JP2016199653A - Pigment composition and production method of the same, and inkjet ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous pigment composition that is finely dispersed, has high storage stability, and is suitably used for an inkjet ink or the like and a production method of the composition.SOLUTION: A production method of a pigment composition is provided, which includes: a step (a) of adding a water-soluble inorganic salt, a water-soluble organic solvent and a dispersant to a pigment and grinding and kneading the materials to finely pulverize the pigment; a step (b) of feeding water after the step (a) to obtain a suspension; a step (c) of removing the water-soluble inorganic salt after the step (b) and removing the water-soluble organic solvent to satisfy the following condition (A); and a step (e) of adding water and a basic compound after the step (c). The water-soluble organic solvent satisfies conditions (i) to (iv). (A) The water-soluble organic solvent remains in a range from 0.005 to 0.5 parts by mass with respect to 100 parts by mass of the pigment included in the pigment composition.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pigment composition containing a micronized pigment and a method for producing the same. Moreover, it is related with the inkjet ink containing the said pigment composition.

  From the viewpoint of pollution prevention and occupational health, the industry that uses colorants such as paints and inks is strongly water-based.

  In order to disperse a pigment used for an aqueous colorant in an aqueous medium, a method of dispersing a powder pigment using a surfactant or a water-soluble resin is generally used, and it is widely practiced at present. However, a paint containing a pigment dispersed using a surfactant has a problem that the resulting coating film has extremely poor water resistance and can be used only for limited applications. Further, it is generally more difficult to disperse the pigment in the aqueous medium containing the water-soluble resin than when the pigment is dispersed in the organic solvent medium, the pigment is finely dispersed at a high level, and It is difficult to keep that state stable.

  On the other hand, when a pigment is simply dispersed using a water-soluble resin, the bond between the pigment and the resin is only due to a weak bond called adsorption, even if it is finely dispersed immediately after production. There is a problem that the storage stability is not good because the pigment aggregates with time.

  As a method of obtaining an easily dispersible pigment, an acid is added to an aqueous dispersion of a pigment dispersed in a resin having a carboxyl group neutralized with a base to make the resin hydrophobic by adding an acid. A so-called acid precipitation method for fixing to a pigment is known.

  For example, a technique is known in which rosin is used to adhere to a pigment by an acid precipitation method to obtain a powder pigment with good dispersibility. However, rosin cannot be a film-forming resin due to its low molecular weight, and is extremely inferior in weather resistance, so the amount of rosin used cannot be increased, and the amount used is about 10% by mass or less. The current situation is that we have to limit it. Therefore, rosin is currently used in powder pigments as a pigment treatment agent. When used in an aqueous pigment dispersion as in the present invention, rosin alone cannot provide a stable aqueous pigment dispersion. Also, there is a problem that the performance of the obtained coating film is low.

  In order to solve this problem, a method of obtaining a powder or solid pigment by performing acid precipitation using a limited resin such as a relatively high molecular weight acrylic resin is disclosed. (Patent Documents 1 and 2)

  However, in any of these methods, since the powder is formed or solidified after the acid precipitation, the pigment is agglomerated not a little in the process, and is kneaded again when used in water-based paints and water-based inks. There is a problem that a time-consuming process is necessary. Moreover, although the powder or solid pigment obtained by these methods is more easily dispersible than the untreated powder pigment, it is a powder once solidified or solidified. There is also a problem that considerable labor is required to finely disperse to such an extent that the coloring power is exhibited.

  Also disclosed is a method for treating a polymer dispersing resin with a pigment during solvent salt milling, which is a pigmentation step. (Patent Document 3)

  However, this method has a problem in that an effective resin treatment is not applied to the pigment, so that a dispersion step using a sand mill is inevitably required to obtain ink.

