JP5176670B2 - Non-aqueous inkjet ink and inkjet recording method - Google Patents

Description

  The present invention relates to a novel non-aqueous inkjet ink and inkjet recording method.

  In recent years, an inkjet recording method can be easily and inexpensively produced an image, and thus has been applied to various printing fields such as photographs, various printing, marking, and special printing such as a color filter.

  As the ink-jet ink used in such an ink-jet recording method, water-based ink mainly containing water, non-volatile solvent which does not volatilize at room temperature, oil-based ink which does not substantially contain water, solvent which volatilizes at room temperature A non-aqueous ink that is substantially free of water, a hot melt ink that heats and melts solid ink at room temperature, an actinic ray curable ink that cures with actinic rays such as light after printing, and the like. There are inkjet inks, and they are properly used depending on the application.

  On the other hand, plastic recording media such as polyvinyl chloride and polyethylene are used as recording media for outdoor postings that require long-term weather resistance and printed materials that require adhesion to curved objects. Recording media made of soft polyvinyl chloride are used in a wide range of applications. There are many methods for printing on soft polyvinyl chloride, but there is an inkjet recording method as a method suitable for the production of a small variety of products because there is no need to prepare a plate and the time to finish is short.

  When ink jet recording is performed on soft polyvinyl chloride, as an ink jet ink to be used, a non-aqueous ink containing a large amount of cyclohexanone or the like has been conventionally used. For example, an ink jet ink containing cyclohexanone is disclosed ( Patent Document 1). This cyclohexanone has a high solubility in soft polyvinyl chloride, and since the pigment in the ink-jet ink enters into the soft polyvinyl chloride, good scratch resistance and glossiness can be obtained. However, cyclohexanone has been designated as a first type organic solvent, which is not only a problem in safety, but also has a drawback that a local exhaust device is required when handling inkjet ink containing cyclohexanone.

On the other hand, non-aqueous inks characterized by not containing cyclohexanone have been developed and sold. For example, as a solvent for dissolving polyvinyl chloride, a non-aqueous ink containing a solvent such as N-methylpyrrolidone or amide is disclosed in place of cyclohexanone having the above-described problems (Patent Document 2,). 3). Further, for the purpose of improving image fastness such as scratch resistance, a non-aqueous ink to which a fixing resin such as vinyl chloride-vinyl acetate copolymer or acrylic is added is disclosed (see Patent Documents 4 and 5). With these configurations, it has been possible to obtain an ink jet ink that can suppress odor to some extent and can form an image having a certain degree of scratch resistance against polyvinyl chloride. However, ink-jet printers have recently been required to increase the printing speed as the demand for printed materials such as outdoor advertisements increases. It was a problem that occurred. For example, if the printed material immediately after inkjet printing is stored in a plurality of sheet forms, or if the printed material is stored in a roll shape, the printed material is insufficiently dried. May be soiled with undried ink, or a printed surface that is not sufficiently fixed may be damaged. In order to improve the drying property of the printed material, it is possible to use means such as heating the printed material during printing and / or after printing, or blowing warm air on the printing surface. The image quality of the printed matter may be adversely affected and may not be a preferable improvement means. Accordingly, there is a strong demand for inkjet inks that have both safety and odor problems and sufficient scratch resistance, and that are excellent in quick-drying properties that can contribute to an increase in the printing speed of inkjet printing.
Japanese translation of PCT publication No. 2002-526631 JP 2005-15672 A Japanese Patent Laid-Open No. 2005-60716 JP 2005-36199 A WO2004 / 007626 specification

  The present invention has been made in view of the above problems, and has an object of having printability (abrasion resistance, alcohol wiping resistance) on a plastic recording medium such as polyvinyl chloride, excellent safety, and odor. It is an object of the present invention to provide a non-aqueous ink-jet ink that can be used without any problems, and has excellent quick-drying properties for increasing the printing speed of a printer, and an ink-jet recording method using the same.

  The above object of the present invention can be achieved by the following configuration.

〔式中、Ｒ^１、Ｒ^２はそれぞれ独立に、炭素数が１〜６の、それぞれ置換されてもよい、アルキル基、シクロヘキシル基、又は、フェニル基を表し、Ｒ^１とＲ^２が結合して環を形成していてもよい。〕

〔式中、Ｒ^３、Ｒ^４はそれぞれ独立に、炭素数が１〜６の、それぞれ置換されてもよい、アルキル基、シクロヘキシル基、又は、フェニル基を表し、Ｒ^３とＲ^４が結合して環を形成していてもよい。〕
一般式（３）
Ｒ^５−ＯＯＣ（ＣＨ_２）ｎＣＯＯ−Ｒ^６
〔式中、Ｒ^５、Ｒ^６はそれぞれ独立に、炭素数が１〜５の直鎖又は分岐のアルキル基であり、分子中の２つのアルキル基は同一でも異なっていても良い。又、（３）式において、ｎは０から８の整数である。〕
前記定着樹脂が、数平均分子量が１００００〜３００００の範囲である塩化ビニル−酢酸ビニル共重合物、塩化ビニル−酢酸ビニル−無水マレイン酸共重合物、塩化ビニル−酢酸ビニル−ビニルアルコール共重合物及び塩化ビニル−酢酸ビニル−ヒドロキシアルキルアクリレート共重合物からなる群から選ばれる少なくとも１種である非水系インクジェットインク。 1. The pigment, the fixing resin, and at least one compound (A) selected from the group of compounds represented by the following general formulas (1) and (2) are 1.5% by mass or more and 30% by mass based on the total mass of the ink. % and less, and contains at least one compound selected from the group consisting of compounds represented by the following general formula (3) (B),

[Wherein, R ¹ and R ² each independently represents an alkyl group, a cyclohexyl group, or a phenyl group having 1 to 6 carbon atoms, each of which may be substituted, and R ¹ and R ² are bonded to each other. May form a ring. ]

[Wherein R ³ and R ⁴ each independently represent an alkyl group, a cyclohexyl group, or a phenyl group, each having 1 to 6 carbon atoms, which may be substituted, and R ³ and R ⁴ are bonded to each other. May form a ring. ]
General formula (3)
_{^{R 5 -OOC (CH 2) nCOO}} -R 6
[Wherein, R ⁵ and R ⁶ are each independently a linear or branched alkyl group having 1 to 5 carbon atoms, and two alkyl groups in the molecule may be the same or different. In the formula (3), n is an integer from 0 to 8. ]
The fixing resin is a vinyl chloride-vinyl acetate copolymer, a vinyl chloride-vinyl acetate-maleic anhydride copolymer, a vinyl chloride-vinyl acetate-vinyl alcohol copolymer having a number average molecular weight in the range of 10,000 to 30,000, and At least Tanedea Ru non-aqueous inkjet ink selected from the group consisting of hydroxy alkyl acrylate copolymer - vinyl chloride - vinyl acetate.

