JPH1060360A - Pigment dispersion and coating agent composition containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pigment dispersion showing improved microdispersion stability even when the concentration of the pigment in a nonaqueous solvent is high by using a novel substantially colorless pigment dispersant being not a colorant derivative. SOLUTION: This invention provides a pigment dispersion containing a pigment, a solvent, a pigment dispersant and optionally a binder resin, wherein the pigment dispersant is a graft copolymer comprising at least 10mol% structural units represented by formulas I and/or II (X<1> and X<2> are each a 2-4C divalent hydrocarbon group; i and j are each 1-100; Y is a 2-20C divalent hydrocarbon group; R<1> and R<4> are each H or methyl; Z<1> and Z<2> are each a 1-20C monovalent active-hydrogen free monovalent organic group bonded to X<1> , X<2> or the α-carbon of the carbonyl through any of O, N and S; and so forth) and at least 10mol% structural units represented by formulas III and/or IV (R<6> and R<10> are each H or methyl; and so forth) and having a weight-average molecular weight of 3,000-100,000 and is used in an amount of 0.2 pt.wt. per 100 pts.wt. pigment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pigment dispersion using a non-aqueous solvent in the technical fields of pigment dispersion resists, inks, paints and the like, and a coating composition using the same.
Particularly, it is useful for a pigment-dispersed resist suitably used for manufacturing a color filter for liquid crystal display.

[0002]

2. Description of the Related Art Generally, organic and inorganic pigments are widely used in pigment-dispersed resists, inks, paints, and the like for the purpose of coloring, shading, preventing rust, protecting inner layers, and the like. These coated and printed materials are required to have high optical density, coloring power, transparency, or high surface smoothness. Furthermore, sufficient fluidity and the like required during application, printing or handling are required, and these performances must be maintained even after long-term storage. For this purpose, the dispersion stability must be excellent even if the pigment particles are miniaturized and contained at a high concentration. However, even if the pigment particles are once finely dispersed, they are easily re-agglomerated, so that it is often difficult to obtain a stable fine dispersion.

[0003] In particular, in the field of pigment-dispersed resists in which the pigment particles are becoming finer due to the recent demand for higher transmittance and higher contrast of visible light for color liquid crystal display devices, the pigment particle diameter is at least visible. Since it is necessary to reduce the light wavelength or less, the specific surface area of the pigment particles becomes considerably larger than usual, and it is difficult to obtain a stable fine dispersion. In addition, since two or more pigments are mixed and used in each pigment-dispersed resist to obtain a spectrum suitable for R (red), G (green), and B (blue) pixels, heteroaggregation may occur. It is easy to occur and dispersion is more difficult.

To solve these problems, various methods using a pigment dispersant have been developed. For example, Japanese Patent Application Laid-Open No. 60-237403 discloses a method in which a derivative of an organic pigment or dye having a basic functional group or the like is used as a pigment dispersant.

[0005] However, this method has a good effect on the pigment dispersing effect, but has a problem that its application range is limited because the color tone of the pigment-dispersed resist changes due to coloring of the pigment dispersant itself. there were.

JP-A-3-212601 and the like disclose an ionic or nonionic surfactant, specifically, a long-chain alkylamine acetate, a quaternary ammonium salt, a polymer polycarboxylic acid, A method using a polyoxyethylene derivative, a sorbitan ester of a long-chain fatty acid, or the like as a pigment dispersant is disclosed.

However, this method has a certain effect in stabilizing the dispersion of the pigment, but still cannot provide a satisfactory effect.

[0008] Due to these problems, the selection and combination of pigments is limited, and at present it is necessary to use pigments with insufficient pigment dispersion stability.

[0009]

The present invention has been made to solve these problems. That is, by using a substantially colorless novel pigment dispersant that is not a pigment derivative, to provide a pigment dispersion having improved fine dispersion stability even at a high pigment concentration in a non-aqueous solvent, and using the same. The present invention provides a coating composition.

[0010]

Means for Solving the Problems As a result of repeated studies to solve the above problems, the present inventors have found that the above problems can be solved by the following specific compound group, and have completed the present invention. Was. That is, the present invention provides (A) a pigment dispersion having a weight average molecular weight of 3,000 to 100,000 as a pigment dispersant in a pigment dispersion containing a pigment, a solvent, a pigment dispersant, and, if necessary, a binder resin. And the compound represented by the general formula (1) and / or
Or at least 10 structural units represented by the general formula (2)
% Of the graft copolymer containing at least 10 mol% of the structural unit represented by the general formula (3) and / or the general formula (4) with respect to 100 parts by weight of the pigment. .2 parts by weight.

[0011]

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(Wherein, X ¹ represents a divalent hydrocarbon group having 2 to 4 carbon atoms, i represents an integer ranging from 1 to 100, and Y represents a divalent hydrocarbon group ranging from 2 to 20 carbon atoms. A certain divalent hydrocarbon group, R ¹ and R ² each independently represent a hydrogen atom or a methyl group, and Z ¹ has no active hydrogen connected to X ¹ by any of oxygen, nitrogen and sulfur atoms (Indicating a monovalent organic group having 1 to 20 carbon atoms)

[0013]

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(Wherein, X ² represents a divalent hydrocarbon group having 2 to 4 carbon atoms, j represents an integer ranging from 0 to 100, and Z ² represents any of oxygen, nitrogen and sulfur atoms. A monovalent group having 1 to 20 carbon atoms having no active hydrogen connected to X ² (when j ≠ 0) or the α-carbon atom of the carbonyl group (when j = 0) Is an organic group represented by R
³ and R ⁴ each independently represent a hydrogen atom or a methyl group;
⁵ represents a monovalent hydrocarbon group having 1 or 2 carbon atoms)

[0015]

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(Wherein, R ⁶ represents a hydrogen atom or a methyl group;
R ⁷ represents a hydrogen atom or a halogen atom, and R ⁸ and R ⁹ each independently represent a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, an alkoxy group or a halogen atom.

