JP2009191209A - Resin composition and dispersant - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition and a dispersant using it which is a component useful for long-term stability of homogeneous dispersion of particles. <P>SOLUTION: The resin composition contains a copolymer having the following characteristics (&alpha;)-(&gamma;): (&alpha;) the polymer includes a monomer (A) having an amino group and a monomer (B) except the monomer (A); (&beta;) the overall light transmittance in a 5% solution is 95% or more and transmittance at 500 nm is 95% or more; and (&gamma;) a molecular weight distribution is 1.0-2.0. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a resin composition containing a copolymer having an amino group and a dispersant using the same.

Until now, copolymers of various monomers have been used as resin compositions for pigment dispersants, for example, and these have characteristics of each of a plurality of types of monomers compared to polymers made from a single monomer. Furthermore, there is a possibility that a copolymer having a function that is manifested for the first time can be obtained by combination.
Among the pigments, carbon black having a strong cohesive force has a problem that it is difficult to uniformly disperse in a short time, and re-aggregation occurs even if it is uniformly dispersed once.

For the purpose of solving such a problem, 10 to 85 parts by weight of a nitrogen-free neutral (meth) acrylate monomer (A) and a nitrogen-containing (meta) group having an amino group, an ammonium group, or an amide group. ) 10-60 parts by weight of the acrylic monomer (B), 10-60 parts by weight of the carboxyl group-containing (meth) acrylate monomer (C), and a macromonomer having a (meth) acryloyl group at the terminal ( A (meth) acrylic copolymer having an average molecular weight of 2,000 to 500,000 has been proposed (see, for example, Patent Document 1).
The (meth) acrylic copolymer makes it possible to disperse fine particles such as pigments, metal fine powders, metal compound fine powders and metal colloids quickly, uniformly and stably over a long period of time.
JP 2007-8873 A

  The subject of this invention is providing the resin composition which is a component useful for the long-term stability of the uniform dispersion | distribution of particle | grains, and a dispersing agent using the same.

The present invention relates to the following inventions.
1. A resin composition containing a copolymer having the following characteristics (a) to (c).
(A) A copolymer comprising a monomer (A) having an amino group and a monomer (B) excluding the monomer (A).
(B) Total light transmittance at 5% solution of 95% or more, and transmittance at 500 nm of 95% or more.
(C) Molecular weight distribution 1.0 to 2.0.
2. The resin composition as described above, wherein the copolymer is a copolymer obtained by polymerization using an organic tellurium compound-based polymerization initiator.
3. Organic tellurium compound polymerization initiator,
(A) an organic tellurium compound represented by formula (1),
(B) a mixture of an organic tellurium compound represented by formula (1) and an azo polymerization initiator,
(C) A mixture of an organic tellurium compound represented by formula (1) and an organic ditellurium compound represented by formula (2), or (d) an organic tellurium compound represented by formula (1), an azo polymerization initiator. And the resin composition as described above, which is any one of a mixture of organic ditellurium compounds represented by formula (2).

（式中、Ｒ^１は、Ｃ_１〜Ｃ_８のアルキル基、アリール基、置換アリール基又は芳香族ヘテロ環基を示す。Ｒ^２及びＲ^３は、水素原子又はＣ_１〜Ｃ_８のアルキル基を示す。Ｒ^４は、アリール基、置換アリール基、芳香族ヘテロ環基、アシル基、アミド基、オキシカルボニル基又はシアノ基を示す。）

(In the formula, R ¹ represents a C _{1 to} C ₈ alkyl group, an aryl group, a substituted aryl group or an aromatic heterocyclic group. R ² and R ³ represent a hydrogen atom or a C _{1 to} C ₈ alkyl group. R ⁴ represents an aryl group, a substituted aryl group, an aromatic heterocyclic group, an acyl group, an amide group, an oxycarbonyl group, or a cyano group.

(R ¹ Te) ₂ (2)
(In the formula, R ¹ is the same as above.)
4). A dispersant comprising the resin composition described above.
5. An aqueous pigment dispersion containing water, a pigment, and the dispersant described above.
6). A coating agent comprising the above aqueous pigment dispersion.

  The resin composition of the present invention is a component useful for the uniform dispersibility of particles such as pigments and the long-term stability of the uniform dispersion of the particles. The pigment dispersant using the resin composition can uniformly disperse the pigment and can keep the uniformly dispersed pigment stable for a long period of time.

The resin composition of the present invention is a resin composition containing a copolymer having the following characteristics (a) to (c).
(A) A copolymer comprising a monomer (A) having an amino group and a monomer (B) excluding the monomer (A).
(B) Total light transmittance at 5% solution of 95% or more, and transmittance at 500 nm of 95% or more.
(C) Molecular weight distribution 1.0 to 2.0.

The copolymer having the characteristics (a) to (c) in the resin composition can be obtained, for example, by polymerization using an organic tellurium compound polymerization initiator. In particular,
(A) an organic tellurium compound represented by formula (1),
(B) a mixture of an organic tellurium compound represented by formula (1) and an azo polymerization initiator,
(C) A mixture of an organic tellurium compound represented by formula (1) and an organic ditellurium compound represented by formula (2), or (d) an organic tellurium compound represented by formula (1), an azo polymerization initiator. And an organic tellurium compound-based polymerization initiator selected from a mixture of organic ditellurium compounds represented by formula (2).

  The organic tellurium compound used in the present invention is represented by the formula (1).

（式中、Ｒ^１は、Ｃ_１〜Ｃ_８のアルキル基、アリール基、置換アリール基又は芳香族ヘテロ環基を示す。Ｒ^２及びＲ^３は、水素原子又はＣ_１〜Ｃ_８のアルキル基を示す。Ｒ^４は、アリール基、置換アリール基、芳香族ヘテロ環基、アシル基、アミド基、オキシカルボニル基又はシアノ基を示す。）

(In the formula, R ¹ represents a C _{1 to} C ₈ alkyl group, an aryl group, a substituted aryl group or an aromatic heterocyclic group. R ² and R ³ represent a hydrogen atom or a C _{1 to} C ₈ alkyl group. R ⁴ represents an aryl group, a substituted aryl group, an aromatic heterocyclic group, an acyl group, an amide group, an oxycarbonyl group, or a cyano group.

Specific examples of the group represented by R ¹ are as follows.
Examples of the C _{1 to} C ₈ alkyl group include methyl group, ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, sec-butyl group, tert-butyl group, cyclobutyl group, and n-pentyl. Examples thereof include linear, branched or cyclic alkyl groups having 1 to 8 carbon atoms such as a group, n-hexyl group, n-heptyl group and n-octyl group. A preferable alkyl group is a linear or branched alkyl group having 1 to 4 carbon atoms. More preferably, a methyl group, an ethyl group, or an n-butyl group is good.
Examples of the aryl group include a phenyl group and a naphthyl group. A preferred aryl group is a phenyl group. Examples of the substituent for the substituted aryl include a C _{1 to} C ₈ alkyl group, a halogen atom, a hydroxyl group, an alkoxy group, an amino group, a nitro group, a cyano group, and a carbonyl-containing group represented by —COR ^a (R ^a = C ₁ alkyl group -C _8, aryl _group, alkoxy group of C 1 -C _8, an aryloxy group), a sulfonyl group, and a trifluoromethyl group.
A preferred substituted aryl group is a trifluoromethyl-substituted phenyl group.
These substituents may be substituted one or two, and the para position or ortho position is preferable.
Examples of the aromatic heterocyclic group include a pyridyl group, a pyrrole group, a furyl group, and a thienyl group.

