JP2005280220A - Method for forming ink absorbing layer, and inkjet recording material using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently obtain an inkjet recording material, wherein an ink absorbing layer containing inorganic ultrafine particles as a main component is provided on a substrate, by forming the ink absorbing layer with good printing quality and with no crack on a coating layer. <P>SOLUTION: In this method for forming the ink absorbing layer, an ink-absorbing-layer coating liquid, wherein the inorganic ultrafine particles are contained as the main component, is applied to a substrate/dried on the substrate. The method for forming the ink absorbing layer, wherein the ink-absorbing-layer coating liquid is gelated by heating, comprises a step of heating/gelating the coating liquid in an atmosphere with a relative humidity of 70% or more after the application of the ink-absorbing coating liquid, and a step of heating/gelating the coating liquid in an atmosphere with a relative humidity of less than 70%, subsequently to the step. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for forming an ink receiving layer, and relates to an ink jet recording material used in a printer or plotter using the ink jet recording method using the forming method.

  The ink jet recording method is a method in which fine droplets of ink are ejected by various operating principles and adhered to a recording sheet such as paper to record images / characters. However, high speed, low noise, and multiple colors are achieved. It has features such as easy recording pattern flexibility, no need for development and fixing, and is rapidly spreading in various applications as a recording apparatus for various figures and color images including Chinese characters. Furthermore, images formed by the multi-color ink jet method can obtain recordings that are inferior to those of multi-color printing by the plate making method and printing by the color photographic method. Since it is cheaper than photographic technology, it has been widely applied to the field of full-color image recording.

  Recently, inkjet printers and the like that can output high-definition images comparable to images of silver salt photographs are commercially available at low cost. Inkjet recording sheets are very cheap compared to the silver halide photography method, but they are very cheap, so it is economical for users who frequently change their display images for advertisements or product samples that require large-area images. There are significant advantages. Also, it has been impossible to create an image on a personal computer, which has become popular recently, and correct the color scheme and layout while looking at the printout. There is also an advantage that such an operation can be easily performed. Against this background, there is an increasing demand for ink jet recording materials.

  For these ink jet recording materials, for the purpose of obtaining good ink jet recording performance, an ink jet recording material containing inorganic ultrafine particles has been proposed, and synthetic silica mainly having a primary particle diameter of 3 nm to 30 nm is used by a gas phase method. An inkjet recording medium is disclosed (for example, see Patent Documents 1 and 2).

  In addition, for the purpose of obtaining particularly good ink fixability and surface gloss, ink jet recording materials containing cationic inorganic oxide particles as inorganic ultrafine particles have been proposed (see, for example, Patent Documents 3 to 5). ).

  When the ink receiving layer containing such inorganic ultrafine particles is formed by a method of applying and drying the ink receiving layer coating liquid, the coating layer has a characteristic of being extremely shrunk when dried. Cracks are likely to occur, resulting in a decrease in surface gloss, deterioration in appearance, and ink absorption spots. Such cracks tend to occur more frequently as the coating layer is thicker and the drying speed is faster. In order to obtain a sufficient ink absorption capacity with an ink receiving layer containing inorganic ultrafine particles as a main component, the ink receiving layer needs to have a certain thickness or more, and the ink receiving layer is coated and dried to such a thickness. In particular, there is a problem that cracks tend to occur.

  As a method for preventing cracks due to drying shrinkage, there is a method using gelatin as a binder. Gelatin aqueous solution is generally in an aqueous solution state at about 30 ° C. or higher, but has a property of gelling at 20 to 25 ° C. or lower. Utilizing this property, after applying a water-based coating liquid containing gelatin on a support, cooling and gelling, and blowing by drying at a relatively low temperature (about 20 to 60 ° C.), A coating layer having a high film thickness can be obtained without generating cracks. However, it takes time to cool and gel, and it is necessary to dry at a relatively low temperature. Therefore, there is a problem that the drying time is long and the production efficiency is low. Further, when gelatin is used as the main binder of the ink receiving layer, there is a problem that ink is not sufficiently absorbed during ink jet recording, and the characteristics of the ink absorbing layer are not utilized.

  Instead of using gelatin, a method is known in which polyvinyl alcohol and boric acid or a salt thereof are contained in the coating liquid, and after the coating, cooling and gelation are carried out similarly to the case of using gelatin. According to this method, a coating layer having a high film thickness can be obtained without causing cracks, and higher ink absorbability can be obtained. However, even in this method, the production efficiency is low, and further improvement is desired.

In addition, for the purpose of obtaining high ink absorbability, a method of applying an ink-receiving layer coating solution that gels by heating and drying by heating has been proposed. It is difficult to go up, and heating for a long time is necessary to sufficiently gel the coating solution. For this reason, production efficiency is still insufficient.
JP-A-10-203006 (page 3-9) JP-A-8-174992 (page 3-6) JP-A-5-50739 (page 2-4) JP-A-6-55829 (page 2-3) JP-A-8-207431 (page 2-5)

  An object of the present invention is to form an ink receiving layer in which an ink receiving layer containing inorganic ultrafine particles as a main component is provided on a support, with no cracks in the coating layer and good print quality. It is a method, and an object thereof is to efficiently obtain an ink jet recording material using the forming method.

  As a result of earnest research to achieve the above object, there is provided a method for forming an ink receiving layer in which an ink receiving layer coating liquid containing inorganic ultrafine particles as a main component is applied to a support and dried. The coating liquid is gelled by heating, and after applying the ink-receiving layer coating liquid, a process of heating and gelation in an atmosphere having a relative humidity of 70% or more, and subsequent to the process, a relative humidity of less than 70% The method of forming an ink receiving layer is characterized by having a process of drying in an atmosphere of

  More preferably, the gelation of the ink-receiving layer coating liquid by heating is irreversible.

  More preferably, the ink receiving layer coating solution contains a water-soluble resin having a functional group selected from an amino group, an alkoxysilyl group, an acetoacetyl group, and a reactive ketone group, and a crosslinking agent capable of reacting with the functional group.

  It is more preferable to mix either the water-soluble resin or the substance that reacts or interacts with the water-soluble resin and gels into the coating solution immediately before coating.

  It is more preferable to control the time from mixing either the water-soluble resin or the substance that reacts or interacts with the water-soluble resin and gels into the coating liquid to apply it by the gelling speed of the coating liquid.

  When the application method is a pre-weighing method such as a curtain coater or slide bead coater, either the water-soluble resin or the substance that reacts or interacts with it and gels immediately before the coating solution enters the coater head. It is more preferable to perform in-line mixing and application.

