JP2008213485A - Curl preventing method for inkjet recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a curl preventing method for an inkjet recording medium with few curls, which is flat and excellent in printer conveyability, without deteriorating ink receiving performance such as bleeding with time. <P>SOLUTION: In the curl preventing method for the inkjet recording medium having an ink receiving layer on a support body, a coating liquid containing at least particulates, a cationic polyurethane resin, a water soluble resin and a water-soluble polyvalent metal salt compound, and furthermore containing at least either of a sulfur-based organic matter and a hydrazine derivative, is coated on the support body to form a coating layer, and an ink receiving layer is formed by drying the coating layer. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

It relates curl prevention method of the present invention is an inkjet recording medium, the image of the bleeding with time is improved, and, to a curling method of preventing good inkjet recording medium curl is improved printer transportability.

  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. Among such recording methods, the inkjet recording method is advantageous in that it can be recorded on various recording materials, the hardware (device) is relatively inexpensive, is compact, and is excellent in low noise. 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 is also possible to obtain so-called photographic-like high-quality recorded materials, and along with the further development of hardware (device), various recording sheets for inkjet recording are also available. Improvements have been made.
The characteristics required for a recording sheet for ink jet recording are generally (1) fast drying (fast ink absorption speed), and (2) proper and uniform ink dot diameter (bleeding). (3) Good graininess, (4) High roundness of dots, (5) High color density, (6) High saturation (no dullness) ), (7) The light resistance and water resistance of the print portion are good, (8) The whiteness of the recording sheet is high, (9) The recording sheet has good storage stability (yellowing coloration during long-term storage) (10) hard to deform, good dimensional stability (curl is sufficiently small), (11) good running performance of hardware, Etc. 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 characteristics, glossiness, surface smoothness, texture of photographic paper similar to silver salt photography, etc. Required.

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

  For example, there has been proposed an ink jet recording medium containing fine inorganic pigment particles and a water-soluble resin and having an ink receiving layer having a high porosity on a support (for example, see Patent Documents 1 and 2). . These recording sheets, particularly ink jet recording media provided with an ink-receiving layer having a porous structure using silica as inorganic pigment fine particles, have excellent ink absorbability due to the structure, and high ink that can form a high-resolution image. It has a receptive performance and can exhibit high gloss.

  In addition, compounds having a tertiary amino group or a quaternary ammonium salt, particularly a polymer compound having these, have been widely added to inkjet recording media for the purpose of fixing the dye component of the ink. For example, a diallyl ammonium salt derivative (co) polymer (for example, see Patent Documents 3, 4, and 5), an allylamine salt copolymer (for example, see Patent Documents 6 and 7), and an ammonium salt (meta) ) Vinyl (co) polymers such as acrylate, (meth) acrylamide (co) polymers, vinylbenzylammonium salt (co) polymers (for example, see Patent Documents 8 to 14), modified polyvinyl alcohol (for example, patents) Numerous compounds such as amine-epichlorohydrin polyadducts (see, for example, Patent Documents 16 and 17) and polyamidines (see, for example, Patent Documents 18 and 19) have been used. By using these compounds to fix the dye, aging blur is prevented.

  However, all of these compounds are basically water-soluble polymers, and water-soluble dyes cannot be completely immobilized, and improvement in aging due to high temperature and high humidity is still insufficient. . Also, if the ink is stored in a clear file immediately after printing, high-boiling solvents (such as glycerin and diethylene glycol derivatives) contained in the ink and a small amount of ink remain in the ink. End up.

  Furthermore, even when the above-described means are used, when the printed image is stored in a clear file immediately after printing, or when it is stored for a long period of time particularly under high humidity conditions. However, there is also a problem that aging blur of the image occurs.

  In addition, an example is disclosed in which a hydrophobic vinylbenzylammonium salt cationic polymer that is water-insoluble but solvent-soluble is used instead of latex (see, for example, Patent Document 20). However, even when this is used, there is a problem that the light fastness of the image is lowered although the effect of improving the aging blur is high.

  For the above-mentioned problem, for example, the use of a cationic polymer having both a (meth) acrylate and / or (meth) acrylamide cationic moiety and a vinylbenzyl ammonium salt cationic moiety prevents aging blurring. However, even in these cases, the effect of improving the aging blur is still insufficient (see, for example, Patent Document 21).

  Further, it is described that aging blurring can be improved by using a (co) polymer of a vinylbenzylammonium salt-based water-soluble polymer (cation content is 40 mol% or more) (for example, patents) Reference 22). However, with this polymer, the aging blur is improved, but it causes a decrease in ink absorbency and a decrease in print density. Further, when silica is used as the fine particles, the dispersibility may be deteriorated.

  In this way, it is possible to form a high-resolution and high-density image with good ink absorbability, excellent image-storability (light resistance, ozone resistance, etc.), and especially for a long time in a high-temperature and high-humidity environment. At present, an ink jet recording medium that does not cause aging even when stored is not yet developed.

On the other hand, due to environmental changes such as humidity, the ink jet recording medium loses the balance of layer elongation on the front and back of the ink jet recording medium, and is in a state of being curled on one side, so-called curling has a quality problem. there were. Karl significantly lowers printers transportability, there is a problem that significantly reduces the product quality of the ink jet recording medium.

On the other hand, a method for solving the problem by laminating a support has been reported (for example, see Patent Documents 23 to 25).
JP-A-10-119423 Japanese Patent Laid-Open No. 10-217601 JP 60-83882 A JP-A 64-75281 JP 59-20696 A JP-A-61-61887 JP-A 61-72581 JP-A-6-340163 JP-A-4-288283 Japanese Patent Laid-Open No. 7-242055 Japanese Patent Laid-Open No. 9-300180 JP-A-8-318672 Japanese Patent Laid-Open No. 10-272830 JP 63-115780 A Japanese Patent Laid-Open No. 10-44588 JP-A-6-234268 JP 11-277888 A JP-A-11-58934 Japanese Patent Laid-Open No. 11-28860 JP 2000-239014 A JP 11-348409 A International Publication No. 99/64248 Pamphlet JP 2001-1632 A Japanese Patent Laid-Open No. 2001-212949 Japanese Patent Laid-Open No. 2002-166641

However, there is no method for reducing the curl in the ink receiving layer, and it has not been sufficient.
The present invention has been made in view of the above circumstances, and provides a method for improving the curl of an ink jet recording medium that is flat with less curl and excellent in printer transportability without deteriorating other ink receiving performance such as aging blur. The issue is to provide.

Means of the present invention for solving the above-mentioned problems are as follows. That is,
<1> A method for improving curling of an ink jet recording medium having an ink receiving layer on a support, comprising at least fine particles, a cationic polyurethane resin, a water-soluble resin, a water-soluble polyvalent metal salt compound, and a sulfur system on the support A method for improving curling of an ink jet recording medium , wherein an ink receiving layer is formed by applying a coating solution containing at least one of an organic substance and a hydrazine derivative to form a coating layer and drying .
<2> The method for improving curling of an ink jet recording medium according to <1>, wherein the cationic polyurethane resin is an aqueous dispersion.

<3> The method for improving curling of an ink jet recording medium according to <1>, wherein the water-soluble polyvalent metal salt compound is at least one selected from an aluminum compound, a zirconium compound, and a titanium compound.
<4> The water-soluble resin is at least one selected from polyvinyl alcohol resins, cellulose resins, resins having an ether bond, resins having a carbamoyl group, resins having a carboxyl group, and gelatins. The method for improving curling of an inkjet recording medium according to <1>.

<5> The method for improving curling of an ink jet recording medium according to <4>, wherein the water-soluble resin contains a cellulose resin.
<6> The method for improving curling of an ink jet recording medium according to <4>, wherein the water-soluble resin contains at least a polyvinyl alcohol resin having a saponification degree of 90% or less.

<7> The method for improving curling of an ink jet recording medium according to <1>, wherein the fine particles are at least one selected from silica fine particles, colloidal silica, alumina fine particles, and pseudoboehmite.
<8> The method for improving curling of an ink jet recording medium according to <1>, wherein the ink receiving layer contains a crosslinking agent , and at least one of them is boric acid and a boric acid compound.

<9> The method for improving curling of an ink jet recording medium according to <3>, wherein at least two kinds of the water-soluble polyvalent metal salt compounds are used in combination.
<10> the said crosslinking agent is added to the coating solution and / or the following basic solution, and (1) the same time as forming the coating layer by coating the coating liquid, or (2) by coating the coating liquid Crosslinking and curing by applying a basic solution having a pH of 7.5 or more to the coating layer at any time during the drying of the coating layer to be formed and before the coating layer exhibits a reduced rate of drying. The method for improving curling of an ink jet recording medium according to any one of the above <1> to <9>, wherein
<11> The method for improving curling of an ink jet recording medium according to <10>, wherein the basic solution contains at least an ammonium salt.
<12> A method for improving curling of an ink jet recording medium, wherein the surface pH of the ink jet recording medium according to <1> to <11> is 3 to 6.5.

According to the present invention, it is possible to provide a method for improving curling of an ink jet recording medium that is flat with less curling and excellent in printer transportability without lowering ink receiving performance and glossiness such as aging blur.

The method for improving curling of an ink jet recording medium of the present invention is a method for improving curling of an ink jet recording medium having an ink-receiving layer on a support, comprising at least fine particles, a cationic polyurethane resin, a water-soluble resin, and a water-soluble resin on the support . polyvalent metal salt compound, and by coating a coating solution containing at least any of the sulfur-based organic matter and hydrazine derivatives to form a coating layer, and forming an ink-receiving layer formed by drying.
Furthermore, the ink receiving layer can contain a dispersant, a surfactant, other additives, and the like as required or necessary. Further, another layer may be provided on the support.
In the present invention, the ink receiving layer is preferably formed on the support by the WOW method described later.
Hereinafter, the main configuration and production of the present invention will be described in detail.

(Sulfur-based organic matter)
As said sulfur type organic substance used for this invention, the thioether compound which has the alkyl group substituted by the group which has a hydrophilic group or a basic nitrogen atom is preferable, and the compound represented by following General formula (1) is mentioned. .

