JP2022158618A - Block copolymer, dispersant, and coloring composition - Google Patents

Abstract

To provide a block copolymer that can be used as a dispersant for an aqueous coating, the block copolymer allowing improved dispersion of a coloring material.SOLUTION: A block copolymer has an A block containing a constitutional unit represented by formula (1) and a B block containing a constitutional unit represented by formula (3).SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a block copolymer, and more particularly to a block copolymer that can be used as a dispersant for coloring materials in coloring compositions.

In recent years, from the viewpoint of preventing air pollution, it is required to reduce the amount of volatile organic compounds (VOC) emitted from factories and business establishments. For this reason, the switch to water-based paints for the paints used for coating metal plates that form the bodies of automobiles and the like is under study. In addition, in automotive paints, in addition to coating film performance such as high durability, acid resistance, car wash scratch resistance, and chipping resistance, the finished appearance of the coating film, such as transparency and color development, is also improved. requested.

Colorants used in paints generally have hydrophobic surfaces. Dispersants used in solvent-type colored paints have low solubility in water and poor dispersion stability in aqueous dispersion media. In particular, carbon particles such as carbon black used as a black colorant have a small primary particle size and an extremely large specific surface area, and therefore have a very strong cohesive force. Therefore, it is difficult to disperse the carbon particles uniformly in the aqueous dispersion medium, and even if they are dispersed, they aggregate.

Therefore, in paints using carbon black as a black colorant, techniques for improving the dispersibility of carbon black have been proposed. For example, in Patent Document 1, carbon black contained in a DBP oil amount of 150 ml/100 g or less, an average primary particle diameter of 15 nm or less, a specific surface area of 500 m ² /g or less, and a pH in the acidic to neutral range is treated with a dispersant. A highly jet-black dispersion of fine particles dispersed in an aqueous medium (sometimes referred to as jet-black when the colorant is a black colorant among the color-developing properties) is described. In Patent Document 1, the dispersibility of carbon black is improved by controlling the physical properties of carbon black (see Patent Document 1 (claim 1, paragraphs 0019, 0021, 0024)).

Further, in Patent Document 2, (A) (a) a polymerizable unsaturated monomer having a specific cationic functional group, (b) a polymerizable unsaturated monomer having a polyoxyalkylene chain, and (c) other polymerization (Claim 1, paragraph 0014). ).

On the other hand, with respect to jet-blackness, since carbon black has a reddish black color, a method of enhancing jet-blackness by adding a blue coloring agent (bluing agent) such as a phthalocyanine-based pigment is known.

JP 2008-285632 A JP 2014-5399 A

In water-based paints using carbon particles as a black colorant, paints with improved dispersibility of carbon particles have been proposed, but there is still room for improvement in preventing aggregation of carbon particles. In addition, there is a demand for improving the dispersibility of blue colorants (especially phthalocyanine pigments) using the same dispersant.

The present invention has been made in view of the above circumstances, and is a block copolymer that can be used as a dispersant for water-based paints, and has high dispersibility of colorants (especially carbon particles and blue colorants). The purpose is to provide coalescence. Further, as a further problem, when used as a dispersant for a colored composition containing carbon particles, the jet-blackness of the coating film can be improved, and when used as a dispersant for a colored composition containing a blue colorant, the coating film An object of the present invention is to provide a block copolymer capable of improving transparency and chroma.

The block copolymer of the present invention, which has been able to solve the above problems, has an A block containing a structural unit represented by formula (1) and a B block containing a structural unit represented by formula (3). and

［式（１）において、ｎ１は２～３０の整数を表す。Ｒ¹¹は水素原子又は炭素数が１～３のアルキル基を表す。Ｒ¹²は炭素数が１～３のアルキレン基を表す。Ｒ¹³は水素原子またはメチル基を表す。なお、複数存在するＲ¹²は、それぞれ同一でも異なっていてもよい。］

[In Formula (1), n1 represents an integer of 2 to 30. R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹² represents an alkylene group having 1 to 3 carbon atoms. ^R13 represents a hydrogen atom or a methyl group. A plurality of R ¹² may be the same or different. ]

［式（３）において、Ｒ³¹は水素原子またはメチル基を示す。Ｘは２価の連結基を示す。］

[In formula (3), R ³¹ represents a hydrogen atom or a methyl group. X represents a divalent linking group. ]

In the block copolymer of the present invention, the structural unit represented by the formula (1) contained in the A block has a high affinity with the aqueous dispersion medium, and the structural unit represented by the formula (3) contained in the B block adsorbs to the coloring agent. Therefore, the block copolymer can improve the dispersibility of the coloring agent by using it as a dispersing agent for the coloring agent in the aqueous coloring composition containing the aqueous dispersion medium and the coloring agent.

The block copolymer of the present invention can be used as a dispersant for water-based paints, and is particularly excellent in dispersing carbon particles and blue pigments. By using the block copolymer of the present invention as a dispersant for a colored composition containing carbon particles (black colorant), the jet-blackness of the coating film can be improved. Further, by using the block copolymer of the present invention as a dispersant for a colored composition containing a blue colorant, the transparency and chroma of the coating film can be improved.

Furthermore, since the block copolymer of the present invention is excellent in dispersibility of both carbon particles and blue colorant, it contains carbon particles (black colorant) and blue colorant (bluing agent). It can be suitably used for an aqueous coloring composition, and an aqueous coloring composition having excellent jet-blackness can be obtained.

<Block copolymer>
The block copolymer of the present invention is characterized by having an A block containing a structural unit represented by formula (1) and a B block containing a structural unit represented by formula (3).

A block copolymer contains the structural unit represented by Formula (1) with high affinity with an aqueous dispersion medium. Also, the B block contains a structural unit represented by formula (3) having a portion that adsorbs to the colorant. By using the block copolymer as a dispersant for an aqueous coloring composition containing a coloring agent, the dispersibility of the coloring agent can be improved.

An example of a preferred embodiment of the present invention will be described below. However, the following embodiments are merely examples. The present invention is by no means limited to the following embodiments.

In the present invention, "A block" can be rephrased as "A segment", and "B block" can be rephrased as "B segment". In the present invention, "vinyl monomer" means a monomer having a radically polymerizable carbon-carbon double bond in the molecule. A “structural unit derived from a vinyl monomer” refers to a structural unit in which a radically polymerizable carbon-carbon double bond of a vinyl monomer is polymerized to form a carbon-carbon single bond. "(Meth)acrylic" means "at least one of acrylic and methacrylic". "(Meth)acrylate" means "at least one of acrylate and methacrylate". "(Meth)acryloyl" means "at least one of acryloyl and methacryloyl".

(A block)
A block is a block containing a structural unit represented by formula (1). Structural units represented by formula (1) in the A block may be of one kind or may be of two or more kinds.

［式（１）において、ｎ１は２～３０の整数を表す。Ｒ¹¹は水素原子又は炭素数が１～３のアルキル基を表す。Ｒ¹²は炭素数が１～３のアルキレン基を表す。Ｒ¹³は水素原子またはメチル基を表す。なお、複数存在するＲ¹²は、それぞれ同一でも異なっていてもよい。］

[In Formula (1), n1 represents an integer of 2 to 30. R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹² represents an alkylene group having 1 to 3 carbon atoms. ^R13 represents a hydrogen atom or a methyl group. A plurality of R ¹² may be the same or different. ]

n1 in formula (1) is 2 or more, preferably 5 or more, and 30 or less, preferably 20 or less, more preferably 15 or less, still more preferably 10 or less.

