JPS6214189B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to aqueous jet ink compositions. More specifically, the present invention relates to an aqueous jet ink composition that can be used for a long time without clogging the nozzle of a jet printer and has a short apparent drying time. By the way, the basic printing principles of known inkjet recording methods include electrostatic attraction type, intermittent ejection type using pulse pressure, and continuous ejection using continuous pressure of several atmospheres, from the viewpoint of the method of ejecting ink droplets from the nozzle. There are methods such as types. In addition, from the viewpoint of how to control ink droplets, there are charge deflection type, electric field deflection type, and non-charge type (on-demand type). In practice, it seems that various combinations of the above-mentioned ejection methods and ink droplet control methods have been proposed and implemented, each with its own unique recording methods. However, in any ink jet method, ink must be continuously and stably ejected as uniform ink droplets from fine nozzles. Therefore, the basic problem to be solved in inkjet printers is to completely prevent clogging of this nozzle section and ensure continuous and stable generation of ink particles for a long period of time. Another important point is that stable ink particles can be created again after a temporary pause. Naturally, fine nozzles can become clogged even by the adhesion of even a small amount of solvent-insoluble solids. Furthermore, even if solid matter adheres to a part of the nozzle, the direction of ink jetting changes. Therefore, in order to eject continuous and stable ink particles, not only the viscosity and surface tension of the ink composition must be appropriate;
It is also necessary to completely remove the solvent-insoluble solid content in the ink composition and to prevent the solvent-insoluble solid content from being generated over time. By the way, water-soluble dyes are usually used for coloring water-based jet ink compositions in order to prevent the formation of solvent-insoluble solids. However, in recent years, there has been an extremely strong demand for inks with high light resistance or high clarity, and with this, it has become necessary to expand the types of dyes used and to mix multiple dyes. Conventionally, polyhydric alcohols and the like have been commonly used as water-soluble wetting agents, but these wetting agents are selective in the solubility of dyes, so some dyes cannot be made into inks, and multiple dyes cannot be combined. When the dye is used to adjust the chromaticity, it does not have uniform solubility for all the dyes used, so nozzle clogging often occurs when the nozzle portion is dried. Furthermore, as there has recently been a demand for faster processing of inkjet recording paper, etc. that has been printed with ink, it has become necessary to shorten the apparent drying time (touch drying time) of the ink. . Conventional wetting agents such as polyhydric alcohol have a slow apparent drying time, and especially when recording with a mixture of two or more color inks in recent color printing, the drying time to the touch is slow due to the slow penetration rate into the paper. The disadvantage was that it became significantly longer. The purpose of the present invention is to improve the drawbacks of the prior art as described above, and to expand the scope of use of dyes (there is no selectivity in dissolving dyes), and to create an aqueous jet ink composition that does not clog nozzles and has a short drying time. It is about providing something. That is, the present invention provides an aqueous jet ink composition containing a water-soluble dye, a wetting agent, and water as main components, in which at least N.N-bis[polyoxyethylene] _o - is used as the wetting agent.
p-Toluenesulfonic acid amide (however, n=1~
The present invention relates to a jet ink composition characterized by containing 4). The water-soluble dyes used in the present invention include acid dyes,
Any water-soluble basic dye, direct dye, etc. can be used. For example CIDirect Blue 236, CIDirect
Blue203, CIDirect Blue202, CIDirect
Blue15, CIAcid Blue7, CIAcid Blue9, CI
DirectBlue199, CIDirect Yellow144, CI
Direct Yellow100, CI Direct Yellow86, CI
Direct Yellow50, CIAcid Yellow1, CIAcid
Yellow23, CIAcid Green5, CIBasic
Violet39, CIDirect Red23, CIDirect
Red227, CIDirect Red225, CIAcid Red87,
CIAcid Red92, CIAcid Red52, CI
Acid145, CIAcid252, CIBasic Red27, CI
Basic Red46, CIBasic Red12, CIBasic
Red38, CIAcid Red94, CIAcid Red289, C.
I.Direct Black51, CIDirect Black19, CI
Examples include Direct Black 38, which can be used singly or as a mixture of two or more. In the jet ink composition of the present invention, at least N.N-bis[polyoxyethylene] _o -p-toluenesulfonic acid amide is used as a wetting agent. That is, the jet ink composition of the present invention contains N.N-bis[polyoxyethylene] _o -p-toluenesulfonic acid amide as a wetting agent alone or in combination with a conventionally known water-soluble wetting agent. do. In the N·N-bis[polyoxyethylene)-p-toluenesulfonic acid amide used in the present invention, the number of oxyethylene groups is 1 to 4.
However, since it is difficult to extract these as individual products, they are usually used as a mixture. Also, N・N-bis[polyoxyethylene] _o −
When using a mixture of p-toluenesulfonic acid amide and a conventionally known water-soluble wetting agent, the former 1
~99% by weight, the latter 99-1% by weight. Examples of the above-mentioned conventionally known water-soluble wetting agents include the following. Triethylene glycol, diethylene glycol, glycerin, ethylene glycol, polyethylene glycol, propylene glycol, trimethylolpropane, trimethylolethane, neopentyl glycol, tripropylene glycol, trimethylene glycol, 1,3-butanediol, 2,3-butanediol , 1,4-butanediol, 1,5-pentanediol, hexylene glycol, 1,2,6-hexanetriol, 2,5-tetrahydrofurandimethanol,
