JP6476381B2 - Water-based pigment dispersion and method for producing the same - Google Patents

Description

  The present invention relates to a water-based pigment dispersion that can be used for, for example, a water-based paint for coating steel sheets, an ink jet recording ink, and the like, and a method for producing the same.

  Water-based pigment dispersions in which pigments are dispersed in water are widely used as inkjet recording inks for general consumers from the viewpoint of safety and ease of handling. In addition, the coating of the steel plate constituting the body of an automobile or the like was performed by applying a solvent-based paint to the surface of the underlayer formed on the steel plate and baking the obtained coating film in a high-temperature furnace. Organic solvents contained in paints cause environmental pollution, and are VOCs (volatile organic compounds) that may adversely affect the health of workers. From the viewpoints of environmental protection and work environment safety, etc. The replacement of solvent-based paints with water-based paints, that is, water-based pigment dispersions, is proceeding.

  One of the problems in forming a painted surface on a steel sheet using an aqueous pigment dispersion is that the saturation of the aqueous pigment dispersion itself cannot be sufficiently reproduced on the painted surface. That is, the saturation of a coating film made of an aqueous pigment dispersion, and the saturation of a coating film (painted surface) made of a paint prepared for steel sheet coating by blending a resin component and other auxiliary components into the aqueous pigment dispersion. There is a relatively large difference between the two, and the latter is inferior to the former. Since saturation is a very important indicator of color vividness, for example, a car constructed from a painted surface with low saturation has a poor impression and greatly reduces consumers' willingness to purchase.

  On the other hand, it is well known to make pigment particles finer by salt milling or the like. However, the pigment has a characteristic that it tends to re-agglomerate and coarsen in water, and the saturation of the aqueous pigment dispersion may decrease. In addition, the reaggregation of the pigment not only reduces the saturation of the aqueous pigment dispersion, but also increases the viscosity. In this case, clogging at the ink discharge port of the ink jet printer or bleeding of the printing surface may occur. It becomes the cause of etc. In order to suppress such reaggregation of the pigment, a polymer dispersant is conventionally blended in the aqueous pigment dispersion. The polymer dispersant is considered to suppress reaggregation of the pigment by adhering to at least a part of the pigment particle surface.

Conventionally, various types of polymer dispersants have been proposed. For example, Patent Document 1 includes a hydrophobic monomer and a hydrophilic monomer having an acrylamide structure represented by the following formula (1), and may further include an anionic hydrophilic monomer, and a part of the hydrophobic monomer is blocked. Disclosed is a polymeric dispersant that forms the part.
Formula (1): R ¹ —C (═CH ₂ ) —C (═O) NH (CH ₂ CH ₂ O) _n X
[Wherein, R ¹ represents a hydrogen atom or a methyl group. X represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. n is 1-10. ]

  Patent Document 2 discloses alkyl (meth) acrylates having 1 to 18 carbon atoms in the alkyl portion, benzyl (meth) acrylate, phenyl (meth) acrylate, (meth) acrylonitrile, glycidyl (meth) acrylate, p-tolyl (meth). ) Hydrophobic blocks composed of hydrophobic monomers such as acrylates, styrene compounds, N-alkyl (meth) acrylamides, vinyl acetate, vinyl butyrate, vinyl benzoate, (meth) acrylic acid, maleic acid, itaconic acid, Hydrophilic blocks composed of hydrophilic monomers such as crotonic acid, N, N-dialkylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate, vinylpyridine, etc., wherein the alkyl moiety has 1 to 2 carbon atoms And a block copolymer comprising:

  As disclosed in Patent Documents 1 and 2, it is known to blend a polymer or block copolymer containing a hydrophilic portion and a hydrophobic portion into a water-based pigment dispersion as a polymer dispersant. However, the polymer dispersants disclosed in Patent Documents 1 and 2 are used to improve fastness such as ink fixability and scratch resistance, and improve the saturation of the coating film formed from the ink. It doesn't let you.

  Patent Document 3 discloses a block (a) made of a homopolymer of butyl acrylate (BA), a block (b) made of a homopolymer of methoxypolyethylene glycol monoacrylate (MPEGA), and 4-vinylpyridine (4 -VP) is a homopolymer of block (c), and a block copolymer comprising a polymer dispersant is disclosed as a polymer dispersant (paragraph [0248] to [0262] and paragraph [ 0288] to [0297]).

  However, in the block copolymer disclosed in Patent Document 3, the blocks (a) and (b) do not contain a structural unit derived from an anionic water-soluble compound, and the blocks (a) and (b) Is also a homopolymer. It is clear from Patent Document 3 that due to the difference in the polymer structure, the saturation of the water-based pigment dispersion can be improved and the saturation can be maintained when the dispersion is used as a coating material such as a steel plate. is not.

JP 2010-013585 A Japanese Patent Laid-Open No. 2015-024508 Special table 2008-527130 gazette

  An object of the present invention is to form a paint film having a saturation equal to or higher than that of the above-mentioned paint film even when it is used as a paint for painting such as a steel sheet, which can form a paint film with high chroma. It is to provide an aqueous pigment dispersion that can be used and a method for producing the same.

  As a result of intensive studies to solve the above problems, the present inventors have found that the polymer block (A) containing a structural unit derived from a cyclic amine compound, a structural unit derived from a nonionic water-soluble compound, and an anionic water solution Surface treatment of a fine pigment with a surface treatment agent containing a block copolymer (I) and a polymer block (B) containing a structural unit derived from a functional compound and not containing a structural unit derived from the cyclic amine compound As a result, it was found that an aqueous pigment dispersion meeting the purpose was obtained, and the present invention was completed.

  That is, this invention provides the manufacturing method of the aqueous pigment dispersion of the following (1)-(13) and the aqueous pigment dispersion of (14)-(18).

(1) A polymer block (A) containing a structural unit derived from a cyclic amine compound, a structural unit derived from a nonionic water-soluble compound and a structural unit derived from an anionic water-soluble compound, and a structural unit derived from a cyclic amine compound A water-based pigment dispersion comprising a polymer block (B) that does not contain and a micronized pigment that has been surface-treated with a surface treatment agent comprising the block copolymer (I).
(2) The aqueous pigment dispersion according to (1), wherein the polymer block (B) further contains a structural unit derived from a nonionic water-insoluble compound.
(3) The aqueous pigment dispersion according to (1) or (2), wherein the polymer block (B) is a random copolymer.
(4) The aqueous pigment dispersion according to any one of (1) to (3) above, wherein the cyclic amine compound is a 5-membered or 6-membered nitrogen-containing heterocyclic compound having a group containing a polymerizable double bond.
(5) The nitrogen-containing heterocyclic compound is 2-vinylpyridine, 4-vinylpyridine, 1-vinylimidazole, 1-vinyl-1H-pyrazole, 1-vinyl-2-imidazoline, 2-vinyl-2-imidazoline, 2 -The aqueous pigment dispersion of (4), which is at least one selected from the group consisting of vinylpyrazine and 2-vinyl-4,6-diamino-1,3,5-triazine.
(6) The above (1) to (5), wherein the nonionic water-soluble compound is a polymerizable nonionic water-soluble organic compound having at least one hydrophilic group selected from the group consisting of a hydroxyl group and an amide group. ) Any one of the aqueous pigment dispersions.
(7) The nonionic water-soluble organic compound is selected from the group consisting of polyalkylene glycol, polyalkylene glycol (meth) acrylate, hydroxyalkyl (meth) acrylate, (meth) acrylamide compound, N-vinylpyrrolidone, and alkylene oxide. The aqueous pigment dispersion of (6), which is at least one kind.
(8) The anionic water-soluble compound is an organic acid compound having at least one acid group selected from the group consisting of a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group, and a group containing a polymerizable double bond. The water-based pigment dispersion according to any one of (1) to (7) above.
(9) A group in which the nonionic water-insoluble compound contains at least one hydrophobic group selected from the group consisting of a chain hydrocarbon group, a cyclic hydrocarbon group, and an aromatic hydrocarbon group, and a polymerizable double bond The water-based pigment dispersion according to any one of (2) to (8), which is a nonionic water-insoluble organic compound having
(10) The nonionic water-insoluble organic compound is at least one selected from the group consisting of chain alkyl (meth) acrylates, cycloalkyl (meth) acrylates, aryl (meth) acrylates, and styrenic compounds ( 9) Aqueous pigment dispersion.
(11) The block copolymer (I) is a structural unit derived from a cyclic amine compound, 5 to 30% by weight, a nonionic water-soluble compound, derived from 40 to 80% by weight, and an anionic water-soluble compound. The aqueous pigment dispersion of (1) above, containing 0.5 to 20% by weight.
(12) The block copolymer (I) is a structural unit derived from a cyclic amine compound of 5 to 30% by weight, a nonionic water-soluble compound derived from 40 to 80% by weight, and an anionic water soluble compound derived structural unit 0 The aqueous pigment dispersion of (2) above, containing 5 to 20% by weight and 10 to 50% by weight of a structural unit derived from a nonionic water-insoluble compound.
(13) The aqueous pigment dispersion according to any one of the above (1) to (12), wherein the block copolymer (I) has an acid value of 20 mgKOH / g or more and an amine value of 40 mgKOH / g or more.

