JP2005119220A - Method for manufacturing recording medium and method for manufacturing inkjet recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a recording medium which specially shows high image resistance such as light resistance/anti-ozone properties; excellent surface smoothness/glossiness of a recording surface; is capable of forming a high-resolution/high-density; and free from the generation of a phenomenon such as tinting of paper surface; and less odorous, and a method for manufacturing an inkjet recording medium which especially shows high image resistance such as light resistance/anti-ozone properties; excellent surface smoothness/glossiness of a recording surface; is almost free from bleeding over time and the generation of a phenomenon such as tinting of a paper surface; is capable of forming a high-resolution/high-density image; and is less odorous. <P>SOLUTION: The method for manufacturing a recording medium uses at least an oxidation treatment liquid obtained by oxidatively treating a thioether compound and the method for manufacturing an inkjet recording medium includes a process to form an ink acceptance layer by applying a coating liquid for the ink acceptance layer to the surface of a support. In addition, the method for manufacturing an inkjet recording medium employs the oxidation treatment liquid obtained by oxidatively treating the thioether compound. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a recording medium, particularly an ink jet recording medium, which has less blurring of a recorded image and has good light resistance and ozone resistance.

  In recent years, with the rapid development of the information technology (IT) industry, various information processing systems have been developed, and a recording method and a recording apparatus suitable for each information processing system have been developed and put into practical use.

  Examples of recording methods that have been put to practical use include electrophotographic methods, ink jet recording methods, thermal recording methods, pressure sensitive recording methods, thermal transfer methods and the like in addition to silver salt photography. In any of the recording methods described above, it is required to obtain a high-quality image with sharp images and vivid colors.

  Among these recording methods, for example, the ink jet recording method is advantageous in that it can be recorded on various recording materials, hardware (equipment) is relatively inexpensive and compact, noise is low, and quietness is excellent. Therefore, it has been widely used not only in offices but also in so-called home use.

In addition, with the recent increase in resolution of inkjet printers, it has become possible to obtain so-called photographic-like high-quality recorded matter. With the advancement of such hardware (equipment), recording for inkjet recording is possible. Various seats have also been developed.
In the case of a recording sheet (medium) for ink jet recording, the required characteristics are generally (1) fast drying (high ink absorption speed), and (2) ink dot diameter is appropriate. And uniform (no blurring), (3) good granularity, (4) high dot roundness, (5) high color density, (6) saturation High (no dullness), (7) Good water resistance, light resistance and ozone resistance of the print area, (8) High whiteness of the recording sheet, (9) Preservability of the recording sheet Good (no yellowing coloration even after long-term storage, images do not bleed after long-term storage, good aging blur), (10) good deformation and good dimensional stability (sufficient curl (11) Hard (equipment) running is good It, and the like.
Furthermore, in the use of photo glossy paper used for the purpose of obtaining so-called photographic-like high-quality recorded matter, in addition to the above properties, glossiness, surface smoothness, texture of photographic paper similar to silver salt photography, etc. Is also required.

  In recent years, an ink jet recording sheet (ink jet recording medium) having a porous structure in an ink receiving layer has been developed and put into practical use for the purpose of improving the above-mentioned various characteristics. Such an ink jet recording sheet has a porous structure, so that it has excellent ink receptivity (fast drying property) and high gloss.

For example, an inkjet recording sheet is proposed in which an ink receiving layer containing inorganic pigment fine particles and a water-soluble resin and having a high porosity is provided on a support (see, for example, Patent Document 1 or 2).
These recording sheets, particularly ink jet recording sheets provided with an ink receiving layer having a porous structure using silica as inorganic pigment fine particles, are excellent in ink absorbability due to the porous structure, and form high-resolution images. It has a high ink receiving performance and can exhibit high gloss.

An ink jet recording sheet having a porous ink receiving layer containing silica fine particles and water-soluble aluminum is disclosed (see, for example, Patent Document 3), and water resistance and light resistance are maintained while maintaining glossiness and ink absorption. And that surface cracks are improved. Furthermore, examples using various sulfur-containing compounds are described (for example, see Patent Document 4), and there is a description that light resistance and surface cracking are improved while maintaining ink absorbability. Also disclosed is an ink jet recording sheet containing a sulfur-containing compound such as a sulfoxide compound in a porous ink receiving layer containing a silica dispersant, polyallylamine, polyvinylamine and the like (see, for example, Patent Document 5). There is a description that ozone resistance, light resistance, surface cracks, and blemishes are improved while maintaining absorption.
However, in any of the above-described ink jet recording sheets, the ink absorption and the improvement of surface cracks are maintained, but the silver halide photographic material level that can sufficiently satisfy all the image blurring, light resistance, and ozone resistance over a long period of time. It cannot be said that it has reached.

It is known that thioether compounds are effective for improving light resistance and ozone resistance. However, with regard to the thioether compound, it may not be possible to use a use amount sufficient to provide a sufficient effect due to insufficient water solubility and odor. This problem can occur not only in ink jet recording media but also in other recording media.
JP 10-119423 A Japanese Patent Laid-Open No. 10-217601 JP 2000-309157 A Japanese Patent No. 3377093 JP 2003-11498 A

An object of the present invention is to solve the conventional problems and achieve the following objects. That is,
The object of the present invention is particularly excellent in image resistance such as light resistance and ozone resistance, has surface smoothness and glossiness of the recording surface, enables high-resolution and high-density image formation, and coloration on the paper surface. It is an object of the present invention to provide a method for producing a recording medium that can produce a recording medium that produces less odor and the like and has less odor.
Another object of the present invention is, in particular, excellent image resistance such as light resistance and ozone resistance, surface smoothness and glossiness of the recording surface, little blurring with time, high resolution and high density image. It is an object of the present invention to provide an ink jet recording medium manufacturing method capable of forming an ink jet recording medium that can be formed, has little occurrence of coloring on the paper surface, and has little odor.

Means for solving the above-mentioned problems are as follows. That is,
<1> A method for producing a recording medium, comprising using at least an oxidation treatment liquid obtained by oxidizing a thioether compound.

<2> A method for producing an ink jet recording medium comprising a step of forming an ink receiving layer by applying an ink receiving layer coating liquid on a support, wherein the ink receiving layer coating liquid comprises at least a thioether compound. An ink jet recording medium manufacturing method comprising an oxidation treatment solution subjected to an oxidation treatment.

<3> The method for producing an ink jet recording medium according to <2>, wherein the oxidation treatment is performed with an oxidizing agent.

<4> The method for producing an inkjet recording medium according to <2> or <3>, wherein the oxidation treatment liquid is an aqueous solution.

<5> The method for producing an inkjet recording medium according to <3> or <4>, wherein the oxidizing agent is a hydrogen peroxide solution.

<6> The method for producing an ink jet recording medium according to <5>, wherein 1 equivalent of the hydrogen peroxide solution is used with respect to the thioether portion of the thioether compound.

<7> The method for producing an ink jet recording medium according to any one of <3> to <6>, wherein an unreacted oxidizing agent is treated with a reducing agent.

<8> The method for producing an ink jet recording medium according to any one of <2> to <7>, wherein the coating liquid for the ink receiving layer further contains a water-soluble polyvalent metal salt. .

According to the present invention, in particular, it has excellent image resistance such as light resistance and ozone resistance, has surface smoothness and glossiness of the recording surface, can form an image with high resolution and high density, and is colored on the paper surface. Thus, it is possible to provide a method for manufacturing a recording medium that can manufacture a recording medium that generates less odor and the like and has less odor.
Further, according to the present invention, in particular, an image having excellent image resistance such as light resistance and ozone resistance, surface smoothness and glossiness of a recording surface, little blurring with time, high resolution and high density image. It is possible to provide an ink jet recording medium manufacturing method capable of forming an ink jet recording medium that can be formed, causes less coloring of the paper surface, and has less odor.

Hereinafter, the manufacturing method of the recording medium and the manufacturing method of the ink jet recording medium of the present invention will be described in detail.
<Method for manufacturing recording medium>
The recording medium manufacturing method of the present invention is characterized in that at least an oxidation treatment liquid obtained by oxidizing a thioether compound is used. The method for producing a recording medium of the present invention can be applied to the production of an ink jet recording medium, a heat-sensitive recording material, a pressure-sensitive recording material, a photosensitive recording material, a transfer type recording material, and the like. Although it can be used for forming a layer such as a protective layer or an intermediate layer, it is preferable to use the thioether oxidation-treated body in the vicinity of the image forming portion, and therefore it is preferably used for forming the image recording layer.
In the present invention, by using the oxidation treatment liquid, particularly excellent image resistance such as light resistance and ozone resistance, surface smoothness and glossiness of the recording surface, and high-resolution and high-density image formation. Therefore, it is possible to produce a recording medium with little occurrence of coloring on the paper surface and less odor. Among these, the present invention can exhibit the most remarkable effect particularly when used in an inkjet recording medium, particularly an inkjet recording medium having a porous ink receiving layer.

  Hereinafter, the ink jet recording medium manufacturing method will be described. However, the following description of the oxidation treatment liquid will be described with respect to the recording medium manufacturing method. By replacing it with a coating solution, it is justified.

<Inkjet recording medium manufacturing method>
The method for producing an ink jet recording medium of the present invention is a method for producing an ink jet recording medium comprising a step of forming an ink receptive layer by applying a coating liquid for an ink receptive layer on a support, wherein the ink receptive layer coating method is applied. The liquid is characterized by containing at least an oxidation treatment liquid obtained by oxidizing a thioether compound.
Hereafter, the manufacturing method of the inkjet recording medium of this invention is demonstrated in detail.

  In the method for producing an ink jet recording medium of the present invention, at least one ink receiving layer is formed by applying an ink receiving layer coating liquid containing at least an oxidation treatment liquid obtained by oxidizing a thioether compound on a support. Here, “on the support” means not only the surface of the support but also the base layer when the base layer is provided on the support.

  In the present invention, the thioether compound having low solubility is not used as it is added to the ink receiving layer coating solution, but an oxidation treatment solution obtained by oxidizing the thioether compound is used as the ink receiving layer coating solution. In addition, the ink receiving layer is formed by the coating liquid for the ink receiving layer. In the oxidation treatment liquid, the thioether compound is oxidized to become a mixed liquid of thioether and sulfoxide (and sulfone), so that the solubility is improved and the odor can be suppressed. The sulfoxide compound is a preferable compound from the viewpoints of light resistance, improved ozone resistance, low odor, and solubility. However, it may be difficult to isolate or may have a low yield even if it can be isolated. The production method of the present invention is preferable because a sulfoxide compound can be quantitatively produced in a solution and no loss occurs. By using the oxidation treatment liquid, the production method of the present invention has good ink absorbability and glossiness, the blurring of the recorded image is sufficiently suppressed over a long period of time, and the light resistance and ozone resistance of the image are also improved. It is possible to produce an ink jet recording medium that is greatly improved and has less odor.

Examples of the method for performing the oxidation treatment include (1) using an oxidizing agent, (2) performing an electrical treatment, and (3) irradiating light. In (2) and (3), the substance in the system containing the thioether compound eventually acts as an oxidizing agent, but the oxidation reaction proceeds by external stimulation without adding the third component. Is intended.
Among the above, in the present invention, the oxidation treatment is preferably performed with an oxidizing agent.

