JP2009057502A - Inkjet recording ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording ink which is excellent in stability, highly develops a color on plain paper, has a high glossing property on glossy paper, and is excellent in ink-discharging stability from an inkjet head. <P>SOLUTION: The inkjet recording ink contains at least a coloring material and polyoxy propylene glyceryl ether and further contains one or more kinds selected from a 1,2-alkylene glycol, glycol ether and acetylene glycol based surfactant. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink for ink jet recording having excellent stability, high color development on plain paper, high gloss on glossy paper, and excellent ink ejection stability from an ink jet head.

  Inkjet recording is a method of recording characters and figures on the surface of a recording medium by ejecting ink as small droplets from fine nozzles. As an ink jet recording method, an electric signal is converted into a mechanical signal by using an electrostrictive element, and ink stored in the nozzle head portion is intermittently ejected to record characters and symbols on the surface of the recording medium. A method of recording characters and symbols on the surface of the recording medium, etc. by rapidly heating a part of the ink stored in the part and generating bubbles by rapidly heating a part very close to the ejection part. Has been put to practical use.

  The ink used for such ink-jet recording has no bleeding, good drying properties, can be printed uniformly on the surface of various recording media, color printing, etc. In color printing, characteristics such as that adjacent colors do not mix 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). There are also examples using 1,2-hexanediol, 1,2-octanediol, 2-methyl-2-propyl-1,3-propanediol, etc. (see Patent Document 7).

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 Japanese Patent Laid-Open No. 9-3371

  However, conventional water-based inks have insufficient print quality, and are often smeared when printed on plain paper such as PPC paper, and color density and color developability are also insufficient. In addition, the conventional dispersion is unstable, and if 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 for dispersing the pigment is likely to occur. There was a problem that storage stability was inferior. 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 its object is to provide excellent stability, high color on plain paper, high gloss on glossy paper, 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.

  The inkjet ink of the present invention is an inkjet recording ink containing at least a coloring material and polyoxypropylene diglyceryl ether, and is further selected from 1,2-alkylene glycol, glycol ether, and acetylene glycol surfactant. It is characterized by comprising more than seeds.

  In view of the fact that the present invention is required to have characteristics such as excellent stability, high color development on plain paper, high gloss on special paper, and excellent ejection stability of ink from an inkjet head. This is due to the result of earnest examination.

  The ink for ink jet recording of the present invention is an ink for ink jet recording containing at least a coloring material and polyoxypropylene diglyceryl ether, and further selected from 1,2-alkylene glycol, glycol ether and acetylene glycol surfactant. It is characterized by comprising 1 or more types.

  The amount of the polyoxypropylene diglyceryl ether added is preferably 0.1% by weight (hereinafter simply referred to as “%” unless otherwise specified) and 5.0% or less. If it is less than 0.1%, the color developability of plain paper is lowered, and the glossiness of glossy paper is also lowered. If it exceeds 5.0%, the discharge stability is deteriorated. Furthermore, it is preferable that propyleneoxy of the above-mentioned polyoxypropylene diglyceryl ether is 1-50 in average per molecule of diglycerin. When propyleneoxy is in the above range, the ejection stability of ink from the inkjet nozzle is improved, and the glossiness is improved even on dedicated paper. However, it is more preferable to use a substance having propyleneoxy of 9 or more and 30 or less per molecule of diglycerin. More preferably, a substance having propyleneoxy of 15 or more and 20 or less per molecule of diglycerin is used. Furthermore, polyoxyethylene polyoxypropylene diglyceryl ether can be used in the same manner as polyoxypropylene diglyceryl ether. Also in this case, it is preferable that propyleneoxy is 1 or more and 50 or less per molecule of diglycerin.

  This polyoxypropylene diglyceryl ether is commercially available, for example, as SC-P series of Sakamoto Pharmaceutical Co., Ltd.

