TWI839369B - Dispersant composition, coloring composition, and color filter - Google Patents

Abstract

The subject of the present invention is to provide a dispersant composition which generates less formaldehyde over time. The solution of the present invention is a dispersant composition which contains a polymer having a structural unit represented by the general formula (1). [In the general formula (1), R ¹¹ represents a hydrogen atom or a chain or cyclic hydrocarbon group which may have a substituent. R ¹² represents a chain or cyclic hydrocarbon group which may have a substituent. R ¹¹ and R ¹² may be bonded to each other to form a ring structure. R ¹³ represents a hydrogen atom or a methyl group.]

Description

Dispersant composition, coloring composition, and color filter

The present invention relates to a dispersant composition containing a polymer.

In the past, when manufacturing color filters used in liquid crystal displays, the methods of imparting coloring materials to the substrate include dyeing, printing, inkjet, electroplating, and pigment dispersion. From the perspective of spectral characteristics, durability, pattern shape, and precision, the mainstream of these methods is the pigment dispersion method. In the pigment dispersion method, a coating film composed of a coloring composition such as a mixed pigment, a dispersant, a dispersant (solvent), and a binder resin is formed on a substrate, and then irradiated and cured through a mask of the desired pattern, and alkaline development is performed.

In recent years, in order to obtain good color reproduction and high contrast of color filters, the high concentration of pigments in coloring compositions has been examined. When the pigment is highly concentrated, the relative proportion of the dispersant will decrease, so the dispersant is required to have high dispersibility (for example, refer to patent document 1 (paragraph 0004)). In addition, in alkaline development, alkaline-soluble binder resins play an important role. However, in the case of a pigment dispersion composition with a high pigment concentration, the proportion of the binder resin of the developing component will decrease, thereby reducing the alkaline developing property. Therefore, the dispersant is also required to have the alkaline developing property originally required of the binder resin. As such a dispersant, Patent Document 2 describes the use of an A-B block copolymer as a pigment dispersant, wherein the A-B block copolymer is composed of an A block having a polylactone chain on the side chain and a B block having a tertiary amine group on the side chain (see Patent Document 2 (paragraphs 0023-0045)). 〔Prior Technical Document〕 〔Patent Document〕

Patent document 1: Japanese Patent Publication No. 2009-265515. Patent document 2: Japanese Patent Publication No. 2013-119568.

[Technical Problems to be Solved by the Invention] In order to improve the dispersibility of coloring materials in resin-type dispersants, it is proposed to introduce tertiary amine groups into the side chains (see Patent Document 2). However, resin-type dispersants having tertiary amine groups will generate formaldehyde over time due to the tertiary amine groups. Therefore, if such resin-type dispersants are used in coloring compositions, formaldehyde will be contained in the coloring compositions. In recent years, environmental standards have become more stringent, so if conventional resin-type dispersants are used, the amount of formaldehyde in the coloring composition does not meet environmental standards.

The present invention was developed in view of the above situation, and its purpose is to provide a dispersant composition that generates less formaldehyde over time.

[Technical means for solving technical problems] The dispersant composition of the present invention that can solve the above-mentioned problems contains a polymer having a structural unit represented by the general formula (1).

[Chemical formula 1] [In the general formula (1), R11 represents a hydrogen atom or a chain or cyclic hydrocarbon group which may have a substituent. R12 represents a chain or cyclic hydrocarbon group which may have a substituent. R11 and R12 may be bonded to each other to form a ring structure. R13 represents a hydrogen atom or a methyl group.]

If a polymer having an amine group is used as a dispersant, formaldehyde will be generated over time due to the amine group. The surprising thing about the present invention is that the structural unit having an amine group is changed to a structural unit represented by the general formula (1) without an amine group, thereby suppressing the generation of formaldehyde over time without reducing the dispersibility of the coloring material, thereby reducing the formaldehyde in the dispersant composition.

The present invention includes a coloring composition, which contains the above-mentioned dispersant composition, a coloring material, a binder resin and a dispersant. In addition, the present invention includes a color filter, which has a coloring layer formed by using the above-mentioned coloring composition.

[Effect of the invention] According to the present invention, a dispersant composition with a low amount of formaldehyde generated over time can be obtained.

An example of a preferred embodiment of the present invention is described below. However, the following embodiment is only an example. The present invention is not limited to the following embodiment.

In the present invention, "(meth)acrylic group" is "at least one of acrylic group and methacrylic group". "(Meth)acrylic monomer" is a monomer having "(meth)acryl group" in the molecule. "(Meth)acryl group" is "at least one of acryl group and methacryl group". "Vinyl monomer" is a monomer having a free radical polymerizable carbon-carbon double bond in the molecule. "Structural unit derived from (meth)acrylic monomer" refers to a structural unit in which the free radical polymerizable carbon-carbon double bond of the (meth)acrylic monomer is polymerized to form a carbon-carbon single bond. "Structural unit derived from vinyl monomer" refers to a structural unit in which the free radical polymerizable carbon-carbon double bond of the vinyl monomer is polymerized to form a carbon-carbon single bond.

>Dispersant composition> The dispersant composition of the present invention contains a polymer having a structural unit represented by the general formula (1) as a dispersant component.

If a polymer having an amine group is used as a dispersant, formaldehyde will be generated over time due to the amine group. The surprising thing about the present invention is that the structural unit having an amine group is changed to a structural unit represented by the general formula (1) without an amine group, thereby suppressing the generation of formaldehyde over time without reducing the dispersibility of the coloring material, thereby reducing the formaldehyde in the dispersant composition.

Examples of the polymer having the structural unit represented by the general formula (1) include (meth)acrylic acid polymers.

From the viewpoint of reducing the amount of formaldehyde generated over time, the polymer having the structural unit represented by the general formula (1) preferably does not have an amine group. That is, the vinyl monomers constituting the polymer preferably do not contain a vinyl monomer having an amine group. In the polymer, the content of structural units derived from vinyl monomers having an amine group (including those whose amine groups have been quaternized) is preferably 2% by mass or less, more preferably 1% by mass or less, still more preferably 0.1% by mass or less, and most preferably 0% by mass. In addition, the amine value of the aforementioned polymer is preferably less than 10 mgKOH/g, more preferably less than 5 mgKOH/g, still more preferably less than 3 mgKOH/g, and most preferably 0 mgKOH/g.

The molecular weight of the polymer having the structural unit represented by the general formula (1) is measured by gel permeation chromatography. The weight average molecular weight (Mw) of the above polymer is preferably 3,000 or more, more preferably 4,000 or more, even more preferably 5,000 or more, particularly preferably 6,000 or more, preferably 40,000 or less, more preferably 30,000 or less, even more preferably 25,000 or less, particularly preferably 20,000 or less. If the weight average molecular weight is within the above range, the dispersibility when used as a dispersant is better.

(Block copolymer) From the perspective of dispersibility, the aforementioned polymer is preferably a block copolymer having an A block and a B block, wherein the A block has a structural unit derived from a (meth)acrylic monomer, and the B block has a structural unit represented by the general formula (1). The various constituent components of the aforementioned block copolymer are described below.

(A block) The A block is a polymer block containing structural units derived from (meth) acrylic acid-based monomers. In the A block, the structural units derived from (meth) acrylic acid-based monomers may be only one type or may have two or more types. The structural units derived from (meth) acrylic acid-based monomers can maintain high affinity with the dispersion medium (solvent) and the binder resin blended in the coloring composition.

The content of the structural unit derived from the (meth)acrylic acid group monomer is preferably 80 mass % or more, more preferably 90 mass % or more, further preferably 95 mass % or more, and particularly preferably 100 mass % in 100 mass % of the A block.

Examples of the (meth)acrylic monomer include (meth)acrylates having a chain alkyl group (straight chain alkyl group or branched chain alkyl group), (meth)acrylates having a cyclic alkyl group, (meth)acrylates having a polycyclic structure, (meth)acrylates having an aromatic group, (meth)acrylates having a polyalkylene glycol structural unit, (meth)acrylates having a hydroxyl group, (meth)acrylates having a lactone-modified hydroxyl group, (meth)acrylates having an alkoxy group, (meth)acrylates having an oxygen-containing heterocyclic group, (meth)acrylates having an acidic group, and (meth)acrylic acid. One or a combination of two or more of these monomers may be used.

The aforementioned (meth)acrylate having a linear alkyl group is preferably a (meth)acrylate having a linear alkyl group with a carbon number of 1 to 20, and more preferably a (meth)acrylate having a linear alkyl group with a carbon number of 1 to 10. Examples of the aforementioned (meth)acrylate having a linear alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, n-nonyl (meth)acrylate, decyl (meth)acrylate, n-lauryl (meth)acrylate, and n-stearyl (meth)acrylate.

The aforementioned (meth)acrylate having a branched alkyl group is preferably a (meth)acrylate having a branched alkyl group with a carbon number of 3 to 20, and more preferably a (meth)acrylate having a branched alkyl group with a carbon number of 3 to 10. Examples of the aforementioned (meth)acrylate having a branched alkyl group include isopropyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate, and the like.

The aforementioned (meth)acrylate having a cyclic alkyl group is preferably a (meth)acrylate having a cyclic alkyl group with a carbon number of 6 to 12. Examples of the cyclic alkyl group include cyclic alkyl groups having a monocyclic structure (e.g., cycloalkyl groups). Specific examples of the (meth)acrylate having a monocyclic alkyl group include cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate, and the like.

The aforementioned (meth)acrylate having a polycyclic structure is preferably a (meth)acrylate having a polycyclic structure with a carbon number of 6 to 12. Examples of the polycyclic structure include cyclic alkyl groups having a cross-linked ring structure (e.g., adamantyl, norbornyl, and isobornyl). Specific examples of the (meth)acrylate having a polycyclic structure include isobornyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate.

The aforementioned (meth)acrylate having an aromatic group is preferably an aromatic group having an aromatic group with a carbon number of 6 to 12. The aromatic group may be an aryl group, and may have a chain portion such as an alkylaryl group, an aralkyl group, an aryloxyalkyl group, etc. Specific examples of the (meth)acrylate having an aromatic group include benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, etc.

