JPH05331378A - Pigment composition for color filter and color filer - Google Patents

Abstract

PURPOSE:To obtain a pigment compsn. which can provide various kinds of spectral properties and is useful for producing a color filter enabling a highquality liq. crystal display. CONSTITUTION:A pigment compsn. contains an org. polymer and a yellow anthraquinone pigment. A pref. org. polymer is prepd. from a photosensitive resin comprising a photopolymerizable compd. having at least one ethylenicaly unsatd. double bond, a photopolymn. initiator, and another resin. An example of the pigment is a compd. of formula I [wherein X is R<1>, R<2>, R<3>, or R<4>; R<1> is alkyl or alkenyl; R<2> is -OR<1> or -SR<1>; R<3> is -NHR<1>; and R<4> is a group of formula II (wherein the phenyl group may be substd. by halogen, nitro, etc.; and n is 0, 1, or 2)].

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a color filter composition and a color filter. More specifically, it relates to a photopolymerizable composition for a color filter used in a liquid crystal display device or the like and having excellent optical properties, and a color filter obtained from the photopolymerizable composition.

[0002]

2. Description of the Related Art Color filters used in color liquid crystal display devices and the like, which are being converted from the CRT system, are
It is composed of fine pixels colored in at least two kinds of hues and a black matrix provided for the purpose of blocking light between the pixels. As a method for producing a color filter, a dyeing method using a dye, a dye internal addition method, a pigment internal addition method using a pigment, an electrodeposition method, an electric field micelle method,
Printing method and the like. Among these methods, the method using a pigment is characterized in that it has excellent heat resistance and light resistance, and that the process for producing a color filter is simpler than the dyeing method.

However, in the case of liquid crystal display, 1990
As is clear from the literature reported at the Annual Color Engineering Conference, in the method using a pigment, the polarized light obtained through the polarizing plate is partially scattered by the pigment particles because the pigment exists as particles in the color filter pixel. However, there is a problem in that the liquid crystal display quality, particularly the contrast, is lower than that of the method using a dye, and the property is remarkable when a yellow pigment is used.

[0004]

It has been desired to develop a pigment composition for producing a color filter having a variety of spectral characteristics and high liquid crystal display quality.

[0005]

The present inventors have made diligent efforts to find a method for producing a color filter having a variety of spectral characteristics as described above and having a good liquid crystal display quality, and as a result, a specific pigment composition has been obtained. The present invention has been found out that the method of using a product satisfies the above characteristics.

That is, the present invention provides: (1) a pigment composition for a color filter comprising an organic polymer and an anthraquinone yellow pigment (2) the organic polymer contains at least an ethylenically unsaturated double bond The pigment composition for a color filter according to the above item (1), which is a photosensitive resin comprising one or more photopolymerizable compounds, a photopolymerization initiator, and optionally other resins, and (3) a film-forming polymeric binder and The pigment composition for a color filter according to item (1), which contains a heat-polymerizable resin, and / or (4) an anthraquinone-based yellow pigment, as described in item (1) to (3), represented by the following formula (1). Pigment composition for color filter

[0007]

[Chemical 4]

[Wherein X is a group R ₁ , R ₂ , R ₃ , or R
₄ , R ₁ is alkyl or alkenyl, R ₂ is —O
R ₁ or —SR ₁ , R ₃ is —NHR ₁ , and R ₄ is the formula (2).

[0009]

[Chemical 5]

(Wherein the phenyl group is halogen, nitro,
1 to 3 each independently may be substituted with a substituted amino, alkyl, alkoxy, or alkyl sulfide group, and n
Represents 0, 1 or 2. ) Means a group. ] (5)
The pigment composition for color filters according to the above (1) to (3), wherein the anthraquinone yellow pigment is a yellow pigment represented by the following formula (3).

[0011]

[Chemical 6]

(Wherein the phenyl group is halogen, nitro,
1 to 3 each independently may be substituted with a substituted amino, alkyl, alkoxy, or alkyl sulfide group, and n
Represents 0, 1 or 2. ) (6) (1) to (5) above
A color filter obtained by using the pigment composition for a color filter according to 1.

The pigment composition for a color filter of the present invention and the color filter obtained therefrom will be described in more detail.

In the present invention, various anthraquinone type yellow pigments can be used, but as a particularly preferred example, a yellow pigment represented by the following formula (1),

[0015]

[Chemical 7]

[Wherein X is a group R ₁ , R ₂ , R ₃ or R
₄ , R ₁ is alkyl or alkenyl, R ₂ is —O
R ₁ or —SR ₁ , R ₃ is —NHR ₁ , and R ₄ is the formula (2).