As the oxidizing agent, various oxidizing agents can be used. As an example, a combination of an oxidizing agent and a solvent described in the chapter “Oxidations of Sulfides” (p.252-259) of “Oxidations in Organic Chemistry (author: Milos Hudlicky, published in 1990 by American Chemical Society)”. However, the present invention is not limited to this.
In the present invention, in order to use the oxidized oxidation solution as it is, hydrogen peroxide water or ozone water in which no by-product remains is preferable, and hydrogen peroxide water is particularly preferable. The concentration of the hydrogen peroxide solution is not particularly limited, but is preferably in the range of 5 to 70%, particularly preferably in the range of 10 to 50% from the viewpoint of reactivity and safety.

  In the oxidation treatment solution, the addition amount of the oxidizing agent is preferably 0.1 to 1.5 equivalents, more preferably 0.5 to 1.2 equivalents, relative to the thioether portion of the thioether compound. By making the addition amount of an oxidizing agent 0.1-1.5 equivalent, the effect of the solubility improvement of a thioether compound, odor reduction, and ozone resistance improvement can be exhibited. Moreover, when using hydrogen peroxide as an oxidizing agent, it is preferable to use 1 equivalent with respect to the thioether part of a thioether compound.

  In the oxidation treatment liquid, the solubility of the thioether itself is improved by the thioether compound becoming a mixture with the sulfoxide compound. The sulfoxide compound is particularly effective for a dye having a particularly high oxidation potential.

  Examples of the solvent for the oxidation treatment solution include water, alcohol, acetic acid, acetonitrile, and the chapter “Oxidations of Sulfides” in “Oxidations in Organic Chemistry (author: Milos Hudlicky, published in 1990 by American Chemical Society)” (p.252). ˜259) can be used. Further, since water-based coating is preferable for forming the ink receiving layer, the solvent of the oxidation treatment liquid is preferably water, alcohol, acetic acid, or acetonitrile. Especially, it is preferable that a solvent is water, ie, an oxidation treatment liquid is aqueous solution. In the case of an aqueous solution, since an organic solvent is not used, it is environmentally preferable.

  On the other hand, the water solubility of the sulfoxide compound produced by oxidizing the thioether compound is preferably high. Specifically, 5 g or more of a sulfoxide compound is preferably dissolved in 100 g of water, and more preferably 10 g or more is dissolved. Especially when the solubility of the thioether compound is low (specifically, the water solubility of the thioether compound is 5 g or less with respect to 100 g of water) and the sulfoxide compound produced by oxidation can be improved to the above-mentioned solubility. The effect is remarkable in the manufacturing method of the invention.

  Since the reaction when preparing an oxidation treatment solution by oxidizing a thioether compound with an oxidizing agent is basically a reaction accompanied by heat generation, the reaction can be accelerated by controlling the cooling rate of the reaction system and the addition rate of the oxidizing agent. It is preferable to take care not to proceed. Although reaction temperature is not specifically limited, The range of 0-60 degreeC is preferable and it is more preferable to set it as the range of 20-40 degreeC. By setting the temperature range to this range, the reaction does not proceed explosively, the reaction rate decreases, and the oxidizing agent does not remain excessively.

  In the oxidation treatment liquid, when an unreacted oxidant remains as a result of adding a large amount of oxidant, it is preferable to add a reducing agent to treat the unreacted oxidant. The reducing agent to be used is preferably one that reduces the added oxidizing agent but does not reduce the sulfoxide compound itself. Specific examples of such a reducing agent include sodium sulfite, sodium thiosulfate, and sodium hydrosulfite. The amount of the reducing agent used is preferably suppressed to the minimum amount necessary for treating the unreacted oxidizing agent from the viewpoint of reducing blurring.

  Although the structure of the thioether compound is not particularly limited, the production method of the present invention can exert its effect particularly for those having insufficient solubility and those having an odor. Specifically, methionine, 2- (ethylthio) ethanol, 3,6-dithia-1,8-octanediol and the like are effective.

In the ink-receiving layer coating solution, the content of thioether is preferably 0.01 to ²⁰ g / m ² in order to further improve ozone resistance, image blur and gloss, and 0.05 to 7 g. / more preferably m is ^2, and most preferably 0.1-2 g / m ^2.

  The thioether compound according to the present invention may be used alone or in combination of two or more.

  Specific examples of the thioether compound (Exemplary Compounds A-1 to A-77) are shown below, but the present invention is not limited thereto.

[Water-soluble polyvalent metal salt]
It is preferable that a water-soluble polyvalent metal salt is further added to the ink receiving layer coating solution. Specific examples of water-soluble polyvalent metal salts that can be suitably used in the present invention include the following.
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, cupric chloride, Ammonium copper (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel ammonium sulfate hexahydrate Japanese products, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum alum, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, ferrous bromide, ferric chloride Ferrous, ferric chloride, ferrous sulfate, ferric sulfate, phenolsulfone Zinc, zinc bromide, zinc chloride, zinc nitrate hexahydrate, zinc sulfate, titanium tetrachloride, tetraisopropyl titanate, titanium acetylacetonate, titanium lactate, zirconium acetylacetonate, zirconyl acetate, zirconyl sulfate, ammonium zirconium carbonate, Zirconyl stearate, zirconyl octylate, zirconyl nitrate, zirconium oxychloride, zirconium hydroxychloride, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate, citric acid Sodium tungsten, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, gallium nitrate, germanium nitrate, strontium nitrate, Yttrium acetate, yttrium chloride, yttrium nitrate, indium nitrate, lanthanum nitrate, lanthanum chloride, lanthanum acetate, lanthanum benzoate, cerium chloride, cerium sulfate, cerium octylate, praseodymium nitrate, neodymium nitrate, samarium nitrate, europium nitrate, gadolinium nitrate, Examples include dysprosium nitrate, erbium nitrate, ytterbium nitrate, hafnium chloride, and bismuth nitrate.

  Among these, aluminum-containing compounds (water-soluble aluminum compounds) such as aluminum sulfate, aluminum alum, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate; zirconium acetylacetonate Zirconyl acetate, zirconyl sulfate, ammonium zirconium carbonate, zirconyl stearate, zirconyl octylate, zirconyl nitrate, zirconium oxychloride, zirconium zirconium chloride and other zirconium-containing compounds (water-soluble zirconium compounds); and titanium tetrachloride, tetraisopropyl titanate, Titanium-containing compounds such as titanium acetylacetonate and titanium lactate are preferred, especially polyaluminum chloride, zirconyl acetate, zirconyl carbonate Ammonium, zirconium oxychloride is preferable.

In the method for producing an inkjet recording medium of the present invention, the content of the water-soluble polyvalent metal salt is 0.1 to 20 g / m ² in order to further improve ozone resistance, image blurring, and glossiness. Is preferable, 0.4 to 10 g / m ² is more preferable, and 0.8 to 5 g / m ² is more preferable.

  The water-soluble polyvalent metal salt may be used alone or in combination of two or more.

[Water-soluble resin]
The ink receiving layer coating liquid preferably contains a water-soluble resin.

Examples of the water-soluble resin include, for example, a polyvinyl alcohol resin that is a resin having a hydroxyl group as a hydrophilic structural unit [for example, polyvinyl alcohol (PVA), acetoacetyl-modified PVA, cation-modified PVA, anion-modified PVA, silanol-modified PVA, Polyvinyl acetals, etc.], cellulose resins [methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), hydroxyethyl methyl cellulose, hydroxypropyl methyl cellulose, etc.], chitins , Chitosans, starch, resins having an ether bond [eg, polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene Recall (PEG), poly ether (PVE)] and resins having carbamoyl groups [e.g., polyacrylamide (PAAM), polyvinyl pyrrolidone (PVP), polyacrylic acid hydrazide, etc.] and the like.
In addition, polyacrylates having a carboxy group as a dissociable group, maleic acid resins, alginates, gelatins, and the like can also be used.

Among these, polyvinyl alcohol (PVA) resin is particularly preferable. Examples of the polyvinyl alcohol include Japanese Patent Publication No. 4-52786, Japanese Patent Publication No. 5-67432, Japanese Patent Publication No. 7-29479, Japanese Patent No. 2537827, Japanese Patent Publication No. 7-57553, Japanese Patent No. 2502998, and Japanese Patent No. 3053231. JP-A-63-176173, JP-A-2604367, JP-A-7-276787, JP-A-9-207425, JP-A-11-58941, JP-A-2000-135858, JP-A-2001-205924, JP 2001-287444, JP 62-278080, JP 9-39373, JP 2750433, JP 2000-18801, JP 2001-213045, JP 2001-328345, JP 8 -324105, JP-A-11-348417, etc. It can be.
Examples of water-soluble resins other than polyvinyl alcohol resins include the compounds described in paragraph numbers [0011] to [0014] of JP-A No. 11-165461.

  These water-soluble resins may be used alone or in combination of two or more. In the ink jet recording medium of the present invention, the content of the water-soluble resin is preferably 9 to 40% by mass, and more preferably 12 to 33% by mass with respect to the total solid content of the ink receiving layer.

  In addition, the polyvinyl alcohol resin may be used in combination with the other water-soluble resin. When the other water-soluble resin and the polyvinyl alcohol-based resin are used in combination, the content of the polyvinyl alcohol-based resin in the total water-soluble resin is preferably 50% by mass or more, and more preferably 70% by mass or more.

[Fine particles]
The ink receiving layer coating liquid preferably contains fine particles, and more preferably, the fine particles and the water-soluble resin are used in combination.
When the ink receiving layer contains fine particles, a porous structure is obtained, thereby improving the ink absorption performance. In particular, when the solid content of the fine particles in the ink receiving layer is 50% by mass or more, more preferably more than 60% by mass, it becomes possible to form a porous structure having a higher porosity, and sufficient ink. It is preferable because an ink jet recording medium having absorbency can be obtained. Here, the solid content in the ink receiving layer of fine particles is a content calculated based on components other than water in the composition constituting the ink receiving layer.
Examples of the fine particles used in the present invention include organic fine particles and inorganic fine particles. From the viewpoint of ink absorbability and image stability, it is preferable to contain inorganic fine particles.

  The organic fine particles are preferably polymer fine particles obtained by, for example, emulsion polymerization, microemulsion polymerization, soap-free polymerization, seed polymerization, dispersion polymerization, suspension polymerization, and the like. Specifically, polyethylene, polypropylene, polystyrene, Examples include acrylate, polyamide, silicon resin, phenol resin, natural polymer powder, latex, or emulsion polymer fine particles.

