JP2007137995A - Ink composition for inkjet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink composition for inkjet that depresses discoloration caused by such a harmful gas as ozone, etc., and is excellent in injection stability and in maintenance of a nozzle surface after injection of an ink. <P>SOLUTION: The ink composition for inkjet comprises at least a water soluble dye, a fine resin particle, a water soluble organic solvent, and water, wherein, the water soluble organic solvent comprises a solvent composition whose molar fraction-converted vapor pressure (L) at 25°C defined by the formula is 6.00-10.67 Pa. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel inkjet ink composition and inkjet recording method.

  In recent years, the progress of inkjet technology has been remarkable, and in combination with improvements in printer technology, ink technology, and dedicated recording medium technology, high-quality image recording called photographic image quality has become possible.

  With the improvement in image quality, the storability of inkjet images has been compared with conventional silver salt photographs. Especially in dye inks, deterioration associated with movement of coloring materials such as water resistance and poor bleeding resistance of inkjet images In addition, deterioration accompanied by a chemical reaction peculiar to coloring materials such as light resistance and weakness to oxidation-resistant gas has been pointed out.

  In recent years, discoloration of ink jet recorded images due to ozone gas contained in a minute amount in the atmosphere has become a problem. In particular, in a void-type ink jet recording medium in which the ink absorption layer is composed of inorganic fine particles and a binder, a very remarkable fading phenomenon is recognized.

  Based on the above-mentioned present situation, an attempt has been made to form a resin film on the image surface for the purpose of improving the storage stability of the recorded image with dye ink.

  For example, a layer made of a thermoplastic organic polymer is provided on the outermost layer of an ink jet recording medium, and the thermoplastic organic polymer is melted and formed into a film after image recording, and as a result, a protective film of the polymer is formed. Improvement of weatherability and weather resistance and glossiness of an image are achieved (for example, see Patent Documents 1 to 4).

  Although this method is effective to some extent for improving image storage stability, it requires a special inkjet recording medium, requires a separate heat fixing device, and causes blistering due to evaporation of the ink solvent during heat fixing. However, there are many practical problems such as difficulty in control for forming an optimal image, such as film peeling and film peeling. In addition, since the outermost layer of thermoplastic organic polymer particles forms a continuous film, the ink absorbability is also impaired.

  Further, a method for improving water resistance and light resistance by adding latex or polymer fine particles to ink has been disclosed (for example, see Patent Document 5). Furthermore, a method of adding a resin to ink for the purpose of improving ozone gas resistance is disclosed (for example, see Patent Document 6), and a technique for adding latex or polymer fine particles to the ink (for example, Patent Documents 7 to 9). Reference).

  As described in each of the above patent documents, the technique of adding latex or polymer fine particles to the ink has a certain effect on improving the ozone gas resistance, but depending on the solvent composition, it may be contained in the latex or polymer fine particle film. Residual solvent remains, polymer molecules swell, and ozone gas resistance and weather resistance deteriorate easily.

  In addition, on the nozzle surface of the ink ejection head, after the ink is ejected, the polymer fine particle solution adheres to the nozzle surface and then dries and a resin film adheres. Depending on the solvent composition, the resin film is re-applied with new ink during re-ejection. Difficult to be dispersed, causing problems such as nozzle missing and bending.

As described above, with the conventional technology, it has been difficult to simultaneously satisfy the ozone gas resistance, weather resistance, nozzle surface maintenance, and emission stability.
JP 59-222381 A (Claims, Examples) JP-A-10-315448 (Claims, Examples) Japanese Patent Laid-Open No. 11-5362 (Claims, Examples) JP-A-11-192775 (Claims, Examples) Japanese Patent Laid-Open No. 11-199808 (Claims, Examples) JP 2002-240413 A (Claims, Examples) JP 2002-194253 A (Claims, Examples) JP 2002-264490 A (Claims, Examples) JP 2002-285049 A (Claims, Examples)

  SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to suppress ink fading caused by harmful gases such as ozone gas, and to provide an ink composition for ink jet that has excellent emission stability and maintainability of the nozzle surface after ink ejection. To provide things.

  The above object of the present invention can be achieved by the following configuration.

  1. It contains at least a water-soluble dye, resin fine particles, a water-soluble organic solvent and water, and the water-soluble organic solvent has a molar fraction converted vapor pressure (L) at 25 ° C. defined by the following formula of 6.00 to 10: An ink-jet ink composition comprising a solvent composition of .67 Pa.