JP-A-50-122528 Japanese Patent Publication No. 61-11979 Japanese Patent No. 3168210

  The problems to be solved by the present invention are finely dispersed and have good storage stability, which cannot be achieved by the above-described prior art, and include paint, paper coating, textile printing, writing instrument ink, printing ink, inkjet ink, cosmetics, An object of the present invention is to provide an aqueous pigment composition suitably used for electrostatic toners and the like and a method for producing the same.

As a result of extensive studies by the present inventors in order to solve the above-mentioned problems, surprisingly, in the following embodiment, which is produced using a water-soluble organic solvent satisfying all of (i) to (iv), The present inventors have found that the problem can be solved and have completed the present invention.
[1] A step (a) in which at least a water-soluble inorganic salt, a water-soluble organic solvent and a dispersant are added to the pigment, and the pigment is refined by milling and kneading;
After step (a), water is added to obtain a suspension (b);
(C) after the step (b), removing the water-soluble inorganic salt and removing the water-soluble organic solvent so as to satisfy the following (A);
After the step (c), the method includes a step (e) of adding water and a basic compound,
The water-soluble organic solvent is a method for producing a pigment composition that satisfies the following (i) to (iv).
(A) The water-soluble organic solvent remains in a range of 0.005 to 0.5 parts by mass per 100 parts by mass of the pigment contained in the pigment composition.
(I) The molecular weight is 130-350.
(Ii) It has a total of 2 or more functional groups (F) comprising a hydroxyl group and / or an ester group.
(Iii) The viscosity at 60 ° C. is 2 to 140 mPa · s.
(Iv) Does not contain an ether bond.
[2] The method for producing a pigment composition according to [1], further comprising a step (d) of removing water between the step (c) and the step (e).
[3] The water-soluble organic solvent is 2-ethyl-1,3-hexanediol, 2,4-diethyl-1,5-pentanediol, monoacetin, diacetin, triacetin, tripropionine, tributyrin and 2-butyl-2- The method for producing a pigment composition according to [1] or [2], which is at least one selected from the group consisting of ethyl-1,3-propanediol.
[4] The pigment composition according to [1] to [3], wherein the pigment is at least one selected from the group consisting of dyed lake pigments, azo pigments, phthalocyanine pigments, and condensed polycyclic pigments. Manufacturing method.
[5] A pigment composition comprising a finely divided pigment having an average primary particle size in the range of 5 to 1,000 nm and a water-soluble organic solvent,
A pigment composition comprising 0.005 to 0.5 parts by mass of a water-soluble organic solvent satisfying the following (i) to (iv) per 100 parts by mass of the pigment contained in the pigment composition.
(I) The molecular weight is 130-350.
(Ii) It has a total of 2 or more functional groups (F) comprising a hydroxyl group and / or an ester group.
(Iii) The viscosity at 60 ° C. is 2 to 140 mPa · s.
(Iv) Does not contain an ether bond.
[6] An inkjet ink comprising the pigment composition according to [5].

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in the dispersibility of the refined | miniaturized pigment, and there exists the outstanding effect that the refined | miniaturized pigment composition and its manufacturing method with high production efficiency, and the inkjet pigment composition can be provided.

The flowchart for demonstrating the manufacturing process of the pigment composition which concerns on embodiment.

  Hereinafter, an example of an embodiment to which the present invention is applied will be described. Needless to say, other embodiments are also included in the scope of the present invention as long as they meet the spirit of the present invention. In the present specification, the description “any number A to any number B” includes the number A as a lower limit and the number B as an upper limit in the range.

  The pigment composition of the present invention is obtained by performing at least the following steps (a) to (e), (a) to (c) and (e) shown in FIG.

<Step (a)> In step (a), at least a water-soluble inorganic salt, a water-soluble organic solvent and a dispersant are added to the pigment, and the pigment is refined by grinding and kneading. The method for refining the pigment by milling and kneading is not particularly limited, and any method can be applied, but a milling and kneading process by so-called salt milling is suitable. The average primary particle diameter of the pigment to be refined may vary depending on the application, but is usually 5 to 1,000 nm. As the pigment used here, an untreated crude pigment is usually used, but a pigment that has undergone some processing step may be used. The pigment used may be a single type or a plurality of types.

