JP4490884B2 - Recording medium - Google Patents

Description

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

  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 ink jet method can obtain a recording that is inferior to an image by a multicolor printing by a plate making method or an image by a color photographic method. 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 fading 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, in the conventional methods using these low molecular weight compounds, even those compounds that are effective in gas resistance and light resistance cannot be added to water-based coating liquids or are water-soluble. However, there is an adverse effect of worsening the water resistance and image bleeding under high temperature and high humidity, and it is difficult to add an amount sufficient to improve the performance of the recording medium.

  On the other hand, as a means for solving various problems in these low molecular compounds, a recording medium containing a high molecular compound having a discoloration or fading preventing effect incorporating a unit such as a sulfide group has been proposed. For example, Patent Document 16 discloses a recording medium containing a copolymer of a diallylamine compound and an ethylenically unsaturated compound having a sulfide group or a thiocarbonyl group. Patent Document 17 discloses an alkylthio group, an arylthio group, a thiocarbonyl group. And a recording medium containing a cationic polyurethane having any of thiocyanate groups. However, these high molecular compounds have a low discoloration / fading prevention effect with respect to the amount added compared to the low molecular weight compounds, and when applied to a recording medium having a void type ink receiving layer, the improvement effect is sufficiently high. When an amount that can be expressed is added, there is a problem that ink absorbability and image density are lowered.

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 JP 2003-089266 A JP 2004-345309 A

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

  The present inventors are capable of high-quality image recording with high image density and excellent ink absorbability, and image discoloration due to acidic gas and light in the atmosphere and image bleeding under high temperature and high humidity. As a result of various investigations for obtaining a recording medium effectively prevented, a polymer compound obtained by reacting a sulfur-containing organic compound in the ink receiving layer was added, and the specific surface area and fineness of the ink receiving layer were added. The inventors have found that the above-mentioned problems can be solved by setting the pore volume to a specific range, and have completed the present invention.

That is, the present invention provides a recording medium comprising an ink receiving layer having a void on at least one surface of a support, wherein the ink receiving layer has a sulfur-containing organic compound (A ) having two or more active hydrogen groups. ), A polyisocyanate compound (B) having two or more isocyanate groups, and an amine compound (C) having two or more active hydrogen groups, and at least one of the amino groups of the amine compound (C). A polymer compound partially cationized with an acid , and alumina hydrate fine particles as inorganic fine particles , and specific surface area A (m ² / g) and pore volume V (cm) of the ink receiving layer by BET method ³ / g) satisfies the relationship of the following formula (1) and the following formula (2).
75 ≦ A ≦ 92 (Formula 1)
0.55 ≦ V ≦ 2.00 (Formula 2)

In the present invention, the acid 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. ; Contact and the inorganic fine particles, it is preferable that at least one of the specific surface area and pore volume were mixed different alumina hydrate fine particles.

  With the configuration of the present invention, high-quality image recording with high image density and excellent ink absorbability is possible, and further, the color of the image is deteriorated due to acid gas or light in the atmosphere and under high temperature and high humidity. It is possible to provide a recording medium in which image bleeding is effectively prevented.

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, the recording medium of the present invention is obtained by forming an ink receiving layer containing a polymer compound obtained by reacting a sulfur-containing organic compound on the support.

The polymer compound is a reaction product (hereinafter referred to as “polymer”) comprising a sulfur-containing organic compound (A) having two or more active hydrogen groups and a polyisocyanate compound (B) having two or more isocyanate groups as raw material components. Compound I ”), and in addition to the compound A and the compound B, an amine compound (C) having two or more active hydrogen groups is reacted, and at least a part of the amino group of the resulting polymer compound is is more that cationized (hereinafter referred to as "polymer compound II") to the acid.

  The compound A which is a raw material component of the polymer compounds I and II is not particularly limited, but is preferably a compound having at least one sulfide group in the molecule, specifically, the following general formulas (1) to ( The compound represented by 6) can be mentioned. Further, the following sulfur-containing organic compounds A can be used alone or in combination of two or more, and the polymer compounds I and II used in the present invention can be synthesized.

（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 that is a raw material component of the polymer compounds I and II 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, trimethyl Samethylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, hydrogenated xylylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate However, it is not limited to these. Moreover, it is possible to synthesize polymer compounds I and II used in the present invention by using these polyisocyanate compounds alone or in combination of two or more thereof.

