JP2005220268A - Black compound and ink containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a black compound for ink jet ink that has excellent humidity resistance, light stability, stability against gases, and storing stability. <P>SOLUTION: This black compound is represented by general formula (1), wherein n is an integer of 2-12; and Ms are, independently from each other, an alkali metal, amine, or quaternary ammonium where at least one of the plural Ms is a quaternary ammonium. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a novel black compound and an ink thereof, and more particularly to an ink suitable for an ink jet recording system.

  Ink used for writing instruments or ink jet recording systems is basically composed of dye, water and organic solvent, but water is mainly used in consideration of odor, safety to human body and surrounding environment. Water-based ink as a solvent is the mainstream, and water-soluble acid dyes and direct dyes are put to practical use as dyes. In this regard, various characteristics are required for dyes and inks.

In particular, the ink used for the recording liquid of the ink jet recording method has various required characteristics as described below, but the current situation is that the ink cannot satisfy all the requirements.
(1) Appropriate physical properties such as ink viscosity, surface tension, specific conductivity, density, and pH.
(2) The ink has good long-term storage stability.
(3) The dissolution stability of the dissolved component is high and the nozzle is not clogged.
(4) Quick drying on the recording material is good.
(5) The recorded image is clear, has no bleeding, and has good light resistance, gas resistance, water resistance, and moisture resistance.

  Examples of conventionally known black dyes include disazo dyes disclosed in Acid Black 1, Patent Document 1, etc., metal chelate azo dyes disclosed in Patent Document 2, etc., or disclosed in Patent Document 3, etc. Examples of trisazo dyes. However, these azo dyes are still insufficient in terms of fastness such as light resistance. Patent Document 4 discloses that a built-up dyestuff is sulfonated into sodium salt, potassium salt, lithium salt, ethanolamine salt to obtain a highly light-resistant black dye, which is applied to inkjet ink. However, these salts have insufficient solubility as an ink, so that the storage stability of the ink is low, and the stability (gas resistance) against an oxidizing gas such as ozone is insufficient.

As described above, the characteristics of the ink used in the ink jet recording method are greatly affected by the characteristics inherent to the dye, and the creation of dyes and inks that satisfy these various conditions is extremely important.
JP 2003-138155 A JP 2002-30229 A Japanese Patent Laid-Open No. 5-93143 Japanese Patent Laid-Open No. 2003-238871

  An object of the present invention is to provide a novel black compound having high light resistance, high storage stability, and high gas resistance, an ink retaining the characteristics of the compound, and no bleeding with high image quality, storage stability, and light resistance. Another object of the present invention is to provide an ink useful as a recording liquid of an ink jet recording system having excellent properties, gas resistance and moisture resistance.

  As a result of intensive studies to solve the above problems, the present inventors have found that the compound of the present invention has high light resistance and gas resistance and can be used as a black dye, and inks using the compound are also excellent. The inventors have found that the characteristics can be exhibited while maintaining light resistance and gas resistance, and have completed the present invention.

  That is, the present invention relates to a black compound represented by the following general formula (1) and an ink containing the same.

  [Wherein n represents an integer of 2 to 12. Each M independently represents an alkali metal, an amine, or quaternary ammonium, and at least one of the plurality of M is quaternary ammonium. ]

  The black compound of the present invention and the ink using the same are excellent in moisture resistance, light resistance and gas resistance, and have high ink storage stability, and are particularly useful for ink jet ink applications.

The present invention relates to a black compound represented by the general formula (1) and an ink containing the black compound. Hereinafter, the present invention will be described in more detail.
First, the black compound represented by the following general formula (1) in the present invention will be described.

  [Wherein n represents an integer of 2 to 12. Each M independently represents an alkali metal, an amine, or quaternary ammonium, and at least one of the plurality of M is quaternary ammonium. ]

  In the black compound represented by the general formula (1) of the present invention, n represents an integer of 2 to 12.

