JPH01266173A - Water-base recording ink - Google Patents

Abstract

PURPOSE:To prevent clogging of a nozzle and improve the delivery stability, drying property after recording on plain paper and quality of printed characters, by mixing a water-soluble dye with a water-soluble org. solvent, water, and a particular compd. CONSTITUTION:9wt.% or less water-soluble dye (e.g., C.I. Direct Black #19) is mixed with 40wt.% water-soluble org. solvent (e.g., glycerin), water, 1.0-10wt.% polyoxyethylene benzyl ether of the formula (wherein n is 3-15), and optional additives such as surfactants and humectants.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an aqueous recording ink suitable for inkjet recording, a writing instrument, a recorder, a stamp, etc., and particularly a nozzle for inkjet recording. There is no clogging, the discharge is stable, and it dries quickly after recording.
The present invention also relates to an aqueous recording ink that exhibits excellent print quality with little bleeding or show-through.

(Prior art) Recording using the inksheet recording method has low noise.
In addition, it is easy to record at high speed and in color, and it is possible to use paper that passes through the paper, so it has been actively developed and applied to various printers, facsimile machines, etc. in recent years.

As inkjet recording methods, various distinctive recording methods have been proposed based on various combinations of ink droplet control methods and ejection methods, and the inks used for these methods are either oil-based or water-based.

As water-based recording inks, those containing water-soluble dyes, water-soluble organic solvents, and water as essential components are used.

(Problem to be Solved by the Invention) However, in the above-mentioned inkjet recording method, the ink must be continuously and stably ejected as uniform droplets from a fine nozzle orifice. Issues to be addressed include the issue of ejection stability and the issue of nozzle clogging.

Further, problems to be solved after recording with aqueous recording inks include problems such as drying properties, set-through, and bleeding.

However, these problems are all related, and no method has yet been found to solve them.

On the other hand, when using plain paper as the recording paper in the inkjet recording method, normal water-based recording inks have a high surface tension, and penetration is extremely slow due to the sizing agent on the surface of the paper, making it difficult to print. Because it does not dry, plain paper has not been used as recording paper, but paper with a specially coated surface has been used.

As a method for printing on plain paper, it has been proposed to increase the alkalinity of the ink and dissolve the sizing agent to apparently speed up the drying speed.In this case, there are no problems such as show-through or bleeding, but On the other hand, the pH of the ink is 13 or higher, which poses a safety problem for the human body, and it is also difficult to print in color.

Furthermore, it is possible to increase the apparent drying speed on plain paper by increasing the permeability of the ink using surfactants, etc., but in this case, the surface tension of the ink is low, so
Since the ink permeates into the paper to fill the internal voids, problems such as show-through and bleeding occur.

Therefore, this invention eliminates nozzle clogging, has excellent ejection stability, and dries quickly even on plain paper after recording. Furthermore, there are no problems such as show-through or 7fF, and good printing is achieved. The purpose is to propose an aqueous recording ink that provides high quality.

(Means for Solving the Problems) In order to solve the above objects, the present invention provides waterborne dyes,
In an aqueous recording ink containing a water-soluble organic solvent and water as essential components, an aqueous recording ink containing a polyoxyethylene benzyl ether compound represented by the following general formula (wherein n is an integer in the range of 3 to 15). This paper proposes a recording ink.

Among direct dyes and acid dyes, the water-soluble dye that can be used in this invention is preferably a dye that has good solubility in water and water-soluble organic solvents and improves the water resistance and weather resistance of recorded images, such as C, 1, Direct Black
117.119.1138,! 1108.1154C
, 1, Ac1d Black 112.17.
131. Cloud 94, Mouth 155C, 1, Direct B
lue 12.16, cloud 25, @98.11+94
C, 1, Ac1d Blue 17.19, So 10
4, “167, 梼234C, 1, Direct Red
II, Minoru 9, #17.128, Kaji 99C, 1, Ac
1d Red Cloud 18, Kure 52, @94, Cao 143
, Dew 259C, 1, Direct Yellow 11
8, #27, Minoru 58.1186, Cloud +42C, 1, Ac
1d Yellow Summer 7.11? , 142. cloud 65
, Cloud 155, etc., and the amount added is 9Wt!, taking into consideration the dissolution and precipitation of the dye after addition! It is preferable to do the following.