Examples of the inorganic fine particles include silica fine particles, colloidal silica, titanium dioxide, barium sulfate, calcium silicate, zeolite, kaolinite, halloysite, mica, talc, calcium carbonate, magnesium carbonate, calcium sulfate, pseudoboehmite, zinc oxide, water. Examples thereof include zinc oxide, alumina, aluminum silicate, calcium silicate, magnesium silicate, zirconium oxide, zirconium hydroxide, cerium oxide, lanthanum oxide, and yttrium oxide. Among these, silica fine particles, colloidal silica, alumina fine particles, or pseudoboehmite are preferable from the viewpoint of forming a good porous structure. The fine particles may be used as primary particles or in a state where secondary particles are formed. The average primary particle size of these fine particles is preferably 2 μm or less, and more preferably 200 nm or less.
Further, silica fine particles having an average primary particle size of 20 nm or less, colloidal silica having an average primary particle size of 30 nm or less, alumina fine particles having an average primary particle size of 20 nm or less, or pseudoboehmite having an average pore radius of 2 to 15 nm is more preferable. In particular, silica fine particles, alumina fine particles, and pseudoboehmite are preferable.

  Silica fine particles are generally roughly classified into wet method fine particles and dry method (vapor phase method) fine particles according to the production method. In the above wet method, a method is mainly used in which activated silica is produced by acid decomposition of a silicate, and this is appropriately polymerized and agglomerated and precipitated to obtain hydrous silica. On the other hand, the above-mentioned vapor phase method is a method by high-temperature vapor phase hydrolysis of silicon halide (flame hydrolysis method), and silica sand and coke are heated and reduced and vaporized by an arc in an electric furnace and oxidized with air. The method of obtaining anhydrous silica by the method (arc method) is the mainstream, and “gas phase method silica” refers to anhydrous silica fine particles obtained by the gas phase method. As the silica fine particles used in the present invention, the latter “gas phase method silica” fine particles are particularly preferable.

The above-mentioned “gas phase method silica” is different from hydrous silica and the density of silanol groups on the surface or presence / absence of vacancies, etc. and shows different properties, but is suitable for forming a three-dimensional structure with high porosity. ing. The reason for this is not clear, but in the case of hydrous silica, the density of silanol groups on the fine particle surface is high at 5 to 8 / nm ² , and the silica fine particles tend to aggregate (aggregate) easily. In the case of silica, the density of silanol groups on the surface of the fine particles is 2 to 3 / nm ² , so that loose soft agglomerates are formed, resulting in a structure with a high porosity. It is estimated to be.

  The above-mentioned “gas phase method silica” has a particularly large specific surface area, so the ink absorbency and retention are high, and the refractive index is low. This is advantageous in that a high color density and good color developability can be obtained. In this way, the receiving layer is transparent, not only for applications that require transparency such as OHP, but also when applied to recording sheets such as photo glossy paper, high color density and good color developability and It is important in that gloss is obtained.

  The average primary particle diameter of the “gas phase method silica” is preferably 30 nm or less, more preferably 20 nm or less, particularly preferably 10 nm or less, and most preferably 3 to 10 nm. Since the vapor phase silica is easily attached to each other by hydrogen bonding with a silanol group, if the average primary particle size is 30 nm or less, a structure with a high porosity can be formed, and ink absorption characteristics are effective. Can be improved.

  Silica fine particles may be used in combination with the other fine particles. When the other fine particles and the vapor phase silica are used in combination, the content of the vapor phase silica in all the fine particles is preferably 30% by mass or more, and more preferably 50% by mass or more.

As the inorganic fine particles used in the present invention, alumina fine particles, alumina hydrate, a mixture or a composite thereof are also preferable. Of these, alumina hydrate is preferable because it absorbs and fixes ink well, and pseudoboehmite (Al ₂ O ₃ .nH ₂ O) is particularly preferable. The alumina hydrate can be used in various forms, but sol boehmite is preferably used as a raw material from the viewpoint of easily obtaining a smooth layer.

The average pore radius of the pseudoboehmite pore structure is preferably 1 to 30 nm, and more preferably 2 to 15 nm. The pore volume is preferably 0.3 to 2.0 ml / g, more preferably 0.5 to 1.5 ml / g. Here, the pore radius and pore volume are measured by a nitrogen adsorption / desorption method, and can be measured by, for example, a gas adsorption / desorption analyzer (for example, trade name “Omni Soap 369” manufactured by Coulter). .
Among alumina fine particles, vapor-phase method alumina fine particles are preferable because of their large specific surface area. The average primary particle size of the vapor phase alumina is preferably 30 nm or less, and more preferably 20 nm or less.

  When the fine particles are used in an ink jet recording medium, for example, JP-A-10-81064, JP-A-10-119423, JP-A-10-157277, JP-A-10-217601, JP-A-11-348409, JP-A-2001-138621. No. 2000-43401 No. 2000-2111235 No. 2000-309157 No. 2001-96897 No. 2001-138627 No. 11-91242 No. 8-2087 No. 8-2090 No. 8-2091, 8-2093, 8-174992, 11-192777, JP-A-2001-301314, and the like can also be preferably used.

The water-soluble resin and the fine particles, which mainly constitute the ink receiving layer in the present invention, may be a single material or a mixed system of a plurality of materials.
From the viewpoint of maintaining transparency, the type of water-soluble resin to be combined with fine particles, particularly silica fine particles, is important. When the vapor phase silica is used, the water-soluble resin is preferably a polyvinyl alcohol-based resin, more preferably a polyvinyl alcohol-based resin having a saponification degree of 70 to 100%, and particularly a saponification degree of 80 to 99. 5% polyvinyl alcohol resin is preferred.

The polyvinyl alcohol-based resin has a hydroxyl group in its structural unit, and since this hydroxyl group and the surface silanol group of the silica fine particle form a hydrogen bond, a three-dimensional network having a secondary particle of the silica fine particle as a network chain unit. It becomes easy to form a structure. By forming this three-dimensional network structure, it is considered that an ink receiving layer having a porous structure with a high porosity and sufficient strength is formed.
In ink jet recording, the porous ink-receiving layer obtained as described above can absorb ink rapidly by capillary action, and can form dots with good roundness without causing ink “bleeding”. .

(Content ratio of fine particles to water-soluble resin)
In the ink jet recording medium, the mass content ratio [PB ratio (x / y)] between the fine particles (x) in the ink receiving layer and the water-soluble resin (y) depends on the film structure and film strength of the ink receiving layer. It has a big impact. That is, when the mass content ratio [PB ratio] increases, the porosity, pore volume, and surface area (per unit mass) increase, but the density and strength tend to decrease.

  In the ink receiving layer according to the present invention, the mass content ratio [PB ratio (x / y)] prevents a decrease in film strength and cracks during drying caused by the PB ratio being too large, and When the PB ratio is too small, the voids are easily blocked by the resin, and from the viewpoint of preventing the ink absorbency from being lowered due to the decrease in the void ratio, 1.5 / 1 to 10/1 is preferable.

  Since stress may be applied to the recording sheet when passing through the conveyance system of the ink jet recording printer, the ink receiving layer needs to have sufficient film strength. Further, when cutting into a sheet shape, the ink receiving layer needs to have sufficient film strength in order to prevent cracking or peeling of the ink receiving layer. In consideration of these cases, the PB ratio (x / y) is more preferably 5/1 or less, while it is 2: 1 or more from the viewpoint of ensuring high-speed ink absorbability in an inkjet recording printer. Is more preferable.

Specifically, for example, a gas phase method silica fine particle having an average primary particle diameter of 20 nm or less and a water-soluble resin are completely dispersed in an aqueous solution at a PB ratio (x / y) of 2/1 to 5/1. When the liquid is coated on a support and the coating layer is dried, a three-dimensional network structure is formed in which secondary particles of silica fine particles are network chains, the average pore diameter is 30 nm or less, and the porosity is 50 to 80. %, A translucent porous film having a pore specific volume of 0.5 ml / g or more and a specific surface area of 100 m ² / g or more can be easily formed.

[Crosslinking agent]
The ink receiving layer coating liquid preferably further contains a crosslinking agent capable of crosslinking the water-soluble resin. Particularly, the fine particles and the water-soluble resin are used in combination, and the crosslinking agent and the water-soluble resin are further crosslinked. An embodiment that is a porous layer cured by reaction is preferred.

Boron compounds are preferred for crosslinking the water-soluble resin, particularly polyvinyl alcohol. Examples of the boron compound include borax, boric acid, borates (for example, orthoborate, InBO ₃ , ScBO ₃ , YBO ₃ , LaBO ₃ , Mg ₃ (BO ₃ ) ₂ , Co ₃ (BO ₃ ) ₂ , two Borate (eg, Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (eg, LiBO ₂ , Ca (BO ₂ ) ₂ , NaBO ₂ , KBO ₂ ), tetraborate (eg, Na _{2 B 4 O 7 · 10H 2} O), can be mentioned five borate _{(e.g., KB 5 O 8 · 4H 2} O, Ca 2 B 6 O 11 · 7H 2 O, CsB 5 O 5) or the like. Among them, Of these, borax, boric acid, and borate are preferable, and boric acid is particularly preferable in that a crosslinking reaction can be promptly caused.

Compounds other than the above boron compounds can also be used as a crosslinking agent for the water-soluble resin. For example,
Aldehyde compounds such as formaldehyde, glyoxal, succinaldehyde, glutaraldehyde, dialdehyde starch, dialdehyde derivatives of vegetable gum; ketones such as diacetyl, 1,2-cyclopentanedione, 3-hexene-2,5-dione Compounds; active halogen compounds such as bis (2-chloroethyl) urea, bis (2-chloroethyl) sulfone, 2,4-dichloro-6-hydroxy-s-triazine sodium salt; divinylsulfone, 1,3-bis (vinyl) Sulfonyl) -2-propanol, N, N′-ethylenebis (vinylsulfonylacetamide), divinylketone, 1,3-bis (acryloyl) urea, 1,3,5-triacryloyl-hexahydro-s-triazine, etc. Active vinyl compounds; dimethylolurea, methylol N-methylol compounds such as methylhydantoin; melamine compounds such as trimethylol melamine, alkylated methylol melamine, melamine, benzoguanamine, melamine resin; ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, diglycerin poly Epoxy compounds such as glycidyl ether, spiroglycol diglycidyl ether, polyglycidyl ether of phenol resin;

Isocyanate compounds such as 1,6-hexamethylene diisocyanate and xylylene diisocyanate; aziridine compounds described in U.S. Pat. Nos. 3,017,280 and 2,983611; and U.S. Pat. No. 3,100,704 Carbodiimide compounds; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; 2,3-dihydroxydioxane and the like Dioxane compounds; metal-containing compounds such as titanium lactate, aluminum sulfate, chromium alum, potash alum, zirconyl acetate and chromium acetate; polyamine compounds such as tetraethylenepentamine; hydrazide compounds such as adipic acid dihydrazide; 2 oxazoline groups Including more than Low molecule or polymer having: anhydride of polyvalent acid, acid described in US Pat. No. 2,725,294, US Pat. No. 2,725,295, US Pat. No. 2,726,162, US Pat. No. 3,834,902, etc. Examples include chloride and bissulfonate compounds; active ester compounds described in US Pat. No. 3,542,558, US Pat. No. 3,251972, and the like.
Said crosslinking agent may be used individually by 1 type, and can also be used in combination of 2 or more type.

