JP2953040B2 - Inkjet recording ink - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink used for ink jet recording that forms characters and images on a medium such as recording paper by flying ink droplets.

[Prior art] Conventionally, as an ink for inkjet recording, an aqueous ink composed of a dye and water is mainly used from the viewpoint of safety, and various water-soluble dyes are dissolved in water or a solvent composed of water and a water-soluble organic solvent. What melt | dissolved and what added various additives as needed is used.

Advantages of these ink jet recordings are direct recording, the process is simple, no noise because they are not of the impact type, easy to colorize, high-speed recording is possible, and plain paper is used. It has excellent features such as low running cost because it can be performed, and high-resolution recording for discharging minute ink droplets, and its future potential is attracting attention.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, as a common technical problem of the aqueous dye-soluble ink, the scratch resistance of printed matter on paper after recording and the water resistance to sweat and the like are considered. Poor, variations in print quality depending on paper type, slow drying speed, and the like.

Accordingly, the present invention is to solve such a problem, and an object of the present invention is to achieve a high degree of resistance to ink jet recording in which characters and images are formed on a medium such as recording paper by flying ink droplets. An object of the present invention is to provide a highly reliable ink jet recording ink which has abrasion resistance and water resistance, suppresses variations in print quality depending on paper types, has a fast drying property, and does not cause clogging.

[Means for Solving the Problems] An ink jet recording ink of the present invention is an ink jet recording ink for recording characters and images with a liquid ink, which comprises water, a coloring component, a high boiling point and a low volatile organic solvent. And carboxymethylcellulose and polyvinylpyrrolidone.

[Action] The ink for inkjet recording of the present invention has both carboxymethylcellulose and polyvinylpyrrolidone in the ink composition, thereby reducing the hygroscopicity of each and improving the quick-drying property. Also improve. In other words, the addition of a very small amount enables a high degree of scratch resistance and water resistance.

[Examples] Hereinafter, the present invention will be described specifically with reference to Examples.
The present invention is not limited to this.

As the colorant of the inkjet recording ink of the present invention, water-soluble dyes used in conventional inks can be used, and specifically, CI Direct Black 19, 22, 154 CI Direct Yellow 12, 16 , 86 CI Direct Red 9, 13, 17 CI Direct Blue 78, 90 CI Acid Black 2, 31, 52 CI Acid Yellow 23, 25 CI Acid Red 37, 52, 92, 94 CI Acid Blue 9, 22 CI Food Black 2 Further, as the pigment, an inorganic pigment (carbon black), an organic pigment (insoluble azo pigment, soluble azo pigment, phthalocyanine pigment, isoindolinone pigment, quinacridone pigment, perinone / perylene pigment) and the like can be used. In addition, a processed pigment (graft carbon or the like) having a pigment surface treated with a resin or the like can also be used.

The solvent that can be used in the ink jet recording ink of the present invention is preferably composed of ion-exchanged water and a high-boiling / low-volatility water-soluble organic solvent, and has 1 to 4 carbon atoms such as alkyl alcohol ethers, ketone or Keto alcohols, ethers, polyalkylene glycols,
Alkylene glycols in which the alkylene group contains 2 to 6 carbon atoms, glycerin, lower alkyl ethers of polyhydric alcohols, N-methyl-2-pyrrolidone, triethanolamine, 1-3-dimethyl-2-imidazolidinone and the like However, the present invention is not limited to this. These water-soluble organic solvents can be used alone or in combination of two or more.

As carboxymethyl cellulose used in the inkjet recording ink of the present invention, generally, frozen dessert stabilizer,
It is used as a food thickener, a synthetic detergent, a paint, a surface sizing agent, and the like. The viscosity of a 2% solids aqueous solution is desirably 100 mPa.s or less at room temperature (at 25 ° C). Are sunrose from Sanyo Kokusaku Pulp and cellogens 5A, 6A, 7A, PR, BSH-6, F-7A from Daiichi Kogyo Seiyaku.

The polyvinylpyrrolidone used in the inkjet recording ink of the present invention preferably has a molecular weight in the range of 10,000 to 400,000, and specifically, has a K value of 1 such as GAF or BASF.
5, 30, 60 and 90 are acceptable.