  In the present invention, in addition to polyoxypropylene diglyceryl ether, print quality is improved by using at least one selected from 1,2-alkylene glycol, glycol ether, and acetylene glycol surfactant. Examples of 1,2-alkylene glycols are 1,2-alkylene glycols having 5 or 6 carbon atoms such as 1,2-hexanediol, 1,2-pentanediol and 4-methyl-1,2-pentanediol. Is preferred. Among these, 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%, more preferably 0.5% to 10%. Further, as the glycol ether, it is preferable to use one or more selected from 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 preferably 0.1% to 20%, more preferably 0.5% to 10%. Acetylene glycol surfactants are 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetramethyl-5-decyne-4,7-. One or more selected from alkylene oxide adducts of diols are preferred. Examples of the alkylene oxide include ethylene oxide and propylene oxide, and the addition amount is preferably 1 to 30 with respect to 1 mol of 2,4,7,9-tetramethyl-5-decyne-4,7-diol. More preferably, it is 1-10. These acetylene glycol surfactants are available as Air Products (UK) Olfin 104 series, Olfin E1010 and other E series, Nissin Chemical's Surfynol 465, and the like. These additions improve the dryness of printing, and even if printing is performed continuously, the previous printing portion is not transferred to the back surface of the next medium, so that high-speed printing is possible.

  Furthermore, in the present invention, in addition to polyoxypropylene diglyceryl ether, 1,2-alkylene glycol and acetylene glycol surfactant, and a combination of a plurality of glycol ether and acetylene glycol surfactant are used. , More blurring can be reduced. More preferably, in addition to polyoxypropylene diglyceryl ether, bleeding is further reduced by using three types of 1,2-alkylene glycol, glycol ether, and acetylene glycol surfactant in combination.

  In the present invention, when a pigment is used as the coloring material, the glass transition temperature of the polymer used for dispersing the pigment is preferably 50 ° C. or lower. When the temperature exceeds 50 ° C., the color developability on plain paper decreases and the gloss on glossy paper also decreases.

  In this way, by preparing the ink for ink jet recording as described above, an ink jet ink that has high color on plain paper, high gloss on special paper, and excellent ink ejection stability from the ink jet head. Can do.

  Color materials that can be used in the present invention include dyes and pigments. As the dye, a general dye that can be used for inkjet can be used. Examples include color dyes classified as oil-soluble dyes, basic dyes, etc. in addition to those classified as acid dyes, direct dyes, reactive dyes, vat dyes, disperse dyes, sulfur dyes or food dyes in the color index. An agent can also be used. In addition, as a pigment for black ink, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black and channel black, or copper oxide, iron oxide (CI pigment) Examples include black 11), metals such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1). However, carbon black is preferable because it has a relatively low density and does not easily settle in water.

  For color inks, 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, 129, 138, 150, 153, 180, 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.

  As described above, it is preferable to use various dyes and pigments as the color material, but more preferably, the color material is dispersed using a polymer, the polymer is infiltrated with a dye, or polymer fine particles are used. This is the case of coexistence with a polymer.

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

  The addition amount of the color material used in the ink for ink jet recording 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-jet pigment ink in the present invention is a moisturizer or dissolution aid for the purpose of ensuring its standing stability, stable ejection from the ink-jet head, for improving clogging, or for preventing ink deterioration. Various additives such as chelating agents for trapping metal ions that affect dispersion, penetration control agents, viscosity modifiers, pH adjusters, dissolution aids, antioxidants, antiseptics, antifungal agents, corrosion inhibitors, and dispersion agents Can also be added.

  Hereinafter, specific embodiments of the present invention will be described. Examples are shown using pigments dispersed using the most preferred polymer, but dyes can be used in the same manner, and the present invention is not limited to these examples.

(Example 1 to Example 4)
(1) Production of Pigment Dispersion 1 As the pigment dispersion 1, Monarch 880 manufactured by Cabot Corporation of the United States, which is carbon black (Pigment Black 7), was used. 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 dispersion polymer solution having a concentration of 40%. A portion of this polymer was taken out and dried, and then the glass transition temperature was measured by a differential operation calorimeter (EXSTAR6000DSC, manufactured by Seiko Denshi).

