JP2003236359A - Dispersing agent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dispersing agent which is hardly hydrolyzed under an alkaline atmosphere, causes no viscosity variation of obtained slurry even with a limited amount of addition, is excellent in aging stability of the slurry viscosity, is excellent in various kinds of dispersion performance in the case of being used for manufacturing ink and further improves performance of the ink itself. <P>SOLUTION: The dispersing agent is made by containing a polymer which has a macromonomer (A) with an ethylenic unsaturated group expressed by a formula A-P1-X-(R<SP>1</SP>O)<SB>n</SB>R<SP>2</SP>and if necessary a compound (B) with an ethylenic group other than the component (A) as the building monomer units (provided that, in the formula, A is the ethylenic unsaturated group, P1 is a phenylene group optionally with a substituent, X is-R<SP>3</SP>O-(R<SP>3</SP>is a 1-7C alkylene group),-O-,- NHCOO-,-R<SP>4</SP>NHCOO(R<SP>4</SP>is a 1-7C alkylene group) or-CONH-, R<SP>1</SP>is a 2-4C alkylene group and R<SP>2</SP>is a hydrogen atom, an alkyl group or an aromatic group; n is an integer of 1-300). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a dispersant, and particularly to a dispersion for inorganic pigments, ceramic particles, mud, cement, pesticide granules, scale dispersion, detergent builder and water-based ink. It is useful as an agent and can be used in these technical fields.

[0002]

2. Description of the Related Art Conventionally, polyacrylic acid salts have been frequently used as polymer dispersants. However, a dispersant containing a polyacrylic acid salt has problems such as insufficient dispersibility, easy change over time, and poor salt resistance. To compensate for the insufficient performance, acrylic acid and polyoxyalkylene mono Salts and the like of copolymers with acrylates such as (meth) acrylates have been investigated (Japanese Patent Laid-Open No. 59-1931).
No. 26 publication).

[0003]

However, when used as a dispersant for inorganic pigments, mud and cement, a dispersant composed of a copolymer of acrylic acid and acrylate causes hydrolysis in an alkaline atmosphere. Since it is easy, the obtained slurry has a problem that the dispersibility of the slurry is lowered and the viscosity is easily increased, and the stability of the slurry viscosity with time is insufficient. In order to solve this problem, there is also a method of increasing the amount of the dispersant added, but if the amount of the dispersant added falls outside the appropriate amount of the dispersant, then the viscosity of the slurry will increase. It was something that had. Further, in the case of pesticide granules, the disintegration spreadability (dispersibility) in water is insufficient, in the case of scale dispersions, the scale dispersion performance is insufficient, and in the case of detergent builders, it does not cause mud stains. There is a problem that the dispersibility of dispersion is insufficient. On the other hand, the above-mentioned copolymer containing (meth) acrylic acid as a main component is also used as a copolymer used as a dispersant for an ink such as an aqueous ink. However, when a conventional dispersant is used as a dispersant for ink, it has a problem that the dispersibility, particularly the dispersion stability is insufficient, and as a result, the performance of the resulting ink itself is insufficient. It had a problem of becoming. The inventors of the present invention are unlikely to cause hydrolysis in an alkaline atmosphere, the viscosity of the obtained slurry does not change even when the amount added is small, the slurry viscosity is excellent in stability over time, and even when used in ink production, In order to find a dispersant which is excellent in various dispersion performances and can also improve the performance of the ink itself, the inventors have made earnest studies.

[0004]

The present inventors have found that a dispersant containing a polymer containing a macromonomer having an ethylenically unsaturated group having a specific structure as an essential constituent monomer unit is treated under an alkaline atmosphere. In the present invention, it was found that hydrolysis is unlikely to occur, viscosity change of the obtained slurry is unlikely to occur, stability of slurry viscosity with time is excellent, and that the performance of the ink itself can also be improved when used in the production of silk ink. Was completed. Hereinafter, the present invention will be described in detail. still,
In the present specification, acrylate or methacrylate is referred to as (meth) acrylate, acrylic acid or methacrylic acid is referred to as (meth) acrylic acid, and acrylamide or methacrylamide is referred to as (meth) acrylamide.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION 1. Polymer The polymer constituting the dispersant of the present invention (hereinafter simply referred to as a polymer) is a macromonomer (A) having an ethylenically unsaturated group represented by the general formula (1) and optionally an ethylenic A polymer having a compound (B) other than the component (A) having a saturated group as a constituent monomer unit is a constituent monomer unit. Each component will be described below.

1-1. Ethylenic fatigue expressed by general formula (1)
Macromonomer (A) having a valence group The polymer in the present invention essentially comprises a macromonomer (A) having an ethylenically unsaturated group represented by the following general formula (1) (hereinafter simply referred to as component (A)) It is a monomer unit. According to the component (A), the polymer obtained is difficult to decompose under alkaline conditions, and the above problems can be solved.

[0007]

Embedded image A-P1-X- (R ¹ O) _n R ² ... (1)

[In the above general formula (1), A is an ethylenically unsaturated group, Pl is a phenylene group which may have a substituent, X is —R ³ O— (R ³ is , Carbon number 1
7 alkylene group), —O—, —NHCOO—, —R ⁴
NHCOO- (R ⁴ is an alkylene group having 1 to 7 carbon atoms) or -CONH-, R ¹ is an alkylene group having 2 to 4 carbon atoms, and R ² is a hydrogen atom, an alkyl group or an aromatic group. n is an integer of 1 to 300. ]

In the above formula (1), A is an ethylenically unsaturated group, specifically, a vinyl group, a 2-propenyl group,
Examples thereof include an isopropenyl group, a hydroxypropenyl group, an allyl group, a methallyl group, an isobutenyl group and a hydroxyisobutenyl group.

Among these, a vinyl group, a 2-propenyl group and an isopropenyl group are preferable, and a vinyl group is more preferable, from the viewpoint of excellent polymerizability with the following component (B).

Pl is a phenylene group which may have a substituent, and specific examples thereof include p-phenylene group, m-phenylene group, and a mixture thereof, and preferably p-phenylene group. Examples of the substituent for the phenylene group include a hydroxyl group, a carboxyl group and an alkylene group.

