JP2005029738A - Method for manufacturing organic pigment dispersion - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing pigment dispersion having high brightness, clarity, coloring power and a stable viscosity characteristic. <P>SOLUTION: This method for manufacturing pigment dispersion comprises grinding and dispersing a needle-like coarse pigment with a resin or a mixture of a resin and an organic solvent into a fine pigment of a mean particle diameter of a longitudinal length of 10 to less than 100 nm using a twin roll, wherein the needle-like coarse pigment is selected from phthalocyanine blue or phthalocyanine green and has an aspect ratio of ≥3 with the mean particle diameter of the longitudinal length of >100 nm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing an organic pigment dispersion in which organic pigment particles are finely and uniformly dispersed in a vehicle containing a resin or a mixture of a resin and an organic solvent and have high brightness, sharpness, and coloring power. .

As a method for producing a fine organic pigment dispersion, coarse and irregular coarse organic pigment particles are refined by a pigmentation process such as an acid pasting method, an acid slurry method, a salt milling method, and then used as a resin, a solvent, etc. A method of dispersing is common.
However, in these methods, since a drying step is required for pigmentation, the organic pigment particles cause strong dry aggregation, and it often takes a lot of energy and time to loosen and disperse the aggregation. In addition, it is often difficult to disperse finely and uniformly, and it is often difficult to obtain an organic pigment dispersion having high brightness, sharpness, and coloring power.

  A dry pulverization method using a ball mill, an attritor, a vibration mill, or the like can also be used in the pigmentation step for obtaining fine organic pigment particles. The dry pulverization method does not require a drying step and is a useful method in that there is no concern about dry aggregation. However, organic pigment particles often aggregate in the pulverization step, and this aggregation is loosened and dispersed. It takes a lot of energy and time.

Patent Document 1 discloses a technique in which organic pigment particles refined by a dry pulverization method are pigmented in an oil vehicle to obtain a dispersion.
JP 2001-323182 A

  The present invention provides a method for producing a phthalocyanine blue or phthalocyanine green pigment dispersion that can be dispersed finely and uniformly without requiring much energy and time.

  The present invention provides a method for producing a phthalocyanine blue or phthalocyanine green pigment dispersion in which pigments do not aggregate in a drying step or a pulverizing step.

As a result of diligent efforts, the present inventors have solved the problems of the prior art and have obtained an invention that solves the above problems.
That is, the present invention provides a needle-like crude pigment having an aspect ratio selected from phthalocyanine blue or phthalocyanine green of 3 or more and an average particle diameter of longer than 150 nm in the presence of a resin or a mixture of a resin and an organic solvent. Further, the present invention relates to a method for producing a pigment dispersion characterized by using two rolls to disperse the fine pigment having a long average particle diameter of less than 10 to 100 nm while being ground.

  The phthalocyanine blue or phthalocyanine green dispersion produced by the method of the present invention is not only used as a colorant for inks, paints, plastics, etc., but also for color filter resist inks and ink jet inks due to the above-mentioned excellent characteristics. By using it, good characteristics can be realized.

  In the present invention, when the acicular particles are pulverized by grinding, the vehicle is quickly and effectively adsorbed on the active surface exposed by the destruction of the particles, so that the fine phthalocyanine blue or phthalocyanine green pigment particles are obtained. It becomes possible to disperse stably without agglomeration.

In addition, most of the fine phthalocyanine blue or phthalocyanine green pigment particles obtained by grinding at the time of dispersion are spherical, square, and rice grains having an aspect ratio of 2 or less obtained by a conventional pigmentation method such as a salt milling method. Rather, many particles have an elongated shape with an aspect ratio of about 2 to 5 while being fine.
Such fine and elongated particles cannot be obtained by the method of the present invention when a crude pigment having an aspect ratio of 2 or less is used, and a needle-like crude pigment having an aspect ratio of 3 or more is obtained. It can be obtained by using.

  In the present invention, fine and elongated pigment particles different from phthalocyanine blue or phthalocyanine green pigment particles produced by the conventional pigmentation method are stably dispersed in the vehicle. The dispersion can be provided with high brightness, tinting strength, and stable viscosity characteristics.

