JP2010174055A - Inkjet recording ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording ink excellent in color developability, stability and fixability, and especially excellent as an inkjet recording ink for textiles. <P>SOLUTION: The inkjet recording ink comprises a dispersion which has an average particle diameter of 50 to 300 nm and is prepared by dispersing a pigment with a polymer comprising ≥45 wt.% of benzyl acrylate, ≤15 wt.% of methacrylic acid and/or acrylic acid, and ≥5 wt.% of a fluorine-containing (meth)acrylic monomer as constituents. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ink for ink jet recording which is excellent in color developability, stability and fixability, and particularly excellent as an ink jet recording ink for textiles.

  Ink used for inkjet recording has no bleeding, good drying properties, can be printed uniformly on the surface of various recording media, and can be used for multi-color printing such as color printing. Characteristics such as the fact that adjacent colors do not mix in printing are required.

  In conventional inks, many of the inks that use pigments, in particular, have been studied to ensure the print quality by suppressing ink wetting on the paper surface mainly by suppressing penetrability and keeping ink droplets near the paper surface. Made and put to practical use. However, with ink that suppresses wetting of paper, there is a large difference in bleeding due to differences in the type of paper, and especially with recycled paper that contains various paper components, there is bleeding due to differences in the wetting characteristics of each component. appear. In addition, such an ink has a problem that it takes time to dry the printing, and there is a problem that adjacent colors are mixed in multicolor printing such as color printing, and further, a pigment is used as a coloring material. Ink also has a problem that the abrasion resistance deteriorates because the pigment remains on the surface of paper or the like.

  In order to solve such problems, attempts have been made to improve the permeability of ink into paper. Addition of diethylene glycol monobutyl ether (see Patent Document 1), Surfynol 465, which is an acetylene glycol-based surfactant. The addition of Nissin Chemical (see Patent Document 2) or the addition of both diethylene glycol monobutyl ether and Surfynol 465 (see Patent Document 3) has been studied. In addition, the use of diethylene glycol ethers for ink has been studied (see Patent Document 4).

  In addition, in the case of an ink using a pigment, it is generally difficult to improve the ink permeability while ensuring the dispersion stability of the pigment, and the range of selection of the penetrant is narrow. There are also examples using triethylene glycol monomethyl ether (see Patent Document 5) and examples using ethylene glycol, diethylene glycol or triethylene glycol ethers (see Patent Document 6).

  Furthermore, as textiles, there are, for example, those using dyes (see Patent Document 7) and those relating to binders (see Patent Document 8).

US Pat. No. 5,156,675 US Pat. No. 5,183,502 US Pat. No. 5,196,056 US Pat. No. 2,083,372 Japanese Patent Application Laid-Open No. 56-147861 Japanese Patent Laid-Open No. 9-111165 JP 2007-515561 A JP 2007-126635 A

  However, conventional water-based inks have insufficient print quality, particularly as ink-jet recording inks for textiles, have insufficient fixability, and insufficient color density and color developability. In addition, conventional pigment dispersions have low storage stability and are unstable, and when a substance having a hydrophilic part and a hydrophobic part such as a surfactant or glycol ether is present, the adsorption and desorption of the polymer from the pigment is likely to occur. There is a problem that the storage stability of the ink is poor. Ordinary water-based inks require a substance having a hydrophilic part and a hydrophobic part such as a surfactant and glycol ether in order to reduce bleeding on paper. Ink that does not use these substances has insufficient permeability to paper, and there is a problem in that the type of paper is limited in order to perform uniform printing, which tends to cause a reduction in the printed image.

  Further, additives such as those used in the present invention (acetylene glycol and acetylene alcohol surfactants, di (tri) ethylene glycol monobutyl ether, (di) propylene glycol monobutyl ether or 1,2-alkylene) as used in the present invention. If glycol or a mixture thereof is used, long-term storage stability cannot be obtained, and ink re-dissolvability is poor, so that the ink dries and easily clogs at the tip of the nozzle of the inkjet head. It was.

