JP4468870B2 - Recording medium and manufacturing method thereof - Google Patents

Description

  The present invention relates to a recording medium suitable for recording with ink, and particularly when applied to a printer or plotter using an ink jet recording system, has excellent ink absorbability, enables high-quality image recording, and long-term storage of images. The present invention relates to a recording medium in which image discoloration and image bleeding under high temperature and high humidity are suppressed, and a method for producing the same.

  In the inkjet recording method, ink droplets adhere to a recording medium such as paper by various operating principles, and at the same time, the solvent component of the ink penetrates into the recording medium or evaporates, so that the color material component is covered. This is a recording method that deposits on a recording medium and records images, characters, and the like (hereinafter simply referred to as “images”). In addition, the ink jet recording system is characterized in that it has excellent high-speed printability, low noise, and flexibility in recording patterns, can easily perform multi-coloring, and does not require development and image fixing.

  In particular, an image formed by a multicolor inkjet method can obtain a quality comparable to that of a multicolor printing by a plate making method or an image by a color photographic method, and is normal when the number of copies is small. In recent years, it has rapidly spread as an image recording apparatus for various information devices because it has an advantage that the printing cost is lower than that of the printing technique and the photographic technique. For example, it is widely applied to fields that require full-color image recording, such as image design output in the design industry, production of color blocks in the printing field where photographic image quality is required, signboards and sample products that are frequently replaced. is there. Recently, personal computers and digital still cameras have become widespread, and there are many opportunities to output photographic images using an inkjet printer even in general households.

  However, images recorded by inkjet printers are not suitable for long-term storage because they are markedly discolored and discolored by acid gases and light in the atmosphere compared to multicolor printing and color photographic images by the plate making method. It is. Therefore, there is a strong demand for preventing discoloration and discoloration of images, and many proposals have been made so far for improving the performance.

  For example, for the purpose of improving gas resistance, Patent Document 1 discloses a thioether compound, Patent Document 2 includes a hydrazide compound, Patent Document 3 and Patent Document 4 include a thiourea derivative, a thiosemicarbazide derivative, a thiocarbohydrazide derivative, and the like. There is disclosed a recording medium containing. In Patent Document 5, one kind from thiourea derivative, thiosemicarbazide derivative and thiocarbohydrazide derivative and one kind from iodine, iodide, dithiocarbamic acid, thiocyanate and thiocyanate are included. A recording medium is disclosed.

  As methods for improving light resistance, Patent Document 6, Patent Document 7 and Patent Document 8 disclose a recording medium containing a phenolic antioxidant, a benzophenone-based or a benzotriazole-based ultraviolet absorber. .

  Patent Document 9 proposes a recording medium containing a hindered amine compound, and Patent Document 10 proposes a recording medium containing a hydrazide compound.

  Further, in Patent Document 11 and Patent Document 12, ascorbic acid, erythorbic acid, or sodium erythorbate is contained in the ink receiving layer, and in Patent Document 13, Patent Document 14, and Patent Document 15, gas proof is obtained by containing a flavonoid in the ink receiving layer. A recording medium having improved properties and light resistance is disclosed.

  However, even if these conventional methods are used, a satisfactory effect is not always obtained. For example, compounds that are effective in gas resistance and light resistance, but not water-soluble, cannot be added to aqueous coating solutions, or even water-soluble compounds can be image-resistant under water resistance or high temperature and high humidity. Therefore, it is difficult to add an amount sufficient to improve the performance of the recording medium.

Japanese Patent Laid-Open No. 01-115677 Japanese Patent Laid-Open No. 61-154989 Japanese Patent Publication No. 04-034953 Japanese Patent Laid-Open No. 07-314883 Japanese Patent Laid-Open No. 08-025796 JP-A-57-074192 JP 57-087989 A Japanese Patent Laid-Open No. 60-072785 JP-A 61-146591 Japanese Patent Laid-Open No. 61-154989 Japanese Patent Laid-Open No. 07-195824 JP 08-150773 A JP 2001-071627 A JP 2001-139850 A JP 2001-301315 A

  The present invention has been made in view of the above-described actual circumstances, and has excellent ink absorbability when recording with a printer or plotter using an inkjet recording method, enables high-quality image recording, and long-term storage of images. It is an object of the present invention to provide a recording medium in which image discoloration due to acid gas or light in the atmosphere and bleeding of an image under high temperature and high humidity are effectively prevented.

  In order to obtain a recording medium suitable for long-term storage of images, the present inventors can effectively prevent discoloration of images due to acidic gas and light in the atmosphere and bleeding of images under high temperature and high humidity. As a result of repeated studies, it has been found that the above-mentioned problems can be solved by including a specific polymer compound, a specific organic acid and a specific polymer in the ink receiving layer, and the present invention has been completed.

That is, the present invention is, on at least one surface of a support, at least inorganic microparticles and at least one layer of the ink-receiving layer containing a polymer compound obtained by reacting a compound C with a compound B and compound A below In the recording medium provided , at least a part of the amino group of the polymer compound is phosphoric acid, phosphorous acid, formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, lactic acid, pyruvic acid, methanesulfonic acid, hydrochloric acid and A polymer compound cationized by at least one selected from nitric acid, and the ink receiving layer is further selected from hydroxy acid, alkylamine / epihalohydrin copolymer, dicyandiamide, allylamine, and acrylic polymer Contains at least one polymer, and the inorganic fine particles are dispersed by the polymer. Providing a recording medium characterized.
A: Sulfur-containing organic compound having two or more active hydrogen groups B: Polyisocyanate compound having two or more isocyanate groups
C: Amine compound having two or more active hydrogen groups
Hereinafter, a polymer compound obtained by reacting compound A and compound B is referred to as “first polymer compound”, and a polymer compound obtained by reacting compound A, compound B and compound C is referred to as It is called “second polymer compound”.

（式中、Ｒ¹、Ｒ²、Ｒ³はいずれか一つが炭素数１〜６のアルキル基、アルカノール基、またはアミノアルキル基であり、それ以外は同一もしくは異なっていてもよく、アルカノール基、アミノアルキル基、またはアルカンチオール基を表す。） In the recording medium of the present invention, before Symbol sulfur-containing organic compound A, it at least one containing a sulfide group in a molecule; and the amine compound C is represented by the following general formula (1) 3 A secondary amine is preferred.

(In the formula, any one of R ¹ , R ² , and R ³ is an alkyl group having 1 to 6 carbon atoms, an alkanol group, or an aminoalkyl group, and the others may be the same or different. Represents an aminoalkyl group or an alkanethiol group.)

In the recording medium of the present invention, the hydroxy acid, it is a monocarboxylic acid; Contact and the polymer is at least one polymer selected from the following formulas (2) to (5) Preferably there is.

（式中、Ｒ¹およびＲ²は、水素原子、炭素数１〜１８のアルキル基、ベンジル基を示す。Ｒ³、Ｒ⁴、Ｒ⁵は、水素原子、置換基を有してもよいアルキル基、アルケニル基、アルカノール基、アリルアルキル基、アリルアルケニル基を示す。またＲ¹、Ｒ²およびＲ³、Ｒ⁴、Ｒ⁵はそれぞれ同一であっても異なっていてもよい。Ｒ⁶は水素原子またはメチル基を表し、Ｒ⁷は枝分かれしていてもよい炭素数１〜１０のアルキレン基を表し、Ｒ⁸およびＲ⁹は互いに独立に炭素数１〜４のアルキル基を表し、Ｒ¹⁰は各々の炭素数が１〜８のアルキル基、アリールアルキル基または脂環アルキル基を表す。Ａは−ＣＯＯ−または−ＣＯＮＨ−を示す。Ｘ^-は、無機系、有機系の陰イオンを示す。ｎは重合度を示す整数である。）

(In the formula, R ¹ and R ² represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, and a benzyl group. R ³ , R ⁴ , and R ⁵ are a hydrogen atom and an alkyl that may have a substituent. Group, alkenyl group, alkanol group, allylalkyl group, allylalkenyl group, and R ¹ , R ² and R ³ , R ⁴ , R ⁵ may be the same or different, and R ⁶ is hydrogen. Represents an atom or a methyl group, R ⁷ represents an optionally branched alkylene group having 1 to 10 carbon atoms, R ⁸ and R ⁹ each independently represents an alkyl group having 1 to 4 carbon atoms, and R ¹⁰ represents Each represents an alkyl group having 1 to 8 carbon atoms, an arylalkyl group or an alicyclic alkyl group, A represents —COO— or —CONH—, and X ⁻ represents an inorganic or organic anion. n is an integer indicating the degree of polymerization.)

  Further, the present invention provides a method for producing a recording medium in which an ink receiving layer is provided by applying a coating liquid on at least one surface of a support, wherein the coating liquid comprises inorganic fine particles, hydroxy acid, A step of dispersing in a liquid medium together with at least one polymer selected from an alkylamine / epihalohydrin copolymer, a dicyandiamide, an allylamine, and an acrylic polymer to form a fine particle dispersion; Provided is a method for manufacturing a recording medium, which is prepared by adding a first and / or second polymer compound.

  In the production method of the present invention, the inorganic fine particles are alumina and / or alumina hydrate; and the polymer is at least one polymer selected from the general formulas (2) to (5). Preferably; and the hydroxy acid is a monocarboxylic acid.

  A recording medium suitable for long-term storage of an image, which effectively prevents discoloration of the image due to acidic gas or light in the atmosphere and bleeding of the image under high temperature and high humidity, by employing the above-described configuration of the present invention. Can be manufactured. In addition, according to the configuration of the present invention, a method for producing a recording medium capable of recording a high-quality image with excellent irritating odor (or unpleasant odor) generated when an organic acid is used and excellent ink absorbability is provided. it can.

  That is, by including the first and / or second polymer compound, the specific organic acid, and the specific polymer in the ink-receiving layer, the color of the image is changed and the image blurs under high temperature and high humidity. A suppressed recording medium could be manufactured. In the method for producing a recording medium, when forming the ink receiving layer, in addition to containing the first and / or second polymer compound, inorganic fine particles, a hydroxy acid, a specific acid, By using a fine particle dispersion containing a polymer, in addition to the above weather resistance, an irritating odor (or an unpleasant odor) is suppressed, and a recording medium capable of high-quality image recording with excellent ink absorbability is manufactured. We were able to.