(14) A method for producing an aqueous pigment dispersion according to any one of (1) to (13) above, wherein the pigment, the water-soluble inorganic salt, and the water-soluble solvent are kneaded to grind the pigment, and the fine pigment And a surface treatment step of adding the above-mentioned surface treatment agent to the first mixture to obtain a second mixture containing the finely-pigmented pigment surface-treated with the surface treatment agent. A method for producing a water-based pigment dispersion.
(15) A method for producing an aqueous pigment dispersion according to any one of (1) to (13), wherein the surface treatment agent, pigment, water-soluble inorganic salt, and water-soluble solvent are kneaded and the pigment is ground. And a micronized surface treatment step of obtaining a second mixture containing the micronized pigment surface-treated with the surface treating agent.
(16) The method for producing an aqueous pigment dispersion according to the above (14) or (15), comprising a solvent treatment step of adding and mixing a solvent incompatible with the water-soluble solvent into the second mixture.
(17) The solvent incompatible with the water-soluble solvent is at least selected from the group consisting of alcohol solvents, ketone solvents, ester solvents, ether solvents, aliphatic hydrocarbon solvents, and aromatic hydrocarbon solvents. The method for producing a water-based pigment dispersion according to (16), which is a kind.
(18) The second mixture obtained in the surface treatment step or the miniaturized surface treatment step, or the second mixture containing a solvent incompatible with the water-soluble solvent obtained in the solvent treatment step is washed with water. The method for producing an aqueous pigment dispersion according to any one of (14) to (17), wherein the inorganic salt, the water-soluble solvent, and the solvent that is incompatible with the water-soluble solvent are removed from the second mixture.

  The water-based pigment dispersion of the present invention can form a coating film having high saturation, and even when it is used as a coating material for coating a steel sheet, etc., it has a coating surface having the same or higher saturation as the coating film. A coating film can be formed.

  The aqueous pigment dispersion of the present invention comprises a polymer block (A) containing a structural unit derived from a cyclic amine compound, a structural unit derived from a nonionic water-soluble compound and a structural unit derived from an anionic water-soluble compound, and cyclic. The polymer block (B) which does not contain the structural unit derived from an amine compound, and the refinement | purification pigment surface-treated with the surface treating agent containing the block copolymer (I) are characterized by the above-mentioned. That is, the water-based pigment dispersion of the present invention includes a finer pigment treated with a surface treating agent containing the specific block copolymer (I), an optional component, and water.

The surface treatment in the present invention includes a state in which the surface treatment agent is attached to at least a part of the surface of the fine pigment particles. In addition, it is not necessary that all the surface treatment agents adhere to the surface of the fine pigment particles, and a part of the surface treatment agent may be dissolved or dispersed in the aqueous pigment dispersion. Further, it is not necessary that the surface treatment agent is attached to the surface of all the fine pigment particles.
Hereinafter, each component contained in the water-based pigment dispersion of the present invention will be described in further detail.

[Fine refined pigment]
In the present invention, a refined pigment obtained by refining a pigment by a pigment refining method such as a salt milling method is used. The primary particle size of the fine pigment is not particularly limited, but is preferably 100 nm or less, more preferably 80 nm or less. In the present specification, the primary particle size of the micronized pigment is, for example, from an image of 50,000 times and 100,000 times by a transmission electron microscope (trade name: JEM-1011, manufactured by JEOL Ltd.), an arbitrary fine size. 50 fine pigment particles are selected, and the maximum particle diameter of each fine pigment particle is measured based on the measuring scale shown in the image, and is obtained as an arithmetic average.

  The pigment to be refined is not particularly limited, and for example, at least one organic pigment selected from azo pigments, phthalocyanine pigments, and condensed polycyclic pigments can be used. Condensed polycyclic pigments include anthraquinone pigments, quinacridone pigments, indigo pigments, dioxazine pigments, perylene pigments, perinone pigments, isoindolinone pigments, isoindoline pigments, metal complex pigments, quinophthalone. And pigments such as diketopyrrolopyrrole pigments. The condensed polycyclic pigments can be used alone or in combination of two or more.

  The refinement of the pigment by the salt milling method is performed, for example, by mixing a pigment, a water-soluble inorganic salt (also referred to as an inorganic milling agent), and a water-soluble solvent, and using a kneader or the like to mix the obtained salt milling mixture. Kneading is carried out and the pigment is ground mainly with a water-soluble inorganic salt.

  The water-soluble inorganic salt is present in the form of crystals in the salt milling mixture and is ground in contact with the pigment by a kneading operation. As the water-soluble inorganic salt, any water-soluble inorganic salt conventionally used in the salt milling method can be used, and examples thereof include sodium chloride (sodium chloride), mirabilite (sodium sulfate) and its anhydride, and potassium chloride. . The amount of the water-soluble inorganic salt used is preferably 100 parts by weight to 3000 parts by weight with respect to 100 parts by weight of the pigment. When the amount of the water-soluble inorganic salt is within the above range, the pigment can be sufficiently miniaturized while suppressing an increase in cost required for miniaturization.

  The water-soluble solvent is not particularly limited as long as it wets the pigment and the water-soluble inorganic salt, dissolves (mixes) in water, and does not substantially dissolve the water-soluble inorganic salt. However, since the temperature rises during salt milling and the solvent easily evaporates, it is preferable to use a high boiling point solvent having a boiling point of 120 ° C. or higher from the viewpoint of safety. Further, as the water-soluble solvent, it is necessary to use a hydrophilic solvent. Specifically, for example, a liquid having a solubility in 100 g of water at 25 ° C. of water of 3 g or more can be used.

  Examples of the water-soluble solvent include 2-methoxyethanol, 2-butoxyethanol, 2- (isopentyloxy) ethanol, 2- (hexyloxy) ethanol, ethylene glycol, diethylene glycol, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate. , Diethylene glycol monobutyl ether, triethylene glycol, triethylene glycol monomethyl ether, liquid polyethylene glycol, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, dipropylene glycol, dipropylene glycol monomethyl ether, dipropylene glycol mono Examples include ethyl ether and liquid polypropylene glycol. A water-soluble solvent can be used alone or in combination of two or more. The total amount of the water-soluble solvent may be added at the initial stage of salt milling, or may be added in appropriate portions during salt milling.

  Although the usage-amount of a water-soluble solvent is not specifically limited, Preferably it is 5 to 50 weight% of the total amount of a water-soluble inorganic salt and a water-soluble solvent, More preferably, it is 10 to 40 weight%, More preferably, it is 15 to 35 weight% %. When the amount of the water-soluble solvent is within the above range, uniform kneading can be performed, and further, shearing force is easily applied to the kneaded product, so that there is little variation in particle size and sufficient refinement is achieved. Can be obtained.

