JP2003159862A - Inkjet recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an inkjet recording material with excellent gloss, ink absorbing properties and resistance to scuffing and a uniform coated face. <P>SOLUTION: In the inkjet recording material manufactured by applying a coating liquid for at least one ink receiving layer mainly containing an inorganic particle and a coating liquid for a layer containing a colloidal silica and a cationic compound on a substrate in this order, the inkjet recording material is characterized by pH of the coating liquid for the layer containing the colloidal silica being 3.3-6.0. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet recording material, and more particularly to an inkjet recording material excellent in gloss, ink absorbency and scratch resistance.

[0002]

2. Description of the Related Art As a recording material used in an ink jet recording system, a porous material made of a pigment such as amorphous silica and a water-soluble binder such as polyvinyl alcohol is provided on a support called ordinary paper or ink jet recording paper. A recording material provided with the ink receiving layer is known.

For example, JP-A-55-51583 and JP-A-5-51583.
No. 6-157, No. 57-107879, No. 57-10.
No. 7880, No. 59-230787, No. 62-160.
No. 277, No. 62-184879, No. 62-1833.
No. 82 and No. 64-11877, there are proposed recording materials obtained by coating a paper support with a silicon-containing pigment such as silica together with an aqueous binder.

Further, Japanese Patent Publication No. 3-56552 and Japanese Patent Laid-Open No. Hei 2
-188287, 10-81064, 10
-119423, 10-175365, 10
-203006, 10-217601, 11
-20300, Doppei 11-20306, Doppei 11-
Japanese Patent No. 344881 and the like disclose recording materials using synthetic silica fine particles by a vapor phase method (hereinafter referred to as vapor phase method silica). Also, JP-A-62-174183
JP-A-2-276670 and JP-A-5-32037.
JP-A-6-199034 and the like disclose recording materials using alumina and alumina hydrate.

The above-mentioned vapor-phase process silica, alumina or alumina hydrate has an average primary particle size of several nm.
It is an ultrafine particle of ˜several tens of nanometers, and is characterized by high gloss and high ink absorption. However, on the other hand, there are problems that scratches are likely to occur on the surface of the ink receiving layer because they are ultrafine particles, and that scratches are likely to stand out because of the high gloss.

On the other hand, as a support for an ink jet recording material, paper has been generally used, and the paper itself has a role as an ink absorbing layer. In recent years, as photo-like recording sheets have been demanded, recording sheets using a paper support have problems such as gloss, texture, water resistance, cockling (wrinkles or waviness) after printing, and are treated with water resistance. Further, a paper support such as a resin-laminated paper (polyolefin resin-coated paper) in which a polyolefin resin such as polyethylene is laminated on both surfaces of the paper, a plastic film or the like has come to be used. However,
These water-resistant supports have a high smoothness of the surface provided with an ink receiving layer unlike a paper support, and thus when scratched on the back surface, scratches easily occur on the ink receiving layer surface due to rubbing, and There is a problem that double feeding is likely to occur during printing. Further, since the water-resistant support itself has no ink absorbing ability, it is necessary to increase the ink absorbing capacity of the ink receiving layer, and for that purpose, it is necessary to apply a thick inorganic fine particle layer having a high porosity. In order to increase the porosity, it is necessary to reduce the ratio of the organic binder to the inorganic fine particles, and the decrease in the amount of the organic binder makes the film of the ink receiving layer brittle, and scratches are more likely to occur. This phenomenon is particularly remarkable when ultrafine particles having an average primary particle diameter of 50 nm or less, which are vapor-phase process silica, alumina, and alumina hydrate are used.

As a technique for solving the above problem, for example, it has been proposed to provide a layer containing colloidal silica as an upper layer. For example, JP-A-6-18313
1, JP-A-6-183134, JP-A-7-1011.
42, JP-A-9-183267, and JP-A-10-71.
762, JP-A-10-166715, JP-A-2000
-33769, JP-A-2000-37944, 20
00-108505, 2000-280609,
It is described in JP 2001-10212 A and the like.
However, simply providing the colloidal silica layer on the upper layer could not sufficiently satisfy gloss, ink absorption and scratch resistance at the same time.

Further, as can be seen from the above-mentioned Japanese Patent Laid-Open Publication, as a conventional general manufacturing method, a lower ink receiving layer is applied and dried, and then an upper colloidal silica layer is applied and dried. The coating method was adopted.
It has been confirmed that the constitution of an ink receiving layer having a relatively large film thickness and a colloidal silica layer having a relatively small film thickness is preferable in order to enhance ink absorbency, which is one of the objects of the present invention. In the case of the configuration, the conventional manufacturing method described above,
That is, it was found that sufficient gloss and scratch resistance cannot be obtained by a method of coating a colloidal silica layer on an ink receiving layer which has been previously coated and dried, and then drying. Further, the method of successively coating a relatively thin colloidal silica layer on the ink receiving layer has a problem that it is difficult to obtain a uniform coated surface.

[0009]

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide an ink jet recording material which has excellent gloss, ink absorption and scratch resistance and has a uniform coated surface.

[0010]

The above object of the present invention is to provide a coating liquid for an ink receiving layer mainly containing at least one layer of inorganic fine particles on a support, and a layer containing colloidal silica and a cationic compound. In the ink jet recording material obtained by applying the coating liquid of 1. in this order, the coating liquid of the layer containing colloidal silica has a pH of 3.3 to 6.0, which is basically achieved by the ink jet recording material. Was done.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The inkjet recording material of the present invention has at least one ink receiving layer mainly containing inorganic fine particles. Here, containing the inorganic fine particles as a main component means that the content of the inorganic fine particles is 50% by mass or more, preferably 60% by mass, and particularly preferably 65% based on the total solid content of the ink receiving layer.
It means that the content is at least mass%. In the present invention,
The total amount of the inorganic fine particles contained in the ink receiving layer (when there are two or more ink receiving layers mainly containing the inorganic fine particles, it means the total amount) is 10 to 50 g.
/ M ² is preferable, and the range of 15 to 40 g / m ² is more preferable.

In the present invention, the type of the inorganic fine particles used is not particularly limited, but vapor phase silica, alumina, or alumina hydrate is preferable in terms of gloss and ink absorbability. These inorganic fine particles may be used alone or in combination. Further, in the present invention, the ink receiving layer may have a single-layer structure or a multi-layer structure.
In the case of a one-layer structure, for example, there is a mode in which one type of fumed silica, alumina and alumina hydrate is contained alone, or a mode in which a plurality of types are used in combination, and any of them can be adopted. When the ink receiving layer has a multi-layer structure,
For example, there are a mode in which a plurality of layers are composed of only one type of vapor phase method silica, alumina and alumina hydrate, a mode in which different types are contained in separate layers, and the like. Examples thereof include a two-layer structure of a containing layer and a layer containing alumina or alumina hydrate, or a mode in which vapor phase silica having different particle diameters is contained in separate layers.