Examples of the aforementioned (meth)acrylates having a polyalkylene glycol structural unit include (meth)acrylates having a polyethylene glycol structural unit such as polyethylene glycol (degree of polymerization = 2-10) methyl ether (meth)acrylate, polyethylene glycol (degree of polymerization = 2-10) ethyl ether (meth)acrylate, polyethylene glycol (degree of polymerization = 2-10) propyl ether (meth)acrylate, polyethylene glycol (degree of polymerization = 2-10) phenyl ether (meth)acrylate, and the like; and (meth)acrylates having a polypropylene glycol structural unit such as polypropylene glycol (degree of polymerization = 2-10) methyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 2-10) ethyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 2-10) propyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 2-10) phenyl ether (meth)acrylate.

Examples of the (meth)acrylate having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, etc. Among them, more preferred are (meth)acrylates having a hydroxyalkyl group having 1 to 5 carbon atoms.

The aforementioned lactone-modified (meth)acrylate having a hydroxyl group includes a lactone added to the aforementioned (meth)acrylate having a hydroxyl group, preferably a caprolactone added. The amount of caprolactone added is preferably 1 mol to 10 mol, more preferably 1 mol to 5 mol. The aforementioned lactone-modified (meth)acrylate having a hydroxyl group is preferably a caprolactone 1 mol adduct of 2-hydroxyethyl (meth)acrylate, a caprolactone 2 mol adduct of 2-hydroxyethyl (meth)acrylate, a caprolactone 3 mol adduct of 2-hydroxyethyl (meth)acrylate, a caprolactone 4 mol adduct of 2-hydroxyethyl (meth)acrylate, a caprolactone 5 mol adduct of 2-hydroxyethyl (meth)acrylate, a caprolactone 10 mol adduct of 2-hydroxyethyl (meth)acrylate, and the like.

Examples of the (meth)acrylate having an alkoxy group include methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, and the like.

The aforementioned (meth)acrylate having an oxygen-containing heterocyclic group is preferably a (meth)acrylate having a 4- to 6-membered oxygen-containing heterocyclic group. Specific examples of the (meth)acrylate having an oxygen-containing heterocyclic group include glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, (3-ethyloxycyclobutane-3-yl)methyl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, cyclotrihydroxymethylpropane formal (meth)acrylate, 2-[(2-tetrahydropyranyl)oxy]ethyl (meth)acrylate, 1,3-dioxane-(meth)acrylate, and the like.

Examples of the aforementioned acidic group include carboxyl group (-COOH), sulfonic acid group (-SO ₃ H), phosphoric acid group (-OPO ₃ H ₂ ), phosphonic acid group (-PO ₃ H ₂ ), and phosphinate group (-PO ₂ H ₂ ). Examples of the aforementioned (meth)acrylate having an acidic group include (meth)acrylate having a carboxyl group, (meth)acrylate having a phosphoric acid group, and (meth)acrylate having a sulfonic acid group.

Examples of the (meth)acrylate having a carboxyl group include carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxyethyl phthalate, and monomers obtained by reacting a (meth)acrylate having a hydroxyl group with an anhydride such as maleic anhydride, succinic anhydride, or phthalic anhydride. Examples of the (meth)acrylate having a sulfonic acid group include sulfonic acid (meth)acrylate ethyl, and examples of the (meth)acrylate having a phosphoric acid group include 2-(phosphonyloxy)ethyl (meth)acrylate.

The aforementioned A block may have other structural units other than the structural units derived from the (meth)acrylic monomer. The other structural units that the A block may contain are not particularly limited as long as they are formed of vinyl monomers that can copolymerize with both the (meth)acrylic monomer and the vinyl monomers that form the B block described later. The vinyl monomers that can form the other structural units of the A block may be used alone or in combination of two or more.

Specific examples of the vinyl monomers that can form other structural units of the A block include α-olefins, aromatic vinyl monomers, heterocyclic vinyl monomers, carboxylic acid vinyl esters, dienes, etc. These vinyl monomers may have a hydroxyl group or an epoxide group.

Examples of α-olefins include 1-hexene, 1-octene, 1-decene, etc. Examples of aromatic vinyl monomers include styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methoxystyrene, 2-hydroxymethylstyrene, 1-vinylnaphthalene, etc. Examples of heterocyclic vinyl monomers include 2-vinylthiophene, N-methyl-2-vinylpyrrole, 1-vinyl-2-pyrrolidone, 2-vinylpyridine, 4-vinylpyridine, N-phenylmaleimide, N-benzylmaleimide, N-cyclohexylmaleimide, etc. Examples of vinyl carboxylates include vinyl acetate, trimethylvinyl acetate, vinyl benzoate, etc. Examples of dienes include butadiene, isoprene, 4-methyl-1,4-hexadiene, and 7-methyl-1,6-octadiene.

The A block preferably contains a structural unit represented by the general formula (10), that is, preferably contains a structural unit derived from the aforementioned lactone-modified (meth)acrylate having a hydroxyl group. The structural unit represented by the general formula (10) has an ester bond portion in the side chain and a terminal hydroxyl group, so it has a high affinity with the dispersant and the adhesive resin, and can improve the alkaline developing property of the block copolymer.

[Chemical formula 2] [In the general formula (10), n1 represents an integer of 1 to 10. ^R1 represents a hydrogen atom or a methyl group. ^R2 represents an alkylene group having 1 to 10 carbon atoms. ^R3 represents an alkylene group having 1 to 10 carbon atoms.]

In the above formula (10), n1 is preferably an integer of 1 to 7, and more preferably an integer of 1 to 5.

The alkylene group having 1 to 10 carbon atoms represented by R ² may be a straight chain or a branched chain, preferably a straight chain. Specific examples of the alkylene group having 1 to 10 carbon atoms represented by R ² include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene, 1-methylethylene, etc. R ² is preferably an alkylene group having 1 to 5 carbon atoms.

The alkylene group with 1 to 10 carbon atoms represented by R ³ may be a straight chain or a branched chain, preferably a straight chain. Specific examples of the alkylene group with 1 to 10 carbon atoms represented by R ^{3 include methylene, ethylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, heptamethylene, octamethylene, nonamethylene, decamethylene, etc. R 3 is} preferably an alkylene group with 1 to 8 carbon atoms, and more preferably an alkylene group with 3 to 8 carbon atoms.

When the A block contains the structural unit represented by the general formula (10), the content thereof is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, particularly preferably 60% by mass or more, preferably 95% by mass or less, more preferably 90% by mass or less, and still more preferably 85% by mass or less, based on 100% by mass of the A block. By setting the content of the structural unit derived from the lactone-modified (meth)acrylate having a hydroxyl group within the above range, the alkaline developing property of the block copolymer can be improved.

The A block preferably has a structural unit derived from a vinyl monomer having an acidic group (preferably (meth)acrylate or (meth)acrylic acid having an acidic group). Having a structural unit derived from a vinyl monomer having an acidic group can increase the solubility in alkaline developer and improve alkaline developing properties.

When the structural unit derived from a vinyl monomer having an acidic group is contained, the content thereof is preferably 2 mass % or more and preferably 20 mass % or less in 100 mass % of the A block. If the content of the structural unit derived from a vinyl monomer having an acidic group is 2 mass % or more, the dissolution rate when neutralized with an alkali in alkaline development is fast, while if it is 20 mass % or less, the hydrophilicity is not high, and the formation of pixel disorder can be suppressed.

In the aforementioned A block, the content of the structural unit represented by the general formula (1) described below is less than 5% by mass, preferably less than 3% by mass, more preferably less than 1% by mass, and even more preferably less than 0.1% by mass. Most preferably, the structural unit represented by the general formula (1) is not contained. The lower the total content of the structural unit represented by the general formula (1) in the A block, the better the dispersibility of the coloring material.

When the A block contains two or more structural units, the various structural units contained in the A block may be contained in the A block in any form such as random copolymerization or block copolymerization. From the viewpoint of uniformity, it is preferably contained in the form of random copolymerization. For example, the A block can be formed by a copolymer of the structural units constituting the a1 block and the structural units constituting the a2 block.

(B block) B block is a polymer block containing a structural unit represented by the following general formula (1).

(Structural unit represented by general formula (1)) The structural unit represented by general formula (1) may be only one type or may have two or more types. Having the structural unit represented by general formula (1) can improve the adsorption of the coloring material and inhibit the generation of formaldehyde over time.

[Chemical formula 3] [In the general formula (1), R ¹¹ represents a hydrogen atom or a chain or cyclic hydrocarbon group which may have a substituent. R ¹² represents a chain or cyclic hydrocarbon group which may have a substituent. R ¹¹ and R ¹² may be bonded to each other to form a ring structure. R ¹³ represents a hydrogen atom or a methyl group.]

The chain alkyl group represented by R ¹¹ may include a linear alkyl group, a branched alkyl group, and the like. The linear alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 5 carbon atoms. The linear alkyl group may include methyl, ethyl, n-propyl, n-butyl, n-hexyl, n-octyl, n-nonyl, n-decyl, and n-lauryl. The branched alkyl group may preferably have 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms, and even more preferably 3 to 5 carbon atoms. The branched alkyl group may include isopropyl, isobutyl, sec-butyl, t-butyl, 2-ethylhexyl, neopentyl, and isooctyl.

The substituent of the chain alkyl represented by R ¹¹ includes halogen, alkoxy, benzoyl (-COC ₆ H ₅ ), hydroxyl, etc. The chain alkyl represented by R ¹¹ preferably does not have an amino group (including a substituted amino group in which the hydrogen atom of the amino group is substituted by an alkyl group) as a substituent.

The cyclic alkyl group represented by the aforementioned R ¹¹ may include cyclic alkyl groups, aromatic groups, etc., and the cyclic alkyl groups and aromatic groups may have a chain portion. The aforementioned cyclic alkyl group preferably has 4 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, and even more preferably 6 to 10 carbon atoms. The aforementioned cyclic alkyl group may include cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, etc. The aforementioned aromatic group preferably has 6 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, and even more preferably 6 to 8 carbon atoms. The aforementioned aromatic group may include phenyl, tolyl, styrene, mesityl, etc. Examples of the chain portion of the cyclic alkyl group having a chain portion and the chain portion of the aromatic group having a chain portion include an alkylene group having 1 to 12 carbon atoms, preferably an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 1 to 3 carbon atoms.

The substituent of the cyclic alkyl group represented by R ¹¹ may be a halogen group, an alkoxy group, a chain alkyl group, a hydroxyl group, etc. The cyclic alkyl group represented by R ¹¹ preferably does not have an amino group (including a substituted amino group in which the hydrogen atom of the amino group is substituted by an alkyl group) as a substituent.