L = La × na / (na + nb + nc +...) +
Lb × nb / (na + nb + nc +...) +
Lc × nc / (na + nb + nc +...) +.
(In the formula, La, Lb, Lc... Represent the vapor pressure of each solvent component at 25 ° C. of the water-soluble organic solvent components A, B, C... Contained in the ink composition, and a, b, c Represents the mass part (%) of each solvent component, and na, nb, nc,... Represent the number obtained by dividing each solvent component mass part (%) by the molecular weight of each solvent component.
2. 2. The ink-jet ink composition as described in 1 above, wherein the water-soluble organic solvent contains 10 to 20% by mass of a high-boiling water-soluble organic solvent having a boiling point of 250 ° C. or higher and lower than 300 ° C.

  3. The amount of the low-boiling organic solvent having a boiling point of less than 250 ° C. (part by mass) is 0.8 to 3 times the amount of the high-boiling water-soluble organic solvent having a boiling point of 250 ° C. or more and less than 300 ° C. (part by mass). 3. The inkjet ink composition as described in 1 or 2 above, wherein

  4). The ink composition for inkjet according to any one of 1 to 3, wherein the ink composition contains an amine compound.

  According to the present invention, it is possible to provide an ink-jet ink composition that suppresses fading due to a harmful gas such as ozone gas, and has excellent emission stability and maintainability of a nozzle surface after ink discharge.

  Hereinafter, the best mode for carrying out the present invention will be described in detail, but the present invention is not limited thereto.

  The inventor of the present invention provides ozone fading resistance (ozone resistance) obtained when an image of a water-based dye ink using resin fine particles is formed on a void-type ink jet recording medium (hereinafter simply referred to as a recording medium) and an ink discharge time. As a result of intensive studies on ejection stability and nozzle maintainability (redispersibility) after ejection, water solubility used in water-based dye inks to satisfy excellent ozone fading resistance, ejection stability, and nozzle maintenance at the same time It has been found that this can be achieved by an ink jet recording method using an ink composition composed of a solvent composition in which the molar fraction converted vapor pressure at 25 ° C. of the organic solvent is 6.00 to 10.67 Pa.

  In order for the image surface formed with an image on the recording medium to have good ozone resistance, it is necessary to form a uniform film in the melt film forming process using resin fine particles on the surface layer portion of the image surface. The melt film formation process follows the process of filling, fusing, and diffusing fine resin particles (Introduction to Polymer Latex, by Soichi Muroi), but a water-soluble organic solvent component (high boiling point organic solvent) that has a very slow drying rate in ink. ), It is presumed that the high-boiling organic solvent is confined in the gap between the fine particles in the diffusion process after the water evaporates and stays at the contact interface between the particles. Therefore, it is considered that the latex film becomes inhomogeneous and gas barrier properties and ozone resistance are deteriorated. On the other hand, if the ink drying speed is too high (mainly low boiling point organic solvent), the resin component adheres to the nozzle surface after ink ejection on the nozzle surface of the head and dries to form a hard resin film. It is presumed that the resin film is difficult to be re-dispersed with new ink, and that nozzles are likely to be missing or bent.

  The present inventor has found that the drying property of the water-soluble organic solvent can be expressed by the vapor pressure at 25 ° C. (room temperature), and the ink solvent composition and the drying property can be uniquely expressed. That is, the above-mentioned problem was solved by using a water-soluble organic solvent composition having a molar fraction converted vapor pressure defined by the following formula of 6.00 to 10.67 Pa for the ink.

In the ink composed of the solvent components A, B, C,..., And the mass parts (%) of the respective solvent components are a, b, c... And the molecular weights are Ma, Mb, Mc. The number of moles of each solvent component per 100 g is na = a / Ma, nb = b / Mb, nc = c / Mc, and the vapor pressure of each solvent component at 25 ° C. is La, Lb, Lc.
The molar fraction equivalent vapor pressure (L) of the water-soluble organic solvent in the present invention is L = La × na / (na + nb + nc +...)
+ Lb × nb / (na + nb + nc +...)
+ Lc × nc / (na + nb + nc +...) +.
It is defined as

  First, an ink containing at least a water-soluble dye, resin fine particles, a water-soluble organic solvent, and water will be described.