The vapor-phase method silica preferably used in the present invention is also called a dry method as opposed to a wet method, and is generally produced by a flame hydrolysis method. Specifically, a method of burning silicon tetrachloride with hydrogen and oxygen is generally known, but instead of silicon tetrachloride, silanes such as methyltrichlorosilane and trichlorosilane may be used alone or in the form of silicon tetrachloride. It can be used as a mixture with.
Vapor phase silica is commercially available as Aerosil from Nippon Aerosil Co., Ltd. and QS type from Tokuyama Corp., and can be obtained.

The average primary particle diameter of the vapor phase silica is 5 to 5
0 nm is preferable, and in order to obtain higher gloss,
20 nm and BET specific surface area of 90-400
It is preferable to use m ² / g. BE referred to in the present invention
The T method is one of the powder surface area measurement methods by the vapor phase adsorption method, and is a method of obtaining the total surface area of 1 g of a sample, that is, the specific surface area, from the adsorption isotherm. Nitrogen gas is often used as the adsorbed gas, and the most commonly used method is to measure the adsorbed amount from the change in pressure or volume of the adsorbed gas. The most prominent of the isotherms of multimolecular adsorption is the Brunauer, Emmett, and Teller equation, which is BET.
It is called a formula and is widely used to determine the surface area. The surface area is obtained by determining the adsorption amount based on the BET formula and multiplying the area occupied by one adsorbed molecule on the surface.

As the alumina used in the present invention, γ-alumina which is a γ type crystal of aluminum oxide is preferable, and δ group crystal is particularly preferable. With γ-alumina, the primary particles can be reduced to about 10 nm, but normally, secondary particle crystals of several thousands to tens of thousands nm are treated with ultrasonic waves, a high-pressure homogenizer, a facing collision type jet crusher, etc. Those crushed to about 300 nm can be preferably used.

Alumina hydrate used in the present invention is A
It is represented by a constitutive formula of l ₂ O ₃ · nH ₂ O (n = 1 to 3).
When n is 1, it represents an alumina hydrate having a boehmite structure, and when n is more than 1 and less than 3, it is an alumina hydrate having a pseudo-boehmite structure. It can be obtained by a known production method such as hydrolysis of aluminum alkoxide such as aluminum isopropoxide, neutralization of aluminum salt with alkali, and hydrolysis of aluminate.

The average particle size of the primary particles of alumina hydrate is
5 to 50 nm is preferable, and in order to obtain higher gloss, it is preferable to use tabular grains having an average aspect ratio (ratio of average particle diameter to average thickness) of 2 or more and 5 to 20 nm.

In the present invention, the ink receiving layer preferably contains an organic binder in order to maintain the properties as a film. As the organic binder, various water-soluble polymers or polymer latices are preferably used. Examples of the water-soluble polymer include polyvinyl alcohol, polyethylene glycol, starch, dextrin,
Carboxymethyl cellulose, polyvinylpyrrolidone,
Polyacrylic acid ester type or the like and derivatives thereof are used, but a particularly preferable organic binder is completely or partially saponified polyvinyl alcohol or cation-modified polyvinyl alcohol.

Among the polyvinyl alcohols, those partially or completely saponified with a saponification degree of 80% or more are particularly preferable. Polyvinyl alcohol having an average degree of polymerization of 500 to 5000 is preferable. In addition, examples of the cation-modified polyvinyl alcohol include, for example, JP-A 61-1048.
As described in No. 3, it is a polyvinyl alcohol having a primary to tertiary amino group and a quaternary ammonium group in the main chain or side chain of polyvinyl alcohol.

Examples of the polymer latex used as the organic binder include, for example, acrylic latex, alkyl group, aryl group, aralkyl group,
Acrylic esters or methacrylic esters such as hydroxyalkyl groups, acrylonitrile, acrylamide, homopolymers or copolymers of acrylic acid and methacrylic acid, or the above monomers, and styrenesulfonic acid, vinylsulfonic acid, itaconic acid, Maleic acid,
Examples thereof include fumaric acid, maleic anhydride, vinyl isocyanate, allyl isocyanate, vinyl methyl ether, vinyl acetate, styrene, and copolymers with divinylbenzene. As the olefin latex, a polymer composed of a copolymer of a vinyl monomer and a diolefin is preferable, and as the vinyl monomer, styrene, acrylonitrile, methacrylonitrile, methyl acrylate, methyl methacrylate, vinyl acetate, etc. are preferably used.
Examples of diolefins include butadiene, isoprene and chloroprene.

In the ink receiving layer of the present invention, it is preferable to use the organic binder in an amount of 5 to 35% by mass, particularly preferably 10 to 30% by mass based on the inorganic fine particles.

In the present invention, when the ink receiving layer contains fumed silica as the inorganic fine particles, it is preferable to additionally contain a cationic compound. By containing a cationic compound in the ink receiving layer, it is possible to prevent the ink receiving layer from cracking and improve the water resistance. Further, by providing a layer containing colloidal silica and a cationic compound on the ink receiving layer containing the cationic compound, scratch resistance, water resistance, and ink absorbability are further improved. Aggregation at the interface is prevented, and as a result, uneven coating and uneven gloss are eliminated. When alumina or alumina hydrate is contained as the inorganic fine particles in the ink receiving layer, sufficient cracking and water resistance can be obtained without necessarily using the cationic compound together.

As the cationic compound used in the present invention, a cationic polymer or a water-soluble polyvalent metal compound is preferably used. These cationic compounds and water-soluble polyvalent metal compounds can be used alone or in combination.

Examples of the cationic polymer used in the present invention include water-soluble cationic polymers having a quaternary ammonium group, a phosphonium group, or an acid addition product of a primary to tertiary amine. For example, polyethyleneimine,
Polydialkyldiallylamine, polyallylamine, alkylamine epichlorohydrin polycondensate, JP-A-59
-20696, 59-33176, 59-33
177, 59-155088 and 60-1138.
No. 9, No. 60-49990, No. 60-83882,
60-109894, 62-198493, 63-49478, 63-115780, 63.
-280681, JP-A-1-40371, 6-2
No. 34268, No. 7-125411, No. 10-193.
The cationic polymers described in Japanese Patent No. 776 and the like can be mentioned. The weight average molecular weight of the cationic polymer used in the present invention is preferably 100,000 or less, more preferably 5
It is less than 10,000 and the lower limit is about 2,000.