[Surface treatment agent]
In the present invention, as described above, the polymer block (A) containing a structural unit derived from a cyclic amine compound (hereinafter sometimes referred to as “cyclic amine unit”) and a structural unit derived from a nonionic water-soluble compound ( Includes a structural unit derived from an anionic water-soluble compound (hereinafter may be referred to as an “anionic water-soluble unit”), and includes a cyclic amine unit. A surface treating agent containing a block copolymer (I) containing no polymer block (B) as an active ingredient is used. As the form of the surface treatment agent, a form consisting only of the block copolymer (I), a solution form in which the block copolymer (I) is dissolved in water and / or a solvent, and a block copolymer (I) containing water and Examples thereof include a dispersion form dispersed in a solvent.

  By using the surface treating agent containing the block copolymer (I), for example, the saturation of the coating film made of the aqueous pigment dispersion is increased, and the saturation of the coating film formed on the surface is increased by the aqueous pigment dispersion. It is possible to form a coated surface coating film having a saturation equivalent to or higher than that of a coating film made of a water-based pigment dispersion, even for a base material known to be lower than that of a coating film made of. At present, the reason why such an effect is obtained is not sufficiently clear. However, in the block copolymer (I), the polymer block (A) selectively adheres to the surface of the finely divided pigment particles, and the polymer block It is thought that this is because the polymer block (B) having a relatively higher hydrophilicity than (A) is easily disposed on the water or aqueous medium side.

  The block copolymer (I) is composed of an AB type diblock copolymer, an ABA type or BAB type triblock copolymer, and an ABAB type tetrablock copolymer. Any of block copolymer, ABABABA type or BBABABA type pentablock copolymer, and more multiblock copolymer may be used. From the viewpoint of dispersibility of the fine pigment, the block copolymer (I) in which the polymer block (A) is arranged at one end and the polymer block (B) is arranged at the other end is preferable.

  The polymer block (A) is a block made of a homopolymer of a cyclic amine compound or a copolymer of a cyclic amine compound and a compound copolymerizable therewith. The copolymer may be a random copolymer or a block copolymer. The cyclic amine unit contained in the homopolymer and copolymer may be quaternized as necessary. As the cyclic amine compound, a nitrogen heterocyclic compound having a group containing a polymerizable double bond (hereinafter sometimes referred to as “polymerizable group”) can be used without particular limitation, and among them, 5 having a polymerizable group. More preferred are 6-membered or 6-membered nitrogen-containing heterocyclic compounds. The polymerizable group is preferably an alkenyl group, more preferably a vinyl group.

  Specific examples of the 5- or 6-membered nitrogen-containing heterocyclic compound having a polymerizable group include, for example, 2-vinylpyridine, 4-vinylpyridine, 1-vinylimidazole, 1-vinyl-1H-pyrazole, 1-vinyl. Examples include 2-imidazoline, 2-vinyl-2-imidazoline, 2-vinylpyrazine, 2-vinyl-4,6-diamino-1,3,5-triazine. Among these, 2-vinyl pyridine, 4-vinyl pyridine, and the like are preferable from the viewpoint of improving dispersibility of the finer pigment by the surface treatment agent and further improving the chroma. A cyclic amine compound can be used individually by 1 type or in combination of 2 or more types.

  The content of the cyclic amine unit in the block copolymer (I) is not particularly limited, but is preferably 5 to 30% by weight, more preferably 5 to 25% by weight, based on the total amount of the block copolymer (I). More preferably, it is 7 to 20% by weight. If the content of the cyclic amine unit is within the above range, the amount of adhesion of the block copolymer (I) to the surface of the finely divided pigment particles becomes an appropriate amount, and the effect of increasing the saturation is sufficiently exerted. Both the saturation of the coating film made of the aqueous pigment dispersion and the coating film made of the paint prepared from the dispersion can be brought to a high level.

  Moreover, the compound copolymerizable with a cyclic amine compound can be copolymerized with a cyclic amine compound in the range which does not impair the effect by block copolymer (I). Examples of the copolymerizable compound include nonionic water-insoluble compounds described later, and among them, butyl acrylate, methyl methacrylate, styrene and the like are preferable. These copolymerizable compounds can be used singly or in combination of two or more.

  On the other hand, the polymer block (B) includes a nonionic water-soluble unit and an anionic water-soluble unit, and preferably a structural unit derived from a nonionic water-soluble unit, an anionic water-soluble unit, and a nonionic water-insoluble compound ( Hereinafter referred to as “nonionic water-insoluble unit”) and a block made of a copolymer containing no cyclic amine unit. The polymer block (B) may be a random copolymer or a block copolymer, but the viewpoint of improving the chroma of a coating film formed from a water-based pigment dispersion and a paint for each application prepared using the same. Therefore, a random copolymer is preferable.

  The nonionic water-soluble unit is a divalent structural unit derived from a nonionic water-soluble compound. The nonionic water-soluble compound is not particularly limited as long as it is a nonionic and water-soluble and polymerizable organic compound, but at least one hydrophilic group selected from the group consisting of a hydroxyl group and an amide group (hereinafter referred to as “nonionic water-soluble compound”). A nonionic water-soluble organic compound having a polymerizable group that may be simply referred to as “hydrophilic group” is preferable. The nonionic water-soluble organic compound may have a polymerizable group, and the polymerizable group is preferably an alkenyl group, more preferably a vinyl group.

  Nonionic water-soluble organic compounds that have a hydrophilic group and can be polymerized include, for example, polyalkylene glycol, polyalkylene glycol (meth) acrylate, hydroxyalkyl (meth) acrylate, (meth) acrylamide compound, and N-vinylpyrrolidone. And alkylene oxides. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the polyalkylene glycol include polyalkylene glycols having 2 to 4 carbon atoms in the alkylene chain, such as polyethylene glycol, polypropylene glycol, and polybutylene glycol.

  Examples of the polyalkylene glycol (meth) acrylate include monofunctional or polyfunctional esters of a polyalkylene glycol having an alkylene chain with 2 to 4 carbon atoms and acrylic acid or methacrylic acid, more specifically. Polyethylene glycol monomethacrylate, methoxypolyethylene glycol monomethacrylate, polyethylene glycol dimethacrylate, phenoxypolyethylene glycol acrylate, polypropylene glycol monomethacrylate, polypropylene glycol diacrylate, and the like.

  Examples of the hydroxyalkyl (meth) acrylate include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, etc. The hydroxyalkyl (meth) acrylate which is is mentioned.

  Examples of the (meth) acrylamide compound include (meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-propyl (meth) acrylamide, N-isopropyl (meth) acrylamide, and N-n. -Butyl acryl (meth) amide, Nt-butyl (meth) acrylamide, N-cyclohexyl (meth) acrylamide, N- (2-methoxyethyl) (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N , N-diethyl (meth) acrylamide, N-phenyl (meth) acrylamide, N-benzyl (meth) acrylamide, diacetone acrylamide and the like.

  Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, and the like.

  The content of the nonionic water-soluble unit in the block copolymer (I) is preferably 40 to 80% by weight, more preferably 45 to 75% by weight, and still more preferably based on the total amount of the block copolymer (I). Is 45 to 73% by weight. When the content of the nonionic water-soluble unit is within the above range, the saturation of the coating film made of the aqueous pigment dispersion can be increased, and the viscosity increase or gelation of the aqueous pigment dispersion can be suppressed.

  An anionic water-soluble unit is a divalent structural unit derived from an anionic water-soluble compound. The anionic water-soluble compound is not particularly limited as long as it is an anionic and water-soluble organic compound having a polymerizable group, but at least selected from the group consisting of a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group. An anionic water-soluble organic acid compound having one acid group (hereinafter sometimes simply referred to as “acid group”) and a polymerizable group in one molecule is preferable. The polymerizable group is preferably an alkenyl group, and more preferably a vinyl group.