X is --R ³ O-- (R ³ is an alkylene group having 1 to 7 carbon atoms), --O--, --NHCOO--, --R ⁴ NH.
COO- (R ⁴ is an alkylene group having 1 to 7 carbon atoms) or-
CONH-. When X is other than these, for example, an ester bond, the resulting dispersant causes decomposition under alkaline conditions. X is —R ³ O
-, - O-and -R ⁴ NHCOO- is preferred from the viewpoint of more excellent alkali resistance, -R ³ O-are more preferred.

R ³ is an alkylene group having 1 to 7 carbon atoms. The alkylene group may be linear or branched. When the alkylene group has 8 or more carbon atoms, the hydrophobic part becomes strong and the dispersibility deteriorates. R
³ is preferably an alkylene group having 1 to 4 carbon atoms, and more preferably an alkylene group having 1 to 2 carbon atoms.

R ⁴ is an alkylene group having 1 to 7 carbon atoms. The alkylene group may be linear or branched. When the alkylene group has 8 or more carbon atoms, the hydrophobic part becomes strong and the dispersibility deteriorates. R
^{4, although} it depends on the balance with the amount of hydrophilic groups in the polymer, is preferably an alkylene group having 1 to 5 carbon atoms,
More preferably, it is an alkylene group having 2 to 4 carbon atoms.

R ¹ is an alkylene group having 2 to 4 carbon atoms, preferably 2 to 3 carbon atoms, and more preferably 2 carbon atoms. When the number of carbon atoms is 5 or more, the hydrophobicity becomes strong and the dispersibility decreases. The alkylene group may be linear or branched.

R ² is a hydrogen atom, an alkyl group or an aromatic group. Examples of the alkyl group include a linear alkyl group, a branched alkyl group and a cyclic alkyl group. The straight-chain alkyl group or the branched alkyl group has 1 to 8 carbon atoms.
The alkyl group having 1 to 4 carbon atoms is preferable, and the alkyl group having 1 to 2 carbon atoms is more preferable. With an alkyl group having 9 or more carbon atoms, the hydrophobicity of the polymer may be increased and the dispersibility may be reduced. Examples of the cyclic alkyl group include a cyclohexyl group and the like. Examples of the aromatic group include phenyl and benzyl. R ² is preferably a hydrogen atom and a linear or branched alkyl group having 1 to 8 carbon atoms.

N is an integer of 1 to 300. n is a factor that affects the dispersibility of the resulting dispersant, and long-chain ones tend to have excellent stability over time, and are preferably 2-10.
It is 0, more preferably 3 to 40.

As the component (A), the above-mentioned A, Pl,
X, R¹, R²And n satisfying n
Can be used, but A is a vinyl group or a propenyl group, X
Is -R ³O- or -O-, R²Is a hydrogen atom or a carbon number of 1 to
Those having 8 alkyl groups are preferred. These preferred (A)
Specific examples of the components are given below.

○ A is a vinyl group, X is —R ³ O—, and R ² is a hydrogen atom. Poly (oxyethylene) vinylbenzyl ether, poly (oxypropylene) vinylbenzyl ether, poly (oxyethylene) vinylphenylethyl. Examples thereof include ether and poly (oxypropylene) vinylphenylethyl ether.

◯ A is a vinyl group, X is —R ³ O—, and R ² is an alkyl group having 1 to 8 carbon atoms Methyl poly (oxyethylene) vinyl benzyl ether, ethyl poly (oxyethylene) vinyl benzyl ether, methyl poly ( Oxypropylene) vinyl benzyl ether, ethyl poly (oxypropylene) vinyl benzyl ether, methyl poly (oxyethylene) vinyl phenyl ethyl ether, ethyl poly (oxyethylene)
Examples thereof include vinyl phenyl ethyl ether, methyl poly (oxypropylene) vinyl phenyl ethyl ether and ethyl poly (oxy propylene) vinyl phenyl ethyl ether.

○ A is an isopropenyl group and X is --R ³ O
Examples of —, R ² being a hydrogen atom include poly (oxyethylene) isopropenylbenzyl ether and poly (oxypropylene) isopropenylbenzyl ether.

○ A is an isopropenyl group and X is --R ³ O
Examples of an alkyl group in which R ² has 1 to 8 carbon atoms include methylpoly (oxyethylene) isopropenylbenzyl ether, ethylpoly (oxyethylene) isopropenylbenzyl ether, and methylpoly (oxypropylene) isopropenylbenzyl ether.

◯ A is a vinyl group, X is —O—, and R ² is a hydrogen atom. Tetra (oxyethylene) vinylphenyl ether, poly (oxyethylene) vinylphenyl ether, tetra (oxypropylene) vinylphenyl ether and poly. (Oxypropylene) vinyl phenyl ether and the like can be mentioned.

◯ A is a vinyl group, X is —O—, and R ² is an alkyl group having 1 to 8 carbon atoms Methyl tetra (oxyethylene) vinyl phenyl ether, ethyl tetra (oxyethylene) vinyl phenyl ether, propyl tetra ( Oxyethylene) vinyl phenyl ether, n-butyl tetra (oxyethylene) vinyl phenyl ether, n-pentyl tetra (oxyethylene) vinyl phenyl ether, methyl tetra (oxypropylene) vinyl phenyl ether, ethyl tetra (oxypropylene) vinyl phenyl ether, propoxy Tetra (oxypropylene) vinyl phenyl ether, n-butyl tetra (oxypropylene) vinyl phenyl ether, n-pentaxy tetra (oxypropylene) vinyl phenyl ether, methyl poly (o Shiechiren) vinyl phenyl ether, Echirupori (oxyethylene) vinyl phenyl ether, methylpoly (oxypropylene) vinyl phenyl ether and Echirupori (oxypropylene) and vinyl phenyl ether.

○ A is an isopropenyl group, X is --O--, R
Examples in which ² is a hydrogen atom include poly (oxyethylene) isopropenyl phenyl ether and poly (oxypropylene) isopropenyl phenyl ether.

○ A is an isopropenyl group, X is --O--, R
² is an alkyl group having 1 to 8 carbon atoms Methyl poly (oxyethylene) isopropenyl phenyl ether, ethyl poly (oxyethylene) isopropenyl phenyl ether, methyl poly (oxypropylene)
Examples include isopropenyl phenyl ether and ethyl poly (oxypropylene) isopropenyl phenyl ether.

The component (A) can be produced by a known method. For example, Polymer Journal Vol. 17, 7
Issue 827-839 [Polymer Journal, Vol.17.No7, p8
27-839 (1985)] and the like.

