WO2024116876A1

WO2024116876A1 - Block copolymer, dispersant, and coloring composition

Info

Publication number: WO2024116876A1
Application number: PCT/JP2023/041305
Authority: WO
Inventors: 翔池田; 弘一郎宮崎
Original assignee: 大塚化学株式会社
Priority date: 2022-12-02
Filing date: 2023-11-16
Publication date: 2024-06-06

Abstract

[Problem] To provide a block copolymer having high colorant dispersing ability when being used as a dispersant for a coloring composition. [Solution] This block copolymer is characterized by having a segment A and a segment B, and is characterized in that the segment A substantially does not include a structural unit (b-2) having a basic group, the segment B includes a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group, and the mole ratio ((b-1)/(b-2)) of the structural unit (b-1) and the structural unit (b-2) in the segment B is 5/95 to 95/5.

Description

Block copolymer, dispersant, and coloring composition

The present invention relates to a block copolymer, and in particular to a block copolymer that can be used as a dispersant for a colorant in a coloring composition.

　Traditionally, in the manufacture of color filters used in liquid crystal displays and the like, methods of applying coloring materials to a substrate include dyeing, printing, inkjet, electrodeposition, and pigment dispersion. Among these, the pigment dispersion method is mainstream from the viewpoints of spectral characteristics, durability, pattern shape, and precision. In this pigment dispersion method, a coating film made of a coloring composition containing a mixture of pigment, dispersant, dispersion medium (solvent), binder resin, etc. is formed on a substrate, and is cured by irradiating radiation through a photomask with the desired pattern shape, followed by alkaline development.

In recent years, increasing the concentration of pigments in coloring compositions has been studied in order to obtain good color reproducibility and high contrast in color filters. When increasing the concentration of pigments, the proportion of dispersant decreases relatively, so the dispersant is required to have high dispersibility (see, for example, Patent Document 1 (paragraph 0004)). In addition, in alkaline development, binder resins having alkali solubility play a major role. However, in the case of pigment dispersion compositions with high pigment concentrations, the proportion of binder resin, which is a developing component, decreases, and alkaline developability decreases. Therefore, the alkaline developability that was originally required of binder resins is also required of dispersants. As such a dispersant, Patent Document 2 describes the use of an A-B block copolymer consisting of an A block having a polylactone chain in the side chain and a B block having a tertiary amino group in the side chain as a pigment dispersion (see Patent Document 2 (paragraphs 0023 to 0045)).

JP 2009-265515 A JP 2013-119568 A

In resin-type dispersants, it has been proposed to introduce a tertiary amino group into the side chain in order to improve the dispersibility of colorants (see Patent Document 2). However, due to the recent trend toward higher concentrations of colorants in coloring compositions, further improvements in dispersibility are required.

The present invention was made in consideration of the above circumstances, and aims to provide a block copolymer that has high dispersibility of coloring materials when used as a dispersant for a coloring composition.

The block copolymer of the present invention, which has been able to solve the above problems, is a block copolymer having an A segment and a B segment, wherein the A segment is substantially free of a structural unit (b-2) having a basic group, the B segment contains a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group, and the molar ratio ((b-1)/(b-2)) of the structural unit (b-1) to the structural unit (b-2) in the B segment is 5/95 to 95/5.

The block copolymer of the present invention is designed so that the A segment has a high affinity with the solvent and the B segment has a high affinity with the colorant, and the basic group introduced into the B segment adsorbs to the colorant. Here, it is believed that the affinity between the adsorption site and the dispersion medium is increased by copolymerizing the structural unit (b-1) having a hydroxyl group that easily interacts with the solvent into the B segment. Therefore, by controlling the molar ratio ((b-1)/(b-2)) of the structural unit (b-1) to the structural unit (b-2) in the B segment within a predetermined range, it is possible to maintain the affinity of the B segment with the colorant while also increasing its affinity with the dispersion medium, and it is believed that the ability of the block copolymer to disperse the colorant can be further improved.

The block copolymer of the present invention has excellent dispersibility for colorants, and when used as a dispersant for colorants, a colored composition with excellent viscosity stability can be obtained.

Below, an example of a preferred embodiment of the present invention will be described. However, the following embodiment is merely an example. The present invention is not limited to the following embodiment in any way.

<Block copolymer>
The block copolymer of the present invention has an A segment and a B segment. In this specification, the term "A segment" refers to a portion of the copolymer that is composed of the "A block," and the term "B segment" refers to a portion of the copolymer that is composed of the "B block." In this specification, the term "vinyl monomer" refers to a monomer having a radically polymerizable carbon-carbon double bond in the molecule. The term "structural unit derived from a vinyl monomer" refers to a structural unit in which the radically polymerizable carbon-carbon double bond of a vinyl monomer is polymerized to become a carbon-carbon single bond. "(Meth)acrylic" refers to "at least one of acrylic and methacrylic.""(Meth)acrylate" refers to "at least one of acrylate and methacrylate.""(Meth)acrylate" means "an ester compound in which the hydrogen atom of the carboxyl group of (meth)acrylic acid is substituted with an organic group.""(Meth)acryloyl" refers to "at least one of acryloyl and methacryloyl.""(Meth)acrylicmonomer" means "a monomer having a (meth)acryloyl group in the molecule," and includes "(meth)acrylate." The term "vinyl monomer" also includes "(meth)acrylate" and "(meth)acrylic monomer."

In this specification, when it is stated that "X to Y" (X and Y are any numbers), it means "X or more, Y or less." In addition, when it is stated that "X or more" (X is any number), it includes the meaning of "X or more than X," and when it is stated that "Y or less" (Y is any number), it also includes the meaning of "Y or less than Y."
Furthermore, "X and/or Y (X and Y are optional)" means "at least one of X and Y", and means three possibilities: "X only", "Y only", and "X and Y".

(A segment)
The A segment refers to a portion of the block copolymer that is composed of an A block. The block copolymer may have only one A block as the A segment, or may have multiple A blocks as the A segment. When the A segment has multiple A blocks, these A blocks may have the same composition or different compositions. The A segment does not substantially contain a structural unit (b-2) having a basic group.

The A block is a block that does not substantially contain a structural unit (b-2) having a basic group. Examples of structural units constituting the A block include structural units derived from (meth)acrylic monomers and structural units derived from vinyl monomers other than (meth)acrylic monomers. The structural units constituting the A block may be of only one type, or may have two or more types. When two or more types of structural units are contained in the A block, 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, and are preferably contained in the A block in the form of random copolymerization from the viewpoint of uniformity.

Examples of the (meth)acrylic monomer that forms a structural unit derived from the (meth)acrylic monomer include (meth)acrylic monomers having a chain alkyl group, (meth)acrylic monomers having a cyclic alkyl group, (meth)acrylic monomers having an aryl group, (meth)acrylic monomers having a hydroxy group, (meth)acrylic monomers having an alkoxy group, (meth)acrylic monomers having an oxygen-containing heterocyclic group, (meth)acrylic monomers having an amide group, (meth)acrylic monomers having an acidic group, etc.

Examples of (meth)acrylic monomers having a chain alkyl group include (meth)acrylates having a straight-chain alkyl group and (meth)acrylates having a branched-chain alkyl group.

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

As the (meth)acrylate having a branched alkyl group, a (meth)acrylate having a branched alkyl group with a carbon number of 3 to 20 is preferred, and a (meth)acrylate having a branched alkyl group with a carbon number of 3 to 10 is preferred. Specific examples of the (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, etc.

Examples of the (meth)acrylic monomer having a cyclic alkyl group include (meth)acrylates having a cyclic alkyl group with a monocyclic structure and (meth)acrylates having a cyclic alkyl group with a bridged ring structure.

The (meth)acrylate having a cyclic alkyl group with a monocyclic structure is preferably a (meth)acrylate having a cyclic alkyl group with a monocyclic structure in which the cyclic alkyl group has 6 to 12 carbon atoms. Specific examples of (meth)acrylates having a cyclic alkyl group with a monocyclic structure include cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, and cyclododecyl (meth)acrylate.

The (meth)acrylate having a cyclic alkyl group with a bridged ring structure is preferably a (meth)acrylate having a bridged ring structure with a carbon number of 6 to 12. Specific examples of (meth)acrylates having a cyclic alkyl group with a bridged ring structure include isobornyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentanyloxyethyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, and 2-ethyl-2-adamantyl (meth)acrylate.

The (meth)acrylic monomer having an aryl group is preferably a (meth)acrylate having an aryl group with 6 to 12 carbon atoms. The aryl group may have a chain portion such as an alkylaryl group, an aralkyl group, or an aryloxyalkyl group. Specific examples of (meth)acrylates having an aryl group include benzyl (meth)acrylate, phenyl (meth)acrylate, and phenoxyethyl (meth)acrylate.

Examples of the (meth)acrylic monomer having a hydroxy group include (meth)acrylates having a hydroxyalkyl group, (meth)acrylates having a lactone-modified hydroxy group, and (meth)acrylates having a polyalkylene glycol group.

Specific examples of (meth)acrylates having the hydroxyalkyl 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, and 12-hydroxylauryl (meth)acrylate. The hydroxyalkyl group is preferably linear or branched. The number of carbon atoms in the hydroxyalkyl group is preferably 1 to 10, and more preferably 1 to 5.

Specific examples of the (meth)acrylate having a lactone-modified hydroxy group include those obtained by adding lactone to the (meth)acrylate having a hydroxyalkyl group, and those obtained by adding caprolactone are preferred. The amount of caprolactone added is preferably 1 mol to 20 mol, and more preferably 1 mol to 10 mol. Preferred examples of the (meth)acrylate having a lactone-modified hydroxy group include 1 mol caprolactone adduct of 2-hydroxyethyl (meth)acrylate, 2 mol caprolactone adduct of 2-hydroxyethyl (meth)acrylate, 3 mol caprolactone adduct of 2-hydroxyethyl (meth)acrylate, 4 mol caprolactone adduct of 2-hydroxyethyl (meth)acrylate, 5 mol caprolactone adduct of 2-hydroxyethyl (meth)acrylate, and 10 mol caprolactone adduct of 2-hydroxyethyl (meth)acrylate.

Specific examples of (meth)acrylates having the polyalkylene glycol group include mono(meth)acrylate with a terminal hydroxyl group, polyethylene glycol (degree of polymerization = 2 to 10), mono(meth)acrylate with a terminal hydroxyl group, polypropylene glycol (degree of polymerization = 2 to 10), etc.

Examples of the (meth)acrylic monomer having an alkoxy group include (meth)acrylates having an alkoxyalkyl group and (meth)acrylates having an alkoxypolyalkylene glycol group.

Specific examples of (meth)acrylates having the above-mentioned alkoxyalkyl groups include methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, etc.

Specific examples of (meth)acrylates having an alkoxy polyalkylene glycol group include (meth)acrylates having a polyethylene glycol structure such as polyethylene glycol (degree of polymerization = 2-10) methyl ether (meth)acrylate, polyethylene glycol (degree of polymerization = 2-10) ethyl ether (meth)acrylate, and polyethylene glycol (degree of polymerization = 2-10) propyl ether (meth)acrylate; 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, and polypropylene glycol (degree of polymerization = 2-10) propyl ether (meth)acrylate.

The (meth)acrylic monomer having an oxygen-containing heterocyclic group is preferably a (meth)acrylate having a 4- to 6-membered oxygen-containing heterocyclic group. Specific examples of (meth)acrylates having an oxygen-containing heterocyclic group include glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, (3-ethyloxetan-3-yl)methyl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)methyl (meth)acrylate, cyclic trimethylolpropane formal (meth)acrylate, and 2-[(2-tetrahydropyranyl)oxy]ethyl (meth)acrylate.

Specific examples of the (meth)acrylic monomer having an amide group include N,N-dimethyl(meth)acrylamide and 4-(meth)acryloylmorpholine.

Examples of the acidic group contained in the (meth)acrylic monomer having an acidic group include a carboxy group (-COOH), a sulfonic acid group (-SO ₃ H), a phosphoric acid group (-OPO ₃ H ₂ ), a phosphonic acid group (-PO ₃ H ₂ ), and a phosphinic acid group (-PO ₂ H ₂ ). Examples of the (meth)acrylic monomer having an acidic group include (meth)acrylic acid, a (meth)acrylate having a carboxy group, a (meth)acrylate having a phosphoric acid group, and a (meth)acrylate having a sulfonic acid group, and preferably, (meth)acrylic acid and a (meth)acrylate having a carboxy group.

Specific examples of (meth)acrylates having a carboxy group include monomers obtained by reacting (meth)acrylates having a hydroxyalkyl group, such as carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, and 2-(meth)acryloyloxyethyl phthalate, with acid anhydrides, such as maleic anhydride, succinic anhydride, and phthalic anhydride. Specific examples of (meth)acrylates having a phosphoric acid group include 2-(phosphonooxy)ethyl (meth)acrylate. Specific examples of (meth)acrylates having a sulfonic acid group include ethyl sulfonate (meth)acrylate.