Although the basic constitution of the present invention is as described above, conventionally known dispersants, surfactants, viscosity adjusters, surface tension adjusters, specific resistance adjusters, pH adjusters, antifungal agents, chelating agents and the like are required. It can be added according to.

Regarding the physical properties of the ink, the ink viscosity when the operating temperature is set to 0 ° C to 50 ° C is required to be 30 mPa.s or less due to the stability of ink supply and the stability of ink droplet formation and flight under high-speed response of the head. And 1.5 mPa.s to 15.0 mPa.s is more preferable for realizing high-speed response.

Examples of the present invention and comparative examples will be specifically described.

(Example 1) CI Direct Black 19 3 wt% Ion-exchanged water 90 wt% Carboxymethylcellulose (Serogen 5A: Daiichi Kogyo Seiyaku) 0.5 wt% Polyvinylpyrrolidone K = 15 (GAF) 0.5 wt% Glycerin 3 wt% Ethanol 3 wt% A specific method for preparing the ink for inkjet recording of the present invention will be described below.

First, add carboxymethylcellulose and polyvinylpyrrolidone to a solution of ion-exchanged water and glycerin.
Dissolve at a ratio of 1: 1 and further add a dye, 90 ° C to 100
Stir and dissolve at ℃.

At this time, the highly volatile ethanol is added after cooling the ink after dissolution.

Finally, if necessary, the mixture is filtered through a filter or the like to remove dust and the like.

Hereinafter, Examples 2, 3, and 4 of the present invention, and Comparative Examples 1, 2, and 3
Was prepared in the same manner.

(Example 2) CI Direct Black 19 3 wt% Ion-exchanged water 90 wt% Carboxymethylcellulose (Selogen 5A: Daiichi Kogyo Seiyaku) 0.5 wt% Polyvinylpyrrolidone K = 30 (GAF) 0.5 wt% N-methyl 2-pyrrolidone 3 wt% % Ethanol 3wt% (Example 3) CI direct black 19 3wt% ion exchange water 90wt% carboxymethylcellulose (Selogen 5A: Daiichi Kogyo Seiyaku) 0.5wt% polyvinylpyrrolidone K = 60 (GAF) 0.5wt% diethylene glycol 3wt% Ethanol 3 wt% (Example 4) CI Direct Black 19 3 wt% Deionized water 90 wt% Carboxymethylcellulose (Serogen 6A: Daiichi Kogyo Seiyaku) 0.5 wt% Polyvinylpyrrolidone K = 30 (GAF) 0.5 wt% Triethanolamine 3 wt% % Ethanol 3wt% (Example 5) Carbon black (MA-100: Mitsubishi Kasei) 5wt% ion exchanged water 90.7 wt% Carboxymethylcellulose (Selogen PR: Daiichi Kogyo Seiyaku) 0.5 wt% Polyvinylpyrrolidone K = 30 (GAF) 0.5 wt% Glycerin 3 wt% Polymer dispersant 0.3 wt% Specific of the ink jet recording ink of Example 5 Various preparation methods are described below.

First, add carboxymethylcellulose and polyvinylpyrrolidone to a solution of ion-exchanged water and glycerin.
Dissolve at a ratio of 1: 1, add carbon black and a polymer dispersant, and mechanically disperse with an attritor or the like.

Finally, if necessary, the mixture is filtered through a filter or the like to remove dust and the like.

(Comparative Example 1) CI Direct Black 193 3 wt% Ion-exchanged water 90 wt% Carboxymethylcellulose (Selogen 5A: Daiichi Kogyo Pharmaceutical) 1 wt% Chryserin 3 wt% Ethanol 3 wt% (Comparative Example 2) CI Direct Black 193 3 wt% ion exchange Water 90 wt% Polyvinylpyrrolidone K = 30 (GAF) 1 wt% Glycerin 3 wt% Ethanol 3 wt% (Comparative Example 3) CI Direct Black 19 3 wt% Deionized water 91 wt% Glycerin 3 wt% Ethanol 3 wt% Next, practice of the present invention An example and a method of evaluating the ink of the comparative example will be described.