  The milling and kneading method includes mixing a mixture containing at least a pigment, a water-soluble inorganic salt, and a water-soluble organic solvent into a kneader, a two-roll mill, a three-roll mill, a ball mill, an attritor, a horizontal sand mill, a vertical sand mill, and / or an annula type. It can be performed using a kneader such as a bead mill. The processing conditions and the like may be adjusted as appropriate according to the type of pigment, the required degree of refinement, and the like. Heating is preferably performed when mechanically kneading. The water-soluble inorganic salt serves as a crushing aid, and crushes the pigment using the high hardness of the water-soluble inorganic salt during salt milling. By optimizing the conditions for the salt milling treatment, a pigment having a very fine primary particle diameter, a narrow distribution width, and a sharp particle size distribution can be obtained.

The pigment is not particularly limited as long as it does not depart from the spirit of the present invention, and organic pigments and inorganic pigments can be applied. Examples of preferable pigments include at least one organic pigment selected from dyed lake pigments, azo pigments, phthalocyanine pigments, and condensed polycyclic pigments. As the azo pigment, either a soluble azo pigment or an insoluble azo pigment may be used. Preferable specific examples of the pigment include the following pigments.
Pigment yellow (hereinafter abbreviated as PY) 18, PY100, PY104, pigment orange (hereinafter abbreviated as PO) 39, pigment red (hereinafter abbreviated as PR) PR81, PR83, PR90, PR169, PR172, PR173, PR174, PR193, Pigment Violet (hereinafter abbreviated as PV) 1, PV2, PV3, PV4, PV12, PV27, PV39, Pigment Blue (hereinafter abbreviated as PB) 1, PB2, PB14, PB62, Pigment Green (hereinafter abbreviated as PG) PG1, PG2, PG3, PG4, PG45, and the like.
As the azo pigment, soluble azo pigments such as PR53, PR50, PR49, PR57: 1, PR48: 1, PR52: 1, PR1, PR3, PO5, PR21, PR114, PR5, PR146, PR170, PO38, PR187, PY1, Examples include insoluble azo pigments such as PY3, PY167, PY154, PO36, PY12, PY13, and PY14, and condensed azo pigments such as PR144, PR166, PR214, PR242, PY93, PY94, and PY95.
Examples of the phthalocyanine pigment include PB16, PB15: 1, PB15: 2, PB15: 3, PB15: 4, PB15: 5, PB15: 6, PG7, PG36, PG58, aluminum phthalocyanine, and the like.
Examples of the condensed polycyclic pigment include PY24, PY108, PO51, PR168, PR177, PB60, PY38, PR88, PO43, PR194, PR178, PR179, PY138, PV23, PV19, PR122, PY109, PY110, PY150, PY139, PR254. , PR255, PR272, PO71, dibromodiketopyrrolopyrrole and the like.

The water-soluble organic solvent functions to wet the pigment and the water-soluble inorganic salt, and needs to be dissolved (mixed) in water and does not substantially dissolve the water-soluble inorganic salt to be used. Furthermore, the water-soluble organic solvent of the present invention satisfies the following (i) to (iv). That is,
(I) molecular weight 130-350,
(Ii) having a total of 2 or more functional groups (F) comprising a hydroxyl group (OH group) and / or an ester group (—COO— group), and (iii) a viscosity at 60 ° C. of 2 to 140 mPa · s. Yes,
(Iv) does not contain an ether bond,
It satisfies all the conditions. The water-soluble organic solvent of the present invention may be used alone or in combination. A water-soluble organic solvent satisfying these (i) to (iv) (hereinafter also referred to as the water-soluble organic solvent of the present invention) is suitable as a solvent for milling and kneading. In addition, the use of a solvent other than the water-soluble organic solvent of the present invention (including a water-soluble organic solvent not satisfying any one or more of the above (i) to (iv)) is within a range not departing from the gist of the present invention. It is not excluded. However, from the viewpoint of effectively increasing the dispersibility of the fine pigment, it is preferable to substantially use the water-soluble organic solvent of the present invention. Hereinafter, the water-soluble organic solvent of the present invention will be described.