Examples of water-soluble dyes that can be used in the present invention include azo dyes, methine dyes, azomethine dyes, xanthene dyes, quinone dyes, phthalocyanine dyes, triphenylmethane dyes, diphenylmethane dyes, and the like. The compounds are shown below. However, it is not limited to these exemplified compounds.
[C. I. Acid Yellow)
1, 3, 11, 17, 18, 19, 23, 25, 36, 38, 40, 42, 44, 49, 59, 61, 65, 67, 72, 73, 79, 99, 104, 110, 114, 116, 118, 121, 127, 129, 135, 137, 141, 143, 151, 155, 158, 159, 169, 176, 184, 193, 200, 204, 207, 215, 219, 220, 230, 232, 235, 241, 242, 246
[C. I. Acid Orange)
3, 7, 8, 10, 19, 24, 51, 56, 67, 74, 80, 86, 87, 88, 89, 94, 95, 107, 108, 116, 122, 127, 140, 142, 144, 149, 152, 156, 162, 166, 168
[C. I. Acid Red)
1, 6, 8, 9, 13, 18, 27, 35, 37, 52, 54, 57, 73, 82, 88, 97, 106, 111, 114, 118, 119, 127, 131, 138, 143, 145, 151, 183, 195, 198, 211, 215, 217, 225, 226, 249, 251, 254, 256, 257, 260, 261, 265, 266, 274, 276, 277, 289, 296, 299, 315, 318, 336, 337, 357, 359, 361, 362, 364, 366, 399, 407, 415
[C. I. Acid Violet)
17, 19, 21, 42, 43, 47, 48, 49, 54, 66, 78, 90, 97, 102, 109, 126
[C. I. Acid Blue)
1, 7, 9, 15, 23, 25, 40, 62, 72, 74, 80, 83, 90, 92, 103, 104, 112, 113, 114, 120, 127, 128, 129, 138, 140, 142, 156, 158, 171, 182, 185, 193, 199, 201, 203, 204, 205, 207, 209, 220, 221, 224, 225, 229, 230, 239, 249, 258, 260, 264, 278, 279, 280, 284, 290, 296, 298, 300, 317, 324, 333, 335, 338, 342, 350
[C. I. Acid Green)
9, 12, 16, 19, 20, 25, 27, 28, 40, 43, 56, 73, 81, 84, 104, 108, 109
[C. I. Acid Brown)
2, 4, 13, 14, 19, 28, 44, 123, 224, 226, 227, 248, 282, 283, 289, 294, 297, 298, 301, 355, 357, 413
[C. I. Acid Black)
1, 2, 3, 24, 26, 31, 50, 52, 58, 60, 63, 107, 109, 112, 119, 132, 140, 155, 172, 187, 188, 194, 207, 222
[C. I. Direct yellow)
8, 9, 10, 11, 12, 22, 27, 28, 39, 44, 50, 58, 86, 87, 98, 105, 106, 130, 132, 137, 142, 147, 153
[C. I. (Direct orange)
6, 26, 27, 34, 39, 40, 46, 102, 105, 107, 118
[C. I. (Direct Red)
2, 4, 9, 23, 24, 31, 54, 62, 69, 79, 80, 81, 83, 84, 89, 95, 212, 224, 225, 226, 227, 239, 242, 243, 25 4
[C. I. Direct violet)
9, 35, 51, 66, 94, 95
[C. I. (Direct blue)
1, 15, 71, 76, 77, 78, 80, 86, 87, 90, 98, 106, 108, 160, 168, 189, 192, 193, 199, 200, 201, 202, 203, 218, 225, 229, 237, 244, 248, 251, 270, 273, 274, 290, 291
[C. I. (Direct Green)
26, 28, 59, 80, 85
[C. I. (Direct Brown)
44, 106, 115, 195, 209, 210, 222, 223
[C. I. (Direct Black)
17, 19, 22, 32, 51, 62, 108, 112, 113, 117, 118, 132, 146, 154, 159, 169
[C. I. Basic yellow)
1, 2, 11, 13, 15, 19, 21, 28, 29, 32, 36, 40, 41, 45, 51, 63, 67, 70, 73, 91
[C. I. Basic orange)
2, 21, 22
[C. I. (Basic Red)
1, 2, 12, 13, 14, 15, 18, 23, 24, 27, 29, 35, 36, 39, 46, 51, 52, 69, 70, 73, 82, 109
[C. I. Basic violet)
1, 3, 7, 10, 11, 15, 16, 21, 27, 39
[C. I. (Basic Blue)
1, 3, 7, 9, 21, 22, 26, 41, 45, 47, 52, 54, 65, 69, 75, 77, 92, 100, 105, 117, 124, 129, 147, 151
[C. I. Basic green)
1, 4
[C. I. Basic brown)
1
[C. I. (Reactive Yellow)
2, 3, 7, 15, 17, 18, 22, 23, 24, 25, 27, 37, 39, 42, 57, 69, 76, 81, 84, 85, 86, 87, 92, 95, 102, 105, 111, 125, 135, 136, 137, 142, 143, 145, 151, 160, 161, 165, 167, 168, 175, 176
[C. I. (Reactive Orange)
1, 4, 5, 7, 11, 12, 13, 15, 16, 20, 30, 35, 56, 64, 67, 69, 70, 72, 74, 82, 84, 86, 87, 91, 92, 93, 95, 10 7
[C. I. (Reactive Red)
2, 3, 5, 8, 11, 21, 22, 23, 24, 28, 29, 31, 33, 35, 43, 45, 49, 55, 56, 58, 65, 66, 78, 83, 84, 106, 111, 112, 113, 114, 116, 120, 123, 124, 128, 130, 136, 141, 147, 158, 159, 171, 174, 180, 183, 184, 187, 190, 193, 194, 195, 198, 218, 220, 222, 223, 228, 235
[C. I. (Reactive Violet)
1, 2, 4, 5, 6, 22, 23, 33, 36, 38
[C. I. (Reactive Blue)
2, 3, 4, 5, 7, 13, 14, 15, 19, 21, 25, 27, 28, 29, 38, 39, 41, 49, 50, 52, 63, 69, 71, 72, 77, 79, 89, 104, 109, 112, 113, 114, 116, 119, 120, 122, 137, 140, 143, 147, 160, 161, 162, 163, 168, 171, 176, 182, 184, 191, 194, 195, 198, 203, 204, 207, 209, 211, 214, 220, 221, 222, 231, 235, 236
[C. I. (Reactive Green)
8, 12, 15, 19, 21
[C. I. (Reactive Brown)
2, 7, 9, 10, 11, 17, 18, 19, 21, 23, 31, 37, 43, 46 [C. I. (Reactive Black)
5, 8, 13, 14, 31, 34, 39, and the like. These dyes listed above are described in “Dyeing Note 21st Edition” (published by Color Dyeing).