  Accordingly, the present invention solves such problems, and the object thereof is excellent in color developability, stability and fixability, particularly excellent as an inkjet recording ink for textiles, and ink from an inkjet head. Another object of the present invention is to provide an ink for ink jet recording having excellent discharge stability.

  In the inkjet ink of the present invention, 45% by weight or more of benzyl acrylate, 15% by weight or less of methacrylic acid and / or acrylic acid, and 5% by weight or more of a fluorine-containing (meth) acrylic monomer are polymerized. And a dispersion having an average particle size of 50 nm or more and 300 nm or less that enables the pigment to be dispersed in water.

  The present invention has been completed as a result of intensive studies in view of demands for characteristics such as excellent color developability, stability, and fixability, and particularly excellent as an inkjet recording ink for textiles.

  In the inkjet recording ink of the present invention, 45% by weight or more of benzyl acrylate, 15% by weight or less of methacrylic acid and / or acrylic acid, and 5% by weight or more of fluorine-containing (meth) acrylic monomer are polymerized. A dispersion having an average particle size of 50 nm to 300 nm inclusive of a dispersion in which the pigment is dispersible in water using the prepared polymer is characterized.

  The average particle diameter of the pigment dispersion is measured by a light scattering method. If the average particle size of the pigment dispersion by the light scattering method is less than 50 nm, the color developability decreases. On the other hand, when the average particle diameter of the pigment dispersion exceeds 300 nm, the fixing property is lowered. More preferably, it is 60 nm-230 nm.

  The dispersion comprising the ink of the present invention comprises 45% by weight or more of benzyl acrylate, 15% by weight or less of methacrylic acid and / or acrylic acid, and 5% by weight or more of fluorine-containing (meth) acrylic monomer. And are dispersed using a polymerized polymer. The benzyl acrylate that constitutes the above polymer has high color developability as compared with the case where other acrylic acid esters are used due to the polymer Tg and the refractive index. The benzyl acrylate is preferably 50% by weight or more, more preferably 60% by weight or more. The polymer is a polymer of 15% by weight or less of methacrylic acid and / or acrylic acid and 5% by weight or more of a fluorine-containing (meth) acrylic monomer. When methacrylic acid and / or acrylic acid exceeds 15% by weight, the color developability of the inkjet ink tends to be lowered. A preferred range of methacrylic acid and / or acrylic acid is 10% by weight or less. Further, when methacrylic acid and acrylic acid are compared, it is more preferable to use acrylic acid from the viewpoint of fixability. The polymer is characterized in that the blending amount of the fluorine-containing (meth) acrylic monomer is 5% by weight or more in order to improve the abrasion resistance when printed on textiles.

  As fluorine-containing (meth) acrylic monomers, α-trifluoromethylacrylic acid, 2,2,2, -trifluoroethyl (meth) acrylate, 1-adamantyl-α-trifluoromethacrylate, 3-hydroxy-1-adamantyl -Α-trifluoromethacrylate, 2,2,2-trifluoroethyl-α-trifluoromethacrylate, tertiary butyl-α-trifluoromethacrylate, 2,2,3,3-tetrafluoropropyl acrylate, 1H, 1H, Examples thereof include 5H-octafluoropentyl (meth) acrylate. These fluorine-containing (meth) acrylic monomers can be used in combination. Also, fluorine-containing polyfunctional (meth) acrylic monomers can be used.

  In addition, the dispersion comprising the ink of the present invention preferably has an average particle diameter of 50 nm or more and 300 nm or less that enables the organic pigment to be dispersed in water with the polymer. Moreover, it is preferable that the styrene conversion weight average molecular weight by gel permeation chromatography (GPC) of this polymer is 10,000 or more and 200,000 or less. When the weight average molecular weight in terms of styrene is 10,000 or more and 200,000 or less, fixability of a pigment as a textile ink is improved, and storage stability of the pigment ink is also improved. In addition to the polymer as a dispersant, a water-dispersible or water-soluble polymer or a surfactant may be added as a dispersion stabilizer in order to stabilize the dispersion. It is preferable that at least 80% or more of the polymer used for dispersing the pigment is a polymer obtained by copolymerization of (meth) acrylate and (meth) acrylic acid.

