JP2007175897A - Inkjet recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording material being excellent in flaw resistance and ink absorbency and suitable for the use as a postcard. <P>SOLUTION: The inkjet recording material includes: on one side of a water-resistant substrate, an ink accepting layer mainly containing inorganic particulates having an average secondary particle diameter of 500 nm or less; and an ink accepting layer containing colloidal silica as the uppermost layer, of at least two ink accepting layers. At least either of the ink accepting layers contains a hydrazine derivative. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  An object of the present invention is to provide a photo-like ink jet recording material, and more specifically, to provide an ink jet recording material excellent in scratch resistance and ink absorbability. Another object of the present invention is to provide an ink jet recording material suitable for postcard applications.

  Conventionally, as a means for imparting scratch resistance to a photo-like ink jet recording material, it is known to provide a colloidal silica layer on a porous ink receiving layer. For example, providing a colloidal silica layer on a gas phase method silica layer is described in Japanese Patent Application Laid-Open No. 2000-37944 (Patent Document 1), and a layer containing a gas phase method silica or alumina hydrate is used. JP-A 2003-94800 (Patent Document 2) describes that a colloidal silica layer is provided thereon.

  However, in the conventional recording materials as described above, the ink absorptivity decreases as the scratch resistance is improved, and the scratch resistance and ink absorptivity intended by the present invention cannot be satisfied at the same time.

  On the other hand, there is known a recording material in which an ink receiving layer is provided on both sides of a water-resistant support and printing on both sides is possible. These recording materials are known for postcard applications. When used as a postcard, it is common to print a postal code frame or the like on the address side with a printing machine. However, with conventional recording materials that can be printed on both sides, the feeder part of the printing machine A large number of rubber rollers and brushes damage the ink receiving layer on the address surface, and as a result, there is a problem that the blanket becomes dirty and the printing efficiency is deteriorated. For this reason, the ink receiving layer on the address side is required to have higher scratch resistance. However, the conventional technology described above cannot achieve both sufficient scratch resistance and ink absorbability.

  It is also known that a porous ink receiving layer contains a hydrazine derivative. For example, a hydrazine derivative may be contained in an ink-receiving layer containing vapor phase method silica. JP 2002-321447 A (Patent Literature 3), JP 2002-337448 A (Patent Literature 4), precipitation method silica. Japanese Patent Application Laid-Open No. 2004-243740 (Patent Document 5) describes that a hydrazine derivative is contained in an ink-receiving layer containing a hydrazine.

However, the above-described technique is intended to improve the storability of a printed image, and does not disclose a technique that satisfies the ink absorption and scratch resistance improvements, which are the objects of the present invention.
JP 2000-37944 A JP 2003-94800 A JP 2002-321447 A JP 2002-337448 A JP 2004-243740 A

  Accordingly, an object of the present invention is to provide an ink jet recording material that can satisfy ink absorbency and scratch resistance at the same time. Another object of the present invention is to provide an ink jet recording material suitable for postcard use, in which blanket smear does not occur when printing is performed with a printing press.

The above object of the present invention has been achieved by the following invention.
1) At least 2 having an ink receiving layer mainly containing inorganic fine particles having an average secondary particle diameter of 500 nm or less and an ink receiving layer containing colloidal silica as the uppermost layer on one surface (A surface) of the water-resistant support. An ink jet recording material having an ink receiving layer, wherein at least one of the ink receiving layers contains a hydrazine derivative.
2) The ink jet recording material according to 1), wherein the uppermost ink receiving layer contains substantially no hydrazine derivative.
3) The ink jet recording material according to 1) or 2), wherein the water-resistant support is a resin-coated paper.
4) The ink jet recording according to any one of 1) to 3), which has an ink receiving layer mainly containing inorganic fine particles having an average secondary particle diameter of 500 nm or less on the opposite surface (B surface) of the water-resistant support. material.
5) An inkjet recording material in which the inkjet recording material described in 4) is used for postcards.

  By practicing the present invention, it is possible to provide an ink jet recording material that can simultaneously satisfy scratch resistance and ink absorbability. In addition, it is possible to provide an ink jet recording material suitable for a postcard application in which blanket stains do not occur when printing with a printing press.