[0017]

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(Wherein R ¹⁰ represents a hydrogen atom or a methyl group;
R ¹¹ represents a single bond (meaning that the phenyl group is directly bonded to the oxygen atom adjacent to the carbonyl group) or a methylene group. In the present invention, (B) the pigment according to the above (A) The present invention relates to a coating composition using a dispersion.

Further, the present invention provides (C) a photocurable pigment-dispersed resist for a color filter, which comprises the pigment dispersion described in (A) above, a radical polymerizable compound, and a photopolymerization initiator. Composition.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, the use of the above-mentioned specific graft copolymer as a pigment dispersant suppresses pigment re-aggregation and structural viscosity of a pigment fine dispersion for a long period of time. As a result, the optical density, coloring power, transparency, or surface smoothness of the coated or printed material such as a pigment-dispersed resist, ink, or paint are increased, and sufficient fluidity required at the time of coating, printing, or handling is obtained. be able to.

Hereinafter, the pigment dispersion containing a graft copolymer as a pigment dispersant in the pigment dispersion of the present invention containing a pigment, a solvent, a pigment dispersant and, if necessary, a binder resin, and the use of the same. The coating composition used will be described in detail.

The graft copolymer of the present invention has the following general formula (1):

[0023]

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(Wherein R ¹ and R ² are the same as above) and / or general formula (6):

[0025]

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(Wherein R ³ and R ⁴ are the same as described above)
90 mol%, general formula (7):

[0027]

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Wherein R ⁶ , R ⁷ , R ⁸ and R ⁹ are the same as described above, and / or a general formula (8):

[0029]

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(Wherein R ¹⁰ and R ¹¹ are the same as described above) in an amount of from 10 to 90 mol% of the monomer represented by the formula (1), if necessary, having no functional group highly reactive with an epoxy group. Using a radical polymerization initiator such as a peroxide or an azo compound, a copolymer containing an epoxy group is obtained from 0 to 80 mol% of another ethylenically unsaturated monomer by a conventional method. A general formula (11) or (1)
By reacting a compound having a carboxyl group at one end represented by 2), or (2) a general formula (9):

[0031]

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(Wherein R ¹ , R ² , X ¹ , i, Y, and Z ¹ are the same as described above) and / or a general formula (1)
0):

[0033]

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(Wherein R ³ , R ⁴ , R ⁵ , X ² , j and Z ² are the same as those described above),
And 10 to 90 mol% of the monomer represented by the general formula (7) and / or the monomer represented by the general formula (8), and if necessary, a functional group highly reactive with an epoxy group. 0-80 mol% of other ethylenically unsaturated monomers not having
And a radical polymerization initiator such as a peroxide or an azo compound, and reacted by a conventional method. The epoxy group of the copolymer obtained in the above method (1) is reacted with a compound having a carboxyl group at one terminal represented by the following general formula (11) or (12) to form a compound represented by the general formula (1) or ( In the reaction for obtaining the structural unit represented by 2), or in the method (2), the epoxy group of the epoxy group-containing ethylenically unsaturated monomer is substituted with a carboxyl at one terminal represented by the following general formula (11) or (12). A compound having a group represented by the general formula (9) or (1)
The reaction for obtaining the monomer represented by the formula (0) is carried out by using a solvent as necessary, and optionally using a catalyst such as an aliphatic amine, an aromatic amine or an ammonium salt at 60 to 160 ° C.
Heating. The progress of the reaction can be monitored by measuring the molecular weight, epoxy equivalent and the like by gel permeation chromatography (GPC).

In the structural unit represented by the general formula (3), examples of the halogen atom represented by R ⁷ include a chlorine atom. Examples of the hydrocarbon group having 1 to 5 carbon atoms represented by R ⁸ or R ⁹ include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl and t-butyl.
Alkyl groups such as butyl, pentyl and the like, as an alkoxy group having 1 to 5 carbon atoms, for example, methoxy, butoxy, etc., as an aryloxy group having 6 to 10 carbon atoms, for example, phenoxy, etc. For example, a fluorine atom, a chlorine atom, a bromine atom and the like can be mentioned.

Among the monomers used for producing the graft copolymer of the present invention, styrene derivatives of the monomers represented by the general formula (7) include vinyltoluene, α-methylstyrene and dimethylstyrene. Alkyl-substituted styrenes such as ethyl styrene, isopropyl styrene and t-butyl styrene, halogen-substituted styrenes such as chlorostyrene, dichlorostyrene, bromostyrene and fluorostyrene, alkoxystyrenes such as methoxystyrene and butoxystyrene, and aryloxys such as phenoxystyrene. Styrene, β-chlorostyrene and the like can be used.

Examples of the monomer represented by the general formula (8) include benzyl (meth) acrylate and phenyl (meth) acrylate.

Examples of the epoxy group-containing ethylenically unsaturated monomer represented by the general formula (5) or (6) include glycidyl (meth) acrylate and 2,3-epoxy-2-methylpropyl (meth) acrylate. Can be used.