2. 2. The non-aqueous inkjet ink according to 1 above, further comprising a solvent (C) composed of one or more compounds selected from the group of compounds represented by the following general formulas (4) and (5).

[In the formula, R ⁷ , R ⁸ Represents a methyl group or an ethyl group, respectively, and OX ¹ Represents an oxyethylene group or an oxypropylene group. ]

[In the formula, R ⁹ , R ¹⁰ Represents a methyl group or an ethyl group, respectively, and OX ² Represents an oxyethylene group or an oxypropylene group. ]

3. The non-aqueous inkjet ink according to 2 above, wherein the total content of the solvent (C) and the content of the compound (B) is 50% by mass or more and 85% by mass or less.

4). The non-aqueous inkjet ink according to 2 or 3 above, wherein the solvent (C) is at least one selected from diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, ethylene glycol diacetate and propylene glycol diacetate. .

5. The non-aqueous inkjet ink according to any one of 1 to 4, wherein the fixing resin is a resin synthesized by a solution polymerization method.

6). The non-aqueous inkjet ink according to any one of 1 to 5, wherein the compound represented by the formula (3) is selected from the group consisting of dimethyl succinate, dimethyl glutarate, and dimethyl adipate.

7). An inkjet recording method for recording an image on a recording medium using the non-aqueous inkjet ink according to any one of 1 to 6, wherein the recording medium does not contain polyvinyl chloride or a plasticizer. An ink jet recording method which is at least one selected from recording media comprising a material and a non-absorbing inorganic base material as a constituent element.

  According to the present invention, it has printability (scratch resistance, alcohol wiping resistance) on a plastic recording medium such as polyvinyl chloride, is excellent in safety, can be used without problems of odor, and increases the printing speed of the printer. Therefore, it was possible to provide a non-aqueous ink jet ink excellent in quick drying and an ink jet recording method using the same.

  Hereinafter, the best mode for carrying out the present invention will be described in detail.

  In light of the above problems, the present inventors have conducted extensive studies on various solvents and combinations thereof for non-aqueous inkjet inks. As a result, the present inventors contain at least a pigment and a fixing resin, and the general formulas (1) and (2) At least one compound (A) selected from the compound group represented by the formula (3) is contained in an amount of 1.5% by mass or more and 30% by mass or less, and is selected from the compound group represented by the general formula (3). Non-water-based inkjet ink characterized by containing more than one kind of compound (B) has printability (scratch resistance, alcohol wiping resistance) on plastic recording media such as polyvinyl chloride, and is safe It has been found that a non-aqueous inkjet ink that is excellent, can be used without problems of odor, and is excellent in quick-drying can be realized.

  Hereinafter, the configuration of the non-aqueous inkjet ink of the present invention will be specifically described.

  The non-aqueous inkjet ink of the present invention (hereinafter also referred to as inkjet ink or ink) contains a pigment and a fixing resin, and is at least one selected from the group of compounds represented by the general formulas (1) and (2). It contains at least 1.5% by mass and not more than 30% by mass of the compound (A), and contains at least one compound (B) selected from the compound group represented by the general formula (3). And Although the detailed mechanism is unknown, the present inventors have found that when the compound (B) coexists with the compound (A), the permeability of the ink into the resin recording medium increases synergistically. By discovering it and applying it to non-aqueous ink-jet inks, we have completed an ink with dramatically improved quick-drying properties.

[Compounds represented by general formulas (1) and (2)]
Next, details of the compounds represented by the general formulas (1) and (2) according to the present invention will be described.

In the general formula (1), R ¹ and R ² each represent a substituent having 1 to 6 carbon atoms, for example, a linear or branched alkyl such as a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. Groups, alkyl groups substituted with heteroatoms such as hydroxyethyl group, acetyl group, and acetonyl group, cyclic groups such as cyclohexyl group and phenyl group, or aromatic substituents, and R ¹ and R ² are They may be the same or different, and R ¹ and R ² may be bonded to each other to form a ring.

In the general formula (2), R ³ and R ⁴ each represent a substituent having 1 to 6 carbon atoms, for example, a linear or branched alkyl such as a methyl group, an ethyl group, an n-propyl group, or an isopropyl group. Groups, alkyl groups substituted by heteroatoms such as hydroxyethyl group, acetyl group and acetonyl group, cyclic groups such as cyclohexyl group and phenyl group, or aromatic substituents, and further R ³ and R ⁴ are They may be the same or different, and R ³ and R ⁴ may be bonded to each other to form a ring.

  Examples of the compound represented by the general formulas (1) and (2) include dimethyl sulfoxide, diethyl sulfoxide, methyl ethyl sulfoxide, diphenyl sulfoxide, tetraethylene sulfoxide, dimethyl sulfone, methyl ethyl sulfone, and methyl-isopropyl sulfone. , Methyl-hydroxyethyl sulfone, sulfolane and the like.

  The content in the inkjet ink of at least one compound (A) selected from the compound group represented by the general formulas (1) and (2) is 1.5% by mass or more and 30% by mass or less. More preferably, it is 3 mass% or more and 20 mass% or less, Most preferably, it is 5 mass% or more and 15 mass% or less. When the content of the compound (A) is 1.5% or more, the solubility of the ink in polyvinyl chloride is sufficient, and scratch resistance and alcohol wiping resistance against polyvinyl chloride can be obtained. Moreover, if it is 3 mass% or more, the abrasion resistance with respect to polyvinyl chloride and alcohol wiping resistance are favorable, and if it is 30 mass% or less, stable emission without causing abnormalities of the inkjet head due to long-term use. It can be performed.

[Compound represented by formula (3)]
Subsequently, the detail of the compound represented by the said General formula (3) based on this invention is demonstrated.

In the general formula (3), R ⁵ and R ⁶ are each a linear or branched alkyl group having 1 to 5 carbon atoms, preferably a methyl group or an ethyl group. Two alkyl groups in the molecule may be the same or different. In General formula (3), n is an integer of 0-8, Preferably it is an integer of 0-4.

