JPH09208848A - Production of fused polycyclic red pigment and optical element prepared by using this pigment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a fused polycyclic red pigment which is fine, has a uniform particle size distribution, and is improved in clearness and transparency by continuously adding a sulfuric acid solution of a fused polycyclic red pigment to running water. SOLUTION: One (1) pt.wt. fused polycyclic red pigment comprising an anthraquinone red pigment or perylene red pigment is dissolved in 3-50 pts.wt. sulfuric acid having a concentration of 70-100wt.% to obtain a sulfuric acid solution. One (1) pt.wt. this solution is continuously added dropwise to 3-50 pts.wt. running water at 5-25 deg.C to precipitate the fused polycyclic red pigment.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a condensed polycyclic red pigment and an optical element using the condensed polycyclic red pigment obtained by the production method. A method for producing a condensed polycyclic red pigment with a uniform distribution, and a color filter for a liquid crystal display device, which is obtained by using the condensed polycyclic red pigment obtained by the production method, to form clear and high-contrast red pixels. The present invention relates to an optical element which can be particularly preferably used.

[0002]

2. Description of the Related Art Red organic pigments include azo red pigments such as azo lake pigments and insoluble azo pigments, quinacridone pigments, perylene pigments, perinone pigments, anthraquinone pigments, thioindigo pigments, and diketopyrrolopyrroles. Condensed polycyclic red pigments such as pigments have been known, and condensed polycyclic red pigments have been favored especially for applications requiring high heat resistance, light resistance, weather resistance and the like.

It is not suitable to use these condensed polycyclic red pigments as pigments as they are chemically synthesized, and they are usually given aptitude as a pigment through a step called pigmentation. There is.

The condensed polycyclic red pigment is pigmented by a method of applying mechanical shearing force, a method of treating with an organic solvent, a method of utilizing an oxidation / reduction reaction, a method of dissolving in sulfuric acid or phosphoric acid, and the like in water. In addition to the above, a method of diluting / precipitating (acid paste method) and the like are known. Particularly, the acid paste method is widely used because the operation is simple.

On the other hand, in computers, televisions and the like, liquid crystal display elements have been widely used for the purpose of making displays thinner and saving power. The liquid crystal display element
Color can be obtained by combining with a color filter. Conventionally, dyes have been mainly used as colorants for color filters. However, the shift to pigments is progressing against the backdrop of increasing demands for quality such as light resistance.

The pigment used in the color filter includes
In addition to being clear and transparent, it is also required to have excellent heat resistance due to the requirements in the color filter manufacturing process.

Due to such quality requirements, condensed polycyclic red pigments centering on anthraquinone pigments are used as red pigments for color filters.

[0008]

However, in order to produce fine condensed polycyclic red pigments suitable for color filter applications by the acid paste method, for example, Japanese Patent Application Laid-Open No. HEI 5 (1999) -53138 has been proposed.
As described in JP-A-39435, it was necessary to add a sulfuric acid solution of a condensed polycyclic red pigment in ice in order to inject at a temperature of an aqueous suspension not exceeding 0 ° C.
This method requires ice-making equipment, which not only causes the manufacturing equipment to be expensive, but also makes the manufacturing operation complicated. Moreover, when the obtained pigment is used for a color filter, its sharpness and transparency are not always satisfactory.

The problem to be solved by the present invention is a condensed polycyclic pigment which does not require expensive manufacturing equipment, does not require complicated manufacturing operations, and is excellent in heat resistance, and is suitable for optical elements such as color filters. An object of the present invention is to provide a condensed polycyclic pigment having excellent sharpness and transparency when used.

[0010]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted extensive research on a method for pigmenting condensed polycyclic red pigments, particularly for producing condensed polycyclic red pigments suitable for use in color filters. As a result, the sulfuric acid solution of the condensed polycyclic red organic pigment was continuously added to running water to precipitate the condensed polycyclic red organic pigment, and the condensed polycyclic red pigment was used for the color filter. In this case, they found that they exhibited excellent suitability, and completed the present invention.

