JPH054425B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD The present invention relates to a recording ink for a cyan inkjet. Prior Art Conventionally, recording inks for inkjet containing water-soluble dyes such as metal phthalocyanine sulfonates have been known (Japanese Unexamined Patent Application Publication No. 1983-1999).
145771, Japanese Patent Application Laid-open No. 144064/1983). However, in general, metal phthalocyanine sulfonic acid dyes, especially copper phthalocyanine sulfonic acid dyes which have excellent color tone as cyan dyes, tend to associate in water or water/wetting agent systems.
When this ink was used as a cyan inkjet ink, there were problems such as clogging of nozzles. Therefore, in inkjet recording using cyan dye, it is necessary to take precautions to prevent the formation of precipitates and nozzle clogging, especially in order to perform good recording over a long period of time. Purpose The present invention was made in view of the above problems, and its purpose is to solve the cause of clogging when a copper phthalocyanine sulfonic acid dye, which has an excellent color tone as a cyan dye, is used as a recording ink for an inkjet. It is an object of the present invention to provide a recording ink for a cyan inkjet which has excellent overall properties such as water resistance, light resistance, and ejection stability. More specifically, the present invention does not cause clogging of the discharge nozzle, deterioration or precipitation during storage. It has good jetting stability and jetting response, and even if it is used continuously for long periods of time, there is little change in the physical properties of the ink, and the recorded images have excellent weather resistance, good color reproducibility, and no image blurring. An object of the present invention is to provide a recording ink for a cyan inkjet that has a high density and is clear. Structure In the case of a phthalocyanine sulfonic acid dye, the present invention provides that when a phthalocyanine dye whose central metal is copper coexists with a phthalocyanine dye whose central metal is cobalt, nickel, or zinc, compared to when the copper phthalocyanine dye itself is used alone. This is based on the knowledge that it is difficult to associate even in water or in a water/wetting agent system, and therefore does not cause clogging of the discharge nozzle and has specific effects such as stabilizing the direction of jetting. That is, according to the present invention, (1) the water-soluble dye includes (A) a copper phthalocyanine sulfonic acid dye represented by the following structural formula (); (B) a metal phthalocyanine sulfonic acid dye represented by the following structural formula (); And the ratio of (A):(B) used is 1:0.001 by weight
There is provided a recording ink for a cyan inkjet, characterized in that the ratio is 1:1. As described above, the cyan-colored inkjet recording ink of the present invention contains a phthalocyanine sulfonic acid dye whose central metal represented by the above structural formula () is copper, and a phthalocyanine sulfonic acid dye whose central metal is represented by the above structural formula () cobalt, nickel, or Contains phthalocyanine sulfonic acid dye, which is zinc, in a specific proportion, so it does not clog the discharge nozzle, cause deterioration or precipitation during storage, has good jetting stability and jetting response, and can be used continuously for a long time. Even after repeated use, there is little change in the physical properties of the ink, and the recorded images have excellent weather resistance, good color reproducibility, little image blurring, and a clear cyan color with high density. It has the following advantages. In the present invention, the main dye (A) is a tri- and/or tetrasulfonate of copper phthalocyanine (in the case of n=3 to 4 in the above structural formula ())