In the general formula (1), the R ₁ and R ₂ is independently, represent a hydrogen atom, a substituted or unsubstituted alkyl groups, a group containing an aryl group, or their substituted or unsubstituted, R ₁ or R ₂ are the same However, they may be different and may be combined to form a ring. However, at least one of R ₁ and R ₂ is a hydroxyl group, a sulfo group, a carboxy group, a hydrophilic group such as a (poly) ethyleneoxy group, or an amino group, an amide group, an ammonium group, a nitrogen-containing heterocyclic group, an aminocarbonyl group Group, an alkyl group substituted with a group having a basic nitrogen atom such as an aminosulfonyl group or a group containing the same (for example, this substituted alkyl group further includes a divalent linking group such as a carbamoyl group, a carbonyl group, a carbonyloxy group, etc. And may be bonded to the sulfur atom of the thioether. R ₃ may be substituted and optionally represents an alkylene group having an oxygen atom. m represents an integer of 0 to 10, and when m is 1 or more, at least one sulfur atom bonded to R ₃ may be a sulfonyl group.

Particularly preferred compounds of the general formula (1) are compounds having an alkyl group in which at least one of R ₁ and R ₂ is substituted with a hydroxy group, a carboxy group, an amino group, or an ammonium group. The amino group of the amino group-substituted alkyl group includes an amino group, a monoalkyl (preferably an alkyl group having 1 to 5 carbon atoms) substituted amino group, and a dialkyl (preferably an alkyl group having 1 to 5 carbon atoms) substituted amino group. And a nitrogen-containing heterocyclic group. Specific examples of the compound represented by the general formula (1) are shown below, but the present invention is not limited thereto.

The sulfur compounds may be used alone or in combination of two or more depending on the purpose. The content of the sulfur compound in the ink receiving layer is preferably from 0.1 to 10% by mass, more preferably from 0.3 to 5% by mass, and particularly preferably from 0.5 to 5% by mass based on fine particles described later. 4% by mass. By adding the sulfur organic material, gas resistance (ozone resistance) and light resistance can be remarkably improved.

(Fine particles)
The ink receiving layer in the present invention contains fine particles.
The fine particles may be inorganic fine particles or organic fine particles, preferably inorganic fine particles.
As the inorganic fine particles, inorganic pigment fine particles are suitable. Examples of the inorganic pigment 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, alumina, boehmite, pseudoboehmite, and the like. From the viewpoint of ink absorbability and high color developability, silica fine particles are particularly preferable.

  Since the fine particles have a particularly large specific surface area, the ink absorption and retention efficiency is high, and the refractive index is low. Therefore, if the dispersion is performed to an appropriate fine particle size, the ink receiving layer can be provided with transparency and high. There is an advantage that color density and good color developability can be obtained. Thus, the fact that the receiving layer is transparent means that not only for applications that require transparency, such as OHP, but also when applied to recording sheets such as photo glossy paper, a high color density and good color developability and This is important from the viewpoint of obtaining glossiness.

  The average primary particle diameter of the fine particles is preferably 20 nm or less, more preferably 15 nm or less, and particularly preferably 10 nm or less. When the average primary particle diameter is 20 nm or less, the ink absorption characteristics can be effectively improved, and at the same time, the glossiness of the ink receiving layer surface can be enhanced.

  In particular, the silica fine particle has a silanol group on the surface thereof, and the particles are likely to adhere to each other by hydrogen bonding of the silanol group, and because of the adhesion effect between the particles via the silanol group and the water-soluble resin, As described above, when the average primary particle size is 20 nm or less, the porosity of the ink receiving layer is large, a highly transparent structure can be formed, and the ink absorption characteristics can be effectively improved.

  In general, the silica fine particles are generally roughly classified into wet method particles and dry method (gas phase method) 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 gas phase method is a method by high-temperature gas phase hydrolysis of silicon halide (flame hydrolysis method), a method in which silica sand and coke are heated and reduced by an arc in an electric furnace and oxidized with air. The method of obtaining anhydrous silica by the (arc method) is the mainstream, and the “gas phase method silica” refers to anhydrous silica fine particles obtained by the gas phase method.

Vapor phase method silica is different from the above hydrous silica in the density of silanol groups on the surface, the presence or absence of vacancies, etc., and shows different properties, but is suitable for forming a three-dimensional structure with high porosity. The reason for this is not clear, but in the case of hydrous silica, the density of silanol groups on the surface of the fine particles is as high as 5 to 8 / nm ^2, and the silica fine particles tend to agglomerate closely (aggregate). In the case of the method silica, the density of silanol groups on the surface of the fine particles is as small as ² to 3 / nm ² , so that it becomes sparse soft agglomeration (flocculate), and as a result, it is estimated that the structure has a high porosity. The
In the present invention, vapor phase silica fine particles (anhydrous silica) obtained by the dry method are preferable, and silica fine particles having a density of 2 to 3 silanol groups / nm ² on the surface of the fine particles are more preferable.

  The organic fine particles are preferably polymer fine particles obtained by emulsion polymerization, microemulsion polymerization, soap-free polymerization, seed polymerization, dispersion polymerization, and the like. Specifically, polyethylene, polypropylene, polystyrene, polyacrylate polyamide, silicone resin, Mention may be made of phenolic resins, natural polymer powders, latex or emulsion polymer particles.

(Water-soluble resin)
The ink receiving layer in the invention further contains a water-soluble resin.
As the water-soluble resin, polyvinyl alcohol resins, cellulose resins, resins having an ether bond, resins having a carbamoyl group, resins having a carboxyl group, and gelatins are preferably used.
By adding a water-soluble resin, an ink receiving layer having a porous structure with a high porosity can be formed, the ink receiving ability can be improved, and the curl can be adjusted.

The polyvinyl alcohol-based resin can be appropriately selected from known ones. For example, polyvinyl alcohol (PVA), a cation-modified polyvinyl alcohol, and an anion-modified resin having a hydroxyl group as a hydrophilic structural unit. Polyvinyl alcohol, silanol-modified polyvinyl alcohol, polyvinyl acetal and the like can be mentioned.
The cellulose resin can be appropriately selected from known ones. For example, methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC) ), Hydroxypropyl methylcellulose (HPMC) and the like, and from the viewpoint of aging blur of the image, among them, methylcellulose (MC), hydroxyethylcellulose (HEC), hydroxypropylcellulose (HPC), hydroxypropylmethylcellulose (HPMC) are preferable, Furthermore, hydroxypropylcellulose (HPC) and hydroxypropylmethylcellulose (HPMC) are preferable.
The hydrophilic resin having an ether bond can be appropriately selected from known ones. For example, polyethylene oxide (PEO), polypropylene oxide (PPO), polyethylene glycol (PEG), polyvinyl ether (PVE) Etc.
The resin having a carbamoyl group includes a resin having a hydrophilic amide group or an amide bond, and can be appropriately selected from known ones. Polyacrylamide (PAAM), polyvinylpyrrolidone ( PVP) and the like.
The resin having a carboxyl group as the dissociable group can be appropriately selected from known ones, and examples thereof include polyacrylates, maleic resins, alginates, and gelatins. Furthermore, chitins, chitosans and starch can be mentioned.

As the content of the water-soluble resin, the decrease in the film strength and cracking at the time of drying due to the insufficient content, and the excessive content makes the voids easily blocked by the resin, From the viewpoint of preventing the ink absorbency from decreasing due to the decrease in the porosity, the amount is preferably 9 to 40% by mass, and more preferably 12 to 33% by mass with respect to the total solid mass of the ink receiving layer.
The fine particles and the water-soluble resin mainly constituting the ink receiving layer may be a single material or a mixed system of a plurality of materials.
When using the water-soluble resin in combination with a polyvinyl alcohol resin, a cellulose resin, a resin having an ether bond, a resin having a carbamoyl group, a resin having a carboxyl group, gelatins, etc., the total content thereof Is preferably included in the total solid content of 9 to 40% by mass.

  The polyvinyl alcohol (PVA) has a number average degree of polymerization of preferably 1800 or more, more preferably 2000 or more, from the viewpoint of preventing cracks. When combined with silica fine particles, the type of water-soluble resin is important from the viewpoint of transparency. In particular, when anhydrous silica is used, it is preferable to contain PVA as a water-soluble resin, a saponification degree of 90% or less is preferable, and 88% or less is preferable from the viewpoint of forming a three-dimensional network structure.

  Examples of the polyvinyl alcohol include cation-modified PVA, anion-modified PVA, silanol-modified PVA and other polyvinyl alcohol derivatives in addition to polyvinyl alcohol (PVA). Polyvinyl alcohol may be used alone or in combination of two or more.

  The PVA has a hydroxyl group in its structural unit, and this hydroxyl group and a silanol group on the surface of the silica fine particle form a hydrogen bond, and it is easy to form a three-dimensional network structure in which the secondary particle of the silica fine particle is a chain unit. To do. By forming such a three-dimensional network structure, it is considered that an ink receiving layer having a porous structure with a high porosity can be formed.

The cellulosic resin has a hydroxyl group in its structural unit, and this hydroxyl group and a silanol group on the surface of the silica fine particle form a hydrogen bond to form a three-dimensional network structure in which the secondary particle of the silica fine particle is a chain unit. Make it easy to do. By forming such a three-dimensional network structure, it is considered that an ink receiving layer having a porous structure with a high porosity can be formed.
Among the water-soluble resins, polyvinyl alcohol (PVA) -based resins and cellulose-based resins are more preferable, and they can be used alone or in combination, but polyvinyl alcohol (PVA) -based resins and cellulose-based resins can be used in combination. Is more preferable.

  In the ink jet recording medium, the porous ink receiving layer obtained as described above can absorb ink rapidly by capillary action and form dots with good roundness without ink bleeding.

