JPS59223766A - Water ink composition for ink jet - Google Patents

Abstract

PURPOSE:To provide the titled ink compsn. which has good characteristics such as low viscosity, high surface tension, high electrical conductivity, etc. and does not cause clogging of printing nozzles even after left to stand over a long period of time, by blending a 1,3-substd. 2-imidazolidinone. CONSTITUTION:1-50wt% at least one compd. selected from among 1,3-substd. 2- imidazolidinone compds. of the formula (wherein R1, R2 are each a 1-4C alkyl, hydroxyalkyl or alkoxy) is incorporated to obtain the desired water ink compsn. for ink jet. The compds. of the formula have an excellent dye dissolving power, a high surface tension and a low viscosity and is low in toxicity and excellent in chemical stability. Examples of said compds. are 1,3-dimethyl-2-imidazolidinone and 1-methyl-3-propyl-2-imidazolidinone.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an inkjet recording ink composition having 1.11
Do J.

The conventional inkjet recording system has been widely applied and developed in recent years because it has a low 15i sound and can easily perform high-speed recording and color printing.

However, several drawbacks have been pointed out in this recording method, and one of the most serious drawbacks is that it prevents the printing nozzle from clogging when left unused for a long period of time. This results in decreased reliability. Although this drawback may be caused by the device itself, it is basically due to the characteristics of the ink that is the printing material.

It goes without saying that water-based inks used in inkjet recording systems need to be improved from the above-mentioned clogging phenomenon, but low viscosity also has a significant impact on jetting conditions, atomization conditions, particle charging conditions, print quality, etc. , high surface tension, high electrical conductivity, and other properties. Furthermore, low toxicity to the human body and chemical inertness to wetted materials are also essential requirements.

However, conventional water-based inks cannot be said to satisfy all of the above-mentioned required characteristics, and there is still room for improvement and improvements are desired.

Purpose of the Invention In view of the above circumstances, the present inventors have conducted various studies and examinations to improve the conventional water-based ink, and as a result of the above-mentioned conventional water-based ink, the present inventors have added a specific compound to the ink composition. It has been found that the above problems can be overcome. Therefore, an object of the present invention is to provide an aqueous ink composition for inkjet recording that does not cause clogging of printing nozzles even after being left for a long period of time.

Another object of the present invention is to provide an aqueous ink composition for inkjet recording that has low viscosity, high surface tension, and high electrical conductivity.

Still another object of the present invention is to provide an aqueous ink composition for inkjet recording that has low toxicity and good chemical stability.

Structure of the Invention The above and other objects of the present invention can be achieved by adding a predetermined amount of an imidazolidinone derivative to an aqueous ink composition for inkjet recording.

That is, the present invention is an aqueous ink composition for inkjet recording, in which at least /14 of a /, J-substituted-,1-imidazolidinone compound represented by the following general formula is added /~Sθ weight fk5b Regarding the above-mentioned ink composition, characterized in that: 1 In the general formula, R1 and R2 independently represent an alkyl group, a hydroxyalkyl group, or an alkyl ether group each having a carbon atom number/-1.

The 3-substituted-two-imidazolidinone compound used in the present invention has extremely excellent dye-dissolving ability, high surface tension, extremely low viscosity, low insertion property, and excellent chemical stability. Therefore, it can be said that it has all of the above-mentioned required characteristics of an ink composition for inkjet valve distribution.
It can be said that it is particularly suitable for use in this type of ink composition.

Specific examples of /, 3-i#, substituted-λ-imidazolidinone compounds used in the present invention include /, 3-nomethyl-coimidazolidinone, /, 3-diethyl-2-substituted imidazolidinone, l, 3-diprobyl-twoimidazolidinone, /-methyl-3-ethyl-twoimidazolidinone, /-methyl-3-propyl-niimidazolidinone, /-methyl-3-butylucoimidazolidinone, /.

3-(two-hydroxyethyl)-Koimijizoli-)/
l-methyl-,7-(,2-hydroxyethyl)-twoimidazolidinone, /-methyl-,? −(
, 2-hydroxyethyl)-2-imidazolizonone,
l-Methyl-3-(3-hydroacizolobyl)-twoimidazolidinone, /-methyl-J-methoxyethyl)-twoimidazolidinone, /-methyl-3-
(λ-ethoxyethyl)-twoimidazolidinone,
Examples include i,3-,y-(two-ethoxyethyl)-two-imidazolidinone.

This /*3-replaced-2-imidazolidinone compound is present in the ink composition of the present invention based on the total weight of the composition. Used in amounts ranging from r07ij cane staff.

If this imidazolidinone compound is used in an amount less than 1% by weight, it will not be possible to impart the desired effect to the ink composition, and even if it is used in an amount exceeding 30% by weight, the effect will not be higher than the specified effect. Therefore, in the present invention, it is preferable to use the imidazolidinone compound within the above range.

The other components used in the aqueous ink composition of the present invention do not need to be any special components, and commonly used components can be used in commonly used proportions. Such other ingredients include colorants such as dyes, conductivity, iMl conditioners, bactericidal or antimicrobial agents, and water.

Effects of the Invention Thus, according to the present invention, the following various excellent effects can be achieved based on the use of specific imidazolidinone compounds in specific proportions. That is, the ink composition of the present invention has low viscosity, high surface tension,
It has high electrical conductivity, and as a result, there is no risk of clogging of the printing nozzle even after being left unused for a long period of time, and it has low toxicity and is chemically inert to materials in contact with the liquid.

Examples Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited in any way by these Examples.

In each example, all parts are by weight.

Example/Water g Shio,
Ribe/3-dimethyl-11 imidazolidinone
l 0 parts Potassium acetate 7 parts Sodium dihydroacetate / part Trisodium ethylenediaminetetraacetate θ,! Part r was mixed with the above gold component and dissolved, and then filtered through a 013 micron filter to obtain an aqueous ink composition for inkjet recording of the present invention. This ink has a viscosity of 8.2 cp at a liquid temperature of 2&'C and! ; It had a surface tension of 7 dyn/an. Further, even after this ink was filled into the printing nozzle and left for several months, it did not show any clogging phenomenon in the nozzle, and did not cause any problem in the jetting characteristics.

Example λ
! Water 7/, 7 parts/, 3
- Dimeterucoimidazolidinone / 3.3 parts Tetraethylene glycol S part N-methyl-2
-pyrrolidone black dye (Eisen SPT)
black) 5 parts sodium hydroxide
0.7 parts Omazine sodium O
, S part ethylenediaminetetraacetic acid is Nishi potassium
00.2 parts After thoroughly mixing and dissolving the above components, 0.00 parts.
It was filtered through a 3 micron filter for i5 to obtain an aqueous ink composition for inkjet recording of the present invention. The liquid temperature of this ink is 2.5'. Viscosity of 89 cp and Hiroza dyn/
It had a surface tension of Cm. In addition, this ink did not show any clogging of the nozzle even after several months of exsanguination after being filled into the printing nozzle, and did not cause any problem in jetting property.

Claims (1)

[Scope of Claims] In an aqueous ink composition for inkjet recording, at least seven kinds of 2-imidazolidinone compounds represented by the following general formula are added in an amount of 7 to 50% by weight. Characteristics of the above-mentioned ink composition: 1 In the general formula, R1 and R2 each independently represent an alkyl group, a hydroxyalkyl group, or an alkyl ether group having a carbon atom number of /~d.