JP2008231131A - Ink for inkjet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink for inkjet, excellent in preservation stability and ejection stability, and having a high color developing property on ordinary paper and glossy paper, and a high glossiness on the glossy paper jointly. <P>SOLUTION: This ink for the inkjet contains water, a pigment coated with a multiple number of polymer layers and a compound expressed by formula (1). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an ink jet ink having excellent storage stability and ejection stability, and having both high fixability and abrasion resistance and high glossiness on glossy paper.

  Many conventional inks for ink jet recording use dyes as coloring materials, and those using pigments are beginning to spread. Ink using the pigment was dispersed using a method using a surfactant as a means for dispersing the pigment in water (see Patent Document 1) or a dispersion polymer having a hydrophobic part and a hydrophilic part. (See Patent Document 2) Further, a method of coating the surface of a pigment with a polymer has been studied, and as an example, a method using a phase inversion emulsification reaction or an acid precipitation method has been studied (see Patent Document 3).

JP-A-01-301760 Japanese Patent Publication No. 5-064724 Japanese Patent Laid-Open No. 10-140065

  However, in any case, since a polymer containing styrene as a main constituent is used as a method for dispersing the pigment, the fixability is not so much, and yellowing is easily caused by long-term storage of the printed matter. Further, in the normal case, when a substance having a hydrophilic part and a hydrophobic part such as a surfactant or glycol ether is present, there is a problem that adsorption / desorption tends to occur and storage stability is inferior. Conventional 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 paper permeability, and there is a problem in that the type of paper is limited in order to perform uniform printing, which tends to cause deterioration in print image quality.

  Further, for example, additives for improving the print quality (acetylene glycol, acetylene alcohol, silicon surfactant, di (tri) ethylene glycol monobutyl ether or 1,2-alkylene glycol or a mixture thereof) to the conventional dispersion Long-term storage stability cannot be obtained, and in the case of pigment inks, the re-solubility is poor, so that the ink dries and easily becomes clogged with the nozzles of the ink-jet head, and the adhesion used for the substances constituting the head However, the adhesive strength is reduced due to deterioration of the agent and the like, resulting in poor discharge stability.

  In addition, pigments dispersed with such a general dispersant remain in the ink system, resulting in low abrasion resistance, or the dispersant does not contribute sufficiently to disperse from the pigment. Therefore, there is a problem that the viscosity becomes high. When the viscosity is increased, the amount of the coloring material such as pigment is limited, and there is a problem that sufficient print quality cannot be obtained particularly on plain paper.

  The ink-jet ink of the present invention comprises water, at least a pigment coated with a plurality of polymer layers, and a compound of the formula (1).

  The ink-jet ink of the present invention is excellent in storage stability and ejection stability, and has an effect of providing an ink-jet ink having both high fixability and abrasion resistance and high glossiness on glossy paper.

  The inkjet ink of the present invention has excellent storage stability, high fixability and abrasion resistance, sufficient gloss on glossy paper, and excellent properties such as excellent ink ejection stability from an inkjet head. This is due to the result of earnest examination in view of the demand.

  The inkjet ink according to the present invention includes water, a pigment coated with a plurality of polymer layers, and a compound of the formula (1).

  Here, the “pigment coated with a plurality of polymer layers” refers to a polymer-coated pigment that has undergone a plurality of steps of coating the surface of the pigment with a polymer layer. As a result, the layer thickness of the polymer covering the pigment is increased, and the increase in the viscosity of the ink is suppressed, and the abrasion resistance and the fixing property are improved.

  If the adduct of alkyl alcohol polyoxypropylene and polyoxyethylene has less than 8 carbon atoms, the glossiness of glossy paper decreases. If it exceeds 18, the viscosity of the ink increases and ejection stability cannot be obtained.