The alkyl group having 1 to 3 carbon atoms represented by R ¹¹ may be linear or branched, preferably linear. Specific examples of the alkyl group having 1 to 3 carbon atoms represented by R ¹¹ include methyl group, ethyl group, n-propyl group and isopropyl group.

The alkylene group having 1 to 3 carbon atoms represented by R ¹² may be linear or branched, but is preferably linear. Specific examples of the alkylene group having 1 to 3 carbon atoms represented by R ¹² include methylene group, ethylene group, trimethylene group and propane-1,2-diyl group. R ¹² is preferably an ethylene group or a trimethylene group.

A (meth)acrylate having a polyalkylene glycol structure is exemplified as a monomer constituting the structural unit represented by formula (1). The polyalkylene glycol portion may be, for example, a mixture of ethylene oxide and propylene oxide. Examples of the (meth)acrylate having a polyalkylene glycol structure include polyethylene glycol (degree of polymerization = 2 to 30) methyl ether (meth) acrylate, polyethylene glycol (degree of polymerization = 2 to 30) ethyl ether (meth) acrylate, polyethylene glycol. (Degree of polymerization = 2 to 30) (Meth) acrylates having a polyethylene glycol structure such as propyl ether (meth) acrylate; Polypropylene glycol (Degree of polymerization = 2 to 30) Methyl ether (meth) acrylate, Polypropylene glycol (Degree of polymerization = 2) to 30) ethyl ether (meth)acrylate, polypropylene glycol (degree of polymerization = 2 to 30) and (meth)acrylate having a polypropylene glycol structural unit such as propyl ether (meth)acrylate.

The content of the structural unit represented by formula (1) is preferably 20% by mass or more, more preferably 35% by mass or more, still more preferably 50% by mass or more in 100% by mass of the A block, and is 95% by mass. % or less, more preferably 90 mass % or less, and even more preferably 80 mass % or less. When the content is 20% by mass or more, the affinity with the aqueous dispersion medium is improved, and when the content is 95% by weight or less, the affinity with the coating film-forming resin is improved.

The A block preferably further contains a structural unit represented by formula (2). Structural units represented by formula (2) in the A block may be of one kind or may be of two or more kinds. By having the structural unit represented by the formula (2), the A block further improves the affinity with the coating film-forming resin.

［式（２）において、Ｒ²¹は、置換基を有していてもよい鎖状もしくは環状の炭化水素基を表す。Ｒ²²は水素原子またはメチル基を表す。］

[In formula (2), R ²¹ represents a chain or cyclic hydrocarbon group which may have a substituent. ^R22 represents a hydrogen atom or a methyl group. ]

Examples of the chain hydrocarbon group represented by R ²¹ include a straight chain alkyl group and a branched chain alkyl group. The straight-chain alkyl group preferably has 1 to 20 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 1 to 5 carbon atoms. Examples of the linear alkyl group include methyl group, ethyl group, n-propyl group, n-butyl group, n-hexyl group, n-octyl group, n-nonyl group, n-decyl group and n-lauryl group. is mentioned. The branched-chain alkyl group preferably has 3 to 20 carbon atoms, more preferably 3 to 10 carbon atoms, and even more preferably 3 to 5 carbon atoms. Examples of branched chain alkyl groups include isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, 2-ethylhexyl group, neopentyl group and isooctyl group.

Examples of substituents possessed by the chain hydrocarbon group represented by R ²¹ include a halogen group, an alkoxy group, a benzoyl group (--COC ₆ H ₅ ), and a hydroxy group.

Cyclic hydrocarbon groups represented by R ²¹ include cyclic alkyl groups and aromatic groups, and cyclic alkyl groups and aromatic groups may have a chain portion. The number of carbon atoms in the cyclic alkyl group is preferably 4 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, and even more preferably 6 to 10 carbon atoms. Cyclic alkyl groups include cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl groups. The number of carbon atoms in the aromatic group is preferably 6 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, and even more preferably 6 to 8 carbon atoms. Aromatic groups include phenyl, tolyl, xylyl, and mesityl groups. Examples of the chain portion of the cyclic alkyl group having a chain portion and the chain portion of the aromatic group having a chain portion include an alkylene group having 1 to 12 carbon atoms, preferably an alkylene group having 1 to 6 carbon atoms, more preferably a carbon Examples include alkylene groups of numbers 1 to 3.

Examples of substituents possessed by the cyclic hydrocarbon group represented by R ²¹ include a halogen group, an alkoxy group, a chain alkyl group, and a hydroxy group.

Vinyl monomers forming the structural unit represented by formula (2) include (meth)acrylates having a chain alkyl group (straight-chain alkyl group or branched-chain alkyl group), (meth)acrylates having a cyclic alkyl group, Examples thereof include (meth)acrylates having a polycyclic structure and (meth)acrylates having an aromatic group. Among these, (meth)acrylates having a chain alkyl group (straight-chain alkyl group or branched-chain alkyl group) and (meth)acrylates having a cyclic alkyl group are preferred.

Examples of (meth)acrylates having a 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, decyl (meth)acrylate, n-lauryl (meth)acrylate, n-stearyl (meth)acrylate and the like.

Examples of (meth)acrylates having a branched alkyl group include isopropyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, isooctyl (meth)acrylate, 2- ethylhexyl (meth)acrylate, isononyl (meth)acrylate, isodecyl (meth)acrylate and the like.

The cyclic alkyl group includes a cyclic alkyl group having a monocyclic structure (eg, a cycloalkyl group). Specific examples of (meth)acrylates having a cyclic alkyl group with a monocyclic structure include cyclohexyl (meth)acrylate, methylcyclohexyl (meth)acrylate, cyclododecyl (meth)acrylate and the like.

Polycyclic structures include cyclic alkyl groups having a bridged ring structure (eg, adamantyl, norbornyl, and isobornyl groups). Specific examples of (meth)acrylates having a polycyclic structure include isobornyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, 2-methyl-2-adamantyl (Meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate and the like.

Examples of the aromatic group include an aryl group and the like, and may have a chain portion such as an alkylaryl group, an aralkyl group, an aryloxyalkyl group, and the like. Specific examples of (meth)acrylates having an aromatic group include benzyl (meth)acrylate, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate and the like.

When the structural unit represented by formula (2) is contained, the content thereof is preferably 5% by mass or more, more preferably 10% by mass or more, and still more preferably 20% by mass or more in 100% by mass of the A block. , preferably 80% by mass or less, more preferably 65% by mass or less, and even more preferably 50% by mass or less. When the content is 5% by mass or more, the affinity with the coating film-forming resin is further improved, and when the content is 80% by mass or less, the affinity with the aqueous dispersion medium is further improved.

A block may be only the structural unit represented by formula (1), or only the structural unit represented by formula (1) and the structural unit represented by formula (2), or other structures Units may be included. The total content of the structural unit represented by formula (1) and the structural unit represented by formula (2) in block A is preferably 70% by mass or more, more preferably 80% by mass or more, and still more preferably It is 90% by mass or more.

Specific examples of vinyl monomers that can form other structural units of the A block include (meth)acrylates having a hydroxy group, (meth)acrylates having a lactone-modified hydroxy group, (meth)acrylates having an alkoxy group, and acidic groups. (Meth) acrylate, (meth) acrylic acid, etc. having

(Meth)acrylates having a hydroxy group include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxy Hexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate and the like. Among these, (meth)acrylates having a hydroxyalkyl group having 1 to 5 carbon atoms are more preferred.

