JP2016190407A - Method for production of inkjet recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for production of an inkjet recording material capable of obtaining a stable coating film without lowering the surface quality of an ink reception layer even when applying a coating liquid over a long time.SOLUTION: There is provided a method for production of an inkjet recording material having on a substrate, the ink reception layer containing inorganic fine particles as a main constituent. The method is characterized by continuously making a coating liquid containing at least the inorganic fine particles and a water-soluble binder pass through two or more filters when applying on the substrate, and by making a pressure loss to be 0.03 MPa or more when passing through the filters.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing an ink jet recording material having an ink receiving layer mainly containing inorganic fine particles. More specifically, the present invention relates to a method for manufacturing an ink jet recording material that can be stably applied.

  As a recording material used in the ink jet recording system, a porous ink receiving layer, which is called an ink jet recording paper, comprising a pigment such as amorphous silica and a water-soluble binder such as polyvinyl alcohol is provided on a support. Recording materials are known.

  In recent years, recording materials using ultrafine inorganic fine particles as a pigment and having a photo-like gloss have been known. For example, it has been proposed to use inorganic ultrafine particles such as gas phase method silica or wet method silica, whose secondary particle size is pulverized and dispersed to 500 nm or less, as a pigment component of the ink receiving layer (for example, gas phase method silica As examples of use, JP-A-10-119423, JP-A-2000-21235, JP-A-2000-309157, and examples of use of pulverized sedimentation silica include JP-A-9-286165 and JP-A-10-181190. JP, 2001-277712, etc.) as an example of using the pulverized gel method silica. Also, recording materials using alumina or alumina hydrate as inorganic ultrafine particles other than silica have been proposed (for example, Japanese Patent Laid-Open Nos. 62-174183, 2-276670, and 5- 32037, JP-A-6-199034, etc.). The ink receiving layer containing extremely fine inorganic fine particles as described above is quick-drying because it absorbs ink into the voids of the inorganic fine particles, and is a technique commonly used in recent inkjet recording materials. When the ink receiving layer mainly contains inorganic fine particles, the ink receiving layer becomes a porous ink receiving layer having a high porosity, and the ink absorbability is further improved.

  On the other hand, in general, in the production of an ink jet recording material, a coating liquid is continuously applied to a support wound in a long roll shape. In order to increase production efficiency, it is preferable to produce a large amount of coating solution at a time and apply it continuously. Therefore, the coating solution manufactured at one time is applied to the support over a long time. For example, it may exceed 5 hours or even 10 hours. Until the coating liquid is prepared and the coating is completed, the coating liquid is kept at a temperature of about 30 to 45 ° C. and held. However, when the ratio of the inorganic fine particles contained in the coating solution is high, the viscosity of the coating solution tends to increase with the passage of time, and this phenomenon is particularly caused when inorganic fine particles having an average secondary particle size of 500 nm or less are used. Appears prominently. Therefore, conventionally, the manufactured coating solution has to be used up until the viscosity of the coating solution increases and the surface quality of the ink receiving layer starts to deteriorate, and the adjustment is complicated.

  On the other hand, in Japanese Patent Application Laid-Open No. 2000-015927 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2007-99586 (Patent Document 2), a coating liquid containing inorganic fine particles having a specific particle diameter is filtered through a filter. , Removing coarse particles in the coating solution. Japanese Patent Laid-Open No. 2005-58833 (Patent Document 3) describes the pressure loss of the downstream pipe from the ultrasonic defoamer to the coater inlet in the liquid feed path from the liquid feed tank to the coating coater inlet, and the downstream side. It is described that the re-foaming of bubbles dissolved by the ultrasonic defoaming device is prevented by setting the change in the internal pressure of the piping to a specific range. Japanese Patent Application Laid-Open No. 2005-66831 (Patent Document 4) By treating the ink-receiving layer coating liquid containing inorganic fine particles with a filter having a filtration accuracy of 5 to 100 μm, and setting the filter passage amount at that time within a specific range, and further applying within 50 hours after the filter treatment, It is described that bleeding of an image with the passage of time after printing can be improved.

JP 2000-15927 A Japanese Patent Laid-Open No. 2007-99586 JP 2005-58833 A JP 2005-66831 A

  An object of the present invention is to reduce the surface quality of an ink receiving layer when a coating solution is applied over a long period of time in a method for producing an ink jet recording material having an ink receiving layer mainly containing inorganic fine particles on a support. It is an object of the present invention to provide a method for producing an ink jet recording material which can be stably applied without the need for the above.

