JP2005288884A - Inkjet recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording material having iridescence with vivid beautiful color tone. <P>SOLUTION: In a pigment formed by covering a flake-like base with titania, zirconia or their mixture, by providing an ink accepting layer including a nacreous pigment, which is obtained by employing a hydrolyzable and polycondensable organic metal compound as a starting material, in the flake-like base, a nacreous paper suitably used for inkjet recording can be obtained. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an ink jet recording material containing a pearlescent pigment, particularly a pearlescent pigment having a flaky substrate coated with a metal oxide, in an ink receiving layer.

  Nacreous paper is a coated paper with a nacreous surface gloss coating layer (pearl luster layer), has a unique beautiful appearance, and is widely used as posters, packaging materials, various decorative materials, etc. Yes. The pearly luster layer is generally composed mainly of flat particles such as natural mica and titanium oxide coated mica, which are called pearl luster pigments and pearl pigments, and a binder resin (adhesive) for fixing them onto the substrate. It is said. For pearly glossy paper, many improved technologies for improving glossiness and printability have been proposed (see, for example, Patent Documents 1 to 3).

  On the other hand, pearlescent pigments in which a translucent layer of titania is formed on mica flakes are widely used as various pigments having pearly luster or cosmetic fillers such as cosmetic creams.

  As a method of coating titania on mica flakes, a method of hydrolyzing an acidic titanium oxysulfate solution at a boiling temperature and a method of hydrolyzing titanium tetrachloride are generally known.

  In these methods, after titania hydrate is coated, heat treatment is performed at 700 to 1000 ° C. to form a titania coating layer having a high stability and high brightness.

  As mica, muscovite mica is usually used. Such mica has a cleavage property, but the surface of the mica flake is not completely cleaved, the thickness is not uniform even within one mica flake, and the surface has stepped irregularities. This uneven step is usually larger than 0.05 μm and smaller than 1 μm.

  Conventional pearlescent paper is made for offset printing using oil-based ink, and is not suitable for an ink jet recording method using water-based ink. That is, conventional pearl gloss paper contains a large amount of binder resin, and is poor in absorbability of water-based inks such as water-based dye inks and water-based pigment inks that are general ink jet recording inks. When printing, ink is not absorbed and overflows on the surface, ink bleeding and printing unevenness occurs, perfect circular dots cannot be formed, image density is low, ink fixability is poor and background stains occur, due to poor drying A problem such as sticking occurred and a good image could not be obtained.

  In pearlescent paper using mica, the step on the surface of the mica flakes is a factor that inhibits the multiple reflection interference in the titania layer in the pigment after the titania layer is formed. There was a drawback that the color did not feel deep when viewed at a small size.

On the other hand, when a commercially available flaky glass is used instead of the mica flakes, there is no step on the surface, and the smoothness is excellent. However, since the glass composition is soda-lime silicate glass, there is a problem in heat resistance. That is, the glass flakes cannot withstand the step of heat treatment at 700 to 1000 ° C. after the titania layer is formed, and the heat treatment temperature must be suppressed to 600 ° C. or lower. In such a low-temperature heat treatment, the crystal structure of the titania layer is an anatase structure, so that it cannot be a pearlescent pigment having high luster and excellent durability, and therefore cannot be used for an ink jet recording material. It was.
Japanese Patent Publication No. 1-447597 JP-A-5-339897 JP 9-49192 A, etc. JP 2003-80836 A

  An object of the present invention is to provide a pearly luster paper for ink-jet recording which has a pearly luster with a bright and beautiful color tone, is excellent in color developability, and can provide a high-quality recorded matter without ink bleeding or printing unevenness. is there.

  As a result of intensive studies, the present inventors have used a pigment obtained by coating titania or zirconia or a mixture thereof on a flaky substrate, and using the organometallic compound that can be hydrolyzed and polycondensed as a starting material as the flaky substrate. It has been found that by including the obtained pearl luster pigment in the ink receiving layer, a pearl luster paper suitably used for ink jet recording can be obtained.

  That is, the present invention relates to a pearlescent pigment obtained by using, as a starting material, an organometallic compound that can be hydrolyzed and polycondensed as a flaky substrate in a pigment obtained by coating titania or zirconia or a mixture thereof on a flaky substrate. Is an ink jet recording material containing an ink receiving layer.