Next, the present invention will be described in more detail with reference to preferred embodiments.
Examples of the support used in the present invention include, for example, appropriately sized paper, non-size paper, high-quality paper, medium-quality paper, coated paper, art paper, cast-coated paper, and one or both sides of the paper polyolefin. Made of paper such as resin-coated paper (hereinafter referred to as “resin-coated paper”) coated with the above resin; polyethylene, polypropylene, polyester, polylactic acid, polystyrene, polyacetate, polyvinyl chloride, cellulose acetate, polyethylene terephthalate Transparent thermoplastic resin films such as polymethyl methacrylate and polycarbonate; sheet-like substances made of films made opaque by filling with inorganic substances or fine foaming (synthetic paper, etc.); and sheets made of glass or metal, etc. Can be mentioned.
When using paper such as high-quality paper among the above supports, it is preferable to use those having a Steecht sizing degree of 15 seconds or more, more preferably 25 seconds or more, in order to obtain good color development and resolution.

  In addition, when the glossiness of the ink receiving layer formed on the support is enhanced and the image quality equivalent to that of a silver salt photograph is imparted, it is preferable to use a non-water-absorbing and highly smooth film and resin-coated paper. A support having at least a surface on which an ink receiving layer is formed has a 10-point average roughness of 0.5 μm or less according to JIS-B0601, and a 60-degree specular gloss according to JIS-Z-8741 is 25 to 75%. More preferably it can be used. Further, when a semi-gloss grade recording medium is obtained, it is preferable to use a film and resin-coated paper in which the surface on which the ink receiving layer is formed is matted or embossed.

Although there is no restriction | limiting in particular in the thickness of a support body, the range of 25 micrometers-500 micrometers is preferable, More preferably, it is the range of 50 micrometers-300 micrometers. When the thickness of the support is less than 25 μm, the rigidity is low, and inconveniences such as insufficient feel, texture or opacity when it is held in hand. On the other hand, when the thickness is larger than 500 μm, the obtained recording medium becomes rigid, which may hinder the paper feeding traveling of the printer. There is not any special restriction on the weight of the support is preferably within a range approximate ^{25g / m 2 ~500g / m 2} . In order to improve the adhesive strength between the support and the ink receiving layer, the surface of the support can be subjected to corona discharge treatment or various undercoat treatments.

  In the present invention, an ink-receiving layer containing the first and / or second polymer compound (having an effect of preventing discoloration and fading), a hydroxy acid, and a specific polymer on the support. By forming the recording medium, the recording medium of the present invention is obtained.

  Although it does not specifically limit as the compound A which is a raw material component of the said high molecular compound, The compound which has at least 1 or more sulfide group in a molecule | numerator is preferable, Specifically, following General formula (6)-(11) Mention may be made of the compounds represented. In addition, the following sulfur-containing organic compound A can be used alone or in combination of two or more thereof to synthesize the polymer compound of the present invention.

（式中ｎは１または２を表す。また、Ｒ¹はメチレン基、エチレン基、またはプロピレン基を表す。）

(In the formula, n represents 1 or 2. R ¹ represents a methylene group, an ethylene group, or a propylene group.)

（式中ｎは１または２を表す。また、Ｒ²およびＲ³はそれぞれ独立に水素原子、水酸基またはアルキル基を表し、Ｒ²およびＲ³は同一であっても異なっていてもよい。）

(In the formula, n represents 1 or 2. R ² and R ³ each independently represents a hydrogen atom, a hydroxyl group or an alkyl group, and R ² and R ³ may be the same or different.)

（式中ｎは０または１を表す。）

(Wherein n represents 0 or 1)

（式中ｎは１または２を表す。また、Ｒ⁴は硫黄原子または酸素原子を表し、Ｒ⁵は硫黄原子または−ＳＯ₂−を表し、Ｒ⁴およびＲ⁵は同一ではなく、それぞれ異なる基で構成される。）

(In the formula, n represents 1 or 2, R ⁴ represents a sulfur atom or an oxygen atom, R ⁵ represents a sulfur atom or —SO ₂ —, and R ⁴ and R ⁵ are not the same and are different groups. Composed of)

（式中Ｒ⁶およびＲ⁷はそれぞれ独立に水素原子またはアルキル基を表し、Ｒ⁶およびＲ⁷は同一であっても異なっていてもよい。）

(In the formula, R ⁶ and R ⁷ each independently represent a hydrogen atom or an alkyl group, and R ⁶ and R ⁷ may be the same or different.)

（式中Ｒ⁸は水酸基またはアルキル基を表す。）

(Wherein R ⁸ represents a hydroxyl group or an alkyl group.)

  Examples of the compound B which is a raw material component of the polymer compound used in the present invention include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4 ′. -Diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, 3,3'-dichloro-4,4'-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphthalene diisocyanate, tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethyle Diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, etc. Although it is mentioned, it is not limited to these. Moreover, it is possible to synthesize the polymer compound used in the present invention by using these polyisocyanate compounds alone or in combination of two or more.

  The first polymer compound used in the present invention is a reaction product of the compound A and the compound B. When the active hydrogen group is OH, for example, the compound A and the compound B are preferably reacted with each other at an equivalent ratio of OH / NCO of about 1. If the equivalent ratio of OH / NCO deviates significantly from 1, it is not preferable because the molecular weight of the resulting polymer compound does not increase. Preferred OH / NCO is in the range of 0.95 to 1.05. Further, in the reaction between the compound A and the compound B, a compound having two or more active hydrogen groups (hereinafter referred to as “compound D”) other than the compound A and the compound C described later may be used in combination. Although these compounds D will be described later, in this case as well, it is preferable to carry out the synthesis with an equivalent ratio of OH / NCO of all the reactants of around 1.

  In the first polymer compound obtained, the proportion of units derived from compound A in the polymer compound is preferably 10 to 70% by mass. More preferably, it is 30-70 mass%. When the content of the compound A unit is less than 10% by mass, a polymer compound having a sufficient image discoloration and fading preventing effect cannot be obtained. On the other hand, when the content of the compound A unit is more than 70% by mass, the resulting polymer compound becomes expensive, and it dissolves in the coating liquid when the ink receiving layer is formed using the polymer compound. In some cases, the properties and dispersibility are poor. The weight average molecular weight of the first polymer compound thus obtained is preferably in the range of 1,000 to 150,000 for the same reason as described below.

（式中Ｒ¹、Ｒ²、Ｒ³は前記と同意義である。） In the second polymer compound used in the present invention, at the time of the reaction between the compound A and the compound B, an amine compound C having two or more active hydrogen groups is further reacted, and the compound is obtained in the resulting polymer compound. It is preferred to incorporate a C unit and cationize at least a portion of the amino group in the unit. The compound C is preferably a tertiary amine represented by the following general formula (1).

(Wherein R ¹ , R ² and R ³ are as defined above.)

  Specific examples of the compound represented by the general formula (1) include, for example, N-methyl-N, N-diethanolamine, N-ethyl-N, N-diethanolamine, N-isobutyl-N, N— as diol compounds. Examples include diethanolamine, N-tert-butyl-N, N-diethanolamine, N-tert-butyl-N, N-diisopropanolamine, and examples of the triol compound include triethanolamine. Examples of the diamine compound include methyliminobispropylamine and butyliminobispropylamine, and examples of the triamine compound include tri (2-aminoethyl) amine. These amine compounds can be used alone or in combination of two or more to synthesize the second polymer compound used in the present invention.

  As described above, the second polymer compound used in the present invention is obtained by reacting compound A, compound B and compound C, and compound A unit, compound B unit and compound C unit (the tertiary amino group in the unit is a cation). Is obtained as a polymer compound containing in the molecule. In order to fully express the function of the polymer compound, the content of compound C in the polymer is preferably 5.5 to 18.5% in terms of molar ratio. If the content of Compound C is lower than 5.5% in terms of molar ratio, the content of hydrophilic groups will decrease, which may be inconvenient when preparing an aqueous dispersion of the polymer compound, In some cases, it may be difficult to blend into the aqueous coating solution. On the other hand, when the content of Compound C is higher than 18.5% in terms of molar ratio, there may be a problem that glossiness and print density are lowered in a recording medium containing the polymer compound.

  In the second polymer compound used in the present invention, if the molar ratio of compound C is in the above range, the compound C unit can occupy 3 to 80% by mass in the polymer compound. Exceeding this range may cause problems such as a decrease in water dispersibility as described above and a decrease in glossiness and print density.

  In the second polymer compound used in the present invention, if the content of compound C is in the above range, the mass of the compound A unit incorporated in the polymer compound is 10 to 65 in the polymer compound. It is preferable to occupy% by mass. More preferably, it is the ratio which occupies 30-65 mass%. If the proportion of the compound A unit is less than 10% by mass, the effect of preventing discoloration and fading of the image may be insufficient. On the other hand, when the proportion of the compound A unit exceeds 65% by mass, the content of the hydrophilic group is relatively lowered, which may be inconvenient when preparing an aqueous dispersion of the polymer compound.

  Compound B has a function of linking compound A and compound C, and the amount of compound B used is not particularly limited. However, if the content of compound C is in the above range, the mass of compound B unit is obtained. It is preferable to occupy 10 to 80% by mass in the obtained polymer compound. More preferably, it is the ratio which occupies 30-60 mass%. When the proportion of the compound B unit is within this range, an amount sufficient to fully exhibit the functions of the compound A unit and the compound C unit can be combined.

  The method for producing the second polymer compound using the compounds A to C may be a so-called one-shot method in which the compounds A to C are reacted at once to form a random polymer, or the compound A (or the compound A A so-called prepolymer method is used in which a prepolymer having a terminal isocyanate group is produced by reacting C) with compound B in a proportion rich in isocyanate groups and reacting the prepolymer with compound C (or compound A). May be. In any method, a chain extender such as a low molecular weight polyol or a low molecular weight diamine may be used in combination. In addition, the molecular weight of the resulting polymer compound can be adjusted by changing the amount of compounds A to C used or adding a reaction terminator such as monoalcohol or monoamine to the reaction system at an appropriate timing.