  Examples of the compound represented by the general formula (3) include dimethyl oxalate, diethyl oxalate, dipropyl oxalate, diisopropyl oxalate, dibutyl oxalate, diisobutyl oxalate, di-t-butyl oxalate, Diamyl oxalate, dimethyl malonate, diethyl malonate, dipropyl malonate, diisopropyl malonate, dibutyl malonate, diisobutyl malonate, di-t-butyl malonate, diamyl malonate, dimethyl succinate, diethyl succinate, succinic acid Dipropyl, Diisopropyl succinate, Dibutyl succinate, Diisobutyl succinate, Di-t-butyl succinate, Diamyl succinate, Dimethyl glutarate, Diethyl glutarate, Dipropyl glutarate, Diisopropyl glutarate, Dibutyl glutarate, Diisobutyrate Chill, di-t-butyl glutarate, diamyl glutarate, dimethyl adipate, diethyl adipate, dipropyl adipate, diisopropyl adipate, dibutyl adipate, diisobutyl adipate, di-t-butyl adipate, diamyl adipate, Dimethyl pimelate, Diethyl pimelate, Dipropyl pimelate, Diisopropyl pimelate, Dibutyl pimelate, Diisobutyl pimelate, Di-t-butyl pimelate, Diamyl pimelate, Dimethyl perphosphate, Diethyl perphosphate, Dipropyl sperate Diisopropyl, dibutyl spellate, diisobutyl spellate, di-t-butyl sperate, diamyl spellate, dimethyl azelate, diethyl azelate, dipropyl azelate, azelain Diisopropyl, dibutyl azelate, diisobutyl azelate, di-t-butyl azelate, diamyl azelate, dimethyl sebacate, diethyl sebacate, dipropyl sebacate, diisopropyl sebacate, dibutyl sebacate, diisobutyl sebacate, di-sebacate Examples thereof include t-butyl and diamyl sebacate.

  Among these, dimethyl succinate, dimethyl glutarate, and dimethyl adipate are preferred because they are superior in synergistic quick drying effect in combination with the compound (A).

  As the compound represented by the general formula (3), one type of compound may be used alone, or two or more types of compounds may be used in combination.

[Compounds represented by general formulas (4) and (5)]
The ink-jet ink of the present invention can contain a non-aqueous solvent, but includes a solvent (C) composed of one or more compounds selected from the compound group represented by the general formulas (4) and (5). It is preferable to contain.

In the general formula (4), R ⁷ and R ⁸ each represent a methyl group or an ethyl group, and OX ¹ represents an oxyethylene group or an oxypropylene group.

In the general formula (5), R ⁹ and R ¹⁰ each represent a methyl group or an ethyl group, and OX ² represents an oxyethylene group or an oxypropylene group.

  Specific compounds represented by the general formulas (4) and (5) according to the present invention include, for example, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, ethylene glycol diacetate, propylene Examples thereof include glycol diacetate.

  Among these, the component of the solvent (C) is preferably at least one selected from diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, ethylene glycol diacetate and propylene glycol diacetate. The quick-drying property of the ink when printed on vinyl can be further improved. Among them, a particularly preferable solvent (C) is one containing diethylene glycol diethyl ether and ethylene glycol diacetate in a ratio of at least 1: 1 to 10: 1.

  The total of the content of the solvent (C) and the content of the compound (B) in the ink-jet ink is preferably 50% by mass or more and 90% by mass or less. In addition to improving the quick drying property and emission stability at the time of vinyl chloride printing, the odor of the ink can be reduced.

[Other solvents]
The inkjet ink of the present invention may contain a conventionally known solvent in addition to the compound (A) and the compound (B) solvent (C) according to the present invention as long as the object effects of the present invention are not impaired. Examples of such solvents include alkylene glycol monoalkyl ethers such as diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and tripropylene glycol monomethyl ether, ethylene glycol dibutyl ether, and tetraethylene glycol dimethyl ether. And alkylene glycol dialkyl ethers such as ethylene glycol monobutyl ether acetate.

[Fixing resin]
Next, the fixing resin according to the present invention will be described.

  In the ink-jet ink of the present invention, various fixing resins (hereinafter also simply referred to as resins) are added in order to improve fixability when recording on a plastic recording medium such as polyvinyl chloride.

  Examples of the resin to be added include acrylic resins, polyester resins, polyurethane resins, vinyl chloride resins, vinyl chloride-vinyl acetate copolymer resins, and the like.

  Specifically, acrylic resins such as John Crill (manufactured by Johnson Polymer Co., Ltd.), ESREC P (manufactured by Sekisui Chemical Co., Ltd.), polyester resins such as Elitel (manufactured by Unitika Ltd.) and Byron (manufactured by Toyobo Co., Ltd.), Byron UR ( Toyobo Co., Ltd.), NT-Hilamic (Daiichi Seika Co., Ltd.), Crisbon (Dainippon Ink Chemical Co., Ltd.), Nipporan (Nippon Polyurethane Co., Ltd.) and other polyurethane resins, SOLBIN (Nisshin Chemical Co., Ltd.), Vinyl Blanc (Nissin Chemical Industry Co., Ltd.), Saran Latex (Asahi Kasei Chemicals Co., Ltd.), Sumielite (Sumitomo Chemical Co., Ltd.), Sekisui PVC (Sekisui Chemical Co., Ltd.), UCAR (Dow Chemical Co., Ltd.) Can be mentioned.

  The fixing resin acts as a binder that adheres a coloring material such as a pigment to the recording medium after printing. The larger the molecular weight of the fixing resin, the better the adhesion and durability. In addition, the smaller the molecular weight, the lower the viscosity of the ink. However, the lower the viscosity, the lower the energy required for ejecting the ink during printing, so that the inkjet head is not burdened and it is easier to eject stably. Therefore, if the number average molecular weight is 10,000 or more, the fixability after printing is sufficiently exhibited, and if it is 30000 or less, it does not impose a load on the ejection of the ink, which is preferable.

  Particularly preferred fixing resins have a number average molecular weight in the range of 10,000 to 30,000, and compositions include vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, vinyl chloride-vinyl acetate- At least one resin selected from vinyl alcohol copolymer and vinyl chloride-vinyl acetate-hydroxyalkyl acrylate copolymer, vinyl chloride-vinyl acetate copolymer and vinyl chloride-vinyl acetate-maleic anhydride copolymer These vinyl chloride-vinyl acetate copolymers and vinyl chloride-vinyl acetate-maleic anhydride copolymers may be mixed with acrylic resins, polyester resins, polyurethane resins, etc. May be used.

  By adding these fixing resins to the ink of the present invention, the emission stability, scratch resistance and alcohol wiping resistance can be improved in a balanced manner.

  The alcohol wiping resistance referred to in the present invention is resistance to disturbance such as image peeling when wiping the surface of the image with ethanol or a mixed solvent of ethanol and water. Wipe off dirt on the image surface with alcohol for posters for outdoor use. It is a user need for that.

  As a method for synthesizing the fixing resin according to the present invention, a suspension polymerization method, an emulsion polymerization method, a solution polymerization method, and the like can be applied without particular limitation. Among them, the solution polymerization method is preferable.

  The solution polymerization method is one of the methods used for radical polymerization of a monomer having a vinyl group. The monomer and initiator are dissolved in a solvent in which the polymer to be generated is soluble, and the polymerization is performed by heating. Is the method.

  The fixing resin synthesized by the solution polymerization method has high solubility even if it has a relatively high molecular weight, and more resin can be contained in the ink, so that the scratch resistance can be improved.