Other ethylenically unsaturated monomers that do not have a functional group highly reactive with the epoxy group used as necessary include carboxyl groups, phenolic hydroxyl groups, primary amino groups, and secondary amino groups. An ethylenically unsaturated monomer having no functional group highly reactive with an epoxy group such as an amino group can be used. For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) Acrylate, dodecyl (meth)
Alkyl esters of (meth) acrylic acid such as acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, norbornyl (meth) acrylate, and cyclic ether groups such as tetrahydrofurfuryl (meth) acrylate Having (meth) acrylate, 2-hydroxyethyl (meth)
(Meth) acrylates having an aliphatic alcoholic hydroxyl group such as acrylate, (meth) acrylates having a tertiary amino group such as dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate, methyl vinyl ether, dodecyl vinyl ether; Examples thereof include vinyl ethers having an aliphatic alcoholic hydroxyl group such as propenyl ether propylene carbonate, and allyl esters of various acids such as allyl acetate.

The structural unit represented by the general formula (1) or (2) in the graft copolymer of the present invention is an epoxy group-containing ethylenically unsaturated compound represented by the general formula (5) or (6). Structural units derived from monomers and general formula (11):

[0041]

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(Wherein X ¹ , i and Z ¹ are the same as described above) or the general formula (12):

[0043]

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(Wherein R ⁵ , X ² , i and Z ² are the same as those described above) or a compound having a carboxyl group at one terminal, or represented by the general formula (5) or (6) The epoxy group-containing ethylenically unsaturated monomer and the general formula (1)
It can be obtained from a monomer obtained from the compound having a carboxyl group at one terminal represented by 1) or (12).

The compound having a carboxyl group at one terminal represented by the general formula (11) is represented by the general formula (13):

[0046]

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(Wherein X ¹ , i and Z ¹ are the same as above) and can be obtained by reacting a compound having one hydroxyl group at one terminal with a dibasic acid anhydride. Alternatively, general formula (14):

[0048]

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(Wherein X ² , j and Z ² are the same as above) and can be obtained by oxidizing a compound having one hydroxyl group at one terminal.

Compounds having one hydroxyl group at one terminal represented by the general formula (13) or (14) include monovalent hydroxy-containing compounds, monovalent carboxylic acids, monovalent secondary amines, It can be obtained by ring-opening addition of an alkylene oxide to a compound having 1 active carbon atom having one active hydrogen such as a monovalent secondary amide or a monovalent thiol.

Examples of the alkylene oxide include ethylene oxide, propylene oxide, and butylene oxide. These alkylene oxides can be used alone or as a mixture of two or more.

The above-mentioned C 1-20 having one active hydrogen
Examples of the compound include methanol, ethanol, propanol, butanol, amyl alcohol, hexanol,
Alcohols such as cyclohexanol, octyl alcohol, dodecyl alcohol, stearyl alcohol, lauryl alcohol, cetyl alcohol, and benzyl alcohol; phenols such as phenol, cresol and naphthol; 1,3-pentylene glycol monobutyl ether; -Alkylene glycol monoethers such as trimethylpentylene glycol monobutyl ether, 2,2,4-trimethylpentylene glycol monocapryl ether, 2,2,4-trimethylpentylene glycol monolauryl ether, and 1,3-pentylene glycol Monoacetate, 2,2,4-trimethylpentylene glycol monobutyrate, 2,2,4-
Trimethylpentylene glycol monocaprylate,
Alkylene glycol monoesters such as 2,2,4-trimethylpentylene glycol monolaurate;
N-dimethylaminomethanol, N, N-diethylaminomethanol, N, N-dipropylaminomethanol,
N, N-dimethylaminopentanol, N, N-diethylaminopentanol, N, N-dipropylaminopentanol, N, N-dibutylaminopentanol,
N, N-dialkylaminoalkanols such as N-diisobutylaminopentanol, N, N-dimethylaminohexanol and N, N-diethylaminohexanol;
2-hydroxy-1-methylpyrrolidine, 3-hydroxy-1-methylpyrrolidine, 1-ethyl-2-hydroxypyrrolidine, 2-hydroxy-1-methylpiperidine, 3-hydroxy-1-methylpiperidine, 4-hydroxy-1 -Methylpiperidine, 1-ethyl-2-hydroxypiperidine, 2-hydroxypyridine, 3-hydroxypyridine, 4-hydroxypyridine, 2-hydroxymethyl-1-methylpyrrolidine, 3-hydroxymethyl-1-methylpyrrolidine, 1- Ethyl-2-hydroxymethylpyrrolidine, 2-hydroxymethyl-1-methylpiperidine, 3-hydroxymethyl-1-methylpiperidine, 4-hydroxymethyl-1-methylpiperidine, 1-ethyl-2-hydroxymethylpiperidine,
-Hydroxymethylpyridine, 3-hydroxymethylpyridine, 4-hydroxymethylpyridine, 2- (2-hydroxyethyl) -1-methylpyrrolidine, 3- (2-
(Hydroxyethyl) -1-methylpyrrolidine, 1-ethyl-2- (2-hydroxyethyl) pyrrolidine, 2-hydroxyethyl-1-methylpiperidine, 3- (2-hydroxyethyl) -1-methylpiperidine, 4- ( 2-
(Hydroxyethyl) -1-methylpiperidine, 1-ethyl-2- (2-hydroxyethyl) piperidine, 2-
(2-hydroxyethyl) pyridine, 3- (2-hydroxyethyl) pyridine, 4- (2-hydroxyethyl)
Pyridine, 1-hydroxymethylpyrrolidine, 1-hydroxymethylpiperidine, 1-hydroxymethyl-4-
Alcohols having a heterocyclic ring such as methylpiperidine and 1-hydroxymethylmorpholine, dimethylamine, diethylamine, dipropylamine, dibutylamine, dicyclohexylamine, methylethylamine, and ethyl-n-
Secondary amines such as butylamine, N-methylaniline, N-methylbenzylamine, N-methylnaphthylamine, diphenylamine, piperidine, morpholine, pyrrolidine, pyrrole, pyrroline, 1-methylpiperazine,
-Heterocyclic amines such as -ethylpiperazine, 1-butylpiperazine, indole, indoline, etc .; secondary amides such as N-methylacetamide, N-methylacetoacetamide and N-methylacrylamide; N-methyl-N-methylol Acetamide, ethanethiol, butanethiol,
Thiols such as thiophenol, acetic acid, propionic acid,
Saturated aliphatic acids such as butyric acid, caproic acid, capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid, and unsaturated fats such as oleic acid, elaidic acid, linoleic acid, linolenic acid, arachidonic acid, and eleostearic acid Group acids and the like. These can be used alone or in combination of two or more.

