JP2007099916A - Inkjet recording ink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording ink that is excellent in preservation stability and jetting stability and satisfies both high color developability on a plain paper and a glossy paper and high gloss on a glossy paper. <P>SOLUTION: The inkjet recording ink comprises water and a pigment dispersion obtained by modifying the surface of a self-dispersible pigment particle with a polymer composition comprising a polymer that is obtained by polymerizing at least, as constituents thereof, 50 wt.% or more of benzyl acrylate and not more than 15 wt.% of (meth)acrylic acid and has an acid value of 50 mg KOH/g or more and not more than 120 mg KOH/g and a weight-average molecular weight of 20,000 or more and not more than 120,000. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink for ink jet recording which is excellent in storage stability and ejection stability, and has both high colorability on plain paper and glossy paper and high glossiness on glossy paper.

  Conventional inks for ink jet recording have often used dyes as coloring materials, but in recent years, inks using pigments have become widespread. In an ink using a pigment, a method using a surfactant as a means for dispersing the pigment in water (see Patent Document 1), a method using a dispersion polymer having a hydrophobic part and a hydrophilic part (see Patent Document 2), Alternatively, a method of coating the surface of the pigment with a polymer has been studied, and examples thereof include a phase inversion emulsification reaction and an acid precipitation method (see Patent Document 3). Further, there is a method of imparting dispersibility by a method of chemically modifying the pigment surface with a hydrophilic functional group (see Patent Document 4).

Japanese Patent Laid-Open No. 01-301760 Japanese Patent Laid-Open No. 06-306317 Japanese Patent Laid-Open No. 10-140065 JP 2002-322394 A

  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 permeability to paper, and there is a problem that the type of paper is limited in order to perform uniform printing, which tends to cause a reduction in the printed image.

  Further, for example, additives for improving printing quality (acetylene glycol surfactants, acetylene alcohol surfactants, silicon surfactants, di (tri) ethylene glycol monobutyl ether, or 1,2) are added to conventional dispersions. -Alkylene glycol or a mixture thereof), long-term storage stability cannot be obtained, and in the case of pigment ink, the re-dissolvability is poor, so that the ink is dried and easily clogged with the nozzles of the inkjet head, However, there is a problem that a material such as an adhesive used for the substance constituting the material is attacked to lower the adhesive strength and deteriorate the ejection stability.

  In addition, the pigment dispersed by such a general dispersing agent has a residual dispersant remaining in the ink system, and the dispersing agent does not contribute sufficiently to the dispersion and becomes detached from the pigment and has a high viscosity. There was a problem of ending up. 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. On the other hand, the dispersion ink obtained by the hydrophilic treatment on the pigment surface can suppress the viscosity in the system as much as the addition of an excessive dispersant is suppressed, but it is difficult to obtain sufficient fixability on the recording surface.

  The ink for inkjet recording of the present invention is obtained by polymerizing water, at least 50% by weight of benzyl acrylate and 15% by weight or less of (meth) acrylic acid as a polymer component, and an acid of 50 mgKOH / g or more and 120 mgKOH / g or less. And a pigment dispersion obtained by modifying a self-dispersing pigment particle surface with a polymer composition having a valence and a weight average molecular weight of 20000 to 120,000.

  The ink for ink jet recording of the present invention is excellent in storage stability and ejection stability, and provides an ink for ink jet recording having both high color developability on plain paper and glossy paper and high gloss on glossy paper. Have

  The ink for ink-jet recording of the present invention is excellent in storage stability and ejection stability, has high color development on plain paper and glossy paper, has fixing properties in addition to sufficient gloss on glossy paper, This is due to the result of intensive studies in view of the demand for characteristics such as excellent ink ejection stability.

  The ink for inkjet recording of the present invention is obtained by polymerizing water, at least 50% by weight of benzyl acrylate and 15% by weight or less of (meth) acrylic acid as a polymer component, and an acid of 50 mgKOH / g or more and 120 mgKOH / g or less. And a pigment dispersion obtained by modifying a self-dispersing pigment particle surface with a polymer composition having a valence and a weight average molecular weight of 20000 to 120,000.