1-2. Compound having an ethylenically unsaturated group
(B) The compound other than the component (A) having an ethylenically unsaturated group in the present invention (hereinafter simply referred to as the component (B)), various compounds can be used, an ethylenically unsaturated group and a hydrophilic group And a compound (B-2) having an ethylenically unsaturated group and a hydrophobic group. Each component will be described below.

1-2-1. Ethylenically unsaturated group and hydrophilic group
As the compound (B-1) having a compound having an ethylenically unsaturated group and a hydrophilic group [hereinafter simply referred to as the component (B-1)], a low molecular weight compound is preferable. For example, a compound having an ethylenic unsaturation and a carboxyl group (hereinafter referred to as an unsaturated carboxylic acid), a compound having an ethylenic unsaturated group and a sulfonic acid group (hereinafter referred to as an unsaturated sulfonic acid), a cationic group and an ethylenic unsaturated Examples thereof include a compound having a group (hereinafter referred to as a cationic unsaturated compound), a hydroxyl group-containing (meth) acrylate and (meth) acrylamide.

Examples of the unsaturated carboxylic acid include (meth) acrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride, maleic acid half ester (maleic acid monobutyl ester). , Maleic acid monoethylcarbitol ester, etc.) and fumaric acid half ester (fumaric acid monobutyl ester, fumaric acid monoethylcarbitol ester, etc.)
Etc., or their anhydrides and the like. As the unsaturated carboxylic acid, a salt can be used, and examples thereof include alkali metal salts, alkaline earth metal salts, ammonium salts and organic amine salts of these unsaturated carboxylic acids. Specific examples of salts of the unsaturated carboxylic acid salts include lithium salts, sodium salts and potassium salts as alkali metal salts; calcium salts and magnesium salts as alkaline earth metal salts; ammonium salts as ammonium salts. Examples of salts and tetraoctyl ammonium salts; and organic amine salts include alkanol amine salts, polyalkylene polyamine salts or their derivatives (alkylated products, alkylene oxide adducts) salts, lower alkyl amine salts and the like.

As the unsaturated sulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 3- (meth)
Acrylamide-2-hydroxypropanesulfonic acid Vinylsulfonic acid, allylsulfonic acid, methallylsulfonic acid, styrenesulfonic acid, α-methylstyrenesulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, sulfopropyl (meth) acrylate, 2-hydroxy-3- (meth) acryloxypropane sulfonic acid,
3- (meth) acryloyloxyethanesulfonic acid, 3
-(Meth) acryloyloxy-2-hydroxypropanesulfonic acid, 2-hydroxy-3- (meth) acryloxyp, 2- (meth) acryloylamino-2,2-dimethylethanesulfonic acid and alkyl (having 3 to 1 carbon atoms)
8) (Meth) allyl sulfosuccinic acid and the like. As these unsaturated sulfonic acids, salts can also be used, and examples thereof include alkali metal salts, alkaline earth metal salts, ammonium salts and organic amine salts. Specific examples of the salts include the same as those mentioned above.

Examples of the cationic unsaturated compound include dialkylaminoalkyl (meth) acrylates such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate and diethylamino-2-hydroxypropyl (meth) acrylate, or dimethylaminopropyl. Tertiary amine salts such as dialkylaminoalkyl (meth) acrylamide hydrochlorides or sulfates such as (meth) acrylamides; dialkylaminoalkyl (meth) acrylates or methyl chloride adducts of dialkylaminoalkyl (meth) acrylamides such as Examples include quaternary salts.

Examples of the hydroxyl group-containing (meth) acrylate include hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate.

Examples of (meth) acrylamide include (meth) acrylamide and N-methylol (meth) acrylamide.

The component (B-1) in the polymer may be appropriately selected depending on the type of dispersoid and dispersion medium to be applied, has a strong interaction with the dispersoid, and is compatible with the dispersion medium to be applied. It is preferable that it is excellent. Especially for inorganic pigments, for ceramic particles, for mud, for cement, for agrochemical granules, for scale dispersion and for detergent builder, as the component (B-1), unsaturated carboxylic acid, unsaturated sulfonic acid and A cationic unsaturated compound is preferable, and an unsaturated carboxylic acid is more preferable because it serves as a dispersant having excellent dispersibility.

1-2-2. Ethylenically unsaturated group and hydrophobic group
Compound (B-2) having a compound having an ethylenically unsaturated group and a hydrophobic group [hereinafter simply referred to as (B-2) component], various compounds can be used, an ethylenically unsaturated group and an aromatic group (Hereinafter referred to as an aromatic unsaturated compound), an aliphatic ethylenically unsaturated compound, an alicyclic ethylenically unsaturated compound, and an alkyl (meth) acrylate.

As the aromatic unsaturated compound, styrene,
α-methylstyrene, vinyltoluene, styrenes such as hydroxystyrene, halogen substituted styrenes such as vinylnaphthalene and dichlorostyrene, and the like,

As the aliphatic ethylenically unsaturated compound,
Those having 2 to 20 carbon atoms are preferable and examples thereof include ethylene, propylene, butene, isobutylene, pentene, heptene, diisobutylene, octene, dodecene, octadecene, butadiene and isoprene.

The alicyclic ethylenically unsaturated compound preferably has 5 to 15 carbon atoms, and cyclopentadiene,
Examples include pinene, limonene, indene, bicyclopentadiene and ethylidene norbornene.

As the alkyl (meth) acrylate,
Those having an alkyl group having 1 to 50 carbon atoms are preferable,
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth)
Examples thereof include acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate and eicosyl (meth) acrylate.

1-3. Polymer production method The polymer in the present invention is a homopolymer of the component (A),
Alternatively, the component (A) and the component (B) are used as constituent monomer units. In the polymer, the copolymerization ratio of the components (A) and (B) when the component (B) is copolymerized may be appropriately set according to the intended use of the dispersant. A dispersant, an inorganic pigment dispersant described below, a ceramic particle dispersant,
Mud dispersant, cement dispersant, agricultural chemical granule dispersant,
When used as a dispersant for scale dispersion and a dispersant for detergent builders, component (A): component (B) = 0.1: 99.9.
-80: 20 (mass ratio) is preferable. In this case, if the ratio of the component (A) is less than 0.1, the dispersion improving effect due to the copolymerization of the component (A) may not be observed, while if it exceeds 80, the component (B) becomes Copolymerization may become difficult. On the other hand, when the dispersant is used as a pigment dispersant for an ink described later, (A) component: (B) component = 5: 95-9
9: 1 (mass ratio) is preferable. In this case, when the ratio of the component (A) is less than 5, the effect of improving the dispersion due to the copolymerization of the component (A) may not be observed.