The above object has been achieved by the following invention.
1) A method for producing an ink jet recording material having an ink receiving layer mainly containing inorganic fine particles on a support, wherein the coating liquid containing at least inorganic fine particles and a water-soluble binder is applied on the support. A method for producing an inkjet recording material, wherein the coating solution is continuously passed through two or more filters, and the pressure loss when the coating solution is passed through the filters is 0.03 MPa or more.

  According to the present invention, it is possible to provide a method for producing an ink jet recording material which can be stably applied without deteriorating the surface quality of the ink receiving layer when the coating liquid is applied for a long time.

  Hereinafter, the present invention will be described in detail. In the method for producing an ink jet recording material of the present invention, when a coating liquid containing at least inorganic fine particles and a water-soluble binder is coated on a support, the coating liquid is continuously passed through two or more filters, and the filter Is set to 0.03 MPa or more.

  To achieve a pressure loss of 0.03 MPa or higher when passing through the filter, the filtration accuracy of the filter used (an index indicating that 99.5% or more of particles larger than the displayed filtration accuracy can be removed) And the amount of coating solution fed to the filter can be combined with ease. The upper limit of the pressure loss when the filter is passed is preferably 0.20 MPa or less.

  The filtration accuracy of the filter is preferably in the range of 15 to 250 μm. The filter used in the present invention can be any filter having such a filtration accuracy, such as a depth filter (a “wound type” in which a yarn is wound around a core, a “nonwoven fabric lamination in which a nonwoven fabric is wound around a cylindrical core) Type ”,“ resin molding type ”which is a resin molded product in the form of sponge, etc., and surface filters (for example, filter media, wire mesh, filter paper, precision filtration membrane processed into pleats, hollow fiber membranes, etc.) Any of these (included in this type) can be used. Examples of commercially available products include TCPD type manufactured by Advantech, beta pure and polypro clean manufactured by Cuno, filters manufactured by Nippon Pole Co., Ltd., and process filters manufactured by Yamashin Filter Co., Ltd., which are obtained and used. It is also possible. Moreover, as a liquid feeding amount of the coating liquid to a filter, the range of 12-25 L / min is preferable.

  The filter used in the present invention requires at least two or more filters, and allows the coating liquid to pass through two or more filters continuously (in the liquid feeding path, at least two filters are connected in series to form the coating liquid. Pass through). In that case, it is preferable that the filter is mounted in a commercially available housing and used by connecting it. When only one filter is used, it is impossible to improve the deterioration of the surface quality of the ink receiving layer when the coating liquid is applied for a long time. The upper limit is not particularly limited, but if it is too much, a certain effect cannot be obtained, so it is preferably 5 or less. When four or more filters are used, for example, two filters connected in series in the liquid feeding path can be connected in parallel.

  As a position where two or more filters are continuously provided in the liquid feeding path, all the components contained in the ink receiving layer are added to the coating liquid (for example, a cationic compound in a liquid containing inorganic fine particles). Or after the in-line addition of a hardener or the like, and preferably after the defoaming treatment is completed. Thereafter, the coating liquid that has passed through the plurality of filters is supplied to a coating apparatus and coated on the support.

  The ink jet recording material obtained by the present invention has at least one ink receiving layer mainly containing inorganic fine particles. Here, “mainly containing inorganic fine particles” means that the inorganic fine particles are contained in an amount of 50% by mass or more, more preferably 60% by mass or more, and particularly preferably 65% by mass with respect to the total solid content in the ink receiving layer. The upper limit is about 95% by mass.

  Examples of the inorganic fine particles used in the ink receiving layer in the invention include various known fine particles such as amorphous synthetic silica, alumina, alumina hydrate, calcium carbonate, magnesium carbonate, and titanium dioxide. Amorphous synthetic silica, alumina or alumina hydrate is preferred from the standpoint of clarity.