  The content of the fixing resin in the ink of the present invention is preferably 1 to 10% by mass. When the content is 1% by mass or more, the image weather resistance when recorded on polyvinyl chloride is enhanced, and when the content is 10% by mass or less, the ink ejection from the inkjet head is easily stabilized, and more preferable. The range of content is 3-7 mass%.

[Pigment]
Next, the pigment according to the present invention will be described.

  In the non-aqueous ink jet ink of the present invention, the weather resistance of the recorded matter recorded on a plastic recording medium such as polyvinyl chloride can be enhanced by using a pigment as a coloring material.

  As the pigment that can be used in the present invention, conventionally known pigments can be used without particular limitation. For example, organic pigments such as insoluble pigments and lake pigments, and inorganic pigments such as carbon black can be preferably used.

  The insoluble pigment is not particularly limited. Dioxazine, thiazole, phthalocyanine, diketopyrrolopyrrole and the like are preferable.

  Specific pigments that can be preferably used include the following pigments.

  Examples of the magenta or red pigment include C.I. I. Pigment red 2, C.I. I. Pigment red 3, C.I. I. Pigment red 5, C.I. I. Pigment red 6, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 15, C.I. I. Pigment red 16, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 48: 1, C.I. I. Pigment red 53: 1, C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 139, C.I. I. Pigment red 144, C.I. I. Pigment red 149, C.I. I. Pigment red 166, C.I. I. Pigment red 168, C.I. I. Pigment red 177, C.I. I. Pigment red 178, C.I. I. Pigment red 184, C.I. I. Pigment red 202, C.I. I. Pigment red 209, C.I. I. Pigment red 222, C.I. I. Pigment red 254, C.I. I. Pigment violet 19 and the like.

  Examples of the pigment for orange or yellow include C.I. I. Pigment orange 31, C.I. I. Pigment orange 43, C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 15, C.I. I. Pigment yellow 15: 3, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 109, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 130, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 147, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 185, C.I. I. Pigment yellow 213, C.I. I. And CI Pigment Yellow 214.

  Examples of the pigment for green or cyan include C.I. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. And CI Pigment Green 7.

In addition to the above, when red, green, blue and intermediate colors are required, the following pigments are preferably used alone or in combination. I. Pigment Red 209, 224, 177, 194;
C. I. Pigment Orange 43;
C. I. Vat Violet 3;
C. I. Pigment Violet 19, 23, 37;
C. I. Pigment Green 36, 7;
C. I. Pigment Blue 15: 6;
Etc. are used.

  Examples of black pigments include C.I. I. Pigment black 1, C.I. I. Pigment black 6, C.I. I. Pigment black 7 and the like.

  The content of these pigments in the ink of the present invention is preferably 2 to 10% by mass. In order to reduce the graininess of the image, a light color ink may be used. In this case, the pigment content is preferably 1/5 to 1/2 with respect to the dark color ink.

  The pigment according to the present invention is preferably used after being dispersed by a disperser together with an acid-treated pigment derivative according to the present invention, a dispersing agent and other additives necessary for various desired purposes. As the disperser, conventionally known dispersers such as a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, a pearl mill, a wet jet mill, and a paint shaker can be used.

  The average particle size of the pigment dispersion used in the ink of the present invention is preferably 10 nm or more and 200 nm or less, and more preferably 50 nm or more and 150 nm or less. By making the average particle size 10 nm or more, aggregation of pigment particles is less likely to occur, and by making the average particle size 200 nm or less, it becomes easy to suppress the phenomenon that the pigment settles when stored over a long period of time. By setting the average particle size in the above range, it becomes easy to obtain an ink having good storage stability.

  The particle size of the pigment dispersion can be measured by a commercially available particle size measuring device using a light scattering method, an electrophoresis method, a laser Doppler method or the like. It is also possible to obtain a particle image with a transmission electron microscope on at least 100 particles and perform statistical processing on the image using image analysis software such as Image-Pro (manufactured by Media Cybernetics). Is possible.

  As the pigment dispersant, a surfactant, a polymer dispersant and the like are used, and a polymer dispersant is preferable. Polymer dispersing agents include (meth) acrylic resins, styrene- (meth) acrylic resins, hydroxyl group-containing carboxylic acid esters, salts of long-chain polyaminoamides and high molecular weight acid esters, salts of high molecular weight polycarboxylic acids, long Salt of chain polyaminoamide and polar acid ester, high molecular weight unsaturated acid ester, modified polyurethane, modified polyacrylate, polyether ester type anionic activator, naphthalenesulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate salt, Examples thereof include condensates or salt formation products of polyallylamine and polyester having a free carboxylic acid, polyoxyethylene alkyl phosphate ester, polyoxyethylene nonylphenyl ether, stearylamine acetate, pigment derivatives and the like.

  Specifically, Jonkrill (manufactured by Johnson Polymer), Anti-Terra-U (manufactured by BYK Chemie), Disperbyk (manufactured by BYK Chemie), Efka (manufactured by Efka CHEMICALS), Floren (manufactured by Kyoeisha Chemical), Disparon (manufactured by Enomoto Kasei Co., Ltd.), Ajisper (manufactured by Ajinomoto Fine Techno Co., Ltd.), Demole (manufactured by Kao Corporation), Homogenol, Emulgen (manufactured by Kao Corporation), Solspers (manufactured by Avicia), Nikkor (manufactured by Nikko Chemical Co., Ltd.), etc. Is mentioned. Among these, Ajisper PB-821 and PB-822 (manufactured by Ajinomoto Fine Techno Co., Ltd.) are more preferable as an embodiment of the present invention.

  The content of the dispersant in the inkjet ink of the present invention is preferably 10 to 200% by mass with respect to the pigment. By setting the content to 10% by mass or more, the pigment dispersion stability is enhanced, and by setting the content to 200% by mass or less, the ink ejection from the inkjet head is easily stabilized.

  In the present invention, a pigment derivative having an acidic group may be used in combination with a pigment.

[Pigment derivative having acidic group]
The pigment derivative having an acidic group refers to a compound in which an acidic functional group is bonded directly or via a joint to a mother nucleus having a pigment structure. Examples of the acidic functional group include a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a boric acid group, and a hydroxyl group, preferably a sulfonic acid group and a carboxylic acid group, and more preferably a sulfonic acid group.