In the present invention, the crosslinking and curing described above is performed by adding a crosslinking agent to a coating solution (hereinafter sometimes referred to as “coating solution A”) containing fine particles or a water-soluble resin and / or the following basic solution. And (1) at the same time when the coating solution is applied to form a coating layer, or (2) during the drying of the coating layer formed by coating the coating solution, and the coating layer exhibits a reduced rate of drying. It is preferable to carry out by applying a basic solution having a pH of 7.1 or higher (hereinafter sometimes referred to as “coating liquid B”) to the coating layer at any time before.
The application of the crosslinking agent is preferably carried out as follows, taking a boron compound as an example. That is, when the ink receiving layer is a layer obtained by crosslinking and curing a coating layer coated with a coating solution (coating solution A) containing a water-soluble resin containing fine particles and polyvinyl alcohol, the crosslinking curing is performed by (1) Either at the same time as the coating layer is formed by coating the coating solution, or (2) before the coating layer formed by coating the coating solution is dry and before the coating layer exhibits a reduced rate of drying. At that time, it is carried out by applying a basic solution (coating solution B) having a pH of 7.1 or higher to the coating layer. The boron compound as a cross-linking agent may be contained in either the coating solution A or the coating solution B, and may be contained in both the coating solution A and the coating solution B. As the coating solution B (basic solution), it is preferable to use a solution having a pH of 7.1 or more as described above, and more preferably between pH = 7.5 and 10.0.
The amount of the crosslinking agent used in the ink receiving layer in the invention is preferably from 1 to 50% by mass, more preferably from 5 to 40% by mass, based on the water-soluble resin.

[mordant]
The ink-receiving layer coating solution preferably contains a mordant in order to improve water resistance and aging resistance of the formed image.
As the mordant, a cationic polymer (cationic mordant) or an inorganic mordant is preferable as the organic mordant, and the liquid magenta having an anionic dye as a coloring material can be obtained by making the mordant present in the ink receiving layer. The interaction works to stabilize the color material and improve water resistance and aging resistance. Such an organic mordant and an inorganic mordant may be used alone, or an organic mordant and an inorganic mordant may be used in combination.

As a procedure for using the mordant, a method of adding to the coating liquid A containing fine particles and a water-soluble resin, or a method of adding to the coating liquid B and applying when there is a concern of aggregation between the fine particles. Both are available.
As the cationic mordant, a polymer mordant having a primary to tertiary amino group or a quaternary ammonium base as a cationic group is preferably used, but a cationic non-polymer mordant may also be used. it can. These mordants are preferably compounds having a mass average molecular weight of 500 to 100,000 from the viewpoint of improving the ink absorbability of the ink receiving layer.
Examples of the polymer mordant include a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base (mordant monomer), the mordant monomer and other monomers (hereinafter, Those obtained as a copolymer or a condensation polymer with "a non-mordant monomer") are preferred. Moreover, these polymer mordants can be used in any form of a water-soluble polymer or water-dispersible latex particles.

  Examples of the monomer (mordant monomer) include trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride, N , N-dimethyl-N-ethyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-Nn-propyl-N -P-vinylbenzylammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-die Ru-N-benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N- (4-methyl) benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-N -P-vinylbenzylammonium chloride;

  Trimethyl-p-vinylbenzylammonium bromide, trimethyl-m-vinylbenzylammonium bromide, trimethyl-p-vinylbenzylammonium sulfonate, trimethyl-m-vinylbenzylammonium sulfonate, trimethyl-p-vinylbenzylammonium acetate, trimethyl-m-vinyl Benzylammonium acetate, N, N, N-triethyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N, N-triethyl-N-2- (3-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride, N, N-diethyl-N-methyl-N-2- (4-vinylphenyl) ethylammonium chloride Tate;

  N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N- Methyl chloride, ethyl chloride, methyl bromide of dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide , Quaternized products of ethyl bromide, methyl iodide or ethyl iodide, or sulfonates, alkyl sulfonates, acetates or alkyl carboxylates substituted with their anions.

  Specific examples of the compound include monomethyl diallylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride, triethyl. 2- (acryloyloxy) ethylammonium chloride, trimethyl-3- (methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy) propylammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl-2 -(Methacryloylamino) ethylammonium chloride, trimethyl-2- (acryloylamino) ) Ethylammonium chloride, triethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) propyl Ammonium chloride, triethyl-3- (acryloylamino) propylammonium chloride;

N, N-dimethyl-N-ethyl-2- (methacryloyloxy) ethylammonium chloride, N, N-diethyl-N-methyl-2- (methacryloyloxy) ethylammonium chloride, N, N-dimethyl-N-ethyl- 3- (acryloylamino) propylammonium chloride, trimethyl-2- (methacryloyloxy) ethylammonium bromide, trimethyl-3- (acryloylamino) propylammonium bromide, trimethyl-2- (methacryloyloxy) ethylammonium sulfonate, trimethyl-3- And (acryloylamino) propylammonium acetate.
In addition, examples of copolymerizable monomers include N-vinylimidazole and N-vinyl-2-methylimidazole.

The non-mordant monomer does not include a basic or cationic moiety such as a primary to tertiary amino group and a salt thereof, or a quaternary ammonium base, and does not show an interaction with a dye in an inkjet ink. Or the monomer which interaction is substantially small is pointed out.
Examples of the non-mordant monomer include (meth) acrylic acid alkyl ester; (meth) acrylic acid cycloalkyl ester such as cyclohexyl (meth) acrylate; (meth) acrylic acid aryl ester such as phenyl (meth) acrylate; Aralkyl esters such as (meth) benzyl acrylate; aromatic vinyls such as styrene, vinyl toluene and α-methylstyrene; vinyl esters such as vinyl acetate and vinyl propionate; allyl esters such as allyl acetate; vinylidene chloride; And halogen-containing monomers such as vinyl chloride; vinyl cyanide such as (meth) acrylonitrile; and olefins such as ethylene and propylene.

The (meth) acrylic acid alkyl ester is preferably a (meth) acrylic acid alkyl ester having 1 to 18 carbon atoms in the alkyl moiety, for example, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) Propyl acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, Examples include 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, and the like.
Of these, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl methacrylate and the like are preferable.
The non-mordant monomers can also be used singly or in combination of two or more.

Further, as the polymer mordant, polydiallyldimethylammonium chloride, a copolymer of diallyldimethylammonium chloride and other monomers (mordant monomer, non-mordant monomer), a copolymer of diallyldimethylammonium chloride and SO ₂ , polydiallyl Cyclic amine resins represented by methylamine hydrochloride, polydiallyl hydrochloride, and derivatives thereof (including copolymers); polydiethylmethacryloyloxyethylamine, polytrimethylmethacryloyloxyethylammonium chloride, polydimethylbenzylmethacryloyloxyethylammonium chloride, Secondary amino, tertiary amino or quaternary ammonium salt substituted amides represented by polydimethylhydroxyethylacryloyloxyethylammonium chloride, etc. Kill (meth) acrylate polymers and copolymers with other monomers; polyamine resins represented by polyethyleneimine and derivatives thereof, polyallylamine and derivatives thereof, polyvinylamine and derivatives thereof, and the like; polyamide-polyamine resin, polyamide epi Polyamide resins typified by chlorohydrin resins, etc .; polysaccharides typified by cationized starch, chitosan and chitosan derivatives; dicyandiamide formalin polycondensates, dicyandiamide derivatives typified by dicyandiamide diethylenetriamine polycondensates, etc .; polyamidines and polyamidines Derivatives; Dialkylamine epichlorohydrin addition polymers such as dimethylamine epichlorohydrin addition polymers and derivatives thereof; having quaternary ammonium salt-substituted alkyl groups Styrene polymers and copolymers with other monomers may also be preferably exemplified.

  Specific examples of the polymer mordant include JP-A Nos. 48-28325, 54-74430, 54-124726, 55-22766, 55-142339, 60-23850, and 60. -23851, 60-23852, 60-23853, 60-57836, 60-60643, 60-118834, 60-122940, 60-122941, 60-122294 No. 60-235134, JP-A-1-161236, U.S. Pat.Nos. 2,484,430, 2,548,564, 3,148,061, 3,309,690, 4,115,124, 4,124,386, 4,193,800, 4,273,853, JP 4282305, JP 4450224, JP-A-1-16123. No. 10-81064, No. 10-157277, No. 10-217601, JP-A No. 2001-138621, No. 2000-212235, No. 2001-138627, JP-A No. 8-174992, No. 5-B 35162, 5-35163, 5-35164, 5-88846, Japanese Patent Nos. 2648847, 2616677 and the like.

As the mordant, an inorganic mordant can be used, and examples thereof include the water-soluble polyvalent metal salt and the hydrophobic metal salt compound.
Specific examples of the inorganic mordant include, for example, magnesium, aluminum, calcium, scandium, titanium, vanadium, manganese, iron, nickel, copper, zinc, gallium, germanium, strontium, yttrium, zirconium, molybdenum, indium, barium, lanthanum, Examples thereof include salts or complexes of metals selected from cerium, praseodymium, neodymium, samarium, europium, gadolinium, dysproprosium, erbium, ytterbium, hafnium, tungsten, and bismuth.

As the inorganic mordant, an aluminum-containing compound, a titanium-containing compound, a zirconium-containing compound, and a metal compound (salt or complex) of Group IIIB of the Periodic Table of Elements are preferable.
The content of the mordant in the ink-receiving layer in the present invention is preferably from ^{0.01g / m 2 ~5g / m 2} , 0.1g / m 2 ~3g / m 2 is more preferable.

[Other ingredients]
The ink-receiving layer coating liquid may further contain various known additives, such as acids, UV absorbers, antioxidants, fluorescent brighteners, monomers, polymerization initiators, polymerization inhibitors, and blur prevention, as necessary. Agents, preservatives, viscosity stabilizers, antifoaming agents, surfactants, antistatic agents, matting agents, anti-curling agents, water-proofing agents, and the like.

  In the present invention, the ink-receiving layer coating solution may contain an acid. By adding an acid, the surface pH of the ink receiving layer can be adjusted to 3 to 8, preferably 5 to 7.5. This is preferable because yellowing resistance of the white background portion is improved. The surface pH is measured by the A method (coating method) in the surface pH measurement determined by the Japan Paper Pulp Technology Association (J.TAPPI). For example, the measurement can be performed using a paper pH measurement set “Type MPC” manufactured by Kyoritsu Riken Co., Ltd., which corresponds to the above method A.