Each group represented by R ² and R ³ is specifically as follows.
Examples of the C _{1 to} C ₈ alkyl group include the same alkyl groups as those described above for R ¹ .

Specific examples of each group represented by R ⁴ are as follows.
Examples of the aryl group, substituted aryl group, and aromatic heterocyclic group include the same groups as those described above for R ¹ .
Examples of the acyl group include a formyl group, an acetyl group, and a benzoyl group.
Examples of the amide group include carboxylic acid amides such as acetamide, malonamide, succinamide, maleamide, benzamide, and 2-fluamide, thioamides such as thioacetamide, hexanedithioamide, thiobenzamide, and methanethiosulfonamide, selenoacetamide, hexanediselenoamide, Examples include selenoamides such as selenobenzamide and methaneselenosulfonamide, N-substituted amides such as N-methylacetamide, benzanilide, cyclohexanecarboxanilide, and 2,4′-dichloroacetanilide.
Examples of the oxycarbonyl group include a group represented by —COOR ^b (R ^b = H, C _{1 to} C ₈ alkyl group, aryl group).
Specifically, carboxyl group, methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, n-butoxycarbonyl group, sec-butoxycarbonyl group, tert-butoxycarbonyl group, n-pentoxycarbonyl group, phenoxycarbonyl group, etc. Can be mentioned.
Preferred oxycarbonyl groups are a methoxycarbonyl group and an ethoxycarbonyl group.
Each group represented by R ⁴ is preferably an aryl group, a substituted aryl group, an oxycarbonyl group or a cyano group.
A preferred aryl group is a phenyl group.
Preferred examples of the substituted aryl group include a halogen atom substituted phenyl group and a trifluoromethyl substituted phenyl group.
In addition, in the case of a halogen atom, these substituents are preferably substituted by 1 to 5 pieces.
In the case of an alkoxy group or a trifluoromethyl group, one or two substituents may be substituted. In the case of one substitution, the para position or the ortho position is preferable, and in the case of two substitutions, the meta position is preferable. .
Preferred oxycarbonyl groups are a methoxycarbonyl group and an ethoxycarbonyl group.

As the preferred organic tellurium compound represented by (1), R ¹ represents a C _{1 to} C ₄ alkyl group or phenyl group, and R ² and R ³ represent a hydrogen atom or a C _{1 to} C ₄ alkyl group. , R ⁴ is preferably an aryl group, a substituted aryl group, or an oxycarbonyl group.
Particularly preferably, R ¹ represents a C _{1 to} C ₄ alkyl group or a phenyl group, R ² and R ³ represent a hydrogen atom or a C _{1 to} C ₄ alkyl group, and R ⁴ represents a phenyl group, A substituted phenyl group, a methoxycarbonyl group, and an ethoxycarbonyl group are preferable.

The organic tellurium compound represented by the formula (1) is specifically as follows.
(Methylterranylmethyl) benzene, (methylterranylmethyl) naphthalene, ethyl-2-methyl-2-methylterranyl-propionate, ethyl-2-methyl-2-n-butylterranyl-propionate, Patent Documents 2 and 3, etc. All of the described organic tellurium compounds can be exemplified.

The method for producing the organic tellurium compound represented by the formula (1) is not particularly limited, and can be produced by known methods described in Patent Documents 2 and 3 and the like.
WO 2004/14848 WO 2004/14962

For example, the compound of formula (1) can be produced by reacting a compound of formula (3), a compound of formula (4) and metal tellurium.
Specific examples of the compound of the formula (3) are as follows.

〔式中、Ｒ^２、Ｒ^３及びＲ^４は、上記と同じ。Ｘは、ハロゲン原子を示す。〕

[Wherein R ² , R ³ and R ⁴ are the same as above. X represents a halogen atom. ]

Examples of the group represented by X include halogen atoms such as fluorine, chlorine, bromine and iodine. Preferably, chlorine and bromine are good.
M (R ¹ ) m (4)
[R ¹ is the same as above. M represents an alkali metal, alkaline earth metal or copper atom. When M is an alkali metal, m is 1, when M is an alkaline earth metal, m is 2, and when M is a copper atom, m is 1 or 2. ]

Examples of M include alkali metals such as lithium, sodium and potassium, alkaline earth metals such as magnesium and calcium, and copper. Lithium is preferable.
When M is magnesium, the compound (4) may be Mg (R ¹ ) 2 or a compound represented by R ¹ MgX (X is a halogen atom) (Grignard reagent). X is preferably chlorine or bromine.

The organic ditellurium compound used in the present invention is represented by the formula (2).
(R ¹ Te) 2 (2)
(R ¹ represents a C _{1 to} C ₈ alkyl group, aryl group, substituted aryl group or aromatic heterocyclic group.)

The group represented by R ¹ is as shown in Formula (1).
A preferable compound represented by the formula (2) is a compound in which R ¹ is a C _{1 to} C ₄ alkyl group or a phenyl group.

  Specifically, the compound represented by the formula (2) includes dimethylditelluride, diethylditelluride, di-n-propylditelluride, diisopropylditelluride, dicyclopropylditelluride, di-n- Butyl ditelluride, di-sec-butyl ditelluride, di-tert-butyl ditelluride, dicyclobutyl ditelluride, diphenyl ditelluride, bis- (p-methoxyphenyl) ditelluride, bis- (p-aminophenyl) ditelluride, bis- (p -Nitrophenyl) ditelluride, bis- (p-cyanophenyl) ditelluride, bis- (p-sulfonylphenyl) ditelluride, dinaphthylditelluride, dipyridylditelluride and the like. Preferred are dimethyl ditelluride, diethyl ditelluride, di-n-propyl ditelluride, di-n-butyl ditelluride, and diphenyl ditelluride.

  In the present invention, an azo polymerization initiator may be used for the purpose of accelerating the polymerization rate. The azo polymerization initiator can be used without particular limitation as long as it is an azo polymerization initiator used in normal radical polymerization.

  For example, 2,2′-azobis (isobutyronitrile) (AIBN), 2,2′-azobis (2-methylbutyronitrile) (AMBN), 2,2′-azobis (2,4-dimethylvaleronitrile) (ADVN), 1,1′-azobis (1-cyclohexanecarbonitrile) (ACHN), dimethyl-2,2′-azobisisobutyrate (MAIB), 4,4′-azobis (4-cyanovaleric acid) (ACVA) 1,1′-azobis (1-acetoxy-1-phenylethane), 2,2′-azobis (2-methylbutyramide), 2,2′-azobis (4-methoxy-2,4- Dimethylvaleronitrile), 2,2′-azobis (2-methylamidinopropane) dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2,2′-azobis [ 2-Methyl-N- 2-hydroxyethyl) propionamide], 2,2′-azobis (2,4,4-trimethylpentane), 2-cyano-2-propylazoformamide, 2,2′-azobis (N-butyl-2-methyl) Propionamide), 2,2′-azobis (N-cyclohexyl-2-methylpropionamide) and the like.

  These azo initiators are preferably selected as appropriate according to the reaction conditions. For example, in the case of low temperature polymerization (40 ° C. or lower), 2,2′-azobis (2,4-dimethylvaleronitrile) (ADVN), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), In the case of medium temperature polymerization (40-80 ° C.), 2,2′-azobis (isobutyronitrile) (AIBN), 2,2′-azobis (2-methylbutyronitrile) (AMBN), dimethyl-2,2 '-Azobisisobutyrate (MAIB), 1,1'-azobis (1-acetoxy-1-phenylethane), 4,4'-azobis (4-cyanovaleric acid) (ACVA), 2,2'- Azobis (2-methylbutyramide), 2,2′-azobis (2-methylamidinopropane) dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane], high temperature polymerization ( 1,1'- in case of 80 ℃ or higher) Zobis (1-cyclohexanecarbonitrile) (ACHN), 2-cyano-2-propylazoformamide, 2,2′-azobis (N-butyl-2-methylpropionamide), 2,2′-azobis (N-cyclohexyl) 2-methylpropionamide), 2,2′-azobis (2,4,4-trimethylpentane), 2,2′-azobis [2-methyl-N- (2-hydroxyethyl) propionamide] Is good.