Preferred combinations of the component (B) in the polymer are as follows. When the dispersant is used as a dispersant for inorganic pigments, a dispersant for ceramic particles, a dispersant for mud, a dispersant for cement, a dispersant for agricultural chemical granules, a dispersant for scale dispersion and a dispersant for detergent builder, which will be described later. Is preferably a polymer containing the component (A) and the component (B-1) as essential constituent monomer units. In this case, the component (B-2) may further be a constituent monomer, if necessary. (B
-As a preferable ratio when the component (2) is used in combination, the obtained polymer is within the range of maintaining water solubility, and specifically, with respect to the total amount of the component (A) and the component (B-1). It is 0 to 40% by mass.

When the dispersant is used as a pigment dispersant for ink described below, a polymer having the component (A) and the component (B-2) as essential constituent monomer units is preferable. In this case, the component (B-1) may further be a constituent monomer, if necessary. Further when the component (B-1) is used in combination, the component (B-1) is preferably obtained as a polymer, specifically (A).
It is 0 to 40 mass% with respect to the total amount of the component and the component (B-2).

The polymer can be produced by a usual polymerization method using the above-mentioned component (A) and, if necessary, the component (B). The polymerization method may be any of solution polymerization, emulsion polymerization, suspension and bulk polymerization, but solution polymerization, emulsion polymerization and suspension polymerization are preferable, and solution polymerization is particularly preferable.

Solvents for solution polymerization include water; alcohols such as methanol, ethanol and isopropanol; ketones such as acetone and methyl isobutyl ketone; ethers such as tetrahydrofuran; aliphatic hydrocarbons such as hexane and heptane; toluene and xylene. And aromatic hydrocarbons; halogenated solvents such as ethylene dichloride; and mixtures thereof. Among these, preferred are water and a mixed solvent of isopropanol and water. Temperature below the boiling point of the polymerization solution under normal pressure,
The boiling point of the polymerization solution under normal pressure, the temperature above the boiling point of the polymerization solution under pressure, and the like are included. Preferred is a method in which polymerization is carried out under pressure at a boiling point of the polymerization solution or higher. The specific polymerization temperature is usually 20 to 200 ° C., preferably 60 to 15
It is 0 ° C. There are no particular restrictions on the types of emulsifiers and dispersants used, and known ones can be used. The polymerization initiator is of a type that generates radical free radicals to initiate the polymerization, for example, persulfates such as sodium persulfate and potassium persulfate; 2,2′-azobisisobutyronitrile, 2, 2'-azobis (2,4-
Dimethylvaleronitrile), 2,2'-azobis (2-
Methyl butyronitrile), 1,1′-azobis (cyclohexane-1-arbonitrile), 2,2′-azobis (2,4,4-trimethylpentane), dimethyl 2,
2'-azobis (2-methylpropionate), 2,
2'-azobis [2- (hydroxymethyl) propionitrile] and 1,1'-azobis (1-acetoxy-1)
-Phenylethane) and other azo compounds; dibenzoyl peroxide, dicumyl peroxide, bis (4-t-
Organic peroxides such as butylcyclohexyl) peroxydicarbonate, benzoyl peroxide, lauroyl peroxide and persuccinic acid; and inorganic peroxides such as perborate and hydrogen peroxide can be used. Further, a redox type initiator or the like combined with a reducing agent can be used. Examples of the reducing agent used for the redox type initiator include ascorbic acid (salt), rongalite, hypophosphorous acid (salt), sulfurous acid (salt), bisulfite (salt), ferrous iron salt and the like. These may be used in combination of two or more. The amount of radical polymerization initiator added is based on the total amount of monomers.
It is usually 0.01 to 20% by mass, preferably 0.05.
Is about 5% by mass. Further, a chain transfer agent can be used if necessary. Examples of the chain transfer agent include alcohol compounds such as isopropyl alcohol, mercapto compounds such as mercaptopropionic acid and 2-mercaptoalcohol, and thiol compounds such as thiobenzoate. These may be used in combination of two or more. The amount of chain transfer agent added is usually 0.00 based on the total amount of monomers.
1 to 100% by mass, preferably 0.01 to 50% by mass,
It is particularly preferably 0.1 to 20% by mass.

The weight average molecular weight of the polymer is preferably 1,000 to 100,000, more preferably 2,000 to 50,000, from the viewpoint of excellent dispersibility.
Particularly preferably, it is 3,000 to 20,000. 1,
If it is less than 000, the dispersing effect may not be exhibited in some cases, and if it exceeds 100,000, the thickening effect becomes dominant and the dispersing effect may not be seen. The weight average molecular weight in the present invention means the molecular weight in terms of sodium polyacrylate as measured by aqueous gel permeation chromatography.

When the polymer in the present invention has a free acidic group such as a carboxyl group and a sulfonic acid group as the component (B-1), it can be used as a neutralizing salt,
When added to the object to be dispersed, the shock of addition that an insoluble component is generated due to a sudden change in pH can be mitigated, and the compatibility with the dispersion medium can be improved, which is preferable. Examples of the salt in this case include an alkali metal salt, an alkaline earth metal salt, an ammonium salt, an organic amine salt and the like, and specific examples thereof include the same ones as described above. As the method for producing the neutralized salt, a method of polymerizing using a salt of an unsaturated carboxylic acid or an unsaturated sulfonic acid as the component (B-1), and
Examples include a method of copolymerizing the components (A) and (B-1), and then neutralizing the free acidic group in the copolymer with an alkali compound. The alkali compound used for the neutralization may be an alkali compound of a target salt, for example, in the case of an alkali metal salt or an alkaline earth metal salt, hydroxides of these metals and the like can be mentioned. When it is an ammonium salt, it is ammonia, and when it is an organic amine salt, it is the corresponding organic amine.