  2. The ink jet recording material according to claim 1, wherein the flaky substrate is a glass containing 80% by weight or more of silica.

  The organometallic compound is preferably a metal alkoxide having an alkoxyl group, and the metal alkoxide is further obtained when the methoxide, ethoxide, propoxide, butoxide of silicon, titanium, aluminum, zirconium, phosphorus, boron is a simple substance or a mixture. preferable. The solvent of the raw material solution containing the organometallic compound is preferably at least one alcohol selected from methanol, ethanol, propanol, and butanol. Furthermore, the volume ratio is 0.1 to 0.995 with respect to the total amount of the organometallic compound and the solvent, or the hydrolysis of the organometallic compound is selected from at least one of hydrochloric acid, nitric acid, and sulfuric acid. Whether it is acidic water, 1 mol to 100 mol of water with respect to 1 mol of the organometallic compound, or the amount of the acid used is 0.01 to 2 in terms of a molar ratio with respect to the organometallic compound, or a raw material solution It is preferable to add 10% by mass or less of an organic thickener.

The composition of the flaky glass preferably contains silica, silica-titania, silica-zirconia, and other silicate-based oxides containing other components, and the softening point (viscosity coefficient is 4 when the titania, zirconia, etc. are coated and heat-treated. (Temperature at 5 × 10 ⁷ poise) is more preferably 1100 ° C. or higher.
Disperse the flaky silica glass in water, slowly add a titanium oxysulfate aqueous solution and sulfuric acid, and heat it to coat the surface of the flaky substrate with a predetermined thickness of titania hydrate. It is preferable that a titania layer is formed by heating.

  The substrate on which the solution containing the organometallic compound capable of hydrolysis and polycondensation is applied is selected from stainless steel, gold, silver metal, glass or plastic, and the surface roughness is preferably less than 0.05 μm, It is more preferable to apply a liquid containing the organometallic compound to the substrate to form a thin liquid film of 0.06 to 50 μm, peel the gel film from the base material, and then sinter to produce a flaky substrate. .

  The thickness of the flaky substrate is 0.05 μm to 5 μm, the diameter of the flaky substrate is 10 μm to 8 mm, the aspect ratio is at least 5, or on the flaky substrate, titania Alternatively, it is preferable to coat zirconia and control the thickness in the range of 50 to 200 nm.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to obtain a pearly luster paper for ink jet recording that has a pearly luster with a beautiful and beautiful color tone, is excellent in color developability, and can provide a high-quality recorded matter without ink bleeding or printing unevenness.

  In the pearlescent pigment used in the present invention, the flaky transparent substrate can be produced from a solution containing an organometallic compound capable of hydrolysis and polycondensation.

  A solution containing an organometallic compound that can be hydrolyzed and polycondensed is applied on a substrate, dried to form a gel film, and then the gel film is peeled off from the substrate to which the gel film is attached. After that, it is sintered to produce flaky glass.

The organic metal compound capable of hydrolysis and polycondensation as a raw material used in the present invention may be basically any compound as long as it undergoes hydrolysis and dehydration condensation, but a metal alkoxide having an alkoxyl group is preferred. More specifically, methoxide such as silicon, titanium, aluminum, zirconium, phosphorus and boron, ethoxide, propoxide, butoxide and the like are used alone or as a mixture. Therefore, the composition of the flaky glass obtained by the present invention can be used as flaky glass having any composition such as pure silica, silica-titania, silica-zirconia, and silicate-based oxides containing other components. It can withstand the temperature when it is coated and heat-treated with titania, zirconia, etc., specifically, the softening point (temperature when the viscosity coefficient is 4.5 × 10 ⁷ poise) is 1100 ° C. or higher, The flaky substrate preferably contains 80% or more of silica by mass because a low refractive index material is more likely to obtain pearl luster. In general, silica glass is used.

  The solvent of the raw material solution containing the organometallic compound may be basically any solvent as long as it substantially dissolves the organometallic compound, but alcohols such as methanol, ethanol, propanol and butanol can be used. Are most preferred. The amount of the solvent used is 0.1 to 0.995, preferably 0.2 to 0.9, more preferably 0.3 to 0.85 in a volume ratio with respect to the total amount of the organometallic compound and the solvent. is there.

