JPH0730274B2 - Water-based recording ink - Google Patents

Description

The present invention relates to a water-based recording ink most suitable for inkjet recording, writing instruments, recorders, stamps, etc. It has excellent dryness,
In addition, the present invention relates to a water-based recording ink that has less bleed-through and shows through, and can expand the selection range of recording paper.

(Prior Art) Recording by the inkjet recording method has low noise,
In addition, since high-speed recording and colorization are easy and plain paper can be used, application and development to various printers, facsimiles, etc. have been actively made in recent years.

As an inkjet recording method, various characteristic recording methods have been proposed by various combinations of an ink droplet control method and an ejection method, and the ink using this is also oily and water-based. A water-soluble dye, a water-soluble organic solvent, and water as essential components are used.

(Problems to be Solved by the Invention) However, even in the above-mentioned ink jet recording system, the ink must be continuously and stably ejected as fine liquid droplets from the fine nozzle orifices, and therefore, the above-mentioned ink for aqueous recording. As for the ink, a problem to be solved is nozzle clogging.

As a solution to this, a water-soluble dye, a water-soluble organic solvent and a water-based recording ink composition containing water as essential components are used as a moisturizing agent for suppressing the drying of the inside of the nozzle and the nozzle tip, and a dye solvent for preventing the precipitation of the dye. In addition, a fungicide or the like for suppressing the generation of mold has been blended.

However, the ink particles flying from the nozzle orifice need to be dried rapidly after adhering to the recording paper, which is a condition contrary to the condition of not drying it at the nozzle tip. The use of a non-drying composition results in impaired quick-drying property on recording paper.

Further, in order to solve the quick-drying property on the recording paper, when a recording paper in which ink is rapidly permeated and dried is used, the selection range of the recording paper to be used is limited.

In addition, many recording papers in which ink is rapidly permeated and dried impair the image quality due to bleeding, show-through, etc., which further narrows the selection range.

Therefore, the present invention can record not only ink jet recording paper but also ordinary commercially available plain paper (writing paper, recorder paper, copy paper, etc.) with image quality which is not different from that recorded on ink jet recording paper. It is intended to impart characteristics such that the quick-drying property after recording is excellent and the nozzle is not clogged.

(Means for Solving Problems) In order to solve the above object, in the present invention, a water-soluble dye,
In a water-based recording ink containing a water-soluble organic solvent and water as essential components, a polyoxyethyl allyl ether compound represented by the following general formula (In the formula, M is a halogen or a halogen compound such as fluorine or chlorine, and n is in the range of 3 to 20.) and an aqueous recording ink is proposed.

The water-soluble dye that can be used in the present invention is, among direct dyes and acid dyes, a dye that has good solubility in water and a water-soluble organic solvent and that improves the water resistance and weather resistance of a recorded image. # 17, # 19, # 38, # 108, # 154 CIAcid Black # 2, # 7, # 31, # 94, # 155 CIDirect Blue # 2, # 6, # 25, # 98, # 194 CIAcid Blue # 7 , # 9, # 104, # 167, # 234 CIDirect Red # 1, # 9, # 17, # 28, # 99 CIAcid Red # 18, # 52, # 94, # 143, # 259 CIDirect Yellow # 8, # 27, # 58, # 86, # 142 CIAcid Yellow # 7, # 17, # 42, # 65, # 155, etc. can be mentioned. The amount of addition is determined in consideration of the dissolution and precipitation of the dye after addition. 9Wt% or less is desirable.

Examples of the water-soluble organic solvent include ethylene glycol, di- or tri- or polyethylene glycol, propylene glycol, dipropylene glycol, dipropylene glycol, hexylene glycol, glycerin, polyglycerin, and other polyhydric alcohols, ethylene glycol monomethyl. Ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl glycol, diethylene glycol monobutyl glycol, diethylene glycol, diethylene glycol dimethyl ether, triethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monomethyl ether Acetate, ethyl Alkyl ethers of polyhydric alcohols such as glycol monoethyl ether acetate, diethyl glycol monoethyl ether acetate, glycerin monoacetate and the like, or acetates thereof, or amino alcohols can be used alone or in combination of two or more, and addition thereof The amount is preferably in the range of 8 to 40 Wt% in consideration of the ejection stability and low temperature stability of the ink after addition.