  The weight average molecular weight of the first or second polymer compound thus obtained is preferably in the range of 1,000 to 150,000, preferably in the range of 2,000 to 50,000, although it depends on the reaction conditions. Is more preferable. If the weight average molecular weight of the polymer compound is less than 1,000, the glossiness and printing density may be lowered. If it exceeds 150,000, the reaction time becomes longer and the production cost increases, which is not preferable.

  Moreover, when manufacturing the 1st or 2nd high molecular compound used by this invention, you may copolymerize the compound D other than the said compound A and the compound C as needed. As such compound D, it is also possible to synthesize the polymer compound used in the present invention by using the following polyester polyol, polyether polyol, or polycarbonate polyol alone or in combination of two or more. .

  Examples of the polyester polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, and 1,6-hexane. Diol, neopentyl glycol diol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol having a molecular weight of 300 to 1,000, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanedimethanol, Glycol components such as bisphenol A, bisphenol S, hydrogenated bisphenol A, hydroquinone, alkylene oxide adducts, malonic acid, succinic acid, glutaric acid, adipine , Pimelic acid, suberic acid, azelaic acid, sebacic acid, hedecane dicarboxylic acid, decanedicarboxylic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bisphenoxyethane-p, p'-dicarboxylic acid, dicarboxylic acid Polyesters obtained by a ring-opening polymerization reaction of cyclic ester compounds such as ε-caprolactone, including polyesters obtained by dehydration condensation reaction from acid components such as anhydrides or ester-forming derivatives of These copolyesters are listed. I can get lost.

  Examples of the polyether polyol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexane. Diol, neopentyl glycol, glycerin, trimethylol ethane, trimethylol propane, sorbitol, sucrose, bisphenol A, bisphenol S, hydrogenated bisphenol A, aconitic acid, trimellitic acid, hemimellitic acid, phosphoric acid, ethylenediamine, diethylenetriamine, triisopropanol Compound having at least two active hydrogens such as amine, pyrogallol, dihydroxybenzoic acid, hydroxyphthalic acid, 1,2,3-propanetrithiol The product obtained by subjecting a product to addition polymerization by a conventional method using one or more monomers such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene as an initiator. It is done. As other polyether polyols, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran using a compound having at least two primary amino groups such as ethylenediamine and propylenediamine as an initiator. In addition, one obtained by subjecting one or more monomers such as cyclohexylene to addition polymerization by a conventional method can also be used.

  Examples of the polycarbonate polyol include compounds obtained by reacting glycols such as 1,4-butanediol, 1,6-hexanediol, diethylene glycol and the like with diphenyl carbonate and phosgene.

  In the synthesis of the first or second polymer compound used in the present invention, it is desirable to use a tin-based catalyst and / or an amine-based catalyst in the isocyanate polyaddition reaction. Examples of the tin-based catalyst include dibutyltin dilaurate and stannous octoate. Examples of the amine-based catalyst include triethylenediamine, triethylamine, tetramethylpropanediamine, tetramethylbutanediamine, and N-methylmorpholine. It is not limited to.

  The above-mentioned isocyanate polyaddition reaction can be carried out in the absence of a solvent depending on the composition, but a hydrophilic organic solvent that does not directly participate in the isocyanate polyaddition reaction system is reacted for the purpose of controlling the reaction system or controlling the base viscosity. It is common to use as a solvent. Examples of such hydrophilic organic solvents include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate. And organic acid esters such as methyl propionate, ethyl propionate and butyl propionate, and amines such as N, N-dimethylformamide and N-methylpyrrolidone. Moreover, it is preferable that the used hydrophilic organic solvent is finally removed.

  In the second polymer compound used in the present invention, at least part of the tertiary amino group of the compound C unit contained therein is cationized with an acid or a quaternizing agent before or after the synthesis of the polymer compound. And can be dispersed or dissolved in water. In order to disperse or dissolve the second polymer compound in water at a preferred particle size described later, it is preferable to cationize with an acid, and it is more preferable to use phosphoric acid or a monovalent acid as the acid. preferable. Examples of phosphoric acid include phosphoric acid and phosphorous acid. Examples of the monovalent acid include organic acids such as formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, lactic acid, pyruvic acid, and methanesulfonic acid, and inorganic acids such as hydrochloric acid and nitric acid. The reason why these acids are preferable is that the second polymer compound cationized with a polyvalent acid other than phosphoric acid may cause thickening when dispersed or dissolved in water. is there. In addition, the second polymer compound cationized with a hydroxy acid such as glycolic acid or lactic acid, when applied to a recording medium, has a blank portion compared to the second polymer compound cationized with another acid. Since there exists an effect which suppresses yellowing, it can use more preferably.

  Among the second polymer compounds used in the present invention obtained by the method as described above, those particularly preferred are represented by the following general formulas (12) to (17).

（式中ｎは１または２を、Ｒ₁はメチレン基、エチレン基、またはプロピレン基を、Ｒ₉はアルキレン基もしくは複脂環を１つ以上含む脂肪族炭化水素基を、Ｒ₁₀は炭素数１〜４のアルキル基を、Ｒ₁₁およびＲ₁₂はそれぞれ独立で水素原子もしくはメチル基を、Ｘ^-は酸陰イオンを表す。ｍは重量平均分子量が１，０００〜１５０，０００になる数である。）

(Wherein n is 1 or 2, R ₁ is a methylene group, ethylene group or propylene group, R ₉ is an aliphatic hydrocarbon group containing one or more alkylene groups or double alicyclic rings, and R ₁₀ is the number of carbon atoms. 1 to 4 alkyl groups, R ₁₁ and R ₁₂ each independently represents a hydrogen atom or a methyl group, X ⁻ represents an acid anion, and m is a number having a weight average molecular weight of 1,000 to 150,000. is there.)

（式中ｎは１または２を、Ｒ₂およびＲ₃はそれぞれ独立で水素原子、水酸基またはアルキル基を、Ｒ₂およびＲ₃は同一であっても異なっていてもよい。尚、Ｒ₉〜₁₂およびＸ^-およびｍは一般式（１２）と同義である。）

(A wherein n is 1 or 2, R ₂ and R ₃ are independently a hydrogen atom, a hydroxyl group or an alkyl group, R ₂ and R ₃ may be be the same or different. In addition, R ₉ ~ ₁₂ and X ^- and m have the same meaning as in formula (12).)

（式中ｎは０または１を表す。Ｒ₉〜₁₂およびＸ^-およびｍは一般式（１２）と同義である。）

(In the formula, n represents 0 or 1. R ₉ to ₁₂ and X ⁻ and m have the same meaning as in the general formula (12).)

（式中ｎは１または２を、Ｒ₄は硫黄原子または酸素原子を、Ｒ₅は硫黄原子または−ＳＯ₂−、Ｒ₄およびＲ₅は同一ではなく、それぞれ異なる基で構成される。尚、Ｒ₉〜₁₂およびＸ^-およびｍは一般式（１２）と同義である。）

(In the formula, n is 1 or 2, R ₄ is a sulfur atom or an oxygen atom, R ₅ is a sulfur atom or —SO ₂ —, R ₄ and R ₅ are not the same, and each is composed of a different group. , R ₉ to ₁₂ and X ⁻ and m have the same meanings as those in the general formula (12).

（式中Ｒ₆およびＲ₇はそれぞれ独立で水素原子またはアルキル基を表し、Ｒ₆およびＲ₇は同一であっても異なっていてもよい。尚、Ｒ₉〜₁₂およびＸ^-およびｍは一般式（１２）と同義である。）

(In the formula, R ₆ and R ₇ each independently represent a hydrogen atom or an alkyl group, and R ₆ and R ₇ may be the same or different. R ₉ to ₁₂ and X ⁻ and m are (It is synonymous with Formula (12).)

（式中Ｒ₈は水酸基またはアルキル基を表す。尚、Ｒ₉〜₁₂およびＸ^-およびｍは一般式（１２）と同義である。）

(In the formula, R ₈ represents a hydroxyl group or an alkyl group. R ₉ to ₁₂ and X ⁻ and m have the same meanings as in the general formula (12).)

  When the second polymer compound used in the present invention is dispersed in an aqueous medium, the average particle size of the dispersion is preferably in the range of 5 nm to 500 nm from the viewpoint of storage stability. In addition, the average particle diameter as used in the present invention is measured by a dynamic light scattering method, and is described in “Structure of polymer (2) Scattering experiment and morphology observation Chapter 1 light scattering” (Kyoritsu Shuppan Polymer Society). Chem. Phys. , 70 (B), 15 ApI. 3965 (1979). The average particle size defined in the present invention can be easily measured using, for example, a laser particle size analyzer PARIII (manufactured by Otsuka Electronics Co., Ltd.) or the like.

  In the recording medium of the present invention, the ink receiving layer has the above first and / or second polymer compound (hereinafter sometimes simply referred to as “polymer compound”), a hydroxy acid described later, and an alkylamine / epihalohydrin. And at least one polymer selected from a series copolymer, a dicyandiamide, an allylamine, and an acrylic polymer (hereinafter sometimes referred to simply as “polymer”). The ink-receiving layer is formed by coating a surface of a suitable support in which other additives such as the above polymer compound, hydroxy acid, polymer, suitable binder, and suitable inorganic fine particles are dispersed and dissolved in an aqueous solvent. An ink receiving layer is formed by a method of applying and drying a working solution, or a coating solution not containing a polymer compound, and then the polymer compound in the ink receiving layer by an appropriate method such as an overcoat method. It is carried out by a method of impregnating in the liquid. A particularly preferred method is the step of dispersing the inorganic fine particles, the hydroxy acid, and the polymer together in a liquid medium as the coating liquid to obtain a fine particle dispersion, and at least the first and / or the fine particle dispersion. In this method, the coating solution prepared by the step of adding the second polymer compound is used.

