JP2007262109A - Ink for inkjet recording - Google Patents

Abstract

To provide an ink for ink jet recording having excellent stability, high color on plain paper, high gloss on glossy paper, and excellent clogging discharge stability.
An ink for ink jet recording according to the present invention comprises a coloring material and 2-butyl-2-methyl-1,3-propanediol. In addition, 2-butyl-2-
The amount of methyl-1,3-propanediol added is from 0.1% by weight to 5.0% by weight. Furthermore, 1,2-alkylene glycol is used.
[Selection figure] None

Description

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

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

The ink used for such ink-jet recording has no bleeding, good drying properties, can be printed uniformly on the surface of various recording media, color printing, etc. In color printing, characteristics such as that adjacent colors do not mix are required.

Many of the conventional inks, especially those that use pigments, mainly prevent penetration of the ink by suppressing the penetrability of the paper and keep the ink droplets close to the paper surface to ensure the print quality. It has been studied and put into practical use. However, with ink that suppresses wetting of paper, there is a large difference in bleeding due to differences in the type of paper, and especially with recycled paper that contains various paper components, there is bleeding due to differences in the wetting characteristics of each component. appear. In addition, with such inks, it takes time to dry the print, and there is a problem that adjacent colors are mixed in multicolor printing such as color printing, and further, the pigment is applied to the surface of paper or the like. Since it remains, there also exists a subject that abrasion resistance worsens.

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

In addition, in an ink using a pigment, it is generally difficult to improve the ink permeability while securing the dispersion stability of the pigment, and the selection range of the penetrant is narrowed. Combinations of glycol ethers and pigments include examples using triethylene glycol monomethyl ether as the pigment (see Patent Document 5), examples using ethers of ethylene glycol, diethylene glycol or triethylene glycol (see Patent Document 6), and the like. is there. There are also examples using 1,2-hexanediol, 1,2-octanediol, 2-methyl-2-propyl-1,3-propanediol, etc. (see Patent Document 7).

US Pat. No. 5,156,675 US Pat. No. 5,183,502 US Pat. No. 5,196,056 US Pat. No. 2,083,372 Japanese Patent Application Laid-Open No. 56-147861 Japanese Patent Laid-Open No. 9-111165 Japanese Patent Laid-Open No. 9-3371

However, conventional water-based inks have insufficient print quality, and are often smeared when printed on plain paper such as PPC paper, and color density and color developability are also insufficient. Further, the conventional pigment dispersion is unstable, and when a substance having a hydrophilic part and a hydrophobic part such as a surfactant or glycol ether is present, adsorption / desorption of the resin in which the pigment is dispersed to the pigment is likely to occur. There was a problem that the storage stability of the ink was poor. Further, a normal water-based ink requires a substance having a hydrophilic part and a hydrophobic part, such as a surfactant and glycol ether, in order to reduce bleeding on paper. Ink that does not use these substances has insufficient permeability to paper, and there is a problem in that the type of paper is limited in order to perform uniform printing, which tends to cause a reduction in the printed image.

Further, additives such as those used in the present invention (acetylene glycol-based and acetylene alcohol-based surfactants, di (tri) ethylene glycol monobutyl ether, (di) propylene glycol monobutyl ether, or 1,2 -Alkylene glycol or a mixture thereof), long-term storage stability is not obtained, and ink re-dissolvability is poor, so that the ink is dried and easily clogged at the tip of the nozzle of the inkjet head (
Clogging).

Therefore, the present invention solves such problems, and the object is to have excellent stability, high color on plain paper, high gloss on glossy paper, and stability of clogging out. Another object of the present invention is to provide an ink for ink jet recording excellent in the above.

The ink-jet ink of the present invention comprises a coloring material and 2-butyl-2-methyl-1,3-propanediol.

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

The ink for inkjet recording of the present invention comprises a coloring material, 2-butyl-2-methyl-1,3-
It is characterized by comprising propanediol. 2-butyl-2-methyl-1,3-
The amount of propanediol added is preferably 0.1% by weight or more and 5.0% by weight or less.
If it is less than 0.1% by weight, the color developability of plain paper is lowered, and the glossiness of glossy paper is also lowered to 5.0% by weight.
If it exceeds, the discharge stability will deteriorate.

The ink of the present invention preferably contains 1,2-alkylene glycol. The ink of the present invention preferably contains an acetylene glycol surfactant and / or an acetylene alcohol surfactant. The ink of the present invention preferably contains a pigment as the color material, and further contains a polymer having a glass transition temperature of 50 ° C. or lower used for dispersing the pigment. When the glass transition temperature exceeds 50 ° C., the color developability on plain paper decreases and the gloss on glossy paper also decreases.