  Amorphous synthetic silica can be roughly classified into wet method silica, gas phase method silica, and others depending on the production method. 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, and the silica particles that have grown are agglomerated and settled, and are then commercialized through the steps of filtration, washing, drying, pulverization and classification. Precipitated silica is commercially available, for example, from Tosoh Silica Co., Ltd. as a nip seal and from Tokuyama Co., Ltd. as a Toxeal. Gel silica is produced by reacting sodium silicate and sulfuric acid under acidic conditions. During the ripening, the fine particles dissolve and reprecipitate so as to bind other primary particles, so that the distinct primary particles disappear and form relatively hard aggregated particles having an internal void structure. For example, it is commercially available as nip gel from Tosoh Silica Co., Ltd. and as syloid and silo jet from Grace Japan Co., Ltd. The sol method silica is also called colloidal silica, which is obtained by heating and aging a silica sol obtained through metathesis of sodium silicate acid or the like through an ion exchange resin layer. For example, it is commercially available as Snowtex from Nissan Chemical Industries, Ltd. Yes.

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

In the present invention, gas phase method silica can be preferably used. The average primary particle diameter of the vapor phase silica used in the present invention is preferably 30 nm or less. More preferably, an average primary particle diameter of 3 to 15 nm (especially 3 to 10 nm) and a specific surface area by the BET method of 200 m ² / g or more (preferably 250 to 500 m ² / g) are used. In addition, the average primary particle diameter referred to in the present invention is an average value obtained by taking the diameter of a circle equal to the projected area of each of 100 primary particles existing within a certain area by observation with an electron microscope as a particle diameter. It is. The BET method referred to in the present invention is one of the powder surface area measurement methods by the vapor phase adsorption method, and is a method for obtaining the total surface area, that is, the specific surface area of a 1 g sample from the adsorption isotherm. Usually, as the adsorbed gas, a large amount of nitrogen gas is used, and the method of measuring the amount of adsorption from the change in pressure or volume of the gas to be adsorbed is most often used. The most prominent expression for expressing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller formula, called the BET formula, 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.

  As the vapor phase method silica, those dispersed in the presence of a cationic compound can be preferably used. The average secondary particle size of the vapor phase method silica is preferably 500 nm or less, more preferably 10 to 300 nm. As a dispersion method, gas phase method silica and a dispersion medium are premixed by ordinary propeller stirring, turbine type stirring, homomixer type stirring, etc., and then a media mill such as a ball mill, a bead mill, a sand grinder, a high pressure homogenizer, an ultrahigh pressure, etc. It is preferable to perform dispersion using a pressure disperser such as a homogenizer, an ultrasonic disperser, a thin film swirl disperser, or the like. The average secondary particle diameter as used in the present invention can be determined by photography using a transmission electron microscope. For simplicity, a laser scattering particle size distribution meter (for example, LA920 manufactured by Horiba, Ltd.) Can be measured as a number median diameter.

  In the present invention, wet process silica is also preferably used. As the wet method silica used here, precipitation method silica or gel method silica is preferable, and precipitation method silica is particularly preferable. The wet process silica particles used in the present invention are preferably wet process silica particles having an average primary particle diameter of 50 nm or less, preferably 3 to 40 nm, and an average secondary particle diameter of 500 nm or less, and more preferably an average secondary particle. It is preferable to use wet method silica fine particles having a particle diameter of 20 to 300 nm.

  The wet process silica is preferably dispersed and pulverized in the presence of a cationic compound. As a pulverization method, a wet dispersion method in which silica dispersed in an aqueous medium is mechanically pulverized can be preferably used. A preferred method for pulverizing the wet process silica fine particles used in the present invention will be described. First, silica particles and a cationic compound are mixed in a dispersion medium mainly composed of water, and at least one dispersion device such as a sawtooth blade type dispersion machine, a propeller blade type dispersion machine, or a rotor stator type dispersion machine is used. Use to obtain a silica pre-dispersion. If necessary, an appropriate low boiling point solvent or the like may be added to the aqueous dispersion medium. The higher the solid content concentration of the silica pre-dispersion liquid, the more preferable, but when the concentration is too high, it becomes impossible to disperse, so the preferable range is 15 to 40% by mass, and more preferably 20 to 35% by mass. Next, the silica pre-dispersion is subjected to mechanical means having a stronger shearing force to pulverize the silica particles, whereby a wet process silica fine particle dispersion is obtained. As a mechanical means, a known method can be adopted, for example, a media mill such as a ball mill, a bead mill, a sand grinder, a high pressure homogenizer, a pressure disperser such as an ultra high pressure homogenizer, an ultrasonic disperser, a thin film swirl disperser, etc. Can be used.