The copolymer contains a vinyl monomer (A) having an amino group.
The vinyl monomer (A) having an amino group can be used without any particular limitation. Further, a quaternized vinyl monomer may be used. These may be used alone or in combination of two or more.

  For example, the vinyl monomer which has a primary amino group can be mentioned. Specific examples include acrylamide, methacrylamide, 4-vinylaniline, aminomethyl (meth) acrylate, aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, aminobutyl (meth) acrylate, and the like.

  Moreover, the vinyl monomer which has a secondary amino group can be mentioned. Specifically, anilinostyrene, β-phenyl-p-anilinostyrene, β-cyano-p-anilinostyrene, β-cyano-β-methyl-p-anilinostyrene, β-chloro-p-anis Linostyrene, β-carboxy-p-anilinostyrene, β-methoxycarbonyl-p-anilinostyrene, β- (2-hydroxyethoxy) carbonyl-p-anilinostyrene, β-formyl-p-anilinostyrene, Anilinostyrenes such as β-formyl-β-methyl-p-anilinostyrene, α-carboxy-β-carboxy-β-phenyl-p-anilinostyrene, 1-anilinophenyl-1,3-butadiene, 1-anilinophenyl-3-methyl-1,3-butadiene, 1-anilinophenyl-3-chloro-1,3-butadiene, 3-anilinophenyl-2-methyl Til-1,3-butadiene, 1-anilinophenyl-2-chloro-1,3-butadiene, 2-anilinophenyl-1,3-butadiene, 2-anilinophenyl-3-methyl-1,3- Anilinophenylbutadienes such as butadiene and 2-anilinophenyl-3-chloro-1,3-butadiene, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-methylolacrylamide, N- (4 And N-monosubstituted (meth) acrylamides such as -anilinophenyl) methacrylamide.

  Furthermore, examples of the vinyl monomer having a tertiary amino group include N, N-disubstituted aminoalkyl (meth) acrylate and N, N-disubstituted aminoalkyl (meth) acrylamide.

  Examples of the N, N-disubstituted aminoalkyl (meth) acrylate include N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and N, N-dimethylaminopropyl (meth). Acrylate, N, N-dimethylaminobutyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N-diethylaminobutyl (meth) acrylate, N-methyl -N-ethylaminoethyl (meth) acrylate, N, N-dipropylaminoethyl (meth) acrylate, N, N-dibutylaminoethyl (meth) acrylate, N, N-dibutylaminopropyl (meth) acrylate, N, N-dibutylaminobutyl (meth) acrylate, N, N- Examples thereof include esters of acrylic acid or methacrylic acid such as dihexylaminoethyl (meth) acrylate, N, N-dioctylaminoethyl (meth) acrylate, and acryloylmorpholine.

  Among these, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dipropylaminoethyl (meth) acrylate, N, N-dioctylaminoethyl (meth) Acrylate, N-methyl-N-ethylaminoethyl (meth) acrylate and the like are particularly preferable.

  Examples of the N, N-disubstituted aminoalkyl (meth) acrylamide include N, N-dimethylaminomethyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl ( (Meth) acrylamide, N, N-dimethylaminobutyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-diethylaminobutyl (meth) acrylamide, N -Methyl-N-ethylaminoethyl (meth) acrylamide, N, N-dipropylaminoethyl (meth) acrylamide, N, N-dibutylaminoethyl (meth) acrylamide, N, N-dibutylaminopropyl (meth) acrylamide, N, N-dibutylaminobuty Acrylamide compounds such as (meth) acrylamide, N, N-dihexylaminoethyl (meth) acrylamide, N, N-dihexylaminopropyl (meth) acrylamide, N, N-dioctylaminopropyl (meth) acrylamide, or methacrylamide compounds Can be mentioned.

Among these, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-dioctylaminopropyl (meth) acrylamide and the like are particularly preferable.
The above “(meth) acrylate” is a general term for “acrylate” and “methacrylate”.

Moreover, this copolymer contains the monomer (B) except this monomer (A).
The vinyl monomer (B) can be used without particular limitation as long as it is a radically polymerizable unsaturated monomer, but when used as a pigment dispersant, it has good stability against a dispersion medium (mainly water). It is desirable to select a proper one. These are used individually by 1 type or in mixture of 2 or more types.

For example, the following can be mentioned.
Methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, (meth) acrylic (Meth) such as s-butyl acid, t-butyl (meth) acrylate, n-hexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, n-stearyl (meth) acrylate Cycloalkyl group-containing unsaturated monomers such as acrylate esters, cyclohexyl (meth) acrylate, methyl cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, and cyclododecyl (meth) acrylate. Carboxy group-containing unsaturated monomers such as (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid and maleic anhydride. 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, (Meth) acrylic acid hydroxy C2-12 alkyl ester such as 12-hydroxylauryl (meth) acrylic acid, polyethylene glycol derivative of (meth) acrylic acid, caprolactone adduct of (meth) acrylic acid, hydroxymethyl vinyl ether, Hydroxyl-containing ether monomers such as hydroxyethyl vinyl ether and hydroxypropyl vinyl ether.
Hydroxyl-containing ketone monomers such as hydroxymethyl vinyl ketone, hydroxyethyl vinyl ketone, and hydroxypropyl vinyl ketone.

  Epoxy group-containing vinyl monomers such as (meth) glycidyl acrylate. Isocyanate group-containing vinyl monomers such as 2-methacryloyloxyethyl isocyanate, vinyl group-containing vinyl monomers such as triethylene glycol dimethacrylate, sulfonic acid group-containing vinyl monomers such as 2-acrylamido-2-methylpropanesulfonic acid, 2-hydroxyethyl Reactive functional group-containing vinyl monomers such as phosphoric acid group-containing vinyl monomers such as acryloyl phosphate.

  Styrene, α-methylstyrene, 4-methylstyrene (p-methylstyrene), 2-methylstyrene (o-methylstyrene), 3-methylstyrene (m-methylstyrene), 4-methoxystyrene (p-methoxystyrene) , Pt-butylstyrene, pn-butylstyrene, p-tert-butoxystyrene, 2-hydroxymethylstyrene, 2-chlorostyrene (o-chlorostyrene), 4-chlorostyrene (p-chlorostyrene), Styrene monomers such as 2,4-dichlorostyrene. Aromatic unsaturated monomers such as 1-vinylnaphthalene, divinylbenzene, p-styrenesulfonic acid or alkali metal salts thereof (sodium salt, potassium salt, etc.), 2-vinylthiophene, N-methyl-2-vinylpyrrole, 1- Heterocyclic-containing unsaturated monomers such as vinyl-2-pyrrolidone, 2-vinylpyridine and 4-vinylpyridine.

Vinylamides such as N-vinylformamide and N-vinylacetamide.
(Meth) acrylamide monomers such as (meth) acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and N, N-dimethyl (meth) acrylamide. Α-olefins such as 1-hexene, 1-octene and 1-decene. Dienes such as butadiene, isoprene, 4-methyl-1,4-hexadiene and 7-methyl-1,6-octadiene. Carboxylic acid vinyl esters such as vinyl acetate and vinyl benzoate.
Hydroxyethyl (meth) acrylate. (Meth) acrylonitrile. Methyl vinyl ketone. Vinyl chloride. Vinylidene chloride.