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

(Meth)acrylates having an alkoxy group include methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate.

Examples of acidic groups 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 ), a phosphinic acid group (--PO ₂ H ₂ ). Examples of (meth)acrylates having an acidic group include (meth)acrylates having a carboxy group, (meth)acrylates having a phosphoric acid group, and (meth)acrylates having a sulfonic acid group.

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

The content of the structural unit represented by (3) in the A block is preferably 3% by mass or less, more preferably 1% by mass or less, and still more preferably 0.1% by mass or less, and has the formula (3) It is particularly preferable not to contain the structural unit represented by.

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 any form of random copolymerization, block copolymerization, or the like in the A block. , it is preferably contained in the form of random copolymerization from the viewpoint of uniformity. For example, the A block may be formed of a copolymer of a structural unit consisting of the a1 block and a structural unit consisting of the a2 block.

(B block)
A B block is a block containing a structural unit represented by formula (3). The structural unit represented by Formula (3) in the B block may be of one kind or may be of two or more kinds.

［式（３）において、Ｒ³¹は水素原子またはメチル基を示す。Ｘは２価の連結基を示す。］

[In formula (3), R ³¹ represents a hydrogen atom or a methyl group. X represents a divalent linking group. ]

In formula (3), the divalent linking group X includes -CO- group (carbonyl group) and -COO-R ³² - group (ester group), preferably -CO- group. Although the bonding direction of the ester group is not particularly limited, the bonding mode is preferably a C—CO—O—R ³² -morpholino group.

R ³² is a single bond, an alkylene group having 1 to 10 carbon atoms (preferably 1 to 6, more preferably 1 to 3), more preferably a single bond. Specific examples of the alkylene group having 1 to 10 carbon atoms include methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group and heptamethylene group.

(Meth)acrylic monomers capable of forming the structural unit represented by formula (3) include, for example, 4-(meth)acryloylmorpholine, morpholin-4-yl (meth)acrylate, N-((meth ) acrylamidomethyl)morpholine, 2-(4-morpholinyl)ethyl (meth)acrylate and the like. Among these, 4-(meth)acryloylmorpholine is preferred, and 4-acryloylmorpholine is more preferred.

The content of the structural unit represented by formula (3) is preferably 20% by mass or more, more preferably 30% by mass or more, still more preferably 40% by mass or more, and particularly preferably 50% by mass in 100% by mass of the B block. % by mass or more, preferably 100% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less. If the content is 20% by mass or more, aggregation of the coloring material is suppressed, and an excellent coating film can be formed.

The B block may be only the structural unit represented by formula (3), or may contain other structural units.

Specific examples of vinyl monomers capable of forming other structural units of the B block are the same as those exemplified as specific examples of monomers capable of forming other structural units of the A block. and a vinyl monomer having a cyclic N-alkenyllactam structure.

The basic group is preferably an amino group in terms of raw material availability and ease of synthesis. In the present specification, the amino group refers to a general amino group structure (—NH ₂ ), as well as —NHR ⁴¹ , —NR ⁴¹ R ⁴² (R ⁴¹ and R ⁴² are Each independently represents a chain or cyclic hydrocarbon group.In addition, R ⁴¹ and R ⁴² may be combined to form a cyclic structure.) and a substituted amino group represented by and a nitrogen-containing hetero A cyclic group (pyridyl group, imidazole group, etc.) and the like are included.

Specific examples of vinyl monomers having a basic group include dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, dimethylaminobutyl (meth)acrylate, diethylaminoethyl (meth)acrylate and diethylaminopropyl (meth)acrylate. , diethylaminobutyl (meth)acrylate, ethylaminoethyl (meth)acrylate, ethylaminopropyl (meth)acrylate, ethylaminobutyl (meth)acrylate, propylaminoethyl (meth)acrylate, propylaminopropyl (meth)acrylate, propylamino Butyl (meth)acrylate, dimethylaminopropyl (meth)acrylamide, 1-vinylimidazole, 2-vinylpyridine, 4-vinylpyridine and the like.

When the B block has a structural unit derived from a vinyl monomer having a basic group, the content thereof is preferably 5% by mass or more, more preferably 10% by mass or more, more preferably 10% by mass or more in 100% by mass of the B block. It is 20% by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 65% by mass or less.

Vinyl monomers having a cyclic N-alkenyllactam structure include structural units represented by formula (4).

［式（４）において、Ｒ⁴¹は水素原子又は炭素数１～６のアルキル基を示す。ｍ４は０～４の整数を示す。ｎ４は１～３の整数を示す。］

[In formula (4), R ⁴¹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms. m4 represents an integer of 0-4. n4 represents an integer of 1-3. ]

Vinyl monomers having a cyclic N-alkenyllactam structure include, for example, N-vinylpyrrolidone, N-vinyl-5-methylpyrrolidone, N-vinyl-5-ethylpyrrolidone, N-vinyl-5-propylpyrrolidone, N-vinyl- vinyl monomers having a 5-membered ring lactam structure such as 5-butylpyrrolidone and 1-(2-propenyl)-2-pyrrolidone; vinyl monomers having a 6-membered ring lactam structure such as N-vinylpiperidone; 7 such as N-vinylcaprolactam Examples include vinyl monomers having a membered ring lactam structure. One or two or more vinyl monomers having a cyclic N-alkenyllactam structure can be used. Among these, vinyl monomers having a five-membered ring lactam structure are preferred, and N-vinylpyrrolidone is more preferred.

When the B block has a structural unit derived from a vinyl monomer having a cyclic N-alkenyllactam structure, the content thereof is preferably 5% by mass or more, more preferably 10% by mass or more, based on 100% by mass of the B block. It is more preferably 20% by mass or more, preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 65% by mass or less.

The content of the structural unit represented by the above (1) in the B block is preferably 10% by mass or less, more preferably 8% by mass or less, and still more preferably 6% by mass or less, and is represented by the formula (1) It is particularly preferred that it does not contain any structural units.

When two or more types of structural units are contained in the B block, the various structural units contained in the B block may be contained in any manner such as random copolymerization or block copolymerization in the B block. , it is preferably contained in the form of random copolymerization from the viewpoint of uniformity. For example, the B block may be formed of a copolymer of a structural unit consisting of the b1 block and a structural unit consisting of the b2 block.

(Block copolymer)
The structure of the block copolymer is preferably a linear block copolymer. The linear block copolymer may have any structure (arrangement), but from the viewpoint of the physical properties of the linear block copolymer or the physical properties of the composition, the A block is A and the B block is B When expressed as a group consisting of (AB) _m type, (AB) _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) A copolymer having at least one structure selected from is preferred. Among these, AB type diblock copolymers are preferred from the viewpoint of handling during processing and physical properties of the composition. By forming an AB type diblock copolymer, the structural unit represented by the formula (1) in the A block and the structural unit represented by the formula (3) in the B block are localized, and efficiency It is believed that it can act favorably with the pigment and the dispersion medium (solvent). The block copolymer may have blocks other than the A block and the B block.

The content of the A block is preferably 50% by mass or more, more preferably 55% by mass or more, still more preferably 60% by mass or more, and preferably 95% by mass or less, based on 100% by mass of the entire block copolymer. More preferably 90% by mass or less, still more preferably 80% by mass or less. The content of the B block is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 50% by mass or less, based on 100% by mass of the entire block copolymer. It is more preferably 45% by mass or less, still more preferably 40% by mass or less. By adjusting the content of the A block and the B block within the above range, the dispersing performance is further improved when used as a dispersant.