The ratio of the neutralized salt of the polymer is important because it can control the added shock and the compatibility with the dispersion medium, and the optimum value may be appropriately set depending on the pH of the dispersion medium and the like. When the dispersion medium is an aqueous solvent, the compatibility is excellent, and the dispersibility of the dispersoid is excellent.
It is preferably 1%, more preferably 50 to 10
0 mol%, more preferably 70 to 100 mo
1%.

2. Dispersant The dispersant of the present invention comprises the polymer as a constituent component. As the usage form of the dispersant of the present invention, a polymer powder can be used as it is, or an aqueous solution in which the polymer is dissolved (hereinafter referred to as a dispersant aqueous solution) can be used. When used as an aqueous dispersant solution, the aqueous solvent may be water or a water-soluble organic solvent (eg, methyl alcohol, ethyl alcohol, ethylene glycol, etc.).
And a mixed solution thereof.

The dispersant of the present invention can be used for various purposes, for example, an inorganic pigment dispersant, an organic pigment dispersant,
Examples include a dispersant for ceramic particles, a dispersant for mud, a dispersant for cement, a dispersant for pesticide granules, a dispersant for scale dispersion, and a dispersant for detergent builders. Specific examples of each use include, for inorganic pigments, wet grinding for calcium carbonate, dry grinding for calcium carbonate, light calcium carbonate manufacturing process, recycled sludge and causticized light calcium carbonate manufacturing process dispersant, etc. Can be mentioned.
Examples of organic pigments include pigment dispersants for water-based inks. Examples of the ceramic particles include those for the ferrite manufacturing process. Examples of the mud include dispersants for drilling mud, sewage sludge cakes, and purified water sludge cakes. Examples of cements include dispersants for mortar and dispersants for concrete. Examples of pesticide granules include pesticide granule dispersants such as insecticides, fungicides, herbicides and acaricides. Examples of scale dispersants include scale dispersants such as calcium carbonate, calcium phosphate and silica. Examples of detergent builders include detergent-added dispersants such as laundry powder detergents, liquid laundry detergents, tableware powder detergents, tableware liquid detergents, bleaching powder detergents and bleaching liquid detergents.

Inorganic pigments applicable as the inorganic pigment dispersant include calcium carbonate, clay, kaolin, talc,
Examples include satin white, titanium oxide, zinc oxide, carbon black, coal, alumina, aluminum hydroxide, magnesium hydroxide, silica, red iron oxide, calcium phosphate, barium sulfate and gypsum.

Organic pigments applicable as the dispersant for organic pigments include quinacridone pigments, quinacridone quinone pigments, dioxazine pigments, phthalocyanine pigments, anthrapyrimidine pigments, ansanthuron pigments, indanthrone pigments, flavans. Threon pigments, perylene pigments, diketopyrrolopyrrole pigments, perinone pigments, quinophthalone pigments, anthraquinone pigments, thioindigo pigments, benzimidazolone pigments, isoindolinone pigments, azomethine pigments and azo pigments. Etc.

The dispersant of the present invention can be used according to a usual method, such as adding a dispersant, a dispersant and water, or an aqueous dispersant solution to a liquid containing a dispersoid, followed by stirring and mixing. A method of adding a powdery dispersoid or a liquid containing a dispersoid to an aqueous solution of a dispersant, and stirring / mixing the same, may be mentioned.
As another method, there is a method in which a dispersant is added at the same time as wet pulverization of raw ore powder or coarse particles to prepare a dispersion. For the stirring / mixing operation, a commonly used stirring device such as a high speed disperser, a homomixer, a ball mill and a concrete mixer can be used.

The use ratio of the dispersant of the present invention may be appropriately set depending on the use and the object to be dispersed. When a powder such as calcium carbonate is dispersed in an aqueous solvent, the ratio of the solid content of the dispersant to the weight of the powder is 0.001 to 20.
Mass% is preferable, and 0.05 to 10 mass% is more preferable. If it is less than 0.001%, the dispersing effect is insufficient, and if it exceeds 20% by mass, the viscosity of the slurry may increase due to the aggregating action.

When the water dispersion of an inorganic pigment such as calcium carbonate or the object to be dispersed such as excavated sludge contains water, the ratio of the solid content of the dispersant to the weight of the solid content of the object to be dispersed is 0.01 to 10. Mass% is preferable, more preferably 0.01 to 5 mass%, particularly preferably 0.05 to.
It is 2% by mass. If it is less than 0.01%, the dispersing effect may be insufficient, and if it exceeds 5% by mass, the aggregation effect may be exhibited and the viscosity may increase. In this case, the proportion of the dispersoid in the object to be dispersed is preferably 10 to 90% by mass.

The dispersant of the present invention can be preferably used as a dispersant for calcium carbonate, a dispersant for mud, and a pigment dispersant for water-based inks because it has a particularly excellent dispersibility. Hereinafter, each dispersant will be described.

2-1. Dispersant for Calcium Carbonate When the dispersant of the present invention is used as a dispersant for calcium carbonate, preferable addition ratio and usage method may be the same as those described above. The calcium carbonate after dispersion can be applied to, for example, a paper making process, and specifically, it can be used as a pigment for paper coating and for internal addition in the paper making process.

2-2. Dispersant for mud When the dispersant of the present invention is used as a dispersant for mud, applicable mud includes purified water sludge, sewage sludge and completed soil, and water-soluble polymers such as carboxymethyl cellulose and cement. Etc. may be included. Examples of constituents of the mud include ferrite, zirconia, bentonite, attapulgite, sepiolite, sericite, and diatomaceous earth.

The mixing ratio of the dispersant to the mud water containing mud is preferably 0.01 to 10% by mass, more preferably 0.05 to 10% by mass as the solid content of the dispersant with respect to the total solid content of the muddy water composition. It is 5% by mass. If it is less than 0.01% by mass, the effect of preventing deterioration of muddy water dispersion may be reduced due to seawater and other electrolytes such as cement, etc. 10% by mass
If it exceeds, the effect obtained by blending may not be obtained, which may be uneconomical.

As a method for blending with mud water containing mud, inorganic clays, water-soluble polymer and the additive of the present invention are simultaneously added to kneading water, or inorganic clays, water-soluble polymer and the like are previously mixed with water. And the additives of the present invention are added after swelling.