The amount of these cationic polymers used is preferably in the range of 1 to 10% by mass with respect to the inorganic fine particles.

As the polyvalent metal in the water-soluble polyvalent metal compound, calcium, barium, manganese, copper,
Examples thereof include cobalt, nickel, aluminum, iron, zinc, zirconium, titanium, chromium, magnesium, tungsten and molybdenum, which can be used as water-soluble salts of these metals. Specifically, for example, calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium sulfate, barium phosphate,
Manganese chloride, manganese acetate, manganese formate dihydrate,
Manganese ammonium sulfate hexahydrate, cupric chloride, ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate , Nickel acetate tetrahydrate, nickel ammonium sulfate hexahydrate, nickel amido sulfate tetrahydrate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride,
Aluminum nitrate nonahydrate, aluminum chloride hexahydrate, ferrous bromide, ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, zinc bromide, zinc chloride, zinc nitrate hexahydrate Hydrate, zinc sulfate, zirconium acetate, zirconium nitrate,
Basic zirconium carbonate, zirconium hydroxide, zirconium carbonate ammonium, zirconium carbonate potassium, zirconium sulfate, zirconium fluoride, zirconium chloride, zirconium chloride octahydrate, zirconium oxychloride, hydroxyzirconium chloride, titanium chloride,
Titanium sulfate, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate, sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 1
2 Tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate and the like can be mentioned. Among these, water-soluble salts of aluminum or Group IVa elements (zirconium, titanium) of the periodic table are particularly preferable. In the present invention, the term “water-soluble” means that it is dissolved in water at 1% by mass or more under normal temperature and pressure.

As the water-soluble aluminum compound other than the above, a basic polyaluminum hydroxide compound is preferably used. The main components of this compound are represented by the following general formulas 1, 2
Or 3 and, for example, [Al ₆ (OH) ₁₅ ] ³⁺ , [A
l ₈ (OH) ₂₀ ] ⁴⁺ , [Al ₁₃ (OH) ₃₄ ] ⁵⁺ , [Al
It is a water-soluble polyaluminum hydroxide which stably contains basic and polymeric polynuclear condensed ions such as ₂₁ (OH) ₆₀ ] ³⁺ .

[Al ₂ (OH) _n Cl _6-n ] _m ··· Formula 1 [Al (OH) ₃ ] _n AlCl ₃ · · Formula 2 Al _n (OH) _m Cl _(3n-m) 0 <m < 3n ... Equation 3

These are water treatment agents under the name of poly aluminum chloride (PAC) from Taki Chemical Co., Ltd., under the name of poly aluminum hydroxide (Paho) from Asada Chemical Co., Ltd. It is commercially available from Riken Green under the name Purachem WT and from other manufacturers for the same purpose, and various grades are easily available. In the present invention, these commercial products can be used as they are. These basic polyaluminum hydroxide compounds are also described in Japanese Patent Publication No. 3-24907 and No. 3-42591.

In the present invention, the content of the above-mentioned water-soluble polyvalent metal compound in the ink receiving layer is 0.1 g / m ² to.
10 g / m ^2, and preferably from ^{0.2g / m 2 ~5g / m 2} .

In the present invention, the ink receiving layer may contain various oil droplets in order to improve the brittleness of the film. Such oil droplets include hydrophobic high-boiling point organic solvents having a solubility in water of 0.01% by mass or less at room temperature (for example, liquid paraffin, dioctyl phthalate, tricresyl phosphate, silicone oil, etc.) and polymer particles ( For example, particles obtained by polymerizing one or more polymerizable monomers such as styrene, butyl acrylate, divinylbenzene, butyl methacrylate, hydroxyethyl methacrylate) can be contained. Such oil droplets can be preferably used in the range of 10 to 50% by mass with respect to the hydrophilic binder.

In the present invention, the ink receiving layer preferably contains a hardener together with an organic binder. Specific examples of the hardening agent include formaldehyde, an aldehyde compound such as glutaraldehyde, diacetyl,
Ketone compounds such as chlorpentanedione, bis (2-
Chloroethylurea) -2-hydroxy-4,6-dichloro-1,3,5triazine, U.S. Pat. No. 3,288,7
No. 75, a compound having a reactive halogen, such as divinyl sulfone, a compound having a reactive olefin, such as those described in US Pat. No. 3,635,718, and an N-- compound such as described in US Pat. No. 2,732,316. Methylol compounds, isocyanates such as those described in US Pat. No. 3,103,437, US Pat. Nos. 3,017,280 and 2,
983,611, aziridine compounds, US Pat. No. 3,100,704, carbodiimide compounds, US Pat. No. 3,091,537, epoxy compounds, and mucochloric acid, halogen carboxaldehydes. And dioxane derivatives such as dihydroxydioxane, inorganic hardeners such as chromium alum, zirconium sulfate, boric acid and borates.
They may be used alone or in combination of two or more. Among these, boric acid or borate is particularly preferable. The amount of the hardener added is preferably 0.1 to 40% by mass, and more preferably 0.5 to 30% by mass, with respect to the hydrophilic binder constituting the ink receiving layer.

The ink receiving layer further includes a coloring dye, a coloring pigment, a fixing agent for the ink dye, an ultraviolet absorber, an antioxidant,
Various known additives such as a pigment dispersant, a defoaming agent, a leveling agent, a preservative, a fluorescent whitening agent, a viscosity stabilizer, and a pH adjusting agent may be added. The pH of the coating liquid for the ink receiving layer of the present invention is preferably in the range of 3.3 to 6.0,
Especially, the range of 3.5 to 5.5 is preferable. By combining the pH of the coating liquid for the ink receiving layer and the pH of the coating liquid for the upper layer containing colloidal silica of 3.3 to 6, further ink absorbency, glossiness and uniform coating surface can be obtained.

The ink jet recording material of the present invention further has a layer containing colloidal silica and a cationic compound (hereinafter referred to as colloidal silica layer) on the above-mentioned ink receiving layer. This colloidal silica layer is preferably the outermost layer (outermost layer).

The colloidal silica used in the present invention is
It is obtained by metathesis of sodium silicate by an acid or the like and silica sol obtained through an ion exchange resin layer and heat-aged to obtain silicon dioxide, which is dispersed in water in a colloidal form, and has an average primary particle size of several nm to 100 nm. It is a wet process synthetic silica. As colloidal silica, Snowtex ST-20, ST-3 from Nissan Chemical Industries, Ltd.
0, ST-40, ST-C, ST-N, ST-20L,
ST-O, ST-OL, ST-S, ST-XS, ST-
XL, ST-YL, ST-ZL, ST-OZL, ST-
AK and the like are commercially available.