  The polymer compound I 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 obtained polymer compound I 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 obtained polymer compound I, the proportion of units derived from compound A in polymer compound I 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 the above range, the polymer compound I having a sufficient image discoloration or fading preventing effect cannot be obtained. On the other hand, when the content of the compound A unit is in a proportion exceeding the above range, the resulting polymer compound I becomes expensive, and the amount of the compound A unit with respect to the coating liquid when the ink receiving layer is formed using the polymer compound I is high. The solubility and dispersibility may be inferior. The weight average molecular weight of the polymer compound I 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 polymer compound II used in the present invention, in the reaction of the compound A and the compound B, an amine compound C having two or more active hydrogen groups is further reacted, and the resulting compound C contains compound C. It is preferred to incorporate the unit and cationize at least some of the amino groups in the unit. The compound C is preferably a tertiary amine as represented by the following general formula (7).

(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.)

  Specific examples of the compound represented by the general formula (7) include, for example, N-methyl-N, N-diethanolamine, N-ethyl-N, N-diethanolamine, N-isobutyl-N, N— as diol compounds. Examples include diethanolamine, Nt-butyl-N, N-diethanolamine, and Nt-butyl-N, N-diisopropanolamine. 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 polymer compound II used in the present invention.

  The polymer compound II used in the present invention reacts with compound A, compound B and compound C as described above, and the compound A unit, compound B unit and compound C unit (the tertiary amino group in the unit is cationized). Is obtained as a polymer containing in the molecule. In order to fully express the function of the polymer compound II, the content of the compound C in the polymer compound II is preferably in the range of 5.5 to 18.5% by molar ratio. When the content of Compound C is lower than 5.5% in terms of molar ratio, the content of hydrophilic groups decreases, making it difficult to prepare an aqueous dispersion of Polymer Compound II, and forming an ink receiving layer. In some cases, it may be difficult to blend the aqueous coating liquid. 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 II.

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

  In the polymer compound II used in the present invention, if the content of the compound C is in the range described above, the mass of the compound A unit incorporated in the polymer compound II is 10 to 65 in the polymer compound II. It is preferable to occupy% by mass. More preferably, it is the ratio which occupies 30-65 mass%. When the proportion of the compound A unit is less than 10% by mass, the image discoloration / fading prevention effect 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 II. .

  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 range described above, the mass of Compound B unit is obtained. It is preferable to occupy 10 to 80% by mass in the obtained polymer compound II. 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 sufficiently exhibit the functions of each unit of the compound A and the compound C can be combined.

  In addition, the production method of the polymer compound II 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 C). The so-called prepolymer method may be used in which a prepolymer having a terminal isocyanate group is produced by reacting the compound B with the compound B in a ratio rich in isocyanate groups, and the prepolymer and the compound C (or compound A) are reacted. Good. In any method, a chain extender such as a low molecular weight polyol or a low molecular weight diamine may be used in combination. The molecular weight of the obtained polymer compound II 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 polymer compound I or II thus obtained is preferably in the range of 1,000 to 150,000, more preferably in the range of 2,000 to 50,000, although it depends on the reaction conditions. . 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.

  In the production of the polymer compound I or II used in the present invention, a compound D having two or more active hydrogen groups other than the compound A and the compound C may be copolymerized as necessary. As such compound D, the following polyester polyols, polyether polyols, or polycarbonate polyols may be used alone, or two or more of them may be used simultaneously to synthesize polymer compound I or II used in the present invention. Is possible.

  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 polymer compounds I and II 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.

The polymer compound II used in the present invention is dispersed in water by cationizing at least a part of the tertiary amino group of the compound C unit contained therein with an acid before or after the synthesis of the polymer compound II. Can be dissolved.
In particular , in order to disperse or dissolve the polymer compound II in water with a preferable 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. 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 polymer compound II cationized using a polyvalent acid other than phosphoric acid may cause thickening when it is dispersed or dissolved in water. In addition, polymer compound II cationized with hydroxy acids such as glycolic acid and lactic acid, when applied to recording media, suppresses yellowing of white paper compared to polymer compound II cationized with other acids. In particular, it can be used preferably.

  Particularly preferred among the polymer compounds II used in the present invention obtained by the above method are compounds represented by the following general formulas (8) to (13).

（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 or double alicyclic rings, and R ₁₀ is carbon number 1) ˜4, 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 with a weight average molecular weight of 1,000 to 150,000. .)

（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。なお、Ｒ₉〜₁₂およびＸ^-およびｍは一般式（８）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 (8).)

