WO2017169840A1 - Pigment dispersant, aqueous pigment dispersion and method for producing aqueous pigment dispersion - Google Patents

Abstract

Provided are: an aqueous pigment dispersion which has excellent pigment dispersibility and is applicable as a starting material for an aqueous ink for inkjet recording, said ink having excellent abrasion resistance without deteriorating ejection stability; and a pigment dispersant. A pigment dispersant which is formed of an acrylic urethane polymer (P) that has a structure derived from a vinyl polymer (V) in a side chain, while having an acid value of 20-80 mgKOH/g, said acrylic urethane polymer (P) being a reaction product of a polyisocyanate component and a polyol component that contains a vinyl polymer (V) having two hydroxyl groups at one end, one or more polyols (a2) selected from the group consisting of polyether polyols, polyester polyols, polyester ether polyols and polycarbonate polyols, and a polyol (a3) having an anionic group; an aqueous pigment dispersion which contains this pigment dispersant, a pigment, a basic compound, water and an organic solvent (S) that has a logP or logKow (octanol/water partition coefficient) within the range of from -1.75 to 2.00; and a method for producing this aqueous pigment dispersion.

Description

Pigment dispersant, aqueous pigment dispersion, and method for producing aqueous pigment dispersion

The present invention relates to a pigment dispersant and an aqueous pigment dispersion using the same.

The ink jet recording method is being considered for use in various production situations of printed materials, for example, for use in the production situations of household printed materials, office printed materials, photographs, outdoor bulletins and the like.
While the application of the ink jet recording method is expanding, the printed matter obtained by the ink jet recording method is a printed image caused by missing pigment due to, for example, friction that may occur when an external force is applied to the surface of the printed image. Unprecedented performance such as scratch resistance, which can prevent discoloration and deterioration of the resin, is required.

The ink capable of producing a printed material having excellent scratch resistance is selected from the group consisting of, for example, a vinyl polymer having two hydroxyl groups at one end, polyether polyol, polyester polyol, polyester ether polyol, and polycarbonate polyol. A polyurethane (C) having a structure derived from a vinyl polymer in a side chain, obtained by reacting a polyol (A) containing at least one polyol (a2) and a polyisocyanate (B), is aqueous. A binder for ink-jet printing ink dispersed in a medium (D), wherein the polyurethane (C) is 1% by mass of the vinyl polymer based on the total mass of raw materials used for the production of the polyurethane (C). It is obtained by using in the range of ˜60% by mass. Ink containing Kujetto printing ink binders and the like (for example, see Patent Document 1.).
The binder is effective in improving the scratch resistance of the printed material. However, when a binder is used, the viscosity of the ink tends to increase even when the solid content concentration of the ink is low. There was a case that it was not one step below the level that I wanted.
Further, the water-based inkjet ink is, for example, a polymer emulsion of a polymer (a) having a sulfonate ion and stabilized in an emulsified state with the sulfonate ion and the following AB block copolymer, Part or all of the counter ion of the sulfonate ion of (a) is composed of an AB block copolymer composed of 90% by mass or more of a methacrylate monomer, and the polymer of A constituting the AB block copolymer The block has a polystyrene-reduced number average molecular weight of 1,000 to 20,000 in the gel permeation chromatography, a dispersity (weight average molecular weight / number average molecular weight) indicating a distribution of the molecular weight of 1.5 or less, and at least It has a carboxy group, and the acid value of the polymer block is 30 to 25 The carboxy group in the structure is neutralized with an alkali, and the polymer block of B constituting the AB block copolymer is at least the quaternary used as the forming component. It has a quaternary ammonium ion group derived from a methacrylate monomer having an ammonium salt group, and at least a part of the counter ion of the sulfonate ion of the polymer (a) is the second polymer block B has. An aqueous solution containing a polymer emulsion, dye and / or pigment, water, and a water-soluble organic solvent, which is a quaternary ammonium ion group and has an ion bond in which the polymer (a) and the AB block copolymer form a pair. Ink jet inks are known (for example, see Patent Document 2).
However, the water-based inkjet ink also tends to have a high viscosity, and since the ink exhibits a non-Newtonian viscosity, there are cases where it is not possible to take a step further in terms of ejection stability.

On the other hand, as an inkjet ink, two isocyanate groups are formed in one end region obtained by reacting a hydroxyl group of a vinyl polymer (A) having two hydroxyl groups in one end region and an isocyanate group of diisocyanate (B). A dispersant obtained by reacting an isocyanate group of a urethane prepolymer (E) having an amine compound primary and / or secondary amino group containing a polyamine (C) with an amine value of 1 to 100 mgKOH / g An inkjet ink containing a dispersant (see Patent Document 3), a hydroxyl group of a vinyl polymer (A) having a fluorine atom and two hydroxyl groups in one terminal region, and a diisocyanate (B) A urethane group having two isocyanate groups in one end region obtained by reacting with an isocyanate group. A dispersant obtained by reacting an isocyanate group of a polymer (E) and a primary and / or secondary amino group of an amine compound containing a polyamine (C), having an amine value of 1 to 100 mgKOH / g An ink-jet ink containing a characteristic dispersant (see Patent Document 4) is known.
Patent Document 5 discloses an inkjet recording containing a pigment (A), an acrylic-urethane resin containing a carboxyl group or a styrene-urethane resin (B) containing a carboxyl group, and a basic substance (C). In the water-based ink, a styrene monomer and / or a (meth) acrylate monomer is polymerized in the presence of a chain transfer agent containing one mercapto group and two hydroxyl groups as the resin (B). Hydrophobic polymer diol (b1), hydrophilic polymer diol (b2) obtained by polymerizing (meth) acrylic acid in the presence of a chain transfer agent containing one mercapto group and two hydroxyl groups, and organic diisocyanate (b3) A water-based ink for ink jet recording using an acrylic-urethane resin containing a carboxyl group having a structure obtained by reacting with a carboxylic acid is described.
However, none of the inks is sufficient in terms of scratch resistance of the printed matter.

International Publication 2012/0773562 Pamphlet Japanese Patent Laying-Open No. 2015-89906 JP 2009-255063 A JP 2014-84422 A JP 2005-239947 A

The problem to be solved by the present invention is used in the production of water-based ink for inkjet recording that can be used in the production of printed matter having excellent scratch resistance without impairing excellent pigment dispersibility and ejection stability. It is to provide a pigment dispersant and an aqueous pigment dispersion.

The present invention is a pigment dispersant containing a polyurethane having an acid value of 20 to 80 having a structure derived from the vinyl polymer (V) in the side chain, wherein the polyurethane is selected from the group consisting of ethers, esters and carbonates. The above problems have been solved by a pigment dispersant characterized by having at least one structure and an aqueous pigment dispersion using the same.

The aqueous pigment dispersion of the present invention using the pigment dispersant of the present invention maintains excellent pigment dispersibility and ejection stability, and can form a printed matter having excellent scratch resistance. It can be used for the production of aqueous inks.

The pigment dispersant of the present invention contains an acrylic-urethane polymer (P) having an acid value of 20 to 80 having a structure derived from the vinyl polymer (V) in the side chain, and the acrylic-urethane polymer (P ) Has one or more structures selected from the group consisting of ethers, esters and carbonates.
The acrylic-urethane polymer (P) used in the present invention is a compound having an acid value of 20 to 80 in which a vinyl polymer (V) structure is grafted as a side chain on a polyurethane structure as a main chain, It has 1 or more types of structures chosen from the group which consists of ether, ester, and carbonate. Specifically, the acrylic-urethane polymer (P) includes a vinyl polymer (V) having two hydroxyl groups at one end, a polyether polyol, a polyester polyol, a polyester ether polyol, and a polycarbonate polyol. Obtained by reacting a polyol (A) containing at least one selected polyol (a2) and a polyol (a3) having a hydrophilic group, a polyisocyanate (B), and, if necessary, a chain extender. The reactants used are used.

The acrylic-urethane polymer (P) is preferably one containing 1% by mass to 70% by mass of the structure derived from the vinyl polymer (V) with respect to the total amount of the acrylic-urethane polymer (P). It is more preferable to use those containing 5% by mass to 50% by mass, and the use of those containing 10% by mass to 35% by mass provides excellent durability such as alkali resistance and excellent ink ejection stability. It is more preferable to achieve both.

The acrylic-urethane polymer (P) is preferably one having a weight average molecular weight in the range of 5000 to 150,000 from the viewpoint of maintaining good ejection stability of the ink. More preferably it is used.

The hydrophilic group can be introduced into the acrylic-urethane polymer (P) by using, for example, a polyol (a3) having a hydrophilic group. For example, an anionic group, a nonionic group, or a cationic group is used. it can. Among these, it is particularly preferable to use an anionic group as the hydrophilic group.

As the anionic group, for example, a carboxy group, a carboxylate group, a sulfonic acid group, a sulfonate group, and the like can be used. Among them, a part or all of the carboxy group and the sulfonic acid group are formed by a basic compound or the like. It is preferable to use a neutralized carboxylate group or sulfonate group in order to obtain a pigment dispersant having good pigment dispersibility. In addition, examples of the nonionic group include a polyoxyethylene structure.

The hydrophilic group is preferably present in the range of 15 mmol / kg to 2000 mmol / kg with respect to the entire acrylic-urethane polymer (P), and preferably in the range of 450 mmol / kg to 1500 mmol / kg. It is more preferable for obtaining a pigment dispersant having dispersibility, storage stability, and ejection stability.

Further, in the present invention, if the polyurethane having the vinyl polymer structure derived from the vinyl polymer (V) in the side chain is used as the acrylic-urethane polymer (P), it has excellent scratch resistance and durability. A water-based ink for inkjet recording capable of forming a printed image is not obtained, and a group consisting of a polyether polyol, a polyester polyol, a polyester ether polyol, and a polycarbonate polyol in the main chain together with the side chain composed of the vinyl polymer structure. It is important to have a structure derived from one or more selected polyols (a2).
The structure derived from the polyol (a2) is, for example, one or more structures selected from the group consisting of ethers, esters, and carbonates, and more specifically, a polyether structure, a polyester structure, a polyester ether structure, and a polycarbonate structure. Can be mentioned.

Here, instead of the acrylic-urethane polymer (P), it does not have one or more structures selected from the group consisting of ethers, esters and carbonates, more specifically, a structure derived from the polyol (a2). When polyurethane which does not have is used, a printed matter having excellent scratch resistance may not be formed.

The structure derived from the polyol (a2) is preferably contained in the range of 5% by mass to 80% by mass with respect to the total amount of the acrylic-urethane polymer (P).

The polyol (A) used in the production of the acrylic-urethane polymer (P) has two hydroxyl groups at one end for the purpose of introducing a vinyl polymer structure into the side chain of the polyurethane structure as the main chain. Polyether polyol, polyester polyol, and polyester ether polyol for the purpose of using the vinyl polymer (V) having an anionic group and the polyol (a3) having an anionic group and imparting excellent scratch resistance to the printed matter It is important to use at least one polyol (a2) selected from the group consisting of polycarbonate polyols.