  The ink of the present invention preferably uses 1,2-alkylene glycol. By using 1,2-alkylene glycol, bleeding is reduced and print quality is improved. Examples of 1,2-alkylene glycols used in the present invention are 1, 5 or 6 carbon atoms such as 1,2-hexanediol, 1,2-pentanediol and 4-methyl-1,2-pentanediol, 2-alkylene glycol is preferred. Among them, 1,6-hexanediol and 4-methyl-1,2-pentanediol having 6 carbon atoms are preferable. The amount of these 1,2-alkylene glycols added is 0.3% to 30% by weight (hereinafter sometimes simply referred to as “%”), more preferably 0.5% to 10%.

  The ink of the present invention preferably uses glycol ether. As this glycol ether, it is preferable to use diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monobutyl ether and dipropylene glycol monobutyl ether. The addition amount of these glycol ethers is 0.1% to 20%, more preferably 0.5% to 10%.

  The ink of the present invention preferably uses an acetylene glycol surfactant and / or an acetylene alcohol surfactant. By using an acetylene glycol surfactant and / or an acetylene alcohol surfactant, bleeding is further reduced and printing quality is improved. The acetylene glycol surfactant and / or acetylene alcohol surfactant used in the present invention is 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetra. From alkylene oxide adducts of methyl-5-decyn-4,7-diol, 2,4-dimethyl-5-decyn-4-ol and alkylene oxide adducts of 2,4-dimethyl-5-decyn-4-ol One or more selected are preferred. These acetylene glycol surfactants and / or acetylene alcohol surfactants are available as Air Products (UK) Olfin 104 series, Nissin Chemical Industry Olfin E1010 and other E series, Surfinol 465 or Surfinol 61, etc. It is available. Addition of these improves the drying property of printing, and enables high-speed printing.

  The ink of the present invention uses two or more selected from the group consisting of the above 1,2-alkylene glycols, acetylene glycol surfactants and / or acetylene alcohol surfactants, and glycol ethers. As a result, bleeding can be further reduced. For example, a combination of 1,2-alkylene glycol and an acetylene glycol surfactant and / or acetylene alcohol surfactant, a combination of a glycol ether and an acetylene glycol surfactant and / or an acetylene alcohol surfactant Is mentioned.

  By preparing the ink for ink jet recording in this manner, the ink for ink jet recording excellent in color developing property, stability and fixability, and particularly excellent as the ink jet recording ink for textiles can be obtained.

  As the pigment that can be used in the present invention, carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black and the like are particularly preferable for black ink, but copper oxide, Metal pigments such as iron oxide (CI Pigment Black 11) and titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1) can also be used.

  Examples of pigments for color inks include C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55, 74, 81, 83 (Disazo Yellow HR), 93, 94, 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 128, 138, 153, 155, 180, 185, C.I. I. Pigment Red 1, 2, 3, 5, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 2 (Permanent Red 2B (Ba)), 48: 2 (Permanent Red 2B (Ca)), 48 : 3 (Permanent Red 2B (Sr)), 48: 4 (Permanent Red 2B (Mn)), 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81 (Rhodamine 6G rake), 83, 88, 101 (Bengara), 104, 105, 106, 108 (Cadmium red), 112, 114, 122 (Quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 202, 206, 09,219, C. I. Pigment violet 19, 23, C.I. I. Pigment orange 36, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 16, 17: 1, 56 , 60, 63, C.I. I. Pigment Green 1, 4, 7, 8, 10, 17, 18, 36, etc. can be used.

