JP3861911B2 - Ink jet receiving agent and ink jet recording medium using the same - Google Patents

Description

  The present invention relates to an ink jet receiving agent capable of imparting good ink jet printability to various substrates.

  In recent years, in the industry related to inkjet printing, where the growth is remarkable, the image quality of inkjet printers has been remarkably improved, and it has become possible to obtain images similar to silver halide photographs. Therefore, the ink jet recording medium is required to have ink absorptivity, high color density, blur prevention, gloss and the like for obtaining a high-definition image.

  In addition, ink jet printers are used not only for home use but also for business purposes such as billboards and advertisements. For these uses, printers capable of large format printing called wide format ink jet printers are used. In this type of printer, the amount of ink ejected is much larger than that of household ink jet printers, so that the ink jet recording medium used requires higher ink absorbability than that for home use. Furthermore, printed materials are often posted outdoors for a long time, and are required to have excellent water resistance, durability against gases such as light and ozone, and excellent image storage stability.

  In order to improve the image storability, a method using a pigment ink in which a coloring material of an ink-jet ink that has conventionally been a dye is replaced with a pigment has been adopted as an improvement means from the ink. Initially, pigment ink was used only for commercial wide format ink jet printers, but in recent years, pigment ink has also been adopted for some models of home inkjet printers.

  Incidentally, water-based inks are generally used for ink jet printers. In general, an ink jet recording medium is composed of, for example, a water-soluble resin such as polyvinyl alcohol or polyvinyl pyrrolidone, or an ink jet receiving agent using various additives in order to prevent bleeding of such aqueous ink or to improve ink absorbability. An ink jet receiving layer is provided on a substrate such as paper or plastic film.

  However, the ink-jet receiving layer that has been widely used has been developed for dye ink, which has been the mainstream than before, and in the case of using pigment ink whose usage is increasing in recent years, In other words, the ink cannot be applied to the printing of pigment ink. For example, the ink is not sufficiently absorbed, causes blurring, and cracks occur in an image portion where the amount of ink is large, so that a uniform image cannot be obtained. Further, as described above, since water-based ink is used in ink jet printing, there is a problem that an image printed with an ink jet printer has poor water resistance, and various attempts have been made to improve water resistance.

  The most commonly performed improvement in water resistance is a method using an ink-jet receiving agent in which a water-soluble cationic resin such as polydiallyldimethylammonium chloride is contained in a water-soluble resin such as polyvinyl alcohol or polyvinylpyrrolidone. . This is because the cationic group in the molecule of the water-soluble cationic resin is electrostatically bonded to the anionic group in the colorant (dye, pigment) molecule in the water-based ink, thereby fixing the colorant of the water-based ink. It improves water resistance. Although the water resistance is improved to some extent by this method, since the water-soluble cationic resin itself is easily dissolved in water, the water resistance improvement effect is insufficient. In addition, such an ink jet receiving layer has poor printability of pigment ink, and is not at a level that can be used as an ink jet receiving layer for pigment ink.

  On the other hand, as an inkjet recording medium having a high ink absorption speed and excellent quick drying properties, a number of inkjet recording media, called microporous and void types, provided with an inkjet receiving layer containing a large amount of porous inorganic fine particles have been proposed. ing. For example, a glossy sheet containing a recording sheet (for example, see Patent Document 1) provided with an ink jet receiving layer containing pseudoboehmite type alumina, silica and aluminum compound produced by a vapor phase method, and the like. And an ink jet recording sheet provided with an ink jet receiving layer having excellent water resistance (see, for example, Patent Document 2).

  These ink jet receiving layers have innumerable fine voids, and these voids allow printing by absorbing the solvent of the ink. However, since there is a limit to the amount of voids, when printing with a printer with a large amount of ink discharge, such as a wide format ink jet printer that uses a lot of pigment ink, the ink will not be able to absorb and the ink will overflow. Therefore, there is a problem that a good printed matter cannot be obtained.

  In addition, since these ink jet receiving layers contain a large amount of inorganic fine particles, fine cracks are likely to occur on the coated surface when the ink jet receiving agent is coated on the substrate and dried. For this reason, it is necessary to dry at a low temperature, or to coat several times with a thickness that does not cause cracks, and there is a problem that the production efficiency is remarkably poor.

  For this reason, there has been a strong demand for the development of an ink jet receiving agent that provides an ink jet receiving layer that is excellent in printability and absorbability for pigment inks and has good water resistance of printed images, and that has good production efficiency of ink jet recording media.

JP-A-2-276670 JP 2000-309157 A

  An object of the present invention is to provide an ink jet receiving agent that provides an ink jet receiving layer that is excellent in printability and absorptivity for pigment ink and has good water resistance of printed images.

  The present inventors make use of the water-soluble resin typified by polyvinyl alcohol, which has been conventionally used in inkjet receivers, and use other resins having excellent water resistance in combination with these water-soluble resins. Therefore, earnestly proceeded with a policy of improving the water resistance, which is the above-mentioned problem.

  As a result, a polyurethane resin having a cationic group in the side chain obtained by introducing a tertiary amino group having a specific structure into the side chain of the polyurethane resin and neutralizing with an acid or quaternizing with a quaternizing agent. Has excellent dispersion stability in water, and the polyurethane resin film obtained by applying the cationic polyurethane resin aqueous dispersion on a substrate such as a plastic film and drying it is extremely excellent. And found to have water resistance.

  As a result of further investigations, the polyurethane resin film obtained by applying the cationic polyurethane resin aqueous dispersion on a base material such as a plastic film and drying it has excellent water resistance. I found it.

  Furthermore, an inkjet receiving layer containing the cationic polyurethane resin aqueous dispersion, a water-soluble resin, and a water-soluble polyvalent metal salt is applied to a substrate, and an aqueous medium is volatilized to form an inkjet receiving layer. It has also been found that an ink jet recording medium obtained by forming on a material is excellent in printability and absorptivity with respect to pigment ink, and water resistance of a printed image is extremely good.

  That is, the present invention relates to an aqueous medium, a cationic polyurethane resin (B) containing the structural unit (A) represented by the general formula [I] dispersed in the aqueous medium, a water-soluble resin (C), The content of the cationic amino group contained in the structural unit (A) in the cationic polyurethane resin (B) is 0.005 to 1.5 equivalents. Inkjet acceptor, which is / kg.

[Wherein, R ₁ represents an alkylene group that may contain an aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene group, and R ₂ and R ₃ independently represent an aliphatic group. An alkyl group which may contain a cyclic structure, R ₄ represents a hydrogen atom or a residue of a quaternizing agent introduced by a quaternization reaction, and X ⁻ represents an anionic counter ion. ]

  Furthermore, the present invention provides an ink jet recording medium in which an ink jet receiving layer is formed on the substrate by volatilizing the aqueous medium after coating or impregnating the ink jet receiving agent on the substrate. It is.

  The ink jet receiving agent of the present invention can provide an ink jet recording medium which is excellent in printability and absorptivity for pigment ink and has good printed image water resistance.

  The inkjet acceptor of the present invention includes an aqueous medium, a cationic polyurethane resin (B) dispersed in the aqueous medium and containing the structural unit (A) represented by the general formula [I] in the molecule, and a water-soluble resin. (C), a water-soluble polyvalent metal salt (D), and other components as necessary, and a cationic amino contained in the structural unit (A) in the cationic polyurethane resin (B) The group content is 0.005 to 1.5 equivalent / kg.

  First, the aqueous medium constituting the ink jet receiving agent of the present invention is water and an organic solvent miscible with water. Examples of organic solvents miscible with water include alcohols such as methanol, ethanol, n- and isopropanol; ketones such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol and propylene glycol; Alkyl ethers; lactams such as N-methyl-2-pyrrolidone, etc. can be used. In the present invention, only water may be used, or a mixture of water and an organic solvent miscible with water may be used, or only an organic solvent miscible with water may be used. From the viewpoint of safety and environmental load, water alone or a mixture of water and an organic solvent miscible with water is preferred, and water alone is particularly preferred.

Next, the cationic polyurethane resin (B) used in the present invention will be described.
The cationic polyurethane resin (B) used in the present invention contains a structural unit (A) represented by the following general formula [I] in the molecule, and the cationic amino resin contained in the structural unit (A). A group is contained in the cationic polyurethane resin (B) in an amount of 0.005 to 1.5 equivalent / kg.

[Wherein, R ₁ represents an alkylene group that may contain an aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene group, and R ₂ and R ₃ independently represent an aliphatic group. An alkyl group which may contain a cyclic structure, R ₄ represents a hydrogen atom or a residue of a quaternizing agent introduced by a quaternization reaction, and X ⁻ represents an anionic counter ion. ]

  The structural unit (A) represented by the general formula [I] imparts dispersibility to an aqueous medium to the cationic polyurethane resin (B) constituting the present invention, thereby fixing the inkjet ink and the water resistance of the printed image. It is an essential structural unit for improving

  The cationic polyurethane resin (B) used in the present invention can be produced using a known compound. As a production method using an industrially easily available and inexpensive raw material, the following general formula [IV A tertiary amino group-containing polyol (E) obtained by reacting a compound (A-1) having two epoxy groups in one molecule with a secondary amine (A-2), The method of reacting with isocyanate (G) is most useful.