Examples of the vinyl polymer (V) having two hydroxyl groups at one end used in the production of the acrylic-urethane polymer (P) include various vinyl monomers in the presence of a chain transfer agent having two hydroxyl groups. What is obtained by polymerizing can be used. Specifically, radical polymerization of the vinyl monomer (F) is carried out in the presence of a chain transfer agent (E) having two hydroxyl groups and a mercapto group, and the vinyl monomer starts from the mercapto group. Polymerized ones can be mentioned.

In addition, as the vinyl polymer (V) having two hydroxyl groups at one end, for example, radical polymerization of a vinyl monomer in the presence of a chain transfer agent having a carboxy group and a mercapto group, As a starting point, a polymer obtained by reacting the vinyl monomer with a compound having a hydroxyl group and a glycidyl group can be used.

Since the obtained vinyl polymer (V) has two hydroxyl groups at one end, a urethane bond is formed by reacting these two hydroxyl groups with an isocyanate group of a polyisocyanate (B) described later. be able to.

As the vinyl polymer (V) having two hydroxyl groups at one end, it is easy to control the viscosity when reacting with the polyisocyanate (B), and the acrylic-urethane polymer (P) used in the present invention is produced. From the viewpoint of improving efficiency and improving ink ejection stability, those having a number average molecular weight of 500 to 10,000 are preferably used, and those having a number average molecular weight of 1,000 to 5,000 are more preferably used. .

In addition, as the vinyl polymer (V), a hydrophilic group-containing vinyl polymer may be used from the viewpoint of imparting hydrophilicity to the resulting acrylic-urethane polymer (P) and imparting excellent storage stability. it can.

As the hydrophilic group, an anionic group, a cationic group, and a nonionic group can be used. As the hydrophilic group that may be present in the vinyl polymer (V), any one of an anionic group and a cationic group can be used. Either one or a combination of both is preferable, and a cationic group is more preferable.

As the anionic group, for example, a carboxy group, a carboxylate group, a sulfonic acid group, a sulfonate group, and the like can be used. Among them, a part or all of the carboxy group and the sulfonic acid group are formed by a basic compound or the like. It is preferable to use a neutralized carboxylate group or sulfonate group in order to impart good water dispersion stability. Moreover, as said cationic group, a tertiary amino group etc. can be used, for example.

In addition, the vinyl polymer (V) has two hydroxyl groups at one end from the viewpoint of allowing the vinyl polymer structure derived from the vinyl polymer (V) to be present in the side chain of the acrylic-urethane polymer (P). Other than the above, those having no other hydroxyl group are preferable. Specifically, it is preferable not to use a hydroxyl group-containing vinyl monomer as the vinyl monomer (F) that can be used in the production of the vinyl polymer (V).

As the chain transfer agent that can be used for the production of the vinyl polymer (V) having two hydroxyl groups at one end, for example, a chain transfer agent (E) having two hydroxyl groups and a mercapto group may be used. it can.

Examples of the chain transfer agent (E) having two hydroxyl groups and a mercapto group include 3-mercapto-1,2-propanediol (thioglycerin), 1-mercapto-1,1-methanediol, and 1-mercapto. 1,1-ethanediol, 2-mercapto-1,3-propanediol, 2-mercapto-2-methyl-1,3-propanediol, 2-mercapto-2-ethyl-1,3-propanediol, 1 -Mercapto-2,3-propanediol, 2-mercaptoethyl-2-methyl-1,3-propanediol, 2-mercaptoethyl-2-ethyl-1,3-propanediol and the like can be used. Of these, it is preferable to use 3-mercapto-1,2-propanediol because it has less odor, is excellent in terms of workability and safety, and is versatile.

Examples of the vinyl monomer (F) used in the production of the vinyl polymer (V) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) ) Acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, lauryl Alkyl (meth) acrylates such as (meth) acrylate, stearyl (meth) acrylate, or isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate; phenyl (meth) acrylate, benzyl (meth) acrylate, pheno Aromatic (meth) acrylates such as ciethyl (meth) acrylate and phenoxydiethylene glycol (meth) acrylate; (meth) acrylic acid, β-carboxyethyl (meth) acrylate, 2- (meth) acryloylpropionic acid, crotonic acid, itacon Acid group or acid anhydride group-containing vinyl monomer such as acid, maleic acid, fumaric acid, itaconic acid half ester, maleic acid half ester, maleic anhydride, itaconic anhydride; (meth) acrylamide, N-monoalkyl (meta ) Acrylamide, N, N-dialkyl (meth) acrylamide, N-methylol (meth) acrylamide, N-isopropoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-isobutoxymethyl (meth) acrylamide; 2-Aji Lysinylethyl (meth) acrylate; N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) ) Acrylate, N, N-diethylaminopropyl (meth) acrylate, N- [2- (meth) acryloyloxyethyl] piperidine, N- [2- (meth) acryloyloxyethyl] pyrrolidine, N- [2- (meth) [Acryloyloxyethyl] morpholine, 4- [N, N-dimethylamino] styrene, 4- [N, N-diethylamino] styrene, 2-vinylpyridine; N-methylaminoethyl (meth) acrylate, Nt-butylamino Ethyl (meth) acrylate; aminomethyla Nitrogen-containing vinyl monomers such as relate, aminoethyl acrylate, aminopropyl (meth) acrylate, amino-n-butyl (meth) acrylate, butylvinylbenzylamine, vinylphenylamine, p-aminostyrene, N-phenylmaleimide Nitriles such as (meth) acrylonitrile; fluorine such as 2,2,2-trifluoroethyl (meth) acrylate, 2,2,3,3-pentafluoropropyl (meth) acrylate, perfluorocyclohexyl (meth) acrylate Containing vinyl monomers; vinyl esters such as vinyl acetate, vinyl propionate and vinyl versatate; vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, propyl vinyl ether and butyl vinyl ether; styrene, α-methyls Vinyl compounds having aromatic rings such as tylene and divinylstyrene; isoprene, chloroprene, butadiene, ethylene, tetrafluoroethylene, vinylidene fluoride, N-vinylpyrrolidone; polyoxyethylene monomethyl ether (meth) acrylate, polyoxyethylene monoethyl Polyoxyethylene group-containing vinyl polymers such as ether (meth) acrylate can be used.

As the vinyl monomer (F), it is possible to use one containing at least one selected from the group consisting of the (meth) acrylic acid and the (meth) acrylic acid alkyl ester to react with the chain transfer agent. It is preferable because it is easy to control and production efficiency can be improved.

The polymerization reaction between the chain transfer agent (E) having two hydroxyl groups and a mercapto group and the vinyl monomer (F) is carried out under a solvent such as toluene or methyl ethyl ketone adjusted to a temperature of about 50 ° C. to 100 ° C., for example. The chain transfer agent (E) and the vinyl monomer (F) can be fed all at once or sequentially, and can proceed by radical polymerization. Thus, radical polymerization of the vinyl monomer (F) proceeds from the mercapto group of the chain transfer agent (E) as a starting point, and a vinyl polymer (V) having two hydroxyl groups at one end is produced. Can do. When the vinyl polymer (V) having two hydroxyl groups at one end is produced by the above method, a conventionally known polymerization initiator may be used as necessary.

The vinyl polymer (V) having two hydroxyl groups at one end obtained by the above method is 1% by mass to 70% by mass with respect to the total mass of raw materials used for the production of the acrylic-urethane polymer (P). It is preferably used in the range, more preferably in the range of 5% by mass to 50% by mass, and in the range of 10% by mass to 35% by mass, the printed matter having excellent durability such as alkali resistance. Is preferable in forming. The raw materials used for the production of the acrylic-urethane polymer (P) include the vinyl polymer (V), the polyol (A2) containing the polyol (a2) and (a3), and the polyisocyanate (B). When the chain extender is used, the total mass of the polyol (A), the polyisocyanate (B), and the chain extender is shown. The same applies hereinafter.

In addition, the polyol (a2) used in the production of the acrylic-urethane polymer (P) is an essential component for obtaining a printed matter having excellent scratch resistance. Here, instead of the acryl-urethane polymer (P), the polyol (a2) is not used, the vinyl polymer (V) having two hydroxyl groups at one end, the polyol (a3) having a hydrophilic group, and The pigment dispersant containing polyurethane having a structure derived from the vinyl polymer (V) in the side chain obtained by reacting the polyisocyanate (B) may not be able to obtain a printed matter having excellent scratch resistance. is there.

As the polyol (a2), it is preferable to use one or more selected from the group consisting of polyether polyol, polyester polyol, polyester ether polyol and polycarbonate polyol, and the storage stability and pigment dispersibility of the ink, In order to further improve the scratch resistance, it is preferable to use a polyether polyol.

As the polyether polyol, for example, one obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator can be used.

Examples of the initiator include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, glycerin, trimethylolethane, Trimethylolpropane and the like can be used.

Further, as the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, or the like can be used.

Specifically, it is preferable to use polytetramethylene glycol, polypropylene glycol, or polyethylene glycol as the polyether polyol in order to improve ink ejection stability. As the polyether polyol, one having a number average molecular weight of 1000 to 3000 can be used even further without impairing the excellent pigment dispersibility and ejection stability of the aqueous pigment dispersion and ink jet recording ink. It is more preferable for forming a printed matter having excellent scratch resistance.

Examples of the polyester polyol include a ring-opening polymerization reaction of a cyclic ester compound such as an aliphatic polyester polyol, an aromatic polyester polyol, or ε-caprolactone obtained by esterifying a low molecular weight polyol and a polycarboxylic acid. Polyesters obtained by the above, copolymerized polyesters thereof, and the like can be used.

As the low molecular weight polyol, for example, ethylene glycol, propylene glycol and the like can be used.

As the polycarboxylic acid, for example, succinic acid, adipic acid, sebacic acid, dodecanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, and anhydrides or ester-forming derivatives thereof can be used.

Further, as the polyester ether polyol, for example, a reaction product of a polyether polyol obtained by adding the alkylene oxide to the initiator and a polycarboxylic acid can be used. As the initiator and the alkylene oxide, the same ones exemplified as those usable when the polyether polyol is produced can be used. Moreover, as said polycarboxylic acid, the thing similar to what was illustrated as what can be used when manufacturing the said polyester polyol can be used.

Further, as the polycarbonate polyol, for example, those obtained by reacting a carbonic acid ester and a polyol, or those obtained by reacting phosgene with bisphenol A or the like can be used.

As the carbonate ester, dimethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate, or the like can be used.

Examples of the polyol that can react with the carbonate ester include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3- Butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptane Diol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 3-methyl-1,5-pentanediol, 2- Ethyl-1,3-hexanediol, 2-methyl-1,3-pro Diol, 2-methyl-1,8-octanediol, 2-butyl-2-ethylpropanediol, 2-methyl-1,8-octanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, hydroquinone Relatively low molecular weight dihydroxy compounds such as resorcin, bisphenol-A, bisphenol-F, 4,4′-biphenol, polyether polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene adipate, Polyester polyols such as polyhexamethylene succinate and polycaprolactone can be used.