Examples of water-soluble organic solvents include polyhydric alcohols such as ethylene glycol, di- or tri- or polyethylene glycol, propylene glycol, dipropylene glycol, hexylene glycol, glycerin, and polyglycerin, ethylene glycol methyl ether, and ethylene glycol. glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate,
Alkyl ethers of polyhydric alcohols such as ethylene glycol monoethyl ether acetate, diethyl glycol monoethyl ether acetate, glycerin monoacetate and their acetates, or amino alcohols, N-methyl-2-pyrrolidone, 1,3-dimethyl One or more types of nitrogen compounds such as mitazoline may be used in combination, and the amount added is preferably 40 W LX or less, taking into consideration the ejection stability and low temperature stability of the ink after addition.

According to research by the inventors of the present invention, the polyoxyethylene benzyl ether of the above structural formula, which is added to the aqueous recording ink containing a water-soluble dye, a water-soluble organic solvent, and water as essential components, is suitable for inkjet recording. It does not have foaming properties that are harmful to stable ejection of liquid, is odorless, is highly safe, and has the effect of improving the solubility of dyes in ink.

In particular, when this polyoxyethylene benzyl ether is added to an ink composition, it does not significantly lower the surface tension of the liquid and has sufficient penetration power into paper despite the ink composition having a high surface tension. has.

The amount of polyoxyethylene benzyl ether having the above structural formula added to the ink is 1. θ~lOψtX is desirable;
If it is less than t, owtx, the permeability to the paper will be poor, and quick drying after recording will not be obtained.Also, even if more than twtx is added, there will be no change in the permeability to the paper, and the ink sheet will increase due to the high viscosity of the ink. This adversely affects ink ejection stability during recording.

In addition, if the number n of added moles of diethylene oxide in the polyoxyethylene benzyl ether of the above structural formula is less than 2, the dissolution stability of the ink may be impaired depending on the type of dye and the amount of dye added. Also, if n is 16 or more, it will dissolve in the ink.

When this happens, the viscosity of the ink increases and the ejection stability of the ink is impaired.

On the other hand, in general, water-based ink has expanded the selection range of recording paper,
It is known that oily substances are added for the purpose of improving absorption into paper and improving the solubility of various dyes. These oily substances include vegetable oils, unsaturated fatty acids, higher alcohols, fatty acid esters, and mineral oils, which can be emulsified with surfactants to create emulsion-like inks, or solubilized with surfactants and various solvents. Let me.

Water-based inks have been prepared, but inks containing these oily substances have the drawbacks of extremely poor stability and high viscosity.

A solvent that has an 10H group in its molecule and is sparingly or slightly soluble in water can eliminate these drawbacks of inks containing oil-based substances and retain the characteristics of containing oil-based substances.
For example, 2-ethyl 1.6 hexyl deol, diethylene glycol hexyl ether, acetylene glycol, ethylene oxide adduct of acetylene glycol (
5 or less), ethylene tallycol pencil ether, etc., and these are added to the aqueous ink in an amount of 0.1 to 10.
By adding 0 Wt2, an aqueous ink composition having the characteristics of the above-mentioned oil-based substance-containing ink and also having good stability can be obtained.

Of course, since it is a substance that is poorly soluble or slightly soluble in water, it may be necessary to use a water-soluble organic solvent in order to dissolve it in water. It also acts very effectively as a solubilizer.

In addition to the above-mentioned components, the ink according to the present invention may contain a surfactant, a humectant, a magnetic shielding agent, etc., to an extent that does not impair its properties.

(Effects of the Invention) In summary, since the aqueous recording ink according to the present invention contains polyoxyethylene benzyl ether having the above structural formula, even if the surface tension of the ink is high, it has sufficient penetration into #11m paper. It has power. For this reason, it is not affected by the sizing agent on the paper surface, and when ink adheres to the paper surface, the wettability of diffusion is suppressed and it penetrates into the white part of the paper, but it does not rapidly penetrate into the voids inside the paper. suppressed.

Therefore, the aqueous recording ink according to the present invention has quick drying properties on ik paper as well as on inkjet recording paper, and can provide good print quality without bleeding or show-through.

In addition, this invention improves the solubility of dyes in ink, eliminates the problem of nozzle clogging due to dye precipitation, and provides good ejection stability, which makes it possible to increase the speed of inkjet recording devices. We can also respond accordingly.