On the other hand, a combination in which the subdye (B) is a tri- and/or tetrasulfonate of nickel phthalocyanine (in the above structural formula, when X is nickel and n=3 to 4) is particularly effective. In the present invention, it is also necessary that the weight ratio of the main dye (A) to the sub-dye (B) be in the range of 1:0.001 to 1:1. If the usage ratio of the main dye (A) and the sub-dye (B) is outside this range, it is not appropriate because a clear cyan color cannot be obtained and clogging is likely to occur. As is clear from the Examples and Comparative Examples described later, when the copper phthalocyanine sulfonic acid dye represented by the structural formula () is used alone, or when the metal phthalocyanine sulfonic acid dye represented by the structural formula () is used alone, When used in the recording liquid, these dyes aggregate in the recording liquid, resulting in the formation of precipitates that can clog the nozzle, or cause significant changes in the jetting direction, causing the dye to be ejected for a long period of time. The effects of the present invention, such as no nozzle clogging and excellent injection stability, cannot be achieved. Furthermore, in the practice of the present invention, when metal is used for members that come into contact with recording ink, it is important to adjust the pH of the ink to a range of 9.0 to 11.0 in order to prevent oxidation. The cyan inkjet recording ink of the present invention mainly contains water, a water-soluble organic solvent, a wetting agent, and an antiseptic and antifungal agent in addition to the water-soluble dye. A regulator, a PH regulator, a rust preventive, a viscosity regulator, etc. may be added. Preferred water-soluble organic solvents include polyhydric alcohols and alkyl ethers of polyhydric alcohols, such as diethylene glycol, glycerin, ethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol, polypropylene glycol, ethylene glycol monoether ether, and ethylene glycol monobutyl ether. , diethylene glycol monomethyl ether,
Examples include diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, and triethylene glycol monoethyl ether. Wetting agents are added to prevent the ink from drying out and clogging the nozzle when ink jetting is stopped, and include glycerin, diethylene glycol, ethylene glycol, triethylene glycol, polypropylene glycol, and polyethylene. Fatty polyhydric alcohols such as glycols and alkyl ether derivatives of these polyhydric alcohols can be used. Water-soluble antiseptic mold agents include sodium 2,2-dimethyl-6-acetoxy-dioxane-1,3-dehydroacetate, p-hydroxybenzoic acid butyl ester, potassium sorbate, sodium 2-pyridinethiol-1-oxide, Examples include anionic surfactants. Commercially available products of this type include the product names Deltop 33 (manufactured by Takeda Pharmaceutical Co., Ltd.) and Biocide 830 (manufactured by Taisho Corporation). PH regulators that can be suitably used in the present invention include those that do not have an adverse effect on the ink to be formulated;
Any substance can be used as long as it can control the pH of the ink within the range of 9.0 to 11.0. For example,
Examples include amines such as diethanolamine and triethanolamine, hydroxides of alkali metal elements such as sodium hydroxide and potassium hydroxide, and ammonium hydroxide. In addition, substances that can be added to the cyan inkjet recording ink of the present invention include those that have a specific electrical conductivity of 1 mΩ/cm (at 25°C).
Specific electrical conductivity regulators, chelating reagents, and rust preventive agents can be used to achieve the above properties. Specific electrical conductivity regulators include, for example, inorganic salts such as potassium chloride, ammonium chloride, sodium sulfate, and sodium carbonate, water-soluble amines such as triethanolamine, and quaternary ammonium salts such as tetramethylammonium bromide. be. Examples of the chelating reagent include sodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium laumyldiacetate. Examples of rust preventives include acidic sulfites, sodium thiosulfate, ammonium diisopropylammonium nitrite thioglycolate, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite. Examples The present invention will be explained in more detail by the following examples, but the invention is not limited thereto. In the examples, percentages are given by weight. Example 1 Copper phthalocyanine tetrasulfonic acid sodium salt 3.0% Nickel phthalocyanine tetrasulfonic acid sodium salt 0.5〃 Diethylene glycol 15.0〃 Glycerin 5.0〃 Water-soluble preservative mold agent (manufactured by Takeda Pharmaceutical Co., Ltd., Deltop 33) 0.2〃 Ion exchange water 76.3〃 Above After mixing and stirring the composition (70℃), the PH
Adjust the overall pH to 10.0 with 13.0 NaOH solution and adjust the pore size.
An ink was prepared by filtering twice through a 0.2 μm filter. Next, inks of Examples 2 to 5 and Comparative Examples 1 to 2 were created in the same manner as in Example 1 using the following formulations. Example 2 Copper phthalocyanine tetrasulfonic acid lithium salt