  In the present invention, the compound of the formula (1) preferably has R as an alkanol group having 8 to 18 carbon atoms. When the number of carbon atoms is less than 8, glossiness on glossy paper is difficult to obtain. If it exceeds 18, in order to improve the solubility in water, it is necessary to add a large amount of ethyleneoxy. However, if this is done, foaming is likely to occur, and ink jet dot loss is likely to occur. Color developability also decreases. n is preferably 4 to 12, and if it is less than 4, glossiness on glossy paper is difficult to improve, and if it exceeds 12, a large amount of addition of ethyleneoxy is required to improve solubility in water. Foaming is likely to occur, and ink-jet dot loss is likely to occur, and color development on plain paper is also reduced. m is from 1 to 12, but if it is less than 1, the solubility in water decreases, so the amount added is limited and glossiness of glossy paper cannot be obtained. If it exceeds 12, foaming is likely to occur, and ink-jet dot loss is likely to occur, and in addition, the color developability on plain paper also decreases. The addition of propyleneoxy and ethyleneoxy to the alkyl group may be random or block, but the structure in which propyleneoxy is added to the alkyl group as a block and then ethyleneoxy is added as a block is random addition or alkylation. Glossiness on glossy paper is improved and color developability on plain paper is improved compared to adding ethyleneoxy in blocks and then adding ethyleneoxy in blocks.

  In this invention, what polymerized acrylic acid ester and (meth) acrylic acid as a structural component of a polymer is preferable. Furthermore, when methacrylic acid and acrylic acid are compared, it is more preferable from the viewpoint of fixability to use acrylic acid.

  Examples of pigments that can be used in the present invention include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, or copper oxides and iron oxides for black inks. (CI Pigment Black 11), metals such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1) are used. Hard carbon black is preferred.

  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, 138, 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, 209, 219, . 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 that can be used in the present invention is dispersed using a disperser. In this case, various commercially available dispersers can be used as the disperser, but non-media dispersion is preferable. Specific examples thereof include a wet jet mill (Genus), a nanomer (Nanomer), a homogenizer (Gorin), an optimizer (Sugino Machine), and a microfluidizer (Microfluidics).

  In the present invention, the addition amount as a pigment is preferably 0.5% to 30%, more preferably 1.0% to 12%. 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. .

  The polymer used for dispersion of the pigment in the present invention is a commercially available styrene- (meth) acrylic acid copolymer, styrene- (meth) acrylic acid- (meth) acrylic acid ester copolymer, polyethylene glycol ( It is also possible to use a combination of one or more selected from a (meth) acrylate- (meth) acrylic acid copolymer, a vinyl acetate-maleic acid copolymer, a styrene-maleic acid copolymer, and the like. However, at least 80% or more is preferably a polymer obtained by copolymerization of an acrylic ester and acrylic acid. The acrylic acid esters include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, cyclohexyl acrylate, octyl acrylate, lauryl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl carbitol acrylate, phenol EO-modified acrylate, N-vinyl. Commercial acrylic acid such as pyrrolidone, isobornyl acrylate, benzyl acrylate, dicyclopentenyl acrylate, dicyclopentanyl acrylate, dicyclopentenyloxyethyl acrylate, paracumylphenol EO modified acrylate, 2-hydroxyethyl-3-phenoxypropyl acrylate Esters can be used. Further, ω-carboxy-polycaprolactone monoacrylate, phthalic acid monohydroxyethyl acrylate, acrylic acid dimer or the like can be used instead of acrylic acid.

  Moreover, phase inversion emulsification can be used for the method of coating the pigment of the polymer of the present invention on a pigment. By using the phase inversion emulsification method, the ink becomes stable and the color developability of plain paper is improved. When the treatment for coating the polymer is performed a plurality of times, either batch treatment or continuous treatment can be employed.

  2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 2,4,7,9-tetramethyl-5 One or more selected from alkylene oxide adduct of decyne-4,7-diol and alkylene oxide adduct of 3,6-dimethyl-4-octyne-3,6-diol is plain paper at less than 0.05% by weight This is not preferable because of increased bleeding. On the other hand, if it exceeds 1% by weight, the storage stability as an ink-jet ink deteriorates and long-term storage becomes difficult. More preferably, it is 0.1 wt% or more and 0.7 wt%.

  2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 2,4,7,9-tetramethyl-5 The alkylene oxide adduct of decyne-4,7-diol is commercially available, Surfinol 104, Surfinol 82, Surfinol 2502, Surfinol 420, Surfinol 440, Surfinol 465, Surfinol 485, manufactured by Nissin Chemical Co., Ltd. It can be obtained as acetylenol EOO, acetylenol E40, acetylenol E100, etc. manufactured by Kawaken Fine Chemicals.

