TWI500710B - Pigment dispersions for color filters - Google Patents

Description

Pigment dispersion for color filters

The present invention relates to a pigment dispersion, and more particularly to a pigment dispersion for a color filter used in the production of a color filter used in a color liquid crystal display device or the like.

In general, in a mixture of water, a solvent, a resin, or the like (a color developing material), it is difficult to stably disperse the pigment. This still results from pigment particles which are once dispersed in the mixture, and there is a tendency for aggregation in the mixture. If the pigment is agglomerated, the dispersibility of the mixture (pigment dispersion) is lowered, and the viscosity is increased. Moreover, the performance of the coating film such as a color filter using the pigment dispersion is lowered.

In recent years, in particular, there has been a strong demand for performance improvement of color filters, and it is necessary to achieve high contrast of color filters and high concentration of pigments (high content). However, the pigment dispersion for a color filter which is generally used in the past cannot avoid the aggregation of the pigment particles as described above, and it is possible to prevent an increase in viscosity due to a high concentration of the pigment and a decrease in storage stability. It becomes difficult, and it is difficult to improve the contrast of the color filter.

In order to solve such problems, it is proposed to use a pigment dispersion liquid or the like of various dispersants (for example, refer to Patent Documents 1 and 2), but the above problems have not been solved.

[Patent Document 1] JP-A-2007-284642

[Patent Document 2] JP-A-2008-81732

The present invention has been made in view of the above problems, and an object thereof is to provide a pigment dispersion containing a high content (high concentration) of a fine pigment and having excellent dispersion stability while achieving high contrast of a color filter.

The present inventors have attained the present invention in order to solve the above problems and have carefully studied the results. That is, the gist of the present invention is as follows.

(1) A pigment dispersion for a color filter comprising a pigment dispersion of a fine pigment, a dispersant, a dispersion resin, and a solvent, wherein the dispersant contains an acid value of 2 mgKOH/g or more and an amine price. The compound of 0 mgKOH/g and the compound having an amine price of 10 mgKOH/g or more and an acid value of 0 mgKOH/g each contain at least one kind of compound, or a compound having an amine value of 10 mgKOH/g or more and an acid value of 2 mgKOH/g or more. .

(2) The pigment dispersion for a color filter according to (1), wherein the fine pigment is finely refined by a salt milling treatment.

(3) The pigment dispersion for a color filter according to (1), wherein the finely divided pigment has an average particle diameter of 10 to 50 nm.

(4) The pigment dispersion for a color filter according to any one of (1) to (3), wherein the solvent is a high boiling point solvent having a boiling point of 180 ° C or higher.

(5) The pigment dispersion for a color filter according to any one of (1), wherein the fine pigment is treated with a surface treatment agent.

In the pigment dispersion of the present invention, the fine pigment particles having a high content (high concentration) are uniformly finely dispersed, and the pigment particles are excellent in dispersion stability over a long period of time (long-term dispersion stability). Therefore, the change in the temporal characteristics of the pigment dispersion is effectively prevented, and it is also applicable to a coating film for a color filter having a uniform coloring density over a long period of time (hereinafter, simply referred to as "coating film") The formation of a coating film having a uniform film thickness and the like can effectively prevent color unevenness and density unevenness from occurring in the formed coating film. Further, since a high content of finely divided pigment particles is finely dispersed, the pigment is excellent in color developability, and is suitable for formation of a coating film having high lightness. Further, the comparison of the coating films for color filters can be made extremely excellent.

[Best Practice for Carrying Out the Invention]

A pigment dispersion for a color filter of the present invention (hereinafter sometimes referred to simply as "pigment dispersion"), which is a pigment dispersion containing a fine pigment, a dispersant, a dispersion resin, and a solvent, and is characterized by the aforementioned The dispersant contains the defined compound.

The dispersant is a component that contributes to the improvement of the dispersibility of the pigment particles in the pigment dispersion. In the present invention, the dispersant contains a compound having an acid value of 2 mgKOH/g or more and an amine value of 0 mgKOH/g (hereinafter sometimes referred to as an acid value dispersant) and an amine value of 10 mgKOH/g or more and an acid value of 0 mgKOH/ Each of the compounds of g (hereinafter sometimes referred to as an amine valence dispersant) contains at least one kind of mixture, or a compound having an amine value of 10 mgKOH/g or more and an acid value of 2 mgKOH/g or more (hereinafter, sometimes referred to as amphoteric) Dispersant). Further, the above-mentioned compound having an amine value of 10 mgKOH/g or more and an acid value of 2 mgKOH/g or more means a compound having a basic group (amino group) and an acidic group in one molecule, and the amine value and the acid value have The aforementioned values.

By disposing the dispersant in such a configuration, it is possible to make the dispersibility and dispersion stability of the pigment particularly excellent. Further, by using the dispersant, the dispersant adheres (adsorbs) to the surface of the fine pigment particles added to the dispersant dispersion liquid in the microdispersion step of the production method to be described later, and the pigment particles can be used. The dispersibility in the dispersant dispersion is excellent. Thereby, the microdispersion treatment in the microdispersion step can be efficiently performed, and the productivity of the pigment dispersion can be made particularly excellent, and at the same time, the finely dispersed state of the fine pigment particles in the finally obtained pigment dispersion is maintained. It can make its long-term dispersion stability become particularly excellent.

The dispersing agent used in the present invention is an acid value dispersing agent having an acid value as defined above (amine price: 0 mgKOH/g) and an amine valence dispersing agent having a predetermined amine value (acid value: 0 mgKOH/g). Each of the compounds containing at least one of the mixtures, or the amine and the acid having a predetermined value.

Thereby, an effect of an acid-valent dispersant (or an acidic group) which exhibits an effect of reducing aggregation of the pigments, and an amine-valent dispersant (or a basic group (amino group) which stabilizes the dispersion state of the pigment can be obtained. Both of the effects produced are satisfied, and in particular, the dispersion stability of the pigment in the dispersion in the fine pigment can be made particularly excellent.

Further, by using a mixture of an acid value dispersant and an amine valence dispersant, or a compound having an amine value and an acid value having a predetermined value, the following effects can be obtained. In other words, when the pigment dispersion is produced by a method described later, the dispersant is efficiently adhered (adsorbed) to the surface of the fine pigment particles added to the dispersion liquid dispersion in the fine dispersion step. The dispersibility of the fine pigment particles in the dispersion of the dispersant is excellent. Thereby, the microdispersion treatment in the microdispersion step can be efficiently performed, and the productivity of the pigment dispersion can be made particularly excellent, and at the same time, the finely dispersed state of the fine pigment particles in the finally obtained pigment dispersion is maintained. The long-term dispersion stability of the pigment dispersion system is particularly excellent. Further, the production method described later has a preliminary dispersion step of dispersing a dispersion liquid containing a dispersant and a dispersion resin in a solvent by stirring a mixture containing a dispersant and a dispersion resin and a solvent before the fine dispersion treatment of the pigment. In such a method, by using a mixture of an acid valence dispersant and an amine valence dispersant, or a compound having an amine value and an acid value having a predetermined value, the aggregation of the dispersant is surely prevented, and the dispersion of the fine pigment can be stabilized. Sex is particularly outstanding.

[acid value dispersant]

As described above, the acid value dispersing agent used in the present invention is a compound containing an acid value of 2 mgKOH/g or more. The acid value of the acid value dispersant (the acid value in the conversion of the solid content) is not particularly limited as long as it is within the above range, but is preferably 5 to 370 mgKOH/g, more preferably 20 to 270 mgKOH/g, and 30 to 135 mgKOH. /g is even better. When the acid value of the acid value dispersant is within the above range, the synergistic effect by the amine-valent dispersant is more prominently exhibited, and the dispersion stability of the pigment is particularly excellent. The acid value of the dispersant can be determined, for example, by the method according to DIN EN ISO 2114. Further, the acid value dispersing agent does not have a predetermined amine price, that is, the amine value is 0 mgKOH/g. In addition, when the amine value is measured by the method according to DIN 16945 or the like, the amine valence is substantially 0 mg KOH/g when the amine valence is substantially insufficient to achieve the effect of the amine group depending on the measurement error or the like.