Hereinafter, the ink jet recording material of the present invention will be described in detail.
The ink jet recording material of the present invention has a photo-like quality, and a water-resistant support is used. For example, a polyester resin, a diacetate resin, a triacetate resin, an acrylic resin, a polyvinyl chloride resin, a cellophane, etc., which is coated with a thermoplastic resin such as a polyolefin resin on at least one side of a base paper, A resin-coated paper support or the like is used. Among these, a particularly preferred water-resistant support is a resin-coated paper support.

  The resin-coated paper used in the present invention will be described in detail. The base paper constituting the resin-coated paper support is not particularly limited, and commonly used paper can be used. However, for example, a smooth base paper used for a photographic support is preferable. As the pulp constituting the base paper, natural pulp, recycled pulp, synthetic pulp or the like is used alone or in combination of two or more. This base paper is blended with additives such as sizing agent, paper strength enhancer, filler, antistatic agent, fluorescent whitening agent, and dye generally used in papermaking. Further, a surface sizing agent, surface paper strengthening agent, fluorescent brightening agent, antistatic agent, dye, anchor agent and the like may be applied on the surface.

The base paper used as the base paper is preferably a product having good surface smoothness, such as being compressed by applying pressure during or after paper making, and the basis weight is preferably 30 to 180 g / m ² .

  The resin used for the resin layer covering the base paper includes olefin homopolymers such as low-density polyethylene, high-density polyethylene, polypropylene, polybutene, and polypentene, and copolymers comprising two or more olefins such as ethylene-propylene copolymer. Examples thereof include polymers and mixtures thereof, and those having various densities and melt viscosity indexes (melt index) can be used alone or in combination.

  In the resin layer, fatty acid amides such as stearic acid amide and arachidic acid amide, fatty acid metal salts such as zinc stearate, calcium stearate, aluminum stearate, magnesium stearate, irganox 1010, irganox 1076 and the like are oxidized. Various additives such as inhibitors, blue pigments and dyes such as cobalt blue, ultramarine blue, cecilian blue, and phthalocyanine blue, magenta pigments and dyes such as cobalt violet, fast violet, and manganese purple, fluorescent whitening agents, and UV absorbers Agents can be added in appropriate combinations.

  A general method for producing a resin-coated paper is produced by a so-called extrusion coating method in which a polyolefin resin heated and melted is cast on a traveling base paper, and both surfaces of the base paper are coated with a resin. Prior to coating the base paper with the resin, it is preferable to subject the base paper to an activation treatment such as corona discharge treatment or flame treatment. The thickness of the resin layer is suitably in the range of 5 to 50 μm.

  As described above, the resin-coated paper is manufactured by extruding a heat-melted resin into a film between a base paper and a cooling roll, pressing and cooling. At this time, the cooling roll is used for forming the surface shape of the resin layer, and the center line average roughness of the surface of the resin layer is obtained by adjusting the surface shape of the cooling roll to be used.

  Various back coat layers can be coated on the above-mentioned resin-coated paper for antistatic property, transportability, curl prevention and the like. In the backcoat layer, an inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, latex, a curing agent, a pigment, a surfactant, and the like can be appropriately combined. In addition, it is preferable to previously provide an undercoat layer made of a hydrophilic binder such as gelatin on the surface on which the ink receiving layer is applied.

  The ink jet recording material of the present invention has an ink receiving layer mainly containing inorganic fine particles having an average secondary particle diameter of 500 nm or less on the above-mentioned support, and further has an uppermost layer containing colloidal silica. “Containing mainly inorganic fine particles” means that the inorganic fine particles are contained in an amount of 50% by mass or more, preferably 60% by mass or more, and more preferably 65% by mass or more based on the total solid content of the ink receiving layer. That is.

As the inorganic fine particles, gas phase method silica, finely pulverized wet method silica, and alumina hydrate are preferably used. In particular, gas phase method silica is preferable from the viewpoint of ink absorbability. By using inorganic fine particles having an average secondary particle diameter of 500 nm or less, a high-color printability and high-definition printed image can be obtained. In order to obtain high ink absorbability, the coating amount of the inorganic fine particles in the ink receiving layer needs to be 10 g / m ² or more, and the upper limit is about 50 g / m ² .