  Moisture is required for hydrolysis of the organometallic compound as a raw material. This may be neutral, acidic or basic, but in order to promote hydrolysis, it is preferable to use water acidified with hydrochloric acid, nitric acid, sulfuric acid or the like. The amount used is preferably in the range of 1 mol to 100 mol of water with respect to 1 mol of the organometallic compound. And the usage-amount of an acid is 0.01-2 by molar ratio with respect to an organometallic compound, Preferably it is 0.05-1.5.

  In addition, in order to change the characteristics of the raw material solution, for example, an organic thickener may be added to the solution in order to adjust the thickness of the solution applied to the substrate. However, if this addition amount is large, it may remain as a carbide on the thin film by the final heating, so it should be 10% by mass or less.

  In the present invention, a substrate to which a solution containing an organometallic compound that can be hydrolyzed and polycondensed is applied is made of a material such as a metal such as stainless steel, gold, or silver, glass, plastic, or the like having a smooth surface. As the smoothness, the surface irregularities are preferably less than 0.05 μm. A liquid containing the organometallic compound is applied to such a substrate to form a thin liquid film of 0.06 to 50 μm. When this film dries, it becomes a gel-like film and shrinks, but the substrate does not shrink, so that cracks occur in the film. After peeling the gel-like film from the substrate, it is sintered to produce a flaky substrate.

  Further, the surface smoothness of the flaky substrate produced by this method becomes very good by improving the smoothness of the substrate to which the solution is applied, and there is no level difference observed in the mica flakes.

  Moreover, about the dimension of the flaky base | substrate used, thickness is 0.05 micrometer-5 micrometers normally. If it is thicker than 5 μm, the difference in drying speed between the film portion on the free surface and the film portion in the vicinity of the substrate becomes too large, and the resulting flake-like substrate will be delaminated in the direction horizontal to the substrate . When such delamination occurs, the distribution of the film thickness of the obtained flaky substrate becomes wide and the quality as a product deteriorates. On the other hand, if the thickness is less than 0.05 μm, the adhesion between the substrate and the film becomes too large, the film does not peel from the substrate, and does not form a flake. The diameter of the flaky substrate produced according to the present invention is usually 10 μm to several mm, and its aspect ratio is at least 5, preferably at least 10.

  A pearlescent pigment having a bright reflective interference color can be easily produced by coating titania or zirconia on the flaky substrate thus obtained by a known method. By controlling the thickness of the titania and zirconia to be coated in the range of 50 to 200 nm, pearly luster such as silver, golden, red, magenta, blue and green can be obtained.

  One of the above known titania coating methods is as follows. A flaky substrate, for example, flaky silica glass, is dispersed in water, and a titanium oxysulfate aqueous solution and sulfuric acid are slowly added thereto and heated to coat the surface of the flaky substrate with a predetermined thickness of titania hydrate. When this is heated at about 1000 ° C., a titania layer is formed and exhibits a pearlescent reflection interference color.

Examples of the support used in the present invention include chemical pulps such as LBKP and NBKP, wood pulps such as GP, PGW, RMP, TMP, CTMP, CMP, CGP, and other pulps, waste paper pulp such as DIP, and the like. The main component is a pigment, a binder, a sizing agent, a fixing agent, a yield improver, a cationizing agent, a paper strength enhancer, etc. , Base paper manufactured by various devices such as twin wire paper machines, base paper provided with size press and anchor coat layer with starch, polyvinyl alcohol, etc. on base paper, art paper provided with coat layer on them, Coated paper such as coated paper and cast coated paper is also included. Such a base paper and coated paper may be provided with the coating layer according to the present invention as it is, or a calendar device such as a machine calendar, a TG calendar, or a soft calendar may be used for the purpose of controlling flattening. . The basis weight of the support is usually 40 to 300 g / m ² , but is not particularly limited.