The chain alkyl group represented by R ¹² may include a linear alkyl group, a branched alkyl group, and the like. The linear alkyl group preferably has a carbon number of 1 to 20, more preferably a carbon number of 1 to 10, and more preferably a carbon number of 1 to 5. The linear alkyl group may include a methyl group, an ethyl group, a n-propyl group, a n-butyl group, a n-hexyl group, a n-octyl group, a n-nonyl group, a n-decyl group, and a n-lauryl group. The branched alkyl group may preferably have a carbon number of 3 to 20, more preferably a carbon number of 3 to 10, and more preferably a carbon number of 3 to 5. The branched alkyl group may include an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a 2-ethylhexyl group, a neopentyl group, an isooctyl group, and the like.

The substituent of the chain alkyl represented by ^R12 may be halogen, alkoxy, _benzoyl ( _-COC6H5 ), hydroxyl, etc. The chain alkyl represented by ^R12 preferably does not have an amino group (including a substituted amino group in which the hydrogen atom of the amino group is substituted by an alkyl group) as a substituent.

The cyclic alkyl group represented by the aforementioned R ¹² may include cyclic alkyl groups, aromatic groups, etc., and the cyclic alkyl groups and aromatic groups may have a chain portion. The aforementioned cyclic alkyl group preferably has 4 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, and even more preferably 6 to 10 carbon atoms. The aforementioned cyclic alkyl group may include cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, etc. The aforementioned aromatic group preferably has 6 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, and even more preferably 6 to 8 carbon atoms. The aforementioned aromatic group may include phenyl, tolyl, styrene, mesityl, etc. Examples of the chain portion of the cyclic alkyl group having a chain portion and the chain portion of the aromatic group having a chain portion include an alkylene group having 1 to 12 carbon atoms, preferably an alkylene group having 1 to 6 carbon atoms, and more preferably an alkylene group having 1 to 3 carbon atoms.

The substituent of the cyclic alkyl group represented by ^R12 may be a halogen group, an alkoxy group, a chain alkyl group, a hydroxyl group, etc. The cyclic alkyl group represented by ^R12 preferably does not have an amino group (including a substituted amino group in which the hydrogen atom of the amino group is substituted by an alkyl group) as a substituent.

The cyclic structure formed by the mutual bonding of R ¹¹ and R ¹² can be, for example, a 5- to 7-membered nitrogen-containing heterocyclic ring or a condensed ring formed by condensing two of the 5- to 7-membered rings. The nitrogen-containing heterocyclic ring is preferably non-aromatic, and more preferably a saturated ring. Specifically, the structures shown in the following formulas (1-1), (1-2), and (1-3) can be cited.

[Chemical formula 4] [In the general formulae (1-1), (1-2), and (1-3), R ¹⁴ represents an alkyl group having 1 to 6 carbon atoms. l represents an integer of 0 to 5. m represents an integer of 0 to 4. n represents an integer of 0 to 4. * represents a bond. When l is 2 to 5, m is 2 to 4, and n is 2 to 4, the plural R ¹⁴ may be the same or different.]

Specific examples of the vinyl monomer forming the structural unit represented by the general formula (1) include dialkyl (meth) acrylamides such as N,N-dimethyl (meth) acrylamide, N,N-diethyl (meth) acrylamide, and N,N-diisopropyl (meth) acrylamide; cyclic amides such as N-(meth) acrylamide morpholine; and alkoxyalkyl acrylamides such as N-methoxymethyl acrylamide and N-ethoxymethyl acrylamide. Among these, N,N-dimethyl (meth) acrylamide, N,N-diethyl (meth) acrylamide, and N-(meth) acrylamide are preferred.

The B block may contain only the structural unit represented by the general formula (1), or may contain other structural units. From the viewpoint of maintaining affinity with the coloring material, the content of the structural unit represented by the general formula (1) in the B block is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more in 100% by mass of the B block. In addition, the B block is preferably substantially free of structural units derived from vinyl monomers having an acidic group. That is, the content of structural units derived from vinyl monomers having an acidic group is preferably 5% by mass or less, and more preferably 2% by mass or less in 100% by mass of the B block.

Specific examples of the vinyl monomers that can form other structural units of the B block include the same ones as exemplified as the specific examples of the vinyl monomers that can form other structural units of the A block.

When the B block contains two or more structural units, the various structural units contained in the B block may be contained in the B block in any form such as random copolymerization or block copolymerization. From the viewpoint of uniformity, it is preferably contained in the form of random copolymerization. For example, the B block may be formed by a copolymer of the structural units constituting the b1 block and the structural units constituting the b2 block.

(Block copolymer) The structure of the block copolymer is preferably a linear block copolymer. In addition, the linear block copolymer may be of any structure (arrangement), but from the viewpoint of the physical properties of the linear block copolymer or the physical properties of the composition, when the A block is represented by A and the B block is represented by B, it is preferably a copolymer having at least one structure selected from the group consisting of (AB) _m type, (AB) _m -A type, and (BA) _m -B type (m is an integer greater than 1, for example, an integer of 1 to 3). From the viewpoint of the operability during processing and the physical properties of the composition, the AB type diblock copolymer is more preferred. By forming an AB type diblock copolymer, the structural unit derived from the (meth)acrylic monomer in the A block and the structural unit represented by the general formula (1) in the B block can be localized, and can effectively act on the coloring material, the dispersant (solvent), and the binder resin (alkali-soluble resin). The aforementioned block copolymer may have other blocks besides the A block and the B block.

The content of the A block is preferably 35% by mass or more, more preferably 40% by mass or more, and more preferably 45% by mass or more, preferably 85% by mass or less, more preferably 80% by mass or less, and more preferably 75% by mass or less in the total 100% by mass of the block copolymer. The content of the B block is preferably 15% by mass or more, more preferably 20% by mass or more, and more preferably 25% by mass or more, and preferably 65% by mass or less, more preferably 60% by mass or less, and more preferably 55% by mass or less in the total 100% by mass of the block copolymer. By adjusting the content of the A block and the B block within the above range, the dispersing performance when used as a dispersant can be further improved.

The mass ratio of the A block to the B block (A block/B block) in the block copolymer is preferably 50/50 or more, more preferably 55/45 or more, and even more preferably 60/40 or more, and preferably 95/5 or less, more preferably 90/10 or less, and even more preferably 80/20 or less. If the mass ratio of the A block to the B block is within the above range, the dispersing performance when used as a dispersant can be further improved.

When the block copolymer contains a structural unit having an acidic group, the content of the structural unit derived from the vinyl monomer having an acidic group in the block copolymer is preferably 1 mass % or more and preferably 10 mass % or less.

In the block copolymer, the content of the structural unit represented by the general formula (1) is preferably 5 mass % or more, more preferably 10 mass % or more, and even more preferably 20 mass % or more, and is preferably 50 mass % or less, more preferably 45 mass % or less, and even more preferably 40 mass % or less.

The molecular weight of the block copolymer is measured by gel permeation chromatography (hereinafter referred to as "GPC"). The weight average molecular weight (Mw) of the block copolymer is preferably 3,000 or more, more preferably 4,000 or more, even more preferably 5,000 or more, particularly preferably 6,000 or more, preferably 40,000 or less, more preferably 30,000 or less, even more preferably 25,000 or less, particularly preferably 20,000 or less. If the weight average molecular weight is within the above range, the dispersing performance when used as a dispersant is better.

The molecular weight distribution (PDI) of the aforementioned block copolymer is preferably 2.5 or less, more preferably 2.0 or less, and even more preferably 1.6 or less. In addition, in the present invention, the molecular weight distribution (PDI) is obtained by (weight average molecular weight (Mw) of the block copolymer)/(number average molecular weight (Mn) of the block copolymer). The smaller the PDI, the narrower the molecular weight distribution width is. It is a copolymer with concentrated molecular weight. When its value is 1.0, the molecular weight distribution width is the narrowest. That is, the lower limit of PDI is 1.0. If the molecular weight distribution (PDI) of the block copolymer exceeds 2.5, it contains small molecular weight and large molecular weight.

From the viewpoint of reducing the amount of formaldehyde generated over time, the block copolymer preferably does not have an amine group. That is, the vinyl monomers constituting the block copolymer preferably do not contain a vinyl monomer having an amine group. In the block copolymer, the content of the structural unit derived from the vinyl monomer having an amine group (including the amine group after quaternization) is preferably 2% by mass or less, more preferably 1% by mass or less, more preferably 0.1% by mass or less, and most preferably 0% by mass. In addition, the amine value of the block copolymer is preferably less than 10 mgKOH/g, more preferably less than 5 mgKOH/g, more preferably less than 3 mgKOH/g, and most preferably 0 mgKOH/g.

When the block copolymer contains a structural unit having an acidic group, the acid value of the block copolymer is preferably 5 mgKOH/g or more and preferably 50 mgKOH/g or less. By making the acid value within this range, the block copolymer can react appropriately with the binder resin (alkali-soluble resin) without damaging the affinity between the block copolymer and the coloring material.

(Method for producing block copolymers) The above-mentioned method for producing block copolymers includes: a method of first producing block A by polymerization of vinyl monomers and then polymerizing monomers of block B on block A; a method of first producing block B and then polymerizing monomers of block A on block B; a method of separately producing block A and block B and then coupling block A with block B, etc.

The polymerization method is not particularly limited, but preferably living radical polymerization. That is, the aforementioned block copolymer is preferably polymerized by living radical polymerization. In the conventional free radical polymerization method, not only the start reaction and the growth reaction will cause the growth end to be inactivated, but the stop reaction and the chain transfer reaction will also cause the growth end to be inactivated, and there is a tendency to easily become a mixture of polymers with various molecular weights and non-uniform compositions. In contrast, the living radical polymerization method not only maintains the simplicity and versatility of the conventional free radical polymerization method, but is also not prone to cause stop reaction or chain transfer, and can grow without inactivating the growth end, so it is easy to produce a polymer with a precisely controlled molecular weight distribution and a uniform composition, which is preferred.

In the living radical polymerization method, there are methods using transition metal catalysts (ATRP method), methods using sulfur-based reversible chain transfer agents (RAFT method), and methods using organic tellurium compounds (TERP method) depending on the method used to stabilize the polymerization growth end. The ATRP method uses an amine complex, so sometimes it cannot be used without protecting the acidic groups of vinyl monomers with acidic groups. The RAFT method is difficult to form a low molecular weight distribution when using multiple monomers, and has disadvantages such as sulfur odor or coloring. Among these methods, the TERP method is preferably used from the perspective of monomer diversity, molecular weight control in the polymer field, uniform composition, or coloring.