That is, in order to solve the above-mentioned problems, the present invention is characterized by comprising a step of continuously adding a sulfuric acid solution of a condensed polycyclic red organic pigment to running water to precipitate the condensed polycyclic red pigment. A method for producing a condensed polycyclic red pigment is provided.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION As the condensed polycyclic red organic pigment used in the present invention, any one may be used as long as it is soluble in sulfuric acid and does not cause remarkable decomposition in a sulfuric acid solution. it can.

Examples of such condensed polycyclic red organic pigments include C.I. I. Pigment Red 122, C.I.
I. Pigment Red 202, C.I. I. Pigment Red 207, C.I. I. Pigment Red 20
9, C.I. I. Pigment Violet 19; a quinacridone pigment such as C.I. I. Pigment Red 123,
C. I. Pigment Red 149, C.I. I. Pigment Red 179, C.I. I. Pigment Red 1
89, C.I. I. Pigment Red 190, a perylene pigment such as C.I. I. Pigment Red 194, a perinone-based pigment such as C.I. I. Pigment Red 16
8, C.I. I. Pigment Red 177, C.I. I. Pigment Red 216; anthraquinone pigments such as C.I. I. Pigment Red 86, C.I. I. Pigment Red 88, C.I. I. Pigment Red
Thioindigo pigments such as C.198; I. Pigment Red 254 and other diketopyrrolopyrrole pigments. Of these, perylene pigments and anthraquinone pigments are preferable in consideration of hue, sharpness, transparency and the like required for optical elements, and in particular, C.I.
I. Pigment Red 177 and C.I. I. Pigment Red 179 is particularly preferable.

The concentration of sulfuric acid used for dissolving these condensed polycyclic red pigments is particularly limited as long as the condensed polycyclic red pigment is dissolved and is not subjected to a chemical reaction such as sulfonation or oxidation. Not normally, but usually 70-100% by weight
It is economically and operably advantageous if a commercially available concentrated sulfuric acid of 95 to 98% by weight can be used.

The ratio of the condensed polycyclic red pigment to sulfuric acid depends on the solubility of the condensed polycyclic red pigment in sulfuric acid, but is not particularly limited as long as the condensed polycyclic red pigment is completely dissolved. However, considering the stabilization of the quality and the economical efficiency, the range of 3 to 50 parts by weight of sulfuric acid is preferable, and the range of 5 to 20 parts by weight is particularly preferable, relative to 1 part by weight of the condensed polycyclic red pigment. When the amount of sulfuric acid used for 1 part by weight of the condensed polycyclic red pigment is less than 1 part by weight, it takes time to completely dissolve the condensed polycyclic red pigment, which not only lowers the productivity but also It is not preferable because the condensed polycyclic red pigment may be deposited at a microscopic level due to moisture absorption during the manufacturing operation, which may deteriorate the quality of the product. On the other hand, when the amount of sulfuric acid used for 1 part by weight of the condensed polycyclic red pigment is more than 50 parts by weight, it is economically disadvantageous, and the amount of waste water increases, which causes a disadvantage in terms of environmental load. Because there is a tendency
Not preferred.

The ratio of the flow rate of the condensed polycyclic red pigment sulfuric acid solution and the dilution water is preferably in the range of 3 to 50 parts by weight of the dilution water with respect to 1 part by weight of the condensed polycyclic red pigment sulfuric acid solution. Particularly, the flow rate of the diluting water is preferably in the range of 7 to 25 parts by weight per 1 part by weight of the condensed polycyclic red pigment sulfuric acid solution.

When the flow rate of the diluting water is less than 3 parts by weight per 1 part by weight of the condensed polycyclic red pigment sulfuric acid solution,
This is not preferable because not only the temperature rise due to the heat of dilution is significant and it is dangerous in the manufacturing operation, but also the primary particles of the pigment may grow due to heat and the quality may deteriorate. When the flow rate of the condensed polycyclic red pigment sulfuric acid solution is more than 50 parts by weight with respect to 1 part by weight, the capacity of the reaction equipment becomes too large, which is economically disadvantageous, and there is a problem that the amount of waste water increases. It is not preferable because it tends to occur.