  Specific examples of the anionic water-soluble organic acid compound having an acid group and a polymerizable group include a carboxylic acid compound, a sulfonic acid compound, and a phosphoric acid compound. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the carboxylic acid compound include acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, fumaric acid, maleic acid, cinnamic acid, 2-methylmaleic acid, itaconic acid, 2-methylitaconic acid, sorbic acid, α, β -Methyl glutaric acid, maleic anhydride, itaconic anhydride, acrylic anhydride, methacrylic anhydride, and salts thereof.

  Examples of the sulfonic acid compound include vinyl sulfonic acid, styrene sulfonic acid, isoprene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, allyl sulfonic acid, methallyl sulfonic acid, allyloxybenzene sulfonic acid, and methallyl sulfonic acid. , (Meth) allyloxybenzenesulfonic acid, 2-allyloxy-2-hydroxypropanesulfonic acid, 3-allyloxy-2-hydroxy-1-propanesulfonic acid, 2-methacryloyloxyethanesulfonic acid, and salts thereof It is done.

  Examples of the phosphoric acid compound include 2-methacryloyloxyethyl phosphoric acid, 2-methacryloyloxyethylphenyl phosphoric acid, 10-methacryloyloxydecamethylene phosphoric acid, 4-vinylbenzyl phosphoric acid, pentaacryloyldipentaerythritol phosphoric acid, and These salts and phosphate esters such as 2- (meth) acryloyloxyethyl phosphate, diethyl (vinylphenyl) phosphate, 4-vinylbenzenephosphinic acid diethyl ester, diphenyl-2-methacryloyloxyethyl phosphate, and the like can be mentioned.

  In addition, since a phosphoric acid group can also be a polymerizable group [= P (O) (OH)], phosphoric acid, trimethyl phosphate, triethyl phosphate, tributyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, Phosphate esters such as tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate may also be used as the anionic water-soluble organic acid compound.

  The content of the anionic water-soluble unit in the block copolymer (I) is preferably 0.5 to 20% by weight, more preferably 0.5 to 15% by weight with respect to the total amount of the block copolymer (I). %, More preferably 1 to 10% by weight. When the content of the anionic water-soluble unit is within the above range, the gelation of the aqueous pigment dispersion, the decrease in the dispersibility of the fine pigment in the dispersion, and the like are suppressed, and the color of the coating film comprising the dispersion is reduced. The degree can be increased sufficiently.

  The nonionic water-insoluble unit is a divalent structural unit derived from a nonionic water-insoluble compound. Nonionic water-insoluble units are used, for example, to adjust the degree of hydrophilicity of the polymer block (B). Moreover, when the hydrophilic property of a nonionic water-insoluble unit is higher, there exists a function which improves the hydrophilic property of a polymer block (B). The nonionic water-insoluble compound is not particularly limited as long as it is a nonionic and water-insoluble organic compound having a polymerizable group, but a chain hydrocarbon group, a cyclic hydrocarbon group, an aromatic hydrocarbon group. Nonionic water-insoluble organic compounds having at least one hydrophobic group selected from the group consisting of these groups (hereinafter sometimes simply referred to as “hydrophobic group”) and a polymerizable group in one molecule are preferred. The polymerizable group is preferably an alkenyl group, and more preferably a vinyl group.

  Nonionic water-insoluble organic compounds having a hydrophobic group and a polymerizable group in one molecule include, for example, chain alkyl (meth) acrylates, cycloalkyl (meth) acrylates, aryl (meth) acrylates, styrene compounds, etc. Is mentioned. These can be used individually by 1 type or in combination of 2 or more types.

  Examples of the chain alkyl (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and isobutyl (meth). Examples include alkyl (meth) acrylates having 1 to 17 carbon atoms in the alkyl moiety, such as acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and glycidyl (meth) acrylate. It is done.

Examples of the cycloalkyl (meth) acrylate include cyclopropyl (meth) acrylate, cyclobutyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, cyclooctyl (meth) acrylate, Examples thereof include cycloalkyl (meth) acrylates having 3 to 10 carbon atoms in the cycloalkyl moiety, such as cyclononyl (meth) acrylate and cyclodecyl (meth) acrylate.
Examples of the aryl (meth) acrylate include benzyl (meth) acrylate and phenoxyethyl (meth) acrylate.

  Examples of the styrene compound include styrene, α-methylstyrene, methylstyrene, 3-methylstyrene, 4-methylstyrene, 3-ethylstyrene, 4-ethylstyrene, 4-aminostyrene, 4-dimethylaminostyrene, and methoxystyrene. , Chloromethylstyrene, chlorostyrene, 4-tert-butylstyrene, vinyltoluene, vinyltoluene, and the like, a chain alkyl group having 1 to 4 carbon atoms, a chain alkoxy group having 1 to 4 carbon atoms, a halogen atom, and amino Examples thereof include styrene compounds having at least one selected from the group consisting of groups as a substituent.

  The content of the nonionic water-insoluble unit in the block copolymer (I) is preferably 10 to 50% by weight, more preferably 15 to 45% by weight, further based on the total amount of the block copolymer (I). Preferably it is 20 to 40 weight%. If the content of the nonionic water-insoluble unit is within the above range, a decrease in the dispersibility of the fine pigment in the aqueous pigment dispersion is sufficiently suppressed, and a highly saturated coating composed of the aqueous pigment dispersion. A film can be formed.

  As described above, the block copolymer (I) has a cyclic amine unit content of 5 to 30% by weight (more preferably 5 to 25% by weight, still more preferably 7 to 20% by weight) as a preferred form of the content of each unit. ), 40-80% by weight of nonionic water-soluble units (more preferably 45-75% by weight, more preferably 45-73% by weight), and 0.5-20% by weight of anionic water-soluble units (more preferably 0). 1 to 5 wt%, more preferably 1 to 10 wt%), a cyclic amine unit, a nonionic water-soluble unit, and an anionic water-soluble unit in the same proportion as in the first form, and further nonionic It has the 2nd form containing 10 to 50 weight% (more preferably 15 to 45 weight%, still more preferably 20 to 40 weight%) of water-insoluble unit.

  The block copolymer (I) can be synthesized using a known polymerization method such as living (controlled) radical polymerization. The living radical polymerization methods are roughly classified into ATRP (atom transfer radical polymerization) method, RAFT (reversible addition-fragmentation chain transfer polymerization) method, NMP (nitroxide mediated radical polymerization) method, TERP (organic tellurium mediated radical polymerization). And RTCP (reversible transfer catalytic polymerization) method.

  The ATRP method uses an organic halide as a polymerization initiator, and a polymerization using a transition metal complex consisting of a metal selected from Group 8, Group 9, Group 10 and Group 11 elements and a ligand as a catalyst. It is a method to do. Examples of the organic halide include monofunctional compounds such as ethyl 2-bromopropionate, butyl 2-bromide propionate, 2-bromopropiononitrile, 2-isobutyronitrile bromide, and the like. -Bifunctional compounds such as diethyl dibromoadipate, dimethyl 2,6-dibromopimelate, diethyl 2,6-dibromopimelate, and polyfunctional compounds such as tris (bromomethyl) benzene can be used. As the transition metal complex, complexes of monovalent and zerovalent copper, divalent ruthenium, divalent iron, divalent nickel and the like can be used. For example, when an organic bromide or a sulfonyl bromide compound is used as a polymerization initiator, a transition metal comprising copper bromide, preferably copper contained in cuprous bromide as a central metal and a ligand such as pentamethyldiethylenetriamine. It is preferable to use the complex as a catalyst.

  The RAFT polymerization method is a method using a thiocarbonylthio compound as a chain transfer agent. As the thiocarbonylthio compound, any compound having a thiocarbonylthio group having a dithioester structure or a trithiocarbonate structure can be used without particular limitation.