First, an ink nozzle clogging evaluation method will be described.

Clogging evaluation: A known on-demand type ink jet storage device is filled with the inks of Examples and Comparative Examples of the present invention, and can be printed immediately after being left for 1 month without a cap in a nozzle at 50 ° C. ○ Cleaning was performed by circulating the ink. Printing was possible by △. Printing was not possible.

Next, a method for evaluating variations in print quality depending on paper types will be described.

Printing quality (bleeding) depending on paper type: well-known ink-on-demand type inkjet device (Seiko Epson HG
-3000) with the inks of Examples and Comparative Examples of the present invention, RICOPY-6000 paper, GILBERT BOND paper, XEROX-4024.
Bit image printing and character printing were performed on paper and recycled paper (Yamayuri: Honshu Paper), and the printing quality (bleeding) was evaluated. No bleeding ◎ Little bleeding ○ Some bleeding △ Some bleeding ×.

Further, the drying speed of the printed matter was evaluated as follows.

Print drying speed: Solid printing is performed on PPC paper and rubbed with PPC paper to evaluate the time when the paper is not stained. Within 10 seconds ◎ Within 10 to 20 seconds ○ 20 to 30 seconds △ More than 30 seconds Classified by × did.

Further, the scratch resistance and water resistance of the printed matter were evaluated as follows.

Scratch resistance: Character printing was performed on PPC paper in the same manner as the evaluation of print quality, and the completely dried ink dot surface was printed on PPC paper.
It was rubbed once with a load of Kg / cm ² , and the stain around the dots and the adhesion of the ink to the PPC paper were evaluated. No stain was found. ほ と ん ど Little stain was found.

Water resistance: As with scratch resistance performs character printed on PPC paper, the complete dried ink dot surface with a commercially available wet tissue rubbed once with a load of 4 Kg / cm ^2, peripheral dots dirt and to wet tissue The adhesion of the ink was evaluated, and there was no stain. ほ と ん ど There was almost no stain.

The inks of the examples of the present invention and the comparative examples were evaluated by the above evaluation methods.

Table 1 shows composition ratios and evaluation results of Examples and Comparative Examples of the present invention.

Comparative Example 1 was an ink containing only carboxymethylcellulose, but the drying speed was slightly slow, and the scratch resistance and water resistance were insufficient.

Although the ink of Comparative Example 2 contained only polyvinylpyrrolidone, the clogging property was good.
The drying property is reduced, and the scratch resistance and water resistance are poor.

The ink of Comparative Example 3, which contains neither carboxymethylcellulose nor polyvinylpyrrolidone, is excellent in quick-drying property. However, if left without a cap, the nozzle is clogged immediately and printing is possible. In addition, scratch resistance and water resistance are not sufficient.

In contrast to these inks, the inks of Examples 1 to 5 have both carboxymethylcellulose and polyvinylpyrrolidone, thereby improving the abrasion resistance and water resistance compared to the case where each is used alone, and further causes clogging. The quick drying property and the print quality of paper are improved.

[Effects of the Invention] As described above, according to the ink jet recording ink of the present invention, water, a coloring component, a high boiling point and a low volatility are obtained in the ink jet recording ink for recording characters and images with a liquid ink. Contains water-soluble organic solvent, carboxymethylcellulose, and polyvinylpyrrolidone to improve the scratch resistance and water resistance, which have been a problem in the past, and to suppress the variation in printing quality depending on the paper type, and to prevent clogging quickly. It has the effect of improving dryness.

Also, recycled paper, which is expected to spread rapidly in the future,
It also has the effect of enabling clear recording without bleeding.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-124170 (JP, A) JP-A-50-72712 (JP, A) JP-A-63-280781 (JP, A) JP-A 55-127 48266 (JP, A) JP-A-4-132773 (JP, A) JP-A-4-46970 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C09D 11/00-11 / 20

Claims (1)

(57) [Claims] 1. An ink jet recording ink for recording characters and images using a liquid ink, comprising water, a coloring component, a high boiling and low volatile water-soluble organic solvent, carboxymethyl cellulose and polyvinylpyrrolidone. Ink for inkjet recording.