The colloidal silica used in the present invention is
The average primary particle size is 30 from the viewpoint of ink absorbency and gloss.
Those in the range of nm to 100 nm are preferable. Further, it is preferable to use two or more kinds of colloidal silica having different average primary particle diameters in combination. In this case, the average primary particle size is 30
It is more preferable to use colloidal silica having an average primary particle diameter of 60 nm or more and 100 nm or less in combination with colloidal silica having an average primary particle diameter of 30 nm or more and less than 60 nm, and an average primary particle diameter of 30 nm or more and less than 60 nm with respect to the total amount of colloidal silica. The ratio is preferably 60% by mass or more.

The particle shape of the above colloidal silica may be spherical, chain-like (beaded), or the like.
In particular, spherical colloidal silica is preferable in terms of scratch resistance and gloss. Further, the above colloidal silica has anionic, nonionic, and cationic properties, but the stability of the coating liquid for the colloidal silica layer, especially the stability of the coating liquid containing polyvinyl alcohol as an organic binder (depending on the aging of the coating liquid) Anionic property is preferable in terms of aggregation and separation of colloidal silica).

The solid coating amount of colloidal silica in the colloidal silica layer is preferably 0.1~8.0g / m ^2, the range of 0.3 to 5.0 g / m ² is more preferable. As a result, the glossiness and scratch resistance can be further improved without lowering the ink absorbability.

In the present invention, the colloidal silica layer contains a cationic compound, and a cationic polymer or a water-soluble polyvalent metal compound is preferably used as the cationic compound. The details of these cationic polymers and water-soluble polyvalent metal compounds are the same as those described in the ink receiving layer. In the present invention, the cationic compound used in the colloidal silica layer is preferably a cationic polymer.

The amount of the above-mentioned cationic compound added is preferably 0.1 to 10% by mass based on the colloidal silica.
The range of 0.5 to 8.0 mass% is more preferable.

The colloidal silica layer preferably further contains an organic binder. The organic binder is preferably used in an amount of 10% by mass or less based on colloidal silica, and the lower limit is about 0.5% by mass. More preferably,
The organic binder is used in the range of 1 to 7% by mass. By including the organic binder in this range, the scratch resistance is further improved without lowering the ink absorbency.

Examples of the organic binder include the above-mentioned organic binders used in the ink receiving layer. Among these, particularly preferred organic binders are completely or partially saponified polyvinyl alcohol or cation-modified polyvinyl alcohol. Especially preferred among the polyvinyl alcohols is a saponification degree of 80%.
The above is a partially or completely saponified product. Polyvinyl alcohol having an average degree of polymerization of 500 to 5000 is preferable.

As the cation-modified polyvinyl alcohol, for example, as described in JP-A No. 61-10483, primary to tertiary amino groups and quaternary ammonium groups are added to the main chain or side chain of polyvinyl alcohol. It is polyvinyl alcohol contained therein.

For the colloidal silica layer, a hardener can be used together with an organic binder. Examples of the hardener include the hardeners used in the ink receiving layer described above. Among these hardeners, boric acid or borate is preferably used. In the colloidal silica layer, in addition, a surfactant, a coloring dye, a coloring pigment, an ultraviolet absorber, an antioxidant, a pigment dispersant, a defoaming agent, a leveling agent, a preservative, an optical brightener, a viscosity stabilizer, A pH adjusting agent or the like can be contained.

The ink jet recording material of the present invention comprises a coating liquid for an ink receiving layer containing at least one layer of inorganic fine particles as a main component on a support, and a layer containing colloidal silica and a cationic compound (colloidal silica layer). It is manufactured by applying the coating solutions in this order, and it is important that the pH of the coating solution for the colloidal silica layer is in the range of 3.3 to 6.0. More preferably, the pH of the coating liquid for the colloidal silica layer is 3.5 to 5.5.

By coating a coating solution for a colloidal silica layer containing a cationic compound and having a pH in the range of 3.3 to 6.0 on the ink receiving layer, scratch resistance and gloss are improved. In particular, the ink absorbability is significantly improved, and in addition, aggregation at the interface between the ink receiving layer and the colloidal silica layer is eliminated, and uneven coating and uneven gloss are eliminated.

In the present invention, the coating method of the ink receiving layer and the colloidal silica layer is a sequential coating method of coating one layer at a time (for example, blade coater, air knife coater, roll coater, bar coater, gravure coater, reverse coater, etc.). Or the multilayer simultaneous multilayer coating method (for example, a slide bead coater or a slide curtain coater) can obtain the effects of the present invention, the multilayer simultaneous multilayer coating method is preferably used.

Conventionally, the ink receiving layer and the colloidal silica layer were generally applied sequentially (a method of applying the ink receiving layer and then drying the colloidal silica layer), but the colloidal silica layer is applied with colloidal silica. It was found that when the amount of solid content is 8 g / m ² or less, and further when it is 5 g / m ² or less, successive coating does not sufficiently exert the effect of gloss and scratch resistance of the colloidal silica layer. This is because when a relatively thin colloidal silica layer is applied on the ink receiving layer mainly containing the coated and dried inorganic fine particles, the coating liquid for the colloidal silica layer is partially contained in the voids in the ink receiving layer. It is believed that this is because it penetrates and a uniform colloidal silica layer cannot be obtained. Also,
The air present in the voids in the ink receiving layer diffuses into the coating liquid of the upper colloidal silica layer to form bubbles, which can cause crater-shaped coating defects (crater-shaped cissing), and the uniform colloidal silica layer It was an obstacle to the application.

Further, as the inorganic fine particles of the ink receiving layer, vapor phase method silica having an average primary particle diameter of 50 nm or less,
When alumina or alumina hydrate is used, particularly when vapor phase silica is used, the ink receiving layer containing these inorganic fine particles is once applied and dried, and then the colloidal silica layer is applied, and the ink receiving layer is used. In the process of re-wetting and drying, the ink receiving layer may cause minute cracks.

The above-mentioned problem in the case of sequentially coating the relatively thin colloidal silica layer after the coating and drying of the ink receiving layer is solved by the simultaneous multilayer coating of the ink receiving layer and the colloidal silica layer. In the present invention,
The thin layer coating of the colloidal silica layer is preferable from the viewpoint of ink absorbency. Since colloidal silica is inferior in ink absorbability to other inorganic fine particles, for example, vapor-phase method silica, which is preferably used in the ink receiving layer of the present invention, alumina or alumina hydrate, when a colloidal silica layer is provided as an upper layer. Is preferably a thin layer. On the other hand, colloidal silica has excellent gloss and scratch resistance, and if a uniform coating surface can be formed, sufficiently high gloss and scratch resistance effects can be obtained even with a thin layer. Therefore, in order to simultaneously satisfy high levels of ink absorbency, gloss, and scratch resistance, it can be said that it is extremely preferable to apply a thin colloidal silica layer simultaneously with an ink receiving layer mainly containing inorganic fine particles to form a multilayer coating.