The structural units derived from vinyl monomers other than the (meth)acrylic monomer are not particularly limited as long as they are formed from vinyl monomers that can be copolymerized with both the (meth)acrylic monomer and the vinyl monomer that forms the B block described below.

Specific examples of vinyl monomers that form structural units derived from vinyl monomers other than the (meth)acrylic monomers include α-olefins, styrene-based monomers, vinyl monomers containing a hydroxyl group, vinyl monomers containing a heterocycle, vinyl amides, vinyl carboxylates, dienes, etc. These vinyl monomers may have a hydroxyl group or an epoxy group.

Examples of the α-olefin include 1-hexene, 1-octene, and 1-decene.
The styrene-based monomer may be substituted or unsubstituted styrene. Examples of the substituent that may be substituted on styrene include an alkyl group, an aryl group, an alkoxy group, and an aryloxy group. The styrene-based monomer also includes a condensed ring compound having two or more benzene rings. Specific examples of the styrene-based vinyl monomer include styrene, α-methylstyrene, 4-methylstyrene, 2-methylstyrene, 3-methylstyrene, 2,4-dimethylstyrene, 4-methoxystyrene, 4-phenylstyrene, 2-hydroxymethylstyrene, and 1-vinylnaphthalene.
Examples of the vinyl monomer containing a hydroxy group include 4-vinylphenol and 4-hydroxybutyl vinyl ether.
Examples of the vinyl monomer containing a heterocycle include 2-vinylthiophene, N-methyl-2-vinylpyrrole, and 1-vinyl-2-pyrrolidone.
Examples of the vinyl amide include N-vinylformamide, N-vinylacetamide, and N-vinyl-ε-caprolactam.
Examples of the vinyl carboxylate include vinyl acetate, vinyl pivalate, and vinyl benzoate.
Examples of the dienes include butadiene, isoprene, 4-methyl-1,4-hexadiene, and 7-methyl-1,6-octadiene.

The A block preferably contains a structural unit derived from a (meth)acrylic monomer. The structural unit derived from the (meth)acrylic monomer may be of only one type, or may have two or more types. When the A block contains a structural unit derived from a (meth)acrylic monomer, the affinity with the dispersion medium and the binder resin blended in the coloring composition is improved.

The content of the structural units derived from the (meth)acrylic monomer is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and particularly preferably 100 mol% out of 100 mol% of the structural units constituting the A block.

When the A segment has multiple A blocks, the content of the structural units derived from the (meth)acrylic monomer is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and particularly preferably 100 mol% in 100 mol% of the structural units constituting the A segment.

The A segment preferably contains a structural unit derived from at least one (meth)acrylic monomer selected from the group consisting of (meth)acrylic monomers having a chain alkyl group, (meth)acrylic monomers having a cyclic alkyl group, (meth)acrylic monomers having an aryl group, (meth)acrylic monomers having a hydroxy group, (meth)acrylic monomers having an alkoxy group, (meth)acrylic monomers having an oxygen-containing heterocyclic group, (meth)acrylic monomers having an amide group, and (meth)acrylic monomers having an acidic group. By containing structural units derived from these (meth)acrylic monomers, the affinity with the dispersion medium and the binder resin blended in the coloring composition is further improved.

The A segment preferably contains, as a structural unit derived from a (meth)acrylic monomer, at least one structural unit derived from a (meth)acrylic monomer selected from the group consisting of structural unit (a-1) derived from a (meth)acrylate having a hydroxy group and structural unit (a-2) derived from a (meth)acrylate having an alkoxy group, more preferably structural unit (a-1) derived from a (meth)acrylate having a hydroxy group, and even more preferably structural unit derived from a (meth)acrylate having a lactone-modified hydroxy group. The A segment having a hydroxy group or alkoxy group can further improve the dispersion performance of the colorant, and among them, the structural unit derived from a (meth)acrylate having a lactone-modified hydroxy group has an ester bond portion and a terminal hydroxy group in the side chain, and therefore has high affinity with the dispersion medium and binder resin, and enhances re-solubility in the dispersion medium.

As the structural unit derived from the (meth)acrylate having a lactone-modified hydroxy group, a structural unit represented by formula (4) is preferred.

[In formula (4), n1 represents an integer of 1 to 10. R ⁴¹ represents a hydrogen atom or a methyl group. R ⁴² represents an alkylene group having 1 to 10 carbon atoms. R ⁴³ represents an alkylene group having 1 to 10 carbon atoms.]

In formula (4), n1 is preferably an integer from 1 to 7, and more preferably an integer from 1 to 5.

The alkylene group having 1 to 10 carbon atoms represented by R ⁴² may be either linear or branched, but is preferably linear. Specific examples of the alkylene group having 1 to 10 carbon atoms represented by R ⁴² include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, a decamethylene group, and a 1-methylethylene group. R ⁴² is preferably an alkylene group having 1 to 5 carbon atoms.

The alkylene group having 1 to 10 carbon atoms represented by R ⁴³ may be either linear or branched, but is preferably linear. Specific examples of the alkylene group having 1 to 10 carbon atoms represented by R ⁴³ include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, and a decamethylene group. R ⁴³ is preferably an alkylene group having 1 to 8 carbon atoms, and more preferably an alkylene group having 3 to 8 carbon atoms.

When the A segment contains structural units (a-1) derived from a (meth)acrylate having a hydroxy group and/or structural units (a-2) derived from a (meth)acrylate having an alkoxy group, the total content thereof is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 20 mol% or more, and preferably 95 mol% or less, more preferably 70 mol% or less, and even more preferably 40 mol% or less, in 100 mol% of the structural units constituting the A segment. By setting the total content of structural units (a-1) derived from a (meth)acrylate having a hydroxy group and structural units (a-2) derived from a (meth)acrylate having an alkoxy group within the above range, the dispersion performance of the colorant can be further improved.

When the A segment contains a structural unit derived from a (meth)acrylate having a lactone-modified hydroxy group, the content is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 20 mol% or more, and is preferably 95 mol% or less, more preferably 70 mol% or less, even more preferably 40 mol% or less, in 100 mol% of the structural units constituting the A segment. By setting the content of the structural unit derived from a (meth)acrylate having a lactone-modified hydroxy group within the above range, the resolubility of the coloring composition containing the block copolymer can be increased.

The A segment may have a structural unit derived from a vinyl monomer having an acidic group (preferably a (meth)acrylic monomer having an acidic group, more preferably (meth)acrylic acid). By having a structural unit derived from a vinyl monomer having an acidic group, the solubility in an alkaline developer is increased, and the alkaline developability of the coloring composition can be improved. However, if the proportion is high, there is a risk that the affinity with the dispersion medium and binder resin will be reduced. Therefore, it is preferable that the proportion of structural units derived from a vinyl monomer having an acidic group is such that the overall acid value of the block copolymer is lower than the amine value.

When structural units derived from vinyl monomers having acidic groups are contained, the content is preferably 2 mol% or more, and preferably 20 mol% or less, in 100 mol% of the structural units constituting the A segment. If the content of structural units derived from vinyl monomers having acidic groups is 2 mol% or more, the dissolution rate when neutralized with alkali during alkaline development is increased, and if it is 20 mol% or less, the hydrophilicity is not too high, and it is possible to prevent the formed pixels from becoming disordered.

The A segment does not substantially contain structural units (b-2) having a basic group. In other words, it is preferable that the monomers constituting the A segment do not contain monomers having a basic group. If a basic group is present in the A segment, when used as a dispersant, the colorant will be adsorbed by both the A segment and the B segment, and the dispersibility of the colorant will decrease. The content of structural units (b-2) having a basic group in 100 mol% of the structural units constituting the A segment is preferably 0.5 mol% or less, more preferably 0.1 mol% or less, even more preferably 0.05 mol% or less, and particularly preferably 0 mol%.

(B segment)
The B segment refers to a portion of the block copolymer that is composed of a B block. The block copolymer may have only one B block as the B segment, or may have multiple B blocks as the B segment. When the B segment has multiple B blocks, these B blocks may have the same composition or different compositions.

The B segment contains a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group. Examples of the B segment include an embodiment containing a B block containing a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group; an embodiment containing a B1 block containing a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group, and a B2 block containing a structural unit (b-2) having a basic group; an embodiment containing a B1 block containing a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group, and a B2 block containing a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group, and a B2 block containing a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group, and the like.

The B block is a block containing a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group, or a block containing no structural unit (b-1) having a hydroxy group and containing a structural unit (b-2) having a basic group. 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, and from the viewpoint of uniformity, they are preferably contained in the form of random copolymerization.

(Structural unit (b-1) having a hydroxy group)
At least one block of the B block contains a structural unit (b-1) having a hydroxy group. When at least one block of the B block contains the structural unit (b-1), the affinity to the dispersion medium can be increased. The structural unit (b-1) may be of only one type, or may have two or more types. Note that the structural unit (b-2) having a basic group, which will be described later, is not included in the structural unit (b-1) having a hydroxy group.

The structural unit (b-1) may be, for example, a structure derived from a vinyl monomer having a hydroxyl group. The structural unit (b-1) having a hydroxyl group is preferably a structural unit represented by formula (1).

[In formula (1), R ¹¹ represents a hydrogen atom or a methyl group. A ¹¹ represents an ester group, an amide group, or a single bond. R ¹² represents a divalent hydrocarbon group, -R ¹³ -(OCO-R ¹⁴ ) _m - group, or -R ¹⁵ -(O-R ¹⁶ ) _n - group. R ¹³ to R ¹⁶ each independently represent a divalent hydrocarbon group. m represents an integer from 1 to 10. n represents an integer from 1 to 10.]

The A ¹¹ represents an ester group (-CO-O-), an amide group (-CO-NH-) or a single bond, and is preferably an ester group or an amide group in terms of affinity to the dispersion medium and alkaline developability. The bonding direction of the ester group or the amide group is not particularly limited. Examples of the bonding mode of the ester group include C-CO-O-R ¹² or C-O-CO-R ¹² , and C-CO-O-R ¹² is preferred. Examples of the bonding mode of the amide group include C-CO-NH-R ¹² or C-NH-CO-R ¹² , and C-CO-NH-R ¹² is preferred.

The divalent hydrocarbon group represented by R ¹² includes a linear alkylene group, a branched alkylene group, a cyclic alkylene group, and an arenediyl group, with linear alkylene groups and branched alkylene groups being preferred.

The linear alkylene group preferably has 1 to 20 carbon atoms, more preferably has 1 to 10 carbon atoms, and further preferably has 1 to 5 carbon atoms. Examples of the linear alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, a decamethylene group, and a dodecamethylene group.
The branched alkylene group preferably has a carbon number of 3 to 20, and more preferably has a carbon number of 3 to 10. Examples of the branched alkylene group include a propylene group, a propylidene group, a 1,2-butanediyl group, and a 1,3-butanediyl group.
The cyclic alkylene group preferably has a carbon number of 6 to 12. Examples of the cyclic alkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, and a cyclohexylene group.
The arenediyl group preferably has a carbon number of 6 to 12, and more preferably has a carbon number of 6 to 9. Examples of the arenediyl group include a phenylene group.

R ¹³ and R ¹⁴ in the —R ¹³ —(OCO—R ¹⁴ ) _m — group represented by R ¹² each independently represent a divalent hydrocarbon group. m represents an integer of 1 to 10, preferably an integer of 1 to 7, and more preferably an integer of 1 to 5.

The divalent hydrocarbon group of R ¹³ includes a linear alkylene group and a branched alkylene group, and is preferably a linear alkylene group. The linear alkylene group preferably has 1 to 10 carbon atoms, and more preferably has 1 to 5 carbon atoms. The branched alkylene group preferably has 3 to 10 carbon atoms, and more preferably has 3 to 5 carbon atoms. Specific examples of R ¹³ include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, a decamethylene group, and a 1-methylethylene group.

The divalent hydrocarbon group of R ¹⁴ includes a linear alkylene group, a branched alkylene group, etc., and a linear alkyl group is preferred. The linear alkylene group preferably has 1 to 10 carbon atoms, more preferably has 1 to 8 carbon atoms, and even more preferably has 3 to 8 carbon atoms. The branched alkylene group preferably has 3 to 10 carbon atoms, and more preferably has 3 to 8 carbon atoms. Specific examples of R ¹⁴ include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonamethylene group, and a decamethylene group.

R ¹⁵ and R ¹⁶ in the —R ¹⁵ —(O—R ¹⁶ ) _n — group represented by R ¹² each independently represent a divalent hydrocarbon group.

The divalent hydrocarbon group of R ¹⁵ includes a linear alkylene group and a branched alkylene group, and a linear alkyl group is preferable. The linear alkylene group preferably has 1 to 5 carbon atoms, and more preferably has 1 to 3 carbon atoms. The branched alkylene group preferably has 3 to 5 carbon atoms. Specific examples of R ¹⁵ include a methylene group, an ethylene group, and a propylene group.