[Wherein, R ₁ represents an alkylene group which may include an aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene group. ]

The tertiary amino group-containing polyol (E) introduces a neutral salt of a tertiary amino group for imparting water dispersibility to the polyurethane resin or a cationic group such as a quaternary amino group into the side chain of the polyurethane resin skeleton. It is a compound used for
The tertiary amino group-containing polyol (E) is a precursor for generating a cationic group by neutralizing the tertiary amino group contained in the molecule with an acid or quaternizing with a quaternizing agent. is there.

  The tertiary amino group-containing polyol (E) includes, for example, a compound (A-1) having two epoxy groups in one molecule and a secondary amine (A-2) with NH equivalent to one equivalent of epoxy group. It can be easily obtained by blending so as to be 1 equivalent of a group and performing a ring-opening addition reaction at room temperature or under heating without using a catalyst.

  As the compound (A-1) having two epoxy groups in one molecule represented by the general formula [IV], the following compounds may be used alone or in combination of two or more.

Examples of the group in which R ₁ is an alkylene group which may contain an aliphatic cyclic structure include ethanediol-1,2-diglycidyl ether, propanediol-1,2-diglycidyl ether, propanediol- 1,3-diglycidyl ether, butanediol-1,4-diglycidyl ether, pentanediol-1,5-diglycidyl ether, 3-methyl-pentanediol-1,5-diglycidyl ether, neopentyl glycol-di Of glycidyl ether, hexanediol-1,6-diglycidyl ether, polybutadiene-diglycidyl ether, cyclohexane-1,4-diglycidyl ether, 2,2-bis (4-hydroxycyclohexyl) -propane (hydrogenated bisphenol A) Diglycidyl ether, hydrogen Diglycidyl ether of (hydrogenated bisphenol F), which is an isomer mixture of added dihydroxydiphenylmethane, can be used.

Examples of those in which R ₁ is a residue of a dihydric phenol include, for example, resorcinol-diglycidyl ether, hydroquinone-diglycidyl ether, 2,2-bis (4-hydroxyphenyl) -propane (bisphenol A) Diglycidyl ether, diglycidyl ether of isomer mixture of dihydroxydiphenylmethane (bisphenol F), diglycidyl ether of 4,4-dihydroxy-3-3'-dimethyldiphenylpropane, diglycidyl ether of 4,4-dihydroxydiphenylcyclohexane, 4 , 4-dihydroxydiphenyl diglycidyl ether, 4,4-dihydroxydibenzophenone diglycidyl ether, bis (4-hydroxyphenyl) -1,1-ethane diglycidyl ether, bis (4-hydroxy Phenyl) -1,1-isobutane diglycidyl ether, bis (4-hydroxy-3-tert-butylphenyl) -2,2-propane diglycidyl ether, bis (2-hydroxynaphthyl) methane diglycidyl ether, Diglycidyl ether of bis (4-hydroxyphenyl) sulfone (bisphenol S) or the like can be used.

Examples of the group in which R ₁ is a polyoxyalkylene group include diethylene glycol-diglycidyl ether, dipropylene glycol-diglycidyl ether, and polyoxyalkylene glycol-diglycidyl ether having 3 to 60 repeating units of oxyalkylene. For example, polyoxyethylene glycol-diglycidyl ether and polyoxypropylene glycol-diglycidyl ether, diglycidyl ether of ethylene oxide-propylene oxide copolymer, polyoxytetraethylene glycol-diglycidyl ether, etc. can be used. .

Among these, since the water dispersibility of the cationic polyurethane resin can be further improved, the diglycidyl ether of polyoxyalkylene glycol in which R _{1 in the} general formula [IV] is a polyoxyalkylene group, Oxyethylene glycol-diglycidyl ether and / or polyoxypropylene glycol-diglycidyl ether and / or diglycidyl ether of ethylene oxide-propylene oxide copolymer are preferred.

The epoxy equivalent of diglycidyl ether of polyoxyalkylene glycol in which R _{1 in the} general formula [IV] is a polyoxyalkylene group affects the physical properties such as various mechanical properties and thermal properties of the ink jet receiving agent of the present invention. Is preferably 1000 g / equivalent or less, more preferably 500 g / equivalent or less, particularly preferably 300 g / equivalent or less, in that the cation concentration in the cationic polyurethane resin aqueous dispersion can be designed over a wide range. is there.

  In the present invention, in order to produce a tertiary amino group-containing polyol (E) by a ring-opening addition reaction with a compound (A-1) having two epoxy groups in one molecule, a secondary amine (A-2 )is required.

As the secondary amine (A-2), a known compound can be used, but a branched or linear aliphatic secondary amine is preferable from the viewpoint of easy reaction control.
Examples of such secondary amine that can be used include dimethylamine, diethylamine, di-n-propylamine, diisopropylamine, di-n-butylamine, di-tert-butylamine, di-sec-butylamine, di-n. -Pentylamine, di-n-peptylamine, di-n-octylamine, diisooctylamine, dinonylamine, diisononylamine, di-n-decylamine, di-n-undecylamine, di-n-dodecylamine, di- Examples include n-pentadecylamine, di-n-octadecylamine, di-n-nonadecylamine, and di-n-eicosylamine.

  Among these, it is difficult to volatilize when producing the tertiary amino group-containing polyol (E), or part or all of the tertiary amino group contained is neutralized with an acid, or 4 with a quaternizing agent. For reasons such as the ability to reduce steric hindrance when classifying, an aliphatic secondary amine having 2 to 18 carbon atoms is preferred, and an aliphatic secondary amine having 3 to 8 carbon atoms is more preferred.

  A tertiary amino group-containing polyol (E) is obtained by neutralizing part or all of the tertiary amino group of the tertiary amino group-containing polyol (E) with an acid or quaternizing with a quaternizing agent. Water dispersibility can be imparted to the cationic polyurethane resin (B) obtained by reacting with the polyisocyanate (G).

  Examples of the acid that can be used for neutralizing part or all of the tertiary amino group include formic acid, acetic acid, propionic acid, succinic acid, glutaric acid, butyric acid, lactic acid, malic acid, and citric acid. , Organic acids such as tartaric acid, malonic acid, adipic acid, organic sulfonic acids such as sulfonic acid, paratoluenesulfonic acid, methanesulfonic acid, and hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, phosphorous acid, hydrofluoric acid Inorganic acids such as can be used. These acids may be used alone or in combination of two or more.

Examples of the quaternizing agent that can be used for quaternizing a part or all of the tertiary amino group include dialkyl sulfates such as dimethyl sulfate and diethyl sulfate, methyl chloride, and ethyl chloride. Alkyl halides such as benzyl chloride, methyl bromide, ethyl bromide, benzyl bromide, methyl iodide, ethyl iodide, benzyl iodide, and alkyl or aryl sulfonates such as methyl methanesulfonate and methyl paratoluenesulfonate Epoxy such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, allyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, and phenyl glycidyl ether It is possible to use kind and the like.
These may be used alone or in combination of two or more.

  In the present invention, the amount of acid or quaternizing agent used for neutralization or quaternization of the tertiary amino group is not particularly limited, but the ink-jet receiving agent of the present invention exhibits excellent water resistance of the printed image. Therefore, it is preferably in the range of 0.1 to 3 equivalents, more preferably in the range of 0.3 to 2.0 equivalents with respect to 1 equivalent of the tertiary amino group.

  In the ink jet receiving agent of the present invention, the cationic polyurethane resin (B) is quaternized with a tertiary amino group from the viewpoint that the fixing property of the ink jet ink is excellent, and as a result, the water resistance of the printed image is further improved. It is more preferable.

A method for reacting the compound (A-1) having two epoxy groups in one molecule with the secondary amine (A-2) for obtaining the tertiary amino group-containing polyol (E) will be described below.
The reaction ratio [NH group / epoxy group] of the epoxy group of the compound (A-1) having two epoxy groups in one molecule and the NH group of the secondary amine (A-2) is preferably equivalent. The ratio is in the range of 0.5 / 1 to 1.1 / 1, more preferably the equivalent ratio is in the range of 0.9 / 1 to 1/1.

  These reactions can be carried out under solvent-free conditions, but can also be carried out using an organic solvent for the purpose of facilitating the reaction control, or for the purpose of reducing the stirring load due to a decrease in viscosity or causing a uniform reaction. .

  Such an organic solvent may be any organic solvent that does not inhibit the reaction. For example, ketones, ethers, acetate esters, hydrocarbons, chlorinated hydrocarbons, amides, and nitriles can be used. .