  Examples of methods for preparing pigment particles having an acidic functional group on the surface include WO97 / 48769, JP-A-10-110129, JP-A-11-246807, JP-A-11-57458, and JP11-189739. By treating the pigment particle surface described in JP-A-11-323232, JP-A-2000-265094, etc. with an appropriate oxidizing agent, at least a part of the pigment surface has a sulfonic acid group or a salt thereof. A method of introducing an acidic functional group is mentioned. Specifically, it is prepared by oxidizing carbon black with concentrated nitric acid, or in the case of color pigments by oxidizing with sulfamic acid, sulfonated pyridine salt, amide sulfuric acid, etc. in sulfolane or N-methyl-2-pyrrolidone. can do. A pigment dispersion can be obtained by removing and purifying a substance that has been excessively oxidized and becomes water-soluble by these reactions. Moreover, when a sulfonic acid group is introduced to the surface by oxidation, the acidic group may be neutralized with a basic compound as necessary.

  Other methods include a method of adsorbing the pigment derivatives described in JP-A-11-49974, JP-A-2000-273383, JP-A-2000-303014, etc. on the surface of the pigment particles by a treatment such as milling. Examples include a method of dissolving the pigment described in each publication such as 2002-179777, 2002-20141, and the like together with a pigment derivative, followed by crystallization in a poor solvent. Pigment particles having an acidic functional group on the surface can be obtained.

  In the present invention, the acidic functional group may be free or in a salt state, or may have a counter salt. Examples of the counter salt include inorganic salts (lithium, sodium, potassium, magnesium, calcium, aluminum, nickel, ammonium) and organic salts (triethylammonium, diethylammonium, pyridinium, triethanolammonium, etc.), preferably 1 A counter salt having a valence.

  Furthermore, as a pigment derivative having a more preferable acidic group, a compound represented by the following general formula (6) can also be used.

In the above general formula (6), P represents azo, benzimidazolone, phthalocyanine, quinacridone, anthraquinone, dioxazine, diketopyrrolopyrrole, quinophthalone, isoindolinone, isoindoline, perylene. , A kind of organic dye residue selected from perinone, flavanthrone, pyranthrone, or anthrapyrimidine, X is a sulfonic acid group or carboxylic acid group, R ₁ is an alkyl group having 5 to 20 carbon atoms, R ₂ , R ₃ and R ₄ each independently represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

  Further, the pigment derivative represented by the general formula (6) can be obtained by salting a pigment derivative having a sulfonic acid group or a carboxylic acid group introduced with an amine. Examples of amines include primary amines such as octylamine and dodecylamine, secondary amines such as dioleylamine and distearylamine, tertiary amines such as dimethyllaurylamine and dimethylstearylamine, trimethylammonium, dimethyldistearylammonium and the like. The primary amine and quaternary amine are preferred.

  The pigment derivative having an acidic group according to the present invention is preferably in the range of 0.2 to 15 mass%, more preferably in the range of 1 to 10 mass%, based on the total amount of the pigment and the pigment derivative. The pigment contained in the ink of the present invention and the pigment structure portion of the core of the pigment derivative do not necessarily have the same structure, but considering the hue of the ink finally prepared, For yellow pigments, red pigments for red pigments, blue pigments for blue pigments, etc., close to the hue of the dispersed pigment, or colorless Is preferred in that a pigment dispersion excellent in hue can be obtained.

[Other additives]
In addition to the above description, the inkjet ink of the present invention is publicly known depending on the purpose of improving the emission stability, print head and ink cartridge compatibility, storage stability, image storage stability, and other various performances as necessary. Various additives such as a viscosity modifier, a specific resistance modifier, a film forming agent, an ultraviolet absorber, an antioxidant, a discoloration inhibitor, an antifungal agent, and a rust inhibitor can be appropriately selected and used.

[Inkjet recording method]
The ink-jet head used when forming an image by discharging the ink-jet ink of the present invention may be an on-demand system or a continuous system. In addition, as a discharge method, an electro-mechanical conversion method (for example, a single cavity type, a double cavity type, a bender type, a piston type, a shear mode type, a shared wall type, etc.), an electro-thermal conversion method (for example, thermal ink jet) Any ejection method such as a mold, a bubble jet (registered trademark) mold, or the like may be used.

  In the ink jet recording method using the ink jet ink of the present invention, for example, an ink jet recorded image is obtained by ejecting ink from an ink jet head based on a digital signal and adhering it to a recording medium by a printer loaded with the ink jet ink. . In order to quickly and surely dry the ink adhered to the recording medium, a method of forming an image by increasing the surface temperature of the recording medium is preferable.

  The surface temperature is adjusted according to the durability of the recording medium and the drying property of the ink used, but is preferably 40 to 100 ° C. In particular, when polyvinyl chloride is used as the recording medium, increasing the surface temperature improves the wettability of the ink with respect to the surface of the recording medium. Therefore, it is more preferable to record at a higher surface temperature.

  Depending on the brand of the recording medium made of polyvinyl chloride, there may be a difference in wettability and ink drying, so the surface temperature may be adjusted according to the characteristics of each medium.

  When recording is performed by increasing the surface temperature of the recording medium, it is preferable to mount a heater on the ink jet recording apparatus, and by heating the recording medium before or during transport of the recording medium, the surface temperature of the recording medium alone by the ink jet recording apparatus Can be adjusted.

〔recoding media〕
In the inkjet recording method of the present invention, when an image is recorded on a recording medium using the non-aqueous inkjet ink of the present invention, polyvinyl chloride, a resin base material not containing a plasticizer, and a non-absorbing material are used as the recording medium. It is characterized by using at least one recording medium selected from recording media having an inorganic base material as a constituent element.