  In the present invention, a polymer in which 50% by weight or more of benzyl acrylate and 15% by weight or less of (meth) acrylic acid are polymerized is preferable. However, when benzyl acrylate is less than 50% by weight, the fixing property is lowered. Therefore, the preferable range is 50% by weight or more, but the case of less than 50% by weight is not denied. Therefore, it is preferably 50% by weight or more, more preferably 60% by weight or more, and still more preferably 70% by weight or more. Polymerization with 15% by weight or less of (meth) acrylic acid is preferable. However, if it exceeds 15% by weight, the color developability of the inkjet ink on plain paper tends to decrease, but polymerization exceeding 15% by weight is likely to occur. A more preferable range is not more than 10% by weight. When methacrylic acid and acrylic acid are compared, it is more preferable to use acrylic acid from the viewpoint of fixability.

  The pigment used in the present invention is, for example, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, copper oxide, iron oxide (C CI pigment black 11), metals such as titanium oxide, and organic pigments such as aniline black (CI pigment black 1), but carbon black has a relatively low specific gravity and is difficult to settle in water for inkjet use. Is preferred. Further, for color use, 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, 209, 219, 254, . I. Pigment violet 19, 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.

  In the present invention, the addition amount of the pigment is preferably 0.5 to 30% by weight, more preferably 1.0 to 12% by weight. If the addition amount is 0.5% by weight or less, the print density cannot be secured, and if the addition amount is 30% by weight or more, the viscosity of the ink increases and structural viscosity is generated in the viscosity characteristics, and the ejection stability of the ink from the inkjet head Tends to get worse.

  Examples of the pigment of the ink for inkjet recording of the present invention include C.I. I. Black 7, C.I. I. Pigment blue 15: 1, 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 15: 6, C.I. I. Pigment green 36, C.I. I. Pigment red 122, C.I. I. Pigment red 177, C.I. I. Pigment red 254, C.I. I. Pigment violet 19, C.I. I. In the case of pigments other than yellow, such as CI Pigment Violet 23, the dispersion is performed using a polymer having an average particle size of 90 nm or less and an acid value of 50 mgKOH / g or more and 80 mgKOH / g or less. This is preferable from the viewpoint of providing an ink for ink jet recording which has excellent properties and has both high color development on plain paper and glossy paper and high gloss on glossy paper. When the average particle size exceeds 90 nm, the gloss on glossy paper decreases. Moreover, dispersion becomes unstable when the acid value is less than 50 mgKOH / g. Furthermore, when the acid value exceeds 80 mgKOH / g, the color developability on plain paper decreases. A more preferable acid value is 50 mgKOH / g to 70 mgKOH / g.

  Further, the pigment of the ink for ink jet recording of the present invention is, for example, C.I. I. Pigment yellow 55, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 79, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 110, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 138C. I. Pigment yellow 139, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 156, C.I. I. Pigment yellow 175 and C.I. I. In the case of a yellow pigment such as CI Pigment Yellow 180, it is possible to preserve the storage stability by using a polymer having an average particle size of 20 nm to 110 nm and an acid value of 50 mgKOH / g to 120 mgKOH / g. This is preferable from the viewpoint of providing an ink for ink jet recording which has excellent properties and ejection stability, and has both high color developability on plain paper and glossy paper and high gloss on glossy paper. When the average particle size is less than 20 nm, the light resistance deteriorates. When the average particle size exceeds 110 nm, the color developability on plain paper decreases. Further, when the acid value is less than 50 mgKOH / g, the dispersion becomes unstable, and when the acid value exceeds 120 mgKOH / g, the color developability on plain paper decreases.

  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 ( 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 can also be used. However, it is preferable that at least 80% or more is a polymer obtained by copolymerization of acrylate and acrylic acid. Examples of the acrylate 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 pyrrolidone, Commercially available acrylates such as isobornyl acrylate, benzyl acrylate, paracumylphenol EO-modified acrylate, and 2-hydroxyethyl-3-phenoxypropyl acrylate 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.