As the polyol (a2), when forming a printed matter having more excellent scratch resistance without impairing the excellent pigment dispersibility and ejection stability of the aqueous pigment dispersion or the ink jet recording ink, 200 is used. Those having a number average molecular weight of ˜10,000 are preferred, and those having a number average molecular weight in the range of 1,000 to 3,000 are more preferred.

The polyol (a2) is preferably used in the range of 5% by mass to 80% by mass with respect to the total mass of raw materials used for the production of the acrylic-urethane polymer (P). Furthermore, use within the range of 10% by mass to 80% by mass provided much more excellent scratch resistance without impairing the excellent pigment dispersibility and ejection stability of the aqueous pigment dispersion and ink jet recording ink. It is more preferable when forming printed matter.

The polyol (a2) can be used in combination with the vinyl polymer (V) within a specific range without impairing the excellent pigment dispersibility and ejection stability of the aqueous pigment dispersion and ink jet recording ink. It is more preferable to form a printed matter having even more excellent scratch resistance. For example, [(V) / (a2)] = 1/20 to 20/1 is preferably used, and 1/10 to It is more preferable to use in the range of 10/1.

Further, as the polyol (A) used for the production of the acrylic-urethane polymer (P), a polyol (a3) having a hydrophilic group is used in addition to those described above.

As the polyol (a3) having a hydrophilic group, for example, a carboxy group-containing polyol or a sulfonic acid group-containing polyol can be used.

Examples of the carboxy group-containing polyol include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, and the like. However, it is preferable to use 2,2-dimethylolpropionic acid. Moreover, the carboxy group containing polyester polyol obtained by making the said carboxy group containing polyol and various polycarboxylic acids react can also be used.

Examples of the sulfonic acid group-containing polyol include dicarboxylic acids such as 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfophthalic acid, and 5 [4-sulfophenoxy] isophthalic acid, and salts thereof; Polyester polyol obtained by reacting can be used.

The carboxy group-containing polyol and sulfonic acid group-containing polyol are preferably used in the range where the acid value of the acrylic-urethane polymer (P) is 20 to 80 mgKOH / g, and used in the range of 20 to 65 mgKOH / g. It is more preferable to use in the range of 20 to 55 mg KOH / g. If the acid value is 20 mgKOH / g or more, it is effective in making the pigment finer. The acid value referred to in the present invention is a theoretical value calculated based on the amount of an acid group-containing compound such as a carboxy group-containing polyol used in the production of the acrylic-urethane polymer (P).

The hydrophilic group may be neutralized as necessary. For example, if it is an anionic group, part or all of the hydrophilic group may be neutralized with a basic compound or the like.

Examples of basic compounds that can be used for neutralizing the anionic group include organic amines having a boiling point of 85 ° C. or higher, such as ammonia, triethylamine, morpholine, monoethanolamine, diethylethanolamine, sodium hydroxide, potassium hydroxide, and the like. A metal hydroxide containing lithium hydroxide or the like can be used. The basic compound is preferably used in the range of basic compound / anionic group = 0.5 to 2.0 (molar ratio) in order to improve the storage stability of the resulting aqueous pigment dispersion. More preferably, it is used in the range of 0.8 to 1.1 (molar ratio).

The polyol (a3) having a hydrophilic group is preferably used in the range of 1% by mass to 45% by mass with respect to the total mass of raw materials used for the production of the acrylic-urethane polymer (P).

Examples of the polyisocyanate (B) used for the production of the acrylic-urethane polymer (P) include 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, and phenylene. Aromatic polyisocyanates such as diisocyanate, tolylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, trimethylhexamethylene diisocyanate, etc. Aliphatic polyisocyanate And polyisocyanates containing over preparative or an alicyclic structure, xylylene diisocyanate, and araliphatic polyisocyanates, such as tetramethylxylylene diisocyanate, dimer acid diisocyanate, can use a special polyisocyanate and norbornene diisocyanate. Among them, it is preferable to use an aliphatic polyisocyanate from the viewpoint of preventing yellow discoloration, and in order to further improve durability such as scratch resistance and alkali resistance together with the discoloration prevention, an aliphatic cyclic group is used. Preference is given to using structure-containing polyisocyanates.

The acrylic-urethane polymer (P) is, for example, in the absence of a solvent or in the presence of an organic solvent, the vinyl polymer (V) having two hydroxyl groups at one end, a polyether polyol, a polyester polyol, a polyester ether polyol, and Produced by reacting a polyol (A) containing one or more polyols (a2) selected from the group consisting of polycarbonate polyols, a polyol (a3) having an anionic group, and the polyisocyanate (B). can do. The reaction is preferably carried out in the range of 20 ° C. to 120 ° C. for about 30 minutes to 24 hours.

In the reaction of the polyol (A) and the polyisocyanate (B), for example, the equivalent ratio of the isocyanate group of the polyisocyanate (B) to the hydroxyl group of the polyol (A) is 0.8 to 2.5. Preferably, it is carried out in the range of 0.9 to 1.5.

Examples of the organic solvent that can be used in producing the acrylic-urethane polymer (P) include ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; and acetates such as ethyl acetate and butyl acetate. Nitriles such as acetonitrile; amides such as dimethylformamide and N-methylpyrrolidone can be used alone or in combination of two or more.

When producing the acrylic-urethane polymer (P) used in the present invention, a chain extender can be used as necessary for the purpose of further improving the scratch resistance and the like.

As the chain extender that can be used in producing the acrylic-urethane polymer (P), polyamine, other active hydrogen atom-containing compounds, and the like can be used.

Examples of the polyamine include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'- Diamines such as dimethyl-4,4′-dicyclohexylmethanediamine, 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, N-methylaminopropylamine; diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazine, N, N′-dimethylhydrazine, 1,6-hexamethylenebishydrazine; disuccinate Dorazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide; β-semicarbazide propionic acid hydrazide, 3-semicarbazide-propyl-carbazate, semicarbazide-3-semicarbazide methyl-3,5 5-Trimethylcyclohexane can be used, and ethylenediamine is preferably used.

Examples of the other active hydrogen-containing compounds include ethylene glycol, diethylene recall, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, and saccharose. Glycols such as methylene glycol, glycerin and sorbitol; phenols such as bisphenol A, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenylsulfone, hydrogenated bisphenol A, hydroquinone Etc. can be used alone or in combination of two or more within a range in which the storage stability of the aqueous pigment dispersion of the present invention does not decrease.

The chain extender is preferably used, for example, in a range where the equivalent ratio of the amino group and excess isocyanate group of the polyamine is 1.9 or less (equivalent ratio), 0.3 to 1.0 (equivalent It is more preferable to use it in the range of the ratio.

The acrylic-urethane polymer (P) obtained by the above method can be used, for example, by the following method.

[Method 1] An acrylic-urethane polymer (P) obtained by reacting a polyol (A) and a polyisocyanate (B) without neutralizing hydrophilic groups, an organic solvent (S) described later, After mixing and stirring, the organic solvent used for producing the acrylic-urethane polymer (P) is distilled off and used as a pigment dispersant.

[Method 2] A method in which the hydrophilic group of the acrylic-urethane polymer (P) obtained by reacting the polyol (A) with the polyisocyanate (B) is used as it is as a pigment dispersant. .

[Method 3] A mixture obtained by mixing a part or all of the hydrophilic groups of the acrylic-urethane polymer (P) obtained by reacting the polyol (A) with the polyisocyanate (B) is mixed with water. A method in which after the acrylic-urethane polymer (P) is dispersed in water, the organic solvent used in the production of the acrylic-urethane polymer (P) is distilled off as a pigment dispersant.

[Method 4] A mixture obtained by neutralizing some or all of the hydrophilic groups of the acrylic-urethane polymer (P) obtained by reacting the polyol (A) with the polyisocyanate (B) is mixed with water. If necessary, the chain is extended using the chain extender, the acrylic-urethane polymer (P) is dispersed in water, and then the organic solvent used to produce the acrylic-urethane polymer (P) is distilled off. A method of using the resultant as a pigment dispersant.

[Method 5] A reaction product obtained by reacting the polyol (A) and the polyisocyanate (B) and the chain extender as necessary are charged in a reaction vessel in a batch or divided, and chain extension is performed. Acrylic-urethane polymer (P) is produced by reacting, and then water is mixed with water obtained by neutralizing some or all of the hydrophilic groups in the acrylic-urethane polymer (P). A method in which, after dispersing (P) in water, the organic solvent used in producing the acrylic-urethane polymer (P) is distilled off as a pigment dispersant.

In the above [Method 3] to [Method 5], an emulsifier may be used as necessary. Further, when the acrylic-urethane polymer (P) is dispersed in water, a machine such as a homogenizer may be used as necessary.

The pigment dispersant obtained by the above method can be used for the production of an aqueous pigment dispersion.
The aqueous pigment dispersion contains, for example, the pigment dispersant as an essential component, a pigment, water, an organic solvent, and a neutralizing agent that can be used for neutralizing the hydrophilic group of the acrylic-urethane polymer (P). Things can be used.

As the pigment, one or a combination of two or more organic pigments or inorganic pigments can be used. When two or more of the above pigments are used in combination, they may be used simply as a mixture or as a solid solution. As the pigment, either an untreated pigment or a treated pigment can be used.
As the inorganic pigment, for example, carbon black produced by a known method such as iron oxide, contact method, furnace method, thermal method or the like can be used.
Examples of the organic pigment include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazines). Pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye chelates, acidic dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like.

The pigment used in the black ink is, for example, carbon black, No. manufactured by Mitsubishi Chemical Corporation. 2300, no. 2200B, no. 995, no. 990, no. 900, no. 960, No. 980, no. 33, no. 40, No, 45, No. 45L, no. 52, HCF88, MA7, MA8, MA100, etc. are Raven5750, Raven5250, Raven5000, Raven3500, Raven1255, Raven700, etc. manufactured by Columbia, Regal 400R, Regal 330R, Regal 660R, Mull 660R, Mogul manufactured by Cabot Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. are Color Black FW1, FW2, FW2V, FW18, FW200, FW200, S170, U, S150, S35, S150, U , V, 1400U, Special lack 6, the 5, 4, 4A, NIPEX150, NIPEX160, NIPEX170, NIPEX180, NIPEX95, NIPEX90, NIPEX85, NIPEX80, NIPEX75 and the like.

Also, specific examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 120, 128, 129, 138, 150, 151, 154, 155, 174, 180, 185 and the like.

Also, specific examples of pigments used in magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 146, 150, 168, 176, 184, 185, 202, 209, 213 269, 282, C.I. I. Pigment violet 19 and the like.

Also, specific examples of pigments used for cyan ink include C.I. I. Pigment blue 1, 2, 3, 15, 15: 3, 15: 4, 15: 6, 16, 22, 60, 63, 66, and the like.

The pigment may be either dry powder or wet cake, or may be used in combination.

