JPH0224866B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a new copper phthalocyanine dye and an aqueous ink containing the dye, and particularly provides an aqueous ink with extremely good water resistance for use in inkjet recording. The inkjet recording method is a method in which recording is performed by causing a recording medium liquid called ink to fly as droplets from an ejection port provided in a recording head and adhere to recording paper, and does not require a specific fixing process. First, it has the advantage of generating less noise during recording. Various methods have been proposed for such recording methods. For example, a recording head with a piezo vibrator is given a recording signal, and according to the signal, droplets of the recording medium liquid are generated and recorded, or the recording medium liquid is electrostatically attracted, and the generated droplets are used as the recording signal. A method that performs recording by controlling the electric field according to the current, generates droplets with a controlled amount of charge using a continuous vibration generation method, and flies the droplets between deflection electrodes to which a uniform electric field is applied. Many methods are known, including those for recording. However, no matter which method is used, the ejection orifice of this type of recording device has a small hole (generally about a straight hole).
50 μm) and is prone to clogging due to solids in the ink. Further, even if no clogging occurs, the generation of solid components may affect the stable flight of uniform droplets, and may reduce ejection stability, responsiveness, and continuous recording performance. Alternatively, if the constituent components of the recording liquid medium undergo chemical changes, the physical properties of the recording medium liquid, which were adjusted to the desired values at the time of compounding, deviate from the appropriate range, resulting in problems with ejection stability, responsiveness, continuous recording, etc. There may be adverse effects. The recording medium liquid used for inkjet recording is usually water or an organic solvent in which a dye is dissolved. However, when using an organic solvent, it is necessary to avoid those that are highly volatile, have a bad odor, or are toxic to the human body, so inks that use water as the main solvent are generally preferred. Under these circumstances, it is desired that the coloring material used in inkjet recording be a dye with excellent solubility in water and high tinting power. Generally, ink has three primary colors: yellow, magenta, and cyan, and in some cases, black is added to these four primary colors to obtain various hues. Traditionally, cyan coloring materials include CI Direct Blue 86 (CI74180) (formula [ ] below), CI Acid Blue 249 (CI74220) (formula [ ] below), and CI
Acid Blue 9 (CI42090) (formula [ ] below) is known. CuPc−(SO ₃ Na) ₂ [] CuPc−(SO ₃ Na) ₄ [] Because CI Direct Blue 86 does not have sufficient solubility in water, a solubilizer is added as an auxiliary agent, but it is still difficult to create a completely stable aqueous ink. CI Acid Blue 249 had a lot of sulfonic acid residue, and although its solubility in water was improved, its solubility caused the disadvantage that the water resistance of the ink after recording was poor. Similarly, CI Acid Blue 9 has good solubility, but the water resistance of the ink after recording is poor. As mentioned above, inkjet recording ink has extremely stable solubility to prevent orifice clogging until it is recorded on paper, and after it is recorded on paper, it has water resistance that will not dissolve even if it gets wet with water. It must possess the contradictory characteristics required. The present invention has been made in view of this point. The inventors of the present invention have conducted intensive studies to create a stable ink for cyan inkjet recording, and have found that if the dye represented by the general formula [] is used, storage stability, ejection stability, ejection response, and continuous recording are It has been found that a cyan inkjet recording ink can be obtained which has good water resistance and also has excellent water resistance after being recorded on paper. The present invention is based on the general formula [] (In the formula, CuPc is a copper phthalocyanine residue,
R ₁ is hydrogen, a C _{1-3 alkyl} group or a C _1-3 hydroxyalkyl group, R ₂ is a C _1-4 hydroxyalkyl group, and n represents _a number of _3-4 . ) and an inkjet recording ink containing the same. The copper phthalocyanine dye represented by the general formula [] is produced by chlorosulfonating copper phthalocyanine using a conventional method, for example, using chlorosulfonic acid and thionyl chloride, and then condensing this with a specific amine having substituents R ₁ and R ₂ . can be obtained. When copper phthalocyanine residues are chlorosulfonated, the number of sulfonyl chloride groups introduced can vary from 1 to 4 depending on the chlorosulfonation conditions, but in the case of the present invention, 3 to 4 sulfonyl chloride groups are introduced. The sulfonyl chloride group is susceptible to hydrolysis and becomes a sulfonic acid, which then becomes an alkali metal salt or an amine salt of the sulfonic acid. If large amounts of these salts are mixed in, the water resistance of recorded images will deteriorate, so sulfonyl chloride must be handled with particular care. Preferred amines used in the present invention include monoethanolamine, diethanolamine, monopropanolamine, dipropanolamine,
Examples include 2-aminopropanol, (N-hydroxymethyl)ethanolamine, 2-amino-2-methylpropanol, and N-methylethanolamine. The dye represented by the general formula [] thus obtained dissolves well in water, exhibits a clear cyan color, and exhibits a deep same color on paper. The inkjet recording ink of the present invention is produced by dissolving the dye represented by the general formula [] in water. The content of the dye at this time is 1 to 20% by weight, preferably 2 to 10% by weight, based on the ink composition. Further, polyhydric alcohols, ethers or esters thereof may be added to the ink of the present invention as a solubilizing agent. For example, ethylene glycol,
Examples include diethylene glycol, monomethyl ether, ethyl ether or butyl ether of ethylene glycol, monomethyl ether, ethyl ether or butyl ether of diethylene glycol, acetate, propionate or butyrate of ethylene glycol or diethylene glycol. These solubilizing agents may be added to the ink composition in amounts of 0 to 0.
20% by weight, preferably 1-15% by weight. Other adhesion agents, preservatives, metal corrosion inhibitors, and the like may be appropriately added to the ink of the present invention. The cyan inkjet recording ink of the present invention obtained in this way is extremely stable, has no crystal precipitation, does not clog the orifice, and has good ejection stability, responsiveness, and continuous recording performance. However, once recorded on paper, its water resistance was greatly improved. Next, a method for synthesizing the novel dye of the present invention will be described, but the present invention is not limited thereto. Example 1 (Synthesis of dye (1)) 58 g of copper phthalocyanine was mixed with 210 g of chlorosulfonic acid.
Gradually add and mix to 130g while stirring, then 130g
Heat to ~140°C and stir for 3 hours. The mixture was then cooled to 90°C and 100g of thionyl chloride was added dropwise.
Stir at 90℃ for 3 hours, then cool to 20℃,
Pour into a mixture of 1000 g of ice and 300 g of water to separate the precipitated copper phthalocyanine tetrasulfonyl chloride, and wash with water at 5°C until it becomes almost neutral. The paste of copper phthalocyanine tetrasulfonyl chloride thus obtained was stirred and dispersed in a mixture of 500 g of water and 300 g of ice, and then 30 g of monoethanolamine was added.
was added, then an aqueous sodium carbonate solution was added to adjust the pH to 8-9, and the mixture was stirred for 10 hours. Next, increase the temperature to 1
The temperature was raised to 50° C. in hours, and an aqueous sodium carbonate solution was added to maintain the pH at 8 to 9. When the pH no longer decreased, the product was separated, washed with water, and dried. 100 g of blue-black powder (referred to as dye (1)) was obtained. Examples 2 to 8 (Synthesis of dyes (2) to (8)) In the same manner as in Example 1, 60 g of diethanolamine, 35 g of propanolamine, 70 g of dipropanolamine, 2-
Dyes (2) to (8) were obtained using 35 g of aminopropanol, 37 g of (N-hydroxymethyl)ethanolamine, 40 g of 2-amino-2-methylpropanol, and 35 g of N-methylethanolamine. Table 1 shows the elemental analysis values and maximum absorption wavelengths (aqueous solution) of dyes (1) to (8). The visible absorption waveform of dye (1) is shown in FIG. 1, and the infrared absorption waveform is shown in FIG.