The divalent hydrocarbon group of R ¹⁶ includes a linear alkylene group and a branched alkylene group, and a branched alkylene group is preferable. The linear alkylene group preferably has 1 to 5 carbon atoms, and more preferably has 1 to 3 carbon atoms. The branched alkylene group preferably has 3 to 5 carbon atoms. Specific examples of R ¹⁶ include a methylene group, an ethylene group, and a propylene group.

Specific examples of vinyl monomers that form the structural unit represented by formula (1) are preferably (meth)acrylates having a hydroxyalkyl group, (meth)acrylates having a lactone-modified hydroxy group, (meth)acrylates having a polyalkylene glycol group, and vinyl monomers having a hydroxy group.

Examples of (meth)acrylates having a hydroxyalkyl 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, and 2-hydroxy-3-phenoxypropyl (meth)acrylate.

Examples of the (meth)acrylate having a lactone-modified hydroxy group include 1 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone, 2 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone, 3 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone, 4 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone, 5 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone, and 10 mol adduct of 2-hydroxyethyl (meth)acrylate with caprolactone.

Examples of the (meth)acrylate having a polyalkylene glycol group include mono(meth)acrylate with a terminal hydroxyl group, polyethylene glycol (degree of polymerization = 2 to 10), mono(meth)acrylate with a terminal hydroxyl group, polypropylene glycol (degree of polymerization = 2 to 10), etc.

Examples of vinyl monomers containing a hydroxy group include 4-vinylphenol and 4-hydroxybutyl vinyl ether.

In 100 mol% of the structural units constituting the B segment, the content of the structural unit (b-1) is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and is preferably 90 mol% or less, more preferably 80 mol% or less, even more preferably 65 mol% or less. If the content of the structural unit (b-1) is within the above range, it is considered that the B segment has high affinity with the colorant.

In the B block containing the structural unit (b-1), the content of the structural unit (b-1) in 100 mol% of the structural units constituting the B block is preferably more than 0 mol%, more preferably 1 mol% or more, even more preferably 10 mol% or more, and is preferably 99 mol% or less, more preferably 80 mol% or less, even more preferably 65 mol% or less.

(Structural Unit (b-2) Having a Basic Group)
The B block constituting the B segment contains a structural unit (b-2) having a basic group. By containing the structural unit (b-2), the copolymer has high adsorption ability for colorants. The structural unit (b-2) may be of only one type, or may have two or more types.

The basic group is a group that exhibits basicity, and is preferably an amino group in terms of availability of raw materials and ease of synthesis. In this specification, the amino group includes, in addition to a general amino group (-NH ₂ ), a substituted amino group represented by -NHR ^a or -NR ^a R ^b (R ^a and R ^b each independently represent a chain or cyclic hydrocarbon group. R ^a and R ^b may be bonded to each other to form a cyclic structure) in which H is substituted with a hydrocarbon group, and a nitrogen-containing heterocyclic group (pyridyl group, imidazole group, etc.). In this specification, a hydroxy group is not included in the basic group.

The structural unit (b-2) can be, for example, a structure derived from a vinyl monomer having a basic group.

The structural unit (b-2) is preferably a structural unit represented by formula (2).

[In formula (2), ^R21 represents a hydrogen atom or a methyl group. ^A21 represents an ester group, an amide group, or a single bond. ^R22 represents a divalent hydrocarbon group. ^R23 and ^R24 each independently represent a hydrocarbon group that may contain a heteroatom. ^R23 and ^R24 may be bonded to each other to form a cyclic structure.]

The A ²¹ represents an ester group (-CO-O-), an amide group (-CO-NH-) or a single bond, and is preferably an ester group or an amide group in terms of affinity to the dispersion medium and alkaline developability. The bonding direction of the ester group or the amide group is not particularly limited. Examples of the bonding mode of the ester group include C-CO-O-R ²² or C-O-CO-R ²² , and C-CO-O-R ²² is preferred. Examples of the bonding mode of the amide group include C-CO-NH-R ²² or C-NH-CO-R ²² , and C-CO-NH-R ²² is preferred.

The divalent hydrocarbon group represented by R ²² includes a linear alkylene group, a branched alkylene group, a cyclic alkylene group, an alkenylene group, an arenediyl group, etc., and the linear alkylene group is preferred.
The linear alkylene group preferably has a carbon number of 1 to 10, and more preferably has a carbon number of 1 to 5. Examples of the linear alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a pentamethylene group.
The branched alkylene group preferably has a carbon number of 3 to 10. Examples of the branched alkylene group include a propylene group, a propylidene group, a 1,2-butanediyl group, and a 1,3-butanediyl group.
The cyclic alkylene group preferably has a carbon number of 6 to 12. Examples of the cyclic alkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, and a cyclohexylene group.
The alkenylene group preferably has a carbon number of 2 to 10. Examples of the alkenylene group include an ethenylene group, a 2-propenylene group, a 2-butenylene group, and a 3-butenylene group.
The arenediyl group preferably has a carbon number of 6 to 12. Examples of the arenediyl group include a phenylene group.

Specific examples of divalent hydrocarbon groups include methylene, ethylene, trimethylene, hexamethylene, heptamethylene, octamethylene, and dodecamethylene groups.

The hydrocarbon group which may contain a heteroatom in ^R23 and ^R24 includes a chain hydrocarbon group and a cyclic hydrocarbon group, and the chain hydrocarbon group is preferable.

Examples of the chain-like hydrocarbon group include a linear alkyl group and a branched alkyl group, with the linear alkyl group being preferred.
The carbon number of the linear alkyl group is preferably 1 to 20, more preferably 1 to 10, and further preferably 1 to 5. Examples of the linear alkyl group include a methyl group, an ethyl group, an n-propyl group, an n-butyl group, an n-hexyl group, an n-octyl group, an n-nonyl group, an n-decyl group, and an n-lauryl group.
The carbon number of the branched alkyl group is preferably 3 to 20, more preferably 3 to 10, and further preferably 3 to 5. Examples of the branched alkyl group include an isopropyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a 2-ethylhexyl group, a neopentyl group, and an isooctyl group.

Examples of the cyclic hydrocarbon group include a cyclic alkyl group and an aromatic group, and the cyclic alkyl group and the aromatic group may have a chain portion.
The number of carbon atoms in the cyclic alkyl group is preferably 4 to 18, more preferably 6 to 12, and even more preferably 6 to 10. Examples of the cyclic alkyl group include a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, and a cyclooctyl group.
The number of carbon atoms in the aromatic group is preferably 6 to 18, more preferably 6 to 12, and even more preferably 6 to 8. Examples of the aromatic group include a phenyl group, a tolyl group, a xylyl group, and a mesityl group.
Examples of the cyclic alkyl group having a chain portion and the chain portion of the aromatic group having a chain portion include alkylene groups having 1 to 12 carbon atoms, preferably alkylene groups having 1 to 6 carbon atoms, and more preferably alkylene groups having 1 to 3 carbon atoms.

The hydrocarbon group containing a heteroatom has a structure in which a carbon atom in the above-mentioned hydrocarbon group is replaced with a heteroatom. Examples of the heteroatom that may be contained in the hydrocarbon group include an oxygen atom.
Furthermore, a hydrogen atom in the hydrocarbon group may be substituted with a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom.

The phrase "R ²³ and R ²⁴ are bonded to each other to form a cyclic structure" means that R ²³ and R ²⁴ form a cyclic structure via a nitrogen atom. Examples of the cyclic structure include a 5- to 7-membered nitrogen-containing heterocycle or a condensed ring formed by condensing two of these. The nitrogen-containing heterocycle is preferably one that does not have aromaticity, and more preferably a saturated ring. Specific examples include structures represented by the following formulas (2-1), (2-2), and (2-3).

[In formulas (2-1), (2-2), and (2-3), R ²⁵ 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, multiple R ^25s may be the same or different.]

Specific examples of vinyl monomers that form the structural unit represented by formula (2) include dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, dimethylaminobutyl (meth)acrylate, diethylaminoethyl (meth)acrylate, diethylaminopropyl (meth)acrylate, diethylaminobutyl (meth)acrylate, ethylaminoethyl (meth)acrylate, ethylaminopropyl (meth)acrylate, ethylaminobutyl (meth)acrylate, propylaminoethyl (meth)acrylate, propylaminopropyl (meth)acrylate, propylaminobutyl (meth)acrylate, dimethylaminopropyl acid (meth)acrylamide, etc.

The difference (δ h1 - δ _h2 ) between the hydrogen bonding strength term (δ _h1 ) of the Hansen solubility parameter of the structural unit (b-1) and the hydrogen bonding strength term (δ _h2 ) of the Hansen solubility parameter of the structural unit ( _b -2) is preferably 0.5 ^{J 1/2} cm ^1/2 mol ^-1 or more, more preferably 2.5 ^J 1/2 cm ^1/2 mol ^-1 or more, even more preferably 5.0 ^{J 1/2} cm ^1/2 mol ^-1 or more, and is preferably 15.0 ^{J 1/2} cm ^1/2 mol ^-1 or less, more preferably 13.0 ^{J 1/2} cm ^1/2 mol ^-1 or less, even more preferably 10.0 ^{J 1/2} cm ^1/2 mol ^-1 or less, particularly preferably 8.0 J ^1/2 cm ^1/2 mol ^-1 or less. If the difference (δ _h1 - δ _h2 ) is 0.5 ^{J 1/2} ·cm ^1/2 ·mol ^-1 or more, it is believed that in addition to adsorption to the colorant, the effect of increasing affinity to the dispersion medium will be further improved, and if it is 15.0 J ^1/2 ·cm ^1/2 ·mol ^-1 or less, improved storage stability can be expected without inhibiting adsorption between the structural unit (b-2) of the block copolymer and the colorant.

In addition, when the B segment has a plurality of types of structural units (b-1) and/or structural units (b-2), the average value of each hydrogen bonding term is calculated, and the difference (δ _h1 - δ _h2 ) is calculated using the average value. The average value of the hydrogen bonding term is calculated by multiplying the hydrogen bonding term of each structural unit by the molar fraction of each structural unit and adding up the results. For example, when structural units (b-1) are contained as structural units (b-11) and (b-12), the average value of the hydrogen bonding term of the structural unit (b-1) is the sum of the product of the molar fraction of the structural unit (b-11) in all structural units (b-1) and the hydrogen bonding term of the structural unit (b-11), and the product of the molar fraction of the structural unit (b-12) in all structural units (b-1) and the hydrogen bonding term of the structural unit (b-12).

(Hansen Solubility Parameter)
Hansen solubility parameter (HSP) is a value used to predict the solubility of a substance, calculated by the method proposed by Hansen et al. Specifically, HSP is a value calculated by the following formula (Formula (1)). In Formula (1), δ represents the HSP of the polymer block. δ _d represents the London dispersion term of the HSP. δ _p represents the dipole-dipole term of the HSP. δ _h represents the hydrogen bond term of the HSP.
^δ2 = _δd2 ⁺ _δp2 ₊ ^δh2 ( ¹ )
The δ _d , δ _p and δ _h are values calculated from the molar attractive force multipliers (F _di , F _pi , E _hi ) and the molar volume V _i of the atomic group i constituting the structural unit of the polymer block according to the following formulas (formulas (2) to (4)).
δ _d =ΣF _di /ΣV _i (2)
δ _p = (ΣF _pi ² ) ^1/2 /ΣV _i (3)
δ _h = (ΣE _hi /ΣV _i ) ^1/2 (4)
Table 1 shows the molar attraction multipliers (F _di , F _pi , E _hi ) and molar volumes V _i of representative atomic groups.

The content of the structural unit (b-2) is preferably 5 mol% or more, more preferably 15 mol% or more, even more preferably 30 mol% or more, and is preferably 90 mol% or less, more preferably 85 mol% or less, even more preferably 80 mol% or less, out of 100 mol% of the structural units constituting the B segment. If the content of the structural unit (b-2) is within the above range, the adsorption ability to the colorant is further improved.

The content of the structural unit (b-2) is preferably 1 mol% or more, more preferably 50 mol% or more, and even more preferably 65 mol% or more, and is preferably less than 100 mol%, more preferably 99 mol% or less, and even more preferably 90 mol% or less, out of 100 mol% of the structural units constituting the B block. If the content of the structural unit (b-2) is within the above range, the adsorption ability with the colorant is further improved.

The molar ratio ((b-1)/(b-2)) of the structural unit (b-1) to the structural unit (b-2) in the B segment is preferably 5/95 or more, more preferably 10/90 or more, even more preferably 20/80 or more, and is preferably 95/5 or less, more preferably 80/20 or less, even more preferably 70/30 or less. If the molar ratio ((b-1)/(b-2)) is within the above range, it is believed that adsorption to the colorant and affinity to the dispersion medium will work more effectively.

In the 100 mol% structural units constituting the B segment, the total content ((b-1)+(b-2)) of the structural units (b-1) and (b-2) is preferably 30 mol% or more, more preferably 40 mol% or more, and even more preferably 50 mol% or more, and is preferably 100 mol% or less. If the total content ((b-1)+(b-2)) is within the above range, it can be expected that the dispersibility of the colorant will be further improved.