  In the present invention, it preferably comprises 1,2-alkylene glycol. Among the 1,2-alkylene glycols, 1,2-hexanediol and 4-methyl-1,2-pentanediol are particularly preferable. By using the pigment according to the present invention and further using these, the ejection stability of the inkjet ink can be improved. Improves bleeding when printing on plain paper.

  Further, it comprises at least one selected from di (tri) ethylene glycol monobutyl ether, (di) propylene glycol monobutyl ether, di (tri) ethylene glycol monopentyl ether and di (tri) ethylene glycol monohexyl ether. Is preferred. By using the pigment according to the present invention and further using these glycol ethers, the bleeding when printed on plain paper by the ink jet method is further reduced, and the printing quality is improved.

  Moreover, it is also preferable that 2-butyl-2-ethyl-1,3-propanediol is included, and the pigment according to the present invention is used, and 2-butyl-2-ethyl-1,3-propanediol is further used. This improves glossiness on glossy paper and improves color development on plain paper.

  Moreover, although the polymer in this invention has a carboxyl group, it is preferable to comprise triethanolamine and / or tripropanolamine as the counter ion. By using triethanolamine and / or tripropanolamine, clogging of the inkjet ink is less likely to occur even in a dry state.

  Further, similarly, in order to make it difficult to cause clogging of the ink jet, it is preferable to include one or more selected from glycerin, trimethylolethane, trimethylolpropane, tetrasaccharide, pentasaccharide and hexasaccharide.

  In the polymer polymerization method of the present invention, an alcohol solvent, a ketone solvent, an ether solvent, or a glycol ether solvent can be used as a solvent. However, since it is an aqueous pigment dispersion, it is necessary to be able to remove the above-mentioned solvent later. Therefore, the following can be used as such a solvent. Examples of the alcohol solvent include methanol, ethanol, isopropanol, 1-butanol, tertiary butanol, isobutanol, diacetone alcohol and the like. Examples of the ketone solvent include acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, and cyclohexanone. Examples of the ether solvent include dibutyl ether, tetrahydrofuran, dioxane and the like. Furthermore, examples of the glycol ethers include ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol diethyl ether, and butyl cellosolve.

  Moreover, as a radical polymerization initiator for polymerizing a polymer, t-butyl peroxy (2-ethylhexanoate), di-t-butyl peroxide, t-butyl peroxybenzoate, t-butyl peroxyoct Organic peroxides such as ate, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), dimethyl-2,2′-azobisbutyrate, 2, Azo compounds such as 2′-azobis (2-methylbutyronitrile), potassium persulfate, sodium persulfate, and the like can be used, but are not limited to these, and start other than the above as long as radical polymerization is possible. An agent can also be used. The amount of radical polymerization initiator used is preferably 0.01 mol% or more and 5 mol% or less with respect to the monomer used in the polymerization. The polymerization temperature is not particularly limited, but is usually in the range of 30 ° C to 100 ° C, and preferably in the range of 40 ° C to 90 ° C. When the polymerization temperature is too low, it takes a long time to polymerize the monomer, and in some cases, the polymerization rate may decrease and a large amount of monomer may remain.

  In the present invention, a dispersant, a surface tension adjusting agent or a penetrating agent (surfactant), a wetting and drying preventing agent, an antiseptic, a bactericidal agent, a pH adjusting agent, a rust preventing agent, a moisturizing agent and other additives are added as necessary. An agent may be used. These may be used alone or in combination of two or more.

  Next, as a method for producing the inkjet ink of the present invention, for example, the polymer composition for inkjet ink of the present invention, an aqueous medium, an alkali such as sodium hydroxide is emulsified by high-speed stirring, and a pigment or the like is further added. And a method of strongly dispersing with a disper or the like. Further, if necessary, a method of dispersing with a three-roll mill or the like, dispersing the obtained pigment slurry to a predetermined particle size with a high-pressure disperser or the like, and then removing the organic solvent or the like from the obtained pigment dispersion Etc. may be performed.