  As the cationic compound used for the dispersion of the gas phase method silica and the wet method silica, a cationic polymer can be preferably used. As the cationic polymer, polyethyleneimine, polydiallylamine, polyallylamine, alkylamine polymer, JP-A 59-20696, JP-A 59-33176, JP-A 59-33177, JP 59-1555088, JP 60-11389, JP 60-49990, JP 60-83882, JP 60-109894, JP 62-198493 JP-A-63-49478, JP-A-63-115780, JP-A-63-280681, JP-A-1-40371, JP-A-6-234268, JP-A-7-125411 A polymer having a primary to tertiary amino group or a quaternary ammonium base described in JP-A-10-193976 Used Mashiku. In particular, diallylamine derivatives are preferably used as the cationic polymer. In terms of dispersibility and dispersion viscosity, the weight average molecular weight of these cationic polymers is preferably about 2000 to 100,000, and more preferably about 2000 to 30,000.

  As the alumina used in the present invention, γ-alumina which is a γ-type crystal of aluminum oxide is preferable, and among them, a δ group crystal is preferable. γ-alumina can make primary particles as small as about 10 nm. Usually, secondary particles of several thousand to several tens of thousands nm are pulverized with ultrasonic waves, high-pressure homogenizers, opposed collision type jet pulverizers, etc. Can be used. The average secondary particle diameter of alumina is preferably 500 nm or less, more preferably 20 to 300 nm.

The alumina hydrate used in the present invention is represented by a constitutive formula of Al ₂ O ₃ .nH ₂ O (n = 1 to 3). The alumina hydrate used in the present invention can be obtained by a known production method such as hydrolysis of aluminum alkoxide such as aluminum isopropoxide, neutralization of aluminum salt with alkali, hydrolysis of aluminate, and the like. The average secondary particle size of the alumina hydrate used in the present invention is preferably 500 nm or less, more preferably 20 to 300 nm.

  As the above-described alumina and alumina hydrate used in the present invention, those dispersed by a known dispersant such as acetic acid, lactic acid, formic acid, nitric acid and the like are preferably used.

  Two or more kinds of inorganic fine particles may be used in combination from the inorganic fine particles described above. For example, combined use of finely divided wet method silica and vapor phase method silica, combined use of finely divided wet method silica and alumina or alumina hydrate, and combined use of vapor phase method silica and alumina or alumina hydrate. It is done.

The dry coating amount of the ink receiving layer in the present invention is preferably 8 to 40 g / m ^{2 and} particularly preferably 10 to 30 g / m ² as the solid content of the inorganic fine particles.

  The ink receiving layer coating liquid of the present invention contains a water-soluble binder. As the water-soluble binder, polyvinyl alcohol, polyethylene glycol, starch, dextrin, carboxymethyl cellulose, polyvinyl pyrrolidone, polyacrylic acid ester and derivatives thereof are used, and among them, completely or partially saponified polyvinyl alcohol is preferred, A saponification degree of 80% or more is particularly preferable. Moreover, 500-6000 are preferable and, as for the average degree of polymerization of polyvinyl alcohol, 1000-5000 are more preferable.

  Examples of the polyvinyl alcohol include cation-modified polyvinyl alcohol, anion-modified polyvinyl alcohol, silanol-modified polyvinyl alcohol, and other polyvinyl alcohol derivatives in addition to general polyvinyl alcohol. Polyvinyl alcohol may be used alone or in combination of two or more.

  The content of the water-soluble binder in the ink receiving layer coating liquid of the present invention is preferably from 3 to 30% by mass, particularly preferably from 5 to 25% by mass, based on the inorganic fine particles.

  The ink receiving layer coating liquid of the present invention preferably contains a crosslinking agent together with a water-soluble binder. As the crosslinking agent, known crosslinking agents can be used. Specific examples include aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, bis (2-chloroethylurea), 2- Hydroxy-4,6-dichloro-1,3,5-triazine, a compound having a reactive halogen as described in US Pat. No. 3,288,775, divinyl sulfone, US Pat. No. 3,635,718 Compounds having reactive olefins as described in the specification, N-methylol compounds as described in US Pat. No. 2,732,316, isocyanates as described in US Pat. No. 3,103,437, Aziridine compounds as described in U.S. Pat. Nos. 3,017,280 and 2,983,611, Carbodiimide compounds as described in US Pat. No. 3,100,704, epoxy compounds as described in US Pat. No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, There are inorganic crosslinking agents such as chromium alum, zirconium sulfate, boric acid, borate, borax, and the like, and these can be used alone or in combination of two or more. Among these, boric acid or borate is particularly preferable. The addition amount of the crosslinking agent is preferably 0.1 to 40% by mass, more preferably 0.5 to 30% by mass with respect to the water-soluble binder constituting the ink receiving layer.

