JP2002265840A - Red color-resist ink and color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a red color-resist ink having excellent thermal crystal precipitation resistance when exposuring of a coating film to high temperatures and a high-quality color ink filter using the same. SOLUTION: In this red color resist ink obtained by dispersing a red pigment to a photosensitive resin composition, the red pigment is a diketopyrrolopyrrole pigment having 0.600-0.800 degree of half value width of intensity peak at 2θ of 28-29 degrees in an X-ray diffraction intensity measurement and the photosensitive resin composition comprises an acid hydroxide polycondensate as a photosensitive resin component obtained by reacting a (meth)acrylate represented by general formula 1 with a biphenyltetracarboxylic acid dianhydride to give the red color resist ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel red color resist ink used for a color filter (CF) for a liquid crystal display (LCD), and an L ink using the same.
It relates to a CF for a CD.

[0002]

2. Description of the Related Art Diketopyrrolopyrrole (DPP) is used as a red pigment and dispersed in a photosensitive resin composition containing bisphenolfluorene type epoxy di (meth) acrylate or an acid anhydride polycondensate. Resist inks are known.
This is described in, for example, JP-A-00-19725.

[0003]

However, a red color resist ink using a DPP pigment of the conventional formula is used for LC.
When the CF for D is used for production, there is a problem that needle-like crystals may be generated on the CF surface under high-temperature exposure such as during the ITO sputtering step for forming a transparent conductive film.

An object of the present invention is to provide a red color resist ink which gives the high level of high color saturation without the above-mentioned problems when used in a CF for LCD.

The present inventors have found that DPP pigments have a spectral transmission curve of 550 compared to 4,4'-diamino-1,1'-bianthraquinone, which has been used as a red pigment for red color resist inks. Paying attention to the characteristic that the rising slope appearing at about 600 nm is large, and using a red color resist ink to which this DPP pigment is applied as a red pigment, the overlapping area with the color matching function y (λ) is large. In other words, L, whose lightness Y value has been significantly improved
Research was started in anticipation that a CF for CD could be obtained, and that the tendency to increase the Y value would be further accelerated by using the finely divided DPP product as a red pigment.
However, when the produced color filter was exposed to a high temperature in an ITO sputtering process or the like, there was a problem that needle-like crystals might be generated on the surface.

[0006]

Means for Solving the Problems Accordingly, the present inventors have:
The relationship between the characteristics of the DPP pigment and the crystal growth properties under high temperature exposure was examined. The DPP pigment used had a half width of the intensity peak in the range of 28 to 29 degrees of 2θ in the X-ray diffraction intensity measurement results within a certain range. The present inventors have found that the crystal growth property at a high temperature can be suppressed by selecting the formula (1), thereby completing the present invention.

That is, according to the present invention, in a red color resist ink obtained by dispersing a red pigment in a photosensitive resin composition, the red pigment has a 2θ of 28 as measured by X-ray diffraction intensity.
The intensity peak half width in the range of ~ 29 degrees is 0.600 degrees or more,
Diketopyrrolopyrrole (DP
P) a pigment, and as a photosensitive resin component, (A) a bisphenolfluorene-type epoxy di (meth) acrylate represented by the following formula (1) or (B) an acid anhydride polycondensate represented by the formula (2) And a color filter (CF) produced using the same.

[0008]

Embedded image

Embedded image (However, in the formulas (1) and (2), R is hydrogen or a methyl group)

Hereinafter, the present invention will be described in detail. The red pigment DPP pigment used in the present invention can be produced, for example, as follows. First, crude DPP can be synthesized by reacting p-chlorobenzonitrile and bromoacetate in the presence of zinc powder. Next, DP
After dissolving P in concentrated sulfuric acid as a solvent, throwing it into water to precipitate it to form a pigment, it is taken out as a water-containing cake by filtration, dried, and pulverized to obtain a powdered DPP.
Pigments can be obtained. The X-ray diffraction intensity peak half width is a characteristic value that is inversely proportional to the primary particle size of the pigment. Therefore, it can be controlled by adjusting the primary particle size during pigment production, for example, by adjusting the conditions of the underwater pigmentation step. However, the manufacturing method is not limited to this. 2 in the X-ray diffraction intensity measurement results of the DPP pigment
The intensity peak half width in the range of 28 to 29 degrees of θ is 0.600.
Degrees or more, must be 0.800 degrees or less, preferably 0.7 degrees
It is not less than 00 degrees and not more than 0.800 degrees. The value of this half width is 0.6
If the temperature is less than 00 ° C., the lightness of the cured film decreases, and if it exceeds 0.800 ° C., undesirably, needle crystals may be formed on the surface of the cured film under high temperature exposure. The primary particle size of the DPP pigment is generally
Although it is at least 100 nm, it can be said that the primary particle size of the DPP pigment used in the present invention is lower than that.