As said ketones, acetone, diethyl ketone, methyl ethyl ketone, methyl isobutyl ketone etc. can be used, for example.
Examples of ethers that can be used include diethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, tetrahydrofuran, and dioxane.

Examples of the acetates include ethyl acetate, butyl acetate, propyl acetate and the like.
As hydrocarbons, n-pentane, n-hexane, cyclohexane, n-heptane, benzene, toluene, xylene and the like can be used.
As chlorinated hydrocarbons, for example, carbon tetrachloride, dichloromethane, chloroform, trichloroethane and the like can be used.
Examples of amides that can be used include dimethylformamide, and examples of nitriles include N-methylpyrrolidone and acetonitrile.

  Among the organic solvents described above, when an organic solvent having a low boiling point is used, it is preferable to perform a pressure reaction in a closed system in order to prevent scattering due to volatilization.

  The compound having two epoxy groups in one molecule (A-1) and the secondary amine (A-2) may be supplied together in a reaction vessel and reacted, and an epoxy group is contained in one molecule. Any one of the two compounds (A-1) and the secondary amine (A-2) may be charged into a reaction vessel and the other may be dropped.

  Since the reaction between the compound (A-1) having two epoxy groups in one molecule and the secondary amine (A-2) is highly reactive, it usually does not require a catalyst. However, when the secondary amine (A-2) has a large substituent such as an aliphatic nitrogen atom, and the reaction with the compound (A-1) is slowed by steric hindrance, phenol, acetic acid, water A proton donating substance typified by alcohols may be used as a catalyst.

The reaction temperature is preferably in the range of room temperature to 160 ° C, more preferably in the range of 60 to 120 ° C.
The reaction time is not particularly limited, but is usually in the range of 30 minutes to 14 hours.
The end point of the reaction can be confirmed by disappearance of the absorption peak near 842 cm ⁻¹ due to the epoxy group by infrared spectroscopy (IR method).
Moreover, an amine equivalent (g / equivalent) and a hydroxyl equivalent (g / equivalent) can be calculated | required by a conventional method.

  When producing the cationic polyurethane resin (B), in addition to the tertiary amino group-containing polyol (E), various polyols (F) generally used for synthesis of polyurethane depending on the purpose and application. Can be used.

  Among them, the polyester polyol, polyether polyol, carbonic acid and aliphatic polyhydric alcohol having a number average molecular weight of 200 to 10,000, more preferably a number average molecular weight of 300 to 5,000 are preferably esterified. Various polyols such as polycarbonate polyol, polyesteramide polyol, polyacetal polyol, polythioether polyol, and polybutadiene glycol polyol obtained by the above-mentioned method may be used, and these may be used alone or in combination of two or more.

  Among the polyols (F), representative compounds are exemplified below for polyester polyols, polyether polyols, and polycarbonate polyols that are industrially easily available.

  As said polyester polyol, what is obtained by esterifying a low molecular weight polyol and polycarboxylic acid can be used.

  Examples of the low molecular weight polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, and 3-methyl-1,5. -Pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, polyethylene glycol (Number average molecular weight 300-6000 range), polypropylene glycol (number average molecular weight 300-6000 range), ethylene oxide-propylene oxide copolymer (number average molecular weight 300-6000) Circumference); bisphenol A, hydrogenated bisphenol A and alkylene oxide adducts thereof; trimethylolpropane, trimethylolethane, pentaerythritol, it can be used sorbitol.

  Examples of the polycarboxylic acid that can be used in producing the polyester polyol include succinic acid, adipic acid, azelaic acid, sebacic acid, todecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane p, p′-dicarboxylic acid, trimellitic acid, pyromellitic acid, and anhydrides or ester-forming derivatives of these polycarboxylic acids can be used.

  Moreover, as said polyester polyol, polyester obtained by ring-opening polymerization reaction of cyclic ester compounds, such as (epsilon) -caprolactone, these copolyesters, etc. can also be used.

  Further, as the polyether polyol, for example, a compound having at least two active hydrogen atoms described later is used as an initiator, and a compound such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, cyclohexylene, etc. What is obtained by addition-polymerizing 1 or more types can be used.

  Examples of the compound having at least two active hydrogen atoms include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, and hexamethylene glycol. , Sucrose, methylene glycol, glycerin, sorbitol; actinic acid, trimellitic acid, hemimellitic acid, phosphoric acid, ethylenediamine, propylenediamine, diethylenetriamine, triisopropanolamine, pyrogallol, dihydrobenzoic acid, hydroxyphthalic acid, 1,2,3 -Propane trithiol or the like can be used.

  Examples of the polycarbonate polyol obtained by esterifying carbonic acid with an aliphatic polyhydric alcohol include 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and polyethylene. Reaction products of diols such as glycol, polypropylene glycol or polytetramethylene glycol (PTMG) and cyclic carbonates such as dimethyl carbonate and ethylene carbonate Is mentioned.

  In addition to the water resistance of the polyurethane resin film and the fixing property and water resistance of the inkjet ink, the ink jet receiving agent of the present invention is required to have light resistance and weather resistance because it is used outdoors in advertising banners and the like. On the other hand, printed materials such as photographs and paintings are required to have long-term storage durability.

  In this case, among the polyols (F), since it is preferable to use a highly durable polyol, by using a polycarbonate polyol obtained by esterifying a carbonic acid and an aliphatic polyhydric alcohol. It is preferable to introduce a structural unit derived from a polycarbonate polyol into the cationic polyurethane resin (B).

  Examples of the polyisocyanate (G) that can be used in producing the cationic polyurethane resin (B) of the present invention include aqueous polyurethane resins such as aromatic polyisocyanates, alicyclic polyisocyanates, and aliphatic polyisocyanates. And known organic polyisocyanates used in the production of

  Examples of the aromatic polyisocyanate include 1,3- and 1,4-phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate (2,4-TDI), and 1-methyl-2,6-phenylene diisocyanate. (2,6-TDI), 1-methyl-2,5-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene Diisocyanate, 1-isopropyl-propyl-2,4-phenylene diisocyanate, 1,3-dimethyl-2,4-phenylene diisocyanate, 1,3-dimethyl-4,6-phenylene diisocyanate, 1,4-dimethyl-2,5 -Phenylene diisocyanate, diethylbenzene diisocyanate ,

Diisopropylbenzene diisocyanate, 1-methyl-3,5-diethylbenzene diisocyanate, 3-methyl-1,5-diethylbenzene-2,4-diisocyanate, 1,3,5-triethylbenzene-2,4-diisocyanate, naphthalene-1, 4-diisocyanate, naphthalene-1,5-diisocyanate, 1-methyl-naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate, 1,1-dinaphthyl-2,2 ′ Diisocyanate, biphenyl-2,4′-diisocyanate, biphenyl-4,4′-diisocyanate, 3-3′-dimethylbiphenyl-4,4′-diisocyanate, diphenylmethane-4,4′-diisocyanate (4,4-MDI ) Diphenylmethane-2,2'-diisocyanate (2,2-MDI), it may be used diphenylmethane-2,4-diisocyanate (2,4-MDI) and the like.

  Examples of the alicyclic polyisocyanate and aliphatic polyisocyanate include tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di (isocyanate methyl) cyclohexane, 1,4-di (isocyanate methyl) cyclohexane, lysine diisocyanate, isophorone diisocyanate (IPDI), 4,4 '-Dicyclohexylmethane diisocyanate (4,4H-MDI), 2,4'-dicyclohexylmethane diisocyanate (2,4-H-MDI), 2 2'-dicyclohexylmethane diisocyanate (2,2-H-MDI), 3,3'- dimethyl-4,4'-dicyclohexylmethane diisocyanate and these trimers and the like can be used.

  Since it is relatively inexpensive and easy to obtain raw materials, 1-methyl-2,4-phenylene diisocyanate (2,4-TDI), 1-methyl-2,6-phenylene diisocyanate (2,6-TDI), XDI such as 1,3-dimethyl-2,4-phenylene diisocyanate, 1,3-dimethyl-4,6-phenylene diisocyanate, 1,4-dimethyl-2,5-phenylene diisocyanate, diphenylmethane-4,4′-diisocyanate (4,4-MDI), diphenylmethane-2,2′-diisocyanate (2,2-MDI), diphenylmethane-2,4-diisocyanate (2,4-MDI), 1,6-hexamethylene diisocyanate (HDI), Isophorone diisocyanate (IPDI), 4,4'-dicyclohexylmethane dii Cyanate (4,4-H-MDI), 2,4'- dicyclohexylmethane diisocyanate (2,4-H-MDI), 2,2'- dicyclohexylmethane diisocyanate (2,2-HDI) is preferable.

  In addition to the water resistance of the polyurethane resin film, the fixing property and water resistance of the inkjet ink, the ink jet receiving agent of the present invention is required to have light resistance and weather resistance because it is used outdoors in advertising banners, etc. Long-term storage durability is required for printed materials such as photographs and paintings.