  The NMP method is a method in which a nitroxide compound or an alkoxyamine compound derived from a nitroxide compound is used as a regulator for controlling polymerization. Examples of the nitroxide compound include 2,2,6,6-substituted-1-piperidinyloxy radical and 2,2,5,5-substituted-1-pyrrolidinyloxy radical, and the substituent is carbon. The alkyl group of number 1-4 is mentioned. Examples of nitroxide compounds include 2,2,6,6-tetramethyl-1-piperidinyl oxide, 2,2,6,6-tetraethyl-1-piperidinyl oxide, 2,2,6,6-tetramethyl. Examples include -4-oxo-1-piperidinyl oxide, 2,2,5,5-tetramethyl-1-pyrrolidinyl oxide, and the like. The nitroxide compound is used in combination with a radical generator. The combination ratio of both is not particularly limited, but may be 0.1 to 10 mol of the radical generator with respect to 1 mol of the nitroxide compound. As the radical generator, general organic peroxides and azo compounds are used.

  The TERP method is a method in which polymerization is performed in the presence of an organic tellurium compound through thermal dissociation of a bond between a tellurium atom and carbon, followed by degenerative chain transfer. Specific examples of the organic tellurium compound include (methylterranylmethyl) benzene, (1-methylterranylethyl) benzene, 1-chloro-4- (1-methylterranylethyl) benzene, 1-trifluoromethyl-4. -(1-methylteranylethyl) benzene, 3,5-bis-trifluoromethyl-1- (1-methylterranylethyl) benzene, 1,2,3,4,5-pentafluoro-6- (1 -Methyl terranyl ethyl) benzene, 2-methyl teranyl propionitrile, (2-methyl teranyl propyl) benzene, methyl 2-methyl teranyl-2-methyl-propionate, ethyl 2-methyl teranyl-2-methyl-propionate, 2 -Methyl teranyl-2-methyl-propionitrile.

  Living radical polymerization is, for example, −100 to 250 ° C., preferably 0 to 200 ° C., more preferably room temperature to 200 ° C., and still more preferably 50 to 150 ° C., without solvent (bulk polymerization) or in a solvent. Can be implemented.

  As the solvent, a solvent inert to the polymerization reaction can be used without any particular limitation. For example, hydrocarbon solvents such as benzene and toluene, ether solvents such as diethyl ether and tetrahydrofuran, and halogenated hydrocarbons such as methylene chloride and chloroform. Solvents, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, alcohol solvents such as methanol, ethanol, propanol, isopropanol, n-butanol and t-butanol, nitrile solvents such as acetonitrile, propionitrile and benzonitrile And ester solvents such as ethyl acetate and butyl acetate, carbonate solvents such as ethylene carbonate and propylene carbonate, and amide solvents such as N, N-dimethylformamide and N, N-dimethylacetamide.

  In order to produce the block copolymer (I) by the living radical polymerization method, a method of sequentially adding a predetermined amount of a raw material compound as a base of each structural unit, a polymer synthesis of one polymer block synthesized in advance is started. Examples of the agent include a method of polymerizing the other polymer block, a method of combining separately polymerized polymer blocks by reaction, and the like. In the case of sequential addition of raw material compounds, it is desirable to charge the next raw material compound when the conversion rate of the raw material compound previously charged is 80 to 95%. The conversion rate is obtained by, for example, gas chromatography, nuclear magnetic resonance spectroscopy, gravimetric method, or the like.

  As a method of polymerizing the other polymer block using one polymer block synthesized in advance as a polymer initiator, for example, at a desired time during polymerization of one polymer block, the temperature is once lowered in a living state, There is a method in which the polymerization is stopped, the raw material compound of one polymer block is distilled off under reduced pressure, and then the raw material compound of the other polymer block is added. The same operation may be performed when polymerizing the third and subsequent polymer blocks. The obtained block copolymer (I) can be rendered water-soluble by neutralization with an alkali agent such as NaOH.

  Living radical polymerization methods are described in, for example, Macromolecules, 1995, 28, 1721-1723; Am. Chem. Soc. 1995, 117, 5614-5615; Chem. Rev. 2001, 101, 3661-3688; Macromolecules, 2000, 33, 4403-4410; Macromolecules, 2006, 39, 8274-8282; Aust. J. Chem. 2005, 58, 379-410; Polymer, 2007, 48, 1-53; HANDBOOK OF RADICAL POLYMERIZATION; Matyjaszewski and TPDavis Ed., Wiley, 2002, p. 661; International Publication No. 2004/014962; JP 2009-256457 A; JP 2007-92014 A; ing.

  The block copolymer (I) thus obtained has a molecular weight (peak) from the viewpoint of enhancing both the saturation of the coating film made of an aqueous pigment dispersion and the coating surface coating film made of a paint prepared using the dispersion. The top molecular weight is preferably in the range of 3000 to 1 million, more preferably 3000 to 500,000, further preferably 4000 to 100,000, particularly preferably 4000 to 50,000, and most preferably 5000 to 30,000. The molecular weight of the block copolymer (I) can be adjusted by appropriately selecting the type and content of each structural unit, the timing of stopping the polymerization reaction, and the like.

  In addition, the block copolymer (I) preferably has an acid value from the viewpoint of enhancing both the saturation of the coating film made of an aqueous pigment dispersion and the coating surface coating film made of a paint prepared using the dispersion. Is 20 mg KOH / g or more, more preferably 20 to 80 mg KOH / g, still more preferably 25 to 75 mg KOH / g, and an amine value of 40 mg KOH / g or more, more preferably 40 to 100 mg KOH / g, still more preferably 42 to 98 mg KOH. / G. One feature of the block copolymer (I) is that it has both an acid value and an amine value. For example, the acid value and the amine value can be determined by appropriately selecting the type and content of each structural unit. It can be adjusted by changing.

  The surface treatment with the surface treatment agent containing the block copolymer (I) is performed, for example, by adding and mixing the surface treatment agent to the finely divided fine pigment dispersion, or by adding the pigment in the presence of the surface treatment agent. This is done by miniaturizing. The surface treating agent is preferably used in a form in which the block copolymer (I) is dissolved or dispersed in water, a water-soluble solvent or a solvent. As the water-soluble solvent, those described above can be used. The amount of the surface treatment agent used is not particularly limited, but the block copolymer (I) is preferably 0.1 to 100 parts by weight, more preferably 100 parts by weight of the finer pigment or the pigment being refined. May be used in an amount of 0.5 to 60 parts by weight, more preferably 1 to 30 parts by weight or less, and particularly preferably 5 to 30 parts by weight.

  The conventional block copolymer needs to be used in an amount of about 100 parts by weight with respect to 100 parts by weight of the pigment in order to fully exert its effect. On the other hand, the block copolymer (I) used in the present invention may of course be used in the amount of about 100 parts by weight as in the conventional case. Can bring. The water-based pigment dispersion of the present invention in which the amount of the block copolymer (I) used is reduced to, for example, 30 parts by weight or less, when preparing a paint according to the use from the dispersion, Selection is relatively easy, and the design freedom of the paint can be increased.

[Optional ingredients]
As long as the water-based pigment dispersion of the present invention does not impair its functions and effects, and considering the poor compatibility when formed into a paint, coating film defects, weather resistance of the coating film, etc., as an optional component, For example, it may contain a resin-type pigment dispersant, a surface active pigment dispersant, an organic pigment derivative, a dispersion aid, and the like. These arbitrary components can be used individually by 1 type or in combination of 2 or more types. These optional components can be added to the pigment dispersion and / or the micronized pigment dispersion being refined simultaneously or separately with the surface treatment agent, for example. When adding simultaneously with a surface treating agent, you may include these arbitrary components in a surface treating agent.