  According to the present invention, a method for forming an ink receiving layer having good ink absorbability without causing cracks in the coating layer even when the ink receiving layer coating liquid is applied to a support and then rapidly dried by heating. Thus, an ink jet recording material using the forming method can be obtained efficiently.

  Below, the formation method of the ink receiving layer of this invention is demonstrated.

In the method for forming an ink receiving layer of the present invention, first, an ink receiving layer coating liquid containing inorganic ultrafine particles is applied to a support. The method for coating the coating liquid on the support is not particularly limited. Specific examples of the coating method include various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, curtain coaters, slide bead coaters, Short dwell coater, size press, etc. When the ink jet recording material is constituted by laminating a plurality of ink receiving layers, a multilayer coating liquid film composed of a plurality of coating liquid films is formed and applied, and two or more layers of ink are applied in one application. It is also possible to form a receiving layer. The coating amount of the ink receiving layer containing inorganic ultrafine particles is preferably 5 to 60 g / m ^{2 in} terms of solid coating amount. When the solid content coating amount exceeds 60 g / m ² , the coating layer is liable to crack.

  The temperature and viscosity of the coating liquid at the time of coating are not particularly limited, but 5 to 40 ° C. is preferable from the viewpoint of the fluidity of the coating liquid at the time of coating and the gelling property at the time of heating. The viscosity at the time of application can be adjusted to a value suitable for the application method, and is preferably 20 to 1000 mPa · sec.

  The applied coating liquid is gelled by heating before drying to prevent cracking of the coating layer, but is heated in an atmosphere with a relative humidity of 70% or more in order to increase its efficiency. Since the relative humidity of the heating atmosphere is high, evaporation of moisture from the coating layer is suppressed, and the temperature of the coating layer is efficiently increased. Therefore, in spite of the gelation by heating, the same effect as the gelation by cooling can be obtained.

  The temperature of the heating atmosphere is preferably 70 ° C. or higher. If the temperature is less than 70 ° C., the temperature of the coating layer is difficult to increase and sufficient production efficiency may not be obtained. After the ink receiving layer coating solution is applied, the coating layer is heated until the coating layer is gelled. The heating for performing the gelation is preferably 0.1 to 1 minute, and the productivity is 0.1 to 0.5 minute. This is more preferable.

  The ink receiving layer coating liquid is dried after the gelation by heating to form an ink receiving layer. Although the drying method is not particularly limited, a heat drying method such as a method of blowing hot air or a method of irradiating infrared rays is preferably used because of high productivity. The hot air temperature by the method of blowing hot air is preferably 70 ° C. or higher from the viewpoint of productivity. The drying time is preferably 0.1 to 1 minute, and more preferably 0.1 to 0.5 minute in terms of productivity.

  The inorganic ultrafine particles in the ink jet recording material of the present invention refer to inorganic fine particles having a primary particle diameter of 100 nm or less and a secondary particle diameter of 500 nm or less, for example, JP-A-1-97678 and JP-A-2-275510. Pseudoboehmite disclosed in JP-A-3-281383, JP-A-3-285814, JP-A-3-285815, JP-A-4-92183, JP-A-4267180, and JP-A-4-275717. Alumina hydrates such as sol, vapor phase alumina described in JP-A-8-72387, JP-A-60-219083, JP-A-69-1389, JP-A-61-188183, JP-A-63 Colloidal silica as described in JP-A-178074, JP-A-5-51470, and the like; And silica / alumina hybrid sols as described in JP-A-62-2286787, gas phase methods as described in JP-A-10-119423 and JP-A-10-217601 Silica sol in which silica is dispersed, silica sol obtained by pulverizing wet silica such as precipitated silica or gel method silica, and other smectite clays such as hectite and montmorillonite (JP-A-7-81210), zirconia sol, chromia sol, yttria Typical examples include sol, ceria sol, iron oxide sol, zircon sol, aluminum oxide sol, and antimony oxide sol.

  Among the above-mentioned inorganic ultrafine particles, alumina hydrate is particularly preferable. When alumina hydrate is used, cracks are less likely to occur on the surface of the coating layer, and higher surface gloss and higher printing density can be obtained.

The alumina hydrate used in the present invention can be represented by the following general formula. Al ₂ O ₃ · nH ₂ O alumina hydrates are classified into gypsite, vialite, norstrandite, boehmite, boehmite gel (pseudoboehmite), diaspore, amorphous amorphous, etc., depending on the composition and crystal form. The In particular, in the above formula, when the value of n is 1, it represents an alumina hydrate having a boehmite structure, and when n is more than 1 and less than 3, it represents an alumina hydrate having a pseudo boehmite structure, where n is 3 or more represents an amorphous alumina hydrate. In particular, the preferred alumina hydrate for the present invention is an alumina hydrate having a pseudo boehmite structure in which at least n is more than 1 and less than 3.

  The shape of the alumina hydrate used in the present invention may be any of a flat plate shape, a fiber shape, a needle shape, a spherical shape, a rod shape, and the like, and a preferable shape is a flat shape from the viewpoint of ink absorbability. The plate-like alumina hydrate has an average aspect ratio of 3 to 8, and preferably an average aspect ratio of 3 to 6. The aspect ratio is expressed as the ratio of the “diameter” to the “thickness” of the particles. Here, the diameter of the particle represents the diameter of a circle equal to the projected area of the particle when the alumina hydrate is observed with an electron microscope.

  The alumina hydrate used in the present invention can be produced by a known method such as hydrolysis of aluminum alkoxide such as aluminum isopropoxide, neutralization of aluminum salt with alkali, hydrolysis of aluminate. The physical properties of alumina hydrate, such as particle size, pore size, pore volume, and specific surface area, should be controlled by conditions such as precipitation temperature, aging temperature, aging time, solution pH, solution concentration, and coexisting compounds. Can do.

  As a method for obtaining alumina hydrate from alkoxide, JP-A-57-88074, JP-A-62-56321, JP-A-4-275717, JP-A-6-64918, JP-A-7-10535, JP-A-7-267633, U.S. Pat. No. 2,656,321 and the like disclose methods for hydrolyzing aluminum alkoxide. These aluminum alkoxides include isopropoxide, 2-butoxide and the like.

  The alumina hydrate used in the present invention is preferably an alumina hydrate having an average primary particle size of 3 nm to 25 nm. A particularly preferable average primary particle diameter is 5 nm to 20 nm. Further, the secondary particle diameter in which these are aggregated is preferably 50 nm to 200 nm.

  The content of the inorganic ultrafine particles in the ink receiving layer containing the inorganic ultrafine particles according to the present invention is 60% by mass or more based on the total solid content of the ink receiving layer, and 70 masses in terms of ink absorbability. % Or more is particularly preferable.