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

The content of the structural unit represented by formula (1) is preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more, and particularly preferably 100% by mass of the entire block copolymer. is 40% by mass or more, preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less.

The content of the structural unit represented by formula (3) is preferably 1% by mass or more, more preferably 3% by mass or more, and still more preferably 5% by mass or more in 100% by mass of the entire block copolymer, It is preferably 50% by mass or less, more preferably 45% by mass or less, even more preferably 40% by mass or less, and particularly preferably 30% by mass or less.

The molecular weight of the block copolymer is measured by a gel permeation chromatography (hereinafter referred to as "GPC") method. The weight average molecular weight (Mw) of the block copolymer is preferably 3,000 or more, more preferably 5,000 or more, still more preferably 7,000 or more, particularly preferably 10,000 or more, and 40,000 or less. is preferably 35,000 or less, and still more preferably 30,000 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 distribution (PDI) of the block copolymer is preferably 2.5 or less, more preferably 2.0 or less, and even more preferably 1.6 or less. In the present invention, the molecular weight distribution (PDI) is determined by (weight average molecular weight (Mw) of block copolymer)/(number average molecular weight (Mn) of block copolymer). The smaller the PDI, the narrower the width of the molecular weight distribution of the copolymer, and the more uniform the molecular weight of the copolymer. That is, the lower limit of PDI is 1.0. When the molecular weight distribution (PDI) of the block copolymer exceeds 2.5, it includes those with small molecular weights and those with large molecular weights.

When the B block does not contain a structural unit derived from a vinyl monomer having a basic group, the amine value of the block copolymer is preferably 10 mgKOH/g or less, more preferably 1 mgKOH/g or less, still more preferably 0.1 mgKOH. / g or less. The block copolymer preferably has substantially no amine value (the amine value is 0 mgKOH/g).

When the B block contains a structural unit derived from a vinyl monomer having a basic group, the amine value of the block copolymer is preferably 10 mgKOH/g or more, more preferably 20 mgKOH/g or more, and still more preferably 30 mgKOH/g. 200 mgKOH/g or less is preferable, 150 mgKOH/g or less is more preferable, and 100 mgKOH/g or less is more preferable.

(Method for producing block copolymer)
As a method for producing a block copolymer, the A block is first produced by the polymerization reaction of a vinyl monomer, and the monomer of the B block is polymerized on the A block; a method of polymerizing the monomers of ; and a method of separately producing the A block and the B block and then coupling the A block and the B block.

Although the polymerization method is not particularly limited, living radical polymerization is preferred. That is, the block copolymer is preferably polymerized by living radical polymerization. The living radical polymerization method maintains the simplicity and versatility of the conventional radical polymerization method. It is preferable in terms of precise control of , and easy production of a polymer having a uniform composition.

Living radical polymerization methods include a method using a transition metal catalyst (ATRP method); a method using a sulfur-based reversible chain transfer agent (RAFT method); There is a method such as a method (TERP method). Among these methods, it is preferable to use the TERP method from the viewpoint of the diversity of usable monomers, molecular weight control in the high molecular 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. 2004/072126 and methods described in WO 2004/096870.

Specific polymerization methods for the TERP method include the following (a) to (d).
(a) A method of polymerizing a vinyl monomer using an organic tellurium compound represented by formula (6).
(b) A method of polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by formula (6) and an azo polymerization initiator.
(c) A method of polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by formula (6) and an organic ditelluride compound represented by formula (7).
(d) A method of polymerizing a vinyl monomer using a mixture of an organic tellurium compound represented by formula (6), an azo polymerization initiator, and an organic ditelluride compound represented by formula (7).

［一般式（６）において、Ｒ⁶¹は、炭素数１～８のアルキル基、アリール基または芳香族ヘテロ環基を示す。Ｒ⁶²およびＲ⁶³は、それぞれ独立に、水素原子または炭素数１～８のアルキル基を示す。Ｒ⁶⁴は、炭素数１～８のアルキル基、アリール基、置換アリール基、芳香族ヘテロ環基、アルコキシ基、アシル基、アミド基、オキシカルボニル基、シアノ基、アリル基またはプロパルギル基を示す。
一般式（７）において、Ｒ⁶¹は、炭素数１～８のアルキル基、アリール基または芳香族ヘテロ環基を示す。］

[In general 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 amide group, an oxycarbonyl group, a cyano group, an allyl group or a propargyl group.
In general formula (7), R ⁶¹ represents an alkyl group having 1 to 8 carbon atoms, an aryl group or an aromatic heterocyclic group. ]

The organotellurium compounds represented by the general formula (6) are specifically ethyl-2-methyl-2-n-butyltheranyl-propionate, ethyl-2-n-butyltheranyl-propionate, (2-hydroxyethyl)-2 -methyl-methylteranyl-propionate, etc., including organotellurium compounds described in WO 2004/14848, WO 2004/14962, WO 2004/072126, and WO 2004/096870 . 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 used without particular limitation as long as it is an azo polymerization initiator used in normal radical polymerization. ,2′-azobis(2,4-dimethylvaleronitrile) (ADVN), 1,1′-azobis(1-cyclohexanecarbonitrile) (ACHN), 2,2′-azobis(4-methoxy-2,4- dimethylvaleronitrile) (V-70) and the like.

The polymerization step is carried out in a vessel purged with an inert gas, with a vinyl monomer and an organotellurium compound of general formula (6) for the purpose of promoting the reaction, controlling the molecular weight and molecular weight distribution, etc., according to the type of the vinyl monomer, and further adding an azo A system polymerization initiator and/or an organic ditelluride compound of general formula (7) is mixed. At this time, examples of the inert gas include nitrogen, argon, and helium. Argon and nitrogen are preferred. The amount of the vinyl monomer used in (a), (b), (c) and (d) may be appropriately adjusted according to the physical properties of the intended copolymer.

The polymerization reaction can be carried out without a solvent, but may be carried out by using an aprotic or protic solvent generally used in radical polymerization and stirring the mixture. Aprotic solvents that can be used include, for example, anisole, benzene, toluene, propylene glycol monomethyl ether acetate, ethyl acetate, tetrahydrofuran (THF), and the like. Examples of protic solvents include water, methanol, 1-methoxy-2-propanol and the like. A solvent may be used individually and may use 2 or more types together. The amount of the solvent to be used may be appropriately adjusted, and is preferably 0.01 ml to 50 ml per 1 g of the vinyl monomer. The reaction temperature and reaction time may be appropriately adjusted depending on the molecular weight or molecular weight distribution of the resulting copolymer, but the mixture is usually stirred at 0°C to 150°C for 1 minute to 100 hours. After completion of the polymerization reaction, the desired copolymer can be separated from the resulting reaction mixture by removing the used solvent, residual vinyl monomers, and the like by ordinary separation and purification means.

The growing terminal 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 an operation in air after the completion of the polymerization reaction. However, tellurium atoms may remain. Since a copolymer having a tellurium atom remaining at the end thereof is colored or has poor thermal stability, it is preferable to remove the tellurium atom. Examples of the method for removing tellurium atoms include a radical reduction method; a method of adsorption with activated carbon or the like; a method of adsorbing a metal with an ion exchange resin or the like; these methods can also be used in combination. The other end of the copolymer obtained by the polymerization reaction (the end opposite to the growing end) is -CR ⁶² R ⁶³ R ⁶⁴ derived from a tellurium compound (wherein R ⁶² , R ⁶³ and R ⁶⁴ are represented by the formula The same as R ⁶² , R ⁶³ and R ⁶⁴ in (6)).