A method for obtaining an aqueous dispersion of mud by using the dispersant of the present invention may be a usual dispersion method, for example, adding mud to the aqueous solution of the dispersant of the present invention and stirring The method of mixing is mentioned. Further, as another method, there is a method of adding the dispersant of the present invention at the same time as wet pulverizing a water-containing cake of mud or coarse particles to form a dispersion. To give an example of a specific method for applying the dispersant of the present invention to mud, the dispersant of the present invention, an inorganic clay, and in some cases a water-soluble polymer is mixed with water to form a mud composition. The ground is excavated using an excavator while preparing and circulating or accumulating this in the excavation part. In this case, the mud composition always fills the inside of the excavated portion, absorbs frictional heat, functions such as heat radiation and lubrication, and carries out the excavated earth and sand to the ground to advance excavation and form an impermeable mud wall. Prevent collapse of borehole walls. After the predetermined excavation is completed, the steel frame is usually put in and concrete is poured from the bottom to collect mud water from the excavation trench while filling the excavation part with concrete to construct a pile or wall. The drilling mud replaced with concrete is returned to the tank and reused. In this case, in addition to the dispersant of the present invention, an antifoaming agent (such as a silicone-based surfactant), a dissolution accelerator (such as ethylene glycol, diethylene glycol, or polyethylene glycol), a dispersion peptizer (sodium nitrohumate, tannic acid, Ligninic acid, lignin sulfonic acid, condensed phosphate, etc.), a deterioration inhibitor, and an antiseptic agent can be appropriately used in combination.

2-3. Pigment Dispersant for Aqueous Inks When the dispersant of the present invention is used as a pigment dispersant for aqueous ink, the components to be used include a pigment and an aqueous medium in addition to the above dispersants. Examples of the pigment include carbon black and the above-mentioned inorganic and organic pigments.
As the aqueous medium, a mixed solvent of water and a water-soluble organic solvent is suitable. The water is preferably ion-exchanged water (deionized water). As the water-soluble organic solvent, methyl alcohol, ethyl alcohol, n-propyl alcohol,
Isopropyl alcohol, n-butyl alcohol, se
alkyl alcohols having 1 to 4 carbon atoms such as c-butyl alcohol and tert-butyl alcohol; amides such as dimethylformamide and dimethylacetamide; ketones or keto alcohols such as acetone and diacetone alcohol; ethers such as tetrahydrofuran and dioxane; polyethylene; Polyalkylene glycol such as glycol and polypropylene glycol; 2 to 6 alkylene groups such as ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, 1,2,6-hexanetriol / thiodiglycol, hexylene glycol and diethylene glycol Alkylene glycol containing carbon atoms; glycerin, ethylene glycol monomethyl (or ethyl) ether, diethylene glycol methyl (Or ethyl) ether and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl (or ethyl) ether; and N-
Methyl-2-pyrrolidone, 2-pyrrolidone and 1,3-
Dimethyl-2-imidazolidinone and the like can be mentioned. Among these water-soluble organic solvents, polyhydric alcohols such as diethylene glycol and lower alkyl ethers of polyhydric alcohols such as triethylene glycol monomethyl (or ethyl) ether are preferable.

The aqueous ink contains a surfactant, an antifoaming agent, an antiseptic, an antisettling agent, a chelating agent, a thickener, an anticorrosive, a dye and the like as other components besides the dispersant, the pigment and the aqueous medium. You may. As the surfactant, anionic surfactants such as fatty acid salts, higher alcohol sulfate ester salts, liquid fatty acid sulfate ester salts and alkylallyl sulfonates; and polyoxyethylene alkyl ethers, polyoxyethylene alkyl esters,
Nonionic surfactants such as polyoxyethylene sorbitan alkyl esters, acetylene alcohol and acetylene glycol can be mentioned.

The dispersant may be used according to a usual method, for example, the dispersant of the present invention, the pigment and water are stirred and mixed, and the mixture is subjected to a forced crusher such as a bead mill. A method of further mixing may be mentioned. The addition ratio of the dispersant is preferably 0.1 to 20 mass% in the aqueous ink, and the pigment ratio is 1 to 50 mass%.
Is preferable, the range of 3 to 20% by mass is more preferable, the ratio of the water-soluble organic solvent is preferably 3 to 50% by mass, and the range of 3 to 40% by mass is more preferable, and the ratio of water is , Preferably in the range of 10 to 90% by mass, and 30
The range of -80 mass% is more preferable. The pH of the aqueous ink is preferably in the range of 7-10. By setting the pH within this range, the solubility of the pigment dispersant can be improved and the storage stability can be improved. Moreover, it is possible to suppress the corrosion of the members of the apparatus (for example, an inkjet recording apparatus) to which the water-based ink is applied.

[0065]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples. In the following, "%" means
"Mass%" means "parts" means "parts by mass". The component (A) used in Production Examples is shown in Table 1 below.

[0066]

[Table 1]

[Production Example 1] 275 g of water was charged in a 2000 mL round-bottomed flask equipped with a stirrer, a reflux condenser, a thermometer and a dropping port, and the reaction solution temperature was kept at 80 ° C.
After that, 125g of water, 500g of acrylic acid and 1 of A-1
The monomer aqueous solution prepared by mixing 5 g was dropwise added by a metering pump in 4.0 hours. At the same time, 2.5 g of 20% sodium persulfate as a polymerization initiator and 112 g of 25% sodium hypophosphite as a chain transfer agent were added dropwise by separate metering pumps in 4.0 hours.
After continuous feeding, aging for 1 hour and then cooling while cooling 48
It was neutralized with 520 g of% NaOH (neutralization rate 90 mo%). The pH of the reaction solution was 6.7. The weight average molecular weight (hereinafter abbreviated as Mw) of the obtained copolymer was measured by gel permeation chromatography (GPC). The condition of GPC is HLC8020 system manufactured by Tosoh Corporation, and the column used is G4000PWxl + G3000.
PWxl + G2500PWxl [manufactured by Tosoh Corporation], the eluent is 0.1M NaCl + phosphate buffer (pH
7), a calibration curve was created using Na polyacrylate (Soka Kagaku). The measurement results are shown in Table 2.

[0068]

[Table 2]

[Production Examples 2 to 4] In Production Example 1,
Instead of A-1 as the component (A), A-2 and A-, respectively.
A copolymer was produced in the same manner as in Production Example 1 except that No. 3, A-4 was used. About the obtained copolymer, Production Example 1
Mw was measured in the same manner as in. The results are shown in Table 2 together with the neutralization rate.