  According to the present invention, a phthalocyanine blue or phthalocyanine green pigment dispersion having high brightness, sharpness, coloring power and stable viscosity characteristics can be obtained.

  The acicular crude phthalocyanine blue or phthalocyanine green pigment used in the present invention has an aspect ratio of 3 or more and a long average particle diameter of more than 100 nm is not particularly limited. I. Pigment blue 15: 6, C.I. I. Pigment green 36, C.I. I. Good results are obtained when CI Pigment Green 7 is used. Moreover, you may mix and use 2 or more types of pigments as needed.

  In the present invention, in addition to using two rolls, a pigment dispersion may be produced by performing a trituration and dispersion process using another apparatus as necessary. There are no particular restrictions on the apparatus used for the other milling and dispersing processes, but in the milling process, as in the case of the two rolls, the needle-like crude organic pigment particles are efficiently used with a strong impact force and shearing force. It is preferable that the particles can be finely pulverized and refined. In the dispersion step, it is preferable that the vehicle can be adsorbed quickly and effectively on the active surface exposed by the destruction of the needle-like particles by grinding.

Moreover, you may perform a grinding | pulverization and dispersion | distribution process in the state filled with inert gas, such as a pressure reduction state, a pressurization state, or nitrogen gas as needed.

  In the present invention, the organic solvent used when performing the grinding and dispersing step with two rolls is not particularly limited, but benzene, toluene, xylene, ethylbenzene, chlorobenzene, nitrobenzene, aniline, pyridine, quinoline, tetrahydrofuran. , Dioxane, methanol, ethanol, isopropanol, n-propanol, isobutanol, n-butanol, ethylene glycol, diethylene glycol, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, propylene glycol, propylene glycol glycol monomethyl ether Acetate, ethyl acetate, isopropyl acetate, butyl acetate, hexane, heptane, octane, nonane, decane, un Kang, dodecane, cyclohexane, methylcyclopentane f Sasan, halogenated hydrocarbons, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, dimethylformamide, dimethyl sulfoxide, N- methylpyrrolidone. Moreover, you may mix and use 2 or more types of solvents as needed.

  In the present invention, the boiling point of the organic solvent used when performing the grinding and dispersing step with two rolls or the like is not particularly limited, but is preferably 50 to 170 ° C.

  In the present invention, there are no particular restrictions on the resin used when performing the grinding and dispersing process with two rolls or the like, but rosin, rosin derivatives, rosin-modified maleic acid resins, rosin-modified phenolic resins, rubber derivatives, proteins Derivatives, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, polyvinyl acetate, epoxy resin, acrylic resin, maleic acid resin, styrene resin, styrene-maleic acid copolymer resin, butyral resin, polyester resin, melamine resin, phenol resin , Polyurethane resins, polyamide resins, polyimide resins, alkyd resins, rubber resins, celluloses, benzoguanamine resins, urea resins, and oligomers and monomers of the above resins.

  In the present invention, the addition amount of the resin used when performing the grinding and dispersing step with two rolls or the like is not particularly limited, but is preferably 10 to 90 parts by weight with respect to 100 parts of the pigment.

  In the present invention, the softening point of the resin used when performing the grinding and dispersing process with two rolls or the like is not particularly limited, but is preferably 40 to 180 ° C.

  In the present invention, before or during the process of grinding and dispersing with two rolls or the like, for the purpose of promoting the refinement of pigment particles, or for the purpose of preventing the formation of other crystal forms due to the crystal dislocation of the pigment. A pigment derivative may be added. The pigment derivative to be added is not particularly limited, but preferably has the same skeleton as the pigment to be ground and dispersed. Further, as a substituent, a sulfonic acid group and a sulfonic acid base, a sulfonic acid amide are used. And those having a phthalimidomethyl group are more preferred.

  In the present invention, an additive such as a surfactant may be added as necessary before or during the step of grinding and dispersing with two rolls.

  In the present invention, a pigment dispersion may be produced by performing an additional dispersion step as necessary after the step of grinding and dispersing with two rolls or the like. In this additional dispersion step, additives such as an organic solvent, a resin, a pigment derivative, and a surfactant may be added as necessary.

  Although there is no restriction | limiting in particular about the apparatus used for an additional dispersion | distribution process, Stirring type dispersers, such as a bead mill, can be used.