  Vapor phase silica is also called a dry method, and is generally produced by flame hydrolysis. Specifically, a method of making silicon tetrachloride by burning with hydrogen and oxygen is generally known, but silanes such as methyltrichlorosilane and trichlorosilane can be used alone or with silicon tetrachloride instead of silicon tetrachloride. It can be used in a mixed state. Vapor phase method silica is commercially available as Aerosil from Nippon Aerosil Co., Ltd. and QS type from Tokuyama Co., Ltd., and can be obtained.

  Wet method silica is further classified into precipitation method silica, gel method silica, and sol method silica according to the production method. Precipitated silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions. The silica particles that have grown in the manufacturing process are aggregated and settled, and then processed through filtration, washing with water, drying, pulverization and classification. The secondary particles of silica produced by this method become loose agglomerated particles, and particles that are relatively easy to grind are obtained. Precipitated silica is commercially available, for example, as a nip seal from Tosoh Silica Co., Ltd., as a Toku Seal from Tokuyama Co., Ltd., and as a fine seal.

  Gel silica is produced by reacting sodium silicate and sulfuric acid under acidic conditions. In this case, the small silica particles dissolve during ripening and reprecipitate so as to bond the primary particles between the primary particles of the large particles, so that the distinct primary particles disappear and are relatively hard agglomerates with an internal void structure Form particles. For example, it is commercially available as Mizusukacil from Mizusawa Chemical Industry Co., Ltd. and as a silo jet from Grace Japan Co., Ltd.

  The sol method silica is also called colloidal silica. In the present invention, it is used as the uppermost layer of the ink receiving layer and will be described in detail later.

The vapor phase method silica preferably has an average primary particle size of 50 nm or less. In order to obtain higher gloss, gas phase method silica having a specific surface area of 5 to ²⁰ nm and a BET method of 90 to 400 m ² / g is preferable. The BET method referred to in the present invention is one of powder surface area measurement methods by vapor phase adsorption, and is a method for determining the total surface area, that is, the specific surface area of a 1 g sample from the adsorption isotherm. Usually, nitrogen gas is often used as the adsorbed gas, and the most frequently used method is to measure the amount of adsorption from the change in pressure or volume of the gas to be adsorbed. The most prominent expression for expressing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller equation, called the BET equation, which is widely used for determining the surface area. The adsorption amount is obtained based on the BET equation, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

  Vapor phase silica is present in a state where primary particles of several nm to several tens of nm are secondarily aggregated by being linked in a network structure or a chain. The agglomerated particles are preferably dispersed until the average secondary particle diameter is 500 nm or less, more preferably 300 nm or less. The lower limit particle size is about 30 nm. Here, the average particle diameter of the agglomerated particles can be determined by photography using a transmission electron microscope. For simplicity, the number of particles can be determined by using a laser scattering type particle size distribution meter (for example, LA910, manufactured by Horiba, Ltd.). It can be measured as the median diameter.

  In the present invention, the wet method silica preferably used is precipitation method silica and gel method silica, and more preferably precipitation method silica. The average secondary particle diameter of these wet process silicas is usually 1 μm or more. In the present invention, these wet process silicas are pulverized until the average secondary particle diameter is 500 nm or less. Preferably, it grind | pulverizes until an average particle diameter becomes 300 nm or less. The lower limit particle size is about 30 nm. The particle diameter of the pulverized wet process silica can be determined by a transmission electron microscope or a laser scattering type particle size distribution meter as described above.

  The pulverization step of the wet process silica includes a primary dispersion step in which silica fine particles are added to a dispersion medium and mixed (preliminary dispersion), and a secondary dispersion step in which the silica in the coarse dispersion obtained in the primary dispersion step is pulverized. . The preliminary dispersion in the primary dispersion step can be performed by ordinary propeller stirring, a toothed blade type dispersing machine, turbine type stirring, homomixer type stirring, ultrasonic stirring, or the like. As a wet method silica pulverization method, a wet dispersion method in which silica dispersed in a dispersion medium is mechanically pulverized can be preferably used. As the wet disperser, a media mill such as a ball mill, a bead mill, and a sand grinder, a pressure disperser such as a high pressure homogenizer, and an ultra high pressure homogenizer, an ultrasonic disperser, and a thin film winding disperser can be used. In the present invention, a media mill such as a bead mill is particularly preferably used.

  The wet process silica used in the present invention preferably has an average secondary particle diameter of 5 μm or more before pulverization. By pulverizing silica having a relatively large particle size, dispersion at a higher concentration is possible. The upper limit of the average particle diameter of the wet process silica used in the present invention is not particularly limited, but the average particle diameter of the commonly used wet process silica is 200 μm or less.