  The pigment used in the present invention is dispersed using a disperser. In that case, various commercially available dispersers can be used as the disperser, and non-media dispersion is preferable from the viewpoint of low contamination. . Specific examples thereof include a wet jet mill (Genus), a nanomer (Nanomer), a homogenizer (Gorin), an optimizer (Sugino Machine), and a microfluidizer (Microfluidics).

  Further, the amount of the pigment used for the ink jet recording ink of the present invention is preferably 0.5% to 30%, more preferably 1.0% to 15%. If the addition amount is less than this, the print density cannot be ensured, and if the addition amount is more than this, the viscosity of the ink increases or structural viscosity is generated in the viscosity characteristics, and the ejection stability of the ink from the ink jet head tends to deteriorate. .

  Further, the ink of the present invention has a humectant, a solubilizer, a penetration controller, and a viscosity modifier for the purpose of ensuring the standing stability, stable ejection from the ink jet head, improvement of clogging, or prevention of ink deterioration. Various additives such as a pH adjuster, a solubilizer, an antioxidant, an antiseptic, an antifungal agent, a corrosion inhibitor, and a chelate for capturing metal ions that affect the dispersion can also be added.

  In addition, the ink of the present invention is preferably ejected by a method using an electrostrictive element such as a piezo element that does not heat. When heating such as a thermal head occurs, the added polymer The polymer used for dispersing fine particles and pigments is likely to be deteriorated and discharge becomes unstable. In particular, when a large amount of ink is ejected over a long period of time, such as an inkjet ink for textiles, a heating head is not preferable.

  Hereinafter, the present invention will be described more specifically. Examples are shown using pigments dispersed using the most preferred polymer, but the present invention is not limited to these examples.

Example 1
(1) Production of Pigment Dispersion 1 Pigment Blue 15: 3 (copper phthalocyanine pigment: manufactured by Clariant) was used as the pigment dispersion 1. The reaction vessel equipped with a stirrer, thermometer, reflux tube and dropping funnel was purged with nitrogen, and then 65 parts of benzyl acrylate, 2 parts of acrylic acid, 10 parts of 2,2,2-trifluoroethyl acrylate, t-dodecyl mercaptan, 0. Add 3 parts and heat to 70 ° C., separately prepared 135 parts benzyl acrylate, 15 parts acrylic acid, 5 parts butyl acrylate, 15 parts 2,2,2-trifluoroethyl acrylate, 1 part t-dodecyl mercaptan, methyl ethyl ketone 20 parts and 1 part of sodium persulfate were placed in a dropping funnel and the dispersion polymer was subjected to a polymerization reaction while dropping into a reaction vessel over 4 hours. Next, methyl ethyl ketone was added to the reaction vessel to prepare a dispersed polymer solution having a concentration of 40%. When the solvent was measured as THF using gel permeation chromatography (GPC) of L7100 system manufactured by Hitachi, Ltd., the styrene-converted molecular weight of the dispersion polymer was 100,000.

  Further, 40 parts of the dispersion polymer solution, 30 parts of Pigment Blue 15: 3, 100 parts of a 0.1 mol / L sodium hydroxide aqueous solution, and 30 parts of methyl ethyl ketone were mixed. Then, using an ultra-high pressure homogenizer (Ultimizer HJP-25005 manufactured by Sugino Machine Co., Ltd.), it was dispersed by passing 15 passes at 200 MPa. Then, it moved to another container, 300 parts of ion-exchange water was added, and also it stirred for 1 hour. And the whole amount of methyl ethyl ketone and a part of water were distilled off using the rotary evaporator, and it neutralized with 0.1 mol / L sodium hydroxide, and adjusted to pH9. Then, it was filtered with a 0.3 μm membrane filter and adjusted with ion exchange water to obtain a pigment dispersion 1 having a pigment concentration of 15%. It was 80 nm when the particle size was measured using a Microtrac particle size distribution analyzer UPA250 (manufactured by Nikkiso).