In this way, by preparing the ink for ink jet recording, it is possible to obtain an ink jet ink that has high color on plain paper, high gloss on special paper, and excellent clogging stability.

Color materials that can be used in the present invention include dyes and / or pigments. As a dye,
Common dyes that can be used for inkjet can be used. Examples include colorants classified into oil-soluble dyes, basic dyes, etc. in addition to those classified as acid dyes, direct dyes, reactive dyes, vat dyes, sulfur dyes and food dyes in the color index. It can also be used. As the pigment, carbon black (C) such as furnace black, lamp black, acetylene black, and channel black is used for black ink.
. I. Pigment Black 7), or metal such as copper oxide, iron oxide (CI Pigment Black 11), titanium oxide, aniline black (CI Pigment Black 1)
However, for inkjet use, carbon black is preferable because it has a relatively low density and is difficult to settle in water.

Examples of pigments for color inks include C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 24, 34, 35
37, 42 (yellow iron oxide), 53, 55, 74, 81, 83 (disazo yellow HR)
, 93, 94, 95, 97, 98, 100, 101, 104, 108, 109, 110,
117, 120, 128, 138, 153, 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, C.I. I. Pigment violet 19, 23, C.I. I. Pigment orange 36, C.I. I. Pigment Blue 1, 2, 15 (phthalocyanine blue R), 15
: 15, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 16, 17: 1, 56, 60, 63, C.I. I. Pigment Green 1
4, 7, 8, 10, 17, 18, 36, etc. can be used.

As described above, various dyes and pigments can be used as the colorant. These are, for example, when dispersed using a polymer, when the dye is permeated into the polymer, or when fine polymer particles are used. It is preferable to use in the form of coexisting with a polymer.

When a pigment is used as the color material, the glass transition temperature of the polymer used for dispersing the pigment is 50 ° C.
The following is preferable. When the glass transition temperature exceeds 50 ° C., the fixing property on plain paper or glossy paper is deteriorated. It is preferable to use a glass transition temperature of 50 ° C. or lower in the present invention.
When butyl-2-methyl-1,3-propanediol is used, the glass transition temperature apparently further decreases, and the overlapping portion of dots on glossy paper is easily fused, and the leveling property of the dot surface is improved. The glossiness is improved. More preferably, 20 ° C. to 45
It is in the range of ° C.

When the colorant is a pigment, it is dispersed using a disperser. In this case, as the disperser, various commercially available dispersers can be used, and 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).

The addition amount of the coloring material is preferably 0.5 to 30% by weight, and more preferably 1.0 to 15% by weight. If the addition amount is 0.5% by weight or less, the print density cannot be secured. If the addition amount is 30% by weight or more, the viscosity of the ink increases and the structural property is generated in the viscosity characteristics, and the ejection stability of the ink from the inkjet head is reduced. It tends to get worse.

In addition, when a pigment is used as the coloring material, an alkylene glycol monoalkyl ether and / or 1,2-alkylene glycol is used in order to make the surface tension of the inkjet recording ink of the present invention in the range of 20 mN / m to 40 mN / m. It is preferable to add it. The alkylene glycol monoalkyl ether is preferably an alkylene glycol having 10 or less repeating units and an alkyl ether having 4 to 10 carbon atoms.
Tri) ethylene glycol monobutyl ether and / or (di) propylene glycol monobutyl ether are preferred. In addition, 1,2-alkylene glycol is
1,2-hexanediol and / or 1,2-pentanediol are preferred. These additions improve the dryness of printing, and even if printing is performed continuously, the previous printing portion is not transferred to the back surface of the next medium, so that high-speed printing is possible.

Moreover, it is preferable that the addition amount of an acetylene glycol-type surfactant and / or an acetylene alcohol-type surfactant is 0.1 to 5 weight%. In the present invention, the acetylene glycol surfactant and / or the acetylene alcohol surfactant is selected from di (tri) ethylene glycol monobutyl ether, (di) propylene glycol monobutyl ether and 1,2-alkylene glycol. It is preferable that 1 or more types are included. The addition amount of the acetylene glycol surfactant and / or the acetylene alcohol surfactant is 0.01% by weight to 0.5% by weight, and includes di (tri) ethylene glycol monobutyl ether, (di) propylene glycol monobutyl ether and The amount of one or more selected from 1,2-alkylene glycol is preferably 1% by weight or more.

In addition, as the ink-jet pigment ink in the present invention, ensuring its standing stability,
For the purpose of stable ejection from an inkjet head, improvement of clogging or prevention of ink deterioration, moisturizing agent, dissolution aid, penetration control agent, viscosity modifier, pH adjuster, dissolution aid, oxidation Various additives such as an inhibitor, an antiseptic, an antifungal agent, a corrosion inhibitor, and a chelate for capturing metal ions that affect the dispersion can also be added.