  Of the water-soluble dyes shown above, phthalocyanine dyes are preferred. Examples of the phthalocyanine dye include those that are unsubstituted or have a central element. Examples of the central element include those that are metallic and nonmetallic, preferably copper, and more preferably C.I. I. Direct blue 199 is mentioned.

  The resin fine particles according to the present invention refer to polymer particles dispersed in a medium, for example, water, and are also called polymer fine particles or latex.

  The resin fine particles can be used in the form of an aqueous dispersion of various polymers. Specifically, acrylic, styrene-acrylic, styrene-butadiene, acrylonitrile-acrylic, vinyl acetate, vinyl acetate-acrylic, vinyl acetate-vinyl chloride, polyurethane, polyethylene, silicon-acrylic , Acrylic silicon-based, polyester-based, and epoxy-based polymers.

  Usually, these resin fine particles are obtained by an emulsion polymerization method. The surfactants, polymerization initiators, etc. used there may be those used in conventional methods. Regarding the synthesis method of resin fine particles, U.S. Pat. Nos. 2,852,368, 2,853,457, 3,411,911, 3,411,912, 4,197,127, Belgian Patent Nos. 688,882, 691,360, 712,823, JP-B 45-5331, JP-A-60-18540, 51-130217, 58-137831, 55- 50240 and the like.

  The resin fine particles used in the ink according to the present invention preferably have an average particle size of 10 to 200 nm, more preferably 10 to 150 nm.

  If the average particle diameter of the resin fine particles is 10 nm or more, the resin fine particles do not penetrate into the void layer and are present on the surface of the void layer, which is preferable in terms of gloss. If the average particle size of the resin fine particles is 200 nm or less, the resin fine particles are small to some extent, which is advantageous from the viewpoint of leveling properties on the surface of the void layer, and is preferable in terms of gloss.

  The average particle size of the resin fine particles can be easily obtained using a commercially available particle size measuring device using a light scattering method or a laser Doppler method, for example, Zetasizer 1000 (manufactured by Malvern).

  In the ink according to the present invention, the content of the resin fine particles in the ink is preferably 0.2 to 10% by mass, and more preferably 0.5 to 5% by mass. If the addition amount of the resin fine particles is 0.2% by mass or more, a sufficient effect on ozone resistance can be exhibited, and if it is 10% by mass or less, the ink ejection property becomes more stable and further preserved. It is more preferable because it can suppress an increase in ink viscosity.

  In the resin fine particles according to the present invention, the minimum film-forming temperature (MFT) is preferably 0 to 60 ° C. In the present invention, a film-forming aid may be added to control the minimum film-forming temperature of the resin fine particles. The film-forming aid, also called a plasticizer, is an organic compound (usually an organic solvent) that lowers the minimum film-forming temperature of the polymer latex. For example, “Synthetic Latex Chemistry (Souichi Muroi, published by Kobunshi Shuppankai (1970)” )"It is described in.