  In that case, in order to prevent deterioration of the surface appearance due to heat discoloration and light discoloration, an alicyclic polyisocyanate and / or an aliphatic polyisocyanate generally referred to as non-yellowing type is used as the polyisocyanate, thereby cationic polyurethane. It is preferable to introduce a structural unit derived from the alicyclic polyisocyanate and / or aliphatic polyisocyanate according to the resin (B).

  In addition, as the polyisocyanate (G), considering the availability of raw materials, 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate (4,4 -H-MDI), 2,4'-dicyclohexylmethane diisocyanate (2,4-H-MDI), 2,2'-dicyclohexylmethane diisocyanate (2,2-HDI) are particularly preferred.

  When the cationic polyurethane resin (B) is produced, polyamine may be used as a chain extender for the purpose of designing a polyurethane resin having physical properties such as various mechanical properties and thermal properties.

  Examples of the polyamine that can be used as the chain extender include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, and 4,4′-dicyclohexylmethane. Diamines such as diamine, 3,3′-dimethyl-4,4′-dicyclohexylmethanediamine, 1,4-cyclohexanediamine; hydroxymethylaminoethylamine, hydroxyethylaminoethylamine, hydroxypropylaminopropylamine, ethylaminoethylamine, methyl Diamines containing one primary amino group and one secondary amino group, such as aminopropylamine;

Polyamines such as diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazines such as hydrazine, N, N′-dimethylhydrazine, 1,6-hexamethylenebishydrazine; succinic dihydrazide, adipic dihydrazide, glutaric dihydrazide, sebacine Dihydrazides such as acid dihydrazide and isophthalic acid dihydrazide; semicarbazides such as β-semicarbazide propionic acid hydrazide, 3-semicarbazide-propyl-carbazate, semicarbazide-3-semicarbazidemethyl-3,5,5-trimethylcyclohexane Can be used.

  When the cationic polyurethane resin (B) is produced, in addition to the polyamine, other chain extenders containing active hydrogen atoms are used for the purpose of adjusting physical properties such as various mechanical properties and thermal properties of the polyurethane resin. Can also be used.

  Examples of the other active hydrogen-containing chain extenders include ethylene glycol, diethylene recall, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1, Glycols such as 4-butanediol, hexamethylene glycol, saccharose, methylene glycol, glycerin, sorbitol; bisphenol A, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenylsulfone, Examples thereof include hydrogenated bisphenol A, phenols such as hydroquinone, and water, and these may be used alone or in combination within a range not deteriorating the storage stability of the cationic polyurethane resin aqueous dispersion of the present invention. There.

  Examples of the method for producing the cationic polyurethane resin (B) used in the present invention and dispersing the cationic polyurethane resin (B) in the aqueous medium include the following methods.

[Method 1] A polyurethane resin is produced by charging a polyol (F), a polyisocyanate (G), and a tertiary amino group-containing polyol (E) all at once or separately and reacting them in a solvent or in the absence of a solvent. A method in which part or all of the tertiary amino groups in the obtained polyurethane resin are neutralized with an acid and / or quaternized with a quaternizing agent, and then water is added to disperse in water.

[Method 2] A polyol (F), a polyisocyanate (G), and a tertiary amino group-containing polyol (E) are charged all at once or separately and reacted in a solvent or in the absence of a solvent to form an isocyanate group at the terminal. After producing a urethane prepolymer having a polyurethane resin, a polyurethane resin is produced by chain extension using a polyamine, and some or all of the tertiary amino groups in the obtained polyurethane resin are neutralized with an acid, and / or 4 A method in which water is added and dispersed after quaternization with a classifier.

[Method 3] A polyol (F), a polyisocyanate (G), and a tertiary amino group-containing polyol (E) are charged all at once or separately, and reacted in a solvent or in the absence of a solvent to form an isocyanate group at the terminal. The urethane prepolymer is produced, and part or all of the tertiary amino groups in the obtained urethane prepolymer are neutralized with an acid and / or quaternized with a quaternizing agent, and then water is added thereto. A method in which water is dispersed and then chain elongation is performed using polyamine.

[Method 4] Polyol (F), polyisocyanate (G), and tertiary amino group-containing polyol (E) are batched or divided and charged, and reacted in a solvent or in the absence of a solvent to react with isocyanate at the end. After producing a urethane prepolymer having a group and neutralizing a part or all of the tertiary amino group with an acid and / or quaternizing with a quaternizing agent, using a machine such as a homogenizer in an aqueous medium A method of forcibly emulsifying and dispersing in water, followed by chain elongation using polyamine.

[Method 5] A polyurethane resin is produced by charging a polyol (F), a polyisocyanate (G), a tertiary amino group-containing polyol (E) and a polyamine in a lump and reacting them in a solvent or without a solvent. A method in which part or all of the tertiary amino groups in the obtained polyurethane resin are neutralized with an acid and / or quaternized with a quaternizing agent, and then water is added to disperse in water.

  In addition, in the manufacturing method of said [Method 1]-[Method 5], you may use an emulsifier as needed.

  The emulsifier that can be used in producing the cationic polyurethane resin aqueous dispersion (B) is not particularly limited, but is fundamental from the viewpoint of maintaining the excellent storage stability of the cationic polyurethane resin aqueous dispersion. It is preferably nonionic or cationic. For example, nonionic emulsifiers such as polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene sorbitol tetraoleate, polyoxyethylene / polyoxypropylene copolymer; alkylamine salts, It is preferable to use cationic emulsifiers such as alkyltrimethylammonium salts and alkyldimethylbenzylammonium salts. An anionic or amphoteric emulsifier may be used in combination as long as the mixing stability of the emulsifier to the cationic polyurethane resin aqueous dispersion is maintained.

  When the cationic polyurethane resin (B) is produced by the above-described method, a compound having a group capable of becoming a hydrophilic group (hereinafter referred to as a hydrophilic group-containing compound) is used as an aid for assisting the water dispersibility of the resin. May be.

  As such a hydrophilic group-containing compound, an anionic group-containing compound, a cationic group-containing compound, an amphoteric group-containing compound, or a nonionic group-containing compound can be used, but the excellent storage stability of the cationic polyurethane resin aqueous dispersion is excellent. From the viewpoint of maintaining the properties, a nonionic group-containing compound is preferable.

  The nonionic group-containing compound includes a group having at least one active hydrogen atom in the molecule and consisting of a repeating unit of ethylene oxide, and a group consisting of a repeating unit of ethylene oxide and another repeating unit of alkylene oxide. A compound having at least one functional group selected from the group can be used.

  For example, polyoxyethylene glycol or polyoxyethylene-polyoxypropylene having a number average molecular weight of 300 to 20,000 containing at least 30% by mass of repeating units of ethylene oxide and containing at least one active hydrogen atom in the polymer Nonionic group-containing compounds such as copolymer glycols, polyoxyethylene-polyoxybutylene copolymer glycols, polyoxyethylene-polyoxyalkylene copolymer glycols or monoalkyl ethers thereof, or polyester polys obtained by copolymerizing these It is possible to use compounds such as ether polyols.

  Next, the raw material charging ratio (equivalent ratio) when producing the cationic polyurethane resin (B) will be described in detail.

  When the polyol (F), the tertiary amino group-containing polyol (E), and the polyisocyanate (G) are reacted, the equivalent ratio of the isocyanate group and the active hydrogen atom-containing group [equivalent of the isocyanate group possessed by (G)] / [Equivalent hydroxyl group of (F) + Equivalent hydroxyl group of (E)] is preferably adjusted to a range of 0.9 / 1 to 1.1 / 1.

  When the cationic polyurethane resin (B) is produced, for example, when a polyamine is used as a chain extender, the equivalent ratio of isocyanate group to active hydrogen atom-containing group [(equivalent of isocyanate of (G)] / [(F The equivalent of the hydroxyl group possessed by (E) + the equivalent of the hydroxyl group possessed by (E) + the equivalent of the amino group possessed by the polyamine] is preferably adjusted in the range of 0.9 / 1 to 1.1 / 1.

  Moreover, you may manufacture the said cationic polyurethane resin (B) by making chain | strand extension reaction using a polyamine, after manufacturing a urethane prepolymer. In such a case, the equivalent ratio of isocyanate group to active hydrogen atom-containing group [equivalent of isocyanate group possessed by (G)] / [equivalent hydroxyl group possessed by (F) + equivalent hydroxyl group possessed by (E)] It is preferable to adjust to the range of 1/1 to 3/1, and it is more preferable to adjust to the range of 1.2 / 1 to 2/1. In this case, the equivalent ratio of the amino group and excess isocyanate group of the polyamine when chain-extending with the polyamine is preferably in the range of 1.1 / 1 to 0.9 / 1.

  In such a reaction, the reaction temperature is preferably in the range of 20 to 120 ° C, more preferably in the range of 30 to 100 ° C.