（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（８）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 (8).)

（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。なお、Ｒ₉〜₁₂およびＸ^-およびｍは一般式（８）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 (8).)

（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。なお、Ｒ₉〜₁₂およびＸ^-およびｍは一般式（８）と同義である。）

(Wherein R ₆ and R ₇ each independently represents 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 (8).)

（式中Ｒ₈は水酸基またはアルキル基を表す。なお、Ｒ₉〜₁₂およびＸ^-およびｍは一般式（８）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 meaning as in formula (8).)

  When the polymer compound II 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 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” (Edited by Kyoritsu Publishing Society of Polymer Science). Chem. Phys., 70 (B), 15 Apl., 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.

  The recording medium of the present invention is characterized in that the ink receiving layer contains the polymer compound I and / or polymer compound II (hereinafter sometimes simply referred to as “polymer compound”) used in the present invention. The ink receiving layer is formed by applying a coating solution in which other additives such as the above polymer compound, a suitable binder, a suitable inorganic fine particle, and a cationic polymer are dispersed and dissolved in an aqueous solvent on the surface of a suitable support. The ink receiving layer is formed by a method of coating and drying, or a coating solution not containing a polymer compound, and then an appropriate method, for example, an overcoat method, to put the polymer compound in the ink receiving layer. It is carried out by a method of impregnation.

  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, and more preferably is 0.00 in terms of solid content with respect to the ink receiving layer. The range is from 05 to 15% by mass, and more preferably from 0.05 to 10% by mass in terms of solid content with respect to the ink receiving layer. If the content is within this range, discoloration or discoloration of the image due to gas and light in the atmosphere and image bleeding under high temperature and high humidity can be effectively prevented. 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, and if the content exceeds 20% by mass, There is a risk of deteriorating ink absorbability and decreasing print density.

The recording medium of the present invention preferably has a fine voids in the ink receiving layer to absorb the ink, addition of inorganic fine particles in order to form such a gap. The inorganic fine particles are preferably fine particles that have high ink absorbability, excellent color developability, and can form high-quality images. Examples of such inorganic fine particles, the alumina hydrate product is like et be.

  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 experiments and morphology observation Chapter 1 Light Scattering (Kyoritsu Shuppan Polymer Society)” or “J Chem. Phys., 70 (B), 15 Apl., 3965 (1979) ”.

The specific surface area of the inorganic fine particles is preferably in the range of 50 to 500 m ² / g, and the specific surface area of the ink receiving layer described later is formed by using a single particle or several particles having different specific surface areas in combination. Use what you can. In addition, the specific surface area as used in the field of this invention can be calculated | required by BET method. The BET method is one of the methods for measuring the surface area of a powder by a vapor phase adsorption method, and is a method for obtaining the total surface area, that is, the specific surface area of a 1 g sample from an adsorption isotherm. Usually, nitrogen gas is used as the adsorbed gas, and a method of measuring the amount of adsorption from the change in pressure or volume of the gas to be adsorbed is common. A prominent expression of the isotherm of multimolecular adsorption is the Brunauer Emmett Teller equation (BET equation). The amount of adsorption is obtained based on this equation, and the surface area is obtained by multiplying the area occupied by one adsorbed molecule on the surface.

The pore volume of the inorganic fine particles is preferably in the range of 0.1 to 2.0 cm ³ / g, and a single particle or several particles having different pore volumes are used in combination to form an ink receiving layer described later. The one that can form the pore volume is used. The pore volume as used in the present invention can be measured by a gas phase adsorption method.

In the present invention, as no machine microparticles, alumina hydrate thereof can be preferably used, further, excellent in transparency and smoothness of the formed ink-receiving layer, it is possible to form a finer voids, also positive charge particle surface And alumina hydrate having a boehmite structure or a pseudoboehmite structure can be used more preferably from the viewpoint of good fixability of the dye in the ink.

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 (14).

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 a light van 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. Here, the long-chain aluminum alkoxide is, for example, an alkoxide having 5 or more carbon atoms, and when an alkoxide having 12 to 22 carbon atoms is used, the removal of alcohol as described later, and the alumina hydrate Since shape control becomes easy, it is preferable. The method based on the hydrolysis of the aluminum alkoxide has an advantage that impurities such as various ions are less likely to be mixed as compared with a method for producing alumina hydrogel or cationic alumina. Furthermore, since long-chain aluminum alkoxide is easy to remove long-chain alcohol after hydrolysis, for example, compared with the case of using short-chain alkoxide such as aluminum isoproxide, the alcohol hydrate is completely dealcoholized. There is also the advantage that it can be done.

