JP2013248736A - Inkjet recording material and method for manufacturing inkjet recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high gloss inkjet recording material that does not cause cracks and bend-breakage and that can form a high-density image even with a pigment ink.SOLUTION: An inkjet recording material has an ink receiving layer on a support body. The ink receiving layer includes a UV cross-linked resin, an inorganic pigment and glidants. The glidants is univalent or divalent inorganic acid, or inorganic salts thereof.

Description

  The present invention relates to an inkjet recording material and a method for producing the inkjet recording material.

Inkjet recording is free of noise and can be printed at high speed, and has been adopted rapidly for terminal printers in recent years. Also, by using a plurality of ink nozzles, it is easy to perform multicolor recording, and multicolor ink jet recording is performed by various ink jet recording methods.
In particular, as an apparatus for creating hard copies of image information such as characters, various figures and photographs created by a computer, the use of an ink jet printer capable of forming a complex image quickly and accurately has attracted attention. In recent years, with the rapid spread of digital cameras, digital photographic images have become familiar and inkjet printers equipped with a photographic-only mode and ink for outputting these images with an inexpensive inkjet printer are also rapidly spreading.

  In particular, for inkjet printers for professionals and high amateurs (photo enthusiasts) who handle photography and graphics, photographic pigment ink products are the mainstream. In general, pigment inks in which the colorant is present in a solid form in a solvent have the advantage of being resistant to light degradation and having a fast time to color stabilization after printing, so the needs of professionals and photo enthusiasts (output Rather than keeping photos in photo albums, they are required to be viewed on indoor and outdoor frames as art works, so high image light resistance is required. Therefore, it is preferable to use an ink having a short time for the color to stabilize.

The photographic pigment ink is mainly made of a pigment having a diameter of several μm and having a particle diameter reduced from several tens of nanometers to several hundreds of nanometers in order to obtain glossiness of the ink. On the other hand, inkjet glossy paper for receiving photographic pigment ink needs to have a function of fastening photographic pigment on the paper surface and allowing solvent to quickly penetrate into the paper in order to increase image density.
Therefore, inkjet glossy paper required to increase the image density of photographic pigment inks requires a porous layer type recording material that has no cracks or cracks on the paper surface and has fine voids that allow only solvent to penetrate. It is done.

  As a porous layer type recording material, a recording material that uses extremely fine inorganic particles as a pigment and has a photo-like gloss has been proposed. 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, Japanese Patent Publication No. 3-56552 of Patent Document 1, Japanese Patent Application Laid-Open No. 10-119423 of Patent Document 2, and Japanese Patent Application Laid-Open No. 2000-212235 of Patent Document 3 disclose examples of using vapor phase silica. JP-A-9-286165 of Patent Document 5 and JP-A-10-181190 of Patent Document 6 disclose examples of using pulverized sedimentation silica, and JP-A-2001-277712 of Patent Document 7. The gazette discloses an example of using crushed gel silica.
Also, Japanese Patent Application Laid-Open No. 62-174183, Japanese Patent Application Laid-Open No. 62-174183, Japanese Patent Application Laid-Open No. 2-276670, Japanese Patent Application Laid-Open No. 5-32037, Japanese Patent Application Laid-Open No. 5-32037, Japanese Patent Application Laid-Open No. Hei 6-199034. Japanese Laid-Open Patent Publication No. 2002-254804 discloses a recording material using alumina or alumina hydrate as inorganic fine particles.

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 reduce the ratio of the binder to the inorganic fine particles and apply a large amount of the inorganic fine particles. Not only are defects more likely to occur at times, but also cracks that occur when handling recording materials (a phenomenon in which cracks occur where they are bent) have become a problem.

In order to prevent such surface defects, a method is known in which a coating liquid containing a crosslinking agent is applied to a support and then dried under relatively mild conditions.
For example, in Japanese Patent Application Laid-Open No. 2000-27093 of Patent Document 13 and Japanese Patent Application Laid-Open No. 2001-96900 of Patent Document 14, a boron compound such as boric acid, borate, or borax is used as a crosslinking agent for polyvinyl alcohol. A method is disclosed in which it is applied and cooled once to increase the viscosity of the coating solution and then dried at a relatively low temperature.

However, when the coating solution is dried at a low temperature, since the drying efficiency is low, the drying time must be lengthened, resulting in a decrease in productivity. In addition, surface defects may become prominent with a slight change in the drying temperature, and if the drying temperature rises, the surface will crack.
Moreover, since boric acid has reproductive toxicity, it is preferable to avoid using them.

Also known are aldehyde compounds and epoxy compounds as crosslinking agents, isocyanates, and titanium salts and zirconium salts as metal salts. However, when these cross-linking agents are mixed in the coating solution, the production yield is significantly reduced because the viscosity of the coating solution increases rapidly with time. That is, in the conventional technique in which a coating liquid containing such a crosslinking agent is applied to a support, the application / drying conditions are restricted, resulting in a decrease in productivity.

On the other hand, in JP-A-63-176173 of Patent Document 15, JP-A-10-157283 of Patent Document 16, and JP-A 2003-335043 of Patent Document 17, a resin having an acetoacetyl group is used for inkjet. It is disclosed for use in recording materials.
However, if an inorganic pigment with a small primary particle size is used to obtain a high glossy and high ink absorbing ink jet recording material, cracks and cracks are likely to occur, and in addition, it is satisfactory in terms of improving productivity. It was not reached.

In addition, examples of the ink-receiving layer that do not use a crosslinking agent include those disclosed in JP 2005-349613 A and JP 2005-349615 A in Patent Document 18 and polymers and inorganic fine particles having an acetoacetyl group. Ink-jet recording materials that are coated with an ink-receptive layer coating solution containing a basic polyaluminum hydroxide compound on a support and irradiated with ultraviolet rays before drying are free from defects such as cracks due to high-temperature and high-speed drying. It is disclosed that the glossiness is as high as that of the ink, and that a cationic compound may be contained in order to improve the water resistance of the ink dye.

However, the image density of these ink jet recording materials may decrease when pigment ink is used, and particularly when a color photographic image is formed, the image quality greatly decreases due to a slight decrease in image density. A high-quality photographic image cannot be formed, and in addition, in order to prevent cracking of the ink-jet receiving layer, a large amount of ultraviolet rays is required, and the problem of deterioration of the base material of the ink-jet receiving paper due to the ultraviolet rays Since ultraviolet irradiation requires a large amount of power, there is a problem that a large amount of power is consumed at the time of manufacturing, resulting in an increase in environmental load (increase in CO ₂ emissions) and manufacturing cost.

  Accordingly, an object of the present invention is to provide an ink jet recording material which is free from cracks and cracks, has high gloss, and can form a high density image even when a pigment ink is used.

As a result of intensive studies by the present inventors, the ink receiving layer contains an ultraviolet-crosslinkable resin and an ink receiving layer coating liquid containing an inorganic pigment, and the ink receiving layer coating liquid is gelled so that the ink receiving layer receives ink. The voids between the inorganic pigment particles immediately after application of the layer coating liquid are not crushed during drying, the surface is smooth, and the ink dispersion has high absorbency, and further prevents aggregation of the ink pigment particles. Thus, the inventors have found that an image with a high density can be formed, and have completed the present invention.
That is, the said subject is solved by following (1)-(6) of this invention.
(1) “An ink jet recording material having an ink receiving layer on a support, the ink receiving layer containing an ultraviolet crosslinking resin, an inorganic pigment, and a smoothing agent. An inkjet recording material characterized by being a divalent or divalent inorganic acid or an inorganic salt thereof, "
(2) "The ink jet recording material according to item (1), wherein the ink receiving layer contains a smoothing agent in an amount of 0.3 wt% to 7 wt%";
(3) “The inkjet recording material according to (1) or (2), wherein the inorganic acid or inorganic salt thereof is hydrochloric acid, sulfuric acid, amidosulfuric acid or a salt thereof” ,
(4) The inkjet according to any one of items (1) to (3), wherein the ultraviolet crosslinking resin has an acetoacetyl group, an acryloyl group, or a stilbazonium group. Recording material ",
(5) "The inkjet recording material according to any one of (1) to (4), wherein the inorganic pigment has an average secondary particle size of 500 nm or less",
(6) “The method for producing an ink jet recording material according to any one of items (1) to (5)”, wherein an ink-receiving layer coating liquid is applied to a support and reduced. Before the ink is dried, the coating liquid is irradiated with ultraviolet light, and the ink receiving layer coating liquid contains a resin that is crosslinked by ultraviolet irradiation, an inorganic pigment, and a smoothing agent. Production method".