  The tertiary amino group-containing polyol (E) is a tertiary amino group-containing polyol (E) and a polyisocyanate (G) or a tertiary amino group-containing polyol in order to exhibit excellent water resistance of a printed image. Preferably it is the range of 0.005-1.5 equivalent / kg with respect to the total amount of (E), polyisocyanate (G), and polyamine, More preferably, it is 0.03-1.0 equivalent / kg. Yes, even more preferably in the range of 0.15 to 0.5 equivalent / kg.

The cationic polyurethane resin (B) can be produced under solvent-free conditions, but for the purpose of facilitating the reaction control, or for the purpose of reducing the stirring load due to a decrease in viscosity or causing a uniform reaction, under an organic solvent. It is also possible to manufacture with.
Examples of the organic solvent include ketones such as acetone, diethyl ketone, methyl ethyl ketone, and methyl isobutyl ketone; ethers such as diethyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol dibutyl ether, tetrahydrofuran, and dioxane; ethyl acetate Acetic esters such as butyl acetate and propyl acetate; Nitriles such as acetonitrile; Hydrocarbons such as n-pentane, n-hexane, cyclohexane, n-heptane, benzene, toluene and xylene; Carbon tetrachloride, dichloromethane and chloroform Chlorinated hydrocarbons such as trichloroethane; amides such as dimethylformamide and N-methylpyrrolidone can be used.

  The cationic polyurethane resin (B) can be produced without a catalyst, but known catalysts such as stannous octylate, dibutyltin dilaurate, dibutyltin dimaleate, dibutyltin diphthalate, dibutyltin dimethoxide Tin compounds such as dibutyltin diacetylacetate and dibutyltin diversate, titanate compounds such as tetrabutyl titanate, tetraisopropyl titanate and triethanolamine titanate, other tertiary amines, quaternary ammonium salts and the like may be used.

  The organic solvent contained in the cationic polyurethane resin aqueous dispersion obtained as described above is preferably removed by, for example, a method such as heating under reduced pressure during the reaction or after the completion of the reaction.

Next, the water-soluble resin (C) will be described.
The water-soluble resin refers to a resin that can take a form completely dissolved in water. Specific examples thereof include polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetal, polyalkylene oxide, starch, methyl cellulose, hydroxy cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, cellulose derivatives such as carboxymethyl cellulose, polyethyleneimine, polyamide, various fourths. Examples thereof include water-soluble resins containing a quaternary ammonium base, and modified products thereof.
Of these, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetal, polyalkylene oxide, and cellulose derivatives are preferable from the viewpoint of good ink absorbability.

  Polyvinyl alcohol, in particular, has the necessary physical properties for ink jet receivers, such as transparency, film strength, and binder power to pigments, and is readily available and has many types including modified products. Is particularly preferred. That is, when polyvinyl alcohol is used as the water-soluble resin (C), an ink jet receiving layer excellent in gloss, transparency and ink absorbability can be provided.

  Polyvinyl alcohol is generally obtained by hydrolyzing an acetyl group portion of a vinyl acetate polymer with a strong base such as sodium hydroxide to form a hydroxyl group (saponification). As a commercially available product of polyvinyl alcohol, there are polyvinyl alcohols having various saponification ratios (saponification degrees) and polymerization degrees. Among these, those having an appropriate degree of saponification and degree of polymerization can be used according to the required physical properties.

  The saponification degree of polyvinyl alcohol is preferably 80 to 100% from the viewpoints of solubility of polyvinyl alcohol in water and ink absorbability when used in an ink jet receiving agent. A saponification degree of 95% or more is preferred because the pigment ink absorbability is better. Furthermore, it is particularly preferable that the saponification degree is 99% or more from the viewpoint that the color density of the image printed with the pigment ink becomes better.

  Also, from the viewpoint of water resistance of the printed image, it is preferable that the saponification degree is 95% or more because the water resistance of the printed image is further improved, and the saponification degree is more preferably 98% or more, Most preferably, the degree of saponification is 99% or more.

  As the polymerization degree of polyvinyl alcohol, any degree of polymerization can be used, but a higher degree of polymerization is preferable because the absorbability of the pigment ink, the color density of the printed image, and the water resistance become better. Specifically, the polymerization degree is preferably 1500 or more, and more preferably 3500 or more.

  Moreover, the modified polyvinyl alcohol which introduce | transduced various modified groups can also be used as polyvinyl alcohol. Examples of the modifying group include acetoacetyl group, silyl group, quaternary ammonium base, carboxylic acid group, carboxylic acid group, sulfonic acid group, sulfonic acid group, ketone group, mercapto group, amino group, ethylene group and the like. It is done.

These can be obtained by polymerizing a vinyl acetate polymer, which is a precursor of polyvinyl alcohol, by saponifying a vinyl acetate copolymer obtained by copolymerizing a copolymerizable monomer or by reacting a modifying group with polyvinyl alcohol. it can.
Among these, acetoacetyl group- or silyl group-modified polyvinyl alcohol is preferable because the absorbability of the pigment ink and the water resistance of the printed image become better.

  The water-soluble resin (C) constituting the ink jet receiving agent of the present invention is more preferably a mixture of polyvinyl alcohol and polyvinyl pyrrolidone. In some ink-jet recording media, a phenomenon called “post-cure”, in which printability with respect to dye ink, in particular, decreases with time, has become a problem. This is a phenomenon that occurs because the absorbability of the dye ink is lowered due to the influence of heat and humidity, and it is presumed that the cause is that the ink-jet receiving layer is crystallized by hydrogen bonding or the like. When polyvinyl pyrrolidone is used in combination with polyvinyl alcohol, this post-cure is alleviated, so that the inkjet acceptor of the present invention can be applied not only to pigment inks but also to inkjet ink acceptors for dye inks.

Polyvinylpyrrolidone is a water-soluble resin generally obtained by polymerizing N-vinylpyrrolidone. Those having various molecular weights are available as commercial products such as “Luvitec K series” manufactured by BASF and “PVP K series” manufactured by ISP Investment Inc. (ISP, USA).
The weight average molecular weight of polyvinyl pyrrolidone is preferably 100,000 to 2,000,000 from the viewpoint of ink absorbability and ease of handling due to moderate viscosity.

  In addition, various modified polyvinylpyrrolidones obtained by copolymerizing various monomers copolymerizable with N-vinylpyrrolidone can also be used. Various modified polyvinylpyrrolidones can be produced and used. Examples of commercially available products include “Luvitec VA64” manufactured by BASF, which is a copolymer with vinyl acetate, “Luvitec VPI55K72W” manufactured by BASF, which is a copolymer with vinylimidazole, and vinyl caprolactam. “Luvitec VPC55K65W” manufactured by BASF Co., which is a copolymer, and “VIVIPRINT 121” manufactured by ISP, which is obtained by neutralizing a tertiary amino group site of a copolymer with N, N-dimethylaminopropylmethacrylamide with an acid. ”,“ VIVIPRINT131 ”,“ GAFQUAT755N ”manufactured by ISP, which is a tertiary amino group of a copolymer with N, N-dimethylaminoethyl methacrylate, quaternized with diethyl sulfate, and the like. it can.

Among these modified polyvinyl pyrrolidones, those containing a tertiary amine salt (for example, “VIVIPRINT 121” or “VIVIPRINT 131”) are preferably used. By using the modified polyvinyl pyrrolidone containing the above-mentioned tertiary amine salt, an ink jet receiving agent capable of forming an ink jet receiving layer excellent in ink absorbability and water resistance of a printed image can be obtained.
In addition, as long as the effect of this invention is not impaired, polyvinylpyrrolidone may be partially intramolecularly crosslinked.

  As the water-soluble resin (C), it is more preferable to use a mixture of polyvinyl alcohol having a saponification degree of 95% or more and a modified polyvinyl pyrrolidone containing a tertiary amine salt. By using the above-mentioned mixture as the water-soluble resin (C), an ink jet receiving agent capable of forming an ink jet receiving layer excellent in pigment ink absorbability, dye ink absorbability, and water resistance of printed images is obtained. be able to.

  As the water-soluble resin (C), it is particularly preferable to use a mixture of polyvinyl alcohol having a saponification degree of 99% or more and a modified polyvinyl pyrrolidone containing a tertiary amine salt. By using the mixture as described above as the water-soluble resin (C), it is excellent in absorbability of pigment ink, absorbability of dye ink, water resistance of the printed image, and can improve the color density of the printed image. An ink jet receiving agent capable of forming an ink jet receiving layer can be obtained.

Next, the water-soluble polyvalent metal salt (D) will be described.
The water-soluble polyvalent metal salt here is a polyvalent metal salt having solubility in water. For example, when a saturated aqueous solution of the polyvalent metal salt is prepared using water at 20 ° C., it is contained in 100 g of the saturated aqueous solution. The polyvalent metal salt is 1 g or more. Examples of the water-soluble polyvalent metal salt (D) include divalent metal salts such as magnesium salt, calcium salt, barium salt, iron (II) salt, copper (II) salt, zinc salt, aluminum salt, chromium A trivalent metal salt such as a salt can be used.