Of these, carboxyl group-containing unsaturated monomers such as (meth) acrylic acid, maleic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, and maleic anhydride are preferred. Epoxy group-containing vinyl monomers such as (meth) glycidyl acrylate. 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, (meth) hydroxy C ₂ -C ₁₂ alkyl esters of hydroxyl group-containing (meth) acrylic acid such as acrylic acid 12-hydroxy lauryl, (meth) polyethylene glycol acrylic acid - Le derivative, (meth) caprolactone adduct of acrylic acid, Hydroxyl-containing ether monomers such as hydroxymethyl vinyl ether, hydroxyethyl vinyl ether and hydroxypropyl vinyl ether, and hydroxyl-containing ketone monomers such as hydroxymethyl vinyl ketone, hydroxyethyl vinyl ketone and hydroxypropyl vinyl ketone .

  The proportion of the vinyl monomer and the compound of formula (1) used may be appropriately adjusted depending on the molecular weight or molecular weight distribution of the copolymer to be obtained. Usually, the vinyl monomer is added to 20 mol of the compound of formula (1). ˜4,000 mol, preferably 40 to 400 mol.

  The use ratio of the compound of formula (1) and the azo polymerization initiator is usually 0.01-100 mol, preferably 0.1-10 mol, particularly azo polymerization initiator, with respect to 1 mol of the compound of formula (1). Preferably it is 0.1-5 mol.

  When the compound of the formula (1) and the compound of the formula (2) are used in combination, the use amount thereof is usually 0.01 to 100 mol of the compound of the formula (2) with respect to 1 mol of the compound of the formula (1), preferably Is 0.05 to 10 mol, particularly preferably 0.1 to 5 mol.

  When the compound of the formula (1), the compound of the formula (2) and the azo polymerization initiator are used in combination, the amount used is usually 1 mol of the total of the compound of the formula (1) and the compound of the formula (2). The azo polymerization initiator may be 0.01 to 100 mol, preferably 0.1 to 10 mol, and particularly preferably 0.1 to 5 mol.

  The reaction is usually carried out without a solvent, but an organic solvent or an aqueous solvent generally used in radical polymerization may be used. Examples of the organic solvent that can be used include benzene, toluene, N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), acetone, 2-butanone (methyl ethyl ketone), dioxane, hexafluoroisopropol, chloroform, tetrachloride. Examples thereof include carbon, tetrahydrofuran (THF), ethyl acetate, trifluoromethylbenzene and the like. Examples of the aqueous solvent include water, methanol, ethanol, isopropanol, n-butanol, ethyl cellosolve, butyl cellosolve, 1-methoxy-2-propanol, diacetone alcohol and the like. The amount of the solvent used may be adjusted as appropriate. For example, 0.01 to 50 ml, preferably 0.05 to 10 ml, particularly preferably 0.1 to 1 ml of the solvent is used per 1 g of the vinyl monomer. good.

  Next, the mixture is stirred. The reaction temperature and reaction time may be appropriately adjusted depending on the molecular weight or molecular weight distribution of the copolymer to be obtained, but are usually stirred at 0 to 150 ° C. for 1 minute to 100 hours. Preferably, stirring is performed at 20 to 100 ° C. for 0.1 to 30 hours. More preferably, stirring is performed at 20 to 80 ° C. for 0.1 to 15 hours. It is a feature of the present invention that a high yield and a precise molecular weight distribution can be obtained even at such a low polymerization temperature and a short polymerization time. At this time, the pressure is usually a normal pressure, but may be increased or decreased.

  After completion of the reaction, the solvent or residual monomer is removed under reduced pressure by a conventional method to take out the target polymer, or the target product is isolated by reprecipitation using a target polymer insoluble solvent. The reaction treatment can be performed by any treatment method as long as there is no problem with the object.

Moreover, since the organic tellurium compound used as an initiator in the present invention is stable to water, the copolymer of the present invention can be synthesized by an aqueous polymerization method described in Patent Document 4 shown below.
That is, the emulsion polymerization method uses a surfactant and polymerizes mainly in micelles. You may use dispersing agents, such as water-soluble polymers, such as polyvinyl alcohol, as needed. These surfactants can be used alone or in combination of two or more. The amount of the surfactant used is preferably 0.3 to 50 parts by weight, more preferably 0.5 to 50 parts by weight with respect to 100 parts by weight of the total monomers. Moreover, it is preferable that the usage-amount of water is 50-2000 weight part with respect to 100 weight part of all the monomers, More preferably, it is 70-1500 weight part. Although superposition | polymerization temperature is not specifically limited, It is preferable to carry out in the range of 0-100 degreeC, More preferably, it is 40-90 degreeC. What is necessary is just to set reaction time suitably so that a polymerization reaction may be completed according to reaction temperature or the composition of the monomer composition to be used, the kind of surfactant or a polymerization initiator, etc. Preferably within 24 hours.

  In the suspension polymerization method, a dispersant is used, and polymerization is mainly performed without using micelles. If necessary, a dispersing aid such as sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, or manganese sulfate may be used in combination with these dispersing agents. The amount of the water dispersion stabilizer used is preferably from 0.01 to 30 parts by weight, more preferably from 0.05 to 10 parts by weight, particularly preferably from 0.1 to 100 parts by weight based on 100 parts by weight of the total monomers. 5 parts by weight. Moreover, it is preferable that the usage-amount of water is 50-2000 weight part with respect to 100 weight part of all the monomers, More preferably, it is 70-1500 weight part. Although superposition | polymerization temperature is not specifically limited, It is preferable to carry out in the range of 0-100 degreeC, More preferably, it is 40-90 degreeC. What is necessary is just to set reaction time suitably so that a polymerization reaction may be completed according to reaction temperature or the composition of the monomer composition to be used, the kind of water dispersion stabilizer, a polymerization initiator, etc. Preferably within 24 hours.

In the miniemulsion polymerization method, a surfactant and a co-surfactant are used, and after the monomers are forcibly dispersed using a homogenizer or an ultrasonic device, the polymerization is performed mainly without passing through micelles. The amount of the surfactant or cosurfactant used is 0.3 to 50 parts by weight, particularly preferably 0.5 to 50 parts by weight, based on the total monomers. The ultrasonic irradiation time is 0.1 to 10 minutes, particularly preferably 0.2 to 5 minutes.
JP 2006-225524 A

  The molecular weight of the copolymer can be adjusted by the reaction time, the amount of the compound of the formula (1) and the amount of the compound of the formula (2), but a living radical polymer having a weight average molecular weight of 2,000 to 40,000 is used. Obtainable.

  The molecular weight distribution (PD = Mw / Mn) of the copolymer is controlled between 1.0 and 2.0. Furthermore, it is possible to obtain a copolymer having a narrower molecular weight distribution of 1.05 to 1.90, more preferably 1.05 to 1.80.

The total light transmittance of the copolymer is 95% or more, preferably 98% to 99.9%. If it is less than 95%, it causes discoloration of the pigment in the coating film, and gives a color change to the coating film.
The transmittance at 500 nm is 95% or more, preferably 98% to 99.9%. If it is less than 95%, it causes discoloration of the pigment in the coating film, and gives a color change to the coating film.
Therefore, the copolymer has a total light transmittance of 95% or more and a transmittance at 500 nm of 95% or more. Preferably, the total light transmittance is 98% or more and the transmittance at 500 nm is 98% or more.