polyhydric alcohols such as ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, tripropylene glycol methyl ether, and their acetate esters; hydroxypropyl cellulose, carboxymethyl cellulose, hydroxy Cellulose (cellulose derivatives) such as ethylcellulose and hydroxymethylcellulose; Amines such as permethylated tetraethylenepentamine, hydroxyalkylformamide, and nitrobenzylamine; Polysaccharides such as sorbitate, mannitrate, gum arabic, and dextrin; N-( Hydroxyalkylformamides in which the alkyl group has 1 to 4 carbon atoms such as 2-hydroxyethyl)formamide; 1,4-di(β-hydroxyethoxy)-
2-butene, 1,4-di-(β-hydroxy-γ
Monoalkenediols such as -chloropropoxy)-2-butene; dimethylmethylphosphonate,
Dialkylphosphonates such as diethyl ethylphosphonate; other polyethyleneimine polymers, 6-methylquinoxaline, N-vinyl-2-
Examples include pyrrolidone oligomers, which can be used singly or as a mixture of two or more. The jet ink composition of the present invention has, for example, the following formulation. Water-soluble dye 0.1-15% by weight,
At least N・N-bis[polyoxyethylene] _o −
1-40% by weight wetting agent containing p-toluenesulfonic acid amide, balance water. The aqueous jet ink composition of the present invention as described above preferably has a viscosity of 1.2 to 30 centipoise and a nonvolatile content of about 50% by weight or less from the practical viewpoint of use in an inkjet system. The aqueous jet ink composition of the present invention may further contain a water-soluble solvent, such as dioxane, acetone, diacetone alcohol, alkyl alcohol having 1 to 3 carbon atoms, dimethylformamide, dimethyl sulfoxide, N -Methyl-
You may use 1 type, or 2 or more types, such as 2-pyrrolidone. Furthermore, if necessary, a viscosity modifier such as polyvinyl alcohol; sodium dehydroacetate, 1.2
- amine salt of benzisothiazolin-3-one,
Antifungal agents and preservatives such as 6-acetoxy-2,4-dimethyl-m-dioxane; sodium sulfite,
Oxygen absorbers such as sodium hydrogen sulfite and other various additives can be added and mixed in small amounts. The aqueous jet ink composition of the present invention can be obtained by stirring and mixing the water-soluble dye, wetting agent, and other additives as necessary with water. After mixing, dust, water-insoluble matters, etc. are removed as necessary. It can be obtained as a product by filtration. The aqueous jet ink composition of the present invention thus obtained allows the use of dyes that conventionally could not be made into inks due to poor dissolution stability, does not cause nozzle clogging when the nozzle portion dries, and has a short drying time to the touch. Because it has the excellent feature of being fast, it has extremely high practical value industrially. Hereinafter, the details of the present invention will be explained with reference to Examples. Example Ink raw materials were stirred and mixed for 0.5 hours or more at various ratios shown in Tables 1 and 2 below,
Each raw material was dissolved in water. Then, it was pressurized using a 1.2μ membrane filter manufactured by Millipore Co., Ltd.
After obtaining the aqueous jet ink composition of the present invention, the ink was subjected to a dissolution stability test. In addition, the resulting aqueous jet ink compositions were recorded on paper using a piezo pressurized inkjet printer, and the light fastness and sharpness of the recorded matter were compared, as well as a comparative test for nozzle clogging. The results are shown in Tables 1 and 2. Furthermore, the drying time to the touch of the single color ink and the drying time to the touch of the mixed color ink were measured, and the results are shown in Table 4. Each test was conducted and judged as follows. Nozzle clogging: The nozzle used for recording was kept at room temperature and humidity 30
After being left at ~70% for one week, it was again subjected to recording. ◎ No nozzle clogging, × Ink does not eject Dissolution stability: Ink was placed in a sealed plastic container and left at room temperature for 6 months. ◎No precipitation, ×With precipitation Light resistance: Xenon lamp manufactured by Ushio Inc.
The optical densities were compared after 5 hours of irradiation using UXL500LS at an irradiation energy of 230 joules/cm ² ·hr. ◎Clearness of 90% or more compared to the initial value: Comparison with Pantone colors ◎Color mixing to the same degree as Pantone colors: After recording the first single color on the recording paper, immediately record the second single color. That is, the colors are mixed on the recording paper. Comparative Example Using the ink raw materials shown in Table 3, an ink was prepared in the same manner as in the above example, and then subjected to a comparative test.

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[Table] From the above results, it is clear that the aqueous jet ink composition of the present invention can use dyes that conventionally could not be made into inks due to poor dissolution stability, and does not cause nozzle clogging when drying. Furthermore, it has the excellent effect of being quick to dry to the touch.

Claims (1)

[Claims] 1. In an aqueous jet ink composition containing a water-soluble dye, a wetting agent, and water as main components, at least N.N-bis[polyoxyethylene] _{o is} used as a wetting agent.
-p-toluenesulfonic acid amide (however, n=1
A jet ink composition comprising ~4). 2. The jet ink composition according to claim 1, wherein the wetting agent is contained in an amount of 1 to 40% by weight in the ink composition.