JP2005193622A - Inkjet recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording material which shows high photograph-like gloss; outstanding ink absorbency/water resistance; a successful curl balance without posing a problem of bend-cracking; and high productivity. <P>SOLUTION: In the inkjet recording material with ink receiving layers formed on a support, at least one of the ink receiving layers contains a resin binder having an inorganic fine particle with a secondary particle diameter of not more than 500 nm and a keto group; a chemical compound having not less than two primary amino groups in a molecule; and a water-miscible high boiling point organic solvent. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an inkjet recording material. More specifically, the coated surface is less likely to crack, has a photo-like gloss, is excellent in ink absorption and water resistance, has no problem of cracking, and has a curl temperature. The present invention relates to an ink jet recording material that is less dependent on humidity and excellent in paper feed stability and transportability in an ink jet printer and has less head rubbing.

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

  In recent years, recording materials that use extremely fine inorganic particles as a pigment and have a photo-like gloss have been known. For example, it has been proposed to use inorganic ultrafine particles such as gas phase method silica or wet method silica pulverized and dispersed to 500 nm or less as a pigment component of the ink receiving layer. For example, JP-A-3-56552, JP-A-10-119423, JP-A-2000-2111235, and JP-A-2000-309157 disclose examples of using vapor phase silica. JP-A-9-286165, JP-A-10-181190 Japanese Laid-Open Patent Publication No. 2001-277712 discloses an example of using pulverized sedimentation silica, and Japanese Laid-Open Patent Publication No. 2001-277712 discloses an example of using crushed gel silica. JP-A-62-174183, JP-A-2-276670, JP-A-5-32037, JP-A-6-199034 and the like disclose recording materials using alumina or alumina hydrate.

  However, when inorganic ultrafine particles are used, high gloss can be obtained, but the viscosity of the coating solution tends to be high, and since the coating is applied at a low solid content concentration, surface defects such as wind ripples and cracks during drying tend to occur. In particular, when a water-resistant support such as polyolefin resin-coated paper (laminated with polyolefin resin such as polyethylene on both sides of the paper) or polyester film is used to obtain high gloss and good texture, Since the ink cannot be absorbed, the ink absorbability of the ink receiving layer provided on the support is important. Therefore, it is necessary to apply a large amount of pigment with a reduced ratio of the binder to the inorganic fine particles, and defects occur during drying. It was easy.

  In order to prevent such surface defects, a method is known in which a coating solution containing a crosslinking agent is applied to a support and then dried under relatively mild conditions. For example, in JP-A-10-119423, 2000-27093, 2001-96900, etc., a boron compound such as boric acid, borate, or borax is used as a crosslinking agent for polyvinyl alcohol, and a coating solution is applied. A method is disclosed in which after cooling once to increase the viscosity of the coating solution, the coating solution is dried at a relatively low temperature. Aldehyde compounds, epoxy compounds, isocyanates, and the like have also been studied, but it is difficult to achieve both crosslinkability and various properties as an inkjet recording material. To date, crosslinking agents that surpass boron compounds The actual situation is not found. However, even when a boron compound is used as a cross-linking agent, a coating film often has a defect depending on the coating and drying conditions, and a coating failure may become noticeable with a slight change in drying temperature. In addition, since the water resistance is insufficient and the film quality becomes rigid, there are disadvantages such as so-called folding where the coating film breaks when the recording material is bent. Furthermore, since a long time is required especially in a drying process, there exists a problem that productivity cannot be made high.

  Further, as described above, it is necessary to apply a large amount of inorganic fine particles in order to maintain ink absorptivity capable of printing, but there is also a problem that the curl balance changes with temperature and humidity. Specifically, since the binder component swells with moisture under high humidity, the ink receiving layer side expands, and the side opposite to the ink receiving layer sandwiches the support and relatively shrinks. On the other hand, the binder component releases moisture under low humidity, so that the ink receiving layer side contracts and the opposite side relatively expands. The curl balance is one of the physical properties of a recording material, which is very important for output with an ink jet printer. If the physical properties are not compatible with the ink jet printer, the recording material is not conveyed and cannot be output, or the printer head contacts the recording material during the output, so-called head rubbing occurs. When the head rubbing occurs, if the image becomes dirty or severe, the printer head may be damaged, and improving the curling property is a very important issue.

  The methods for improving the curling property include (1) a method of providing a coating layer (so-called back coating layer) on the opposite side of the ink receiving layer across the support, and (2) a substance having high moisture retention in the ink receiving layer. (3) In the case where the support has a resin coated on both sides of the paper, there is a method of adjusting the curl balance by changing the thickness of the resin, etc. At present, these methods are used alone or in combination to improve the curling property. The most effective means of the method (1) is to make the backing layer the same as the ink receiving layer, but there are disadvantages in terms of productivity and handling. When the same coating solution is applied to both surfaces of the support, the low productivity is further reduced. Even if the same coating liquid is applied to both sides of the support, it is difficult to balance the friction coefficient on both sides of the recording material, and the transportability in the printer is deteriorated. In addition, the crackability of the recording material is also deteriorated. The cracking property becomes prominent mainly when the ink receiving layer is folded outward, and is greatly reduced when the ink receiving layer is folded inward. However, when the ink receiving layer coating solution is applied to both sides of the support, cracks are likely to occur regardless of which direction the substrate is bent. It is possible to avoid reducing the productivity by selecting a backing layer different from the ink receiving layer, and it is possible to balance the number of friction fluids by selecting the material. Since the swelling rate differs from that of the backing layer, it is difficult to achieve curl balance in the entire temperature and humidity range.