The compound having a hydroxyl group at one terminal represented by the general formula (13) or (14) does not need to be an alkylene oxide adduct as described above. Any material having the structure shown can be used.

Examples of such compounds include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monopentyl ether, ethylene glycol monooctyl ether, ethylene glycol monononyl ether, ethylene glycol monolauryl ether, Alkylene glycol monoethers such as ethylene glycol monophenyl ether, propylene glycol monobutyl ether, propylene glycol monooctyl ether, diethylene glycol monomethyl ether, trimethylene glycol monobutyl ether, butylene glycol monobutyl ether, butylene glycol monooctyl ether, and ethylene glycol mono Acetate, d Lenglycol monobutyrate, ethylene glycol monocaprate, ethylene glycol monolaurate, propylene glycol monobutyrate, propylene glycol monocaprate, propylene glycol monolaurate, diethylene glycol monoacetate, diethylene glycol monobutyrate, diethylene glycol monocaprate, Alkylene glycol monoesters such as trimethylene glycol monobutyrate and butylene glycol monocapronate, N, N-dimethylaminoethanol, N, N-diethylaminoethanol, N, N-dipropylaminoethanol, N, N-dibutylamino Ethanol, N- (2
-Ethylhexyl) -N-methylaminoethanol;
N, N-dimethylaminopropanol, N, N-diethylaminopropanol, N, N-dipropylaminopropanol, N, N-dimethylaminobutanol, N, N
N, N-dialkylaminoalkanols such as -diethylaminobutanol, N, N-dipropylaminobutanol, 1- (2-hydroxyethyl) pyrrolidine, 1-
Alcohols having a heterocyclic ring such as (2-hydroxyethyl) piperidine, 1- (2-hydroxyethyl) -4-methylpiperazine and 1- (2-hydroxyethyl) morpholine are exemplified. These can be used alone or in combination of two or more.

Examples of the dibasic anhydride include succinic anhydride, maleic anhydride, itaconic anhydride, cyclohexanedicarboxylic anhydride, phthalic anhydride, dodecenylsuccinic anhydride, tetrahydrophthalic anhydride, phthalic anhydride, and naphthalene. And dicarboxylic anhydrides. These dibasic acid anhydrides can be used alone or in combination of two or more.

The method of oxidizing a compound having one hydroxyl group at one terminal represented by the general formula (14) to obtain a compound having one carboxyl group at one terminal represented by the general formula (12) includes the following. Any of conventionally known methods can be adopted, for example, it can be produced by an oxidation method using nickel peroxide as a catalyst.

In the general formula (1), X ¹ has 2 carbon atoms.
A divalent hydrocarbon group in the range of 1 to 4, i is 1 to 100
Wherein Y is 2 having 2 to 20 carbon atoms.
Z ¹ is a monovalent organic group having no active hydrogen having 1 to 20 carbon atoms and connected to X ¹ by any of oxygen, nitrogen and sulfur atoms. , R ¹ and R ²
Each independently represents a hydrogen atom or a methyl group. In the general formula (2), X ² represents a divalent hydrocarbon group having 2 to 4 carbon atoms, j represents an integer of 1 to 100,
Z ² is any of oxygen, nitrogen or sulfur atom, and has ² to 20 carbon atoms connected to X ² (when j ≠ 0) or β-carbon atom of carbonyl group (when j = 0). Is a monovalent organic group having no active hydrogen in the range of
³ and R ⁴ each independently represent a hydrogen atom or a methyl group;
⁵ represents a monovalent hydrocarbon group having 1 or 2 carbon atoms.
These appropriate structures and appropriate values vary depending on the type of pigment to be used, the specific surface area and particle size of the pigment particles, the properties of the pigment surface treatment agent, the polarity of the dispersion medium, and the like. It is preferable to select an optimal structure and an optimal value. If the value of i or j exceeds the above range, the pigment dispersibility cannot be further improved.