  Specific examples of polyvinyl chloride, which is one of the recording media used in the ink jet recording method of the present invention, include SOL-371G, SOL-373M, SOL-4701 (manufactured by Big Technos Co., Ltd.), glossy PVC (Co., Ltd.). Systemgraph Co., Ltd.), KSM-VS, KSM-VST, KSM-VT (above, manufactured by Kimoto Co., Ltd.), J-CAL-HGX, J-CAL-YHG, J-CAL-WWWG (above, Showa Co., Ltd.) (Made in Osaka), BUS MARK V400 F vinyl, litecal V-600F vinyl (above, made by Flexcon), FR2 (made by Hanwha) LLBAU13713 (above, made by Sakurai Co., Ltd.), P-370B, P-400M (above , Manufactured by Kambo Plus Co., Ltd.), S02P, S12P S13P, S14P, S22P, S24P, S34P, S27P (above, manufactured by Grafityp), P-223RW, P-224RW, P-249ZW, P-284ZC (above, manufactured by Lintec Corporation), LKG-19, LPA-70 , LPE-248, LPM-45, LTG-11, LTG-21 (above, manufactured by Shinsei Co., Ltd.), MPI 3023 (manufactured by Toyo Corporation), Napoleon Gloss gloss PVC (manufactured by Futaki Electronics Co., Ltd.), JV-610, Y-114 (above, manufactured by ICC Corporation), NIJ-CAPVC, NIJ-SPVCGT (above, manufactured by Nichie Corporation), 3101 / H12 / P4, 3104 / H12 / P4, 3104 / H12 / P4S 9800 / H12 / P4, 3100 / H12 / R2, 3 101 / H12 / R2, 3104 / H12 / R2, 1445 / H14 / P3, 1438 / One Way Vision (manufactured by Inetrcoat), JT5129PM, JT5728P, JT5822P, JT5829P, JT5829R, JT5829PM, JT5829PM, JM59t MPI1005, MPI1900, MPI2000, MPI2001, MPI2002, MPI3000, MPI3021, MPI3500, MPI3501 (above, manufactured by Avery), AM-101G, AM-501G (above, manufactured by Ginichi Co., Ltd.), FR2 (Hanfa Japan Co., Ltd.), AY-15P, AY-60P, AY-80P, DBSP137GGH, DBSP137GGL (above, Inc.) Insight Co., Ltd.), SJT-V200F, SJT-V400F-1 (above, manufactured by Hiraoka Orizome Co., Ltd.), SPS-98, SPSM-98, SPSH-98, SVGL-137, SVGS-137, MD3-200, MD3-301M, MD5-100, MD5-101M, MD5-105 (manufactured by Metamark), 640M, 641G, 641M, 3105M, 3105SG, 3162G, 3164G, 3164M, 3164XG, 3164XM, 3165G, 3165SG, 3165M, 3169M , 3451SG, 3551G, 3551M, 3631, 3641M, 3651G, 3651M, 3651SG, 3951G, 3641M (above, manufactured by Orafol), SVTL-HQ130 (manufactured by Lamy Corporation), SP 00 GWF, SPCLEARAD vinyl (above, manufactured by Catalina), RM-SJR (produced by Ryoyo Corporation), Hi Lucky, New Lucky PVC (above, made by LG), SIY-110, SIY-310, SIY-320 ( As described above, Sekisui Chemical Co., Ltd., PRINT MI Frontlit, PRINT XL Light weight banner (hereinafter, manufactured by Endutex), RIJET 100, RIJET 145, RIJET 165 (above, manufactured by Ritrama), NM-SG, NM-SM NEIEI KAKO Co., Ltd.), LTO3GS (Lukio Co., Ltd.), Easy Print 80, Performance Print 80 (above, Jetgraph Co., Ltd.), DSE 550, DSB 550, DSE 800 G, DSE 802/137, V250WG, V300WG, V350WG (above, manufactured by Hexis), Digital White 6005PE, 6010PE (above, made by Multifix), and the like.

  In addition, as a recording medium having a resin base material that does not contain a plasticizer or a non-absorbing inorganic base material as a constituent element, the following various base materials are used as constituent elements, and one kind of base material is used alone, or a plurality of kinds are used. These substrates can be used in combination. Examples of the resin base material containing no plasticizer used in the present invention include ABS resin, polycarbonate (PC) resin, polyacetal (POM) resin, polyamide (PA) resin, polyethylene terephthalate (PET) resin, and polyimide (PI). Examples thereof include a resin, an acrylic resin, a polyethylene (PE) resin, a polypropylene (PP) resin, and a hard polyvinyl chloride (PVC) resin that does not contain a plasticizer.

  These resins are characterized by not containing a plasticizer, but there are no particular restrictions on other properties such as thickness, shape, color, softening temperature, and hardness.

  The recording medium used in the present invention is preferably ABS resin, PET resin, PC resin, POM resin, PA resin, PI resin, hard PVC resin containing no plasticizer, acrylic resin, PE resin, or PP resin. More preferred are ABS resin, PET resin, PC resin, PA resin, hard PVC resin not containing plasticizer, and acrylic resin.

  Moreover, as a non-absorbing inorganic base material used for this invention, a metal plate, such as a glass plate, iron, and aluminum, a ceramic plate etc. are mentioned, for example. These inorganic substrates are characterized by not having an ink-absorbing layer on the surface. These non-absorbing inorganic base materials are not particularly limited with respect to other properties such as thickness, shape, color, softening temperature, and hardness.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

  Further, the pigment dispersant and fixing resin described below were used after diluting the low boiling point solvent by distillation under reduced pressure and diluting with an organic solvent used for dispersion so that the solid content was 20% by mass. Hereinafter, the amounts of the pigment dispersant and the fixing resin used represent solid content conversion values.

Example 1
<< Preparation of non-aqueous inkjet ink >>
[Preparation of Ink 1]
<Preparation of pigment dispersion 1>
C. I. 9 parts of Pigment Blue 15: 3 (hereinafter abbreviated as PB15: 3), 1 part of Solsperse 5000 (a copper phthalocyanine pigment derivative having an acidic group, manufactured by Lubrizol), and Azisper PB-822 (Ajinomoto Co., Ltd.) as a pigment dispersant 5 parts of fine techno), 10 parts of dimethyl sulfoxide (S-1) as compound (A), 60 parts of diethylene glycol diethyl ether and 15 parts of ethylene glycol diacetate as solvent (C), and a diameter of 0 Dispersion was performed using a horizontal bead mill (System Zeta Mini, manufactured by Ashizawa Corporation) filled with 60% by volume of 5 mm zirconia beads, and then the zirconia beads were removed to obtain Pigment Dispersion 1.

<Preparation of resin solution 1>
10 parts dimethyl sulfoxide as compound (A), 10 parts dimethyl succinate (D-1) as compound (B), 65 parts diethylene glycol diethyl ether and 5 parts ethylene glycol diacetate as solvent (C), fixing As a resin, 10 parts of vinyl chloride-vinyl acetate copolymer (trade name VYHD, number average molecular weight 22000, manufactured by Dow Chemicals) synthesized by a solution polymerization method was mixed and dissolved to prepare a resin solution 1. .

<Preparation of non-aqueous inkjet ink>
While stirring 50 parts of the resin solution 1, 50 parts of the pigment dispersion 1 was added and mixed, and then filtered through a 0.8 μm filter to obtain ink 1.

[Preparation of inks 2-43]
Table 1 shows the type of pigment, the type of fixing resin, the type and addition amount of compound (A), the type and addition amount of compound (B), the type and addition amount of solvent (C), and the type and addition amount of other solvents. Inks 2 to 43 were prepared in the same manner as the ink 1 except that it was changed as shown in Table 2.

  In addition, the detail of each additive described by the abbreviation in Table 1 and Table 2 is as follows. In addition, the numerical value of content of Table 1 and Table 2 is the mass%.