  The ink image-receiving layer can contain a cationic compound for the purpose of increasing the water resistance of the ink-receiving layer. These cationic compounds can be added in-line to a liquid containing inorganic fine particles and a water-soluble binder immediately before coating.

  Examples of the cationic compound include a cationic polymer and a water-soluble metal compound. As the cationic polymer, polyethyleneimine, polydiallylamine, polyallylamine, alkylamine polymer, JP-A 59-20696, JP-A 59-33176, JP-A 59-33177, JP 59-1555088, JP 60-11389, JP 60-49990, JP 60-83882, JP 60-109894, JP 62-198493 JP-A-63-49478, JP-A-63-115780, JP-A-63-280681, JP-A-1-40371, JP-A-6-234268, JP-A-7-125411 A polymer having a primary to tertiary amino group or a quaternary ammonium base described in JP-A-10-193976 Used Mashiku. The molecular weight of these cationic polymers is preferably 5,000 or more, and more preferably about 5,000 to 100,000. The content of these cationic polymers is preferably 1 to 10% by weight based on the inorganic fine particles.

  Examples of the water-soluble metal compound used in the present invention include water-soluble polyvalent metal salts. Examples include water-soluble salts of metals selected from calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, chromium, magnesium, tungsten, and molybdenum. 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 Cupric, ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, sulfuric acid Nickel ammonium hexahydrate, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, ferrous bromide, chloride Ferrous, ferric chloride, ferrous sulfate, ferric sulfate, zinc bromide, zinc chloride, zinc nitrate six Japanese, Zinc sulfate, Zirconium acetate, Zirconium chloride, Zirconium chloride octahydrate, Hydroxy zirconium chloride, Chromium acetate, Chromium sulfate, Magnesium sulfate, Magnesium chloride hexahydrate, Magnesium citrate nonahydrate, Phosphorus tungsten Sodium tungstate, sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, and the like.

  In the present invention, a water-soluble aluminum compound or a water-soluble compound containing a Group 4A element of the periodic table is particularly preferable in terms of water resistance, weather resistance, and prevention of cracking of inorganic fine particles. As the water-soluble aluminum compound, for example, aluminum chloride or its hydrate, aluminum sulfate or its hydrate, ammonium alum and the like are known as inorganic salts. Furthermore, there is a basic polyaluminum hydroxide compound which is an inorganic aluminum-containing cationic polymer. In particular, a basic polyaluminum hydroxide compound is preferable.

The basic polyaluminum hydroxide compound has a main component represented by the following general formula 1, 2 or 3, for example, [Al ₆ (OH) ₁₅ ] ³⁺ , [Al ₈ (OH) ₂₀ ] ⁴⁺ , [Al ₁₃ (OH) ₃₄ ] ⁵⁺ , [Al ₂₁ (OH) ₆₀ ] ^{3+ and} the like are water-soluble polyaluminum hydroxides stably containing a basic and high-molecular polynuclear condensed ion.

[Al ₂ (OH) _n Cl _6-n ] _m General formula 1
[Al (OH) ₃ ] _n AlCl ₃ General formula 2
Al _n (OH) _m Cl _(3n-m) 0 <m <3n General formula 3

  These are water treatment agents from Taki Chemical Co., Ltd. under the name of polyaluminum chloride (PAC), from Asada Chemical Co., Ltd. under the name of polyaluminum hydroxide (Paho), and from Riken Green Co., Ltd. It is marketed under the name of Purachem WT and from other manufacturers for the same purpose, and various grades are readily available.

  In the present invention, the content of the water-soluble aluminum compound in the ink receiving layer is preferably from 0.1 to 10% by mass, particularly preferably from 0.5 to 5% by mass, based on the inorganic fine particles.