Specific examples of acids include formic acid, acetic acid, glycolic acid, oxalic acid, propionic acid, malonic acid, succinic acid, adipic acid, maleic acid, malic acid, tartaric acid, citric acid, benzoic acid, phthalic acid, isophthalic acid , Glutaric acid, gluconic acid, lactic acid, aspartic acid, glutamic acid, salicylic acid, salicylic acid metal salts (Zn, Al, Ca, Mg, etc.), methanesulfonic acid, itaconic acid, benzenesulfonic acid, toluenesulfonic acid, trifluoromethanesulfone Acid, styrenesulfonic acid, trifluoroacetic acid, barbituric acid, acrylic acid, methacrylic acid, cinnamic acid, 4-hydroxybenzoic acid, aminobenzoic acid, naphthalenedisulfonic acid, hydroxybenzenesulfonic acid, toluenesulfinic acid, benzenesulfinic acid, Sulfanilic acid, sulfamic acid, α-le Examples include ricinic acid, β-resorcinic acid, γ-resorcinic acid, gallic acid, phloroglicin, sulfosalicylic acid, ascorbic acid, erythorbic acid, bisphenolic acid, hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, boric acid, boronic acid, etc. It is done. The amount of these acids added may be determined so that the surface pH of the ink receiving layer is 3-8.
The above acids can be metal salts (eg sodium, potassium, calcium, cesium, zinc, copper, iron, aluminum, zirconium, lanthanum, yttrium, magnesium, strontium, cerium, etc.) or amine salts (eg ammonia, triethylamine, tri (Butylamine, piperazine, 2-methylpiperazine, polyallylamine, etc.).

  In the present invention, it is preferable that the ink receiving layer coating liquid contains a preservability improver such as an ultraviolet absorbent, an antioxidant, and a blurring inhibitor.

  Specific examples of the compound include Japanese Patent Application Nos. 2002-13005, 10-182621, 2001-260519, 4-34953, 4-34513, 11-170686, JP-B-4-34512, EP1138509, JP-A-60-67190, JP-A-7-276808, JP-A-2001-94829, JP-A-47-10537, JP-A-58-111942, and JP-A-58-212844. No. 59-19945, 59-46646, 59-109055, 63-53544, Sho 36-10466, 42-26187, 48-30492, 48-31255 48-41572, 48-54965, 50-10726, US Pat. No. 2,719,086, 3,707,375, 3,754,919, 4,220,711;

  Japanese Patent Publication Nos. 45-4699, 54-5324, European Published Patent Nos. 223739, 309401, 309402, 3105301, 310552, 457416, German Published Patent No. 3435443, Kaisho 54-48535, 60-107384, 60-107383, 60-125470, 60-125471, 60-125472, 60-287485, 60-287486, 60-287487, 60-287488, 61-160287, 61-18854, 61-2111079, 62-146678, 62-146680, 62-146679, 62- No. 282885, No. 62-262047, No. 63-051174, Nos. 63-89877, 63-88380 same issue, same 63-88381 JP, Nos. 63-113536;

  63-163351, 63-203372, 63-224989, 63-251282, 63-267594, 63-182484, JP-A-1-239282, JP-A-2-262654, 2-71262, 3-121449, 4-291865, 4-291684, 5-611166, 5-119449, 5-188687, 5-188686, 5 No. 110490, No. 5-110437, No. 5-170361, No. 48-43295, No. 48-33212, US Pat. Nos. 4,814,262, No. 4,980,275, and the like. .

As said other component, 1 type may be individual or 2 or more types may be used together. Such other components may be added after being water-solubilized, dispersed, polymer-dispersed, emulsified or oil-dropped, or may be encapsulated in microcapsules. In the inkjet recording medium of the present invention, the addition amount of the other components is preferably 0.01 to 10 g / m ² .

  Further, for the purpose of improving the dispersibility of the inorganic fine particles, the surface of the inorganic particles may be treated with a silane coupling agent or the like. Examples of the silane coupling agent include an organic functional group (for example, vinyl group, amino group (primary to tertiary amino group, quaternary ammonium base), epoxy group, mercapto, in addition to the site for coupling treatment. Group, chloro group, alkyl group, phenyl group, ester group, etc.)

In the present invention, the ink receiving layer coating solution preferably contains a surfactant. As the surfactant, any of cationic, anionic, nonionic, amphoteric, fluorine and silicon surfactants can be used.
Examples of the nonionic surfactant include polyoxyalkylene alkyl ethers and polyoxyalkylene alkyl phenyl ethers (for example, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, polyoxyethylene lauryl ether, polyoxyethylene stearyl ether, polyoxyethylene Ethylene nonylphenyl ether), oxyethylene / oxypropylene block copolymer, sorbitan fatty acid esters (for example, sorbitan monolaurate, sorbitan monooleate, sorbitan trioleate, etc.), polyoxyethylene sorbitan fatty acid esters (for example, polyoxyethylene) Sorbitan monolaurate, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan Lyolate, etc.), polyoxyethylene sorbitol fatty acid esters (eg, polyoxyethylene sorbitol tetraoleate), glycerin fatty acid esters (eg, glycerol monooleate), polyoxyethylene glycerin fatty acid esters (polyoxymonostearate) Ethylene glycerol, monooleic acid polyoxyethylene glycerin, etc.), polyoxyethylene fatty acid esters (polyethylene glycol monolaurate, polyethylene glycol monooleate, etc.), polyoxyethylene alkylamine, acetylene glycols (eg, 2, 4, 7) , 9-tetramethyl-5-decyne-4,7-diol, and ethylene oxide adducts, propylene oxide adducts, and the like of the diols), and polyoxy Ruki alkylene alkyl ethers are preferable. The nonionic surfactant can be used in a coating solution (A) and a coating solution (B) described later. Moreover, the said nonionic surfactant may be used independently and may use 2 or more types together.

  Examples of the amphoteric surfactant include amino acid type, carboxyammonium betaine type, sulfoammonium betaine type, ammonium sulfate betaine type, imidazolium betaine type and the like. For example, US Pat. No. 3,843,368, JP, JP-A-59-49535, JP-A-63-236546, JP-A-5-303205, JP-A-8-262742, JP-A-10-282619, JP-A-2514194, JP-A-2759597, JP-A-2000-351269, etc. Can be used preferably. Of the amphoteric surfactants, the amino acid type, carboxyammonium betaine type, and sulfoneammonium betaine type are preferable. The amphoteric surfactants may be used alone or in combination of two or more.

Examples of the anionic surfactant include fatty acid salts (for example, sodium stearate, potassium oleate), alkyl sulfate salts (for example, sodium lauryl sulfate, triethanolamine lauryl sulfate), and sulfonates (for example, dodecylbenzenesulfone). Acid sodium), alkylsulfosuccinate (for example, sodium dioctylsulfosuccinate), alkyl diphenyl ether disulfonate, alkyl phosphate, and the like.
Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, pyridinium salts, imidazolium salts, and the like.

Examples of the fluorosurfactant include compounds derived from an intermediate having a perfluoroalkyl group using a method such as electrolytic fluorination, telomerization, or oligomerization.
Examples include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl ethylene oxide adducts, perfluoroalkyl trialkyl ammonium salts, perfluoroalkyl group-containing oligomers, perfluoroalkyl phosphates, and the like.

  As the silicon surfactant, silicone oil modified with an organic functional group is preferable, and those obtained by modifying the side chain of the siloxane main chain structure with an organic group, those modified at both ends, and those modified at one end are mentioned. It is done. Examples of the organic functional group modification include amino modification, polyether modification, epoxy modification, carboxyl modification, carbinol modification, alkyl modification, aralkyl modification, phenol modification, and fluorine modification.

  In the present invention, the content of the surfactant is preferably 0.001 to 2.0%, more preferably 0.01 to 1.0% with respect to the coating liquid for the ink receiving layer. Further, when coating is performed using two or more liquids as the ink receiving layer coating liquid, it is preferable to add a surfactant to each coating liquid.

In the present invention, the ink receiving layer coating solution preferably contains a high boiling point organic solvent for curling prevention. The high-boiling organic solvent is an organic compound having a boiling point of 150 ° C. or higher at normal pressure, and is a water-soluble or hydrophobic compound. These may be liquid or solid at room temperature, and may be low molecules or polymers.
Specifically, aromatic carboxylic acid esters (for example, dibutyl phthalate, diphenyl phthalate, phenyl benzoate, etc.), aliphatic carboxylic acid esters (for example, dioctyl adipate, dibutyl sebacate, methyl stearate, malein) Dibutyl acid, dibutyl fumarate, triethyl acetylcitrate, etc.), phosphate esters (eg, trioctyl phosphate, tricresyl phosphate, etc.), epoxies (eg, epoxidized soybean oil, epoxidized fatty acid methyl, etc.), alcohols (For example, stearyl alcohol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, glycerin, diethylene glycol monobutyl ether (DEGMBE), triethylene glycol monobutyl ether, glycerin Phosphorus monomethyl ether, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,4-pentanetriol, 1,2,6-hexanetriol, thiodiglycol, triethanolamine, polyethylene glycol Etc.), vegetable oils (eg, soybean oil, sunflower oil, etc.) and higher aliphatic carboxylic acids (eg, linoleic acid, oleic acid, etc.).

[Support]
As the support used in the present invention, either a transparent support made of a transparent material such as plastic or an opaque support made of an opaque material such as paper can be used. In order to make use of the transparency of the ink receiving layer, it is preferable to use a transparent support or a highly glossy opaque support. In addition, a read-only optical disk such as a CD-ROM or DVD-ROM, a write-once optical disk such as a CD-R or DVD-R, or a rewritable optical disk is used as a support, and an ink receiving layer is provided on the label surface side. Can do.

As a material that can be used for the transparent support, a material that is transparent and has heat resistance that can withstand radiant heat when used in an OHP or a backlight display is preferable. Examples of such a material include polyesters such as polyethylene terephthalate (PET); polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide, and the like. Of these, polyesters are preferable, and polyethylene terephthalate (PET) is particularly preferable.
Although there is no restriction | limiting in particular as thickness of the said transparent support body, 50-200 micrometers is preferable at the point which is easy to handle.

  As the highly glossy opaque support, one having a glossiness of 40% or more on the surface on which the ink receiving layer is provided is preferable. The glossiness is a value determined according to the method described in JIS P-8142 (75-degree specular gloss test method for paper and paperboard). Specific examples of such a support include the following supports.

For example, high gloss paper support such as art paper, coated paper, cast coated paper, baryta paper used for silver salt photographic support, etc .; polyesters such as polyethylene terephthalate (PET), nitrocellulose, cellulose acetate , Cellulose esters such as cellulose acetate butyrate, and plastic films such as polysulfone, polyphenylene oxide, polyimide, polycarbonate, and polyamide are made opaque by adding a white pigment or the like (surface calendering may be applied). Glossy film; or a support in which a polyolefin coating layer containing or not containing a white pigment is provided on the surface of a highly glossy film containing the various paper supports, the transparent support or the white pigment. Etc.
A white pigment-containing foamed polyester film (for example, foamed PET containing polyolefin fine particles and forming voids by stretching) can also be suitably exemplified. Furthermore, resin-coated paper used for silver salt photographic printing paper is also preferable.

  Although there is no restriction | limiting in particular about the thickness of the said opaque support body, 50-300 micrometers is preferable at the point of the ease of handling.

  Further, it is desirable to use a surface of the support that has been subjected to corona discharge treatment, glow discharge treatment, flame treatment, ultraviolet irradiation treatment or the like in order to improve wettability and adhesion.

