JPH1129728A - Recording liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a water recording liquid of a pigment dispersion type which gives recording exhibiting good waterproof, high saturation, high reliability, good printing quality of recorded articles and good fastness other than waterproof such as resistance to light and which shows good stability after long storage, even when the recording is conducted on a plain-paper for ink jet recording or writing implements. SOLUTION: In a recording liquid containing a mixture of not less than 2 pigments in an aqueous solvent, a pigment solid solution having an X-ray diffraction peak at a position different from that of a mixture obtained by merely physically mixing thereof is used as the mixture of pigments. The pigment solid solution is preferably a solid solution of a dichlorquinacridone and a non-substituted quinacridone. The recording solution is usable as a recording solution for ink jet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pigment-dispersed aqueous recording liquid, particularly a recording liquid suitable for an ink jet recording liquid or a writing implement.

[0002]

2. Description of the Related Art Conventionally, as a recording liquid for ink jet recording, an aqueous ink in which an acidic dye or a direct dye is dissolved in an aqueous medium, or a solvent-based ink in which an oil-soluble dye is dissolved in an organic solvent has been used. . Since the solvent-based ink is mainly composed of an organic solvent, it has a problem in terms of environmental safety, and its use is limited and cannot be used in offices and the like. On the other hand, since the water-based ink uses a water-soluble pigment, there is a problem that the recorded matter has poor water resistance, particularly when recorded on plain paper. Further, the recorded matter of the ink using these dyes is insufficient in light resistance. The same applies to the recording liquid for writing instruments. In order to improve the above problem, a pigment having excellent water resistance and light resistance is used as a coloring material, and an aqueous medium ink in which the pigment is dispersed in an aqueous medium is partially used. However, the conventional pigment-based aqueous dispersion ink has a problem that the saturation of the recorded matter is insufficient.

[0003]

DISCLOSURE OF THE INVENTION The present invention is intended for use in ink-jet recording or writing instruments, and has good water resistance, high chroma recording, high recording reliability, and high quality even when recorded on plain paper. The purpose of the present invention is to provide a pigment-dispersed aqueous recording liquid that is capable of recording with good fastness other than water resistance, such as excellent print quality and light resistance, and has good stability when stored for a long time. It is assumed that.

[0004]

Means for Solving the Problems The present inventors have conducted various studies on the improvement of the saturation, the water resistance, and the storage stability of a pigment-dispersed aqueous ink for a recording liquid. As a result, a recording liquid containing a specific pigment solid solution was used. It was found that the saturation of the obtained printed matter was improved, and the present invention was achieved. That is, the gist of the present invention is that, in a recording liquid containing a mixture of two or more kinds of pigments in an aqueous medium, the mixture of the pigments is subjected to X-ray diffraction at a position different from a position where a pigment of the same component is simply physically mixed. The recording liquid is a pigment solid solution having a peak of By performing printing using the recording liquid of the present invention, it is possible to obtain a high chroma recorded matter, and in addition to the print quality of the recorded matter, water resistance, it is possible to record good fastness other than water resistance such as light resistance. In addition, the stability of the recording liquid is good, and the pigment does not settle during storage for a long time.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In the present invention, a solid solution of a pigment refers to a solid solution in which two or more kinds of pigments are solid and dissolved with each other. The method for obtaining the recording liquid of the present invention may be any method as long as the recording liquid has the above characteristics. For example, two or more kinds of pigments are used, and a solid solution pigment obtained by solidifying them is appropriately dispersed. It can be obtained by processing (appropriate dispersant, disperser, media, dispersion time).

The method of preparing a solid solution is, for example, a method of mixing coarse crystals of two or more kinds of pigments and performing acid paste treatment to obtain fine crystals, which are then treated in a high dielectric constant organic solvent such as DMF. A method of mixing two or more types of crude crystals of pigment and ball milling with salt to make finer or treating the same with an organic solvent in the same manner, and separately treating two or more types of pigments with acid paste or soft milling After that, there is a method of mixing and treating with the same organic solvent, a method of mixing two or more kinds of pigment intermediates, and simultaneously synthesizing the pigment, and then treating with the method described above. Unlike X-ray diffraction of a pigment simply blended physically with the same component (blend product), any method can be used as long as a pigment solid solution having an X-ray diffraction peak not found in the blend product can be obtained. It may be.