  By using the water-soluble polyvalent metal salt (D) in the inkjet receiver of the present invention, the following effects can be obtained. First of all, there is an effect of improving the absorbability of the pigment ink. In particular, it is effective in improving the absorptivity in an image portion with a large amount of ink.

  Second, there is an effect of improving the water resistance of the printed image. Water-soluble polyvalent metal salts contain metal ions, which are polyvalent cations, and bind to anionic groups in dyes and pigment molecules, which are coloring materials in inks, and dissolve the coloring materials in water. It is considered that the water resistance of the printed image is improved because the properties and dispersibility can be reduced.

  Third, it has the effect of preventing bleeding during printing. As described above, the metal ions in the water-soluble polyvalent metal salt are combined with the coloring material in the ink, and the ink droplets sprayed onto the ink jet recording medium are restrained from moving in the horizontal direction, thus having an effect of preventing bleeding. It is considered a thing.

  Fourth, there is an effect of relaxing the above-mentioned post cure. In general, various salts are considered to have an effect of suppressing hydrogen bonding, and it is considered that post-cure, which is a phenomenon derived from hydrogen bonding, can be mitigated.

  Of the water-soluble polyvalent metal salts (D), it is preferable to use a water-soluble magnesium salt from the viewpoint of high pigment ink absorbency improving effect and post-cure relaxation effect, for example, magnesium chloride, magnesium acetate, magnesium nitrate. , Magnesium sulfate, magnesium chlorate and the like can be used. Only one type of these may be used, or two or more types may be used.

  Of the water-soluble magnesium salts, magnesium chloride is particularly preferred because of its good solubility in water, its low cost and easy availability, and its high four effects.

  The blending ratios of the cationic polyurethane resin (B), the water-soluble resin (C), and the water-soluble polyvalent metal salt (D), which are essential components of the ink jet receiving agent of the present invention, are (B) and (C). It is preferable that (B) is in the range of 5 to 69 mass%, (C) is in the range of 30 to 94 mass%, and (D) is in the range of 1 to 30 mass% with respect to the total amount of and (D). An ink-jet receiving layer comprising the ink-jet receiving agent of the present invention having a blending ratio in the above range has good ink absorptivity and water resistance of printed images. Further, if the blending ratio is in the range of 10 to 49% by mass of (B), 50 to 89% by mass of (C), and 1 to 10% by mass of (D), the above-described ink absorptivity and printed image. The balance of water resistance is further improved.

  In the inkjet receiver of the present invention, the ratio between the aqueous medium and the solid content [that is, the cationic polyurethane resin (B), the water-soluble resin (C) and the water-soluble polyvalent metal salt (D)] is not particularly limited, It is necessary to determine in consideration of the viscosity and storage stability of the ink jet receiving agent. In general, when a water-soluble resin is dissolved in an aqueous medium, its viscosity increases exponentially with respect to the concentration of the water-soluble resin. Moreover, storage stability tends to deteriorate as the concentration increases. Therefore, although depending on the type of the water-soluble resin to be used, it is preferable to adjust the ratio of the aqueous medium to the solid content so that the viscosity of the ink jet receiving agent is 100,000 mPa · s or less. Moreover, it is also necessary to adjust the viscosity so as to be suitable for a coating apparatus or an impregnation processing apparatus used when coating or impregnating the ink-jet receiving agent of the present invention on various substrates.

Moreover, the ink jet receiving agent of the present invention may further contain an additive as long as the effects of the present invention are not impaired.
Examples of the additive include nonionic, cationic, anionic and amphoteric surfactants, pigment dispersants, silicone, fluorine and acetylenic diol leveling agents, colloidal silica, and colloidal. Examples thereof include anti-blocking agents such as alumina, inorganic pigments and resin beads, ultraviolet absorbers, antioxidants and antistatic agents.
The amount of these additives used is not particularly limited as long as the effects of the present invention are not impaired, but is preferably in the range of 0.01 to 5% by mass with respect to the total amount of solids in the ink jet receiving agent. .

  Further, the ink jet receiving agent of the present invention may contain various porous pigments such as silica, clay, alumina, calcium carbonate and the like. As the porous pigment, silica or alumina that has good ink absorbability, is easily available industrially, and has good compatibility with the cationic polyurethane resin (B) constituting the present invention may be used. Particularly preferred.

  The porous pigment is preferably used in the range of 10 to 90% by mass with respect to the total amount of solid content in the ink jet receiving agent.

  In addition, the inkjet receiver of the present invention is a known resin that can be dispersed in an aqueous medium within a range not impairing the effects of the present invention, such as vinyl acetate, ethylene vinyl acetate, acrylic, epoxy, and polyester. Further, it may contain a synthetic rubber such as polyamide, urethane, styrene / butadiene, acrylonitrile / butadiene, and acrylic / butadiene.

  Moreover, the ink jet receiving agent of the present invention may contain a known water-soluble cationic resin within a range not impairing the effects of the present invention. Examples of the water-soluble cationic resin include epichlorohydrin polyamide resin, amine epichlorohydrin resin, polyethyleneimine salt-containing resin, polyvinylamine salt-containing resin, polyvinylamidine resin, polyallylamine salt-containing resin, polyaminesulfone salt-containing resin, and polydiallyldimethylammonium chloride. Dicyandiamide-formalin polycondensate, cation-modified polyvinyl alcohol, cation group-containing water-soluble acrylic resin, cation-modified starch, neutralized salt of chitosan, and the like can be used.

  The inkjet receiver of the present invention is produced, for example, by mixing the cationic polyurethane resin aqueous dispersion, the water-soluble resin (C), the water-soluble polyvalent metal salt (D), and other components as necessary. Can do. As such a production method, for example, the water-soluble resin (C) and the water-soluble polyvalent metal salt (D) previously dispersed or dissolved in an appropriate aqueous medium, and the cationic polyurethane resin (B) A method of mixing the aqueous dispersion with various stirrers and dispersers is simple. The aqueous dispersion of the cationic polyurethane resin (B), the water-soluble resin (C), the water-soluble polyvalent metal salt (D), and other components are added to the aqueous medium in any order and mixed. It is also possible to manufacture by a method.

  Examples of the stirrer that can be used when mixing the aqueous dispersion of the cationic polyurethane resin (B), the water-soluble resin (C), the water-soluble polyvalent metal salt (D), and other components include a turbine blade and a propeller. A stirrer having a wing, a fiddler wing, a paddle wing, an anchor wing, a max blend wing, a ribbon wing, a disper wing, and the like can be used. As the disperser, for example, various homogenizers, bead mills, sand mills, line mills, sonorators, colloid mills, and the like can be used.

  Next, the ink jet recording medium of the present invention will be described.

  The ink jet recording medium of the present invention is obtained by forming an ink jet receiving layer on a substrate by volatilizing an aqueous medium contained in the ink jet receiving agent after coating or impregnating the ink jet receiving agent on various substrates. In addition, an ink jet recording medium having excellent pigment ink absorbability and water resistance of printed images can be produced.

  Examples of the substrate that can be used include paper, paperboard, resin-coated paper, various films, synthetic paper, fiber, nonwoven fabric, and spunbond.

  As a method for coating or impregnating the ink jet receiving agent on the various substrates, a known and usual method can be used, and is not particularly limited. For example, an air knife coater, a blade coater, a roll coater, a gravure coater, a comma A method using a coating machine such as a coater or a gate roll coater is simple.

  The ink jet receiving agent of the present invention hardly causes cracks when coated or impregnated on a substrate. Therefore, when coating or impregnating the inkjet receiving agent on the base material, there is no need for a process for preventing cracking of the film, for example, a drying process under low temperature conditions or a process of repeating coating several times. It is.

  The method of volatilizing the aqueous medium after coating the ink jet receiving agent of the present invention on the substrate is not particularly limited, but for example, a method of drying using a dryer is common. The drying temperature may be set to a temperature that can volatilize the aqueous medium and does not adversely affect the substrate.

  The ink jet recording medium of the present invention obtained by the above manufacturing method is capable of accepting ink jets having a thickness in the range of 3 to 30 μm in order to maintain characteristics such as ink absorbability at a practical level and maintain good production efficiency. Those having a layer are preferred.

  The ink jet recording medium obtained by the present invention is particularly useful as an ink jet recording medium for wide format printers because it is excellent in ink absorbability of pigment ink and water resistance of printed images.

  Hereinafter, the present invention will be described more specifically with reference to examples.