  The alumina hydrate obtained by the above method can control the particle shape of the alumina hydrate to a specific range by adjusting the conditions of the aging process for growing the 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, it is preferable to add an acid to obtain a dispersion.

  In the present invention, when the inorganic fine particles 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. A peptizer is generally used for the preparation of the dispersion, and as such a peptizer, conventionally known peptizers can be used. For example, formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, lactic acid, pyruvic acid, Examples thereof include organic acids such as methanesulfonic acid and inorganic acids such as hydrochloric acid and nitric acid, and one or more of them can be freely selected and used. Further, instead of using an acid as a peptizer, a dispersion can be prepared using various surfactants or polymer dispersants. Further, a fine particle dispersion may be prepared by using an organic acid and a cationic polymer in combination and dispersing and peptizing inorganic fine particles in an aqueous solvent.

  The amount of acid used varies depending on the amount of inorganic fine particles used, the particle size, and the specific surface area, but may be the minimum amount necessary for peptizing the fine particles in a water-soluble solvent, and preferably for the inorganic fine particles. The range of 0.1 to 10% by mass, more preferably 0.5 to 5% by 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, and the acid concentration remaining in the ink receiving layer increases. As a result, the pH of the ink receiving layer itself is lowered, and beading may occur, resulting in a significant decrease in image quality.

  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 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 method for preparing the fine particle dispersion used in the present invention is not particularly limited. For example, a method in which an acid is dissolved in the aqueous solvent and inorganic fine particles are added thereto and dispersed; an appropriate amount of acid is added in the aqueous solvent. Then, after dispersing the inorganic fine particles, an acid may be further added to control the particle size and viscosity to a desired level.

  As a means for dispersing inorganic fine particles in an aqueous solvent or an aqueous solvent containing an acid, 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 not particularly limited, but may be any degree as long as the storage stability of the dispersion itself is good and does not place a burden on handling in the subsequent process, and is preferably 300 mPa · s or less. Preferably it is 100 mPa · s or less.

  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 resins 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 of mixing the inorganic fine particles and the binder used in the present invention is not particularly limited, but preferably, a water-soluble resin or a water-dispersible resin is dissolved in an aqueous medium in an amount necessary as necessary, and the fine particles are mixed. This is a method of mixing with a dispersion, and can be mixed by either a batch method or a continuous method.

  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.

  Further, 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 by the inorganic fine particles and the water-soluble resin or the water-dispersible resin, the ink receiving layer is hardened. A film 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.

  Further, the method for adding the polymer compound to the ink receiving layer is not particularly limited. For example, a method in which the polymer compound is added directly to a coating solution containing inorganic fine particles and a binder and coating is performed in a batch system; A method in which a polymer compound is added in advance to either a fine particle dispersion or a liquid containing a binder, and coating is performed while mixing with the liquid containing the binder or the fine particle dispersion immediately before coating; A method in which a molecular compound is dispersed in another aqueous medium and added in-line to a coating liquid containing inorganic fine particles and a binder immediately before coating; and further, before and after coating of a coating liquid containing inorganic fine particles and a binder, There is a method of applying a liquid containing a polymer compound, and any method can be used.

  Therefore, the recording medium of the present invention has a structure in which an ink receiving layer containing at least the polymer compound is provided on a support; a coating liquid containing the polymer compound is overcoated on the ink receiving layer. Or a configuration in which an ink receiving layer is formed by applying a small amount of a coating solution containing the polymer compound on the surface of the support. In the present invention, these configurations are also included as “an ink receiving layer formed on the surface of the support”.

  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 (anti-fading 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 in multiple layers by changing the composition ratio of the polymer compound, inorganic fine particles, binder and other additives, and may be formed on one side or both sides of the support. It is possible to form. 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.

Further, it formed a specific surface area of the ink receiving layer (A) is 75 m ² / g or more, more preferably from 75~300m ² / g, furthermore preferably 75~200m ² / g. When the specific surface area is less than 75 m ² / g, the image density is lowered, and the printed matter tends to be white and dull. Further, when the specific surface area exceeds 300 m ² / g, the ink absorbability may be lowered. Furthermore, the pore volume (V) of the formed ink receiving layer is 0.55 cm ³ / g or more, more preferably in the range of 0.55 to 2.00 cm ³ / g, in the above range. More preferably, it is in the range of 0.55 to 1.00 cm ³ / g. When the pore volume is less than 0.55 cm ³ / g, the ink cannot be sufficiently absorbed, and the ink may flow or the image may blur. On the other hand, if the pore volume exceeds 2.0 cm ³ / g, the print density and gloss of the image may be lowered.