  The ink receiving layer referred to in the present invention is a property such as absorptivity, image reproducibility and color for ink containing dyes and pigments used in commercially available ink jet recording apparatuses (ink jet printers, ink jet plotters, ink jet proofers, etc.). And a composition comprising a pigment and a binder satisfying the above as main components. Further, when applied to an ink jet recording system using a dye ink together, it is preferable to contain a cationic compound in addition to the above. Other additives include pigment dispersants, thickeners, leveling agents, colored dyes, colored pigments, fluorescent brighteners, antioxidants, surfactants, antifoaming agents, antifoaming agents, foaming agents, and penetrating agents. Various additives such as additives, mold release agents, preservatives, antibacterial agents, water resistance agents, wet paper strength enhancers, dry paper strength enhancers and pH adjusters may be added in appropriate combinations.

  In addition to the pearl luster pigment of the present invention, examples of the pigment used in the ink receiving layer include light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc carbonate, and chisan. White, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, colloidal alumina, pseudoboehmite, vapor phase silica, aluminum oxide such as α, β, γ, δ-, hydroxylated White inorganic pigments such as aluminum, alumina, lithopone, zeolite, hydrous halloysite, magnesium carbonate, magnesium hydroxide, white pigments such as styrene plastic pigment, acrylic plastic pigment, polystyrene, urea resin, organic pigment of melamine resin, etc. Use more than Can. Among these, porous inorganic pigments are preferable, and examples include porous synthetic amorphous silica, porous magnesium carbonate, and porous alumina. Particularly, porous synthetic amorphous silica having a large pore volume is preferable. Usually, the average particle size of these pigments is preferably in the range of 0.1 to 20 μm.

  Examples of the binder used in the ink receiving layer of the present invention include, as natural polymer substances, potato starch, sweet potato starch, wheat starch, tapioca starch, and starches such as corn starch, laminaran, seaweed mannan, funari, Irish moss. , Agar, algae, algae, etc. Vegetable mucilage such as gum, homopolysaccharide such as dextran, glucan, xanthan gum and levan, and microbial mucilage such as heterosaccharide such as succinoglucan, pullulan, curdlan and xanthan gum, glue, gelatin, casein And proteins such as collagen and the like.

  Semi-natural products (semi-synthetic products) include propylene glycol alginate, viscose, methylcellulose, ethylcellulose, methylethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, hydroxypropylethylcellulose, carboxymethylhydroxyethylcellulose. And fiber derivatives such as hydroxypropylmethylcellulose phthalate, modified gums such as carboxymethyl guar gum, hydroxypropyl guar gum, and hydroxyethyl guar gum, and processing or derivatives of the natural polymer substance.

  Processed starches that are semi-synthetic products include white-dextrin, yellow dextrin, bridish gum and other cultured starches, enzyme-modified dextrins and shardinger dextrin and other acid-modified dextrins, solubilized starch and other acid-degraded starches, and dialdehyde starch Oxidized starch such as modified and unmodified pregelatinized starch, starch starch, phosphate starch, fatty acid starch, sulfated starch, nitrated starch, xanthogenic starch, and starch starch such as carbamate starch, hydroxyalkyl starch, carboxy Etherified starch such as alkyl starch, sulfoalkyl starch, cyanoethyl starch, allyl starch, benzyl starch, carbamylethyl starch, and dialkylamino starch, methylol-crosslinked starch, hydroxyalkyl-crosslinked starch, phosphate-crosslinked starch, and dicarboxylic acid-crosslinked starch Such as cross-linking Powder, starch polyacrylamide copolymer, starch polyacrylonitrile copolymer, cationic starch polyacrylic ester copolymer, cationic starch vinyl polymer copolymer, starch styrene maleic acid copolymer, and starch polyethylene oxide copolymer And starch graft copolymers such as coalescence.

  Synthetic products include polyvinyl alcohol, silyl modified polyvinyl alcohol, partially acetalized polyvinyl alcohol, allyl modified polyvinyl alcohol, modified polyvinyl alcohol such as polyvinyl methyl ether, polyvinyl ethyl ether, and polyvinyl isobutyl ether, polyacrylate, polyacrylic acid Polyester saponification product, polymethacrylate, polyacrylic acid derivatives such as polyacrylamide and polymethacrylic acid derivatives, polyethylene glycol, polyethylene oxide, polyvinyl pyrrolidone, vinyl pyrrolidone vinyl acetate copolymer, styrene butadiene copolymer (SBR) ), Nitrile butadiene copolymer (NBR), styrene acrylate copolymer, styrene maleic acid copolymer, styrene croton Copolymers, and vinyl-containing copolymer chloride. The above binders may be used alone or in combination of two or more.