2.5% Nickel phthalocyanine trisulfonic acid lithium salt 0.5〃 Diethylene glycol 15.0〃 Glycerin 5.0〃 Hokuside LX-2 (Hokuko Chemical) 0.2〃 Ion exchange water 77.8〃 Example 3 Copper phthalocyanine tetrasulfonic acid sodium salt 1.05% Cobalt phthalocyanine tetrasulfonic acid sodium salt Salt 1.5〃 Diethylene glycol 15.0〃 Glycerin 5.0〃 Deltop 33 (Takeda Pharmaceutical) 0.2〃 Ion exchange water 76.8〃 Example 4 Copper phthalocyanine tetrasulfonic acid sodium salt 3.0% Nickel phthalocyanine tetrasulfonic acid sodium salt 0.1〃 Diethylene glycol 15.0〃 Glycerol Serin 5.0〃 Deltop 33 (Takeda Pharmaceutical) 0.2〃 Ion exchange water 76.7〃 Example 5 Copper phthalocyanine disulfonic acid lithium salt
3.0% Nickel phthalocyanine tetrasulfonic acid sodium salt 0.5〃 Diethylene glycol 15.0〃 Glycerin 5.0〃 Deltop 33 (Takeda Pharmaceutical) 0.2〃 Ion exchange water 76.3〃 Comparative example 1 Copper phthalocyanine tetrasulfonic acid sodium salt 3.5% Diethylene glycol 15.0〃 Glycerin 5 .0〃 Hokuside LX -2 (Hokuko Chemical) 0.2〃 Ion exchange water 76.3〃 Comparative example 2 Zinc phthalocyanine trisulfonic acid lithium salt
3.0% Diethylene glycol 15.0 Glycerin 5.0 Hokuside LX-2 (Hokuko Chemical) 0.2 Ion exchange water 76.8 Next, various tests were conducted using the various inks obtained above as follows. 1 Image sharpness and image drying properties: Inkjet recording was performed from a 30 μm inner diameter nozzle on high-quality Shihan paper at a particle generation frequency of 100 KHz, and the sharpness of the image was determined. was clear, but the inks of Comparative Examples 1 and 2 were slightly unclear. In addition, the drying time of the recorded materials in Examples 1 to 6 was within 10 seconds at room temperature and normal pressure, but in Comparative Examples 1 to 6, it was within 10 seconds.
2 took about 15 seconds. 2. Storage: The ink is sealed in a glass container and stored at -20°C for 1 month, at 4°C for 1 month, at 20°C for 1 year, and at 90°C.
After storing each sample at ℃ for one week, the degree of ink precipitation and the physical properties and color tone of the ink were determined.
In all of the inks of Examples 1 to 6, no precipitates or changes in the physical properties or color tone of the ink were observed, but in the case of Comparative Examples 1 to 2, the formation of precipitates and changes in the color tone of the ink were observed. It was done. 3. Jetting stability: When the jet recording described in (1) above was performed continuously for 1000 hours, the jets of Examples 1 to 6 were able to achieve stable recording without clogging the nozzles or changing the jetting direction. However, in Comparative Examples 1 and 2, clogging of the nozzles and changes in the spray direction were sometimes observed, making stable recording difficult. 4 Injection response: After recording the jet according to (1) above,
1 month at normal temperature and humidity and 1 month at 40℃~30℃RH
After each week, the jet recording in (1) was performed again, and the presence or absence of normal printing, the presence or absence of clogging, and the presence or absence of a change in direction were determined. The results are shown in Table 1. Please note that the specific measurement method is as follows:
A device with 10 nozzles was used, and the number of nozzles printing normally, the number of clogged nozzles, and the number of nozzles whose direction had changed were counted.

Table 2 shows the color tones of images recorded using the various inks obtained above.

【table】

[Table] Effects According to the recording ink for cyan inkjet of the present invention constructed as described above, a recorded image having a clear cyan color can be obtained, and this recorded image has good water resistance, light resistance, etc. Moreover, the recording ink of the present invention shows no clogging of the ejection nozzle or change in the ejection direction of the recording liquid even after long-term use, and has excellent ejection stability.

Claims (1)

[Claims] 1. As a water-soluble dye (A) a copper phthalocyanine sulfonic acid dye represented by the following structural formula (). (B) Contains a metal phthalocyanine sulfonic acid dye represented by the following structural formula (), and the ratio of (A):(B) used is 1:0.001 or more by weight.
A cyan inkjet recording ink characterized by a 1:1 ratio.