  Specific examples of the resin-type pigment dispersant include, for example, polyurethane, polyester, unsaturated polyamide, phosphoric acid ester, polycarboxylic acid and its amine salt / ammonium salt / alkylamine salt, polycarboxylic acid ester, hydroxyl group-containing polycarboxylic acid ester, Oil-soluble dispersants such as polysiloxane and modified polyacrylate, water-soluble such as (meth) acrylic acid- (meth) acrylic acid ester copolymer, (meth) acrylic acid-styrene copolymer, styrene-maleic acid copolymer Examples include resins and water-soluble polymer compounds. Surfactant type pigment dispersants include naphthalene sulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate, anion activator such as polyoxyethylene alkyl phosphate, nonionic activator such as polyoxyethylene alkyl ether, alkyl Examples include cation activators such as amine salts and quaternary ammonium salts. An organic pigment derivative is a compound having an organic pigment as a basic skeleton and having introduced therein a substituent imparting acidity, a substituent imparting basicity, a neutral substituent, etc. in the molecule, and further improving the dispersibility of the pigment. Can be improved. Furthermore, as a dispersion aid, the performance according to the synthetic resin such as epoxy resin and (meth) acrylic resin which is insoluble in water and solid at room temperature, fiber derivative, rubber derivative, protein derivative, etc. And the like. Since many commercially available products are known for each optional component, it can also be selected from commercially available products.

[Method for producing aqueous pigment dispersion]
As a manufacturing method of the water-based pigment dispersion of the present invention, for example, a first manufacturing method including a miniaturization step and a surface treatment step performed subsequent to the miniaturization step, and a second method including a miniaturized surface treatment step. A manufacturing method etc. are mentioned.

  The first manufacturing method is a method in which the finer pigment and the surface treatment of the finer pigment are separately performed. The micronization step is performed according to the above-described salt milling method, and the pigment, the water-soluble inorganic salt, and the water-soluble solvent are kneaded and the pigment is ground to obtain a first mixture containing the micronized pigment. A general kneader can be used for kneading, and examples of the kneader include a kneader, a two-roll mill, a three-roll mill, a ball mill, an attritor, a sand mill, and a planetary mixer. In the surface treatment step, a surface treatment agent is added to and mixed with the first mixture obtained in the refinement step to obtain a second mixture containing the refined pigment surface-treated with the surface treatment agent.

  For example, the surface treatment agent is added and mixed with stirring to the first mixture stored in the kneader. A surface treating agent contains block copolymer (I), and the usage-amount of a surface treating agent is also as above-mentioned. The total amount of the surface treatment agent may be added at once, or may be added in multiple portions.

  The second production method is a method in which the refinement of the pigment and the surface treatment of the refined pigment are simultaneously performed. In the refined surface treatment step, the pigment, the water-soluble inorganic salt, and the water-soluble solvent are kneaded in the presence of the surface treatment agent according to the above-described salt milling method, and the pigment is ground and treated. To obtain a second mixture containing the micronized pigment surface-treated. The second production method is also performed using a kneader similar to the first production method. A surface treating agent contains block copolymer (I), and the usage-amount of a surface treating agent is also as above-mentioned. The surface treatment agent may be added all at once as in the first production method, or may be added in multiple portions.

  Although the 2nd mixture obtained by the 1st, 2nd manufacturing method may be used as an aqueous pigment dispersion of the present invention as it is depending on a use, the solvent processing process mentioned below to the 2nd mixture may be carried out. And it is preferable to perform only the subsequent water washing step or the water washing step.

  In the solvent treatment step, a solvent that is incompatible with the water-soluble solvent is added to and mixed with the second mixture. By performing the solvent treatment step, the water-soluble solvent and the water-soluble inorganic salt can be efficiently removed in the water washing step, and the time required for the water washing step can be shortened. The solvent incompatible with the water-soluble solvent is at least one selected from the group consisting of alcohol solvents, ketone solvents, ester solvents, ether solvents, aliphatic hydrocarbon solvents, and aromatic hydrocarbon solvents. It can be preferably used.

  Examples of alcohol solvents include butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecanol, cyclohexanol, benzyl alcohol, amyl alcohol, and the like. Examples of ketone solvents include methyl ethyl ketone, methyl isobutyl kenton, cyclohexanone, ethyl amyl ketone, diisobutyl ketone, and methyl cyclohexanone. Examples of ester solvents include ethyl acetate, n-butyl acetate, ethyl lactate, methyl ethoxypropionate, ethyl ethoxypropionate, and the like. Examples of the ether solvent include ethylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate and the like. Examples of the aliphatic hydrocarbon solvent include n-pentane, n-hexane, and n-heptane, and examples of the aromatic hydrocarbon solvent include toluene, o-xylene, m-xylene, and p-xylene. .

  In the water washing step, the water-soluble solvent, the solvent incompatible with the water-soluble solvent, the water-soluble inorganic salt, etc. are removed by washing the second mixture or the second mixture in which the solvent incompatible with the water-soluble solvent is added and mixed. Thus, the aqueous pigment dispersion of the present invention is obtained. For example, washing with water is performed by mixing the second mixture or the second mixture added and mixed with a solvent incompatible with the water-soluble solvent with hot water, and then filtering the liquid material to remove the surface-treated fine pigment. This is carried out by obtaining a solid substance contained in the product and washing it with water. The solid is preferably washed with water until no water-soluble solvent, solvent incompatible with the water-soluble solvent, water-soluble inorganic salt, or the like is detected in the washing solution.

  In the present invention, the aqueous pigment dispersion after the water washing treatment is preferably subjected to a dispersion treatment. The dispersion treatment method is not particularly limited, and for example, the water-based pigment dispersion after the water washing treatment may be stirred and mixed in the presence or absence of a medium and, if necessary, applying a shearing force. Since the water-based pigment dispersion of the present invention has very good dispersibility of the fine pigment, it may be easily dispersible by applying a weak shear force without adding a strong shear force.

  The water-based pigment dispersion of the present invention can be used in the same applications as conventional water-based pigment dispersions. For example, ink for ink jet recording, paint for coating steel plates of automobiles (particularly, top coat), color toner, recording medium, etc. Can be suitably used as stationery, such as electronic paper and writing instruments.

  Hereinafter, the present invention will be described more specifically with reference to production examples, examples, and comparative examples, but the present invention is not limited to the following examples. In the following, “parts” and “%” are based on weight unless otherwise specified. Moreover, the method shown next was used for the measurement of the physical property in a present Example.

[Molecular weight]
Gel permeation chromatography (GPC) was used to measure the molecular weight of the polymer. The GPC system includes an RI detector (trade name: RID-10A), a system controller (trade name: SCL-10A), a pump (trade name: LC-20AD), and GL Science Co., Ltd. manufactured by Shimadzu Corporation. A column oven (trade name: CO705) was used, and Shodex GPC KF-804, GPC KF-802, GPC KF-G (all trade names) manufactured by Showa Denko KK were used as the columns. . The solvent used was tetrahydrofuran, the flow rate was 1 ml / min, the column temperature was 35 ° C., and polystyrene was used as the standard substance.

[Acid value]
The acid value of the polymer was determined by using an automatic titrator (trade name: COM-1600, manufactured by Hiranuma Sangyo Co., Ltd.) and 0.1M water using a sample obtained by dissolving the block copolymer (I) in acetone. It was measured by potentiometric titration with potassium oxide.
[Amine value]
The amine value of the polymer was determined by using an automatic titrator (trade name: COM-550, manufactured by Hiranuma Sangyo Co., Ltd.), and a sample obtained by dissolving the block copolymer (I) in acetic acid. Measured by potentiometric titration with chloracetic acid solution.

[PH]
The pH was measured using a pH meter (trade name: Seven Easy, manufactured by METTLER TOLEDO Co., Ltd.).

