JPS6339028B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an aqueous ink for inkjet printers that has excellent dissolution stability. The inkjet recording method prints on the recording medium by ejecting ink droplets at high speed from a nozzle with a small orifice diameter of 10 to 400μ, making it possible to record with low noise and high resolution, and even print in color. is also easy. Despite having these advantages, this recording method uses a small nozzle diameter, which tends to cause clogging, resulting in significantly lower reliability. Nozzle clogging is particularly likely to occur when the water in the ink evaporates, and it is often difficult to prevent it even though drying can be prevented by adding a wetting agent such as a polyhydric alcohol. In general, it is possible to prevent clogging to some extent by sufficiently preventing ink from drying by installing a lid on the end of the nozzle when the printer is stopped, but if the printer has not been used for a long time or the environmental temperature is low, High temperatures of 40℃ or higher,
When placed in a place at a low temperature of 0.degree. C. or lower, problems such as clogging may occur in about 1 to 2 weeks even though there is almost no evaporation of water. From the perspective that the cause of clogging is the lack of solubility of dyes in water, the addition of dye solubilizers or dye dissolution aids is generally proposed as a measure to prevent clogging. Glycol derivatives in which the hydroxyl group of ethylene glycol is alkyl etherified, pyrrolidone and its derivatives, tetrahydrofurfural alcohol, 4-methoxy-4-methylpentan-2one, ethylene oxide adduct of p-toluenesulfonamide, thiodiethanol, alkanolamine, Although various other additives are known, the dissolution stability of the dye by adding them is not necessarily sufficient. Therefore, the object of the present invention is to reduce the evaporation of water in the ink,
An object of the present invention is to provide an inkjet recording ink that prevents nozzle clogging caused by changes in environmental temperature. The present invention provides a water-based ink for inkjet printers, which contains water, a water-soluble dye, and a water-soluble phthalimide derivative obtained by adding ethylene oxide or ethylene oxide and propylene oxide to phthalimide. be. The phthalimide derivative used in the present invention has the general formula In the formula, m is 0 or an integer of 1 to 2, and n is an integer of 1 to 13. Water-soluble phthalimide derivatives represented by are suitable. The foaming property of the derivative of formula (1) tends to increase as n increases, so when n is 5 or more, m is more preferably 1 to 3. On the other hand, n
Since water solubility tends to weaken as the value decreases, it is more preferable that m is 0 or 1 when n is 5 or less. Optimally, m is 1 and n is 5 to 9.
In this case, the ink has the best stability and its foaming property is very weak, so stable ink jetting is possible. Furthermore, it is possible to shorten the printing drying time, and at the same time, it is possible to provide excellent quality printing with little bleeding. The content of the above-mentioned phthalimide derivative can be 0.01 to 20% by weight of the total amount of ink, depending on the type of dye used and the viscosity of the ink suitable for the recording head, but 0.1 to 5% by weight is usually preferred. be. Examples of the water-soluble dye used in the present invention include various water-soluble direct dyes, acid dyes, basic dyes, disperse dyes, and reactive dyes. Next, a specific example will be given. CI Direct Yellow 8, 12, 26, 28, 44,
50, 86, 98, 142; CI acid yellow 7, 19, 23, 38, 44,
61, 110, 141, 193; CI basic yellow 4, 11, 13, 15, 21,
28, 32, 51; CI Disperse Yellow 5, 51, 60, 64,
76, 88, 186, 192; CI reactive yellow 13, 14, 75, 79,
114, 115, 116; CI Direct Red 4, 9, 13, 23, 31,
79, 81, 83, 240, 241; CI Assured Dred 1, 6, 14, 35, 52, 88,
111, 131, 249, 274; CI basics 14, 15, 18, 27, 46:
1, 39: 1, 82, 95; CI dispersion thread 43, 54, 60, 65, 73,
88, 92, 135, 189, 190, 191, 205, 288,
296; CI reactive bullets 22, 23, 108, 109,
110, 111, 114; CI Direct Blue 1, 2, 15, 22, 25,
71, 86, 90, 98, 192; CI acid blue 7, 40, 62, 78, 83, 92,