  In the method (2), urea is effective and effective in preventing cracks during coating and drying, but if added too much, the ink absorbability decreases due to swelling of urea, and the ink absorbency and curling property Both have not been satisfied. Water-miscible, high-boiling organic solvents are also very effective in improving curling properties. For example, the curling behavior of recording materials after printing without a border on an inkjet printer is very small compared to the recording material before printing. . This is because water-miscible high-boiling organic solvents such as glycerin and glycol compounds contained in the ink remain in the recording material, the moisture retention effect increases, and the humidity outside the recording material greatly affects the expansion and contraction of the recording material. This is the result of disappearance. Thus, although it is a water-miscible high-boiling organic solvent that is highly effective in improving curling properties, in the system using a boron compound as a crosslinking agent as described above, the main binder of polyvinyl alcohol and the boron compound There is a problem that cracking occurs during coating and drying because the binding is inhibited. For example, Japanese Patent Application Laid-Open No. 2002-316472 (Patent Document 1) describes a method for improving curling properties by adding a high-boiling organic solvent in a drying process.

  In the method (3), it is difficult to obtain a curl balance between the resin and the ink receiving layer in the entire temperature and humidity range, and it is only an auxiliary method.

  On the other hand, it is known to use a resin having a keto group for an ink jet recording material, for example, JP-A-63-176173, JP-A-10-157283 (Patent Document 2), JP-A-2000-52646, etc. Describes a method of using the polymer swelling type ink receiving layer as a main component. JP-B-4-15746, JP-A-2000-280600, 2001-72711, 2001-213045 (Patent Document 3), and 2003-301084 disclose a binder component of a porous ink receiving layer. The use of acetoacetyl-modified polyvinyl alcohol is described.

However, these prior arts include suppression of cracks in ink jet recording materials using inorganic ultrafine particles, imparting a photo-like high gloss, improved ink absorbency, improved water resistance, improved crack resistance, curl There is no description that satisfies the improvement of sex.
JP 2002-314672 A Japanese Patent Laid-Open No. 10-157283 JP 2001-213045 A

  An object of the present invention is to provide an ink jet recording material having a photo-like high gloss, excellent ink absorption, water resistance of a coating layer, no cracking problem, and good curl balance. It is.

The inventor conducted research to solve this problem,
(1) In a recording material in which an ink receiving layer is provided on a support, at least one of the ink receiving layers has a resin binder having an inorganic fine particle having an average secondary particle diameter of 500 nm or less and a keto group, and a primary amino group as a molecule. An ink jet recording material comprising a compound having two or more compounds therein and a water miscible high boiling point organic solvent
(2) The inkjet recording material according to (1) above, wherein the resin binder having a keto group is a modified polyvinyl alcohol having a keto group
(3) The inkjet recording material according to (1) or (2), wherein the compound having two or more primary amino groups in the molecule is a compound having two or more hydrazide groups in the molecule
(4) With the knowledge that a remarkable effect can be obtained by the inkjet recording material according to any one of (1) to (3) above, wherein the support is a non-absorbable support. The present invention has been completed.

  In the ink jet recording material, as described in the present invention in the ink receiving layer, inorganic fine particles having an average secondary particle diameter of 500 nm or less, a resin binder having a keto group, a compound having two or more primary amino groups in the molecule, and water By using a miscible high-boiling organic solvent, it has high gloss, high ink absorptivity, and high water resistance, and is excellent in curl balance without cracking.

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

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

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

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

  In the ink receiving layer of the present invention, the vapor phase method silica is used in the presence of a cationic compound, and the average secondary particle size of the vapor phase method silica is 500 nm or less, preferably 10 to 300 nm, more preferably 20 to 200 nm. Dispersed ones can be used. As a dispersion method, gas phase method silica and a dispersion medium are premixed by ordinary propeller stirring, turbine type stirring, homomixer type stirring, etc., and then a media mill such as a ball mill, a bead mill, a sand grinder, a high pressure homogenizer, an ultrahigh pressure, etc. It is preferable to perform dispersion using a pressure disperser such as a homogenizer, an ultrasonic disperser, a thin film swirl disperser, or the like. The average secondary particle diameter as used in the present invention refers to an average value of the particle diameters of the dispersed aggregated particles observed by observing the ink receiving layer of the obtained recording material with an electron microscope. It is.

  In the present invention, wet process silica pulverized to an average secondary particle diameter of 500 nm or less can also be preferably used. The wet process silica particles used in the present invention are preferably wet process silica particles having an average primary particle diameter of 50 nm or less, preferably 3 to 40 nm, and an average aggregate particle diameter of 5 to 50 μm. It is preferable to use wet method silica fine particles finely pulverized to an average secondary particle diameter of 500 nm or less, preferably about 20 to 200 nm in the presence of.

  Since the wet process silica produced by a normal method has an average aggregate particle diameter of 1 μm or more, it is used after being finely pulverized. As a pulverization method, a wet dispersion method in which silica dispersed in an aqueous medium is mechanically pulverized can be preferably used. At this time, the increase in the initial viscosity of the dispersion is suppressed, high concentration dispersion is possible, and the pulverization / dispersion efficiency is increased so that the particles can be further pulverized. Therefore, the oil absorption is 210 ml / 100 g or less, the average aggregated particle diameter It is preferable to use precipitated silica of 5 μm or more. By using a high-concentration dispersion, the productivity of recording paper is also improved. The oil absorption is measured based on the description of JIS K-5101.