As the pigment, it is preferable to use a pigment having a primary particle size of 25 μm or less, and using a pigment having a primary particle size of 1 μm or less can more effectively suppress the precipitation of the pigment and improve pigment dispersibility. It is more preferable because it is possible. In addition, the measurement of the said primary particle diameter points out the value observed and measured using the transmission electron microscope (TEM).

The particle diameter of the dispersion containing the pigment in the aqueous pigment dispersion of the present invention is preferably 1 μm or less, more preferably 10 nm to 200 nm, and particularly preferably 50 nm to 170 nm.
The particle diameter is a value measured using Nanotrac UPA-150EX (Nikkiso Co., Ltd.). Specifically, in an environment of 25 ° C., about 4 mL of the aqueous pigment dispersion is put in a measurement cell, and the volume average particle diameter (MV) is set to 3 by detecting scattered light of laser light with Nanotrac UPA-150EX. The average value (unit: nm) of the measurement is shown.

Moreover, as water used for the production of the aqueous pigment dispersion, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used. In addition, water sterilized by ultraviolet irradiation or addition of hydrogen peroxide can be used because it can prevent the generation of mold or bacteria when long-term storage of aqueous pigment dispersions and inks using the same. preferable.

An organic solvent (S) having a log Kow (octanol / water partition coefficient) in the range of −1.75 to 2.00 is used as the organic solvent used in the production of the aqueous pigment dispersion. In obtaining an aqueous pigment dispersion and ink jet recording ink capable of forming a printed matter with even better scratch resistance without impairing the excellent pigment dispersibility and ejection stability of the ink jet recording ink and the ink jet recording ink. preferable.
The organic solvent (S) has a high compatibility with the acrylic-urethane polymer (P), and the dispersed particle size of the particles present in the resulting aqueous pigment dispersion is small. It is more preferable to use one having a value of 55 or more and less than 1.50.
The organic solvent (S) may be used as a kneading solvent for kneading the pigment dispersant and a pigment in the production of the aqueous pigment dispersion. It is more preferable for obtaining an aqueous pigment dispersion and ink jet recording ink capable of forming a printed matter having much more excellent abrasion resistance without impairing excellent pigment dispersibility and ejection stability.

The log Kow (octanol / water partition coefficient) is the two phases (the 1-octanol phase and the water phase) when a chemical substance is added to the two solvent phases of 1-octanol and water to achieve an equilibrium state. ) Is a logarithm of the chemical substance concentration ratio and is also expressed as logPow. Pow is a physicochemical index that represents the hydrophobicity (solubility in lipids) of a chemical substance, and is generally described as a logarithmic value (logPow). The smaller the value of log Kow, the more hydrophilic, and the larger the value, the more lipophilic.

In addition, logKow can be simply estimated from the chemical structure of an organic solvent (S) whose document value or the like is not known by using the computer software “Hansen Solubility Parameters in Practice (HSPiP)”. For the organic solvent (S) in the present invention, the value is used for the organic solvent (S) registered in the database of HSPiP version 4.1.07, and for the organic solvent (S) not registered, The value estimated by version 4.1.07 was used.

The organic solvent (S) having a log Kow (octanol / water partition coefficient) in the range of −1.75 to 2.00 can be used alone or in combination of two or more. When two or more organic solvents (S) are used in combination, an organic solvent (log Kow calculated by volume average of two or more organic solvents (S) is adjusted to a range of −1.75 to 2.00 ( S) is preferably used.
Further, by using an organic solvent (S) which is a combination of two or more organic solvents having a log Pow outside the range of -1.75 to 2.00, the pigment dispersibility can be further improved. An aqueous pigment dispersion or ink for ink jet recording can be obtained.

Examples of the organic solvent (S) having a log Kow (octanol / water partition coefficient) in the range of −1.75 to 2.00 alone include, for example, ethylene glycol (log P: −1.36), diethylene glycol (log P: −1) .47), dipropylene glycol (log P: -0.01), tripropylene glycol (log P: -0.19), propylene glycol (log P: -0.92), polypropylene glycol (number average molecular weight 400: log P: 1) .10), glycol solvents such as thiodiglycol (log P: -0.75); 2-propanol (log P: 0.05), 1,2-hexanediol (log P: 0.56), 1,6-hexane Alcohol solvents such as diol (log P: 0.56); acetone (log P: -0.24), dia Tone alcohol (log P: -0.41), ketone solvents such as methyl ethyl ketone (log P: 0.29); ethylene glycol monomethyl ether acetate (log P: 0.12), propylene glycol monoethyl ether acetate (log P: 0.56) Glycol ester solvents such as dipropylene glycol methyl ether acetate (log P: 1.40), propylene glycol diacetate (log P: 0.73), diethylene glycol monoethyl ether acetate (log P: 0.32); log P: -0.20), diethylene glycol monoethyl ether (log P: -0.54), diethylene glycol dimethyl ether (log P: 0.20), diethylene glycol Glycol monobutyl ether (log P: 0.56), dipropylene glycol dimethyl ether (log P: 1.03), diethylene glycol diethyl ether (log P: 0.39) and other glycol ether solvents; N-methylpyrrolidone (log P: -0.38) ) N-ethylpyrrolidone (log P: -0.04), 1,3-dimethylimidazolidinone (log P: -0.69), dimethylformamide (log P: -1.01), 1,3-bis (2- Nitrogen-containing solvents such as hydroxyethyl) -5,5 dimethylimidazolidine-2,4-dione (log P: -1.50); cyclic carbonate solvents such as propylene carbonate (log P: -0.41), dimethyl sulfoxide (LogP: -1.35) and the like.
Among them, as the organic solvent (S), it is preferable to use tripropylene glycol in order to obtain an aqueous pigment dispersion having a further excellent pigment dispersibility.

The organic solvent (S) having a log Kow (octanol / water partition coefficient) in the range of -1.75 to 2.00 is used in a range of 0.1 to 25% by mass with respect to the total amount of the aqueous pigment dispersion. It is preferable to use the ink in the range of 1 to 15% by mass in order to produce an ink having further excellent ejection stability.

The mass ratio [organic solvent (S) / pigment] of the organic solvent (S) and the pigment is in the range of 0.05 to 2 in order to produce an ink with even better ejection stability. Is preferable, and the range of 0.1 to 1.2 is more preferable.

Examples of organic solvents other than the organic solvent (S) include glycols such as triethylene glycol, tetraethylene glycol, polypropylene glycol, polyethylene glycol, and polyoxyalkylene adducts thereof; glycerins such as glycerin and diglycerin, and the like. Is mentioned. These organic solvents may also function as wetting agents.

As a neutralizing agent that can be used in the production of the aqueous pigment dispersion of the present invention, for example, a basic compound is used if the acrylic-urethane polymer (P) has an anionic group. can do.
As the basic compound, known compounds can be used, such as alkali metal hydroxides such as potassium and sodium; carbonates of alkali metals such as potassium and sodium; carbonates such as alkaline earth metals such as calcium and barium. Salts: inorganic basic compounds such as ammonium hydroxide, amino alcohols such as triethanolamine, N, N-dimethanolamine, N-aminoethylethanolamine, dimethylethanolamine, NN-butyldiethanolamine, morpholine Organic basic compounds such as morpholines such as N-methylmorpholine and N-ethylmorpholine, and piperazine such as N- (2-hydroxyethyl) piperazine and piperazine hexahydrate. Among these, as the basic compound, use of an alkali metal hydroxide typified by potassium hydroxide, sodium hydroxide, or lithium hydroxide contributes to lowering the viscosity of the aqueous pigment dispersion, and is used for inkjet recording. It is preferable for further improving the discharge stability of the water-based ink, and it is particularly preferable to use potassium hydroxide.

The neutralization rate of the anionic group possessed by the acrylic-urethane polymer (P) is not particularly limited, but it is generally preferably in the range of 80 to 120%. The neutralization rate referred to in the present invention is a numerical value indicating how much of the basic compound is used relative to the amount necessary for neutralization of all anionic groups in the acrylic-urethane polymer (P). It is.

The aqueous pigment dispersion of the present invention can be produced by the following known dispersion method.
Dispersion method (1): kneading dispersion method that gives a strong shearing force with a kneader Dispersion method (2): medialess dispersion method such as ultrasonic dispersion method Among others, dispersion method (1) is an aqueous pigment dispersion having a high pigment concentration. It is preferable for obtaining a body, and the dispersion method (2) is preferable because there is no fear of contamination due to media wear and it is simple.

Examples of the kneading dispersion method that is the dispersion method (1) include a pigment dispersant containing the acrylic-urethane polymer (P) obtained in [Method 1] and [Method 2], a pigment, water, and an organic solvent (S). Kneading a mixture containing an organic solvent such as a neutralizing agent such as a basic compound usable for neutralizing the hydrophilic group of the acrylic-urethane polymer (P), and kneading obtained in the step 1 And a step 2 of dispersing the product in water.
When the pigment dispersant containing the acrylic-urethane polymer (P) obtained in [Method 2] is used, the organic solvent used in the production of the acrylic-urethane polymer (P) after step 2 can be distilled off. preferable. In the case of the dispersion method (1), even if the mixture has a high solid content concentration, a strong shearing force can be applied by a kneader, so that the pigment particles can be made finer. As a result, the pigment concentration This is preferable because an aqueous pigment dispersion having a high particle size can be obtained.

The hydrophilic group of the acrylic-urethane polymer (P) contained in the pigment dispersant is preferably not previously neutralized with a neutralizing agent such as a basic compound before the kneading step of the step 1. It is preferable for obtaining an aqueous pigment dispersion having pigment dispersibility. The hydrophilic group is preferably neutralized with a neutralizing agent such as a basic compound in the step 1.

In order to give the mixture a strong shearing force which is a merit of the kneading dispersion method, the pigment dispersant, the pigment, water, an organic solvent such as an organic solvent (S), and the hydrophilic group of the acrylic-urethane polymer (P). As a mixture containing a neutralizing agent such as a basic compound that can be used for neutralization, it is preferable to use a mixture having a high solid content. The solid content ratio of the mixture is preferably 20 to 100% by mass, more preferably 30 to 90% by mass, and most preferably 40 to 80% by mass. By using a mixture having a solid content ratio in the above range, the viscosity of the kneaded product can be kept moderately high, the shearing force applied to the kneaded product is increased, the pigment in the kneaded product is crushed, and the present invention The coating of the pigment with the pigment dispersant can proceed.

As the kneading machine that can be used in the step 1, a roll mill, a Henschel mixer, a pressure kneader, an intensive mixer, a Banbury mixer, a planetary mixer, or the like that can give a strong shearing force can be used. It is preferable to use a kneading apparatus having a stirring tank and stirring blades and capable of sealing the stirring tank, rather than an open kneader having no stirring tank such as a roll. Examples of such an apparatus include a Henschel mixer, a pressure kneader, a Banbury mixer, a planetary mixer, and the like, and a planetary mixer is particularly preferable.
In the step of kneading the mixture having a high solid content ratio, the viscosity of the kneaded product may vary within a relatively wide range. The planetary mixer can be kneaded in a wider range of viscosity than a two-roller or the like. Further, in the course of the kneading process, by supplying a solvent such as water and vacuum distillation in the planetary mixer, the viscosity of the kneaded product during the kneading and the shearing force on the kneaded product are adjusted. Adjustment can be performed easily.