The polyoxyethylene allyl ether of the above structural formula added to the water-based recording ink containing the above water-soluble dye, water-soluble organic solvent and water as essential components shows that the ink droplets are stable according to the research conducted by the inventors of the present application. There is almost no foaming property that is harmful to discharge,
It is a compound that has been found to have characteristics such as having particularly excellent penetrating power and promoting the solubility of the dye, but in the above structural formula, when n is 3 or less, it becomes difficult to dissolve in water, Poor penetrating effect and unstable low temperature stability of ink, and when n is 20 or more, it has excellent penetrating power, but bleeding and show-through appear on printed products. There is an evil.

In the above structural formula, M is fluorine, chlorine, bromine,
A halogen atom or a halogen compound such as iodine can be used.

Further, the addition amount of polyoxyethylene allyl ether of the above structural formula is preferably 0.1 to 10 Wt%, and if the viscosity of the ink in this range is adjusted to the range of 1.5 to 16 centipoise at 25 ° C., the ejection stability can be obtained.

However, if the addition amount is 0.1 Wt% or less, the penetrating power to paper is poor, and quick drying property after recording cannot be obtained.

Further, when the addition amount is 10 Wt% or more, the quick-drying performance is excellent, but the viscosity of the ink becomes high and the ejection stability of the ink is adversely affected.

The ink according to the present invention may contain a fungicide such as dioxane, sodium dehydroacetate or sodium benzoate for long-term storage to the extent that the characteristics are not impaired.

(Function) The water-based recording ink according to the present invention can record not only on an inkjet recording sheet but also on an ordinary commercially available plain paper with an image quality almost the same as that recorded on the inkjet recording sheet, In addition, it has excellent quick-drying properties after recording and does not cause nozzle clogging.

That is, in the inkjet recording paper, ink droplets collide and adhere to the paper surface from the nozzle orifice of the inkjet recording device, and the apparent drying at the time of permeation and absorption is increased,
In addition, in order to obtain clear image quality with less bleed-through, it has been specially devised so that the permeation absorbency does not change, but on plain paper its size, water absorption, porosity, air permeability, smoothness Permeation absorbency changes according to physical properties such as degree. In order not to impair the image quality in response to such a change in the properties of the paper, the ink itself has an appropriate penetrating force as a quick-drying ink, and further, the ink spreads uniformly and its size is large. Is required to be suppressed.

According to the research conducted by the inventors of the present application, the polyoxyethylene allyl ether having the above structural formula is an excellent penetrant, and by adding it to an aqueous recording ink, an appropriate penetrating force is imparted to the ink, Bleed-through is less likely to show through, the solubility of the dye is promoted, and problems such as nozzle clogging can be solved.

That is, when a small amount of the above polyoxyethylene allyl ether was added to an aqueous recording ink containing a water-soluble dye, a water-soluble organic solvent and water as essential components and dropped by about 2 μm on various paper surfaces, which paper surface However, the drying time was 30 seconds or less, which was a sufficient drying property, and the printing by the inkjet printer was good. Therefore, when the ink according to the present invention is used, the selection range of recording paper can be expanded.

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

Formulation 1 CIDirect Black # 19 2.5Wt% Glycerin 15.0Wt% Diethyl glycol 5.0Wt% Sodium dehydroacetate 0.1Wt% Polyoxyethylene chlorophenol ether (n =
8) 3.0Wt% ion-exchanged water 74.4Wt% Formulation example 2 CIAcid Blue # 234 2.0Wt% PEG # 300 15.0Wt% Diethylene glycol monoethyl ether 5.0Wt% Sodium dehydroacetate 0.1Wt% Polyoxyethylene chlorophenol ether (n =
8) 4.0Wt% Ion-exchanged water 73.9Wt% Formulation 3 CIDirect Yellow # 142 4.0Wt% Ethylene glycol 12.0Wt% PEG # 300 10.0Wt% Sodium dehydroacetate 0.1Wt% Polyoxyethylene chlorophenol ether (n = 10) 2.5 Wt% Ion-exchanged water 71.4Wt% Comparative formulation example 1 CIDirect Black # 19 2.5Wt% Glycerin 15.0Wt% Diethylene glycol 5.0Wt% Sodium dehydroacetate 0.1Wt% Ion-exchanged water 77.4Wt% Comparative formulation example 2 CIAcid Blue # 234 2.5Wt% PEG # 300 15.0Wt% Diethylene glycol monoethyl ether 5.0Wt% Sodium dehydroacetate 0.1Wt% Ion-exchanged water 77.9Wt% Mixing the composition of the above-mentioned formulation examples 1-3 and comparative formulation examples 1 and 2, a membrane filter with a pore diameter of 0.45μ After suction filtration with
The ink was prepared by degassing under reduced pressure.