  (Ii) having a total of two or more functional groups (F) comprising hydroxyl groups and / or ester groups: a) a solvent containing two or more hydroxyl groups and no ester groups; b) two ester groups The above includes a solvent that does not include a hydroxyl group, and c) includes three modes including both a hydroxyl group and an ester group, and the sum of the two is 2 or more. The viscosity of (iii) is a viscosity when a water-soluble organic solvent is measured alone at a temperature of 60 ° C. The viscosity of the water-soluble organic solvent in the present specification is a value measured using a conical plate type rotational viscometer (viscosity measuring device manufactured by Toki Sangyo Co., Ltd .: TVE-20L) in accordance with JIS Z 8803. Further, as specified in (iv), the water-soluble organic solvent does not contain an ether bond in its molecule.

  By using a water-soluble organic solvent that satisfies all of (i) to (iv), the dispersibility of the refined pigment can be improved. The reason is not speculative, but it is considered that the water-soluble organic solvent of the present invention gives good results in the interaction with the pigment. In addition, the water-soluble organic solvent of the present invention remains in a specific range with respect to the pigment, so that it is considered that there is an effect of suppressing the aggregation of the refined pigment.

  The water-soluble organic solvent used in the step (a) is not particularly limited as long as it satisfies all of the above (i) to (iv). As a preferred example, 2-ethyl-1,3-hexanediol (16. 6 mPa · s), 2,4-diethyl-1,5-pentanediol (67.2 mPa · s), monoacetin (13.7 mPa · s), diacetin (8.2 mPa · s), triacetin (4.1 mPa · s) ), Tripropionine (2.7 mPa · s), tributyrin (3.3 mPa · s) and 2-butyl-2-ethyl-1,3-propanediol (43.7 mPa · s). .

  The amount added of the water-soluble organic solvent of the present invention is not particularly limited, but it is preferably 5 to 1,000 parts by mass, more preferably 50 to 500 parts by mass with respect to 100 parts by mass of the pigment. The water-soluble organic solvent may be used alone or in combination.

  The water-soluble inorganic salt used in the step (a) is not limited as long as it is an inorganic salt exhibiting water-solubility as its name does not depart from the gist of the present invention. Preferred examples include sodium chloride, barium chloride, potassium chloride, sodium sulfate and the like. It is preferable to use sodium chloride (salt) from the viewpoint of price. The water-soluble inorganic salt is preferably used in an amount of 50 to 2,000 parts by mass, more preferably 300 to 1,000 parts by mass with respect to 100 parts by mass of the pigment, from both the treatment efficiency and the production efficiency.

  If the dispersing agent used at a process (a) is resin which has the acid value based on a carboxyl group in the range of 30-400 mgKOH / g, it can be especially used without a restriction | limiting. Examples of such resins include vinyl copolymers, polyester resins, polyurethane resins, epoxy resins, and rosin-modified resins. Among these, vinyl copolymers, polyester resins, and polyurethane resins are preferable from the viewpoints of easy introduction of carboxyl groups and toughness of the coating.

Examples of the vinyl copolymer used in the production method of the present invention include (meth) acrylic acid ester resin, (meth) acrylic acid ester-styrene copolymer resin, and styrene- (anhydrous) maleic acid copolymer resin. And fluorine-containing vinyl copolymer resins. Moreover, as a polyester resin used in the manufacturing method of this invention, a saturated polyester resin, an unsaturated polyester resin, an alkyd resin etc. are mentioned, for example. These resins are required to contain a carboxyl group as a hydrophilic group for imparting appropriate water solubility or water dispersibility.