  Further, the dispersion method using the polymer used in the present invention uses a phase inversion emulsification method in which the pigment is modified so that the polymer is covered, whereby the ink becomes stable and the color developability of plain paper is improved.

  Furthermore, since the pigment particles to be modified are surface-treated and are in a dispersed form in the dispersion medium, the chance of contact between the pigment particle surface and the modified polymer is further increased. Therefore, phase inversion emulsification can be carried out quickly and efficiently as compared with the case of performing phase inversion emulsification treatment on pigment particles that are not so, and the coating uniformity on the surface can be improved. In addition, the viscosity is slightly increased by the amount of polymer coating by phase inversion emulsification compared to the dispersion of the surface-treated pigment alone, but the viscosity tendency is almost the same as the dispersion by phase inversion emulsification to other pigment particles. Indicates.

  In addition, the ink of the present invention has 2, 4, 7, 9-tetramethyl-5-decyne-4, 7-diol, 3,6-dimethyl-4-octyne-3, 6-diol, 2, 4, 7 , 9-tetramethyl-5-decyne-4,7-diol alkylene oxide adduct and 3,6-dimethyl-4-octyne-3, 6-diol alkylene oxide adduct It is preferable. These addition amounts are preferably 0.05% by weight or more and 1% by weight or less. If it is less than 0.05% by weight, bleeding on plain paper increases, which is not preferable. 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 -An alkylene oxide adduct of decyne-4,7-diol is commercially available, Surfinol 104, Surfinol 82, Surfinol 2502, Surfinol 420, Surfinol 440, Surfinol 465, Surfinol manufactured by Nissin Chemical Co., Ltd. 485, acetylenol EOO, acetylenol E40, acetylenol E100 manufactured by Kawaken Fine Chemical Co., Ltd. and the like.

  The ink of the present invention preferably contains 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 dispersion of the present invention and further using these, the ejection stability of the ink jet ink is used. And the bleeding when printed on plain paper is reduced.

  The ink of the present invention is one kind 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. It is preferable to comprise the above. By using the pigment dispersion of the present invention and further using these glycol ethers, bleeding when printed on plain paper by the inkjet method is further reduced, and the printing quality is improved.

  Further, the ink of the present invention preferably contains 2-butyl-2-ethyl-1,3-propanediol, and the pigment dispersion of the present invention is used to make 2-butyl-2-ethyl-1,3 -Further use of propanediol improves glossiness on glossy paper and improves color developability on plain paper.

  Moreover, although the polymer in this invention has a carboxyl group, it is preferable to contain 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.

  Similarly, the ink preferably contains at least one selected from glycerin, trimethylolethane, trimethylolpropane, tetrasaccharide, pentasaccharide, and hexasaccharide in order to make it difficult for inkjet clogging to occur. .

  Further, the polymer in which the pigment of the present invention is dispersed preferably has a weight average molecular weight of 20,000 or more and 200,000 or less. If the weight average molecular weight is less than 20,000, the long-term storage stability, thermal stability and fixability as an ink-jet ink will deteriorate, and if it exceeds 200,000, the viscosity as an ink-jet ink will increase and the dispersion stability will tend to deteriorate. There is also a tendency for the discharge stability to decrease.

  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 to 100 ° C, and preferably in the range of 40 to 90 ° C. When the polymerization temperature is too low, it is necessary to take a long time for the polymerization of the monomer, and in some cases, the polymerization rate may decrease and a large amount of monomer may remain.

  In the ink of 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, Other additives may be used. These may be used alone or in combination of two or more.

  Next, as a method for producing the ink-jet ink of the present invention, for example, the polymer composition of the present invention, an aqueous medium, an alkali such as sodium hydroxide is emulsified by high-speed stirring, a pigment is added, And a method of strongly dispersing in the above. 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 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 (Nanomizer).

  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 time to disperse, and unless the number of passes is extremely increased, a stable dispersion is difficult to obtain, which 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 within the aforementioned pressure range or by increasing the pressure, but the number of dispersions is at most 30 times from an economic viewpoint. It is desirable to obtain the desired dispersion form below.