  Next, a method for imparting the property of gelation by heating to the ink receiving layer coating liquid containing inorganic ultrafine particles will be described.

  In order to give the ink-receiving layer coating liquid containing inorganic ultrafine particles the property of gelation by heating, a method in which the aqueous solution contains a water-soluble resin having the property of gelation by heating, the water-soluble resin and the reaction therewith Or the method of containing the substance which gelatinizes by interacting is mentioned.

  Specific examples of the water-soluble resin having the property that the aqueous solution is gelled by heating include a methylcellulose compound and an alkyl (meth) acrylamide copolymer. A methylcellulose compound is a compound in which a part of hydrogen atoms of a hydroxyl group in a cellulose molecule is substituted with a methyl group to form a methoxyl group, and cellulose is used as a raw material, treated with caustic soda, and then reacted with methyl chloride. Manufactured by the method. Further, a part of the hydrogen atoms of the hydroxyl group in the cellulose molecule is substituted with a methyl group, and may be further substituted with a substituent other than a methyl group such as a hydroxypropyl group or a hydroxyethyl group. In the ink jet recording material of the present invention, a material in which a part of the hydrogen atoms of the hydroxyl group in the cellulose molecule is substituted only with a methyl group is preferable because the gelation temperature is low.

  The alkyl (meth) acrylamide copolymer of the present invention essentially comprises an alkyl (meth) acrylamide monomer, and can be obtained by copolymerizing other monomers if necessary depending on the purpose. As specific examples of the alkyl (meth) acrylamide monomer, N-alkylacrylamide is preferable. Specific examples include N, N-diethylacrylamide, N-isopropylacrylamide, N-ethylacrylamide, N-cyclopropylacrylamide, and N-ethyl. Examples include methyl acrylamide, N-propyl ethyl acrylamide, N-propyl acrylamide, N-isopropyl methyl acrylamide, N-cyclopropyl methyl acrylamide, N-methyl-N-ethyl acrylamide, N-methyl-N-isopropyl acrylamide, etc. N-isopropylacrylamide is preferable, but it is not particularly limited.

  Next, a substance that gels by reacting or interacting with the water-soluble resin and the water-soluble resin will be described. As the water-soluble resin, a water-soluble resin having a reactive functional group is preferably used. Specific examples of reactive functional groups include amino groups, alkoxysilyl groups, acetoacetyl groups, reactive ketone groups, and epoxy groups.

  The water-soluble resin having an amino group is obtained by (co) polymerization of a monomer having an amino group. Examples of such monomers include ethyleneimine, vinylamine, allylamine and the like. Alternatively, an amino group may be added by a resin reaction.

  The water-soluble resin having an alkoxysilyl group is obtained by a method of (co) polymerizing a monomer having an alkoxysilyl group. Specific examples of the alkoxysilyl group include triethoxysilyl group, tributoxysilyl group, triisopropoxysilyl group, trimethoxysilyl group, methyltrimethoxysilyl group, methyltriethoxysilyl group, dimethyldimethoxysilyl group, dimethyldiethoxy group. A silyl group etc. are mentioned.

  The water-soluble resin having an acetoacetyl group is obtained by (co) polymerization of a monomer monomer having an acetoacetyl group. Examples of such a monomer include acetoacetoxyethyl (meth) acrylate. Alternatively, an acetoacetyl group may be added by a resin reaction.

  The water-soluble resin having a reactive ketone group is obtained by a method of (co) polymerizing a monomer having a reactive ketone group. An example of such a monomer is diacetone (meth) acrylamide. Alternatively, a reactive ketone group may be added by a resin reaction.

  The water-soluble resin having an epoxy group can be obtained by a method of (co) polymerizing a monomer having an epoxy group. Examples of such a monomer include glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and methacryl glycidyl ether. Alternatively, an epoxy group may be added by a resin reaction.

  In the present invention, among the water-soluble resins having the reactive functional group, modified PVA having the functional group is preferably used. Specific examples of the modified PVA include amino group-modified PVA, alkoxysilyl group-modified PVA, acetoacetyl group-modified PVA, diacetone amide-modified PVA, and epoxy-modified PVA. Among the modified PVA, polyvinyl alcohol having a saponification degree of 80% or more is more preferable, and polyvinyl alcohol having a saponification degree of 88% or more and less than 99% is more preferable. The average degree of polymerization is preferably 1000 or more, particularly preferably 2000 or more.

  Moreover, chitosan is preferably used as the water-soluble resin containing an amino group.

  The content of the water-soluble resin in the ink receiving layer containing the inorganic ultrafine particles is 100 parts by mass of the inorganic ultrafine particles in terms of gelation characteristics of the coating liquid, coating layer strength, coating layer cracking, and ink absorbability. It is 2-30 mass parts with respect to it, Preferably, it is 4-25 mass parts.

  The substance that reacts or interacts with the water-soluble resin and gels is one that reacts or interacts with the reactive functional group contained in the water-soluble resin.

  Examples of the substance that reacts or interacts with a water-soluble resin containing an amino group to form a gel include an epoxy compound and an aldehyde compound. Specific examples of the epoxy compound include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, adipic acid diglycidylate, o-phthalic acid diglycidylate, p-phthalic acid diglycidylate, and hydroquinone diester. Glycidyl ether, bisphenol diglycidyl ether, resorcin diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, neopentyl glycol diglycidyl ether, glycerol diglycidyl ether, glycerol Triglycidyl ether, sorbitol tetraglycidyl ether, pentaerythritol tet Glycidyl ether, diglycerol triglycidyl ether, triglycidyl - tris (2-hydroxyethyl) but isocyanurate, not be construed as being limited thereto.

  Specific examples of the aldehyde compound include, but are not limited to, formaldehyde, benzaldehyde, glyoxal, glutardialdehyde, glyoxal crosslinked starch, urethane prepolymer, and the like.

  Examples of the substance that reacts or interacts with a water-soluble resin containing an alkoxysilyl group and gels include silica fine particles having a dispersed particle size of 200 nm or less, such as colloidal silica and vapor phase method silica, and aldehyde compounds. Specific examples of the aldehyde compound are the same as those of the aldehyde compound.

  Examples of the substance that reacts or interacts with a water-soluble resin containing an acetoacetyl group and gels include polyvalent metal compounds, amine compounds, aldehyde compounds, hydrazine compounds, epoxy compounds, and methylol compounds.

  Specific examples of the polyvalent metal compound include calcium chloride, calcium sulfate, calcium acetate, calcium propionate, magnesium chloride, magnesium sulfate, zinc chloride, zinc sulfate, zinc acetate, aluminum chloride, aluminum sulfate, aluminum lactate, and titanium tetrachloride. , Titanium lactate, tetraisopropyl titanate, zirconium acetate, zirconium oxychloride, ammonium zirconium carbonate, chromium alum, potassium alum, basic polyaluminum hydroxide, cobalt chloride, ferrous chloride, ferrous sulfate, ferric chloride, Although chromium acetate, barium acetate, etc. are mentioned, it is not a thing limited to these.

Of the polyvalent metal compounds, zirconium compounds are particularly preferably used. Besides the above zirconium compounds, ZrO (OH) Cl, ZrOCl ₂ .nH ₂ O, Zr ₂ O ₃ Cl ₂ , ZrCl ₄ , ZrCl ₃ , ZrCl ₂ , ZrBr ₄ , ZrBr ₃ , ZrBr ₂ , ZrI ₄ , ZrI ₃ , ZrI ₂ , ZrF ₄ , ZrF ₃ , ZrF _{2 and} other halide salts, Zr (NO ₃ ) ₄ .nH ₂ O, ZrO (NO ₃ ) ₂ · nH ₂ O, Zr (SO ₄ ) ₂ , Zr (SO ₄ ) ₂ · nH ₂ O, ZrO (SO ₄ ), Zr (H ₂ PO ₄ ) ₂ , ZrP ₂ O ₇ , ZrSiO ₄ , ZrO (CO _{3) 2 · nH 2 O,} ZrO (OH) 2 · nH 2 O oxo acid salts such as lactate, zirconyl stearate, zirconyl octylate, zirconyl lauric acid, such as Manden acid zirconyl Machine acid salts, and the like.

  Specific examples of amine compounds include ethylenediamine, propylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, 1,3-bisaminomethylcyclohexane. , Phenylenediamine, diethylenetriamine, triethylenetetramine, triaminopropane, polymers having an amino group (for example, polyvinylamine, polyethyleneimine, polyallylamine) and the like, but are not limited thereto.

  Specific examples of the aldehyde compound are the same as those of the aldehyde compound.

  Specific examples of the hydrazine compound include carbohydrazide, thiocarbohydrazide, ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene-1,4-dihydrazine, oxalic acid dihydrazide, propionic acid dihydrazide, Malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide, maleic acid dihydrazide, fumaric acid dihydrazide, itaconic acid dihydrazide, salicylic acid dihydrazide, isophthalic acid dihydrazide benzene, 4'-dihydroxide Examples thereof include vinyl polymers having groups (for example, aminopolyacrylamide), but are not limited thereto.

  Specific examples of the epoxy compound are the same as the above examples.

  Specific examples of the methylol compound include N-methylol urea, methylol dimethylhydantoin, methylol melamine and the like. Specific examples of the aziridine compound include trimethylolpropane-tri-β-azyldinylpropionate, tetramethylolmethane-tri-β-aziridinylpropionate, N, N′-diphenylmethane-4,4′-bis. (1-aziridinecarboxamide), N, N′-hexamethylene-1,6′-bis (1-aziridinecarboxamide), N, N′-toluene-2,4′-bis (1-aziridinecarboxamide) ) And the like, but are not limited thereto.

  Examples of the substance that reacts with or interacts with a water-soluble resin containing a reactive ketone group to form a gel include amine compounds and hydrazine compounds. Specific examples of the amine compound and the hydrazine compound are the same as those described above.

  Examples of the substance that reacts or interacts with a water-soluble resin containing an epoxy group to form a gel include an amine compound. Specific examples of the amine compound are the same as those described above.

  The use ratio of the water-soluble resin containing a reactive functional group and the substance that gels by reacting or interacting with the water-soluble resin is preferably 0.2% by mass or more and 10% by mass or less with respect to the water-soluble resin. When the ratio is less than 0.2% by mass, the gelation of heating becomes insufficient, and cracks may occur in the coating layer. On the other hand, if the ratio exceeds 10% by mass, gelation may occur vigorously and application may become difficult.

  The water-soluble resin and the substance that gels by reacting with or interacting with the water-soluble resin can be used in combination of two or more, as long as there is no adverse effect on the function.

  Since the gelation by the above-described method of containing a water-soluble resin having a property of gelling by heating is reversible, the gelation may be eliminated when the temperature of the coating liquid is lowered in the drying step after gelation. is there. Therefore, drying after gelation is preferably performed at a high temperature. On the other hand, in the method of containing a water-soluble resin and a substance that reacts with or interacts with the water-soluble resin, gelation proceeds gradually even at low temperatures, but the gelation is remarkably accelerated by heating. Moreover, since this gelation is irreversible, gelation is not eliminated even in the drying step after gelation, and is particularly preferable because it can be dried in a very strong gel state.

  In the method of adding a water-soluble resin and a substance that gels by reacting or interacting with the water-soluble resin, after the water-soluble resin and a substance that reacts or interacts with the water-soluble resin are mixed, the gelation gradually proceeds even at low temperatures. proceed. Mixing either a water-soluble resin or a substance that reacts or interacts with it and gels into the coating liquid immediately before coating improves the fluidity of the coating liquid at the time of coating, improves the coating properties, and heats it. It is preferable that gelation is sufficiently performed. The time from mixing either the water-soluble resin or the substance that reacts or interacts with it or gels into the coating solution to the coating can be adjusted as appropriate in consideration of the gelation rate of the coating solution. it can.

  When the application method is a pre-weighing method such as a curtain coater or slide bead coater, either the water-soluble resin or the substance that reacts or interacts with this and gels, and the coating solution is applied to the coater head. It is particularly preferred that stable coating can be performed by in-line mixing immediately before entering.

  Various thickeners such as polyvinyl alcohol other than the above water-soluble resins, water-soluble polymers such as starch, and acrylic emulsions are applied to the coating liquid applied by the method for producing an inkjet recording material of the present invention. Can be added to the coating liquid to increase the viscosity, the solid content concentration of the coating liquid can be increased to increase the viscosity, or conversely, the coating liquid can be diluted to decrease the viscosity.

  In order to adjust the surface tension of the coating liquid, anionic surfactants such as carboxylate, sulfonate, sulfate ester, phosphate ester, ether type, ether ester type, ester type, nitrogen-containing type, etc. Any amount of an amphoteric surfactant such as a nonionic surfactant, betaine, aminocarboxylate, or imidazoline derivative can be mixed in the coating solution.

  In the coating liquid applied by the method for producing an inkjet recording material of the present invention, a dye fixing agent, a pigment dispersant, a thickener, a fluidity improver, an antifoaming agent, an antifoaming agent, and a release agent are added as additives. Foaming agent, penetrating agent, coloring dye, coloring pigment, fluorescent whitening agent, UV absorber, antioxidant, preservative, antibacterial agent, water resistance agent, wet paper strength enhancer, dry paper strength enhancer, etc. It can mix | blend suitably.