  The recording medium of the present invention obtained in this way is capable of high-quality image recording with excellent ink absorbability, image discoloration due to atmospheric acid gas or light, and high temperature and high humidity. It is possible to effectively prevent image bleeding. Although the reason for preventing the discoloration and fading of the image is not clear, it is presumed that at least the polymer compound suppresses the generation of radicals and peroxides in the ink receiving layer. 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.

  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, “parts” and “%” are based on mass unless otherwise specified.
<Method for producing polymer compound A>
Polymer compound A was produced as follows.
A reaction vessel equipped with a stirrer, a thermometer and a reflux condenser was 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 were dissolved under stirring. Thereafter, 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 performed 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 A) having a solid content of 20%.

<Method for producing polymer compound B>
Polymer compound B was produced as follows.
A reaction vessel equipped with a stirrer, a thermometer and a reflux condenser was charged with 81 g of acetone as a reaction solvent, 30.00 g of 3,6-dithia-1,8-octanediol and tert-butyldiethanolamine with stirring. After dissolving 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 B) having a solid content of 20% was produced in the same manner as in the method of producing polymer compound A.

<Method for producing polymer compound C>
Polymer compound C 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 then a polymer compound aqueous dispersion (polymer compound C) having a solid content of 20% was produced in the same manner as in the method of producing polymer compound A.

<Method for producing polymer compound D>
Polymer compound D 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 D) having a solid content of 10%.

Table 1 shows synthesis components and quantitative ratios of the polymer compounds A to D. 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). In addition, absorption (1,730 to 1,690 cm ⁻¹ C═O stretching vibration, 1,540 cm ⁻ ) showing the characteristics of a urethane group by an infrared spectrophotometer (FT / IR-5300, manufactured by JASCO Corporation). ¹ near N-H deformation vibration, since the detection of the 3,450～3,300Cm N-H stretching vibration in the vicinity of ^-1), occurs polymerized in all reactions, that raw material components was polymerized confirmed.

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

Polymer compounds A to C in Table 1 are 20% aqueous dispersions, and polymer compound D is a 10% acetone solution.

<Preparation of alumina dispersion A>
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, using an autoclave, aging was carried out at pH before aging: 6.0, aging temperature: 150 ° C., and aging time: 6 hours to obtain a colloidal sol. This colloidal sol was spray-dried at an inlet temperature of 87 ° C. to obtain alumina hydrate. Further, 27.3 parts of the obtained alumina hydrate and 9.10 parts of a 6% -acetic acid aqueous solution (2% with respect to the alumina hydrate) were added to 100 parts of ion-exchanged water. , Manufactured by Shinto Kagaku Co., Ltd.) at 350 rpm for 10 minutes to prepare an alumina dispersion A having a solid content concentration of 20%.
<Preparation of alumina dispersion B>
Alumina dispersion B was produced in the same manner as the alumina dispersion A except that the aging temperature was 175 ° C. and the aging time was 5 hours.

<Preparation of alumina dispersion C>
Aluminum octoxide was synthesized by the method described in US Pat. No. 4,242,271 and US Pat. No. 4,202,870, and this was hydrolyzed to produce an alumina slurry. Water was added to the alumina slurry until the solid content of alumina hydrate was 5%. Next, after raising the temperature to 80 ° C. and performing an aging reaction for 10 hours, spray drying was performed to obtain alumina hydrate. Further, this alumina hydrate is mixed and dispersed in ion-exchanged water, adjusted to pH 5 with nitric acid, then heated to 95 ° C., adjusted to pH 10 by adding sodium aluminate, and subjected to aging reaction for 12 hours. The colloidal sol was obtained. The colloidal sol was desalted and then peptized by adding acetic acid to prepare an alumina dispersion C having a solid concentration of 20%.

<Evaluation 1: Specific surface area and pore volume of alumina hydrate>
Alumina dispersions A to C were dried at 60 ° C. to obtain alumina hydrates A to C. Further, the obtained alumina hydrate was vacuum degassed at 120 ° C. for 24 hours, and then measured using a specific surface area / pore distribution measuring device (TriSter3000, manufactured by Micromeritics (Shimadzu Corporation)). . Nitrogen was used as the adsorption gas. The specific surface area was determined by the BET method, and the pore volume was determined from the total pore volume of pores having a pore radius of 100 nm or less. The obtained values are shown in Table 3.

