing 100 parts by mass of a commercially available gel silica (produced by Grace Devison, trade name: Silojet P403, average secondary particle size 3 μm) in water with a sand grinder, followed by a microfluidizer (produced by Microfluidics, model number) : M110 / EH) was repeated in combination with the step of pulverizing and dispersing in water to prepare a 20% by mass aqueous dispersion having an average secondary particle size of 350 nm.

[Example 1]

On the surface of the support B, the following coating solution 1 for the inner coating layer is applied using a bar so that the dry coating amount is 25 g / m ² , and then immediately irradiated with an electron beam in a nitrogen gas environment. An electron beam with an accelerating voltage of 175 kV and an irradiation dose of 50 kGy was irradiated by an apparatus (Electro Curtain manufactured by ESI). The coated surface after irradiation was a jelly-like solid, and was hydrogelled. Subsequently, the hydrogelled coating liquid layer was dried to form an inner coating layer.
Next, on the inner coating layer, the following outermost surface coating layer coating solution 1 is applied using a bar so that the dry coating amount is 0.5 g / m ² and dried. A coating layer was formed to produce an ink jet recording material.

(Coating solution 1 for the inner coating layer)
100 parts by mass (solid content) of silica fine particle aqueous dispersion D (solid phase gas phase method) and polyvinyl alcohol (made by Kuraray Co., Ltd., trade name: PVA-235, polymerization degree 3500, saponification degree 88.5%) as a binder ) 18 parts by mass and 0.05 parts by mass of a dispersant (manufactured by Toa Gosei Co., Ltd., trade name: Aron SD-10) were mixed in water to prepare a coating solution (concentration: 15% by mass).

(Coating liquid 1 for outermost surface coating layer)
In 100 parts by mass (solid content) of silica fine particle aqueous dispersion B (gelation silica cation), 15 parts by mass of an emulsion type acrylic resin latex (average particle size: 60 nm, Tg = 100 ° C.) as a binder, a release agent ( A coating liquid (concentration: 10% by mass) was prepared by mixing 5 parts by mass of ammonium oleate in water. The viscosity of this coating liquid was 40 mPa · s.

[Example 2]
On the surface of the support B, the following coating solution 1 for the undercoat coating layer is applied using a Mayer bar so that the dry coating amount is 16 g / m ² , and this coating solution layer is blown at 120 ° C. An undercoat coating layer was formed by drying with a dryer.
Next, the coating liquid 1 for the inner coating layer described in Example 1 was further dried on the undercoat coating layer so that the dry coating amount of the 2.0% borax aqueous solution was 0.15 g / m ^2. Coating was performed using a bar under the condition of Wet on Wet so that the coating amount was 10 g / m ^{2. After} the coating liquid layer was gelled, the inner coating layer was dried by a 120 ° C. blower dryer. Formed.
On this inner coating layer, the outermost surface layer coating solution 2 described in Example 1 is coated and dried using a bar so that the coating amount is 0.5 g / m ² , and outermost surface coating is performed. Layers were formed to produce an ink jet recording body having a three-layer ink receiving layer.

(Coating liquid 1 for undercoat coating layer)
Silica fine particle water dispersion E (anionic gel method silica) 100 parts (solid content), polyvinyl alcohol (Kuraray Co., Ltd., trade name: PVA-135H, polymerization degree 3500, saponification degree 99% or more) as a binder 18 parts by mass Then, 0.05 part by mass of a dispersant (manufactured by Toa Gosei Co., Ltd., trade name: Aron SD-10) was mixed in water to prepare a coating solution (concentration: 15% by mass).

(Coating liquid 2 for outermost surface coating layer)
In 100 parts by weight (solid content) of silica fine particle aqueous dispersion A (gel method silica cation), 15 parts by weight of an emulsion type acrylic resin latex (average particle size: 30 nm, Tg = 50 ° C.) as a binder, a release agent ( 5 parts by weight of ammonium oleate) was mixed in water to prepare a 5% by weight coating solution. The viscosity of this coating liquid was 30 mPa · s.

[Comparative Example 1]
Instead of the silica fine particle aqueous dispersion D (average secondary particle size: 150 nm) contained in the coating liquid 1 for the inner coating layer of Example 2, a silica fine particle aqueous dispersion D2 (average secondary particle size: 900 nm) was used. An ink jet recording material was produced in the same manner as in Example 2 except that the adjustment was made using the above method.