(Content ratio of fine particles to water-soluble resin)
The content ratio of the fine particles (preferably silica fine particles; x) to the water-soluble resin (y) [PB ratio (x / y), the mass of inorganic pigment fine particles relative to 1 part by mass of the water-soluble resin] is the film structure of the ink receiving layer. It also has a big impact. That is, as the PB ratio increases, the porosity, pore volume, and surface area (per unit mass) increase. Specifically, as the PB ratio (x / y), a decrease in film strength and cracking during drying caused by the PB ratio being too large are prevented, and the PB ratio is too small. From the viewpoint of preventing the gap from being easily blocked by the resin and preventing the ink absorbability from being lowered due to a 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 printer, the ink receiving layer needs to have sufficient film strength. Further, when cutting into a sheet, the ink receiving layer needs to have sufficient film strength to prevent cracking and peeling of the ink receiving layer. From such a viewpoint, the PB ratio (x / y) is preferably 5/1 or less, and preferably 2/1 or more from the viewpoint of securing high-speed ink absorbability with an inkjet printer.

For example, a coating solution in which anhydrous silica fine particles having an average primary particle size of 20 nm or less and a water-soluble resin are completely dispersed in an aqueous solution with a PB ratio (x / y) of 2/1 to 5/1 is coated on a support. When the coating layer is dried, a three-dimensional network structure in which the secondary particles of silica fine particles are chain units is formed, the average pore diameter is 30 nm or less, the porosity is 50% to 80%, and the pore specific volume is 0. A translucent porous film having a surface area of 5 ml / g or more and a specific surface area of 100 m ² / g or more can be easily formed.

(Hydrazine derivative)
The ink receiving layer in the invention contains a hydrazine derivative.
By containing the hydrazine derivative in the ink receiving layer having a film surface pH of 3 to 6.5, preferably pH 3 to 5.5, the storage stability and water resistance after printing are remarkably improved based on the interaction with the vapor phase silica. Furthermore, the raw curl is improved.

  Examples of the hydrazine derivative used in the present invention include the following compounds.

Among of 1, R ₁ to R ₄ independently represent a hydrogen atom, a substituted or unsubstituted aliphatic group, an aromatic group, a heterocyclic group, a carbonyl group, a sulfonyl group, a sulfoxy group, a phosphoryl group, an iminomethylene group These may be linked to form a ring or may be a polymer.

  Examples of the substituent include an alkyl group, an aryl group, a heterocyclic group, an alkoxy group, an amino group, a hydrazino group, a carbonyl group, and a carbamoyl group. These substituents further have another substituent. It may be.

A hydrazine derivative having a substituted or unsubstituted carbonyl group or sulfonyl group in at least one of R _{1 to} R ₄ is particularly preferable. Examples of the hydrazine derivative used in the present invention include the following compounds.

The content in the ink-receiving layer of the hydrazine derivative used in the present invention, 0.1 to 50 mmol / m ² preferably is more preferably 0.2 to 20 mmol / m ^2.

(Water-soluble polyvalent metal salt compound)
The ink receiving layer in the present invention contains a water-soluble polyvalent metal compound.
By containing the water-soluble polyvalent metal compound in the ink receiving layer, it is possible to improve the water resistance and aging resistance of the formed image, and further improve the gas resistance, light resistance, etc. Become.
Examples of the water-soluble polyvalent metal salt compound used in the present invention include a water-soluble metal selected from calcium, barium, manganese, copper, cobalt, nickel, aluminum, iron, zinc, zirconium, chromium, magnesium, tungsten, and molybdenum. Salt.
Specifically, 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, second chloride Copper, ammonium chloride (II) chloride dihydrate, copper sulfate, cobalt chloride, cobalt thiocyanate, cobalt sulfate, nickel sulfate hexahydrate, nickel chloride hexahydrate, nickel acetate tetrahydrate, nickel ammonium sulfate Hexahydrate, nickel amidosulfate tetrahydrate, aluminum sulfate, aluminum sulfite, aluminum thiosulfate, polyaluminum chloride, aluminum nitrate nonahydrate, aluminum chloride hexahydrate, ferrous bromide, ferrous chloride Iron, ferric chloride, ferrous sulfate, ferric sulfate, zinc bromide, zinc chloride, zinc nitrate hexahydrate Zinc sulfate, zirconium acetate, zirconium chloride, zirconium chloride oxide octahydrate, hydroxy zirconium chloride, chromium acetate, chromium sulfate, magnesium sulfate, magnesium chloride hexahydrate, magnesium citrate nonahydrate, sodium phosphotungstate Sodium tungsten citrate, 12 tungstophosphoric acid n hydrate, 12 tungstosilicic acid 26 hydrate, molybdenum chloride, 12 molybdophosphoric acid n hydrate, and the like.

The water-soluble polyvalent metal salt compound is particularly preferably at least one selected from water-soluble aluminum compounds, zirconium compounds and titanium compounds.
As the aluminum compound, for example, aluminum chloride or a hydrate thereof, aluminum sulfate or a hydrate thereof, ammonium alum or the like is known as an inorganic salt. Furthermore, there is a basic polyaluminum hydroxide compound which is an inorganic aluminum-containing cationic polymer. In particular, a basic polyaluminum hydroxide compound is preferable.

The basic polyaluminum hydroxide compound is represented by the following formula 1, 2 or 3, for example, [Al ₆ (OH) ₁₅ ] ³⁺ , [Al ₈ (OH) ₂₀ ] ⁴⁺ , [ It is a water-soluble polyaluminum hydroxide containing a basic and high-molecular polynuclear condensed ion stably such as Al ₁₃ (OH) ₃₄ ] ⁵⁺ , [Al ₂₁ (OH) ₆₀ ] ³⁺ , and the like.

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

  These are water treatment agents from Taki Chemical Co., Ltd. under the name of polyaluminum chloride (PAC), from Asada Chemical Co., Ltd. under the name of polyaluminum hydroxide (Paho), and from Riken Green Co., Ltd. It is marketed under the name of Purachem WT and from other manufacturers for the same purpose, and various grades can be easily obtained. In the present invention, these commercially available products can be used as they are, but there are also products having an inappropriately low pH, and in that case, the pH can be appropriately adjusted and used.

The zirconium compound used in the present invention is not particularly limited and various compounds can be used. For example, zirconium acetate, zirconium chloride, zirconium oxychloride, hydroxy zirconium chloride, zirconium nitrate, basic zirconium carbonate, zirconium hydroxide Zirconium carbonate / ammonium, zirconium carbonate / potassium, zirconium sulfate, zirconium fluoride compound and the like.
The titanium compound is not particularly limited, and various compounds can be used. Examples thereof include titanium chloride and titanium sulfate.
Some of these compounds have an inappropriately low pH. In that case, the pH can be appropriately adjusted and used. In the present invention, the term “water-soluble” means that 1% by mass or more dissolves in water at room temperature and normal pressure.

  In the present invention, the content of the water-soluble polyvalent metal salt compound in the ink receiving layer is preferably 0.1 to 10% by mass, and more preferably 1 to 5% by mass with respect to the fine particles.

  Although the water-soluble polyvalent metal salt compound can be used alone, it is preferable to use two or more kinds in combination.

(Cationic polyurethane resin)
The ink receiving layer in the present invention contains the cationic polyurethane resin.
By containing the cationic polyurethane resin in the ink receiving layer, it is possible to improve the aging resistance of the formed image, the water resistance and the curl.
Further, by using the cationic polyurethane resin, at least one of the above sulfur-based organic substances and hydrazine derivatives, and three kinds of water-soluble polyvalent metal salt compounds in combination, particularly curling before printing is suppressed. The effect becomes remarkable.
The cationic polyurethane resin used in the present invention is not particularly limited, and various known ones can be used, and examples thereof include cationic polyurethane resins obtained by the following preparations (1) and (2). In particular, a composition in which a cationic polyurethane resin is dispersed in water, that is, an aqueous dispersion is preferable.

  The cationic polyurethane resin is prepared by (1) using a polyester polyol (B1) as a polyol for urethane reaction with the polyisocyanate (A), and using a chain extender (C) having a tertiary amino group as a urethane prepolymer. A cationic polyurethane resin is prepared by preparing a polymer and neutralizing a part of the tertiary amino group with an acid or quaternizing with a quaternizing agent so that the amine value is in the range of 1 to 40 (KOHmg / g). It can be obtained in the form of a composition. (2) Polycarbonate polyol (B2), chain extender (C) having a tertiary amino group, and polyalkylene oxide (D) containing 50% by weight or more of an ethylene oxide chain, the polyisocyanate (A) A cationic polyurethane resin can be obtained by preparing a urethane prepolymer using the above and neutralizing a tertiary amino group introduced by the chain extender (C) with an acid or quaternizing with a quaternizing agent. it can. By obtaining the cationic polyurethane resin in a form dispersed in water, it can be obtained as an aqueous dispersion.

Hereinafter, the preparation (1) will be described.
As the polyisocyanate (A) in the present invention, conventionally used polyisocyanates such as aliphatic, alicyclic, aromatic and araliphatic can be used.

  Specific examples of the aliphatic polyisocyanate include, for example, tetramethylene diisocyanate, dodecamethylene diisocyanate, 1,4-butane diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene. Examples thereof include diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, and 3-methylpentane-1,5-diisocyanate.

  Specific examples of the alicyclic polyisocyanate include, for example, isophorone diisocyanate, hydrogenated xylylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis (isocyanate). And methyl) cyclohexane.

  Specific examples of the aromatic polyisocyanate include, for example, tolylene diisocyanate, 2,2′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate and the like can be mentioned.

  Specific examples of the araliphatic polyisocyanate include dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, and α, α, α, α-tetramethylxylylene diisocyanate.

  These polyisocyanates can be used alone or in combination of two or more.

  As the polyester polyol (B1) used in the present invention, those composed of various polycarboxylic acids and polyols can be used, but dicarboxylic acids composed of aliphatic dibasic acids and aromatic dibasic acids. What is comprised with an acid and aliphatic glycol is more preferable at the point that adhesiveness becomes high. Examples of the aliphatic dibasic acid include malonic acid, succinic acid, tartaric acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, alkyl succinic acid, linolenic acid, maleic acid, fumaric acid , Mesaconic acid, citraconic acid, itaconic acid, glutaconic acid and the like, or reactive derivatives such as acid anhydrides, alkyl esters, acid halides, and the like. These aliphatic dicarboxylic acids can be used alone or in combination of two or more. Examples of the aromatic dibasic acid include phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, tetrahydro Examples thereof include phthalic acid and the like, or reactive derivatives thereof such as acid anhydrides, alkyl esters, and acid halides. These aromatic dicarboxylic acids can be used alone or in combination of two or more.