  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 aforementioned alkaline solution include tertiary alkyl alkanolamines such as triethanolamine and tripropanolamine, and inorganic bases such as sodium hydroxide, potassium hydroxide and lithium hydroxide.

(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.

  500 parts by weight of Cyanine G-500 pure-A (CI PB15: 1; manufactured by Sanyo Dyeing Co., Ltd.) was mixed with 950 parts by weight of sulfolane, and 25 parts by weight of amidosulfuric acid was added thereto at 140 to 150 ° C. for 4 times. Stir for hours. The obtained slurry is put into 3000 parts by weight of ion-exchanged water, and a wet cake surface-treated with a centrifuge at 12000 rpm is obtained. This pigment wet cake was redispersed in 6000 parts by weight of ion-exchanged water and concentrated to a pigment concentration of 25% by ultrafiltration. This aqueous pigment dispersion showed weak acidity at pH 4.5 to 5.5.

  500 parts by weight of Monarch 800 (CI PBk7: manufactured by Cabot) was mixed with 950 parts by weight of sulfolane, 25 parts by weight of amidosulfuric acid was added, and the mixture was stirred at 140 to 150 ° C. for 8 hours. The obtained slurry is put into 3000 parts by weight of ion-exchanged water, and a wet cake surface-treated with a centrifuge at 12000 rpm is obtained. This pigment wet cake was redispersed in 6000 parts by weight of ion-exchanged water and concentrated to a pigment concentration of 25% by ultrafiltration. This aqueous pigment dispersion showed weak acidity at pH 4.5 to 5.5.

  500 parts by weight of Pigment Violet GC227-A was mixed in 1500 parts by weight of sulfolane, 25 parts by weight of amidosulfuric acid was added, and the mixture was stirred at 140 to 150 ° C. for 4 hours. The obtained slurry is put into 3000 parts by weight of ion-exchanged water, and a wet cake surface-treated with a centrifuge at 12000 rpm is obtained. This pigment wet cake was redispersed in 6000 parts by weight of ion-exchanged water and concentrated to a pigment concentration of 25% by ultrafiltration. This aqueous pigment dispersion showed weak acidity at pH 4.5 to 5.5.

  500 parts by weight of Fast Yellow 7413-A (CI PY74; manufactured by Sanyo Dye Co., Ltd.) was mixed in 1200 parts by weight of sulfolane, 25 parts by weight of amidosulfuric acid was added, and the mixture was stirred at 140 to 150 ° C. for 4 hours. The obtained slurry is put into 3000 parts by weight of ion-exchanged water, and a wet cake surface-treated with a centrifuge at 12000 rpm is obtained. This pigment wet cake was redispersed in 6000 parts by weight of ion-exchanged water and concentrated to a pigment concentration of 25% by ultrafiltration. This aqueous pigment dispersion showed weak acidity at pH 4.5 to 5.5.

  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. . Next, 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) are 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 having a resin solid content of 50%. After taking a part of the polymer composition solution thus obtained and drying for 1 hour in an oven at 105 ° C., the acid value of the solid of the polymer composition obtained is 50 mgKOH / g, The weight average molecular weight was 22000.

  Next, 3.0 parts by weight of a 30% aqueous sodium hydroxide solution was added to 120.0 parts by weight of the polymer composition solution thus prepared, and the mixture was stirred for 5 minutes with a high-speed disper. 480.0 parts by weight of the prepared Cyan surface-treated pigment was added and stirred with a high-speed disper for 1 hour to obtain a pigment-dispersed slurry. The pigment dispersion slurry was continuously dispersed 10 times at a pressure of 200 MPa with an ultrahigh pressure disperser (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 by a centrifuge (05P-21, manufactured by Hitachi, Ltd.). Then, ion-exchanged water was added so that the pigment concentration was 15% by weight to prepare a pigment dispersion. And it pressure-filtered using the 2.5 micrometer membrane filter (made by Advantech).

  Then, the ink for inkjet of the ink composition example A shown in Table 2 was created.