  The organic solvent that can be used in the present invention is preferably a water-soluble organic solvent. Specifically, alcohols (for example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc.), polyhydric alcohols (for example, ethylene) Glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, etc.), polyhydric alcohol ethers (for example, ethylene) Glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono Chill ether, ethylene glycol monophenyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol mono Ethyl ether, triethylene glycol monobutyl ether, triethylene glycol dimethyl ether, dipropylene glycol monopropyl ether, tripropylene glycol dimethyl ether, etc.), amines (eg, ethanolamine, diethanolamine, triethanol) Amines, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.), amides ( For example, formamide, N, N-dimethylformamide, N, N-dimethylacetamide and the like), heterocyclic rings (eg, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone etc.), sulfoxides (eg dimethyl sulfoxide etc.), sulfones (eg sulfolane etc.), sulfonates (eg 1-butanesulfonic acid) Sodium salt), urea, acetonitrile, acetone and the like.

  In particular, it is preferable to use polyhydric alcohols, polyhydric alcohol ethers and amines in combination. In particular, the resin fine particles (latex) in the ink have a property that the resin fine particles are likely to aggregate in an acidic solution. In particular, the surface layer of an inkjet recording medium is often acidic, and the pH drops after the ink has landed on the recording medium, causing the resin fine particles to agglomerate, making it difficult to form a uniform film during the drying process.

  Addition of amines makes the ink basic, maintains a basic pH of 7 or more even after the ink has landed on the recording medium, prevents agglomeration of resin fine particles, and melt film formation process in the drying process It is assumed that a uniform film is formed in

  Various surfactants can be used in the ink according to the present invention. The surfactant that can be used in the present invention is not particularly limited, but examples thereof include anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxy Nonionic surfactants such as ethylene alkylallyl ethers, acetylene glycols, polyoxyethylene / polyoxypropylene block copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. In particular, an anionic surfactant and a nonionic surfactant can be preferably used.

  In the ink of the present invention, a polymer surfactant can also be used. For example, styrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid copolymer, styrene-maleic acid-acrylic acid. Alkyl ester copolymer, styrene-maleic acid copolymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-methacrylic acid copolymer, styrene-maleic acid half ester copolymer, vinyl naphthalene-acrylic acid A copolymer, a vinyl naphthalene-maleic acid copolymer, etc. can be mentioned.

  Next, the ink jet recording method of the present invention will be described.

  In the ink jet recording method of the present invention, the recording head is used to apply the ink of the water-based ink set for ink jet according to the present invention to the recording medium, and the ink droplet amount per discharge operation is 0.5 to 3.0 pl. A range of (picoliter) is preferable because the gloss of the printed portion and the ink absorption speed are further improved. In the present invention, the ink droplet amount per discharge operation defines the volume of a single ink droplet discharged from one nozzle of the head as the ink droplet amount.

In the ink jet recording method of the present invention, as means for realizing the ink droplet amount per discharge operation specified in the present invention, for example, the diameter of the emission nozzle provided in the recording head, the piezoelectric element provided in the recording head, This can be realized by appropriately adjusting the applied voltage, the pulse applied to the electrode of the piezoelectric element, and the like.
Discharge methods include electro-mechanical conversion methods (eg, single cavity type, double cavity type, bender type, piston type, shear mode type, shared wall type, etc.), electro-thermal conversion methods (eg, thermal ink jet type) , Bubble jet (registered trademark) type), electrostatic suction type (for example, electric field control type, slit jet type, etc.) and discharge type (for example, spark jet type, etc.), preferably continuous injection A head using a piezo method having excellent properties is preferable.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

<Preparation of ink>
Example 1
C. I. Direct Blue 199 3% by mass
Glycerin (boiling point: 290 ° C., molecular weight: 92.1) 8% by mass
Triethylene glycol monobutyl ether (boiling point: 260-270 ° C., molecular weight: 206.3) 4% by mass
Propylene glycol (boiling point: 187.4, molecular weight: 76.1) 14% by mass
1,2-hexanediol (boiling point: 223 ° C., molecular weight: 118.2) 10% by mass
Resin fine particle emulsion (trade name: SX1105 manufactured by Nippon Zeon Co., Ltd. average particle size: 108 nm, Tg = 0 ° C.)
1% by mass
Triethanolamine 0.5% by mass
Surfactant (Olfin E1010 Nissin Chemical Industry Co., Ltd.) 0.5% by mass
Remaining amount of ion-exchanged water The above compositions were mixed and stirred, and then filtered through a filter having a filtration diameter of 1 μm to prepare cyan ink 1. Assuming that the addition ratio of the high-boiling solvent having a boiling point of 250 to 300 ° C. is VH (mass%) and the addition ratio of the low-boiling organic solvent having a boiling point of less than 250 ° C. is VL (mass%), VH = 12 mass%, VL / VH = 2 and the vapor pressure in terms of mole fraction at 25 ° C. was 8.53 Pa.

Example 2
In Example 1, the same method was used except that SX1105 (styrene butadiene resin fine particle emulsion) was changed to SR108 (styrene butadiene resin fine particle emulsion, average particle diameter: 116 nm, Tg = −9 ° C., manufactured by Nippon A & L). Ink 2 was prepared.