Each M independently represents an alkali metal, an amine, or a quaternary ammonium. Although it does not specifically limit as an alkali metal, For example, lithium, sodium, potassium, etc. are mention | raise | lifted. Examples of amines include, but are not limited to, primary amines such as methylamine, ethylamine, and ethanolamine, secondary amines such as dimethylamine and diethylamine, and tertiary amines such as trimethylamine, triethylamine, and triethanolamine. It is done. By introducing quaternary ammonium into M to obtain a quaternary ammonium salt of sulfonic acid, the solubility of the compound in the ink is increased and the storage stability of the ink is improved. Furthermore, gas resistance such as ozone is improved. Of the plurality of M, at least one is quaternary ammonium, more preferably two or more are quaternary ammonium, more preferably three or more are quaternary ammonium salts, most preferably All M are quaternary ammonium.
The quaternary ammonium is not particularly limited, but preferably has a total carbon number of 4 or more. For example, tetramethylammonium, tetraethylammonium, tetrapropylammonium, tetrabutylammonium, tetra-n-hexyl. Examples include ammonium, tetra-n-octylammonium, benzyltrimethylammonium, benzyltriethylammonium, phenyltrimethylammonium, vinyltrimethylammonium, n-hexadecyltrimethylammonium, 3-trichloromethylphenyltrimethylammonium, carboxymethyltrimethylammonium, and the like.
In the production of the black compound of the present invention, although not particularly limited, for example, a dye represented by the following formula (2) is sulfonated and a sulfonic acid part is partially formed with a corresponding quaternary ammonium hydroxide. Alternatively, it can be obtained by using a quaternary ammonium salt as a whole.
The sulfonation method is not particularly limited, but generally, a method of heating in fuming sulfuric acid, a method using sulfur trioxide, a method using chlorosulfuric acid, or the like is used. If necessary, a catalyst such as ammonium sulfate, vanadyl sulfate, or boric acid can be added.

  The ink of the present invention is useful as various inks, particularly as an ink jet recording liquid. The compound can be used as it is when the content of inorganic salts is small, but particularly when used as a recording liquid for an ink jet recording method, the discharge nozzle of the recording apparatus is clogged by inorganic salts contained in the dye. In order to prevent this, it is preferable to carry out purification by, for example, a desalting treatment by ion exchange resin or reverse osmosis membrane (RO membrane) filtration or other desalting treatment methods.

  Other purification methods of the black compound include dissolving the compound in ion-exchanged water and crystallizing it by adding a polar solvent, or discharging the aqueous solution of the black compound into the polar solvent. There is a method of crystallization. By this method, inorganic salts such as KCl, NaCl, Na 2 SO 4 contained in the black compound can be reduced and removed.

  The main components of the ink of the present invention contain the black compound of the present invention, water and, if necessary, an organic solvent. The black compound of this invention may be used independently and may be used in mixture of 2 or more types. The amount used depends on the purpose, purpose, type of dye, ink composition, ink printing density, and clogging, but the black compound is preferably 0.5 to 20% based on the entire aqueous ink. Especially preferably, it is 1 to 10%, and the organic solvent is preferably in the range of 0 to 80%.

  In addition, in order to adjust the color of the ink and improve other properties, other dyes, or those obtained by treating known dyes and pigments into emulsion or finely dispersed state to such an extent that the ink properties are not impaired It doesn't matter.

The ink of the present invention is a dissolution type water-based ink, and water is used as a main solvent component, but it is mixed with a water-soluble organic solvent for the purpose of preventing the ink from drying and improving the solubility of the black compound. It can also be used. Examples of water-soluble organic solvents include ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, 1,3-propanediol, glycerin, thioglycol and other polyhydric alcohols, ethylene glycol monoethyl ether, ethylene Glycol monobutyl ether, diethylene glycol monobutyl ether, dipropylene glycol monoethyl ether, polyhydric alcohol ethers such as triethylene glycol monomethyl ether, ketones such as acetone and methyl ethyl ketone, N, N-dimethylformamide, N, N-diethylformamide, Amides such as N, N-dimethylacetamide, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-vinyl-2 Nitrogen-containing compounds such as pyrrolidone and 1,3-dimethyl-2-imidazolidinone, ethers such as tetrahydrofuran and dioxane, alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-butanol Etc. These water-soluble organic solvents may be used alone or in combination of two or more, and the content is preferably used in the range of 5 to 50%.
The pH of the ink is preferably 7 or more in order to improve the storage stability of the ink and the water resistance by changing the viscosity of the ink. In order to further improve the water resistance, it is preferable to use an amine such as ammonia and a hydroxyamine such as triethanolamine in combination. The content is preferably about 0.001 to 10% with respect to the ink.