  In particular, secondary amines, tertiary amines that form insoluble salts with sulfonic acid groups, carboxyl groups, amino groups, etc. in water-soluble direct dyes and water-soluble acidic dyes that are dye components of water-based inks used in inkjet printers, When a cationic dye fixing agent composed of a quaternary ammonium salt is added, the dye is trapped in the ink receiving layer, so that the ink flows out and bleeds by dripping water or absorbing moisture due to the improvement of color and the formation of insoluble salts. This is preferable because it suppresses the ejection.

  The support used for the ink jet recording material produced by the method for producing an ink jet recording material of the present invention may be transparent, translucent or opaque, and is made of paper, various non-woven fabrics, woven fabrics, synthetic resin films, synthetic resin laminates. Paper, synthetic paper, metal foil, ceramic paper, glass plate, or a composite sheet combining these can be arbitrarily used according to the purpose, but is not limited thereto.

  As the paper used as the support, chemical pulp such as LBKP and NBKP, wood pulp such as GP, PGW, RMP, mechanical pulp such as TMP, CTMP, CMP, and CGP, waste paper pulp such as DIP, and conventionally known pigments are mainly used. As a component, a binder, a sizing agent, a fixing agent, a yield improver, a cationizing agent, a paper strength enhancer and the like are mixed using one or more additives, and a long net paper machine, a circular net paper machine, a twin wire paper machine. Base paper manufactured by various devices such as a machine, base paper provided with size press or anchor coat layer with starch, polyvinyl alcohol, etc., or art paper, coated paper, cast with a coat layer on them Coated paper such as coated paper is also included. Such base paper and coated paper may be provided with the coating layer in the present invention as they are, or a calendar device such as a machine calendar, a TG calendar, and a soft calendar may be used for the purpose of controlling flattening.

  EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples. In the examples, “parts” and “%” indicate parts by mass and mass% unless otherwise specified.

Preparation of “Alumina Hydrate Dispersion” 1200 parts of ion exchange water and 900 parts of isopropyl alcohol were charged in a reactor and heated to 75 ° C. 408 parts of aluminum isopropoxide was added, and hydrolysis was performed at 75 ° C. for 24 hours and at 95 ° C. for 4 hours. Thereafter, 24 parts of acetic acid was added, and the mixture was stirred at 95 ° C. for 40 hours, concentrated to a solid content of 20%, adjusted to pH 4.0 by adding acetic acid, and dispersed in alumina hydrate. A liquid was obtained.

  When this sol was dried at room temperature and measured for X-ray diffraction, it showed a pseudo-boehmite structure. Further, when the average particle diameter was measured with a transmission electron microscope, it was about 20 nm and was an alumina hydrate having a flat pseudoboehmite structure with an aspect ratio of 5.

Preparation of “gas phase method silica dispersion” In 396 parts of ion-exchanged water, 4 parts of 50% dimethyldiallylammonium chloride homopolymer (molecular weight 9000), gas phase method silica (average primary particle size 12 nm, specific surface area 200 m ² by BET method) / G) 100 parts were added, and a preliminary dispersion was prepared using a sawtooth blade type disperser. The obtained preliminary dispersion was treated with a high-pressure homogenizer to obtain a 20% gas phase silica dispersion.

Preparation of “acrylamide copolymer” 50 g of N-isopropylacrylamide and 50 g of trimethylammoniumpropylacrylamide chloride were introduced as monomers into a 1-liter four-necked flask equipped with a thermometer, stirrer, nitrogen inlet tube and reflux condenser. Then, 400 g of distilled water and 100 g of ethanol were added and dissolved as a solvent, and the mixture was stirred in a nitrogen atmosphere on a 50 ° C. water bath. Polymerization is started by adding 0.9 g of V-50 (manufactured by Wako Pure Chemicals Co., Ltd., 2,2'-azobis (2-methylpropionamidine) dihydrochloride), followed by heating and stirring on a water bath for 4 hours. went. Distilled water was added so that the solid content of the obtained solution was 10%, and an “acrylamide copolymer” solution was obtained.

  26 parts of water was mixed with 72.4 parts of the above-mentioned alumina sol dispersion. While stirring this mixed solution, 1.45 parts of methylcellulose (water-soluble resin, Metrows SM-100 manufactured by Shin-Etsu Chemical Co., Ltd.) was slowly added and dissolved. To this was added 0.072 part of a polyoxyethylene alkylphenol type surfactant (NP-10, manufactured by Nikko Chemical Co., Ltd.) to prepare “Coating Liquid 1” having a solid content concentration of 16%.

Using “Coating fluid 1”, an extrusion hopper type curtain coating device was used to form a curtain film with a flow rate per curtain width of 7500 ml / min on a white polyethylene terephthalate film having a coating speed of 50 m / min and a thickness of 100 μm. It was applied to. Subsequently, after passing through a heating zone filled with air having a temperature of 120 ° C. and a relative humidity of 90% for 20 seconds and heating, a hot air drying zone having a temperature of 150 ° C. and a relative humidity of 3% is passed for 30 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ² , and the ink jet recording material of Example 1 was produced.

  72.4 parts of the above-mentioned alumina sol dispersion, 14.5 parts of the above-mentioned acrylamide copolymer solution, 13 parts of water, 0.072 part of polyoxyethylene alkylphenol type surfactant (NP-10 manufactured by Nikko Chemical Co., Ltd.) Mixing and stirring were performed to prepare “Coating liquid 2” having a solid content concentration of 16%.

Using “Coating fluid 2”, an extrusion hopper type curtain coating device forms a curtain film with a flow rate per curtain width of 7500 ml / min, on a white polyethylene terephthalate film with a coating speed of 50 m / min and a thickness of 100 μm. It was applied to. Subsequently, after heating through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90% over 20 seconds, the coating liquid is dried by passing through a hot air drying zone at 150 ° C. for 30 seconds to obtain a solid. An ink receiving layer having a coating amount of 24 g / m ² was formed, and the ink jet recording material of Example 2 was produced.

  72.1 parts of the above-mentioned alumina sol dispersion, 14.4 parts of 10% chitosan aqueous solution, 12 parts of water, 0.072 part of polyoxyethylene alkylphenol type surfactant (NP-10 manufactured by Nikko Chemical Co., Ltd.) are mixed and stirred. Then, “Coating liquid 3” having a solid content concentration of 16.2% was prepared.