  The drying factor of the water-soluble organic solvent was VH = 12% by mass and VL / VH = 2, as in Example 1, and the molar fraction converted vapor pressure at 25 ° C. was 8.53 Pa.

Example 3
In Example 1, the same method was used except that SX1105 (styrene butadiene resin fine particle emulsion) was changed to SF150 (urethane resin fine particle emulsion, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., average particle size: 91 nm, Tg = 40 ° C.). Ink 3 was prepared.

  The drying factor of the water-soluble organic solvent was VH = 12% by mass and VL / VH = 2, as in Example 1, and the molar fraction converted vapor pressure at 25 ° C. was 8.53 Pa.

Example 4
C. I. Direct Blue 199 3% by mass
Glycerin (boiling point: 290 ° C., molecular weight: 92.1) 10% by mass
Triethylene glycol monobutyl ether (boiling point: 260-270 ° C., molecular weight: 206.3) 5% by mass
Propylene glycol (boiling point: 187.4, molecular weight: 76.1) 10% by mass
1,2-hexanediol (boiling point: 223 ° C., molecular weight: 118.2) 5% by mass
Resin fine particle emulsion (trade name: SX1105 manufactured by Nippon Zeon Co., Ltd. average particle size: 108 nm, Tg = 0 ° C.)
1% by mass
Triethanolamine 0.5% by mass
Surfactant (Olfin E1010 Nissin Chemical Industry Co., Ltd.) 0.5% by mass
Ion-exchanged water The remaining ink was prepared in the same manner as in Example 1 to prepare cyan ink 4.

  The drying factor of the water-soluble organic solvent is VH = 15% by mass, VL / VH = 1, and the molar fraction converted vapor pressure at 25 ° C. is 7.33 Pa.

Example 5
C. I. Direct Red 227 3% by mass
Glycerin (boiling point: 290 ° C., molecular weight: 92.1) 12% by mass
Triethylene glycol monobutyl ether (boiling point: 260-270 ° C., molecular weight: 206.3) 6% by mass
Propylene glycol (boiling point: 187.4, molecular weight: 76.1) 10% by mass
1,2-hexanediol (boiling point: 223 ° C., molecular weight: 118.2) 5% by mass
Resin fine particle emulsion (trade name: SX1105 manufactured by Nippon Zeon Co., Ltd. average particle size: 108 nm, Tg = 0 ° C.)
1% by mass
Triethanolamine 0.5% by mass
Surfactant (Olfin E1010 Nissin Chemical Industry Co., Ltd.) 0.5% by mass
Residual amount of ion-exchanged water The ink was prepared in the same manner as in Example 1 to prepare magenta ink 1.

  The drying factor of the water-soluble organic solvent is VH = 18% by mass, VL / VH = 0.83, and the vapor pressure in terms of mole fraction at 25 ° C. is 6.80 Pa.

Example 6
C. I. Direct Blue 199 3% by mass
Glycerin (boiling point: 290 ° C., molecular weight: 92.1) 10% by mass
Propylene glycol (boiling point: 187.4, molecular weight: 76.1) 24% by mass
1,2-hexanediol (boiling point: 223 ° C., molecular weight: 118.2) 6% by mass
Resin fine particle emulsion (trade name: SX1105 manufactured by Nippon Zeon Co., Ltd. average particle size: 108 nm, Tg = 0 ° C.)
1% by mass
Triethanolamine 0.5% by mass
Surfactant (Olfin E1010 Nissin Chemical Industry Co., Ltd.) 0.5% by mass
Remaining amount of ion-exchanged water Ink was prepared in the same manner as in Example 1 to prepare cyan ink 5.

  The drying factor of the water-soluble organic solvent is VH = 10% by mass, VL / VH = 3, and the molar fraction converted vapor pressure at 25 ° C. is 10.53 Pa.

Example 7
C. I. Direct Blue 199 3% by mass
Glycerin (boiling point: 290 ° C., molecular weight: 92.1) 10% by mass
Propylene glycol (boiling point: 187.4, molecular weight: 76.1) 8% by mass
1,2-hexanediol (boiling point: 223 ° C., molecular weight: 118.2) 20% by mass
Resin fine particle emulsion (trade name: SX1105 manufactured by Nippon Zeon Co., Ltd. average particle size: 108 nm, Tg = 0 ° C.)
1% by mass
Triethanolamine 0.5% by mass
Surfactant (Olfin E1010 Nissin Chemical Industry Co., Ltd.) 0.5% by mass
Remaining amount of ion-exchanged water Ink was prepared in the same manner as in Example 1 to prepare cyan ink 6.

  The drying factor of the water-soluble organic solvent is VH = 10% by mass, VL / VH = 2.8, and the molar fraction converted vapor pressure at 25 ° C. is 6.00 Pa.

