JP2007326931A - Method for producing nonaqueous inkjet ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a nonaqueous inkjet ink having good ink preservation stability, excellent in satellite resistance and decap resistance, and having excellent fixity on a soft polyvinyl chloride printing medium. <P>SOLUTION: The method for producing a nonaqueous inkjet ink comprising at least a pigment, a resin and an organic solvent comprises a step for dispersing the pigment with the resin, wherein the resin is a polyvinyl chloride-based resin having at least one selected from sulfonic group, sulfate group and alkali metal salts thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a novel non-aqueous inkjet ink.

  In recent years, the inkjet recording method can be easily and inexpensively created images, and thus has been applied to various printing fields such as photographs, various printing, marking, and special printing such as color filters.

  Ink jet inks used in such an ink jet recording method include water-based inks mainly containing water, oil-based inks mainly containing non-volatile solvents, non-aqueous inks mainly containing volatile solvents, and room temperature. There are a plurality of inkjet inks, such as a hot melt ink that heats and melts solid ink for printing, and an actinic ray curable ink that is cured by actinic rays such as light after printing.

  On the other hand, recording media made of soft polyvinyl chloride are used in a wide range of applications such as outdoor postings that require long-term weather resistance and printed materials that require adhesion to curved objects. 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.

  As the ink-jet ink for a recording medium made of soft polyvinyl chloride, an ink-jet ink using a solvent having solubility in soft polyvinyl chloride and a resin having fixability to soft polyvinyl chloride is disclosed ( For example, see Patent Documents 1 and 2). As the fixing resin, vinyl chloride resins such as vinyl chloride-vinyl acetate copolymer and vinyl chloride-vinyl acetate-vinyl alcohol copolymer are used because of their good fixability.

  In a non-aqueous inkjet ink using such a vinyl chloride fixing resin, a pigment is dispersed with a polymer dispersant such as an amine ester, and a diluent containing a vinyl chloride resin is added to the ink. Is generally produced.

  However, such a method for producing an ink-jet ink has a problem in that the storage stability of the ink tends to be lowered due to a poor compatibility between the polymer dispersant and the vinyl chloride resin as the fixing resin. Further, the resin tends to deteriorate the satellite characteristics and the decap characteristics when the ink is emitted, but there is a problem that it is difficult to reduce the total amount of the resin by separately using the polymer dispersant and the fixing resin.

On the other hand, a method is disclosed in which an acrylic resin having an acid value in a specific range is used as a dispersant and a fixing resin (see, for example, Patent Document 3). However, acrylic resins are generally not preferred because they are not as good in fixing properties as vinyl chloride resins. Further, the carboxylic acid group, which is a polar functional group of acrylic acid, has insufficient dispersion stability of the pigment.
JP 2005-15672 A Japanese Patent Laid-Open No. 2005-60716 JP 2004-75983 A

  The present invention has been made in view of the above-mentioned problems, and its purpose is that the storage stability of the ink is good, the satellite is resistant to satellites and decaps, and the recording medium is made of soft polyvinyl chloride. An object of the present invention is to provide a method for producing a non-aqueous inkjet ink having excellent fixing properties.

  The above object of the present invention is achieved by the following configurations.

  1. In the method for producing a non-aqueous ink-jet ink containing at least a pigment, a resin and an organic solvent, the resin has a step of dispersing the pigment with the resin, and the resin is selected from a sulfonic acid group, a sulfate group, and an alkali metal salt thereof. A method for producing a non-aqueous inkjet ink, which is a vinyl chloride resin having at least one.

  2. 2. The method for producing a non-aqueous inkjet ink according to 1, wherein at least one of the organic solvents is 1,3-dimethyl-2-imidazolidinone.

  According to the present invention, there is provided a method for producing a non-aqueous ink jet ink having excellent ink storage stability, excellent satellite resistance and decap resistance during emission, and excellent fixability to a recording medium made of soft polyvinyl chloride. We were able to.