The acid value dispersing agent is not particularly limited as long as it has the above-mentioned acid value, but a compound having a polyester chain is preferably used because of high adsorption property to the pigment. Specific examples of the acid value dispersing agent which can be used in the present invention include Disperbyk P104, Disperbyk P104S, Disperbyk 220S, Disperbyk 110, Disperbyk 111, Disperbyk 170, Disperbyk 171, Disperbyk 174, Disperbyk 2095 (above, BYK-Chemie Japan) )); EFKA 5010, EFKA 5065, EFKA 5066, EFKA 5070, EFKA 7500, EFKA 7554 (above, Ciba Japan); SOLSPERSE 3000, SOLSPERSE 16000, SOLSPERSE 17000, SOLSPERSE 18000, SOLSPERSE 36000, SOLSPERSE 36600, SOLSPERSE 41000 (above, manufactured by Lubrizol Co., Ltd.).

[Amine Price Dispersant]

As described above, the amine-valent dispersant used in the present invention is a compound containing an amine having a valence of 10 mgKOH/g or more. The amine value of the amine-valent dispersant (the amine value in the conversion of the solid content) is not particularly limited as long as it is within the above range, but is preferably 5 to 200 mgKOH/g, more preferably 30 to 170 mgKOH/g, and 40 to 130 mgKOH. /g is even better. When the amine value of the amine-valent dispersant is a value within the above range, the synergistic effect by the acid-valent dispersant is more prominently exhibited, and the dispersion stability of the pigment is particularly excellent. The amine valence of the dispersant can be determined, for example, by the method according to DIN 16945. Further, the amine valence dispersant does not have a predetermined acid value, that is, the acid value is 0 mgKOH/g. In addition, when the acid value is measured by the method according to DIN EN ISO 2114 or the like, the acid value can be substantially allowed when the acid value is substantially insufficient to achieve the effect of the acidic group according to measurement error, hydrolysis, or the like. 0 mg KOH / g.

The amine-valent dispersant is not particularly limited as long as it has the above-mentioned amine price. However, it is preferred to use a compound having a polyester chain because of high adsorption property to the pigment. Specific examples of the amine valence dispersant which can be used in the present invention include Disperbyk 102, Disperbyk 160, Disperbyk 161, Disperbyk 162, Disperbyk 163, Disperbyk 164, Disperbyk 166, Disperbyk 167, Disperbyk 168, Disperbyk 2150, Disperbyk LPN6919, Disperbyk 9075 , Disperbyk 9077 (above, BYK-Chemie); EFKA 4015, EFKA 4020, EFKA 4046, EFKA 4047, EFKA 4050, EFKA 4055, EFKA 4060, EFKA 4080, EFKA 4300, EFKA 4330, EFKA 4340, EFKA 4400, EFKA 4401, EFKA 4402, EFKA 4403, EFKA 4800 (above, Ciba Japan); AJISPER PB711 (above, Ajinomoto Fine-Techno); Anti-Terra-205 (above, BYK-Chemie Japan) ))).

When the content of the acid value dispersing agent in the pigment dispersion is set to X _A [wt%], and the content of the amine valence dispersing agent in the pigment dispersion is set to X _B [wt%], it corresponds to 0.1 ≦ X _A / X _B ≦ The relationship of 1 is better, and the relationship of 0.15 ≦ X _A / X _B ≦ 0.5 is better. By conforming to such a relationship, the synergistic effect by the acid-valent dispersant and the amine-valent dispersant is more prominently exhibited, and the dispersion stability of the pigment can be made particularly excellent.

Further, the acid value of the acid value dispersing agent is determined to be AV [mgKOH/g], the amine value of the amine-valent dispersing agent is determined to be BV [mgKOH/g], and the content of the acid-valent dispersing agent is set to X _A [wt% When the content of the amine-valent dispersant is set to X _B [wt%], the relationship of 0.01 ≦ (AV × X _A ) / (BV × X _B ) ≦ 1.9 is preferable, which is in accordance with 0.10 ≦ (AV × X). _{The relationship of A} ) / (BV × X _B ) ≦ 0.95 is better. By conforming to such a relationship, the synergistic effect by the acid-valent dispersant and the amine-valent dispersant is more prominently exhibited, and the dispersion stability of the pigment can be made particularly excellent.

[amphoteric dispersant]

As described above, the amphoteric dispersant used in the present invention is a compound having an amine value of 10 mgKOH/g or more and an acid value of 2 mgKOH/g or more. The acid value (acid value in terms of solid content conversion) is not particularly limited as long as it is within the above range, but 2 to 15 mgKOH/g is preferred. In addition, the amine value (the amine value in terms of solid content) is not particularly limited as long as it is within the above range, but 10 to 35 mgKOH/g is preferred. The acid value and the amine price can each be obtained according to the method of DIN EN ISO 2114 and DIN 16945.

The acid value and the amine value of the amphoteric dispersant are within the above-mentioned range, and the effect of the same as or higher than that of the acid-valent dispersant and the acid-valent dispersant can be exhibited more remarkably, and the dispersion stability of the pigment can be made particularly excellent. The adhesion of the pigment dispersion is more effectively inhibited.

In particular, the use of the amphoteric dispersant tends to have a high change in long-term dispersion stability compared to the case of using a mixture of an acid-valent dispersant and an amine-valent dispersant, and the viscosity-increasing of the pigment dispersion can be further reduced.

The amphoteric dispersant is not particularly limited as long as it has the above-mentioned acid value and amine value. However, it is preferred to use a compound having a polyester chain because of high adsorption property to the pigment. Specific examples of the amine-valent dispersant which can be used in the present invention include HINOACT T-8000 and HINOACT T-8000E (above, manufactured by Kawasaki Fine Chemicals Co., Ltd.), and the like may be selected from one or two kinds selected from the above. Use above. If necessary, an acid valence dispersant and an amine valence dispersant may be used in combination.

The pigment to be used in the present invention is not particularly limited, and examples thereof include an azo pigment, a phthalocyanine pigment, an anthraquinone pigment, a quinacridone pigment, an indigo pigment, a dioxazine pigment, and an anthraquinone. Condensed polycyclic rings of pigments, perinone pigments, isoindolinone pigments, isoindan pigments, metal complex pigments, quinophthalone pigments, dioxopyrrolopyrrole pigments, etc. It is a pigment or the like.

More specifically, for example, CI Pigment Red 254, CI Pigment Red 177, CI Pigment Orange 36, CI Pigment Green 58, CI Pigment Green 7, CI Pigment Yellow 150, CI Pigment Yellow 139, CI Pigment Yellow 138, CI Pigment Blue 15:6, at least one selected from CI Pigment Violet 23, CI Pigment Orange 38, CI Pigment Orange 43, CI Pigment Orange 71.

These pigments may be used singly or in combination, but it is preferred to use a sulfonic acid group-containing derivative of a pigment (for example, refer to JP-A-2007-186681), or a pigment having phthalic acid. A derivative of a formazan group, which improves the dispersibility of the pigment and the like.

The content of the pigment (including the main pigment and the sub-pigment) in the pigment dispersion is preferably 5 wt% or more, more preferably 8 to 25 wt%. As described above, the content of the pigment is sufficiently high (high content), and for example, the color development density of the coating film formed by using the pigment dispersion can be made particularly high. Further, the amount of the pigment dispersion required for forming a coating film having a predetermined film thickness and color density can be reduced, which is advantageous from the viewpoint of resource saving. Further, since the amount of volatilization of the solvent at the time of forming the coating film can be suppressed, the burden on the environment can be reduced.

In the fine pigment of the present invention, the pigment can be obtained by grinding according to a solvent salt milling treatment or a dry honing method (dry honing without using a solvent).

The solvent salt milling treatment refers to a method of honing a pigment using a solvent, specifically, as described below.

First, a mixture containing a fine pigment (hereinafter referred to as "crude pigment"), a water-soluble inorganic salt (grinding agent), and a binder is kneaded by a kneading machine or the like according to a predetermined method. A kneaded material containing a fine pigment is obtained. (Hereinafter, this kneaded material is sometimes referred to as a thick liquid).

The water-soluble inorganic salt to be used in this case is, for example, sodium sulfate (sodium sulfate) or salt (sodium chloride), and the content thereof is 5.5 μm or less, and the content of the particle diameter of 10.0 μm or more is 5% by volume or less. Excellent fine pigments which are uniformly and highly refined can be obtained. Further, as the binder to be used, a water-soluble organic solvent can be widely used, and examples thereof include diethylene glycol (DEG), ethylene glycol, and polyethylene glycol.

Next, the thick liquid in which the above-mentioned original pigment was refined was taken out, and it was transferred to the temperature-regulated tank, and the thick liquid was dispersed in the deionized water. The dispersion was pumped to a filter press and filtered. After the dispersion was completely transferred, it was washed with water to obtain a fine pigment paste. The water-washed pigment paste is transferred to a dryer and then dried to obtain a dried mass of the fine pigment, which is pulverized to obtain a fine pigment.

Dry honing means a method of honing without using a solvent, specifically, as described below. For example, a raw material and a grinding agent are added to a high-speed mixer, and the mixture is stirred and mixed. At this time, a small amount of a water-soluble solvent (for example, DEG) may be added as necessary. Then, after cooling, the mixture in which the refinement of the original pigment is completed (hereinafter, the kneaded material is sometimes referred to as a thick liquid) is taken out and transferred to the tank. The mixture is mixed with deionized water in the tank to disperse the thick liquid. The dispersion was completely transferred to a filter press for filtration, and then washed with water to obtain a fine pigment paste. The water-washed pigment paste was transferred to a dryer and dried to obtain a dried cake of fine pigment. The dried block is pulverized by a pulverizer, and the pulverized product is collected by a cyclone or the like to obtain a fine pigment. Further, the grounding agent used in the dry honing can be the same as that used in the above-described solvent salt milling treatment.

By the above respective methods, a uniform fine pigment having an average particle diameter of 10 to 50 nm can be easily obtained. However, in the case where the fineness of the pigment is particularly excellent, it is preferred to use a solvent salt milling treatment.

In the present invention, the surface of the finely colored pigment may be treated with a surface treatment agent. In the case where the pigment is refined as described above, a surface treatment agent is added to honing, and a surface treatment agent is applied to the surface of the fine pigment. Specifically, a method of adding a surface treatment agent and then honing it after honing without adding a surface treatment agent at a predetermined temperature and time may be mentioned. The processing time at this time is 20 to 120 minutes. Further, the amount of the surface treatment agent to be added is preferably 5 to 50 parts by weight, more preferably 10 to 30 parts by weight, per 100 parts by weight of the pigment component.

Further, among the plurality of pigments, when only a part of the pigment is subjected to surface treatment, it may be mixed with the above-mentioned surface treatment agent for treatment and untreated.

By treating the fine pigment in the surface treatment agent in this manner, it is possible to prevent re-aggregation of the fine pigment particles and to contain a pigment dispersion of a fine pigment treated with a surface treatment agent, and the long-term dispersion stability of the pigment is extremely high. The increase in viscosity is suppressed. Therefore, the color filter using the pigment dispersion is superior in comparison and is excellent.

The surface treatment agent is a resin or a compound which has an effect of preventing re-aggregation of the fine pigment particles, and is selected from the surface of the micronized pigment particles after being subjected to water removal to remove the grinding agent, dehydration, or the like in the above-described miniaturization treatment. By.

Specifically, an acrylic resin is preferably used. Examples of such an acrylic resin are those obtained by polymerization using a monomer selected from an alkyl acrylate such as acrylic acid, methacrylic acid, methyl acrylate or methyl methacrylate or an alkyl methacrylate. The molecular weight of the polymer is preferably from about 5,000 to 100,000. Specific examples of such an acrylic resin include, for example, RIPOXY SPC2000 (manufactured by Showa Polymer Co., Ltd.).

The dispersion resin has a function of improving the dispersibility of the pigment particles, and forms a part of the coating film during molding.

Examples of the dispersion resin used in the present invention include alginic acid, polyvinyl alcohol, hydroxypropyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, styrene-acrylic resin, and styrene. -Acrylic-acrylate resin, styrene-maleic acid resin, styrene-maleic acid half ester resin, methacrylic acid-methacrylate resin, acrylic acid-acrylate resin, isobutylene-maleic acid resin, rosin modified The maleic acid resin, polyvinylpyrrolidone, gum arabic starch, polyallylamine, polyvinylamine, polyethyleneimine, or the like may be used in combination of one or more selected from the above. Among these, an acrylic resin can also be used as the surface treatment agent mentioned above.

The content of the dispersion resin in the pigment dispersion is not particularly limited, but is preferably from 1 to 20 parts by weight, more preferably from 5 to 15.5 parts by weight, per 100 parts by weight of the pigment component.

The solvent is in the pigment dispersion and has a function as a dispersion medium for dispersing the pigment. Further, the solvent, as in the method for producing a pigment dispersion described later, has a function as a solvent for dissolving the dispersion resin in the dispersion liquid dispersion.

As the solvent to be used in the present invention, either a nonaqueous solvent or an aqueous solvent can be used, but a water-soluble solvent is preferably used. The use of a water-soluble solvent as a solvent tends to make the dispersibility of the pigment as described above particularly excellent. As the water-soluble solvent, a hydrophilic solvent can be used. Specifically, for example, a liquid having a solubility of 3 g or more with respect to 100 g of water at 25 ° C can be used.

As the water-soluble solvent, a compound having a functional group having a high hydrophilicity such as a hydroxyl group or a compound having a polyglycol skeleton or the like is generally suitably used.

Specific examples of the water-soluble solvent include alkyl alcohols having 1 to 4 carbon atoms such as ethanol, methanol, butanol, propanol, and isopropanol, ethylene glycol monomethyl ether, and ethylene glycol monoethyl ether. , ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, Ethylene glycol mono-iso-propyl ether, diethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol Mono-n-butyl ether, ethylene glycol mono-t-butyl ether, diethylene glycol mono-t-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, Propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol single -n-propyl ether, dipropylene glycol mono-iso-propyl ether, propylene glycol mono-n-butyl ether, dipropylene glycol mono-n-butyl ether, glycol ethers, formamide, acetamide, Dimethyl hydrazine, sorbitan, sorbitan, glycerol acetate, diacetin, triacetate The oil ester, the cyclodextrin, etc. can be used in combination of one or two or more selected from the above.

In the present invention, a high-boiling water-soluble organic solvent having a boiling point of 180 ° C or higher can be used for the purpose of preventing a change in viscosity due to evaporation of a solvent during storage of the pigment dispersion.

Specific examples of the water-soluble organic solvent having a boiling point of 180 ° C or higher include ethylene glycol, propylene glycol, diethylene glycol, pentamethylene glycol, trimethyl diol, and 2-butene-1,4-diol. 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, tripropylene glycol monomethyl ether, dipropylene glycol monoethyl glycol, dipropylene glycol monoethyl ether, Dipropylene glycol monomethyl ether, dipropylene glycol, triethylene glycol monomethyl ether, tetraethylene glycol, triethylene glycol, diethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol Alcohol monomethyl ether, tripropylene glycol, polyethylene glycol having a molecular weight of 2000 or less, 1,3-propanediol, isopropyl glycol, isobutylene glycol, 1,4-butanediol, 1,3-butanediol, 1 , 5-pentanediol, 1,6-hexanediol, glycerin, intraerythritol, pentaerythritol, and the like may be used in combination of one or more selected from the above.

Thereby, the dispersion state of the dispersing agent can be easily made more suitable, and the long-term dispersion stability of the pigment particles in the pigment dispersion can be made particularly excellent. Further, even when the content of the pigment in the pigment dispersion is increased, the long-term dispersion stability of the pigment can be sufficiently excellent.

Further, when the pigment dispersion is produced by the method described later, the pigment dispersion can be efficiently produced, and the productivity of the pigment dispersion can be made particularly excellent.

As described above, in the present invention, a water-soluble solvent is preferably used as the solvent, but a water-insoluble solvent may also be used.

As the water-insoluble solvent, for example, an ester solvent, an ether solvent, a ketone solvent or the like can be used.

Examples of the water-insoluble ester solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, isopropyl acetate, methyl propionate, 3-methoxybutyl acetate, and ethyl acetate. Alcohol acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, 3-methyl-3-methoxybutyl acetate, methyl monochloroacetate, ethyl monochloroacetate , butyl monochloroacetate, methyl acetate, ethyl acetate, butyl carbitol acetate, butyl lactate, ethyl-3-ethoxypropionate, ethylene glycol monobutyl Ether acetate, ethylene glycol monomethyl ether acetate, propyl acetate, and the like.

Examples of the water-insoluble ether solvent include ethylene glycol monohexyl ether, ethylene glycol-2-ethylhexyl ether, ethylene glycol phenyl ether, diethylene glycol-n-hexyl ether, and diethylene glycol. 2-ethylhexyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, dipropylene glycol propyl ether, propylene glycol methyl ether propionate, and the like.

Examples of the water-insoluble ketone solvent include methyl ethyl ketone, methyl isobutyl ketone, di isobutyl ketone, acetamidine acetone, isophorone, acetophenone, and cyclohexanone.

Further, in addition to the above, aromatic hydrocarbons such as toluene, xylene, and ethylbenzene may also be used.

The pigment dispersion of the present invention may contain a component other than the above-described fine pigment, dispersant, dispersion resin, or solvent. Examples of such a component include a pH adjuster, an antioxidant, an ultraviolet absorber, a preservative, an antifungal agent, and the like.

As described above, the pigment dispersion of the present invention can maintain the state in which the finely divided pigment is finely dispersed for a long period of time, and as a method for evaluating the state of microdispersion, the viscosity of the pigment dispersion can be measured, and the measured value is an index.

The measurement of the viscosity (dynamic viscosity) of the pigment dispersion can be carried out, for example, using an E-type viscometer (for example, RE-01 manufactured by Toki Sangyo Co., Ltd.), and in particular, it can be carried out in accordance with JIS Z8809.

The viscosity of the pigment dispersion at 25 ° C (viscosity (dynamic viscosity) measured using an E-type viscometer), 17 mPa. The following is better, 12mPa. s is better below. In this way, the viscosity (dynamic viscosity) of the pigment dispersion can be sufficiently low. For example, the efficiency of formation of the coating film can be particularly excellent, and variations in the thickness of the coating film can be effectively prevented. On the other hand, the viscosity of the pigment dispersion is too low, and for example, it may be difficult to make the film thickness of the coating film formed using the pigment dispersion sufficiently thick.

Further, in the environment of 40 ° C, the viscosity of the pigment dispersion at 25 ° C after 7 days of storage (the viscosity (dynamic viscosity) measured by the E-type viscometer) is preferably 1.3 or less, which is 1.1. The following is better. Further, the above-described rate of change is a value calculated from (measured value of viscosity after leaving for 7 days at 40 ° C) / (measured value of viscosity before standing).

In this way, the characteristics of the pigment dispersion can be changed to be sufficiently small (the durability of the pigment dispersion is excellent), and for example, the color unevenness when the coating film is formed by using the pigment dispersion can be reliably prevented over a long period of time. The occurrence of uneven concentration and the decrease in contrast.

The pigment dispersion as described above can be used for the formation of a coating film for a color filter or the like. As described above, in the pigment dispersion of the present invention, since the finely divided pigment particles are finely dispersed, excellent dispersion stability can be maintained over a long period of time, so that unevenness of fine pigment particles in the pigment dispersion can be prevented. The coating film formed using the pigment dispersion of the present invention is excellent in uniformity in film thickness, color unevenness, density unevenness, and the like can be reliably prevented. In particular, when used as a color filter, the value of the contrast is hardly lowered. Therefore, according to the pigment dispersion of the present invention, such a high-quality coating film can be stably formed over a long period of time.

The coating film, for example, by a bar coating, a spin coating, a roll coating, a slit coating, a brush coating, an offset printing, a gravure printing, or the like, the pigment dispersion It is supplied onto a substrate, and then, if necessary, dried (solvent treatment) to form a coating film of interest.

The pigment dispersion as described above can be produced, for example, by the following method. In a schematic manner, a dispersant dispersion (preparation dispersion step) in which a dispersant is dispersed in a solvent is obtained by stirring a mixture containing a dispersant, a dispersion resin, and a solvent, and a dispersion liquid is added to the obtained dispersant dispersion. The finely divided pigment is subjected to microdispersion treatment (fine dispersion step) by adding inorganic beads in a single stage or in multiple stages to obtain a pigment dispersion of the present invention. Hereinafter, each step will be described in detail.

In the preliminary dispersion step, a dispersant dispersion liquid in which a dispersant is dispersed in a solvent is prepared by stirring a mixture containing a dispersant, a dispersion resin, and a solvent. Thereby, the state in which the aggregation state of the dispersing agent is eliminated (dissolved) can be obtained. However, the acid-valent dispersant and the amine-valent dispersant used in the present invention originally have a property of being easily adsorbed by electricity, but as in the present embodiment, preliminary dispersion is carried out before the fine dispersion (fine dispersion step) of the pigment. In the step, the acid-valent dispersant and the amine-valent dispersant can be uniformly and stably adhered to the surface of the pigment particles in a state where the aggregation state is sufficiently eliminated, and the aggregation of the dispersants and the aggregation of the pigment particles can be reliably prevented. The dispersion stability of the pigment can be made particularly excellent. In this respect, the same applies to the use of the amphoteric dispersant.

In this step, by dispersing the dispersion resin together with the dispersant and the solvent, the dispersant and the dispersion resin are adhered to the surface of the fine pigment particles added to the dispersion liquid dispersion in the microdispersion step described later. The dispersibility in the dispersant dispersion of the pigment particles can be excellent. Thereby, the microdispersion treatment can be efficiently performed in the microdispersion step, and the productivity of the pigment dispersion can be made particularly excellent, and at the same time, the fine pigment particles in the finally obtained pigment dispersion can be maintained in a microdispersion state. Its long-term dispersion stability has become excellent.

The content of the dispersant in the dispersant dispersion prepared in this step (the total content of the plurality of dispersants) is not particularly limited, but is preferably 10 to 40% by weight, more preferably 12 to 32% by weight. When the content of the dispersant is a value within the above range, the effects described above are more prominently exhibited.

Further, the content of the dispersion resin in the dispersion liquid dispersion prepared in this step is not particularly limited, but is preferably 6 to 30% by weight, more preferably 8 to 26% by weight. When the content of the dispersion resin is within the above range, the effects described above are more prominently exhibited.

Further, the content of the solvent in the dispersion of the dispersant prepared in this step is not particularly limited, but is preferably 30 to 90% by weight, more preferably 40 to 80% by weight. When the content of the solvent is within the above range, the effects described above are more prominently exhibited.

The amount of the solvent to be used is not particularly limited, but it is usually 100 to 500 parts by weight, preferably 100 to 300 parts by weight, based on 100 parts by weight of the solvent of the pigment dispersion obtained in the last pigment dispersion. For better, it is better to be 100 to 200 parts by weight. When the amount of the solvent used is too small, it is difficult to uniformly disperse the fine particles of the fine particles in the microdispersion step described later. On the other hand, when the amount of the solvent used is too large, it is difficult to sufficiently increase the strength and the like of the film formed by using the pigment dispersion obtained at the end.

In this step, a mixture of the above components is stirred by using various agitators to obtain a dispersant dispersion. The agitator which can be used in this step may, for example, be a shaft or a two-shaft mixer such as Dispermill.

The stirring treatment time using the agitator is not particularly limited, but it is preferably 1 to 30 minutes, and 3 to 20 minutes is more preferable. In this way, the productivity of the pigment dispersion is sufficiently excellent, and the state of aggregation of the dispersant can be more effectively eliminated, and the dispersion stability of the fine pigment particles in the finally obtained pigment dispersion can be made particularly excellent.

Further, the number of rotations of the stirring blade which the agitator of this step has is not particularly limited, but 500 to 4000 rpm is preferable, and 800 to 3000 rpm is more preferable. In this way, the productivity of the pigment dispersion is sufficiently excellent, and the state of aggregation of the dispersant can be more effectively eliminated, and the dispersion stability of the fine pigment particles in the finally obtained pigment dispersion can be made particularly excellent. Further, it is possible to reliably prevent deterioration, modification, and the like due to heat or the like of the dispersion resin or the like.

Next, the finely divided pigment is added to the dispersion liquid dispersion obtained in the above step, and the inorganic beads are added in a single-stage or multi-stage to carry out a fine dispersion treatment (fine dispersion step).

In the microdispersion step, the addition of the inorganic beads may be carried out in a single stage or in multiple stages. However, by adding the inorganic beads in multiple stages, the efficiency of the micronization of the pigment can be made more excellent, and the finally obtained pigment can be obtained. The finely divided pigment particles in the dispersion are extremely uniformly dispersed and are stable. In particular, by using a mixture of an acid valence dispersant and an amine valence dispersant as defined above or an amphoteric dispersant, and by a method having a preliminary dispersion step and a multistage microdispersion step, the respective effects are multiplied. The dispersion stability of the fine pigment is imparted. When the pigment dispersion obtained in this manner is used, a coating film having more excellent lightness and contrast can be formed.

Further, in order to sufficiently exhibit the effects of the specific dispersant used in the present invention as described above, it is desirable to sufficiently carry out the dispersion treatment.

The following description relates to a method of adding inorganic beads in two stages, that is, a method of performing a first treatment using a first inorganic bead and a second treatment using a second inorganic bead in a microdispersion step, typically Description.

The inorganic beads (the first inorganic beads and the second inorganic beads) used in the present step may be formed of any inorganic material, and may be any material. However, as a suitable example of the inorganic beads, a suitable example is exemplified. Beads made of zirconia (for example, Toray ceram crushing ball (trade name), manufactured by Toray Industries, Inc.).

In the first treatment step, first, a fine pigment is added to the dispersion liquid dispersion prepared in the preliminary dispersion step, and the first inorganic fine beads having a predetermined particle diameter are used for the first treatment of primary dispersion. The first inorganic beads used in the first treatment are preferably larger than the second inorganic beads used in the second treatment. Thereby, the efficiency of fine dispersion of the finely divided pigment in the entire microdispersion step can be made excellent.

The average particle diameter of the first inorganic beads is not particularly limited, but is usually 0.5 to 3.0 mm, preferably 0.5 to 2.0 mm, more preferably 0.5 to 1.2 mm. When the average particle diameter of the first inorganic beads is within the above range, the efficiency of fine dispersion of the pigment in the entire microdispersion step can be excellent. On the other hand, when the average particle diameter of the first inorganic beads is less than the above-described lower limit, the efficiency of microdispersion of the finely divided pigment particles of the first treatment tends to decrease depending on the type of the pigment or the like. In addition, the average particle diameter of the first inorganic beads is more than the above-described upper limit value, and the efficiency of microdispersion of the pigment particles of the first treatment is relatively excellent, but the finely divided pigment particles of the second treatment are finely dispersed. The efficiency is lowered, and the efficiency of microdispersion of the finely divided pigment as a whole in the microdispersion step is lowered.

The amount of the first inorganic beads to be used is not particularly limited, but is preferably 100 to 600 parts by weight, more preferably 200 to 500 parts by weight, per 100 parts by weight of the dispersion liquid dispersion. The amount of the fine pigment to be added to the dispersant dispersion is not particularly limited, but is preferably 12 parts by weight or more, and more preferably 18 to 35 parts by weight, per 100 parts by weight of the dispersion liquid dispersion.

The first treatment can be carried out by stirring in a state in which the fine pigment and the first inorganic beads are added to the dispersion liquid dispersion using various agitators. Examples of the agitator that can be used in the first treatment include a MEDIA TYPE disperser such as a pear mill, or a shaft or biaxial mixer such as Dispermill. The stirring treatment time (the processing time of the first treatment) using the agitator is not particularly limited, but it is preferably 10 to 120 minutes, and more preferably 15 to 40 minutes. Thereby, the fine dispersion of the finely divided pigment can be efficiently performed without lowering the productivity of the pigment dispersion.

Further, the number of rotations of the stirring blade included in the mixer of the first treatment is not particularly limited, but is preferably 1000 to 5000 rpm, more preferably 1200 to 3800 rpm. Thereby, the fine dispersion of the finely divided pigment can be efficiently performed without lowering the productivity of the pigment dispersion. Further, it is possible to reliably prevent deterioration, modification, and the like due to heat or the like of the dispersion resin or the like.

After the first treatment, the second treatment using the second inorganic beads is performed. Thereby, a pigment dispersion in which the fine pigment particles are sufficiently finely dispersed can be obtained. It is preferred to remove the first inorganic beads before the second treatment. Thereby, the efficiency of fine dispersion of the pigment in the second treatment can be made particularly excellent. The removal of the first inorganic beads can be easily and reliably carried out, for example, by filtration or the like.

The second inorganic bead used in the second treatment is preferably one having a smaller particle diameter than the first inorganic bead used in the first treatment. In this way, the fine pigment can be finely dispersed in the pigment dispersion obtained at the end to be sufficiently finely dispersed, and the dispersion stability (long-term dispersion stability) of the fine pigment particles in the pigment dispersion can be made long. Excellent.

The average particle diameter of the second inorganic beads is not particularly limited, but is usually 0.03 to 0.3 mm, preferably 0.05 to 2.0 mm. When the average particle diameter of the second inorganic beads is within the above range, the efficiency of fine dispersion of the pigment in the entire microdispersion step can be made particularly excellent. On the other hand, when the average particle diameter of the second inorganic beads is less than the above-described lower limit, the efficiency of microdispersion of the second-treated fine pigment particles tends to decrease depending on the type of the pigment or the like. In addition, when the average particle diameter of the second inorganic beads exceeds the above upper limit, it may be difficult to sufficiently reduce the fine dispersion of the fine pigment particles.

The amount of the second inorganic beads to be used is not particularly limited, but is preferably 100 to 600 parts by weight, more preferably 200 to 500 parts by weight, per 100 parts by weight of the dispersion liquid dispersion.

The second treatment can be carried out using various mixers. Examples of the agitator that can be used in the second treatment include a MEDIA TYPE disperser such as a pear mill, or a shaft or biaxial mixer such as Dispermill.

The stirring treatment time (the treatment time of the second treatment) using the agitator is not particularly limited, but it is preferably 10 to 120 minutes, and more preferably 15 to 40 minutes. Thereby, the fine dispersion of the pigment can be sufficiently performed without lowering the productivity of the pigment dispersion.

Further, the number of rotations of the stirring blade included in the second processing mixer is not particularly limited, but is preferably 1000 to 5000 rpm, more preferably 1200 to 3800 rpm. Thereby, the fine dispersion of the pigment can be efficiently performed without lowering the productivity of the pigment dispersion. Further, it is possible to reliably prevent deterioration, modification, and the like due to heat or the like of the dispersion resin or the like.

The above description mainly describes the case where the microdispersion treatment is performed in two stages, but the three stages or more may be performed. At this time, the inorganic beads used for the post-treatment are preferably smaller than the small particle diameter of the inorganic beads used for the first treatment. By conforming to such a relationship, the efficiency of fine dispersion of the pigment particles can be made particularly excellent, and at the same time, the finely dispersed state of the finely divided pigment particles in the finally obtained pigment dispersion can be more effectively maintained.

[Examples]

The present invention will be more specifically described below by way of examples and comparative examples. However, the invention is not limited thereto. In addition, the "parts" indicated in the respective embodiments mean "parts by weight", and "%" means "% by weight". The outlines of the compositions of the pigment dispersions of the respective examples and comparative examples described below are shown in Table 1. Further, in the column of the dispersing agent of Table 1, "amphoteric type" means an amphoteric dispersing agent, "acid type" means an acid value dispersing agent, and "alkaline type" means an amine price dispersing agent. By "blending" is meant a mixture of an acid valence dispersant and an amine valence dispersant.

[Example 1] (Preparation of fine pigments)

Red pigment (CIPigment Red 254 (Irgaphor Red BT-CF (made by Ciba Japan)) 300 g, Glauber's salt (anhydrous sodium sulfate) (Mitsan Chemical Industry Co., Ltd. raw material Glauber's salt (average particle size 20 μm) became micro In the case where the content of particles having an average particle diameter of 3.6 μm and a particle diameter of 10 μm or more is 0.4%, hereinafter referred to as finely pulverized product, 3000 g, and diethylene glycol (DEG) (manufactured by Nippon Shokubai Co., Ltd.) 850 g, which was placed in a double-wrist type kneading machine (manufactured by MORIYAMA, 5 L), and kneaded at 50 ° C for 9 hours. The kneaded product was poured into 8 L of warm water (70 ° C), and stirred for 30 minutes to form a slurry.

Then, after filtering with a Buchner funnel, deionized water was added and the washing was performed until the conductivity of the washing liquid became 3 μS/cm or less. The washed product was dried in a dryer at 90 ° C for 16 hours, and pulverized by a pulverizer (manufactured by Kyoritsu Seiko Co., Ltd., SampleMill SK-M2) to obtain 300 g of a fine pigment. The obtained fine pigment had an average particle diameter of 25 nm.

(modulation of pigment dispersion)

An amphoteric dispersant (HINOACT T-8000E, manufactured by Kawasaki Fine Chemicals Co., Ltd., acid value: 3.8 mgKOH/g, amine price: 25.3 mgKOH/g), 65.15 g (161 parts), dispersion resin (RIPOXY SPC2000, Showa Polymer) (manufactured by the company) 14.32g (35 parts), solvent (Akesop PMA, manufactured by Chemical Co., Ltd.) 67.98g (168 parts) was put into a mixer with a content of 500mL, and stirred with a disperser for 10 minutes. Prepare for dispersion. Then, 34.37 g of the above-mentioned fine pigment (CIPigment Red 254), 2.43 g of Pigment Red 255 FGG (trade name, manufactured by Sanyo Pigment Co., Ltd.), and Pigment Red PT255S (trade name, Shanyang pigment) were added to the obtained preliminary dispersion. (4) g of the prepared pigment 40.44 g (100 parts), and further stirred for 10 minutes to obtain a pigment dispersion.

Into the pigment dispersion obtained, 720 g of an inorganic bead (manufactured by zirconia, "Toray ceram crushing ball" (trade name), manufactured by Toray Industries, Inc.) of 720 g of an average particle diameter of 0.8 mm was added, and the mixture was stirred at room temperature. After stirring in the first step, the dispersion dispersion of the pigment dispersion and the inorganic dispersion beads was filtered with a filter ("PALL HDCII Membrene Filter", manufactured by PALL Co., Ltd.) to remove the inorganic beads. Next, 720 g of inorganic beads (manufactured by zirconia, "Toray ceram crushing ball" (trade name), manufactured by Toray Industries, Inc.) of 720 g of an average particle diameter of 0.1 mm was added to the obtained pigment dispersion, and the mixture was further stirred for 120 minutes. The second phase of the decentralized operation.

The obtained mixed dispersion was filtered through a 2.5 μm mesh filter ("PALL HDCII Membrene Filter", manufactured by PALL Co., Ltd.) to separate inorganic beads, thereby preparing a pigment dispersion.

[Example 2]

In addition to using an acid valence dispersant (Disperbyk 111 (trade name), BYK-Chemie Japan Co., Ltd., acid price 129 mg KOH/g) 50 g and an amine valence dispersant (Disperbyk 162 (trade name), BYK-Chemie Japan (share) A pigment dispersion was prepared in the same manner as in Example 1 except that a mixture of an amine price of 13 mgKOH/g and 15 g was used instead of the amphoteric dispersant.

[Example 3]

In the preparation of the fine pigment, a red pigment (CIPigment Red 254 (Irgaphor Red BT-CF (manufactured by Ciba Japan)), Glauber's salt (finely pulverized product), and DEG were used at 50 ° C by a double-wrist type kneading machine. After 9 hours of kneading (the same prescription as in Example 1), 112.5 g of a polymer compound (manufactured by Showa Polymer Co., Ltd., RIPOXY SPC2000, 40% pure) of a surface treatment agent was added, and kneaded for 90 minutes to obtain a fine pigment. The pigment dispersion was prepared in the same manner as in Example 1 except that the surface treatment was carried out. Further, the average particle diameter of the obtained fine pigment was 30 nm. Further, the average particle diameter by surface treatment was slightly larger than that. The tendency of the surface treatment person is considered to be because the polymer compound of the surface treatment agent is adsorbed on the surface of the fine pigment particles.

[Comparative Example 1]

In the same manner as in Example 1, except that the red pigment (CIPigment Red 254 (Irgaphor Red BT-CF (manufactured by Ciba Japan Co., Ltd.)) was refined with Glauber's salt having an average particle diameter of 20 μm and the average particle diameter was 60 nm. Modulate the pigment dispersion.

[Comparative Example 2]

A pigment dispersion was prepared in the same manner as in Example 1 except that the acid value dispersant of Example 2 was used instead of the amphoteric dispersant.

[Comparative Example 3]

A pigment dispersion was prepared in the same manner as in Example 1 except that the amine-based dispersant of Example 2 was used instead of the amphoteric dispersant.

[Example 4] (Preparation of fine pigments)

Red pigment (CIPigment Red 177 (manufactured by Ciba Japan Co., Ltd., trade name "CROMOPHTAL RED A2B")), Glauber's salt (finely pulverized product) 3000 g, and diethylene glycol (DEG) (manufactured by Nippon Shokubai Co., Ltd.) 850 g was placed in a double-wrist type kneading machine (manufactured by MORIYAMA, 5 L), and kneaded at 50 ° C for 9 hours. This kneaded material was poured into 8 L of warm water (70 ° C), and stirred for 30 minutes to form a slurry.

Then, after filtering with a Buchner funnel, deionized water was added and the washing was performed until the conductivity of the washing liquid became 3 μS/cm or less. The washed product was dried in a dryer at 90 ° C for 16 hours, and pulverized by a pulverizer (manufactured by Kyoritsu Seiko Co., Ltd., SampleMill SK-M2) to obtain 300 g of a fine pigment. The obtained fine pigment had an average particle diameter of 25 nm.

(modulation of pigment dispersion)

An amphoteric dispersant (HINOACT T-8000E (trade name), manufactured by Kawasaki Fine Chemicals Co., Ltd., acid value: 3.8 mgKOH/g, amine price: 25.3 mgKOH/g), 65.15 g (161 parts), dispersion resin (RIPOXY SPC2000, 14.32g (35 parts), solvent (Akesop PMA, Concord fermentation CHEMICAL) 67.98g (168 parts) was put into a mixer with a content of 500mL, and stirred with a disperser. Prepare for dispersion in 10 minutes. Then, 40.44 g (100 parts) of a pigment obtained by adding 63.37 g of the fine pigment (Pigment Red PT177S (trade name, manufactured by Shanyang Pigment Co., Ltd., pigment derivative)) to the obtained preliminary dispersion was added. Stirring was further carried out for 10 minutes to obtain a pigment dispersion.

Into the pigment dispersion obtained, 720 g of an inorganic bead (manufactured by zirconia, "Toray ceram crushing ball" (trade name), manufactured by Toray Industries, Inc.) of 720 g of an average particle diameter of 0.8 mm was added, and the mixture was stirred at room temperature. After the first stage of the dispersion treatment, the mixed dispersion of the pigment dispersion and the inorganic dispersion beads was filtered with a filter ("PALL HDCII Membrene Filter", manufactured by PALL Co., Ltd.) to remove inorganic beads. Next, 720 g of inorganic beads (manufactured by zirconia, "Toray ceram crushing ball" (trade name), manufactured by Toray Industries, Inc.) of 720 g of an average particle diameter of 0.1 mm was added to the obtained pigment dispersion, and the mixture was further stirred for 120 minutes. The second phase of the decentralized operation.

The obtained mixed dispersion was filtered through a 2.5 μm mesh filter ("PALL HDCII Membrene Filter", manufactured by PALL Co., Ltd.) to separate inorganic beads, thereby preparing a pigment dispersion.

[Example 5]

A pigment dispersion was prepared in the same manner as in Example 4 except that the mixture of the acid value dispersant of Example 2 and the amine valence dispersant was used instead of the amphoteric dispersant.

[Example 6]

In the preparation of the fine pigment, a red pigment (CIPigment Red 177 (manufactured by Ciba Japan Co., Ltd., trade name "CROMOPHTAL RED A2B")), Glauber's salt (finely pulverized product), and DEG are used in a double-wound type kneading machine. After kneading at 50 ° C for 9 hours (the same prescription as in Example 4), 112.5 g of a polymer compound (made by Showa Polymer Co., Ltd., RIPOXY SPC2000, pure fraction 40%) of a surface treatment agent was added, and kneaded for 90 minutes to make fine A pigment dispersion was prepared in the same manner as in Example 4 except that the pigment was subjected to surface treatment. Further, the obtained fine pigment had an average particle diameter of 30 nm.

[Comparative Example 4]

In addition to the use of a red pigment (CIPigment Red 177 (manufactured by Ciba Japan Co., Ltd., trade name "CROMOPHTAL RED A2B")) with a Glauber's salt having an average particle diameter of 20 μm, the average particle diameter is 60 nm, and Example 4 is used. The pigment dispersion was prepared in the same manner.

[Comparative Example 5]

A pigment dispersion was prepared in the same manner as in Example 4 except that the acid value dispersant of Example 2 was used instead of the amphoteric dispersant.

[Comparative Example 6]

A pigment dispersion was prepared in the same manner as in Example 4 except that only the amine valence dispersant of Example 2 was used instead of the amphoteric dispersant.

[Example 7] (Adjustment of fine pigments)

Blue pigment (CIPigment Blue 15:6 (made by Toyo Ink Co., Ltd., trade name "Lionol Blue E")) 300 g, Glauber's salt (finely pulverized product) 3000 g, and diethylene glycol (DEG) ((share) 850 g of Nippon Shokubai Co., Ltd. was placed in a double wrist type kneading machine (manufactured by MORIYAMA, 5 L), and kneaded at 50 ° C for 9 hours. This kneaded material was poured into 8 L of warm water (70 ° C), and stirred for 30 minutes to form a slurry.

Then, after filtering with a Buchner funnel, deionized water was added and the washing was performed until the conductivity of the washing liquid became 3 μS/cm or less. The washed product was dried in a dryer at 90 ° C for 16 hours, and pulverized by a pulverizer (manufactured by Kyoritsu Seiko Co., Ltd., SampleMill SK-M2) to obtain 300 g of a fine pigment. The obtained fine pigment had an average particle diameter of 25 nm.

(modulation of pigment dispersion)

An amphoteric dispersant (HINOACT T-8000E (trade name), manufactured by Kawasaki Fine Chemicals Co., Ltd., acid value: 3.8 mgKOH/g, amine price: 25.3 mgKOH/g), 65.15 g (161 parts), dispersion resin (RIPOXY SPC2000, 14.32g (35 parts), solvent (Akesop PMA (trade name), Kyowa fermentation CHEMICAL), 67.98g (168 parts) was put into a mixer with a content of 500mL. The mixture was stirred for 10 minutes with a disperser to carry out preliminary dispersion. Next, a pigment obtained by adding 36.8 g of the above-mentioned fine pigment (CIPigment Blue 15:6) and 3.2 g of a pigment derivative (SOLSPERSE 12000 (trade name), Avecia) was added to the obtained preliminary dispersion. 40.00 g (100 parts) was further stirred for 10 minutes to obtain a pigment dispersion.

Into the pigment dispersion obtained, 720 g of an inorganic bead (manufactured by zirconia, "Toray ceram crushing ball" (trade name), manufactured by Toray Industries, Inc.) of 720 g of an average particle diameter of 0.8 mm was added, and the mixture was stirred at room temperature. After the first stage of the dispersion treatment, the mixed dispersion of the pigment dispersion and the inorganic dispersion beads was filtered with a filter ("PALL HDCII Membrene Filter", manufactured by PALL Co., Ltd.) to remove inorganic beads. Next, 720 g of inorganic beads (manufactured by zirconia, "Toray ceram crushing ball" (trade name), manufactured by Toray Industries, Inc.) of 720 g of an average particle diameter of 0.1 mm was added to the obtained pigment dispersion, and the mixture was further stirred for 120 minutes. The second phase of the decentralized operation.

The obtained mixed dispersion was filtered through a 2.5 μm mesh filter ("PALL HDCII Membrene Filter", manufactured by PALL Co., Ltd.) to separate inorganic beads, thereby preparing a pigment dispersion.

[Example 8]

A pigment dispersion was prepared in the same manner as in Example 7 except that the mixture of the acid value dispersant of Example 2 and the amine valence dispersant was used instead of the amphoteric dispersant.

[Comparative Example 7]

In addition to the use of a blue pigment (CIPigment Blue 15:6 (manufactured by Toyo Ink Co., Ltd., trade name "Lionol Blue E")), the average particle diameter is 60 nm, and the average particle diameter is 60 nm. The pigment dispersion was prepared in the same manner as in Example 7.

[Comparative Example 8]

A pigment dispersion was prepared in the same manner as in Example 7 except that the acid value dispersant of Example 2 was used instead of the amphoteric dispersant.

[Comparative Example 9]

A pigment dispersion was prepared in the same manner as in Example 7 except that the amine-based dispersant of Example 2 was used instead of the amphoteric dispersant.

[Example 9] (Preparation of fine pigments 1)

300 g of green pigment (CIPigment Green 36 (Lionol Green 6YK manufactured by Toyo Ink Co., Ltd.)), 3000 g of Glauber's salt (finely pulverized product), and 850 g of diethylene glycol (DEG) (manufactured by Nippon Shokubai) In a double wrist type kneading machine (manufactured by MORIYAMA, 5 L), the mixture was kneaded at 50 ° C for 9 hours. This kneaded material was poured into 8 L of warm water (70 ° C), and stirred for 30 minutes to form a slurry.

Then, after filtering with a Buchner funnel, deionized water was added and the washing was performed until the conductivity of the washing liquid became 3 μS/cm or less. The washed product was dried in a dryer at 90 ° C for 16 hours, and pulverized by a pulverizer (manufactured by Kyoritsu Seiko Co., Ltd., SampleMill SK-M2) to obtain 300 g of a fine pigment. The obtained fine pigment had an average particle diameter of 30 nm.

(Preparation of fine pigments 2)

A yellow pigment (C.I. Pigment Yellow 150 (Yellow Pigemnt E4GN, manufactured by LANXESS)) was subjected to a refining treatment under the same conditions as above to obtain 300 g of a fine pigment. The obtained fine pigment had an average particle diameter of 40 nm.