  The ink receiving layer coating solution of the present invention further includes a surfactant, a fluorescent brightening agent, a coloring dye, a coloring pigment, an ink dye fixing agent, an ultraviolet absorber, an antioxidant, a pigment dispersant, an antifoaming agent. Various known additives such as additives, leveling agents, preservatives, and pH adjusters can be added.

  In addition to the ink receiving layer, the ink jet recording material of the present invention may be further provided with a layer having other functions such as a protective layer and a glossy layer.

  Non-absorbent supports such as polyethylene, polypropylene, polyvinyl chloride, diacetate resin, triacetate resin, cellophane, acrylic resin, polyethylene terephthalate, polyethylene naphthalate, and polyolefin resin-coated paper Absorbent supports such as high-quality paper, art paper, and coated paper are used. Among them, the non-absorbing support is preferable in that high gloss is obtained, but on the other hand, it does not absorb the solvent component in the ink. A porous ink receiving layer having excellent ink absorbability is preferably used on such a non-absorbing support, but the present invention is particularly useful for the ink jet recording material having such a configuration. The thickness of these supports is preferably about 50 to 300 μm.

  When using a film that is a non-absorbent support or an olefin resin-coated paper, activation treatment such as corona discharge treatment or flame treatment can be performed on the surface on which the ink receiving layer is provided.

  When a film or olefin resin-coated paper is used as the support, the support is preferably a support having an undercoat layer mainly composed of a natural polymer compound or a synthetic resin on the surface on which the ink receiving layer is provided. A support having an undercoat layer mainly composed of gelatin is preferred.

There is no particular restriction on the coating amount of the undercoat layer is preferably in the range of 0.005~2.0g / ^{m 2} in solid coating amount, more preferably in the range of 0.01 to 1.0 g / ^{m 2,} A range of 0.02 to 0.5 g / m ² is particularly preferred.

  Various back coat layers can be coated on the support in the present invention to prevent charging, improve transportability, prevent curling, and the like. The backcoat layer can contain an appropriate combination of inorganic and organic antistatic agents, hydrophilic binders, latexes, curing agents, pigments, surfactants and the like.

  In the present invention, the coating method is not particularly limited, and a known coating method can be used. For example, there are a slide bead method, a curtain method, an extrusion method, an air knife method, a roll coating method, a rod bar coating method, and the like. Among the coating methods, a slide bead method, a curtain method, and an extrusion method, which are pre-weighing types, are particularly preferably used.

  Examples of the present invention will be described below. In addition, a part and% show a mass part and the mass%.

Example 1
[Production of support]
A 1: 1 mixture of hardwood bleached kraft pulp (LBKP) and hardwood bleached sulfite pulp (LBSP) 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% added and diluted with water to give a 0.2% slurry. This slurry was made with a long paper machine to a basis weight of 170 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 is uniformly dispersed with respect to 100 parts of low density polyethylene resin having a density of 0.918 g / cm ³ is melted at 320 ° C. on a paper base paper having a density of 35 μm. Then, it was extrusion coated using a cooling roll that had been finely roughened and formed into a surface (ink-receiving layer-coated surface). Melted at similarly 320 ° C. The blend resin composition of the low density polyethylene resin 30 parts of a density 0.962 g / cm 70 parts high density polyethylene resin of ³ and a density 0.918 g / cm ³ on the other surface, the thickness Extrusion coating was carried out to a thickness of 30 μm, and extrusion coating was performed using a cooling roll that had been roughened to obtain a back surface.

After subjecting the surface of the polyolefin resin-coated paper to a high-frequency corona discharge treatment, an undercoat layer having the following composition was applied and dried so that the amount of gelatin adhered was 50 mg / m ² .
<Underlayer>
Gelatin 100 parts Sulfosuccinic acid-2-ethylhexyl ester salt 2 parts Chrome alum 8 parts

[Preparation of silica dispersion]
After adding 4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight: 9000) and 100 parts of gas phase method silica (average primary particle size: 7 nm, specific surface area of 300 m ² / g by BET method) to water to prepare a preliminary dispersion, A gas phase method silica dispersion having a solid concentration of 20% by mass was prepared by homogenizer treatment. The average secondary particle diameter of the vapor phase method silica was 130 μm.