The red color resist ink of the present invention is obtained by dispersing the above-mentioned DPP pigment, which is a red pigment, in a photosensitive resin composition. A monomer, an oligomer or a resin as an essential component, and in addition to this, a photopolymerization initiator is usually contained, and it may be any as long as it forms a solid resin in a polymerized and cured state. It may be composed of only components such as unreacted monomers, and may contain other components such as solvents. In the case where the ink is used, an organic solvent for adjusting the viscosity and other additives are often included in order to improve the usability as the ink.

The photosensitive resin component such as a photosensitive monomer or oligomer includes (meth) acrylate (A) represented by the above formula (1) and acid anhydride polycondensate (B) represented by the above formula (2). ) As an essential component, but may include other components. The above (A)
The amount of (B) and (B) is at least 50% by weight of a photosensitive resin component such as a photosensitive monomer or an oligomer, preferably 60 to 60%.
80% by weight. In the above formula (2), n is preferably a number of 1 to 50.

Other photosensitive resin components include, for example, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and ethylene glycol di (meth) acrylate.
Acrylate, diethylene glycol di (meth) acrylate, triethylene glycol (meth) acrylate, tetraethylene glycol di (meth) acrylate, tetramethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolethane tri (meth) ) Acrylate,
Pentaerythritol di (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, glycerol (meth) acrylate, bisphenol A type epoxy (meth) acrylate, bisphenol F type epoxy (meth) acrylate, etc. (Meth) acrylates. Preferably, it is a bifunctional or higher (meth) acrylate. These photosensitive components may be used alone or in combination of two or more. Further, a non-photosensitive resin or monomer may be incorporated in a small amount, for example, about 5 to 40 wt% in the photosensitive resin composition. As such a resin, an epoxy resin is preferably exemplified.

Examples of the photopolymerization initiator include acetophenones such as acetophenone, 2,2'-diethoxyacetophenone, p-dimethylacetophenone and p-tert-butylacetophenone, benzophenone, 2-chlorobenzophenone, p, p Benzophenones such as'-bisdimethylaminobenzophenone; benzoin ethers such as benzoin methyl ether, benzoin isopropyl ether and benzoin butyl ether; 2-methyl-1- [4- (methylthio) phenyl] -2-monforinopropanone- 1,2-benzyl-2-dimethylamino-1- (4-monofoliophenyl)-
Α-Aminoalkylphenones such as butanone-1, and sulfur compounds such as benzyldimethylketal, thioxanthone, 2-chlorothioxanthone, and 2,4-diethylthioxanthone. These photopolymerization initiators may be used alone or in combination of two or more.

As the organic solvent, esters, ketones, polyhydric alcohol derivatives, nitrogen-containing solvents and the like can be used from the viewpoint of excellent dispersibility of the pigment and solubility of the photosensitive resin component. Examples include ethyl acetate, butyl acetate and the like, ketones include cyclohexanone, ethyl butyl ketone, and the like, and polyhydric alcohol derivatives include ethylene glycol monoethyl ether acetate,
Examples thereof include propylene glycol monomethyl ether acetate and the like, and examples of the nitrogen-containing solvent include dimethylformamide.

In the red color resist ink of the present invention, as a method for dispersing a red pigment, DPP, in a photosensitive resin composition, the DPP pigment is dispersed in an organic solvent using a dispersant in advance to prepare the red pigment. A method of preparing a dispersion, mixing and dispersing the dispersion with a composition containing a photosensitive resin component (preferably, a composition excluding a photopolymerization initiator),
A method of directly dispersing the DPP pigment in the composition containing the photosensitive resin component may be mentioned, but the former method is preferable from the viewpoint of the stability of the color resist ink.

When the DPP pigment is dispersed with a dispersant, the dispersant preferably has an effect of imparting fine dispersion stability, and in this sense, a cationic comb graft polymer can be mentioned.

When an ink is prepared by dispersing a DPP pigment, the pigment, dispersant and organic solvent or a photosensitive resin and the like are first kneaded using a roll mill, and then an organic solvent is added and further dispersed using a bead mill. It is preferable to produce an ink from the viewpoint of improving dispersibility such as eliminating coarse particles.