  As will be understood from the following detailed and specific description, according to the present invention, the gap between the inorganic pigment particles immediately after application of the ink-receiving layer coating liquid is applied after coating such as high-temperature high-speed drying including crosslinking treatment. Even with the treatment, the surface is smooth and has high ink absorbability without being crushed during drying, and further, aggregation of pigment particles is prevented, and a high-quality photographic image with a high density can be formed.

The ink jet recording material of the present invention will be described in detail.
The inkjet recording material of the present invention has an ink receiving layer containing an ultraviolet crosslinking resin, an inorganic pigment, and a smoothing agent, and the smoothing agent is a monovalent or divalent inorganic acid or an inorganic salt thereof. It is.

<Smoothing agent>
The smoothing agent of the present invention preferably does not promote aggregation of the coexisting inorganic fine particles, and does not promote aggregation of the ink pigment in the inkjet ink to lower the image density. It is preferable that the reaction does not cause a discoloration or color change by a certain reaction. This smoothing agent uses a heat-resistant gel as the ink-receiving layer coating liquid and highly stabilizes the dispersion of inorganic pigment particles, so that even after drying at a high temperature and high speed, the ink-receiving layer coating liquid immediately after application. Prevents the voids between the inorganic pigment particles from collapsing, prevents aggregation of the pigment particles applied to the ink receiving layer, and achieves uniform dispersion of the inorganic pigment in the coating layer, and uniform coating layer itself By applying the coating, it suppresses the occurrence of spots due to uneven coating of the ink receiving layer, suppresses cracks and cracks, etc., suppresses the wind ripples that tend to occur during drying, and the ink pigment particles applied to the ink receiving layer It also prevents the aggregation of the.

  As the smoothing agent, a monovalent or divalent inorganic acid or a readily water-soluble inorganic salt thereof can be used. However, it is possible to increase the image density of the pigment ink by preventing excessive aggregation of the pigment in the ink. , Hydrochloric acid, sulfuric acid, amidosulfuric acid or a salt thereof, and sulfate or amidosulfate is particularly preferable.

The reason why the gel by the smoothing agent of the present invention has heat resistance is not clear, but the crosslinking treatment and drying treatment (both of the ink receiving layer coating liquid) are caused by some interaction of the smoothing agent, the inorganic fine particles and the ultraviolet crosslinking resin. The inorganic fine particles are held (preset) in a state of being stably dispersed in the matrix of the resin component even during processing and volume reduction due to a change in the conformation or configuration of the resin used). This is probably because the particles are dried and gel (fixed) almost as they are, so that the aggregation of the inorganic fine particles is prevented and the water retention is improved, and the dispersed state of the inorganic fine particles immediately after coating can be maintained.
On the other hand, inorganic aluminum-containing cationic polymers, such as basic polyaluminum hydroxide compounds, have inorganic fine particles stably dispersed in the resin component matrix during the crosslinking and drying treatments of the ink-receiving layer coating solution. When the basic polyaluminum hydroxide compound is used, it is preferably used in combination with monovalent or divalent hydrochloride, sulfate, amidosulfuric acid or an inorganic salt thereof.

  Among the readily water-soluble inorganic salts, the hydrochloride includes, for example, sodium chloride, ammonium chloride, magnesium chloride, potassium chloride, calcium chloride, zinc chloride, copper chloride, barium chloride, and the like, elements or atoms that are more positive than chlorine. The compound which forms with a group is mentioned, When a smoothing agent is hydrochloride, it is preferable that it is a monovalent metal salt.

  Examples of the sulfate include compounds formed with elements or element groups in which sulfate ions are more positive, such as sodium sulfate, ammonium sulfate, magnesium sulfate, potassium sulfate, calcium sulfate, zinc sulfate, copper sulfate, and barium sulfate. It is done.

  Examples of the amide sulfate include compounds that form sulfamic acid ions with elements or atomic groups that are more positive, such as sodium amide sulfate, ammonium amide sulfate, magnesium bis (amidosulfate), and nickel amide sulfate tetrahydrate. Can be mentioned.

  The leveling agent is preferably contained in the ink-receiving layer in an amount of 0.3 wt% to 7 wt%, preferably 0.5 wt% to 5 wt%, depending on the type and the type and amount of the inorganic pigment and the crosslinkable resin component. % Or less is more preferable. If the content of the smoothing agent is less than 0.3 wt%, it is often impossible to sufficiently preset the inorganic pigment in a state of being uniformly dispersed in the ink receiving layer coating solution, and the ink receiving layer is crosslinked, dried, and gel (fixed). ), The voids between the inorganic pigment particles are crushed and the ink absorbability is lowered. Also, the surface of the ink receiving layer is depressed, cracks and cracks are generated, and the gloss and ink absorbability are decreased. If it exceeds 7 wt%, uneven coating tends to occur.

<UV cross-linked resin>
As the ultraviolet crosslinking resin component, a resin that is crosslinked by ultraviolet irradiation can be used, and a resin having a hydrophilic resin having a hydrophilic group as a main chain and a plurality of photoreactive groups in a side chain can be preferably used.
For example, a water-soluble polymer having two or more ethylenic double bonds in one molecule, and unsaturated polyester, modified unsaturated polyester, acrylic polymer, methacrylic polymer having a functional group at the terminal or side chain. Well-known water-soluble polymers, such as a polymer, a polymer having a vinyl type unsaturated bond, and an epoxy compound, may be mentioned.

The UV-crosslinked resin can be obtained by allowing a side chain modifying group such as a photodimerization type, a photodecomposition type, a photodepolymerization type, a photomodification type, or a photopolymerization type to act on a hydrophilic resin. A cross-linked group-modified polymer having a photopolymerizable type modifying group is preferred, and a cross-linked group-modified polymer having a photopolymerizable type modifying group is more preferred.
For the purpose of adjusting the crosslinkability, an oligomer or monomer having a monofunctional or polyfunctional ethylenic double bond may be used in combination.

  Examples of the hydrophilic resin include polyalkylene oxides such as polyvinyl alcohol and polyethylene oxide, polyvinyl pyrrolidone, water-soluble polyvinyl acetal, poly-N-vinylacetamide, polyacrylamide, polyacryloylmorpholine, polyhydroxyacryl acrylate, polyacrylic acid, hydroxy Examples thereof include ethyl cellulose, methyl cellulose, hydroxypropyl cellulose, gelatin, casein, and water-soluble derivatives and copolymers thereof, and polyvinyl alcohol is preferable.

  Examples of the side chain modifying group include a vinyl group, acryloyl group, methacryloyl group, cinnamoyl group, stilbazonium group, stilquinolium group, diazo group, alicyclic epoxy group, acetoacetyl group, etc. An acetyl group and an acryloyl group are preferred because they can prevent cracks and cracks with a small amount of ultraviolet irradiation.

  Specifically, examples of the photopolymerizable ultraviolet crosslinking resin include a resin represented by the following general formula (1) described in JP-A No. 2000-181062, and a polymer having an acetoacetyl group in the side chain. A polymer having an acetoacetyl group can be preferably used because it can prevent cracking with a small amount of ultraviolet irradiation and has little yellowing of the background.