  As the aliphatic glycol in the present invention, ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 1, Examples include 6-hexanediol and propylene glycol, and these can be used alone or in combination of two or more.

  The chain extender (C) having a tertiary amino group in the molecule is used for introducing the tertiary amino group into the urethane prepolymer. Examples of such chain extenders (C) include N-alkyldialkanolamines such as N-methyldiethanolamine and N-ethyldiethanolamine, N-alkyldiaminoalkylamines such as N-methyldiaminoethylamine and N-ethyldiaminoethylamine, A triethanolamine etc. can be mentioned. These chain extenders (C) having a tertiary amino group can be used alone or in combination of two or more.

  The addition amount of the chain extender (C) in the preparation (1) is 5 to 20% by mass with respect to the total of the polyisocyanate (A), the polyester polyol (B1), and the chain extender (C). More preferred. If the amount of the chain extender (C) added is less than 5% by mass, the number of tertiary amino groups to be introduced decreases, and the tendency for the adhesion and water resistance of the ink to decrease appears. On the other hand, when the amount of the chain extender (C) added is more than 20% by mass, the effect of improving the adhesion and the water resistance of the ink corresponding to the added amount cannot be obtained, and the chain extender (C ) Urethane prepolymer with an increased amount of addition tends to be difficult to prepare.

  In the present invention, the free NCO at the end of the urethane prepolymer produced by the reaction of the polyisocyanate (A), the polyester polyol (B1), and the chain extender (C) having a tertiary amino group in the molecule. The content of is more preferably in the range of 1 to 5% by mass. When the content of this terminal free NCO is less than 1% by mass, it is not preferable because preparation of the urethane prepolymer becomes difficult. Moreover, when there is more content of terminal free NCO than 5 mass%, since the cohesion force of the water-based polyurethane resin obtained becomes high too much, it is unpreferable at the point of adhesiveness.

  In the present invention, a cationic urethane prepolymer in which a tertiary amino group introduced by the chain extender (C) and a part thereof are neutralized with an acid or quaternized with a quaternizing agent is prepared. When the tertiary amino group and a part thereof are neutralized with an acid, the acids include formic acid, acetic acid, propionic acid, butyric acid, lactic acid, malic acid, malonic acid, adipic acid and other organic acids, and hydrochloric acid, phosphoric acid, Mention may be made of inorganic acids such as nitric acid. These acids can be used alone or in combination of two or more.

  In addition, when quaternizing a tertiary amino group and a part thereof with a quaternizing agent, quaternizing agents include alkyl halides such as benzyl chloride and methyl chloride, sulfate esters such as dimethyl sulfate and diethyl sulfate. Etc. These quaternizing agents can be used alone or in combination of two or more.

  In the present invention, as described above, the tertiary amino group and a part thereof are not completely neutralized or quaternized, and only a part of the tertiary amino group is neutralized or quaternized. . The amount of the tertiary amino group left without being neutralized or quaternized is such that the amine value of the cationic polyurethane resin is 1 to 40 (KOHmg / g), and this amine value is neutralized with acid. Or it can adjust by quaternization.

Hereinafter, the preparation (2) will be described.
The polyisocyanate (A) used in the preparation (2) is the same as the polyisocyanate (A) used in the preparation (1) as described.
Examples of the polycarbonate polyol (B2) used in the preparation (2) include a reaction of glycols such as 1,4-butanediol, 1,6-hexanediol, and diethylene glycol with diphenyl carbonate and phosgene. And the like. These aromatic dicarboxylic acids can be used alone or in combination of two or more.

  The addition amount of the polycarbonate polyol (B2) in the present invention is 40 to 80 mass with respect to the total of the polyisocyanate (A), the polycarbonate polyol (B2), the chain extender (C), and the polyalkylene oxide (D2). % Is preferable. When the added amount of the polycarbonate polyol (B2) is less than 40% by mass, the weather resistance of the resulting urethane resin is lowered, and the tendency to be poor in adhesion to a plastic sheet is not preferable. On the other hand, if it is more than 80% by mass, the cohesive force of the resulting cationic polyurethane resin becomes insufficient and the water resistance decreases, which is not preferable.

  In the present invention, a polyalkylene oxide (D2) containing 50% by mass or more of an ethylene oxide chain is used as a constituent component of polyurethane. This polyalkylene oxide (D2) is used to increase the absorbability of the ink to be printed. Examples of such polyalkylene oxide (D2) include ethylene oxide, a copolymer of ethylene oxide and propylene oxide, and the like. These polyalkylene oxides (D2) can be used alone or in combination of two or more. As described above, the ethylene oxide chain in the polyalkylene oxide (D2) needs to be 50% by mass or more. If the content of the ethylene oxide chain is less than 50% by mass, the ability to absorb ink is lowered, which is not preferable.

  The addition amount of the polyalkylene oxide (D2) in the present invention is 3 to 10 with respect to the total of the polyisocyanate (A), the polycarbonate polyol (B2), the chain extender (C), and the polyalkylene oxide (D2). It is preferable that it is mass%. When the addition amount of the polyalkylene oxide (D2) is lower than 3% by mass, the ink absorbability becomes insufficient, which is not preferable. On the other hand, when the amount of polyalkylene oxide (D2) added is more than 10% by mass, the water resistance decreases, which is not preferable.

The chain extender (C) used in the preparation (2) is the same as in the preparation (1).
The addition amount of the chain extender (C) used in the preparation (2) is based on the total of the polyisocyanate (A), the polycarbonate polyol (B2), the chain extender (C), and the polyalkylene oxide (D). It is preferable that it is 5-15 mass%. When the amount of the chain extender (C) added is less than 5% by mass, the tertiary amino groups to be introduced are decreased, and the adhesion tends to be lowered. Moreover, when there is more addition amount of chain extender (C) than 15 mass%, since the effect which improves the adhesiveness corresponding to addition amount will not be acquired, it is unpreferable.

  Acid and quaternizing agent when the tertiary amino group introduced by the chain extender (C) used in the preparation (2) and a part thereof are neutralized with an acid or quaternized with a quaternizing agent Is the same as in the case of the preparation (1).

  In the preparation of the above (1) and (2), the cationic urethane prepolymer obtained by neutralizing or quaternizing the tertiary amino group and a part thereof is a polyamine compound as needed when dispersed in water. It may be prepared using (D1). Examples of polyamine compounds that can be used include, for example, amino groups such as hydrazides such as ethylenediamine, propylenediamine, diethylenetriamine, hexylenediamine, triethylenetetramine, tetraethylenepentamine, isophoronediamine, piperazine, diphenylmethanediamine, hydrazine, and adipic acid dihydrazide. And a compound having two or more.

  In the preparations (1) and (2), a polyol having 3 or more hydroxyl groups may be added. When a polyol having 3 or more hydroxyl groups is added, adhesion to a plastic sheet can be improved. However, it is necessary to use the obtained cationic polyurethane resin as long as the dispersibility in water is not impaired. Examples of such polyols include sorbitol, 1,2,3,6-hexanetetraol, 1,4-sorbitan, 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerin, trimethylol. Ethane, trimethylolpropane, pentaerythritol and the like can be mentioned, and these can be used alone or in combination of two or more.

  In the preparation of the above (1) and (2), the cationic urethane prepolymer obtained by neutralizing or quaternizing the tertiary amino group or part thereof as described above is then dispersed in water. The cationic polyurethane resin used in the present invention and the dispersion thereof are obtained.

  The cationic polyurethane resin in the present invention can also be used in the form of the dispersant having the water-soluble resin. The content of the cationic polyurethane resin in the ink receiving layer is preferably 0.1 to 30% by mass, more preferably 3 to 15% by mass, and particularly preferably 5 to 10% by mass with respect to the fine particles. is there.

  Moreover, the form which further contained the inorganic water absorbing material may be sufficient as the cationic polyurethane resin in this invention. Inorganic water-absorbing materials include light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium oxide, zinc oxide, zinc sulfate, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, none Examples thereof include regular silica, aluminum hydroxide, alumina, ritbon, etc. Amorphous silica is preferable from the viewpoint of printing speed and color developability.

By using the cationic polyurethane resin in the present invention, it can be applied to sheets of soft polyvinyl chloride, semi-rigid polyvinyl chloride, rigid polyvinyl chloride, PET, polypropylene, polyethylene and the like.

  For the cationic polyurethane resin in the present invention, the resins described in JP-A-2002-307811, paragraphs 0006 to 0048 and JP-A-2002-307812, paragraphs 0006 to 0053 can be used.

(Crosslinking agent)
The ink receiving layer definitive to the invention comprises fine particles, a water-soluble resin preferably comprises a crosslinking agent capable of crosslinking the water-soluble resin is a porous layer cured by cross-linking reaction of the water-soluble resin by the crosslinking agent .

As the cross-linking agent, a suitable one may be appropriately selected in relation to the water-soluble resin contained in the ink-receiving layer. Among them, a boron compound is preferable in that the cross-linking reaction is rapid, and examples thereof include borax and boric acid. , borates (eg, _{orthoborate, InBO 3, ScBO 3, YBO} 3, LaBO 3, Mg 3 (BO 3) 2, Co 3 (BO 3) 2, two borates (e.g., Mg ₂ B ₂ O ₅ , Co ₂ B ₂ O ₅ ), metaborate (for example, LiBO ₂ , Ca (BO ₂ ) ₂ , NaBO ₂ , KBO ₂ ), tetraborate (for example, Na ₂ B ₄ O ₇ .10H ₂ O), And pentaborates (for example, KB ₅ O ₈ .4H ₂ O, Ca ₂ B ₆ O ₁₁ .7H ₂ O, CsB ₅ O ₅ ), etc. Of these, boric acid, boric acid compounds, borax and borates are preferable, and boric acid is particularly preferable. It is most preferable to use this in combination with polyvinyl alcohol which is a water-soluble resin.

  In the present invention, the crosslinking agent is preferably contained in an amount of 0.05 to 0.50 parts by mass, and 0.08 to 0.30 parts by mass with respect to 1.0 part by mass of the water-soluble resin. More preferably. When the content of the crosslinking agent is within the above range, the water-soluble resin can be effectively crosslinked to prevent cracks and the like.

When gelatin is used as the water-soluble resin, the following compounds other than boron compounds can also be used as a crosslinking agent.
For example, aldehyde compounds such as formaldehyde, glyoxal, and glutaraldehyde; ketone compounds such as diacetyl and cyclopentanedione; bis (2-chloroethylurea) -2-hydroxy-4,6-dichloro-1,3,5- Active halogen compounds such as triazine and 2,4-dichloro-6-S-triazine sodium salt; divinylsulfonic acid, 1,3-vinylsulfonyl-2-propanol, N, N′-ethylenebis (vinylsulfonylacetamide) ), Active vinyl compounds such as 1,3,5-triacryloyl-hexahydro-S-triazine; N-methylol compounds such as dimethylolurea and methyloldimethylhydantoin; melamine resins (for example, methylolmelamine, alkylated methylolmelamine) ;Epoxy resin;

  Isocyanate compounds such as 1,6-hexamethylene diisocyanate; Aziridine compounds described in US Pat. Nos. 3,017,280 and 2,983,611; Carboximide compounds described in US Pat. No. 3,100,704; Glycerol triglycidyl Epoxy compounds such as ether; Ethyleneimino compounds such as 1,6-hexamethylene-N, N′-bisethyleneurea; Halogenated carboxaldehyde compounds such as mucochloric acid and mucophenoxycyclolic acid; 2,3-dihydroxy Dioxane compounds such as dioxane; Titanium lactate, aluminum sulfate, chromium alum, potash alum, metal-containing compounds such as zirconyl acetate and chromium acetate, polyamine compounds such as tetraethylenepentamine, and hydrazide compounds such as adipic acid dihydrazide It is a small molecule or polymer or the like containing an oxazoline group two or more. The above crosslinking agents may be used alone or in combination of two or more.

  In the present invention, the cross-linking agent may be added to the ink receiving layer coating solution and / or the coating solution for forming the adjacent layer of the ink receiving layer when forming the ink receiving layer, or The above-mentioned coating solution for ink-receiving layer is coated on a support on which a coating solution containing a crosslinking agent has been applied in advance, or a coating solution for ink-receiving layer that does not contain a crosslinking agent is coated and dried, and then the coating solution is overcoated For example, a crosslinking agent can be supplied to the ink receiving layer. Preferably, from the viewpoint of production efficiency, it is preferable to add a crosslinking agent to the ink receiving layer coating solution or the coating solution for forming the adjacent layer, and supply the crosslinking agent simultaneously with the formation of the ink receiving layer. In particular, it is preferably contained in the ink receiving layer coating solution from the viewpoint of improving the image printing density and glossiness. Further, the concentration of the crosslinking agent in the ink receiving layer coating solution is preferably 0.05 to 10% by mass, and more preferably 0.1 to 7% by mass.

For example, the crosslinking agent can be suitably applied as follows. Here, a boron compound will be described as an example. That is, when the ink receiving layer is a layer obtained by crosslinking and curing the coating layer coated with the ink receiving layer coating liquid (first coating liquid), the crosslinking curing is performed by (1) coating the coating layer by applying the coating liquid. (2) During the dry coating of the coating layer formed by coating the coating solution and before the coating layer exhibits a reduced rate of drying, the pH is 7.5. This is performed by applying the above basic solution (second coating solution) to the coating layer. The boron compound as the crosslinking agent may be contained in either the first coating liquid or the second coating liquid, or may be contained in both the first coating liquid and the second coating liquid.
It is preferable that the basic solution contains at least an ammonium salt. The ammonium salt is not particularly limited and various known ones can be used. For example, ammonium carbonate, ammonium zirconyl carbonate, ammonium hydrogen carbonate, ammonium phosphate, ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, ammonium chloride, Ammonia water is mentioned, and ammonium carbonate, zirconyl ammonium carbonate, and ammonium hydrogen carbonate are preferred from the viewpoint that no residual acid remains.

(mordant)
In the present invention, in order to improve the water resistance and aging resistance of the formed image, the ink receiving layer may further contain a mordant.
As the mordant, either an organic mordant or an inorganic mordant can be used. These mordants shall mean things other than the said water-soluble polyvalent metal salt compound and the said cationic polyurethane.

  The presence of the mordant in at least the upper layer of the ink receiving layer causes an interaction with an ink-jet liquid ink having an anionic dye as a coloring material, which stabilizes the coloring material, thereby improving water resistance and resistance. The aging blur can be further improved.

  In this case, the ink-receiving layer coating liquid (first coating liquid) and the basic solution (second coating liquid) may be contained, but the liquid containing the fine particles (especially gas phase method silica) Is preferably contained in a second coating liquid that is a separate liquid. That is, when a mordant is added directly to a coating solution for an ink receiving layer, aggregation may occur in the presence of vapor phase silica having an anionic charge. Can be prepared independently and applied separately, there is no need to worry about agglomeration of inorganic fine particles, and the range of mordant species can be selected.

  Among these, it is particularly preferable to use a basic mordant (for example, polyallylamine). When a basic mordant is used, it plays a role as a mordant and also functions as a basic substance, and a basic solution can be prepared without using a basic substance.

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.
Examples of the polymer mordant include a homopolymer of a monomer having a primary to tertiary amino group and a salt thereof, or a monomer having a quaternary ammonium base (hereinafter referred to as “mordant monomer”), or the mordant monomer. And those obtained as a copolymer or a condensation polymer of the other monomer (hereinafter referred to as “non-mordant polymer”) are preferable. These polymer mordants can be used in any form of a water-soluble polymer or water-dispersible latex particles.

  Examples of the 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-Np-vinylbenzyl Ammonium chloride, N, N-dimethyl-Nn-octyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-benzyl-Np-vinylbenzylammonium chloride, N, N-diethyl-N Benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N- (4-methyl) benzyl-Np-vinylbenzylammonium chloride, N, N-dimethyl-N-phenyl-Np-vinyl Benzylammonium 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- (acryloylua) C) ethylammonium chloride, triethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride, triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) Propylammonium 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.
Other examples of the copolymerizable monomer include N-vinylimidazole and N-vinyl-2-methylimidazole.

In addition, allylamine, diallylamine, derivatives thereof, salts and the like can also be used. Examples of such compounds include allylamine, allylamine hydrochloride, allylamine acetate, allylamine sulfate, diallylamine, diallylamine hydrochloride, diallylamine acetate, diallylamine sulfate, diallylmethylamine and salts thereof (for example, the salts include , Hydrochloride, acetate, sulfate, etc.), diallylethylamine and salts thereof (for example, hydrochloride, acetate, sulfate, etc.), diallyldimethylammonium salt (chloride as a counter anion of the salt, Acetate ion sulfate ion etc.). In addition, since these allylamines and diallylamine derivatives are inferior in polymerizability in the amine form, it is a general production method to polymerize in the form of a salt and desalting as required.
In addition, a polymerization unit such as N-vinylacetamide, N-vinylformamide or the like, which is converted into a vinylamine unit by hydrolysis after polymerization, and a salt thereof can be used.

The non-mordant monomer does not contain 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 interact with a dye in an inkjet ink. Or a monomer having a substantially small interaction.
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, vinyl propionate and vinyl versatic acid; Allyl esters such as allyl acetate Halogen-containing monomers such as vinylidene chloride and vinyl chloride; vinyl cyanide such as (meth) acrylonitrile; olefins such as ethylene and propylene; and the like.

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

  Further, as a polymer mordant, polydiallyldimethylammonium chloride, polymethacryloyloxyethyl-β-hydroxyethyldimethylammonium chloride, polyethylenimine, polyallylamine and its modified product, polyallylamine hydrochloride, polyamide-polyamine resin, cationized starch, Dicyandiamide formalin condensate, dimethyl-2-hydroxypropylammonium salt polymer, polyamidine, polyvinylamine, or acrylic silicon described in JP-A-10-264511, JP-A-2000-43409, JP-A-2000-343811, JP-A-2002-120452 Cationic acrylic emulsion of latex (trade name “Aquabrid series ASi-781, ASi-784, manufactured by Daicel Chemical Industries, Ltd.” ASi-578, ASi-903 ") and the like can also be mentioned as preferred, and polyallylamine and polyallylamine-modified products are particularly preferred.

  The polyallylamine-modified product is obtained by adding 2 to 50 mol% of acrylonitrile, chloromethylstyrene, TEMPO, epoxy hexane, sorbic acid or the like to polyallylamine, and preferably 5 to 5 of acrylonitrile, chloromethylstyrene, and TEMPO. It is a 10 mol% adduct, and 5 to 10 mol% TEMPO adduct of polyallylamine is particularly preferable from the viewpoint of exhibiting the effect of preventing ozone fading.

  The molecular weight of the mordant is preferably 2000 to 300,000 in terms of mass average molecular weight. When the molecular weight is within this range, the water resistance and aging resistance can be further improved.

(Other ingredients)
The ink receiving layer in the invention is constituted by containing the following components as required.
That is, for the purpose of suppressing the deterioration of the ink coloring material, various ultraviolet absorbers, antioxidants, anti-fading agents such as singlet oxygen quenchers may be included.
Examples of the ultraviolet absorber include cinnamic acid derivatives, benzophenone derivatives, benzotriazolylphenol derivatives, and the like. For example, α-cyano-phenyl cinnamate butyl, o-benzotriazole phenol, o-benzotriazole-p-chlorophenol, o-benzotriazole-2,4-di-t-butylphenol, o-benzotriazole-2,4 -Di-t-octylphenol etc. are mentioned. A hindered phenol compound can also be used as an ultraviolet absorber, and specifically, a phenol derivative in which one or more of at least 2-position or 6-position is substituted with a branched alkyl group is preferable.

  Moreover, a benzotriazole type ultraviolet absorber, a salicylic acid type ultraviolet absorber, a cyanoacrylate type ultraviolet absorber, an oxalic acid anilide type ultraviolet absorber, etc. can be used. For example, JP-A-47-10537, 58-111942, 58-21284, 59-19945, 59-46646, 59-109055, 63-53544. No. 36, Japanese Patent Publication No. 36-10466, No. 42-26187, No. 48-30492, No. 48-31255, No. 48-41572, No. 48-54965, No. 50-10726. No. 2,719,086, US Pat. No. 3,707,375, US Pat. No. 3,754,919, US Pat. No. 4,220,711, and the like. .