  In place of 38.8 parts by weight of acrylic acid, 85.3 parts by weight, and in addition to 7.5 parts by weight of t-butylperoxy (2-ethylhexanoate), t-butylperoxy (2-ethylhexanoate) E) The same procedure as in Example 5 was carried out except that the amount was 8.2 parts by weight. An inkjet ink of Composition Example A shown in Table 2 was produced. Moreover, after taking a part of polymer composition solution and drying for 1 hour with a high-temperature dryer at 105 ° C., the acid value of the solid matter of the obtained polymer composition for ink-jet ink is 110 mgKOH / g, and the weight average The molecular weight was 22000.

  966.0 parts by weight instead of 483.0 parts by weight of benzyl acrylate, 77.5 parts by weight instead of 38.8 parts by weight of acrylic acid, and 7.5 parts by weight of t-butylperoxy (2-ethylhexanoate) An ink-jet ink of Composition Example A shown in Table 2 was prepared in the same manner as in Example 5 except that the amount was changed to 2.88 parts by weight of t-butylperoxy (2-ethylhexanoate) instead of parts. Moreover, after taking a part of polymer composition solution and drying for 1 hour with a 105 degreeC high temperature drier, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 50 mgKOH / g, and is a weight average. The molecular weight was 115000.

  966.0 parts by weight instead of 483.0 parts by weight of benzyl acrylate, 170.5 parts by weight instead of 38.8 parts by weight of acrylic acid, and 7.5 parts by weight of t-butylperoxy (2-ethylhexanoate) An ink-jet ink of Composition Example A shown in Table 2 was prepared in the same manner as in Example 1 except that the amount was changed to 2.91 parts by weight of t-butylperoxy (2-ethylhexanoate) instead of parts. Moreover, after taking a part of polymer composition solution and drying for 1 hour with a high-temperature dryer at 105 ° C., the acid value of the solid matter of the obtained polymer composition for ink-jet ink is 110 mgKOH / g, and the weight average The molecular weight was 115000.

  Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Black surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 2 was used. This was carried out in the same manner as in Example 5 to prepare an inkjet ink of Composition Example B shown in Table 2.

  Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Black surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 2 was used. This was carried out in the same manner as in Example 6 to prepare an inkjet ink of Composition Example B shown in Table 2.

  Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Black surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 2 was used. This was carried out in the same manner as in Example 7 to prepare an inkjet ink of Composition Example B shown in Table 2.

  Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Black surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 2 was used. This was carried out in the same manner as in Example 8 to prepare an ink jet ink of Composition Example B shown in Table 2.

  Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Magenta surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 3 was used. This was carried out in the same manner as in Example 5 to prepare an inkjet ink of Composition Example C shown in Table 2.

  Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Magenta surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 3 was used. This was carried out in the same manner as in Example 6 to prepare an inkjet ink of Composition Example C shown in Table 2.

  Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Magenta surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 3 was used. This was carried out in the same manner as in Example 7 to prepare an inkjet ink of Composition Example C shown in Table 2.

  Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Magenta surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 3 was used. This was carried out in the same manner as in Example 8 to prepare an ink jet ink of Composition Example C shown in Table 2.

  Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Yellow surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 4 was used. In the same manner as in Example 5, an inkjet ink of Composition Example D shown in Table 2 was prepared.

  Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Yellow surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 4 was used. In the same manner as in Example 6, an inkjet ink of Composition Example D shown in Table 2 was prepared.

  Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Yellow surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 4 was used. In the same manner as in Example 7, ink-jet inks of Composition Example D shown in Table 2 were prepared.

  Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Yellow surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 4 was used. It carried out similarly to Example 8 and created the ink-jet ink of the composition example D shown in Table 2.

(Comparative Example 1)
In place of 38.8 parts by weight of acrylic acid, 31.0 parts by weight, and in addition to 7.5 parts by weight of t-butylperoxy (2-ethylhexanoate), t-butylperoxy (2-ethylhexanoate) was used. E) Except for 7.1 parts by weight, the same procedure as in Example 5 was carried out to prepare an ink jet ink of Composition Example A shown in Table 2. Moreover, after taking a part of polymer composition solution and drying for 1 hour with a 105 degreeC high temperature drier, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 40 mgKOH / g, and is a weight average. The molecular weight was 22000.