  As a specific method for obtaining wet-process silica fine particles having an average secondary particle diameter of 500 nm or less according to the present invention, first, silica particles and a cationic compound are mixed in water (which may be added first or simultaneously). And each dispersion or aqueous solution may be mixed, and at least one dispersion device such as a sawtooth blade type dispersion device, a propeller blade type dispersion device, or a rotor stator type dispersion device is used. To obtain a preliminary dispersion. If necessary, an appropriate low boiling point solvent may be added. The higher the solid content concentration of the silica pre-dispersion, the better. However, since the dispersion becomes impossible when the concentration is too high, the preferred range is 15 to 40% by mass, and more preferably 20 to 35% by mass. Next, a wet method silica fine particle dispersion having an average secondary particle diameter of 500 nm or less is obtained by applying stronger mechanical means. As the mechanical means, a known method can be adopted, for example, a media mill such as a ball mill, a bead mill, a sand grinder, a high pressure homogenizer, a pressure disperser such as an ultra high pressure homogenizer, an ultrasonic disperser, a thin film swirl disperser, etc. Can be used.

  As the cationic compound used for the dispersion of the gas phase method silica and the wet method silica, a cationic polymer or a water-soluble metal compound can be used. As the cationic polymer, polyethyleneimine, polydiallylamine, polyallylamine, alkylamine polymer, JP-A-59-20696, JP-A-59-33176, JP-A-59-33177, JP-A-59-155088, Sho 60-11389, Sho 60-49990, Sho 60-83882, Sho 60-109894, Sho 62-198493, Sho 63-49478, Sho 63-115780, Shosho 63-280681, No. 1-40371, No. 6-234268, No. 7-125411, No. 10-193976, etc. The polymer having is preferably used. In particular, diallylamine derivatives are preferably used as the cationic polymer. In terms of dispersibility and dispersion viscosity, the molecular weight of these cationic polymers is preferably about 2,000 to 100,000, and particularly preferably about 2,000 to 30,000.

  Examples of the water-soluble metal compound include water-soluble polyvalent metal salts, and among them, a compound made of aluminum or a group 4A metal (for example, zirconium or titanium) in the periodic table is preferable. Particularly preferred is a water-soluble aluminum compound. As a water-soluble aluminum compound, for example, as an inorganic salt, aluminum chloride or a hydrate thereof, aluminum sulfate or a hydrate thereof, ammonium alum and the like are known. Furthermore, a basic polyaluminum hydroxide compound which is an inorganic aluminum-containing cationic polymer is known and preferably used.

The basic polyaluminum hydroxide compound has a main component represented by the following general formula 1, 2, or 3, for example, [Al ₆ (OH) ₁₅ ] ³⁺ , [Al ₈ (OH) ₂₀ ] ⁴⁺ , [Al ₁₃ (OH) ₃₄ ] ⁵⁺ , [Al ₂₁ (OH) ₆₀ ] ³⁺ , etc. is there.

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

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

  As the water-soluble compound containing a Group 4A element of the periodic table used in the present invention, a water-soluble compound containing titanium or zirconium is more preferable. Examples of the water-soluble compound containing titanium include titanium chloride and titanium sulfate. Examples of water-soluble compounds containing zirconium include zirconium acetate, zirconium chloride, zirconium oxychloride, hydroxy zirconium chloride, zirconium nitrate, basic zirconium carbonate, zirconium hydroxide, zirconium lactate, zirconium carbonate / ammonium, zirconium carbonate / potassium, zirconium sulfate. And zirconium fluoride compounds. In the present invention, the term “water-soluble” means that 1% by mass or more dissolves in water at room temperature and normal pressure.

  As the alumina used in the present invention, γ-alumina which is a γ-type crystal of aluminum oxide is preferable, and among them, a δ group crystal is preferable. Although γ-alumina can reduce the primary particles to about 10 nm, normally, secondary particle crystals of several thousand to several tens of thousands nm are averaged by ultrasonic waves, a high-pressure homogenizer, a counter collision type jet crusher, or the like. Those whose size is pulverized to a particle size of 500 nm or less, preferably about 20 to 300 nm can be used.

The alumina hydrate of the present invention is represented by a constitutive formula of Al ₂ O ₃ .nH ₂ O (n = 1 to 3). The case where n is 1 represents an alumina hydrate having a boehmite structure, and the case where n is greater than 1 and less than 3 represents an alumina hydrate having a pseudo boehmite structure. It can be obtained by a known production method such as hydrolysis of an aluminum alkoxide such as aluminum isopropoxide, neutralization of an aluminum salt with an alkali, hydrolysis of an aluminate. The average secondary particle diameter of the alumina hydrate used in the present invention is 500 nm or less, preferably 20 to 300 nm.

  The above-mentioned alumina and alumina hydrate used in the present invention are used in the form of a dispersion dispersed with a known dispersant such as acetic acid, lactic acid, formic acid, nitric acid and the like.

  In the present invention, a resin having a keto group is used as a binder for inorganic fine particles. The resin binder having a keto group can be synthesized by a method of copolymerizing a monomer having a keto group and another monomer. Specific examples of the monomer having a keto group include acrolein, diacetone acrylamide, diacetone methacrylate, acetoacetoxyethyl methacrylate, 4-vinylacetoacetanilide, acetoacetylallylamide, and the like. Further, a keto group may be introduced by a polymer reaction. For example, an acetoacetyl group can be introduced by a reaction between a hydroxy group and a diketene. Specific examples of the resin binder having a keto group include acetoacetyl-modified polyvinyl alcohol, acetoacetyl-modified cellulose derivatives, acetoacetyl-modified starch, diacetone acrylamide-modified polyvinyl alcohol, and resin binders described in JP-A-10-157283. Can be mentioned. In the present invention, modified polyvinyl alcohol having a keto group is particularly preferable. Examples of the modified polyvinyl alcohol having a keto group include acetoacetyl-modified polyvinyl alcohol and diacetone acrylamide-modified polyvinyl alcohol.