[Comparative Example 2]
Instead of the silica fine particle aqueous dispersion A (average secondary particle size: 400 nm) contained in the outermost surface coating layer coating solution 2 of Example 2, the silica fine particle aqueous dispersion A1 (average secondary particle size: 600 nm). An ink jet recording material was prepared in the same manner as in Example 2 except that the above was adjusted using

[Comparative Example 3]
Instead of silica fine particle water dispersion D (cationized product of gas phase method silica) contained in coating solution 1 for inner coating layer of Example 2, silica fine particle aqueous dispersion A (cationized product of gel method silica) was used. An ink jet recording material was produced in the same manner as in Example 2 except that the adjustment was performed.

[Comparative Example 4]
Instead of silica fine particles A (cationized product of gel method silica) contained in coating solution 2 for outermost surface coating layer of Example 2, silica fine particle aqueous dispersion D (cationized product of vapor phase method silica) was used. An ink jet recording material was produced in the same manner as in Example 2 except for the adjustment.

Example 3
In the same manner as in Example 1, an inner coating layer was formed.
Next, at the nip portion between the mirror drum and the press roll, the outermost surface coating solution 1 was applied between the inner coating layer surface on the press roll and the mirror drum, and immediately pressed once onto the mirror drum having a surface temperature of 95 ° C. Then, it dried with the dryer and formed the outermost surface coating layer, and produced the inkjet recording body. The dry coating amount was 0.5 g / m ² .

Example 4
In the same manner as in Example 1, an inner coating layer was formed.
Next, at the nip portion between the mirror drum and the press roll, the outermost surface coating liquid 2 was applied between the inner coating layer surface on the press roll and the mirror drum, and immediately contacted with the mirror drum having a surface temperature of 95 ° C. Then, it dried with the dryer and formed the outermost surface coating layer, and produced the inkjet recording body. The dry coating amount was 0.5 g / m ² .

Example 5
In the same manner as in Example 2, an undercoat coating layer and an inner coating layer were formed.
Next, at the nip between the mirror drum and the press roll, the outermost surface coating layer coating solution 2 is applied between the inner coating layer surface on the press roll and the mirror drum, and immediately applied to the mirror drum having a surface temperature of 95 ° C. After press-contacting once, it was dried with a dryer to form an outermost surface coating layer, and an ink jet recording material was produced. The dry coating amount was 0.5 g / m ² .

Example 6
An ink jet recording material was produced in the same manner as in Example 5 except that the following outermost surface coating layer coating solution 3 was used instead of the outermost surface coating layer coating solution 2 of Example 5.

(Coating liquid 3 for outermost surface coating layer)
Silica fine particle aqueous dispersion C (cationized product of wet process silica) 100 parts by mass (solid content), emulsion-type cation-modified urethane latex (average particle size: 30 nm, Tg = 80 ° C.) 20 parts by mass, release agent ( 5 parts by weight of stearamide) was mixed with water to prepare a 5% by weight aqueous solution. The viscosity of this aqueous dispersion was 20 mPa · s.

Example 7
Instead of the silica fine particle aqueous dispersion D (average secondary particle size: 150 nm) contained in the coating liquid 1 for the inner coating layer of Example 6, a silica fine particle aqueous dispersion D3 (average secondary particle size: 600 nm) was used. An ink jet recording material was produced in the same manner as in Example 6 except that the adjustment was made using the above method.

Example 8
Instead of silica fine particle aqueous dispersion A (cationized product of gel method silica) contained in coating solution 2 for outermost surface coating layer of Example 5, silica fine particle aqueous dispersion E (anionic wet gel method silica) was used. An ink jet recording material was produced in the same manner as in Example 5 except that the adjustment was performed.

Example 9
Instead of the emulsion type acrylic resin latex (average particle size: 30 nm, Tg = 50 ° C.) contained in the outermost surface coating layer coating liquid 2 of Example 5, an emulsion type acrylic resin latex (average particle size: 120 nm, An ink jet recording material was produced in the same manner as in Example 5 except that the temperature was adjusted using Tg = 50 ° C.).

Example 10
In the formulation of the coating liquid 2 for the outermost surface coating layer of Example 5, the water content was reduced and a coating liquid having a concentration of 15% by mass was prepared. The viscosity of this coating liquid was 120 mPa · s. An ink jet recording material was produced in the same manner as in Example 5 except that this coating solution was used.

Example 11
In place of the silica fine particle aqueous dispersion A (cationized product of gel method silica) contained in the coating solution 2 for the outermost surface coating layer of Example 5, the silica fine particle aqueous dispersion A (cationized product of gel method silica) An ink jet recording material was prepared in the same manner as in Example 5 except that the mixture was prepared by mixing 30/70 with cationic colloidal silica (manufactured by Nissan Chemical Co., Ltd., trade name: ST-AKL, primary particles: 50 nm). Produced.