The vinyl copolymer having a carboxyl group can be easily produced by a method of copolymerizing a polymerizable monomer composition containing a polymerizable monomer having a carboxyl group. Examples of the polymerizable monomer having a carboxyl group include acrylic acid, methacrylic acid, crotonic acid, fumaric acid, itaconic acid, (anhydrous) maleic acid, monoalkyl maleates such as monobutyl maleate, and itacones such as monobutyl itaconic acid. Examples include acid monoalkyls.

Examples of the polymerizable vinyl monomer other than the polymerizable vinyl monomer having a carboxyl group contained in the polymerizable monomer composition include aromatic vinyl monomers such as styrene, vinyl toluene, and α-methylstyrene; methyl (meth) acrylate. , Ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, isoamyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isodecyl (meth) acrylate, lauryl (Meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, butoxymethyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, benzyl (meth) acrylate (Meth) acrylic acid esters such as cetyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate; vinyl esters such as vinyl acetate, vinyl benzoate, vinyl versatic acid, vinyl propionate; Polymerizable nitriles such as (meth) acrylonitrile; vinyl monomers having a fluorine atom such as vinyl fluoride, vinylidene fluoride, tetrafluoroethylene, hexafluoropropylene or chlorotrifluoroethylene; diethylaminoethyl (meth) acrylate, dimethylaminoethyl Monomers having a tertiary amino group such as (meth) acrylate, N-vinylimidazole, N-vinylcarbazole; 2- (2
'-Hydroxy-5-methacryloyloxyethylphenyl) -2H-benzotriazole, 2-hydroxy-4- (2-methacryloyloxyethoxy) benzophenone, 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate Monomers having ultraviolet absorbing property or antioxidant property; N-vinylpyrrolidone, glycidyl (meth) acrylate, 1,3-dioxolan-2-one-4-ylmethyl (meth) acrylate, 1,3-dioxolan-2-one Monomers having functional groups such as N-alkoxymethyl (meth) acrylamides such as -4-ylmethyl vinyl ether, diacetone acrylamide, N-methylol acrylamide, N-butoxymethyl (meth) acrylamide; γ-methacryloxypropyltri Metoki Monomers having hydrolyzable alkoxysilane groups such as silane and vinyltrimethoxysilane; Monomers having phosphate groups such as 2-phosphooxyethyl (meth) acrylate and 4-phosphooxybutyl (meth) acrylate; And macromonomers having one polymerizable unsaturated group.

As the polymerization method for the polymerizable vinyl monomer composition, various known polymerization methods such as suspension polymerization, emulsion polymerization, bulk polymerization, and solution polymerization can be used. As the polymerization initiator, known peroxides and azo compounds can be used.

The polyester resin having a carboxyl group used in the present invention undergoes a dehydration condensation reaction between a compound having a carboxyl group and a compound having a hydroxyl group by a known method such as a melting method or a solvent method so that the carboxyl group remains. Can be manufactured.

The polyester resin is obtained by appropriately dehydrating and condensing a compound having a carboxyl group such as a monobasic acid, a dibasic acid, or a polybasic acid and a compound having a hydroxyl group such as a diol or a polyol, and Those using oils or fats or fatty acids are alkyd resins.

The carboxyl group which the polyester resin used with the manufacturing method of this invention has is an unreacted carboxyl group mainly derived from the dibasic acid or polybasic acid which comprises a polyester resin.

Examples of the dibasic acid or polybasic acid include adipic acid, (anhydrous) succinic acid, sebacic acid, dimer acid, (anhydrous) maleic acid, (anhydrous) phthalic acid, isophthalic acid, terephthalic acid, tetrahydro (anhydrous) phthalate Examples thereof include acid, hexahydro (anhydride) phthalic acid, hexahydroterephthalic acid, 2,6-naphthalenedicarboxylic acid, (anhydrous) trimellitic acid, and (anhydrous) pyromellitic acid.