  The acetoacetyl-modified polyvinyl alcohol can be produced by a known method such as a reaction between polyvinyl alcohol and diketene. The degree of acetoacetylation is preferably from 0.1 to 20 mol%, more preferably from 1 to 15 mol%. The saponification degree is preferably 80 mol% or more, more preferably 85 mol% or more. As a polymerization degree, the thing of 500-5000 is preferable, and the thing of 1000-4500 is especially preferable.

  Diacetone acrylamide-modified polyvinyl alcohol can be produced by a known method such as saponification of a diacetone acrylamide-vinyl acetate copolymer. As content of a diacetone acrylamide unit, the range of 0.1-15 mol% is preferable, and also the range of 0.5-10 mol% is preferable. The saponification degree is preferably 85 mol% or more, and the polymerization degree is preferably 500 to 5,000.

  In the present invention, in addition to the resin binder having a keto group, another known resin binder may be used in combination. For example, cellulose derivatives such as carboxymethyl cellulose and hydroxypropyl cellulose, starch and various modified starches, gelatin and various modified gelatins, chitosan, carrageenan, casein, soy protein, polyvinyl alcohol, various modified polyvinyl alcohols, polyvinylpyrrolidone, polyacrylamide, etc. are required It can be used together depending on the situation. Furthermore, various latexes may be used in combination as the binder resin.

  In this case, it is preferable to use a resin binder having a keto group and a highly compatible resin binder in terms of gloss. When the modified polyvinyl alcohol having a keto group is used, complete or partially saponified polyvinyl alcohol or cation-modified polyvinyl alcohol can be preferably used in combination. In particular, those having a saponification degree of 80% or more and an average polymerization degree of 200 to 5000 can be preferably used.

  Examples of the cation-modified polyvinyl alcohol include polyvinyl alcohol having a primary to tertiary amino group or a quaternary ammonium group in the main chain or side chain of polyvinyl alcohol as described in JP-A-61-110483. It is.

  The amount of the resin binder to be used in combination is not particularly limited as long as the effect of the resin binder having a keto group and a compound having two or more primary amino groups in the molecule can be obtained.

  The smaller the total content of the resin binder, the smaller the void volume in the ink receiving layer, which is preferable in terms of increasing the ink absorbency.However, if the amount is too small, the ink receiving layer becomes brittle and surface defects such as cracks increase. Since glossiness falls, the range of 5-40 mass% is preferable with respect to inorganic fine particles, and 10-30 mass% is especially preferable.

  Next, a compound containing two or more primary amino groups of the present invention in the molecule will be described. The primary amino group of the present invention includes an aliphatic group, an aromatic group, a primary amino group bonded to a carbon atom of a heterocyclic group, and a primary amino group bonded to a nitrogen atom (that is, a terminal amino group of hydrazine). From the viewpoint of the thickening effect after mixing, a hydrazine-type amino group is preferable, and a hydrazide, semicarbazide, or carbohydrazide structure is particularly preferable. Specific examples of the compound having two or more primary amino groups bonded to carbon atoms include ethylenediamine, diethylenetriamine, triethylenediamine, metaxylenediamine, norbornanediamine, 1,3-bisaminomethylcyclohexane, and the like. Specific examples of the compound having two or more amino groups include hydrazine and salts thereof, carbohydrazide, succinic acid dihydrazide, adipic acid dihydrazide, citric acid trihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, and the like, Examples include a reaction product of polyisocyanate and hydrazine such as 4,4′-ethylene disemicarbazide and 4,4′-hexamethylene disemicarbazide, and a polymer hydrazide such as polyacrylic acid hydrazide. In particular, succinic acid dihydrazide and adipic acid dihydrazide are preferable in terms of water solubility and reactivity.

  Although there is no particular limitation on the content of the compound containing two or more primary amino groups in the molecule of the present invention, in terms of productivity and the characteristics of the ink receiving layer obtained, with respect to the resin binder having a keto group, The range of 0.1-50 mass%, and also 1-20 mass% is preferable.

  In the present invention, other known hardeners may be used in combination. When modified polyvinyl alcohol is used as the resin binder, the polyvinyl alcohol cross-linking agent (hardener) includes aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, and bis (2-chloroethyl). Urea), 2-hydroxy-4,6-dichloro-1,3,5-triazine, a compound having a reactive halogen as described in US Pat. No. 3,288,775, divinyl sulfone, US Pat. No. 3,635 , Compounds having reactive olefins as described in US Pat. No. 2,718,316, N-methylol compounds as described in US Pat. No. 2,732,316, isocyanates as described in US Pat. No. 3,103,437, US Pat. No. 3,017,280 and 2,983,611. Compounds, carbodiimide compounds as described in US Pat. No. 3,100,704, epoxy compounds as described in US Pat. No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane In addition, inorganic crosslinking agents such as chromium alum, zirconium sulfate, boric acid, borate, and borax can be used in combination.