(Structural Unit (b-3) Having a Salt of a Basic Group)
The B segment may contain a structural unit (b-3) having a salt of a basic group in addition to the structural unit (b-1) and the structural unit (b-2). By containing the structural unit (b-3), strong adsorptivity to the colorant surface can be maintained for a long period of time, and storage stability is further improved. The structural unit (b-3) may be of only one type, or of two or more types.

Examples of the salt of the basic group include inorganic salts such as halide salts (F, Cl, Br, I, etc.) and sulfate salts of the basic group; and sulfonates, sulfates, phosphates, or carboxylates of organic compounds. The salt of the basic group is preferably an amino group salt in view of availability of raw materials and ease of synthesis. In this specification, the salt of the amino group also includes salts (e.g., halides) of quaternary ammonium groups (-NR ^c R ^d R ^e (R ^c , R ^d and R ^e each independently represent a chain or cyclic hydrocarbon group. Two or more of R ^c , R ^d and R ^e may be bonded to each other to form a cyclic structure.)). The structural unit (b-3) having a salt of a basic group may be a salt formed by part of the basic group of the structural unit (b-2) having a basic group.

The structural unit (b-3) is preferably a structural unit represented by formula (3).

[In formula (3), R ³¹ represents a hydrogen atom or a methyl group. A ³¹ represents an ester group, an amide group, or a single bond. R ³² represents a divalent hydrocarbon group. R ³³ , R ³⁴ , and R ³⁵ each independently represent a hydrocarbon group which may contain a heteroatom. Two or more of R ³³ , R ³⁴ , and R ³⁵ may be bonded to each other to form a cyclic structure. X ⁻ represents a counter ion.]

The A ³¹ represents an ester group (-CO-O-), an amide group (-CO-NH-) or a single bond, and is preferably an ester group or an amide group in terms of affinity to the dispersion medium and alkaline developability. The bonding direction of the ester group or the amide group is not particularly limited. Examples of the bonding form of the ester group include C-CO-O-R ³² or C-O-CO-R ³² , and C-CO-O-R ³² is preferred. Examples of the bonding form of the amide group include C-CO-NH-R ³² or C-NH-CO-R ³² , and C-CO-NH-R ³² is preferred.

The divalent hydrocarbon group represented by R ³² includes a linear alkylene group, a branched alkylene group, a cyclic alkylene group, an alkenylene group, an arenediyl group, etc., and the linear alkylene group is preferred.
The linear alkylene group preferably has a carbon number of 1 to 10, and more preferably has a carbon number of 1 to 5. Examples of the linear alkylene group include a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, and a pentamethylene group.
The branched alkylene group preferably has a carbon number of 3 to 10. Examples of the branched alkylene group include a propylene group, a propylidene group, a 1,2-butanediyl group, and a 1,3-butanediyl group.
The cyclic alkylene group preferably has a carbon number of 6 to 12. Examples of the cyclic alkylene group include a cyclopropylene group, a cyclobutylene group, a cyclopentylene group, and a cyclohexylene group.
The alkenylene group preferably has a carbon number of 2 to 10. Examples of the alkenylene group include an ethenylene group, a 2-propenylene group, a 2-butenylene group, and a 3-butenylene group.
The arenediyl group preferably has a carbon number of 6 to 12. Examples of the arenediyl group include a phenylene group.

Specific examples of divalent hydrocarbon groups include methylene, ethylene, n-propylene, n-hexylene, n-heptylene, n-octylene, and n-dodecylene groups.

The hydrocarbon group which may contain a heteroatom in R ³³ , R ³⁴ and R ³⁵ includes a chain hydrocarbon group and a cyclic hydrocarbon group.

It is preferable that R ³³ , R ³⁴ and R ³⁵ are a combination of two straight-chain alkyl groups and one aromatic group, or all three are straight-chain alkyl groups.

The expression "R ³³ , R ³⁴ and R ³⁵ are bonded together to form a cyclic structure" means that two or more of R ³³ , R ³⁴ and R ³⁵ form a cyclic structure via a nitrogen atom. Examples of the cyclic structure include a 5- to 7-membered nitrogen-containing heterocycle or a condensed ring formed by condensing two of these. The nitrogen-containing heterocycle is preferably one that does not have aromaticity, and more preferably a saturated ring. Specific examples include structures represented by the following formulae (3-1), (3-2) and (3-3).

[In formulas (3-1), (3-2) and (3-3), R ³⁶ is R ^33. R ³⁷ 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 multiple R ³⁶ 's may be the same or different.]

X ⁻ includes a halogen anion, a carboxylate anion, a sulfate anion, a sulfonate anion, a phosphate anion, a nitroxide anion, and the like.

Examples of the halogen anion include a fluoro anion, a chloro anion, a bromo anion, and an iodo anion.
Examples of the carboxylate anion include alkyl carboxylate anions such as acetate anion and propionate anion; and aromatic carboxylate anions such as benzoate anion.
Examples of the sulfate anion include alkyl sulfate anions such as methyl sulfate anion and ethyl sulfate anion; and aromatic sulfate anions such as phenyl sulfate anion and benzyl sulfate anion.
Examples of the sulfonate anion include alkylsulfonate anions such as methanesulfonate anion and ethanesulfonate anion; and aromatic sulfonate anions such as benzenesulfonate anion and toluenesulfonate anion.
Examples of the phosphate anion include alkyl phosphate anions such as methylphosphonate anion and ethylphosphonate anion; and aromatic phosphate anions such as phenylphosphonate anion and benzylphosphonate anion.

Specific examples of vinyl monomers that form the structural unit represented by formula (3) include (meth)acryloyloxyethyl trimethyl ammonium chloride, (meth)acryloyloxypropyl trimethyl ammonium chloride, (meth)acryloyloxybutyl trimethyl ammonium chloride, (meth)acryloyloxyethyl benzyl dimethyl ammonium chloride, (meth)acryloyloxypropyl benzyl dimethyl ammonium chloride, (meth)acryloyloxybutyl benzyl dimethyl ammonium chloride, (meth)acryloyloxyethyl benzyl acryloyloxypropyl benzyl diethyl ammonium chloride, (meth)acryloyloxybutyl benzyl diethyl ammonium chloride, (meth)acryloyloxyethyl benzyl diethyl ammonium bromide, (meth)acryloyloxypropyl benzyl diethyl ammonium bromide, (meth)acryloyloxybutyl benzyl diethyl ammonium bromide, (meth)acryloyloxyethyl benzyl diethyl ammonium iodide, (meth)acryloyloxypropyl benzyl diethyl ammonium Iodide, (meth)acryloyloxybutylbenzyl diethylammonium iodide, (meth)acryloyloxyethylbenzyl diethylammonium fluoride, (meth)acryloyloxypropylbenzyl diethylammonium fluoride, (meth)acryloyloxybutylbenzyl diethylammonium fluoride, (meth)acryloyloxyethyltrimethylammonium methylsulfate, (meth)acryloyloxypropyltrimethylammonium methylsulfate, (meth)acryloyloxybutyltrimethylammonium methylsulfate ester, (meth)acryloyloxyethyl dimethylethyl ammonium ethyl sulfate, (meth)acryloyloxypropyl dimethylethyl ammonium ethyl sulfate, (meth)acryloyloxybutyl dimethylethyl ammonium ethyl sulfate, (meth)acryloyloxyethyl trimethyl ammonium toluene-4-sulfonate, (meth)acryloyloxypropyl trimethyl ammonium toluene-4-sulfonate, (meth)acryloyloxybutyl trimethyl ammonium toluene-4-sulfonate, etc.

When the structural unit (b-3) is contained, its content is preferably 5 mol% or more, more preferably 30 mol% or more, even more preferably 45 mol% or more, and preferably 90 mol% or less, more preferably 80 mol% or less, even more preferably 70 mol% or less, out of 100 mol% of the structural units constituting the B segment. If the content of the structural unit (b-3) is within the above range, strong adsorption to the colorant surface can be maintained for a long period of time, and storage stability is further improved.

When the structural unit (b-3) is contained, the total content of the structural units (b-2) and (b-3) ((b-2) + (b-3)) in 100 mol% of the structural units constituting the B segment is preferably 5 mol% or more, more preferably 30 mol% or more, even more preferably 45 mol% or more, and is preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 70 mol% or less. If the total content ((b-2) + (b-3)) is within the above range, it is believed that strong adsorption to the colorant surface can be maintained for a long period of time, and storage stability is further improved.

When the structural unit (b-3) is contained, the molar ratio ((b-1)/{(b-2)+(b-3)}) of the structural unit (b-1) to the total amount of the structural unit (b-2) and the structural unit (b-3) in the B segment is preferably 5/95 or more, more preferably 10/90 or more, even more preferably 20/80 or more, and is preferably 95/5 or less, more preferably 80/20 or less, even more preferably 60/40 or less. If the molar ratio ((b-1)/{(b-2)+(b-3)}) is within the above range, it is believed that strong adsorption to the colorant surface can be maintained for a long period of time, and storage stability is further improved.

The B segment may contain other structural units in addition to the structural units (b-1), (b-2), and (b-3). Specific examples of vinyl monomers that can form other structural units of the B segment include the same monomers as those exemplified as specific examples of monomers that can form structural units of the A block.

If other structural units are contained, the content of the other structural units in 100 mol% of the structural units constituting the B segment is preferably 90 mol% or less, more preferably 70 mol% or less, and even more preferably 20 mol% or less.

(Block Copolymer)
The structure of the block copolymer is preferably a linear block copolymer. The linear block copolymer may have any structure (sequence), but from the viewpoint of the physical properties of the linear block copolymer or the physical properties of the composition, when the A segment is expressed as A and the B segment is expressed as B, it is preferable that the copolymer has at least one structure selected from the group consisting of (A-B) _m type, (A-B) _m -A type, and (B-A) _m -B type (m is an integer of 1 or more, for example, an integer of 1 to 3). Among these, from the viewpoint of the handling property during processing and the physical properties of the composition, it is preferable to be an A-B type block copolymer. By forming an A-B type block copolymer, it is considered that the structural unit of the A segment and the structural unit (b-2) of the B segment are localized and can efficiently act favorably with the colorant, the dispersion medium, and the binder resin. The block copolymer may have other blocks other than the A segment and the B segment. As the block copolymer, a diblock copolymer composed of one A block and one B block, and a triblock copolymer composed of one A block and two B blocks are preferable.

In all structural units constituting the block copolymer, the content of the total number of moles of structural units constituting the A segment is preferably 30 mol% or more, more preferably 35 mol% or more, even more preferably 40 mol% or more, and is preferably 75 mol% or less, more preferably 70 mol% or less, even more preferably 65 mol% or less, and particularly preferably 60 mol% or less.

In all structural units constituting the block copolymer, the content of the total number of moles of structural units constituting the B segment is preferably 25 mol% or more, more preferably 30 mol% or more, even more preferably 35 mol% or more, and particularly preferably 40 mol% or more, and is preferably 70 mol% or less, more preferably 65 mol% or less, and even more preferably 60 mol% or less.

In the block copolymer, the molar ratio (A segment/B segment) of the total molar amount of the structural units constituting the A segment to the total molar amount of the structural units constituting the B segment is preferably 30/70 or more, more preferably 35/65 or more, even more preferably 40/60 or more, and is preferably 75/25 or less, more preferably 70/30 or less, even more preferably 65/35 or less, and particularly preferably 60/40 or less. If the molar ratio (A segment/B segment) is 30/70 or more, aggregation with the colorant is prevented due to the steric repulsion of the A segment, improving storage stability, and if it is 75/25 or less, strong adsorption of the basic group to the colorant surface can be maintained for a long period of time, further improving storage stability.

The weight average molecular weight (Mw) of the block copolymer is preferably 5,000 or more, more preferably 8,000 or more, even more preferably 10,000 or more, and is preferably 40,000 or less, more preferably 30,000 or less, even more preferably 20,000 or less. If the weight average molecular weight is within the above range, the dispersion performance when used as a dispersant will be better. The molecular weight of the block copolymer is measured by gel permeation chromatography (hereinafter referred to as "GPC") method.

The molecular weight distribution (Mw/Mn) of the block copolymer is preferably less than 3.0, more preferably 2.0 or less, and even more preferably 1.7 or less. If the molecular weight distribution (Mw/Mn) is less than 3.0, the dispersion performance when used as a dispersant will be better. The molecular weight distribution is calculated by (weight average molecular weight (Mw) of the block copolymer) / (number average molecular weight (Mn) of the block copolymer). The smaller the value of the molecular weight distribution, the narrower the molecular weight distribution width, resulting in a copolymer with a uniform molecular weight, and when the value is 1.0, the width of the molecular weight distribution is the narrowest. In other words, the lower limit of the molecular weight distribution is 1.0.

The amine value of the block copolymer is preferably 10 mgKOH/g or more, more preferably 25 mgKOH/g or more, and even more preferably 40 mgKOH/g or more, from the viewpoint of adsorption to the colorant and dispersibility of the colorant, and is preferably 150 mgKOH/g or less, more preferably 120 mgKOH/g or less, and even more preferably 100 mgKOH/g or less.