Examples of compounds having a carboxyl group that can be used in addition to dibasic acids or polybasic acids include lower alkyl esters of acids such as dimethyl terephthalate; benzoic acid, p-tertiarybutylbenzoic acid, rosin, and hydrogenated rosin. Monobasic acids such as: fatty acids and oils and fats; macromonomers having 1 or 2 carboxyl groups at the molecular terminals; 5-sodium sulfoisophthalic acid and dimethyl esters thereof.

Examples of the compound having a hydroxyl group include ethylene glycol, neopentyl glycol, propylene glycol, diethylene glycol, dipropylene glycol, 2-methyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1 , 4-butanediol, 1,3-propanediol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, 1,5-pentanediol, alkylene oxide adduct of bisphenol A, hydrogenated bisphenol A, hydrogenated Alkylene oxide adducts of bisphenol A, diols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol; glycerin, trimethylolpropane, trimethylolethane, diglycerin, pentaerythridine Polyols such as lithol and trishydroxyethyl isocyanurate; monoglycidyl compounds such as “Cardura E-10” (a glycidyl ester of a synthetic fatty acid manufactured by Shell Chemical Industry Co., Ltd.), a macromonomer having two hydroxyl groups at one molecular end And the like.

Moreover, when synthesizing a polyester resin, a fatty acid or oil having a hydroxyl group such as castor oil or 12-hydroxystearic acid; a carboxyl group such as dimethylolpropionic acid, p-hydroxybenzoic acid, or ε-caprolactone and a hydroxyl group. Compounds and the like can also be used.

Furthermore, a part of the dibasic acid can be replaced with a diisocyanate compound.

As the polyester resin having a carboxyl group used in the production method of the present invention, a modified polyester resin obtained by grafting a polymerizable monomer having a carboxyl group onto the polyester resin can also be used.

A polyurethane having a carboxyl group can be easily produced by using a compound having a carboxyl group and a hydroxyl group such as dimethylolpropionic acid as a segment having a hydroxyl group.

The polyurethane resin having a carboxyl group used in the production method of the present invention reacts with a polyol component containing a compound having a carboxyl group and a hydroxyl group such as dimethylolpropionic acid as a component for introducing a carboxyl group, and a polyisocyanate component. By making it, it can manufacture easily.

As the polyol component, in addition to the diol component listed in the polyester production method, a trifunctional or higher functional polyol compound may be used as necessary.

Polyisocyanate components include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, phenylene diisocyanate, 1,5-naphthalene diisocyanate, metaxylylene diisocyanate, isophorone In addition to diisocyanate compounds such as diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated 4,4′-diphenylmethane diisocyanate, hydrogenated metaxylylene diisocyanate, crude 4,4′-diphenylmethane diisocyanate, and polyisocyanate compounds such as polymethylene polyphenyl isocyanate Can also be used.

The polyurethane resin may be produced by a conventional method. For example, the addition reaction is preferably performed at room temperature or a temperature of about 40 to 100 ° C. in an inert organic solvent solution that does not react with an isocyanate group. At that time, a known catalyst such as dibutyltin dilaurate may be used.

In the reaction system for producing the polyurethane resin, known chain extenders such as diamine, polyamine, N-alkyl dialkanolamine such as N-methyldiethanolamine; dihydrazide compound can also be used.

Further, as the resin (A) having a carboxyl group used in the production method of the present invention, a vinyl copolymer having a hydroxyl group or a polyester resin, maleic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride Also, a resin having a carboxyl group obtained by a method of addition reaction of a polybasic anhydride such as trimellitic anhydride can be used.

The amount of the carboxyl group in the resin (A) having a carboxyl group used in the present invention is preferably in the range where the acid value is 30 to 400 mgKOH / g, and more preferably in the range of 150 to 350 mgKOH / g.