  Further, 40 parts of the dispersion polymer solution, 30 parts of Monarch 880 powder (manufactured by Cabot) as carbon black, 100 parts of a 0.1 mol / L aqueous sodium hydroxide 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%.

(2) Production of Pigment Dispersion 2 First, Pigment Dispersion 2 was prepared in the same manner as Pigment Dispersion 1 using Pigment Blue 15: 4 (copper phthalocyanine pigment: manufactured by Clariant).

(3) Production of Pigment Dispersion 3 First, Pigment Dispersion 3 was prepared in the same manner as Pigment Dispersion 1 using Pigment Violet 19 (Quinacridone Pigment: Clariant).

(4) Production of Pigment Dispersion 4 First, Pigment Dispersion 3 was prepared in the same manner as Pigment Dispersion 1 using Pigment Yellow 74 (Condensed Azo Pigment: Clariant).

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

(6) Evaluation of plain paper OD and glossy paper glossiness Xerox 4024 paper manufactured by US Xerox was used as plain paper, and PM photo paper manufactured by Seiko Epson Corporation was used as glossy paper. The printer used was an ink jet printer EM930C manufactured by Seiko Epson Corporation, and evaluation was performed using a sample printed in a printing mode of 720 dpi for plain paper and 1440 dpi for glossy paper. The OD was measured using GRETAG MACBETH SPECTROSCAN SPM-50 manufactured by GRETAG, USA. The glossiness was measured by measuring the specular glossiness of the recording surface at an incident angle of 60 degrees with a gloss checker IG-320 manufactured by Horiba, Ltd., and taking the average of 5 times for each recording paper. The media was printed with Seiko Epson Corporation PM photographic paper, and the printer was printed with Seiko Epson Corporation EM930C with 720 dpi. The results are shown in Table 1. Comparison between Example 1 to which polyoxypropylene diglyceryl ether (hereinafter referred to as DGPO) was added and whether or not DGPO and other additives were added at the same time as Examples 2 to 4 and Comparative Example 1 (Tables 3 to 6) An example is shown. Examples of DGPO include DGPO6 (6PO adduct of diglycerin), DGPO15 (15PO adduct of diglycerin) and DGPO30 (30PO adduct of diglycerin), DGP014-EO5 (14PO adduct of diglycerin, and EO5 adduct) ) Is used.

(7) Measurement of ejection stability Using PX-V600 manufactured by Seiko Epson Corporation as an inkjet printer, MSP Gothic, a standard for character size 11 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. AA when there is no printing disorder at all, A when there is printing disorder at two places, B when there is printing disorder at two or three places, C when there is printing disorder at four to five places, and six or more printing disorders. The results are shown in Table 1 with D as the result. Moreover, it shows about the example compared about the presence or absence of addition of DGPO and another additive simultaneously as Examples 2-4 and Comparative Example 1 (Tables 3-6).

(Examples 5 to 8)
(1) Production of Pigment Dispersion 5 The pigment dispersion 5 used was MA100 manufactured by Mitsubishi Chemical Industries, Ltd., which is carbon black (PBk7). The reaction vessel equipped with a stirrer, thermometer, reflux tube and dropping funnel was replaced with nitrogen, and then 45 parts of styrene, 30 parts of polyethylene glycol 400 acrylate, 10 parts of benzyl acrylate, 2 parts of acrylic acid, 0.3 part of t-dodecyl mercaptan And heated to 70 ° C., and separately prepared 150 parts of styrene, 100 parts of polyethylene glycol 400 acrylate, 15 parts of acrylic acid, 5 parts of butyl acrylate, 1 part of t-dodecyl mercaptan and 5 parts of sodium persulfate are placed in a dropping funnel. Then, the dispersion polymer was polymerized while being dropped into the reaction vessel over 4 hours. Next, water was added to the reaction vessel to prepare a dispersed polymer solution having a concentration of 40%. A part of this polymer was taken and dried, and then the glass transition temperature was measured by a differential operation calorimeter (EXSTAR6000DSC manufactured by Seiko Denshi), and it was 45 ° C.