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 setting the acid value within this range, the block copolymer can act favorably with the binder resin (alkali-soluble resin) without impairing its affinity with the colorant.

(Method for Producing Block Copolymer)
Examples of the method for producing the block copolymer include a method of first producing an A segment by a polymerization reaction of a vinyl monomer, and polymerizing a monomer of a B segment to the A segment; a method of first producing a B segment, and polymerizing a monomer of an A segment to the B segment; a method of separately producing an A segment and a B segment, and then coupling the A segment and the B segment; a method of first producing an A segment, polymerizing a monomer composition containing a vinyl monomer capable of forming structural units (b-1) and structural units (b-2) in the B segment, and quaternizing a part of the tertiary amine structure of the structural unit (b-2) in the obtained polymer; a method of polymerizing a monomer composition containing a vinyl monomer capable of forming structural units (b-1) and structural units (b-2), polymerizing a monomer of the A segment to this polymer, and quaternizing a part of the tertiary amine structure of the structural unit (b-2) in the obtained polymer; a method of separately producing an A segment and a segment having structural units (b-1) and structural units (b-2), coupling these segments, and then quaternizing a part of the tertiary amine structure of the structural unit (b-2) in the obtained polymer.

Although the polymerization method is not particularly limited, living polymerization is preferred. That is, the block copolymer is preferably one polymerized by living polymerization. Among the four elementary reactions in chain polymerization, namely, initiation reaction, propagation reaction, termination reaction, and chain transfer reaction, living polymerization is preferred in that termination reaction and chain transfer reaction are unlikely to occur, and the vinyl monomer reacts and the polymer chain grows without deactivating the reaction point (polymerization growth end), making it easy to precisely control the molecular weight distribution and produce a polymer with a uniform composition. Living polymerization methods include living radical polymerization, living anionic polymerization, and living cationic polymerization. Among these, living radical polymerization is preferred from the viewpoint of the simplicity of polymerization. Living radical polymerization is also preferred in that it is easy to precisely control the molecular weight distribution and produce a polymer with a uniform composition while maintaining the simplicity and versatility of free radical polymerization (conventional radical polymerization).

Living radical polymerization methods include a method using a compound capable of generating nitroxide radicals (nitroxide method; NMP method) depending on the method of stabilizing the polymer growth end; a method using a metal complex such as copper or ruthenium to polymerize a halogenated compound as a polymerization initiator compound in a living manner from the polymerization initiator compound (ATRP method); a method using a dithiocarboxylic acid ester or a xanthate compound (RAFT method); a method using an organic tellurium compound (TERP method); a method using an organic iodine compound (ITP method); a method using an iodine compound as a polymerization initiator compound and an organic compound such as a phosphorus compound, a nitrogen compound, an oxygen compound, or a hydrocarbon as a catalyst (reversible transfer catalyst polymerization; RTCP method, reversible catalyst-mediated polymerization; RCMP method), etc. Among these methods, the TERP method is preferable from the viewpoint of the diversity of monomers that can be used, molecular weight control in the polymer region, uniform composition, or coloring.

The TERP method is a method of polymerizing a radically polymerizable compound (vinyl monomer) using an organic tellurium compound as a chain transfer agent, and is described, for example, in WO 2004/14848, WO 2004/14962, WO 2004/072126, WO 2004/096870, and WO 2020/116144.

Specific polymerization methods of the TERP method include the following (a) to (d).
(a) A method of polymerizing a vinyl monomer using an organotellurium compound represented by formula (6):
(b) A method of polymerizing a vinyl monomer using a mixture of an organotellurium compound represented by formula (6) and an azo-based polymerization initiator.
(c) A method of polymerizing a vinyl monomer using a mixture of an organotellurium compound represented by formula (6) and an organoditelluride compound represented by formula (7).
(d) A method of polymerizing a vinyl monomer using a mixture of an organotellurium compound represented by formula (6), an azo-based polymerization initiator, and an organoditelluride compound represented by formula (7).

In formula (6), R ⁶¹ represents an alkyl group having 1 to 8 carbon atoms, an aryl group, or an aromatic heterocyclic group. R ⁶² and R ⁶³ each independently represent a hydrogen atom or an alkyl group having 1 to 8 carbon atoms. R ⁶⁴ 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 amido group, an oxycarbonyl group, a cyano group, an allyl group, or a propargyl group.
In formula (7), R ⁶¹ represents an alkyl group having 1 to 8 carbon atoms, an aryl group, or an aromatic heterocyclic group.

Specific examples of the organic tellurium compound represented by formula (6) include ethyl 2-methyl-2-n-butyltellanyl-propionate, ethyl 2-n-butyltellanyl-propionate, (2-hydroxyethyl) 2-methyl-methyltellanyl-propionate, and the organic tellurium compounds described in WO 2004/14848, WO 2004/14962, WO 2004/072126, WO 2004/096870, and WO 2020/116144. Specific examples of the organic ditelluride compound represented by formula (7) include dimethyl ditelluride, dibutyl ditelluride, and the like. The azo polymerization initiator can be any azo polymerization initiator used in normal radical polymerization without any particular restrictions, and examples thereof include 2,2'-azobis(isobutyronitrile) (AIBN), 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), 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile) (V-70), 2,2'-azobis(N-butyl-2-methylpropionamide) (VAm-110), and the like.

In the polymerization process, a vinyl monomer and an organic tellurium compound of formula (6) are mixed in a vessel purged with an inert gas, and for the purpose of promoting the reaction and controlling the molecular weight and molecular weight distribution depending on the type of vinyl monomer, an azo polymerization initiator and/or an organic ditelluride compound of formula (7) are further mixed. Examples of the inert gas include nitrogen, argon, and helium. Argon and nitrogen are preferable. The amounts of the vinyl monomer used in (a), (b), (c), and (d) above may be adjusted appropriately depending on the physical properties of the desired copolymer.

The polymerization reaction can be carried out without a solvent, but it can also be carried out by using an aprotic or protic solvent that is generally used in radical polymerization, and stirring the mixture. Examples of aprotic solvents that can be used include acetonitrile, methyl ethyl ketone, anisole, benzene, toluene, propylene glycol monomethyl ether acetate, ethyl acetate, tetrahydrofuran (THF), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-2-pyrrolidone (NMP), acetone, dioxane, chloroform, and carbon tetrachloride. Examples of protic solvents include water, methanol, ethanol, isopropanol, n-butanol, ethyl cellosolve, butyl cellosolve, 1-methoxy-2-propanol, hexafluoroisopropanol, and diacetone alcohol. The solvents may be used alone or in combination of two or more. The amount of solvent used may be adjusted as appropriate, and is preferably 0.01 ml to 50 ml per 1 g of vinyl monomer, for example. In addition to the solvent, a surfactant and/or a dispersant may also be used in the polymerization reaction.

The reaction temperature and reaction time may be adjusted as appropriate depending on the molecular weight or molecular weight distribution of the resulting copolymer, but typically the reaction is carried out at 0°C to 150°C and for 1 minute to 100 hours with stirring. The pressure is typically normal, but it may be increased or decreased. The polymerization reaction may also be carried out by irradiation with light. After the polymerization reaction is complete, the solvent used and residual vinyl monomers are removed from the resulting reaction mixture by standard separation and purification means, allowing the desired copolymer to be separated.

The growing end of the copolymer obtained by the polymerization reaction is in the form of -TeR ⁶¹ (wherein R ⁶¹ is the same as above) derived from the tellurium compound, and is deactivated by operation in air after the polymerization reaction is completed, but the tellurium atom may remain. Since a copolymer with tellurium atoms remaining at the end is colored or has poor thermal stability, it is preferable to remove the tellurium atoms. Methods for removing tellurium atoms include a radical reduction method; a method of adsorption with activated carbon or the like; a method of adsorbing metal with an ion exchange resin or the like, and these methods can also be used in combination. The other end (the end opposite to the growing end) of the copolymer obtained by the polymerization reaction is in the form of -CR ⁶² R ⁶³ R ⁶⁴ (wherein R ⁶² , R ⁶³ and R ⁶⁴ are the same as R ⁶² , R ⁶³ and R ⁶⁴ in formula (6)) derived from the tellurium compound. Therefore, the copolymer obtained by the TERP method does not have a substituent containing a sulfur atom at the end.

When tertiary amino groups of structural units having basic groups are quaternized, examples of the quaternizing agent include alkyl halides such as methyl chloride, ethyl chloride, methyl bromide, and methyl iodide; aralkyl halides such as benzyl chloride, benzyl bromide, and benzyl iodide; diaryl sulfates such as diphenyl sulfate; dialkyl sulfates such as dimethyl sulfate, diethyl sulfate, and di-n-propyl sulfate; and aromatic alkyl sulfonates such as methyl p-toluenesulfonate and ethyl p-toluenesulfonate. Among these, preferred are aralkyl halides such as benzyl chloride, benzyl bromide, and benzyl iodide, dialkyl sulfates such as dimethyl sulfate, diethyl sulfate, and di-n-propyl sulfate, and aromatic alkyl sulfonates such as methyl p-toluenesulfonate and ethyl p-toluenesulfonate, and more preferred are benzyl chloride, dimethyl sulfate, and methyl p-toluenesulfonate. An alkyl group or aralkyl group derived from the quaternizing agent is introduced into the structure after quaternization.

As a method for quaternizing some of the tertiary amine structures of structural units having a basic group in a polymer, a method of contacting the polymer with a quaternizing agent can be mentioned. Specifically, a method of polymerizing a monomer composition containing a vinyl monomer capable of forming a structural unit having a basic group, adding a quaternizing agent to the reaction liquid, and stirring the reaction liquid can be mentioned. The temperature of the reaction liquid to which the quaternizing agent is added is preferably 55°C to 65°C, and the stirring time is preferably 5 hours to 20 hours.

<Dispersant>
The dispersant of the present invention contains the block copolymer as a main component (50% by mass or more). The block copolymer exerts an effect of enhancing the dispersibility of the colorant by adsorbing the basic group in the structure (B segment) to the colorant. In other words, the dispersant of the present invention is a component that disperses the colorant well by this effect, so there is no particular limitation on the type of colorant to be dispersed.
The dispersant of the present invention has high dispersibility for coloring materials and can be suitably used as a dispersant for colored compositions for color filters.
In addition, since the dispersant of the present invention has high dispersibility for colorants, it can also be used in inkjet inks, printing inks, writing instrument inks, paints, etc. By appropriately changing the composition of the block copolymer, it can be used not only in coloring compositions using organic solvents, but also in coloring compositions using aqueous solvents.

The content of the block copolymer in the dispersant is 50% by mass or more, preferably 70% by mass or more, and more preferably 90% by mass or more. The dispersant may be composed of only the block copolymer.

<Coloring composition>
The coloring composition of the present invention contains the dispersant, a colorant, and a dispersion medium. The coloring composition of the present invention has high dispersibility of the colorant and can be suitably used as a coloring composition for color filters.

(Coloring material)
The type and particle size of the coloring material may be appropriately selected according to the application, and are not particularly limited. The 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 mainly composed of an organic compound is particularly preferred. Examples of the pigment include red pigments, yellow pigments, orange pigments, blue pigments, green pigments, purple pigments, and other pigments of various colors. The structure of the pigment may include azo pigments such as monoazo pigments, diazo pigments, and condensed diazo pigments, diketopyrrolopyrrole pigments, phthalocyanine pigments, isoindolinone pigments, isoindoline pigments, quinacridone pigments, indigo pigments, thioindigo pigments, quinophthalone pigments, dioxazine pigments, anthraquinone pigments, perylene pigments, and polycyclic pigments such as perinone pigments. The pigment contained in the coloring composition may be only one type or multiple types.

Specific examples of pigments include red pigments such as 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, 168, 177, 178, 179, 187, 200, 202, 208, 210, 215, 224, 254, 255, 264, and 291; C.I. Yellow pigments such as 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; orange pigments such as C.I. Pigment Orange 36, 38, 43; blue pigments such as C.I. Pigment Blue 15, 15:2, 15:3, 15:4, 15:6, 16, 22, 60; Examples of the pigments include green pigments such as C.I. Pigment Green 7, 36, 58, 59, 62, 63, aluminum phthalocyanine, polyhalogenated aluminum phthalocyanine, aluminum phthalocyanine hydroxide, diphenoxyphosphinyloxyaluminum phthalocyanine, diphenylphosphinyloxyaluminum phthalocyanine, polyhalogenated diphenoxyphosphinyloxyaluminum phthalocyanine, polyhalogenated diphenylphosphinyloxyaluminum phthalocyanine, and the like; and purple pigments such as C.I. Pigment Violet 23, 32, 50, and the like. Among these, the pigments include C.I. Pigment Red 177, C.I. Pigment Red 254, C.I. Pigment Red 255, C.I. Pigment Red 264, C.I. Pigment Red 291, C. I. Pigment Blue 15, C. I. Pigment Blue 15:2, C.I. I. Pigment Blue 15:3, C.I. I. Pigment Blue 15:4, C.I. I. Pigment Blue 15:6, C.I. I. Pigment Blue 16, C. I. Pigment Green 7, C. I. Pigment Green 36, C. I. Pigment Green 58, C. I. Pigment Green 59, C. I. Pigment Green 62, Pigment Green 63, etc. are preferred.