The graft copolymer of the present invention must have a structure represented by the general formula (1) and / or the general formula (2), and the general formula (3) and / or the general formula (4). Must. These contents with respect to the graft copolymer are such that at least 10 mol% of the structural units represented by the general formula (1) and / or the general formula (2) in the graft copolymer.
The corresponding amount, especially the amount corresponding to 10-90 mol%,
The amount of the structural unit represented by the general formula (3) and / or the general formula (4) is preferably at least 10 mol%, more preferably 10 to 90 mol%.
The term "contains at least an amount corresponding to at least 10 mol% of the structural units represented by the general formula (1) and / or the general formula (2)" means that the graft copolymer is derived from an ethylenically unsaturated monomer. Wherein at least 10 mol% of the structural units represented by the general formula (1) and / or the general formula (2) is contained in all the structural units, and the general formula (3) and / or the general formula ( To contain the constituent unit represented by 4) in an amount corresponding to at least 10 mol% means that the graft copolymer is divided into constituent units derived from an ethylenically unsaturated monomer, and the total formula (3) ) And / or at least 10 mol% of the structural unit represented by the general formula (4). If any one or both of them are not contained in an amount corresponding to a predetermined mol%, sufficient pigment dispersibility cannot be obtained. However, the appropriate value varies depending on the type of pigment to be used, the specific surface area and particle size of the pigment particles, the properties of the pigment surface treatment agent, the polarity of the dispersion medium, and the like. It is preferable to choose.

The molecular weight of the graft copolymer of the present invention is preferably in the range of 3,000 to 100,000 in terms of weight average molecular weight. Even if the weight average molecular weight is less than 3,000, the pigment dispersing effect is obtained, but the polymerization reaction becomes difficult, and the effect of improving the emulsification suitability decreases due to the influence of the terminal group due to the polymerization initiator or chain transfer agent which is frequently used. On the other hand, if the weight average molecular weight exceeds 100,000, a sufficient pigment dispersing effect cannot be obtained.

As the pigment to be used in the present invention, general inorganic or organic pigments can be used. As organic pigments, phthalocyanine, azo, anthraquinone, quinacridone, dioxazine, anthrapyrimidine, anthanthrone, indanthrone, flavanthrone,
Examples include perylene-based, thioindigo-based, isoindolinone-based, triphenylmethane-based, and carbon black. As inorganic pigments, extender pigments such as barium sulfate, calcium sulfate, calcium carbonate, magnesium carbonate, aluminum hydroxide, silicon dioxide, titanium dioxide,
Magnetic iron oxide and the like. These organic or inorganic pigments can be used alone or in combination of two or more.

The solvent of the present invention may be any solvent that dissolves the resin component in the pigment dispersion or the resin component used together with the pigment dispersion, and may be appropriately selected from known ones according to the application. .

Further, as the binder resin of the present invention,
Various known binder resins used in the fields of pigment-dispersed resists, paints, printing ink compositions and the like can be used.

In order to obtain the pigment dispersion of the present invention, it is desirable that the graft copolymer is contained as a pigment dispersant in an amount of at least 0.2 part by weight based on 100 parts by weight of the pigment. If the amount of the pigment dispersant is less than this, a sufficient pigment dispersing effect cannot be obtained. On the other hand, even if the pigment dispersant is used in an amount of more than 100 parts by weight based on 100 parts by weight of the pigment, the pigment dispersing effect is not further improved.

However, since the pigment dispersing effect varies depending on the kind of the pigment, the specific surface area and the particle diameter of the pigment particles, the properties of the pigment surface treating agent, the polarity of the dispersion medium, and the like, it is preferable to optimize the individual cases. .

Next, the coating composition using the pigment dispersion of the present invention will be specifically described with reference to a photo-curable pigment-dispersed resist composition for a color filter as an example.

As the pigment dispersant contained in the pigment dispersion, a graft copolymer having 1 to 10 carbon atoms in Z ¹ of the general formula (1) or Z ² of the general formula (2) is preferable.

As the pigment used in the photocurable pigment-dispersed resist composition for a color filter using the pigment dispersion of the present invention, those known in the art can be used. Specific examples include an anthraquinone-based C.I. I. Pigment Red 177, C.I. I. Pigment Red 168 and green pigments such as halogenated phthalocyanine C.I. I. Pigment Green 7, C.I. I. Pigment Green 36 and a blue pigment such as β-type phthalocyanine C.I. I. Pigment Blue 1
5: 3, ε-type phthalocyanine-based C.I. I. Pigment Blue 15: 6, and disazo C.I. I. Pigment Yellow 83, isoindolinone-based C.I. I.
Pigment Yellow 139, and dioxazine-based C.I. I. Pigment Violet 23, chromophtal C.I. I. Pigment Violet 37 or the like can be shown.

For these pigments, the particle diameter needs to be 400 nm or less, which is the lower limit of the wavelength of visible light, in order to increase the light transmittance while maintaining the optical density of the coating film high.
Preferably, it is 200 nm or less, which is そ の of that, and more preferably about 100 nm.

By using the graft copolymer of the present invention, even such a fine pigment can be stably dispersed. In order to obtain a spectrum suitable for each pixel of the three primary colors of R, G, and B, for example, a yellow pigment is used for a red pigment and a green pigment, a purple pigment is used for a blue pigment, or two or more kinds of red pigments are used. And a plurality of pigments can be used in combination.

The pigment dispersion of the present invention containing the above-mentioned extender can be used in a resist used as an overcoat material for a color filter.

When the pigment dispersion of the present invention is used for a photocurable pigment dispersion resist composition for a color filter,
The graft copolymer is used in an amount of 0.2 to 100 parts by weight of the pigment.
100 parts by weight, preferably 1 to 50 parts by weight is contained.

As the solvent used in the photocurable pigment-dispersed resist composition for a color filter using the pigment dispersion of the present invention, a known organic solvent which dissolves a resin component used in this field can be used. be able to.