  Further, 40 parts of the above dispersion polymer solution and 30 parts of MA100 which is carbon black and 100 parts of 0.1 mol / L sodium hydroxide aqueous solution are mixed and dispersed using an Eiger mill using zirconia beads for 2 hours. Then, it transfers to another container, 300 parts of ion-exchange water is added, and also it stirs for 1 hour. And it neutralizes with 0.1 mol / L sodium hydroxide and adjusts to pH9. Then, it filtered with a 0.3 micrometer membrane filter, and was set as the dispersion 5 whose solid content (dispersion polymer and carbon black) is 20%.

(2) Production of Pigment Dispersion 6 First, Dispersion 6 was prepared in the same manner as Dispersion 5 using Pigment Blue 15: 3 (copper phthalocyanine pigment: manufactured by Clariant).

(3) Production of Pigment Dispersion 7 First, Dispersion 7 was prepared in the same manner as Dispersion 5 using Pigment Red 122 (Dimethylquinacridone Pigment: Clariant).

(4) Production of Pigment Dispersion 8 First, Dispersion 8 was prepared in the same manner as Dispersion 5 using Pigment Yellow 180 (Diketopyrrolopyrrole Pigment: Clariant).

(5) Preparation of inkjet ink Table 8 shows examples of compositions suitable for inkjet recording ink. The ink for inkjet recording was prepared in the same manner as in Example 1.

(6) Evaluation of plain paper OD and glossy paper glossiness Evaluation of plain paper OD and glossy paper glossiness was carried out in the same manner as in Example 1. The results are shown in Table 7. Moreover, it shows about the example compared about the presence or absence of addition of DGPO and another additive simultaneously as Examples 5-8 and Comparative Example 2 (Tables 9-12).

(7) Measurement of ejection stability The ejection stability was measured in the same manner as in Example 1. The results are shown in Table 7. Moreover, it shows about the example compared about the presence or absence of addition of DGPO and another additive simultaneously as Examples 5-8 and Comparative Example 2 (Tables 9-12).

(Example 9 to Example 12)
(1) Preparation of Ink-Jet Ink with Changed Addition of DGPO Hereinafter, Examples 9 to 12 and Comparative Example 3 with respect to the case where the addition amount of DGPO is changed as Examples and Comparative Examples of compositions suitable for ink-jet recording inks. And 4 are shown in Tables 14-19. The ink for inkjet recording was prepared in the same manner as in Example 1.

(2) Evaluation of dispersion stability Dispersion stability was evaluated in the same manner as in Example 1. The results are shown in Table 13.

(3) Evaluation of plain paper OD and glossy paper glossiness Evaluation of plain paper OD and glossy paper glossiness was carried out in the same manner as in Example 1. The results are shown in Table 13.

(4) Measurement of ejection stability The ejection stability was measured in the same manner as in Example 1. The results are shown in Table 13.

Claims (4)

  An ink for ink jet recording containing at least a coloring material and polyoxypropylene diglyceryl ether, and further comprising at least one selected from 1,2-alkylene glycol, glycol ether and acetylene glycol surfactant. Ink for inkjet recording characterized.   The ink for inkjet recording according to claim 1, wherein the polyoxypropylene diglyceryl ether is added in an amount of 0.1 wt% to 5.0 wt%.   The ink for inkjet recording according to claim 1 or 2, wherein the propyleneoxy group of the polyoxypropylene diglyceryl ether has an average of 1 to 50 per molecule of diglycerin.   The ink for inkjet recording according to any one of claims 1 to 3, wherein the coloring material is a pigment, and a glass transition temperature of a polymer used for dispersing the pigment is 50 ° C or lower.