Next, the base paper used for the resin-coated paper will be described in detail.
As the base paper, wood pulp is used as a main raw material, and paper is made using synthetic pulp such as polypropylene or synthetic fiber such as nylon or polyester in addition to wood pulp as necessary. As the wood pulp, any of LBKP, LBSP, NBKP, NBSP, LDP, NDP, LUKP, and NUKP can be used, but more LBKP, NBSP, LBSP, NDP, and LDP with a larger amount of short fibers are used. preferable.
However, the content of LBSP and / or LDP is preferably 10% by mass to 70% by mass.

  The pulp is preferably a chemical pulp (sulfate pulp or sulfite pulp) with few impurities, and a pulp having a whiteness improved by bleaching is also suitable. In the base paper, sizing agents such as higher fatty acids and alkyl ketene dimers, white pigments such as calcium carbonate, talc and titanium oxide, paper strength enhancing agents such as starch, polyacrylamide and polyvinyl alcohol, fluorescent whitening agents, polyethylene glycol Moisture retention agents such as varieties, dispersants, softening agents such as quaternary ammonium, and the like can be added as appropriate.

  The freeness of the pulp used for papermaking is preferably 200 to 500 ml as defined by CSF, and the fiber length after beating is a 24 mesh residual mass% and a 42 mesh residual as defined in JIS P-8207. It is preferable that the sum with the mass% of is 30 to 70%. The 4 mesh residue is preferably 20% by mass or less.

The basis weight of the base paper is preferably 30 to 250 g, and particularly preferably 50 to 200 g. The thickness of the base paper is preferably 40 to 250 μm. The base paper can be given a high smoothness by performing a calendar process at the paper making stage or after paper making. The density of the base paper is generally 0.7 to 1.2 g / m ² (JIS P-8118).
Furthermore, the base paper stiffness is preferably 20 to 200 g under the conditions specified in JIS P-8143.

A surface sizing agent may be applied to the surface of the base paper. As the surface sizing agent, the same sizing agent as that which can be added to the base paper can be used.
The pH of the base paper is a value measured by a hot water extraction method defined in JIS P-8113, and is preferably 5-9.

  The polyethylene covering the front and back surfaces of the base paper is mainly low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), but some LLDPE, polypropylene, etc. can also be used.

  In particular, the polyethylene layer on the side that forms the ink-receiving layer is added with rutile or anatase-type titanium oxide and fluorescent brightening agent, ultramarine, in polyethylene, as is often done with photographic papers, What improved opacity, whiteness, and hue is preferable. Here, as titanium oxide content, 3-20 mass% is preferable with respect to polyethylene, and 4-13 mass% is more preferable. Although the thickness of a polyethylene layer is not specifically limited, 10-50 micrometers is suitable for both front and back layers. Further, an undercoat layer can be provided on the polyethylene layer in order to provide adhesion to the ink receiving layer. The undercoat layer is preferably water-based polyester, gelatin, or PVA. Further, the thickness of the undercoat layer is preferably 0.01 to 5 μm.

  Polyethylene-coated paper can be used as glossy paper, or it is a matte surface or silky surface that can be obtained with ordinary photographic printing paper by applying a so-called molding process in the process of extruding molten polyethylene onto the surface of the base paper and coating it. Can also be used.

A back coat layer can also be provided on the support, and examples of components that can be added to the back coat layer include white pigments, water-soluble binders, and other components.
Examples of the white pigment contained in the backcoat layer include light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin white, and silicic acid. White inorganic pigments such as aluminum, diatomaceous earth, calcium silicate, magnesium silicate, synthetic amorphous silica, colloidal silica, colloidal alumina, pseudoboehmite, aluminum hydroxide, alumina, lithopone, zeolite, hydrous halloysite, magnesium carbonate, magnesium hydroxide, Examples thereof include organic pigments such as styrene-based plastic pigments, acrylic-based plastic pigments, polyethylene, microcapsules, urea resins, and melamine resins.

Examples of the water-soluble binder used in the back coat layer include styrene / maleate copolymer, styrene / acrylate copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, and gelatin. Water-soluble polymers such as carboxymethyl cellulose, hydroxyethyl cellulose, and polyvinyl pyrrolidone, and water-dispersible polymers such as styrene butadiene latex and acrylic emulsion.
Examples of other components contained in the back coat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent brightening agent, a preservative, and a water resistant agent.

<Inkjet recording medium manufacturing method>
Next, the method for producing the ink jet recording medium of the present invention will be described more specifically.
In the method for producing an inkjet recording medium of the present invention, for example, the ink receiving layer is coated with a coating liquid A containing fine particles, a water-soluble resin and an oxidation treatment liquid on the support surface, and (1) the coating liquid is applied. At the same time as the coating layer is formed, or (2) during the drying of the coating layer formed by applying the coating solution and before the coating layer exhibits a reduced drying rate, the pH is 7. A method in which one or more coating solutions B (basic solution) are applied and a coating layer to which the coating solution B is applied is crosslinked and cured by adding a crosslinking agent to the coating solution A and / or the coating solution B It is preferably formed by (Wet-on-Wet method). Here, the oxidation treatment liquid according to the present invention is preferably contained in at least one of the first coating liquid (coating liquid A) or the second coating liquid (coating liquid B). Moreover, it is preferable that a crosslinking agent capable of crosslinking the water-soluble resin is also contained in at least one of the coating liquid A and the coating liquid B.
Providing an ink receiving layer that has been crosslinked and cured in this manner is preferable from the viewpoints of ink absorptivity and prevention of film cracking.

  This is preferable because a large amount of mordant is present near the surface of the ink receiving layer, so that the ink-jet coloring material is effectively sufficiently mordanted and the water resistance of characters and images after printing is improved. A part of the mordant may be contained in the coating liquid (A). In that case, the mordants of the coating liquid (A) and the coating liquid (B) may be the same or different.

In the present invention, the ink-receiving layer coating liquid (coating liquid (A)) containing at least fine particles (for example, vapor-phase process silica) and a water-soluble resin (for example, polyvinyl alcohol) is, for example, as follows. Can be prepared. That is,
Vapor phase silica fine particles and a dispersant are added to water (for example, silica fine particles in water are 10 to 20% by mass), and a high-speed rotating wet colloid mill (for example, “Clairemix” manufactured by M Technique Co., Ltd.) For example, at a high speed of 10,000 rpm (preferably 5000 to 20000 rpm), for example, after being dispersed for 20 minutes (preferably 10 to 30 minutes), then, a crosslinking agent (boron compound), polyvinyl alcohol (PVA) It can be prepared by adding an aqueous solution (for example, PVA having a mass of about 1/3 of that of the above-mentioned gas phase method silica) and dispersing under the same rotation conditions as described above. The obtained coating solution is in a uniform sol state, and can be formed on a support by the following coating method and dried to form a porous ink receiving layer having a three-dimensional network structure. .

In addition, the preparation of the aqueous dispersion composed of the above-mentioned vapor phase method silica and dispersant may be performed by preparing a vapor phase method silica aqueous dispersion in advance and adding the aqueous dispersion to the aqueous dispersion agent. The aqueous solution may be added to the vapor phase silica aqueous dispersion or may be mixed at the same time. Further, instead of vapor phase silica aqueous dispersion, powder vapor phase silica may be used and added to the aqueous dispersant as described above.
Vapor phase silica is preferably used as an aqueous dispersion using a dispersant because the glossiness of the ink jet recording medium is further improved.
After mixing said vapor phase silica and a dispersing agent, the mixed liquid is refined using a disperser, whereby an aqueous dispersion having an average particle diameter of 50 to 300 nm can be obtained. Dispersers used for obtaining the aqueous dispersion include conventionally known high-speed rotary dispersers, medium stirring dispersers (ball mill, sand mill, etc.), ultrasonic dispersers, colloid mill dispersers, high pressure dispersers and the like. Various dispersers can be used. From the viewpoint that the formed fine particles can be efficiently dispersed, a stirring disperser, a colloid mill disperser, or a high pressure disperser is preferable.

  Moreover, water, an organic solvent, or these mixed solvents can be used as a solvent in each process. Examples of the organic solvent that can be used for this coating include alcohols such as methanol, ethanol, n-propanol, i-propanol, and methoxypropanol, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran, acetonitrile, ethyl acetate, and toluene. It is done.

In addition, a chaotic polymer can be used as the dispersant. Examples of the chaotic polymer include the aforementioned mordants. It is also preferable to use a silane coupling agent as the dispersant.
In that case, it is preferable to use at least one dispersant selected from dispersant compounds having an I / O value of 2.0 or less in order to prevent aging blur. Here, the above I / O value is a parameter representing the scale of hydrophilicity / lipophilicity of a compound or a substituent, and detailed explanation is given in Yoshio Koda's “Organic Conceptual Diagram” (Sankyo Publishing, 1984). There is. I represents inorganic and O represents organic. The larger the I / O value, the greater the inorganicity (the higher the polarity and the higher the hydrophilicity).
The amount of the dispersant added to the fine particles is preferably 0.1% to 30%, more preferably 1% to 10%.

  In the present invention, the ink receiving layer coating liquid is applied by a known coating method such as an extrusion die coater, an air doctor coater, a bread coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, or a bar coater. It can be carried out.

  The coating liquid (B) is applied to the coating layer simultaneously with or after the coating of the ink receiving layer coating liquid (coating liquid (A)), and the coating liquid (B) is applied to the coating layer after coating. You may give before (A) comes to show a decreasing rate drying rate. That is, after the application of the ink-receiving layer coating liquid (coating liquid (A)), the mordant is preferably introduced while the coating layer exhibits a constant rate of drying.

  Here, “before the coating layer comes to exhibit a reduced rate of drying” usually refers to a process for several minutes immediately after the coating of the coating liquid for the ink receiving layer, and during this time, the coated coating layer is applied. This shows the phenomenon of “constant rate drying rate” in which the content of the solvent (dispersion medium) in the medium decreases in proportion to time. About the time which shows this "constant rate drying speed", it describes in "Chemical engineering handbook" (pages 707-712, Maruzen Co., Ltd. issue, October 25, 1980), for example.

  As described above, after the application of the first coating solution, the coating layer is dried until the coating layer exhibits a decreasing rate of drying. This drying is generally performed at a temperature of 50 to 180 ° C. for 0.5 to 10 minutes (preferably For 0.5 to 5 minutes). The drying time naturally varies depending on the coating amount, but the above range is usually appropriate.

  As a method of giving before the said 1st application layer comes to show a decreasing rate drying rate, (1) The method of further apply | coating a coating liquid (B) on an application layer, (2) By methods, such as a spray The method of spraying, (3) The method of immersing the support body in which this coating layer was formed in coating liquid (B), etc. are mentioned.

  In the method (1), examples of the application method for applying the coating liquid (B) include curtain flow coaters, extrusion die coaters, air doctor coaters, blade coaters, rod coaters, knife coaters, squeeze coaters, and reverse roll coaters. A known coating method such as a bar coater can be used. However, it is preferable to use a method in which the coater does not directly contact the already formed first coating layer, such as an extrusion die coater, a curtain flow coater, a bar coater, or the like.

  After the application of the mordant solution (coating liquid (B)), it is generally heated at a temperature of 40 to 180 ° C. for 0.5 to 30 minutes to be dried and cured. Especially, it is preferable to heat at a temperature of 40 to 150 ° C. for 1 to 20 minutes.