<Evaluation 2: Crystal structure of alumina hydrate>
Alumina dispersions A to C were dried at 60 ° C. to obtain alumina hydrates A to C. The obtained alumina hydrate was measured with an X-ray diffractometer (X'Pert-PRO, manufactured by PANalytical), and the crystal structure was identified from the angle and intensity of the diffraction profile. The crystal structures of the alumina hydrates A to C were all boehmite.

<Example 1>
70 parts of the previously prepared alumina dispersion A and 30 parts of alumina dispersion C were mixed, and 0.4 parts of boric acid (20% with respect to polyvinyl alcohol) and 4% of polymer compound A (20% aqueous dispersion) were mixed therewith. 3 parts (4% with respect to alumina hydrate), and 40 parts (10% with respect to alumina hydrate) of 5% aqueous solution of polyvinyl alcohol (PVA245, manufactured by Kuraray Co., Ltd.) It stirred until it became uniform with the motor and the coating liquid 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 obtained recording media were subjected to the following evaluations 3 to 8. The results are shown in Tables 4 and 5.

<Evaluation 3: Specific surface area and pore volume of ink receiving layer>
A PET film (Lumirror, manufactured by Nitto Boseki Co., Ltd .: thickness: 224 μm) is used as a support, and the previously prepared coating solution is coated on it with a Mayer bar so that the dry coating amount is 35 g / m ^2. And dried at 110 ° C. for 20 minutes with a blowing constant temperature dryer (FC-610, manufactured by Toyo Seisakusho Co., Ltd.) to form an ink receiving layer. This was cut finely and vacuum deaerated at 80 ° C. for 24 hours, and then measured using a specific surface area / pore distribution measuring device (TriSter3000, manufactured by Micromeritics (Shimadzu Corporation)). Nitrogen was used as the adsorption gas. The specific surface area was determined by the BET method, and the pore volume was determined from the total pore volume of pores having a pore radius of 100 nm or less. The obtained values are shown in Table 4.

Various properties of the obtained recording medium were evaluated in the following manner.
<Evaluation 4: Evaluation Method for Print Density>
A black (Bk) ink, a cyan (C) ink, a magenta (M) ink, and a yellow (Y) ink are monochromatic using the inkjet recording apparatus (BJ F870, manufactured by Canon Inc.) on the recording medium thus prepared. In addition, solid printing was performed at an ink ejection amount of 100%, and the optical density of each color was measured using an optical reflection densitometer (RD-918, manufactured by Greta Macbeth). The obtained values are shown in Table 5.

<Evaluation 5: Evaluation method for ink absorbency>
An ink jet printer (BJ F870, manufactured by Canon Inc.) is used for the produced recording medium, and green (cyan ink / photocyan ink / yellow) is applied within a range of 90% to 270%. The solid ink was printed with an ink mixing ratio of 85/90/100), and the ink absorbency was evaluated by obtaining the maximum driving amount that does not cause beading. An ink ejection amount of 200% or more is indicated by “◯”, an ink ejection amount of 170% or more and less than 200% is indicated by “△”, and an ink ejection amount of less than 170% is indicated by “X”. . The results are shown in Table 5.

<Evaluation 6: Evaluation method for fading / discoloration suppression effect by gas>
Using an ink jet recording apparatus (BJ F870, manufactured by Canon Inc.), a black (Bk) ink and a cyan (C) ink were printed in a single color and solidly printed with an ink ejection amount of 100%. After putting it in a tester (made by Suga Test Instruments Co., Ltd., special order) and exposing it to ozone at a concentration of 1 ppm under the conditions of 40 ° C. and 55% RH, the optical density of Bk and C was measured with an optical reflection densitometer (Greta It was measured using Macbeth Co., Ltd. (RD-918). Next, the remaining OD rate is calculated from the following formula (3). When the remaining OD rate is 80% or more, “◯”, when the remaining OD rate is 60% or more and less than 80%, “△”, the remaining OD rate The evaluation was made with “x” when less than 60%. The results are shown in Table 5.
Residual OD rate = (OD after test / OD before test) × 100% Formula (3)

<Evaluation 7: Evaluation Method for Fading / Discoloration Suppression 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 ejection amount of 100% is performed atlas fade meter (condition: wavelength 340 nm). irradiation intensity 0.39 W / m ^2, temperature 45 ° C. in, poured into 70% humidity), 100 hours after M optical reflection densitometer optical density (Greta Macbeth Co., was measured using a RD-918). Next, the remaining OD rate is calculated from the formula (3). When the remaining OD rate is 90% or more, “◯”, when the remaining OD rate is 80% or more and less than 90%, “△”, and the remaining OD rate is Evaluation was made with less than 80% as “x”. The results are shown in Table 5.