(Comparative Example 2)
In place of 38.8 parts by weight of acrylic acid, 100.8 parts by weight, and in addition to 7.5 parts by weight of t-butylperoxy (2-ethylhexanoate), t-butylperoxy (2-ethylhexanoate) E) The same procedure as in Example 5 was carried out except that the content was changed to 8.8 parts by weight. Ink jet inks of Composition Example A shown in Table 2 were prepared. Moreover, after taking a part of polymer composition solution and drying for 1 hour with a high-temperature drier at 105 ° C., the acid value of the solid matter of the obtained polymer composition for inkjet ink is 130 mgKOH / g, and the weight average The molecular weight was 22000.

(Comparative Example 3)
966.0 parts by weight instead of 483.0 parts by weight of benzyl acrylate, 62.0 parts by weight instead of 38.8 parts by weight of acrylic acid, and 7.5 parts by weight of t-butylperoxy (2-ethylhexanoate) An inkjet ink of Composition Example A shown in Table 2 was prepared in the same manner as in Example 5 except that the amount was changed to 2.87 parts by weight of t-butylperoxy (2-ethylhexanoate) instead of parts. Moreover, after taking a part of polymer composition solution and drying for 1 hour with a 105 degreeC high temperature drier, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 40 mgKOH / g, and is a weight average. The molecular weight was 115000.

(Comparative Example 4)
966.0 parts by weight instead of 483.0 parts by weight of benzyl acrylate, 201.5 parts by weight instead of 38.8 parts by weight of acrylic acid, and 7.5 parts by weight of t-butylperoxy (2-ethylhexanoate) An inkjet ink of Composition Example A shown in Table 2 was prepared in the same manner as in Example 5 except that the amount was changed to 2.92 parts by weight of t-butylperoxy (2-ethylhexanoate) instead of parts. Moreover, after taking a part of polymer composition solution and drying for 1 hour with a high-temperature drier at 105 ° C., the acid value of the solid matter of the obtained polymer composition for inkjet ink is 130 mgKOH / g, and the weight average The molecular weight was 115000.

(Comparative Example 5)
The aqueous pigment dispersion prepared in Example 1 was diluted with ion-exchanged water so that the pigment concentration of the aqueous pigment dispersion was 25% by weight to 15% by weight, and ink jet inks of ink composition examples A shown in Table 2 were prepared.

(Comparative Example 6)
Example 5 was repeated except that 7.9 parts by weight of t-butylperoxy (2-ethylhexanoate) was used instead of 7.5 parts by weight of t-butylperoxy (2-ethylhexanoate). The ink for inkjet of the composition example A shown in Table 2 was created. Moreover, after taking a part of polymer composition solution and drying for 1 hour with a 105 degreeC high temperature drier, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 50 mgKOH / g, and is a weight average. The molecular weight was 18000.

(Comparative Example 7)
In place of 38.8 parts by weight of acrylic acid, 85.3 parts by weight, and in addition to 7.5 parts by weight of t-butylperoxy (2-ethylhexanoate), t-butylperoxy (2-ethylhexanoate) E) The same procedure as in Example 5 was carried out except that the amount was changed to 8.6 parts by weight. An ink-jet ink of Composition Example A shown in Table 2 was produced. Moreover, after taking a part of polymer composition solution and drying for 1 hour with a high-temperature dryer at 105 ° C., the acid value of the solid matter of the obtained polymer composition for ink-jet ink is 110 mgKOH / g, and the weight average The molecular weight was 18000.

(Comparative Example 8)
966.0 parts by weight instead of 483.0 parts by weight of benzyl acrylate, 77.5 parts by weight instead of 38.8 parts by weight of acrylic acid, and 7.5 parts by weight of t-butylperoxy (2-ethylhexanoate) An inkjet ink of Composition Example A shown in Table 2 was prepared in the same manner as in Example 5 except that 2.86 parts by weight of t-butylperoxy (2-ethylhexanoate) was used instead of parts. Moreover, after taking a part of polymer composition solution and drying for 1 hour with a 105 degreeC high temperature drier, the acid value of the solid substance of the obtained polymer composition for inkjet inks is 50 mgKOH / g, and is a weight average. The molecular weight was 130,000.