Note that the aqueous recording ink according to the present invention is not limited to inkjet recording, and can be used as various water-soluble recording inks for writing instruments, recorders, stamps, and the like.

(Examples) Hereinafter, examples of the present invention will be shown, but the present invention is of course not limited to these examples.

Formulation example 1 C, 1, Direct Black 119
2.0Wtl glycerin 10.0Wt$ diethyl glycol s, owtx dehydroacetic acid sorter 0.1Wt polyoxyethylene benzyl ether (n = 5) 5.0
WL$ ion exchange water balance combination example 2 C, 1, Ac1d Blue 1234
2. Mouth WtXPEG key 200 8.0Wt! Diethylene glycol monoethyl ether s, owtx dehydroacetic acid sorter 0.1 Wtl polyoxyethylene benzyl ether (n = 8) 5.0
Wtl ion-exchanged water balance example 3 C, 1, Direct Yellow Key 142
2. OWL:PEG
l:100 10.0Wt
X polyoxyethylene alkyl ether t, owtx dehydroacetic acid sorter 0.1Wt! Polyoxyethylene benzyl ether (n = 3) 4.0
Wtl ion-exchanged water balance blending example 4 C, 1, 8 sid Black Cloud 94
2.0WtX diethylene glycol monobutyl ether acetate z, owtx propylene glycol a, owtzN-
Methyl-2-pyrrolidone5. [lWt$ Sodium dehydroacetate o, twtx Polyoxyethylene benzyl ether (n = 14) 3.0
wt% ion-exchanged water balance formulation example 5 C, 1, Direct Red 1128
2.0Wt$benzyl alcohol 1, OW LX
Chryse+) N10.0WtX Sodium dehydroacetate 0. lWt$ polyoxyethylene benzyl ether (n = 15) 6.0
Wt! Ion-exchanged water Balance example 6 C, 1, Ac1d Yellow
2.0Wtl ethylene glycol monobenzyl ether 2.0Wt$PE
G '200 1(1, (I
WLX dehydroacetic acid soda 0.1w
t% polyoxyethylene benzyl ether (n = 7) 5.0
WLX ion-exchanged water balance example 7 C, 1, Direct Black 119
2. OWt$ Acetylene Glycol
o, zwtxri! J (?IJ:/
10.0WH dehydroacetic acid sorter
0.1WL$ Polyoxyethylene benzyl ether (n = 8) 8.0
IIIL! Ion-exchanged water Balance example 8 C, 1, Ac1d Blue 2:14
2.0Wt12-ethyl-1,6-hexanedeol 1.0Wt! P.E.
G8200
10. OWt! Sodium dehydroacetate 0, IWLχ polyoxyethylene benzyl ether (n = 12) 6.0
WtX ion exchange test water balance example 9 C, 1, Direct Yellow 1142
2. OWL$ chrycerin to, owH diethylene glycol hexyl ether 0.5Wtl dehydroacetic acid sorter o, +wtx polyoxyethylene pencil ether (n = 5) -1,
To 0WtX: / shi)Lt-r--te)Lt (n =
I:l) 4.0 Wi, $ ion exchange water
Remainder blending example 10 C, 1, 8 cid Black 1194
2.0Wt! Diethylene glycol +o, owtz acetyl glycol EO adduct s, owtz dehydroacetic acid sorter 0.1 Wt$ polyoxyethylene pencil ether (n = 10) 5.0
Wt! Ion exchange water Remaining comparative formulation example 1 C, 1, Direct Black 119
2.0WtlPGE BOO12,0WtX Thiethylenetalicol 6. owtx dehydroacetic acid sortalo, lWt! Ion exchange water Remaining comparative formulation example 2 C, 1, Direct Blue 11234
2. OWL$Crycerin
12.0Wt$ diethylene glycol monoethyl ether s, owtx dehydroacetic acid sorter 0.1Wt$ ion-exchanged water Remaining comparative formulation example 3 C, 1, Ac1d Blue 12:14
2. OWt! glycerin
10.0Wt! Polyoxyethylene pencil ether (n = 2) 8.0Wt
l Dehydroacetic acid sorter 0.1Wt$
Ion exchange water Remaining comparative formulation example 4 C, 1, Direct Yellow 11142
2. OWt:PEG 1200
10. OWt! Sodium dehydroacetate
o, 1wtz polyoxyethylene hensyl ether (n = 18) 10.
0WtX ion exchange test water balance comparison formulation example 5 C, 1, Direct 1led B8
2. Owt%PEG 1300
15.0Wtl Sodium Dehydroacetate
0.1WtX dioctyl sulfosuccinic acid sorter z, owtx ion exchange water
The remaining compositions of Formulation Examples 1 to 1O and Comparative Formulation Examples 1 to 3 were mixed, filtered with suction through a membrane filter with a pore size of 0.45 JL, and then degassed under reduced pressure to prepare an ink.