  In the present invention, a cationic compound is used in the dispersion step of the vapor phase method silica and the pulverization step of the wet method silica. As the cationic compound, a cationic polymer, a water-soluble polyvalent metal compound, or a silane coupling agent is used. Among these cationic compounds, a cationic polymer and a water-soluble polyvalent metal compound are particularly preferable, and a cationic polymer is particularly preferable.

  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 adduct of a primary to tertiary amine. For example, polyethylenimine, polydialkyldiallylamine, polyallylamine, allylamine epichlorohydrin polycondensate, JP 59-20696, JP 59-33176, JP 59-33177, JP 59-155088 JP-A-60-11389, JP-A-60-49990, JP-A-60-83882, JP-A-60-109894, JP-A-62-198493, JP-A-63-49478, Japanese Unexamined Patent Publication Nos. 63-115780, 63-280681, 1-40371, 6-234268, 7-125411, 10-193976, International Publication No. 99/64248 The cationic polymer described in the pamphlet etc. is mentioned. The weight average molecular weight of the cationic polymer used in the present invention is preferably 100,000 or less, more preferably 50,000 or less, and particularly preferably about 2,000 to 30,000.

  In this invention, the usage-amount of a cationic polymer has the preferable range of 1-10 mass% with respect to a synthetic silica.

  Examples of the water-soluble polyvalent metal compound used in the present invention include calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, titanium, chromium, magnesium, tungsten, and molybdenum, and these metals. It can be used as a water-soluble salt. 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, chloride chloride Dicopper, ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel sulfate Ammonium hexahydrate, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, ferrous bromide, ferric chloride Ferrous, ferric chloride, ferrous sulfate, ferric sulfate, zinc bromide, zinc chloride, zinc nitrate six Japanese products, 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, oxychloride Zirconium, hydroxy zirconium 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, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, and the like. Among these, aluminum or a water-soluble salt of a periodic table group IVa element (zirconium, titanium) is preferable. In the present invention, water-soluble means that 1% by mass or more dissolves in water at room temperature and normal pressure.

  The addition amount of the water-soluble polyvalent metal salt compound is preferably in the range of 0.1 to 10% by mass with respect to the synthetic silica.

As the inorganic fine particles used in the present invention, alumina hydrate can be used in addition to the vapor phase silica and the wet method silica. Alumina hydrate is represented by a constitutive formula of Al ₂ O ₃ .nH ₂ O (n = 1 to 3). The case where n is 1 represents an alumina hydrate having a boehmite structure, and the case where n is greater than 1 and less than 3 represents an alumina hydrate having a pseudo boehmite structure. It can be obtained by a known production method such as hydrolysis of an aluminum alkoxide such as aluminum isopropoxide, neutralization of an aluminum salt with an alkali, or hydrolysis of an aluminate.

  The average primary particle diameter of the above-mentioned alumina hydrate is preferably 5 to 50 nm, and in particular, 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 30 nm. preferable.

  In the ink receiving layer of the present invention, a hydrophilic binder is used in order to maintain the properties as a film, and in particular, a water-soluble binder that has high transparency and higher ink permeability is used. In using the hydrophilic binder, it is important that the hydrophilic binder does not swell during the initial permeation of the ink and block the gap. From this viewpoint, a hydrophilic binder having a low swelling property at a relatively near room temperature is preferable. Used. Polyvinyl alcohol, polyethylene glycol, starch, dextrin, carboxymethyl cellulose and the like and derivatives thereof are used, and preferred hydrophilic binders are fully or partially saponified polyvinyl alcohol or gelatin. Particularly preferred is a partially saponified polyvinyl alcohol having a saponification degree of 80% or more, and an average polymerization degree of 200-5000 is preferred.

  The ratio of the hydrophilic binder in the ink receiving layer is appropriately selected depending on the type of inorganic fine particles used. When vapor phase method silica is used for the ink receiving layer, the ratio of the hydrophilic binder is preferably 15 to 30% by mass, more preferably 16 to 27% by mass, particularly 17 to 25%, relative to the vapor phase method silica. A range of mass% is preferred. When wet process silica is used for the ink receiving layer, the ratio of the hydrophilic binder is preferably in the range of 10 to 20% by mass, particularly preferably in the range of 12 to 19% by mass, based on the wet process silica. When alumina hydrate is used for the ink receiving layer, the ratio of the hydrophilic binder is preferably in the range of 10 to 20% by mass, particularly preferably in the range of 12 to 19% by mass with respect to the alumina hydrate.