  The ratio of the vinyl monomer (A) having an amino group used for the copolymer in the present invention to the vinyl monomer (B) excluding (A) is preferably 1:50 to 1: 1, more preferably. The molar ratio is preferably 1:20 to 1: 3. When the ratio of the vinyl monomer (A) having an amino group is lower than 1:50, it is difficult to adsorb.

When the organic tellurium compounds represented by formula (1) and formula (2) are used as an initiator, a tellurium atom may remain at the polymer terminal in the form of -TeR ¹ (R ¹ is the same as above).
Since the polymer in which the tellurium atom remains at the terminal is colored and is a metallic element, this residual tellurium is used from the viewpoint of improving the transparency of the pigment dispersant blended with the obtained copolymer and preventing foreign matter contamination. The metal content including atoms is 1000 ppm or less, and particularly preferably 500 ppm or less, based on the entire resin.

  The tellurium atom remaining at the molecular end is adsorbed after completion of the polymerization reaction using a radical reduction method such as tributylstannane or a thiol compound, and further activated carbon, silica gel, activated alumina, activated clay, molecular sieves and polymer adsorbent. , A method of adsorbing metal with ion exchange resin, etc., or adding a peroxide such as hydrogen peroxide or benzoyl peroxide, or blowing air or oxygen into the system to oxidize the tellurium atom at the end of the polymer In liquid state such as liquid-liquid extraction method or solid-liquid extraction method that removes residual tellurium compounds by combining with water washing and appropriate solvent, and ultrafiltration that extracts and removes only those with specific molecular weight or less A purification method and these methods can also be combined.

  The copolymer can be a block polymer of a monomer (A) having an amino group and a monomer (B) excluding the monomer (A).

As a method for producing a block polymer, a segment (A) composed of a monomer having an amino group is polymerized, and then a segment (B) composed of a monomer excluding the monomer (A) is polymerized. Depending on the order of reaction, the segment (B) -segment (A) can also be obtained.
In the above, after the production of each segment, the reaction of the next block may be started as it is, or after the reaction is finished once, the reaction of the next segment may be started after purification. Isolation of the block polymer can be performed by a usual method.

In the present invention, a dispersant containing the above resin composition can be obtained. For example, pigments, metal colloids, metal fine powders, metal compound fine powders, and the like can be dispersed in the dispersant. Moreover, the coating agent containing the aqueous pigment dispersion containing water and a pigment can also be obtained.
In the present invention, when used as a resin composition for a pigment dispersant, it is preferable to use a copolymer having a weight average molecular weight of 2,000 to 40,000, more preferably 5,000 to 30,000. It is preferable to use a copolymer having a weight average molecular weight. When the weight average molecular weight is less than 2,000, the dispersant may be detached from the pigment surface. When the weight average molecular weight exceeds 40,000, the adsorption to the pigment becomes difficult.

  The dispersant of the present invention can be used for generally commercially available pigments. For example, carbon black, acid value titanium, yellow lead, cadmium yellow, cadmium red, petal, iron black, zinc white, bitumen, ultramarine blue and other inorganic pigments and azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone Pigments, perylene / perinone pigments, dioxazine pigments, anthraquinone pigments, diketopyrrolopyrrole pigments, anthrapyrimidine pigments, anthanthrone pigments, indanthrone pigments, flavanthrone pigments, thioindigo pigments, etc. Can be used for organic pigments. In particular, it exhibits an excellent dispersion effect on carbon black.

  The blend of the pigment dispersant of the present invention with respect to the pigment is preferably 0.2 to 100 parts by weight with respect to 100 parts by weight of the pigment. If the amount is less than 0.2 parts by weight, the dispersion effect is reduced, which is not preferable. Moreover, when it uses more than 100 weight part, a hydrophilic component will become excess and will have a bad influence on coating-film performance.

  A dispersion resin can be added to the pigment dispersion obtained in the present invention as necessary. Examples of the resin used in the aqueous pigment dispersion of the present invention include an acrylic copolymer system, a styrene-acrylic acid copolymer system, a styrene-maleic acid copolymer system, an alkyd system, an epoxy system, a polyester system, a polyether system, and a urethane. There are water-dispersed resins or water-soluble resins such as acrylic resins, and acrylic copolymer-based water-dispersed resins or water-soluble resins are particularly preferable.

  The pigment dispersion obtained in the present invention may contain the following components as necessary. Examples of additives include wetting agents, surface tension adjusting agents, thickeners, pH adjusters, antifungal agents, preservatives, oxygen absorbers, ultraviolet absorbers, near infrared absorbers, water-soluble quenchers, and antioxidants. Fragrances, metal deactivators, nucleating agents, antistatic agents, flame retardants, lubricants, processing aids, cross-linking agents, silane coupling agents, etc., depending on the use and intended use of the pigment dispersion. Are appropriately selected and used.

  The pigment dispersion of the present invention can be obtained by simply mixing the pigment and the dispersant of the present invention. The mixed liquid is kneader, roll mill super mill, dissolver, high speed mixer, homomixer, sand mill, media. Good pigment dispersion can be achieved by using various pulverizers such as a mill and an attritor, and a disperser.

  By appropriately blending the pigment dispersion of the present invention into an optimal resin, it can be used to coat inks used in various printing such as flexo, offset, gravure and inkjet, and metal and resin surfaces such as building materials, automotive parts, and electrical appliance parts. It can be used for paints.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, it is not limited to these at all. In Examples and Comparative Examples, various physical properties were measured using the following equipment.
¹ H-NMR: Bruker BioSpin AVANCE 500 (500 MHz)
Molecular weight and molecular weight distribution: Gel permeation chromatograph Nippon Waters GPCV-2000 (column: Tosoh TSK-GEL GMH _XL + TSK-GEL Multipore H _XL- M, polystyrene standard: Tosoh TSK Standard)
Te content in polymer: ICP / MS

Example 1 [Synthesis of poly (2- (dimethylamino) ethyl) acrylate-polyacrylate diblock polymer]
In a nitrogen-substituted glove box, 1.0 g (7.0 mmol) of 2- (dimethylamino) ethyl acrylate (DMAEA), 190.78 μl of ethyl-2-methyl-2-n-butylteranyl-propionate (BTEE) (0 .83 mmol), 2,2′-azobis (isobutyronitrile) (AIBN) 54.74 mg (0.33 mmol) and methanol 1.0 g were reacted at 60 ° C. for 24 hours.
According to NMR analysis, the polymerization rate was 97%.
Moreover, it was the weight average molecular weight 1,170 and PD = 1.06 by TOF-MS analysis.
Next, 9.0 g (124.9 mmol) of acrylic acid (AA) and 9.0 g of methanol were added to 2- (dimethylamino) ethyl acrylate (initiator, used as a macroinitiator) obtained above. The reaction was carried out at 60 ° C. for 72 hours.
As a result of NMR analysis, the polymerization rate was 85.0%.
After completion of the reaction, drying was performed to obtain 8.55 g (yield 86%) of poly (acrylic acid 2- (dimethylamino) ethyl-polyacrylic acid diblock polymer).
After the carboxylic acid in the polymer was methyl esterified with trimethylsilyldiazomethane, the weight average molecular weight was 10,900 and PD was 1.16 by GPC analysis.