MANUFACTURING EXAMPLE 5 In the same manner as in Manufacturing Example 1 except that A-2 was used as the component (A) in place of A-1 and 46 g of 25% sodium hypophosphite was used,
A copolymer was produced. The Mw of the obtained copolymer was measured by the same method as in Production Example 1. The results are shown in Table 2 together with the neutralization rate.

[Production Example 6] In Production Example 5, 25 g of sodium hypophosphite was changed to 38 g and 48% NaOH of 3 was added.
Production Example 5 except that 50 g was used for neutralization (neutralization rate 60 mo%)
A copolymer was produced in the same manner as in. The Mw of the obtained copolymer was measured by the same method as in Production Example 1. The results are shown in Table 2 together with the neutralization rate.

MANUFACTURING EXAMPLE 7 The procedure of Manufacturing Example 1 was repeated except that methyl polyoxyethylene methacrylate (oxyethylene 23 mol adduct) was used instead of A-1 as the component (A). A polymer was produced. Mw of the obtained copolymer was measured in the same manner as in Production Example 1.
Was measured. The results are shown in Table 2 together with the neutralization rate.

Production Example 8 A copolymer was prepared in the same manner as in Production Example 1 except that 515 g of A-1 was used as the monomer component and no NaOH aqueous solution was added after the reaction. Manufactured. The Mw of the obtained copolymer was measured by the same method as in Production Example 1. The results are shown in Table 3.

[0074]

[Table 3]

[Production Example 9] In Production Example 1, the monomer components were replaced by 65 g of A-1 and 450 g of styrene,
Replace the solvent with methyl ethyl ketone and use 25% polymerization initiator
Change to 100 g of azobisisobutyronitrile solution, and use 36 g of 25% N-dodecyl mercaptan solution as chain transfer agent.
And a copolymer was produced in the same manner as in Production Example 1 except that the neutralizing aqueous NaOH solution was not added. The Mw of the obtained copolymer was measured by the same method as in Production Example 1. The results are shown in Table 3.

Production Example 10 A copolymer was produced in the same manner as in Production Example 9, except that the monomer components in Production Example 9 were changed to 65 g of A-1, 100 g of methacrylic acid and 350 g of styrene. did. After the polymerization, the pH was adjusted to 8.8 by neutralizing with 110 g of dimethylethanolamine. The Mw of the obtained copolymer was measured by the same method as in Production Example 1. The results are shown in Table 3 together with the neutralization rate.

Production Example 11 In Production Example 10, the monomer components were 415 g of styrene and 100 of methacrylic acid.
A copolymer was produced in the same manner as in Production Example 9 except that the amount was changed to g. After polymerization, dimethyl ethanolamine 110g
Was neutralized with and the pH was adjusted to 8.8. The Mw of the obtained copolymer was measured by the same method as in Production Example 1. The results are shown in Table 3 together with the neutralization rate.

Examples 1 to 4 and Comparative Examples 1 and 2 (dispersing agent for calcium carbonate) (wet grinding test of heavy calcium carbonate) 25 parts of water and Table 4
0.5 part of the copolymer shown in (1) was stirred and mixed to uniformly dissolve the copolymer to prepare an aqueous dispersant solution. 75 parts of coarsely ground ore of calcium bicarbonate was added to the aqueous dispersant solution, and the mixture was stirred and dispersed for 40 minutes using a sand grinder. Immediately after the production of the obtained 75 mass% calcium carbonate aqueous slurry, and at 25 ° C.
The viscosity after standing for 7 days at 25 ° C. using a BL viscometer is 6
The measurement was performed under the condition of 0 rpm. The results are shown in Table 4.

[0079]

[Table 4]

Examples 5 to 10, Comparative Examples 3 and 4
(Dispersant for Calcium Carbonate) (Dispersion Test of Light Calcium Carbonate) 25 parts of water and 0.4 part (solid content) of the copolymer shown in Table 5 are stirred and mixed to be uniformly dissolved to produce an aqueous dispersant solution. did. 75 parts of light calcium carbonate powder was added to the aqueous dispersant solution, and the mixture was stirred and dispersed at 4,000 rpm for 15 minutes using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). The viscosity immediately after dispersion and after standing at 25 ° C. for 7 days was measured at 25 ° C. and 60 rp using a BL viscometer.
It was measured under the condition of m. The results obtained are shown in Table 5.

[0081]

[Table 5]

Examples 11 to 16 and Comparative Examples 5 and 6
(Dispersant for ceramics) Mud cake for ceramics containing 60% of water (Al ₂
To 123 g of O ₃ (52%, SiO ₂ ; 36%), 1.22 g (solid content) of dispersant and 155 g of water were added, and the mixture was uniformly dispersed with a commercially available juicer. After the dispersion, the viscosity of the slurry was measured by a BL type viscometer at 25 ° C. and 60 rpm. The obtained results are shown in Table 6.

[0083]

[Table 6]

Examples 17 to 21 and Comparative Examples 7 to 9
(Dispersant for drilling mud) Specific gravity of alluvial cohesive soil collected in Osaka city is 1.1
6, viscosity of 940 cps, muddy water 200 adjusted to pH 6.98
A dispersant having a predetermined concentration relative to g was added to the juicer mixer and stirred for 5 minutes. Using a B-type viscometer, 25 ° C, 6
The viscosity of the muddy water was measured under the condition of 0 rpm. Table 7 shows the concentration of the added dispersant and the test results.

[0085]

[Table 7]

Examples 22 to 27, Comparative Examples 10 and 11 (dispersing agent for drilling mud) 400 g of water and 6.86 g of dispersing agent in a juicer mixer
(Solid content), bentonite [Kunimine Industries Co., Ltd. Kunigel VI] 28g were added, and Portland cement 29.0g was further added and stirred for 5 minutes. The funnel viscosity was measured using a 500 ml funnel viscometer immediately after dispersion and 3 days and 7 days later. Table 8 shows the concentration of the added dispersant and the test results.