  For the ink-receiving layer, there are further hardening agents, colored dyes, colored pigments, ink dye fixing agents, UV absorbers, antioxidants, pigment dispersants, antifoaming agents, leveling agents, preservatives, fluorescent whitening agents. Various known additives such as viscosity stabilizers and pH adjusters can also be added.

The uppermost ink-receiving layer used in the present invention will be described in detail. The uppermost layer of the ink receiving layer of the present invention needs to contain colloidal silica. High scratch resistance, in order to keep the ink absorbability, the amount of the colloidal silica in the uppermost layer is preferably from ^{0.25g / m 2 ~5g / m 2} , more preferably 0.5g / m ² ~3g / m ² It is.

  Colloidal silica is a product obtained by dispersing silicon dioxide obtained by heating and aging a silica sol obtained through metathesis by an acid of sodium silicate or the like through an ion exchange resin layer in a colloidal form, and an average primary particle size is 5 to 5. 100 nm, preferably 10 to 60 nm, more preferably 2 to 60 nm is preferable from the viewpoint of ink absorptivity. Two kinds of colloidal silica having an average primary particle size of 5 to 100 nm and different average primary particle diameters may be used in combination. Examples of commercially available spherical products include Nissan Chemical Industries, Ltd., Snowtex 20, Snowtex 20L, etc., Catalyst Chemical Industry Co., Ltd., Cataloid USB, etc. ), Snowtex UP, Snowtex OUP, and pearl necklaces include Nissan Chemical Industries, Ltd., Snowtex PS-M, and the like.

  The hydrophilic binder used for the uppermost layer of the present invention will be described. The hydrophilic binder mentioned above is used for the uppermost layer of this invention. Preferred hydrophilic binders include fully or partially saponified polyvinyl alcohol or gelatin. Particularly preferred is a partially saponified polyvinyl alcohol having a saponification degree of 80% or more, and an average polymerization degree of 200-5000 is preferred.

  The ratio of the hydrophilic binder in the uppermost layer is preferably 3 to 25% by mass and more preferably 5 to 18% by mass with respect to the colloidal silica. More preferably, it is the range of 7-15 mass% with respect to colloidal silica.

  The ink jet recording material of the present invention contains a hydrazine derivative in the ink receiving layer described above. The hydrazine derivative used in the present invention is preferably represented by the following chemical formula 1.

In Formula 1, R _{1 to} R ₄ are independently a hydrogen atom, a substituted or unsubstituted aliphatic group, aromatic group, heterocyclic group, carbonyl group, thiocarbonyl group, sulfonyl group, sulfoxy group, phosphoryl group, imino. Represents a methylene group or the like, which may be linked to form a ring, or may be a polymer;

  Examples of the substituent include an alkyl group, an aryl group, a heterocyclic group, an alkoxy group, an amino group, a hydrazino group, a carbonyl group, and a carbamoyl group. These substituents further have another substituent. It may be.

A hydrazine derivative having a substituted or unsubstituted carbonyl group or sulfonyl group in at least one of R _{1 to} R ₄ is preferable. In particular, in terms of storability and ink absorption of printed images, at least one of R _{1 to} R ₄ is a hydrazine derivative having a carbamoyl group and a semicarbazide structure, and at least one of R _{1 to} R ₄ is a hydrazinocarbonyl group and is a carbohydrazide. A hydrazine derivative having a structure is preferred. Furthermore, it is more preferable that R ₁ and R ₂ are alkyl groups, and R ₃ or R ₄ is a carbamoyl group or a hydrazinocarbonyl group. Examples of the hydrazine derivative used in the present invention include the following compounds.

Content of the inkjet recording material of the hydrazine derivative of the present invention is preferably from 0.1 to 50 mmol / m ^2, more preferably 0.2 to 20 mmol / m ^2.

  Examples of the method for incorporating the hydrazine derivative of the present invention into the ink receiving layer include, for example, a method of adding these derivatives to the ink receiving layer coating solution, and a solution containing the hydrazine derivative in the ink receiving layer previously provided on the support. There are a method of coating, a method of adding a hydrazine derivative to a slurry of inorganic fine particles, and then adding another additive to form a coating solution on a support.