112, 126, 129; CI basic blue 1, 3, 5, 7, 9,
24, 25, 26, 28, 47, 129, 135, 137; CI Disperse Blue 26, 54, 56, 60, 73,
81, 139, 143, 257, 301; CI Reactive Blue 5, 15, 19, 21, 49,
100, 147, 148; CI Direct Blue 17, 19, 22, 32, 38,
51, 62, 107, 112, 132, 154; CI Assisted Blue 1, 2, 24, 31, 52, 58,
60, 107, 109, 155; CI Basic Black 2; CI Disperse Black 1; CI Reactive Black 5, etc., but the dyes are not necessarily limited to these dyes. These dyes can be used alone or in a mixture of two or more. In addition to the above-mentioned components, the ink according to the present invention may further contain a wetting agent, a PH regulator, a sequestering agent, a fungicide, another dye dissolution aid, a water-soluble binder resin, etc. as necessary. Can be done. Wetting agents that can be used as necessary in the present invention include polyhydric alcohols such as ethylene glycol, diethylene glycol, glycerin, triethylene glycol, tetraethylene glycol, polyethylene glycol #200, 300, 400, 600, and polypropylene glycol. Pyrolidones such as N-vinylpyrrolidone, N-methylpyrrolidone, β-hydroxyethylpyrrolidone; monoethanolamine, diethanolamine, triethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, N-
Methyldiethanolamine, N-ethyldiethanolamine, N-propyldiethanolamine,
Examples include amino alcohols such as N-butyldiethanolamine; amides such as formamide, N,N-dimethylformamide, and N,N-dimethylacetamide. Examples of PH regulators that can be used as needed in the present invention include sodium carbonate, sodium borate, sodium bicarbonate, and sodium acetate; sequestering agents include EDTA, sodium salt or potassium salt of glyconic acid; and antioxidants. Examples include sodium tehydroate, 2,4,6-trichlorophenol, dioxin, and sodium omazine. Next, the present invention will be specifically explained by comparing Examples and Comparative Examples. Examples 1 to 3 The components of each formulation shown in Table 1 were mixed, thoroughly stirred, and then filtered through a 1.5μ Pall filter to prepare inks. The dissolution stability and rejetting properties of each ink were tested in the following manner, and the results are listed in Table 1. Dissolution stability - The ink was sealed in a Pyrex test tube and left at temperatures of 5°C and 50°C for 14 days, and then the presence or absence of precipitates was examined. The precipitate was expressed as follows. ◎ No precipitates at all 〇 〃 Hardly any △ 〃 A small amount × 〃 A large amount Re-jetting property - Pour ink into the ink tank of an inkjet device with a glass nozzle with a hole diameter of 30μ, eject it once, then stop the ejection, In the same state, 3
After being left at room temperature for 30 days, 7 days, 14 days, 30 days, 60 days, and 90 days, the spray was sprayed again and the nozzle was checked for clogging.
The maximum number of days it can be left unused for re-injection without clogging is displayed. In addition, the phthalimide derivative (a) in Table 1 is Phthalimide derivative (b) is Phthalimide derivative (c) is represent

[Table] Examples 4 to 8 Examples 1 to 3 from the ingredients of the composition listed in Table 2
Inks were prepared in the same manner as described above, and the same tests were conducted for each ink.

【table】

[Table] From the comparison between the above-mentioned Examples and Comparative Examples, the ink to which the phthalimide derivative according to the present invention is added is compared with the ink without the additive and the ink to which a conventionally known dye solubilizer is added. It will be appreciated that this provides surprisingly good results in dye dissolution stability and rejetability (anti-clogging properties).

Claims (1)

[Scope of Claims] 1. A water-based ink for inkjet printers, characterized in that it contains a water-soluble phthalimide derivative obtained by adding ethylene oxide or ethylene oxide and propylene oxide to phthalimide. 2 Phthalimide derivatives have the general formula In the formula, m is 0 or an integer of 1 to 2, and n is an integer of 1 to 13. The ink according to claim 1, which is a compound represented by: 3 The phthalimide derivative has m in the above general formula of 1,
The ink according to claim 2, wherein n is an integer of 5 to 9.