<Dispersant>
The dispersant of the present invention contains the block copolymer. The dispersant contains the block copolymer as a main component (50% by mass or more), preferably contains 75% by mass or more of the block copolymer, and more preferably contains the block copolymer. Consist of coalescence only.

The dispersing agent has particularly high dispersibility with respect to carbon black, which is a black colorant, and can suppress aggregation. In addition, the dispersing agent exhibits excellent dispersing performance for carbon particles such as carbon nanotubes and graphene as well as carbon black. Therefore, the dispersant of the present invention can be suitably used as a dispersant for carbon particles, and can also be used in a conductive composition.

Dispersing the dispersant into a dispersant solution before preparing the coloring composition facilitates the dispersing of the coloring material. The solvent used for the dispersant solution is preferably a solvent that can dissolve the dispersant, does not react with these components, and has moderate volatility. Examples of the solvent include a dispersion medium used for the coloring composition described below. The content of the solvent in the dispersant solution is not particularly limited and can be adjusted as appropriate. The upper limit of the solvent content in the dispersant solution is usually 99% by mass. In addition, the lower limit of the content of the dispersing medium in the dispersant solution is usually 10% by mass, preferably 30% by mass, in consideration of the viscosity suitable for producing the colored composition described later.

<Coloring composition>
The coloring composition of the present invention contains a dispersant (block copolymer), a coloring agent, and an aqueous dispersion medium.

(colorant)
The coloring material is not particularly limited, and pigments and dyes conventionally used as coloring materials for paints can be used, but pigments are preferable from the viewpoint of light resistance and heat resistance. Examples of pigments include pigments of various colors such as red pigments, yellow pigments, orange pigments, blue pigments, green pigments, purple pigments, and black pigments. The structure of the pigment includes azo pigments such as monoazo pigments, diazo pigments, condensed diazo pigments, diketopyrrolopyrrole pigments, phthalocyanine pigments, isoindolinone pigments, isoindoline pigments, quinacridone pigments, and indigo pigments. organic pigments such as polycyclic pigments such as polycyclic pigments, thioindigo-based pigments, quinophthalone-based pigments, dioxazine-based pigments, anthraquinone-based pigments, perylene-based pigments, and perinone-based pigments; carbon black, graphite, titanium black, and copper, Inorganic pigments such as metal oxides such as iron, manganese, cobalt, chromium, nickel, zinc, calcium and silver, composite oxides, metal sulfides, metal sulfates and metal carbonates. The pigment contained in the coloring composition may be of only one type, or may be of multiple types.

Since the block copolymer exhibits particularly excellent dispersibility with respect to black pigments and blue pigments, the coloring agent is preferably at least one selected from the group consisting of black pigments and blue pigments.

Black pigments include carbon black such as furnace black, channel black, acetylene black, thermal black, lamp black, bone black; carbon nanotube; carbon nanofiber; fullerene; natural graphite; graphite; perylene pigment; lactam pigment; Black; metal oxides such as copper, iron, manganese, cobalt, chromium, nickel, zinc, calcium, silver; composite oxides; metal sulfides; metal sulfates; At least one carbon particle selected from the group consisting of carbon nanotubes.

Although the primary particle size of the carbon particles is not particularly limited, it is preferably 5 nm to 100 nm.
The specific surface area of the carbon particles is preferably 300 m ² /g to 1300 m ² /g, more preferably 400 m ² /g to 800 m ² /g. The specific surface area is measured according to JIS K 6217-3 (2001).

DBP (dibutyl phthalate) oil absorption of the carbon particles is preferably 50 ml/100 g to 150 ml/100 g, more preferably 80 ml/100 g to 120 ml/100 g. DBP oil absorption is measured according to JIS K 6217-4 (2017).

The carbon particles may have their surfaces subjected to oxidation treatment. A carboxyl group or a phenolic hydroxy group can be imparted to the surface of the carbon particles by performing an oxidation treatment. The oxidation treatment can be performed by treating the surface of the carbon particles with ozone, nitric acid, or the like. Carbon particles having a carboxyl group or a phenolic hydroxy group on the surface have an acidic pH.

The carbon particles preferably have a pH of 3 to 9, more preferably 5 to 9 when 1 g of the carbon particles are dispersed in 100 ml of water (25° C.).

Examples of blue pigments include organic pigments mainly composed of organic compounds such as phthalocyanine pigments, anthraquinone pigments, and dioxazine pigments, and these may be used alone or in combination of two or more. Among these, phthalocyanine pigments are preferable, and metal phthalocyanine pigments and monohalogenated metal phthalocyanine pigments (halogenated metal phthalocyanine pigments having one halogen atom in the molecule) are more preferable. Since polyhalogenated metal phthalocyanine pigments (halogenated metal phthalocyanine pigments having two or more halogen atoms in the molecule) are green pigments, the phthalocyanine pigments used as blue pigments are added to polyhalogenated metal phthalocyanine pigments. is not included.

As the phthalocyanine-based pigment, a compound represented by general formula (8) is particularly preferred. Since copper phthalocyanine pigments and monohalogenated copper phthalocyanine pigments have a transmission region in the short wavelength region, they can form a colored layer with higher brightness.

［式（８）において、Ｒ⁸は、それぞれ独立して、水素原子またはハロゲン原子を表す。ただし、Ｒ⁸中のハロゲン原子の個数は、０または１である。］

[In formula (8), each R ⁸ independently represents a hydrogen atom or a halogen atom. However, the number of halogen atoms in R ⁸ is 0 or 1. ]

All of R ⁸ are preferably hydrogen atoms because they transmit well light in the short wavelength region and the effects of the present invention can be easily obtained.

According to compounds classified as pigments in the color index (C.I.) as blue pigments, specifically, C.I. I. Pigment Blue 1, 1:2, 9, 14, 15, 15:1, 15:2, 15:3, 15:4, 15:5, 15:6, 16, 17, 17:1, 19, 22, 25, 27, 28, 29, 33, 35, 36, 56, 56:1, 60, 61, 61:1, 62, 63, 66, 67, 68, 71, 72, 73, 74, 75, 76, 78, 79, 80 and the like. As a phthalocyanine pigment, C.I. I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 17, 17:1 and 75 are preferred, and as the copper phthalocyanine pigment and the monohalogenated copper phthalocyanine pigment, C.I. I. Pigment Blue 15, 15:1, 15:2, 15:3, 15:4, 15:6, 16, 17, 17:1 are preferred. As an anthraquinone pigment, C.I. I. Pigment Blue 60 is preferred. As a dioxazine-based pigment, C.I. I. Pigment Blue 80 is preferred.

The number average particle diameter of the pigment may be appropriately selected according to its use, and is not particularly limited. From the viewpoint of high brightness, the coloring composition preferably contains a pigment having a number average particle diameter of 10 nm to 150 nm.

The pigment may contain a dye derivative as a dispersing aid. This dye derivative is obtained by introducing a functional group into the dye skeleton. As the pigment skeleton, a skeleton identical or similar to that of the coloring material constituting the coloring composition, and a skeleton identical or similar to that of the compound that is the raw material of the pigment are preferable. 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.