When the DPP pigment is prepared in advance as a red pigment dispersion, the amount thereof and the mixing ratio of the photosensitive resin composition are appropriately selected according to the required exposure sensitivity and developability.
Usually, the former: the latter = 5: 95-3 by weight ratio of solids
Preferably, the ratio is 0:70. In the photosensitive resin composition,
If a solvent or other additives for imparting performance as an ink, for example, a surfactant, a dispersant, and the like are added, the ink becomes the ink of the present invention as it is. If not, some of these additives may be blended as needed to provide the ink of the present invention. The ink thus obtained is suitable as a red ink for CF, and the CF obtained by using this ink has a film obtained by curing this in a pixel. In addition, as a method of producing CF using this ink, a known method can be adopted.

[0019]

Next, the present invention will be described more specifically with reference to examples and comparative examples. <X-ray diffraction spectrum measurement conditions of pigment> Apparatus: Rigaku Denki Co., Ltd., RINT1400 rotor flex type Tube: Cu, tube voltage: 20KV, tube current: 2mA, goniometer: wide-angle goniometer, sampling width: 0.010 ° ,
Scanning speed: 1.000 ° / min, scanning axis: 2θ / θ, divergent slit: 1 °, scattering slit: 1 °, light receiving slit: 0.15mm,
Attachment: Standard sample holder

<DPP Pigment> The DPP pigment used is represented by the following formula (3).

Embedded image

A: 2θ = 28 to 2 in X-ray diffraction spectrum
A DPP pigment having a peak intensity at 9 degrees with a half width of 0.705 degrees. B: A DPP pigment having a half-width of a peak intensity at 2θ = 28 to 29 ° in the X-ray diffraction spectrum of 0.720 °. C: A DPP pigment having a half-width of a peak intensity at 2θ = 28 to 29 ° in the X-ray diffraction spectrum of 0.886 °. The measurement results of the X-ray diffraction spectrum and the half width of A, B and C are shown in FIGS. 1, 2 and 3, respectively.

<Dispersant> Dis.-1 50 wt% solution of a cationic comb graft polymer having an amine value of 7.7 <Organic solvent> S-1 Propylene glycol monomethyl ether acetate

Next, the conditions for evaluating the properties of the prepared pigment dispersion (bead mill dispersion: dispersion in the table) and the color resist ink coating film are shown below. <Evaluation of Properties of Pigment Dispersion><Viscosity> After the dispersion, the red pigment dispersion was allowed to stand at room temperature for 24 hours in a constant temperature water bath at 23 ° C. for 40 minutes, and then a B-type viscometer [manufactured by Tokimec Co., Ltd.] : Product name BL type), rotation speed 6
The viscosity was measured at 0 rpm at a temperature of 23 ° C. <TI value (thixotropic index value)> Revolution 6
The value obtained by dividing the viscosity at rpm by the viscosity at 60 rpm was defined as the TI value. The smaller this value is, the closer to 1, the smaller the thixotropy (the larger the Newtonian fluidity), the better. <Average particle size> The average particle size is 0.003 g of a red pigment dispersion.
Was diluted with 40 g of an organic solvent propylene glycol monomethyl ether acetate, and subjected to ultrasonic dispersion in an ultrasonic cleaner for 90 seconds to prepare a measurement sample. A laser Doppler particle size distribution analyzer [manufactured by Otsuka Electronics Co., Ltd .: trade name ELS-
800].

<Evaluation of Properties of Color Resist Ink Coating Film><Heat Crystal Precipitation> The ink-coated plate was placed in a hot air oven.
After exposure for 1 hour at 50 ° C, the surface condition of the ink coating film was observed using a reflection type polarizing microscope with a magnification of 400 times. (△), remarkably recognized and unusable (x). <Lightness Y value and chromaticity (x, y)> The values were measured using a chromaticity meter (trade name: Color Analyzer TC-1800MK2, manufactured by Tokyo Denshoku Co., Ltd.). <Film thickness> The thickness was measured using a stylus type surface roughness meter (manufactured by Tokyo Seimitsu Co., Ltd.).

Examples 1 and 2 and Comparative Example 1 [Preparation of pigment dispersion (bead mill dispersion) and evaluation of properties]
After blending the bead mill dispersion raw material with the composition shown in Table 1 in a 2 L plastic container, using a homomixer, mixing at 2,000 rpm for 1 hour, and then performing pigment dispersion using a disk rotating bead mill to prepare a bead mill dispersion. .

Table 1 shows the amounts (g), the ratios, etc. of the compounds. Here, the compounding ratio of the dispersant was unified to 35.0 wt% based on the pigment = 100 wt%. The properties of this bead mill dispersion were evaluated according to the method described above. Table 1 shows the results of the characteristic evaluation.