Step 2 of dispersing the kneaded material obtained in Step 1 in water is not particularly limited and can be performed by a known method. As step 2, for example, after the kneaded product is produced, the mixture is stirred while supplying a solvent such as water, whereby an aqueous pigment dispersion in which pigments are dispersed in water can be obtained. Further, the kneaded product obtained through the above step 1 is taken out from the kneader, put into the stirrer, and then stirred while supplying water or the like to obtain an aqueous pigment dispersion in which the pigment or the like is dispersed in water. be able to.
The water may be supplied in a necessary amount to the kneaded product, but may be supplied continuously or intermittently.
The stirrer is not particularly limited, and a kneader such as the roll mill, Henschel mixer, pressure kneader, intensive mixer, Banbury mixer, planetary mixer, etc. can be used as it is, as well as a paint shaker, bead mill, sand mill, ball mill, attritor. , Basket mills, sand grinders, dyno mills, disperse mats, SC mills, spike mills, agitator mills, juice mixers, high pressure homogenizers, ultrasonic homogenizers, nanomizers, resolvers, dispersers, high-speed impeller dispersers, and the like.
The aqueous pigment dispersion obtained by the dispersion method (1) may then be subjected to a centrifugal separation treatment or a filtration treatment.

As the medialess dispersion method as the dispersion method (2), for example, a pigment and a pigment dispersant containing the acrylic-urethane polymer (P) obtained by the [Method 3], [Method 4] or [Method 5] And a method of dispersing a mixture containing the organic solvent (S) and water.
In the medialess dispersion method, the pigment dispersant containing the acrylic-urethane polymer (P), the organic solvent (S), water, and other components that can be used as necessary are charged and dispersed together. Therefore, it is a suitable method for producing an aqueous pigment dispersion.
Specific examples of the medialess dispersion method include an ultrasonic dispersion method, a high-speed disk impeller, a colloid mill, a roll mill, a high-pressure homogenizer, a nanomizer, an optimizer, and the like. The ultrasonic dispersion method is preferable for maintaining.
It is preferable to mix and stir the pigment and water before ultrasonic dispersion in order to improve the fluidity of the aqueous pigment dispersion and prevent the pigment from settling. The viscosity range of the aqueous pigment dispersion is preferably from 0.1 to 100 mPa · s, more preferably from 0.5 to 50 mPa · s, in order to ensure suitable fluidity of the aqueous pigment dispersion. 5 to 30 mPa · s is even more preferable, and 1.0 to 20 mPa · s is most preferable. The pigment concentration of the aqueous pigment dispersion is preferably 1 to 30% by mass, more preferably 1 to 25% by mass, still more preferably 3 to 20% by mass, and most preferably 5 to 20% by mass.

The conditions for ultrasonic irradiation are not particularly limited, but it is preferably performed at an output of 100 to 3000 W and a frequency of 15 to 40 kHz, more preferably at an output of 150 to 2000 W and a frequency of 15 to 30 kHz.
In addition, the time for performing the ultrasonic irradiation may be as long as necessary to substantially uniformly disperse the pigment particles in the water-based ink. For example, it is usual to give an electric energy of 0.5 to 1000 W · h / g with respect to the mass of the pigment contained in the aqueous pigment dispersion.
The temperature of the aqueous pigment dispersion to be irradiated with ultrasonic waves is not particularly limited, but it is preferable to apply ultrasonic waves while controlling the aqueous ink so that the freezing point is from 70 ° C. to 70 ° C.
The aqueous pigment dispersion obtained by the dispersion method (2) may then be subjected to a centrifugal separation treatment or a filtration treatment.

Although the aqueous pigment dispersion obtained in this manner depends on the application, it is usually preferred that the pigment concentration is adjusted to be 10 to 30% by mass because the ink can be easily diluted. When producing an ink using the aqueous pigment dispersion, a water-soluble solvent, a solvent such as water, an additive to be described later, and the like are used as appropriate according to the desired ink application and physical properties. Ink can be obtained only by diluting the pigment concentration to 0.1 to 20% by mass.

The water-based pigment dispersion is diluted to a desired concentration, and is used in various fields such as the paint field for automobiles and building materials, the printing ink field such as offset ink, gravure ink, flexo ink, silk screen ink, and ink jet recording ink field. Can be used for applications.
When the aqueous pigment dispersion of the present invention is applied to a water-based ink for inkjet recording, a water-soluble solvent, water, a binder, a drying inhibitor, a penetrating agent, a surfactant, a preservative, a viscosity modifier, and a pH, if necessary. A regulator, a chelating agent, a plasticizer, an antioxidant, an ultraviolet absorber and the like can be used. The water-based ink for inkjet recording obtained by the above method may be subjected to a centrifugal separation process or a filtration process thereafter.
As the binder, for example, a urethane resin or an acrylic resin can be used, and among them, an acrylic-urethane polymer having a structure derived from a vinyl polymer in the side chain is preferably used.

The drying inhibitor can be used for the purpose of preventing ink drying. The content of the drying inhibitor in the ink is preferably 3 to 50% by mass.
The drying inhibitor is not particularly limited, but is preferably one that is miscible with water and can prevent clogging of an inkjet printer head. For example, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, triethylene glycol mono-n-butyl ether, polyethylene glycol having a molecular weight of 2000 or less, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propylene glycol, isopropylene glycol Isobutylene glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, mesoerythritol, pentaerythritol, and the like. Among them, the inclusion of glycerin and triethylene glycol is safe and has an excellent effect on ink drying and ejection performance.
In addition, the said drying inhibitor can use the same thing as the above-mentioned organic solvent (S) used with an aqueous pigment dispersion. Therefore, when the aqueous pigment dispersion already contains an organic solvent (S), the organic solvent (S) can also serve as a drying inhibitor.

The penetrant can be used for the purpose of improving the permeability to a recording medium and adjusting the dot diameter on the recording medium.
Examples of the penetrant include lower alcohols such as ethanol and isopropyl alcohol; glycol monoethers of alkyl alcohols such as ethylene glycol hexyl ether, diethylene glycol butyl ether, and propylene glycol propyl ether. The content of the penetrant in the ink is preferably 0.01 to 10% by mass.

The surfactant can be used to adjust ink characteristics such as surface tension. The surfactant is not particularly limited, and includes various anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, and the like. Among these, anionic interfaces Activators and nonionic surfactants are preferred.

Examples of the anionic surfactant include alkylbenzene sulfonate, alkylphenyl sulfonate, alkylnaphthalene sulfonate, higher fatty acid salt, sulfate of higher fatty acid ester, sulfonate of higher fatty acid ester, higher alcohol ether. Sulfate salts and sulfonates of the above, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, etc. Specific examples include dodecylbenzene sulfonate, isopropyl naphthalene sulfonate, monobutylphenylphenol monosulfonate, monobutylbiphenyl sulfonate, dibutylphenylphenol disulfate. Such as phosphate salt can be mentioned.

Nonionic surfactants include, for example, polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester , Polyoxyethylene glycerin fatty acid ester, polyglycerin fatty acid ester, sucrose fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene fatty acid amide, fatty acid alkylolamide, alkyl alkanolamide, acetylene glycol, oxyethylene adduct of acetylene glycol, Polyethylene glycol polypropylene glycol block copolymer, etc. Among these, polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl ether, polyoxyethylene fatty acid ester, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, Fatty acid alkylolamide, acetylene glycol, oxyethylene adduct of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymer are preferred.

Other surfactants include silicone surfactants such as polysiloxane oxyethylene adducts; fluorine surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers. Biosurfactants such as spicrispolic acid, rhamnolipid, lysolecithin and the like can also be used.

The surfactants can be used alone or in combination of two or more. When the surfactant is used, the amount used is preferably in the range of 0.001% to 5% by weight, more preferably 0.001% to 1.5% by weight, based on the total weight of the ink. The range is preferably 0.01% by mass to 1% by mass.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

[Synthesis Example 1] Synthesis of vinyl polymer (V-1) In a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen introduction tube, 2100 parts by mass of methyl ethyl ketone was charged, and then 507 parts by mass of cyclohexyl methacrylate. 118 parts by weight of 2-ethylhexyl methacrylate, 218 parts by weight of methyl methacrylate, 31 parts by weight of n-butyl acrylate, 26 parts by weight of 3-mercapto-1,2-propanediol, 2,2′-azobis (2-methylpropionitrile) ) 0.45 parts by mass were supplied and reacted to obtain a methyl ethyl ketone solution of a vinyl polymer (V-1) having a number average molecular weight of 3000.

[Synthesis Example 2] Synthesis of vinyl polymer (V-2) In a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen introduction tube, 2100 parts by mass of methyl ethyl ketone was charged, and then 524 parts by mass of cyclohexyl methacrylate. Styrene 87 parts by mass, phenoxyethyl acrylate 263 parts by mass, 3-mercapto-1,2-propanediol 26 parts by mass, 2,2′-azobis (2-methylpropionitrile) 0.45 parts by mass, By reacting, a methyl ethyl ketone solution of a vinyl polymer (V-2) having a number average molecular weight of 3000 was obtained.

[Synthesis Example 3] Synthesis of vinyl polymer (V-3) Into a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen introduction tube was charged 2100 parts by mass of methyl ethyl ketone, and then 655 parts by mass of cyclohexyl methacrylate. 219 parts by mass of lauryl methacrylate, 26 parts by mass of 3-mercapto-1,2-propanediol and 0.45 parts by mass of 2,2′-azobis (2-methylpropionitrile) A methyl ethyl ketone solution of a vinyl polymer (V-3) having an average molecular weight of 3000 was obtained.

[Synthesis Example 4] Synthesis of vinyl polymer (V-4) Into a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen introduction tube was charged 2100 parts by mass of methyl ethyl ketone, and then 524 parts by mass of cyclohexyl methacrylate. , 175 parts by mass of n-butyl acrylate, 175 parts by mass of acryloylmorpholine, 26 parts by mass of 3-mercapto-1,2-propanediol, 0.45 parts by mass of 2,2′-azobis (2-methylpropionitrile) Then, a methyl ethyl ketone solution of a vinyl polymer (V-4) having a number average molecular weight of 3000 was obtained.

[Synthesis Example 5] Synthesis of vinyl polymer (V-5) Into a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen introduction tube was charged 2100 parts by mass of methyl ethyl ketone, and then 515 parts by mass of cyclohexyl methacrylate. 202 parts by mass of n-butyl acrylate, 157 parts by mass of dimethylaminoethyl methacrylate, 26 parts by mass of 3-mercapto-1,2-propanediol, 0.45 parts by mass of 2,2′-azobis (2-methylpropionitrile) Was supplied and reacted to obtain a methyl ethyl ketone solution of a vinyl polymer (V-5) having a number average molecular weight of 3000. The amine value of this vinyl polymer (V-5) was 82 mgKOH / g.