Example 12
In place of the silica fine particle aqueous dispersion A (cationized product of gel method silica) contained in the coating solution 2 for the outermost surface coating layer of Example 5, the silica fine particle aqueous dispersion A (cationized product of gel method silica) An ink jet recording material was prepared in the same manner as in Example 5 except that the mixture was prepared by mixing 50/50 with cationic colloidal silica (manufactured by Nissan Chemical Co., Ltd., trade name: ST-AKL, primary particles: 50 nm). Produced.

Example 13
An ink jet recording material was produced in the same manner as in Example 5 except that the support in Example 5 was changed from the support B (resin-coated paper) to the support A (paper substrate).

[Comparative Example 5]
Instead of silica fine particle aqueous dispersion A (cationized product of wet gel method silica) contained in coating solution 2 for outermost surface coating layer of Example 5, silica fine particle aqueous dispersion D (cationized product of vapor phase method silica) ) And silica fine particle aqueous dispersion A (wet gel silica cation) instead of silica fine particle water dispersion D (vapor phase silica cation) contained in inner coating layer coating liquid 1 An ink jet recording material was produced in the same manner as in Example 5 except that.

[Comparative Example 6]
Cationic colloidal silica (manufactured by Nissan Chemical Co., Ltd., trade name: ST) instead of the silica fine particle aqueous dispersion A (cationized product of wet gel silica) contained in the outermost surface coating layer coating liquid 2 of Example 5 An ink jet recording material was produced in the same manner as in Example 5 except that -AKL, primary particles: 50 nm) was used.

[Comparative Example 7]
On the surface of the support B, the inner coating layer coating liquid 2 having the following composition was coated and dried using a bar so that the dry coating amount was 8 g / m ² to form an inner coating layer. . On this inner coating layer, the outermost surface coating layer coating solution 4 having the following composition is coated using a bar so that the dry coating amount is 1 g / m ² and dried to be the outermost surface coating. A layer was formed to prepare an ink jet recording material.

(Coating solution 2 for the inner coating layer)
100 parts by mass of amorphous silica (manufactured by Tokuyama, trade name: Fine Seal X-37B), 30 parts by mass of polyvinyl alcohol (manufactured by Kuraray, PVA-117, polymerization degree 1700, saponification degree 98.5%), single Dispersion colloidal silica (manufactured by Nissan Chemical Industries, trade name: ST-O, average particle size: 0.015 μm) 30 parts by mass and cationic dye fixing agent (manufactured by Sumitomo Chemical Co., trade name: Sumirez Resin 1001) 20 masses Were mixed in water to prepare a 15% by mass aqueous dispersion.

(Coating liquid 4 for outermost surface coating layer)
100 parts by mass of polystyrene organic particles having an average particle diameter of 0.2 μm (trade name: L8999, manufactured by Asahi Kasei Kogyo Co., Ltd.) and styrene / butadiene latex (trade name: 0693, manufactured by Nippon Synthetic Rubber Co., Ltd.) as the binder : 0.135 μm) A 25 mass% aqueous dispersion in which 30 parts by mass and 2 parts by mass of a release agent (potassium oleate) were mixed in water was prepared.

"Evaluation methods"
About the manufactured inkjet recording material, the peak on the distribution curve of the pore diameter of the outermost surface coating layer, the ink absorbency, the image uniformity, the print density, the glossiness, and the pigment ink suitability are measured by the methods shown below, evaluated. The results are shown in Table 1.
In addition, the ink-jet printer (trademark: PM-4000PX, printing mode: MC glossy paper fast mode) was used for evaluation of the pigment ink suitability. Other evaluations were performed using an inkjet printer (manufactured by EPSON, trademark: PM-950C, print mode: PM photographic paper clean mode).

[Peak on pore diameter distribution curve]
A method for measuring a peak in the pore diameter distribution curve defined in the present invention will be described. In the measurement method, in order to avoid the influence of the base material, the coating layer was peeled off from the base material with a cutter or the like and subjected to measurement. The pore diameter distribution was determined by a mercury intrusion method using a Micrometrics Posizer 9320 (Motel, manufactured by Shimadzu Corporation) as a measuring instrument. 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 represents the pore radius (2R = pore diameter), γ represents the surface tension of mercury, θ represents the contact angle, and P represents the pressure.
The surface tension of mercury is 48.2536 μN / cm (482.536 dyn / cm), the contact angle used is 130 °, the low pressure part of mercury pressure (0 to about 0.207 MPa (0 to 30 psia), the measurement pores Radius: 180-3 μm) and high pressure part (0 to about 207 MPa (0-30000 psia), measurement pore radius: 3-0.003 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. Usually, one to several peaks are observed in the pore diameter distribution curve of the coating layer.

[Ink absorbability (print spots)]
A green recording medium was solid-printed on the recorded recording medium, and whether or not there were spots in the solid-printed image 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 the surface. It becomes noticeable when it becomes late.
A: No printed spots are seen.
○: There are some printed spots, but there is no practical problem.
(Triangle | delta): Print spot is seen and practicability is low.
X: Many printing spots.