In the general formula (1), R ₂ represents a hydrogen atom or a methyl group, and Y represents an aromatic ring or a single bond. n represents 1 or 2.

  The polymer having an acetoacetyl group in the present invention can be synthesized by a method of copolymerizing a monomer having an acetoacetyl group with another monomer.

Specific examples of the monomer having an acetoacetyl group include acetoacetoxyethyl methacrylate, 4-vinylacetoacetanilide, acetoacetylallylamide, and the like. Moreover, you may introduce | transduce an acetoacetyl group by polymer reaction, for example, an acetoacetyl group can be introduce | transduced by reaction etc. of a hydroxy group and diketene.
Specific examples of the resin polymer having an acetoacetyl group include acetoacetyl-modified polyvinyl alcohol, acetoacetyl-modified cellulose derivatives, and acetoacetyl-modified starch. In the present invention, modified polyvinyl alcohol having an acetoacetyl group is particularly preferable.

  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. The degree of polymerization is preferably from 500 to 5000, and particularly preferably from 1500 to 4500.

Examples of the photodimerization type ultraviolet crosslinking resin include a photosensitive resin in which a stilbazonium group is introduced into a polyvinyl alcohol structure represented by the following general formula (2) described in JP-A-60-129742.

In the general formula (2), R ₁ represents an alkyl group having 1 to 4 carbon atoms, and A ⁻ represents an anionic group.

  In the present invention, in addition to the ultraviolet crosslinking resin, other known polymers can be used in combination. Examples of the resin that can be used in combination with the ultraviolet crosslinking resin include 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, and various modified polyvinyls. Alcohol, polyvinyl pyrrolidone, polyacrylamide and the like can be used together as necessary, and various latexes can be used in combination.

A photoreaction initiator, a sensitizer, a polymerization inhibitor, and the like can be blended with the UV-crosslinked resin of the present invention as necessary.
As the photoinitiator, a known water-soluble material can be used, and the amount of this is not particularly limited. For example, it is used in the range of 0.1 to 5% by weight with respect to the above-mentioned water-soluble polymer. Can do.
Moreover, as a sensitizer, a well-known water-soluble material can be used, and a compounding quantity will not be specifically limited if determined according to the kind and bridge | crosslinking conditions requested | required of this composition, For example, 0.005 The range of 10 to 10% by weight can be used.

  The content of the ultraviolet crosslinking resin in the ink receiving layer is preferably in the range of 5 to 40% by mass, particularly preferably in the range of 10 to 30% by mass with respect to the inorganic fine particles.

<Inorganic fine particles>
The inorganic fine particles used in the ink receiving layer of the present invention are retained in a state of being stably dispersed in the matrix of the resin component during the crosslinking treatment and drying treatment of the inkjet coating liquid due to the presence of a smoothing agent. And can be used as long as it is dried and gelled (fixed) almost as it is, for example, known colorless or amorphous silica, alumina, alumina hydrate, titanium dioxide, etc. White metal oxide fine particles, calcium carbonate, and magnesium carbonate can be used. An extender composed of a white or colorless inorganic pigment is preferable, and therefore, not only inorganic fine particles but also, for example, ultrafine resin can be used in combination.
Amorphous synthetic silica, alumina, or alumina hydrate is preferable from the viewpoint of ink absorbability and productivity.

  The amorphous synthetic silica can be roughly classified into gas phase method silica, wet method silica, and others depending on the production method, and gas phase method silica can be preferably used from the viewpoint of ink absorbability.

The gas phase method 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.

The wet method silica is further classified into precipitation method silica, gel method silica, and sol method silica according to the production method. Precipitated silica is produced by reacting sodium silicate and sulfuric acid under alkaline conditions, and the silica particles that have grown are agglomerated and settled, and are then commercialized through the steps of filtration, washing, drying, pulverization and classification.
Precipitated silica is commercially available, for example, from Tosoh Silica Co., Ltd. as a nip seal and from Tokuyama Co., Ltd. as a Toxeal.

Gel silica is produced by reacting sodium silicate and sulfuric acid under acidic conditions. During 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 as nip gel from Tosoh Silica Co., Ltd., and as syloid and silo jet from Grace Japan Co., Ltd.

The sol method silica is also called colloidal silica, 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.

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.

Wet method As a specific method for finely pulverizing silica fine particles, silica particles and a cationic compound are mixed in water (either may be added first or at the same time), or each dispersion or aqueous solution is mixed. And a preliminary dispersion is obtained using at least one of a dispersing device such as a serrated blade type disperser, a propeller blade type disperser, or a rotor stator type disperser. If necessary, an appropriate low boiling point solvent may be added.

The wet dispersion silica pre-dispersion preferably has a higher solid content, but if the concentration is too high, it becomes impossible to disperse, so the preferred range is 15 to 40% by weight, more preferably 20 to 35% by weight. .

Next, by applying a stronger mechanical means, a wet process silica fine particle dispersion having an average secondary particle diameter of 500 nm or less is obtained. As a mechanical means, a known method can be adopted, for example, a media mill such as a ball mill, a bead mill, a sand grinder, a high pressure homogenizer, a pressure disperser such as an ultra high pressure homogenizer, an ultrasonic disperser, a thin film swirl disperser, etc. Can be used.

As the alumina, γ-alumina, which is a γ-type crystal of aluminum oxide, is preferable, and among them, a δ group crystal is preferably used.
γ-alumina can make primary particles as small as about 10 nm. Usually, secondary particle crystals of several thousand to several tens of thousands nm are pulverized with ultrasonic waves, a high-pressure homogenizer, a counter-impact type jet pulverizer, or the like. Can be used.

The alumina hydrate is represented by a constitutive formula of Al ₂ O ₃ .nH ₂ O (n = 1 to 3). The case where n is 1 represents an alumina hydrate having a boehmite structure, and the case where n is greater than 1 and less than 3 represents an alumina hydrate having a pseudo boehmite structure.
The alumina hydrate 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 primary particle diameter of the inorganic fine particles in the present invention is preferably 30 nm or less, and in order to obtain higher gloss, it is preferably 15 nm or less, more preferably 3 to 15 nm, and particularly preferably 3 to 10 nm.

Further, the specific surface area of the inorganic fine particles by the BET method is preferably 200 m ² / g or more, and more preferably 250 to 500 m ² / g.

The average primary particle diameter as used in the present invention refers to the average particle diameter obtained by observing fine particles with an electron microscope and taking the diameter of a circle equal to the projected area of each of 100 primary particles present within a certain area as the particle diameter of the particles. 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. is there. Usually, nitrogen gas is often used as the adsorbed gas, and the most frequently used method is to measure the amount of adsorption from the change in pressure or volume of the gas to be adsorbed. The most prominent expression for expressing the isotherm of multimolecular adsorption is the Brunauer, Emmett, and Teller equation, called the BET equation, which is widely used for determining the surface area. The adsorption amount is obtained based on the BET equation, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

The average secondary particle diameter of the inorganic fine particles is preferably 500 nm or less, more preferably 10 to 300 nm, and even more preferably 20 to 200 nm.
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.

Next, the dispersant for the dispersion of inorganic fine particles will be described.
As the dispersant for the vapor phase silica and the wet method silica, a cationic compound can be used, and a cationic polymer or a water-soluble metal compound can be used.
However, a water-soluble metal compound needs to be noted because it may agglomerate ink pigment particles and lower the image density.

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, 60-11389, 60-49990, 60-83882, 60-109894, 62-198493, 63-49478, 63-115780, No. 63-280681, No. 1-40371, No. 6-234268, No. 7-125411, No. 10-193976, etc. In particular, a diallylamine derivative is 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. Among these, a compound made of aluminum or a group 4A metal (for example, zirconium or titanium) of 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 is a water treatment agent 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 ( It is marketed by RIKEN GREEN under the name of Purachem WT, and other manufacturers with 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, basic zirconium carbonate, zirconium hydroxide, zirconium lactate, zirconium carbonate / ammonium, zirconium carbonate / potassium, zirconium sulfate, fluoride. A zirconium compound etc. are mentioned. 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 dispersant for alumina and alumina hydrate, known dispersants such as acetic acid, lactic acid and formic acid can be used.