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

  As a result of intensive studies in view of the above problems, the present inventor has obtained a step of dispersing the pigment with the resin in a method for producing a non-aqueous inkjet ink containing at least a pigment, a resin, and an organic solvent. Is a vinyl chloride resin having at least one selected from a sulfonic acid group, a sulfuric acid group and an alkali metal salt thereof, and the storage stability of the ink is good by the method for producing a non-aqueous inkjet ink, It has been found that a method for producing a non-aqueous ink jet ink excellent in satellite resistance and decap resistance at the time of emission and excellent in fixability to a recording medium made of soft polyvinyl chloride can be realized.

  The present inventor has achieved the object effect of the present invention by the method for producing a non-aqueous ink jet ink (hereinafter also referred to as ink jet ink or simply ink) having the configuration defined in the present invention as follows. I guess.

  Generally, as a fixing resin to soft polyvinyl chloride, a vinyl chloride resin is excellent because of its high affinity. By introducing a sulfonic acid group, a sulfuric acid group or an alkali metal salt thereof into this vinyl chloride resin, the adsorptivity to the pigment is excellent, so that the pigment can be dispersed without using a polymer dispersant. Become. In addition, sulfonic acid groups, sulfuric acid groups, or alkali metal salts thereof are more polar than carboxylic acids such as acrylic acid that have been studied, and can disperse pigments more stably.

  Furthermore, since vinyl chloride resins having sulfonic acid groups, sulfuric acid groups, or alkali metal salts thereof serve as both a dispersant and a fixing agent, dispersion due to a decrease in compatibility when separate resins are used as the dispersant and the fixing resin. No stability degradation occurs.

  Also, the resin usually has an adverse effect on the emission of ink, but since the total amount of resin in the ink can be reduced as a result of the combined use of a dispersant and a fixing agent, satellite characteristics and decap characteristics are improved. I think that the.

  Details of the present invention will be described below.

  The resin according to the present invention is a vinyl chloride resin having a sulfonic acid group, a sulfuric acid group, or an alkali metal salt thereof. The number average molecular weight of the resin is preferably in the range of 10,000 to 30,000. If the molecular weight is lower than this, the fixability to soft polyvinyl chloride is lowered, which is not preferable. When the molecular weight is higher than the range specified above, the viscosity of the ink becomes too high, which is not preferable because it becomes an obstacle to stable ink ejection.

  The resin composition according to the present invention includes vinyl chloride-vinyl alcohol copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, vinyl chloride-vinyl acetate-vinyl alcohol copolymer. The vinyl chloride copolymer such as a coalescent is preferably contained as a vinyl monomer unit having a sulfonic acid group, a sulfuric acid group or an alkali metal salt thereof in the side chain.

  Examples of vinyl monomers having a sulfonic acid group, a sulfuric acid group, or an alkali metal salt thereof in the side chain include vinyl sulfonic acid, methyl vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, (meth) acrylic acid-2- Ethyl sulfonate, 2-acrylamido-2-methylpropanesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, (meth) acrylic acid-2-ethylsulfate, 3-allyloxy-2-hydroxypropanesulfuric acid or a sodium salt thereof And potassium salts.

  A vinyl chloride resin having a sulfonic acid group, a sulfuric acid group or an alkali metal salt thereof can be obtained as a commercial product, and examples thereof include MR110 (manufactured by Nippon Zeon Co., Ltd.), UCARMMAG 569 (manufactured by Dow Chemical Co., Ltd.) and the like. .

  The method for producing an inkjet ink of the present invention is characterized by having a step of dispersing the pigment with the resin according to the present invention.

  The dispersion of the pigment by the resin according to the present invention is preferably used after being dispersed by a disperser. Dispersers include conventionally known dispersion devices such as ball mills, sand mills, attritors, roll mills, agitators, Henschel mixers, continuous kneaders, pressure kneaders, colloid mills, ultrasonic homogenizers, pearl mills, wet jet mills, paint shakers, etc. Can be used.