  The water miscible high boiling point organic solvent referred to in the present invention will be described. The water miscibility in the present invention means that it can be uniformly mixed with water at a concentration of 1% by mass or more under normal temperature and pressure. In the present invention, the high boiling point means that the boiling point is higher than that of water, and preferably has a boiling point of 110 ° C. or higher. Examples of the water-miscible high-boiling organic solvent include ethylene glycol, diethylene glycol, triethylene glycol, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, polyethylene glycol and other glycol compounds, glycerin, 4-hydroxy-4-methyl-2 -Pentane, formamide, dimethylformamide and the like.

  The preferable content of the water-miscible high boiling point organic solvent is 0.4 to 25% by mass, more preferably 0.6 to 20% by mass with respect to the dry solid content of the ink receiving layer.

  The addition timing of the water-miscible high-boiling organic solvent in the present invention may be any process from the production of the coating liquid to the coating / drying completion process. It is preferable to add the water-miscible high-boiling organic solvent during the coating liquid production process because the viscosity of the coating liquid is lowered and the coating property is improved. In addition, the water-miscible high boiling point organic solvent and the other ink-receiving layer coating solution may be separated and coated using a coater head capable of simultaneous multi-layer coating, or other than the water-miscible high boiling point organic solvent. After the ink receiving layer coating solution is applied to the support, a water-miscible high boiling point organic solvent may be applied during the drying step.

  In the present invention, it is preferable that the coating liquid is applied to a support and then gelled and then dried. By the gelation step, an inkjet recording material having higher gloss and good ink absorbability can be obtained. In addition, since cracking does not occur even when dried at high temperatures, high productivity is obtained compared to a production method using polyvinyl alcohol and boric acid, gelled at low temperature, and then dried under relatively mild conditions. . Furthermore, since it is not necessary to use a boron compound such as boric acid, it is preferable in terms of environment. In addition, the gelation as used in the field of this invention refers to the state where a coating liquid does not flow with the wind which raises a viscosity and blows in a drying process.

  Since the gelation step in the present invention can be shortened by increasing the temperature, it is preferable to heat the support immediately after application. As a method of heating after applying to the support, a method of passing through high-temperature air, a method of adhering to a heat roll, a method using an infrared heating device, a microwave heating device, or the like can be used. The heating temperature depends on the composition of the coating solution such as the amount of the resin binder having a keto group and the amount of the compound having an amino group, but when the coating solution is aqueous, it is preferably 30 to 100 ° C, particularly 40 to 95 ° C. The range of is preferable. In general, the reaction between the keto group and the amino group proceeds relatively quickly, and in particular, the reaction between the keto group and the hydrazine or hydrazide group proceeds rapidly. From the viewpoint of productivity, the heating time is 1 second to 10 minutes. Is preferable, and 5 seconds to 7 minutes is more preferable.

The dry coating amount of the ink receiving layer of the present invention is in the range of 8 to 40 g / m ² , particularly 10 to 30 g / m ² as the solid content of the inorganic fine particles in terms of ink absorbability, ink receiving layer strength, and productivity. A range of m ² is preferred.

  In the present invention, it is preferable that the ink receiving layer further contains a cationic compound for the purpose of improving the water resistance of the ink dye. Examples of the cationic compound include the cationic polymer and the water-soluble metal compound mentioned in the description of the dispersion of silica. Examples of water-soluble metal compounds include water-soluble salts of metals selected from calcium, barium, manganese, copper, cobalt, nickel, iron, zinc, chromium, magnesium, tungsten, and molybdenum. Specifically, for example, calcium acetate, calcium chloride, calcium formate, calcium sulfate, barium acetate, barium sulfate, barium phosphate, manganese chloride, manganese acetate, manganese formate dihydrate, manganese ammonium sulfate hexahydrate, chloride chloride Dicopper, ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel sulfate Ammonium hexahydrate, nickel amidosulfate tetrahydrate, ferrous bromide, ferrous chloride, ferric chloride, ferrous sulfate, ferric sulfate, zinc bromide, zinc chloride, zinc nitrate hexa Hydrate, zinc sulfate, zinc p-phenolsulfonate, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate Nonahydrate, sodium phosphate, sodium tungsten citrate, 12 tungstophosphoric acid n-hydrate, dodecatungstosilicic acid 26-hydrate, molybdenum chloride, dodecamolybdophosphoric acid n-hydrate. Among these, a compound composed of a cationic polymer having a molecular weight of about 5,000 to 100,000 and aluminum or a group 4A metal (for example, zirconium or titanium) in the periodic table is preferable, and an aluminum compound is particularly preferable. One kind of cationic compound may be used, or a plurality of compounds may be used in combination.

  In the present invention, in addition to at least one ink receiving layer, the ink jet recording material may be further provided with a layer having another function such as an ink absorbing layer having a different structure or a protective layer.

  In the present invention, the ink receiving layer of each layer further includes a surfactant, a coloring dye, a coloring pigment, a fixing agent for the ink coloring agent, an ultraviolet absorber, an antioxidant, a pigment dispersant, an antifoaming agent, a leveling agent, an antiseptic. Various known additives such as an agent, a fluorescent brightening agent, a viscosity stabilizer, and a pH adjuster can also be added.

  Examples of the support used in the present invention include polyethylene, polypropylene, polyvinyl chloride, diacetate resin, triacetate resin, cellophane, acrylic resin, polyethylene terephthalate, polyethylene naphthalate and other water resistant supports such as polyolefin resin-coated paper, Water-absorbing supports such as high-quality paper, art paper, coated paper, cast coated paper and the like are used. A water resistant support is preferably used. Among water-resistant supports, polyolefin resin-coated paper is particularly preferable. The thickness of these supports is preferably about 50 to 250 μm.