The TERP method is a method for polymerizing a radical polymerizable compound (vinyl monomer) using an organic tellurium compound as a chain transfer agent, such as the methods described in International Publication No. 2004/14848, International Publication No. 2004/14962, International Publication No. 2004/072126, and International Publication No. 2004/096870.

Specific polymerization methods of the TERP method include the following (a) to (d). (a) Polymerizing a vinyl monomer using an organic tellurium compound represented by the general formula (3). (b) Polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by the general formula (3) and an azo polymerization initiator. (c) Polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by the general formula (3) and an organic ditelluride compound represented by the general formula (4). (d) Polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by the general formula (3), an azo polymerization initiator, and an organic ditelluride compound represented by the general formula (4).

[Chemical formula 5] [In general formula (3), R ³¹ represents an alkyl group having 1 to 8 carbon atoms, an aryl group or an aromatic heterocyclic group. R ³² and R ³³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. R ³⁴ represents an alkyl group having 1 to 8 carbon atoms, an aryl group, a substituted aryl group, an aromatic heterocyclic group, an alkoxy group, an acyl group, an amide group, an oxycarbonyl group, a cyano group, an allyl group or a propargyl group. In general formula (4), R ³¹ represents an alkyl group having 1 to 8 carbon atoms, an aryl group or an aromatic heterocyclic group.]

The group represented by R ³¹ is an alkyl group, an aryl group or an aromatic heterocyclic group having 1 to 8 carbon atoms, and specifically, the following are provided. Examples of the alkyl group having 1 to 8 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl and other straight or branched chain alkyl groups, or cyclohexyl and other cyclic alkyl groups. Preferably, it is a straight or branched chain alkyl group having 1 to 4 carbon atoms, and more preferably, it is methyl or ethyl. Examples of the aryl group include phenyl and naphthyl. Examples of the aromatic heterocyclic group include pyridyl, furyl, thienyl and the like.

The groups represented by R ³² and R ³³ are independently hydrogen atoms or alkyl groups having 1 to 8 carbon atoms, and the specific examples of each group are as follows. Examples of alkyl groups having 1 to 8 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, and other linear or branched alkyl groups, or cyclohexyl, and other cyclic alkyl groups. Preferably, it is a linear or branched alkyl group having 1 to 4 carbon atoms, and more preferably, it is a methyl or ethyl group.

The group represented by R ³⁴ is an alkyl group having 1 to 8 carbon atoms, an aryl group, a substituted aryl group, an aromatic heterocyclic group, an alkoxy group, an acyl group, an amide group, an oxycarbonyl group, a cyano group, an allyl group or a propargyl group, and specifically, the following. Examples of the alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, and a cyclohexyl group. Preferably, it is a straight or branched alkyl group having 1 to 4 carbon atoms, and more preferably, it is a methyl group or an ethyl group. Examples of the aryl group include a phenyl group, a naphthyl group, and the like. Preferably, it is a phenyl group. Examples of the substituted aryl group include a phenyl group having a substituent, a naphthyl group having a substituent, and the like. Examples of the substituents of the aforementioned aryl group having a substituent include a halogen atom, a hydroxyl group, an alkoxy group, an amino group, a nitro group, a cyano group, a carbonyl group represented by -COR ³⁴¹ (R ³⁴¹ is an alkyl group having 1 to 8 carbon atoms, an aryl group, an alkoxy group having 1 to 8 carbon atoms, or an aryloxy group), a sulfonyl group, a trifluoromethyl group, and the like. In addition, the substituents may substitute one or two of the substituents. Examples of the aromatic heterocyclic group include a pyridyl group, a furyl group, a thienyl group, and the like. The alkoxy group is preferably a group in which an alkyl group having 1 to 8 carbon atoms is bonded to an oxygen atom, and examples thereof include a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group, a n-butoxy group, a sec-butoxy group, a tert-butoxy group, a pentyl group, a hexyl group, a heptyl group, and an octyl group. Examples of the acyl group include an acetyl group, a propionyl group, and a benzoyl group. Examples of the amide group include -CONR ³⁴²¹ R ³⁴²² (R ³⁴²¹ and R ³⁴²² are independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group). The oxycarbonyl group is preferably a group represented by -COOR ³⁴³¹ (R ³⁴³¹ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, or an aryl group), and examples thereof include carboxyl, methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, n-butoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl, n-pentyloxycarbonyl, and phenoxycarbonyl. Preferred oxycarbonyl groups include methoxycarbonyl and ethoxycarbonyl. Examples of allyl groups include -CR ³⁴⁴¹ R ³⁴⁴² -CR ³⁴⁴³ =CR ³⁴⁴⁴ R ³⁴⁴⁵ (R ³⁴⁴¹ and R ³⁴⁴² are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ³⁴⁴³ , R ³⁴⁴⁴ and R ³⁴⁴⁵ are each independently a hydrogen atom, an alkyl group having 1 to 8 carbon atoms or an aryl group, and each substituent may be linked in a ring structure). Examples of propargyl groups include -CR ³⁴⁵¹ R ³⁴⁵² -C≡CR ³⁴⁵³ (R ³⁴⁵¹ and R ³⁴⁵² are each a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³⁴⁵³ is a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an aryl group or a silicon group).

Specific examples of the organotellurium compound represented by the general formula (3) include (methyltellurylmethyl)benzene, (methyltellurylmethyl)naphthalene, ethyl-2-methyl-2-methyltelluryl-propionate, ethyl-2-methyl-2-n-butyltelluryl-propionate, (2-trimethylsilyloxyethyl)-2-methyl-2-methyltelluryl-propionate, (2-hydroxyethyl)-2-methyl-2-methyltelluryl-propionate, or (3-trimethylsilylpropargyl)-2-methyl-2-methyltelluryl-propionate, and all the organotellurium compounds described in International Publication Nos. 2004/14848, 2004/14962, 2004/072126, and 2004/096870.

Specific examples of the organic ditelluride compound represented by the general formula (4) include dimethyl ditelluride, diethyl ditelluride, di-n-propyl ditelluride, diisopropyl ditelluride, dicyclopropyl ditelluride, di-n-butyl ditelluride, di-sec-butyl ditelluride, di-t-butyl ditelluride, dicyclobutyl ditelluride, diphenyl ditelluride, bis-(p-methoxyphenyl) ditelluride, bis-(p-aminophenyl) ditelluride, bis-(p-nitrophenyl) ditelluride, bis-(p-cyanophenyl) ditelluride, bis-(p-sulfonylphenyl) ditelluride, dinaphthyl ditelluride, and dipyridyl ditelluride.

The azo-based polymerization initiator may be any azo-based polymerization initiator used in general free radical polymerization, without particular limitation. Examples thereof include 2,2'-azobis(isobutyronitrile) (AIBN), 2,2'-azobis(2-methylbutyronitrile) (AMBN), 2,2'-azobis(2,4-dimethylvaleronitrile) (ADVN), 1,1'-azobis(1-cyclohexanecarbonitrile) (ACHN), dimethyl-2,2'-azobisisobutyrate (MAIB), 4,4'-azobis(4-cyanovaleric acid) (ACVA), 1,1'-azobis(1-acetyloxy-1-phenylethane), 2,2'-azobis(2-methylbutylamide), 2,2'- Azobis(4-methoxy-2,4-dimethylvaleronitrile) (V-70), 2,2’-azobis(2-methylformamidinopropane) dihydrochloride, 2,2’-azobis[2-(2-imidazolin-2-yl)propane], 2,2’-azobis[2-methyl-N-(2-hydroxyethyl)propionamide], 2,2’-azobis(2,4,4-trimethylpentane), 2-cyano-2-propylazoformamide, 2,2’-azobis(N-butyl-2-methylpropionamide), or 2,2’-azobis(N-cyclohexyl-2-methylpropionamide), etc.

The polymerization step is to mix the vinyl monomer and the organic telluride compound of the general formula (3) in a container substituted with an inert gas, and further mix an azo polymerization initiator and/or an organic ditelluride compound of the general formula (4) for the purpose of promoting the reaction, controlling the molecular weight and molecular weight distribution, etc., depending on the type of the vinyl monomer. At this time, the inert gas may include nitrogen, argon, helium, etc. Argon and nitrogen are preferred.

In the above (a), (b), (c) and (d), the amount of the vinyl monomer used can be appropriately adjusted according to the physical properties of the target copolymer. Preferably, the amount of the vinyl monomer is 5 mol to 10,000 mol relative to 1 mol of the organotellurium compound of the general formula (3).

When the organotellurium compound of the general formula (3) and an azo polymerization initiator are used together in the above step (b), the amount of the azo polymerization initiator is preferably 0.01 mol to 10 mol relative to 1 mol of the organotellurium compound of the general formula (3).

When the organic tellurium compound of the general formula (3) and the organic ditelluride compound of the general formula (4) are used together in the above-mentioned step (c), the organic ditelluride compound of the general formula (4) is preferably used in an amount of 0.01 mol to 100 mol relative to 1 mol of the organic tellurium compound of the general formula (3).

When the organic tellurium compound of the general formula (3) and the organic ditelluride compound of the general formula (4) are used together with an azo polymerization initiator in the aforementioned step (d), the organic ditelluride compound of the general formula (4) is preferably in an amount of 0.01 mol to 100 mol relative to 1 mol of the organic tellurium compound of the general formula (3), and the azo polymerization initiator is preferably in an amount of 0.01 mol to 10 mol relative to 1 mol of the organic tellurium compound of the general formula (3).

The polymerization reaction can be carried out even without a solvent, and the polymerization reaction can be carried out by stirring the above-mentioned mixture with an aprotic solvent or a protic solvent generally used in free radical polymerization. Examples of aprotic solvents that can be used include anisole, benzene, toluene, N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetone, 2-butanone (methyl ethyl ketone), dioxane, propylene glycol monomethyl ether acetate, chloroform, carbon tetrachloride, tetrahydrofuran (THF), ethyl acetate, or trifluoromethylbenzene. Examples of protic solvents include water, methanol, ethanol, isopropanol, n-butanol, ethyl cellulose, butyl cellulose, 1-methoxy-2-propanol, hexafluoroisopropanol, or diacetone alcohol.

The amount of the solvent used may be appropriately adjusted. For example, it is preferably 0.01 ml or more, more preferably 0.05 ml or more, and even more preferably 0.1 ml or more, and is preferably 50 ml or less, more preferably 10 ml or less, and even more preferably 1 ml or less, relative to 1 g of the vinyl monomer.