  The hydrazine derivative of the present invention may be contained in any layer constituting the ink jet recording material, and when there are a plurality of ink receiving layers, it may be contained in any one layer or in a plurality of layers. Also good. It is preferably contained in an ink receiving layer other than the uppermost layer, and the uppermost ink receiving layer is preferably substantially not contained. Here, “substantially not contained” means not contained in the constituent coating liquid. Inclusion in an ink receiving layer other than the uppermost layer achieves a higher level of ink absorbability.

  In the present invention, another ink receiving layer is provided on the opposite surface (B surface) of the support to the above-described ink receiving layer, and can be used for postcard applications. In this case, the A side having excellent scratch resistance is used as an address side that may be damaged by handling with a printing press. As the ink receiving layer on the opposite surface (B surface), it is preferable to provide an ink receiving layer mainly containing inorganic fine particles having an average secondary particle diameter of 500 nm or less.

For the ink receiving layer on the opposite side (B side), the above-mentioned vapor phase method silica, finely pulverized wet silica, and alumina hydrate are preferably used as inorganic fine particles. Further, the coating amount of the inorganic fine particles in the ink receiving layer is required to be 10 g / m ² or more, preferably 15 g / m ² or more, more preferably 17 g / m ² or more. The upper limit is about 40 g / m ² .

  The hydrophilic binder described above is used for the ink receiving layer on the opposite surface (B surface). Preferred hydrophilic binders include fully or partially saponified polyvinyl alcohol or gelatin. Particularly preferred is a partially saponified polyvinyl alcohol having a saponification degree of 80% or more, and an average polymerization degree of 200-5000 is preferred.

  A preferred range of the ratio of the hydrophilic binder in the ink receiving layer on the opposite surface (B surface) is appropriately selected depending on the type of inorganic fine particles used. When vapor phase method silica is used for the ink receiving layer, the ratio of the hydrophilic binder is preferably 15 to 30% by mass, more preferably 16 to 27% by mass, particularly 17 to 25%, relative to the vapor phase method silica. A range of mass% is preferred. When wet process silica is used for the ink receiving layer, the ratio of the hydrophilic binder is preferably in the range of 10 to 20% by mass, particularly preferably in the range of 12 to 19% by mass, based on the wet process silica. When alumina hydrate is used for the ink receiving layer, the ratio of the hydrophilic binder is preferably in the range of 10 to 20% by mass, particularly preferably in the range of 12 to 19% by mass with respect to the alumina hydrate.

  In the ink receiving layer on the opposite side (B side), a hardening agent, coloring dye, coloring pigment, ink dye fixing agent, ultraviolet absorber, antioxidant, pigment dispersing agent, antifoaming agent, leveling agent, Various known additives such as preservatives, optical brighteners, viscosity stabilizers, pH adjusters and the like can also be added.

  In the present invention, an arbitrary method is used as a method of applying the A-side and B-side ink-receiving layers. When two or more ink-receiving layers are simultaneously applied, for example, a slide bead method, a curtain method, and an extrusion method are used. There are methods, and in the case of continuous application, it can be applied continuously by a combination of the above methods, an air knife method, a roll coating method, a rod bar coating method, and the like and the above application methods. In the present invention, simultaneous application means that the respective layers are applied almost simultaneously, and continuous application means that the upper layer is continuously applied in a short time (usually within about 10 seconds) without a drying step after the lower layer application. In view of the uniformity of the ink receiving layer, simultaneous application is preferred.

  Examples of the present invention will be described below, but the present invention is not limited to these examples. Further, “parts” and “%” shown in the examples represent parts by mass and mass% of the solid content unless otherwise specified.

Example 1
<Preparation of polyolefin resin-coated paper support>
A 1: 1 mixture of hardwood bleached kraft pulp (LBKP) and softwood bleached sulfite pulp (NBSP) was beaten to 300 ml with Canadian Standard Freeness to prepare a pulp slurry. As a sizing agent, alkylketene dimer is 0.5% to pulp, polyacrylamide is 1.0% to pulp, and cationized starch is 2.0% to pulp. Polyamide epichlorohydrin resin is 0 to pulp. 0.5% was added and diluted with water to make a 1% slurry. This slurry was made with a long paper machine to a basis weight of 160 g / m ² , dried and conditioned to obtain a polyolefin resin-coated paper base paper. A polyethylene resin composition in which 10% of anatase-type titanium oxide is uniformly dispersed with respect to a resin of 100% of low density polyethylene having a density of 0.918 g / cm ³ is melted at 320 ° C. on the base paper thus produced, and the thickness is 25 μm. Then, both sides of the base paper were extrusion-coated, and a resin-coated paper layer was provided by extrusion coating using a cooling roll having a finely roughened surface.