The colorant may contain a dye derivative as a dispersing aid. The dye derivative preferably contains an acidic dye derivative having an acidic group in order to form an ionic bond with a basic group in the block copolymer contained in the dispersant and adsorb it. This dye derivative is one in which an acidic group has been introduced into the dye skeleton. The dye skeleton is preferably the same or similar to the colorant constituting the coloring composition, or the same or similar to the compound that is the raw material of the colorant. Specific examples of the dye skeleton include an azo dye skeleton, a phthalocyanine dye skeleton, an anthraquinone dye skeleton, a triazine dye skeleton, an acridine dye skeleton, and a perylene dye skeleton. The acidic group introduced into the dye skeleton is preferably a carboxy group, a phosphoric acid group, or a sulfonic acid group. For convenience of synthesis and strength of acidity, a sulfonic acid group is preferred. The acidic group may be directly bonded to the dye skeleton, or may be bonded to the dye skeleton via a hydrocarbon group such as an alkyl group or an aryl group; an ester, an ether, a sulfonamide, or a urethane bond.
The amount of the dye derivative used is not particularly limited, but is preferably, for example, 4 to 17 parts by weight per 100 parts by weight of the colorant.

The upper limit of the colorant content in the coloring composition is usually 80 mass %, preferably 70 mass %, and more preferably 60 mass %, based on the total solid content of the coloring composition, from the viewpoint of brightness. The lower limit of the colorant content in the coloring composition is usually 10 mass %, preferably 20 mass %, and more preferably 30 mass %, based on the total solid content of the coloring composition. Here, the solid content refers to components other than the dispersion medium described below.

The content of the dispersant relative to the colorant in the coloring composition is preferably 5 parts by mass to 200 parts by mass, more preferably 10 parts by mass to 100 parts by mass, and even more preferably 10 parts by mass to 80 parts by mass, relative to 100 parts by mass of the colorant. If the content of the dispersant is within the above range, the viscosity of the coloring composition will be good.

(Dispersion Medium)
The dispersion medium used in the present invention can be appropriately selected and used as long as it disperses or dissolves other components constituting the coloring composition, does not react with these components, and has moderate volatility. For example, conventionally known organic solvents can be used, for example, 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, methoxymethyl pentanol, dipropylene glycol monoethyl ether, dipropylene glycol monomethyl ether, 3-methyl-3-methoxybutanol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tripropylene glycol methyl ether and other glycol monoalkyl ethers; ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, Glycol dialkyl ethers such as diethylene glycol dipropyl ether, diethylene glycol dibutyl ether, and dipropylene glycol dimethyl ether; glycol alkyl ether acetates such as 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, and 3-methyl-3-methoxybutyl acetate; ethylene glycol diacetate glycol diacetates such as 1,3-butylene glycol diacetate and 1,6-hexanol diacetate; alkyl acetates such as cyclohexanol acetate; ethers such as amyl ether, propyl ether, diethyl ether, dipropyl ether, diisopropyl ether, butyl ether, diamyl ether, ethyl isobutyl ether and dihexyl ether; acetone, methyl ethyl ketone, methyl amyl ketone, methyl isopropyl ketone, methyl isoamyl ketone, diisopropyl ketone, diisobutyl ketone, methyl isopropyl ether, diisobutyl ketone, methyl ethyl ketone, diisobutyl ketone, methyl ethyl ketone, diisopropyl ether ... Ketones such as butyl ketone, cyclohexanone, ethyl amyl ketone, methyl butyl ketone, methyl hexyl ketone, methyl nonyl ketone, and methoxymethyl pentanone; monohydric or polyhydric alcohols such as ethanol, propanol, butanol, hexanol, cyclohexanol, ethylene glycol, propylene glycol, butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, methoxypropanol, methoxymethyl pentanol, glycerin, and benzyl alcohol; n-pentane, n-octane, and diisobutylene. aliphatic hydrocarbons such as n-hexane, hexene, isoprene, dipentene, and dodecane; alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, methylcyclohexene, and bicyclohexyl; 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 caprylate, butyl stearate, Examples of the organic solvent include chain or cyclic esters such as ethyl benzoate, methyl 3-ethoxypropionate, 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 amyl chloride; ether ketones such as methoxymethylpentanone; and nitriles such as acetonitrile and benzonitrile. From the viewpoints of dispersibility of colorants, solubility of dispersants, and coatability of the coloring composition, the organic solvent is preferably glycol alkyl ether acetates, glycol monoalkyl ethers, and monohydric or polyhydric alcohols. The dispersion medium contained in the coloring composition may be one type only, or may be a plurality of types.

When forming pixels of a color filter by photolithography, the boiling point of the dispersion medium is preferably 100°C to 200°C (under a pressure condition of 1013.25 hPa. The same applies to all boiling points below), and more preferably 120°C to 170°C. Among the above dispersion media, glycol alkyl ether acetates are preferred because they have a good balance of application properties, surface tension, etc., and the solubility of the components in the coloring composition is relatively high. Glycol alkyl ether acetates may be used alone or in combination with other dispersion media. It is also preferable to use a dispersion medium having a boiling point of 150°C or higher in combination. By using a dispersion medium with a high boiling point in combination, the destruction of the interrelationships of the coloring composition due to the rapid drying of the coloring composition can be suppressed. The dispersion medium having a boiling point of 150°C or higher may be a glycol alkyl ether acetate.

The content of the dispersion medium in the coloring composition is not particularly limited and can be adjusted as appropriate. The upper limit of the content of the dispersion medium in the coloring composition is usually 99% by mass. The lower limit of the content of the dispersion medium in the coloring composition is usually 70% by mass, preferably 80% by mass, taking into account the viscosity suitable for application of the coloring composition. The above dispersion medium can be used as a solvent for dissolving and removing precipitates formed from the coloring composition.

(Binder resin)
The coloring composition may contain a binder resin (excluding the block copolymer). Examples of the binder resin include an alkali-soluble resin, a polymerizable compound (polymerizable resin, a monomer having one polymerizable unsaturated bond in the molecule, a monomer having two or more polymerizable unsaturated bonds in the molecule, an oligomer, etc.), a thermosetting resin, a thermoplastic resin, etc. These can be used alone or in a mixture of two or more kinds. Among these, an alkali-soluble resin and/or a polymerizable compound is preferable.

The content of the binder resin in the coloring composition is the total amount of the binder resin used, and is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 5% by mass or more, of the total solid content of the coloring composition, and is preferably 70% by mass or less, more preferably 60% by mass or less, and even more preferably 50% by mass or less.

(Alkali-soluble resin)
The alkali-soluble resin is not particularly limited as long as it acts as a binder for a colorant and is soluble in a developer, preferably an alkaline developer, used in the development process when producing a color filter. However, it is preferable that the alkali-soluble resin is a resin having an acidic group such as a carboxy group or a phenolic hydroxy group.

Examples of the alkali-soluble resin include a resin obtained by adding an unsaturated monobasic acid to at least a portion of the epoxy groups in a copolymer of an epoxy group-containing (meth)acrylate and another radically polymerizable monomer, or a resin obtained by adding a polybasic acid anhydride to at least a portion of the hydroxyl groups produced by the addition reaction; a linear resin containing a carboxy group in the main chain; a resin in which an epoxy group-containing unsaturated compound is added to the carboxy group portion of a carboxy group-containing resin; a (meth)acrylic resin; an epoxy (meth)acrylate resin having a carboxy group, and the like. These can be used alone or in a mixture of two or more kinds.

Preferred examples of the alkali-soluble resin include random copolymers containing structural units derived from a carboxyl group-containing vinyl monomer, structural units derived from a (meth)acrylate, and styrene, synthetic resins in which a (meth)acrylic group has been introduced into an epoxy resin, and random copolymers containing structural units derived from a carboxyl group-containing vinyl monomer and structural units derived from a (meth)acrylate. Preferred examples of the carboxyl group-containing vinyl monomer include (meth)acrylic acid. Examples of the (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, benzyl (meth)acrylate, phenoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, adamantyl (meth)acrylate, tricyclodecanyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, hydroxypropyl (meth)acrylate, glycerol mono(meth)acrylate, glycidyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, and tetrahydrofurfuryl (meth)acrylate.

The alkali-soluble resin preferably has a total content of structural units derived from carboxyl group-containing vinyl monomers and structural units derived from (meth)acrylates of 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more. The alkali-soluble resin preferably has a total content of structures derived from carboxyl group-containing vinyl monomers of 5% by mass or more, more preferably 10% by mass or more, and even more preferably 20% by mass or more, and is preferably 90% by mass or less, and more preferably 70% by mass or less.

Among the above-mentioned alkali-soluble resins, random copolymers of carboxy-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 viewpoint of the affinity between the alkali-soluble resin and the colorant, the alkali-soluble resin is particularly preferably a random copolymer of (meth)acrylic acid and benzyl (meth)acrylate. In the copolymer of a carboxy-containing vinyl monomer and a (meth)acrylate, the content of (meth)acrylic acid is usually 5% by mass to 90% by mass, preferably 10% by mass to 70% by mass, and more preferably 20% by mass to 70% by mass, of the total monomer components. The polymerization method for these random copolymers is not particularly limited, but living radical polymerization is preferred from the viewpoint of alkali solubility.

The alkali-soluble resin may have a radically polymerizable carbon-carbon double bond in the side chain. By having a double bond in the side chain, the photocurability of the coloring composition according to the present invention is increased, and therefore the resolution and adhesion can be further improved. Examples of a method for introducing a radically polymerizable carbon-carbon double bond in the side chain include a method of reacting a compound such as glycidyl (meth)acrylate, (3,4-epoxycyclohexyl)methyl (meth)acrylate, or o-(or m-, or p-)vinylbenzyl glycidyl ether with the acidic group of the binder resin.

The Mw of the alkali-soluble 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 alkali-soluble resin is 3,000 or more, the heat resistance, film strength, etc. of the colored layer formed from the colored composition will be good, and if the Mw is 100,000 or less, the alkaline developability of this coating film will be even better.

The acid value of the alkali-soluble 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 alkali-soluble resin is 20 mgKOH/g or more, the alkali developability becomes even better when the coloring composition is used as a colored layer, and if it is 170 mgKOH/g or less, the heat resistance becomes good.

The coloring composition may contain only one type of alkali-soluble resin, or multiple types. In the coloring composition, the content of the alkali-soluble resin is preferably 5 parts by mass to 200 parts by mass, more preferably 10 parts by mass to 100 parts by mass, and even more preferably 20 parts by mass to 80 parts by mass, per 100 parts by mass of the coloring material.

(Polymerizable compound)
Examples of the polymerizable compound include polymerizable resins (e.g., resins in which a crosslinkable group such as a (meth)acrylic compound or cinnamic acid is introduced into a linear polymer having a reactive substituent such as a hydroxy group, a carboxy group, or an amino group via an isocyanate group, an aldehyde group, or an epoxy group), compounds having one polymerizable unsaturated bond in the molecule (e.g., monofunctional (meth)acrylic monomers (alkyl (meth)acrylates, aralkyl (meth)acrylates, etc.)), compounds having two or more polymerizable unsaturated bonds in the molecule (e.g., polyfunctional (meth)acrylic monomers (di(meth)acrylates of dihydric alcohols, poly(meth)acrylates of trihydric or higher polyhydric alcohols, etc.)). Examples of the polymerizable unsaturated bond include carbon-carbon double bonds and carbon-carbon triple bonds. These can be used alone or in combination of two or more. Among these, compounds having two or more polymerizable unsaturated bonds in the molecule are preferred.

　Examples of the monomer having two or more polymerizable unsaturated bonds in the molecule as the polymerizable compound include bisphenol A di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, glycerol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, etc.

The content of the polymerizable compound in the coloring composition is preferably 10 parts by mass to 1,000 parts by mass, and more preferably 20 parts by mass to 500 parts by mass, per 100 parts by mass of the coloring material. If the content of the polymerizable compound is within the above range, sufficient curability is obtained and alkaline developability is also good. It is also preferable to use an alkali-soluble resin and a polymerizable compound in combination as the binder resin.

(Thermosetting resin, thermoplastic resin)
Examples of the thermosetting resin and thermoplastic resin include butyral resin, styrene-maleic acid copolymer, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyurethane resin, phenol resin, polyester resin, (meth)acrylic resin, alkyd resin, styrene resin, polyamide resin, rubber resin, cyclized rubber, epoxy resin, cellulose, polybutadiene, polyimide resin, benzoguanamine resin, melamine resin, and urea resin.

(Photopolymerization initiator)
The coloring composition of the present invention may contain a photopolymerization initiator as necessary. This can impart radiation sensitivity to the coloring composition. The photopolymerization initiator is a compound that generates an active species that can initiate polymerization of a polymerizable compound by exposure to radiation such as visible light, ultraviolet light, far infrared light, electron beams, and X-rays.