  When using a support, particularly a film or resin-coated paper which is a water-resistant support, it is preferable to provide a primer layer mainly composed of a natural polymer compound or a synthetic resin on the surface on which the ink receiving layer is provided. The primer layer provided on the support is mainly composed of natural polymer compounds such as gelatin and casein and synthetic resins. Examples of such synthetic resins include acrylic resins, polyester resins, vinylidene chloride, vinyl chloride resins, vinyl acetate resins, polystyrene, polyamide resins, polyurethane resins, and the like. The primer layer is provided on the support with a film thickness (dry film thickness) of 0.01 to 5 μm. Preferably it is the range of 0.01-2 micrometers.

  Various back coat layers can be coated on the support in the present invention for writing property, antistatic property, transportability, curl resistance and the like. An inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, latex, a pigment, a curing agent, a surfactant, and the like can be appropriately combined in the backcoat layer.

  When the ink receiving layer coating solution is applied to a film support or resin-coated paper, corona discharge treatment, flame treatment, ultraviolet irradiation treatment, plasma treatment or the like is preferably performed prior to coating.

  In the present invention, a known coating method can be used as a coating method of each layer constituting the ink receiving layer. For example, there are a slide bead method, a curtain method, an extrusion method, an air knife method, a roll coating method, a rod bar coating method, and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the content of this invention is not restricted to an Example. In addition, a part and% show a mass part and the mass%.

<Preparation of polyolefin resin-coated paper support>
A 1: 1 mixture of hardwood bleached kraft pulp (LBKP) and softwood bleached sulfite pulp (NBSP) was beaten to 300 ml with Canadian Standard Freeness to prepare a pulp slurry. As a sizing agent, alkylketene dimer is 0.5% to pulp, polyacrylamide is 1.0% to pulp, and cationized starch is 2.0% to pulp. Polyamide epichlorohydrin resin is 0 to pulp. 0.5% was added and diluted with water to make a 1% slurry. This slurry was made with a long paper machine to a basis weight of 170 g / m ² , dried and conditioned to obtain a polyolefin resin-coated paper base paper. A polyethylene resin composition in which 10 parts of anatase-type titanium is uniformly dispersed is melted at 320 ° C. with respect to a resin of 100 parts of low density polyethylene having a density of 0.918 g / cm ³ , at 320 ° C. Extrusion coating was carried out to a thickness of 35 μm, and extrusion coating was performed using a cooling roll having a finely roughened surface. Melted at similarly 320 ° C. The blend resin composition of the low density polyethylene resin 30 parts of a density 0.962 g / cm 70 parts high density polyethylene resin of ³ and a density 0.918 g / cm ³ on the other surface, the thickness The film was extrusion-coated to a thickness of 30 μm and extrusion-coated using a cooling roll having a rough surface.

The polyolefin resin-coated paper surface was subjected to a high-frequency corona discharge treatment, and then a primer layer having the following composition was applied and dried so that gelatin was 50 mg / m ² (about 0.05 μm) to prepare a support.

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

<Recording sheet 1>
4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight 9,000) and 100 parts of vapor phase method silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g) were added to water to prepare Preliminary Dispersion 1, and then high pressure A silica dispersion 1 having a solid content of 20% was produced by treatment with a homogenizer. The silica dispersion 1 and other chemicals dissolved in water were mixed at 40 ° C. to prepare an ink receiving layer coating solution 1 having the following composition. The silica particles are coated on the support with a wire bar so that the coated amount of silica particles is 20 g / m ² , first heated at 80 ° C. for 15 seconds to gel the coating solution, and then air at 80 ° C. and 55 ° C. Were sequentially sprayed and dried. In addition, the average secondary particle diameter of the silica fine particle by electron microscope observation was 80 nm.
<Ink-receiving layer coating solution 1>
Silica dispersion 1 (as silica solid content) 100 parts acetoacetyl-modified polyvinyl alcohol 23 parts (acetoacetylation degree 3%, saponification degree 98%, average polymerization degree 2500)
Adipic acid dihydrazide 1 part Glycerin 5 parts

<Recording sheet 2>
A recording sheet 2 was prepared in the same manner as the recording sheet 1 except that glycerin was changed to diethylene glycol in the recording sheet 1 described above. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 3>
Recording sheet 3 was prepared in the same manner as recording sheet 1 except that 5 parts of glycerin in recording sheet 1 was changed to 3 parts of glycerin, 0.75 part of diethylene glycol, and 1.25 parts of triethylene glycol mono n-butyl ether. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 4>
A recording sheet 4 was produced in the same manner as the recording sheet 1 except that glycerin was changed to 4-hydroxy-4-methyl-2-pentane in the recording sheet 1 described above. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 5>
Recording sheet 5 was produced in the same manner as recording sheet 1 except that the amount of glycerin added in recording sheet 1 was changed from 5 parts to 0.7 parts. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 6>
A recording sheet 6 was produced in the same manner as the recording sheet 1 except that the amount of glycerin added in the recording sheet 1 was changed from 5 parts to 10 parts. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 7>
A recording sheet 7 was prepared in the same manner as the recording sheet 1 except that 5 parts of glycerin in the recording sheet 1 was changed to 0.8 part of glycerin, 0.2 part of diethylene glycol and 0.3 part of triethylene glycol mono n-butyl ether. . In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 8>
4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight 9,000) and 100 parts of precipitated silica (oil absorption 200 ml / 100 g, average primary particle size 16 nm, average aggregated particle size 9 μm) are added to water, and a sawtooth blade type Preliminary dispersion 8 was prepared using a disperser (blade peripheral speed 30 m / sec). Next, the obtained preliminary dispersion 8 was treated with a bead mill to obtain a silica dispersion 8 having a solid concentration of 30%. The silica dispersion 8 and other chemicals dissolved in water are mixed at 40 ° C. to prepare an ink-receiving layer coating liquid 8 having the following composition, so that the silica particle coating amount is 20 g / m ^2. The recording sheet 8 was obtained by applying the support on the support with a wire bar and drying in the same manner as the recording sheet 1. In addition, the average secondary particle diameter of the silica fine particles was 100 nm as observed with an electron microscope.
<Ink-receiving layer coating solution 8>
Silica dispersion 8 (as silica solid content) 100 parts acetoacetyl-modified polyvinyl alcohol 16 parts (degree of acetoacetylation 3%, degree of saponification 98%, average degree of polymerization 2500)
Adipic acid dihydrazide 1 part Glycerin 5 parts