As the dispersion method of the inorganic fine particles, 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 It is preferable to perform dispersion using a pressure disperser such as a homogenizer or an ultrahigh pressure homogenizer, an ultrasonic disperser, a thin film swirl disperser, or the like.

The ratio of the inorganic fine particles to the total solid content of the ink receiving layer is preferably 50% by mass or more, more preferably 60% by mass or more, and further preferably in the range of 65 to 95% by mass.

<Crosslinking agent>
In the ink receiving layer of the present invention, a known cross-linking agent may be added to the ink receiving layer as necessary, as long as the effect of the present invention is not impaired or the viscosity of the coating solution does not increase with time. Also good.

When modified polyvinyl alcohol is used as the resin binder, the polyvinyl alcohol crosslinking agent includes aldehyde compounds such as formaldehyde and glutaraldehyde, ketone compounds such as diacetyl and chloropentanedione, bis (2-chloroethylurea), 2- Hydroxy-4,6-dichloro-1,3,5-triazine, a compound having a reactive halogen as described in US Pat. No. 3,288,775, divinyl sulfone, as described in US Pat. No. 3,635,718 Compounds having reactive olefins, 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 aziridine compounds described in U.S. Pat. No. 2,983,611 Carbodiimide compounds as described in US Pat. No. 3,100,704, epoxy compounds as described in US Pat. No. 3,091,537, halogen carboxaldehydes such as mucochloric acid, dioxane derivatives such as dihydroxydioxane, Inorganic cross-linking agents such as slag, zirconium sulfate, boric acid, borates and borax can be used.

<Support>
As the support used in the present invention, either a water-absorbing support or a non-water-absorbing support can be used, but the water absorption is low in order to obtain a glossy surface and a high image density as required for photographic images. It is preferable.

As the water-absorbing support, fine paper, art paper, coated paper, cast coated paper, and the like can be used, but coated paper having low water absorption is preferable.

Examples of the non-water-absorbing support include water-resistant supports such as polyethylene, polypropylene, polyvinyl chloride, diacetate resin, triacetate resin, cellophane, acrylic resin, polyethylene terephthalate, polyethylene naphthalate, and polyolefin resin-coated paper. Can be mentioned.

  The support in the present invention can be provided with various backcoat layers applied for writing properties, antistatic properties, transport properties, anticurling properties and the like. In the backcoat layer, an inorganic antistatic agent, an organic antistatic agent, a hydrophilic binder, latex, a pigment, a crosslinking agent, a surfactant, and the like can be contained in appropriate combinations.

Next, a method for forming the ink receiving layer will be described.
In the ink receiving layer of the present invention, an ink receiving layer coating liquid containing an ultraviolet crosslinking resin, an inorganic pigment, and a smoothing agent is applied onto a support, and the coating liquid is dried before the ink receiving layer coating liquid is dried at a reduced rate. It can be formed by irradiating with UV and drying.

The timing of ultraviolet irradiation must be performed prior to the end of drying to prevent cracks associated with drying. Specifically, this is before the fluidity of the applied ink-receiving layer is lost, which generally coincides before the reduced rate drying begins. Further, it may be before the start of drying.

The integrated irradiation dose of ultraviolet, radiation spectrum, depending on the polymer type or the like is ^{preferably 10mJ / cm 2 ~900mJ / cm 2} .
If it is less than 10 mJ / cm ² , the smoothness of the surface may decrease, and if it exceeds 900 mJ / cm ² , the strength of the ink receiving layer may decrease.

In the present invention, since the ink receiving layer coating liquid is gelled by the smoothing agent and the inorganic fine particles exist stably, it is not necessary to form a strong cross-linked structure by irradiating strong ultraviolet rays, and gently with a small amount of ultraviolet rays. By polymerizing, coupled with the reduction of intermolecular strain and volume shrinkage that occur during the formation of a crosslinked structure, the voids between the inorganic fine particles are not collapsed, and a smooth and highly ink-absorbing ink-receiving layer is formed. In addition to reducing the environmental load (increase in CO ₂ emissions) and manufacturing costs during manufacturing, it is possible to prevent deterioration of the support.

As the ultraviolet irradiation light source used in the present invention, an ultraviolet lamp such as a low-pressure mercury lamp, a high-pressure mercury lamp, or a metal halide lamp can be preferably used.

The drying temperature is preferably 100 ° C to 250 ° C. If the temperature is lower than 100 ° C., drying takes time and the production efficiency is lowered, and if it exceeds 250 ° C., curling or the like may occur.
As the drying device, a conventionally known drying device such as a hot air coater can be used.

The dry coating amount of the ink receiving layer according to the present invention is in the range of 8 to 40 g / m ² , particularly 10 to 30 g 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 addition, the ink jet recording material of the present invention may be prepared by applying a corona discharge treatment, a flame treatment, an ultraviolet irradiation treatment, a plasma treatment, or the like prior to the application of the ink receiving layer coating liquid, It is preferable to provide an undercoat layer mainly composed of a synthetic resin.

The application of other functional layers such as the ink receiving layer and the undercoat layer can be performed by a known application method, such as a slide bead method, a curtain method, an extrusion method, an air knife method, a roll coating method, or a rod bar coating. It can apply | coat by a system etc.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to the following Example.
In addition, when there is no description in particular, a part and% show a mass part and the mass%. The mol% is the ratio of vinyl alcohol units.

A method for evaluating the ink jet recording material will be described.
<Crack>
With respect to 10 cm ² of the ink receiving layer coating surface of the ink jet recording material, the number of crack failures was measured using a magnifying glass (magnification: 100 times), and the coating failure resistance was evaluated according to the following criteria.

◎: No occurrence of crack failure is observed. ○: 1 to 3 crack failures occur. △: 4 to 10 crack failures occur. ×: 11 or more crack failures occur. ing

If it is higher than the rank, it is practically acceptable.

<Pigment ink image density>
A Bk solid image was printed in the photo gloss mode of a pigment inkjet printer PX-G930 manufactured by EPSON, and the Bk image density was measured with Spectrolino manufactured by Gretag Macbeth.

[Example 1]
<Preparation of support A>
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 100 parts of low-density polyethylene having a density of 0.918 g / cm ³ , and the thickness is made 35 μm. Extrusion-coating was performed, 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 an undercoat layer having the following composition was applied and dried so that the gelatin content was 50 mg / m ² (about 0.05 μm) to prepare a support A.

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

<Preparation of inorganic fine particle dispersion A>
4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight 9,000) and 100 parts of vapor phase process silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g, Aerosil 300 manufactured by Nippon Aerosil Co., Ltd.) are added to water. After the production, an inorganic fine particle dispersion A having a solid content concentration of 20% was produced by treatment with a high-pressure homogenizer. The average secondary particle size after dispersion was 500 nm.

<Ink-receiving layer coating solution 1>
Inorganic fine particle dispersion A (as inorganic fine particle solid content) 100 parts Resin A 22 parts (acetoacetyl-modified polyvinyl alcohol: polymerization degree 2350, modification degree 3 mol%, saponification degree 98 mol%)
Hydrochloric acid 3 parts Nonionic surfactant (polyoxyethylene alkyl ether) 0.3 part The solid content concentration was adjusted to 10% by mass with water.

(Synthesis of resins A and D to G)
With reference to the method described in JP-B-63-52672, polyvinyl alcohol obtained by partially saponifying polyvinyl acetate is dispersed in an acetic acid solvent, and diketene is added to react the diketene to give resins A, D to G was obtained.
The degree of polymerization, the degree of saponification, and the degree of modification were adjusted according to the degree of polymerization, degree of saponification, and amount of diketene added. The mol% of the degree of modification was a value per vinyl alcohol unit.