[saturation]
Using a bar coater (No. 6, winding diameter 0.15 mm) on a PET film (trade name: Lumirror 100-T60, manufactured by Toray Industries, Inc.) having a thickness of 100 μm, the water-based pigment dispersion is 2 μm in wet film thickness. And then dried at 25 ° C. to prepare a coating film. The reflection hue and saturation of the obtained coating film were measured using a spectral color difference meter (trade name: SE 6000, manufactured by Nippon Denshoku Industries Co., Ltd.). A white plate was applied to the lower surface of the PET film, and the reflected hue was measured with a Hunter Lab color system with a light source C (halogen lamp 12V50W), a viewing angle of 2 °, and a measurement area of 30 mmφ. From the obtained a value and b value, the saturation C value was calculated by the following formula. The white plate has a light source C, a viewing angle of 2 °, and tristimulus values X, Y, and Z in the XYZ color system of 90 ≦ X ≦ 96, 92 ≦ Y ≦ 98, and 100 ≦ Z ≦ 116. A thing was used.
Saturation C = (a ² + b ² ) ^1/2

The dispersibility of the water-based pigment dispersion was determined by the chroma C value. The higher the saturation, the higher the C value, and the lower the saturation, the smaller the C value. Based on the obtained saturation C value, the following criteria were evaluated.
◎: Saturation of 73 or more ... very good ◯: Saturation of 70 or more and less than 73 ... very good x: Saturation of less than 70 ... insufficient

(Production Example 1)
192.8 parts of butyl acrylate (nonionic water-insoluble organic compound), methoxypolyethylene glycol (n≈9) methacrylate (nonionic water-soluble organic compound) 321.9 parts, acrylic acid (anionic water-soluble organic compound) 59. 2. 2 parts N- (2-methylpropyl) -N- (1-diethylphosphono-2,2-dimethylpropyl) -O- (2-carboxylprop-2-yl) hydroxyamine (polymerization modifier) 0 parts, 370 parts of propylene glycol monomethyl ether acetate (reaction solvent) were charged into a 2 L stainless steel separable flask, and the system was heated to 125 ° C. in an oil bath while bubbling and stirring with nitrogen. Polymer block B was synthesized by reacting for 6.5 hours after the completion. When a small amount of the contents were sampled and GPC measurement was performed, the peak top molecular weight was 9570 and Mw / Mn = 1.43.

  Next, 56.1 parts of 4-vinylpyridine (cyclic amine compound) and 50 parts of propylene glycol monomethyl ether acetate (reaction solvent) were added to the flask, followed by reaction at 125 ° C. for 4 hours with nitrogen bubbling and stirring. When the contents were sampled and GPC measurement was performed, the peak top molecular weight was 10140 and Mw / Mn was 1.45.

  Next, the temperature inside the system was raised to 210 ° C., the pressure inside the system was reduced to 2.0 kPa, the solvent was distilled off, and the block copolymer (I) was taken out. When the obtained block copolymer (I) was measured by GPC, the peak top molecular weight was 10990 and Mw / Mn was 1.49. The acid value was 74.0 mgKOH / g, and the amine value was 52.9 mgKOH / g.

  600 parts of the block copolymer obtained in Production Example 1, 46.7 parts of a 48% aqueous sodium hydroxide solution, and 730 parts of ion-exchanged water were charged into a 2 L glass separable flask and stirred at 80 ° C. with a mantle heater. Heating was performed for 3 hours to obtain a surface treatment agent in the form of an aqueous solution.

(Production Example 2 , 4 to 15)
The block copolymer of the present invention was prepared in the same manner as in Production Example 1, except that the types and amounts of the nonionic water-soluble organic compound, the anionic water-soluble organic compound, the nonionic water-insoluble organic compound, and the cyclic amine compound were changed. A polymer (I) (Production Examples 2 , 4 to 12) and a comparative copolymer (Production Examples 13 to 15) were produced.

In addition, the abbreviations described in Table 1 are specifically as follows.
Structural unit (1): Nonionic water-insoluble organic compound (BA: structural unit derived from butyl acrylate, MMA: structural unit derived from methyl methacrylate, MA: structural unit derived from methyl acrylate)
Structural unit (2): Nonionic water-soluble organic compound (MPE; structural unit derived from methoxypolyethylene glycol acrylate)
Structural unit (3): anionic water-soluble organic compound (AA; structural unit derived from acrylic acid)
Structural unit (4): amine compound (DMA; structural unit derived from dimethylaminoethyl acrylate [comparative amine compound], VPy; structural unit derived from 4-pyridine [cyclic amine compound] )

The main materials and equipment used in the following examples and comparative examples are as follows.
[Pigment] Chlorinated copper phthalocyanine pigment (CI Pigment Blue 15: 1), trade name: CYANINE BLUE G-314, manufactured by Sanyo Dye Co., Ltd. [Water-soluble inorganic salt] Neutral anhydrous sodium sulfate, Mitajiri Chemical Industry ( Co., Ltd. [Water-soluble solvent] Diethylene glycol, Mitsubishi Chemical Co., Ltd. [Solvent incompatible with water-soluble solvent] Methyl ethyl ketone, Maruzen Petrochemical Co., Ltd. [Kneading machine] Double-arm kneader, 1L kneader, Co., Ltd. ) Made by Moriyama

Example 1
<Refining process>
600 g of neutral anhydrous sodium sulfate, 60 g of chlorinated copper phthalocyanine pigment, and 132 g of diethylene glycol were charged into a double-arm kneader and kneaded for 10 hours while maintaining the temperature of the mixture inside the kneader at 40 ° C. to obtain magma.

<Surface treatment process>
In the kneader, 18 g of the surface treatment agent comprising the block copolymer of Production Example 1 in a pure amount of the block copolymer (I) is added to the magma obtained in the refinement process (30% of the refined pigment). The magma temperature was maintained at 40 ° C. and kneaded for 3 hours.

<Washing process>
The magma containing the surface-treated fine pigment is stirred and dispersed in 8 L of warm water at 60 ° C., then transferred to Nutsche, filtered, and washed repeatedly until neutral anhydrous sodium sulfate and diethylene glycol are almost completely removed. A paste was obtained.

<Preparation of aqueous pigment dispersion>
From the resulting pigment water paste, 10 g of the refined pigment pure was weighed, put into a 200 mL glass bottle, water and 5 mol / L sodium hydroxide aqueous solution were further added, the refined pigment content was 14% and the pH was 8 After adjusting to 0.5, dispersion treatment was performed for 2 hours using a stainless steel disper to obtain 71.43 g of the aqueous pigment dispersion of the present invention.

(Example 2)
<Miniaturized surface treatment process>
600 g of neutral anhydrous sodium sulfate, 60 g of chlorinated copper phthalocyanine pigment, 111 g of diethylene glycol, and a surface treatment agent obtained by dispersing 18 g of the block copolymer of Production Example 1 in 21 g of diethylene glycol are charged into a double-arm kneader, and the mixture in the kneader Was maintained at 40 ° C. and kneaded for 13 hours to obtain a magma containing the surface-treated fine pigment.

<Solvent treatment process>
In a kneader, 18 g of methyl ethyl ketone (100% with respect to the block copolymer of Production Example 1) was added to the magma after the refined surface treatment step, and the magma temperature was maintained at 40 ° C. and kneaded for 1 hour.

<Preparation of aqueous pigment dispersion>
To the magma after the surface treatment process, add and mix 8 L of warm water at 60 ° C. with stirring, then transfer to Nutsche and filter, and repeat washing with water until neutral anhydrous sodium sulfate, diethylene glycol and methyl ethyl ketone are almost completely removed. A paste was obtained. The obtained pigment water paste was subjected to the same dispersion operation as in the preparation of the aqueous pigment dispersion of Example 1 to obtain 71.43 g of the aqueous pigment dispersion of the present invention.

(Examples 3 and 5 to 13 and Comparative Examples 1 to 3)
Instead of the block copolymer of Production Example 1, the block copolymers of Production Examples 2 and 4 to 12 (Examples 3 and 5 to 13) and the copolymers of Production Examples 13 to 15 (Comparative Examples 1 to 3) A water-based pigment dispersion for use in the present invention and for comparison was obtained in the same manner as in Example 2, except that each was used.
The chroma of the coating film was evaluated for the aqueous pigment dispersions obtained in Examples 2 , 3, 5 to 13 and Comparative Examples 1 to 3. The results are shown in Table 2.