The obtained ink was subjected to various recording tests using a drop-on-demand type inkjet recording device under the conditions of a frequency of 2 KHZ, a pulse voltage of 80 V and a nozzle diameter of 60 μ, and the following properties (1) to (3) were tested.

(1) Continuous Discharge Stability A continuous discharge test was carried out in a constant temperature environment chamber in an atmosphere of 5 ° C., 20 ° C. and 40 ° C. for 48 hours each, and stable and clear recording was obtained under all conditions.

(2) Discharge responsiveness We performed intermittent discharge every 15 minutes and discharge after leaving for 4 weeks. In both cases, there was no abnormality such as nozzle clogging.
Stable and clear recording was obtained, which was completely the same as the desired recording state.

(3) Recording Dryness Inkjet recording paper (silica-coated paper) Writing paper A
(Stationery paper conforming to JIS / P3201 standard), Writing paper B
(Office paper conforming to JIS / P3202 standard), Writing paper C
Drying properties were compared by the following tests using four types of recording paper (note paper conforming to JIS / P3203 standard).

(A) Transfer Test Method 5 lines per line on the above paper using an inkjet printer.
It was set to print at intervals of one second and printed for 1 minute (12 lines). Place this printed paper on the glass plate, and after 10 seconds, align the same quality paper with the print surface, put the glass plate and the weight together on it, put a weight of 500 g, press the two papers together, and let stand for 1 minute. When released, the printing time when the print was transferred to the overlapped paper was examined. The test results are shown in Table 1.

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

(B) Rubbing test method The printed surface was rubbed with a finger immediately after recording (1 to 2 seconds after recording and printing) on the above-mentioned paper with an inkjet printer, and then the printed state was observed. The results are shown in Table 2.

(Evaluation of image quality) Observing the bleeding state and show-through state of the image recorded on each of the above papers by an inkjet printer,
The image quality was evaluated. The results are shown in Tables 3 and 4.

(A) Bleeding state (B) Show-through state In Tables 3 and 4, ◯: almost no condition Δ: little condition

As is clear from the above Tables 1 to 4, the commercially available water-based inks have no bleeding or show-through on any of the papers, but have a quick-drying property only when the inkjet recording paper is used. While the range of recording papers that can be used is limited, the recording ink according to the present invention containing the polyoxyethylene allyl ether is not limited to inkjet recording papers, but also writing papers A and B,
It was confirmed that even with respect to C, it has an excellent quick-drying property, and there is almost no bleeding or show-through on any paper, and the image quality is not impaired.

(Effects of the Invention) As is clear from the above, the aqueous recording ink according to the present invention satisfies various characteristics for inkjet recording,
It is a good water-based recording ink that produces particularly clear recording and does not cause nozzle clogging, which is often found in many ink-jet recording inks, and has an excellent speed that does not impair the image quality that is characteristic of this water-based ink. Due to the dryness, the selection range of commercially available writing instrument paper is widened, and the speed of the inkjet recording apparatus can be increased.

The water-based recording ink according to the present invention can be used not only for ink jet recording but also as various water-soluble recording inks for writing instruments, recorders, stamps and the like.

Claims (1)

[Claims] 1. A water-based recording ink containing a water-soluble dye, a water-soluble organic solvent and water as essential components, which is a compound represented by the following general formula: (In the formula, M is a halogen or a halogen compound, and n is 3 to 20.
Is the range. ) A water-based recording ink comprising: