JPH086057B2 - Oil-based ink for inkjet recording - Google Patents

Description

TECHNICAL FIELD The present invention relates to, for example, an oil-based ink for inkjet recording.

(Prior Art) An inkjet recording method is a method in which ink droplets are ejected from a recording head to adhere and permeate and absorb ink particles on a recording paper, and recording is performed with low noise and high speed recording. Since it is easy to make color and color, and there is a possibility that plain paper can be used, application and development to various printers, facsimiles, etc. have been actively made in recent years.

As these ink jet recording inks, an oil-based ink in which an oil-based dye is dissolved in an oil-based solvent, or an aqueous ink in which an aqueous dye is dissolved in an aqueous solvent is known.

(Problems to be solved by the invention) Among them, the oil-based ink generally has a wide selection range of recording paper, quick drying (permeation and absorption into paper), good recording paper water resistance, and nozzle clogging. It is known to have the advantage of reducing the amount of ink, but in the ink jet recording method as described above, the solvent evaporates at the nozzle, the dye solidifies or aggregates at the nozzle, and ink droplets are ejected. It has the problem of disappearing.

Further, in order to solve this problem, as the organic solvent of the oil-based ink, a high-boiling point solvent is generally used, but this high-boiling point solvent is inferior in the dissolving ability of the oil-soluble dye, so that it is affected by the dye-dissolving concentration. Since the print density at the time of recording cannot be obtained, there is a problem that the image quality is inferior.

Therefore, it is an object of the present invention to provide an oil-based recording ink that does not cause nozzle clogging and has high ejection stability, which is particularly suitable for an inkjet recording system.

(Means for Solving Problems) In order to solve the above problems, according to the present invention, one kind of paraffinic petroleum solvent, aromatic petroleum solvent, naphthene petroleum solvent, olefin petroleum solvent, esters and the like, or An oil-based ink for ink-jet recording, comprising an oil-soluble dye dispersed or dissolved in an organic solvent comprising a combination of two or more thereof, wherein the polyoxyethylene alkylamine is represented by the following general formula. (In the formula, R is an alkyl group having 6 to 18 carbon atoms, and n and m are 0.
It ranges from ~ 10. ) Is contained in an amount of 0.5 to 10 Wt%, and an oil-based ink for inkjet recording is proposed.

The oil-soluble dye that can be used in the present invention is not particularly limited, but those having good weather resistance of the recorded image are desirable in terms of use characteristics, for example, CISolvent Black 3,7,22,34,50 CISolvent Blue 14,25,35,48,108. CISolvent Yellow 3,14,16,33,56 CISolvent Red 18,24,27,122,135 etc. can be mentioned, and the addition amount is 20 Wt% or less in consideration of the dissolution stability after addition and the physical properties of the ink. It is desirable to do.

Further, as the organic solvent, it is desirable to use a high boiling point solvent having a slow evaporation rate in order to suppress the drying of the ink. For example, as the petroleum solvent, a paraffin petroleum solvent, an aromatic petroleum solvent, a naphthene petroleum solvent, an olefin are used. A mineral oil such as a petroleum solvent can be used. Further, esters such as ethyl benzoate, butyl benzoate, 2-ethylhexyl acetate, dibutyl phthalate, propyl adipate and dioctyl sebacate, and dibutyl cellosolve, phenyl cellosolve, hexyl cellosolve, butyl carbitol, dibutyl carbitol, dipropylene. One kind or two or more kinds of ethers such as glycol monomethyl ether can be used in combination.

Further, according to the study of the inventors of the present invention, the polyoxyethylene alkylamine represented by the above structural formula is a weak cationic nonionic activator, has excellent permeability and wettability, and contains a large amount of an oil-soluble dye in the organic solvent. In addition, it has excellent properties as a dissolution aid for a dye that can be stably dissolved.

In the structural formula of the polyoxyethylene alkylamine, R is an alkyl group having 6 to 18 carbon atoms,
Outside this range, regardless of the number of ethylene oxide added,
This is because the effect as a dissolution aid is poor. The reason why n and m are set to 0 to 10 is that the solubility of the dye becomes unstable and the solubility of the dye becomes unstable at 10 or more.

The amount of polyoxyethylene alkylamine added is 0.5 Wt with respect to the ink composition of the oil-soluble dye and its organic solvent.
%, Especially in consideration of ink physical properties and the like, the range of 0.5 to 5 Wt% is preferable.

(Effect of the Invention) The ink according to the present invention is one in which the polyoxyethylene alkylamine represented by the above structural formula is added to an oil-soluble dye and its organic solvent. There is a property as an excellent dissolution aid to the soluble dye, and by adding this, the oil-soluble dye in the ink component has a high printing density during recording,
Moreover, it is stably dissolved in the organic solvent.

Therefore, according to the present invention, a sufficient dye concentration can be obtained as an oil-based ink for inkjet recording, so that the image quality of a printed product is excellent.

Further, in the oil-based ink of the present invention, the addition of polyoxyethylene alkylamine slows down the evaporation of the organic solvent. As a result, drying of ink, aggregation of dye, etc. are less likely to occur, and further, nozzle clogging and the like are eliminated, and ejection stability is improved.

Further, generally, solvents having poor solubility are often low in odor and low in toxicity, but in this invention, addition of polyoxyethylene alkylamine, which has excellent dissolution aid properties, results in low solubility but low odor and low toxicity. The organic solvent can be used.

Further, since the ink according to the present invention is excellent in quick-drying property and water resistance, the recording paper has a wide selection range and can be used for plain paper which is generally commercially available.

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

Formulation 1 CISolvent Black 3 10Wt% Polyoxyethylene oleylamine (HLB = 5) 5 〃
Butyl benzoate 15 〃 EXXSOL D-100 (manufactured by Exxon Chemical Co., Ltd.) 70 〃 Blending Example 2 CISolvent Black 3 10Wt% Polyoxyethylene oil amine (HLB = 5) 5 〃 Hisosol SAS (manufactured by Nippon Oil Co., Ltd.) 15 〃 Ink Solvent 240 (Manufactured by Mitsubishi Oil Co., Ltd.) 70 〃 Formulation 3 CISolvent Black 3 10Wt% Polyoxyethylene stearylamine (HLB = 7.5) 4
〃 Butyl benzoate 15 〃 EXXSOL D-100 71 〃 Formulation 4 CISolvent Black 3 10Wt% Polyoxyethylene stearylamine (HLB = 7.5) 5
〃 Hysol Zol SAS 15 〃 Ink Solvent 240 72 〃 Comparative Formulation Example 1 CISolvent Black 3 5Wt% Butyl Benzoate 25 〃 EXXSOL D-100 70 〃 Comparative Formulation Example 2 CISolvent Black 3 5Wt% Hysosol SAS 25 〃 Ink Solvent 240 70 〃 Above In the composition, the composition excluding 50 Wt% of the solvent was mixed in a ball mill for 24 hours or more, 50 Wt% of the solvent was added thereto, and the mixture was further mixed in the ball mill for 24 hours or more, and then suction-filtered with a Teflon filter having a pore size of 1 μm or less. Adjust the ink,
A dissolution stability test was performed.

(1) Dye solubility test CISolvent Black 3 was selected as an oil-soluble dye, and various organic solvents and paraffin petroleum solvents (EXXSOL D-
100), aromatic petroleum solvent (Hisosol SAS), naphthenic petroleum solvent (Insolvent 240), and butyl benzoate with 1Wt%, 5Wt%, 10Wt% and 15Wt% of dye, respectively. At this time, without adding polyoxyethylene oleylamine (HLB = 5) which is a dissolution aid, 2.5 Wt%, 5 Wt%, 10 Wt
%, It was investigated whether or not there was a difference in the solubility of the dyes.

For the evaluation, after the mixture blended as described above was left at room temperature for one day, it was examined whether or not there was a residue when it was suction-filtered with a Teflon filter having a pore size of 1 μm. The results are shown in Table 1.

(2) Storage stability test The inks obtained in the above examples were sealed in glass test tubes and allowed to stand under the conditions of -5 ° C and + 60 ° C for 1 month.
The mixture was suction-filtered with a Teflon filter having a pore size of 1 μm and examined for the presence of residues. The results are shown in Table 2.

Claims (1)

[Claims] 1. A paraffin-based petroleum solvent, an aromatic petroleum solvent, a naphthene-based petroleum solvent, an olefin-based petroleum solvent, an organic solvent in which one or more kinds thereof are combined,
An oil-based ink for ink-jet recording comprising an oil-soluble dye dispersed or dissolved therein, which is a polyoxyethylene alkylamine represented by the following general formula. (In the formula, R is an alkyl group having 6 to 18 carbon atoms, and n and m are 0.
It ranges from ~ 10. ) 0.5 to 10 Wt% is contained in the oil-based ink for inkjet recording.