  The content of the polymer compound used in the present invention is preferably 0.05 to 20% by mass in terms of solid content with respect to the ink receiving layer. If the content is within this range, it is possible to effectively prevent discoloration and discoloration of the image due to gas and light in the atmosphere and image bleeding under high temperature and high humidity. If the content with respect to the ink receiving layer is less than 0.05% by mass, it is not possible to sufficiently prevent discoloration or discoloration of the image due to gas or light, which is the object of the present invention. There is a risk of deterioration in absorbability and a decrease in print density.

  In the present invention, a recording medium exhibiting further excellent gas resistance and light resistance can be obtained by adding a hydroxy acid together with the polymer compound to the ink receiving layer.

  The hydroxy acid used in the present invention is a compound having a carboxyl group (—COOH) and an alcoholic hydroxyl group (—OH) in one molecule, and is also called an oxyacid. Examples of such compounds include monocarboxylic acids such as glycolic acid, lactic acid, 2-hydroxyisobutyric acid, and 2-ethyl-2-hydroxybutyric acid, and polyvalent carboxylic acids such as malic acid, tartaric acid, and citric acid. These can be used alone or in combination.

  The use amount of the hydroxy acid is preferably 0.01% by mass to 10% by mass with respect to the ink receiving layer for the purpose of improving the gas resistance and light resistance of the image. When the amount used is less than 0.01% by mass, the synergistic effect when used in combination with the polymer compound is not sufficiently exhibited. On the contrary, when the amount used exceeds 10% by mass, the bleeding of the image is deteriorated under high temperature and high humidity, or the ink absorbability is lowered and beading (a phenomenon in which the ink cannot absorb the ink and becomes a granular density unevenness). ) Occurs.

  In the recording medium of the present invention, inorganic fine particles may be further added to the ink receiving layer. However, the inorganic fine particles used at that time have high ink absorbability, excellent color development, and high-quality images. Fine particles that can be formed are preferred. Examples of such inorganic fine particles include calcium carbonate, magnesium carbonate, kaolin, clay, talc, hydrotalcite, aluminum silicate, calcium silicate, magnesium silicate, diatomaceous earth, alumina, colloidal alumina, aluminum hydroxide, and alumina hydrate. Products, synthetic amorphous silica, colloidal silica, lithopone, zeolite and the like, and these can be used alone or in combination of two or more.

  As the form of the inorganic fine particles, in order to obtain a highly glossy and highly transparent ink-receiving layer, the average particle diameter is preferably in the range of 50 nm to 500 nm, more preferably in the range of 100 nm to 300 nm. When the average particle size of the inorganic fine particles is smaller than 50 nm, the ink absorbability of the ink receiving layer is remarkably lowered, and ink bleeding or beading occurs when printing is performed with a printer having a large discharge amount. On the other hand, when the average particle size is larger than 500 nm, the transparency of the ink receiving layer is lowered, and the print density and gloss of the image may be lowered. The average particle diameter as used in the present invention is measured by a dynamic light scattering method, and “polymer structure (2) scattering experiment and morphology observation Chapter 1 light scattering (edited by Kyoritsu Publishing Society of Polymer Science)” or “J Chem. Phys., 70 (B), 15 Appl., 3965 (1979) ”.

The BET specific surface area of the inorganic fine particles is preferably in the range of 50 to 500 m ² / g, more preferably in the range of 50 to 250 m ² / g. When the BET specific surface area is in the range of 50 to 250 m ² / g, the ink absorbability, beading, smoothness and the like are excellent. On the other hand, when the BET specific surface area is less than 50 m ² / g, the transparency of the ink receiving layer and the image density are lowered, and the printed matter tends to be white and dull, and the BET specific surface area is low. If it exceeds 500 m ² / g, the ink absorptivity decreases, and a large amount of acid is required as a peptizer to stably disperse the alumina hydrate, which is not preferable.

  In the present invention, among the above-described inorganic fine particles, alumina fine particles such as alumina and alumina hydrate can be preferably used, and the ink receiving layer to be formed is excellent in transparency and smoothness, and has finer voids. In view of the ability to form hydrated alumina, a hydrated alumina having a boehmite structure or a pseudoboehmite structure can be used more preferably.

式中、ｎは０、１、２または３の整数の内、いずれかを表し、ｍは０〜１０、好ましくは０〜５の値を表す。ｍＨ₂Ｏは多くの場合、結晶格子の形成に関与しない脱離可能な水相を表すものであるため、ｍは整数でない値をとることができる。また、この種のアルミナ水和物をか焼した場合、ｍは０の値に達することがあり得る。 The alumina hydrate used in the present invention is defined by the following general formula (18).

In the formula, n represents any one of integers of 0, 1, 2, or 3, and m represents a value of 0 to 10, preferably 0 to 5. In many cases, mH ₂ O represents a detachable aqueous phase that does not participate in the formation of a crystal lattice, and therefore m can take a non-integer value. Also, when this type of alumina hydrate is calcined, m can reach a value of zero.

  In general, an alumina hydrate crystal having a boehmite structure is a layered compound having a (020) plane forming a giant plane, and exhibits a diffraction peak peculiar to an X-ray diffraction pattern. As the boehmite structure, in addition to perfect boehmite, a structure called excess boehmite and containing excess water between layers of the (020) plane can be taken. The X-ray diffraction pattern of this pseudoboehmite shows a broader diffraction peak than that of perfect boehmite. Since complete boehmite and pseudoboehmite are not clearly distinguishable, unless otherwise specified, they are both referred to as alumina hydrate showing a boehmite structure.

  Although it does not specifically limit as a manufacturing method of an alumina hydrate, For example, any methods, such as a buyer method and an alum pyrolysis method, are employable. A particularly preferable method is a method in which an acid is added to a long-chain aluminum alkoxide for hydrolysis. Moreover, the obtained alumina hydrate can be controlled to a specific range of the particle shape of the alumina hydrate by adjusting the conditions of the aging process for growing particles through the hydrothermal synthesis process, When the aging time is appropriately set, primary particles of alumina hydrate having a relatively uniform particle size grow. The sol obtained here can be used as a dispersion by adding an acid as a peptizer, but in order to further improve the dispersibility of alumina hydrate in water, the sol is spray-dried, etc. After pulverizing by this method, an acid can be added to form a dispersion.

  In the present invention, when the inorganic fine particles (alumina hydrate) are added to the ink receiving layer, it is preferable to prepare in advance a fine particle dispersion in which the inorganic fine particles are dispersed in an aqueous solvent. Inorganic fine particles are generally easily peptized by using a large amount of acid as a peptizer and can be a uniform dispersion. However, inorganic acids are highly corrosive to metals and are not preferable for equipment safety. In addition, although organic acids are relatively less problematic in terms of chemical safety and corrosiveness, they have a higher boiling point than inorganic acids, especially when a low heat resistant material such as paper or film coated with a resin is used as a support. Since the ink cannot be dried at a high temperature, an acid remains in the ink receiving layer, which causes generation of an irritating odor (or unpleasant odor). Furthermore, when the concentration of the acid remaining in the ink receiving layer increases, the pH of the ink receiving layer itself decreases, and beading may occur, resulting in a marked decrease in image quality, which is not ideal.

  Instead of using acid as a deflocculant, the above problems can be avoided by making dispersions using various surfactants or polymer dispersants. Bubbles are generated in the liquid, which may cause coating defects. In addition, when a polymeric dispersant is used, a relatively strong shearing force and a long period of stirring are required to peptize the alumina hydrate to primary particles, and a uniform dispersion without aggregates. It is difficult to obtain a high quality ink receiving layer.

  Therefore, in the present invention, it is preferable to produce a fine particle dispersion by using an organic acid and a polymer described later in combination and dispersing and peptizing inorganic fine particles in an aqueous solvent. Thereby, even if the usage-amount of organic acid is reduced, the low-viscosity and fully peptized fine particle dispersion can be prepared. In addition, by using hydroxy acid as an organic acid having a relatively high boiling point and no unpleasant odor, the odor generated from the ink receiving layer is suppressed, and furthermore, the acid concentration in the ink receiving layer is suppressed low. It is possible to form an ink receiving layer in which beading is suppressed.

  As described above, monocarboxylic acids and polyvalent carboxylic acids exist in hydroxy acids. When hydroxy acids composed of polyvalent carboxylic acids are used as a peptizer for inorganic fine particles (alumina hydrate), Since the viscosity increases, it is preferable to use a hydroxy acid composed of a monocarboxylic acid.

  The amount of hydroxy acid used in the fine particle dispersion varies depending on the amount of inorganic fine particles used, the particle size, and the specific surface area, but may be any minimum amount necessary for peptizing fine particles in a water-soluble solvent. Preferably it is 0.1-10 mass% with respect to microparticles | fine-particles, More preferably, the range of 0.5-5 mass% is desirable. When the amount used is less than 0.1% by mass, the viscosity of the dispersion may increase with time, which is not preferable. Conversely, when the amount used exceeds 10% by mass, the dispersion effect does not increase any more, the image bleeding under high temperature and high humidity deteriorates, or the ink absorbability decreases and beading occurs. Cause problems. In the present invention, a known organic acid or inorganic acid peptizer such as acetic acid, formic acid, nitric acid and hydrochloric acid may be used in combination with hydroxy acid as long as the effects of the present invention are not impaired.

式中、Ｒ¹およびＲ²は、水素原子、炭素数１〜１８のアルキル基、ベンジル基、シクロヘキサン環を有する１級または２級脂環式アミン残基を示す。Ｒ³、Ｒ⁴およびＲ⁵は、水素原子、置換基を有してもよいアルキル基、アルケニル基、アルカノール基、アリルアルキル基、アリルアルケニル基を示す。またＲ¹、Ｒ²およびＲ³、Ｒ⁴、Ｒ⁵はそれぞれ同一であっても異なっていてもよい。Ｒ⁶は水素原子またはメチル基を表し、Ｒ⁷は枝分かれしていてもよい炭素数１〜１０のアルキレン基を表し、Ｒ⁸およびＲ⁹は互いに独立に炭素数１〜４のアルキル基を表し、Ｒ¹⁰は各々の炭素数が１〜８のアルキル基、アリールアルキル基または脂環アルキル基を表す。Ａは−ＣＯＯ−または−ＣＯＮＨ−を示す。Ｘ^-は、無機系、有機系の陰イオンである。これらは、特に限定されるものではないが、例えば、無機系陰イオンとしては、Ｃｌ^-、Ｂｒ^-、Ｉ^-、硝酸イオン、亜硝酸イオン、燐酸イオン、硫酸イオン、有機系陰イオンとしては、スルホン酸アニオン、アルキルスルホン酸アニオン、アルキルカルボン酸アニオンや、蟻酸、酢酸、グリコール酸、グルコン酸、乳酸などの有機酸由来の陰イオンを表す。ｎは重合度を示す整数である。 The alkylamine / epihalohydrin-based copolymer, dicyandiamide-based, allylamine-based, and acrylic-based polymer used in the present invention are polymers represented by the following general formulas (2) to (5), each of which is used singly or in combination. can do.

In the formula, R ¹ and R ² represent a primary or secondary alicyclic amine residue having a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, a benzyl group, or a cyclohexane ring. R ³ , R ⁴ and R ⁵ represent a hydrogen atom, an alkyl group which may have a substituent, an alkenyl group, an alkanol group, an allylalkyl group or an allylalkenyl group. R ¹ , R ² and R ³ , R ⁴ , R ⁵ may be the same or different. R ⁶ represents a hydrogen atom or a methyl group, R ⁷ represents an optionally branched alkylene group having 1 to 10 carbon atoms, R ⁸ and R ⁹ each independently represents an alkyl group having 1 to 4 carbon atoms. , R ¹⁰ represents an alkyl group having 1 to 8 carbon atoms, an arylalkyl group or an alicyclic alkyl group. A represents —COO— or —CONH—. X ⁻ is an inorganic or organic anion. Although these are not particularly limited, for example, as inorganic anions, Cl ⁻ , Br ⁻ , I ⁻ , nitrate ions, nitrite ions, phosphate ions, sulfate ions, and organic anions include A sulfonate anion, an alkyl sulfonate anion, an alkyl carboxylate anion, and an anion derived from an organic acid such as formic acid, acetic acid, glycolic acid, gluconic acid, and lactic acid. n is an integer indicating the degree of polymerization.

  The weight average molecular weight of the polymer represented by the general formulas (2) to (5) is not particularly limited, but is preferably in the range of 1,000 to 200,000, more preferably 1,000 to 100,000. More preferably, the range of 1,000 to 50,000 is desirable. When the weight average molecular weight is low, bubbles are likely to be generated, which may cause coating defects. Moreover, since the viscosity of a coating liquid may become high when a weight average molecular weight is high, it is unpreferable.

  The amount of the polymer used depends on the amount of the hydroxy acid used in combination, but when used in a large amount, the viscosity of the fine particle dispersion and the coating liquid obtained by adding a binder to the dispersion increase, and the liquid itself is preserved. It is preferable to add a trace amount as much as possible because the properties and coating suitability are lowered. Therefore, the amount of the polymer used in the fine particle dispersion of the present invention is preferably 0.01 to 5% by mass, more preferably 0.01 to 3% by mass with respect to the inorganic fine particles.

  The aqueous solvent in the fine particle dispersion used in the present invention is not particularly limited as long as it is a mixed solution with water or an organic solvent that can be mixed with water. Examples of organic solvents that can be mixed with water include alcohols such as methanol, ethanol, and propanol; lower alkyl ethers of polyhydric alcohols such as ethylene glycol monomethyl ether and ethylene glycol dimethyl ether; ketones such as acetone and methyl ethyl ketone; And ethers.

  The concentration of the inorganic fine particles in the fine particle dispersion is preferably 5 to 40% by mass and more preferably 10 to 30% by mass with respect to the total mass of the dispersion. When the concentration of the inorganic fine particles is low, the solid content concentration of the coating solution to be finally prepared is lowered, and a lot of time and energy are required for drying after coating, so that the production efficiency is lowered. Moreover, when the density | concentration of an inorganic fine particle is too high, since the viscosity of a dispersion liquid will become high and a load will be applied to the handling in a post process, it is not preferable.

  The method for preparing the fine particle dispersion used in the present invention is not particularly limited. For example, a method in which hydroxy acid and a polymer are dissolved in the aqueous solvent, and inorganic fine particles are added and dispersed therein; A method in which a polymer, a hydroxy acid and inorganic fine particles are simultaneously added and dispersed; a method in which a polymer is dissolved in an aqueous solvent and then the inorganic fine particles are added and dispersed, and then a hydroxy acid is added; a hydroxy in an aqueous solvent A method of dissolving an acid, then adding and dispersing inorganic fine particles, and then adding a polymer; a method of dispersing inorganic fine particles in an aqueous solvent and then adding a polymer and a hydroxy acid can be selected. In addition, an appropriate amount of at least one of a hydroxy acid and a polymer can be added to an aqueous solvent, and after dispersing inorganic fine particles therein, the hydroxy acid and the polymer can be further added to control the desired particle size and viscosity. .

  As a means for dispersing inorganic fine particles in an aqueous solvent or an aqueous solvent containing a hydroxy acid or a polymer, either a continuous method or a batch method can be used. Further, as the disperser, various conventionally known dispersers such as a high-pressure homogenizer, an ultrasonic homogenizer, a wet media type pulverizer (sand mill, ball mill), a continuous high-speed stirring disperser, and an ultrasonic disperser are used. be able to.

  The viscosity of the fine particle dispersion used in the present invention is preferably 300 mPa · s or less, more preferably 100 mPa · s or less, in view of the storage stability of the dispersion itself and the ease of handling in subsequent steps.

  In the production of the recording medium of the present invention, a binder such as a water-soluble resin and / or a water-dispersible resin is used in the coating liquid prepared for forming the ink receiving layer together with the inorganic fine particles. . Examples of the water-soluble resin and / or water-dispersible resin used in the present invention include starch, gelatin, casein, and modified products thereof, cellulose derivatives such as methyl cellulose, carboxymethyl cellulose, and hydroxyethyl cellulose, and complete or partial saponification. Polyvinyl alcohol or modified products thereof (cation modification, anion modification, silanol modification, etc.), urea resin, melamine resin, epoxy resin, epichlorohydrin resin, polyurethane resin, polyethyleneimine resin, polyamide resin, polyvinylpyrrolidone Resin, polyvinyl butyral resin, poly (meth) acrylic acid or copolymer thereof, acrylamide resin, maleic anhydride copolymer, polyester resin, SBR latex, NBR latex, methyl Acrylic polymer latex such as methacrylate-butadiene copolymer latex and acrylate copolymer, vinyl polymer latex such as ethylene-vinyl acetate copolymer, and cationic groups or anions on these various polymer latexes And functional group-modified polymer latexes having a functional group. Preference is given to polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, having an average degree of polymerization of 300 to 5,000. The saponification degree is preferably 70 to less than 100%, particularly preferably 80 to 99.5%. In addition, these water-soluble or water-dispersible resins can be used alone or in combination.

  The amount of the binder (A) used is preferably A / B = 1/30 to 1/1, more preferably A / B = 1/20 to 1 / 1.5 in terms of the mixing mass ratio with respect to the inorganic fine particles (B). Range. If the amount of the binder is within these ranges, the formed ink-receiving layer will not easily crack or fall off, and ink absorbency will be good. Further, the method for mixing the fine particle dispersion and the binder of the present invention is not particularly limited. However, it is preferable to dissolve a water-soluble or water-dispersible resin in an aqueous medium in an amount necessary as required, and to disperse this. This is a method of mixing with a liquid, and can be mixed by either batch or continuous methods.

  The aqueous medium is not particularly limited as long as it is a mixed solution with water or an organic solvent that can be mixed with water. Examples of the organic solvent that can be mixed with water include alcohols such as methanol, ethanol, and propanol; ethylene Examples include lower alkyl ethers of polyhydric alcohols such as glycol monomethyl ether and ethylene glycol dimethyl ether; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran.

  In the recording medium of the present invention, in order to improve the film forming property, water resistance and film strength of the film formed of the inorganic fine particles and the water-soluble or water-dispersible resin, a hard film is formed in the ink receiving layer. An agent may be added. Generally, various hardeners are selected depending on the type of reactive group possessed by the polymer used. For example, in the case of a polyvinyl alcohol resin, an epoxy hardener, boric acid, a water-soluble aluminum salt, etc. Examples of the hardener used in the present invention include boron compounds such as oxygen acids centered on boron atoms or salts thereof, such as orthoboric acid, metaboric acid, Hypoboric acid, tetraboric acid, pentaboric acid and salts thereof can be preferably used.

  The amount of the hardener used varies depending on the amount of the water-soluble resin and / or water-dispersible resin used as the binder, but is generally 0.1 to 30% by mass with respect to the water-soluble resin and / or water-dispersible resin. It is good to add in the ratio. When the content of the hardener is less than 0.1% by mass with respect to the water-soluble resin and / or the water-dispersible resin, the film-forming property is lowered and sufficient water resistance cannot be obtained. On the other hand, when it exceeds 30% by mass, for example, when coating is carried out by a batch method to be described later, a change with time in the viscosity of the coating solution becomes large, and the coating stability may be lowered.

  As for the method of adding a hardener to the ink receiving layer, a method of adding a hardener directly to a coating solution containing inorganic fine particles and a binder and performing coating in a batch method; A method in which coating is performed while adding and mixing with a binder immediately before coating; a hardener is dissolved in another aqueous medium, and a coating liquid containing inorganic fine particles and a binder immediately before coating Further, there is a method of applying a solution containing a hardener before and after the application of a coating solution containing inorganic fine particles and a binder, and any method can be used.

  The solid content concentration in the coating liquid for forming the ink receiving layer is not particularly limited as long as the viscosity is such that the ink receiving layer can be formed on the support, but 5 to 5 based on the total mass of the coating liquid. 50 mass% is preferable. When the solid content concentration is less than 5% by mass, it is uneconomical to increase the coating amount in order to increase the thickness of the ink receiving layer, and to require a lot of time and energy for drying. . Moreover, when it exceeds 50 mass%, the viscosity of a coating liquid will become high and coating property may fall.

  Moreover, various additives can be mix | blended with the said coating liquid in the range which does not prevent the effect of this invention. Such additives include antifoaming agents, ink fixing agents, dot adjusting agents, colorants, fluorescent brighteners, preservatives, pH adjusting agents, penetrating agents, antistatic agents, conductive agents, ultraviolet absorbers, oxidation agents Examples thereof include an inhibitor (antifading agent).

  As a method of coating the prepared coating liquid on the support, roll coater method, blade coater method, air knife coater method, gate roll coater method, bar coater method, size press method, spin coater method, spray coater method Conventionally known coating methods such as a gravure coater method, a curtain coater method, and a die coater method can be used. Thereafter, the ink receiving layer can be formed by drying using a drying apparatus such as a hot air dryer, a thermal drum, or a far infrared dryer. The ink receiving layer in the recording medium of the present invention may be formed as a multilayer by changing the composition ratio of the polymer compound, hydroxy acid, polymer, inorganic fine particles, binder and other additives. It can be formed on one or both sides of the body. Further, for the purpose of improving the resolution and transportability of the image, smoothing processing may be performed using an apparatus such as a calendar or a cast.

A preferred range for the coating amount of the coating liquid on the support is 0.5 to 60 g / m ² in terms of solid content, and a more preferred range is 5 to 55 g / m ² . When the coating amount is less than 0.5 g / m ² , the formed ink receiving layer may not sufficiently absorb the moisture of the ink, and the ink may flow or the image may blur, and 60 g / m ^2. If it exceeds 1, curling may occur at the time of drying, or a remarkable effect may not appear as expected for printing performance.

  The recording medium of the present invention thus obtained can effectively prevent image discoloration due to acidic gas and light in the atmosphere and image bleeding under high temperature and high humidity. The reason for preventing the discoloration and fading of the image is not clear, but at least the first and / or second polymer compound suppresses the generation of radicals and peroxides in the ink receiving layer, and the hydroxy acid is It is inferred that this is supported in the form. In addition, the reason why image bleeding under high temperature and high humidity was prevented was that the hydroxyl groups of Compound A and Compound C were greatly reduced due to polymerisation, and the inherent hygroscopicity was reduced. Is presumed to be the cause.

  Further, when the ink receiving layer contains inorganic fine particles, the hydroxy acid plays a role as an aid for the above-described polymer compound and a role as a peptizer for the inorganic fine particles (alumina hydrate), but is used in a large amount. Since image bleeding under high temperature and high humidity deteriorates and beading occurs, it is necessary to control to the minimum amount necessary for peptizing inorganic fine particles. In the present invention, the fine particle dispersion used in forming the ink receiving layer is prepared by using a hydroxy acid and a polymer in combination, thereby reducing the amount of hydroxy acid, and image bleeding under high temperature and high humidity. A recording medium in which beading is effectively suppressed can be manufactured.

  The ink used for recording an image on the recording medium of the present invention is not particularly limited, but a mixture of water and a water-soluble organic solvent is used as a medium, and a dye or pigment is dissolved or dispersed as a coloring material. The common water-based ink for ink jet recording can be preferably used.

  As a method for forming an image by applying the ink to the recording medium, an ink jet recording method is particularly preferable. As the ink jet recording method, the ink is effectively separated from the nozzle and the ink is applied to the recording medium. Any method may be used as long as it can provide the above. In particular, an ink jet system in which ink subjected to the action of thermal energy undergoes a rapid volume change by a method described in Japanese Patent Application Laid-Open No. 54-59936 and the like, and ink is ejected from a nozzle by the action force due to this state change Can be used effectively.

Hereinafter, the present invention will be described specifically by way of examples. In the following examples, “part” and “%” are based on mass unless otherwise specified.
<Method for producing polymer compound 1>
Polymer compound 1 was produced as follows.
A reaction vessel equipped with a stirrer, a thermometer and a reflux condenser is charged with 109 g of acetone as a reaction solvent, and 40.00 g of 3,6-dithia-1,8-octanediol and 6.79 g of methyldiethanolamine with stirring. After dissolution, the temperature was raised to 40 ° C. and 62.07 g of isophorone diisocyanate was added. Thereafter, the temperature was raised to 50 ° C., 0.2 g of a tin-based catalyst was added, the temperature was further raised to 55 ° C., and the reaction was carried out for 4 hours while stirring.

  After completion of the reaction, the reaction solution was cooled to room temperature and cationized by adding 3.09 g of 85% formic acid. Further, 446 g of water was added, then concentrated under reduced pressure to remove acetone, and the concentration was adjusted with water to produce a polymer compound aqueous dispersion (polymer compound 1) having a solid content of 20%.

<Method for producing polymer compound 2>
Polymer compound 2 was produced as follows.
A reaction vessel equipped with a stirrer, a thermometer and a reflux condenser is charged with 81 g of acetone as a reaction solvent, and 30.00 g of 3,6-dithia-1,8-octanediol and 6 of tert-butyldiethanolamine under stirring. After dissolution of .98 g, the temperature was raised to 40 ° C. and 44.28 g of isophorone diisocyanate was added. Thereafter, the temperature was raised to 50 ° C., 0.4 g of a tin-based catalyst was added, the temperature was further raised to 55 ° C., and the reaction was carried out for 5 hours while stirring.

  After completion of the reaction, the reaction solution was cooled to room temperature and cationized by adding 4.51 g of 35% hydrochloric acid. Further, 331 g of water was added, and then a polymer compound aqueous dispersion (polymer compound 2) having a solid content of 20% was produced in the same manner as in the method for producing polymer compound 1.

<Method for producing polymer compound 3>
Polymer compound 3 was produced as follows.
A reaction vessel equipped with a stirrer, a thermometer and a reflux condenser is charged with 258 g of acetone as a reaction solvent, 40.00 g of 5-hydroxy-3,7-dithia-1,9-nonanediol and methyldiethanolamine with stirring. After dissolving 6.29 g, the temperature was raised to 40 ° C. and 54.17 g of isophorone diisocyanate was added. Thereafter, the temperature was raised to 50 ° C., 0.1 g of a tin-based catalyst was added, the temperature was further raised to 55 ° C., and the reaction was carried out for 2 hours with stirring.

  After completion of the reaction, the reaction solution was cooled to room temperature and cationized by adding 2.86 g of 85% formic acid. Further, 412 g of water was added, and a polymer compound aqueous dispersion (polymer compound 3) having a solid content of 20% was produced in the same manner as in the method for producing polymer compound 1.

<Method for producing polymer compound 4>
Polymer compound 4 was produced as follows.
A reaction vessel equipped with a stirrer, a thermometer and a reflux condenser is charged with 140 g of acetone as a reaction solvent, dissolved with stirring, 68.13 g of 3,6-dithia-1,8-octanediol and then heated to 40 ° C. On warming, 79.66 g of isophorone diisocyanate was added. Thereafter, the temperature was raised to 50 ° C., 0.4 g of a tin-based catalyst was added, the temperature was further raised to 55 ° C., and the reaction was carried out for 4 hours while stirring. After cooling to room temperature, 1,190 g of acetone was added to prepare a polymer compound acetone solution (polymer compound 4) having a solid content of 10%.

Table 1 shows synthesis components and quantitative ratios of the polymer compounds 1 to 4. Table 2 shows the weight average molecular weight and molecular weight distribution (Mw / Mn) measured by GPC (Gel Permeation Chromatography, controller: SC8010, detector: RI8012, manufactured by Tosoh Corporation). Further, infrared spectrophotometer (FT / IR-5300, manufactured by JASCO Corporation) by C = O stretching vibration of 1,730～1,690Cm ^-1 which is characteristic absorption of the urethane group, 1,540Cm around ^-1 Thus, it was confirmed that polymerization occurred in all the reactions and that the raw material components were polymerized because there were N—H bending vibration and N—H stretching vibration in the vicinity of 3,450 to 3,300 cm ⁻¹ .

上記表１の高分子化合物１〜３は２０％水分散液であり、高分子化合物４は１０％アセトン溶液である。

Polymer compounds 1 to 3 in Table 1 are 20% aqueous dispersion, and polymer compound 4 is a 10% acetone solution.

<Production of alumina hydrate>
Aluminum dodexide was produced by the method described in US Pat. No. 4,242,271. Next, the aluminum dodexide was hydrolyzed by the method described in US Pat. No. 4,202,870 to produce an alumina slurry. Water was added to the alumina slurry until the solid content of alumina hydrate was 7.7%. At this time, the pH of the alumina slurry was 9.4, and the pH was adjusted by adding a 3.9% nitric acid solution thereto. Next, aging was performed using an autoclave at pH before aging: 6.0, aging temperature: 150 ° C., aging time: 6 hours to obtain a colloidal sol. This colloidal sol was spray-dried at an inlet temperature of 87 ° C. to obtain an alumina hydrate powder. The obtained powder had a flat plate shape and was measured by X-ray diffraction to measure alumina water having a boehmite crystal structure. Showed Japanese. Further, the BET specific surface area of the obtained powder was measured using a specific surface area / pore distribution measuring apparatus (Micromeritics ASAP2400, manufactured by Shimadzu Corporation), and it was 140.5 m ² / g. .

<Preparation of fine particle dispersion A>
To 100 parts of ion-exchanged water, 0.633 parts of PAA-HCL-05 (40% aqueous solution, weight average molecular weight: about 5,000, manufactured by Nitto Boseki Co., Ltd.) as an allylamine polymer (based on alumina hydrate) 1.06) and 0.506 parts of glycolic acid (2% with respect to the alumina hydrate), a three-one motor (BL600, rated torque: 5 kgf · cm, stirring blade: turbine type (stirring blade diameter) : 86 mm), manufactured by Shinto Kagaku Co., Ltd.) and stirred at 150 rpm for 10 minutes to prepare a dispersion solvent. Then, 25.3 parts of the alumina hydrate was added while adjusting the temperature of the dispersion solvent to 25 ° C. in a low-temperature constant temperature water bath, and the number of revolutions of the three-one motor was adjusted to 350 rpm and stirred for 10 minutes. As a result, a fine particle dispersion A having a solid content concentration of alumina hydrate of 20% with respect to the total dispersion was obtained. The fine particle dispersions thus obtained were tested in the following Evaluation 1 and Evaluation 2. The results are shown in Table 3.