The reaction temperature and reaction time can be appropriately adjusted according to the molecular weight or molecular weight distribution of the obtained copolymer, usually stirring at 0℃~150℃ for 1 minute to 100 hours. The TERP method can obtain high yield and precise molecular weight distribution even at low polymerization temperature and short polymerization time. At this time, the pressure is usually carried out at normal pressure, but it can be pressurized or reduced pressure.

After the polymerization reaction is completed, the target copolymer can be isolated by removing the used solvent and residual vinyl monomers from the obtained reaction mixture by general separation and purification means.

The copolymer obtained by the polymerization reaction has a growth end in the form of -TeR ³¹ (wherein R ³¹ is the same as above) derived from a tellurium compound. After the polymerization reaction is completed, it will be deactivated when handled in air, but tellurium atoms will remain. A copolymer with tellurium atoms remaining at the end will be colored or have poor thermal stability, so it is better to remove the tellurium atoms.

The methods for removing tellurium atoms include: Free radical reduction method using tributyltin or thiol compounds; Adsorption method using activated carbon, silica gel, activated alumina, activated clay, molecular sieve and polymer adsorbent; Methods for adsorbing metals using ion exchange resins; Adding peroxides such as hydrogen peroxide or benzoyl peroxide, or blowing air or oxygen into the system, thereby oxidizing and decomposing the tellurium atoms at the ends of the copolymer, combined with water washing or appropriate solvents to remove residual tellurium compounds by liquid-liquid extraction or solid-liquid extraction; Purification method in solution state such as superfiltration to extract and remove only those below a specific molecular weight; Also, these methods can be used in combination.

The other end of the copolymer obtained by the polymerization reaction (the end opposite to the growth end) is in the form of -CR ³² R ³³ R ³⁴ (wherein R ³² , R ³³ and R ³⁴ are the same as R ³² , R ³³ and R ³⁴ in formula (3)) derived from the tellurium compound.

(Polymerization product) In the aforementioned dispersant composition, the dispersant component may use a polymerization product containing the aforementioned block copolymer. The aforementioned polymerization product refers to a product obtained when a polymerization operation is performed to obtain the aforementioned block copolymer. The aforementioned polymerization product contains the desired block copolymer and polymer impurities that are by-products when synthesizing the block copolymer.

The aforementioned polymer impurities refer to other polymers that are inevitable by-products when synthesizing the desired block copolymer. For example, when synthesizing an A-B diblock copolymer, the by-product polymer impurities include random polymers with the same composition as the A block and random polymers with the same composition as the B block. In addition, polymer impurities are polymers that are by-products when synthesizing the desired block copolymer, and do not include polymers that are added separately.

In the above-mentioned polymer product, the content of the above-mentioned block copolymer is preferably 50 mass % or more in 100 mass % of the polymer product. If the content of the block copolymer in the polymer product is 50 mass % or more, the dispersion performance can be improved when the polymer product is used as a dispersant.

(Dispersant) The aforementioned dispersant composition may contain a dispersant. The aforementioned dispersant may be appropriately selected and used as long as it can disperse or dissolve the block copolymer, does not react with the components, and has appropriate volatility. For example, conventionally known organic solvents can be used, such as glycol monoalkyl ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-butyl ether, propylene glycol t-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, methoxymethylpentanol, methoxypropanol, propylene glycol monoethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monomethyl ether, 3-methyl-3-methoxybutanol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tripropylene glycol methyl ether; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dipropyl ether, diethylene glycol dibutyl ... Propylene glycol dimethyl ether and other glycol dialkyl ethers; ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-butyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monopropyl ether acetate, propylene glycol monobutyl ether acetate, methoxybutyl acetate, 3-methoxybutyl acetate, methoxypentyl acetate, diethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol mono-n-butyl ether acetate, dipropylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether acetate, triethylene glycol monoethyl ether acetate, 3-methyl-3-methoxybutyl acetate and other glycol alkyl ether acetates; ethylene glycol diacetate, 1,3-butanediol diacetate, 1,6-hexanediol diacetate and other glycol diacetates Acetic esters; alkyl acetates such as cyclohexanol acetate; ethers such as amyl ether, propyl ether, diethyl ether, dipropyl ether, diisopropyl ether, butyl ether, diamyl ether, ethylisobutyl ether, dihexyl ether; acetone, methyl ethyl ketone, methyl amyl ketone, methylisopropyl ketone, methylisobutyl ketone, diisopropyl ketone, diisobutyl ketone, methylisobutyl ketone, cyclohexanone, ethylamyl ketone, methylisobutyl ketone, methylhexanone , methyl nonanone, methoxymethyl pentanone and other ketones; ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, propylene glycol, butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, glycerol, benzyl alcohol and other monohydric or polyhydric alcohols; n-pentane, n-octane, isobutylene, n-hexane, hexene, isoprene, dipentene, dodecane and other aliphatic hydrocarbons; cyclohexane, methylcyclohexane, methylcyclohexane alicyclic hydrocarbons such as hexene and dicyclohexane; aromatic hydrocarbons such as benzene, toluene, xylene, and cumene; amyl formate, ethyl formate, ethyl acetate, butyl acetate, propyl acetate, amyl acetate, methyl isobutyrate, ethylene glycol acetate, ethyl propionate, propyl propionate, butyl butyrate, isobutyl butyrate, methyl isobutyrate, ethyl octanoate, butyl stearate, ethyl benzoate, 3-ethoxypropyl Chain or cyclic esters such as methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, methyl 3-methoxypropionate, ethyl 3-methoxypropionate, propyl 3-methoxypropionate, butyl 3-methoxypropionate, and γ-butyrolactone; alkoxycarboxylic acids such as 3-methoxypropionic acid and 3-ethoxypropionic acid; halogenated hydrocarbons such as butyl chloride and pentyl chloride; ether ketones such as methoxymethyl pentanone; nitriles such as acetonitrile and benzonitrile, etc.

The content of the dispersant in the above-mentioned dispersant composition can be adjusted appropriately without special limitation. The upper limit of the dispersant content in the dispersant composition is usually 99% by mass. In addition, considering the viscosity suitable for producing the coloring composition described later, the lower limit of the dispersant content in the dispersant composition is usually 10% by mass, preferably 30% by mass.

>Coloring composition> The coloring composition of the present invention contains the aforementioned dispersant composition, a coloring material, a binder resin and a dispersant.

(Coloring material) The type of the aforementioned coloring material can be appropriately selected according to its use, and examples thereof include pigments and dyes. From the viewpoint of light resistance and heat resistance, the aforementioned coloring composition preferably contains a pigment as a coloring material. The pigment may be either an organic pigment or an inorganic pigment, but an organic pigment having an organic compound as a main component is particularly preferred. Examples of the pigment include various color pigments such as red pigment, yellow pigment, orange pigment, blue pigment, green pigment, and purple pigment. Examples of pigment structures include monoazo pigments, diazo pigments, condensed diazo pigments and other azo pigments, diketopyrrolopyrrole pigments, phthalocyanine pigments, isoindolone pigments, isoindoline pigments, quinacridone pigments, indigo pigments, thioindigo pigments, quinoline yellow pigments, bisoxizone pigments, anthraquinone pigments, perylene pigments, peroxycyclic pigments and other polycyclic pigments. The coloring composition may contain only one type of pigment or a plurality of types of pigments.

Specific examples of pigments include C.I. Pigment Red 7, 9, 14, 41, 48:1, 48:2, 48:3, 48:4, 81:1, 81:2, 81:3, 122, 123, 146, 149, 166, 168, 177, 178, 179, 187, 200, 202, 208, 210, 215, 224, 254, 255, 264, 269 and other red pigments; C.I. Pigment Yellow 1, 3, 5, 6, 14, 55, 60, 61, 62, 63, 65, 73, 74, 77, 81, 93, 97, 98, 104, 108, 110, 138, 139, 147, 150, 151, 154, 155, 166, 167, 168, 170, 180, 185, 188, 193, 194, 213 and other yellow pigments; C.I. Pigment Orange 36, 38, 43 and other orange pigments; C.I. Pigment Blue 15, 15:2, 15:3, 15:4, 15:6, 16, 22, 60 and other blue pigments; C.I. Pigment Green Green pigments such as 7, 36, 58, 59, 62, 63, aluminum phthalocyanine, polyhalogenated aluminum phthalocyanine, aluminum phthalocyanine hydroxide, diphenoxyphosphinoaluminum phthalocyanine, diphenylphosphinoaluminum phthalocyanine, polyhalogenated diphenoxyphosphinoaluminum phthalocyanine, polyhalogenated diphenylphosphinoaluminum phthalocyanine, etc.; purple pigments such as C.I. Pigment Violet 23, 32, 50, etc. Preferred pigments include C.I. Pigment Red 254, C.I. Pigment Red 255, C.I. Pigment Red 264, C.I. Pigment Blue 15, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:6, C.I. Pigment Blue 16, C.I. Pigment Green 7, C.I. Pigment Green 36, C.I. Pigment Green 58, C.I. Pigment Green 59, etc.

When the coloring composition of the present invention is used to form a light-shielding material such as a black matrix of a color filter, a black pigment can be used. The black pigment can be used alone, or it can be mixed with the aforementioned red pigment, the aforementioned green pigment, the aforementioned blue pigment, etc. Black pigments include carbon black, acetylene black, lamp black, bone black, graphite, iron black, titanium black, etc. Among them, carbon black and titanium black are preferred from the viewpoint of light-shielding rate and image characteristics.

The average particle size of the coloring material can be appropriately selected according to its application and is not particularly limited. From the perspective of high transparency and high contrast, the coloring composition preferably contains a coloring material with an average particle size of 10nm to 150nm.

The aforementioned coloring material may contain a pigment derivative as a dispersing aid. In order to ionically bond and adsorb with the amide group in the polymer contained in the dispersant composition, the aforementioned pigment derivative is preferably an acidic pigment derivative containing an acidic group. The pigment derivative is one in which an acidic functional group is introduced into the pigment skeleton. The pigment skeleton is preferably a skeleton that is the same as or similar to the coloring material constituting the coloring composition, or a skeleton that is the same as or similar to the compound of the pigment raw material. Specific examples of the pigment skeleton include an azo pigment skeleton, a phthalocyanine pigment skeleton, an anthraquinone pigment skeleton, a triazine pigment skeleton, an acridine pigment skeleton, a perylene pigment skeleton, etc. The acidic group introduced into the pigment skeleton is preferably a carboxyl group, a phosphoric acid group, or a sulfonic acid group. In addition, in terms of the ease of synthesis and the strength of the acidity, a sulfonic acid group is preferred. In addition, the acidic group may be directly bonded to the pigment skeleton, or may be bonded to the pigment skeleton via a hydrocarbon group such as an alkyl or aryl group; an ester, an ether, a sulfonamide, or a carbamate bond. The amount of the pigment derivative used is not particularly limited, and is preferably 4 to 17 parts by weight relative to 100 parts by weight of the coloring material.