<Preparation of inkjet recording material>
The support A was coated with a wire bar so that the dry solid content of the inkjet receptive layer coating solution 1 was 20 g / m ² , and firstly with a high-pressure mercury lamp, UV integrated illuminance meter PD-365 (manufactured by Eye Graphics) The inkjet recording material 1 was obtained by irradiating with an ultraviolet ray amount such that the measured integrated irradiation amount was 500 mJ / cm ² and then spraying and drying air at 120 ° C.

[Example 2]
An ink jet recording material 2 was obtained in the same manner as in Example 1 except that the hydrochloric acid used in the ink receiving layer coating liquid 1 of Example 1 was changed to sodium chloride.

[Example 3]
An inkjet recording material 3 was obtained in the same manner as in Example 1 except that the hydrochloric acid used in the ink receiving layer coating solution 1 of Example 1 was changed to ammonium chloride.

[Example 4]
An ink jet recording material 4 was obtained in the same manner as in Example 1 except that the hydrochloric acid in the ink receiving layer coating liquid 1 of Example 1 was changed to potassium chloride.

[Example 5]
An ink jet recording material 5 was obtained in the same manner as in Example 1 except that the hydrochloric acid in the ink receiving layer coating solution 1 of Example 1 was changed to magnesium chloride.

[Example 6]
An ink jet recording material 6 was obtained in the same manner as in Example 1 except that the hydrochloric acid in the ink receiving layer coating solution 1 of Example 1 was changed to calcium chloride.

[Example 7]
An ink jet recording material 7 was obtained in the same manner as in Example 1, except that the hydrochloric acid in the ink receiving layer coating solution 1 of Example 1 was changed to sulfuric acid.

[Example 8]
An ink jet recording material 8 was obtained in the same manner as in Example 1 except that the hydrochloric acid in the ink receiving layer coating solution 1 of Example 1 was changed to sodium sulfate.

[Example 9]
An ink jet recording material 9 was obtained in the same manner as in Example 1 except that the hydrochloric acid in the ink receiving layer coating solution 1 of Example 1 was changed to ammonium sulfate.

[Example 10]
An inkjet recording material 10 was obtained in the same manner as in Example 1 except that the hydrochloric acid in the ink-receiving layer coating solution 1 of Example 1 was changed to magnesium sulfate.

[Example 11]
An ink jet recording material 11 was obtained in the same manner as in Example 1 except that the hydrochloric acid in the ink receiving layer coating solution 1 of Example 1 was changed to calcium sulfate dihydrate.

[Example 12]
An inkjet recording material 12 was obtained in the same manner as in Example 1 except that the hydrochloric acid in the ink-receiving layer coating solution 1 of Example 1 was changed to amidosulfuric acid.

[Example 13]
An ink jet recording material 13 was obtained in the same manner as in Example 1, except that the hydrochloric acid in the ink receiving layer coating solution 1 of Example 1 was changed to sodium amide sulfate.

[Example 14]
An ink jet recording material 14 was obtained in the same manner as in Example 1 except that the hydrochloric acid in the ink receiving layer coating liquid 1 of Example 1 was changed to magnesium amidosulfate.

[Example 15]
Inkjet recording material 15 was prepared in the same manner as in Example 2 except that the support A in Example 2 was changed to the support B (coated paper: Nippon Paper Industries, Aurora Coat, basis weight 127.9 g / m ² ). Got.

[Example 16]
Inkjet recording material 16 was prepared in the same manner as in Example 5 except that the support A in Example 5 was changed to the support B (coated paper: manufactured by Nippon Paper Industries Co., Ltd., Aurora Coat, basis weight 127.9 g / m ² ). Got.

[Example 17]
Inkjet recording material 17 was prepared in the same manner as in Example 8, except that the support A in Example 8 was changed to the support B (coated paper: manufactured by Nippon Paper Industries Co., Ltd., Aurora Coat, basis weight 127.9 g / m ² ). Got.

[Example 18]
Inkjet recording material 18 in the same manner as in Example 10 except that the support A in Example 10 was changed to the support B (coated paper: Nippon Paper Industries, Aurora Coat, basis weight 127.9 g / m ² ). Got.

[Example 19]
Inkjet recording material 19 was carried out in the same manner as in Example 13 except that the support A in Example 13 was changed to the support B (coated paper: manufactured by Nippon Paper Industries Co., Ltd., Aurora Coat, basis weight 127.9 g / m ² ). Got.

[Example 20]
Inkjet recording material 20 in the same manner as in Example 14 except that the support A in Example 14 was changed to the support B (coated paper: Nippon Paper Industries, Aurora Coat, basis weight 127.9 g / m ² ). Got.

[Example 21]
An inkjet recording material 21 was obtained in the same manner as in Example 2, except that the support A in Example 2 was changed to the support C (quality paper, basis weight 64 g / m ² ).

[Example 22]
An inkjet recording material 22 was obtained in the same manner as in Example 5 except that the support A in Example 5 was changed to the support C (quality paper, basis weight 64 g / m ² ).

[Example 23]
An inkjet recording material 23 was obtained in the same manner as in Example 8, except that the support A in Example 8 was changed to the support C (quality paper, basis weight 64 g / m ² ).

[Example 24]
An inkjet recording material 24 was obtained in the same manner as in Example 10, except that the support A in Example 10 was changed to the support C (quality paper, basis weight 64 g / m ² ).

[Example 25]
An ink jet recording material 25 was obtained in the same manner as in Example 13 except that the support A in Example 13 was changed to the support C (quality paper, basis weight 64 g / m ² ).

[Example 26]
An inkjet recording material 26 was obtained in the same manner as in Example 14, except that the support A in Example 14 was changed to the support C (quality paper, basis weight 64 g / m ² ).

The above-described evaluation was performed on the inkjet recording materials 1 to 26. The evaluation results are shown in Table 1.

In Examples 1 to 12, it was found that an ink jet recording material having a high pigment ink image density was obtained in addition to a uniform coating surface with no cracks in the layer.
From Examples 1 to 14 and Examples 15 to 26, there is an effect of the present invention regardless of the type of support.
However, since the support C (quality paper) has higher water absorption than other supports, the resin, which is a water-soluble material of the ink jet receiving layer, is likely to permeate, and the ink jet receiving layer is likely to crack. ing.
In Examples 1 to 4 and Examples 7 to 14, since the pigment ink image density is high, monovalent hydrochloric acid or hydrochloride, monovalent or divalent sulfuric acid and sulfate, and monovalent or divalent amide It can be seen that sulfuric acid and amidosulfates are preferred.

[Example 27]
An ink jet recording material 27 was obtained in the same manner as in Example 2 except that the inorganic fine particle dispersion A of Example 2 was changed to the following inorganic fine particle dispersion B.

<Inorganic fine particle dispersion B>
4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight 9,000) and 100 parts of vapor-phase process silica (average primary particle size 12 nm, specific surface area 200 m ² / g, Aerosil 200 manufactured by Nippon Aerosil Co., Ltd.) are added to water. After the production, an inorganic fine particle dispersion B having a solid content of 20% was produced by treatment with a high-pressure homogenizer. The average secondary particle size after dispersion was 500 nm.

[Example 28]
An ink jet recording material 28 was obtained in the same manner as in Example 5 except that the inorganic fine particle dispersion A of Example 5 was changed to the inorganic fine particle dispersion B.

[Example 29]
An ink jet recording material 29 was obtained in the same manner as in Example 8, except that the inorganic fine particle dispersion A in Example 8 was changed to the inorganic fine particle dispersion B.