[Synthesis Example 1] Synthesis of Tertiary Amino Group-Containing Polyol (E) -I Into a four-necked flask equipped with a thermometer, a stirring device, a reflux condenser, and a dropping device, polypropylene glycol-diglycidyl ether (epoxy equivalent 201 g / Equivalent.) After charging 590 parts by mass, the flask was purged with nitrogen. Next, after heating using an oil bath until the temperature in the flask reaches 70 ° C., 380 parts by mass of di-n-butylamine is added dropwise over 30 minutes using a dropping device. The reaction was allowed for 10 hours. After completion of the reaction, using an infrared spectrophotometer (FT / IR-460Plus, manufactured by JASCO Corporation), it is confirmed that the absorption peak near 842 cm ⁻¹ due to the epoxy group of the reaction product has disappeared. A tertiary amino group-containing polyol (E) -I (amine equivalent 339 g / equivalent, hydroxyl equivalent 339 g / equivalent) was prepared.

[Synthesis Example 2] Preparation of cationic polyurethane resin aqueous dispersion (I) In a four-necked flask equipped with a thermometer, a stirring device, a reflux condenser, and a dropping device, "Nipporan 980R" [manufactured by Nippon Polyurethane Industry Polycarbonate polyol obtained by reacting 1,6-hexanediol and dimethyl carbonate, hydroxyl equivalent 986 g / equivalent. 863 parts by mass were dissolved in 260 parts by mass of methyl ethyl ketone.

  Subsequently, 176 parts by mass of 4,4′-dicyclohexylmethane diisocyanate and 0.2 part by mass of stannous octylate were added and reacted at 75 ° C. for 2 hours, and then the tertiary amino group-containing polyol obtained in Synthesis Example 1 was obtained. 161 parts by mass of (E) -I and 540 parts by mass of methyl ethyl ketone were added and reacted for 15 hours, then cooled to 60 ° C., and further 1.3 parts by mass of methanol was added and reacted for 1 hour.

  Next, 58 parts by mass of dimethylsulfuric acid was added and maintained at 60 ° C. for 3 hours, and then 400 parts by mass of methyl ethyl ketone, 600 parts by mass of isopropanol, and 2942 parts by mass of ion-exchanged water were added, and the mixture was sufficiently stirred. A dispersion was prepared. The aqueous dispersion obtained was distilled under reduced pressure to prepare a cationic polyurethane resin aqueous dispersion (I) having a nonvolatile content of 40% by mass and a pH of 6.6.

[Synthesis Example 3]
"Nipporan 980R" [manufactured by Nippon Polyurethane Industry Co., Ltd., polycarbonate obtained by reacting 1,6-hexanediol and dimethyl carbonate to a four-necked flask equipped with a thermometer, a stirring device, a reflux condenser, and a dropping device Polyol, hydroxyl equivalent 986 g / equivalent. 705 parts by mass, 352 parts by mass of a polyester (hydroxyl equivalent 951 g /.) Obtained by reacting neopentyl glycol, 1,4-butanediol, terephthalic acid and adipic acid, and at a reduced pressure of 0.095 MPa Dehydration was performed at 120 to 130 ° C.

  Next, after cooling to 70 ° C., 666 parts by mass of ethyl acetate was added, and the mixture was cooled to 50 ° C. and sufficiently stirred and mixed. Then, 280 parts by mass of 4,4′-dicyclohexylmethane diisocyanate and 0. 1 stannous octylate were added. 3 parts by mass was added and reacted at 70 ° C. for 2 hours.

  After completion of the reaction, 30 parts by mass of N-methyl-diethanolamine was added and reacted for 4 hours to prepare a urethane prepolymer solution having a terminal isocyanate group. Next, 14 parts by mass of hydrazine hydrate was added to the urethane prepolymer solution adjusted to 55 ° C., and a chain extension reaction was performed for 1 hour.

  Next, 1954 parts by mass of ethyl acetate and 31 parts by mass of dimethylsulfuric acid were added and held at 55 ° C. for 1 hour, then cooled to 40 ° C. and an aqueous dispersion was prepared by adding 3300 parts by mass of ion-exchanged water. did. The aqueous dispersion obtained was distilled under reduced pressure to prepare a milky white cationic polyurethane resin aqueous dispersion (II) having a nonvolatile content of 35% by mass and a pH of 6.5.

[Example 1]
8% by mass aqueous solution of the above-mentioned cationic polyurethane resin aqueous dispersion (I), PVA145H (manufactured by Kuraray Co., Ltd., polyvinyl alcohol having a saponification degree of 99.5% and a polymerization degree of 4500), and hexahydrate of magnesium chloride A 53.5 mass% aqueous solution of [Aqueous dispersion (I): 8 mass% aqueous solution of PVA145H: 53.5 mass% aqueous solution of magnesium chloride hexahydrate] was 28.6: 66. 7: 4.7 An ink jet receiving agent having a nonvolatile content of 10.9% by mass was prepared by sufficiently mixing with a stirrer equipped with a propeller blade.

  Apply the obtained inkjet receiver to a transparent polyethylene terephthalate film (A-4100, manufactured by Toyobo Co., Ltd.) that has been subjected to easy adhesion treatment, using wire bar No. 60, and dry at 120 ° C. for 4 minutes. Thus, an inkjet recording medium having an inkjet receiving layer having a thickness of 12 μm was produced.

[Example 2]
The same method as in Example 1 except that instead of the 8% by mass aqueous solution of PVA145H, an 8% by mass aqueous solution of PVA145 (manufactured by Kuraray Co., Ltd., polyvinyl alcohol having a saponification degree of 98.5% and a polymerization degree of 4500) was used. Thus, an inkjet receiver having a nonvolatile content of 10.9% by mass was prepared.

  By applying the obtained ink jet receiving agent on a transparent polyethylene terephthalate film (A-4100, manufactured by Toyobo Co., Ltd.) that has been subjected to easy adhesion treatment in the same manner as in Example 10, and drying it. An inkjet recording medium having an inkjet receiving layer having a thickness of 12 μm was produced.

Example 3
The cationic polyurethane resin aqueous dispersion (I), an 8% by mass aqueous solution of PVA145H (manufactured by Kuraray Co., Ltd., polyvinyl alcohol having a saponification degree of 99.5% and a polymerization degree of 4500), and VIVIPRINT131 [IS Investments -11 mass% aqueous solution of tertiary amine salt-containing modified polyvinyl pyrrolidone manufactured by Incorporated Co., Ltd. and 53.5 mass% aqueous solution of magnesium chloride hexahydrate [8 mass of aqueous dispersion (I): PVA145H The propeller blades were attached so that the mass ratio of 2% aqueous solution: VIVIPRINT131: 53.5 mass% aqueous solution of magnesium chloride hexahydrate was 28.6: 33.4: 33.4: 4.6 By sufficiently mixing with a stirrer, an inkjet receiver having a non-volatile content of 12.0% by mass was prepared.

  By applying the obtained ink jet receiving agent on a transparent polyethylene terephthalate film (A-4100, manufactured by Toyobo Co., Ltd.), which has been subjected to easy adhesion treatment, in the same manner as in Example 1, and drying. An inkjet recording medium having an inkjet receiving layer having a thickness of 12 μm was produced.

[Comparative Example 1]
Except not using 53.5 mass% aqueous solution of magnesium chloride hexahydrate and changing the mass ratio of [aqueous dispersion (I): 8 mass% aqueous solution of PVA145H] to 70:30, An ink jet receiving agent was prepared in the same manner as in Example 10. In addition, an ink jet recording medium was produced in the same manner as in Example 1 using the obtained ink jet receiving agent.

[Comparative Example 2]
Instead of the cationic polyurethane resin aqueous dispersion (I), a 52% by mass aqueous solution of polydiallyldimethylammonium chloride (hereinafter abbreviated as DADMAC), which is a water-soluble cationic resin, is used, and [DADMAC Except that the mass ratio of 52 mass% aqueous solution: 8 mass% aqueous solution of PVA145H: 53.5 mass% aqueous solution of magnesium chloride hexahydrate] was changed to 9.5: 85.7: 4.8. An ink jet receiving agent was prepared in the same manner as in Example 1. In addition, an inkjet recording medium was produced in the same manner as in Example 10 using the obtained inkjet receiver.

[Comparative Example 3]
The cationic polyurethane resin aqueous dispersion (I) was not used, and the mass ratio of [8 mass% aqueous solution of PVA145H: 53.5 mass% aqueous solution of magnesium chloride hexahydrate] was changed to 95: 5. Except for this, an inkjet receiver was prepared in the same manner as in Example 1, and then an inkjet recording medium was prepared.

[Comparative Example 4]
The cationic polyurethane resin aqueous dispersion (II), an 8% by mass aqueous solution of PVA145H (manufactured by Kuraray Co., Ltd., polyvinyl alcohol having a saponification degree of 99.5% and a polymerization degree of 4500), and VIVIPRINT 131 [ISP Investments -11 mass% aqueous solution of tertiary amine salt-containing modified polyvinyl pyrrolidone manufactured by Incorporated Co., Ltd. and 53.5 mass% aqueous solution of hexahydrate magnesium chloride [8 mass of aqueous dispersion (II): PVA145H % Aqueous Solution: VIVIPRINT 131: Magnesium Chloride Hexahydrate 53.5 wt% Aqueous Solution] Stirrer equipped with propeller blades so that the mass ratio was 28.6: 33.4: 33.4: 4.6 Was sufficiently mixed to prepare an ink jet receiving agent having a nonvolatile content of 12.0% by mass.