From the perspective of brightness, the upper limit of the coloring material content in the coloring composition is generally 80% by mass, preferably 70% by mass, and more preferably 60% by mass of the total solid content of the coloring composition. In addition, the lower limit of the coloring material content in the coloring composition is generally 10% by mass, preferably 20% by mass, and more preferably 30% by mass of the total solid content of the coloring composition. Here, the solid component refers to the components other than the dispersion medium described later.

The content of the dispersant component (block copolymer and polymer product) relative to the coloring material in the coloring composition is preferably 5 to 200 parts by mass, more preferably 10 to 100 parts by mass, and even more preferably 10 to 80 parts by mass relative to 100 parts by mass of the coloring material.

(Binder resin) The aforementioned coloring composition contains a binder resin (but excluding the aforementioned polymer having a structural unit represented by general formula (1)). This can improve the alkaline developing property of the coloring composition or the bonding property with the substrate. Such a binder resin is not particularly limited, and preferably a resin having an acidic group such as a carboxyl group or a phenolic hydroxyl group.

The adhesive resin is preferably a random copolymer containing structural units derived from a carboxyl-containing vinyl monomer and structural units derived from a (meth)acrylate. The carboxyl-containing vinyl monomer is preferably (meth)acrylic acid. Examples of the (meth)acrylate include methyl (meth)acrylate, butyl (meth)acrylate, and benzyl (meth)acrylate.

In the aforementioned adhesive resin, the total content of structural units derived from carboxyl-containing vinyl monomers and structural units derived from (meth)acrylate is preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. In addition, in the aforementioned adhesive resin, the content of the structure derived from carboxyl-containing vinyl monomers is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, and preferably 90% by mass or less, and even more preferably 70% by mass or less.

Among these, random copolymers of carboxyl-containing vinyl monomers and (meth)acrylates are preferred. Specific examples of such copolymers include random copolymers of (meth)acrylic acid and butyl (meth)acrylate, random copolymers of (meth)acrylic acid and benzyl (meth)acrylate, and random copolymers of (meth)acrylic acid, butyl (meth)acrylate, and benzyl (meth)acrylate. From the perspective of the affinity between the adhesive resin and the coloring material, the adhesive resin is particularly preferably a random copolymer of (meth)acrylic acid and benzyl (meth)acrylate.

In the copolymer of the carboxyl group-containing vinyl monomer and (meth)acrylate, the content of (meth)acrylate in the total monomer components is usually 5 mass% to 90 mass%, preferably 10 mass% to 70 mass%, and more preferably 20 mass% to 70 mass%.

The aforementioned adhesive resin may have a carbon-carbon double bond capable of free radical polymerization in the side chain. By having a double bond in the side chain, the light curing property of the coloring composition of the present invention is improved, so the resolution and adhesion can be further improved. The method of introducing a carbon-carbon double bond capable of free radical polymerization in the side chain can be, for example, a method of reacting compounds such as (meth) acrylate glycidyl, (meth) acrylate 3,4-epoxyhexylmethyl, o-(or o- or o-) vinylbenzyl glycidyl ether with the acidic group of the aforementioned adhesive resin.

The Mw of the binder resin is preferably 3,000 to 100,000, more preferably 5,000 to 50,000, and even more preferably 5,000 to 20,000. If the Mw of the binder resin is 3,000 or more, the heat resistance and film strength of the coloring layer formed by the coloring composition are good, and if the Mw is 100,000 or less, the alkaline developability of the coating film is better.

The acid value of the binder resin is preferably 20 mgKOH/g to 170 mgKOH/g, more preferably 50 mgKOH/g to 150 mgKOH/g, and even more preferably 90 mgKOH/g to 150 mgKOH/g. If the acid value of the binder resin is 20 mgKOH/g or more, the alkaline developing property of the coloring composition when forming a coloring layer is better, and if it is 170 mgKOH/g or less, the heat resistance is good.

The binder resin contained in the coloring composition may be only one type or multiple types. In the coloring composition, the binder resin content is preferably 3 to 200 parts by mass, more preferably 10 to 100 parts by mass, and even more preferably 20 to 80 parts by mass relative to 100 parts by mass of the coloring material.

(Crosslinking agent) The aforementioned coloring composition may contain a crosslinking agent as needed. The crosslinking agent is a compound having two or more polymerizable groups. Examples of polymerizable groups include ethylenic unsaturated groups, ethylene oxide groups, cyclobutylene oxide groups, N-alkoxymethylamino groups, etc. The aforementioned crosslinking agent is preferably a compound having two or more (meth)acryloyl groups, or a compound having two or more N-alkoxymethylamino groups.

Specific examples of the aforementioned compound having two or more (meth)acryloyl groups include multifunctional (meth)acrylates obtained by reacting an aliphatic polyhydroxy compound with (meth)acrylic acid, caprolactone-modified multifunctional (meth)acrylates, alkylene oxide-modified multifunctional (meth)acrylates, multifunctional urethane (meth)acrylates obtained by reacting a hydroxyl (meth)acrylate with a multifunctional isocyanate, and multifunctional (meth)acrylates having a carboxyl group obtained by reacting a hydroxyl (meth)acrylate with an acid anhydride.

Examples of the aforementioned aliphatic polyhydroxy compounds include divalent aliphatic polyhydroxy compounds such as ethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol; and trivalent or higher aliphatic polyhydroxy compounds such as glycerol, trihydroxymethylpropane, pentaerythritol, and dipentaerythritol. Examples of the aforementioned (meth)acrylates having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, trihydroxymethylpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and glycerol di(meth)acrylate. Examples of the aforementioned multifunctional isocyanates include toluene diisocyanate, hexamethylene diisocyanate, diphenylmethylene diisocyanate, and isophorone diisocyanate. Examples of the acid anhydride include dibasic acid anhydrides such as succinic anhydride, maleic anhydride, glutaric anhydride, itaconic anhydride, phthalic anhydride, hexahydrophthalic anhydride, and the like; and tetrabasic acid dianhydrides such as pyrophyllite anhydride, biphenyltetracarboxylic dianhydride, and diphenyl ketonetetracarboxylic dianhydride.

In the aforementioned coloring composition, the crosslinking agent content is preferably 10 to 1,000 parts by mass, more preferably 20 to 500 parts by mass, relative to 100 parts by mass of the coloring material. If the crosslinking agent content is too low, there is a risk that sufficient curability cannot be obtained. On the other hand, if the crosslinking agent content is too high, the coloring composition of the present invention has a reduced alkaline developing property, and is prone to staining and film residue on the unexposed substrate or the light-shielding layer.

(Photopolymerization initiator) The aforementioned coloring composition may contain a photopolymerization initiator as needed. This can impart radiation sensitivity to the coloring composition. The aforementioned photopolymerization initiator is a compound that generates active species that can initiate polymerization of the crosslinking agent by exposure to radiation such as visible light, ultraviolet light, far infrared light, electron beam, X-ray, etc.

Examples of the photopolymerization initiator include thioxanthone compounds, acetophenone compounds, diimidazole compounds, triazine compounds, O-acyl oxime compounds, onium salt compounds, benzoin compounds, diphenyl ketone compounds, α-diketone compounds, polynuclear quinone compounds, diazo compounds, imidosulfonate compounds, and aminoketone compounds. The photopolymerization initiator may be used alone or in combination of two or more.

In the coloring composition of the present invention, the amount of the photopolymerization initiator is preferably 0.01 to 120 parts by mass, more preferably 1 to 100 parts by mass, relative to 100 parts by mass of the crosslinking agent. If the amount of the photopolymerization initiator is too small, there is a risk of insufficient exposure and curing, while if it is too large, the formed coloring layer tends to fall off from the substrate during development.

(Dispersant) The aforementioned coloring composition may contain a dispersant. The aforementioned dispersant may be appropriately selected and used as long as it can disperse or dissolve other components constituting the coloring composition, does not react with such components, and has appropriate volatility. For example, conventionally known organic solvents may be used, such as the organic solvents (dispersants) that can be used in the aforementioned dispersant composition. From the perspective of the dispersibility of the pigment, the solubility of the dispersant, and the coating properties of the pigment dispersion composition, the organic solvent is preferably a glycol alkyl ether acetate, a monohydric or polyhydric alcohol. The solvent contained in the pigment dispersion composition may be only one type or a plurality of types.

When forming the pixels of the color filter by photolithography, the boiling point of the above-mentioned dispersion medium (under the condition of pressure 1013.25hPa. The same applies to the boiling point below) is preferably 100℃~200℃. In view of the good balance of coating properties, surface tension, etc., and the higher solubility of the components in the coloring composition, the above-mentioned dispersion medium is preferably glycol alkyl ether acetate. In addition, it is better to use a dispersion medium with a boiling point of 150℃ or more. By using a dispersion medium with a high boiling point, it is possible to suppress the mutual relationship of the coloring composition due to rapid drying of the coloring composition. In addition, the dispersion medium with a boiling point of 150℃ or more can be glycol alkyl ether acetate. The content ratio of the dispersion medium with a boiling point of 150℃ or more is preferably 3~50 mass% in the total dispersion medium 100 mass%.

The amount of the dispersant in the coloring composition can be adjusted appropriately without particular limitation. The upper limit of the amount of the dispersant in the coloring composition is usually 99% by mass. In addition, considering the viscosity suitable for coating the coloring composition, the lower limit of the amount of the dispersant in the coloring composition is usually 70% by mass, preferably 80% by mass. The above-mentioned dispersant can be used as a solvent for dissolving and removing the precipitate formed by the coloring composition.

(Other additives) Within the scope of not impairing the preferred physical properties of the present invention, the aforementioned coloring composition may be blended with other additives in addition to the aforementioned additives. Other additives include sensitizing pigments, thermal polymerization inhibitors, non-ionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, plasticizers, organic carboxylic acid compounds, organic carboxylic acid anhydrides, pH adjusters, antioxidants, ultraviolet absorbers, light stabilizers, preservatives, mold inhibitors, surfactants, aggregation inhibitors, adhesion improvers, developer improvers, storage stabilizers, etc.