[Example 30]
An ink jet recording material 30 was obtained in the same manner as in Example 10 except that the inorganic fine particle dispersion A in Example 10 was changed to the inorganic fine particle dispersion B.

[Example 31]
An inkjet recording material 31 was obtained in the same manner as in Example 13 except that the inorganic fine particle dispersion A in Example 13 was changed to the inorganic fine particle dispersion B.

[Example 32]
An inkjet recording material 32 was obtained in the same manner as in Example 14 except that the inorganic fine particle dispersion A in Example 14 was changed to the inorganic fine particle dispersion B.

[Example 33]
An inkjet recording material 33 was obtained in the same manner as in Example 2 except that the inorganic fine particle dispersion A of Example 2 was changed to the following inorganic fine particle dispersion C.

<Inorganic fine particle dispersion C>
After adding 4 parts of basic polyaluminum hydroxide and 100 parts of vapor phase process silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g, Aerosil 300 manufactured by Nippon Aerosil) to water, a preliminary dispersion was prepared, and then a high-pressure homogenizer To prepare an inorganic fine particle dispersion C having a solid concentration of 20%. The average secondary particle size after dispersion was 500 nm.

[Example 34]
An ink jet recording material 34 was obtained in the same manner as in Example 5 except that the inorganic fine particle dispersion A in Example 5 was changed to the inorganic fine particle dispersion C.

[Example 35]
An ink jet recording material 35 was obtained in the same manner as in Example 8, except that the inorganic fine particle dispersion A in Example 8 was changed to the inorganic fine particle dispersion C.

[Example 36]
An ink jet recording material 36 was obtained in the same manner as in Example 10 except that the inorganic fine particle dispersion A in Example 10 was changed to the inorganic fine particle dispersion C.

[Example 37]
An ink jet recording material 37 was obtained in the same manner as in Example 13 except that the inorganic fine particle dispersion A in Example 13 was changed to the inorganic fine particle dispersion C.

[Example 38]
An ink jet recording material 38 was obtained in the same manner as in Example 14 except that the inorganic fine particle dispersion A in Example 14 was changed to the inorganic fine particle dispersion C.

[Example 39]
An ink jet recording material 39 was obtained in the same manner as in Example 2 except that the inorganic fine particle dispersion A of Example 2 was changed to the following inorganic fine particle dispersion D.

<Inorganic fine particle dispersion D>
Add 4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight 9,000) and 100 parts of wet silica (Tosoh silica: Nipseal LP, primary particle diameter 16 nm, specific surface area 170 m ² / g) to water, pulverize with a bead mill, and then high pressure By processing with a homogenizer, an inorganic fine particle dispersion D having a solid content concentration of 20% was produced. The average secondary particle size after dispersion was 500 nm.

[Example 40]
An ink jet recording material 40 was obtained in the same manner as in Example 5 except that the inorganic fine particle dispersion A in Example 5 was changed to the inorganic fine particle dispersion D.

[Example 41]
An inkjet recording material 41 was obtained in the same manner as in Example 8 except that the inorganic fine particle dispersion A in Example 8 was changed to the inorganic fine particle dispersion D.

[Example 42]
An ink jet recording material 42 was obtained in the same manner as in Example 10, except that the inorganic fine particle dispersion A in Example 10 was changed to the inorganic fine particle dispersion D.

[Example 43]
An ink jet recording material 43 was obtained in the same manner as in Example 13 except that the inorganic fine particle dispersion A in Example 13 was changed to the inorganic fine particle dispersion D.

[Example 44]
An ink jet recording material 44 was obtained in the same manner as in Example 14 except that the inorganic fine particle dispersion A of Example 14 was changed to the inorganic fine particle dispersion D.

[Example 45]
An inkjet recording material 45 was obtained in the same manner as in Example 1 except that the inorganic fine particle dispersion A in Example 1 was changed to the following inorganic fine particle dispersion E.

<Inorganic fine particle dispersion E>
The inorganic fine particle dispersion E was an alumina sol (BET specific surface area 300 m ² / g, average secondary particle size 200 nm, alumina sol 200 manufactured by Nissan Chemical Industries, Ltd.) having a solid content concentration of 10%.

[Example 46]
An inkjet recording material 46 was obtained in the same manner as in Example 2 except that the inorganic fine particle dispersion A in Example 2 was changed to the inorganic fine particle dispersion E.

[Example 47]
An ink jet recording material 47 was obtained in the same manner as in Example 7 except that the inorganic fine particle dispersion A in Example 7 was changed to the inorganic fine particle dispersion E.

[Example 48]
An inkjet recording material 48 was obtained in the same manner as in Example 8, except that the inorganic fine particle dispersion A in Example 8 was changed to the inorganic fine particle dispersion E.

[Example 49]
An inkjet recording material 49 was obtained in the same manner as in Example 12 except that the inorganic fine particle dispersion A in Example 12 was changed to the inorganic fine particle dispersion E.

[Example 50]
An inkjet recording material 50 was obtained in the same manner as in Example 13, except that the inorganic fine particle dispersion A in Example 13 was changed to the inorganic fine particle dispersion E.

The above-described evaluation was performed on the inkjet recording materials 27 to 50. The evaluation results are shown in Table 2.

From Examples 1 to 14 and Examples 33 to 50, it can be seen that the effect of the present invention is obtained regardless of the type of inorganic fine particle dispersion and the dispersant for inorganic fine particles.

[Example 51]
Resin A of Example 2 was changed to the following resin B (acryloyl group-modified polyvinyl alcohol: degree of polymerization 3500, degree of modification 3 mol%, saponification degree 88 mol%, initiator: acylphosphine oxide aqueous dispersion 0.5 to resin The inkjet recording material 51 was obtained in the same manner as in Example 2 except that the weight was changed to (% by weight).

(Synthesis of Resin B)
With reference to the method described in JP-A-2000-181062, 45 g of polyvinyl alcohol (PVA-235 manufactured by Kuraray Co., Ltd., polymerization degree 3500 saponification degree 88%) obtained by partially saponifying polyvinyl acetate at 80 ° C. After dissolving in hot water, adding 15 g of the compound represented by the following formula (3) in the presence of 4.5 g of an acid catalyst (phosphoric acid), reacting at 80 ° C. for 6 hours to acetalize, then basic ions Resin B was prepared by removing the acid catalyst with an exchange resin.

[Example 52]
An ink jet recording material 52 was obtained in the same manner as in Example 5 except that the resin A in Example 5 was changed to the resin B.

[Example 53]
An ink jet recording material 53 was obtained in the same manner as in Example 8 except that the resin A in Example 8 was changed to the resin B.

[Example 54]
An ink jet recording material 54 was obtained in the same manner as in Example 10 except that the resin A in Example 10 was changed to the resin B.

[Example 55]
An ink jet recording material 55 was obtained in the same manner as in Example 13 except that the resin A in Example 13 was changed to the resin B.

[Example 56]
An ink jet recording material 56 was obtained in the same manner as in Example 14 except that the resin A in Example 14 was changed to the resin B.

[Example 57]
An inkjet recording material 57 was prepared in the same manner as in Example 2 except that the resin A of Example 2 was changed to the following resin C (stilbazonium group-modified polyvinyl alcohol: degree of polymerization 3500, degree of modification 2 mol%, saponification degree 88 mol%). Obtained.

(Synthesis of Resin C)
With reference to the method described in JP-A-60-129742, 45 g of polyvinyl alcohol (PVA-235 manufactured by Kuraray Co., Ltd., polymerization degree 3500, saponification degree 88%) obtained by partially saponifying polyvinyl acetate, After reacting 4.5 g of a stilbazonium salt having a formyl group represented by the following formula (4) in the presence of 10 g of an acid catalyst (phosphoric acid) at 80 ° C. for 6 hours, the acid catalyst was removed with a basic ion exchange resin. Resin C was synthesized.

[Example 58]
An ink jet recording material 58 was obtained in the same manner as in Example 5 except that the resin A in Example 5 was changed to the resin C.