Example 2 [Synthesis of poly (2- (dimethylamino) ethyl acrylate) -polyacrylate diblock polymer]
In a nitrogen-substituted glove box, 1.6 g (11.2 mmol) of 2- (dimethylamino) ethyl acrylate (DMAEA), 152.62 μl of ethyl-2-methyl-2-n-butylteranyl-propionate (BTEE) (0 .67 mmol), 2,2′-azobis (isobutyronitrile) (AIBN) 43.79 mg (0.27 mmol) and methanol 1.6 g were reacted at 60 ° C. for 24 hours.
According to NMR analysis, the polymerization rate was 98%.
Moreover, it was the weight average molecular weight 1,640 and PD = 1.05 by TOF-MS analysis.
Next, 6.4 g (88.8 mmol) of acrylic acid (AA) and 6.4 g of methanol were added to 2- (dimethylamino) ethyl acrylate (initiator, used as a macroinitiator) obtained above. The reaction was carried out at 60 ° C. for 72 hours.
According to NMR analysis, the polymerization rate was 89.1%.
After the completion of the reaction, 7.27 g (91% yield) of poly (acrylic acid 2- (dimethylamino) ethyl-polyacrylic acid diblock polymer was obtained by drying.
After the carboxylic acid in the polymer was methyl esterified with trimethylsilyldiazomethane, the weight average molecular weight was 12,600 and PD was 1.13 by GPC analysis.

Example 3 [Synthesis of Poly (2- (dimethylamino) ethyl acrylate) -polyacrylate diblock polymer]
In a nitrogen-substituted glove box, 0.4 g (2.8 mmol) of 2- (dimethylamino) ethyl acrylate (DMAEA), 76.31 μl of ethyl-2-methyl-2-n-butylteranyl-propionate (BTEE) (0 .33 mmol), 2,2′-azobis (isobutyronitrile) (AIBN) 21.89 mg (0.13 mmol) and 0.4 g of methanol were reacted at 60 ° C. for 24 hours.
According to NMR analysis, the polymerization rate was 97%.
Moreover, it was the weight average molecular weight 840 and PD = 1.05 by TOF-MS analysis.
Next, 1.6 g (22.2 mmol) of acrylic acid (AA) and 1.6 g of methanol were added to 2- (dimethylamino) ethyl acrylate (initiator, used as a macroinitiator) obtained above. The reaction was carried out at 60 ° C. for 72 hours.
According to NMR analysis, the polymerization rate was 91.3%.
After completion of the reaction, drying was performed to obtain 1.85 g (yield 92%) of poly (acrylic acid 2- (dimethylamino) ethyl-polyacrylic acid diblock polymer).
After the carboxylic acid in the polymer was methyl esterified with trimethylsilyldiazomethane, the weight average molecular weight was 5,600 and PD was 1.14 by GPC analysis.

Example 4 [Synthesis of poly (2- (dimethylamino) ethyl acrylate) -polyacrylate diblock polymer]
In a nitrogen-substituted glove box, 0.1 g (0.7 mmol) of 2- (dimethylamino) ethyl acrylate (DMAEA), 19.08 μl of ethyl-2-methyl-2-n-butylteranyl-propionate (BTEE) (0 0.08 mmol), 2,2′-azobis (isobutyronitrile) (AIBN) 5.47 mg (0.03 mmol) and 0.1 g of methanol were reacted at 60 ° C. for 24 hours.
According to NMR analysis, the polymerization rate was 97%.
Moreover, it was the weight average molecular weight 840 and PD = 1.05 by TOF-MS analysis.
Next, 1.9 g (26.4 mmol) of acrylic acid (AA) and 1.9 g of methanol were added to 2- (dimethylamino) ethyl acrylate (initiator, used as a macroinitiator) obtained above. The reaction was carried out at 60 ° C. for 72 hours.
The polymerization rate was 96.1% by NMR analysis.
After completion of the reaction, the resultant was dried to obtain 1.92 g (yield 96%) of poly (acrylic acid 2- (dimethylamino) ethyl-polyacrylic acid diblock polymer.
After the carboxylic acid in the polymer was methyl esterified with trimethylsilyldiazomethane, the weight average molecular weight was 30,500 and PD was 1.14 by GPC analysis.

Example 5 Synthesis of poly (2- (dimethylamino) ethyl acrylate-polymethoxypolyethylene glycol monomethacrylate diblock polymer)
In a nitrogen-substituted glove box, 0.4 g (2.8 mmol) of 2- (dimethylamino) ethyl acrylate (DMAEA), 38.16 μl of ethyl-2-methyl-2-n-butylteranyl-propionate (BTEE) (0 .17 mmol), 2,2′-azobis (isobutyronitrile) (AIBN) 10.95 mg (0.07 mmol) and 0.4 g of methanol were reacted at 60 ° C. for 24 hours.
According to NMR analysis, the polymerization rate was 91%.
Moreover, it was the weight average molecular weight 1,760 and PD = 1.04 by TOF-MS analysis.
Next, polymethoxypolyethylene glycol monomethacrylate (EGA9: manufactured by Shin-Nakamura Chemical Co., Ltd., trade name M-) was added to the poly (2- (dimethylamino) ethyl acrylate) obtained above (initiator, used as a macroinitiator). 90G) 1.6 g (3.4 mmol) and 1.6 g of methanol were added and reacted at 60 ° C. for 72 hours.
According to NMR analysis, the polymerization rate was 99.8%.
After completion of the reaction, the resultant was dried to obtain 1.96 g (yield 98%) of 2- (dimethylamino) ethyl-polymethoxypolyethyleneglycol monomethacrylate diblock polymer polyacrylate.
It was a weight average molecular weight of 38,000 and PD = 1.39 according to GPC analysis in an aqueous system (eluent is 10 mmol / l lithium bromide aqueous solution).

Example 6 [Synthesis of Poly (2- (dimethylamino) ethyl) acrylate-polyacrylic acid random copolymer]
In a nitrogen-substituted glove box, 1.0 g (7.0 mmol) of 2- (dimethylamino) ethyl acrylate (DMAEA), 9.0 g (124.9 mmol) of acrylic acid (AA), ethyl-2-methyl-2 N-Butylterranyl-propionate (BTEE) 190.78 μl (0.83 mmol), 2,2′-azobis (isobutyronitrile) (AIBN) 54.74 mg (0.33 mmol) and methanol 10.0 g For 72 hours.
According to NMR analysis, the polymerization rate of 2- (dimethylamino) ethyl acrylate was 100%, and the polymerization rate of acrylic acid was 99%.
After completion of the reaction, drying was performed to obtain 9.9 g of polyacrylic acid 2- (dimethylamino) ethyl-polyacrylic acid random copolymer (yield 99%).
After the carboxylic acid in the polymer was methyl esterified with trimethylsilyldiazomethane, the weight average molecular weight was 16,000 and PD was 1.17 by GPC analysis.

Example 7
The polyacrylic acid 2- (dimethylamino) ethyl-polyacrylic acid diblock polymer 0.6 g obtained in Example 1 was neutralized with 7.5 g of a 1 mol / l aqueous sodium hydroxide solution (carboxylic acid groups in the polymer). 17.4 g of water was added. After the polymer was completely dissolved, 4.5 g of carbon black (MA100S: manufactured by Mitsubishi Chemical Corporation) was added, and pre-dispersion was performed at 600 rpm for 3 minutes using a TK-HOMO Mixer (manufactured by Primix Corporation). Thereafter, using a planetary pole mill (Fritsch Japan Co., Ltd.), 20 g of zirconia beads was used, and a dispersion treatment was performed for 30 minutes at a rotation speed range of 6 to obtain an aqueous pigment dispersion.