Although the amount of the dye derivative used is not particularly limited, it is preferably 4 parts by mass to 17 parts by mass with respect to 100 parts by mass of the pigment.

The upper limit of the content of the coloring material in the coloring composition, from the viewpoint of brightness, in the total solid content of the coloring composition is usually 80% by mass, preferably 70% by mass, and 60% by mass. is more preferable. Further, the lower limit of the content of the coloring agent in the coloring composition is usually 3% by mass, preferably 20% by mass, more preferably 30% by mass in the total solid content of the coloring composition. preferable. Here, the solid content is a component other than the dispersion medium, which will be described later.

The content of the dispersant for the coloring agent in the coloring composition is preferably 5 parts by weight to 200 parts by weight with respect to 100 parts by weight of the coloring material, preferably 10 parts by weight to 100 parts by weight, 10 parts by weight parts to 80 parts by mass is more preferable.

(Aqueous dispersion medium)
Aqueous dispersion media include water or aqueous solvents (water-miscible solvents). Specifically, alcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol, 1-methoxy-2-propanol, 1-butoxy-2-propanol; ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, diethylene glycol Polyhydric alcohols such as , polyethylene glycol, polypropylene glycol, and glycerin; ethers such as tetrahydrofuran, dioxane, ethylene glycol methyl ether, ethylene glycol ethyl ether, diethylene glycol methyl ether, diethylene glycol ethyl ether, triethylene glycol, monomethyl ether, and monoethyl ether ketones such as acetone, methyl ethyl ketone and isobutyl ketone; and amides such as dimethylformaldehyde and dimethylacetamide. Among these, alcohols and glycols are preferable. Aqueous solvents may be used alone or in combination of two or more.

The content of the aqueous dispersion medium in the coloring composition is not particularly limited and can be adjusted as appropriate. The upper limit of the content of the aqueous dispersion medium in the coloring composition is usually 99% by mass. In addition, the lower limit of the content of the aqueous dispersion medium in the coloring composition is usually 60% by mass, preferably 80% by mass, in consideration of the viscosity suitable for coating the coloring composition.

Depending on the application, the coloring composition may further contain a coating film-forming resin, a surfactant, a leveling agent, a filler, an ultraviolet absorber, an antioxidant, an antiseptic, an antifungal agent, a viscosity modifier, and a pH adjuster. , an antifoaming agent, a cross-linking agent and the like may be added. Further, when conductive carbon particles are used in the coloring composition, they can be used as electrodes. In this case, the coloring composition contains an electrode-forming resin, an electrode active material, a surfactant, a film forming aid, a leveling agent, an antiseptic, an antifungal agent, a viscosity modifier, a pH adjuster, an antifoaming agent, and a cross-linking agent. You may mix|blend additives, such as.

(Resin for coating film formation)
The coating film-forming resin is a component that becomes the body of the film when the coating film is formed using the coloring composition. The coating film-forming resin is not particularly limited, and those conventionally used in paints can be used. The coating film-forming resin includes thermosetting resins, thermoplastic resins, polymerizable compounds (polymerizable resins, monomers having one polymerizable unsaturated bond in the molecule, and two or more polymerizable unsaturated bonds in the molecule. (monomers, oligomers, etc.) having The coating film-forming resin can be used alone or in combination of two or more. When the coating film-forming resin is added to the coloring composition, the content of the coating film-forming resin is preferably 60% by mass to 95% by mass based on the total solid content of the coloring composition.

(thermosetting resin, thermoplastic resin)
Examples of thermosetting resins and thermoplastic resins include butyral resins, styrene-maleic acid copolymers, chlorinated polyethylene resins, chlorinated polypropylene resins, vinyl chloride resins, vinyl chloride-vinyl acetate copolymers, and vinyl acetate resins. , urethane resin, phenol resin, polyester resin, acrylic resin, alkyd resin, styrene resin, styrene acrylic resin, polyamide resin, rubber resin, cyclized rubber, epoxy resin, celluloses, polybutadiene, polyimide resin, benzoguanamine resin, melamine resin , urea resin, silicone resin, fluorine resin, and the like.

(Polymerizable compound)
As a polymerizable resin as a polymerizable compound, a linear polymer having a reactive substituent such as a hydroxy group, a carboxyl group, an amino group, etc. is added via an isocyanate group, an aldehyde group, an epoxy group, etc. to a (meth)acryl A compound, a resin into which a crosslinkable group such as cinnamic acid is introduced is used. Linear polymers containing acid anhydrides such as styrene-maleic anhydride copolymers and α-olefin-maleic anhydride copolymers are halved with (meth)acrylic compounds having hydroxyl groups such as hydroxyalkyl (meth)acrylates. Esterified polymers are also used.

(Surfactant)
Surfactants include nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants.
Nonionic surfactants include fluorine-based surfactants, silicone-based surfactants, polyoxyethylene-based surfactants, and the like.
Examples of anionic surfactants include alkylsulfonates, alkylbenzenesulfonates, alkylnaphthalenesulfonates, polyoxyethylene alkylethersulfonates, alkylsulfates, alkylsulfates, higher alcohol sulfates, aliphatic Alcohol sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkylphenyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkylphenyl ether phosphates, special polymer surfactants agents and the like.
Cationic surfactants include quaternary ammonium salts, imidazoline derivatives, alkylamine salts and the like.
Amphoteric surfactants include betaine type compounds, imidazolium salts, imidazolines, amino acids and the like.

(leveling agent)
Examples of leveling agents include silicone-based agents and fluorine-based agents. Examples of silicones include dimethylsilicone oil, methylphenylsilicone oil, alkyl-modified silicone, alkoxy-modified silicone, oxyalkyl-modified silicone, glycol-modified silicone, polyether-modified silicone, polyether-modified silicone, fatty acid ester-modified silicone, and the like. Examples of fluorine-based materials include fluorocarbon-based compounds and fluorosilicone. These can be used alone or in combination of two or more.

(filler)
Examples of fillers include silicon dioxide, alumina, zinc white, potassium titanate fiber, aluminum flakes, stainless steel powder, tin powder, gold powder, metal-plated glass powder, titanium mica, calcium carbonate, barium sulfate, barium carbonate, kaolin, and barita. , clays, other metal oxides, and composite metal oxides, which can be used singly or in combination of two or more to prevent a decrease in viscosity and poor gloss.

(Electrode-Forming Resin) The electrode-forming resin is used for binding particles such as an active material or a conductive carbon material, or binding conductive carbon particles and a current collector. Examples of the electrode-forming resin include acrylic resins, polyurethane resins, polyester resins, phenol resins, epoxy resins, phenoxy resins, urea resins, melamine resins, alkyd resins, formaldehyde resins, silicone resins, fluorine resins, carboxymethyl cellulose, and the like. Examples thereof include cellulose resins, synthetic rubbers such as styrene-butadiene rubber and fluororubber, conductive resins such as polyaniline and polyacetylene, and polymer compounds containing fluorine atoms such as polyvinylidene fluoride, polyvinyl fluoride, and tetrafluoroethylene. Modified products, mixtures, or copolymers of these resins can also be used. These resins can also be used singly or in combination.

<Method for producing colored composition>
The coloring composition can be prepared by mixing a coloring agent, a dispersant (block copolymer), an aqueous dispersion medium, and, if necessary, a coating film-forming resin and other ingredients. For mixing, for example, a mixing and dispersing machine such as a paint shaker, bead mill, ball mill, dissolver or kneader can be used. The coloring composition is preferably filtered after mixing. Coloring compositions include automotive coating compositions.