“Coating liquid 3” and 5% aqueous solution of glyoxal were fed while being mixed in-line so that the mass ratio was 68.4: 1, and the flow rate per 1 m of curtain width was 7500 ml / min with an extrusion hopper type curtain coating device. The curtain film was formed and coated on a white polyethylene terephthalate film having a thickness of 100 μm at a coating speed of 50 m / min. Subsequently, after passing through a heating zone filled with air having a temperature of 120 ° C. and a relative humidity of 90% for 20 seconds and heating, a hot air drying zone having a temperature of 150 ° C. and a relative humidity of 3% is passed for 30 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ^{2, and} an ink jet recording material of Example 3 was produced.

  Gas phase method silica dispersion 41.1 parts, 10% chitosan aqueous solution 16.4 parts, water 40.4 parts, polyoxyethylene alkylphenol type surfactant (NP-10 manufactured by Nikko Chemical Co., Ltd.) 0.041 Parts were mixed and stirred to prepare “Coating Liquid 4” with a solid content concentration of 10.1%.

“Coating solution 4” and 5% aqueous glyoxal solution were fed while being mixed in-line at a mass ratio of 47.7: 1, and the flow rate per 1 m of curtain width was 7500 ml / min with an extrusion hopper type curtain coating device. The curtain film was formed on a white polyethylene terephthalate film having a thickness of 100 μm at a coating speed of 31.2 m / min. Subsequently, after passing through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90% for 32 seconds and heating, it is passed through a hot air drying zone at 150 ° C. and a relative humidity of 3% for 48 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ^{2, and} an ink jet recording material of Example 4 was produced.

  71.8 parts of the above-mentioned alumina sol dispersion liquid, 10% acetoacetyl group-modified PVA aqueous solution (water-soluble resin having a reactive functional group, GOHSEIMER Z-200 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), water 10.9 parts, 0.072 part of polyoxyethylene alkylphenol type surfactant (NP-10, manufactured by Nikko Chemical Co., Ltd.) was mixed and stirred to prepare “Coating Liquid 5” with a solid content concentration of 16.3%. .

“Coating solution 5” and 5% adipic acid dihydrazide aqueous solution were fed while being mixed in-line so that the mass ratio was 33.8: 1, and the flow rate per 1 m of curtain width was 7500 ml by an extrusion hopper type curtain coating device. A curtain film was formed on a white polyethylene terephthalate film having a thickness of 100 μm at a coating speed of 50 m / min. Subsequently, after passing through a heating zone filled with air having a temperature of 120 ° C. and a relative humidity of 90% for 20 seconds and heating, a hot air drying zone having a temperature of 150 ° C. and a relative humidity of 3% is passed for 30 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ^{2, and} an ink jet recording material of Example 5 was produced.

  39.5 parts of the above-mentioned gas phase method silica dispersion, 10% acetoacetyl group-modified PVA aqueous solution (water-soluble resin having a reactive functional group, Gosei Famer Z-200 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 19.8 Part, 39.1 parts of water, 0.04 part of polyoxyethylene alkylphenol type surfactant (NP-10 manufactured by Nikko Chemical Co., Ltd.) is mixed and stirred, and “coating liquid 6” having a solid content concentration of 10.1% Was prepared.

“Coating liquid 6” and 5% adipic acid dihydrazide aqueous solution were fed while being mixed in-line so that the mass ratio was 62.3: 1, and the flow rate per 1 m of curtain width was 7500 ml by an extrusion hopper type curtain coating apparatus. A curtain film was formed on a white polyethylene terephthalate film having a thickness of 100 μm at a coating speed of 31.2 m / min. Subsequently, after passing through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90% for 32 seconds and heating, it is passed through a hot air drying zone at 150 ° C. and a relative humidity of 3% for 48 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ^{2, and} an ink jet recording material of Example 6 was produced.

  71.8 parts of the above-mentioned alumina sol dispersion, 10.4 parts of 10% diacetone acrylamide group-modified PVA aqueous solution (water-soluble resin having reactive functional groups, DF-17, manufactured by Nippon Acetate / Poval Co., Ltd.), water 11 Part, 0.072 part of polyoxyethylene alkylphenol type surfactant (NP-10, manufactured by Nikko Chemical Co., Ltd.) was mixed and stirred to prepare “Coating Liquid 7” having a solid content concentration of 16.3%.

“Coating liquid 7” and 5% adipic acid dihydrazide aqueous solution were fed while being mixed in-line so that the mass ratio was 33.8: 1, and the flow rate per 1 m of curtain width was 7500 ml by an extrusion hopper type curtain coating apparatus. A curtain film was formed on a white polyethylene terephthalate film having a thickness of 100 μm at a coating speed of 50 m / min. Subsequently, after passing through a heating zone filled with air having a temperature of 120 ° C. and a relative humidity of 90% for 20 seconds and heating, a hot air drying zone having a temperature of 150 ° C. and a relative humidity of 3% is passed for 30 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ^{2, and} an ink jet recording material of Example 7 was produced.

  39.5 parts of the above-mentioned gas phase method silica dispersion, 10% diacetone acrylamide group-modified PVA aqueous solution (water-soluble resin having a reactive functional group, DF-17 manufactured by Nihon Acetate / Poval Co., Ltd.) 19.8 parts , 39.1 parts of water, 0.04 part of polyoxyethylene alkylphenol type surfactant (NP-10, manufactured by Nikko Chemical Co., Ltd.) were mixed and stirred, and "Coating Liquid 8" with a solid content concentration of 10.1% was mixed. Prepared.

“Coating liquid 8” and 5% adipic acid dihydrazide aqueous solution were fed while being mixed in-line so that the mass ratio was 62.3: 1, and the flow rate per 1 m of curtain width was 7500 ml by an extrusion hopper type curtain coating apparatus. A curtain film was formed on a white polyethylene terephthalate film having a thickness of 100 μm at a coating speed of 31.2 m / min. Subsequently, after passing through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90% for 32 seconds and heating, it is passed through a hot air drying zone at 150 ° C. and a relative humidity of 3% for 48 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ^{2, and} an ink jet recording material of Example 8 was produced.

  71.1 parts of the above-mentioned alumina sol dispersion, 10.2 parts of 10% silyl group-modified PVA aqueous solution (water-soluble resin having reactive functional groups, R-1130 manufactured by Kuraray Co., Ltd.), 13.9 parts of water, polyoxy 0.071 part of an ethylene alkylphenol type surfactant (NP-10 manufactured by Nikko Chemical Co., Ltd.) was mixed and stirred to prepare “Coating Liquid 9” having a solid content concentration of 15.8%.