Example 8
0.03 g of the diblock polymer obtained in Example 1 was neutralized with 0.37 g of a 1 mol / l aqueous sodium hydroxide solution (the same number of carboxylic acid groups in the polymer), and 25.1 g of water was added. . After the polymer was completely dissolved, 4.5 g of carbon black (MA100S: manufactured by Mitsubishi Chemical Corporation) was added, and pre-dispersion was performed at 600 rpm for 3 minutes using a TK-HOMO Mixer (manufactured by Primix Corporation). Thereafter, using a planetary pole mill (Fritsch Japan Co., Ltd.), 20 g of zirconia beads was used, and a dispersion treatment was performed for 30 minutes at a rotation speed range of 6 to obtain an aqueous pigment dispersion.

Example 9
0.06 g of the diblock polymer obtained in Example 2 was neutralized with 0.67 g of a 1 mol / l aqueous sodium hydroxide solution (the same number of carboxylic acid groups in the polymer), and 24.77 g of water was added. . After the polymer was completely dissolved, 4.5 g of carbon black (MA100S: manufactured by Mitsubishi Chemical Corporation) was added, and pre-dispersion was performed at 600 rpm for 3 minutes using a TK-HOMO Mixer (manufactured by Primix Corporation). Thereafter, using a planetary pole mill (Fritsch Japan Co., Ltd.), 20 g of zirconia beads was used, and a dispersion treatment was performed for 30 minutes at a rotation speed range of 6 to obtain an aqueous pigment dispersion.

Example 10
0.06 g of the diblock polymer obtained in Example 3 was neutralized with 0.67 g of a 1 mol / l aqueous sodium hydroxide solution (the same number as the carboxylic acid group in the polymer), and 24.77 g of water was added. . After the polymer was completely dissolved, 4.5 g of carbon black (MA100S: manufactured by Mitsubishi Chemical Corporation) was added, and pre-dispersion was performed at 600 rpm for 3 minutes using a TK-HOMO Mixer (manufactured by Primix Corporation). Thereafter, using a planetary pole mill (Fritsch Japan Co., Ltd.), 20 g of zirconia beads was used, and a dispersion treatment was performed for 30 minutes at a rotation speed range of 6 to obtain an aqueous pigment dispersion.

Example 11
0.06 g of the diblock polymer obtained in Example 4 was neutralized with 0.79 g of a 1 mol / l aqueous sodium hydroxide solution (the same number of carboxylic acid groups in the polymer), and 24.65 g of water was added. . After the polymer was completely dissolved, 4.5 g of carbon black (MA100S: manufactured by Mitsubishi Chemical Corporation) was added, and pre-dispersion was performed at 600 rpm for 3 minutes using a TK-HOMO Mixer (manufactured by Primix Corporation). Thereafter, using a planetary pole mill (Fritsch Japan Co., Ltd.), 20 g of zirconia beads was used, and a dispersion treatment was performed for 30 minutes at a rotation speed range of 6 to obtain an aqueous pigment dispersion.

Example 12
After adding 0.6 g of the poly (acrylic acid 2- (dimethylamino) ethyl-polymethoxypolyethyleneglycol monomethacrylate diblock polymer obtained in Example 5 to 24.9 g of water and completely dissolving the polymer, carbon black ( MA100S: Mitsubishi Chemical Co., Ltd.) (4.5 g) was added, and pre-dispersion was performed at 600 rpm for 3 minutes using a TK-HOMO Mixer (manufactured by Primix Co., Ltd.). Thereafter, using a planetary pole mill (Fritsch Japan Co., Ltd.), 20 g of zirconia beads was used, and a dispersion treatment was performed for 30 minutes at a rotation speed range of 6 to obtain an aqueous pigment dispersion.

Example 13
The polyacrylic acid 2- (dimethylamino) ethyl-polyacrylic acid random copolymer 0.06 g obtained in Example 6 was neutralized with 0.67 g of a 1 mol / l aqueous sodium hydroxide solution (with carboxylic acid groups in the polymer). The same equivalent number), 24.77 g of water was added. After the polymer was completely dissolved, 4.5 g of carbon black (MA100S: manufactured by Mitsubishi Chemical Corporation) was added, and pre-dispersion was performed at 600 rpm for 3 minutes using a TK-HOMO Mixer (manufactured by Primix Corporation). Thereafter, using a planetary pole mill (Fritsch Japan Co., Ltd.), 20 g of zirconia beads was used, and a dispersion treatment was performed for 30 minutes at a rotation speed range of 6 to obtain an aqueous pigment dispersion.

Comparative Example 1 [Synthesis of Poly (2- (dimethylamino) ethyl) acrylate-polyacrylic acid random copolymer]
In a nitrogen-substituted glove box, 1.0 g (7.0 mmol) of 2- (dimethylamino) ethyl acrylate (DMAEA), 9.0 g (124.9 mmol) of acrylic acid (AA), 2,2′-azobis ( Isobutylonitrile) (AIBN) 100.00 mg (0.61 mmol) and 10.0 g of methanol were reacted at 60 ° C. for 72 hours.
According to NMR analysis, the polymerization rate of 2- (dimethylamino) ethyl acrylate was 100%, and the polymerization rate of acrylic acid was 100%.
After completion of the reaction, drying was performed to obtain 100 g (yield 100%) of poly (acrylic acid 2- (dimethylamino) ethyl-polyacrylic acid random copolymer.
After the carboxylic acid in the polymer was methyl esterified with trimethylsilyldiazomethane, the weight average molecular weight was 31,200 and PD was 2.87 by GPC analysis.

  The polyacrylic acid 2- (dimethylamino) ethyl-polyacrylic acid random copolymer 0.06 g obtained above was neutralized with 0.67 g of 1 mol / l sodium hydroxide aqueous solution (the same as the carboxylic acid group in the polymer, etc.) Amount), 24.77 g of water was added. After the polymer was completely dissolved, 4.5 g of carbon black (MA100S: manufactured by Mitsubishi Chemical Corporation) was added, and pre-dispersion was performed at 600 rpm for 3 minutes using a TK-HOMO Mixer (manufactured by Primix Corporation). Thereafter, using a planetary pole mill (Fritsch Japan Co., Ltd.), 20 g of zirconia beads was used, and a dispersion treatment was performed for 30 minutes at a rotation speed range of 6 to obtain an aqueous pigment dispersion.

Comparative Example 2 [Synthesis of polyacrylic acid]
In a glove box substituted with nitrogen, 2.0 g (27.8 mmol) of acrylic acid (AA), 38.16 μl (0.17 mmol) of ethyl-2-methyl-2-n-butylterranyl-propionate (BTEE), 2,2 '-Azobis (isobutyronitrile) (AIBN) (5.47 mg, 0.03 mmol) and methanol (2.0 g) were reacted at 60 ° C for 72 hours.
According to NMR analysis, the polymerization rate of acrylic acid was 99%.
After completion of the reaction, 1.9 g of polyacrylic acid (yield 95%) was obtained by drying.
After the carboxylic acid in the polymer was methyl esterified with trimethylsilyldiazomethane, the weight average molecular weight was 15,800 and PD was 1.24 by GPC analysis.

  0.06 g of the polyacrylic acid obtained above was neutralized with 0.83 g of a 1 mol / l aqueous sodium hydroxide solution (the same number as the carboxylic acid group in the polymer), and 24.61 g of water was added. After the polymer was completely dissolved, 4.5 g of carbon black (MA100S: manufactured by Mitsubishi Chemical Corporation) was added, and pre-dispersion was performed at 600 rpm for 3 minutes using a TK-HOMO Mixer (manufactured by Primix Corporation). Thereafter, using a planetary pole mill (Fritsch Japan Co., Ltd.), 20 g of zirconia beads was used, and a dispersion treatment was performed for 30 minutes at a rotation speed range of 6 to obtain an aqueous pigment dispersion.