(2) Preparation of inkjet recording ink Table 2 shows examples of compositions suitable for inkjet recording ink. The ink for inkjet recording of the present invention was prepared by using the pigment dispersion 1 prepared by the above method and mixing it with the vehicle components shown in Table 2. In addition, 0.05% of the top side 240 (manufactured by Permachem Asia Co., Ltd.) is used for the remaining amount of water in Examples and Comparative Examples of the present invention to prevent ink corrosion, and benzotriazole is used to prevent ink jet head member corrosion. 0.02%, and EDTA (ethylenediaminetetraacetic acid) .2Na salt in an amount of 0.04% was added to ion-exchanged water in order to reduce the influence of metal ions in the ink system.

(3) Abrasion resistance test and dry cleaning property test Using the ink of Example 1, a sample printed solid on cotton using PX-V630 manufactured by Seiko Epson Corporation as an inkjet printer is prepared. The sample was subjected to friction fastness by rubbing 100 times with a load of 200 g using a Gakushin type friction fastness tester AB-301S manufactured by Tester Sangyo Co., Ltd. Two levels of dry and wet were evaluated according to Japanese Industrial Standard (JIS) JIS L0849, which confirms the degree of ink peeling. Similarly, the dry cleaning test was evaluated by the method B of JIS L0860. Table 1 shows the results of the abrasion resistance test and the dry cleaning test.

(4) Measurement of ejection stability Using the ink of Example 1, using PX-V630 manufactured by Seiko Epson Corporation as an inkjet printer, characters written in Microsoft Word on XeroxP paper A4 size manufactured by Fuji Xerox Co., Ltd. at 35 ° C and 35% atmosphere Evaluation was performed by printing 100 pages at a rate of 4000 characters / page with a standard of size 11, MSP Gothic. AA when there is no printing disorder at all, A when there is printing disorder at A, B at 2 to 3 printing disorder B, C at 4 to 5 printing disorder, 6 or more printing disorder The results are shown in Table 1 as D.

(Example 2)
(1) Production of Pigment Dispersion 2 First, Pigment Dispersion 2 was prepared in the same manner as Pigment Dispersion 1 using Pigment Violet 19 (Quinacridone Pigment: Clariant), and was used as Pigment Dispersion 2. The particle diameter was measured by the same method as in Example 1. As a result, it was 90 nm.

(2) Preparation of Ink for Inkjet Recording The pigment dispersion 2 prepared by the above method was used and mixed with the vehicle components shown in Table 2 to prepare and evaluate in the same manner as in Example 1.

(3) Scratch resistance test and dry cleaning property test Using the ink of Example 2, a rub resistance test and a dry cleaning property test were performed by the same method and the same evaluation method as in Example 1. Table 1 shows the results of the abrasion resistance test and the dry cleaning test.

(4) Measurement of ejection stability Using the ink of Example 2, ejection stability was measured by the same method and the same evaluation method as in Example 1. Table 1 shows the measurement results of the discharge stability.

(Example 3)
(1) Production of Pigment Dispersion 3 First, Pigment Dispersion 3 was prepared in the same manner as Pigment Dispersion 1 using Pigment Yellow 14 (azo pigment: manufactured by Clariant). The particle diameter was measured by the method used in Example 1 to be 115 nm.

(2) Preparation of Ink for Inkjet Recording The pigment dispersion 3 prepared by the above method was used and mixed with the vehicle components shown in Table 2 to prepare and evaluate in the same manner as in Example 1.

(3) Scratch resistance test and dry cleaning test Using the ink of Example 3, a scratch resistance test and a dry cleaning test were performed by the same method and the same evaluation method as in Example 1. Table 1 shows the results of the abrasion resistance test and the dry cleaning test.

(4) Measurement of ejection stability Using the ink of Example 3, the ejection stability was measured by the same method and the same evaluation method as in Example 1. Table 1 shows the measurement results of the discharge stability.