<Ink-receiving layer coating solution 1>
Silica dispersion (as solids) 100 parts boric acid 4 parts polyvinyl alcohol (saponification degree 88%, average polymerization degree 3500) 22 parts basic polyaluminum hydroxide 2 parts sodium acetate 1.5 parts solid content concentration of coating solution 12 .5%

Example 1
The ink receiving layer coating liquid 1 was stored at 40 ° C. for 10 hours, and then defoamed. Thereafter, a pleated type filter with a filtration accuracy of 25 μm was mounted in the housing, and four of these were connected in series, and the amount of coating solution fed was passed under the condition of 19.0 L / min. The pressure loss when passing through the filter was 0.05 MPa. Thereafter, the ink receiving layer coating liquid 1 is fed into the slide bead coater, applied onto the undercoat layer of the polyolefin resin-coated paper obtained as described above, and cold air at 5 ° C. is blown to immobilize the coating liquid. Then, it was dried by blowing hot air of 50 ° C. The dry solid content of the ink receiving layer coating liquid 1 is 25 g / m ² . It was 330 mPa · s (25 ° C.) when the coating solution was sampled and its viscosity was measured immediately before entering the slide bead coater.

(Example 2)
The ink receiving layer coating liquid 1 was stored at 40 ° C. for 10 hours and then defoamed. Thereafter, a depth filter with a filtration accuracy of 175 μm was mounted in the housing, two of them were connected in series, and the amount of coating solution fed was passed under the condition of 19.0 L / min. The pressure loss when passing through the filter was 0.04 MPa. Thereafter, the ink receiving layer coating liquid 1 is fed into the slide bead coater, applied onto the undercoat layer of the polyolefin resin-coated paper obtained as described above, and cold air at 5 ° C. is blown to immobilize the coating liquid. Then, it was dried by blowing hot air of 50 ° C. The dry solid content of the ink receiving layer coating liquid 1 is 25 g / m ² . It was 340 mPa · s (25 ° C.) when the coating solution was collected and its viscosity was measured immediately before entering the slide bead coater.

Example 3
The ink receiving layer coating liquid 1 was stored at 40 ° C. for 10 hours, and then defoamed. Thereafter, a depth filter with a filtration accuracy of 175 μm was mounted in the housing, and four of these were connected in series, and the coating liquid feeding amount was passed under the condition of 19.0 L / min. The pressure loss when passing through the filter was 0.08 MPa. Thereafter, the ink receiving layer coating liquid 1 is fed into the slide bead coater, applied onto the undercoat layer of the polyolefin resin-coated paper obtained as described above, and cold air at 5 ° C. is blown to immobilize the coating liquid. Then, it was dried by blowing hot air of 50 ° C. The dry solid content of the ink receiving layer coating liquid 1 is 25 g / m ² . It was 335 mPa · s (25 ° C.) when the coating solution was collected and its viscosity was measured immediately before entering the slide bead coater.

Example 4
The ink receiving layer coating liquid 1 was stored at 40 ° C. for 10 hours, and then defoamed. Thereafter, a depth filter with a filtration accuracy of 75 μm was mounted in the housing, and two of these were connected in series, and the coating liquid feeding amount was passed under the condition of 19.0 L / min. The pressure loss when passing through the filter was 0.05 MPa. Thereafter, the ink receiving layer coating liquid 1 is fed into the slide bead coater, applied onto the undercoat layer of the polyolefin resin-coated paper obtained as described above, and cold air at 5 ° C. is blown to immobilize the coating liquid. Then, it was dried by blowing hot air of 50 ° C. The dry solid content of the ink receiving layer coating liquid 1 is 25 g / m ² . It was 330 mPa · s (25 ° C.) when the coating solution was sampled and its viscosity was measured immediately before entering the slide bead coater.

(Example 5)
The ink receiving layer coating liquid 1 was stored at 40 ° C. for 10 hours, and then defoamed. Thereafter, a depth filter with a filtration accuracy of 75 μm was mounted in the housing, and four of these were connected in series, and the coating liquid feeding amount was passed under the condition of 19.0 L / min. The pressure loss when passing through the filter was 0.14 MPa. Thereafter, the ink receiving layer coating liquid 1 is fed into the slide bead coater, applied onto the undercoat layer of the polyolefin resin-coated paper obtained as described above, and cold air at 5 ° C. is blown to immobilize the coating liquid. Then, it was dried by blowing hot air of 50 ° C. The dry solid content of the ink receiving layer coating liquid 1 is 25 g / m ² . It was 335 mPa · s (25 ° C.) when the coating solution was collected and its viscosity was measured immediately before entering the slide bead coater.