In the multi-layer simultaneous multi-layer coating, a plurality of coating liquids for the ink receiving layer and the colloidal silica layer are coated on the support in a laminated state using a coater such as a slide bead coater or a slide curtain coater. When the coating liquid of the ink receiving layer and the colloidal silica layer are laminated,
A new problem has arisen that aggregation easily occurs at the interface between the two layers. The problem is that the colloidal silica layer contains a cationic compound, and the pH of the coating solution is 3.3 to 6.
It is solved by adjusting to the range of 0, preferably 3.5 to 5.5.

The preferred constitution of the colloidal silica layer is as described above, but the concentration of the colloidal silica in the coating liquid for the layer is suitably about 3 to 25% by mass, more preferably 5 to 15% by mass. . Wet coating amount of the colloidal silica layer coating liquid is preferably about ^{10~50g / m 2, 10~30g / m} 2 is more preferable.

The constitution of the ink receiving layer is also as described above, but the concentration of the inorganic fine particles in the coating liquid for the ink receiving layer is preferably about 5 to 20% by mass. Even when the ink receiving layer is composed of a plurality of layers, it is preferable that the concentration of the inorganic fine particles in each layer is within the above range. The appropriate amount of moisture applied to the ink receiving layer coating solution is about 100 to 300 g / m ^{2 in} total, whether it is a single layer or a plurality of layers. The pH of the coating liquid for the ink receiving layer is preferably 3.3 to 6, and more preferably 3.5 to 5.5. By adjusting the pH within this range, the ink absorbency is improved, and further aggregation at the interface with the upper colloidal silica layer is further suppressed.

The support used in the present invention includes polyester resins such as polyethylene terephthalate, diacetate resins, triacetate resins, acrylic resins, polycarbonate resins, polyvinyl chloride, polyimide resins,
Plastic resin film such as cellophane, celluloid,
Also, a water-resistant support such as a paper and a resin film bonded together, or a polyolefin resin-coated paper in which a hydrophobic resin such as a polyolefin resin is laminated on at least one surface of the paper is preferable. The thickness of these water resistant supports is 50 to 300.
μm, preferably 80 to 260 μm is used.

The polyolefin resin-coated paper support preferably used in the present invention (hereinafter referred to as polyolefin resin-coated paper) will be described in detail. The water content of the polyolefin resin-coated paper used in the present invention is not particularly limited, but is preferably in the range of 5.0 to 9.0%, more preferably 6.0 to 9.0% in terms of curling property. It is a range. The water content of the polyolefin resin-coated paper can be measured using an arbitrary water content measuring method. For example, an infrared moisture meter, an absolute dry weight method, a dielectric constant method, a Karl Fischer method or the like can be used.

The base paper constituting the polyolefin resin coated paper is not particularly limited, and commonly used paper can be used, but more preferably, for example, a smooth base paper used as a photographic support is preferred. . As the pulp constituting the base paper, one kind or a mixture of two or more kinds of natural pulp, recycled pulp, synthetic pulp and the like is used. This base paper has a sizing agent, a paper strengthening agent, which are generally used in papermaking,
Additives such as fillers, antistatic agents, optical brighteners and dyes are blended.

Further, a surface sizing agent, a surface paper strength agent, a fluorescent whitening agent, an antistatic agent, a dye, an anchoring agent or the like may be applied on the surface.

The thickness of the base paper is not particularly limited, but it is preferable that the paper has good surface smoothness, such as being compressed by applying pressure with a calendar or the like during or after the paper making, and its basis weight is 30 to 250 g / m ² is preferable.

As the polyolefin resin for coating the base paper, homopolymers of olefins such as low density polyethylene, high density polyethylene, polypropylene, polybutene and polypentene or copolymers of two or more olefins such as ethylene-propylene copolymers are used. As a coalesced product and a mixture thereof, those having various densities and melt viscosity indexes (melt indexes) can be used alone or by mixing them.

In the resin of the polyolefin resin coated paper, white pigments such as titanium oxide, zinc oxide, talc and calcium carbonate, fatty acid amides such as stearic acid amide and arachidic acid amide, zinc stearate, calcium stearate and stearin. Fatty acid metal salts such as aluminum acid salt and magnesium stearate, antioxidants such as Irganox 1010 and Irganox 1076,
Various additives such as cobalt blue, ultramarine blue, cesian blue, phthalocyanine blue and other blue pigments and dyes, cobalt violet, fast violet, magenta pigments and dyes such as manganese purple, optical brighteners and ultraviolet absorbers It is preferable to add them in combination.

The main production method of the polyolefin resin-coated paper is a so-called extrusion coating method in which a polyolefin resin is cast on a running base paper in a molten state by heating, and at least one surface thereof is coated with the resin. Further, it is preferable that the base paper is subjected to an activation treatment such as a corona discharge treatment or a flame treatment before the resin is coated on the base paper. From the viewpoint of ink absorbency, it is preferable not to cover the surface of the base paper on which the ink receiving layer is provided (front surface of the base paper) with the resin, and to prevent curling on the opposite surface (back side of the base paper). preferable. The back surface is usually a matte surface, and the back surface or both the front and back surfaces can be subjected to activation treatment such as corona discharge treatment and flame treatment as required. The thickness of the resin coating layer is not particularly limited, but is generally 5 to 50 μm on one side and resin is coated on one side or both sides. When only one surface is coated with a resin, the thickness of the polyolefin resin coating layer is preferably about 5 to 25 μm from the viewpoint of curl of the obtained ink jet recording material.

The surface of the polyolefin resin-coated paper of the present invention on which the ink receiving layer is applied (hereinafter referred to as the surface of the polyolefin resin-coated paper) may be the base paper surface, but from the viewpoint of gloss and smoothness, the polyolefin is used. It is manufactured by heating and melting a resin with an extruder, extruding it into a film form between a base paper and a cooling roll, press-bonding and cooling. At this time, the cooling roll is used to form the surface shape of the polyolefin resin coating layer, and the surface of the resin layer is shaped into a mirror surface, a finely rough surface, or a patterned silk-like or matte shape depending on the shape of the cooling roll surface. It can be processed.