<Evaluation 8: Evaluation method for image bleeding under high humidity>
Using an inkjet recording apparatus (BJ F870, manufactured by Canon Inc.), black (Bk) ink, cyan (C) ink, magenta (M) ink, and yellow (Y) ink are monochromatic and have an ink ejection amount of 100. The above-mentioned recording medium solidly printed in% was exposed for 1 week in an environment of 30 ° C. and 80% RH, and the degree of blurring of the image 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 significantly occurs in any of the colors. The results are shown in Table 5.

<Example 2>
In Example 1, the coating solution was prepared in the same manner as in Example 1 except that the amount of the polymer compound A added was 6 parts (6% with respect to the alumina hydrate). went. Further, a recording medium was produced in the same manner as in Example 1, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Example 3>
In Example 1, the coating solution was prepared in the same manner as in Example 1 except that the amount of the polymer compound A added was 8 parts (8% with respect to the alumina hydrate). went. Further, a recording medium was produced in the same manner as in Example 1, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Example 4>
In Example 1, the coating solution was prepared in the same manner as in Example 1 except that the amount of the polymer compound A added was 10 parts (10% with respect to the alumina hydrate). went. Further, a recording medium was produced in the same manner as in Example 1, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Example 5>
A coating solution was prepared in the same manner as in Example 2 except that 50 parts of the alumina dispersion A and 50 parts of the alumina dispersion C were used. In addition, a recording medium was produced in the same manner as in Example 2, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Example 6>
A coating solution was prepared in the same manner as in Example 2 except that the alumina dispersion C was changed to the alumina dispersion B in Example 2, and a test of Evaluation 3 was performed. In addition, a recording medium was produced in the same manner as in Example 2, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Example 7>
In Example 2, the coating liquid was prepared in the same manner as in Example 2 except that the alumina dispersion C was 100 parts and the alumina dispersion A was not used, and the test of Evaluation 3 was performed. In addition, a recording medium was produced in the same manner as in Example 2, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Example 8 and Example 9>
In Example 1, a coating liquid was prepared in the same manner as in Example 1 except that the polymer compound B (Example 8) and the polymer compound C (Example 9) were used instead of the polymer compound A. The test of evaluation 3 was performed. Further, a recording medium was produced in the same manner as in Example 1, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

< Reference Example 1 >
In Example 1, a coating solution was prepared in the same manner as in Example 1 except that the polymer compound A was not added, and an ink was formed on a PET film (Lumirror, manufactured by Nitto Boseki Co., Ltd .: thickness: 224 μm). A receiving layer was formed. Thereafter, the polymer compound D (10% acetone solution) is overcoated with a Mayer bar on the ink receiving layer so that 10% in terms of solid content is added to the alumina hydrate in the ink receiving layer, and then blown. The ink receiving layer containing the polymer compound D was formed by drying at 110 ° C. for 10 minutes with a constant temperature dryer (manufactured by Toyo Seisakusho, FC-610). (However, the ink receiving layer overcoated with the polymer compound D was adjusted so that its dry weight was 35 g / m ² ).

The test of Evaluation 3 was performed using the PET film having the ink receiving layer formed by the above method. The results are shown in Table 4. Moreover, the PET film was changed to polyethylene-coated paper (manufactured by Oji Paper Co., Ltd .; thickness: 224 μm, basis weight 234 g / m ² ; 60-degree specular gloss according to JIS-Z-8741 was 64%), and Similarly, a recording medium having an ink receiving layer coated with the polymer compound D was prepared, and tests 4 to 8 were performed. The results are shown in Table 5.