[0017]

[Chemical 8]

(Wherein the phenyl group is halogen, nitro,
1 to 3 each independently may be substituted with a substituted amino, alkyl, alkoxy, or alkyl sulfide group, and n
Represents 0, 1 or 2. ) Means a group. 〕as well as,
A yellow pigment represented by the following formula (3),

[0019]

[Chemical 9]

(Wherein the phenyl group is halogen, nitro,
1 to 3 each independently may be substituted with a substituted amino, alkyl, alkoxy, or alkyl sulfide group, and n
Represents 0, 1 or 2. ) Is mentioned. These yellow pigments may be used in combination with other pigments, and examples of the other pigments include phthalocyanine pigments, azo pigments, isoindolinone pigments, perylene pigments, quinacridone pigments, dioxazine pigments, Known pigments such as pyrrolopyrrole pigments can be used. These may be pigments described in Color Index.

The anthraquinone yellow pigment and other pigments to be used in combination are adjusted to have a particle size of 1/2 or less of the wavelength of transmitted light, that is, 200 nm or less, and more preferably 50 to 140 nm, in order to transmit visible light. Those that are preferred. The anthraquinone yellow pigment and other pigments used in combination with the pigment are usually dispersed together with a dispersant in a disperser such as a sand mill or a triple roll, and then added to the resin system.
The pigment is mixed in the resin in a proportion of 10 to 50% by weight.

The organic polymer used in the present invention includes
Since this is the main resin forming the color filter, it must be a polymer that is colorless and transparent and has excellent heat resistance and light resistance. Specific examples thereof include the following.

Epoxy resins, melamine resins, acrylic resins, polyimide resins and their precursors, polyamic acid resins, polyester resins, unsaturated polyester resins, polycarbonate resins, photosensitive monomers and oligomers having a (meth) acryloyl group, Other resins may be mentioned.

Among the epoxy resins, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, polycarboxylic acid glycidyl ester, polyol polyglycidyl ether,
Aliphatic or alicyclic epoxy resin, amine epoxy resin,
Examples thereof include triphenol methane type epoxy resin and dihydroxybenzene type epoxy resin. Examples of the melamine resin include polymethylol melamine resin and polymethylol benzoguanamine resin.

In the present invention, a preferable organic polymer is a photosensitive resin comprising a photopolymerizable compound having at least one ethylenically unsaturated double bond, a photopolymerization initiator, and optionally other resin. Specific examples of the photopolymerizable compound having at least one ethylenically unsaturated double bond include a photosensitive monomer having a (meth) acryloyl group and an oligomer, and specific examples thereof include ethyl acrylate, butyl acrylate, Acrylic or methacrylic alcohols such as hydroxyethyl acrylate, hydroxyethyl methacrylate, ethylene glycol dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate. Esters of acids; polyesters obtained by reacting (meth) acrylic acid with a polyester prepolymer obtained by condensing a polyhydric alcohol with a monobasic acid or a polybasic acid Le (meth) acrylate; polyol group and after reacting the compound having two isocyanate groups (meth)
Polyurethane (meth) acrylate obtained by reacting acrylic acid; bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, polycarboxylic acid glycidyl ester, polyol polyglycidyl ester, aliphatic or alicyclic epoxy resin Ordinary photopolymerizable compounds such as epoxy (meth) acrylate obtained by reacting (meth) acrylic acid with an epoxy resin such as amine epoxy resin, triphenol methane type epoxy resin, dihydroxybenzene type epoxy resin.

At least one ethylenically unsaturated double bond
A photosensitive monomer having both a (meth) acryloyl group and a carboxylic acid as a photopolymerizable compound having three or more, and
Oligomers can also be used, and specific examples thereof include bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolac type epoxy resin, polycarboxylic acid glycidyl ester, polyol polyglycidyl ester, aliphatic or alicyclic epoxy resin, amine. Epoxy groups such as epoxy resin, triphenol methane type epoxy resin, dihydroxybenzene type epoxy resin and (meta)
Epoxy (meth) acrylate-carboxylic acid adduct obtained by reacting an acid anhydride with a hydroxy group obtained by reacting acrylic acid; ethylene, propene, isobutylene, styrene, vinylphenol, acrylic copolymerizable with maleic anhydride Half-esterification by reacting maleic anhydride part of copolymer with acid, acrylic acid ester, acrylamide, etc. monomer with alcoholic hydroxy group acrylate such as hydroxyethyl acrylate or epoxy group acrylate such as glycidyl methacrylate. Compounds obtained by further reacting acrylic acid with the -OH group of a copolymer of acrylic acid, an acrylic ester and an acrylate having an alcoholic hydroxy group such as hydroxyethyl acrylate.