  When the mordant solution (coating liquid (B)) is applied simultaneously with the application of the ink receiving layer coating liquid (coating liquid (A)), the ink receiving layer coating liquid (coating liquid (A)) and the mordant solution ( The coating liquid (B)) is simultaneously coated (multilayer coating) on the support so that the ink receiving layer coating liquid (coating liquid (A)) is in contact with the support, and then dried and cured. A receiving layer can be formed.

  The above simultaneous application (multilayer application) can be performed, for example, by an application method using an extrusion die coater or a curtain flow coater. After the simultaneous coating, the formed coating layer is dried. In this case, the drying is generally performed by heating the coating layer at a temperature of 40 to 150 ° C. for 0.5 to 10 minutes, preferably at a temperature of 40 It is carried out by heating at -100 ° C for 0.5-5 minutes.

  When the above simultaneous coating (multilayer coating) is performed by, for example, an extrusion die coater, the two types of coating liquid discharged at the same time move near the discharge port of the extrusion die coater, that is, on the support. A multilayer is formed in advance, and the multilayer is applied on the support in that state. Since the two-layer coating liquid that has been layered before coating tends to cause a crosslinking reaction at the interface between the two liquids when transferred to the support, the two liquids that are discharged near the discharge port of the extrusion die coater. May become mixed and thicken easily, which may hinder the application work. Accordingly, when the simultaneous multi-layer coating is performed as described above, the barrier layer liquid (intermediate layer liquid) is used together with the ink receiving layer coating liquid (coating liquid (A)) and the mordant solution (coating liquid (B)). It is preferable to apply three layers simultaneously, interposing between the liquids.

  About the said barrier layer liquid, it can select without a restriction | limiting in particular. For example, an aqueous solution containing a trace amount of water-soluble resin, water, or the like can be given. The water-soluble resin is used in consideration of applicability for the purpose of a thickener and the like. For example, a cellulose resin (for example, hydroxypropylmethylcellulose, methylcellulose, hydroxyethylmethylcellulose) And polymers such as polyvinylpyrrolidone and gelatin. The barrier layer solution may contain the above mordant.

  After the ink receiving layer is formed on the support, the ink receiving layer is subjected to, for example, super calender, gloss calender, etc., and is subjected to calender treatment through the roll nip under heat and pressure, so that surface smoothness, glossiness, It is possible to improve transparency and coating strength. However, since the calendering process may cause a decrease in porosity (that is, a decrease in ink absorbency), it is important to set the conditions under which the decrease in porosity is small.

  As roll temperature in the case of performing a calendar process, 30-150 degreeC is preferable and 40-100 degreeC is more preferable. Moreover, as a linear pressure between rolls at the time of a calendar process, 50-400 kg / cm is preferable and 100-200 kg / cm is more preferable.

In the case of ink jet recording, the thickness of the ink receiving layer needs to have an absorption capacity sufficient to absorb all of the droplets, and therefore needs to be determined in relation to the porosity in the layer. For example, if the ink amount is 8 nL / mm ² and the porosity is 60%, a film having a layer thickness of about 15 μm or more is required. Considering this point, in the case of an ink jet recording medium, the thickness of the ink receiving layer is preferably 10 to 50 μm.

  The pore diameter of the ink receiving layer is preferably 0.005 to 0.050 μm, more preferably 0.01 to 0.035 μm in terms of median diameter. The porosity and pore median diameter can be measured using a mercury porosimeter (trade name “Boresizer 9320-PC2” manufactured by Shimadzu Corporation).

  In addition, the ink receiving layer is preferably excellent in transparency, as a guide, the haze value when the ink receiving layer is formed on a transparent film support is preferably 30% or less, More preferably, it is 20% or less. This haze value can be measured using a haze meter (for example, “HGM-2DP” manufactured by Suga Test Instruments Co., Ltd.).

  A dispersion of polymer fine particles may be added to a layer constituting the ink jet recording medium (for example, an ink receiving layer or a back layer). This polymer fine particle dispersion is used for the purpose of improving film physical properties such as dimensional stabilization, curl prevention, adhesion prevention, and film cracking prevention. The polymer fine particle dispersion is described in JP-A Nos. 62-245258, 62-1316648, and 62-110066. If a polymer fine particle dispersion having a low glass transition temperature (40 ° C. or lower) is added to the layer containing the mordant, cracking and curling of the layer can be prevented. Further, even when a polymer fine particle dispersion having a high glass transition temperature is added to the back layer, curling can be prevented.

  Ink jet recording media according to the present invention are disclosed in JP-A Nos. 10-81064, 10-119423, 10-157277, 10-217601, 11-348409, and JP-A-2001-138621. 2000-43401, 2000-2111235, 2000-309157, 2001-96897, 2001-138627, JP-A-11-91242, 8-2087, 8-2090, 8 It can also be produced according to the methods described in the publications Nos. -2091 and 8-2093.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. Here, “parts” and “%” in the examples represent “parts by mass” and “% by mass” unless otherwise specified.

[Production of support]
Wood pulp composed of 100 parts of LBKP is beaten to 300 ml Canadian freeness with a double disc refiner, 0.5 parts of epoxidized behenamide, 1.0 part of anionic polyacrylamide, 0.1 part of polyamide polyamine epichlorohydrin, 0.5 part of cationic polyacrylamide All parts were added at an absolutely dry mass ratio with respect to the pulp, and weighed with a long net paper machine to produce a base paper of 170 g / m ² .

In order to adjust the surface size of the base paper, 0.04% of a fluorescent whitening agent (“Whiteex BB” manufactured by Sumitomo Chemical Co., Ltd.) is added to a 4% aqueous solution of polyvinyl alcohol, and this is 0 in terms of absolute dry mass. The base paper was impregnated to a density of 0.5 g / m ² , dried, and then subjected to a calendering process to obtain a base paper adjusted to a density of 1.05 g / ml.

After the corona discharge treatment was performed on the wire surface (back surface) side of the obtained base paper, high-density polyethylene was coated to a thickness of 19 μm using a melt extruder to form a resin layer composed of a mat surface. (Hereinafter, the resin layer surface is referred to as “back surface”). The back side resin layer is further subjected to a corona discharge treatment, and thereafter, as an antistatic agent, aluminum oxide (“Alumina Sol 100” manufactured by Nissan Chemical Industries, Ltd.) and silicon dioxide (“Nissan Chemical Industries, Ltd. Snowtex O ") and a 1: a dispersion dispersed in water at 2 weight ratio, dry mass was applied as a 0.2 g / m ^2.

  Furthermore, after the corona discharge treatment is applied to the felt surface (surface) side where the resin layer is not provided, anatase-type titanium dioxide 10%, a trace amount of ultramarine blue, and a fluorescent whitening agent 0.01% (vs. polyethylene) A low-density polyethylene containing MFR (melt flow rate) 3.8 is extruded using a melt extruder to a thickness of 29 μm, and a high gloss thermoplastic resin layer is formed on the surface side of the base paper. (Hereinafter, this high-gloss surface is referred to as a “front side”), which was used as a support.

[Preparation of oxidation treatment solution]
(Preparation of oxidation treatment liquid 1)
To a suspension obtained by adding 14.9 g of DL-methionine to 30.6 g of water, 9.58 g of 30% hydrogen peroxide water (special grade product manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise. When the liquid which became uniform was confirmed by ¹ H-NMR, it was confirmed quantitatively that it was an aqueous solution of a sulfoxide form. Subsequently, it diluted with water to make 5% aqueous solution. As described above, the oxidation treatment liquid 1 was prepared.

(Preparation of oxidation treatment liquid 2)
To a suspension obtained by adding 14.9 g of DL-methionine to 58.9 g of water, 4.79 g of 30% hydrogen peroxide water (special grade product manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise. After completion of the dropwise addition, 236 g of water was added, and the uniform solution was confirmed by ¹ H-NMR. As a result, it was confirmed that the solution was an aqueous solution of thioether: sulfoxide = 1: 1 (molar ratio). Subsequently, it diluted with water to make 5% aqueous solution. As described above, an oxidation treatment liquid 2 was prepared.

(Preparation of oxidation treatment liquid 3)
To a suspension obtained by adding 14.9 g of DL-methionine to 58.6 g of water, 6.39 g of 30% hydrogen peroxide water (special grade product manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise. After completion of the dropwise addition, 97.7 g of water was added, and when the uniform liquid was confirmed by ¹ H-NMR, it was confirmed that the solution was an aqueous solution of thioether: sulfoxide = 1: 2 (molar ratio). Subsequently, it diluted with water to make 5% aqueous solution. As described above, the oxidation treatment liquid 3 was prepared.

(Preparation of oxidation treatment liquid 4)
9.58 g of 30% hydrogen peroxide solution (special grade product manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise to an emulsion prepared by mixing 10.6 g of 2- (ethylthio) ethanol with 20.5 g of water. When the liquid which became uniform after completion | finish of dripping was confirmed by < ¹ > H-NMR, it confirmed that it was quantitatively becoming the aqueous solution of a sulfoxide body. Subsequently, it diluted with water to make 5% aqueous solution. As described above, an oxidation treatment solution 4 was prepared.

(Preparation of oxidation treatment liquid 5)
To a suspension obtained by adding 37.3 g of DL-methionine to 74.6 g of water, 25.77 g of 30% hydrogen peroxide water (special grade product manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise. After completion of the dropwise addition, 1.22 g of sodium thiosulfate was added to the uniform solution. Then, it was confirmed by ¹ H-NMR, sulfoxide Sulfonated = 9: 1 was confirmed that it is an aqueous solution (molar ratio). Subsequently, it diluted with water to make 5% aqueous solution. The oxidation treatment liquid 5 was prepared as described above.

(Preparation of oxidation treatment liquid 6)
9.58 g of 30% hydrogen peroxide water (special grade product manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise to an aqueous solution obtained by adding 12.2 g of 2,2′-thiodiethanol to 24.3 g of water. When the liquid which became uniform was confirmed by ¹ H-NMR, it was confirmed quantitatively that it was an aqueous solution of a sulfoxide form. Subsequently, it diluted with water to make 5% aqueous solution. The oxidation treatment liquid 6 was prepared as described above.

(Preparation of oxidation treatment liquid 7)
To a suspension obtained by adding 18.23 g of 3,6-dithia-1,8-octanediol to 12.8 g of water, 19.2 g of 30% hydrogen peroxide water (special grade product manufactured by Wako Pure Chemical Industries, Ltd.) It was dripped. When the liquid which became uniform was confirmed by ¹ H-NMR, it was confirmed quantitatively that it was an aqueous solution of a disulfoxide body. Subsequently, it diluted with water to make 5% aqueous solution. As described above, the oxidation treatment liquid 7 was prepared.

[Example 1]
(Preparation of coating liquid A for ink receiving layer)
(1) Gas phase method silica fine particles, (2) ion-exchanged water, and (3) “Charol DC-902P” in the following composition are mixed, and a disperser “KD-P” manufactured by Shinmaru Enterprises Co., Ltd. (4) The oxidation treatment liquid 1, (5) polyaluminum chloride and (6) zirconyl acetate as a water-soluble polyvalent metal salt are added, and further dispersed using a disperser “KD-P”. I let you. Next, a solution containing (7) polyvinyl alcohol, (8) boric acid, (9) surfactant “Olfin PD-101”, and (10) ion-exchanged water is added to prepare a coating solution (A) for an ink receiving layer. did.
Here, the mass ratio between the silica fine particles and the water-soluble resin (PB ratio = (1) / (7)) is 4.5 / 1, and the pH of the coating liquid for ink-receiving layer (A) is 3.3. Showed acidity.

(Composition of coating liquid (A) for ink receiving layer)
(1) Gas phase method silica fine particles (inorganic fine particles) 10 parts (“Leosil QS-30” manufactured by Tokuyama Corporation, average primary particle diameter 7 nm)
(2) Ion-exchanged water 51.5 parts (3) Dispersant 1 part (Charol DC-902P, 51% aqueous solution, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
(4) Oxidation treatment liquid 1 6 parts (5) Polyaluminum chloride 0.6 part (40% aqueous solution, basic structure: Al ₂ (OH) ₅ Cl, basicity 83%, mordant)
(6) Zirconyl acetate (25% aqueous solution, mordant) 0.3 part (7) Polyvinyl alcohol (8% aqueous solution, water-soluble resin) 27.8 parts ("PVA235" manufactured by Kuraray Co., Ltd., saponification degree 88 mol%) , Degree of polymerization 3500)
(8) Boric acid water (5% aqueous solution, crosslinking agent) 8 parts (9) Surfactant (Olfin PD-101, manufactured by Nissin Chemical Industry Co., Ltd.) 0.1 part (10) Ion-exchanged water 19.7 Part

(Preparation of inkjet recording sheet)
After the corona discharge treatment is applied to the front surface of the support, the ink receiving layer coating solution (A) obtained above is applied to the front surface of the support at 200 ml / m ² using an extrusion die coater. It was applied in an amount (application step), and dried with a hot air dryer at 80 ° C. (wind speed 3 to 8 m / sec) until the solid content concentration of the application layer reached 20%. This coating layer exhibited a constant rate of drying during this period. Immediately after that, it was immersed in a mordant coating solution (B) having the following composition for 30 seconds to deposit 20 g / m ² on the coating layer (step of applying a mordant solution), and further dried at 80 ° C. for 10 minutes. (Drying process). Thus, an ink jet recording sheet (ink jet recording medium) of Example 1 provided with an ink receiving layer having a dry film thickness of 32 μm was produced.

(Composition of mordant coating liquid (B))
(1) Boric acid (crosslinking agent) 0.65 part (2) Ammonium zirconium carbonate 6.5 part ("Zircozol AC-7" 28% aqueous solution manufactured by Daiichi Elemental Chemical Co., Ltd.)
(3) Ammonium carbonate 6.0 parts (4) Ion-exchanged water 83.8 parts (5) Surfactant 0.2 parts (Mecha-Flick F-1405, manufactured by Dainippon Ink & Chemicals, Inc.)

[Example 2]
In Example 1 (Preparation of ink-receiving layer coating liquid A), the same procedure as in Example 1 was performed except that the oxidation treatment liquid 1 in the composition of the ink-receiving layer coating liquid A was changed to the oxidation treatment liquid 2. Thus, an inkjet recording sheet of Example 2 was produced.

[Example 3]
Example 1 (Preparation of coating liquid A for ink-receiving layer) In the same manner as Example 1 except that the oxidation treatment liquid 1 in the composition of the coating liquid A for ink-receptive layer was changed to the oxidation treatment liquid 3. Thus, an inkjet recording sheet of Example 3 was produced.

[Example 4]
Example 1 (Preparation of ink receiving layer coating liquid A) In the same manner as in Example 1 except that the oxidation treatment liquid 1 in the composition of the ink reception layer coating liquid A was changed to the oxidation treatment liquid 4. Thus, an inkjet recording sheet of Example 4 was produced.

[Example 5]
Example 1 (Preparation of ink-receiving layer coating liquid A) In the same manner as in Example 1 except that the oxidation treatment liquid 1 in the composition of the ink-receiving layer coating liquid A was changed to the oxidation treatment liquid 5. Thus, an inkjet recording sheet of Example 5 was produced.

[Example 6]
Example 1 (Preparation of ink-receiving layer coating liquid A) In the same manner as in Example 1 except that the oxidation treatment liquid 1 in the composition of the ink-receiving layer coating liquid A was changed to the oxidation treatment liquid 6. Thus, an inkjet recording sheet of Example 6 was produced.

[Example 7]
In Example 1 (Preparation of ink-receiving layer coating liquid A), the same procedure as in Example 1 was performed except that the oxidation treatment liquid 1 in the composition of the ink-receiving layer coating liquid A was changed to the oxidation treatment liquid 7. Thus, an inkjet recording sheet of Example 7 was produced.

[Comparative Example 1]
Ink jet of Comparative Example 1 in the same manner as in Example 1 except that the oxidation treatment liquid 1 in the composition of the coating liquid A for ink receiving layer was omitted in (Preparation of coating liquid A for ink receiving layer) of Example 1. A recording sheet was prepared.

[Comparative Example 2]
In Example 1 (Preparation of coating liquid A for ink-receiving layer), oxidation treatment liquid 1 in the composition of coating liquid A for ink-receiving layer was changed to a 5% suspension (water) of DL-methionine. An ink jet recording sheet of Comparative Example 2 was produced in the same manner as Example 1 except for the above.

[Comparative Example 3]
In Example 1 (Preparation of coating liquid A for ink-receiving layer), oxidation treatment liquid 1 in the composition of coating liquid A for ink-receiving layer was changed to a 5% liquid (water) of 2- (ethylthio) ethanol. Except that, an inkjet recording sheet of Comparative Example 3 was produced in the same manner as Example 1.

(Evaluation test)
The ink jet recording sheet obtained above was subjected to the following evaluation test, and the results are shown in Table 1 below.
(1) Image blurring test Each ink jet recording sheet is loaded into the paper feeding unit of an ink jet printer “PM-950C” manufactured by Seiko Epson Corporation, and the black ink for “PM-950C” is used. A 3 cm × 3 cm square pattern is formed by arranging a 1 mm white background gap to form a “field”, and a print pattern is created. This image sample is placed in an environment of temperature 25 ° C. and humidity 90% RH 72. After storage for a while, the black ink blur in the white background gap is visually observed, and the increase in the black density of the white background immediately after printing is 0.01 or less in the status A Bk filter (A), 0.01 The case of -0.05 was evaluated as (B), and the case of 0.05 or more was evaluated as (C).

(2) Light resistance test Each ink jet recording sheet was loaded into the paper feeding unit of an ink jet printer “PM-950C” manufactured by Seiko Epson Corporation, and an ink set for “PM-950C” was used. After printing a solid image of magenta, Xenon Weather-ometer “Ci65A” (manufactured by ATLAS) was passed through a filter that cuts out ultraviolet rays in a wavelength region of 365 nm or less under an environmental condition of a temperature of 25 ° C. and a humidity of 32% RH. A cycle of standing for 1 hour under an environmental condition of a temperature of 20 ° C. and a relative humidity of 91% with the lamp turned on for 3.8 hours and then turned off was performed for 168 hours. The density of the magenta image before and after this test was measured with a reflection densitometer “Xrite 938” manufactured by Xrite, and the residual ratio of magenta was calculated and evaluated according to the following criteria. Furthermore, the presence or absence of discoloration of the magenta image before and after the test was visually confirmed.
[Standard]
A: The density residual ratio of the magenta image exceeded 90%.
B: The density residual ratio of the magenta image was 80 to 90%.
C: The density residual ratio of the magenta image was 70 to 80%.
D: The residual density ratio of the magenta image was less than 70%.

(3) Evaluation of glossiness Each ink jet recording sheet is loaded into the paper feeding unit of an ink jet printer “PM-950C” manufactured by Seiko Epson Corporation, and the black ink for “PM-950C” is used. A 3 cm × 3 cm square solid print was performed. The glossiness of the black print portion was visually observed and evaluated according to the following criteria.
[Standard]
○ ………… High gloss and good quality.
Δ: The gloss was slightly inferior to the above.
X: The gloss was low and the result was poor.

(4) Coloring after storage The printed inkjet recording sheet is put in a file and stored in a constant temperature and humidity chamber at a temperature of 40 ° C. and a relative humidity of 90% for 4 days, and then at room temperature and humidity (23 ° C., 65% RH). ) For 3 days. The whiteness of the paper subjected to the above treatment was visually observed and evaluated according to the following evaluation criteria.
[Evaluation criteria]
○: The ink receiving layer was not colored.
Δ: Slight coloration of the ink receiving layer was observed.
X: The ink receiving layer was markedly colored.

(5) Ozone fading test Each ink jet recording sheet is loaded into the paper feeding unit of an ink jet printer “PM-950C” manufactured by Seiko Epson Corporation, and an ink set for “PM-950C” is used. Print a solid image of cyan, print a human and landscape image, leave it in an ozone atmosphere with a concentration of 3 ppm for 12 hours, and then visually observe the degree of coloration and color fading in each image and evaluate the following. Evaluation was made according to criteria.
[Evaluation criteria]
A: Almost no fading was observed.
○: Slight fading was observed.
Δ: A considerable fading was observed.
X: The degree of scarlet was remarkable.

  From the results shown in Table 1, the ink jet recording sheets of Examples 1 to 7 containing an oxidation treatment solution showed little light aging and coloration, and the formed images also showed high light resistance and ozone resistance. On the other hand, in Comparative Example 1 excluding the oxidation treatment liquid, although there was little aging blur and coloring, it was inferior in light resistance and ozone resistance. Moreover, in Comparative Examples 2 and 3 using a thioether compound alone instead of the oxidation treatment liquid, the gloss was inferior and the odor was present.

Claims (8)

  A method for producing a recording medium, comprising using an oxidation treatment liquid obtained by oxidizing at least a thioether compound. An ink jet recording medium manufacturing method comprising a step of applying an ink receiving layer coating liquid on a support to form an ink receiving layer,
The method for producing an ink jet recording medium, wherein the ink receiving layer coating liquid contains at least an oxidation treatment liquid obtained by oxidizing a thioether compound.   The method of manufacturing an ink jet recording medium according to claim 2, wherein the oxidation treatment is performed with an oxidizing agent.   The method for producing an ink jet recording medium according to claim 2, wherein the oxidation treatment liquid is an aqueous solution.   The method for producing an ink jet recording medium according to claim 3 or 4, wherein the oxidizing agent is a hydrogen peroxide solution.   6. The method for producing an ink jet recording medium according to claim 5, wherein 1 equivalent of the hydrogen peroxide solution is used with respect to the thioether portion of the thioether compound.   The method for producing an ink jet recording medium according to any one of claims 3 to 6, wherein an unreacted oxidizing agent is treated with a reducing agent.   The method for producing an ink jet recording medium according to any one of claims 2 to 7, wherein the coating liquid for the ink receiving layer further contains a water-soluble polyvalent metal salt.