  The above-mentioned high-pressure disperser is not particularly limited, and examples thereof include a microfluidizer (Microfluidics), an optimizer (Sugino Machine), a wet jet mill (Genus), and a nanomizer (SG Engineering). It is done.

  The pressure at the time of dispersing with the above-described high-pressure disperser may be any as long as it can reach the desired pigment particle diameter, but is preferably 100 MPa to 300 MPa. If it is less than 100 MPa, the dispersed particle size tends to be large, and it takes a long time for dispersion, or unless the number of passes is extremely increased, it is difficult to form a stable dispersion and is not economical. Moreover, when it exceeds 300 MPa, it is easy to become overdispersed, and it is difficult to obtain the stability of the dispersion. If the desired pigment particle diameter cannot be reached, the dispersion may be carried out by increasing the number of dispersions or increasing the pressure within the aforementioned pressure range.

  In addition, in the method for producing an ink-jet ink of the present invention, an alkali solution is added to the above-described polymer composition for ink-jet ink that has been polymerized and heated, and then the solvent is removed and replaced with ion-exchanged water or the like. You may use the polymer composition solution for inkjet inks.

  Further, the solvent for the above-described ink-jet ink polymer that has been polymerized is removed by distillation under reduced pressure, the solid matter of the obtained ink-jet ink polymer is crushed, and ion-exchanged water, an alkali solution, etc. are added and dissolved by heating, You may use the polymer solution for inkjet inks obtained. In this case, thereafter, it is not necessary to remove the organic solvent and the like from the obtained pigment dispersion.

  Examples of the alkali used in the alkali solution include tertiary alkanolamines such as triethanolamine and tripropanolamine, alkylalkanolamines, inorganic bases such as sodium hydroxide, potassium hydroxide, and lithium hydroxide. It is done.

(Example)
The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples, and various modifications can be made without departing from the gist of the present invention.

  900.0 parts by weight of water and 500.0 parts by weight of Monarch 800 (CI PBk7: manufactured by Cabot) were mixed, and the Eiger Motor Mill M250 (manufactured by Eiger Japan) had a bead filling ratio of 70% and a rotation speed of 5000 rpm Dispersed under conditions for 2 hours. To this dispersion, 1500.0 parts by weight of sodium hypochlorite (effective chlorine concentration: 12%) was added dropwise and reacted for 5 hours while stirring with an Eiger motor mill, then the temperature was controlled at 100 ° C. and stirred for 8 hours. . Subsequently, the obtained slurry was filtered, washed with water, and adjusted to a carbon black pigment concentration of 50% to obtain a surface-treated carbon black slurry “B1”.

  Next, the inside of a 2000 ml separable flask equipped with a stirrer, a reflux tube, a thermometer, and a dropping funnel was purged with nitrogen, and then 200.0 parts by weight of diethylene glycol monomethyl ether was placed in the separable flask and heated to 80 ° C. while stirring. Warm up. Next, 200.0 parts by weight of diethylene glycol monomethyl ether, 303.0 parts by weight of benzyl acrylate, 130.0 parts by weight of 2-ethylhexyl acrylate, 100.4 parts by weight of acrylic acid and t-butylperoxy (2-ethylhexayl) were added to the dropping funnel. Noate) 4.8 parts by weight were added and reacted dropwise at 80 ° C. over 4 hours in a separable flask. After completion of dropping, the mixture was kept at 80 ° C. for 1 hour, 0.8 parts by weight of t-butylperoxy (2-ethylhexanoate) was added, and the reaction was further carried out at 80 ° C. for 1 hour. Thereafter, diethylene glycol monomethyl ether was removed by distillation under reduced pressure, and a polymer composition “P1” was obtained as the remaining resin solids.