[Synthesis Example 6] Synthesis of vinyl polymer (V-6) Into a four-necked flask equipped with a thermometer, a stirrer, a reflux condenser and a nitrogen introduction tube was charged 2100 parts by mass of methyl ethyl ketone, and then 378 parts by mass of cyclohexyl methacrylate. 244 parts by mass of n-butyl acrylate, 252 parts by mass of methacrylic acid, 26 parts by mass of 3-mercapto-1,2-propanediol, 0.45 parts by mass of 2,2′-azobis (2-methylpropionitrile) Then, a methyl ethyl ketone solution of a vinyl polymer (V-6) having a number average molecular weight of 3000 was obtained. The acid value of this vinyl polymer (V-6) was 182.5 mgKOH / g.

Example 1 Production of Pigment Dispersant (P-1) The vinyl polymer (V-) obtained in Synthesis Example 1 in a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube and a stirrer. 1) 2850 parts by weight of a methyl ethyl ketone solution, 845 parts by weight of polypropylene glycol (number average molecular weight 2000), 380 parts by weight of 2,2-dimethylolpropionic acid and 770 parts by weight of isophorone diisocyanate in the presence of 855 parts by weight of methyl ethyl ketone at 80 ° C. For 10 hours to obtain a methyl ethyl ketone solution of acrylic-urethane polymer (P-1) having a weight average molecular weight of 33,000. The acid value of the acrylic-urethane polymer (P-1) was 55 mgKOH / g.

Next, 6650 parts by mass of tripropylene glycol as an organic solvent (S) was added to the methyl ethyl ketone solution of the acrylic-urethane polymer (P-1), and the mixture was sufficiently stirred. The pigment dispersant (P-1) comprising the tripropylene glycol solution of the acryl-urethane polymer (P-1) was obtained by adjusting and adding tripropylene glycol so that the concentration of) was 30% by mass.

[Example 2] Production of pigment dispersant (P-2) The same procedure as in Example 1 was conducted except that the vinyl polymer (V-2) was used instead of the vinyl polymer (V-1). By the method, a pigment dispersant (P-2) comprising a tripropylene glycol solution of an acrylic-urethane polymer (P-2) having a weight average molecular weight of 32000 and an acid value of 55 mgKOH / g was obtained.

Example 3 Production of Pigment Dispersant (P-3) Same as Example 1 except that the vinyl polymer (V-3) was used instead of the vinyl polymer (V-1). By the method, a pigment dispersant (P-3) composed of a tripropylene glycol solution of an acrylic-urethane polymer (P-3) having a weight average molecular weight of 31,000 and an acid value of 55 mgKOH / g was obtained.

[Example 4] Production of pigment dispersant (P-4) The same procedure as in Example 1 was conducted except that the vinyl polymer (V-4) was used instead of the vinyl polymer (V-1). By the method, a pigment dispersant (P-4) comprising a tripropylene glycol solution of an acrylic-urethane polymer (P-4) having a weight average molecular weight of 33,000 and an acid value of 55 mgKOH / g was obtained.

[Example 5] Production of pigment dispersant (P-5) The vinyl polymer (V-) obtained in Synthesis Example 5 in a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube and a stirrer. 5) 2850 parts by weight of methyl ethyl ketone solution, 1253 parts by weight of polypropylene glycol (number average molecular weight 2000), 207 parts by weight of 2,2-dimethylolpropionic acid and 535 parts by weight of isophorone diisocyanate in the presence of 855 parts by weight of methyl ethyl ketone at 80 ° C. For 10 hours to obtain a methyl ethyl ketone solution of an acrylic-urethane polymer (P-5) having a weight average molecular weight of 35,000. The amine value of the acrylic-urethane polymer (P-5) was 25 mgKOH / g, and the acid value was 30 mgKOH / g.

Next, 6650 parts by mass of tripropylene glycol as an organic solvent (S) was added to the methyl ethyl ketone solution of the acrylic-urethane polymer (P-5), and the mixture was sufficiently stirred. The pigment dispersant (P-5) comprising the tripropylene glycol solution of the acrylic-urethane polymer (P-5) was prepared by adding and adjusting tripropylene glycol so that the concentration of) was 30% by mass.

[Example 6] Production of pigment dispersant (P-6) The vinyl polymer (V-) obtained in Synthesis Example 6 in a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube and a stirrer. By reacting 2850 parts by mass of the methyl ethyl ketone solution of 6), 1743 parts by mass of polypropylene glycol (number average molecular weight 2000) and 252 parts by mass of isophorone diisocyanate in the presence of 855 parts by mass of methyl ethyl ketone at 80 ° C. for 10 hours, A methyl ethyl ketone solution of 30000 acrylic-urethane polymer (P-6) was obtained. The acid value of the acrylic-urethane polymer (P-6) was 55 mgKOH / g.

Next, 6650 parts by mass of tripropylene glycol as an organic solvent (S) is added to the methyl ethyl ketone solution of the acrylic-urethane polymer (P-6) and stirred sufficiently. Then, the methyl ethyl ketone is distilled off, and the acrylic-urethane polymer (P- A pigment dispersant (P-6) comprising a tripropylene glycol solution of the acrylic-urethane polymer (P-6) was obtained by adding and adjusting tripropylene glycol so that the concentration of 6) was 30% by mass.

[Comparative Example 1] Production of Pigment Dispersant (P-7) The vinyl polymer (V-) obtained in Synthesis Example 1 was prepared in a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer. By reacting 2915 parts by weight of methyl ethyl ketone solution 1) with 190 parts by weight of 2,2-dimethylolpropionic acid and 365 parts by weight of isophorone diisocyanate at 80 ° C. for 10 hours, an acrylic-urethane polymer (P- A methyl ethyl ketone solution of 7) was obtained. The acid value of the acrylic-urethane polymer (P-7) was 55 mgKOH / g.

Next, 3336 parts by mass of tripropylene glycol as an organic solvent (S) was added to the methyl ethyl ketone solution of the acrylic-urethane polymer (P-7) and stirred sufficiently. Then, the methyl ethyl ketone was distilled off, and the acrylic-urethane polymer (P- 7) The pigment dispersant (P-7) comprising the acrylic-urethane polymer (P-7) and the tripropylene glycol solution of tripropylene glycol is adjusted by adding tripropylene glycol so that the concentration of 7) is 30% by mass. Got.

[Comparative Example 2] Production of Pigment Dispersant (P-8) The vinyl polymer (V-) obtained in Synthesis Example 5 in a container purged with nitrogen equipped with a thermometer, a nitrogen gas inlet tube and a stirrer. 5) By reacting 2880 parts by mass of the methyl ethyl ketone solution, 84 parts by mass of 2,2-dimethylolpropionic acid and 196 parts by mass of isophorone diisocyanate at 80 ° C. for 10 hours, an acrylic-urethane polymer (P— A methyl ethyl ketone solution of 9) was obtained. The amine value of the acrylic-urethane polymer (P-8) was 25 mgKOH / g, and the acid value was 30 mgKOH / g.

Next, 2668 parts by mass of tripropylene glycol as an organic solvent (S) was added to the methyl ethyl ketone solution of the acrylic-urethane polymer (P-8) and the mixture was sufficiently stirred. The pigment dispersant (P-8) comprising the tripropylene glycol solution of the acryl-urethane polymer (P-8) was obtained by adding and adjusting tripropylene glycol so that the concentration of

[Comparative Example 3] Production of Pigment Dispersant (P-9) The vinyl polymer (V-) obtained in Synthesis Example 5 in a container purged with nitrogen equipped with a thermometer, nitrogen gas inlet tube and stirrer. 5) By reacting 2850 parts by weight of the methyl ethyl ketone solution, 1743 parts by weight of polypropylene glycol (number average molecular weight 2000), and 252 parts by weight of isophorone diisocyanate in the presence of 855 parts by weight of methyl ethyl ketone at 80 ° C. for 10 hours, A methyl ethyl ketone solution of an acrylic-urethane polymer (P-9) having a molecular weight of 34000 was obtained. The amine value of the acrylic-urethane polymer (P-9) was 25 mgKOH / g.

Next, 6650 parts by mass of tripropylene glycol as an organic solvent (S) was added to the methyl ethyl ketone solution of the acrylic-urethane polymer (P-9) and stirred sufficiently, and then the methyl ethyl ketone was distilled off to obtain an acrylic-urethane polymer (P-9). The pigment dispersant (P-9) composed of a tripropylene glycol solution of the acrylic-urethane polymer (P-9) was obtained by adjusting and adding tripropylene glycol to a concentration of 30% by mass.

[Comparative Example 4] Production of Pigment Dispersant (P-10) The vinyl polymer (V-) obtained in Synthesis Example 6 in a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer. In the presence of 2915 parts by mass of methyl ethyl ketone solution 6) and 64 parts by mass of isophorone diisocyanate, the mixture was reacted at 80 ° C. for 10 hours to obtain a methyl ethyl ketone solution of acrylic-urethane polymer (P-10) having a weight average molecular weight of 30,000. The acid value of the acrylic-urethane polymer (P-10) was 55 mgKOH / g.

Next, 2200 parts by mass of tripropylene glycol as an organic solvent (S) was added to the methyl ethyl ketone solution of the acrylic-urethane polymer (P-10) and stirred sufficiently, and then the methyl ethyl ketone was distilled off to obtain an acrylic-urethane polymer (P-10 The pigment dispersant (P-10) comprising the tripropylene glycol solution of the acrylic-urethane polymer (P-10) was obtained by adding and adjusting tripropylene glycol so that the concentration of) was 30% by mass.

In Tables 1 and 2, PPG represents polypropylene glycol, DMPA represents 2,2-dimethylolpropionic acid, IPDI represents isophorone diisocyanate, and TPG represents tripropylene glycol.

Example 7
(Production method of blue aqueous pigment dispersion)
(Process 1)
Pigment FASTOGEN Blue TGR [manufactured by DIC Corporation C.I. I. Pigment Blue 15: 3] 5000 parts by mass, a pigment dispersant containing a tripropylene glycol solution of the acrylic-urethane polymer (P-1) obtained in Example 1 above, 5000 parts by mass, and a 34% by mass potassium hydroxide aqueous solution 242. Six parts by mass were charged into a planetary mixer PLM-V-50V (manufactured by Inoue Seisakusho Co., Ltd.) in a container 50L, and the jacket was heated. After the temperature in the kettle reached 40 ° C., kneading was performed for 2 hours to obtain a kneaded product.

(Process 2)
To the kneaded product, a total amount of 13300 parts by mass of ion-exchanged water heated to 40 ° C. was added over 2 hours to obtain an aqueous pigment composition having a pigment concentration of 21.2% by mass.
While adding 1500 parts by mass of tripropylene glycol and 8258 parts by mass of ion-exchanged water little by little to the aqueous pigment composition obtained by the above method, the mixture was stirred with a dispersion stirrer to obtain a blue aqueous dispersion. The pigment concentration in this aqueous dispersion was 15.0% by mass.
Next, the aqueous dispersion was passed through a continuous centrifuge (H-600S, 2 L capacity, manufactured by Kokusan Co., Ltd.), centrifuged at a centrifugal force of 18900 G and a residence time of 10 minutes, and then a filter having an effective pore size of 0.5 μm. A blue water-based pigment dispersion was obtained by performing a filtration treatment according to 1. The pigment concentration of this aqueous pigment dispersion was 14.5% by mass.