  The average particle size of the pigment dispersion used in the ink according to 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.

  The inkjet ink of the present invention contains an organic solvent together with a resin.

  As a characteristic of the solvent that can be used in the present invention, it is preferable to use a solvent that dissolves soft polyvinyl chloride and a solvent that does not dissolve but has a high swelling property.

  Examples of the organic solvent that dissolves soft polyvinyl chloride include 1,3-dimethyl-2-imidazolidinone, γ-butyrolactone, and N-methylpyrrolidone. Among these organic solvents, 1,3-dimethyl-2-imidazolidinone is preferable from the viewpoint of the dispersion stability of the pigment dispersion because of the high solubility of the resin according to the present invention.

  The content of the organic solvent that dissolves the soft polyvinyl chloride is preferably in the range of 3 to 25% by mass in the ink. If the content is lower than this, the fixability to soft polyvinyl chloride is lowered. A content higher than this is not preferable because it easily damages the printer member and the head member.

  Examples of the organic solvent having a large swelling property of soft polyvinyl chloride include, for example, alkylene glycol monoalkyl ethers such as diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, and ethylene glycol diethylene ether. Alkylene glycol dialkyl ethers such as butyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, dipropylene glycol diethyl ether, tetraethylene glycol dimethyl ether, alkylene glycol acetates such as diethylene glycol acetate, alkylene glycols such as ethylene glycol diacetate and propylene glycol diacetate Diacetates, ethylene glycol monobutyl ether acetate, alkylene glycol monoalkyl ether acetates such as propylene glycol monomethyl ether acetate are preferable. These solvents have a property of swelling polyvinyl chloride as compared with glycols, polyols, and glycerin, and even if they are contained in the ink, they hardly affect the drying property.

  Among the organic solvents, it is preferable to use an organic solvent having a boiling point of 180 ° C. or higher and lower than 250 ° C. and a surface tension of 20 mN / m or higher and 35 mN / m or lower. By setting the boiling point of the organic solvent to 180 ° C. or higher, the ink emission property tends to be good, and by setting it to less than 250 ° C., the drying property when printed on polyvinyl chloride tends to be good. Further, the use of an organic solvent having a surface tension of 20 mN / m or more and 35 mN / m or less tends to improve the gloss of an image recorded on polyvinyl chloride. Specific examples of such organic solvents include ethylene glycol monobutyl ether acetate, ethylene glycol diacetate, diethylene glycol diethyl ether, diethylene glycol monobutyl ether acetate, triethylene glycol dimethyl ether, propylene glycol diacetate, dipropylene glycol monomethyl ether, dipropylene glycol. Examples thereof include monomethyl ether acetate.

  The ink-jet ink of the present invention contains a pigment as a color material together with a resin and an organic solvent.

  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, it is preferable to use the following pigments 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 7, 36,
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.

  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.

  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, a thermal type) Any ejection method such as an ink jet type or a bubble jet (registered trademark) type 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, so it is more preferable to increase the surface temperature for recording. 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.