Example 8
In Example 1, cyan ink 7 was prepared by exactly the same method except that triethanolamine was not added.

  The drying factor of the water-soluble organic solvent was VH = 12% by mass and VL / VH = 2, as in Example 1, and the molar fraction converted vapor pressure at 25 ° C. was 8.53 Pa.

Comparative Example 1
C. I. Direct Blue 199 3% by mass
Glycerin (boiling point: 290 ° C., molecular weight: 92.1) 23% by mass
Triethylene glycol monobutyl ether (boiling point: 260-270 ° C., molecular weight: 206.3) 5% by mass
Propylene glycol (boiling point: 187.4, molecular weight: 76.1) 5% by mass
1,2-hexanediol (boiling point: 223 ° C., molecular weight: 118.2) 10% by mass
Resin fine particle emulsion (trade name: SX1105 manufactured by Nippon Zeon Co., Ltd. average particle size: 108 nm, Tg = 0 ° C.)
1% by mass
Triethanolamine 0.5% by mass
Surfactant (Olfin E1010 Nissin Chemical Industry Co., Ltd.) 0.5% by mass
Remaining amount of ion-exchanged water Ink was prepared in the same manner as in Example 1 to prepare cyan ink 8.

  The drying factor of the water-soluble organic solvent is VH = 28% by mass, VL / VH = 0.54, and the vapor pressure in terms of mole fraction at 25 ° C. is 3.33 Pa.

Comparative Example 2
C. I. Direct Blue 199 3% by mass
Glycerin (boiling point: 290 ° C., molecular weight: 92.1) 10% by mass
Triethylene glycol monobutyl ether (boiling point: 260-270 ° C., molecular weight: 206.3) 20% by mass
Propylene glycol (boiling point: 187.4, molecular weight: 76.1) 6% by mass
1,2-hexanediol (boiling point: 223 ° C., molecular weight: 118.2) 4% by mass
Resin fine particle emulsion (trade name: SX1105 manufactured by Nippon Zeon Co., Ltd. average particle size: 108 nm, Tg = 0 ° C.)
1% by mass
Triethanolamine 0.5% by mass
Surfactant (Olfin E1010 Nissin Chemical Industry Co., Ltd.) 0.5% by mass
Remaining amount of ion-exchanged water Ink was prepared in the same manner as in Example 1 to prepare cyan ink 9.

  The drying factor of the water-soluble organic solvent is VH = 30% by mass, VL / VH = 0.33, and the molar fraction converted vapor pressure at 25 ° C. is 5.07 Pa.

Comparative Example 3
C. I. Direct Blue 199 3% by mass
Glycerin (boiling point: 290 ° C., molecular weight: 92.1) 6% by mass
Triethylene glycol monobutyl ether (boiling point: 260-270 ° C., molecular weight: 206.3) 4% by mass
Propylene glycol (boiling point: 187.4, molecular weight: 76.1) 26% by mass
1,2-hexanediol (boiling point: 223 ° C., molecular weight: 118.2) 6% by mass
Resin fine particle emulsion (trade name: SX1105 manufactured by Nippon Zeon Co., Ltd. average particle size: 108 nm, Tg = 0 ° C.)
1% by mass
Triethanolamine 0.5% by mass
Surfactant (Olfin E1010 Nissin Chemical Industry Co., Ltd.) 0.5% by mass
Remaining amount of ion-exchanged water Ink was prepared in the same manner as in Example 1 to prepare cyan ink 10.

  The drying factor of the water-soluble organic solvent is VH = 10% by mass, VL / VH = 3.2, and the vapor pressure in terms of mole fraction at 25 ° C. is 11.33 Pa.

  Table 1 shows the ink formulations used in Examples 1 to 7 and Comparative Examples 1 to 3, the particle size of the resin fine particle emulsion (latex), the glass transition point (Tg), and the like.

In the table, the abbreviations for water-soluble organic solvents are as follows:
GLY: Glycerin TEGBE: Triethylene glycol-monobutyl ether PG: Propylene glycol 1,2-HDD: 1,2-hexanediol TEA: Triethanolamine.

<Inkjet recording>
Each ink prepared in the ink formulation shown in Table 1 is refilled into an ink cartridge of an ink jet printer PM880C (manufactured by Seiko Epson Corp.) to be in a printable state, and on the recording medium, standard conditions for PM photo paper mode as printing conditions Then, a solid image having a density of about 1.0 was printed to prepare a print sample. As the recording medium, “QP-pro photo gloss G (manufactured by Konica Photo Imaging)”, which is a void-type recording paper, was used.

  The following evaluation was performed and the results are shown in Table 2.