  The cationic compound used in the ink-receiving layer of the present invention forms an insoluble salt with a water-soluble direct dye that is a water-soluble ink dye component or a sulfonic acid group, a carboxyl group, an amine group, etc. in a water-soluble acid dye. Examples include compounds containing secondary amines, tertiary aminos or quaternary ammonium salts. The cationic compounds may be used alone or in combination of two or more.

  A water-soluble polyvalent metal salt can be used in the ink receiving layer of the present invention. Examples of the water-soluble polyvalent metal compound 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 sulfate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate hexahydrate, cupric chloride , Ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel ammonium sulfate hexa Hydrate, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum nitrate hexahydrate, ferrous bromide, ferrous chloride , Ferric chloride, ferrous sulfide, ferric sulfate, zinc bromide, zinc chloride, zinc nitrate hexahydrate, sulfite , Zinc salicylate, zirconium acetate, zirconium chloride, zirconium chloride octahydrate, hydroxy zirconium chloride, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate Sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, and the like.

  The water-soluble polyvalent metal salt is more preferably an organic acid polyvalent metal salt. Among organic acid polyvalent metal salts, organic sulfonic acid metal salts and organic sulfuric acid ester metal salts are preferable. For example, benzene sulfonic acid metal salts, naphthalene sulfonic acid metal salts, and the like are known. , Alkyl group, alkenyl group, hydroxyl group, mercapto group, nitro group, nitroso group, amino group, oxyamino group, hydrazino group, halogen group, aldehyde group, ketone group, carboxyl group. Moreover, you may have two or more types of different substituents. Of these, calcium toluenesulfonate, zinc toluenesulfonate, calcium phenolsulfonate, zinc phenolsulfonate, and zinc sulfosalicylate are preferable.

  The water-soluble polyvalent metal salt means a polyvalent metal salt that dissolves in 1% by mass or more in 20 ° C. water. The water-soluble polyvalent metal salt may be used alone or in combination of two or more.

  The layer structure of the ink receiving layer of the present invention may be a single layer or a laminate. In the case of a laminated structure, all the layers may be layers having the same composition, or may be a laminated structure with layers composed of other components. In the case of lamination, the titania-silica glass may be contained in any one layer or in two or more layers.

The coating amount of the ink receiving layer of the present invention, is preferably in the range of 1 to 40 g / m ^2. If the coating amount is less than 1 g / m ² , the ink absorption by the ink receiving layer is not sufficient, so that uneven absorption occurs, and the inkjet performance is adversely affected. On the other hand, if it exceeds 40 g / m ² , the adhesive strength between the ink receiving layer and the support is lowered.

  Examples of the ink receiving layer coating method on the support according to the present invention include a slide popper coating method, a curtain coating method, an extrusion coating method, an air knife coating method, a blade coating method, a roll coating method, a rod bar coating method, and Examples include a gravure coating method, a size press coating method, and a spray coating method. These coating methods can be performed on-machine or off-machine. Moreover, you may finish using a calendar after coating. Examples of the calendar method include a machine calendar method, a TG calendar method, a super calendar method, a soft calendar method, an embossed calendar method, and the like.

  The thickness of the inkjet recording medium of the present invention is preferably about 50 to 300 μm. If it exceeds 300 μm, the rigidity becomes high and the flexibility of the ink jet recording medium is lacking, so that the transportability in the ink jet recording apparatus is lowered. On the other hand, when the thickness is less than 50 μm, the printing characteristics (cockling, ink absorbability, etc.) may be adversely affected, and the rigidity of the ink jet recording medium is lowered, so that the transportability in the ink jet recording apparatus is lowered.

  The ink used for recording on the inkjet recording medium of the present invention is generally a recording liquid comprising the following colorant, solvent, and other additives.

  Examples of the colorant of the ink include direct dyes, basic dyes, reactive dyes, dyes such as water-soluble dyes represented by food colors, colored inorganic pigments such as carbon black, phthalocyanine organic pigments, and azo organic pigments And the like.

  Examples of the solvent for the ink include water and various water-soluble organic solvents. For example, alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, dimethylformamide, dimethylacetamide Amides such as acetone, diacetone alcohol, etc., ethers such as tetrahydrofuran, dioxane, polyalkylene glycols such as polyethylene glycol, polypropylene glycol, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol , 1,2,6-hexanetriol, alkylene such as thiodiglycol, hexylene glycol, diethylene glycol There 2-6 alkylene glycol, glycerol, ethylene glycol methyl ether, diethylene glycol methyl (or ethyl) ether, lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether, and the like. Among these many water-soluble organic solvents, polyhydric alcohols such as diethylene glycol, and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl ether and triethylene glycol monoethyl ether are preferable. Examples of other additives include a pH adjuster, a metal sequestering agent, an antifungal agent, a viscosity adjuster, a surface tension adjuster, a wetting agent, a surfactant, and a rust preventive agent.

  The ink jet recording medium of the present invention is not limited to use as an ink jet recording medium, and may be used as any recording medium that uses liquid ink during recording. For example, an ink sheet in which a heat-meltable ink mainly composed of a heat-meltable substance or a dye / pigment is coated on a thin support such as a resin film, high-density paper, or synthetic paper is heated from the back surface to remove the ink. Image transfer medium for thermal transfer recording that is transferred by melting, ink-jet recording medium that heat-melts heat-meltable ink to form fine droplets, flying recording, ink-jet recording medium that uses oil-soluble dye dissolved in solvent, photopolymerization And an image receiving medium corresponding to a photosensitive pressure-sensitive donor sheet using microcapsules enclosing a type monomer and a colorless or colored dye / pigment.

  The common point of these recording media is that the ink is in a liquid state at the time of recording. The liquid ink permeates or spreads in the depth direction or the horizontal direction on the ink absorption layer side of the recording medium until it is cured, solidified, or fixed. The various recording media described above require absorbency according to the respective methods, and the ink jet recording medium of the present invention may be used as the various recording media described above.

  Furthermore, the ink jet recording medium of the present invention may be used as a recording medium for heat-fixing toner of an electrophotographic recording method widely used in copying machines, printers, etc. It can also be used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, it is not limited to these Examples. Moreover, unless otherwise indicated, the part and% shown in an Example show the mass part and mass% of solid content or a substantial component.

<Production of titania-coated flaky pigment>
Commercially available silicon tetraethoxide, ethanol and water were mixed at a volume ratio of 1: 2: 1 and stirred at room temperature for about 24 hours. A stainless steel plate having a surface of 20 cm × 20 cm and a thickness of 1 mm was prepared as a base material. The previously prepared solution was formed on this substrate by dip coating and left in an atmosphere of 20 ° C. and 60% RH for 5 minutes. Thereafter, this was placed in an oven at 120 ° C. and dried for 2 minutes, and the gel film peeled off from the substrate was collected with a nylon brush. The collected flaky silica gel was heat-treated at 1000 ° C. for 2 hours to obtain flaky silica glass. When the surface of the flaky silica glass was observed with an electron microscope, no surface step was observed and the surface was smooth.

  15 g of this flaky silica glass was dispersed in 100 ml of water and kept at 80 ° C. To this, 100 g of a titanium oxysulfate aqueous solution corresponding to 12 g of titanium dioxide and 50 g of 50% sulfuric acid were slowly added. This was heated to boiling for about one and a half hours. While reacting, one drop of the slurry was taken and placed on a black background, and the interference color caused by the titania hydrate layer was observed. When this color turned reddish orange, boiling was stopped. The slurry was filtered and washed with water to remove the sulfuric acid and dried.

  The obtained titania hydrate-coated flake was heat-treated at 1000 ° C. for 1 hour to obtain a golden pearl luster pigment made of titania-coated flaky silica glass. The dimensions were about 0.7 μm in thickness and about 60 μm in average particle size. The thickness of the titania layer was about 85 nm.

<Production of support>
The support had a light calcium carbonate / heavy calcium carbonate / talc ratio of 10/10/100 parts of wood pulp consisting of 80 parts of LBKP (freeness 400 mlcsf) and 20 parts NBKP (freeness 450 mlcsf). After preparing 10 parts of 25 pigments, 0.10 parts of commercially available alkyl ketene dimer, 0.03 parts of commercially available cationic (meth) acrylamide, 0.80 parts of commercially available cationized starch and 0.40 parts of sulfuric acid band Paper making was performed using a machine at a basis weight of 90 g / m ² .

<Ink-receiving layer coating liquid A>
The ink receiving layer coating solution having the following composition was adjusted so as to have a solid content concentration of 16%.
Amorphous silica fine particles (Mizukasil P78A: average particle size 3.3μ: manufactured by Mizusawa Chemical Co., Ltd.)
100 parts Polyvinyl alcohol (R1130: manufactured by Kuraray Co., Ltd.) 20 parts Cationic dye fixing agent (Smileds resin 1001: manufactured by Sumitomo Chemical Co., Ltd.) 20 parts Titania-coated flake pigment 5 parts

On the support, the ink receiving layer A was applied and dried by a bar coater so that the dry coating amount was 10 g / m ^2, and the ink jet recording medium of Example 1 was obtained.

<Production of zirconia-coated flaky pigment>
Zirconium sulfate corresponding to 10 g of zirconium dioxide was dissolved in 300 ml of an aqueous solution whose pH was adjusted to 2.7 by adding urea in advance. 12 g of the flaky silica glass described in Example 1 was added thereto, heated to 90 ° C., and kept at this temperature for about 1 and a half hours while stirring well. Thereafter, the slurry was filtered, washed with water and dried. This was heat-treated at 800 ° C. for 1 hour. The thickness of the zirconia layer was about 80 nm.

<Ink-receiving layer coating solution B>
The ink receiving layer coating solution having the following composition was adjusted so as to have a solid content concentration of 16%.
Amorphous silica fine particles (Mizukasil P78A: average particle size 3.3μ: manufactured by Mizusawa Chemical Co., Ltd.)
100 parts Polyvinyl alcohol (R1130: manufactured by Kuraray Co., Ltd.) 20 parts Cationic dye fixing agent (Smileds resin 1001: manufactured by Sumitomo Chemical Co., Ltd.) 20 parts Zirconia-coated flaky pigment 5 parts

On the support, the ink receiving layer B was coated and dried by a bar coater so that the dry coating amount was 10 g / m ^2, and the ink jet recording medium of Example 2 was obtained.

<Ink-receiving layer coating solution C>
The ink receiving layer coating solution having the following composition was adjusted so as to have a solid content concentration of 16%.
Amorphous silica fine particles (Mizukasil P78A: average particle size 3.3μ: manufactured by Mizusawa Chemical Co., Ltd.)
100 parts Polyvinyl alcohol (R1130: manufactured by Kuraray Co., Ltd.) 20 parts Cationic dye fixing agent (Smileds resin 1001: manufactured by Sumitomo Chemical Co., Ltd.) 20 parts Titania-coated flake pigment 2.5 parts Zirconia-coated flake pigment 2.5 parts

On the support, the ink receiving layer C was coated and dried by a bar coater so as to have a dry coating amount of 10 g / m ² to obtain an ink jet recording medium of Example 3.

(Comparative Example 1)
<Ink-receiving layer coating solution D>
The ink receiving layer coating solution having the following composition was adjusted so as to have a solid content concentration of 16%.
Amorphous silica fine particles (Mizukasil P78A: average particle size 3.3μ: manufactured by Mizusawa Chemical Co., Ltd.)
100 parts Polyvinyl alcohol (R1130: manufactured by Kuraray Co., Ltd.) 20 parts Cationic dye fixing agent (Smiles resin 1001: manufactured by Sumitomo Chemical Co., Ltd.) 20 parts

On the support, the ink receiving layer D was coated and dried by a bar coater so that the dry coating amount was 10 g / m ^2, and an inkjet recording medium of Comparative Example 1 was obtained.

  As described above, the ink jet recording materials prepared in Examples and Comparative Examples were evaluated by the following evaluation methods, and the results are shown in Table 1.

<Evaluation of pearl gloss>
The unprinted part of the prepared inkjet recording medium was touched by hand and evaluated according to the following criteria.
○: Very high pearl luster.
Δ: Inferior to ○ but with a pearly luster.
X: Matte tone.

<Print density evaluation>
Each ink jet recording medium was subjected to black solid printing with an ink jet printer (PM750C manufactured by Seiko Epson Corporation), and the optical density was measured.