Sensitizing pigments include 4,4'-dimethylaminophenyl ketone, 4,4'-diethylaminophenyl ketone, 2-aminophenyl ketone, 4-aminophenyl ketone, 4,4'-diaminophenyl ketone, 3,3'-diaminophenyl ketone, 3,4-diaminophenyl ketone, 2-(p-dimethylaminophenyl)benzoxazole, 2-(p-diethylaminophenyl)benzoxazole, 2-(p-dimethylaminophenyl)benzo[4,5]benzoxazole, 2-(p-dimethylaminophenyl)benzo[6,7]benzoxazole, 2,5-bis(p-dimethylaminophenyl)benzo[6,7]benzoxazole, 2-(p-diethylaminophenyl)benzothiazole, 2-(p-diethylaminophenyl)benzothiazole, 2-(p-dimethylaminophenyl)benzimidazole, 2-(p-diethylaminophenyl)benzimidazole, 2,5-bis(p-diethylaminophenyl)1,3,4-thiadiazole, (p-dimethylaminophenyl)pyridine, (p-diethylaminophenyl)pyridine, (p-dimethylaminophenyl)quinoline, (p-diethylaminophenyl)quinoline, (p-dimethylaminophenyl)pyrimidine, (p-diethylaminophenyl)pyrimidine, and the like.

Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, pyrogallol, catechol, 2,6-tert-butyl-p-cresol, and β-naphthol.

Non-ionic surfactants include fluorine-based surfactants, silicone-based surfactants, and polyoxyethylene-based surfactants. Anionic surfactants include alkyl sulfonates, alkylbenzene sulfonates, alkylnaphthalene sulfonates, polyoxyethylene alkyl ether sulfonates, alkyl sulfates, alkyl sulfate esters, higher alcohol sulfate esters, aliphatic alcohol sulfate esters, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, and special polymer-based surfactants. Cationic surfactants include quaternary ammonium salts, imidazoline derivatives, and alkylamine salts. Examples of amphoteric surfactants include betaine compounds, imidazolium salts, imidazolines, amino acids, etc.

Examples of the plasticizer include dioctyl phthalate, didodecyl phthalate, triethylene glycol dioctanoate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, triacetyl glycerol, and the like.

Examples of the organic carboxylic acid compound include monocarboxylic acids, carboxylic acids in which a carboxyl group is directly bonded to a phenyl group, and carboxylic acids in which a carboxyl group is bonded to a phenyl group via a carbon bond.

Examples of the organic carboxylic anhydride include acetic anhydride, trichloroacetic anhydride, trifluoroacetic anhydride, tetrahydrophthalic anhydride, succinic anhydride, maleic anhydride, conic anhydride, itaconic anhydride, glutaric anhydride, 1,2-cyclohexene dicarboxylic anhydride, n-octadecyl succinic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, phthalic anhydride, trimellitic anhydride, pyrophyllitic anhydride, naphthalene dicarboxylic anhydride and the like.

>Method for producing coloring composition> The coloring material, dispersant composition, binder resin, dispersant, and optionally a crosslinking agent, photopolymerization initiator, and other additives can be mixed to prepare the coloring composition. Mixing can be performed using, for example, a paint stirrer, a bead mill, a ball mill, a dissolver, a kneader, or other mixing and dispersing machine. The coloring composition is preferably filtered after mixing. The coloring composition has alkaline developing properties and is therefore suitable for use as a color filter.

In addition, the coloring material may be pre-surface-treated with the dispersant composition of the present invention. The surface treatment method may be a dry method in which the dispersant is added and mixed while the coloring material is stirred using a Henschel mixer, a ball mill, an atomizer colloid mill, a Banbury mixer, etc., or a wet method in which the solvent is removed after treatment in a solvent. By performing the surface treatment with the dispersant composition of the present invention as described above, the dispersibility of the coloring material can be improved and aggregation can be prevented.

>Color filter> The color filter of the present invention has a coloring layer formed using the aforementioned coloring composition.

The manufacturing method of the color filter can be exemplified by the following method. First, on a thermoplastic resin sheet such as polyester resin, polyolefin resin, polycarbonate resin, polymethyl methacrylate resin, etc.; a thermosetting resin sheet such as epoxy resin, unsaturated polyester resin, poly(meth)acrylic resin, etc.; or a transparent substrate such as various glasses, color pixels that transmit the three primary colors of red (R), green (G), and blue (B) are provided, preferably a black matrix formed by the aforementioned coloring composition. As a manufacturing method of the color filter, after applying the black coloring composition, pre-baking is performed to evaporate the solvent (dispersion medium) to form a coating film. After the coating is exposed through a photomask, an alkaline developer (aqueous solution containing an organic solvent or a surfactant and an alkaline compound, etc.) is used for development to dissolve and remove the unexposed portion of the coating, thereby forming a black pattern (black matrix). After post-baking as needed, the same operation is repeated in the order of red (R), green (G) and blue (B), thereby obtaining a color filter with a red, green and blue three primary color pixel array on the substrate. However, the order of forming the pixels of each color in the present invention is not limited to the above.

When coating the coloring composition on the substrate, suitable coating methods such as spray coating, roller coating, spin coating, slot die coating, and rod coating can be used, and spin coating and slot die coating are particularly preferred.

After a protective film is formed on the pixel pattern obtained in this way as needed, a transparent conductive film (such as indium tin oxide (ITO)) is formed by sputtering. After the transparent conductive film is formed, a spacer can be further formed to form a color filter.

The color filter of the present invention has high dimensional accuracy and can be suitable for color liquid crystal display elements, color imaging tube elements, color sensors, organic EL display elements, electronic paper, etc.

In addition, the aforementioned coloring composition has low viscosity and excellent dispersibility of the coloring material, so it is suitable for use as a coloring column spacer, which is supported on a thin film transistor (TFT) substrate and a color filter substrate sandwiching a liquid crystal layer. For example, a composition with high optical density (Optical Depth: OD) described in Japanese Patent Publication No. 2015-191234 can be cited.

[Examples] The present invention is further described in detail below based on specific examples. The present invention is not limited to the following examples, and appropriate changes can be made within the scope of the subject matter. In addition, the polymerization rate, weight average molecular weight (Mw), molecular weight distribution (PDI) and amine value of the block copolymer and the adhesive resin, the formaldehyde content of the dispersant composition, and the dispersibility (viscosity) of the coloring composition were evaluated according to the following method.

In addition, the abbreviations are as follows. BA: Butyl acrylate. BMA: Butyl methacrylate. PCL5: 5 mol caprolactone adduct of 2-hydroxyethyl methacrylate (PLACCEL (registered trademark) FM5 manufactured by Daicel Chemical Co., Ltd.). PCL FA5: 5 mol caprolactone adduct of 2-hydroxyethyl acrylate (PLACCEL (registered trademark) FA5 manufactured by Daicel Chemical Co., Ltd.). DMAEMA: Dimethylaminoethyl methacrylate. DMAAm: Dimethylacrylamide. BTEE: Ethyl-2-methyl-2-n-butyltelluryl-propionate. DBDT: Dibutyl ditelluride. AIBN: 2,2'-azobis(isobutyronitrile). PMA: Propylene glycol monomethyl ether acetate.

(Polymerization rate) ¹ H-NMR (solvent: CDCl ₃ , internal standard: TMS) was measured using a nuclear magnetic resonance (NMR) measuring apparatus (model: AVANCE500 (frequency: 500 MHz) manufactured by Bruker BioSpin). The polymerization rate of the monomer was calculated by determining the peak integration ratio derived from the vinyl group of the monomer and the ester side chain of the polymer from the obtained NMR spectrum.

(Weight average molecular weight (Mw) and molecular weight distribution (PDI)) The results were obtained by high-speed liquid chromatography (TOSOH model HLC-8320) using gel permeation chromatography (GPC). The column was SHODEX KF-603 (φ6mm×150mm) (SHODEX), the mobile phase was 10mmol/L lithium bromide/10mmol/L acetic acid/N-methyl-2-pyrrolidone solution, and the detector was a differential refractometer. The measurement conditions were column temperature 40°C, sample concentration 20mg/mL, sample injection volume 10μm, and flow rate 0.2mL/min. The weight average molecular weight (Mw) and number average molecular weight (Mn) were measured by preparing a calibration curve using polystyrene (molecular weight 427,000, 190,000, 96,400, 37,400, 10,200, 2,630, 906) as a standard substance. The molecular weight distribution (PDI = Mw/Mn) was calculated from the measured values.

(Amine value) The amine value is expressed as the mass of potassium hydroxide (KOH) equivalent to 1g of alkaline components in the solid component. The test sample is dissolved in tetrahydrofuran and the resulting solution is neutralized and titrated with 0.1mol/L hydrochloric acid/2-propanol solution using a potentiometric titrator (trade name: GT-06, manufactured by Mitsubishi Chemical Corporation). The inflection point of the titration pH curve is taken as the end point of the titration, and the amine value (B) is calculated by the following formula. B=56.11×Vs×0.1×f/w. B: amine value (mgKOH/g). Vs: amount of 0.1mol/L hydrochloric acid/2-propanol solution required for titration (mL). f: potency of 0.1mol/L hydrochloric acid (2-propanol). w: mass of the test sample (g) (converted to solid component).

(Viscosity) Using an E-type viscometer (trade name: TVE-22L, manufactured by Toki Sangyo Co., Ltd.), the viscosity was measured at 25°C with a conical rotor (1°34'×R24) and a rotor speed of 60 rpm. The coloring composition was stored at 25°C for 2 hours after preparation.

(Formaldehyde amount) Pour 0.5 g of the dispersant composition into an extraction cartridge (Sep Pak (registered trademark) DNPH Silica Plus Cartridge (Product No.: WAT037500) manufactured by WATERS) and leave it at room temperature for 2 hours. The extraction cartridge is filled with silica gel impregnated with DNPH (2,4-dinitrophenylhydrazine). Wash out with 4 mL of acetonitrile and dilute to 5 mL in a volumetric flask. A liquid chromatography instrument (trade name: LC-10AD manufactured by Shimadzu Corporation, column: Pro C18 RS (4.6×250 mm, 5 μm (manufactured by YMC Corporation), mobile phase: acetonitrile/ultrapure water = 65:35 solution, column temperature: 40°C, flow rate: 1.0 mL/min, detection wavelength: 360 nm) was used, and the standard substance was measured using two aldehyde-DNPH mixed standard solutions (0.1 μg aldehyde/μL acetonitrile, manufactured by Wako Pure Chemical Industries, Ltd.). The amount of formaldehyde was calculated from the measurement results.