The surface of the polyolefin resin-coated paper of the present invention on which the ink receiving layer is coated (hereinafter referred to as the back surface of the polyolefin resin-coated paper) may be the base paper surface when the surface is resin-coated. In order to improve the curl property and the printed image, a polyolefin resin is mainly heated and melted by an extruder, extruded in a film form between a base paper and a cooling roll, and pressure-bonded and cooled to produce the film. At this time, the cooling roll is JIS-B based on the transportability of the printer and the printed image.
It is preferable to perform a patterning process on the surface of the cooling roll so that Ra defined by −0601 is 0.8 to 5 μm, which is slightly roughened according to the shape of the surface of the cooling roll, or patterned, for example, silk or mat.

The method for forming the polyolefin resin coating layer on the back surface or the surface of the base paper is as follows: extruding the heat-melting resin and applying the resin, and then irradiating an electron beam after applying the electron beam curing resin, or a polyolefin resin emulsion. There is a method of applying the coating liquid of (1) and drying it to perform surface smoothing treatment. In either case, a polyolefin resin-coated paper applicable to the present invention can be obtained by imprinting with a heat roll having irregularities.

An undercoat layer may be provided on the surface of the polyolefin resin-coated paper used in the present invention. The undercoat layer is applied and dried on the surface of the water-resistant support in advance before the ink receiving layer is applied. This undercoat layer is
It mainly contains a water-soluble polymer or polymer latex capable of forming a film. Water-soluble polymers such as gelatin, polyvinyl alcohol, polyvinylpyrrolidone and water-soluble cellulose are preferable, and gelatin is particularly preferable. The adhesion amount of these water-soluble polymers is 10 to 50.
Preferably ^{0mg / m 2, 20~300mg / m} 2 is more preferable. Furthermore, it is preferable that the undercoat layer further contains a surfactant or a hardener. Further, it is preferable to perform corona discharge before applying the undercoat layer to the resin-coated paper.

[0066]

The present invention will be described in detail below with reference to examples, but the contents of the present invention are not limited to the examples.

Example 1 <Preparation of polyolefin resin coated paper> Hardwood bleached kraft pulp (LBKP) and hardwood bleached sulfite pulp (L
A 1: 1 mixture of BSP) was beaten to 300 ml with Canadian Standard Freeness to prepare a pulp slurry. Alkyl ketene dimer as a sizing agent to 0.5% by weight of pulp, polyacrylamide as a strength agent to 1.0% by weight of pulp, cationized starch to 2.0% by weight of pulp, and polyamide epichlorohydrin resin. 0.5% by mass of pulp was added and diluted with water to obtain a 1% slurry. This slurry was made into a paper by a Fourdrinier paper machine so as to have a basis weight of 170 g / m ² , dried and conditioned to obtain a base paper for a polyolefin resin-coated paper. A polyethylene resin composition in which 10% by mass of anatase-type titanium was uniformly dispersed in 100% by mass of a low-density polyethylene resin having a density of 0.918 g / cm ³ was melted at 320 ° C. in a paper-making base paper, and 200 m / Min to give a thickness of 35 μm, and extrusion coating was carried out using a cooling roller having a micro-roughened surface. Density 0.962g / cm on the other side
70 parts by mass of high density polyethylene resin ³ and density 0.91
Similarly, 30 parts by mass of the low-density polyethylene resin of Example 8 was melted at 320 ° C., extrusion-coated to a thickness of 30 μm, and extrusion-coated using a roughened cooling roll.

A high frequency corona discharge treatment was applied to the surface of the above polyolefin resin coated paper, and an undercoat layer having the following composition was coated and dried so that gelatin was 50 mg / m ² to prepare a support. In addition, a part represents the mass part of solid content.

[0069] <Undercoat layer> 100 parts of lime-processed gelatin Sulfosuccinic acid-2-ethylhexyl ester salt 2 parts Chrome Alum 10 copies

An ink-receiving layer coating solution having the following composition and a colloidal silica layer coating solution having the following compositions were simultaneously coated on the surface of the obtained support, on which the undercoat layer was provided, with a slide bead coater.
The concentration of vapor phase silica in the coating liquid for the ink receiving layer was adjusted to 9% by mass. The wet coating amount of the ink receiving layer coating liquid is 200 g / m ² (the solid coating amount of vapor phase silica is 18 g / m ² ). The colloidal silica layer coating solution was prepared so that the concentration of colloidal silica was 8% by mass. The amount of moisture of the colloidal silica layer coating liquid is 12.
5 g / m ² (the solid coating amount of colloidal silica is 1
g / m ² ).

<Ink Receptor Layer Coating Liquid> 100 parts of vapor phase silica (average primary particle size: 7 nm, specific surface area by BET method: 300 m ² / g) Dimethyldiallylammonium chloride homopolymer 4 parts (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) , Charol DC902P, molecular weight 9000) Boric acid 3 parts Polyvinyl alcohol 22 parts (saponification degree 88%, average degree of polymerization 3500) Basic polyaluminum hydroxide 3 parts (trade name: Purachem WT, Riken Green Co., Ltd.) Surface active Agent 0.3 parts (betaine type; manufactured by Nippon Surfactant Co., Ltd., Suwanol AM) The pH of the coating solution was adjusted to 4.0.

[0072] <Colloidal silica layer coating liquid A> 100 parts of colloidal silica   (Anionic spherical colloidal silica; Snowtex ST-OL40 manufactured by Nissan Chemical Industries, Ltd.,     (Average primary particle size 40 to 50 nm) Cationic polymer; Polyfix 601 1 part   (Showa High Polymer Co., specially modified polyamine) Polyvinyl alcohol 4 parts   (Saponification degree 88%, average degree of polymerization 3500) Surfactant 0.3 parts (Betaine type; manufactured by Nippon Surfactant Co., Suwanol AM)

Coating liquid A for the above colloidal silica layer was prepared as follows. First, water is added so that the concentration of colloidal silica is 10% by mass to prepare an aqueous colloidal silica solution, and the aqueous solution of colloidal silica is stirred at high speed with a high-speed rotating disper while Polyfix 601.
(10% by mass solution) was added, and the mixture was stirred at high speed for 10 minutes, and then polyvinyl alcohol and a surfactant were sequentially added to prepare a coating liquid A. The pH of this coating liquid A was 3.0.

<Colloidal Silica Layer Coating Solution B> The colloidal silica layer coating solution A was prepared in the same manner as above. However,
While stirring the aqueous colloidal silica solution at high speed with a high-speed rotating disperser, 0.545% by mass of sodium hydroxide was gradually added in an amount of 0.045 parts in terms of solid content to raise the pH, and then the cationic polymer (Polyfix 601) was added. The mixture was further added, and the mixture was stirred at high speed for 10 minutes. Next, polyvinyl alcohol and a surfactant were sequentially added to prepare a coating solution. The pH of this coating solution was 3.5.