Comparative Example 3 [Synthesis of polystyrene-polyacrylic acid diblock polymer]
In a nitrogen-substituted glove box, 1.6 g (15.0 mmol) of styrene, 152.58 μl (0.67 mmol) of ethyl-2-methyl-2-n-butylteranyl-propionate (BTEE), 2,2′-azobis ( Isobutyronitrile) (AIBN) 43.78 mg (0.27 mmol) and toluene 1.6 g were reacted at 60 ° C. for 24 hours.
According to NMR analysis, the polymerization rate was 98%.
Moreover, it was weight average molecular weight 2,670 and PD = 1.45 by GPC analysis.
Next, 11.4 g (89.0 mmol) of tert-butyl acrylate (t-BA) and 11.4 g of toluene were added to the polystyrene obtained above (used as an initiator and a macroinitiator), and 72 ° C. at 72 ° C. Reacted for hours.
According to NMR analysis, the polymerization rate was 99%.
The obtained polymer was hydrolyzed with concentrated sulfuric acid and then dried to obtain 8.8 g of a polystyrene-polyacrylic acid diblock polymer (yield: 73.3%).
After the carboxylic acid in the polymer was methyl esterified with trimethylsilyldiazomethane, the weight average molecular weight was 21,700 and PD was 1.14 by GPC analysis.

  0.06 g of the polystyrene-polyacrylic acid diblock polymer obtained above was neutralized with 0.67 g of a 1 mol / l sodium hydroxide aqueous solution (the same number as the carboxylic acid group in the polymer), and 24.77 g of water. Was added. After the polymer was completely dissolved, 4.5 g of carbon black (MA100S: manufactured by Mitsubishi Chemical Corporation) was added, and pre-dispersion was performed at 600 rpm for 3 minutes using a TK-HOMO Mixer (manufactured by Primix Corporation). Thereafter, using a planetary pole mill (Fritsch Japan Co., Ltd.), 20 g of zirconia beads was used, and a dispersion treatment was performed for 30 minutes at a rotation speed range of 6 to obtain an aqueous pigment dispersion.

Comparative Example 4 [Synthesis of 2- (dimethylamino) ethyl-co-methoxypolyethyleneglycol monomethacrylate random copolymer of polyacrylic acid by atom transfer radical polymerization ATRP method]
In a nitrogen-substituted glove box, 0.4 g (2.79 mmol) of 2- (dimethylamino) ethyl acrylate, 1.6 g (3.42 mmol) of methoxypolyethylene glycol monomethacrylate, 25. ethyl 2-bromoisobutyrate (EBIB). 22 μl (0.17 mmol), cuprous bromide (CuBr) 24.39 mg (0.17 mmol), 4,4′-dinonyl-2,2′-dipyridyl 138.999 mg (0.34 mmol) and methanol 2.0 g Was reacted at 60 ° C. for 72 hours.
According to NMR analysis, the polymerization rate of 2- (dimethylamino) ethyl acrylate was 88%, and the polymerization rate of methoxypolyethylene glycol monomethacrylate was 99%.
Moreover, it was weight average molecular weight 9,400 and PD = 1.35 by GPC analysis.
After the reaction, 2 g of activated alumina was added to the polymer solution and stirred at room temperature for 1 hour. The activated alumina was collected by filtration to obtain a yellow polymer solution. By drying the polymer solution, 1.9 g of 2- (dimethylamino) ethyl-co-methoxypolyethylene glycol monomethacrylate random copolymer of polyacrylic acid was obtained (yield: 95%).

Test example 1
The liquid after dispersion of Examples 7 to 13 and Comparative Examples 1 to 3 was analyzed. The particle size and particle size distribution were measured with a dynamic light scattering particle size distribution meter (FRAR-1000: manufactured by Otsuka Electronics Co., Ltd.) after 100-fold dilution. The viscosity was measured with an E-type viscometer (VISCOMETER TV-22: manufactured by Toki Sangyo Co., Ltd.). The results are shown in Table 1.

Test example 2
The polymer synthesized in Examples 1 to 4 and Comparative Example 4 was made into a 5 wt% methanol solution, and the total light transmittance (turbidimeter NDH2000: Nippon Denshoku Industries Co., Ltd.) and 500 nm transmittance (spectrophotometer U-3000). : Hitachi, Ltd.). The results are shown in Table 2. Since the pigment dispersants synthesized in Examples 1 to 6 are colorless and transparent, the color of the pigment can be expressed faithfully.

Test example 3
The liquid after dispersion of Examples 7 and 8 was analyzed. The results are shown in Table 3. There is almost no change in particle size before and after standing for 3 months, and the storage stability is very high.

Claims (8)

A resin composition containing a copolymer having the following characteristics (a) to (c).
(A) A copolymer comprising a monomer (A) having an amino group and a monomer (B) excluding the monomer (A).
(B) Total light transmittance at 5% solution of 95% or more, and transmittance at 500 nm of 95% or more.
(C) Molecular weight distribution 1.0 to 2.0. Monomer (A) is acrylamide, methacrylamide, 4-vinylaniline, aminomethyl (meth) acrylate, aminoethyl (meth) acrylate, anilinostyrenes, anilinophenylbutadienes, N-monosubstituted (meth) acrylamides, The resin composition according to claim 1, which is N, N-disubstituted aminoalkyl (meth) acrylate and N, N-disubstituted aminoalkyl (meth) acrylamide. Monomer (B) is (meth) acrylic acid ester, a cycloalkyl group-containing unsaturated monomers, carboxyl group-containing unsaturated monomers, (meth) hydroxy C ₂ -C ₁₂ alkyl esters of acrylic acid, (meth) polyethylene glycol acrylate -Derivative, caprolactone adduct of (meth) acrylic acid, hydroxyl group-containing ether monomer, hydroxyl group-containing ketone monomer, epoxy group-containing vinyl monomer, isocyanate group-containing vinyl monomer, vinyl group-containing vinyl monomer, sulfonic acid group-containing vinyl monomer, phosphoric acid The group-containing vinyl monomer, styrene-based monomer, aromatic unsaturated monomer, heterocyclic-containing unsaturated monomer, vinylamide, (meth) acrylamide-based monomer, α-olefin, dienes, and carboxylic acid vinyl ester. Tree Composition. The resin composition according to claim 1, wherein the copolymer is a copolymer obtained by polymerization using an organic tellurium compound-based polymerization initiator. Organic tellurium compound polymerization initiator,
(A) an organic tellurium compound represented by formula (1),
(B) a mixture of an organic tellurium compound represented by formula (1) and an azo polymerization initiator,
(C) A mixture of an organic tellurium compound represented by formula (1) and an organic ditellurium compound represented by formula (2), or (d) an organic tellurium compound represented by formula (1), an azo polymerization initiator. And the resin composition according to claim 4, which is a mixture of organic ditellurium compounds represented by formula (2):

(In the formula, R ¹ represents a C _{1 to} C ₈ alkyl group, an aryl group, a substituted aryl group or an aromatic heterocyclic group. R ² and R ³ represent a hydrogen atom or a C _{1 to} C ₈ alkyl group. R ⁴ represents an aryl group, a substituted aryl group, an aromatic heterocyclic group, an acyl group, an amide group, an oxycarbonyl group, or a cyano group.
(R ¹ Te) ₂ (2)
(In the formula, R ¹ is the same as above.) The dispersing agent containing the resin composition of any one of Claims 1-5. An aqueous pigment dispersion comprising water, a pigment and the dispersant of claim 6. A coating agent comprising the aqueous pigment dispersion of claim 7.