(Comparative Example 9)
966.0 parts by weight instead of 483.0 parts by weight of benzyl acrylate, 170.5 parts by weight instead of 38.8 parts by weight of acrylic acid, and 7.5 parts by weight of t-butylperoxy (2-ethylhexanoate) An ink-jet ink of Composition Example A shown in Table 2 was prepared in the same manner as in Example 5 except that the amount was changed to 2.89 parts by weight of t-butylperoxy (2-ethylhexanoate) instead of parts. Moreover, after taking a part of polymer composition solution and drying for 1 hour with a high-temperature dryer at 105 ° C., the acid value of the solid matter of the obtained polymer composition for ink-jet ink is 110 mgKOH / g, and the weight average The molecular weight was 130,000.

(Comparative Example 10)
Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Black surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 2 was used. Then, the same procedure as in Comparative Example 1 was carried out to prepare an ink jet ink of Composition Example B shown in Table 2.

(Comparative Example 11)
Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Black surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 2 was used. In the same manner as in Comparative Example 2, an inkjet ink of Composition Example B shown in Table 2 was prepared.

(Comparative Example 12)
Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Black surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 2 was used. In the same manner as in Comparative Example 3, ink jet inks of Composition Example B shown in Table 2 were prepared.

(Comparative Example 13)
Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Black surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 2 was used. This was carried out in the same manner as in Comparative Example 4 to prepare an ink jet ink of Composition Example B shown in Table 2.

(Comparative Example 14)
The aqueous pigment dispersion prepared in Example 2 was diluted with ion-exchanged water so that the pigment concentration of the aqueous pigment dispersion was 25% by weight to 15% by weight, and ink jet inks of ink composition examples B shown in Table 2 were prepared.

(Comparative Example 15)
Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Magenta surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 3 was used. This was carried out in the same manner as in Comparative Example 1 to prepare an inkjet ink of Composition Example C shown in Table 2.

(Comparative Example 16)
Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Magenta surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 3 was used. Then, the same procedure as in Comparative Example 2 was performed, and an inkjet ink of Composition Example C shown in Table 2 was prepared.

(Comparative Example 17)
Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Magenta surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 3 was used. Then, the same procedure as in Comparative Example 3 was performed, and an inkjet ink of Composition Example C shown in Table 2 was prepared.

(Comparative Example 18)
Instead of 480.0 parts by weight of Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of Magenta surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 3 was used. The same procedure as in Comparative Example 4 was carried out to prepare an ink jet ink of Composition Example C shown in Table 2.

(Comparative Example 19)
The aqueous pigment dispersion prepared in Example 3 was diluted with ion-exchanged water so that the pigment concentration of the aqueous pigment dispersion was 25% by weight to 15% by weight, and ink for ink composition example C shown in Table 2 was prepared.

(Comparative Example 20)
Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Yellow surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 4 was used. Then, the same procedure as in Comparative Example 1 was carried out to prepare an ink jet ink of Composition Example D shown in Table 2.

(Comparative Example 21)
Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Yellow surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 4 was used. This was carried out in the same manner as in Comparative Example 2 to prepare an ink jet ink of Composition Example D shown in Table 2.

(Comparative Example 22)
Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Yellow surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 4 was used. Then, the same procedure as in Comparative Example 3 was performed, and an inkjet ink of Composition Example D shown in Table 2 was prepared.

(Comparative Example 23)
Instead of 480.0 parts by weight of the Cyan surface-treated pigment dispersion prepared in Example 1, 480.0 parts by weight of the Yellow surface-treated pigment dispersion having a pigment concentration of 25% by weight prepared in Example 4 was used. Then, the same procedure as in Comparative Example 4 was carried out to prepare an ink jet ink of Composition Example D shown in Table 2.