[Example 59]
An inkjet recording material 59 was obtained in the same manner as in Example 8 except that the resin A in Example 8 was changed to the resin C.

[Example 60]
An ink jet recording material 60 was obtained in the same manner as in Example 10 except that the resin A in Example 10 was changed to the resin C.

[Example 61]
An ink jet recording material 61 was obtained in the same manner as in Example 13 except that the resin A in Example 13 was changed to the resin C.

[Example 62]
An inkjet recording material 62 was obtained in the same manner as in Example 14 except that the resin A in Example 14 was changed to the resin C.

[Example 63]
Inkjet recording material 63 in the same manner as in Example 8, except that the resin A in Example 8 was changed to Resin D (acetoacetyl-modified polyvinyl alcohol: polymerization degree 1500, modification degree 3 mol%, saponification degree 98 mol%). Got.

[Example 64]
Inkjet recording material 64 in the same manner as in Example 8, except that Resin A in Example 8 was changed to Resin E (acetoacetyl-modified polyvinyl alcohol: degree of polymerization 2350, degree of modification 1 mol%, degree of saponification 98 mol%). Got.

[Example 65]
Inkjet recording material 65 in the same manner as in Example 8, except that Resin A in Example 8 was changed to Resin F (acetoacetyl-modified polyvinyl alcohol: polymerization degree 2600, modification degree 4 mol%, saponification degree 92 mol%). Got.

[Example 66]
Inkjet recording material 66 in the same manner as in Example 8, except that Resin A in Example 8 was changed to Resin G (acetoacetyl-modified polyvinyl alcohol: degree of polymerization 3500, degree of modification 2 mol%, degree of saponification 88 mol%). Got.

The above-described evaluation was performed on the inkjet recording materials 51 to 66. The evaluation results are shown in Table 3.

From Examples 1 to 14 and Examples 51 to 66, the type of the ultraviolet crosslinking resin is not selected, and the effects of the present invention are obtained.

[Example 67]
An ink jet recording material 67 was obtained in the same manner as in Example 2 except that the inorganic fine particle dispersion A in Example 2 was changed to the inorganic fine particle dispersion F.
<Inorganic fine particle dispersion F>
4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight 9,000) and 100 parts of vapor phase process silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g, Aerosil 300 manufactured by Nippon Aerosil Co., Ltd.) are added to water. After the production, an inorganic fine particle dispersion A having a solid content concentration of 20% was produced by treatment with a high-pressure homogenizer. The average secondary particle size after dispersion was 200 nm.

[Example 68]
An ink jet recording material 68 was obtained in the same manner as in Example 5 except that the inorganic fine particle dispersion A in Example 5 was changed to the inorganic fine particle dispersion F.

[Example 69]
An ink jet recording material 69 was obtained in the same manner as in Example 8, except that the inorganic fine particle dispersion A in Example 8 was changed to the inorganic fine particle dispersion F.

[Example 70]
An inkjet recording material 70 was obtained in the same manner as in Example 10 except that the inorganic fine particle dispersion A in Example 10 was changed to the inorganic fine particle dispersion F.

[Example 71]
An ink jet recording material 71 was obtained in the same manner as in Example 13 except that the inorganic fine particle dispersion A in Example 13 was changed to the inorganic fine particle dispersion F.

[Example 72]
An ink jet recording material 72 was obtained in the same manner as in Example 14 except that the inorganic fine particle dispersion A in Example 14 was changed to the inorganic fine particle dispersion F.

[Example 73]
An ink jet recording material 73 was obtained in the same manner as in Example 2 except that the inorganic fine particle dispersion A in Example 2 was changed to the inorganic fine particle dispersion G.

<Inorganic fine particle dispersion G>
4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight 9,000) and 100 parts of vapor phase process silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g, Aerosil 300 manufactured by Nippon Aerosil Co., Ltd.) are added to water. After the production, an inorganic fine particle dispersion A having a solid content concentration of 20% was produced by treatment with a high-pressure homogenizer. The average secondary particle diameter after dispersion was 100 nm.

[Example 74]
An ink jet recording material 74 was obtained in the same manner as in Example 5 except that the inorganic fine particle dispersion A in Example 5 was changed to the inorganic fine particle dispersion G.

[Example 75]
An ink jet recording material 75 was obtained in the same manner as in Example 8 except that the inorganic fine particle dispersion A in Example 8 was changed to the inorganic fine particle dispersion G.

[Example 76]
An ink jet recording material 76 was obtained in the same manner as in Example 10 except that the inorganic fine particle dispersion A in Example 10 was changed to the inorganic fine particle dispersion G.

[Example 77]
An ink jet recording material 77 was obtained in the same manner as in Example 13 except that the inorganic fine particle dispersion A in Example 13 was changed to the inorganic fine particle dispersion G.

[Example 78]
An ink jet recording material 78 was obtained in the same manner as in Example 14 except that the inorganic fine particle dispersion A in Example 14 was changed to the inorganic fine particle dispersion G.

[Example 79]
An ink jet recording material 79 was obtained in the same manner as in Example 2 except that the inorganic fine particle dispersion A in Example 2 was changed to the inorganic fine particle dispersion H.

<Inorganic fine particle dispersion H>
4 parts of dimethyldiallylammonium chloride homopolymer (molecular weight 9,000) and 100 parts of vapor phase process silica (average primary particle diameter 7 nm, specific surface area 300 m ² / g, Aerosil 300 manufactured by Nippon Aerosil Co., Ltd.) are added to water. After the production, an inorganic fine particle dispersion A having a solid content concentration of 20% was produced by treatment with a high-pressure homogenizer. The average secondary particle diameter after dispersion was 50 nm.

[Example 80]
An ink jet recording material 80 was obtained in the same manner as in Example 5 except that the inorganic fine particle dispersion A in Example 5 was changed to the inorganic fine particle dispersion H.

[Example 81]
An ink jet recording material 81 was obtained in the same manner as in Example 8, except that the inorganic fine particle dispersion A in Example 8 was changed to the inorganic fine particle dispersion H.

[Example 82]
An ink jet recording material 82 was obtained in the same manner as in Example 10 except that the inorganic fine particle dispersion A in Example 10 was changed to the inorganic fine particle dispersion H.

[Example 83]
An ink jet recording material 83 was obtained in the same manner as in Example 13 except that the inorganic fine particle dispersion A in Example 13 was changed to the inorganic fine particle dispersion H.

[Example 84]
An inkjet recording material 84 was obtained in the same manner as in Example 14 except that the inorganic fine particle dispersion A in Example 14 was changed to the inorganic fine particle dispersion H.

[Example 85]
An inkjet recording material 85 was obtained in the same manner as in Example 2 except that the amount of sodium chloride added in Example 2 was changed to 0.3 part.

[Example 86]
An inkjet recording material 86 was obtained in the same manner as in Example 5 except that the amount of magnesium chloride added in Example 5 was changed to 0.3 part.

[Example 87]
An ink jet recording material 87 was obtained in the same manner as in Example 8, except that the amount of sodium sulfate added in Example 8 was changed to 0.3 part.

[Example 88]
An inkjet recording material 88 was obtained in the same manner as in Example 10 except that the amount of magnesium sulfate added in Example 10 was changed to 0.3 part.

[Example 89]
An inkjet recording material 89 was obtained in the same manner as in Example 13 except that the amount of sodium amidosulfate added in Example 13 was changed to 0.3 part.

[Example 90]
An inkjet recording material 90 was obtained in the same manner as in Example 14 except that the amount of magnesium amidosulfate added in Example 14 was changed to 0.3 part.

[Example 91]
An inkjet recording material 91 was obtained in the same manner as in Example 2 except that the amount of sodium chloride added in Example 2 was changed to 1 part.