<Colloidal Silica Layer Coating Solution C> The colloidal silica layer coating solution B was prepared in the same manner as above. However, the amount of sodium hydroxide was adjusted to adjust the pH of the coating liquid to 4.0.

<Colloidal Silica Layer Coating Solution D> The colloidal silica layer coating solution B was prepared in the same manner as above. However, the amount of sodium hydroxide was adjusted to adjust the pH of the coating liquid to 5.0.

<Colloidal Silica Layer Coating Solution E> The colloidal silica layer coating solution B was prepared in the same manner as above. However, the amount of sodium hydroxide was adjusted to adjust the pH of the coating solution to 7.0.

<Colloidal Silica Layer Coating Solution F> The colloidal silica layer coating solution C was prepared in the same manner as above. However, the cationic polymer (Polyfix 601) was not added. The pH of the coating solution was adjusted to 4.0.

Ink jet recording materials A1 to F1 were prepared by simultaneously coating the above ink receiving layer and colloidal silica layers A to F in a multilayer structure. Ink absorbency, glossiness, and scratch resistance of each of the six types of recording materials were evaluated by the following methods. Furthermore, the degree of occurrence of unevenness on the coated surface was also evaluated. The results are shown in Table 1.

<Ink Absorption> Solid black printing was carried out with an ink jet printer PM-800C manufactured by Seiko Epson, and the state of ink absorption and the occurrence of mottling (image density unevenness) were visually observed and evaluated according to the following criteria. did. A: Ink is absorbed promptly and no mottling occurs. ○: Ink absorption is slightly slow, but no mottling occurs. Δ: Ink slightly overflows on the printed surface, and slight occurrence of mottling is recognized. X: Ink overflows on the printed surface, and strong mottling is clearly observed.

<Glossiness> The glossiness of the recording material before printing was observed by oblique light and evaluated according to the following criteria. ◯: Has a high glossiness comparable to that of a color photograph. Δ: There is a glossy feeling similar to that of art and coated paper. X: There is no glossiness comparable to art and coated paper.

<Scratch resistance> Two recording materials which are not printed are superposed on the surface, 100 g of weight is placed on the recording material, and the recording material below is taken out, and scratches on the ink receiving layer surface are visually observed. I observed. ◯: No scratch is recognized. Δ: Some scratches are recognized. X: A scratch is clearly recognized.

<Unevenness of Coating Surface> The occurrence of unevenness in the coating surface was visually observed and evaluated according to the following criteria. ◯: No unevenness is observed on the coated surface. Δ: Slight unevenness is recognized on the coated surface. X: Unevenness is clearly recognized on the coated surface.

[0084]

[Table 1] ───────────────────────────────────   Recording material Colloidal silica layer Ink absorption, gloss, scratch resistance, coating unevenness Remarks ───────────────────────────────────     A1 A △ △ △ △ Comparative Example     B1 B ◎ ○ ○ ○ The present invention     C1 C ◎ ○ ○ ○ The present invention     D1 D ◎ ○ ○ ○ The present invention     E1 E Δ Δ Δ Δ Δ Comparative example     F1 F × Δ × × × Comparative example ───────────────────────────────────

Example 2 On the same support as in Example 1, three layers of the following ink receiving layer coating liquid A and ink receiving layer coating liquid B and the colloidal silica layer coating liquid of Example 1 were simultaneously applied using a slide bead coater. Multiple layers were applied. The amount of moisture applied is 1 for the ink receiving layer coating liquid A.
70 g / m ² , the ink-receiving layer coating liquid B is 40 g / m ^2, and the colloidal silica layer coating liquid is 12.5 g / m ² .

<Ink receiving layer coating liquid> 100 parts of vapor phase silica (average primary particle size: 12 nm, specific surface area by BET method: 200 m ² / g) Dimethyl diallyl ammonium chloride homopolymer 4 parts (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) , Charol DC902P, molecular weight 9000) Boric acid 3 parts Polyvinyl alcohol 20 parts (saponification degree 88%, average degree of polymerization 3500) Basic polyaluminum hydroxide 3 parts (trade name: Purachem WT, manufactured by Riken Green Co., Ltd.) Surfactant Agent 0.3 parts (betaine type; manufactured by Nippon Surfactant Co., Ltd., Suwanol AM) The pH of the coating solution was adjusted to 4.0. The concentration of vapor phase silica in the coating liquid is 9% by mass.

<Ink Receptor Layer Coating Liquid B> Alumina hydrate 100 parts (pseudo-boehmite, average primary particle size 13 nm, flat plate with aspect ratio 3) Nitric acid 1 part Boric acid 0.5 part Polyvinyl alcohol 10 parts (Saponification degree 88%, average degree of polymerization 3500) Surfactant 0.3 part (betaine type; manufactured by Nippon Surfactant Co., Ltd., Swanol AM) The pH of the coating solution was adjusted to 4.2. The concentration of the alumina hydrate in the coating liquid is 15% by mass.

The above ink receiving layers A and B and the colloidal silica layers A to F were simultaneously coated in layers to prepare ink jet recording materials A2 to F2. The six types of recording materials were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0089]

[Table 2] ───────────────────────────────────   Recording material Colloidal silica layer Ink absorption, gloss, scratch resistance, coating unevenness Remarks ───────────────────────────────────     A2 A △ △ △ △ Comparative Example     B2 B ◎ ○ ○ ○ The present invention     C2 C ◎ ○ ○ ○ The present invention     D2 D ◎ ○ ○ ○ The present invention     E2 E △ △ △ △ Comparative Example     F2 F × Δ × × Comparative example ───────────────────────────────────

Example 3 Recording materials C3 and C4 were prepared according to the recording material C1 of Example 1.
Was produced. However, the colloidal silica layer coating liquid C was changed as follows.

<Preparation of Recording Material C3> The colloidal silica of the coating liquid C of the colloidal silica layer of Example 1 was prepared by using Snowtex ST-O (manufactured by Nissan Chemical Industries, Ltd.) having an average primary particle diameter of 10 to 20 nm. A colloidal silica layer coating solution C3 was prepared in the same manner except that the coating liquid C3 was replaced with a spherical shape.