[Image uniformity (dot roundness)]
An ISO-400 image (“high-definition color digital standard image data ISO / JIS-SCID”, p13, image name: fruit basket) is printed on the sample recording medium, and the uniformity (background) of the image is visually observed. And evaluated in the following two stages. If the dot is a perfect circle, the portion where the dot and many dots overlap becomes extremely uniform, but the uniformity of the image decreases as the roundness of the dot decreases.
○: The image is uniform and spots are not visible (dots are close to a perfect circle, and no jagged edges are seen at the edges).
X: The image is non-uniform and spots are seen (dots have low roundness and jagged edges).

[Color density of recorded image]
Each color ink and the heavy color portion were solid-printed, and the color density was measured with a Macbeth reflection densitometer (model: Macbeth RD-920, manufactured by Macbeth Co.).
A: The color density of each color is high and the recorded image is vivid.
○: No decrease in color density is observed, but the recorded image is slightly less vivid.
X: The color density is lowered and the recorded image feels sunk.

[Glossy]
An ISO-400 image (“high-definition color digital standard image data ISO / JIS-SCID”, p13, image name: fruit basket) is printed on the sample recording medium, and the image is printed on the surface of the recording medium. It visually observed from the angle which inclined, and evaluated in the following three steps.
(Double-circle): It has the same glossiness as a silver salt photograph.
○: Slightly inferior to silver salt photograph, but has sufficient gloss.
Δ: Gloss equivalent to or lower than that of a conventional glossy ink jet recording material.
X: There is almost no gloss and it is a level close to a mat.

[Pigment ink suitability]
The test recording medium was solid-printed with black pigment ink, and the uniformity of the solid-printed portion and the spur trace formed by the transport roll in the recording process were evaluated in the following four stages.
A: Printed spots and spurs are not seen at all.
○: There are some printed spots and spur traces, but there are no practical problems.
(Triangle | delta): Print spots and a spur trace are seen, and its practicality is low.
X: There are many printed spots and spur marks.

The ink jet recording material obtained in the present invention has good gloss and ink absorbability, the ink receiving layer (particularly, the first inner coating layer and the outermost surface coating layer) is not cracked, and the dots of the recorded image have a perfect circle. Since the degree is high, the quality of the recorded image is very good. In particular, the pigment ink is also useful as a recording medium for both dye and pigment ink because a high image equivalent to a silver salt photograph can be obtained, which is equivalent to the dye ink.

Claims (10)

In an ink jet recording body in which an ink receiving layer is laminated on a support, at least of an outermost surface coating layer and an inner coating layer disposed between the outermost surface coating layer and the support. 2 layers, the outermost surface coating layer contains wet method silica having an average secondary particle diameter of 500 nm or less as a main component, and the inner coating layer adjacent to the outermost surface coating layer is an average secondary particle An ink jet recording material comprising gas phase method silica having a diameter of 700 nm or less. The wet process silica contained in the outermost surface coating layer is cationized by at least one cationizing agent selected from a silane coupling agent having an amino group, a water-soluble polymer compound having an ammonium salt, and an aluminum compound. 2. The ink jet recording material according to claim 1, which is silica. 3. The ink jet recording material according to claim 1, wherein the wet process silica contained in the outermost surface coating layer is a colloidal silica or gel colloid obtained by condensing active silicic acid. The ink jet recording body according to any one of claims 1 to 3, wherein the outermost surface coating layer is a layer obtained by applying a coating liquid containing a cationic aqueous emulsion resin. The ink jet recording material according to claim 4, wherein the average particle diameter of the emulsion resin is 100 nm or less. The inkjet recording material according to any one of claims 1 to 5, wherein the coating material of the outermost surface coating layer has a pH of 8 or less and a viscosity of 100 mPa · s or less. The peak in the pore diameter distribution curve of the outermost surface coating layer and the inner coating layer adjacent to the outermost surface coating layer is substantially only at 100 nm or less. Inkjet recording material. The vapor-phase process silica contained in the inner coating layer is cationized by at least one cationizing agent selected from a silane coupling agent having an amino group, a water-soluble polymer compound having an ammonium salt, and an aluminum compound. Item 8. The ink jet recording material according to any one of Items 1 to 7. The ink jet recording material according to any one of claims 1 to 8, wherein the support is a non-absorbing support. After the inner coating layer is applied, the outermost surface coating layer is applied while the outermost surface coating layer is in a wet state after the coating layer has come to exhibit a reduced rate of drying. The ink jet recording material according to claim 1, wherein the ink jet recording material is obtained by press-contacting to a heated mirror drum and then drying.