(Method for producing water-based ink for inkjet recording)
The blue aqueous pigment dispersion obtained above, 2-pyrrolidinone, triethylene glycol monobutyl ether, glycerin, a surfactant (Surfinol 440, manufactured by Air Products) and ion-exchanged water are blended as follows. By mixing, an aqueous ink for inkjet recording having a pigment concentration of 2% by mass and a resin solid content derived from the pigment dispersant (P-1) of 0.6% by mass was prepared.
Blue aqueous pigment dispersion (pigment concentration 14.5% by mass); 13.8 g
・ 2-Pyrrolidinone; 8g
・ Triethylene glycol monobutyl ether; 8g
・ Glycerin; 3g
・ Surfactant (Surfinol 440, manufactured by Air Products); 0.5 g
・ Ion exchange water; 66.7 g

[Examples 8 to 12 and Comparative Examples 5 to 8]
(Production method of blue aqueous pigment dispersion)
An aqueous pigment dispersion and an aqueous ink for inkjet recording were prepared in the same manner as in Example 7 except that the blending and blending ratios described in Tables 3 and 4 were changed.

[Binder production example]
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 285 parts by mass of the methyl ethyl ketone solution of the vinyl polymer (V-1) obtained in Synthesis Example 1 and polypropylene glycol (number average molecular weight) 2000) 84 parts by mass, 38 parts by mass of 2,2-dimethylolpropionic acid and 77 parts by mass of isophorone diisocyanate were reacted in the presence of 86 parts by mass of methyl ethyl ketone at 80 ° C. for 10 hours to obtain an acrylic having a weight average molecular weight of 33,000. A methyl ethyl ketone solution of urethane polymer (B) was obtained. The acid value of the acrylic-urethane polymer (B) was 55 mgKOH / g.

Next, by adding 32.6 parts by mass of a 48% by mass aqueous potassium hydroxide solution to the methyl ethyl ketone solution of the acrylic-urethane polymer (B), part or all of the carboxy groups of the acrylic-urethane polymer are neutralized, Further, 688 parts by mass of water was added and sufficiently stirred to obtain an aqueous dispersion of acrylic-urethane polymer.

Next, methylethylketone is removed (solvent-removed) from the acrylic-urethane polymer aqueous dispersion, and water is added to adjust the non-volatile content to 25% by mass, thereby adjusting the acrylic-urethane polymer (B) aqueous dispersion. Obtained.

[Comparative Example 9]
(Production method of blue aqueous pigment dispersion)
(Process 1)
1500 parts by mass of vinyl polymer Z (weight average molecular weight 11000, acid value 156 mgKOH / g) obtained by polymerizing 74 parts by mass of styrene, 11 parts by mass of acrylic acid and 15 parts by mass of methacrylic acid, pigment FASTOGEN Blue TGR [DIC C.C. I. Pigment Blue 15: 3] 5000 parts by mass, 2600 parts by mass of diethylene glycol, and 688 parts by mass of a 34% by mass aqueous potassium hydroxide solution were charged into a planetary mixer PLM-V-50V (manufactured by Inoue Seisakusho Co., Ltd.) in a container 50L. The jacket was warmed. After the temperature in the kettle reached 80 ° C., kneading was performed for 4 hours to obtain a kneaded product.

(Process 2)
To the kneaded product, ion exchanged water heated to 60 ° C. in a total amount of 8000 parts by mass was added over 2 hours to obtain an aqueous pigment composition having a non-volatile content of 37.9% by mass.

The aqueous pigment composition obtained by the above method was stirred with a dispersion stirrer while adding 2400 parts by mass of diethylenelene glycol and 14300 parts by mass of ion-exchanged water little by little to obtain a blue aqueous pigment dispersion. The pigment concentration in this aqueous pigment dispersion was 15.0% by mass.

Next, the aqueous pigment dispersion was passed through a continuous centrifuge (Kokusan Co., Ltd., H-600S, 2 L capacity) and centrifuged at a centrifugal force of 18900 G and a residence time of 10 minutes, and then an effective pore size of 0.5 μm was obtained. A blue aqueous pigment dispersion was obtained by performing a filtration treatment with a filter. The pigment concentration of this aqueous pigment dispersion was 14.8% by mass.

By using the blue aqueous pigment dispersion obtained above and mixing the following components, an aqueous ink for inkjet recording having a pigment concentration of 2% by mass was prepared. The solid content of the resin derived from the pigment dispersant and the binder described later was 1.2% by mass. Blue aqueous pigment dispersion (pigment concentration: 14.8% by mass); 13.5 g
・ 2-Pyrrolidinone; 8g
・ Triethylene glycol monobutyl ether; 8g
・ Glycerin; 3g
・ Surfactant (Surfinol 440, manufactured by Air Products); 0.5 g
・ Ion exchange water; 64.6 g
-Aqueous dispersion of acrylic-urethane polymer (B) obtained in the above "Binder production example" (non-volatile content: 25% by mass); 2.4 g

PB15: 3 in Tables 3 and 4 is FASTOGEN Blue TGR [DIC Corporation C.I. I. Pigment Blue 15: 3], TPG represents tripropylene glycol, and DEG represents diethylene glycol.

Example 13
(Method for producing red aqueous pigment dispersion)
(Process 1)
Pigment FASTOGEN Super Magenta RY (manufactured by DIC Corporation) C.I. I. Pigment Red 122) 5000 parts by mass, a pigment dispersant composed of a tripropylene glycol solution of the acrylic-urethane polymer (P-1) obtained in Example 1 above, 5000 parts by mass, and a 34% by mass aqueous potassium hydroxide solution 242.6 parts by mass. The portion was charged into a planetary mixer PLM-V-50V (manufactured by Inoue Seisakusho Co., Ltd.) in a container 50L, and the jacket was heated. After the temperature in the kettle reached 40 ° C., kneading was performed for 2 hours to obtain a kneaded product.

(Process 2)
To the kneaded product, a total amount of 13300 parts by mass of ion-exchanged water heated to 40 ° C. was added over 2 hours to obtain an aqueous pigment composition having a pigment concentration of 21.2% by mass.
While adding 1500 parts by mass of tripropylene glycol and 8258 parts by mass of ion-exchanged water little by little to the aqueous pigment composition obtained by the above method, the mixture was stirred with a dispersion stirrer to obtain a red aqueous dispersion. The pigment concentration in this aqueous dispersion was 15.0% by mass.
Next, the aqueous dispersion was passed through a continuous centrifuge (H-600S, 2 L capacity, manufactured by Kokusan Co., Ltd.), centrifuged at a centrifugal force of 18900 G and a residence time of 10 minutes, and then a filter having an effective pore size of 0.5 μm. A red aqueous pigment dispersion was obtained by performing a filtration treatment according to 1. The pigment concentration of this aqueous pigment dispersion was 14.0% by mass.

(Method for producing water-based ink for inkjet recording)
The red aqueous pigment dispersion obtained above, 2-pyrrolidinone, triethylene glycol monobutyl ether, glycerin, surfactant (Surfinol 440, manufactured by Air Products) and ion-exchanged water are mixed in the following composition. Thus, a water-based ink for inkjet recording having a pigment concentration of 2% by mass and a solid content of the resin derived from the pigment dispersant of 0.6% by mass was prepared.
-Red aqueous pigment dispersion (pigment concentration: 14.0% by mass); 14.0 g
・ 2-Pyrrolidinone; 8g
・ Triethylene glycol monobutyl ether; 8g
・ Glycerin; 3g
・ Surfactant (Surfinol 440, manufactured by Air Products); 0.5 g
・ Ion exchange water; 66.5 g

[Examples 14 to 18 and Comparative Examples 10 to 13]
(Method for producing red aqueous pigment dispersion)
An aqueous pigment dispersion and an aqueous ink for inkjet recording were prepared in the same manner as in Example 1 except that the blending and blending ratios described in Tables 5 to 8 were changed.

[Comparative Example 14]
FASTOGEN Super Magenta RY (manufactured by DIC Corporation) C.I. I. An aqueous pigment dispersion and an inkjet recording water-based ink were prepared in the same manner as in Comparative Example 9, except that the pigment was changed to Pigment Red 122).

PR122 in Tables 5 and 6 is FASTOGEN Super Magenta RY (manufactured by DIC Corporation) C.I. I. Pigment Red 122), TPG represents tripropylene glycol, and DEG represents diethylene glycol.

Example 19
(Method for producing yellow aqueous pigment dispersion)
(Process 1)
Pigment Fast Yellow 7413 (CI Pigment Yellow 74, Sanyo Dye Co., Ltd.) 5000 parts by mass, a pigment dispersant containing a tripropylene glycol solution of the acrylic-urethane polymer (P-1) obtained in Example 1 above. 5000 parts by mass and 242.6 parts by mass of a 34% by mass potassium hydroxide aqueous solution were charged into a planetary mixer PLM-V-50V (manufactured by Inoue Seisakusho Co., Ltd.) in a container 50 L, and the jacket was heated. After the temperature in the kettle reached 40 ° C., kneading was performed for 2 hours to obtain a kneaded product.

(Process 2)
To the kneaded product, a total amount of 13300 parts by mass of ion-exchanged water heated to 40 ° C. was added over 2 hours to obtain an aqueous pigment composition having a pigment concentration of 21.2% by mass.
While adding 1500 parts by mass of tripropylene glycol and 8258 parts by mass of ion-exchanged water little by little to the aqueous pigment composition obtained by the above method, the mixture was stirred with a dispersion stirrer to obtain a yellow aqueous dispersion. The pigment concentration in this aqueous dispersion was 15.0% by mass.
Next, the aqueous dispersion was passed through a continuous centrifuge (H-600S, 2 L capacity, manufactured by Kokusan Co., Ltd.), centrifuged at a centrifugal force of 18900 G and a residence time of 10 minutes, and then a filter having an effective pore size of 0.5 μm. A yellow aqueous pigment dispersion was obtained by performing a filtration treatment according to 1. The pigment concentration of this aqueous pigment dispersion was 13.8% by mass.

(Method for producing water-based ink for inkjet recording)
The yellow aqueous pigment dispersion obtained above, 2-pyrrolidinone shown below, triethylene glycol monobutyl ether, glycerin, surfactant (Surfinol 440, manufactured by Air Products) and ion-exchanged water are combined as follows: Were mixed to prepare a water-based ink for inkjet recording having a pigment concentration of 2% by mass and a resin concentration containing a dispersant of 0.6% by mass.
Yellow aqueous pigment dispersion (pigment concentration: 13.8% by mass); 14.5 g
・ 2-Pyrrolidinone; 8g
・ Triethylene glycol monobutyl ether; 8g
・ Glycerin; 3g
・ Surfactant (Surfinol 440, manufactured by Air Products); 0.5 g
・ Ion exchange water; 66.0 g

[Examples 20 to 24 and Comparative Examples 15 to 18]
(Method for producing yellow aqueous pigment dispersion)
An aqueous pigment dispersion was obtained in the same manner as in Example 1 except that the blending ratios described in Tables 7 and 8 were changed to toluene or glycerin. In addition, a water-based ink for inkjet recording was prepared in the same manner as in Example 1.