  Those with a saturation evaluation of “◎ (saturation 73 or higher)” are integrated so that the coating film of the water-based pigment dispersion and the PET film cannot be visually discerned, resulting in high saturation, high transparency and high gloss as a whole. , Showed a very clear color. Those with a saturation evaluation of “◯ (saturation of 70 to less than 73)” are integrated so that the coating film of the water-based pigment dispersion and the PET film cannot be visually distinguished, and the saturation evaluation is “◎”. Although it was slightly inferior to the above, it became high chroma, high transparency and high gloss as a whole, and had a clear color. When the chroma evaluation is “× (less than chroma 70)”, the coating film of the water-based pigment dispersion and the PET film can be clearly distinguished visually, the color lacks vividness, and transparency and gloss are not good. It was enough and the impression was poor.

The greater the saturation C value, the higher the actual saturation, and the smaller the saturation C value, the lower the actual saturation. In Examples 2 , 3, 5 to 13, the water-based pigment dispersion of the present invention includes the block copolymer (I) as one reason that the chroma of the coating film of the water-based pigment dispersion has increased to 70 or more. By using the surface treating agent, it is considered that the dispersion average particle diameter of the fine pigment was reduced, and a coating film having high saturation, high transparency, and high gloss was obtained. Further, when the saturation C value is 70 or more, particularly 73 or more, high quality (high saturation and high quality) equivalent to that of a coating film made of a water-based pigment dispersion in final application suitability such as water-based automotive paints and water-based inkjets. There is a tendency to maintain transparency and high gloss.

From Table 2, the surface treatment of the fine pigment with the surface treatment agent containing the block copolymer (I) improves the dispersibility of the fine pigment in the resulting aqueous pigment dispersion, and is formed from the aqueous pigment dispersion. It is considered that the chroma C value of the coated film was remarkably increased to 70 or more, and the coating film was very vividly colored and had high transparency and high gloss.

Claims (14)

Polymer block (A) containing a structural unit derived from a cyclic amine compound, a structural unit derived from a nonionic water-soluble compound and a structural unit derived from an anionic water-soluble compound, and a structural unit derived from the cyclic amine compound A water-based pigment dispersion containing a finely divided pigment surface-treated with a surface treatment agent comprising a block copolymer (I) having no polymer block (B) ,
The cyclic amine compound is 2-vinylpyridine, 4-vinylpyridine, 1-vinylimidazole, 1-vinyl-1H-pyrazole, 1-vinyl-2-imidazoline, 2-vinyl-2-imidazoline, 2-vinylpyrazine, And at least one nitrogen-containing heterocyclic compound selected from the group consisting of 2-vinyl-4,6-diamino-1,3,5-triazine,
The nonionic water-soluble compound is at least one selected from the group consisting of polyalkylene glycol, polyalkylene glycol (meth) acrylate, hydroxyalkyl (meth) acrylate, (meth) acrylamide compound, N-vinylpyrrolidone, and alkylene oxide. A nonionic water-soluble organic compound of
The anionic water-soluble compound is an organic acid compound having a group containing a polymerizable double bond, and at least one acid group selected from the group consisting of a carboxylic acid group, a sulfonic acid group, and a phosphoric acid group,
The block copolymer (I) is a structural unit derived from 5-30% by weight of structural units derived from the cyclic amine compound, 40-80% by weight of structural units derived from the nonionic water-soluble compound, and a structure derived from the anionic water-soluble compound. An aqueous pigment dispersion containing 0.5 to 20% by weight of a unit .   The water-based pigment dispersion according to claim 1, wherein the polymer block (B) further contains a structural unit derived from a nonionic water-insoluble compound.   The water-based pigment dispersion according to claim 1 or 2, wherein the polymer block (B) is a random copolymer. The nonionic water-insoluble compound has at least one hydrophobic group selected from the group consisting of a chain hydrocarbon group, a cyclic hydrocarbon group and an aromatic hydrocarbon group, and a group containing a polymerizable double bond. The water-based pigment dispersion according to claim 2 or 3 , which is a nonionic water-insoluble organic compound. The nonionic water-insoluble organic compound is a chain alkyl (meth) acrylates, cycloalkyl (meth) acrylates, aryl (meth) acrylates, and to claim 4 is at least one selected from the group consisting of styrene compounds The aqueous pigment dispersion described.   The block copolymer (I) is a structural unit derived from the cyclic amine compound in an amount of 5 to 30% by weight, a structural unit derived from the nonionic water-soluble compound in an amount of 40 to 80% by weight, and a structural unit derived from the anionic water-soluble compound. The aqueous pigment dispersion according to claim 2, comprising 0.5 to 20% by weight and 10 to 50% by weight of a structural unit derived from the nonionic water-insoluble compound. The water-based pigment dispersion according to any one of claims 1 to 6 , wherein the block copolymer (I) has an acid value of 20 mgKOH / g or more and an amine value of 40 mgKOH / g or more. A method of manufacturing a water-based pigment dispersion according to any one of claims 1 to 7
Kneading a pigment, a water-soluble inorganic salt, and a water-soluble solvent to grind the pigment to obtain a first mixture containing a refined pigment; and adding and mixing the surface treatment agent to the first mixture And a surface treatment step of obtaining a second mixture containing the fine pigment that has been surface-treated with the surface treatment agent, and a method for producing an aqueous pigment dispersion. A method of manufacturing a water-based pigment dispersion according to any one of claims 1 to 7
The surface treatment agent, the pigment, the water-soluble inorganic salt, and the water-soluble solvent are kneaded, the pigment is ground and subjected to surface treatment, and a fine mixture is obtained that contains the finely pigment that has been surface-treated with the surface treatment agent. A method for producing a water-based pigment dispersion comprising a surface treatment step. By washing the second mixture obtained in the surface treatment step or the refined surface treatment step, or the second mixture containing a solvent incompatible with the water-soluble solvent obtained in the solvent treatment step. The method for producing an aqueous pigment dispersion according to claim 8 or 9 , wherein the water-soluble inorganic salt, the water-soluble solvent, and a solvent that is incompatible with the water-soluble solvent are removed from the second mixture.   Polymer block (A) containing a structural unit derived from a cyclic amine compound, a structural unit derived from a nonionic water-soluble compound and a structural unit derived from an anionic water-soluble compound, and a structural unit derived from the cyclic amine compound A method for producing a water-based pigment dispersion comprising a polymer pigment (B), and a fine pigment that has been surface-treated with a surface treatment agent comprising the block copolymer (I),
  Kneading a pigment, a water-soluble inorganic salt, and a water-soluble solvent to grind the pigment to obtain a first mixture containing a refined pigment; and adding and mixing the surface treatment agent to the first mixture And a surface treatment step for obtaining a second mixture containing the fine pigment that has been surface-treated with the surface treatment agent, and washing the second mixture with water, whereby the water-soluble inorganic salt, the water-soluble solvent, And a method for producing an aqueous pigment dispersion, wherein a solvent incompatible with the water-soluble solvent is removed from the second mixture.   Polymer block (A) containing a structural unit derived from a cyclic amine compound, a structural unit derived from a nonionic water-soluble compound and a structural unit derived from an anionic water-soluble compound, and a structural unit derived from the cyclic amine compound A method for producing a water-based pigment dispersion comprising a polymer pigment (B), and a fine pigment that has been surface-treated with a surface treatment agent comprising the block copolymer (I),
  The surface treatment agent, the pigment, the water-soluble inorganic salt, and the water-soluble solvent are kneaded, the pigment is ground and subjected to surface treatment, and a fine mixture is obtained that contains the finely pigment that has been surface-treated with the surface treatment agent. A water-based pigment dispersion comprising: removing the water-soluble inorganic salt, the water-soluble solvent, and the solvent incompatible with the water-soluble solvent from the second mixture by washing the second mixture with water Body manufacturing method. The method for producing an aqueous pigment dispersion according to any one of claims 8 to 12, further comprising a solvent treatment step of adding and mixing a solvent incompatible with the water-soluble solvent into the second mixture. The solvent incompatible with the water-soluble solvent is at least one selected from the group consisting of alcohol solvents, ketone solvents, ester solvents, ether solvents, aliphatic hydrocarbon solvents, and aromatic hydrocarbon solvents. A method for producing an aqueous pigment dispersion according to claim 13 .