“Coating solution 9” and 40% aqueous glyoxal solution were fed while being mixed in-line so that the mass ratio was 139.6: 1, and the flow rate per 1 m of curtain width was 7500 ml / min with an extrusion hopper type curtain coating device. The curtain film was formed and coated on a white polyethylene terephthalate film having a thickness of 100 μm at a coating speed of 50 m / min. Subsequently, after passing through a heating zone filled with air having a temperature of 120 ° C. and a relative humidity of 90% for 20 seconds and heating, a hot air drying zone having a temperature of 150 ° C. and a relative humidity of 3% is passed for 30 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ^{2, and} an ink jet recording material of Example 9 was produced.

  71.7 parts of the above-mentioned alumina sol dispersion, 10% epoxy group-modified PVA aqueous solution (water-soluble resin having a reactive functional group, Denka Size W-100 manufactured by Denki Kagaku Kogyo Co., Ltd.), 11 parts of water, 0.072 part of polyoxyethylene alkylphenol type surfactant (NP-10 manufactured by Nikko Chemical Co., Ltd.) was mixed and stirred to prepare “Coating Liquid 10” having a solid content concentration of 16.3%.

“Coating solution 10” and 5% ethylenediamine aqueous solution were fed while being mixed in-line so that the mass ratio was 33.8: 1, and the flow rate per 1 m of curtain width was 7500 ml / min with an extrusion hopper type curtain coating device. The curtain film was formed and coated on a white polyethylene terephthalate film having a thickness of 100 μm at a coating speed of 50 m / min. Subsequently, after passing through a heating zone filled with air having a temperature of 120 ° C. and a relative humidity of 90% for 20 seconds and heating, a hot air drying zone having a temperature of 150 ° C. and a relative humidity of 3% is passed for 30 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ^{2, and} an ink jet recording material of Example 10 was produced.

  39.5 parts of the above gas phase method silica dispersion, 10% epoxy group-modified PVA aqueous solution (water-soluble resin having a reactive functional group, Denka Size W-100 manufactured by Denki Kagaku Kogyo Co., Ltd.) 19.8 parts, water 39.1 parts, 0.04 part of polyoxyethylene alkylphenol type surfactant (NP-10, manufactured by Nikko Chemical Co., Ltd.) was mixed and stirred to prepare “Coating Liquid 11” with a solid content concentration of 10.1%. .

“Coating solution 11” and 5% ethylenediamine aqueous solution were fed while being mixed in-line so that the mass ratio was 62.3: 1, and the flow rate per 1 m of curtain width was 7500 ml / min by an extrusion hopper type curtain coating device. The curtain film was formed on a white polyethylene terephthalate film having a thickness of 100 μm at a coating speed of 31.2 m / min. Subsequently, after passing through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90% for 32 seconds and heating, it is passed through a hot air drying zone at 150 ° C. and a relative humidity of 3% for 48 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ^{2, and} an ink jet recording material of Example 11 was produced.

(Comparative Example 1)
In Example 1, after application, the sample was directly passed through a hot air drying zone at 150 ° C. and 3% relative humidity over 30 seconds without passing through a heating zone filled with air at 120 ° C. and 90% relative humidity. An ink receiving layer was formed under the same conditions as in Example 1 except that the liquid was dried, and an inkjet recording material of Comparative Example 1 was produced.

(Comparative Example 2)
In Example 2, after application, the sample was directly passed through a hot air drying zone at 150 ° C. and 3% relative humidity over 30 seconds without passing through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90%. An ink receiving layer was formed under the same conditions as in Example 2 except that the liquid was dried, and an inkjet recording material of Comparative Example 2 was produced.

(Comparative Example 3)
In Example 3, after passing through the heating zone filled with air having a temperature of 120 ° C. and a relative humidity of 90%, it was directly passed through a hot air drying zone having a temperature of 150 ° C. and a relative humidity of 3% over 30 seconds. An ink receiving layer was formed under the same conditions as in Example 3 except that the liquid was dried, and an inkjet recording material of Comparative Example 3 was produced.

(Comparative Example 4)
In Example 4, after application, the sample was directly passed through a hot air drying zone at 150 ° C. and 3% relative humidity over 48 seconds without passing through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90%. An ink receiving layer was formed under the same conditions as in Example 4 except that the liquid was dried, and an inkjet recording material of Comparative Example 4 was produced.

(Comparative Example 5)
In Example 5, after application, the sample was directly passed through a hot air drying zone at 150 ° C. and 3% relative humidity over 30 seconds without passing through a heating zone filled with air having a temperature of 120 ° C. and a relative humidity of 90%. An ink receiving layer was formed under the same conditions as in Example 5 except that the liquid was dried, and an inkjet recording material of Comparative Example 5 was produced.

(Comparative Example 6)
In Example 6, after application, the sample was directly passed through a hot air drying zone at 150 ° C. and 3% relative humidity over 48 seconds without passing through a heating zone filled with air at a temperature of 120 ° C. and 90% relative humidity. An ink receiving layer was formed under the same conditions as in Example 6 except that the liquid was dried, and an inkjet recording material of Comparative Example 6 was produced.

(Comparative Example 7)
In Example 7, after application, the sample was directly passed through a hot air drying zone at 150 ° C. and 3% relative humidity over 30 seconds without passing through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90%. An ink receiving layer was formed under the same conditions as in Example 7 except that the liquid was dried, and an inkjet recording material of Comparative Example 7 was produced.

(Comparative Example 8)
In Example 8, after application, the sample was directly passed through a hot air drying zone at 150 ° C. and 3% relative humidity over 48 seconds without passing through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90%. An ink receiving layer was formed under the same conditions as in Example 8 except that the liquid was dried, and an inkjet recording material of Comparative Example 8 was produced.

(Comparative Example 9)
In Example 9, after application, the sample was directly passed through a hot air drying zone at 150 ° C. and 3% relative humidity over 30 seconds without passing through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90%. An ink receiving layer was formed under the same conditions as in Example 9 except that the liquid was dried, and an inkjet recording material of Comparative Example 9 was produced.

(Comparative Example 10)
In Example 10, after application, the sample was directly passed through a hot air drying zone at 150 ° C. and 3% relative humidity over 30 seconds without passing through a heating zone filled with air having a temperature of 120 ° C. and a relative humidity of 90%. An ink receiving layer was formed under the same conditions as in Example 10 except that the liquid was dried, and an inkjet recording material of Comparative Example 10 was produced.

(Comparative Example 11)
In Example 11, after application, the sample was directly passed through a hot air drying zone at 150 ° C. and 3% relative humidity over 48 seconds without passing through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90%. An ink receiving layer was formed under the same conditions as in Example 11 except that the liquid was dried, and an inkjet recording material of Comparative Example 11 was produced.