The photopolymerization initiator may, for example, be a thioxanthone-based compound, an acetophenone-based compound, a biimidazole-based compound, a triazine-based compound, an O-acyloxime-based compound, an onium salt-based compound, a benzoin-based compound, a benzophenone-based compound, an α-diketone-based compound, a polynuclear quinone-based compound, a diazo-based compound, an imide sulfonate-based compound, or the like. The photopolymerization initiator may be used alone or in a mixture of two or more types.

In the coloring composition of the present invention, the content of the photopolymerization initiator is preferably 0.01 parts by mass to 120 parts by mass, and more preferably 1 part by mass to 100 parts by mass, relative to 100 parts by mass of the polymerizable compound. In this case, if the content of the photopolymerization initiator is too low, there is a risk that curing due to exposure to light will be insufficient, while if the content is too high, the formed coloring layer will tend to easily fall off from the substrate during development.

(Other compounding agents)
In the coloring composition of the present invention, other compounding agents can be added in addition to the above compounding agents, so long as the preferable physical properties of the present invention are not impaired. Examples of other compounding agents include dispersants other than the block copolymers (urethane-based dispersing agents, polyethyleneimine-based dispersing agents, polyoxyethylene alkyl ether-based dispersing agents, polyoxyethylene glycol diester-based dispersing agents, sorbitan aliphatic ester-based dispersing agents, aliphatic modified polyester-based dispersing agents, etc.), sensitizing dyes, thermal polymerization inhibitors, surfactants (nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants), plasticizers, organic carboxylic acid compounds, organic carboxylic anhydrides, antioxidants, ultraviolet absorbers, light stabilizers, pH adjusters, preservatives, antifungal agents, aggregation inhibitors, adhesion improvers, development improvers, storage stabilizers, etc.

Sensitizing dyes include 4,4'-dimethylaminobenzophenone, 4,4'-diethylaminobenzophenone, 2-aminobenzophenone, 4-aminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, 3,4-diaminobenzophenone, 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-diethylaminophenyl)1,3,4- Examples include oxazole, 2-(p-dimethylaminophenyl)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, etc.

Thermal polymerization inhibitors include hydroquinone, p-methoxyphenol, pyrogallol, catechol, 2,6-t-butyl-p-cresol, and β-naphthol.

Nonionic surfactants include fluorine-based surfactants (1,1,2,2-tetrafluorooctyl (1,1,2,2-tetrafluoropropyl) ether, 1,1,2,2-tetrafluorooctylhexyl ether, octaethylene glycol di(1,1,2,2-tetrafluorobutyl) ether, hexaethylene glycol di(1,1,2,2,3,3-hexafluoropentyl) ether, octapropylene glycol di(1,1,2,2-tetrafluorobutyl) ether, hexapropylene glycol di(1,1,2,2,3,3-hexafluoropentyl) ether, sodium perfluorododecyl sulfonate, 1,1,2,2,8,8,9,9,10,10-decafluorododecane, 1,1,2,2, 3,3-hexafluorodecane, etc.), silicone surfactants, polyoxyethylene surfactants (polyoxyethylene alkyl ethers, polyoxyethylene polyoxypropylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl esters, polyoxyethylene fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, pentaerythritol fatty acid esters, polyoxyethylene pentaerythritol fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, sorbitol fatty acid esters, polyoxyethylene sorbitol fatty acid esters, etc.), etc.

Anionic surfactants include alkyl sulfonates, alkyl benzene sulfonates, alkyl naphthalene sulfonates, polyoxyethylene alkyl ether sulfonates, alkyl sulfates, alkyl sulfate ester salts, higher alcohol sulfate ester salts, aliphatic alcohol sulfate ester salts, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, alkyl phosphate ester salts, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl phenyl ether phosphates, special polymer surfactants, etc.

Cationic surfactants include quaternary ammonium salts, imidazoline derivatives, alkylamine salts, etc.

Examples of amphoteric surfactants include betaine-type compounds, imidazolium salts, imidazolines, amino acids, etc.

Plasticizers include dioctyl phthalate, didodecyl phthalate, triethylene glycol dicaprylate, dimethyl glycol phthalate, tricresyl phosphate, dioctyl adipate, dibutyl sebacate, and triacetyl glycerin.

Organic carboxylic acid compounds include aliphatic monocarboxylic acids such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, pivalic acid, caproic acid, glycolic acid, acrylic acid, and methacrylic acid; aliphatic dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, cyclohexanedicarboxylic acid, cyclohexenedicarboxylic acid, itaconic acid, citraconic acid, maleic acid, and fumaric acid; aliphatic tricarboxylic acids such as tricarballylic acid and aconitic acid; aromatic carboxylic acids in which a carboxyl group is directly bonded to a phenyl group such as benzoic acid, phthalic acid, trimesic acid, pyropetoic acid, and mellophanic acid; and aromatic carboxylic acids in which a carboxyl group is bonded to a phenyl group via a carbon bond such as phenylacetic acid, hydroatropic acid, hydrocinnamic acid, phenylsuccinic acid, and cinnamylindeneacetic acid. By including an organic carboxylic acid compound, alkaline developability and background scumming can be improved.

Examples of organic carboxylic acid anhydrides include acetic anhydride, trichloroacetic anhydride, trifluoroacetic anhydride, tetrahydrophthalic anhydride, succinic anhydride, maleic anhydride, citraconic anhydride, itaconic anhydride, glutaric anhydride, 1,2-cyclohexene dicarboxylic anhydride, n-octadecylsuccinic anhydride, 5-norbornene-2,3-dicarboxylic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, and naphthalic anhydride. The inclusion of an organic carboxylic acid anhydride can improve alkaline developability and background scumming.

<Method of producing colored composition>
The coloring composition can be prepared by mixing a coloring material, a dispersant (or a dispersant solution), a dispersion medium, and, if necessary, a binder resin, a photopolymerization initiator, and other compounding agents. For mixing, for example, a mixer/disperser such as a paint shaker, a bead mill, a ball mill, a dissolver, or a kneader can be used. The coloring composition is preferably filtered after mixing. When the coloring composition has alkaline developability, it can be suitably used for color filters. As the alkaline developer, an aqueous solution containing an organic solvent or a surfactant and an alkaline compound such as potassium hydroxide, sodium hydrogen carbonate, sodium carbonate, or tetramethylammonium hydroxide can be used.

<Color filter>
The color filter of the present invention comprises a colored layer formed using the colored composition.

The following method can be used to manufacture a color filter. First, a coloring composition in which, for example, a red pigment is dispersed is applied to a transparent substrate such as a thermoplastic resin sheet such as polyester resin, polyolefin resin, polycarbonate resin, or polymethyl methacrylate resin, a thermosetting resin sheet such as epoxy resin, unsaturated polyester resin, or poly(meth)acrylic resin, or various types of glass. Then, the coating is exposed to light through a photomask, and developed using an alkaline developer (an aqueous solution containing an organic solvent or a surfactant and an alkaline compound such as potassium hydroxide, sodium bicarbonate, sodium carbonate, or tetramethylammonium hydroxide) to dissolve and remove the unexposed portion of the coating. Then, post-baking is performed to form a pixel array in which red pixel patterns are arranged in a predetermined arrangement. Next, a green coloring composition or a blue coloring composition is used, and the coating, pre-baking, exposure, development, and post-baking of each coloring composition are performed in the same manner as above to sequentially form a green pixel array and a blue pixel array on the same substrate. This results in a color filter in which a pixel array of the three primary colors of red, green, and blue is arranged on the substrate. However, in the present invention, the order in which the pixels of each color are formed is not limited to the above. In addition, a black matrix may be provided on the transparent substrate used to form the pixel array of the three primary colors of red, green, and blue.

When applying the coloring composition to a substrate, any suitable application method can be used, such as spraying, roll coating, rotary coating (spin coating), slit die coating, bar coating, etc., but it is particularly preferable to use spin coating and slit die coating.

　If necessary, a protective film is formed on the pixel pattern thus obtained, and then a transparent conductive film (ITO, etc.) 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 brightness, dimensional accuracy, etc., and can be suitably used in color liquid crystal display elements, color image pickup tube elements, color sensors, organic EL display elements, electronic paper, etc.

The present invention will be described in more detail below based on specific examples. The present invention is not limited to the following examples, and can be modified as appropriate within the scope of the present invention. The polymerization rate, weight average molecular weight (Mw), molecular weight distribution (Mw/Mn), amine value, and acid value of the block copolymer, as well as the viscosity of the colored composition, were evaluated according to the following methods.

The meanings of the abbreviations are as follows:
BTEE: Ethyl 2-methyl-2-n-butyltellanyl-propionate DBDT: Dibutyl ditelluride AIBN: 2,2'-azobis(isobutyronitrile)
CL5MA: 2-hydroxyethyl methacrylate with 5 mol caprolactone adduct CL5A: 2-hydroxyethyl acrylate with 5 mol caprolactone adduct H2EGM: Polyethylene glycol with terminal hydroxyl group (degree of polymerization = 2) monomethacrylate M4EGM: Polyethylene glycol (degree of polymerization = 4) methyl ether methacrylate M9EGM: Polyethylene glycol (degree of polymerization = 9) methyl ether methacrylate HEMA: 2-hydroxyethyl methacrylate HEA: 2-hydroxyethyl acrylate BMA: n-butyl methacrylate BA: n-butyl acrylate CHMA: Cyclohexyl methacrylate BzMA: Benzyl methacrylate DMAEMA: Dimethylaminoethyl methacrylate DMAEA: Dimethylaminoethyl acrylate DMAEMA.BzCl: Methacryloyloxyethyl benzyl dimethyl ammonium chloride MAA: Methacrylic acid BzCl: Benzyl chloride PMA: Propylene glycol monomethyl ether acetate

(Polymerization rate)
^1H -NMR was measured (solvent: _CDCl3 , internal standard: tetramethylsilane) using a nuclear magnetic resonance (NMR) measurement device (manufactured by Bruker Biospin, model: AVANCE500 (frequency 500 MHz)). From the obtained NMR spectrum, the integral ratio of the peak derived from the monomer to the peak derived from the polymer was obtained, and the polymerization rate of the monomer was calculated.

(Weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn))
The molecular weight was determined by gel permeation chromatography (GPC) using a high performance liquid chromatograph (Tosoh, model HLC-8320). A column of SHODEX KF-603 (φ6 mm×150 mm) (SHODEX) was used, a lithium bromide (10 mmol/L)-acetic acid (10 mmol/L)-methylpyrrolidone solution was used as the mobile phase, and a differential refractometer was used as the detector. The measurement conditions were a column temperature of 40° C., a sample concentration of 10 mg/mL, a sample injection amount of 10 μL, and a flow rate of 0.2 mL/min. A calibration curve was prepared using polystyrene (molecular weights 70,500, 37,900, 19,920, 10,200, 4,290, 2,630, and 1,150) as a standard substance, and the weight average molecular weight (Mw) and number average molecular weight (Mn) were measured. The molecular weight distribution (Mw/Mn) was calculated from the measured values.

(Amine value)
The amine value represents the mass of potassium hydroxide (KOH) equivalent to the basic component per 1 g of solid content. The measurement sample was dissolved in tetrahydrofuran, and the obtained solution was neutralized and titrated with a hydrochloric acid (0.1 mol/L)-propanol solution using a potentiometric titrator (product name: GT-06, manufactured by Mitsubishi Chemical). The amine value (B) was calculated by the following formula, with the inflection point of the titration pH curve being the titration end point.
B = 56.11 x Vs x 0.1 x f/w
B: Amine value (mg KOH/g)
Vs: Amount (mL) of hydrochloric acid (0.1 mol/L)-propanol solution required for titration
f: Potency of hydrochloric acid (0.1 mol/L)-propanol solution w: Mass (g) of the measurement sample (solid content equivalent)

(Acid value)
The acid value represents the mass of potassium hydroxide (KOH) required to neutralize the acidic components per 1 g of solid content. The measurement sample was dissolved in tetrahydrofuran, and several drops of 1.0 w/v % phenolphthalein ethanol (90) solution were added to the obtained solution as an indicator, and neutralization titration was performed with potassium hydroxide (0.1 mol/L)-ethanol solution. The point where a slight reddish color remained was set as the titration end point, and the acid value was calculated by the following formula.
A = 56.11 x Vs x 0.1 x f/w
A: Acid value (mg KOH / g)
Vs: Amount (mL) of potassium hydroxide (0.1 mol/L)-ethanol solution required for titration
f: Potassium hydroxide (0.1 mol/L)-ethanol solution w: Measurement sample mass (g) (solid content equivalent)

(Initial viscosity, viscosity over time)
The viscosity (mPa·s) was measured using an E-type viscometer (product name: RE-80L, manufactured by Toki Sangyo Co., Ltd.) with a cone rotor (0.8°×R24) at 25° C. and a rotor rotation speed of 60 rpm.
After preparation, the colored composition was stored at 40° C. for one day, and then the initial viscosity was measured. In addition, after preparation, the colored composition was stored at 40° C. for one week, and then the viscosity over time was measured.