[Pigment]
PB15: 3 C.I. I. Pigment Blue 15: 3
PY150 C.I. I. Pigment Yellow 150
PR122 C.I. I. Pigment Red 122
CB carbon black [fixing resin]
PVC: Solution polymerization vinyl chloride-vinyl acetate copolymer (trade name VYHD, manufactured by Dow Chemicals)
Acrylic: Methyl methacrylate-n-butyl methacrylate copolymer (trade name Paraloid B-60, manufactured by Rohm & Haas)
[Compound (A)]
S-1: Dimethyl sulfoxide S-2: Di-n-propyl sulfoxide S-3: Di-n-butyl sulfoxide S-4: Diphenyl sulfoxide S-5: Tetramethylene sulfoxide S-6: Dimethyl sulfone S-7: Di -N-propylsulfone S-8: methylisopropylsulfone S-9: methylhydroxyethylsulfone S-10: sulfolane [compound (B)]
D-1: Dimethyl succinate D-2: Dimethyl glutarate D-3: Dimethyl adipate D-4: Dimethyl oxalate D-5: Dimethyl malonate D-6: Diethyl malonate D-7: Dimethyl pimelate D -8: dimethyl sebacate D-9: propyl succinate D-10: t-butyl succinate [solvent (C)]
DEGDEE: Diethylene glycol diethyl ether EGDAc: Ethylene glycol diacetate DEGDME: Diethylene glycol dimethyl ether PGDAc: Propylene glycol diacetate DPGDEE: Dipropylene glycol diethyl ether DPGDME: Dipropylene glycol dimethyl ether [Other solvents]
EGBEAc: ethylene glycol monobutyl ether acetate NMP: N-methylpyrrolidone TEGDME: tetraethylene glycol dimethyl ether << Evaluation of non-aqueous inkjet ink >>
Each ink prepared above was evaluated for odor resistance according to the following method.

[Evaluation of odor resistance]
About 1 to 50 of each of the inks 1 to 39 are put into a 500 ml polyethylene bottle, and the odor perception by 10 subjects is evaluated. If it is determined that the odor is almost odorless, 5 points are given. Points were assigned at each stage, and odor resistance was evaluated according to the following criteria.

A: The average score of 10 subjects is 4.0 points or more. ○: The average score of 10 subjects is 3.0 points or more and less than 4.0 points. Δ: The average score of 10 subjects is 2.0 points or more and less than 3.0 points x: The average score of 10 subjects is less than 2.0 points.

<Evaluation of formed image>
[Image formation]
Each ink is supplied to an on-demand type ink jet printer equipped with a piezo head having a nozzle diameter of 28 μm, a drive frequency of 15 kHz, a nozzle number of 512, a minimum liquid amount of 14 pl, a nozzle density of 180 dpi, and a heater having a maximum recording density of 1440 × 1440 dpi. Was loaded. Next, each ink was ejected, and a solid image of 10 cm × 10 cm was recorded on JT5929PM (manufactured by Mactac) which is a recording medium made of polyvinyl chloride. During printing, the recording medium was heated from the back side, and the heater temperature was set so that the surface temperature of the recording medium during image recording was 45 ° C. The surface temperature of the recording medium was measured using a non-contact thermometer (IT-530N type, manufactured by Horiba, Ltd.).

[Evaluation of image]
According to the above method, each image produced from the inks 1 to 43 was evaluated according to the following method. In all cases, the performance of Δ or higher was regarded as an acceptable level.

<Evaluation of scratch resistance 1>
The image surface recorded on polyvinyl chloride was rubbed with dry cotton while applying a load of 300 g / cm ^{2, and} scratch resistance 1 was evaluated according to the following criteria.

◎: Image hardly changes even after rubbing 61 times or more ○: Slight scratch remains at the stage of rubbing 60 times, but hardly affects the image density Δ: Image density decreases during rubbing 30 to 59 times × : Image density decreases while rubbing less than 30 times.

<Evaluation of alcohol wiping resistance>
The image recorded on polyvinyl chloride was rubbed with cotton containing a 2: 1 mixed solution of ethanol and water, and the alcohol wiping resistance was evaluated according to the following criteria.

A: Image hardly changes even after rubbing 41 times or more ○: Slight scratch remains at the stage of rubbing 40 times, but hardly affects the image density Δ: Image density decreases during rubbing 20 to 39 times × : Image density decreases while rubbing less than 20 times.

(Evaluation of dryness)
After printing so that the amount of ink per unit area printed on a solid image is twice the normal amount by the same method as the image forming method described above, the solid image surface after printing is rubbed with a finger, and the following criteria are used: The dryness was evaluated according to

◎: The time when the image cannot be taken even if it is rubbed with a finger is less than 5 minutes measured immediately after image recording. ○: The time when the image is not taken even if rubbed with a finger is measured after immediately after image recording is 5 minutes or more. Less than 10 minutes Δ: The time at which an image cannot be taken even when rubbed with a finger is 10 minutes or more and less than 15 minutes as measured immediately after image recording. It takes 15 minutes or more from immediately after image recording.

  Table 3 shows the results obtained as described above.

  As is clear from the results shown in Table 3, the ink having the structure defined in the present invention is synergistically excellent in quick-drying compared to the comparative example, and the odor resistance of the ink, the scratch resistance of the image, It turns out that it is excellent in all the characteristics of alcohol wiping resistance.

Example 2
<Preparation of ink>
[Preparation of inks 44 to 54]
In the preparation of the ink 1 described in Example 1, the type of pigment, the type and addition amount of the fixing resin, the type and addition amount of the compound (A), the type and addition amount of the compound (B), the solvent (C) Inks 44 to 54 were prepared in the same manner except that the types and addition amounts thereof and other solvent types and addition amounts thereof were changed as shown in Table 4.

  In addition, the detail of each additive described by the abbreviation in Table 4 is as follows. In addition, the numerical value of content described in Table 4 is mass%.

[Fixing resin]
mPVC: solution polymerization vinyl chloride-vinyl acetate-vinyl alcohol copolymer (trade name VAGD, number average molecular weight 22000, manufactured by Dow Chemicals)
sPVC: Suspension polymerization vinyl chloride-vinyl acetate-vinyl alcohol copolymer (trade name SOLBIN-AL, number average molecular weight 22000, manufactured by Nissin Chemical)
mPVC-2: Solution polymerization vinyl chloride-vinyl acetate-hydroxyalkyl acrylate copolymer (trade name VAGF, number average molecular weight 33000, manufactured by Dow Chemicals)
mPVC-3: solution polymerization vinyl chloride-vinyl acetate-hydroxyalkyl acrylate copolymer (trade name VAGC, number average molecular weight 24000, manufactured by Dow Chemicals)
mPVC-4: Solution polymerization vinyl chloride-vinyl acetate-hydroxyalkyl acrylate copolymer (trade name VROH, number average molecular weight 15000, manufactured by Dow Chemicals)
Except for the fixing resin and other solvents, the details of the additives described in abbreviations in Table 4 are the same as those in Example 1.

<Evaluation of ink>
For each of the inks prepared as described above, evaluation of emission was performed according to the following method, and odor resistance was evaluated by the same method as in Example 1.