<Evaluation 1: Viscosity of fine particle dispersion>
The fine particle dispersion was allowed to stand for 15 minutes in a low-temperature constant temperature water bath set at 25 ° C., and then the viscosity was measured using a B-type viscometer (BM type, manufactured by Tokyo Keiki Co., Ltd.).

<Evaluation 2: Particle size of inorganic fine particles>
Using a laser particle size analyzer PARIII (manufactured by Otsuka Electronics Co., Ltd.), the average particle size of the alumina hydrate in the fine particle dispersion was measured.

<Preparation of fine particle dispersion B>
In the production of the fine particle dispersion A, JK-230 (68% aqueous solution, weight average molecular weight: about 3,000 to 5,000, manufactured by Meisei Chemical Industry Co., Ltd.) as a dicyandiamide polymer instead of an allylamine polymer 0 0.037 parts (0.1% with respect to the alumina hydrate) and the amount of glycolic acid to 0.380 parts (1.5% with respect to the alumina hydrate). A fine particle dispersion B was prepared in the same manner as the fine particle dispersion A except that the amount of ion-exchanged water was adjusted so that the solid content concentration was 20%, and the tests of Evaluation 1 and Evaluation 2 were performed. The results are shown in Table 3.

<Preparation of fine particle dispersion C>
In preparation of the fine particle dispersion A, G5632 which is an alkylamine / epihalohydrin copolymer instead of an allylamine polymer (prototype, 52.3% aqueous solution, molecular weight: 6,000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 0.048 parts (0.1% with respect to alumina hydrate) and the amount of glycolic acid to 0.380 parts (1.5% with respect to alumina hydrate) A fine particle dispersion C was prepared in the same manner as the fine particle dispersion A except that the amount of ion-exchanged water was adjusted so that the solid content concentration of the Japanese product was 20%. went. The results are shown in Table 3.

<Preparation of fine particle dispersion D>
In the preparation of the fine particle dispersion A, Charol DM-283P (91.6% white granules, molecular weight: about 28,000, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as an acrylic polymer instead of the allylamine polymer 0. 028 parts (0.1% with respect to alumina hydrate) and the amount of glycolic acid to 0.380 parts (1.5% with respect to alumina hydrate), and alumina hydrate with respect to the total dispersion A fine particle dispersion D was prepared in the same manner as the fine particle dispersion A, except that the amount of ion-exchanged water was adjusted so that the solid content concentration of the liquid became 20%, and the tests of Evaluation 1 and Evaluation 2 were performed. . The results are shown in Table 3.

<Preparation of fine particle dispersion E>
In the preparation of the fine particle dispersion A, the amount of allylamine polymer was 0.190 parts (0.3% with respect to the alumina hydrate), and glycolic acid was 0.715 parts (concentration: 88.5%). Except that the amount of ion-exchanged water was adjusted so that the solid content concentration of alumina hydrate with respect to the total dispersion was 20%. A fine particle dispersion E was prepared in the same manner as the preparation of A, and the tests of Evaluation 1 and Evaluation 2 were performed. The results are shown in Table 3.

<Preparation of fine particle dispersion F>
In the preparation of the fine particle dispersion A, the amount of allylamine polymer was 0.190 parts (0.3% with respect to the alumina hydrate), and glycolic acid was 0.511 parts (purity: 99%, 2% with respect to alumina hydrate), except that the amount of ion-exchanged water was adjusted so that the solid content concentration of alumina hydrate with respect to the total dispersion was 20%. A fine particle dispersion F was prepared in the same manner as the preparation of A, and the tests of Evaluation 1 and Evaluation 2 were performed. The results are shown in Table 3.

<Preparation of fine particle dispersion G>
In the preparation of fine particle dispersion A, allylamine polymer was not used, and glycolic acid was changed to 8.43 parts of 6% acetic acid aqueous solution (2% with respect to alumina hydrate). The fine particle dispersion G was prepared in the same manner as the fine particle dispersion A except that the amount of ion-exchanged water was adjusted so that the solid content concentration of the product was 20%, and the tests of Evaluation 1 and Evaluation 2 were performed. It was. The results are shown in Table 3.

<Preparation of fine particle dispersion H>
In the preparation of the fine particle dispersion A, allylamine polymer is not used, the amount of glycolic acid is 0.759 parts (3% with respect to alumina hydrate), and the solid content concentration of alumina hydrate with respect to the total dispersion A fine particle dispersion H was prepared in the same manner as the fine particle dispersion A, except that the amount of ion-exchanged water was adjusted to 20%, and the tests of Evaluation 1 and Evaluation 2 were performed. The results are shown in Table 3.

<Preparation of fine particle dispersion I>
In the preparation of the fine particle dispersion A, the fine particle dispersion A was used except that the allylamine polymer was not used and the amount of ion-exchanged water was adjusted so that the solid content concentration of the alumina hydrate with respect to the total dispersion was 20%. A fine particle dispersion I was prepared in the same manner as described above, and the tests of Evaluation 1 and Evaluation 2 were performed. The results are shown in Table 3.

<Preparation of fine particle dispersion J>
In the preparation of the fine particle dispersion E, the fine particle dispersion E was used except that the amount of ion-exchanged water was adjusted so that the solid content concentration of the alumina hydrate was 20% with respect to the total dispersion without using the allylamine polymer. A fine particle dispersion J was prepared in the same manner as in the above, and tests of Evaluation 1 and Evaluation 2 were performed. The results are shown in Table 3.

<Preparation of fine particle dispersion K>
In the preparation of the fine particle dispersion F, the fine particle dispersion F was used except that the allylamine polymer was not used and the amount of ion-exchanged water was adjusted so that the solid content concentration of alumina hydrate relative to the total dispersion was 20%. A fine particle dispersion K was prepared in the same manner as in the preparation of No. 1 and the tests of Evaluation 1 and Evaluation 2 were performed. The results are shown in Table 3.

<Example 1>
To 100 parts of the fine particle dispersion A prepared previously, 0.4 part of boric acid (20% with respect to polyvinyl alcohol) and 10 parts of polymer compound 1 (20% aqueous dispersion) with respect to alumina hydrate (10 parts). Further, 40 parts of a 5% aqueous solution of polyvinyl alcohol (PVA245, manufactured by Kuraray Co., Ltd.) was added (10% with respect to the alumina hydrate) and stirred with a three-one motor until uniform. A working solution was prepared. Thereafter, a polyethylene-coated paper (thickness: 224 μm, basis weight 234 g / m ² ; 60-degree specular gloss of 64% according to JIS-Z-8741) is used as a support, and the coating solution prepared above is dried on it. The recording medium of the present invention was coated with a Mayer bar so that the coating amount was 35 g / m ^2, and dried at 110 ° C. for 20 minutes with a constant air dryer (FC-610, manufactured by Toyo Seisakusho Co., Ltd.). Was made. The following evaluations 3 to 6 were performed on the obtained recording medium. The results are shown in Table 4.

Various physical properties of the recording medium were evaluated in the following manner.
<Evaluation 3: Evaluation Method for Suppressing Discoloration / Discoloration Effect by Gas>
Recording with discoloration and discoloration caused by ozone exposure using black (Bk) ink and cyan (C) ink in a single color and 100% ink amount using an inkjet recording device (BJ F870, manufactured by Canon Inc.) The medium is placed in an ozone exposure tester (made by Suga Test Instruments Co., Ltd., special order), exposed to ozone at a concentration of 3 ppm for 4 hours under the conditions of 40 ° C. and 55% RH, and the optical density of Bk ink and C ink is optically measured. Measurement was performed using a reflection densitometer (RD-918, manufactured by Greta Macbeth Co., Ltd.), and the remaining OD ratio was calculated and evaluated from the following formula (1).

<Evaluation 4: Evaluation Method for Suppressing Discoloration / Discoloration Effect by Light>
Using an ink jet recording apparatus (BJ F870, manufactured by Canon Inc.), a recording medium on which solid printing of magenta (M) ink with a single color and an ink amount of 100% is performed is an atlas fade meter (conditions: irradiation at a wavelength of 340 nm). The strength was 0.39 W / m ² , the temperature was 45 ° C., and the humidity was 70%. After 100 hours, the optical density of M ink was measured using an optical reflection densitometer (RD-918, manufactured by Greta Macbeth Co.). Evaluation was performed by calculating the remaining OD ratio from the equation (1).

<Evaluation 5: Evaluation method for image bleeding under high humidity>
Using an inkjet recording apparatus (BJ F870, manufactured by Canon Inc.), solid printing with a single color of black (Bk) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink (100% ink amount) The exposed recording medium was exposed to an environment of 30 ° C. and 80% RH for 1 week, and the degree of image blurring was visually evaluated. For each color, “◯” indicates that no bleeding occurs, “Δ” indicates that bleeding slightly occurs in any of the colors, and “X” indicates that bleeding greatly occurs in any of the colors.

<Evaluation 6: Evaluation method for beading>
Using an inkjet printer (BJ F870, manufactured by Canon Inc.), solid printing of green (mixed color of yellow 100% and cyan 100%, ink ejection amount: 200%) is performed, and the degree of beading is determined by the print density. Evaluation was based on the size of the high granular part. Granular part where beading is not observed or slightly beading and the granular part with high printing density is less than 0.1 mm is marked with “◯”, and beading occurs and the printing part has high printing density. “Δ” is the size of 0.1 mm or more and less than 0.3 mm, and “x” is the case where the diameter of the granular portion having a high printing density is 0.3 mm or more or where the printing density is low.