  Further, urea, thiourea, biuret, semicarbazide, and derivatives thereof may be used in combination with the ink containing the black compound of the present invention. The content is preferably about 0.1 to 15% with respect to the ink.

  The ink of the present invention composed of the above composition is an ink for a writing instrument or an ink for an ink jet recording system, and has recording characteristics, storage stability, fixability to a recording material, sharpness of a recorded image, light resistance, resistance to light. It is excellent in ozone and moisture resistance.

When the ink of the present invention is output by an ink jet printer, the type of the printer head is not limited, and can be applied to all printer heads such as piezo type, thermal type, continuous type, and electrostatic type. The print media can be any media such as plain paper, photo-only paper, matte paper, etc., but a particularly preferred print medium is photo-only paper.

  In addition, various conventionally used additives can be added to the ink of the present invention as necessary. For example, UV absorbers, antioxidants, chelating agents, water-soluble polymers, masking agents, fungicides, preservatives, viscosity modifiers, surfactants, surface tension regulators, pH regulators, specific resistance regulators , Additives such as near infrared absorbers and penetrants.

  In the ink of the present invention, the black compound of the present invention is dissolved together with water, an organic solvent, and, if necessary, the additives mentioned above, and filtered through a micropore filter such as a membrane filter in order to remove insoluble matters. It is manufactured by. The ink thus produced is particularly useful as a recording liquid for an ink jet recording system, but is also used as ink for writing instruments such as ballpoint pens, felt pens, and fountain pens.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. In addition, "part" in an Example shows a weight part.

[Synthesis Example 1]
C. 30% fuming sulfuric acid (200 g) containing, as a main component, a compound having the structural formula represented by the following (3): I. Vat black 9 (30 g) was added and reacted at 120 ° C. for 10 hours. The reaction mixture was drained into ice water (750 g). Sodium chloride (200 g) was added to the mixed solution to salt out black crystals, which were filtered off under reduced pressure. The obtained black crystals were washed with a 20% aqueous sodium chloride solution and a small amount of distilled water and dried to obtain a compound (41 g) containing a sulfonic acid form (4).

[Synthesis Example 2]
The sulfonic acid compound (4) (5 g) obtained in Synthesis Example 1 was discharged into distilled water (45 g). While stirring the solution, 10% tetramethylammonium hydroxide was added until the pH of the solution was 10. Acetone (300 g) was added to the solution and the precipitated crystals were separated by filtration and further washed with 90% acetone. The obtained crystal was dried to obtain a black compound (3 g) containing a quaternary ammonium salt (5).

[Synthesis Examples 3 to 6]
The base added in Synthesis Example 2 was changed to tetramethylammonium hydroxide, and the same operation as in Synthesis Example 2 was performed using the bases shown in Table 1 below to obtain the corresponding quaternary ammonium salt.

[Comparative Synthesis Examples 1 to 3]
The base added in Synthesis Example 2 was changed to tetramethylammonium hydroxide, and the same operation as in Synthesis Example 2 was performed using the bases shown in Table 2 below to obtain the corresponding alkali metal salts.

[Adjustment and evaluation of ink]
<Preparation of ink>
The black compound was mixed and dissolved in the composition shown below, and then filtered through a Teflon (registered trademark) filter having a pore diameter of 0.8 microns to prepare an ink.
<Ink composition>
Black compound (5) of Synthesis Example 2 5 parts Glycerin 5 parts
Diethylene glycol 5 parts N-methyl-2-pyrrolidone 5 parts Triethylene glycol monobutyl ether 10 parts Ion-exchanged water 70 parts <Evaluation of characteristics>
Using the ink prepared above, the ink cartridge for a piezo type ink jet printer is filled, and printing and image recording are performed on the ink jet exclusive paper (PM photo paper manufactured by Seiko Epson Corporation) with the same type printer. A test was conducted. as a result,
(A) Moisture resistance evaluation: ◎, (B) Light resistance evaluation: 、, (C) Oxidation gas resistance evaluation: ◎, (D) Ink storage stability evaluation: ◎.