<Preparation of Recording Material C4> The colloidal silica of the coating liquid C of the colloidal silica layer of Example 1 was prepared by using Snowtex ST-OL4 having an average primary particle diameter of 40 to 50 nm.
0 (manufactured by Nissan Chemical Industries, Ltd.) and an average primary particle size of 70
nm Snowtex ST-OZL (manufactured by Nissan Chemical Industries, Ltd., anionic sphere) (combination ratio; ST-
OL40: ST-OZL = 7: 3), except that the colloidal silica layer coating solution C4 was prepared in the same manner.

The two types of recording materials C3 and C4 and the recording material C1 of Example 1 were evaluated in the same manner as in Example 1. However, regarding the ink absorbency, the printing mode was changed and the amount of ink was increased for printing. The evaluation results are shown in Table 3.

[0094]

[Table 3] ───────────────────────────────────   Recording material Colloidal silica layer Ink absorption, gloss, scratch resistance, coating unevenness Remarks ───────────────────────────────────     C1 C ○ ○ ○ ○ The present invention     C3 C3 △ ○ ○ ○ The present invention     C4 C4 ◎ ○ ○ ○ The present invention ───────────────────────────────────

Example 4 A recording material was prepared according to the recording material C1 of Example 1.
However, the solid colloidal silica coating amount was changed as follows by increasing the colloidal silica concentration of the colloidal silica layer coating liquid and increasing the moisture coating amount. Recording material C5: Solid content of colloidal silica 3 g /
m ² Moisture application amount is 30 g / m ² (colloidal silica concentration is 10% by mass) Recording material C6: Colloidal silica solid content application amount is 6 g /
m ² Moisture application amount is 30 g / m ² (colloidal silica concentration is 20% by mass) Recording material C7: Colloidal silica solid content application amount is 10 g
/ M ² Moisture application amount is 40 g / m ² (colloidal silica concentration is 25% by mass)

The three kinds of recording materials C5 to C7 and the recording material C1 of Example 1 were evaluated in the same manner as in Example 1. The evaluation results are shown in Table 4.

[0097]

[Table 4] ─────────────────────────────────── Recording material Colloidal silica ink absorption, gloss, scratch resistance Characteristics Coating unevenness Remark Solid coating amount ─────────────────────────────────── C1 1 g / m ² ◎ ○ ○ ○ Invention C5 3 g / m ² ◎ ○ ○ ○ Invention C6 6 g / m ² ○ ○ ○ ○ Invention C7 10 g / m ² △ ○ ○ ○ Invention ────────── ──────────────────────────

Example 5 In accordance with Examples 1 and 4, recording materials having different coating amounts of solid content of colloidal silica were prepared. However, the coating liquid for the ink receiving layer was first applied and dried using a bar coater, and then the colloidal silica layer coating liquids F and C of Example 1 and the colloidal silica layers used for the recording materials C5, C6 and C7 of Example 4. The coating liquids were applied and dried using an air knife coater to prepare recording materials G1 to G5. The recording material thus prepared was evaluated for ink absorbency, gloss and scratch resistance in the same manner as in Example 1. Further, the coated surface was visually observed and evaluated according to the following criteria. The evaluation results are shown in Table 5.

<Coating surface> ◯: There is no uneven gloss and crater-like cissing. Δ: Uneven gloss and crater-like cissing are slightly observed. X: Uneven gloss and crater-like cissing are clearly observed.

[0100]

[Table 5] ─────────────────────────────────── Recording material Ink absorption and gloss of colloidal silica layer Scratch resistance Uneven coating Remarks Coating liquid Solid coating amount ─────────────────────────────────── G1 F 1g / m ² × △ × × Comparative example ^{G2 C 1g / m 2 ◎ △} △ × invention ^{G3 C5 3g / m 2 ◎ △} △ × invention ^{G4 C6 6g / m 2 ○ △} ○ △ present invention G5 C7 10g / m ² △ ○ ○ △ The present invention ────────────────────────────────────

[0101]

As is clear from the above examples, when the colloidal silica layer is provided as the upper layer (preferably the uppermost layer) of the ink receiving layer mainly containing inorganic fine particles, the cationic compound of the colloidal silica layer is added. And the pH of the coating solution is in the range of 3.3 to 6.0, more preferably p
Ink absorptivity, glossiness of the inkjet recording material produced by adjusting to H3.5 to 5.5,
Scratch resistance is improved and coating unevenness is further suppressed. Further, by using colloidal silica having an average primary particle diameter of 30 nm or more for the colloidal silica layer, ink absorbency is improved, and further 30 nm or more and less than 60 nm and 60 nm or more
By using colloidal silica of less than 100 nm in combination, the ink absorbability is further improved. Further, the solid content of colloidal silica in the colloidal silica layer is 0.3 to
8.0 g / m ² range, even in the range of 0.3 to 5.0 g / m ^2, is achieved one step improvement in ink absorption. Furthermore, by simultaneously coating the ink receiving layer mainly containing inorganic fine particles and the colloidal silica layer, preferable results can be obtained in terms of uniformity of coated surface, glossiness, and scratch resistance as compared with sequential coating. . This effect is particularly due to the solid content coating amount of the colloidal silica layer being 8.0 g / m ² or less, and further 5.
Remarkably appears at 0 g / m ² or less.

Claims (9)

[Claims] 1. An inkjet formed by coating a support with a coating liquid for an ink receiving layer containing at least one layer of inorganic fine particles as a main component and a coating liquid for a layer containing colloidal silica and a cationic compound in this order. In recording material,
An ink jet recording material, wherein the coating liquid for the layer containing the colloidal silica has a pH of 3.3 to 6.0. 2. The pH of the coating liquid of the ink receiving layer containing the inorganic fine particles as a main component is 3.3 to 6.0.
The method for producing an ink jet recording material according to 1. 3. The ink jet recording material according to claim 1, wherein the coating liquid for the ink receiving layer mainly containing the inorganic fine particles and the coating liquid for the layer containing the colloidal silica are simultaneously and multilayer coated. 4. The ink jet recording material according to claim 1, 2 or 3, wherein the cationic compound is a cationic polymer. 5. The ink jet recording material according to claim 1, wherein the colloidal silica has an average primary particle size of 30 nm or more. 6. A layer containing the colloidal silica,
The inkjet recording material according to claim 1, wherein the organic binder is contained in an amount of 1 to 7 mass% with respect to the colloidal silica. 7. The inkjet recording material according to claim 1, wherein the coating amount of the colloidal silica is 0.3 to 8.0 g / m ² in terms of solid content. 8. The inkjet recording material according to claim 1, wherein the inorganic fine particles are vapor grown silica, alumina, or alumina hydrate. 9. The coating amount of the inorganic fine particles is 15 in terms of solid content.
The inkjet recording material according to any one of claims 1 to 8, which has a g / m ² or more.