<Example 2>
A recording medium of the present invention was produced in the same manner as in Example 1 except that the polymer compound 1 was changed to the polymer compound 2 in Example 1, and tests 3 to 6 were performed. The results are shown in Table 4.

<Example 3>
A recording medium of the present invention was produced in the same manner as in Example 1 except that the polymer compound 1 was changed to the polymer compound 3 in Example 1, and tests 3 to 6 were performed. The results are shown in Table 4.

<Example 4>
In Example 1, an ink receiving layer was formed on polyethylene-coated paper in the same manner as in Example 1 except that the polymer compound 1 was not added. Thereafter, the polymer compound 4 (10% acetone solution) was overcoated with a Mayer bar so that 10% in terms of solid content was added to the alumina hydrate in the ink receiving layer (here, the polymer compound 4). The ink-receptive layer overcoated with an ink was adjusted to have a dry weight of 35 g / m ² ), and dried at 110 ° C. for 10 minutes with an air blowing constant temperature dryer (FC-610, manufactured by Toyo Seisakusho Co., Ltd.). The recording medium of the present invention was produced, and tests 3 to 6 were performed. The results are shown in Table 4.

<Example 5>
A recording medium of the present invention was produced in the same manner as in Example 1 except that the fine particle dispersion A was changed to the fine particle dispersion B in Example 1, and the tests of Evaluations 3 to 6 were performed. The results are shown in Table 4.

<Example 6>
A recording medium of the present invention was produced in the same manner as in Example 1 except that the fine particle dispersion A was changed to the fine particle dispersion C in Example 1, and the tests of Evaluations 3 to 6 were performed. The results are shown in Table 4.

<Example 7>
A recording medium of the present invention was prepared in the same manner as in Example 1 except that the fine particle dispersion A was changed to the fine particle dispersion D in Example 1, and the tests of Evaluations 3 to 6 were performed. The results are shown in Table 4.

<Example 8>
A recording medium of the present invention was produced in the same manner as in Example 1 except that the fine particle dispersion A was changed to the fine particle dispersion E in Example 1, and the tests of Evaluations 3 to 6 were performed. The results are shown in Table 4.

<Example 9>
A recording medium of the present invention was produced in the same manner as in Example 1 except that the fine particle dispersion A was changed to the fine particle dispersion F in Example 1, and the tests of Evaluations 3 to 6 were performed. The results are shown in Table 4.

<Comparative Example 1>
A recording medium of a comparative example was produced in the same manner as in Example 1 except that the fine particle dispersion A was changed to the fine particle dispersion G in Example 1, and the tests of Evaluations 3 to 6 were performed. The results are shown in Table 4.

<Comparative example 2>
A recording medium of a comparative example was produced in the same manner as in Example 2 except that the fine particle dispersion A was changed to the fine particle dispersion G in Example 2, and the tests of Evaluations 3 to 6 were performed. The results are shown in Table 4.

<Comparative Example 3>
A recording medium of a comparative example was produced in the same manner as in Example 3 except that the fine particle dispersion A was changed to the fine particle dispersion G in Example 3, and the tests of Evaluations 3 to 6 were performed. The results are shown in Table 4.

<Comparative example 4>
A recording medium of a comparative example was produced in the same manner as in Example 4 except that the fine particle dispersion A was changed to the fine particle dispersion G in Example 4, and the tests of Evaluations 3 to 6 were performed. The results are shown in Table 4.

<Comparative Example 5>
In Example 1, except that the fine particle dispersion A was changed to the fine particle dispersion G and the polymer compound 1 was not used, a recording medium of a comparative example was prepared in the same manner as in Example 1, and evaluations 3 to 6 were performed. Was tested. The results are shown in Table 4.

<Comparative Example 6>
A recording medium of a comparative example was produced in the same manner as in Example 1 except that the polymer compound 1 was not used in Example 1, and the tests of Evaluations 3 to 6 were performed. The results are shown in Table 4.

<Comparative Example 7>
In Example 1, except that the fine particle dispersion A was changed to the fine particle dispersion H and the polymer compound 1 was not used, a recording medium of a comparative example was produced in the same manner as in Example 1, and evaluations 3 to 6 were performed. Was tested. The results are shown in Table 4.

<Reference Example 1>
In Example 1, the coating liquid was adjusted in the same manner as in Example 1 except that the fine particle dispersion A was changed to the fine particle dispersion I and the polymer compound 1 was not used. It was difficult to produce a medium, and evaluation was not achieved.

<Reference Example 2>
In Example 1, the fine particle dispersion A was changed to the fine particle dispersion J, and a coating solution was prepared in the same manner as in Example 1 except that the polymer compound 1 was not used. It was difficult to produce a medium, and evaluation was not achieved.

<Reference Example 3>
In Example 1, the fine particle dispersion A was changed to the fine particle dispersion K, and the coating liquid was adjusted in the same manner as in Example 1 except that the polymer compound 1 was not used. It was difficult to produce a medium, and evaluation was not achieved.

  As apparent from the above results, the first polymer compound and / or the second polymer compound, hydroxy acid, alkylamine / epihalohydrin copolymer, dicyandiamide, allylamine, and acrylic polymer The recording media (Examples 1 to 9) of the present invention containing at least one polymer selected from those of Comparative Examples 1 to 7 that do not contain the polymer compound, the hydroxy acid, and the polymer at the same time. The recording medium exhibits superior characteristics in all of gas resistance, light resistance, and bleeding of images under high temperature and high humidity.

  Further, from Table 3, the same amount of the fine particle dispersion prepared by using in combination at least one polymer selected from hydroxy acid and alkylamine / epihalohydrin copolymer, dicyandiamide, allylamine and acrylic polymer It was lower in viscosity than a fine particle dispersion prepared with only hydroxy acid, and was suitable for dispersion and peptization of inorganic fine particles, and it was particularly easy to handle during coating. As described above, the method of using the hydroxy acid in combination with the above specific polymer is suitable for dispersing and peptizing inorganic fine particles by reducing the amount of hydroxy acid. In the recording media of Examples 1 to 9 in which the ink receiving layer is formed by using the fine particle dispersion and the polymer compound together, beading is effectively suppressed, and further, an irritating odor (or unpleasant odor) is generated during printing. It did not occur. Although the beading was suppressed even in the case of using acetic acid (Comparative Examples 1 to 5), since the acetic acid odor was generated during printing, the recording medium of the present invention suppressed the irritating odor (or unpleasant odor). It is also excellent in that it is.

According to the present invention, at least the first and / or second polymer compound, the specific organic acid (hydroxy acid), and the specific polymer are contained in the ink receiving layer, whereby It was possible to produce a recording medium in which discoloration and bleeding of images under high temperature and high humidity were suppressed. In addition, in the method for producing a recording medium, when forming the ink-receiving layer, in addition to containing the first and / or second polymer compound, inorganic fine particles, a specific polymer, and a hydroxy acid In addition to the above weather resistance, an irritating odor (or unpleasant odor) is suppressed, and a recording medium capable of high-quality image recording with excellent ink absorbability can be produced. did it.

Claims (9)

In a recording medium in which at least one ink receiving layer containing at least one inorganic fine particle and a polymer compound obtained by reacting the following compound A, compound B and compound C is provided on at least one surface of a support. At least one amino group of the polymer compound is at least one selected from phosphoric acid, phosphorous acid, formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, lactic acid, pyruvic acid, methanesulfonic acid, hydrochloric acid and nitric acid by a cationized polymer compound, and further hydroxy acids the ink-receiving layer, alkylamine-epihalohydrin copolymer, dicyandiamide, allylamine-based and at least one polymer selected from an acrylic polymer A recording medium containing the inorganic fine particles dispersed in the polymer .
A: Sulfur-containing organic compound having two or more active hydrogen groups B: Polyisocyanate compound having two or more isocyanate groups
C: Amine compound having two or more active hydrogen groups The recording medium according to claim 1, wherein the sulfur-containing organic compound A contains at least one sulfide group in the molecule. The recording medium according to claim 1 , wherein the amine compound C is a tertiary amine represented by the following general formula (1).

(In the formula, any one of R ¹ , R ² , and R ³ is an alkyl group having 1 to 6 carbon atoms, an alkanol group, or an aminoalkyl group, and the others may be the same or different. Represents an aminoalkyl group or an alkanethiol group.)   The recording medium according to claim 1, wherein the hydroxy acid is a monocarboxylic acid. The recording medium according to any one of claims 1 to 4 , wherein the polymer is at least one polymer selected from the following general formulas (2) to (5).

(In the formula, R ¹ and R ² represent a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, and a benzyl group. R ³ , R ⁴ , and R ⁵ are a hydrogen atom and an alkyl that may have a substituent. Group, alkenyl group, alkanol group, allylalkyl group, allylalkenyl group, and R ¹ , R ² and R ³ , R ⁴ , R ⁵ may be the same or different, and R ⁶ is hydrogen. Represents an atom or a methyl group, R ⁷ represents an optionally branched alkylene group having 1 to 10 carbon atoms, R ⁸ and R ⁹ each independently represents an alkyl group having 1 to 4 carbon atoms, and R ¹⁰ represents Each represents an alkyl group having 1 to 8 carbon atoms, an arylalkyl group or an alicyclic alkyl group, A represents —COO— or —CONH—, and X ⁻ represents an inorganic or organic anion. n is an integer indicating the degree of polymerization.) In the method for producing a recording medium in which an ink receiving layer is provided by coating a coating liquid on at least one surface of a support, the coating liquid is composed of inorganic fine particles, hydroxy acid, and an alkylamine / epihalohydrin copolymer. things, dicyandiamide, a step of the allylamine and at least one polymer with dispersed in a liquid medium fine particle dispersion is selected from an acrylic polymer, a fine particle dispersion, of claim 1-3 A method for producing a recording medium, which is prepared by adding the polymer compound according to any one of the above items. The method for producing a recording medium according to claim 6 , wherein the inorganic fine particles are alumina and / or alumina hydrate. The method for producing a recording medium according to claim 6 , wherein the polymer is at least one polymer selected from the general formulas (2) to (5). The method for producing a recording medium according to claim 6 , wherein the hydroxy acid is a monocarboxylic acid.