Hereinafter, specific embodiments of the present invention will be described in more detail. As examples, examples using pigments dispersed using the most preferred polymer are shown, but dyes can be used in the same manner, and the present invention is not limited to these examples.
Example 1

(1) Production of Pigment Dispersion 1 As the pigment dispersion 1, Monarch 880 manufactured by Cabot Corporation of the United States, which is carbon black (Pigment Black 7), was used. The reaction vessel equipped with a stirrer, thermometer, reflux tube and dropping funnel was purged with nitrogen, and then 65 parts of paracumylphenoxyethylene glycol acrylate, 10 parts of benzyl acrylate, 2 parts of acrylic acid, and 0.3 part of t-dodecyl mercaptan were added. Heated to 70 ° C and prepared separately, paracumylphenoxyethylene glycol acrylate 1
50 parts, 15 parts acrylic acid, 5 parts butyl acrylate, 1 part t-dodecyl mercaptan,
20 parts of methyl ethyl ketone and 1 part of sodium persulfate were placed in a dropping funnel and the dispersion polymer was subjected to a polymerization reaction while dropping into a reaction vessel over 4 hours. Next, methyl ethyl ketone was added to the reaction vessel to prepare a dispersion polymer solution having a concentration of 40%. A portion of this polymer was taken out and dried, and then the glass transition temperature was measured by a differential operation calorimeter (EXSTAR6000DSC, manufactured by Seiko Denshi).

Further, 40 parts of the dispersion polymer solution, 30 parts of Monarch 880 powder (manufactured by Cabot) as carbon black, 100 parts of a 0.1 mol / L aqueous sodium hydroxide solution, and 30 parts of methyl ethyl ketone were mixed. Then, using an ultra-high pressure homogenizer (Ultimizer HJP-25005 manufactured by Sugino Machine Co., Ltd.), it was dispersed by passing 15 passes at 200 MPa. Then, it moved to another container, 300 parts of ion-exchange water was added, and also it stirred for 1 hour. And the whole amount of methyl ethyl ketone and a part of water were distilled off using the rotary evaporator, and it neutralized with 0.1 mol / L sodium hydroxide, and adjusted to pH9. Then 0.3μ
m. A pigment dispersion 1 having a pigment concentration of 15% was prepared by filtering with a membrane filter and adjusting with ion exchange water.

(2) Production of Pigment Dispersion 2 Pigment Dispersion 2 was prepared in the same manner as Pigment Dispersion 1 using Pigment Blue 15: 1 (trichlorocopper phthalocyanine pigment: G500 manufactured by Sanyo Color Co., Ltd.).

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

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

(5) Preparation of inkjet recording ink Table 2 shows examples of compositions suitable for inkjet recording ink. The ink for inkjet recording of the present invention was prepared by using dispersions 1 to 4 prepared by the above method and mixing with the vehicle components shown in Table 2. In the remaining amount of water in Table 1, 0.05% by weight of the top side 240 (manufactured by Permachem Asia Co., Ltd.) was added to prevent corrosion of the ink, and benzotriazole was added to prevent corrosion of the ink jet head member. 02% by weight, 0% EDTA (ethylenediaminetetraacetic acid) 2Na salt to reduce the influence of metal ions in the ink system
. 04 wt% each added to ion exchange water was used.

(6) Evaluation of plain paper OD and glossy paper glossiness Xerox 4024 paper manufactured by US Xerox was used as plain paper, and PM photo paper manufactured by Seiko Epson Corporation was used as glossy paper. The printer used was an ink jet printer EM930C manufactured by Seiko Epson Corporation, and evaluation was performed using a sample printed with a printing mode of 720 dpi for plain paper and a printing mode of 1440 dpi for glossy paper. O
D is measured by GRETAG MACBETH SPECTROSC manufactured by GRETAG, USA
Performed using AN SPM-50. The glossiness was measured by measuring the specular glossiness of the recording surface at an incident angle of 60 degrees with a gloss checker IG-320 manufactured by HORIBA, Ltd., and taking the average of 5 times for each recording paper. The media is PM photo paper manufactured by Seiko Epson Corporation, and the printer is 720d using EM930C manufactured by Seiko Epson Corporation.
Printed in pi. The results are shown in Table 1. At the same time, as Comparative Examples 1 to 4 (Tables 3 to 6), 2
-It shows about the example compared about the presence or absence of addition of butyl-2-methyl-1, 3-propanediol and other additives.