>Production of block copolymers> (Block copolymer No. 1) PCL FA5 (135.0 g), BA (20.5 g), AIBN (0.82 g), and PMA (103.6 g) were added to a flask equipped with an argon inlet tube and a stirrer. After substitution with argon, BTEE (7.49 g) was added and reacted at 60°C for 21 hours. The polymerization rate was 97.6%.

To the obtained solution, a mixed solution of pre-hydrogen-substituted DMAAm (51.1 g), PMA (34.1 g), and AIBN (0.41 g) were added, and the mixture was reacted at 60° C. for 13 hours. The polymerization rate was 100%.

After the reaction is completed, the reaction solution is injected into the stirred n-heptane. The precipitated polymer is vacuum filtered and dried to obtain block copolymer No. 1. The Mw of the obtained block copolymer No. 1 is 14,614, the PDI is 1.42, and the amine value is 0 mgKOH/g. Table 2 shows the composition of block copolymer No. 1. In addition, the content of each structural unit in the copolymer is calculated from the monomer addition ratio and polymerization rate used in the polymerization reaction.

(Block copolymer No. 2) PCL5 (275.8 g), BMA (45.3 g), AIBN (1.64 g), and PMA (90.3 g) were added to a flask equipped with an argon inlet tube and a stirrer. BTEE (14.99 g) and DBDT (18.47 g) were added after substitution with argon and reacted at 60°C for 10 hours. The polymerization rate was 99.6%.

A mixed solution of DMAEMA (162.6 g) and PMA (40.6 g) which had been pre-substituted with hydrogen was added to the obtained solution, and the mixture was reacted at 60° C. for 11 hours. The polymerization rate was 98.1%.

After the reaction is completed, the reaction solution is injected into the stirred n-heptane. The precipitated polymer is vacuum filtered and dried to obtain block copolymer No. 2. The Mw of the obtained block copolymer No. 2 is 14,797, the PDI is 1.44, and the amine value is 118 mgKOH/g. Table 2 shows the composition of block copolymer No. 2. In addition, the content of each structural unit in the copolymer is calculated from the monomer addition ratio and polymerization rate used in the polymerization reaction.

【Table 1】

>Dispersant composition> 0.325 g of each block copolymer was dissolved in 0.675 g of PMA to prepare a dispersant composition. The formaldehyde content of the dispersant composition was measured and shown in Table 2.

【Table 2】

In dispersant composition No. 2, the B block of the block copolymer of the dispersant does not have the structural unit of the general formula (1), but has a structural unit derived from dimethylaminoethyl methacrylate. The formaldehyde content of the dispersant composition No. 2 is 1.7 ppm, which is relatively high. In contrast, in dispersant composition No. 1, the B block of the block copolymer of the dispersant has the structural unit of the general formula (1). The formaldehyde content of the dispersant composition No. 1 is 0.1 ppm, which is very low.

>Synthesis of alkali-soluble resin (adhesive resin)> In a flask equipped with an argon inlet tube and a stirrer, add methacrylic acid (MAA) (40.0 g), benzyl methacrylate (BzMA) (160.0 g), and propylene glycol monomethyl ether acetate (PMA) (580.0 g), and after substitution with argon, add 2,2'-azobis(isobutyronitrile) (AIBN) (4.0 g), n-dodecanethiol (6.0 g), and PMA (20.0 g), and heat to 90°C. While the solution is kept at 90°C, MAA (80.0 g), BzMA (320.0 g), AIBN (8.0 g), n-dodecanethiol (12.0 g), and PMA (50.0 g) are dripped into the solution over 1.5 hours. 60 minutes after the completion of the dropwise addition, the temperature was raised to 110°C, AIBN (0.8 g) and PMA (10.0 g) were added and reacted for 1 hour, AIBN (0.8 g) and PMA (10.0 g) were further added and reacted for 1 hour, and AIBN (0.8 g) and PMA (10.0 g) were further added and reacted for 1 hour.

The obtained reaction solution was cooled to room temperature, and PMA (240.0 g) was added to obtain an alkali-soluble resin solution with a non-volatile content of 39.5%. The weight average molecular weight (Mw) of the alkali-soluble resin was 9,150, the molecular weight distribution (PDI) was 1.92, and the acid value was 128 mgKOH/g.

>Preparation of coloring composition> Coloring composition No.1-1, 1-2 The blending composition was prepared by 8 parts by weight of pigment, 6 parts by weight of block copolymer No.1, 6 parts by weight of alkali-soluble resin, and 80 parts by weight of PMA. 555 parts by weight of 0.3 mm zirconium dioxide beads were added and mixed for 3 hours and fully dispersed using a bead mill (trade name: DISPERMATCA, manufactured by VMA-GETZMANN GmbH). After dispersion, the beads were filtered to obtain the coloring composition. C.I. Pigment Red 254 (trade name: BKCF, manufactured by Ciba Specialty Chemicals) or C.I. Pigment Green 58 (trade name: FASTOGEN (registered trademark) GREEN A310, manufactured by DIC Corporation) was used as the pigment to prepare coloring composition No.1-1 (red composition) and coloring composition No.1-2 (green composition). The dispersibility of the obtained red composition and green composition was evaluated, and the viscosity of each composition was less than 30 mPa･s.

Coloring composition No.2-1, 2-2 Coloring composition No.2-1 (red composition) and coloring composition No.2-2 (green composition) were prepared in the same manner as coloring composition No.1-1, 1-2 except that the block copolymer was changed. The dispersibility of the obtained red composition and green composition was evaluated, and the viscosity of each composition was less than 30mPa･s.

The viscosity of the coloring compositions No. 1-1 and 1-2 is less than 30 mPa･s, and the pigment dispersibility is good like the coloring compositions No. 2-1 and 2-2. Therefore, it can be understood that the block copolymer having the structural unit of the general formula (1) in the B block can be used as a dispersant even though it does not have an amine group or a quaternary ammonium alkali. Therefore, it can be seen that if the block copolymer having the structural unit of the general formula (1) in the B block is used, a coloring composition with reduced formaldehyde content and excellent pigment dispersibility can be obtained.

The present invention includes the following embodiments. (Embodiment 1) A dispersant composition comprises a polymer having a structural unit represented by the general formula (1).

[Chemical formula 6] [In the general formula (1), R ¹¹ represents a hydrogen atom or a chain or cyclic hydrocarbon group which may have a substituent. R ¹² represents a chain or cyclic hydrocarbon group which may have a substituent. R ¹¹ and R ¹² may be bonded to each other to form a ring structure. R ¹³ represents a hydrogen atom or a methyl group.]

(Implementation Example 2) The dispersant composition described in Example 1, wherein the amine value of the aforementioned polymer is less than 10 mgKOH/g.

(Implementation Example 3) A dispersant composition as described in Example 1 or 2, wherein the aforementioned polymer is a block copolymer having an A block and a B block, the aforementioned A block has a structural unit derived from a (meth)acrylic acid-based monomer, and the aforementioned B block has a structural unit represented by the aforementioned general formula (1).

(Implementation Example 4) The dispersant composition described in Example 3, wherein the aforementioned A block has a structural unit represented by the general formula (10).

[Chemical formula 7] [In the general formula (10), n1 represents an integer of 1 to 10. ^R1 represents a hydrogen atom or a methyl group. ^R2 represents an alkylene group having 1 to 10 carbon atoms. ^R3 represents an alkylene group having 1 to 10 carbon atoms.]

(Implementation Example 5) A dispersant composition as described in Example 3 or 4, wherein the mass ratio of the A block to the B block in the aforementioned block copolymer (A block/B block) is 50/50 or more.

(Implementation Example 6) A dispersant composition as described in any one of Examples 3 to 5, wherein the molecular weight distribution (PDI) of the block copolymer is less than 2.5.

(Implementation Example 7) A dispersant composition as described in any one of Examples 3 to 6, wherein the block copolymer is polymerized by living free radical polymerization.

(Implementation Example 8) A coloring composition comprises a dispersant composition as described in any one of Examples 1 to 7, a coloring material, a binder resin and a dispersant.

(Implementation Example 9) The coloring composition described in Example 8 is used for a color filter.

(Implementation Example 10) A color filter having a coloring layer formed by the coloring composition described in Example 9.

Claims (10)

A dispersant composition is a block copolymer comprising an A block having a structural unit represented by the general formula (10) and a B block having a structural unit represented by the general formula (1).

In the general formula (10), n1 represents an integer of 1 to 10, ^R1 represents a hydrogen atom or a methyl group, ^R2 represents an alkylene group having 1 to 10 carbon atoms, and ^R3 represents an alkylene group having 1 to 10 carbon atoms.

In the general formula (1), R ¹¹ represents a hydrogen atom or a chain or cyclic hydrocarbon group which may have a substituent, R ¹² represents a chain or cyclic hydrocarbon group which may have a substituent, R ¹¹ and R ¹² may be bonded to each other to form a ring structure, and R ¹³ represents a hydrogen atom or a methyl group. The dispersant composition as described in claim 1, wherein the amine value of the aforementioned block copolymer is less than 10 mgKOH/g. The dispersant composition as described in claim 1, wherein in the aforementioned general formula (1), R ¹¹ represents a chain or cyclic hydrocarbon group which may have a substituent, and R ¹² represents a chain or cyclic hydrocarbon group which may have a substituent, or R ¹¹ represents a hydrogen atom, and R ¹² represents a chain hydrocarbon group which may have at least one substituent selected from the group consisting of a halogen group and a benzoyl group, or a cyclic hydrocarbon group which may have a substituent. The dispersant composition as described in claim 1, wherein the content of the structural unit represented by the aforementioned general formula (10) is greater than 10% by mass and less than 95% by mass in 100% by mass of the A block. The dispersant composition as described in claim 1, wherein the mass ratio of block A to block B in the aforementioned block copolymer (block A/block B) is 50/50 or more. The dispersant composition as described in claim 1, wherein the molecular weight distribution (PDI) of the aforementioned block copolymer is less than 2.5. A dispersant composition as described in any one of claims 1 to 6, wherein the block copolymer is polymerized by living free radical polymerization. A coloring composition comprising a dispersant composition as described in any one of claim 1 to claim 7, a coloring material, a binder resin and a dispersant. The coloring composition as described in claim 8 is used for color filters. A color filter having a coloring layer formed using the coloring composition described in claim 9.