  As a recording medium used in the ink jet recording method of the present invention, polyvinyl chloride is used. Specific examples of the recording medium made of polyvinyl chloride include SOL-371G, SOL-373M, SOL-4701 (manufactured by Big Technos Co., Ltd.), glossy vinyl chloride (manufactured by 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, manufactured by Kyo Show Osaka Co., Ltd.), BUS MARK V400 F vinyl, LITEcal V-600F vinyl (above, manufactured by Flexcon), FR2 (manufactured by Hanwha), LLBAU13713, LLSP20133 (above, manufactured by Sakurai Co., Ltd.), P-370B, P-400M (above, manufactured by Kambo Plus Co., Ltd.), S02P, S12P, S13P, S14P, S22P, S24P, 34P, S27P (manufactured by Grafityp), P-223RW, P-224RW, P-249ZW, P-284ZC (manufactured by Lintec Corporation), LKG-19, LPA-70, LPE-248, LPM-45 LTG-11, LTG-21 (manufactured by Shinsei Co., Ltd.), MPI 3023 (manufactured by Toyo Corporation), Napoleon Gloss PVC (manufactured by Futaki Electronics Co., Ltd.), JV-610, Y-114 ( As described above, manufactured by ICC Corporation), NIJ-CAPVC, NIJ-SPVCGT (hereinafter, manufactured by Nichie Corporation), 3101 / H12 / P4, 3104 / H12 / P4, 3104 / H12 / P4S, 9800 / H12 / P4, 3100 / H12 / R2, 3101 / H12 / R2, 3104 / H12 / R 2, 1445 / H14 / P3, 1438 / One Way Vision (manufactured by Inetrcoat), JT5129PM, JT5728P, JT5822P, JT5829P, JT5829R, JT5829PM, JT5829RM, JT5929PM (above, manufactured by Mactac, MP1100, MP1100 MPI2001, MPI2002, MPI3000, MPI3021, MPI3500, MPI3501 (above, manufactured by Avery), AM-101G, AM-501G (above, manufactured by Ginichi Co., Ltd.), FR2 (manufactured by Hanwha Japan Co., Ltd.), AY-15P, AY-60P, AY-80P, DBSP137GGH, DBSP137GGL (above, manufactured by Insight Inc.), SJT-V200F, SJ T-V400F-1 (above, manufactured by Hiraoka Oryome 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), SP300 GWF, SPCLEARAD vinyl l (above, manufactured by Catalina), RM-SJR (produced by Ryoyo Shoji Co., Ltd.), Hi Lucky, New Lucky PVC (above, produced by LG), SIY-110, SIY-310, SIY-320 (above, Sekisui Chemical) Industrial Co., Ltd.), PRINT MI Frontlit, PRINT XL Lightweight banner (above, manufactured by Endutex), RIJET 100, RIJET 145, RIJET165 (above, manufactured by Ritrama), NM-SG, NM-SM Co., Ltd. Manufactured), LTO3GS (manufactured by Lucio Co., Ltd.), easy print 80, performance print 80 (manufactured by Jetgraph Co., Ltd.), DSE 550, DSB 550, DSE 800G, DSE 802/137, V250WG, 300WG, V350WG (manufactured by Hexis Ltd.), Digital White 6005PE, 6010PE (or, Multifix Co., Ltd.).

  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.

<Preparation of inkjet ink>
[Preparation of Ink 1]
C. I. 12 parts of Pigment Red 122, 15 parts of vinyl chloride resin MR110 (manufactured by ZEON CORPORATION), 15 parts of N-methylpyrrolidone and 58 parts of diethylene glycol diethyl ether were mixed, and zirconia beads having a diameter of 0.5 mm were mixed at a volume ratio. Dispersion was performed using a horizontal bead mill (System Zeta Mini manufactured by Ashizawa Co., Ltd.) filled with 60%, and then zirconia beads were removed to obtain a pigment dispersion.

  Next, a diluted solution consisting of 5 parts of N-methylpyrrolidone and 95 of diethylene glycol diethyl ether was prepared.

  Next, a diluted solution was added while stirring 33 parts of the pigment dispersion, and then filtered through a 0.8 μm filter to obtain ink 1. The ratio of each component in ink 1 is shown below.

C. I. Pigment Red 122 4 parts MR110 5 parts Diethylene glycol diethyl ether 86 parts N-methylpyrrolidone 5 parts [Preparation of ink 2]
Ink 2 was prepared in the same manner as in Preparation of Ink 1 except that the same amount of 1,3-dimethyl-2-imidazolidinone was used instead of N-methylpyrrolidone.

[Preparation of ink 3]
Ink 3 was prepared in the same manner as in Preparation of Ink 1 except that the same amount of UCARMMAG 569 (manufactured by Dow Chemical Co., Ltd.) was used instead of MR110.

[Preparation of Ink 4]
In the preparation of the ink 1, the same amount of the resin (sulfonic acid group-containing vinyl chloride resin) described in Example 1 of JP-A-60-235814 was used instead of MR110. Ink 4 was prepared.