Specific examples include glycol ethers such as ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, diethylene glycol dimethyl ether, dipropylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and diethylene glycol monoethyl ether. Glycol monoether acetates such as ether acetate, ketones such as cyclohexanone and methyl ethyl ketone, N,
Examples include amides such as N-dimethylacetamide and N-methylpyrrolidone, lactones such as γ-butyrolactone, and acetates such as butyl acetate. These can be used alone or in combination of two or more in consideration of the solubility of the resin component and the coating suitability of the composition.

As the binder resin used in the photocurable pigment-dispersed resist composition for a color filter using the pigment dispersion of the present invention, a known resin may be used in consideration of the compatibility with the organic solvent used. Can be used. As a use of the photocurable pigment-dispersed resist for a color filter, a resin having little coloring is preferable, and examples thereof include an acrylic resin, a styrene resin, a urethane resin, and an epoxy resin.

After photo-curing by radical polymerization, if it is necessary to develop the coating film with an alkali for image formation, a binder resin having an acidic functional group introduced may be used. Acrylic resins in this application include those obtained by copolymerizing a monomer having an ethylenically unsaturated double bond and (meth) acrylic acid, and styrene resins include a copolymer of styrene and maleic anhydride, Copolymers to which various (meth) acrylic acid derivatives are added, or those obtained by reacting an acid anhydride ring of these copolymers with an alcohol to form a half ester are exemplified. Examples of the urethane resin include those in which a carboxyl group has been introduced with dimethylolpropionic acid or the like. If a (meth) acryloyl group is introduced, photocurability can also be imparted. Examples of the epoxy resin include a resin obtained by subjecting an acid component to an epoxy group by epoxy esterification and then reacting an acid anhydride with a generated hydroxyl group. If (meth) acrylic acid is used for the acid component,
Photocurability can be imparted. In addition, heat curing after photocuring by adding an amino resin or the like is also possible.
These may be used alone or in combination of two or more.

As the radical polymerization compound for preparing the photocurable pigment-dispersed resist composition for a color filter using the pigment dispersion of the present invention, polyfunctional (meth) acrylates can be used. Specifically, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, glycerin di (meth) acrylate, trimethylolpropane di (meth) ) Acrylate, trimethylolpropane tri (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate,
Ditrimethylolpropane tri (meth) acrylate,
Ditrimethylolpropane penta (meth) acrylate, pentaerythritol tri (meth) acrylate,
Pentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, di (meth) acrylate of an ester of hydroxypivalic acid and neopentyl glycol, adipic acid and 1,6-hexane Di (meth) acrylates of diol esters,
Di (meth) acrylate of bisphenol A ethylene oxide adduct, di (meth) acrylate of bisphenol A propylene oxide adduct, di (meth) acrylate of tetrabromobisphenol A ethylene oxide adduct, ethylene oxide addition of isocyanuric acid (Meth) acrylates such as di (meth) acrylate, tri (meth) acrylate of ethylene oxide adduct of isocyanuric acid, bisphenol A type epoxy resin, bisphenol F type epoxy resin, novolak type epoxy resin, Polycarboxylic acid glycidyl ester, polyol polyglycidyl ester, alicyclic or aliphatic epoxy resin by modification of rosin or drying oil, amine epoxy resin, triphenolmethane epoxy resin, diphenol Mud carboxymethyl benzene type epoxy polyfunctional epoxy by reaction of the epoxy groups of the resin with (meth) acrylic acid (meth) acrylates. These may be used alone or in combination of two or more. Monofunctional (meth) acrylates can be used in combination with these. In order to increase the curing speed, it is preferable to use acrylates among the above (meth) acrylates.

As a photopolymerization initiator for radical polymerization for preparing a photocurable pigment-dispersed resist composition for a color filter using the pigment dispersion of the present invention, acetophenone-based, benzoin ether-based, benzophenone-based, thioxanthone-based And other known photopolymerization initiators. Specifically, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyldimethylketal, 1-
Hydroxycyclohexylphenyl ketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1-
Acetophenone-based initiators such as (4-morpholinophenyl) -butanone and 1-phenylpropanedione-2- (o-ethoxycarbonyl) oxime; benzoin ether-based initiators such as benzoin and benzoin methyl ether;
Benzophenone, methyl o-benzoylbenzoate, 4-
Phenylbenzophenone, bis (4-dimethylaminophenyl) ketone, 4,4′-dichlorobenzophenone,
Benzophenone initiators such as 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3 ', 4,4'-tetra (t-butylperoxycarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, and isopropylthioxanthone , 2,4-diethylthioxanthone, 2,4-dichlorothioxanthone, 1-chloro-4
Thioxanthone initiators such as propoxythioxanthone, or dibenzoyl, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,2 ′
-Bis (o-chlorophenyl) -4,5,4 ', 5'-
Initiators such as tetraphenyl-1,2-bisimidazole, 10-butyl-2-chloroacridone, 2-ethylanthraquinone, 9,10-phenanthrenequinone, camphorquinone and methylphenylglyoxyester, or titanocene And the like. These can be used alone or in combination of two or more.

Further, a benzophenone-based or thioxanthone-based initiator and a hydrogen abstraction initiator such as a dicarbonyl compound include α-hydrogen such as triethanolamine or methyl 4-dimethylaminobenzoate as a hydrogen donor. Tertiary amines can be used as an accelerator. Further, a dye having a sensitizing effect on long-wavelength light such as xanthene, acridine, oxazine, and cyanine may be added. These can be used alone or in combination of two or more.