[0087]

[Table 8]

Examples 28 to 30, Comparative Example 12 (dispersing agent for aqueous ink) 5.0 parts of the aqueous solution of the copolymer produced in Production Examples 8 to 11,
Ion-exchanged water 74.0 parts, diethylene glycol 5.0
Part, carbon black [Mitsubishi Chemical Co., Ltd. MCF88]
After mixing 15.0 parts and 1.0 part of isopropyl alcohol and premixing for 30 minutes, dispersion treatment was performed under the following conditions. Dispersing machine: Sand grinder (made by Igarashi Kikai) Grinding media: Zirconium beads (1 mm diameter) Filling ratio of grinding media: 50% (volume) Grinding time: 3 hours Centrifugal separation (12000 RPM,
20 minutes) to remove coarse particles, and to 30 parts of the resulting dispersion, 2 parts of glycerin and 15 parts of diethylene glycol are added.
Parts, 5 parts of N-methylpyrrolidone, 3 parts of isopropyl alcohol and 45 parts of ion-exchanged water were mixed and adjusted to pH 8-10 with monoethanolamine to prepare an aqueous ink. The obtained water-based ink was evaluated for the items (a) to (h) below. The results are shown in Table 9.

(A) Print density Micro bubble jet printer [manufactured by Canon Inc.]
Solid printing was performed on recycled paper for PPC (manufactured by Nippon Paper Industries Co., Ltd.) using the model number BJ-10VL]. And at room temperature 24
The optical density of the print after naturally drying for a period of time was measured with a Macbeth densitometer RD918 (manufactured by Macbeth).

(B) Print misalignment, (c) Ink non-ejection After continuous printing (2000 sheets) by the above printer,
It was confirmed whether the print was twisted or ink was not ejected.

(D) Liquid Reservoir After continuously printing 10 sheets using the above printer, the face surface of the recording head was observed with a microscope. Those with liquid pools on the face surface were evaluated as bad (×), and those without liquid pools were evaluated as good (◯).

(E) Light resistance The printed matter printed by the above printer was irradiated with light for 200 hours using a fade meter (manufactured by Atlas). The print density before and after the light irradiation was measured, and the light resistance was calculated from the following formula. Light resistance (%) = (print density after light irradiation / print density before light irradiation) × 100

(F) Water resistance The printed matter printed by the above printer was immersed in tap water for 5 minutes. The print density before and after the immersion was measured, and the water resistance was calculated from the following formula. Water resistance (%) = (print density after immersion in water / print density before immersion in water) × 100

(G) Scratchability The printed matter printed by the above printer and 5 minutes after printing was rubbed with a finger. When the ink did not adhere to the finger, it was evaluated as good (◯), and when it adhered, it was evaluated as bad (x).

(H) Storage stability The water-based ink is kept in a sealed glass container for 60 months for 60 months.
Stored at ° C. The degree of aggregation and thickening of the pigment in the water-based ink after storage was observed, and those in which aggregation and thickening occurred were rated as bad (x), and those that did not occurred were rated as good (◯).

[0096]

[Table 9]

[0097]

The dispersant of the present invention is unlikely to cause hydrolysis even in an alkaline atmosphere, such as when calcium carbonate is dispersed, so that the viscosity of the obtained slurry is unlikely to change and the slurry viscosity is stable over time. Excellent in performance. or,
Even when used in ceramics particles or mud such as drilling mud, the viscosity becomes lower than that of conventional dispersants, and dispersion stability hardly changes even when cement or other alkalis or salts are mixed, so high concentrations for ceramic materials It excels in slurrying ability and mud wall forming ability of excavated holes in coastal areas and high-rise building sites. When the dispersant of the present invention is used as a dispersant for water-based inks, it is excellent in various dispersion performances, particularly in dispersion stability, and the ink obtained is excellent in various ink performances. Further, the dispersant of the present invention can be added in a small amount,
Superior performance compared to conventional ones can be obtained.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ identification code FI theme code (reference) C09K 7/00 C09K 7/00 F 7/02 7/02 C (72) Inventor Yoshio Mori Nagoya City, Aichi Prefecture F-term in the Polymer Materials Research Laboratory, Toagosei Co., Ltd., 1 Funa-cho, Minato-ku (reference) 4D077 AB02 AB04 AB10 AB17 AC05 BA02 BA07 DD13Y DD29Y DE04Y DE07Y DE09Y DE24Y 4J027 AC02 AC03 AC04 AC07 AC08 AC09 BA01 BA03 BA06 BA08 BA14 CA11 CB04 CB09 CD08 4J039 AD20 AD21 AE07 BE01 BE02 BE12 BE16 BE22 CA03

Claims (10)

[Claims] 1. A macromonomer (A) having an ethylenically unsaturated group represented by the following general formula (1) and optionally a compound (B) other than the component (A) having an ethylenically unsaturated group. A dispersant containing a polymer as a constituent monomer unit. Embedded image A-P1-X- (R ¹ O) _n R ² ... (1) [In the general formula (1), A is an ethylenically unsaturated group, and Pl is a substituent. a phenylene group which may have a, X is -R ³ O- (R ³ represents an alkylene group having 1 to 7 carbon atoms), - O -, - NHCOO -, - R 4 NHCOO-
(R ⁴ is an alkylene group having 1 to 7 carbon atoms) or -CONH
And R ¹ is an alkylene group having 2 to 4 carbon atoms, and R ² is a hydrogen atom, an alkyl group or an aromatic group. n is 1 to 30
It is an integer of 0. ] 2. The polymer according to claim 1, wherein the polymer is a polymer having a compound having an ethylenically unsaturated group and a hydrophilic group as a component (B) as a constituent monomer unit and / or a salt thereof. Dispersant. 3. The dispersant according to claim 2, wherein the component (B) is a compound having ethylenic unsaturation and a carboxyl group. 4. The polymer comprises 3 to 3 of all carboxyl groups.
The dispersant according to claim 3, wherein 100 mol% is a neutralized salt. 5. The polymer has a weight average molecular weight of 1,000.
The dispersant according to any one of claims 1 to 4, which has a content of -100,000. 6. A dispersant for calcium carbonate comprising the dispersant according to claim 1. 7. A mud dispersant comprising the dispersant according to any one of claims 1 to 5. 8. The dispersant according to claim 1, wherein the polymer is a polymer having, as the component (B), a compound having an ethylenically unsaturated group and a hydrophobic group as a constituent monomer unit. 9. The polymer has a weight average molecular weight of 1,000.
9. The dispersant of claim 8 having a viscosity of -100,000. 10. A dispersant for water-based ink, which comprises the dispersant according to any one of claims 1, 8 and 9.