The evaluation criteria for each test item are as follows.
Image formation: Printing and image recording were performed on special paper using a piezo inkjet printer.
(A) Evaluation of moisture resistance: The plain paper on which the test image was recorded was left to stand for 1 week under the conditions of 50 ° C. and 85% humidity, and the moisture resistance of the recorded image was evaluated visually.
Evaluation criteria: No change in image;
Slight bleeding at the edge of the image, but no problem level; ○
Bleeding is observed at the edge of the image;
Bleeding is spreading from the edge of the image; ×
(B) Light resistance evaluation: After irradiation for 100 hours using a xenon fade meter (manufactured by Suga Test Instruments Co., Ltd.), print density (OD value) before and after irradiation is measured using a reflection densitometer (manufactured by Macbeth). The OD1 value was calculated by the following formula, and the light resistance was evaluated.
OD1 value (%) = (OD value after irradiation) / (OD value before irradiation) × 100
Evaluation criteria: OD1 value is 100 to 80% or more;
OD1 value is less than 80% to 70%;
OD1 value is less than 70% to 50%;
OD1 value is less than 50%;
(C) Evaluation of oxidation gas resistance: The sample was left for 2 hours in a nitrogen stream adjusted to an ozone concentration of 100 ppm, and the printing density (OD value) before and after the test was measured using a reflection densitometer (Macbeth). The OD2 value was calculated by the equation and the oxidation gas resistance was evaluated.
OD2 value (%) = (OD value after test) / (OD value before test) × 100
Evaluation criteria: OD2 value is 100 to 80% or more;
OD2 value is less than 80% to 70%;
OD2 value is less than 70% to 50%;
OD2 value is less than 50%;
(D) Storage stability evaluation of ink (precipitate): After the ink was stored at 40 ° C. for 1 month, the presence or absence of insoluble matter was visually observed.
Evaluation criteria: No insoluble matter; ○
Slightly suspended matter can be seen: △
Insoluble matter; ×

[Examples 2 to 5]
Table 3 shows the evaluation of ink prepared by the same method as in Example 1 except that the compounds of Synthesis Examples 3 to 6 were used instead of the black compound (5).

[Examples 6 to 10]
[Adjustment and evaluation of ink]
<Preparation of ink>
A black compound was mixed and dissolved in the composition shown below, and then filtered through a Teflon (registered trademark) filter having a pore diameter of 0.8 microns to prepare an ink.
<Ink composition>
Black compound 5 parts Triethylene glycol mono-n-butyl ether 10 parts Diethylene glycol 4 parts Glycerin 10 parts Triethanolamine 1 part Urea 6 parts Acetylenol E-H 1 part Ion-exchanged water 63 parts

<Evaluation of characteristics>
Using the ink prepared above, the ink cartridge for the thermal ink jet printer is filled, and printing and image recording are performed on the ink jet exclusive paper (Professional Photo Paper PR-101 manufactured by Canon Inc.) using the same printer. The evaluation results are shown in Table-4.

[Comparative Examples 1-3]
Ink was prepared in the same manner as in Example 1 except that the alkali metal salt synthesized in Comparative Synthesis Examples 1 to 3 was used instead of the quaternary ammonium salt. None of the alkali metal salts provided sufficient solubility, and the Teflon (registered trademark) filter of 0.8 micron was poor. The obtained ink was evaluated in the same manner as in Example 1. As a result, the gas resistance and storage stability were insufficient. The evaluation results are shown in Table-5.

[Comparative Example 4]
The ink was prepared and evaluated in the same manner as in Example 1 except that disazo black dye, CI Acid Black 1 was used instead of the black compound in Synthesis Example 2, and (A) moisture resistance evaluation; Δ, (B ) Light resistance evaluation; x, (C) gas resistance evaluation; x, (D) storage stability evaluation;

  The black compound of the present invention and the ink using the same are excellent in moisture resistance, light resistance and gas resistance and have high ink storage stability, and are particularly useful for ink jet ink applications.

Claims (2)

A black compound represented by the following general formula (1).

[Wherein n represents an integer of 2 to 12. Each M independently represents an alkali metal, an amine, or quaternary ammonium, and at least one of the plurality of M is quaternary ammonium. ] An ink comprising at least one black compound according to claim 1.