Application (coating) of the coloring composition to an object to be treated such as a stainless steel plate or an aluminum plate includes, for example, roll coating, spin coating, flow coating, slot die coating, spray coating, dip coating, electrodeposition coating, and electrostatic coating. , brush coating, powder coating, or the like. Then, if necessary, it is heated to evaporate the solvent, and the coating film is dried and cured. At this time, it may be heated or irradiated with ultraviolet rays or the like. The coating film obtained by applying the coloring composition may be coated with one or more layers of a top clear paint to form a top clear coating film. A top clear paint is a liquid paint that forms a colorless or colored transparent coating film, which is composed mainly of a resin component and a solvent and, if necessary, other paint additives.

Hereinafter, the present invention will be described in more detail based on specific examples. The present invention is by no means limited to the following examples, and can be modified as appropriate without changing the gist of the invention. The polymerization rate, weight average molecular weight (Mw), molecular weight distribution (PDI), amine value, and coating properties of the block copolymer were evaluated according to the following methods.

Abbreviations have the following meanings.
BTEE: ethyl-2-methyl-2-n-butylteranyl-propionate AIBN: 2,2'-azobis(isobutyronitrile)
BA: Butyl acrylate M9EGA: Polyethylene glycol (degree of polymerization = 9) methyl ether acrylate (manufactured by NOF Corporation, Blemmer (registered trademark) AME-400)
M11EGA: polyethylene glycol (degree of polymerization = 11) methyl ether acrylate (manufactured by Green, KOMERATE-A040TT)
VP: N-vinyl-2-pyrrolidone ACMO: 4-acryloylmorpholine DEAA: diethylacrylamide NIPAM: isopropylacrylamide DMAEMA: dimethylaminoethyl methacrylate 4VPy: 4-vinylpyridine PMA: propylene glycol monomethyl ether acetate MeOH: methanol

(Polymerization rate)
¹ H-NMR was measured (solvent: CDCl ₃ , internal standard: TMS) using a nuclear magnetic resonance (NMR) spectrometer (manufactured by Bruker Biospin, model: AVANCE500 (frequency: 500 MHz)). For the obtained NMR spectrum, the integration ratio of the peak derived from the monomer and the peak derived from the polymer was determined, and the polymerization rate of the monomer was calculated.

(Weight average molecular weight (Mw) and molecular weight distribution (PDI))
It was determined by gel permeation chromatography (GPC) using a high-performance liquid chromatograph (manufactured by Tosoh, model HLC-8320). The column is one SHODEX KF-603 (φ6 mm × 150 mm) (manufactured by SHODEX), the mobile phase is lithium bromide (10 mmol / L) - acetic acid (10 mmol / L) - methylpyrrolidone solution, the detector is a differential refractometer. used. The measurement conditions were a column temperature of 40° C., a sample concentration of 20 mg/mL, a sample injection amount of 10 μm, and a flow rate of 0.2 mL/min. Polystyrene (molecular weight 70,500, 37,900, 19,920, 10,200, 4,290, 2,630, 1,150) is used as a standard substance to create a calibration curve (calibration curve), and the weight average Molecular weight (Mw) and number average molecular weight (Mn) were measured. A molecular weight distribution (PDI=Mw/Mn) was calculated from this measured value.

(amine value)
The amine number represents the mass of potassium hydroxide (KOH) equivalent to the basic component per gram of solid content. A measurement sample was dissolved in tetrahydrofuran, and the resulting solution was neutralized and titrated with a hydrochloric acid (0.1 mol/L)-propanol solution using a potentiometric titrator (trade name: GT-06, manufactured by Mitsubishi Chemical Corporation). Using the inflection point of the titration pH curve as the titration end point, the amine value (B) was calculated by the following formula.
B = 56.11 x Vs x 0.1 x f/w
B: amine value (mgKOH/g)
Vs: Hydrochloric acid (0.1 mol / L) required for titration - amount of propanol solution used (mL)
f: Potency of hydrochloric acid (0.1 mol/L)-propanol solution w: Mass (g) of measurement sample (in terms of solid content)

(Black evaluation)
A black paint was applied to a stainless steel plate using a bar coater (#20) and dried at 60° C. for 10 minutes to form a coating film to prepare a test piece.
With respect to the coating film-formed surface of the obtained test piece, the L value was measured by removing specular reflection light using an L value measuring device (manufactured by Konica Minolta Japan, model CM-2600d). The black paint immediately after preparation and the black paint after being left at 35° C. for 3 weeks after preparation were evaluated.

(Blue rating)
A blue paint (primary color) was applied to a 100 μm transparent film using a 52 μm bar, pre-dried at 60° C., dried at 140° C. for 10 minutes to form a coating film, and test specimens were prepared. Haze was measured on the coating film-formed surface of the obtained test piece using a haze meter (manufactured by Nippon Denshoku Co., Ltd., model NDH-5000).
Also, a blue paint (aluminum split paint) was applied to a 100 μm transparent film using a 52 μm bar, pre-dried at 60° C. and dried at 140° C. for 10 minutes to form a coating film, and a test piece was prepared. The coating film-formed surface of the obtained test piece was measured using a spectrophotometer (manufactured by Konica Minolta Japan, model CM-2600d), and the chroma was calculated from C=(a ² +b ² ) ^1/2 . Calculated.

<Synthesis of block copolymer>
(Block copolymer No. 1)
A flask equipped with an argon gas inlet tube and a stirrer was charged with 9.0 g of BA, 18.0 g of M9EGA, 0.05 g of AIBN, and 6.7 g of PMA. The reaction was allowed to polymerize the A block. The polymerization rate was 95%.

To the reaction solution, a mixed solution of 10.2 g of ACMO, 0.05 g of AIBN and 9.2 g of MeOH, previously replaced with argon, was added and reacted at 60° C. for 36 hours to polymerize the B block. The polymerization rate was 100%.

After completion of the reaction, the reaction solution was poured into n-heptane which was being stirred. Block copolymer No. 1 was obtained by filtering the precipitated polymer with suction and drying it. got 1. Obtained block copolymer no. 1 had a Mw of 26,312 and a PDI of 1.25.

(Block copolymer Nos. 2 to 8)
Block copolymer no. Block copolymer No. 1 was prepared in the same manner as in the production method of No. 1. 2 to 8 were produced. Table 1 shows the monomers, organotellurium compounds, azo polymerization initiators, solvents, reaction conditions, and polymerization rates used. Table 2 shows the composition, Mw, PDI, and amine value of each block copolymer. The content of each structural unit in the copolymer was calculated from the charging ratio and polymerization rate of the monomers used in the polymerization reaction.

(Black paint No. 1-8)
As a dispersant, block copolymer No. 1 obtained above was used. 1-8 were used to prepare black paints. Specifically, each component was put into a 50 mL mayonnaise bottle so as to have the formulation shown in Table 3, 66 g of zirconia beads (φ0.3 mm) were added, and a disperser (SKANDEX DISPERSER BA-S20, manufactured by Orwell) was used. and stirred for 5 hours. After the stirring was completed, the beads were separated by filtration to obtain a pigment dispersion. By mixing the obtained pigment dispersion and the clear paint, a black paint No. 1-8 were prepared. The obtained black paint No. For 1 to 8, it was visually confirmed that the dispersibility of carbon black was good.