  Next, the inside of a 2000 ml separable flask equipped with a stirrer, a reflux tube, a thermometer, and a dropping funnel was purged with nitrogen, and then 200.0 parts by weight of diethylene glycol monomethyl ether was placed in the separable flask and heated to 80 ° C. while stirring. Warm up. Thereafter, 200.0 parts by weight of diethylene glycol monomethyl ether, 483.0 parts by weight of benzyl acrylate, 50.4 parts by weight of acrylic acid, and 4.8 parts by weight of t-butylperoxy (2-ethylhexanoate) were placed in the dropping funnel. The reaction was conducted dropwise at 80 ° C. over 4 hours in a separable flask. After completion of dropping, the mixture was kept at 80 ° C. for 1 hour, 0.8 parts by weight of t-butylperoxy (2-ethylhexanoate) was added, and the reaction was further carried out at 80 ° C. for 1 hour. Thereafter, diethylene glycol monomethyl ether was removed by distillation under reduced pressure. Then, 600.0 parts by weight of methyl ethyl ketone was added to obtain a polymer composition solution “P2” having a resin solid content of 50%.

  Next, 60.0 parts by weight of the polymer composition “P1” was added to 960.0 parts by weight of the carbon black slurry “B1” and stirred for 5 minutes with a high-speed disper to obtain a pigment dispersion slurry. After adding 600.0 parts by weight of methyl ethyl ketone and stirring with a high-speed disperser for 1 hour, carbon black was repeatedly dispersed 10 times at a pressure of 200 MPa with an ultra-high pressure homogenizer (Microfluidizer: manufactured by Mizuho Kogyo Co., Ltd.). Dispersion “C1” was obtained.

  Next, 3.0 parts by weight of a 30% aqueous sodium hydroxide solution is added to 120.0 parts by weight of the polymer composition solution “P2”, and the mixture is stirred for 5 minutes with a high-speed disper, and further the carbon black dispersion “C1” 1500.0 parts by weight was added and stirred with a high speed disper for 1 hour. Then, it was continuously dispersed 10 times at a pressure of 200 MPa with an ultrahigh pressure homogenizer to obtain a pigment dispersion.

  Further, methyl ethyl ketone and a part of water were distilled off from the pigment dispersion thus obtained by vacuum distillation using an evaporator, and centrifuged at 5000 rpm for 30 minutes with a centrifuge (05P-21, manufactured by Hitachi, Ltd.). After the separation, ion-exchanged water was added so that the solid content concentration was 15% by weight to prepare the carbon black dispersion 1. And it pressure-filtered using the 2.5 micrometer membrane filter (made by Advantech). Thereafter, ink jet inks having the ink composition 1 shown in Table 2 were prepared. In the compound of the formula (1), R is a nonanol group, n is 6, m is 5, and block addition in the order of PO-EO is used.

  The inside of a 2000 ml separable flask equipped with a stirrer, a reflux tube, a thermometer, and a dropping funnel was purged with nitrogen, and then 200.0 parts by weight of diethylene glycol monomethyl ether was placed in the separable flask and heated to 80 ° C. while stirring. . Thereafter, 200.0 parts by weight of diethylene glycol monomethyl ether, 483.0 parts by weight of benzyl acrylate, 50.4 parts by weight of methyl acrylate, and 4.8 parts by weight of t-butylperoxy (2-ethylhexanoate) were placed in the dropping funnel. The reaction was conducted dropwise at 80 ° C. over 4 hours in a separable flask. After completion of dropping, the mixture was kept at 80 ° C. for 1 hour, 0.8 parts by weight of t-butylperoxy (2-ethylhexanoate) was added, and the reaction was further carried out at 80 ° C. for 1 hour. Thereafter, diethylene glycol monomethyl ether was removed by distillation under reduced pressure. Then, 600.0 parts by weight of methyl ethyl ketone was added to obtain a polymer composition solution “P3” having a resin solid content of 50%. 480.0 parts by weight of Monarch 800 (CI PBk7: manufactured by Cabot Corp.) was added to 120.0 parts by weight of this polymer composition solution “P3”, and the mixture was stirred for 1 hour with a high-speed disper to obtain a carbon black dispersion “C2 "

  Next, a polymer composition solution “P2” was produced in the same manner as in Example 1. To 120.0 parts by weight of the polymer composition solution “P2”, 3.0 parts by weight of a 30% aqueous sodium hydroxide solution is added and stirred for 5 minutes with a high-speed disper. Further, the carbon black dispersion “C2” 600 0.0 part by weight was added and the mixture was stirred with a high-speed disper for 1 hour. And this was continuously dispersed 10 times at a pressure of 200 MPa by an ultrahigh pressure homogenizer (Microfluidizer, manufactured by Mizuho Kogyo Co., Ltd.) to obtain a pigment dispersion.