  By applying the obtained ink jet receiving agent on a transparent polyethylene terephthalate film (A-4100, manufactured by Toyobo Co., Ltd.) subjected to easy adhesion treatment in the same manner as in Example 1, and drying, An inkjet recording medium having an inkjet receiving layer having a thickness of 12 μm was produced.

[Evaluation method of pigment ink printability]
A wide format ink jet printer (manufactured by Hewlett-Packard Company, DJ-3800CP) is used, and cyan (hereinafter abbreviated as C), magenta (hereinafter abbreviated as M), yellow (hereinafter abbreviated as M). A 100% solid image of each color of black (hereinafter abbreviated as Y) and black (hereinafter abbreviated as Bk) was printed with pigment ink. The color density of each 100% solid image of C, M, Y, and Bk printed on each ink jet recording medium was measured using a reflection color density meter (D186, manufactured by Gretag).

[Evaluation method of pigment ink absorbency]
A wide format inkjet printer (manufactured by Hewlett-Packard, DJ-3800CP) was used, and a solid image of Y100% was printed on the inkjet recording medium with pigment ink. Next, a 400% solid image was printed with pigment ink, which was obtained by superimposing 100% of each color of C, M, Y, and Bk on the Y100% solid image. The degree of ink absorption of the printed 400% solid image, the presence or absence of cracks, and the presence or absence of bleeding were visually observed and evaluated.
The degree of ink absorption is “good” when the color of the printed 400% solid image is almost uniform, and “bad” when the color of the 400% solid image is partially uneven. evaluated.
The presence or absence of cracks was evaluated as “None” when no cracks occurred in the printed 400% solid image, and “Yes” when cracks occurred.
The presence / absence of bleeding was evaluated as “Yes” when the outline of the 400% solid image was blurred, and as “None” when the outline of the 400% solid image was not blurred. .

[Method for evaluating water resistance of printed images]
Each inkjet recording medium on which a solid image was printed, which was used in [Pigment ink printability evaluation method], was immersed in water at 25 ° C. for 1 hour, and then dried at room temperature and normal humidity for 1 day. The color density of each 100% solid image of C, M, Y, and Bk of the inkjet recording medium after drying is measured using a reflection color density densitometer (D186, manufactured by Gretag), and the color density before and after immersion is measured. The color density retention rate was calculated according to the following formula (3). An ink jet recording medium having a color density retention of 90% or more as a guide can be said to have a practically sufficient level of water resistance.
In addition, when each inkjet recording medium was immersed in water, when the inkjet receiving layer was dissolved in water, it was set as “impossible to measure”.

Formula (3)
Color density retention (%) = [(color density after immersion) / (color density before immersion)] × 100

[Dye ink printability evaluation method]
A 100% solid image of each color of C, M, Y, and Bk was printed with a dye ink on the inkjet recording medium using a wide format inkjet printer (DJ-3800CP, manufactured by Hewlett-Packard Company). The color density of each 100% solid image of C, M, Y, and Bk printed on each inkjet recording medium was measured using a reflection color density densitometer (D186, manufactured by Gretag).

[Evaluation method of dye ink absorbency]
A wide format inkjet printer (manufactured by Hewlett-Packard, DJ-3800CP) was used, and a solid image of Y100% was printed on the inkjet recording medium with dye ink. Next, a 400% solid image was printed with a dye ink in which 100% of each color of C, M, Y, and Bk was added to the 100% solid Y image. The degree of ink absorption of the printed 400% solid image, the presence or absence of cracks, and the presence or absence of bleeding were visually observed and evaluated.
The degree of ink absorption is “good” when the color of the printed 400% solid image is almost uniform, and “bad” when the color of the 400% solid image is partially uneven. evaluated.
The presence or absence of cracks was evaluated as “None” when no cracks occurred in the printed 400% solid image, and “Yes” when cracks occurred.
The presence / absence of bleeding was evaluated as “Yes” when the outline of the 400% solid image was blurred, and as “None” when the outline of the 400% solid image was not blurred. .

[Post-cure evaluation method]
Each inkjet recording medium was heat-treated at 160 ° C. for 5 minutes. Next, using an inkjet printer (manufactured by Hewlett-Packard, DJ-990CXI), 100% solid images of C, M, Y, and Bk were respectively printed on the heat-treated inkjet recording medium and the unheat-treated inkjet recording medium. Printed with dye ink.
Evaluation of post-cure is that there is no substantial difference between the hue of a 100% solid image printed on a heat-treated inkjet recording medium and the hue of a 100% solid image printed on an unheat-treated inkjet recording medium. “No” means that the hue of a 100% solid image printed on a heat-treated inkjet recording medium is unclear compared to the hue of a solid image printed on an unheat-treated inkjet recording medium. evaluated.
This evaluation method is an accelerated test assuming printing on an inkjet recording medium stored for a long period of time, and a post-cure evaluation of “none” means that the inkjet recording medium is good. To do.

  In Table 1, “PVA145H” indicates polyvinyl alcohol having a saponification degree of 99.5% and a polymerization degree of 4500 manufactured by Kuraray Co., Ltd. “PVA145” indicates a polyvinyl alcohol manufactured by Kuraray Co., Ltd. having a saponification degree of 98.5% and a polymerization degree of 4500. “VIVIPRINT 131” refers to an 11% by mass aqueous solution of tertiary amine salt-containing modified polyvinylpyrrolidone manufactured by IPS Investments, Inc.

In Table 2, “PVA145H” indicates polyvinyl alcohol having a saponification degree of 99.5% and a polymerization degree of 4500 manufactured by Kuraray Co., Ltd. “VIVIPRINT 131” refers to an 11% by mass aqueous solution of tertiary amine salt-containing modified polyvinylpyrrolidone manufactured by IPS Investments, Inc. “DADMAC” refers to polydiallyldimethylammonium chloride.

Claims (14)

An aqueous medium, a cationic polyurethane resin (B) containing a structural unit (A) represented by the following general formula [I] in the molecule dispersed in the aqueous medium, a water-soluble resin (C), Containing a polyvalent metal salt (D),
An inkjet receiving agent, wherein the content of the cationic amino group contained in the structural unit (A) in the cationic polyurethane resin (B) is 0.005 to 1.5 equivalent / kg.

[Wherein, R ₁ represents an alkylene group that may contain an aliphatic cyclic structure, a residue of a dihydric phenol, or a polyoxyalkylene group, and R ₂ and R ₃ independently represent an aliphatic group. An alkyl group which may contain a cyclic structure, R ₄ represents a hydrogen atom or a residue of a quaternizing agent introduced by a quaternization reaction, and X ⁻ represents an anionic counter ion. ] The inkjet receiving agent according to claim 1, wherein the cationic polyurethane resin (B) has a structural unit derived from a polyol obtained by esterification of carbonic acid and an aliphatic polyhydric alcohol. The inkjet acceptor according to claim 1, wherein the cationic polyurethane resin (B) has a structural unit derived from an alicyclic polyisocyanate and / or an aliphatic polyisocyanate. The inkjet receiving agent according to claim 1, wherein the water-soluble resin (C) is at least one resin selected from the group consisting of polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetal, polyalkylene oxide, and cellulose derivatives. The inkjet receiver according to claim 1, wherein the water-soluble resin (C) is polyvinyl alcohol. The ink jet receiving agent according to claim 5, wherein the degree of saponification of the polyvinyl alcohol is 95% or more. The ink jet receiving agent according to claim 5, wherein the degree of saponification of the polyvinyl alcohol is 98% or more. The ink-jet receiving agent according to claim 1, wherein the water-soluble resin (C) is a mixture of polyvinyl alcohol and polyvinyl pyrrolidone. The inkjet receiver according to claim 1, wherein the water-soluble resin (C) is a mixture of polyvinyl alcohol and a modified polyvinyl pyrrolidone containing a tertiary amine salt. The ink jet receiving agent according to claim 9, wherein the degree of saponification of the polyvinyl alcohol is 95% or more. The inkjet acceptor according to claim 9, wherein the saponification degree of the polyvinyl alcohol is 98% or more. The ink-jet receiving agent according to claim 1, wherein the water-soluble polyvalent metal salt (D) is a water-soluble magnesium salt. The ink-jet receiving agent according to any one of claims 1 to 11, wherein the water-soluble polyvalent metal salt (D) is magnesium chloride. An ink jet receiving layer formed on the base material by volatilizing the aqueous medium after coating or impregnating the base material with the ink jet receiving agent according to claim 1. recoding media.