Other resins as a component of the photosensitive resin include a film-forming polymer binder. As the film-forming polymer binder, for example, polymethacrylic acid ester or its partial hydrolyzate, polyvinyl acetate or its hydrolyzate, polyvinylphenol, phenol novolak, polystyrene, polyvinyl butyral, polychloroprene, polychlorinated Vinyl, chlorinated polyethylene, chlorinated polypropylene, polyvinylpyrrolidone, a copolymer of styrene and maleic anhydride or a half ester thereof,
A copolymer having a glass transition point of 35 ° C. or higher selected from a group of copolymerizable monomers such as acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, acrylamide, and acrylonitrile is used. These film-forming polymer binders are preferably used in a range that does not reduce the polymerization rate of the photopolymerizable compound,
Usually, it is used in the range of 0 to 80% by weight, preferably 10 to 60% by weight, based on the photopolymerizable compound.

The photopolymerization initiator used in the photosensitive resin in the present invention may be various photopolymerization initiators alone or in combination, but generally, a type in which a pigment is dispersed in the photopolymerizable resin is used. In the above colored photopolymerizable resin composition, the ultraviolet rays necessary for the photopolymerization initiator to generate radicals are absorbed by the pigment, so that the radicals are not sufficiently generated and the polymerization tends to be insufficient.

Therefore, the photopolymerization initiator is a highly sensitive compound,
Alternatively, a composition is required. Specific examples of such compounds and compositions include benzyl; benzoin ether;
Benzoin isobutyl ether; benzoin isopropyl ether; benzophenone; benzoylbenzoic acid; methyl benzoylbenzoate; 4-benzoyl-4'-methyldiphenyl sulfide; benzylmethyl ketal;
2-n-Butoxyethyl-4-dimethylaminobenzoate; 2-chlorothioxanthone; 2,4-diethylthioxanthone; 2,4-diisopropylthioxanthone; dimethylaminomethylbenzoate; p-isoamyl dimethylaminobenzoate; 3,3'- Dimethyl-4-
Methoxybenzophenone; 2,4-dimethylthioxanthone; 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one; 1-hydroxycyclohexylphenyl ketone; 2-hydroxy-2-methyl-1-phenyl Propan-1-one; 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one; isopropylthioxanthone; methylbenzoylformate; 2-methyl-1- [4- (methylthio) phenyl] -2-Morpholinopropane-1
--On, 2,2'-bis (o-chlorophenyl) -4,
4 ', 5,5'-tetraphenylbisimidazolyl;
2,2'-bis (o-chlorophenyl) -4,4 ',
5,5'-tetra- (p-methoxyphenyl) bisimidazolyl and the like may be used, and these may be used alone or in combination, and the total weight thereof is 0.1 to 10 relative to the photopolymerizable compound. %, Preferably 0.1 to 5% by weight.

The pigment composition for a color filter of the present invention can be obtained by mixing the above-mentioned finely divided anthraquinone yellow pigment, an organic polymer and, if necessary, other components. If necessary, a dispersion treatment may be performed during the mixing, or a step of filtering to remove impurities may be employed.

A color filter using the pigment composition for a color filter of the present invention is usually prepared as follows. That is, the pigment composition for a color filter of the present invention is diluted with an organic solvent such as ethyl cellosolve acetate so as to have a preferable viscosity according to the coating method. After diluting with a solvent of (1), the film thickness when dried on a substrate such as a glass plate by a coating machine such as a spinner, roll coater or gravure printing machine is usually 1.0 to After coating so as to have a thickness of 3.0 μm, a color filter is obtained through each process such as drying, light irradiation, and development.

The pigment composition for a color filter of the present invention is characterized by having good dispersion stability, excellent spectral characteristics, and a color filter having a small depolarizing effect.

[0033]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Preparation Example 1 of Pigment Dispersion Paste 1 To 20 g of an anthraquinone yellow pigment represented by the following formula (4) (hereinafter referred to as yellow pigment 1), 4 g of a sorbitan fatty acid ester compound was added as a dispersant, and further ethyl cellosolve acetate. 76 g was added and dispersed by a sand mill. Thus, a finely divided pigment dispersion paste having an average particle diameter of 120 nm was obtained.

[0035]

[Chemical 10]

Preparation Example 2 of Pigment Dispersion Paste To 20 g of an anthraquinone yellow pigment represented by the following formula (5) (hereinafter referred to as yellow pigment 2), 4 g of the above dispersant was added as a dispersant, and 76 g of ethyl cellosolve acetate was further added. In addition, dispersion was performed with a sand mill.