(Comparative Example 12)
72.4 parts of the above-mentioned alumina sol dispersion, 18.1 part of 8% polyvinyl alcohol aqueous solution (water-soluble resin, PVA-235 manufactured by Kuraray Co., Ltd.), 9.4 parts of water, polyoxyethylene alkylphenol type surfactant (Nikko) Chemical Co., Ltd. NP-10) 0.072 part was mixed and stirred, and "the coating liquid 12" with a solid content concentration of 16% was prepared.

Using “Coating fluid 12”, an extrusion hopper type curtain coating device was used to form a curtain film with a flow rate of 7500 ml / min per 1 m of curtain width, on a white polyethylene terephthalate film with a coating speed of 50 m / min and a thickness of 100 μm. It was applied to. Subsequently, after passing through a heating zone filled with air having a temperature of 120 ° C. and a relative humidity of 90% for 20 seconds and heating, a hot air drying zone having a temperature of 150 ° C. and a relative humidity of 3% is passed for 30 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ^{2, and} an ink jet recording material of Comparative Example 12 was produced.

(Comparative Example 13)
72.4 parts of the above-mentioned alumina sol dispersion, 14.5 parts of 10% acetoacetyl group-modified PVA aqueous solution (water-soluble resin having a reactive functional group, Gosei Famer Z-200 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), water 13 parts of polyoxyethylene alkylphenol type surfactant (NP-10 manufactured by Nikko Chemical Co., Ltd.) 0.072 part was mixed and stirred to prepare “Coating liquid 13” having a solid content of 16%.

Using “Coating fluid 13”, an extrusion hopper type curtain coating device was used to form a curtain film with a flow rate of 7500 ml / min per 1 m of curtain width, on a white polyethylene terephthalate film with a coating speed of 50 m / min and a thickness of 100 μm. It was applied to. Subsequently, after passing through a heating zone filled with air having a temperature of 120 ° C. and a relative humidity of 90% for 20 seconds and heating, a hot air drying zone having a temperature of 150 ° C. and a relative humidity of 3% is passed for 30 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ^{2, and} an ink jet recording material of Comparative Example 13 was produced.

(Comparative Example 14)
39.8 parts of the above gas phase method silica dispersion, 10% acetoacetyl group-modified PVA aqueous solution (water-soluble resin having a reactive functional group, Gosei Famer Z-200 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) 19.9 Part, water 40.1 parts, polyoxyethylene alkylphenol type surfactant (NP-10 manufactured by Nikko Chemical Co., Ltd.) 0.04 part is mixed and stirred to prepare “Coating liquid 14” with a solid content concentration of 10%. did.

A white polyethylene terephthalate film having a coating thickness of 31.2 m / min and a thickness of 100 μm is formed using the “coating liquid 14” by an extrusion hopper type curtain coating apparatus with a flow rate per curtain width of 7500 ml / min. It was applied on top. Subsequently, after passing through a heating zone filled with air at a temperature of 120 ° C. and a relative humidity of 90% for 32 seconds and heating, it is passed through a hot air drying zone at 150 ° C. and a relative humidity of 3% for 48 seconds. Was dried to form an ink receiving layer having a solid content coating amount of 24 g / m ² , and an inkjet recording material of Comparative Example 14 was produced.

Evaluation Images were printed on the ink jet recording materials produced in Examples 1 to 11 and Comparative Examples 1 to 14 using “PM-800C (printer setting: super fine paper, clean)” manufactured by Seiko Epson Corporation, and the coating layer The presence or absence of cracks and ink absorbability were evaluated. The image used for evaluation is composed of solid prints of black, cyan, magenta, yellow, blue, red, green, and a pattern in which white characters are provided.

  The presence or absence of cracks in the coating layer was expressed by numerical values of 1 to 5 by visually evaluating the surface of the produced inkjet recording material. The results are shown in “Crack of coating layer” in Table 1. “5” indicates the least cracks and “1” indicates the most cracks.

  For the surface gloss, the 20-degree specular gloss was measured by the method for measuring the specular gloss specified in JIS standard Z8741. The results are shown in “Surface Gloss” in Table 1.

  The print quality was evaluated by visually observing the uniformity of a solid print portion, the boundary between adjacent solid print portions, the sharpness of white characters, and the like, and was represented by a numerical value of 1 to 10. 1 indicates the worst printing quality, and the higher the numerical value, the better. 10 indicates the best. The results are shown in “Print quality” in Table 1.

  In Table 1, as shown in Examples 1 to 11, an ink-receiving layer coating solution that gels by heating is applied to a support, heated in an atmosphere with a relative humidity of 70% or more, and then dried. An ink receiving layer having no cracks in the layer and a good printed product could be formed, and an ink jet recording material could be obtained efficiently.

  In Comparative Examples 1 to 11, since the ink-receiving layer coating liquid that gels by heating was applied to the support and then dried without heating in an atmosphere with a relative humidity of 70% or more, the coating layer was cracked. The surface gloss and the print quality were inferior.

  In Comparative Examples 12 to 14, since the ink receiving layer coating liquid does not gel by heating, after applying the ink receiving layer coating liquid, heating in an atmosphere with a relative humidity of 70% or more forms an ink receiving layer. Even so, cracks occurred in the coating layer, and both surface gloss and print quality were inferior.

Claims (7)

  A method for forming an ink-receiving layer comprising applying and drying an ink-receiving layer coating liquid containing inorganic ultrafine particles as a main component on a support, wherein the ink-receiving layer coating liquid is gelled by heating, and After the ink-receiving layer coating liquid is applied, it has a process of heating and gelation in an atmosphere having a relative humidity of 70% or more, and a process of drying in an atmosphere having a relative humidity of less than 70% following the process. Method for forming ink receiving layer.   2. The method of forming an ink receiving layer according to claim 1, wherein gelation of the ink receiving layer coating liquid by heating is irreversible.   A water-soluble resin having a functional group selected from an amino group, an alkoxysilyl group, an acetoacetyl group, a reactive ketone group and an epoxy group, and a substance that gels by reacting or interacting with the water-soluble resin The method for forming an ink receiving layer according to claim 1 or 2, comprising:   4. The method of forming an ink receiving layer according to claim 3, wherein either the water-soluble resin or the substance that reacts or interacts with the water-soluble resin and gels is mixed with the coating liquid immediately before coating.   The time from mixing either the water-soluble resin or a substance that reacts or interacts with the water-soluble resin and gels into the coating liquid to apply is controlled by the gelation speed of the coating liquid. Item 5. The method for forming an ink receiving layer according to Item 3 or 4.   When the application method is a pre-weighing method selected from curtain coaters and slide bead coaters, either the water-soluble resin or the substance that reacts with or interacts with it and gels before it enters the coater head. The method for forming an ink receiving layer according to claim 3, wherein the coating is performed by in-line mixing.   An ink jet recording material using the method for forming an ink receiving layer according to claim 1.