[Preparation of Ink 5]
In the preparation of the ink 1, the same amount of the resin described in Example 3 of JP-A-60-235814 (sodium sulfonate-containing vinyl chloride resin) was used instead of MR110. Ink 5 was prepared.

[Preparation of Ink 6]
Ink 6 was prepared in the same manner as in the preparation of Ink 1 except that the same amount of resin (potassium sulfate-containing vinyl chloride resin) shown in Synthesis Example 2 of JP-A-3-141020 was used instead of MR110. Was prepared.

[Preparation of ink 7]
Ink 7 was prepared in the same manner as in Preparation of Ink 1 except that the same amount of VMCC (maleic acid-containing vinyl chloride resin: manufactured by Dow Chemical Co.) was used instead of MR110.

[Preparation of ink 8]
Ink 8 was prepared in the same manner as in Preparation of Ink 1 except that the same amount of VMHD (functional group-free vinyl chloride resin: manufactured by Dow Chemical Company) was used instead of MR110.

[Preparation of ink 9]
Ink 9 was prepared in the same manner except that the same amount of resin (carboxylic acid-containing acrylic copolymer) described in Example 1 of JP-A-2004-75983 was used in place of MR110. did.

[Preparation of Ink 10]
C. I. 12 parts of Pigment Red 122, 6 parts of Solspers 20000 (manufactured by Abyssia), 6 parts of 1,3-dimethyl-2-imidazolidinone and 76 parts of diethylene glycol diethyl ether were mixed. Dispersion was performed using a horizontal bead mill (System Zeta Mini, manufactured by Ashizawa) filled with 5 mm of zirconia beads at a volume ratio of 60%, and then the zirconia beads were removed to obtain a pigment dispersion.

  4 parts of 1,3-dimethyl-2-imidazolidinone, 58 parts of diethylene glycol diethyl ether and 5 parts of vinyl chloride resin MR110 (manufactured by Nippon Zeon Co., Ltd.) containing potassium sulfate are mixed and dissolved to obtain a diluted solution. Prepared.

  Next, the diluted solution was added while stirring 33 parts of the pigment dispersion, and then filtered through a 0.8 μm filter to obtain ink 10. The ratio of each component in the ink 10 is shown below.

C. I. Pigment Blue 15: 3 4 parts Solsperse 20000 2 parts Diethylene glycol diethyl ether 84 parts 1,3-dimethyl-2-imidazolidinone 5 parts MR110 5 parts [Preparation of Ink 11]
In the preparation of the ink 10, the ink 11 was prepared in the same manner except that the same amount of the resin (rubonic acid-containing acrylic copolymer) described in Example 10 of JP-A-2004-75983 was used instead of MR110. Was prepared.

[Preparation of Ink 12]
Ink 12 was prepared in the same manner as in the preparation of Ink 10 except that the same amount of VMHD (functional group-free vinyl chloride resin: manufactured by Dow Chemical Company) was used instead of MR110.

<Evaluation of ink>
Each of the inks prepared above was stored at 60 ° C. for 12 hours and then stored at −10 ° C. for 12 hours, and then stored for 2 months, and then subjected to the following evaluations. Ink 8 was poorly dispersed and was excluded from the evaluation.

(Viscosity stability)
The viscosity of each ink before and after storage was measured, and the viscosity stability was evaluated according to the following criteria.

A: No change in ink viscosity was observed after 2 months storage. B: After 2 months storage, the ink viscosity increased by 1-2%. C: After 2 months storage, the ink viscosity was 3-5. D: Increased by 6-10% after 2 months storage E: Increased by more than 11% ink viscosity after 2 months storage (Evaluation of satellite resistance)
Piezo-type head having a nozzle diameter of 28 μm, a nozzle number of 512, a minimum liquid amount of 14 pl, a nozzle density of 180 dpi (dpi in the present invention 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 flying observation apparatus shown in FIG. 2, the ejection cycle and the light emission cycle were synchronized, and the flying state of each ink was monitored by a CCD camera. In an environment of 23 ° C. and 55% RH, the satellite length at a driving frequency of 10 kHz, a droplet speed of 6 m / sec, and a distance of 1 mm from the nozzle was measured before and after the high temperature treatment.