(modulation of pigment dispersion)

An amphoteric dispersant (HINOACT T-8000E (trade name), manufactured by Kawasaki Fine Chemicals Co., Ltd., acid value: 3.8 mgKOH/g, amine price: 25.3 mgKOH/g), 65.15 g (161 parts), dispersion resin (RIPOXY SPC2000, 14.32g (35 parts), solvent (Akesop PMA, Concord fermentation CHEMICAL) 67.98g (168 parts) was put into a mixer with a content of 500mL, and stirred with a disperser. Prepare for dispersion in 10 minutes. Next, 24.06 g of the fine green pigment (Pigment Green 36), 10.31 g of the fine yellow pigment (Pigment Yellow 150), and a pigment derivative (Pigment Yellow 138S) were added to the obtained preliminary dispersion. 40.44 g (100 parts) of the pigment formed by 6.07 g of the product, and the product was further stirred for 10 minutes to obtain a pigment dispersion.

Into the pigment dispersion obtained, 720 g of an inorganic bead (manufactured by zirconia, "Toray ceram crushing ball" (trade name), manufactured by Toray Industries, Inc.) of 720 g of an average particle diameter of 0.8 mm was added, and the mixture was stirred at room temperature. After the first stage of the dispersion treatment, the mixed dispersion of the pigment dispersion and the inorganic dispersion beads was filtered with a filter ("PALL HDCII Membrene Filter", manufactured by PALL Co., Ltd.) to remove inorganic beads. Next, 720 g of inorganic beads (manufactured by zirconia, "Toray ceram crushing ball" (trade name), manufactured by Toray Industries, Inc.) of 720 g of an average particle diameter of 0.1 mm was added to the obtained pigment dispersion, and the mixture was further stirred for 120 minutes. The second phase of the decentralized operation.

The obtained mixed dispersion was filtered through a 2.5 μm mesh filter ("PALL HDCII Membrene Filter", manufactured by PALL Co., Ltd.) to separate inorganic beads, thereby preparing a pigment dispersion.

[Example 10]

A pigment dispersion was prepared in the same manner as in Example 9 except that the mixture of the acid value dispersant of Example 2 and the amine valence dispersant was used instead of the amphoteric dispersant.

[Example 11]

In the preparation 2 of the fine pigment of Example 9, except for the yellow pigment (CIPigment Yellow 150 (Yellow Pigemnt E4GN, LANXESS)), Glauber's salt (finely pulverized product), and DEG by a double-wrist type kneading machine, After kneading at 50 ° C for 9 hours (the same prescription as in Example 9), 112.5 g of a polymer compound (made by Showa Polymer Co., Ltd., RIPOXY SPC2000, pure fraction 40%) of a surface treatment agent was added, and kneading was carried out for 90 minutes. A pigment dispersion was prepared in the same manner as in Example 9 except that the fine pigment was subjected to surface treatment. Further, the obtained fine pigment had an average particle diameter of 50 nm.

[Comparative Example 10]

In addition to using a green pigment (CIPigment Green 36 (Lionol Green 6YK manufactured by Toyo Ink Co., Ltd.)) and a yellow pigment (CIPigment Yellow 150 (Yellow Pigemnt E4GN, manufactured by LANXESS)), Glauber's salt having an average particle diameter of 20 μm is used. A pigment dispersion was prepared in the same manner as in Example 9 except that the average particle diameter was 50 nm and 60 nm.

[Comparative Example 11]

A pigment dispersion was prepared in the same manner as in Example 9 except that the acid value dispersant of Example 2 was used instead of the amphoteric dispersant.

[Comparative Example 12]

A pigment dispersion was prepared in the same manner as in Example 9 except that the amine-based dispersant of Example 2 was used instead of the amphoteric dispersant.

〔Evaluation〕

With respect to the pigment dispersion prepared in the above examples and comparative examples, the viscosity stability of the pigment dispersion was evaluated, and a color filter was prepared by using the above pigment dispersion, and the contrast was measured to evaluate the pigment dispersion of the present invention. Dispersion stability of the body and its performance as a color filter.

(Viscosity stability of pigment dispersion)

Viscosity stability, after being placed in an environment of 40 ° C for 7 days (after the preparation of the pigment dispersion) and after being placed, the viscosity (dynamic viscosity) of each pigment dispersion prepared in the examples and the comparative examples was measured, and the temperature was measured. The condition is 25 °C.

The measurement of the viscosity (dynamic viscosity) of the pigment dispersion was carried out in accordance with JIS Z8809 using an E-type viscometer (RE-01 manufactured by Toki Sangyo Co., Ltd.). The results are shown in Table 1. The unit of "initial viscosity" in the table is mPa. s. Further, the above-described rate of change is a value calculated from (measured value of viscosity after leaving for 7 days at 40 ° C) / (measured value of viscosity before standing).

(performance of color filters) <Modulation of Color Filter>

The viscosity of each of the pigment dispersions was measured by an E-type viscometer (manufactured by Toki Sangyo Co., Ltd., TV-22 type viscometer), and the solid content of each of the pigment dispersions was confirmed at 130 ° C for 1 hour. Using this pigment dispersion, a spin coating liquid (hereinafter referred to as SPC liquid) was prepared, and the solid content of the solid content in the dispersion and the binder used in the SPC liquid was adjusted to 1:1. The SPC liquid was applied to a glass plate having a thickness of 1 mm and 100 mm square by using a spin coater (manufactured by MIKASA Co., Ltd., spin coater MS-150A) in three stages, and was applied to the air path (air path). It was dried at 90 ° C for 2.5 minutes (prebaking step). As described above, a color filter is obtained.

<Comparative measurement>

Next, the color of the three glass coating plates after the prebaking step was confirmed (the number of rotations at the time of spin coating was set according to Yxy chromaticity). The chromaticity was measured by a spectrophotometer (Konica Minolta Sensing Co., Ltd., spectrophotometer, CM-3700d) depending on the viscosity of the dispersion and the number of rotations of the spin coating. Plot the measured values to confirm that the linearity is maintained.

Next, the brightness of the glass coated board was measured with a color luminance meter (manufactured by Konica Minolta Sensing Co., Ltd., brightness meter LS-100). A polarizing plate (TOLAX-38S, manufactured by Luceo Co., Ltd.) was placed on the backlight so that the distance between the polarizing plate and the glass coated plate was set to 1 mm. A rotatable polarizing plate is disposed on the upper portion thereof, and after confirming that the brightness of the backlight is very stable, the brightness of the glass coating plate is measured. The polarizing plate was adjusted to the position of crossed Nicols, and the brightness was measured, followed by rotation at 90°, and the brightness was measured at parallel positions. At the position of a certain chromaticity, the Yxy chromaticity and each brightness are analyzed using the analysis software, and the results are shown in Table 1. Furthermore, the values of "initial comparison" in Table 1 are values that will be placed 7 days before in an environment of 40 °C.

From Table 1, it can be seen that even if any of the pigments are used, the pigment dispersion of the examples has a high content (high concentration) and a dynamic viscosity of 12 mPa. Below m, the viscosity increase rate is 1.1 or less, and the contrast of the color filter prepared by the color filter is excellent as compared with the comparative example. In particular, a pigment dispersion using a surface-treated fine pigment has an extremely high contrast of a color filter, and is extremely excellent as a pigment dispersion for a color filter.

Claims (3)

A pigment dispersion for a color filter, which comprises a pigment dispersion of a fine pigment, a dispersant, a dispersion resin, and a solvent, characterized in that the fine pigment is finely refined by a salt milling treatment and further a surface When the treating agent is treated, the dispersing agent contains at least one compound having an acid value of 2 mgKOH/g or more and an amine value of 0 mgKOH/g and a compound having an amine value of 10 mgKOH/g or more and an acid value of 0 mgKOH/g. The mixture, or a compound having an amine value of 10 mgKOH/g or more and an acid value of 2 mgKOH/g or more. The pigment dispersion for a color filter according to the first aspect of the invention, wherein the finely divided pigment has an average particle diameter of 10 to 50 nm. The pigment dispersion for a color filter according to the first aspect of the invention, wherein the solvent is a high boiling point solvent having a boiling point of 180 ° C or higher.