(Comparative Example 1)
(1) Production of Pigment Dispersion 4 Pigment Blue 15: 3 (copper phthalocyanine pigment: manufactured by Clariant) was used as the pigment dispersion 4. The reaction vessel equipped with a stirrer, thermometer, reflux tube and dropping funnel was purged with nitrogen, and then 75 parts of benzyl acrylate, 2 parts of acrylic acid, and 0.3 part of t-dodecyl mercaptan were added and heated to 70 ° C. separately. Disperse polymer while adding 150 parts of benzyl acrylate, 15 parts of acrylic acid, 5 parts of butyl acrylate, 1 part of t-dodecyl mercaptan, 20 parts of methyl ethyl ketone and 1 part of sodium persulfate to the reaction vessel over 4 hours. Was subjected to a polymerization reaction. Next, methyl ethyl ketone was added to the reaction vessel to prepare a dispersed polymer solution having a concentration of 40%. The styrene conversion molecular weight of the dispersion polymer measured in the same manner as in Example 1 was 100,000. The dispersion polymer does not contain a fluorine-containing (meth) acrylic monomer.

  Further, 40 parts of the dispersion polymer solution, 30 parts of Pigment Blue 15: 3, 100 parts of a 0.1 mol / L sodium hydroxide aqueous solution, and 30 parts of methyl ethyl ketone were mixed. Then, using an ultra-high pressure homogenizer (Ultimizer HJP-25005 manufactured by Sugino Machine Co., Ltd.), it was dispersed by passing 15 passes at 200 MPa. Then, it moved to another container, 300 parts of ion-exchange water was added, and also it stirred for 1 hour. And the whole amount of methyl ethyl ketone and a part of water were distilled off using the rotary evaporator, and it neutralized with 0.1 mol / L sodium hydroxide, and adjusted to pH9. Thereafter, the mixture was filtered through a 0.3 μm membrane filter and adjusted with ion exchange water to obtain a pigment dispersion 4 having a pigment concentration of 15%. In this pigment dispersion 4, no fluorine-containing (meth) acrylic monomer was used in the dispersion polymer. The particle diameter was measured in the same manner as in Example 1 to be 80 nm.

(2) Preparation of Ink for Inkjet Recording The pigment dispersion 4 prepared by the above method was used and mixed with the vehicle components shown in Table 2 to prepare and evaluate in the same manner as in Example 1.

(3) Scratch resistance test and dry cleaning property test Using the ink of Comparative Example 1, a scratch resistance test and a dry cleaning property test were performed by the same method and the same evaluation method as in Example 1. Table 1 shows the results of the abrasion resistance test and the dry cleaning test.

(4) Measurement of ejection stability The ejection stability was measured by the same method and the same evaluation method as in Example 1 using the ink of Comparative Example 1. Table 1 shows the measurement results of the discharge stability.

(Comparative Example 2)
(1) Production of Pigment Dispersion 5 Pigment Violet 19 (quinacridone pigment: manufactured by Clariant) was used as the pigment dispersion 5. The reaction vessel equipped with a stirrer, thermometer, reflux tube and dropping funnel was replaced with nitrogen, and then 40 parts of styrene, 25 parts of polyethylene glycol 400 acrylate, 10 parts of benzyl acrylate, 2 parts of acrylic acid, 2,2,2-trifluoro 10 parts of ethyl acrylate and 0.3 part of t-dodecyl mercaptan are added and heated to 70 ° C., separately prepared 135 parts of styrene, 88 parts of polyethylene glycol 400 acrylate, 15 parts of acrylic acid, 5 parts of butyl acrylate, 2, 2, 27 parts of 2-trifluoroethyl acrylate, 1 part of t-dodecyl mercaptan, 20 parts of methyl ethyl ketone and 1 part of sodium persulfate were placed in a dropping funnel and the dispersion polymer was polymerized while being dropped into the reaction vessel over 4 hours. Next, methyl ethyl ketone was added to the reaction vessel to prepare a dispersed polymer solution having a concentration of 40%. The composition ratio of benzyl acrylate compounded in the dispersion polymer is 2.8%.