The obtained ink was applied using a drop-on-demand type ink sheet recording device at a frequency of 2KIIZ and a pulse voltage of 80.
Various recording tests were conducted under the conditions of V and nozzle diameter of 60 wells, and the following properties (1) to (3) were tested.

(1) Continuous discharge stability A continuous discharge test was conducted in a constant temperature environment chamber at 5°C120°C and 140°C for 48 hours each.Formulation Example 1
~10 and Comparative Example 1.2, stable and clear records were obtained under all conditions. Comparative Formulation Example 2 did not clog at 5°C, and Comparative Formulation Example 4 did not clog at 5°C and 40°C. occured. Furthermore, Comparative Formulation Example 5 caused clogging, which was thought to be caused by air bubbles, under all conditions.

(2) Discharge responsiveness Intermittent dispensing every 15 minutes and dispensing after 4 weeks of standing were conducted, and in all cases, there were no abnormalities such as nozzle clogging in Formulation Examples 1 to 10 and Comparative Formulation Examples 1.2. , Were stable and clear recordings that were completely unchanged from the expected recording conditions obtained? Comparative formulation examples 2 to 5 were used for 4 weeks? Disturbances in printing were observed even after 1 hr of ejection.

(3) Recording drying inkjet recording paper (silica coated paper) writing paper A
(Stationery paper conforming to the JIS-P3201 standard),
The drying properties were compared using the following test using four types of recording paper: writing paper B (office paper that complies with JIS-P:1202 standards) and writing paper C (notebook paper that complies with JIS-P3203 standards). did.

(a) Transfer test method 1 line 5 on the above paper by inkjet printer
The printer was set to print at second intervals and was printed for 1 minute (12 lines). This printed paper was placed on a glass plate, and after 10 seconds, a paper of the same quality was placed on the printed surface, and a weight of 500 g was placed on top of the paper, and the two papers were pressed together.
After standing still for a minute and then separating the two papers, the printing time taken for the print to be transferred to the overlapping paper was examined. The test results are shown in Table 1.

Table 1 In Table 1, transfer within a printing time of 10 seconds means that the printing is not transferred at all in practical terms, and transfer with a printing time of 1 minute or more means that the printing is completely transferred.

(b) Friction Test Method Immediately after recording with an inkjet printer on the above paper (1 to 2 seconds after printing), the printed surface was rubbed with a finger, and then the ltQ of the printed state was determined. The results are shown in Table 2.

Table 2 Evaluation method O1 No change at all △: The print was rubbed off a little ×: It was rubbed and the print could not be recognized at all (evaluation of image quality) Smearing and show-through of images recorded on the above paper using an inkjet printer Observe the condition of
Image quality was evaluated. The results are shown in Tables 3 and 4.

(a) Bleeding condition Table 3 (b)′;A photo fm Table 4 In Table 3.4 O: Almost no condition △: Slight condition are shown respectively.

As is clear from the above test results, although there are no problems in continuous ejection stability and ejection response with general water-based inks (Comparative Examples 1 and 2), the recording drying properties of ink sheets using ink sheet recording paper are poor. It is not possible to record anything else.

The ink with lower surface tension and stronger penetrating power (Comparative Example 5) caused problems in continuous ejection stability and ejection response, and although it dries quickly on plain paper, it bleeds significantly, whereas the ink according to the present invention It has good continuous ejection stability and ejection response, and has excellent quick drying properties on inkjet recording paper and plain writing paper A, B, and C, and does not bleed on any paper. It was confirmed that there was almost no show-through and the image quality was not impaired.

Patent applicant: Taihohe Gyo Co., Ltd. Procedural negative n formal letter (voluntary) July 5, 1988

Claims (1)

[Claims] In aqueous recording ink containing a water-soluble dye, a water-soluble organic solvent, and water as essential components, a compound represented by the following general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (In the formula, n is (an integer in the range of 3 to 15).