(KOH (potassium hydroxide) solubility)
A coating film of the coloring composition was formed on a glass plate (50 mm x 50 mm) whose surface had been washed, using a spin coater (product name: MS-A100, manufactured by Mikasa) at 10,000 rpm for 10 seconds, and dried for 5 minutes at 100° C. Next, the glass plate on which the coating film was formed was immersed in a 0.1% aqueous potassium hydroxide solution, and the solubility was observed at 23° C. The solubility was evaluated according to the following criteria.
◯: After 1 hour, the pigment dispersion liquid was almost completely peeled off from the glass substrate.
x: Almost all of the pigment dispersion remained on the glass substrate after 1 hour.

<Synthesis of block copolymer>
(Block Copolymer No. 1)
A flask equipped with an argon gas inlet tube and a stirrer was charged with 47.56 g of BMA, 129.40 g of CL5MA, 0.849 g of AIBN, and 75.85 g of PMA, and after replacing with nitrogen, 7.78 g of BTEE and 4.50 g of DBDT were added and reacted at 60° C. for 22.5 hours to polymerize the A block. The polymerization rate was 99.0%.

A mixed solution of 59.95 g of DMAEMA, 13.28 g of HEMA, 0.424 g of AIBN, and 31.40 g of PMA, which had been previously purged with argon, was added to the reaction solution, and the mixture was reacted at 60°C for 23.0 hours to polymerize the B block. The polymerization rate was 99.5%.

After the reaction was completed, the reaction solution was poured into stirred n-heptane. The precipitated polymer was filtered by suction and dried to obtain block copolymer No. 1. The resulting block copolymer No. 1 had an Mw of 19,235, an Mw/Mn of 1.64, and an amine value of 85 mg KOH/g.

(Block Copolymers No. 2 to 16)
Block copolymers No. 2 to 12 were prepared in the same manner as in the preparation of block copolymer No. 1. Tables 2 and 3 show the monomers, organic tellurium compound (BTEE), organic ditelluride compound (DBDT), azo polymerization initiator (AIBN), solvent (PMA), reaction temperature, reaction time, and polymerization rate used. Tables 4 and 5 show the composition, Mw, Mw/Mn, amine value, and acid value of each block copolymer. The content of each structural unit in the copolymer was calculated from the charge ratio and polymerization rate of the monomers used in the polymerization reaction.

(Block Copolymer No. 17)
392 mg of BzCl was added to 7.81 g of a PMA solution containing 5.0 g of solid content of block copolymer No. 1, and the mixture was reacted at 60° C. for 6 hours to quaternize the block copolymer, and then diluted with PMA to obtain a solution of block copolymer No. 17. The obtained block copolymer No. 17 had Mw of 13,089, Mw/Mn of 1.22, and an amine value of 46 mgKOH/g.

<Synthesis of alkali-soluble resin (binder resin)>
A flask equipped with an argon gas inlet tube and a stirrer was charged with 20.0 g of MAA, 80.0 g of BzMA, and 290.0 g of PMA, and after replacing with argon, 1.5 g of AIBN, 2.0 g of n-dodecanethiol, and 10.0 g of PMA were added and heated to 90° C. While maintaining the solution at 90° C., 40.0 g of MAA, 160.0 g of BzMA, 3.0 g of AIBN, 4.0 g of n-dodecanethiol, and 25.0 g of PMA were added dropwise to the solution over 1.5 hours. 60 minutes after the dropwise addition was completed, the temperature was raised to 110° C., 0.3 g of AIBN and 5.0 g of PMA were added and reacted for 1 hour, 0.3 g of AIBN and 5.0 g of PMA were further added and reacted for 1 hour, and 0.3 g of AIBN and 5.0 g of PMA were further added and reacted for 1 hour.

The resulting reaction solution was cooled to room temperature, and 120.0 g of PMA was added to obtain an alkali-soluble resin solution with a non-volatile content of 39.9%. The Mw of the alkali-soluble resin was 11,873, the Mw/Mn was 1.77, and the acid value was 127 mg KOH/g.

<Preparation of Coloring Composition>
(Coloring composition No. 1)
In order to obtain a pigment concentration of 10% by mass, 1.8 g of pigment (C.I. Pigment Red 254), a solution of block copolymer No. 1 as a dispersant (40 parts by mass of block copolymer per 100 parts by mass of pigment), a solution of alkali-soluble resin (40 parts by mass of alkali-soluble resin per 100 parts by mass of pigment), and PMA were added to a bead mill (trade name: DISPERMAT CA, manufactured by VMA-GETZMANN GmbH), and 50 g of zirconia beads (φ0.3 mm) were added and stirred for 2 hours. After stirring, the beads were filtered to prepare colored composition No. 1. The dispersion performance of the obtained colored composition was evaluated, and the results are shown in Table 4. In addition, the evaluation result of the KOH solubility of the coating film formed using colored composition No. 1 was "good".

(Coloring Compositions Nos. 2 to 17)
Colored compositions No. 2 to 17 were prepared in the same manner as in the preparation of colored composition No. 1, except that the dispersant (block copolymer) was changed. The obtained colored compositions were evaluated, and the results are shown in Tables 4 and 5. In addition, the evaluation result of the KOH solubility of the coating film formed using colored composition No. 15 was "X".

In block copolymers No. 1 to 11 and 17, the A segment does not substantially contain a structural unit (b-2) having a basic group, the B segment contains a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group, and the molar ratio ((b-1)/(b-2)) of the structural unit (b-1) to the structural unit (b-2) in the B segment is 5/95 to 95/5.
Colored compositions Nos. 1 to 12, which used these block copolymers Nos. 1 to 11 and 17 as dispersants, all had low initial viscosities and small differences in viscosity over time, and had high dispersibility of the colorant.

Block copolymers No. 12 to 14 have a molar ratio ((b-1)/(b-2)) of the structural unit (b-1) to the structural unit (b-2) in the B segment of less than 5/95. Colored compositions No. 13 to 15 using these block copolymers No. 12 to 14 had low initial viscosities, but high aging viscosities and poor storage stability.

Block copolymers No. 15 and 16 are cases where the B segment does not contain the structural unit (b-2) having a basic group. Coloring compositions No. 16 and 17 using these block copolymers No. 15 and 16 had high initial viscosity and poor dispersibility of the coloring material.

The present invention includes the following aspects:

(Aspect 1)
A block copolymer having an A segment and a B segment,
the A segment does not substantially contain a structural unit (b-2) having a basic group,
the B segment contains a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group,
A block copolymer, characterized in that the molar ratio ((b-1)/(b-2)) of the structural unit (b-1) to the structural unit (b-2) in the B segment is 5/95 to 95/5.

(Aspect 2)
The block copolymer according to aspect 1, wherein the difference (δ _h1 - δ _h2 ) between the hydrogen bonding strength term (δ h1 ) of the Hansen solubility parameter of the structural unit (b-1) and the hydrogen bonding strength term (δ _h2 ) of the Hansen solubility parameter of the structural unit ( _b -2) is 0.5 ^{J 1/2} cm ^1/2 mol ^-1 or more.

(Aspect 3)
3. The block copolymer according to claim 1 or 2, wherein the amine value of the block copolymer is from 10 mg KOH/g to 150 mg KOH/g.

(Aspect 4)
The block copolymer according to any one of aspects 1 to 3, wherein the structural unit (b-1) is a structural unit represented by formula (1):

(Aspect 5)
The block copolymer according to any one of aspects 1 to 4, wherein the structural unit (b-2) is a structural unit represented by formula (2):

(Aspect 6)
The block copolymer according to any one of aspects 1 to 5, wherein 80 mol % or more of structural units derived from a (meth)acrylic monomer are contained in 100 mol % of structural units constituting the A segment.

(Aspect 7)
The block copolymer according to any one of Aspects 1 to 6, wherein the A segment contains a structural unit derived from one or more (meth)acrylic monomers selected from the group consisting of a (meth)acrylic monomer having a chain alkyl group, a (meth)acrylic monomer having a cyclic alkyl group, a (meth)acrylic monomer having an aryl group, a (meth)acrylic monomer having a hydroxy group, a (meth)acrylic monomer having an alkoxy group, a (meth)acrylic monomer having an oxygen-containing heterocyclic group, a (meth)acrylic monomer having an amide group, and a (meth)acrylic monomer having an acidic group.

(Aspect 8)
A block copolymer according to any one of claims 1 to 7, wherein the content of the structural unit (b-1) in 100 mol % of the structural units constituting the B segment is 5 mol % to 90 mol %.

(Aspect 9)
A molar ratio of the total molar amount of the structural units constituting the A segment to the total molar amount of the structural units constituting the B segment (A segment/B segment) is 30/70 to 75/25. The block copolymer according to any one of claims 1 to 8.

(Aspect 10)
The block copolymer according to any one of claims 1 to 9, wherein the weight average molecular weight of the block copolymer is 5,000 to 40,000.

(Aspect 11)
The block copolymer according to any one of claims 1 to 10, wherein the block copolymer is obtained by living polymerization and has a molecular weight distribution (Mw/Mn) of less than 3.0.

(Aspect 12)
A dispersant comprising the block copolymer according to any one of Aspects 1 to 11.

(Aspect 13)
A coloring composition comprising a colorant, a dispersion medium, and the dispersant according to aspect 12.

(Aspect 14)
The coloring composition according to embodiment 13, which is for use in a color filter.

(Aspect 15)
A color filter comprising a colored layer formed using the colored composition according to Aspect 14.

Claims

A block copolymer having an A segment and a B segment,
the A segment does not substantially contain a structural unit (b-2) having a basic group,
the B segment contains a structural unit (b-1) having a hydroxy group and a structural unit (b-2) having a basic group,
A block copolymer, characterized in that the molar ratio ((b-1)/(b-2)) of the structural unit (b-1) to the structural unit (b-2) in the B segment is 5/95 to 95/5.
The block copolymer according to claim 1, wherein the difference (δ h1 - δ h2 ) between the hydrogen bond strength term (δ h1 ) of the Hansen solubility parameter of the structural unit (b-1) and the hydrogen bond strength term (δ h2 ) of the Hansen solubility parameter of the structural unit ( b -2) is 0.5 J 1/2 cm 1/2 mol -1 or more.
The block copolymer according to claim 1 or 2, wherein the amine value of the block copolymer is 10 mg KOH/g to 150 mg KOH/g.
The block copolymer according to claim 1 or 2, wherein the structural unit (b-1) is a structural unit represented by formula (1):

[In formula (1), R 11 represents a hydrogen atom or a methyl group. A 11 represents an ester group, an amide group, or a single bond. R 12 represents a divalent hydrocarbon group, -R 13 -(OCO-R 14 ) m - group, or -R 15 -(O-R 16 ) n - group. R 13 to R 16 each independently represent a divalent hydrocarbon group. m represents an integer from 1 to 10. n represents an integer from 1 to 10.]
The block copolymer according to claim 1 or 2, wherein the structural unit (b-2) is a structural unit represented by formula (2):

[In formula (2), R21 represents a hydrogen atom or a methyl group. A21 represents an ester group, an amide group, or a single bond. R22 represents a divalent hydrocarbon group. R23 and R24 each independently represent a hydrocarbon group that may contain a heteroatom. R23 and R24 may be bonded to each other to form a cyclic structure.]
The block copolymer according to claim 1 or 2, in which the content of structural units derived from (meth)acrylic monomers in 100 mol % of the structural units constituting the A segment is 80 mol % or more.
The block copolymer according to claim 1 or 2, wherein the A segment contains structural units derived from one or more (meth)acrylic monomers selected from the group consisting of (meth)acrylic monomers having a chain alkyl group, (meth)acrylic monomers having a cyclic alkyl group, (meth)acrylic monomers having an aryl group, (meth)acrylic monomers having a hydroxy group, (meth)acrylic monomers having an alkoxy group, (meth)acrylic monomers having an oxygen-containing heterocyclic group, (meth)acrylic monomers having an amide group, and (meth)acrylic monomers having an acidic group.
The block copolymer according to claim 1 or 2, wherein the content of the structural unit (b-1) in 100 mol % of the structural units constituting the B segment is 5 mol % to 90 mol %.
The block copolymer according to claim 1 or 2, wherein the molar ratio (A segment/B segment) of the total molar amount of the structural units constituting the A segment to the total molar amount of the structural units constituting the B segment is 30/70 to 75/25.
The block copolymer according to claim 1 or 2, wherein the weight average molecular weight of the block copolymer is 5,000 to 40,000.
The block copolymer according to claim 1 or 2, wherein the block copolymer is obtained by living polymerization and has a molecular weight distribution (Mw/Mn) of less than 3.0.
A dispersant containing the block copolymer according to claim 1 or 2.
A coloring composition comprising a colorant, a dispersion medium, and the dispersant described in claim 12.
The coloring composition according to claim 13, which is for use in a color filter.
A color filter comprising a colored layer formed using the colored composition according to claim 14.