<Recording sheet 9>
Nitric acid (2 parts) and pseudo boehmite (average primary particle size 14 nm) were added to water, and an alumina hydrate dispersion with a solid content concentration of 20% was prepared using a sawtooth blade type disperser. This alumina hydrate dispersion and other chemicals dissolved in water were mixed at 30 ° C. to prepare an ink receiving layer coating solution 9 having the following composition, so that the coating amount of alumina hydrate particles was 40 g / m ² . The recording sheet 9 was obtained by coating the support with a wire bar and drying in the same manner as the recording sheet 1. In addition, the average secondary particle diameter of the alumina hydrate particles was 80 nm as observed with an electron microscope.
<Ink-receiving layer coating solution 9>
Alumina hydrate dispersion (as alumina hydrate solid content) 100 parts acetoacetyl-modified polyvinyl alcohol 12 parts (acetoacetylation degree 3%, saponification degree 98%, average polymerization degree 2500)
Adipic acid dihydrazide 1 part Glycerin 5 parts

<Recording sheet 10>
Except for changing the binder component of the ink receiving layer coating solution 1 to 25 parts of diacetone acrylamide-modified polyvinyl alcohol (diacetone acrylamide modification degree 5 mol%, saponification degree 98 mol%, polymerization degree 1700), the recording sheet 1 and A recording sheet 10 was obtained in the same manner. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 11>
A recording sheet 11 was obtained in the same manner as the recording sheet 1 except that the adipic acid dihydrazide in the ink receiving layer coating solution 1 was changed to 0.7 part of succinic acid dihydrazide. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 12>
The ink receiving layer coating solution 1 is coated on the support with a wire bar so that the silica particle coating amount is 20 g / m ^2, and then cooled at 10 ° C. for 60 seconds to increase the viscosity of the coating solution. Next, 40 ° C. wind was blown and dried to obtain a recording sheet 12.

<Recording sheet 13>
Recording was performed except that the binder component of the coating liquid 1 for ink-receiving layer was changed to 23 parts of partially saponified polyvinyl alcohol (saponification degree 88 mol%, polymerization degree 3500), adipic acid dihydrazide was removed, and 4 parts of boric acid was added. In the same manner as in the sheet 1, an ink receiving layer coating solution 13 was obtained. The receiving layer coating solution 13 was applied and dried in the same manner as the recording sheet 1 to obtain a recording sheet 13. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 14>
The ink receiving layer coating solution 13 is coated on the support with a wire bar so that the silica particle coating amount is 20 g / m ^2, and then cooled at 10 ° C. for 60 seconds to increase the viscosity of the coating solution. Next, 40 ° C. wind was blown and dried to obtain a recording sheet 14. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 15>
A recording sheet 15 was obtained in the same manner as the recording sheet 14 except that glycerin was removed from the ink receiving layer coating solution 13. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 16>
Recording was performed except that the binder component of the ink receiving layer coating solution 8 was changed to 17 parts of partially saponified polyvinyl alcohol (saponification degree: 88 mol%, polymerization degree: 3500), adipic acid dihydrazide was removed, and 2 parts of boric acid was added. In the same manner as in the sheet 8, an ink receiving layer coating liquid 16 was obtained. The receiving layer coating solution 16 was applied and dried in the same manner as the recording sheet 1 to obtain a recording sheet 16. In addition, the average secondary particle diameter of the silica fine particles was 100 nm as observed with an electron microscope.

<Recording sheet 17>
The ink receiving layer coating liquid 16 is coated on the support with a wire bar so that the silica particle coating amount is 20 g / m ^2, and then cooled at 10 ° C. for 60 seconds to increase the viscosity of the coating liquid. Next, 40 ° C. wind was blown and dried to obtain a recording sheet 17. In addition, the average secondary particle diameter of the silica fine particles was 100 nm as observed with an electron microscope.

<Recording sheet 18>
A recording sheet 18 was obtained in the same manner as the recording sheet 17 except that glycerin was removed from the ink receiving layer coating liquid 16. In addition, the average secondary particle diameter of the silica fine particles was 100 nm as observed with an electron microscope.

<Recording sheet 19>
The binder component of the ink receiving layer coating liquid 9 was changed to 12 parts of partially saponified polyvinyl alcohol (saponification degree 88 mol%, polymerization degree 3500), except that adipic acid dihydrazide was removed and 0.2 part of boric acid was added. In the same manner as in the recording sheet 9, an ink receiving layer coating solution 19 was obtained. The receiving layer coating solution 19 was applied and dried in the same manner as the recording sheet 1 to obtain a recording sheet 19. In addition, the average secondary particle diameter of the alumina hydrate particles was 80 nm as observed with an electron microscope.