A: Ink after storage with respect to ink before storage, no increase in satellite length B: Ink after storage with respect to ink before storage, the increase rate of satellite length was 1 to 10% C: The ink after storage with respect to the ink before storage, and the increase rate of the satellite length was 11 to 20%. D: The ink after storage with respect to the ink before storage, and the increase rate of the satellite length was E: It was an ink after storage with respect to the ink before storage, and the increase rate of the satellite length was 31% or more (evaluation of decap resistance)
Using a piezo-type head having a nozzle diameter of 28 μm, a nozzle number of 512, a minimum liquid amount of 14 pl, a nozzle density of 180 dpi, and a strobe light emission type ink flight observation apparatus described in FIG. 2 of Japanese Patent Laid-Open No. 2002-363469, an ejection cycle The emission cycle of each ink was monitored by a CCD camera while synchronizing the light emission period. In the environment of 23 ° C. and 55% RH, the emission at the drive frequency of 10 kHz and the droplet velocity of 6 m / sec was interrupted, and the time until the occurrence of the lack of emission when restarted was evaluated as a decap.

A: Ink after storage with respect to ink before storage, there was no change in the time until ejection failure occurred. B: Ink after storage with respect to ink before storage, until ejection failure occurred. The time was shortened by 1 to 10%. C: The ink after storage was saved with respect to the ink before storage, and the time until ejection failure occurred was shortened by 11 to 20%. D: The ink before storage was stored after the storage. E: The time until ejection failure occurred was reduced by 21 to 30%. E: The time after ejection failure occurred was reduced by 31% or more with the ink after storage compared to the ink before storage (fixing) Sex evaluation)
<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 driving frequency of 18 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 storage treatment and untreated ink were emitted to a recording medium made of polyvinyl chloride, JT5929PM (manufactured by Mactac), and a solid image of 10 cm × 10 cm was recorded. During printing, the recording medium was heated from the back side and controlled with a heater so that the surface temperature of the recording medium during image recording was 40 ° C. The surface temperature of the recording medium was measured using a non-contact thermometer (IT-530N type, manufactured by Horiba, Ltd.).

<Evaluation of scratch resistance>
The image recorded on polyvinyl chloride was rubbed with dry cotton (Kanakin No. 3), and scratch resistance was evaluated according to the following criteria.

A: Ink image after storage with respect to ink image before storage, no peeling of image was observed B: Ink image after storage with respect to ink image before storage, 1 to 10% of image peeled C: Storage 11 to 20% of the image was peeled off after the storage with respect to the previous ink image D: 21 to 30% of the image was peeled off after the storage with respect to the ink image before the storage E: Ink before storage Table 1 shows the results obtained by removing 31% or more of the ink image after storage with respect to the image.

  As is clear from the results shown in Table 1, the non-aqueous inkjet ink produced by the method defined in the present invention has better ink storage stability than the comparative example, and it can be used for a long time in a high / low temperature environment. It can be seen that even after storage, it has excellent satellite resistance and decap resistance at the time of emission, and is excellent in fixing property to a recording medium made of soft polyvinyl chloride.

Claims (2)

In the method for producing a non-aqueous ink-jet ink containing at least a pigment, a resin and an organic solvent, the resin has a step of dispersing the pigment with the resin, and the resin is selected from a sulfonic acid group, a sulfate group, and an alkali metal salt thereof. A method for producing a non-aqueous inkjet ink, which is a vinyl chloride resin having at least one. The method for producing a non-aqueous inkjet ink according to claim 1, wherein at least one of the organic solvents is 1,3-dimethyl-2-imidazolidinone.