黒色顔料：商品名「ＥＭＰＥＲＯＲ（登録商標）２０００」、キャボットコーポレーション社製、カーボンブラック、ｐＨ６～９
消泡剤：商品名「ＢＹＫ－０２４」、ビックケミー社製、シリコーン系界面活性剤
アクリル樹脂：商品名「ウォーターゾール（登録商標）ＡＣＤ－２００１」、ＤＩＣ社製、不揮発分；４０質量％、溶媒；水、プロピレングリコール－ｎ－ブチルエーテル
メラミン樹脂：商品名「サイメル（登録商標）３０３ＬＦ」、ａｌｌｎｅｘ社製、メチル化メラミン樹脂、不揮発分；１００質量％

Black pigment: trade name "EMPEROR (registered trademark) 2000", manufactured by Cabot Corporation, carbon black, pH 6-9
Antifoaming agent: trade name "BYK-024", manufactured by BYK-Chemie, silicone surfactant Acrylic resin: trade name "Watersol (registered trademark) ACD-2001", manufactured by DIC, nonvolatile content: 40% by mass, solvent ; water, propylene glycol-n-butyl ether melamine resin: trade name "Cymel (registered trademark) 303LF", manufactured by allnex, methylated melamine resin, non-volatile content; 100% by mass

(Blue paint No. 1-8)
As a dispersant, block copolymer No. 1 obtained above was used. A blue paint (primary color, aluminum split paint) was prepared using 1 to 8. Specifically, each component was put into a 50 mL mayonnaise bottle so as to have the formulation shown in Table 4, 66 g of zirconia beads (φ0.3 mm) were added, and a disperser (SKANDEX DISPERSER BA-S20, manufactured by Orwell) was used. and stirred for 5 hours. After the stirring was completed, the beads were separated by filtration to obtain a pigment dispersion. By mixing the obtained pigment dispersion and clear paint, or the pigment dispersion and aluminum primary color, blue paint No. 1 to 8 (primary color, aluminum split paint) were prepared. The obtained blue paint No. For 1 to 8 (primary color, aluminum split paint), it was visually confirmed that the dispersibility of the blue pigment was good.

青色顔料：商品名「ＣＹＡＮＩＮＥ Ｂｌｕｅ Ｇ－３１４Ｒ」、山陽色素社製、塩素化銅フタロシアニン顔料（Ｃ．Ｉ．Ｐｉｇｍｅｎｔ Ｂｌｕｅ１５：１）
消泡剤：商品名「ＢＹＫ－０２４」、ビックケミー社製、シリコーン系界面活性剤
アクリル樹脂：商品名「ウォーターゾール（登録商標）ＡＣＤ－２００１」、ＤＩＣ社製、不揮発分；４０質量％、溶媒；水、プロピレングリコール－ｎ－ブチルエーテル
メラミン樹脂：商品名「サイメル（登録商標）３０３ＬＦ」、ａｌｌｎｅｘ社製、メチル化メラミン樹脂、不揮発分；１００質量％
水性用アルミ：商品名「ＳＴＡＰＡ ＩＬ ＨＹＤＲＯＬＡＮ Ｓ ４１２」、ＥＣＫＡＲＴ社製、アルミニウムペースト

Blue pigment: trade name "CYANINE Blue G-314R", manufactured by Sanyo Color Co., Ltd., chlorinated copper phthalocyanine pigment (CI Pigment Blue 15: 1)
Antifoaming agent: trade name "BYK-024", manufactured by BYK-Chemie, silicone surfactant Acrylic resin: trade name "Watersol (registered trademark) ACD-2001", manufactured by DIC, nonvolatile content: 40% by mass, solvent ; water, propylene glycol-n-butyl ether melamine resin: trade name "Cymel (registered trademark) 303LF", manufactured by allnex, methylated melamine resin, non-volatile content; 100% by mass
Water-based aluminum: trade name "STAPA IL HYDROLAN S 412", manufactured by ECKART, aluminum paste

Block copolymer no. 1 to 5 have an A block containing a structural unit represented by formula (1) and a B block containing a structural unit represented by formula (3). These block copolymer nos. The black paints using Nos. 2 to 5 had low L values of the produced coating films both immediately after preparation and after storage for 3 weeks. Moreover, these block copolymer Nos. The haze value of the coating film formed from the blue paint (primary color) using 1 to 5 was low. Furthermore, the chroma of the coating film formed from the blue paint (aluminum split paint) was high. Therefore, these block copolymer Nos. 1 to 5 have high dispersibility for both black colorants and blue colorants.

Block copolymer no. 6 to 8 are cases where there is no B block containing the structural unit represented by formula (3). These block copolymer nos. Black paints using Nos. 6 to 8 had high L values for the coating films produced both immediately after preparation and after storage for 3 weeks. Also, this block copolymer No. Blue paints using 6 to 8 (primary colors) had high haze values in the coating films produced. Furthermore, block copolymer No. The chroma of the coating film formed from the blue paint (aluminum split paint) using Nos. 6 to 8 was low.

The block copolymer of the present invention can be used as a dispersant for coloring compositions containing a coloring agent and an aqueous dispersion medium, and is particularly useful as a dispersant for carbon particles. INDUSTRIAL APPLICABILITY The coloring composition of the present invention is useful for automotive coatings and the like because the resulting coating film has a high jet-blackness.

Claims (14)

A block copolymer comprising an A block containing a structural unit represented by formula (1) and a B block containing a structural unit represented by formula (3).

[In Formula (1), n1 represents an integer of 2 to 30. R ¹¹ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. R ¹² represents an alkylene group having 1 to 3 carbon atoms. ^R13 represents a hydrogen atom or a methyl group. A plurality of R ¹² may be the same or different. ]

[In formula (3), R ³¹ represents a hydrogen atom or a methyl group. X represents a divalent linking group. ] 2. The block copolymer according to claim 1, wherein the content of the structural unit represented by formula (1) is 20% by mass to 95% by mass in 100% by mass of the A block. 3. The block copolymer according to claim 1, wherein the content of the structural unit represented by formula (3) is 20% by mass to 100% by mass in 100% by mass of the B block. The block copolymer according to any one of claims 1 to 3, wherein the mass ratio (A block/B block) of the A block and the B block in the block copolymer is 50/50 to 95/5. Combined. The block copolymer according to any one of claims 1 to 4, wherein the A block further contains a structural unit represented by formula (2).

[In formula (2), R ²¹ represents a chain or cyclic hydrocarbon group which may have a substituent. ^R22 represents a hydrogen atom or a methyl group. ] The block copolymer according to any one of claims 1 to 5, wherein the block copolymer has a molecular weight distribution (PDI) of 2.5 or less. The block copolymer according to any one of claims 1 to 6, wherein the block copolymer has a weight average molecular weight (Mw) of 3,000 to 40,000. The block copolymer according to any one of claims 1 to 7, which is polymerized by living radical polymerization. A dispersant comprising the block copolymer according to any one of claims 1 to 8. A coloring composition comprising the dispersant according to claim 9, a coloring agent, and an aqueous dispersion medium. 11. The coloring composition according to claim 10, wherein the coloring agent is at least one selected from the group consisting of black pigments and blue pigments. 12. The colored composition according to claim 11, further comprising a coating film-forming resin. 13. The coloring composition according to claim 12, which is an automotive coating composition. A coating film characterized by being formed from the colored composition according to any one of claims 10 to 13.