As the pigment solid solution used in the recording liquid of the present invention, commercially available general ones can be used. Specifically, Pig. Red 207 (Scarlett,
Solid solution of 4,11-dichloroquinacridone and unsubstituted quinacridone), Pig. Red 206 (maroon, solid solution of quinacridone quinone and unsubstituted quinacridone), C
inquasia Red B RT-195-D (Solid solution of substituted dichloroquinacridone and unsubstituted quinacridone, manufactured by CIBA-GEIGY) Cinquasia
Red RT-280-D (solid solution of dichloroquinacridone and diketopyrrolopyrrole (DPP), CIBA
-GEIGY). These pigment solid solutions are chemically treated (ozone oxidation treatment, fluorination treatment, etc.) or dispersants, surfactants, etc. are physically or chemically bonded (grafted products, dispersants are dispersed). Etc. previously adsorbed beforehand) may be used.

Although the recording liquid of the present invention does not need to use a dispersant, it is preferable to add a dispersant. Examples of the dispersant used include various anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and polymer dispersants. Examples of anionic surfactants include fatty acid salts, alkyl sulfate salts, alkyl benzene sulfonates, alkyl naphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, alkyl phosphates, and polyoxyethylene alkyl sulfates. Salts, polyoxyethylene alkylaryl sulfate salts, alkane sulfonates, naphthalene sulfonic acid formalin condensates, polyoxyethylene alkyl phosphates, α-olefin sulfonates and the like. Non-ionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkyl aryl ethers, polyoxyethylene derivatives,
Oxyethylene, oxypropylene block copolymers, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene fatty acid esters, polyoxyethylene alkylamines, etc. No. Examples of the cationic surfactant and the amphoteric surfactant include alkylamine salts, quaternary ammonium salts, alkylbetaines, and aminooxides. Examples of the polymer dispersant include polyacrylic acid, styrene / acrylic acid copolymer, styrene / acrylic acid / acrylic acid ester copolymer, styrene / maleic acid copolymer, and styrene / maleic acid / acrylic acid ester copolymer. Polymer, styrene / methacrylic acid copolymer, styrene / methacrylic acid / acrylic acid ester copolymer, styrene / maleic acid half ester copolymer, styrene / styrene sulfonic acid copolymer, vinylnaphthalene / maleic acid copolymer And a vinyl naphthalene / acrylic acid copolymer or a salt thereof.

The aqueous medium used in the recording liquid of the present invention is mainly composed of water, but it is preferable to use a water-soluble organic solvent added to water. Examples of the water-soluble organic solvent include ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol (# 200, # 400), glycerin, alkyl ethers of the above glycols, N-methylpyrrolidone, 1,3- Examples include dimethylimidazolidinone, thiodiglycol, 2-pyrrolidone, sulfolane, dimethylsulfoxide, diethanolamine, triethanolamine, ethanol, isopropanol and the like.

[0010] In addition to the above components, a water-soluble resin, a fungicide, a bactericide, a pH adjuster, urea, and the like may be added to the recording liquid of the present invention as needed. The method for preparing the recording liquid of the present invention is carried out by mixing the above-mentioned components, grinding the pigment solid solution into fine particles using a disperser, and subjecting the mixture to a dispersion treatment.
As the dispersing machine, a ball mill, a roll mill, a sand grind mill or the like is used, and a sand grind mill is preferable. Further, it is preferable to use a collision-type jet mill (such as a nanomizer or an optimizer) or an ultrasonic disperser that does not use a medium because contamination is reduced. After grinding and dispersion, coarse particles are removed using a filter or a centrifuge. Components other than the pigment solid solution, dispersant, and water may be added after milling and dispersion treatment. Also, grinding,
Since the dispersion treatment can be carried out efficiently by preparing at a high concentration, it is preferable to finally dilute the treatment liquid prepared at a high concentration with an aqueous medium to adjust the concentration of the recording liquid.