[Example 92]
An ink jet recording material 92 was obtained in the same manner as in Example 5 except that the amount of magnesium chloride added in Example 5 was changed to 1 part.

[Example 93]
An ink jet recording material 93 was obtained in the same manner as in Example 8 except that the amount of sodium sulfate added in Example 8 was changed to 1 part.

[Example 94]
An ink jet recording material 94 was obtained in the same manner as in Example 10 except that the amount of magnesium sulfate added in Example 10 was changed to 1 part.

[Example 95]
An ink jet recording material 95 was obtained in the same manner as in Example 13 except that the amount of sodium amidosulfate added in Example 13 was changed to 1 part.

[Example 96]
Inkjet recording material 96 was obtained in the same manner as in Example 14 except that the amount of magnesium amidosulfate added in Example 14 was changed to 1 part.

[Example 97]
An inkjet recording material 97 was obtained in the same manner as in Example 2 except that the amount of sodium chloride added in Example 2 was changed to 7 parts.

[Example 98]
An inkjet recording material 98 was obtained in the same manner as in Example 5 except that the amount of magnesium chloride added in Example 5 was changed to 7 parts.

Example 99
An inkjet recording material 99 was obtained in the same manner as in Example 8 except that the amount of sodium sulfate added in Example 8 was changed to 7 parts.

[Example 100]
An inkjet recording material 100 was obtained in the same manner as in Example 10 except that the amount of magnesium sulfate added in Example 10 was changed to 7 parts.

[Example 101]
Inkjet recording material 101 was obtained in the same manner as in Example 13 except that the amount of sodium amidosulfate added in Example 13 was changed to 7 parts.

[Example 102]
An inkjet recording material 102 was obtained in the same manner as in Example 14 except that the amount of magnesium amidosulfate added in Example 14 was changed to 7 parts.

From Examples 67 to 84, it can be seen that the average secondary particle diameter of the inorganic fine particle dispersion is 500 nm or less and the effects of the present invention are obtained.
From Examples 85-102, it can be seen that the amount of the smoothing agent added is 0.3 wt% or more and 7 wt% or less and the effects of the present invention are obtained.

[Comparative Example 1]
An ink jet recording material 103 was obtained in the same manner as in Example 1 except that hydrochloric acid in Example 1 was omitted.

[Comparative Example 2]
An inkjet recording material 104 was obtained in the same manner as in Comparative Example 1 except that the cumulative ultraviolet irradiation amount of Comparative Example 1 was changed to 1000 mJ / cm ² .

[Comparative Example 3]
An inkjet recording material 105 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to basic polyaluminum hydroxide.

[Comparative Example 4]
An ink jet recording material 106 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to sodium nitrate.

[Comparative Example 5]
An inkjet recording material 107 was obtained in the same manner as in Comparative Example 4 except that the cumulative ultraviolet ray irradiation amount of Comparative Example 4 was 1000 mJ / cm ² .

[Comparative Example 6]
An ink jet recording material 108 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to zinc nitrate hexahydrate.

[Comparative Example 7]
An inkjet recording material 109 was obtained in the same manner as in Comparative Example 6 except that the cumulative ultraviolet irradiation amount of Comparative Example 6 was set to 1000 mJ / cm ² .

[Comparative Example 8]
An inkjet recording material 110 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to sodium chloride and no ultraviolet irradiation was performed.

[Comparative Example 9]
An inkjet recording material 111 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to magnesium chloride and no ultraviolet irradiation was performed.

[Comparative Example 10]
An ink jet recording material 112 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to sodium sulfate and ultraviolet irradiation was not performed.

[Comparative Example 11]
An ink jet recording material 113 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to magnesium sulfate and no ultraviolet irradiation was performed.

[Comparative Example 12]
An ink jet recording material 114 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to sodium amidosulfate and no ultraviolet irradiation was performed.

[Comparative Example 13]
An ink jet recording material 115 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to bisamido magnesium sulfate and no ultraviolet irradiation was performed.

[Comparative Example 14]
Except that hydrochloric acid in Example 1 was changed to sodium chloride, and the resin was changed to resin H (non-modified polyvinyl alcohol: PVA-235 manufactured by Kuraray Co., Ltd., polymerization degree 3500, saponification degree 88 mol%). In the same manner as in Example 1, an inkjet recording material 116 was obtained.

[Comparative Example 15]
An ink jet recording material 117 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to magnesium chloride and the resin was changed to Resin H.

[Comparative Example 16]
An inkjet recording material 118 was obtained in the same manner as in Example 1, except that the hydrochloric acid in Example 1 was changed to sodium sulfate and the resin was changed to Resin H.

[Comparative Example 17]
An inkjet recording material 119 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to magnesium sulfate and the resin was changed to Resin H.

[Comparative Example 18]
An ink jet recording material 120 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to sodium amidosulfate and the resin was changed to Resin H.

[Comparative Example 19]
An inkjet recording material 121 was obtained in the same manner as in Example 1 except that the hydrochloric acid in Example 1 was changed to magnesium bisamidosulfate and the resin was changed to resin H.

The above-described evaluation was performed on the inkjet recording materials 103 to 121. The evaluation results are shown in Table 4.

In Comparative Example 1, since the inorganic salt of the present invention is not contained, cracks occur in the layer, and the pigment ink image density is significantly reduced. In Comparative Example 2, the cracking of the layer is eliminated and the pigment ink image density is increased by increasing the cumulative amount of UV irradiation compared to Comparative Example 1, but the deterioration of the support is promoted, and the environmental load during production (CO _2). This is not preferable because the increase in emission amount is large.
The basic polyaluminum hydroxide of Comparative Example 3 has no effect of preventing cracks, and the pigment ink image density is significantly reduced. The nitrates of Comparative Examples 4 to 7 do not stop the cracking of the layer even when the cumulative dose of ultraviolet rays is increased.
In Comparative Examples 8 to 13, when metal chloride and sulfate are added without ultraviolet irradiation, the effect of preventing cracking of the layer is not obtained and the pigment ink concentration is low.
Furthermore, if a resin that does not cross-link the resin is used, the layer cracks and the pigment ink image density is low.

Japanese Patent Publication 3-56552 JP-A-10-119423 JP 2000-2111235 A JP 2000-309157 A JP-A-9-286165 JP 10-181190 A JP 2001-277712 A JP-A-62-174183 JP-A-2-276670 JP-A-5-32037 JP-A-6-199034 JP 2002-254804 A JP 2000-27093 A JP 2001-96900 A JP-A 63-176173 JP 10-157283 A JP 2003-335043 A JP-A-2005-349613 JP-A-2005-349615

Claims (6)

An ink jet recording material having an ink receiving layer on a support, the ink receiving layer containing an ultraviolet crosslinking resin, an inorganic pigment, and a smoothing agent, wherein the smoothing agent is monovalent or divalent. An ink jet recording material characterized by being an inorganic acid or an inorganic salt thereof. 2. The ink jet recording material according to claim 1, wherein the ink receiving layer contains a smoothing agent in an amount of 0.3 wt% to 7 wt%. 3. The ink jet recording material according to claim 1, wherein the inorganic acid or an inorganic salt thereof is hydrochloric acid, sulfuric acid, amidosulfuric acid or a salt thereof. 4. The ink jet recording material according to claim 1, wherein the ultraviolet crosslinking resin has an acetoacetyl group, an acryloyl group, or a stilbazonium group.   The inkjet recording material according to any one of claims 1 to 4, wherein the inorganic pigment has an average secondary particle size of 500 nm or less.   6. The method for producing an ink jet recording material according to claim 1, wherein the ink receiving layer coating liquid is applied to the support on the support, and the coating liquid is irradiated with ultraviolet rays before the reduction rate drying. The method for producing an ink jet recording material, wherein the ink-receiving layer coating liquid comprises a resin that crosslinks when irradiated with ultraviolet rays, an inorganic pigment, and a smoothing agent.