(Comparative Example 24)
The aqueous pigment dispersion prepared in Example 4 was diluted with ion-exchanged water so that the pigment concentration of the aqueous pigment dispersion was 25% by weight to 15% by weight, and ink jet inks of ink composition examples D shown in Table 2 were prepared.

(Evaluation Test 1: Evaluation Method for Colorability of Plain Paper)
The inkjet ink according to Examples 1 to 20 and Comparative Examples 1 to 24 was solid-printed on XeroxP paper (manufactured by Fuji Xerox Co., Ltd.) using an inkjet printer (EM-930C, manufactured by Seiko Epson Corporation). obtain. The print mode was paper: plain paper, print quality: super fine, color correction: none, print direction: bidirectional. And it is by measuring the OD value of each color using GRETAGMACBETH SPECTROSCANSP50 (made by Gretag (USA)). The results are shown in Table 1 as OD values.

(Evaluation Test 2: Glossiness Evaluation Method)
The ink jet inks according to Examples 1 to 20 and Comparative Examples 1 to 24 were solid-printed on photographic paper <gloss> (manufactured by Seiko Epson Corporation) with an ink jet printer (EM-930C, manufactured by Seiko Epson Corporation), and a test specimen Got. 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: Dispersibility Evaluation Method)
The average particle diameter of the particles in the inkjet inks according to Examples 1 to 20 and Comparative Examples 1 to 24 was measured with a laser particle size analyzer (Zeta Sizer 3000, manufactured by Malvern, UK). The results are shown in Table 1.

(Evaluation Test 4: Evaluation Method of Storage Stability)
The initial viscosity of the pigment dispersion for inkjet ink used in Examples 1 to 20 and Comparative Examples 1 to 24 and the viscosity after standing at 70 ° C. for 1 week were measured using a rolling ball viscometer (AMVn, Anton Paar (Germany) )). The results are shown in Table 1 as storage stability: viscosity (mPa · s) / initial viscosity (mPa · s) after standing at 70 ° C. for 1 week.

  Table 1 also shows the monomer composition, the polymerization initiator and the pigment, and the inkjet ink composition used when the inkjet ink was produced.

In addition, the symbol shown in Table 1-Table 2 is as follows.
BZA: benzyl acrylate AA: acrylic acid BPEH: t-butylperoxy (2-ethylhexanoate)
PBk7: C.I. I. Pigment Black 7 (carbon black)
PB15: 1: C.I. I. Pigment Blue 15: 1 (trichlorophthalocyanine)
PV19: C.I. I. Pigment Violet 19 (Quinacridone)
PY74: C.I. I. Pigment Yellow 74 (Condensed Azo Pigment)
DEGmBE: diethylene glycol monobutyl ether TEGmBE: triethylene glycol monobutyl ether PGmBE: propylene glycol monobutyl ether DPGmBE: dipropylene glycol monobutyl ether BEPD: 2-butyl-2-ethyl-1, 3-propanediol 1, 2-HD: 1, 2 -Hexanediol TMP: Trimethylolpropane EDTA: Disodium ethylenediaminetetraacetate

  As can be seen from the results in Tables 1 and 2, when the inkjet inks according to Examples 1 to 20 are used, all of the evaluation tests 1 to 5 are good results, but the inkjet inks according to Comparative Examples 1 to 24 are used. If it is, the evaluation test 1 to 5 will not give a good result in any one or a plurality of items.

Claims (5)

  Water, polymerized at least 50% by weight or more of benzyl acrylate and 15% by weight or less (meth) acrylic acid as a polymer component, and having an acid value of 50 mgKOH / g or more and 120 mgKOH / g or less, weight average molecular weight of 20000 or more An ink for ink jet recording, comprising: a pigment dispersion obtained by modifying a surface of a self-dispersing pigment particle with a polymer composition of 120,000 or less.   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 ink for inkjet recording according to claim 1, comprising at least one selected from alkylene oxide adducts of diols.   The ink for inkjet recording according to claim 1, comprising 1,2-alkylene glycol.   The ink for inkjet recording 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 ink for inkjet recording according to claim 1, comprising 2-butyl-2-ethyl-1,3-propanediol.