  Further, methyl ethyl ketone and a part of water were distilled off from the pigment dispersion thus obtained by vacuum distillation using an evaporator, and centrifuged at 5000 rpm for 30 minutes with a centrifuge (05P-21, manufactured by Hitachi, Ltd.). After the separation, ion-exchanged water was added to adjust the carbon black dispersion 2 so that the solid content concentration was 15% by weight. And it pressure-filtered using the 2.5 micrometer membrane filter (made by Advantech). Thereafter, an ink jet ink having an ink composition 2 shown in Table 2 was prepared. The same compound as in Example 1 was used as the compound of formula (1).

(Comparative Example 1)
A polymer composition solution “P2” was prepared in the same manner as in Example 1. To 120.0 parts by weight of this polymer composition solution “P2”, 3.0 parts by weight of a 30% aqueous sodium hydroxide solution was added and stirred for 5 minutes with a high-speed disper, and Monarch 800 (CI PBk7: 480.0 parts by weight of Cabot Corporation) was added, and the mixture was stirred with a high-speed disper for 1 hour. And this was continuously disperse | distributed 10 times by the pressure of 200 Mpa by the ultrahigh pressure homogenizer (microfluidizer, Mizuho Kogyo Co., Ltd.), and the pigment dispersion liquid was obtained.

  Further, methyl ethyl ketone and a part of water were distilled off from the pigment dispersion thus obtained by vacuum distillation using an evaporator, and centrifuged at 5000 rpm for 30 minutes with a centrifuge (05P-21, manufactured by Hitachi, Ltd.). After the separation, ion-exchanged water was added so that the solid concentration was 15% by weight to prepare the carbon black dispersion 3. And it pressure-filtered using the 2.5 micrometer membrane filter (made by Advantech). Thereafter, an ink jet ink having an ink composition 3 shown in Table 2 was prepared. The same compound as in Example 1 was used as the compound of formula (1).

(Comparative Example 2)
A polymer composition solution “P2” was prepared in the same manner as in Example 1. To 240.0 parts by weight of this polymer composition solution “P2”, 5.0 parts by weight of a 30% aqueous sodium hydroxide solution is added and stirred for 5 minutes with a high-speed disper, and Monarch 800 (C.I. PBk7: 480.0 parts by weight of Cabot Corporation) was added, and the mixture was stirred with a high-speed disper for 1 hour. And this was continuously dispersed 10 times at a pressure of 200 MPa by an ultrahigh pressure homogenizer (Microfluidizer, manufactured by Mizuho Kogyo Co., Ltd.) to obtain a pigment dispersion.

  Further, methyl ethyl ketone and a part of water were distilled off from the pigment dispersion thus obtained by vacuum distillation using an evaporator, and centrifuged at 5000 rpm for 30 minutes with a centrifuge (05P-21, manufactured by Hitachi, Ltd.). After the separation, ion-exchanged water was added to adjust the carbon black dispersion 4 so that the solid content concentration was 15% by weight. And it pressure-filtered using the 2.5 micrometer membrane filter (made by Advantech). Thereafter, an ink jet ink having an ink composition 4 shown in Table 2 was prepared. The same compound as in Example 1 was used as the compound of formula (1).

(Evaluation Test 1: Evaluation Method for Colorability of Plain Paper)
Using the inkjet printer (EM-930C, manufactured by Seiko Epson Corporation), the inkjet inks according to Examples 1-2 and Comparative Examples 1-2 were solid-printed on XeroxP paper (produced by Fuji Xerox Co., Ltd.) to obtain a test specimen. It was. The print mode was paper: plain paper, print quality: super fine, color correction: none, print direction: bidirectional. And the OD value of each color was measured using GRETAGMACBETH SPECTROSCANSP50 (made by Gretag (USA)). The results are shown in Table 1 as OD values.