Further, stabilizers such as hadroquinone, hydroquinone methyl ether, catechol and picric acid can also be used.

To prepare a photocurable pigment-dispersed resist composition for a color filter using the pigment dispersion of the present invention, various additives such as a lubricant and a surfactant are used in addition to the above-mentioned materials. Can be.

Table 1 shows preferred ranges of the contents of the components in the photocurable pigment-dispersed resist composition for a color filter of the present invention.

[0082]

[Table 1]

Among these components, all or a part of the pigment, the graft copolymer, and the solvent and, if necessary, a part or all of the binder resin are mixed and kneaded using a bead mill or a three-roll mill. Thereby, the pigment dispersion of the present invention can be obtained. The remaining solvent and the binder resin, the radical polymerizable compound, and the photopolymerization initiator are added thereto, and the mixture is further kneaded or sufficiently stirred, and if necessary, is subjected to filter filtration or centrifugal separation. A photo-curable pigment-dispersed resist composition can be obtained.

When the pigment dispersion of the present invention is used in a coating composition other than a pigment-dispersed resist such as ink and paint, various binder resins, solvents and solvents conventionally used in those coating compositions are used. Additives can be used.

[0085]

The present invention will be described below with reference to examples. They do not limit the invention unless it departs from the spirit and scope. "Parts" in the description indicate parts by weight.

[Pigment dispersant] Pigment dispersant 1 A copolymer of styrene and glycidyl methacrylate (contents: 67 mol% and 33 mol%, respectively) was added with an average of 17.2 mol of propylene oxide to butanol, and a hydroxyl group was added to the terminal. Was reacted with succinic anhydride to react a polyether having a carboxyl group at one end to obtain a graft copolymer (pigment dispersant 1). The weight average molecular weight (measured by GPC, hereinafter the same) is 15.0
00.

Pigment Dispersant 2 A copolymer of styrene and glycidyl methacrylate (contents of 67 mol% and 33 mol%, respectively) and a copolymer of vinyl toluene and glycidyl methacrylate (contents of 67 mol Mol%, 33 mol%) to obtain a graft copolymer (pigment dispersant 2) having a weight average molecular weight of 15,000.

Pigment Dispersant 3 A copolymer of styrene and glycidyl methacrylate (contents of 67 mol% and 33 mol%, respectively) and a copolymer of benzyl methacrylate and glycidyl methacrylate (contents of 67 mol%,
33 mol%) and a weight average molecular weight of 17,00
No. 0 graft copolymer (pigment dispersant 3) was obtained.

Pigment Dispersant 4 A pigment-containing polyether having an average of 17.2 mol of propylene oxide added to butanol in Pigment Dispersant 1 and ethylene oxide added to butanol in an average of 2 parts
The graft copolymer having a weight-average molecular weight of 15,000 (pigment dispersant 4) was obtained by substituting 2.7 mol of a polyether having a hydroxyl group at a terminal added thereto.

Pigment Dispersant 5 In the Pigment Dispersant 1, butanol was added with an average of 17.2 mol of propylene oxide on average and a polyether having a hydroxyl group at the terminal was added.
The graft copolymer having a weight average molecular weight of 13,000 (pigment dispersant 5) was obtained by replacing with 3.9 mol of a polyether having a hydroxyl group at a terminal added thereto.

Pigment dispersant 6 A polyether having a hydroxyl group at the terminal obtained by adding 17.2 mol of propylene oxide to butanol in the pigment dispersant 1 on average and a succinic anhydride were reacted with the polyether having a carboxyl group at one terminal. A graft copolymer having a weight-average molecular weight of 14,000 was replaced by a polyether having a carboxyl group at one end obtained by oxidizing a polyether having a hydroxyl group at the end obtained by adding 17.2 mol of ethylene oxide to butanol on average. A pigment dispersant 6) was obtained.

Pigment dispersant 7 In pigment dispersant 1, butanol was added with an average of 17.2 mol of propylene oxide on the butanol side, and a polyether having a hydroxyl group at the terminal was added. Dibutylamine was added with an average of 22.7 mol of propylene oxide on the end, and a hydroxyl group was added on the end. In place of polyether, a graft copolymer having a weight average molecular weight of 15,000 (pigment dispersant 7) was obtained.

[Comparative Pigment Dispersant] Pigment Dispersant 8 The polyether having a hydroxyl group at one end used in Pigment Dispersant 1 was used as Pigment Dispersant 8.

Pigment Dispersant 9 A commercially available sorbitan fatty acid ester compound was used as Pigment Dispersant 9.

[Photocurable Pigment Dispersion Paste for Color Filter] Examples 1 to 9 and Comparative Examples 1 and 2 were described above using pigment dispersants 1 to 7 and comparative pigment dispersants (pigment dispersants 8 and 9). The mixture was kneaded using a bead mill according to the method to prepare a pigment dispersion composition having the composition shown in Table 2. A radical polymerizable compound and a photopolymerization initiator were added thereto, and the mixture was further kneaded. Finally, a photocurable pigment-dispersed resist composition for a color filter having the composition shown in Table 3 was obtained.
Here, propylene glycol monomethyl ether acetate is used as a solvent, and methacrylic acid and benzyl methacrylate are used as a binder resin in a copolymer component. The acid value is 100 mgKOH / g, and the weight average molecular weight is 45,000.
As a radical polymerizable compound, trimethylolpropane triacrylate (TMP-A, manufactured by Kyoeisha Chemical Co., Ltd.),
Methyl-2-morpholino (4-thiomethylphenyl) propan-1-one (manufactured by Ciba-Geigy, IRGACURE)
-907) was used. Table 4 shows the types of pigments used for the R, G, and B color resists and the weight% of the total pigments.