The polyolefin resin-coated paper was subjected to high-frequency corona discharge treatment on both sides, and then an undercoat layer having the following composition was applied and dried so that the gelatin content was 50 mg / m ² to prepare a polyolefin resin-coated paper support.

<Underlayer>
Lime-processed gelatin 100 parts Sulfosuccinic acid-2-ethylhexyl ester salt 2 parts Chrome alum 10 parts

The above-mentioned polyolefin resin-coated paper support is coated with an ink-receiving layer a having the following composition as an ink-receiving layer as a lower layer close to the support, with a coating amount of 22 g / m ² in solid content, and with an ink-receiving layer b blended as the uppermost layer. The ink-receiving layer was provided by coating and drying so that the coating amount was 1 g / m ² in terms of solid content, and the ink jet recording material of Example 1 was produced.

<Ink-receiving layer a formulation>
Gas phase method silica dispersion (as solid content of gas phase method silica) 100 parts (average primary particle diameter 7 nm, specific surface area 300 m ² / g by BET method)
Boric acid 3 parts polyvinyl alcohol 20 parts (saponification degree 88%, average polymerization degree 3500)
Compound (25) of the present invention 3 parts Surfactant 0.3 part

<Ink-receiving layer b formulation>
Colloidal silica 100 parts (manufactured by Nissan Chemical Industries, Snowtex ST-OL40, average primary particle size 40-50 nm)
10 parts of polyvinyl alcohol (saponification degree 88%, average polymerization degree 3500)
Compound (25) of the present invention 4 parts Surfactant 1 part

The vapor phase silica dispersion was prepared as follows. Add 4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight 9,000) and 100 parts of vapor phase silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g by BET method) to water, and kneading equipment (specialized machine) Kneaded for 60 minutes using a Hibismix manufactured by Kogyo Co., Ltd. to obtain a gas phase silica crude dispersion. This crude vapor phase silica dispersion was dispersed with a high-pressure homogenizer to obtain a vapor phase silica dispersion. The average secondary particle size at this time was 130 nm.

(Example 2)
An ink jet recording material of Example 2 was produced in the same manner as in Example 1 except that the compound (25) of the present invention was removed from the formulation of the ink receiving layer b in the ink jet recording material of Example 1.

(Example 3)
The ink jet recording material of Example 3 was produced in the same manner as in Example 1 except that the compound (25) of the present invention was removed from the ink receiving layer a formulation in the ink jet recording material of Example 1.

Example 4
In the inkjet recording material of Example 1, the same procedure as in Example 1 was conducted except that the compound (25) of the present invention having the ink-receiving layer a and b was replaced with the compound (5) of the present invention. An ink jet recording material was prepared.

(Examples 5-7)
In the ink jet recording materials of Examples 1 to 3, the coating amount of the ink receiving layer a described above as the ink receiving layer on the surface (address surface) opposite to the surface (addressed surface) coated with the ink receiving layer is 22 g / in solid content. Ink-jet recording materials for postcard applications of Examples 5 to 7 were produced in the same manner as in Examples 1 to 3, except that the ink receiving layer was provided by coating and drying on m ² .

(Comparative Example 1)
The inkjet recording material of Comparative Example 1 was prepared in the same manner as in Example 1 except that the compound (25) of the present invention was removed from the formulation of the ink receiving layer a and b in the inkjet recording material of Example 1.

(Comparative Example 2)
An ink jet recording material of Comparative Example 2 was produced in the same manner as in Example 1 except that the ink receiving layer b was removed from the ink jet recording material of Example 1.

(Comparative Example 3)
The inkjet recording material of Comparative Example 3 was produced in the same manner as in Comparative Example 2 except that the compound (25) of the present invention was removed from the ink-receiving layer a formulation in the inkjet recording material of Comparative Example 2.