(Evaluation Test 2: Glossiness Evaluation Method)
The inkjet ink according to Examples 1-2 and Comparative Examples 1-2 was solid-printed on PM photographic paper (Seiko Epson) with an inkjet printer (EM-930C, Seiko Epson) to obtain a test specimen. The print mode was paper: photo print paper, print quality: photo, color correction: none, print direction: bidirectional. The 20 degree gloss of this test specimen was measured with a gloss meter (HG-268, manufactured by Suga Test Instruments Co., Ltd.). The results are shown in Table 1.

(Evaluation Test 3: Evaluation Method for Fixability)
The inkjet ink according to Examples 1-2 and Comparative Examples 1-2 was solid-printed in a 10 mm × 10 mm area on PM photographic paper (Seiko Epson) with an inkjet printer (EM-930C, manufactured by Seiko Epson). The print mode was paper: photo print paper, print quality: photo, color correction: none, print direction: bidirectional. Thereafter, it was left at a temperature of 25 ° C. for 6 hours. Scotch mending tape (manufactured by Sumitomo 3M) 18 mm width type is affixed lightly so as to completely cover the printing area of the obtained specimen, and a cylindrical metal roller having a diameter of 20 mm and a weight of 200 g is placed thereon. On top of this, this was rolled and the tape application part was reciprocated four times. Next, the attached tape was peeled off, and the degree of peeling was visually observed and evaluated according to the following criteria. The results are shown in Table 1.
A: No peeling occurs.
B: The area where peeling occurred is less than 10% with respect to the total area of the printing region.
C: The area where peeling occurred was 10% or more with respect to the total area of the printing region.

(Evaluation Test 4: Evaluation Method for Abrasion Resistance)
The inkjet ink according to Examples 1-2 and Comparative Examples 1-2 was solid-printed in a 10 mm × 10 mm area on PM photographic paper (Seiko Epson) with an inkjet printer (EM-930C, manufactured by Seiko Epson). The print mode was paper: photo print paper, print quality: photo, color correction: none, print direction: bidirectional. Then, it was left at a temperature of 25 ° C. for 1 hour. The printed area of the obtained test specimen was rubbed at a speed of 10 mm / second with a load of 250 g using a yellow aqueous fluorescent pen (ZEBRA PEN2: manufactured by Zebra). The degree of contamination at the rubbed area was observed and evaluated according to the following criteria. The results are shown in Table 1.
A: Dirt is not generated at all by rubbing twice.
B: Dirt is not generated by rubbing once, but dirt is generated by rubbing twice.
C: Dirt is generated by rubbing once.

In addition, the symbol shown in Table 1 and Table 2 is as follows.
TEGmBE: triethylene glycol monobutyl ether BEPD: 2-butyl-2-ethyl-1,3-propanediol 1,2-HD: 1, 2-hexanediol TMP: trimethylolpropane

  In Table 2, the compounding ratio of each component is shown by weight%. In the formula (1), R represents the number of carbon atoms of the alkyl group, n represents the number of moles of propyleneoxyPO added, and m represents the number of moles of ethyleneoxyEO added. The formula (1) is added in the order of addition of propyleneoxy PO to the alkyl group R as R-POEO, and that in which ethyleneoxy EO is added to the alkyl group R as R-EOPO. ) The addition form indicates whether propyleneoxy PO and ethyleneoxy EO are added to the alkyl group R in a block manner or randomly.

  As can be seen from the results in Table 1, when the inkjet inks according to Examples 1 and 2 were used, any of the evaluation tests 1 to 4 gave good results, but the inkjet inks according to Comparative Examples 1 and 2 were used. In such a case, any of the evaluation tests 1 to 4 or a plurality of items do not give a good result.

Claims (5)

An ink-jet ink comprising water, a pigment coated with a plurality of polymer layers, and a compound of formula (1).

  0.05% to 1% by weight of 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetramethyl-5-decyne-4,7 The inkjet ink according to claim 1, comprising at least one selected from alkylene oxide adducts of diols.   The inkjet ink according to claim 1, comprising 1,2-alkylene glycol.   The inkjet ink according to any one of claims 1 to 3, comprising at least one selected from di (tri) ethylene glycol monobutyl ether and (di) propylene glycol monobutyl ether.   The inkjet ink according to claim 1, comprising 2-butyl-2-ethyl-1,3-propanediol.