<Recording sheet 20>
The ink receiving layer coating liquid 19 is coated on the support with a wire bar so that the silica particle coating amount is 20 g / m ^2, and then cooled at 10 ° C. for 60 seconds to increase the viscosity of the coating liquid. Next, 40 ° C. wind was blown and dried to obtain a recording sheet 20. In addition, the average secondary particle diameter of the alumina hydrate particles was 80 nm as observed with an electron microscope.

<Recording sheet 21>
A recording sheet 21 was obtained in the same manner as the recording sheet 20 except that glycerin was removed from the ink receiving layer coating liquid 19. In addition, the average secondary particle diameter of the alumina hydrate particles was 80 nm as observed with an electron microscope.

<Recording sheet 22>
A recording sheet 22 was obtained in the same manner as in the recording sheet 1 except that glycerin was removed from the ink receiving layer coating solution 1. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 23>
A recording sheet 23 was obtained in the same manner as the recording sheet 1 except that glycerin was changed to ethyl alcohol (boiling point 78.3 ° C.) in the ink receiving layer coating liquid 1. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

<Recording sheet 24>
A recording sheet 24 was obtained in the same manner as the recording sheet 1 except that glycerin was changed to acetone (boiling point 56.5 ° C.) in the ink receiving layer coating solution 1. In addition, the average secondary particle diameter of the silica fine particles was 80 nm as observed with an electron microscope.

  The following evaluation was performed about each obtained inkjet recording sheet. The results are shown in Table 1.

<Evaluation of cracks on the coated surface>
The coated surface of the coated and dried ink receiving layer was observed and evaluated according to the following criteria.
○: There is no crack at all and the coated surface is uniform.
Δ: Small cracks that are difficult to distinguish visually are generated.
X: A large crack that can be clearly identified visually is generated.

<Glossiness of white paper part>
The glossiness of the blank paper before printing on the recording sheet was observed obliquely and evaluated according to the following criteria.
○: Glossiness as high as that of color photographs.
Δ: Slightly glossy.
X: There is no glossiness.

<Ink absorbability>
Red, blue, green, and black solid printing with a commercially available inkjet printer (Epson, PM-880C). Immediately after printing, the amount of ink transferred onto the PPC paper by lightly pressing the PPC paper over the print section. The degree of was observed visually. Evaluation was made according to the following criteria.
○: Not transferred.
Δ: A thin transfer is observed on the entire printed portion.
X: A dark transfer is observed over the entire printed part.

<Water resistance of ink receiving layer>
Water droplets were dropped on the surface of the recording sheet and left for 1 minute, then the surface was rubbed to observe the surface state. Note that the measurement was not performed on the recording sheet surface that originally had cracks. (Indicated in the table is-)
◯: No change Δ: Part of the ink receiving layer is scraped off, resulting in a reduced gloss.
X: Most of the ink receiving layer is scraped off.

<Crackability>
When an unprinted recording sheet was wound around a 1-inch roll with the printing surface facing upward, it was observed whether or not the surface was cracked. It should be noted that evaluation was not possible with respect to the case where cracks were originally generated on the surface of the recording sheet or where the cracks could not be confirmed due to the matte tone. (Indicated in the table is-)
○: No cracking occurs.
X: Cracking occurs.

<Curl properties>
The unprinted recording sheet was cut into A4 size, and left still horizontally with the printing surface facing up on a smooth table. H. , 23 ° C. 50% R.V. H. , 32 ° C. 80% R.V. H. After adjusting the humidity for 24 hours under the above conditions, how much the four corners were lifted from the table was measured with a ruler. When the four corners are bent on the back side of the printing surface, the height of the floating with the printing surface down was measured. For the sake of convenience, the four corners are lifted up when the print surface is up, and the negative is printed when the four corners are up when the print surface is down. The curl properties thus obtained were determined according to the following criteria. Note that the measurement was not performed on the recording sheet surface that originally had cracks. (Indicated in the table is-)
A: The curl value is within the range of -2 cm to 0 cm under each temperature and humidity condition.
A: The curl value is within a range of −5 cm to 0 cm under each temperature and humidity condition.
(Triangle | delta): The value of curl exists in the range of -10cm-3cm in each temperature and humidity conditions.
X: The value of minus curl is less than −10 cm or the value of plus curl is larger than 3 cm under each temperature and humidity condition.

  As an application example of the present invention, in addition to conventional applications, high-definition photo-like printed matter can be produced with an ink jet printer without rubbing the head even under conditions of lower temperature and lower humidity, or conversely, higher temperature and humidity. . Further, the distance between the ink jet recording material and the ink jet printer (so-called head gap) can be shortened to achieve higher speed and higher image quality.

Claims (4)

In a recording material in which an ink receiving layer is provided on a support, at least one of the ink receiving layers has inorganic fine particles having an average secondary particle diameter of 500 nm or less, a resin binder having a keto group, and two primary amino groups in the molecule. An ink jet recording material comprising the above-described compound and a water-miscible high-boiling organic solvent. The inkjet recording material according to claim 1, wherein the resin binder having a keto group is a modified polyvinyl alcohol having a keto group. The inkjet recording material according to claim 1 or 2, wherein the compound having two or more primary amino groups in the molecule is a compound having two or more hydrazide groups in the molecule. The inkjet recording material according to claim 1, wherein the support is a non-water-absorbing support.