<Evaluation of ink absorbency>
Each inkjet recording medium was subjected to black solid printing with an inkjet printer (PM750C manufactured by Seiko Epson Corporation), and the ink absorbency was observed and evaluated according to the following criteria.
A: Good absorption without ink overflow or bleeding.
Δ: Slight ink overflow, but no problem in practical use.
X: Ink overflow is conspicuous and is not practical.

<Hand>
The unprinted part of the prepared inkjet recording medium was touched and evaluated.
○: The touch is smooth and the touch is very good.
Δ: Gives a slightly rough impression compared to ○, but is good.
X: The feel is rough.

  As can be seen from Table 1, in Examples 1 to 3 containing a pigment obtained by coating titania, zirconia or a mixture thereof on a flaky substrate, the pearly luster was excellent, and the printing density and touch were also good. It was. On the other hand, in Comparative Example 1 which does not contain a pigment obtained by coating titania or zirconia or a mixture thereof on a flaky substrate, the pearly luster is not sufficient, and the printing density, touch and the like are also inferior.

Claims (18)

  In pigments obtained by coating titania or zirconia or a mixture thereof on a flaky substrate, the pearlescent pigment obtained by using an organometallic compound that can be hydrolyzed and polycondensed as a starting material is contained in the ink receiving layer as the flaky substrate. An ink jet recording material characterized by comprising:   2. The ink jet recording material according to claim 1, wherein the flaky substrate is a glass containing 80% by weight or more of silica.   3. The ink jet recording material according to claim 2, wherein the organometallic compound is a metal alkoxide having an alkoxyl group.   4. The ink jet recording material according to claim 3, wherein the metal alkoxide is a single substance or a mixture of silicon, titanium, aluminum, zirconium, phosphorus, boron methoxide, ethoxide, propoxide and butoxide.   5. The ink jet recording material according to claim 4, wherein the composition of the flaky glass contains a silicate-based oxide containing silica, silica-titania, silica-zirconia and other components. 6. The ink jet recording material according to claim 5, wherein a softening point (temperature at which the viscosity coefficient is 4.5 × 10 ⁷ poise) upon covering and heat-treating titania, zirconia or the like is 1100 ° C. or more.   7. The ink jet recording material according to claim 1, wherein the solvent of the raw material solution containing the organometallic compound is at least one alcohol selected from methanol, ethanol, propanol and butanol. .   8. The ink jet recording material according to claim 7, wherein the amount of the solvent used is 0.1 to 0.995 by volume with respect to the total amount of the organometallic compound and the solvent.   9. The ink jet recording material according to claim 8, wherein the hydrolysis of the organometallic compound is acidic water selected from at least one of hydrochloric acid, nitric acid, and sulfuric acid.   10. The ink jet recording material according to claim 9, wherein the amount of water used in the hydrolysis is 1 mol to 100 mol of water with respect to 1 mol of the organometallic compound.   11. The ink jet recording material according to claim 10, wherein the amount of the acid used is 0.01 to 2 in molar ratio with respect to the organometallic compound.   12. The ink jet recording material according to claim 11, wherein 10% by mass or less of an organic thickener is added to the raw material solution.   The substrate to which the solution containing the organometallic compound capable of hydrolysis and polycondensation is applied is selected from stainless steel, gold, silver metal, glass or plastic, and has a surface roughness of less than 0.05 μm. The ink jet recording material according to claim 12.   Applying a liquid containing the organometallic compound to the substrate to form a thin liquid film of 0.06 to 50 μm, peeling the gel film from the base material, and then sintering to produce a flaky substrate The inkjet recording material according to claim 12, wherein   13. The ink jet recording material according to claim 12, wherein the thickness of the flaky substrate is 0.05 μm to 5 μm.   13. The ink jet recording material according to claim 12, wherein the diameter of the flaky substrate is from 10 [mu] m to 8 mm, and the aspect ratio is at least 5.   13. The ink jet recording material according to claim 12, wherein the flaky substrate is coated with titania or zirconia and the thickness thereof is controlled in the range of 50 to 200 nm.   Disperse the flaky silica glass in water, slowly add a titanium oxysulfate aqueous solution and sulfuric acid, and heat it to coat the surface of the flaky substrate with a predetermined thickness of titania hydrate. 2. The inkjet recording material according to claim 1, wherein a titania layer is formed by heating.