(Evaluation of light emission)
Piezo head having nozzle diameter of 28 μm, driving frequency of 15 kHz, number of nozzles of 512, minimum liquid amount of 14 pl, nozzle density of 180 dpi (dpi represents the number of dots per 2.54 cm), and Japanese Patent Application Laid-Open No. 2002-363469 Using the strobe light emission type ink flight observation device shown in FIG. 2, the ejection cycle and the light emission cycle are synchronized, and the flight status of each ink is monitored by a CCD camera, and the emission property in an environment of 23 ° C. and 55% RH is observed. Evaluation was made according to the following criteria.

A: Ink droplets are ejected normally, and even if the ejection is stopped for 3 minutes and then resumed, no abnormalities such as bending, chipping, or speed variation occur. O: The ink droplets are ejected normally and emitted. No problem occurs even after restarting after stopping for 1 minute, but there is a nozzle that bends and has a speed variation when restarting after stopping for 3 minutes. Δ: Ink droplets are ejected normally, but ejection There are nozzles that bend and vary in speed when restarted after being stopped for 1 minute. ×: There are nozzles that are difficult to normally eject ink droplets and cause bending, and many nozzles when ejection is resumed after stopping for 1 minute. Bending, speed variation, and missing parts <Evaluation of formed image>
Each image is formed from the inks 40 to 47 in the same manner as described in Example 1, and according to the following method, the scuff resistance 2 is evaluated, and the alcohol wiping resistance is determined in the same manner as in Example 1. Evaluation was performed. In all cases, the performance of Δ or higher was regarded as an acceptable level.

<Evaluation of scratch resistance 2>
The image surface recorded on polyvinyl chloride was rubbed with dry cotton while applying a load of 300 g / cm ^{2, and} scratch resistance 2 was evaluated according to the following criteria. Note that the evaluation of the scratch resistance 2 is more severe than the evaluation of the scratch resistance 1 of Example 1, and therefore the evaluation conditions are more severe.

◎: Image hardly changes even after rubbing 101 times or more ○: Slight scratch remains at the stage of rubbing 100 times, but hardly affects the image density Δ: Image density decreases during rubbing 50 to 99 times X: Image density decreases while rubbing less than 50 times (Dryness evaluation)
As in Example 1, after printing so that the amount of ink per unit area printed on a solid image is twice the normal amount, the solid image surface after printing is rubbed with a finger, and the same as in Example 1 Dryness was evaluated according to criteria.

  Table 5 shows the results obtained as described above.

  As is apparent from the results shown in Table 5, the ink having the configuration defined in the present invention is excellent in quick-drying properties, and has good ink emission and odor properties, image scratch resistance, and alcohol wiping resistance. I understand that. Further, it can be seen that by using a resin synthesized by a solution polymerization method as the fixing resin, more resin can be contained in the ink without affecting the light emission property, and the scratch resistance is further improved.

Example 3
Using the inks 5, 37, 38, and 39 prepared in Example 1, images were formed using the recording media described below instead of polyvinyl chloride as the recording medium, and the method described in Example 1 was used. In the same manner as above, image scratch resistance, alcohol wiping resistance, and drying properties were evaluated, and the results are shown in Table 6.

PET: Polyethylene terephthalate sheet PP: Polypropylene sheet ABS: Acrylonitrile, butadiene, styrene copolymer sheet PC: Polycarbonate sheet POM: Polyoxymethylene resin sheet PA: Polyacrylate PI: Polyimide PVC: Polyvinyl chloride PE: Polyethylene

  As is apparent from the results shown in Table 6, the ink having the constitution defined in the present invention is a recording comprising a resin base material containing no plasticizer other than polyvinyl chloride and a non-absorbing inorganic base material as constituent elements. It can be seen that excellent image scratch resistance, alcohol wiping resistance, and drying properties are good even when an image is formed on the medium.

Claims (7)

Pigments,
A fixing resin;
At least one compound (A) selected from the compound group represented by the following general formulas (1) and (2) is 1.5% by mass or more and 30% by mass or less based on the total mass of the ink ;
Containing at least one compound (B) selected from the group consisting of compounds represented by the following general formula (3),

[Wherein, R ¹ and R ² each independently represents an alkyl group, a cyclohexyl group, or a phenyl group having 1 to 6 carbon atoms, each of which may be substituted, and R ¹ and R ² are bonded to each other. May form a ring. ]

[Wherein R ³ and R ⁴ each independently represent an alkyl group, a cyclohexyl group, or a phenyl group, each having 1 to 6 carbon atoms, which may be substituted, and R ³ and R ⁴ are bonded to each other. May form a ring. ]
General formula (3)
_{^{R 5 -OOC (CH 2) nCOO}} -R 6
[Wherein, R ⁵ and R ⁶ are each independently a linear or branched alkyl group having 1 to 5 carbon atoms, and two alkyl groups in the molecule may be the same or different. In the formula (3), n is an integer from 0 to 8. ]
The fixing resin is a vinyl chloride-vinyl acetate copolymer, a vinyl chloride-vinyl acetate-maleic anhydride copolymer, a vinyl chloride-vinyl acetate-vinyl alcohol copolymer having a number average molecular weight in the range of 10,000 to 30,000, and non-aqueous inkjet inks, wherein at least one Tanedea Rukoto selected from the group consisting of hydroxy alkyl acrylate copolymer - vinyl chloride - vinyl acetate. The non-aqueous inkjet ink according to claim 1, further comprising a solvent (C) comprising one or more compounds selected from the group of compounds represented by the following general formulas (4) and (5).

[Wherein, R ⁷ and R ⁸ each represent a methyl group or an ethyl group, and OX ¹ represents an oxyethylene group or an oxypropylene group. ]

[Wherein, R ⁹ and R ¹⁰ each represent a methyl group or an ethyl group, and OX ² represents an oxyethylene group or an oxypropylene group. ]   The non-aqueous inkjet ink according to claim 2, wherein the total content of the solvent (C) and the content of the compound (B) is 50% by mass or more and 85% by mass or less.   The solvent (C) is at least one selected from diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, ethylene glycol diacetate, and propylene glycol diacetate. The non-aqueous inkjet ink as described.   The non-aqueous inkjet ink according to claim 1, wherein the fixing resin is a resin synthesized by a solution polymerization method. The compound represented by Formula (3) is selected from the group consisting of dimethyl succinate, dimethyl glutarate, and dimethyl adipate, according to any one of claims 1 to 5. Non-aqueous inkjet ink.   An inkjet recording method for recording an image on a recording medium using the non-aqueous inkjet ink according to any one of claims 1 to 6, wherein the recording medium does not contain polyvinyl chloride or a plasticizer. An inkjet recording method comprising at least one selected from recording media comprising a substrate and a non-absorbing inorganic substrate as a constituent element.