【table】

[Table] Next, examples of the inkjet recording ink of the present invention will be described in detail. Examples 9 to 12, Comparative Examples 1 to 2 Each composition shown in Table 2 was thoroughly mixed and dissolved individually in a container, and after pressurizing and passing through a Teflon filter with a pore size of 1μ, deaeration was performed using a vacuum pump. It was processed into ink. Using the six types of ink obtained, an on-demand recording head (discharge orifice diameter 50μ
m. Piezo vibrator drive voltage 60V, frequency 4KHz)
The following tests (a) to (b) were carried out using a recording device having the following technology, and the results are shown in Table 2. Example 9~
Although good results were obtained in all cases of No. 12, a problem occurred in the comparative example. (b) Long-term storage stability of ink: Even after the ink was sealed in a glass container and stored at -30°C and 60°C for 6 months, no precipitation of insoluble matter was observed in the inks of Examples 9 to 12, and the liquid remained stable. There was no change in physical properties or color tone. The ink of Comparative Example 1 caused precipitation. (b) Ejection stability: Continuous ejection was performed for 24 hours in an atmosphere of room temperature, 5°C, and 40°C, and the inks of Examples 9 to 12 were able to perform stable high-quality recording from beginning to end under all conditions. Ta. The ink of Comparative Example 1 caused clogging of the orifice after 1 hour at 5°C. (c) Ejection response: Intermittent ejection every 2 seconds and ejection after being left for 2 months were investigated, and the inks of Examples 9 to 12 recorded stably and uniformly without clogging the orifice in all cases. Ta. The ink of Comparative Example 1 caused clogging of the orifice. (d) Quality of recorded images: Images recorded using the inks of Examples 9 to 12 had high density and were clear. Furthermore, when immersed in water for 1 minute, there was very little blurring of the image. Images using the ink of Comparative Example 2 were washed out in water and were difficult to read.

[Table] Dye (a): Sodium copper phthalocyanine disulfonate Dye (b): Sodium copper phthalocyanine tetrasulfonate Examples 13 to 16 Same as Example 9, but instead of dye (1), dye (5),
Inks of Examples 13, 14, 15, and 16 were prepared using (6), (7), and (8), and studies (a) to (d) were conducted in the same manner as in Example 9. Excellent results were obtained in all experimental experiments.

[Brief explanation of drawings]

Figure 1 shows the visible absorption waveform of dye 1 (20 mg/water).
FIG. 2 shows the infrared absorption waveform of Dye 1.

Claims (1)

[Claims] 1. A copper phthalocyanine dye represented by the general formula [1]. (In the formula, CuPc is a copper phthalocyanine residue,
_{R 1} is hydrogen, a C _1-3 alkyl group or a C _1-3 hydroxyalkyl group, R ₂ is a C _1-4 hydroxyalkyl group, and _n represents the number of ₄ . ) 2 A water-based ink characterized by containing a copper phthalocyanine dye represented by the general formula [1]. (In the formula, CuPc is a copper phthalocyanine residue,
_{R 1} is hydrogen, a C _1-3 alkyl group or a C _1-3 hydroxyalkyl group, R ₂ is a C _1-4 hydroxyalkyl group, and _n represents the number of ₄ . )