  Further, 40 parts of the dispersion polymer solution, 30 parts of Pigment Violet 19 (quinacridone pigment: Clariant), 100 parts of a 0.1 mol / L sodium hydroxide aqueous solution, and 30 parts of methyl ethyl ketone were mixed. Then, using an ultra-high pressure homogenizer (Ultimizer HJP-25005 manufactured by Sugino Machine Co., Ltd.), it was dispersed by passing 15 passes at 200 MPa. Then, it moved to another container, 300 parts of ion-exchange water was added, and also it stirred for 1 hour. And the whole amount of methyl ethyl ketone and a part of water were distilled off using the rotary evaporator, and it neutralized with 0.1 mol / L sodium hydroxide, and adjusted to pH9. Thereafter, it was filtered through a 0.3 μm membrane filter and adjusted with ion exchange water to obtain a pigment dispersion 5 having a pigment concentration of 15%. The particle diameter was measured by the same method as in Example 1 to be 105 nm.

(2) Preparation of Ink for Inkjet Recording The pigment dispersion 5 prepared by the above method was used and mixed with the vehicle components shown in Table 2 to prepare and evaluate in the same manner as in Example 1.

(3) Abrasion resistance test and dry cleaning property test Using the ink of Comparative Example 2, an abrasion resistance test and a dry cleaning property test were performed by the same method and the same evaluation method as in Example 1. Table 1 shows the results of the abrasion resistance test and the dry cleaning test.

(4) Measurement of ejection stability Using the ink of Comparative Example 2, the ejection stability was measured by the same method and the same evaluation method as in Example 1. Table 1 shows the measurement results of the discharge stability.

(Comparative Example 3)
In Comparative Example 3, ink was prepared and evaluated in the same manner as in Example 2 except that a dispersion having a pigment particle size of 350 nm was prepared in Example 2. The particle size was measured by the same method as in Example 1. A dispersion having a particle diameter of 350 nm was designated as pigment dispersion 2A. The ink composition is shown in Table 2. The rubbing resistance test, the dry cleaning test and the discharge stability test were performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 4)
In Comparative Example 4, an ink was prepared and evaluated in the same manner as in Example 3 except that Pigment Yellow 14 (azo pigment: manufactured by Clariant) was used and Pigment Dispersion 6 prepared in the same manner as Pigment Dispersion 4 was used. did. It was 115 nm when the particle size of the pigment dispersion 6 was measured by the same method as Example 1. The ink composition is shown in Table 2. The rubbing resistance test, the dry cleaning test and the discharge stability test were performed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 5)
In Comparative Example 5, an ink was prepared and evaluated in the same manner as in Example 3 except that a pigment dispersion having a particle size of 360 nm was prepared in Example 3. The particle size was measured by the same method as in Example 1. The dispersion having a particle size of 360 nm was designated as pigment dispersion 3A. The ink composition is shown in Table 2. The rubbing resistance test, the dry cleaning test and the discharge stability test were performed in the same manner as in Example 1. The results are shown in Table 1.

Claims (4)

  As a constituent component, water is added to the pigment using a polymer obtained by polymerizing 45% by weight or more of benzyl acrylate, 15% by weight or less of methacrylic acid and / or acrylic acid, and 5% by weight or more of a fluorine-containing (meth) acrylic monomer. An ink for ink-jet recording comprising a dispersion having an average particle diameter of 50 nm to 300 nm, which is dispersible in the ink.   The dispersion has an average particle diameter of 50 nm to 300 nm in which an organic pigment can be dispersed in water with a polymer, and the polymer has a styrene-converted weight average molecular weight of 10,000 to 200,000 by gel permeation chromatography (GPC). The ink for inkjet recording according to claim 1, wherein:   The ink for inkjet recording according to claim 1 or 2, comprising 1,2-alkylene glycol.   The ink for inkjet recording according to any one of claims 1 to 3, further comprising an acetylene glycol surfactant and / or an acetylene alcohol surfactant.