The resin (A) having a carboxyl group used in the production method of the present invention is more preferably one having a hydroxyl group in addition to the carboxyl group. The hydroxyl group bonded to the resin (A) can react with a curing agent to form a stronger film when used in baking paints, baking inks, printing agents, and the like.

A vinyl copolymer having a carboxyl group and a hydroxyl group can be easily produced by a method of copolymerizing a polymerizable monomer used in producing a vinyl copolymer having a carboxyl group with a polymerizable monomer having a hydroxyl group. can do.

Examples of the polymerizable monomer having a hydroxyl group include alkyl (meth) acrylate having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate; (Meth) acrylic monomers to which lactone compounds represented by “FM-2” and “Placcel FA-2” (manufactured by Daicel Chemical Industries, Ltd.) are added; polyethylene glycol mono (meth) acrylate monomers; polypropylene glycol mono (meta) ) Acrylate monomers; alkyl vinyl ethers having a hydroxyl group such as hydroxyethyl vinyl ether and hydroxybutyl vinyl ether.

The polyester resin having a carboxyl group and a hydroxyl group may be reacted so that the hydroxyl group remains in the dehydration condensation reaction of the polyester resin according to a known method. The remaining hydroxyl group is an unreacted group derived from a diol compound, a polyol compound or a carboxylic acid polyol compound.

The vinyl copolymer having a carboxyl group and the polyurethane resin used in the production method of the present invention preferably have a number average molecular weight in the range of 5,000 to 20,000.

Since the polyester resin used in the production method of the present invention is mostly branched, the mass average molecular weight is low even when the number average molecular weight is small, unlike the case of a linear vinyl copolymer or the like. Since it is large, it has sufficient toughness as a coating film. Accordingly, the polyester resin preferably has a number average molecular weight in the range of 1,000 to 20,000, and preferably has a mass average molecular weight in the range of 5,000 to 100,000.

The following describes a dispersant that is preferable as a pigment composition for inkjet ink. From the viewpoint of improving ink dispersibility and storage stability, it is preferable to use a copolymer (copolymer) containing the following monomer A, monomer B and monomer C in the copolymer composition as a dispersant. .
Monomer A: (meth) acrylate ester monomer having an alkyl group having 10 to 24 carbon atoms B: styrene, α-methylstyrene or benzyl (meth) acrylate monomer C: (meth) acrylic acid

Preferred specific examples of the monomer A include, for example, decyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, Examples include hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, and behenyl (meth) acrylate. In order to further improve the storage stability, it is particularly preferable to select lauryl (meth) acrylate, stearyl (meth) acrylate, or behenyl (meth) acrylate.

The monomer B is styrene, α-methylstyrene, or benzyl (meth) acrylate. In order to improve the storage stability to a higher degree, it is preferable to select styrene. A monomer having an aromatic group other than monomer B may be used in combination.

Although the monomer C is (meth) acrylic acid, a monomer having an acidic functional group other than (meth) acrylic acid may be used in combination. Examples of monomers having an acidic functional group that can be used in this case include maleic acid, maleic acid half ester, itaconic acid, itaconic acid half ester, fumaric acid, fumaric acid half ester, vinyl sulfonic acid, and vinyl phosphonic acid. Is mentioned.

Furthermore, the mass ratio of the monomer A and the monomer B is preferably monomer A / monomer B = 1/9 to 9/1, and monomer A / monomer B = More preferably, it is 1/4 to 4/1. The ratio of the total amount of monomers A, B and C in the total amount of the copolymer is preferably 70 to 100% by mass.

  The reason why the dispersant is preferable as a pigment composition for inkjet inks is that, in order to eliminate quick drying on a printing substrate and printing unevenness while securing moisture retention on inkjet head nozzles as inkjet inks, This is because a stable dispersion can be obtained even when (poly) alkylene glycol monoalkyl ether and alkanediol having 3 to 6 carbon atoms having a high permeability to the material and good wettability are contained. Since (poly) alkylene glycol monoalkyl ethers and alkanediols having 3 to 6 carbon atoms are relatively hydrophobic, there is a concern that the dispersant is easily dissolved and the dispersibility is lowered by desorbing the dispersant from the pigment. However, if the dispersant is a copolymer containing the monomers A, B, and C in the copolymer composition, it can form a very strong interaction with the pigment, so that the dispersibility can be maintained. Is possible.