[Evaluation of ozone fading resistance]
The produced cyan and magenta solid images having a density of about 1.0 were exposed at an ozone concentration of 10 ppm for 20 hours using an ozone tester (Ozone Weather Meter OMS-H manufactured by Suga Test Instruments Co., Ltd.). After exposure, the cyan density was measured, the residual density ratio (cyan or magenta density after ozone treatment / cyan or magenta density before ozone treatment × 100%) was determined, and ozone fading resistance was evaluated according to the following criteria.

A: Cyan density residual ratio is 90% or more B: Cyan density residual ratio is 80% to 89% Δ: Cyan density residual ratio is 70% to 79% X: Cyan density residual ratio is 69% or less It is.

[Evaluation of maintainability]
Using a microsyringe, each ink prepared according to the ink formulation shown in Table 1 was dropped on a support base coated with a fluorine-based resin on a PET-based surface having a thickness of 100 μm, and a 3 μL ink droplet was dropped at room temperature. Let stand for 1 day (24 hours) and dry. After 1 day, again drop 3 μL of the same ink drop on the same, scrape the ink drop with a urethane rubber blade, and check if the latex resin film remains after the ink. Observation was made using “DS-3U” and the maintainability (ink redispersibility) was evaluated according to the following criteria.

○: Resin film and dirt were not observed at all Δ: Resin film made of latex that looked slightly white was left ×: Resin film made of latex was clearly observed in the trace of droplets.

(Evaluation of light emission)
Each ink produced according to the ink formulation shown in Table 1 is ejected by continuously ejecting each ink for one hour at a driving frequency of 8.2 kHz and an ejection speed of 10 m / s using an on-demand piezo shear mode drive type ink jet printer having 64 ejection nozzles. The emission was evaluated according to the following criteria.

○: No nozzle missing or bend when continuously ejected for 1 hour △: 1 or 2 exiting curves occurred when continuously ejected for 1 hour ×: 1 nozzle missing when continuously ejected for 1 hour More than three or more than three exit curves.

  As is apparent from the results in Table 2, the inks of the present inventions 1 to 8 in which the vapor pressure of the water-soluble organic solvent in terms of mole fraction at 25 ° C. is 6.00 to 10.67 Pa are ozone fading resistance and maintainability. In Comparative Examples 1 to 3, which are good results in both emission characteristics, the vapor pressure is out of the range. Evaluation of any of ozone fading resistance, maintainability (redispersibility), or output characteristics It can be seen that the items are greatly inferior. “Invention 6”, whose vapor pressure is close to the upper limit of the vapor pressure range of the present invention, has extremely good ozone fading resistance, but results in slightly poor maintainability and emission properties, and the vapor pressure is the vapor pressure of the present invention. “Invention 7” near the lower limit of the pressure range was good in maintainability and emission, but was slightly inferior in ozone fading resistance. In addition, “Invention 8” containing no triethanolamine was somewhat inferior to “Invention 1-5” in both ozone fading resistance and emission.

  From the above, the inks of the present inventions 1 to 8 in which the vapor pressure of the water-soluble organic solvent in terms of mole fraction at 25 ° C. has good ozone resistance, maintainability, and emission properties, particularly amine compounds such as triethanolamine. It has been clarified that when the is added, the effect of the above characteristics is further exhibited.

Claims (4)

It contains at least a water-soluble dye, resin fine particles, a water-soluble organic solvent and water, and the water-soluble organic solvent has a molar fraction converted vapor pressure (L) at 25 ° C. defined by the following formula of 6.00 to 10: An ink-jet ink composition comprising a solvent composition of .67 Pa.
L = La × na / (na + nb + nc +...) +
Lb × nb / (na + nb + nc +...) +
Lc × nc / (na + nb + nc +...) +.
(In the formula, La, Lb, Lc... Represent the vapor pressure of each solvent component at 25 ° C. of the water-soluble organic solvent components A, B, C... Contained in the ink composition, and a, b, c Represents the mass part (%) of each solvent component, and na, nb, nc,... Represent the number obtained by dividing each solvent component mass part (%) by the molecular weight of each solvent component. The inkjet ink composition according to claim 1, wherein the water-soluble organic solvent contains 10 to 20% by mass of a high-boiling water-soluble organic solvent having a boiling point of 250 ° C or higher and lower than 300 ° C. The amount of the low-boiling organic solvent having a boiling point of less than 250 ° C. (part by mass) is 0.8 to 3 times the amount of the high-boiling water-soluble organic solvent having a boiling point of 250 ° C. or more and less than 300 ° C. (part by mass). It contains so that it may become. The ink composition for inkjet of Claim 1 or 2 characterized by the above-mentioned. The ink composition for inkjet according to any one of claims 1 to 3, wherein the ink composition contains an amine compound.