Although the room temperature is most economically advantageous as the water temperature of the dilution water, it suppresses the quality change due to the seasonal fluctuation of the water temperature,
In order to maintain high quality, it is preferable to have a controlled constant temperature within the range of 5 to 25 ° C. If the dilution water temperature is higher than 25 ° C, there is a risk of primary pigment particles growing due to the temperature rise due to the heat of dilution, which is not preferable. If the dilution water temperature is lower than 5 ° C, the dilution water should be adjusted. It requires a long cooling time and cooling energy, which is not preferable.

The condensed polycyclic red pigment obtained by the production method of the present invention is used as a wet cake or as a dry pigment after dry pulverization, as a printing ink, a paint, a plastic, a metal ink, a printing agent, a stationery, a toner, a jet ink. It can be used as a colorant for various articles, but it can be particularly suitably used for an optical element such as a color filter by utilizing its vividness and transparency.

When used as a colorant, the obtained pigment may be used as it is, or may be used after being treated with a surfactant, a resin, a rosin, a pigment derivative or the like.

To prepare an optical element using the condensed polycyclic red pigment of the present invention, at least the condensed polycyclic red pigment of the present invention is contained on a transparent substrate such as a glass plate or a transparent resin film. A thin film may be formed. Examples of thin film forming methods include spin coating, printing, electrolysis, and
Wet process using pigment dispersion such as electrodeposition method, vapor deposition,
Dry processes such as sputtering may be mentioned, but in order to utilize the characteristics of the condensed polycyclic red pigment produced by the production method of the present invention, a pigment dispersion containing the condensed polycyclic red pigment of the present invention was used. Wet processes are preferred.

A resin having film-forming properties may be added to the pigment dispersion containing the condensed polycyclic red pigment of the present invention, or a surfactant, a dispersant, an antifoaming agent, a leveling agent, etc. may be added. Agents can also be added.

Examples of the film-forming resin include polyester resin, polycarbonate resin, polyvinyl butyral resin, polyvinyl carbazole resin, polystyrene resin, polyvinyl acetate resin, polyvinyl chloride resin,
Polyvinylidene chloride resin, polyvinylidene fluoride resin,
Acrylic resin, methacrylic resin, silicone resin, alkyd resin, melamine resin, melamine-alkyd resin, phenolic resin, polyamide resin, polyurethane resin, polyimide resin, epoxy resin, phenoxy resin,
Styrene-butadiene copolymer, styrene-maleic anhydride copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, and the like. In addition, a resin precursor that can generate these resins by the action of heat, light, an electron beam, or the like can also be used.

Examples of the solvent which can be used for preparing the pigment dispersion include hydrocarbons such as toluene, xylene and mineral spirit; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; dichloromethane, dichloroethane, trichloroethane and trichloroethylene. , Halogenated hydrocarbons such as chlorobenzene; ethers such as tetrohydrofuran, dioxane, monoglyme, diglyme and anisole; methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, cyclohexanol, 2-methoxy-1. Alcohols such as propanol, 2-butoxy-1-propanol; ethyl acetate, propyl acetate, butyl acetate, cellosolve acetate Butyl cellosolve acetate, acetic acid 2-methoxy-1-propyl acetate, 2-butoxy -1
-Esters such as propyl; dimethylformamide,
Amides such as N-methylpyrrolidone; water and the like can be mentioned. These solvents can be used in combination of two or more.

To prepare the pigment dispersion, the condensed polycyclic red pigment of the present invention, a solvent, and, if necessary, a binder, additives and the like are ball milled, bead milled, sand milled,
It may be dispersed using a dispersing means such as a pearl mill, a paint shaker, a sand grinder, an attritor, a disperser, a homomixer, and an ultrasonic disperser.

[0026]

The present invention will be described below in more detail with reference to Examples and Comparative Examples. In the following examples, "part"
Means "parts by weight".