(Comparative Example 1)
The ink receiving layer coating liquid 1 was stored at 40 ° C. for 10 hours, and then defoamed. Thereafter, the ink receiving layer coating solution 1 is fed into the slide bead coater without passing through the filter, and applied onto the polyolefin resin-coated paper undercoating layer obtained above. After immobilizing the spray coating solution, hot air of 50 ° C. was sprayed and dried. The dry solid content of the ink receiving layer coating liquid 1 is 25 g / m ² . It was 380 mPa · s (25 ° C.) when the coating solution was collected and its viscosity was measured immediately before entering the slide bead coater.

(Comparative Example 2)
The ink receiving layer coating liquid 1 was stored at 40 ° C. for 10 hours, and then defoamed. Thereafter, a depth filter with a filtration accuracy of 175 μm was mounted in the housing, and the amount of coating liquid fed was passed through this one filter under the condition of 19.0 L / min. The pressure loss when passing through the filter was 0.02 MPa. Thereafter, the ink receiving layer coating liquid 1 is fed into the slide bead coater, applied onto the undercoat layer of the polyolefin resin-coated paper obtained as described above, and cold air at 5 ° C. is blown to immobilize the coating liquid. Then, it was dried by blowing hot air of 50 ° C. The dry solid content of the ink receiving layer coating liquid 1 is 25 g / m ² . It was 375 mPa · s (25 ° C.) when the coating solution was collected and its viscosity was measured immediately before entering the slide bead coater.

(Comparative Example 3)
The ink receiving layer coating liquid 1 was stored at 40 ° C. for 10 hours, and then defoamed. Thereafter, a depth filter with a filtration accuracy of 175 μm was mounted in the housing, two of them were connected in series, and the amount of coating liquid fed was passed under the condition of 7.5 L / min. The pressure loss when passing through the filter was 0.02 MPa. Thereafter, the ink receiving layer coating liquid 1 is fed into the slide bead coater, applied onto the undercoat layer of the polyolefin resin-coated paper obtained as described above, and cold air at 5 ° C. is blown to immobilize the coating liquid. Then, it was dried by blowing hot air of 50 ° C. The dry solid content of the ink receiving layer coating liquid 1 is 25 g / m ² . It was 340 mPa · s (25 ° C.) when the coating solution was collected and its viscosity was measured immediately before entering the slide bead coater.

(Evaluation of coating stability)
In order to confirm that stable application is possible without deteriorating the surface quality of the ink receiving layer when the coating liquid is applied over a long period of time, it was obtained as described above, immediately after production. An ink-jet recording material was prepared using the ink-receiving layer coating liquid 1, and the surface quality of the ink-jet recording material and the ink-jet recording material obtained using the ink-receiving layer coating liquid after storage at 40 ° C. for 10 hours The surface quality was compared as follows.

The ink receiving layer coating liquid 1 immediately after the preparation was applied onto the undercoat layer of the polyolefin resin-coated paper, and 5 ° C. cold air was blown to immobilize the coating liquid, and then 50 ° C. hot air was blown and dried. . The dry solid content of the ink receiving layer coating liquid 1 is 25 g / m ² . A fluorescent lamp was projected on the ink receiving layer of the ink jet recording material (reference sample) thus obtained, and when the reflected image was visually observed, the reflected image of the fluorescent lamp was clearly confirmed.

Using the image clarity of this reference sample as a standard product, the image clarity of the inkjet recording materials obtained in Examples 1 to 5 and Comparative Examples 1 to 3 was evaluated according to the following criteria. The results are shown in Table 1.
○: Same as standard product.
Δ: Slightly inferior to standard product, but at a good level.
X: Inferior to standard product.

  As is apparent from Table 1, according to the present invention, even when the coating liquid is applied over a long period of time, an ink jet recording material that can be stably applied without deteriorating the surface quality of the ink receiving layer is produced. It can be seen that a method is obtained.

Claims (1)

  A method for producing an ink jet recording material having an ink receiving layer mainly containing inorganic fine particles on a support, wherein the coating liquid is applied when a coating liquid containing at least inorganic fine particles and a water-soluble binder is applied on the support. Is a method for producing an ink jet recording material, wherein the pressure loss when the filter is passed through two or more filters continuously is 0.03 MPa or more.