(Comparative Examples 4 and 5)
In the ink jet recording materials of Comparative Examples 1 and 2, the ink receiving layer a was applied at a solid content of 15 g / m ² (addressed surface), and the surface opposite to the surface on which the ink receiving layer was applied (communication surface) was used as the ink receiving layer. Ink jet recording of Comparative Examples 4 and 5 in the same manner as Comparative Examples 1 and 5, except that the ink receiving layer a blended above was applied to a solid content of 22 g / m ² and dried to provide an ink receiving layer. The material was made.

  The ink jet recording materials of Examples 1 to 7 and Comparative Examples 1 to 5 were evaluated by the following methods, and the results are shown in Table 1.

<Evaluation of ink absorbency>
A black solid image is printed on the obtained inkjet recording material with an inkjet printer (PM970C: manufactured by Seiko Epson Corporation) under the conditions of 20 ° C. and 65% RH, and after 30 seconds, PPC paper is overlaid on the printing surface and lightly pressed. The ink was then peeled off and the ink show-through on the PPC paper was evaluated according to the following criteria.
○: There is no show-through.
Δ: Slightly show-through
×: There is clearly show-through.

<Scratch resistance evaluation>
The surface of the obtained inkjet recording material (double-sided coated product is the addressed surface) was scratched using a scratch tester (Gardner hardness meter, manufactured by Toyo Seiki Co., Ltd.) and evaluated according to the following criteria.
○: Not scratched.
Δ: Some surface scratches.
×: Scratches are severe.

<Blanket dirt evaluation>
In the obtained double-sided inkjet recording material for postcard use, 1000 postal code frames were printed on the address side with a printing machine (Diamond 3H-4, manufactured by Mitsubishi Heavy Industries, Ltd.), and blanket stains were judged according to the following criteria.
○: The blanket is not dirty and there is no problem.
Δ: Some dirt is seen on the blanket, and there is a possibility that it becomes a problem when the number of sheets increases.
X: It is a level in which a considerable blanket stain is seen with 1000 sheets and becomes a problem.

  From Table 1, it has an ink receiving layer mainly containing inorganic fine particles having an average secondary particle diameter of 500 nm or less on one side of a water-resistant support, and contains colloidal silica as an uppermost layer on the ink receiving layer. In the ink jet recording material provided with the ink receiving layer, it can be seen that the ink jet recording materials of Examples 1 to 4 containing a hydrazine derivative in the ink receiving layer are ink jet recording materials excellent in ink absorbability and scratch resistance. It can be seen that Example 2 which does not contain a hydrazine derivative in the uppermost layer is particularly excellent in ink absorbability. On the other hand, the ink jet recording material of Comparative Example 1 that does not contain a hydrazine derivative in the ink-receiving layer is significantly inferior in ink absorbability, and the ink jet recording materials of Comparative Examples 2 and 3 that do not have the uppermost layer containing colloidal silica are scratch resistant. It was inferior result.

  In addition, the ink jet recording materials of Examples 5 to 7 provided with an ink jet receiving layer on both sides for postcard use were excellent because blanket stains did not occur during printing on the address side postal code frame. On the other hand, the ink jet recording material of Comparative Example 4 which did not contain a hydrazine derivative in the ink receiving layer had poor ink absorbability and had practical problems. The inkjet recording material of Comparative Example 4 having no uppermost layer containing colloidal silica resulted in blanket stains occurring when printing on the address side postal code frame, resulting in a significant loss of productivity.

Claims (5)

  At least two layers having an ink receiving layer mainly containing inorganic fine particles having an average secondary particle diameter of 500 nm or less and an ink receiving layer containing colloidal silica as the uppermost layer on one surface (A surface) of the water-resistant support. An ink jet recording material having an ink receiving layer, wherein at least one of the ink receiving layers contains a hydrazine derivative.   The ink jet recording material according to claim 1, wherein the uppermost ink receiving layer contains substantially no hydrazine derivative.   The inkjet recording material according to claim 1, wherein the water-resistant support is a resin-coated paper.   The inkjet recording according to any one of claims 1 to 3, further comprising an ink receiving layer mainly containing inorganic fine particles having an average secondary particle diameter of 500 nm or less on the opposite surface (B surface) of the water-resistant support. material.   An ink jet recording material, wherein the ink jet recording material according to claim 4 is used for postcards.