Example 1 To 800 parts of 97% by weight sulfuric acid, crude C.I. I. Pigment Red 177100
The parts were dissolved. 40% of the above sulfuric acid solution was put into an ejector in which dilution water of 15 ° C. was passed at a flow rate of 4000 parts / hour.
It was supplied at a flow rate of 0 part / hour to dilute and precipitate. After filtering the obtained pigment, the residue is washed with water until the washing liquid becomes neutral, and C.I. I. Pigment Red 177 wet cake was obtained. In addition, after vacuum drying a part at 50 ° C.,
Grinding gave a dry pigment.

<Example 2> The same procedure as in Example 1 was repeated except that the flow rate of the diluting water was changed to 8000 parts / hour. I. Pigment Red 177 pigment was obtained.

<Example 3> The same procedure as in Example 1 was repeated except that the flow rate of the diluting water was changed to 12000 parts / hour. I. Pigment Red 177 pigment was obtained.

<Example 4> In the same manner as in Example 1 except that the amount of 97% sulfuric acid used was changed from 800 parts to 1500 parts and the flow rate of dilution water was changed to 8000 parts / hour. C. I. Pigment Red 177 pigment was obtained.

<Embodiment 5> In the embodiment 1, the crude C.I. I. Pigment Red 177, instead of crude C.I. I. Pigment Red 179 (100 parts) was used, and C.I. I. Pigment Red 179 pigment was obtained.

<Embodiment 6> In Example 1, a crude C.I. I. Pigment Red 177, instead of crude C.I. I. Pigment Violet 19 (100 parts) was used, and C.I. I. Pigment Violet 19 pigment was obtained.

<Comparative Example 1> A crude C.I. I. Pigment Red 177 (100 parts) was dissolved. 9000 parts of diluted water at 15 ° C. was added to the crystallization tank, and the above sulfuric acid solution was injected while stirring to dilute and precipitate. After filtering the obtained pigment, the residue is washed with water until the washing liquid becomes neutral, and C.I. I. Pigment Red 17
A wet cake of 7 was obtained. Further, a part was vacuum dried at 50 ° C. and then pulverized to obtain a dry pigment.

<Comparative Example 2> In Comparative Example 1, the crude C.I. I. Pigment Red 177, instead of crude C.I. I. Pigment Red 179 in the same manner as in Comparative Example 1 except that 100 parts of C.I. I. Pigment
A red 179 wet cake and dry pigment were obtained.

<Example 7> (Preparation and evaluation of optical element) The C.V. obtained in Example 1 was placed in a glass container. I. Pigment
Red 177 dry pigment 2 parts, UV curable acrylic resin (“Unidick S5-122”: Dainippon Ink and Chemicals, Inc.) 4 parts, 2-butoxy-1-propanol 94 parts and average particle size 0.4 mm. 300 parts of the zirconia beads of was added and shaken for 2 hours using a paint shaker to prepare a coating solution.

The obtained coating solution was applied to a spin coater (1H-
3D type: glass plate (70)
59: manufactured by Corning Inc.) to obtain an optical element composed of a colored glass plate. The coating condition is 200r
pm for 10 seconds, then 2000 rpm for 30 seconds.

The transmission spectrum of the obtained optical element was measured by a spectrophotometer (U-3500 type: manufactured by Hitachi, Ltd.), and the transmittance at a wavelength of 650 nm was 81.2.
%, The transmittance at a wavelength of 450 nm was 0.5%.

Comparative Example 3 In Example 7, Example 1
C. obtained in I. Pigment Red 177 in place of the dry pigment, the C.I. I. Pigment Red 177, except that 2 parts of the dry pigment was used to obtain an optical element composed of a colored glass plate in the same manner as in Example 7.

The transmission spectrum of the obtained optical element was measured in the same manner as in Example 7. As a result, the transmittance at a wavelength of 650 nm was 75.4% and the transmittance at a wavelength of 450 nm was 1.
6%, which was inferior to the optical element obtained in Example 7 in color purity and transparency.

<Embodiment 8> In Embodiment 7, Embodiment 1
C. obtained in I. Pigment Red 177 in place of the dry pigment, the C.I. I. Pigment Red 179, except that 2 parts of a dry pigment was used, an optical element made of a colored glass plate was obtained in the same manner as in Example 7.