The pigment solid solution is 1 to 10% by weight based on the recording liquid.
, But is preferably 2 to 7% by weight. The dispersant is used in an amount of 3 to 100% by weight based on the solid solution of the pigment, and preferably 5 to 50% by weight. The amount of the water-soluble organic solvent used in the recording liquid ranges from 5 to 30% by weight.
20% by weight is preferred. One kind of these dispersants and organic solvents may be used alone, but in some cases, more effects can be obtained by using two or more kinds in combination. Further, the effect of the pigment solid solution can be further improved by using two or more pigment solid solutions in some cases.

[0012]

By using the ink jet recording liquid of the present invention, it is possible to perform recording with good dischargeability and high reliability, good water resistance even when recording on plain paper, and high chroma of the recorded matter. It is possible to obtain a recorded matter which is high and has good fastness other than water resistance such as print quality and light fastness. Since the present invention has the above properties, it can be used as a recording liquid for other purposes, not limited to ink jet and writing instruments.

[0013]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto. In these examples, “parts” and “%” are expressed on a weight basis. Example 1 (Preparation of recording liquid) Composition of recording liquid Used amount (parts) Glycerin 16 Ethylene glycol 18 Lipolan PB-800 (manufactured by Lion Corporation) 1 Cinquasia Red B RT-195-D (manufactured by CIBA-GEIGY) 9 Deionized water 56 ─────────────────────────────── Total 100

Incidentally, Cinquasia Red BR
FIG. 1 shows an X-ray diffraction chart of a blended product obtained by physically mixing T-195-D (a solid solution of dichloroquinacridone (substituted type) and unsubstituted quinacridone) with the same components.
As shown in FIG. The above components were placed in a stainless steel container, and pulverized for 40 hours using a sand grinder together with 152 parts of glass beads having an average diameter of 0.5 mm.
After diluting and stirring the obtained liquid with 127 parts of ion-exchanged water, Pressure filtration was performed using a 5C filter paper, and the liquid obtained here was used as a recording liquid.

(Printing test) The recording liquid obtained by the method described in the above example was subjected to ink jet recording on electrophotographic paper (Xerox 4024 paper, Xerox product) by an ink jet printer (DeskWriter C manufactured by Hewlett-Packard). As a result, a stable and good discharge property was exhibited without clogging or the like, and a printed matter having good print quality was obtained.

(Evaluation of Print Density) The density of the printed matter obtained in the above print test was measured using a Macbeth reflection densitometer (RD914). The evaluation results are shown in Table 1 below. (Evaluation of Printed Color Tone) The color tone of the printed matter obtained in the above printing test was measured with a spectral color difference meter (trade name, SZ- # 80, manufactured by Nippon Denshoku Industries Co., Ltd.). The evaluation results are shown in Table 1 below.

(Water Resistance Test) The printed matter obtained in the printing test was immersed in tap water taken in a beaker for 5 seconds. After drying the printed matter,
The presence or absence of character stain was visually evaluated. The results were classified as follows and are shown in Table 1 below. ○ ────No letter stains △ ────Slight letter stains but no problem in practical use × 汚 れ Character stains are severe

(Light fastness test) The printed matter was irradiated with a xenon fade meter (manufactured by Suga Test Instruments Co., Ltd.) for 100 hours to visually evaluate the discoloration and discoloration. The results were classified as follows and are shown in Table 1 below. ○ ────Good △ ────Discoloration, but no practical problem × 実 用 Discoloration is severe

(Storage stability test of recording solution) The recording solution was sealed in a Teflon container and stored at 60 ° C for one month. The presence or absence of gelation or precipitate was visually evaluated. The results were classified as follows and are shown in Table 1 below. ○ ────No gelation or precipitate almost △ ────Slight gelation or precipitate observed but no practical problem × ────Gellation or precipitate is severe

Example 2 (Preparation of recording liquid) Composition of recording liquid Amount used (parts) Glycerin 16 Ethylene glycol 18 Lipolane PB-800 (manufactured by Lion Corporation) 1 Cinquasia Red B RT-280-D (CIBA-GEIGY) 9) Ion-exchanged water 56 １００ Total 100

Each of the above components was placed in a stainless steel container and pulverized for 40 hours using a sand grinder together with 152 parts of glass beads having an average diameter of 0.5 mm.
After diluting and stirring the obtained liquid with 127 parts of ion-exchanged water, Pressure filtration was performed using a 5C filter paper, and the liquid obtained here was used as a recording liquid. A printing test, a water resistance test, a light resistance test, a storage stability test, and evaluation thereof were performed in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