(7) Measurement of clogging stability Using PX-V600 manufactured by Seiko Epson Corporation as an inkjet printer,
The number of cleanings (mechanism provided in the PX-V600 as a means for recovering missing dots) required for printing for 1 year in a 35% 35% atmosphere, which is a high temperature and low humidity environment, was measured. At the same time, as Comparative Examples 1 to 4 (Tables 3 to 6), 2-butyl-2-methyl-1,
It shows about the example compared about the presence or absence of addition of 3-propanediol and another additive.

（実施例２）

(Example 2)

(1) Production of Pigment Dispersion 5 Pigment Dispersion 5 is carbon black (PBk7) MA10 manufactured by Mitsubishi Chemical Industries, Ltd.
0 was used. The reaction vessel equipped with a stirrer, thermometer, reflux tube and dropping funnel was replaced with nitrogen, and then 45 parts of styrene, 30 parts of polyethylene glycol 400 acrylate, 10 parts of benzyl acrylate, 2 parts of acrylic acid, 0.3 part of t-dodecyl mercaptan 70 ℃
150 parts of styrene prepared separately, 100 parts of polyethylene glycol 400 acrylate, 15 parts of acrylic acid, 5 parts of butyl acrylate, 1 part of t-dodecyl mercaptan and 5 parts of sodium persulfate are placed in a dropping funnel over 4 hours. The dispersion polymer was polymerized while being dropped into the reaction vessel. Next, water was added to the reaction vessel to prepare a dispersed polymer solution having a concentration of 40%. A part of this polymer was taken and dried, and then the glass transition temperature was measured by a differential operation calorimeter (EXSTAR6000DSC manufactured by Seiko Denshi), and it was 45 ° C.

Further, 40 parts of the dispersion polymer solution and 30 parts of MA100 which is carbon black, 0 parts
. 100 parts of a 1 mol / L sodium hydroxide aqueous solution is mixed and dispersed over 2 hours using an Eiger mill using zirconia beads. Then, it transfers to another container, 300 parts of ion-exchange water is added, and also it stirs for 1 hour. And it neutralizes with 0.1 mol / L sodium hydroxide and adjusts to pH9. Then, filter with a 0.3μm membrane filter,
Dispersion 5 having a solid content (dispersion polymer and carbon black) of 20% was obtained.

(2) Production of Pigment Dispersion 6 Dispersion 6 was prepared in the same manner as Dispersion 5 using Pigment Blue 15: 4 (copper phthalocyanine pigment: manufactured by Clariant).

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

(4) Production of Pigment Dispersion 8 Dispersion 8 was Pigment Yellow 180 (diketopyrrolopyrrole pigment: manufactured by Clariant).
Was prepared in the same manner as dispersion 5.

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

(6) Evaluation of plain paper OD and glossy paper glossiness Evaluation of plain paper OD and glossy paper glossiness was carried out in the same manner as in Example 1. The results are shown in Table 7. Moreover, it shows about the example compared about the presence or absence of addition of 2-butyl-2-methyl-1, 3-propanediol and other additives simultaneously as Comparative Examples 5-8 (Tables 9-12).

(7) Measurement of clogging stability The clogging stability was measured in the same manner as in Example 1. The results are shown in Table 7. Moreover, it shows about the example compared about the presence or absence of addition of 2-butyl-2-methyl-1, 3-propanediol and other additives simultaneously as Comparative Examples 5-8 (Tables 9-12).

（実施例３〜実施例６）

(Example 3 to Example 6)

(1) Preparation of Inkjet Ink with Different Addition of 2-Butyl-2-methyl-1,3-propanediol The following are examples of compositions suitable for inkjet recording inks and 2-butyl-2- Example 3 in which the amount of methyl-1,3-propanediol added was changed
As shown in Tables 14 to 19 as -6 and Comparative Examples 9 and 10. The ink for inkjet recording was prepared in the same manner as in Example 1.

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

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

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

Claims (5)

An ink for ink jet recording comprising a coloring material and 2-butyl-2-methyl-1,3-propanediol. The ink for inkjet recording according to claim 1, wherein the addition amount of the 2-butyl-2-methyl-1,3-propanediol is 0.1 wt% or more and 5.0 wt% or less. The ink for inkjet recording according to claim 1 or 2, comprising 1,2-alkylene glycol. The ink for inkjet recording according to any one of claims 1 to 3, comprising an acetylene glycol surfactant and / or an acetylene alcohol surfactant. The ink for inkjet recording according to any one of claims 1 to 4, wherein the colorant is a pigment, and further contains a polymer having a glass transition temperature of 50 ° C or lower used for dispersing the pigment.