[0037]

[Chemical 11]

Pigment Dispersion Paste Preparation Examples 3 to 8 The combinations of pigments shown in Table 1 below were dispersed in the same manner as in Pigment Dispersion Paste Preparation Example 1.

[0039]

The average number distribution of the pigment particles dispersed here was 200 nm or less.

Example 1 15 g of the pigment dispersion paste obtained in Preparation Example 1 of the above pigment dispersion paste, 6.5 g of SMA2625 (trade name, styrene-maleic acid half ester, manufactured by Arco Chemical),
3.5 g of dipentaerythritol hexaacrylate,
Irgacure 369 (trade name, manufactured by Ciba Geigy,
Photopolymerization initiator) 0.4 g, Kayacure DETX (trade name, manufactured by Nippon Kayaku, thioxanthone photopolymerization initiator)
1 g and 20 g of ethyl cellosolve acetate were mixed, stirred, and ultrasonically dispersed for 10 minutes to obtain a pigment composition for a color filter of the present invention.

Examples 2 to 8 In the same manner as in Example 1, the pigment dispersion pastes obtained in the above-described pigment dispersion paste preparation examples 2 to 8 were used to obtain pigment compositions for color filters of the present invention.

Comparative Example C. I. Pigment Green 36 15g
And C.I. I. Pigment Yellow 835
4 g of the dispersant and 76 g of ethyl cellosolve acetate were added to a mixture of g and dispersed by a sand mill.

15 g of this pigment paste, SMA26
25 6.5 g, dipentaerythritol hexaacrylate 3.5 g, Irgacure 369 0.4
g, Kayacure DETX 0.1 g, and ethyl cellosolve acetate 20 g were mixed, stirred, and ultrasonically dispersed for 10 minutes to obtain a comparative pigment composition for a color filter.

Examples 9 to 16 The pigment compositions for color filters obtained in Examples 1 to 8 and Comparative Example were coated on a glass substrate (manufactured by Conning Co.) so that the film thickness when dried was 2 μm. , Apply with spinner,
Dried. Then, after exposing to 100 mj with an ultra-high pressure mercury lamp, post-baking was performed at 200 ° C. for 20 minutes to obtain a film thickness of 2
A color filter of the present invention and a comparative color filter having a size of μm was obtained. With respect to the color filters obtained in Examples 9 to 16 and Comparative Example, the depolarization degree defined as follows was measured, and the results are shown in Table 2.

Depolarization ratio A color filter is placed between two polarizing plates, and the luminance ratio between when the polarization axes are parallel and when the polarization axes are vertical is defined as the contrast. Next, when the color filter is placed between the two polarizing plates and when it is placed outside, the same contrast can be obtained if there is no polarization anomaly (this is called depolarizing action) in the color filter. The ratio of the contrast when the light is placed inside the two polarizing plates to the time when the light is placed inside is defined as the depolarization degree that represents the degree of the depolarization effect. The closer the depolarization degree is to 1, the smaller the depolarization effect, and the better the color filter.

[0047]

As is apparent from the table, the color filter obtained by using the resin composition for a color filter of the present invention has a small depolarizing effect.

[0049]

The dispersion stability is excellent and the spectral characteristics are excellent.
A pigment composition for a color filter which gives a color filter with less depolarizing effect was obtained.

Claims (6)

[Claims] 1. A pigment composition for a color filter comprising an organic polymer and an anthraquinone yellow pigment. 2. The photopolymerizable compound according to claim 1, wherein the organic polymer is a photopolymerizable compound having at least one ethylenically unsaturated double bond, a photopolymerization initiator, and optionally other resin. Pigment composition for color filter 3. A pigment composition for a color filter according to claim 1, which contains a film-forming polymer binder and / or a thermopolymerizable resin. 4. The color filter pigment composition according to claim 1, wherein the anthraquinone yellow pigment is represented by the following formula (1): [Wherein X is a group R ₁ , R ₂ , R ₃ or R ₄ , and R
₁ is alkyl or alkenyl, R ₂ is -OR ₁ or -S
R ₁ and R ₃ are —NHR ₁ and R ₄ is of the formula (2) (In the formula, the phenyl group is halogen, nitro, substituted amino,
It may be independently substituted with 1 to 3 alkyl, alkoxy or alkyl sulfide groups, and n represents 0, 1 or 2. ) Means a group. ] 5. The pigment composition for a color filter according to claim 1, wherein the anthraquinone yellow pigment is a yellow pigment represented by the following formula (3). (In the formula, the phenyl group is halogen, nitro, substituted amino,
It may be independently substituted by 1 to 3 alkyl, alkoxy or alkyl sulfide groups, and n represents 0, 1 or 2. ) 6. A color filter obtained by using the pigment composition for a color filter according to claim 1.