Example 3 (Preparation of recording liquid) Composition of recording liquid Used amount (parts) Glycerin 16 Ethylene glycol 18 Polystar S2-1020 (non-volatile content) (Styrene-maleic anhydride dispersant, NOF Corporation) 3 Pig. Red 2079 Deionized water 54 １００ Total 100

Each of the above components was placed in a stainless steel container, and pulverized for 40 hours using a sand grinder together with 152 parts of glass beads having an average diameter of 0.5 mm.
After diluting and stirring the obtained liquid with 127 parts of ion-exchanged water, Pressure filtration was performed using a 5C filter paper, and the liquid obtained here was used as a recording liquid. A printing test, a water resistance test, a light resistance test, a storage stability test, and evaluation thereof were performed in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

Example 4 (Preparation of Recording Solution) Composition of Recording Solution Used Amount (Parts) 2-Pyrrolidone 9 Glycerin 16 Ethylene Glycol 9 Polystar S2-1020 (Non-Volatile) (Styrene-Maleic Anhydride Dispersant, Japan Fat & Oil Co., Ltd.) 3 Pig. Red 206 9 Deionized water 54 ─────────────────────────────── Total 100

Each of the above components was placed in a stainless steel container and pulverized for 40 hours using a sand grinder together with 152 parts of glass beads having an average diameter of 0.5 mm.
After diluting and stirring the obtained liquid with 127 parts of ion-exchanged water, Pressure filtration was performed using a 5C filter paper, and the liquid obtained here was used as a recording liquid. A printing test, a water resistance test, a light resistance test, a storage stability test, and evaluation thereof were performed in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

Example 5 (Preparation of Recording Liquid) Composition of Recording Liquid Used Amount (parts) Glycerin 16 Ethylene glycol 18 Styrene / Na styrenesulfonate (Molar ratio 7/3) Weight average molecular weight 4,800 3 Cinquasia Red B RT -195-D (manufactured by CIBA-GEIGY) 9 Deionized water 54 ─────────────────────────────── Total 100

Each of the above components was placed in a stainless steel container and pulverized for 40 hours using a sand grinder together with 152 parts of glass beads having an average diameter of 0.5 mm.
After diluting and stirring the obtained liquid with 127 parts of ion-exchanged water, Pressure filtration was performed using a 5C filter paper, and the liquid obtained here was used as a recording liquid. A printing test, a water resistance test, a light resistance test, a storage stability test, and evaluation thereof were performed in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

Comparative Example 1 (Preparation of recording liquid) In Example 1, Cinquasia Re
A liquid obtained by preparing a recording liquid in the same manner as in Example 1 except that dimethylquinacridone pigment (PR-122) was used instead of using dB RT-195-D was used as a recording liquid. A printing test, a water resistance test, a light resistance test, a storage stability test, and evaluation thereof were performed in the same manner as in Example 1.
The evaluation results are shown in Table 1 below.

COMPARATIVE EXAMPLE 2 (Preparation of Recording Solution)
A liquid obtained by adjusting a recording liquid in the same manner as in Example 1 except that a 1: 1 mixture of dichloroquinacridone pigment and unsubstituted quinacridone pigment was used instead of using DB RT-195-D was recorded. Liquid. A printing test, a water resistance test, a light resistance test, a storage stability test, and evaluation thereof were performed in the same manner as in Example 1. The evaluation results are shown in Table 1 below.

[0030]

[Table 1]

[Brief description of the drawings]

FIG. 1 is an X-ray diffraction diagram of a solid solution of dichloroquinacridone (substituted type) and unsubstituted quinacridone (RT-195-D).

FIG. 2 is an X-ray diffraction diagram of a blend of dichloroquinacridone (substituted type) and unsubstituted quinacridone.

Claims (3)

[Claims] In a recording liquid containing a mixture of two or more pigments in an aqueous medium, the mixture of the pigments has an X-ray diffraction peak at a position different from that obtained by simply physically mixing the same component pigment. A recording liquid characterized by being a solid solution of a pigment. 2. The recording liquid according to claim 1, wherein the pigment solid solution is a solid solution of dichloroquinacridone and unsubstituted quinacridone. 3. The ink jet recording liquid according to claim 1, wherein