  A fluorescent brightening agent can also be used as an ultraviolet absorber, and examples thereof include a coumarin fluorescent brightening agent. Specifically, it is described in Japanese Patent Publication Nos. 45-4699 and 54-5324.

  Examples of the antioxidant include European Patent Publication No. 223739, Publication No. 309401, Publication No. 309402, Publication No. 310551, Publication No. 310552, Publication No. 4594416, Publication of German Patent No. 3435443, JP-A-54-48535, JP-A-60-107384, JP-A-60-107383, JP-A-60-125470, JP-A-60-125471, JP-A-60-125472, JP-A-60-287485. 60-287486, 60-287487, 60-287488, 61-160287, 61-185483, 61-2111079, 62-146678, 62-146680, 62-146679, 62-282885, JP same 62-262047, JP-same 63-051174, JP-same 63-89877, JP-same 63-88380, JP-same 66-88381, JP-same 63-113536 JP;

  JP-A-63-163351, JP-A-63-203372, JP-A-63-224989, JP-A-63-251282, JP-A-63-267594, JP-A-63-182484, JP-A-1-239282, JP-A-2-262654, JP-A-2-71262, JP-A-3-121449, JP-A-4-29185, JP-A-4-291684, JP-A-5-61166, JP-A-5-119449, 5-188687, 5-188686, 5-110490, 5-110437, 5-170361, JP 48-43295, 48-33212, Examples thereof include those described in U.S. Pat. Nos. 4,814,262 and 4,980,275.

  Specifically, 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2-dihydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2-dihydroquinoline 6-ethoxy-1-phenyl-2,2,4-trimethyl-1,2,3,4-tetrahydroquinoline, 6-ethoxy-1-octyl-2,2,4-trimethyl-1,2,3 4, -tetrahydroquinoline, nickel cyclohexane acid, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) -2-ethylhexane, 2-methyl-4-methoxy-diphenylamine, Examples include 1-methyl-2-phenylindole.

  These anti-fading agents may be used alone or in combination of two or more. The anti-fading agent may be water-solubilized, dispersed, emulsified, or contained in microcapsules. The addition amount of the anti-fading agent is preferably 0.01 to 10% by mass of the ink receiving layer coating solution.

  In the present invention, the ink receiving layer preferably contains a high boiling point organic solvent for curling prevention. The high-boiling organic solvent is preferably a water-soluble one. Examples of the water-soluble high-boiling organic solvent include ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, glycerin, diethylene glycol monobutyl ether (DEGMBE), Triethylene glycol monobutyl ether, glycerin monomethyl ether, 1,2,3-butanetriol, 1,2,4-butanetriol, 1,2,4-pentanetriol, 1,2,6-hexanetriol, thiodiglycol, Examples include alcohols such as triethanolamine and polyethylene glycol (weight average molecular weight of 400 or less). Diethylene glycol monobutyl ether (DEGMBE) is preferred.

The content of the high-boiling organic solvent in the ink-receiving layer coating solution is preferably 0.05 to 1% by mass, particularly preferably 0.1 to 0.6% by mass.
In addition, for the purpose of improving the dispersibility of the inorganic pigment fine particles, various inorganic salts, pH adjusting agents, and the like may contain acids and alkalis.
Further, for the purpose of suppressing surface frictional charge and peeling charge, the metal oxide fine particles having electronic conductivity may contain various matting agents for the purpose of reducing the surface frictional characteristics.

(Support)
The support in the present invention, a transparent support made of a transparent material such as plastic, may be used or an opaque support made of an opaque material such as paper. 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.
Further, an ink receiving layer can be provided on the label surface side using a read-only optical disc such as a CD-ROM or DVD-ROM, a write-once optical disc such as a CD-R or DVD-R, or a rewritable optical disc as a support. .

As a material that can be used for the transparent support, a material that is transparent and can withstand radiant heat when used in an OHP or a backlight display is preferable. Examples of such materials include polyesters such as polyethylene terephthalate (PET); polysulfone, polyphenylene oxide, polyimide, polycarbonate, polyamide, and the like. Of these, polyesters are preferable, and polyethylene terephthalate 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 of the ease of handling.

  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). Specifically, the following supports are mentioned.

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 suitable.

Although there is no restriction | limiting in particular also about the thickness of the said opaque support body, 50-300 micrometers is preferable at the point of the ease of handling.
In addition, it is preferable 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, a base paper used for a paper support such as resin-coated paper will be described.
The base paper is made from wood pulp as a main raw material and, if necessary, paper using synthetic pulp such as polypropylene or synthetic fibers such as nylon or polyester in addition to wood pulp. As the wood pulp, any of LBKP, LBSP, NBKP, NBSP, LDP, NDP, LUKP, and NUKP can be used, but it is preferable to use more LBKP, NBSP, LBSP, NDP, and LDP with a large amount of short fibers. preferable. However, the ratio of LBSP and / or LDP is preferably 10% by mass to 70% by mass.

As the above-mentioned pulp, chemical pulp (sulfate pulp or sulfite pulp) with few impurities is suitably used, and a pulp whose whiteness is improved by performing a bleaching treatment is also useful.
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 glycols A water retaining agent such as a dispersant, a softening agent such as a quaternary ammonium, and the like can be appropriately added.

  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. 30 to 70% of the sum with the mass% of is preferable. 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 calendering 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, a sizing agent similar to the size that can be added to the base paper can be used.
The pH of the base paper is preferably 5 to 9 when measured by a hot water extraction method defined in JIS P-8113.

  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 other LLDPE, polypropylene, etc. can also be used.

  In particular, the polyethylene layer on the side on which the ink receiving layer is formed is obtained by adding rutile or anatase type titanium oxide, fluorescent whitening agent, ultramarine blue to polyethylene, as is widely done in photographic paper, Those having improved whiteness and hue are preferred. Here, as a titanium oxide content, about 3-20 mass% is preferable with respect to polyethylene, and 4-13 mass% is more preferable. Although the thickness of a polyethylene layer does not have limitation in particular, 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. As the undercoat layer, aqueous polyester, gelatin and PVA are preferable. Moreover, as thickness of this undercoat layer, 0.01-5 micrometers is preferable.

  Polyethylene-coated paper can be used as glossy paper, or matte or silky surface that can be obtained with ordinary photographic printing paper by applying a so-called molding process when polyethylene is melt-extruded and coated on the base paper surface. Can also be used.

A back coat layer can be provided on the support, and examples of components that can be added to the back coat layer include a white pigment, an aqueous binder, and other components.
Examples of white pigments 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 aluminum silicate. , 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, white inorganic pigment, styrene And organic pigments such as polyethylene plastic pigments, acrylic plastic pigments, polyethylene, microcapsules, urea resins, and melamine resins.

Examples of the aqueous binder used in the backcoat layer include styrene / maleate copolymer, styrene / acrylate copolymer, polyvinyl alcohol, silanol-modified polyvinyl alcohol, starch, cationized starch, casein, gelatin, carboxy Examples thereof include water-soluble polymers such as methyl 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 backcoat layer include an antifoaming agent, an antifoaming agent, a dye, a fluorescent brightening agent, a preservative, and a water-proofing agent.

( Curl improvement method by production of inkjet recording medium)
The ink-receiving layer of the inkjet recording medium of the present invention, fine particles definitive at least the present invention on a support, a cationic polyurethane resin, a water-soluble resin, water-soluble polyvalent metal salt compound, and at least one sulfur-based organic matter and hydrazine derivatives It is an ink receiving layer formed by applying a coating liquid containing heel (first coating liquid) to form a coating layer and drying it .
Further, a crosslinking agent is added to the coating solution (first coating solution) and / or the following basic solution (second coating solution), and (1) the coating solution (first coating solution) is applied to form a coating layer. At the same time as forming, or (2) either during the drying of the coating layer formed by applying the coating solution (first coating solution) and before the coating layer exhibits a reduced rate of drying, By applying a basic solution (second coating solution) having a pH of 7.5 or more to the coating layer and crosslinking and curing the coating layer (this is referred to as “Wet on Wet method” or “WOW”). Preferably it is formed.

  The cross-linking agent capable of cross-linking the water-soluble resin is preferably contained in at least one or both of the first coating liquid and the second coating liquid. As described above, the ink receiving layer obtained by applying a basic solution (second coating solution) to the first coating solution at the same time as (1) or during (2) drying is crosslinked and cured. In addition to having advantages such as ink absorbability and prevention of film cracking, it is particularly preferable for improving the appearance of repelling failure and the like.

  Here, the aqueous dispersion of the self-emulsifying polymer of the present invention contained in the ink receiving layer is used by being added to at least one of the first coating liquid and the second coating liquid (basic solution). However, from the viewpoint of being sufficiently mixed with the fine particles and the water-soluble resin in the first coating liquid and effectively preventing aging blur over a long period of time, the aqueous dispersion of the self-emulsifiable polymer according to the present invention is the first coating. An embodiment in which it is contained in a liquid (a coating liquid containing fine particles and a water-soluble resin) is preferable. At this time, it is not always necessary to include the entire aqueous dispersion of the self-emulsifying polymer according to the present invention in the first coating liquid, but at least a part of the aqueous dispersion of the self-emulsifiable polymer according to the present invention. It is also effective to contain in the second coating liquid, and this can effectively prevent aging blurring. Also preferred is an embodiment in which at least a part of the aqueous dispersion of the self-emulsifying polymer according to the present invention is contained in both the first coating liquid and the second coating liquid.

  The mordant is preferably present so that the thickness of the portion where the mordant is present from the surface of the ink receiving layer is 10 to 60% with respect to the total thickness of the ink receiving layer. For example, (1) a method of forming a coating layer containing fine particles, a water-soluble resin and a crosslinking agent, and applying a mordant-containing solution thereon, (2) a coating solution containing the fine particles and a water-soluble resin, and a mordant-containing solution. It can be formed by any method such as a method of applying multiple layers. The mordant-containing solution may contain inorganic fine particles, a water-soluble resin, a crosslinking agent, and the like. When configured as described above, since a large amount of mordant is present in a required portion of the ink receiving layer, the ink color material of the ink jet is sufficiently mordanted, and the color density, aging blur, gloss of the printed portion, characters and images after printing are printed. It is preferable because water resistance and ozone resistance are further improved. Part of the mordant may be contained in the layer initially provided on the support, and in that case, the mordant to be applied later may be the same or different.

In the present invention, the coating liquid containing the inorganic pigment fine particles, the water-soluble resin, and the boron compound (crosslinking agent) as the first coating liquid can be prepared, for example, as follows.
That is, silica fine particles having an average primary particle size of 20 nm or less are added to water (for example, 10 to 20% by mass), and a high-speed rotating wet colloid mill (for example, “Clairemix” manufactured by M Technique Co., Ltd.) is used. For example, after being dispersed for 20 minutes (preferably 10 to 30 minutes) under the condition of high-speed rotation at a rotation speed of 10,000 rpm (preferably 5000 to 20000 rpm), a boron compound (for example, 0.5 to 20 of silica) (Mass%) and dispersion under the same conditions as above, an aqueous polyvinyl alcohol solution (for example, PVA having a mass of about 1/3 of silica), and further dispersion under the same rotation conditions as above. Can be prepared. The obtained coating solution is a uniform sol, and this is applied to a support by the following coating method to form an ink-receiving layer having a porous structure having a three-dimensional network structure.
If necessary, a pH adjuster, a dispersant, a surfactant, an antifoaming agent, an antistatic agent and the like can be further added to the first coating liquid.

  As the dispersing machine used for the above dispersion, various conventionally known dispersing machines such as a high-speed rotary dispersing machine, a medium stirring type dispersing machine (ball mill, sand mill, etc.), an ultrasonic dispersing machine, a colloid mill dispersing machine, and a high-pressure dispersing machine are used. However, in order to efficiently disperse the generated fine particles, a medium stirring type 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 used for preparation of each coating liquid. Examples of organic solvents that can be used in the coating solution 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. Can be mentioned.

  Moreover, the 2nd coating liquid (basic solution) containing surfactant can be prepared as follows, for example. That is, a mordant (for example, 0.1 to 5.0% by mass) and a surfactant (for example, a total amount of 0.01 to 1.0% by mass) in ion-exchanged water and a crosslinking agent (0 to 0 as necessary). 5.0% by mass) and sufficiently stirred. The pH of the second coating liquid is preferably 7.5 or more, and pH adjustment is carried out using ammonia water, sodium hydroxide, calcium hydroxide, amino group-containing compounds (ethylamine, ethanolamine, diethanolamine, polyallylamine, etc.) and the like. .5 or more can be appropriately performed.

  Application of the first coating liquid (ink receiving layer coating liquid) is, for example, a known coating such as an extrusion die coater, air doctor coater, bread coater, rod coater, knife coater, squeeze coater, reverse roll coater, bar coater, etc. It can be done by the method.

  At the same time as or after the application of the first coating liquid (ink-receiving layer coating liquid), the second coating liquid (basic solution) is applied to the coating layer. It may be applied before the coating layer exhibits reduced rate drying. That is, after the application liquid for the ink receiving layer is applied, it is preferably manufactured by introducing a basic solution while the applied layer exhibits constant rate drying. The second coating liquid may contain a mordant.

  Here, “before the coating layer comes to show reduced drying” usually refers to a process for several minutes immediately after the coating of the coating liquid for the ink-receiving layer. This shows a phenomenon of “constant rate drying” in which the content of the solvent (dispersion medium) of the ink decreases in proportion to time. The time indicating “constant rate drying” is described in, for example, “Chemical Engineering Handbook” (pages 707 to 712, published by Maruzen Co., Ltd., October 25, 1980).

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

  As a method of applying the second coating liquid before the reduced rate of drying is exhibited, (1) a method of further applying the second coating liquid on the coating layer, and (2) a method of spraying by a method such as spraying (3) A method of immersing the support on which the coating layer is formed in the second coating liquid.

  In the above method (1), examples of the application method for applying the second coating liquid include curtain flow coaters, extrusion die coaters, air doctor coaters, bread coaters, rod coaters, knife coaters, squeeze coaters, 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 first coating layer that has already been formed, such as an extrusion die coater, a curtain flow coater, or a bar coater.

The coating amount of the second coating solution, 5 to 50 g / m ² is generally, 10 to 30 g / m ² is preferred.

  After the application of the second coating liquid, it is generally heated at a temperature of 40 to 180 ° C. for 0.5 to 30 minutes, and dried and cured. Especially, it is preferable to heat at a temperature of 40 to 150 ° C. for 1 to 20 minutes. For example, when the cross-linking agent contained in the first coating liquid is borax or boric acid, heating at a temperature of 60 to 100 ° C. is preferably performed for 5 to 20 minutes.

  Further, when the basic solution (second coating solution) is applied simultaneously with the application of the ink receiving layer coating solution (first coating solution), the first coating solution supports the first coating solution and the second coating solution. The ink receiving layer can be formed by simultaneous application (multilayer application) on the support so as to come into contact with the body, followed by drying and curing.

  The simultaneous coating (multilayer coating) can be performed by a coating method using, for example, 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 are close to the discharge port of the extrusion die coater, that is, before moving onto the support. A multilayer is formed, and in that state, the multilayer is applied on the support. Since the two-layer coating liquid layered before coating is likely to cause a crosslinking reaction at the interface between the two liquids when transferred to the support, the two liquids to be discharged are mixed near the discharge port of the extrusion die coater. As a result, thickening is likely to occur, which may hinder the application operation. Therefore, when applying simultaneously as described above, it is preferable to apply a triple layer simultaneously with the application of the first coating liquid and the second coating liquid, with a barrier layer liquid (intermediate layer liquid) interposed between the two liquids. .

  The barrier layer solution can be selected without particular limitation. For example, an aqueous solution containing a trace amount of water-soluble resin, water, and 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. Here, the mordant may be contained in the barrier layer solution.

  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, the calendering process may cause a decrease in the porosity (that is, the ink absorbability may be decreased), so it is necessary to set the conditions under which the decrease in the porosity is small.

  As roll temperature in performing the said 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 inkjet recording, the thickness of the ink receiving layer in the present invention 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 ink jet recording, the layer thickness of the ink receiving layer is preferably 10 to 50 μm.
The pH of the film surface after drying of the ink jet recording medium having the ink receiving layer of the present invention is preferably 3 to 6.5, and from the viewpoint of storage stability, particularly discoloration to background yellowing, 3-6 Is preferably 0.0, and particularly preferably 3.7 to 5.5.

  The pore diameter of the ink receiving layer is preferably 0.005 to 0.030 μm, more preferably 0.01 to 0.025 μm in terms of median diameter. The porosity and pore median diameter can be measured using a mercury porosimeter “Bore Sizer 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. The haze value can be measured using a haze meter “HGM-2DP” manufactured by Suga Test Instruments Co., Ltd.

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

(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.) was added to a 4% aqueous solution of polyvinyl alcohol, and this was converted to 0 in terms of absolute dry weight. 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.

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 25 μm using a melt extruder to form a resin layer consisting of a mat surface. (Hereinafter, this 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 (“Snow manufactured by Nissan Chemical Industries, Ltd.”) are used. Tex O ") the mass ratio of 1: a dispersion dispersed in water at 2, dry weight 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) Low-density polyethylene containing MFR (melt flow rate) 3.8 is melt-extruded to a thickness of 23 μm using a melt extruder, and a high-gloss thermoplastic resin layer is formed on the surface side of the base paper. (Hereinafter, this highly glossy surface is referred to as “front side”), and used as a support for this example.

[Example 1]
(Preparation of coating solution for ink receiving layer)
(1) Silica fine particles, (2) Dispersant, and (3) ion-exchanged water in the following composition are mixed, and using a high-speed rotating colloid mill (“CLEARMIX” manufactured by M Technique Co., Ltd.) After being dispersed for 20 minutes at a rotational speed of 10,000 rpm, the following (4) boric acid (crosslinking agent), water-soluble resins (5) and (6), (7) diethylene glycol monobutyl ether, (8) and (9) Water-soluble polyvalent metal salt compound, (10) cationic urethane resin, (11) sulfur-based organic substance, and (12) surfactant are further dispersed under the same conditions as above, and the intended ink acceptance A layer coating solution was prepared.

<Composition of coating liquid for ink receiving layer>
(1) Fine particles: 100 parts (“Leosil QS-30” manufactured by Tokuyama Corporation, average primary particle size: 7 nm)
(2) Dispersant: 9.7 parts (“Sharol DC902P” manufactured by Daiichi Kogyo Seiyaku Co., Ltd., 51.5%)
(3) Ion-exchanged water ... 620.6 parts (4) Boric acid (cross-linking agent, 5.3%) ... 78.4 parts (5) Water-soluble resin (polyvinyl alcohol) ... 317.2 parts (( "PVA235" manufactured by Kuraray Co., Ltd., 7% aqueous solution)
(6) Water-soluble resin (water-soluble cellulose): 12.5 parts (“HPC-SSL”, 10% aqueous solution manufactured by Nippon Soda Co., Ltd.)
(7) Diethylene glycol monobutyl ether (100%) …… 3.6 parts (8) Water-soluble polyvalent metal salt compounds ………………………… 6.3 parts (first rare element) "Zircosol ZA-30", 30%, manufactured by Chemical Industry Co., Ltd.
(9) Water-soluble polyvalent metal salt compounds: 14 parts (“Alphain 83” manufactured by Daimei Chemical Industry Co., Ltd.)
(10) Cationic polyurethane resin ... 24.9 parts ("Superflex 600-B" manufactured by Daiichi Pharmaceutical Co., Ltd., 25%)
(11) Sulfur-based organic matter (3,6-dithio-1,8-octanediol)
............ 3.5 parts (12) Surfactant (polyoxyethylene oleyl ether) ............ 9.3 parts ("Emulgen 109P", 10%, manufactured by Kao Corporation)

(Preparation of inkjet recording sheet)
After the corona discharge treatment was applied to the front surface of the support, the ink receiving layer coating solution obtained above was applied to the front surface of the support at an application amount of 170 ml / m ² using an extrusion die coater. It was applied (application process), and dried with a hot air dryer at a temperature of 40 ° C. (wind speed 5 m / sec) until the solid content concentration of the application layer reached 18%. During this time, the coating layer exhibited a constant rate of drying. Immediately after that, it is immersed in a basic solution (pH = 9.6) having the following composition, and 20 g / m ² is deposited on the coating layer (solution application step), and further dried at a temperature of 80 ° C. for 10 minutes. (Drying process). As a result, an inkjet recording sheet of the present invention provided with an ink receiving layer having a dry film thickness of 35 μm was obtained.

<Composition of basic solution>
(1) Boric acid (crosslinking agent, 100%) ... 6.5 parts (2) Ion exchange water ... 832.5 parts (3) Basic chemicals (ammonium carbonate) ... 20.0 Part (4) Basic chemical (Zirconyl ammonium carbonate, 13%) ... 39.0 parts (5) Surfactant ... 100.0 parts ("Emulgen 109P" manufactured by Kao Corporation, 2%)
(6) Surfactant (Fluorine Surfactant) ............ 2.0 parts ("Megafac F-1405" manufactured by Dainippon Ink & Chemicals, 100%)

[Example 2]
In Example 1, 3.5 parts of a hydrazine compound (hydrazine compound (27) described in paragraph No. 0032 of JP-A-2002-337448) was newly added to <the composition of the coating solution for the ink-receiving layer>. The inkjet recording sheet of the present invention was obtained in the same manner as Example 1 except for the above.

[Example 3]
In Example 1, instead of 3.5 parts of (11) sulfur substance (3,6-dithio-1,8-octanediol) in <Composition of coating liquid for ink receiving layer>, 3.5 parts of guanylthiourea An inkjet recording sheet of the present invention was obtained in the same manner as in Example 1 except that was used.

[Example 4]
In Example 2, instead of 3.5 parts of (11) sulfur-containing compound (3,6-dithio-1,8-octanediol) in <Composition of coating liquid for ink-receiving layer>, a sulfur-containing compound (guanylthiourea) ) An ink jet recording sheet of the present invention was obtained in the same manner as in Example 2 except that 3.5 parts were used.

[Example 5]
In Example 2, except that 3.5 parts of (11) sulfur substance (3,6-dithio-1,8-octanediol) in <Composition of coating liquid for ink receiving layer> was not used. In the same manner as in No. 2, an inkjet recording sheet of the present invention was obtained.

[Comparative Example 1]
Example 1 is the same as Example 1 except that 3.5 parts of (11) sulfur substance (3,6-dithio-1,8-octanediol) in <Composition of coating liquid for ink receiving layer> was not used. In the same manner, an inkjet recording sheet of Comparative Example 1 was obtained.

[Comparative Example 2]
In Example 1, (8) water-soluble polyvalent metal salt compound (“Zircozol ZA-30”, 30%, manufactured by Daiichi Rare Element Chemical Co., Ltd.) in <Composition of coating liquid for ink receiving layer> and (11) An inkjet recording sheet of Comparative Example 2 was obtained in the same manner as in Example 1 except that the sulfur-based organic substance (3,6-dithio-1,8-octanediol) was not used.

[Comparative Example 3]
In Example 1, (9) Water-soluble polyvalent metal salt compound (“Alphain 83” manufactured by Daimei Chemical Co., Ltd.) and (11) Sulfur-based organic matter (<Composition of coating liquid for ink receiving layer>) An inkjet recording sheet of Comparative Example 3 was obtained in the same manner as in Example 1 except that 3,6-dithio-1,8-octanediol was not used.

[Comparative Example 4]
In Example 1, 24.9 parts of (10) cationic polyurethane resin (“Superflex 600-B”, 25%, manufactured by Daiichi Pharmaceutical Co., Ltd.) in <Composition of coating liquid for ink receiving layer> (11) An inkjet recording sheet of Comparative Example 4 was obtained in the same manner as in Example 1 except that the sulfur-based organic substance (3,6-dithio-1,8-octanediol) was not used.

[Comparative Example 5]
In Example 1, 12.5 parts of (6) water-soluble resin (water-soluble cellulose) (“HPC-SSL”, 10% aqueous solution manufactured by Nippon Soda Co., Ltd.) in <Composition of coating liquid for ink receiving layer> And (11) An inkjet recording sheet of Comparative Example 5 was obtained in the same manner as in Example 1 except that the sulfur-based organic substance (3,6-dithio-1,8-octanediol) was not used.

[Comparative Example 6]
In Example 1, 12.5 parts of (6) water-soluble resin (water-soluble cellulose) (“HPC-SSL”, 10% aqueous solution manufactured by Nippon Soda Co., Ltd.) in <Composition of coating liquid for ink receiving layer> , (8) 6.3 parts of a water-soluble polyvalent metal salt compound ("Zircozol ZA-30", 30%, manufactured by Daiichi Rare Element Chemical Co., Ltd.), (10) Cationic urethane resin (Daiichi Pharmaceutical Co., Ltd.) “Superflex 600-B” manufactured by Co., Ltd., 25%) 24.9 parts and (11) Sulfur-based organic matter (3,6-dithio-1,8-octanediol) was not used. In the same manner as in Example 1, an inkjet recording sheet of Comparative Example 6 was obtained.

(Evaluation test)
The following evaluation tests were performed on the ink jet recording sheets obtained from the above Examples and Comparative Examples. The results are shown in Table 1 below.
1) Curl Each inkjet recording sheet is cut into A6 size and left on a flat test plate for 1 hour in an environment of 10 ° C. and 30% RH, and the four corners of the inkjet recording sheet are raised from the test plate. Each height was measured, and the average of the heights was taken as the curl value. The curl value is not flat as the numerical value is large and the transportability is poor, and the curl value is flat as the value is small and the transportability is good. When the curl value is 7 mm or more, the practicality is lost.

2) Time Lapse Using an inkjet printer “BJF-900” manufactured by Canon Inc., magenta and yellow inks are adjacent to each inkjet recording sheet and a grid-like linear pattern (width 0.28 mm) is printed. did. The print sample is inserted into a transparent PP file and stored in an environment of 35 ° C. and 80% RH for 3 days. Then, the width of the linear magenta is measured, and the magenta line width increases with respect to the width immediately after printing. The rate (%) was calculated and used as an evaluation index for aging blur.
[Evaluation criteria]
○: When the increase rate is less than 15% ×: When the increase rate is 15% or more

3) Gas resistance Using an ink jet printer (“PM-900C” manufactured by Seiko Epson Corporation), a solid image of cyan was printed on each ink jet recording sheet, and in an environment with an ozone concentration of 2.5 ppm. Stored for 24 hours. The cyan density before and after storage was measured with a reflection density meter (“Xrite 938” manufactured by Xrite), the residual ratio of the cyan density was calculated, and evaluated according to the following evaluation criteria.
[Evaluation criteria]
◎: When the residual ratio is 85% or more ○: When the residual ratio is 70 or more and less than 85% ×: When the residual ratio is less than 70%

4) Beading Y (yellow), M (magenta), C (cyan), K (black), B (blue) on an inkjet recording sheet by an inkjet printer (PM-700C, manufactured by Seiko Epson Corporation) , G (green) and R (red) solid images were printed, and bead ball-shaped color unevenness was evaluated visually according to the following criteria.
[Standard]
○: No beading was observed.
○ ×: Slight occurrence of beading was observed.
Δ: Some beading was observed, but there was no practical problem.
X: Beading occurred.

  As shown in Table 1, it can be seen that in the examples, a flat ink jet recording sheet with little curling can be obtained without adversely affecting the quality such as aging blur and beading. On the other hand, in the comparative example, it can be seen that the curl is large.

Claims (12)

A method for improving curling of an ink jet recording medium having an ink-receiving layer on a support, comprising at least fine particles, a cationic polyurethane resin, a water-soluble resin, a water-soluble polyvalent metal salt compound, a sulfur organic compound and hydrazine on the support at least one preparative applied to a coating solution containing a to form a coating layer, curling improved method of ink jet recording medium and forming an ink-receiving layer formed by dry derivative. 2. The method for improving curling of an ink jet recording medium according to claim 1, wherein the cationic polyurethane resin is an aqueous dispersion. 2. The method for improving curling of an ink jet recording medium according to claim 1, wherein the water-soluble polyvalent metal salt compound is at least one selected from an aluminum compound, a zirconium compound and a titanium compound. The water-soluble resin is at least one selected from polyvinyl alcohol resins, cellulose resins, resins having an ether bond, resins having a carbamoyl group, resins having a carboxyl group, and gelatins. Karl improved method of ink jet recording medium according to claim 1. The method for improving curling of an ink jet recording medium according to claim 4, wherein the water-soluble resin contains a cellulose-based resin. The method for improving curling of an ink jet recording medium according to claim 4, wherein the water-soluble resin contains at least a polyvinyl alcohol resin having a saponification degree of 90% or less. 2. The method for improving curling of an ink jet recording medium according to claim 1, wherein the fine particles are at least one selected from silica fine particles, colloidal silica, alumina fine particles, and pseudoboehmite. The method for improving curling of an ink jet recording medium according to claim 1, wherein the ink receiving layer contains a crosslinking agent , and at least one of them is boric acid and a boric acid compound. 4. The method for improving curling of an ink jet recording medium according to claim 3, wherein at least two or more water-soluble polyvalent metal salt compounds are used in combination. The crosslinking agent is added to the coating solution and / or the following basic solution, and (1) the coating solution is applied to form a coating layer, or (2) the coating solution is applied. Crosslinking and curing is performed by applying a basic solution having a pH of 7.5 or more to the coating layer at any time during the drying of the coating layer and before the coating layer exhibits a reduced rate of drying. An ink jet recording medium according to any one of claims 1 to 9. The method for improving curling of an ink jet recording medium according to claim 10, wherein the basic solution contains at least an ammonium salt. Karl improved method of ink jet recording medium, wherein the surface pH of the ink jet recording medium in the claims 1 to 11 is 3 to 6.5.