[Comparative Example 19]
An aqueous pigment dispersion was obtained in the same manner as in Comparative Example 9 except that the pigment was changed to Fast Yellow 7413 (CI Pigment Yellow 74 Sanyo Dye Co., Ltd.). In addition, a water-based ink for inkjet recording was prepared in the same manner as in Comparative Example 9.

In Tables 7 and 8, PY74 represents Fast Yellow 7413 (CI Pigment Yellow 74, manufactured by Sanyo Pigment Co., Ltd.), TPG represents tripropylene glycol, and DEG represents diethylene glycol.

Example 25
(Method for producing black aqueous pigment dispersion)
(Process 1)
5000 parts by mass of a pigment dispersant comprising 5000 parts by mass of carbon black “# 960” manufactured by Mitsubishi Chemical Corporation and a tripropylene glycol solution of the acrylic-urethane polymer (P-1) obtained in Example 1 above, 34% by mass 242.6 parts by mass of an aqueous potassium hydroxide solution was charged into a planetary mixer PLM-V-50V (manufactured by Inoue Seisakusho Co., Ltd.) in a container 50L, and the jacket was heated. After the temperature in the kettle reached 40 ° C., kneading was performed for 2 hours to obtain a kneaded product.

(Process 2)
To the kneaded product, a total amount of 13300 parts by mass of ion-exchanged water heated to 40 ° C. was added over 2 hours to obtain an aqueous pigment composition having a pigment concentration of 21.2% by mass.
While adding 1500 parts by mass of tripropylene glycol and 8258 parts by mass of ion-exchanged water little by little to the aqueous pigment composition obtained by the above method, the mixture was stirred with a dispersion stirrer to obtain a black aqueous dispersion. The pigment concentration in this aqueous dispersion was 15.0% by mass.
Next, the aqueous dispersion was passed through a continuous centrifuge (H-600S, 2 L capacity, manufactured by Kokusan Co., Ltd.), centrifuged at a centrifugal force of 18900 G and a residence time of 10 minutes, and then a filter having an effective pore size of 0.5 μm. A black water-based pigment dispersion was obtained by performing a filtration treatment with the above. The pigment concentration of this aqueous pigment dispersion was 14.7% by mass.

(Method for producing water-based ink for inkjet recording)
The black aqueous pigment dispersion obtained above, 2-pyrrolidinone, triethylene glycol monobutyl ether, glycerin, surfactant (Surfinol 440, manufactured by Air Products) and ion-exchanged water are mixed in the following composition. As a result, a water-based ink for inkjet recording having a pigment concentration of 2% by mass and a resin concentration containing a dispersant of 0.6% by mass was prepared.
Black aqueous pigment dispersion (pigment concentration 14.7% by mass); 14.5 g
・ 2-Pyrrolidinone; 8g
・ Triethylene glycol monobutyl ether; 8g
・ Glycerin; 3g
・ Surfactant (Surfinol 440, manufactured by Air Products); 0.5 g
・ Ion exchange water; 66.0 g

[Examples 26 to 30 and Comparative Examples 20 to 23]
(Method for producing black aqueous pigment dispersion)
Aqueous pigment dispersion water-based ink for inkjet recording was prepared in the same manner as in Example 1 except that the blending ratios described in Tables 9 and 10 were changed.

[Comparative Example 32]
An aqueous pigment dispersion was obtained in the same manner as in Comparative Example 9, except that the pigment was changed to carbon black “# 960” manufactured by Mitsubishi Chemical Corporation. In addition, a water-based ink for inkjet recording was prepared in the same manner as in Comparative Example 9.

In Tables 9 and 10, # 960 represents carbon black “# 960” manufactured by Mitsubishi Chemical Corporation, TPG represents tripropylene glycol, and DEG represents diethylene glycol.

[Measurement of weight average molecular weight]
The weight average molecular weight of the acrylic-urethane polymer (P) was measured by gel permeation chromatograph (GPC method). Specifically, acrylic-urethane polymer (P) was coated on a glass plate with a 3 mil applicator and dried at room temperature for 1 hour to prepare a semi-dry coating film. The obtained coating film was peeled off from the glass plate, and 0.4 g was dissolved in 100 g of tetrahydrofuran to obtain a measurement sample.

Tetrahydrofuran was used as the eluent and sample solution, and the weight average molecular weight was measured using an RI detector with a flow rate of 1 mL / min, a sample injection amount of 500 μL, and a sample concentration of 0.4 mass%.
Measuring device: High-speed GPC device (“HLC-8220GPC” manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series.

"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 “TSKgel G2000” (7.8 mm ID × 30 cm) × 1 detector: RI (differential refractometer)
Column temperature: 40 ° C
Standard sample: A calibration curve was prepared using the following standard polystyrene.
(Standard polystyrene)
"TSKgel standard polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel standard polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel standard polystyrene F-550" manufactured by Tosoh Corporation

(Property value evaluation method)
[Measurement method of average particle diameter]
The particle size was measured using Nanotrac UPA-150EX (Nikkiso Co., Ltd.). Specifically, in an environment of 25 ° C., about 4 mL of the aqueous pigment dispersion is put in a measurement cell, and the volume average particle diameter (MV) is set to 3 by detecting scattered light of laser light with Nanotrac UPA-150EX. The average value (unit: nm) was calculated by measuring the number of times.

[Method of measuring viscosity]
Using a Viscometer TV-20 (manufactured by Toki Sangyo Co., Ltd.), the measured value of the water-based ink for inkjet recording at a temperature of 25 ° C. was used.

[Evaluation method of ink ejection stability]
A diagnostic page was printed on the Photomart D5360 (manufactured by Hewlett-Packard) filled with a black ink cartridge with the water-based ink for ink-jet recording, and the state of the nozzle was confirmed. After continuously printing 20 pages of solid print with a print density setting of 100% in an area of 18 cm × 25 cm per page, a diagnostic page was printed again to check the state of the nozzles. The change in the state of the nozzles before and after continuous solid printing was evaluated as the ink ejection property. The evaluation criteria are described below.

[Criteria]
A: No change in the state of the nozzle and no abnormal discharge B: Some ink adhesion to the nozzle was confirmed, but no abnormal ink discharge direction C: Solid Abnormal ink ejection direction or non-ejection of ink after printing 20 pages continuously D: Abnormal ink ejection direction or non-ejection of ink occurred during printing. What could not be printed

[Evaluation method of scratch resistance]
Using a commercially available thermal jet ink jet printer (Photomart D5360; manufactured by Hewlett Packard) on the printing surface of photographic printing paper (glossy) [HP Advanced Photo Paper manufactured by Hewlett Packard], the above-described water-based ink for inkjet recording is used. The black ink cartridge was filled and solid printing was performed with a print density setting of 100%.
After the printed matter was dried at room temperature for 10 minutes, the printed surface was rubbed with a nail, and the rubbing condition of the printed surface was visually evaluated. The evaluation criteria are described below.
[Criteria]
A: The printed surface was not damaged at all, and the printing material was not peeled off.
B: Although some scratches were generated on the printing surface, no peeling of the coloring material was observed.
C: Remarkable scratches were generated on the printing surface, and peeling of the coloring material was observed.
D: Extensive scratches were generated over a wide area on the printed surface, and coloring material was peeled off.

Abbreviations in Tables 11 to 18 are as shown below.
-PB: 15: 3: FASTOGEN Blue TGR [C. I. Pigment Blue 15: 3]
PR122: FASTOGEN Super Magenta RY (manufactured by DIC Corporation) C.I. I. Pigment Red 122)
-PY74: Fast Yellow 7413 (CI Pigment Yellow 74 Sanyo Dye Co., Ltd.)
# 960: Carbon black "# 960" manufactured by Mitsubishi Chemical Corporation
・ TPG: Tripropylene glycol ・ DEG: Diethylene glycol

From the above evaluation results, the water-based ink for inkjet recording of Examples using the pigment dispersant of the present invention has a small dispersed particle size and excellent pigment dispersibility. Furthermore, it was confirmed that the ejection stability and scratch resistance were also excellent. On the other hand, it was confirmed that the water-based ink for inkjet recording of Comparative Example had a problem because the dispersed particle size was large or the ejection stability and the scratch resistance were not compatible.

Claims (8)

A pigment dispersant containing an acrylic-urethane polymer (P) having a structure derived from the vinyl polymer (V) in the side chain and having an acid value of 20 to 80, wherein the acrylic-urethane polymer (P) is an ether or ester And a pigment dispersant having one or more structures selected from the group consisting of carbonates. The acrylic-urethane polymer (P) is one or more selected from the group consisting of a vinyl polymer (V) having two hydroxyl groups at one end and a polyether polyol, polyester polyol, polyester ether polyol and polycarbonate polyol. The pigment dispersant according to claim 1, which is a reaction product of a polyol (A) containing a polyol (a2) and a polyol (a3) having a hydrophilic group, and a polyisocyanate (B). The vinyl polymer (V) having two hydroxyl groups at one end is contained in the range of 1% by mass to 70% by mass with respect to the total mass of raw materials used for the production of the acrylic-urethane polymer (P). The pigment dispersant according to claim 2. The pigment dispersant according to claim 2, wherein the vinyl polymer (V) having two hydroxyl groups at one end has a number average molecular weight of 500 to 10,000. The pigment dispersant according to any one of claims 2 to 4, wherein the acrylic-urethane polymer (P) has a weight average molecular weight in the range of 5000 to 150,000. The pigment dispersant, pigment, basic compound, water, and organic solvent (S octanol / water partition coefficient) according to any one of claims 1 to 5 in the range of -1.75 to 2.00 A water-based pigment dispersion characterized by comprising A vinyl polymer (V) having two hydroxyl groups at one end, at least one polyol (a2) selected from the group consisting of polyether polyol, polyester polyol, polyester ether polyol and polycarbonate polyol, and a hydrophilic group. It has a structure derived from the vinyl polymer (V) in the side chain, characterized by reacting the polyol (A) containing the polyol (a3) with the polyisocyanate (B), and having an acid value of A method for producing a pigment dispersant containing an acrylic-urethane polymer (P) which is a reaction product of 20 to 80 mg KOH / g. The pigment dispersant, pigment, basic compound and organic solvent (S) having a log Kow (octanol / water partition coefficient) of -1.75 to 2.00 according to any one of claims 1 to 5. A method for producing an aqueous pigment dispersion, comprising a step 1 for kneading and a step 2 for dispersing the kneaded product obtained in the step 1 in water.