[0027]

[Table 1]

The average particle size (secondary particle size) was 129
Atomization of less than nm was sufficiently achieved. Example viscosity,
The TI value was good and the fine dispersibility was good.

[Preparation of Color Resist Ink Coating Film and Evaluation of Properties] Since the atomization state and dispersion stability of the pigment dispersion (bead mill dispersion) were good as described above, the color resist ink and its coating film were prepared. Then, the characteristics were evaluated. As the resin component, an acid anhydride polycondensate of bisphenol fluorene type epoxy di (meth) acrylate represented by the formula (2) [manufactured by Nippon Steel Chemical Co., Ltd .: trade name: V-259ME, solid content: 55.3%] 150 9.9 g, dipentaerythritol hexaacrylate 35.8 g, and biphenol type epoxy resin (trade name: Epicoat YX-4000HK, manufactured by Yuka Shell Epoxy Co., Ltd .: 17.9 g), and 2-methyl as a photopolymerization initiator component -1- [4- (methylthio) phenyl] -2-
3.6 g of monforinopropane-1, 1.9 g of 4,4'-bis-diethylaminobenzophenone, and 5.4 of 2,4-trichloromethyl- (4'-methoxystyryl) -6-triazine.
g of this resin was dissolved in 294.8 g of organic solvent S-1 to prepare a photosensitive resin composition having a solid content of 29.2%.

Next, red color resist inks were prepared at the ratios shown in Table 1. In all Examples and Comparative Examples, the weight ratio of pigment / resin (where resin is resin + dispersant) was constant at 0.49 when the ink was used, and the solid content concentration was 20.0% by weight. And constant.

This color resist ink was applied onto a 5 inch square, 1 mm thick blue glass plate using a spin coater. The rotation speed of the spin coater at this time was adjusted so that the ink film thickness was 1.5 μm (after post-baking), and the time was 10 seconds. Next, this ink-coated glass plate was pre-baked. The prebaking conditions were 80 ° C. for 3 minutes. Next, after placing a photomask on the glass plate coated with the pre-baked ink, UV exposure at 300 mj / cm ² was performed. This UV-irradiated ink-coated glass plate was alkali-developed with a 0.4% aqueous sodium carbonate solution for 25 seconds. The glass plate coated with the alkali developing ink was post-baked at 230 ° C. for 30 minutes to form an ink coating film as a model red color filter. Using the thus-prepared ink coating film as a sample, the color characteristics of the color resist ink were evaluated according to the method described above. Table 1 shows the results.

The ink coating films prepared using the color resist inks obtained in Examples 1 and 2 were exposed to a temperature of 250 ° C. for 1 hour. )Met. In addition, other characteristics such as the brightness Y value also showed excellent values. However, in Comparative Example 1,
The thermal crystal deposition property was extremely poor (x).

[0033]

The red color resist ink of the present invention is
It is extremely useful for high-quality color filters because of its remarkably excellent heat-resistant crystal deposition property when the coating film is exposed to high temperatures.

[Brief description of the drawings]

FIG. 1 X-ray diffraction chart of diketopyrrolopyrrole pigment A

FIG. 2 X-ray diffraction chart of diketopyrrolopyrrole pigment B

FIG. 3 X-ray diffraction chart of diketopyrrolopyrrole pigment C

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03F 7/027 502 G03F 7/027 502 7/038 501 7/038 501 F term (reference) 2H025 AA10 AA11 AB13 AC01 AD01 BC13 BC43 BC74 BC83 CC11 2H048 BA48 BB42 4J027 AB03 AB09 AB26 AC03 AC06 AE02 AE07 AJ08 BA08 BA10 BA20 BA23 BA24 BA25 BA26 BA27 CB10 CC05 CD10 4J039 AD10 BC16 BC51 BC64 BE01 EA15 EA29 GA17

Claims (2)

[Claims] 1. A red color resist ink comprising a red pigment dispersed in a photosensitive resin composition, wherein the red pigment is X
Is a diketopyrrolopyrrole pigment having a half width of an intensity peak in the range of 28 to 29 degrees of 2θ in X-ray diffraction intensity measurement of not less than 0.600 degrees and not more than 0.800 degrees, and is represented by the formula (1) as a photosensitive resin component. A red color resist comprising at least one selected from the group consisting of bisphenol fluorene type epoxy di (meth) acrylate represented by formula (I) and an acid anhydride polycondensate of bisphenol fluorene type epoxy di (meth) acrylate represented by formula (2): ink. Embedded image Embedded image (However, in the formulas (1) and (2), R is hydrogen or a methyl group) 2. A color filter produced by using the red color resist ink according to claim 1.