  EXAMPLES Next, although an Example and a comparative example demonstrate this invention concretely, this invention is not limited to a following example. In addition, the part in an Example shows a mass part.

A needle-like crude C.I. having an aspect ratio of 3 to 4 and an average particle diameter of a major axis of 200 to 300 nm I. A mixture of 70 parts of Pigment Green 36 pigment and 30 parts of acrylic resin was mixed well in advance, and then passed through a two-roll mill and kneaded to obtain a sheet. The sheet was folded into several sheets and passed through a two-roll mill again.
After repeating this process 20 times, it was pulverized by a pulverizer to obtain a color chip.
After 25 parts of the obtained color chip and 40 parts of the coating solvent were mixed and dispersed by a bead mill, 35 parts of the coating solvent was added and further dispersed to obtain a liquid pigment dispersion composition.
This liquid pigment dispersion composition was applied to a glass substrate and dried in an oven to obtain a coating film.
The gloss, haze value, and brightness of the obtained coating film were evaluated. Further, the viscosity of the liquid pigment dispersion composition was evaluated.
The evaluation results are shown in Table 1.

[Comparative Example 1]
The acicular crude C.I. used in Example 1 I. Pigment Green 36 pigment 17.5 parts, acrylic resin 7.5 parts and paint solvent 40 parts are mixed and dispersed in a bead mill, then paint solvent 35 parts is added and dispersed further to form a liquid pigment dispersion composition I got a thing.
The liquid pigment dispersion composition was evaluated for gloss, haze value, brightness and viscosity in the same manner as in Example 1. The evaluation results are shown in Table 1.

[Comparative Example 2]
The acicular crude C.I. used in Example 1 I. Pigment Green 36 pigment was refined by a salt milling method, and the resulting refined pigment was subjected to two-roll mill dispersion and bead mill dispersion in the same manner as in Example 1 to obtain a liquid pigment dispersion composition.
The liquid pigment dispersion composition was evaluated for gloss, haze value, brightness and viscosity in the same manner as in Example 1. The evaluation results are shown in Table 1.

A needle-like crude C.I. having an aspect ratio of 4 to 5 and an average particle diameter of major axis of 300 to 600 nm. I. A mixture of 70 parts of Pigment Blue 15: 6 pigment and 30 parts of acrylic resin was mixed well in advance, and then kneaded through a two-roll mill to obtain a sheet. The sheet was folded into several sheets and passed through a two-roll mill again.
After repeating this process 20 times, it was pulverized by a pulverizer to obtain a color chip.
After 25 parts of the obtained color chip and 40 parts of the coating solvent were mixed and dispersed by a bead mill, 35 parts of the coating solvent was added and further dispersed to obtain a liquid pigment dispersion composition.
This liquid pigment dispersion composition was applied to a glass substrate and dried in an oven to obtain a coating film.
The gloss, haze value, and brightness of the obtained coating film were evaluated. Further, the viscosity of the liquid pigment dispersion composition was evaluated.
The evaluation results are shown in Table 2.

[Comparative Example 3]
The acicular crude C.I. used in Example 1 I. Pigment Blue 15: 6 17.5 parts of pigment, 7.5 parts of acrylic resin, and 40 parts of solvent for paint are mixed and dispersed with a bead mill. A body composition was obtained.
The liquid pigment dispersion composition was evaluated for gloss, haze value, brightness and viscosity in the same manner as in Example 2. The evaluation results are shown in Table 2.

[Comparative Example 4]
Needle-like crude C.I. used in Example 2 I. Pigment Blue 15: 6 pigment was refined by a salt milling method, and the resulting refined pigment was subjected to two roll mill dispersion and bead mill dispersion in the same manner as in Example 2 to obtain a liquid pigment dispersion composition. .
The liquid pigment dispersion composition was evaluated for gloss, haze value, brightness and viscosity in the same manner as in Example 2. The evaluation results are shown in Table 2.

Claims (1)

A two-roll roll of acicular crude pigment having an aspect ratio of 3 or more selected from phthalocyanine blue or phthalocyanine green in the presence of a resin or a mixture of a resin and an organic solvent. A method for producing a pigment dispersion, wherein the dispersion is carried out by grinding into a fine pigment having an average particle diameter of 10 to 100 nm.