The transmission spectrum of the obtained optical element was measured in the same manner as in Example 7. As a result, the transmittance at a wavelength of 650 nm was 79.4% and the transmittance at a wavelength of 440 nm was 0.
4%.

<Comparative Example 4> In Example 7, Example 5
C. obtained in I. Pigment Red 179 in place of the dry pigment, the C.I. I. Pigment Red 179, except that 2 parts of a dry pigment was used, an optical element made of a colored glass plate was obtained in the same manner as in Example 7.

The transmission spectrum of the obtained optical element was measured in the same manner as in Example 7. As a result, the transmittance at a wavelength of 650 nm was 76.1% and the transmittance at a wavelength of 440 nm was 1.
3%, which was inferior to the optical element obtained in Example 8 in color purity and transparency.

<Example 9> The C.I. I. Pigment Red 177 wet pigment and an aqueous dispersion prepared from polyoxyethylene dodecyl ether (manufactured by Wako Pure Chemical Industries, Ltd.), Chemistry Letters magazine 19
According to the method described on page 1137 of 1989, C.I. I. Pigment Red
An optical element was formed by forming a thin film of 177.

The transmission spectrum of the obtained optical element was measured in the same manner as in Example 7. As a result, the transmittance at a wavelength of 650 nm was 80.1% and the transmittance at a wavelength of 450 nm was 0.
It was 6%.

Comparative Example 5 In Example 9, Example 1
C. obtained in I. Pigment Red 177 in place of the wet pigment, the C.I. I. Pigment Red 177 wet pigment was used in the same manner as in Example 9 to obtain an optical element.

The transmission spectrum of the obtained optical element was measured in the same manner as in Example 7. As a result, the transmittance at a wavelength of 650 nm was 73.5% and the transmittance at a wavelength of 450 nm was 1.
8%, which was inferior to the optical element obtained in Example 9 in color purity and transparency.

<Example 10> (Evaluation of suitability for color filter) The contrast ratio of the optical element obtained in Example 7 was measured using a backlight (manufactured by Meita System Co., Ltd .: brightness 6000 candela / m ² ) and a pair of polarizing plates. (NPF-G1229DUN:
Nitto Denko Corporation / OA-2 Alkali-free glass: Nippon Electric Glass Co., Ltd. and color luminance meter (BM-7 type:
It was 900 when measured using a contrast ratio measuring device made by Topcon Corporation.

Comparative Example 6 The contrast ratio was measured in the same manner as in Example 10 except that the optical element obtained in Comparative Example 3 was used in place of the optical element obtained in Example 7. , 750.

[0050]

The condensed polycyclic red pigment produced by the production method of the present invention has excellent sharpness and transparency and can be suitably used for optical elements, particularly color filters.

Claims (7)

[Claims] 1. A method for producing a condensed polycyclic red pigment, comprising the step of continuously adding a sulfuric acid solution of the condensed polycyclic red organic pigment to running water to precipitate the condensed polycyclic red pigment. . 2. The method for producing a condensed polycyclic red organic pigment according to claim 1, wherein the condensed polycyclic red pigment is an anthraquinone red pigment or a perylene red pigment. 3. A condensed polycyclic red pigment is C.I. I. Pigment Red 177 or C.I. I. Pigment Red 179. The process for producing a condensed polycyclic red organic pigment according to claim 1. 4. The flow rate ratio of the sulfuric acid solution of the condensed polycyclic red pigment and water is in the range of 3 to 50 with respect to the flow rate 1 of the condensed polycyclic red pigment sulfuric acid solution. Or the method for producing a condensed polycyclic red pigment according to the item 3. 5. The flow rate ratio of the sulfuric acid solution of the condensed polycyclic red pigment and water is such that the flow rate of water is in the range of 7 to 25 with respect to the flow rate of the sulfuric acid solution of the condensed polycyclic red pigment. Or the method for producing a condensed polycyclic red pigment according to the item 3. 6. An optical element comprising a condensed polycyclic red pigment obtained by the method according to claim 1, 2, 3 or 4 in a pixel. 7. A color filter comprising the optical element according to claim 6 as a constituent element.