<Comparative Example 1>
In Example 1, except that the alumina dispersion A was 100 parts and the alumina dispersion C and the polymer compound A were not used, the coating solution was prepared in the same manner as in Example 1, and the test of Evaluation 3 was performed. went. Further, a recording medium was produced in the same manner as in Example 1, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Comparative example 2>
In Example 1, except that the alumina dispersion A, the alumina dispersion C and the polymer compound A were not used, and the alumina dispersion B was changed to 100 parts instead of the alumina dispersion A and the alumina dispersion C, The coating liquid was adjusted in the same manner as in Example 1, and the test of Evaluation 3 was performed. Further, a recording medium was produced in the same manner as in Example 1, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Comparative Example 3>
In Example 1, except that the alumina dispersion C was 100 parts and the alumina dispersion A and the polymer compound A were not used, the coating solution was prepared in the same manner as in Example 1, and the test of Evaluation 3 was performed. went. Further, a recording medium was produced in the same manner as in Example 1, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Comparative example 4>
In Example 2, the coating liquid was prepared in the same manner as in Example 2 except that the alumina dispersion A was 100 parts and the alumina dispersion C was not used, and the test of Evaluation 3 was performed. In addition, a recording medium was produced in the same manner as in Example 2, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Comparative Example 5>
In Example 3, the coating liquid was prepared in the same manner as in Example 3 except that the alumina dispersion A was 100 parts and the alumina dispersion C was not used, and the test of Evaluation 3 was performed. In addition, a recording medium was produced in the same manner as in Example 3, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Comparative Example 6>
In Example 2, the coating liquid was adjusted in the same manner as in Example 2 except that the alumina dispersion A and the alumina dispersion C were not used, and the alumina dispersion B was 100 parts. went. In addition, a recording medium was produced in the same manner as in Example 2, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Comparative Example 7>
In Example 5, except that the amount of the polymer compound A added was 10 parts (10% with respect to the alumina hydrate), the coating solution was prepared in the same manner as in Example 5, and the test of Evaluation 3 was performed. went. Further, a recording medium was produced in the same manner as in Example 5, and the tests of evaluations 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Comparative Example 8>
In Example 3, except that the alumina dispersion C was changed to the alumina dispersion B, the coating liquid was adjusted in the same manner as in Example 3, and the test of Evaluation 3 was performed. In addition, a recording medium was produced in the same manner as in Example 3, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

<Comparative Example 9>
A coating solution was prepared in the same manner as in Example 4 except that the alumina dispersion C was changed to the alumina dispersion B in Example 4, and a test of Evaluation 3 was performed. In addition, a recording medium was manufactured in the same manner as in Example 4, and tests 4 to 8 were performed. The results are shown in Tables 4 and 5.

As is apparent from the above results, the ink receiving layer contains a polymer compound obtained by reacting a sulfur-containing organic compound, the specific surface area of the ink receiving layer is 75 m ² / g or more, and the ink receiving layer. The recording medium with a pore volume of 0.55 cm ³ / g or more has excellent ink absorption and image density, gas resistance, light resistance, and excellent image bleeding under high temperature and high humidity. ing.

By containing a high molecular compound obtained by reacting a sulfur-containing organic compound in the ink receiving layer, and setting the specific surface area and pore volume of the ink receiving layer to a specific range, it is possible to generate acid by atmospheric air and light. It was possible to produce a recording medium capable of effectively preventing image discoloration and image bleeding under high temperature and high humidity, and capable of high-quality image recording with excellent ink absorbability.

Claims (3)

In a recording medium having an ink receiving layer having a gap on at least one surface of a support, the ink receiving layer comprises a sulfur-containing organic compound (A) having two or more active hydrogen groups and two or more. The polyisocyanate compound (B) having an isocyanate group is reacted with an amine compound (C) having two or more active hydrogen groups, and at least a part of the amino group of the amine compound (C) is cationized with an acid. phased polymer compound, and contains alumina hydrate fine particles as inorganic fine particles, and the ratio measured by the BET method of the ink-receiving layer surface area a (m ² / g) and pore volume V (cm ³ / g) is, A recording medium satisfying the relationship of the following formula (1) and the following formula (2).
75 ≦ A ≦ 92 (Formula 1)
0.55 ≦ V ≦ 2.00 (Formula 2) Said acid, phosphoric acid, phosphorous acid, formic acid, acetic acid, propionic acid, butyric acid, glycolic acid, lactic acid, pyruvic acid, methanesulfonic acid, according to claim 1 Ru least one Der selected from hydrochloric acid and nitric acid Recording medium . The inorganic fine particles has a specific surface area and the recording medium according to claim 1 or 2, wherein at least one of the pore volume is obtained by mixing a plurality of different alumina hydrate fine particles.