In the preparation of the pigment dispersion, as shown in Table 2, the amount of the solvent was increased or decreased according to the amount of the pigment dispersant used so that the total amount of the composition became 100% by weight.
In the preparation of the pigment-dispersed resist, the total amount of the composition was similarly adjusted to 100% by weight. In Comparative Example 3, the equivalent amount of the pigment dispersant was replaced with propylene glycol monomethyl ether acetate without using the pigment dispersant.

[0097]

[Table 2]

[0098]

[Table 3]

[0099]

[Table 4]

[Evaluation Test] The properties of the pigment dispersion and the photocurable pigment-dispersed resist composition for a color filter and the results of evaluation of the cured film are shown in Table 5.

(1) Viscoelasticity For the obtained pigment dispersion and the photocurable pigment-dispersed resist composition for a color filter, the viscosity immediately after production and the TI
(Thixotropy index)
After storing for 1 month in a dark place maintained at a constant temperature of 0 ° C., the viscosity and TI were measured again, and the changes over time in viscosity and TI were examined. The measurement was performed at 25 ° C. using a rotational viscometer manufactured by Haake. The viscosity is low, TI is close to 1.0, the change with time is small, and the pigment-dispersed resist composition having no problem in spin coating suitability is considered to be excellent in viscoelasticity. Those having a slightly large change with time but capable of being spin-coated were denoted by 2, and those having extremely high viscosity and TI, lacking suitability for spin coating, and having large instability over time were denoted by 1. The case where sedimentation or separation of the pigment was observed was also indicated by 1.

(2) Transmittance The photocurable pigment-dispersed resist composition for each color filter was spin-coated on a glass substrate, heated to 100 ° C. for 2 minutes, and then exposed to 200 mJ / cm ² of ultraviolet light to obtain a thickness. A cured film of 0.9 to 1.1 μm was prepared. With respect to the glass substrate on which the cured film was formed, the transmission spectrum of visible light was measured with reference to the glass substrate. Table 5 shows the transmission range (R: 610 nm, G: 540 nm, B: 4) of each color coating film.
50 nm). The value of the transmittance in Table 5 is a converted value when the thickness of the cured film is 1.0 μm. The higher the transmittance, the better.

[0103]

[Table 5]

By using the graft copolymer of the present invention, the viscoelasticity of a pigment fine dispersion and a photocurable pigment-dispersed resist composition for a color filter using the same are improved, and a cured film having a high transmittance can be obtained. Was done. On the other hand, in the comparative example, the viscoelasticity was poor and the transmittance was low.

[0105]

EFFECT OF THE INVENTION By using the graft copolymer of the present invention, pigment aggregation and structural viscosity of a pigment dispersion and a coating composition using the same are suppressed. Use in the dispersed resist composition also improves performance such as spectral characteristics and storage stability attributed to pigment dispersibility.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location G03F 7/033 G03F 7/033 (72) Inventor Hiroyuki Ishikawa 1-23-37 Edobori, Nishi-ku, Osaka-shi Sakata Inks Inc.

Claims (3)

[Claims] 1. A pigment dispersion containing a pigment, a solvent, a pigment dispersant and, if necessary, a binder resin, the pigment dispersant has a weight average molecular weight of 3,000 to 100,000.
0, in the graft copolymer, an amount corresponding to at least 10 mol% of the structural units represented by the general formula (1) and / or the general formula (2), and the general formula (3 And / or at least 0.2 parts by weight of the graft copolymer containing at least 10 mol% of the structural unit represented by the general formula (4) per 100 parts by weight of the pigment. Pigment dispersion. Embedded image (Wherein, X ¹ represents a divalent hydrocarbon group having 2 to 4 carbon atoms, i represents an integer ranging from 1 to 100, and Y represents a divalent hydrocarbon group having 2 to 20 carbon atoms. Represented by R ¹ , R ²
Each independently represents a hydrogen atom or a methyl group, and Z ¹ is an oxygen, nitrogen or sulfur atom and is connected to X ¹ by a monovalent organic compound having no active hydrogen and having 1 to 20 carbon atoms. Represents a group) (Wherein, X ² represents a divalent hydrocarbon group having 2 to 4 carbon atoms, j represents an integer ranging from 0 to 100, and Z ² represents an oxygen, nitrogen or sulfur atom. ² (where j ≠ 0
) Or the α-carbon atom of the carbonyl group (where j
= 0), a monovalent organic group having no active hydrogen and having 1 to 20 carbon atoms, R ³ and R ⁴ each independently represent a hydrogen atom or a methyl group, and R ⁵ Represents a monovalent hydrocarbon group having 1 or 2 carbon atoms.) (Wherein, R ⁶ is a hydrogen atom or a methyl group, R ⁷ is a hydrogen atom or a halogen atom, R ⁸ and R ⁹ are each independently a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, 5 represents an alkoxy group, an aryloxy group having 6 to 10 carbon atoms, or a halogen atom. (Wherein, R ¹⁰ represents a hydrogen atom or a methyl group, and R ¹¹ represents a single bond or a methylene group) 2. A coating composition comprising the pigment dispersion according to claim 1. 3. A photo-curable pigment-dispersed resist composition for a color filter, comprising the pigment dispersion according to claim 1, a radically polymerizable compound, and a photo-polymerization initiator.