The effects of the monomers A, B, and C will be described below. Since the alkyl group in the monomer A having 10 to 24 carbon atoms has a highly hydrophobic structure, it can increase the hydrophobicity of the dispersant and form a strong hydrophobic interaction with the pigment. become. In addition, the monomer B has a structure having an aromatic ring, can ensure the affinity due to the π-electron interaction with the pigment, and can further enhance the dispersibility. The reason why (meth) acrylic acid is used as the monomer C is to repel charges when ionized, as in the case of ordinary dispersants. It is considered that the dispersant adsorbed on the pigment has ionized (meth) acrylic acid, and in the aqueous solvent, charge repulsion occurs between the pigments, and the dispersibility is maintained. From these effects, the dispersant which is a copolymer containing monomers A, B, and C in the copolymer composition can exhibit particularly good dispersibility and storage stability in the inkjet ink.

In the step (a), an additive such as a pigment derivative may be further included. As the pigment derivative, a compound having an organic pigment as a basic skeleton and having introduced a substituent imparting acidity or a substituent imparting basicity into the molecule is suitable. By adding an organic pigment derivative, it is considered that the pigment is adsorbed by the pigment to be dispersed and imparts polarity, thereby giving a dispersion effect from the interaction with the dispersant and the resin. In addition, an effect contributing to pigment crystal stabilization and dispersion stabilization can be expected.
Specifically, as examples of commercially available products, EFKA-6745, 6750 (manufactured by EFKA Additive), BYK-Synergist 2100 (manufactured by Big Chemie Japan), Solsperse 5000, 12000, 22000 (manufactured by Lubrizol Japan), etc. Is mentioned.
In addition, a fiber derivative, a rubber derivative, and / or a protein derivative can be selected and used in accordance with the synthetic resin. In particular, epoxy resins and (meth) acrylic resins are preferably used as these synthetic resins.
The epoxy resin refers to an epoxide containing one or more epoxy groups in the molecule, and in the present invention, a soluble one that is not crosslinked with a curing agent is preferable. Epoxides include bisphenol-type, novolak-type, alkylphenol-type, resorcin-type, polyglycol-type, ester-type, glycidyl type such as N-glycidylamine, and cyclic aliphatic epoxides.
The (meth) acrylic resin is a copolymer of a simple substance or a mixture selected from monomers of acrylic acid, methacrylic acid and esters thereof, and these are further radically polymerizable such as styrene, vinyl acetate, maleic anhydride and the like. It may be a copolymer with a monomer.

  The amount of each of the water-soluble organic solvent, water-soluble inorganic salt, dispersant, etc. added to the pigment is not limited as long as the pigment can be refined, but the shear force that effectively grinds the pigment with the water-soluble inorganic salt. It is important for the miniaturization process to have a viscosity and hardness that can be given.

<Step (b)> After performing step (a), water is added thereto to obtain a suspension (FIG. 1). Preferably, after the completion of the step (a), the pigment dispersion is taken out from the grinding kneader, and water is added thereto to perform stirring to obtain a suspension. The amount of water to be added is not particularly limited as long as it is sufficient to obtain a suspension. You may heat as needed. For example, water having a mass of 10 to 10,000 times the mass of the step (a) is added and mixed and stirred. Although the mixing stirring conditions at this time are not specifically limited, For example, it can carry out at the temperature of 25-90 degreeC.

<Step (c)> After the treatment in step (b), the water-soluble inorganic salt is removed, and the water-soluble organic solvent satisfying the following (A) is removed (FIG. 1).
(A) A water-soluble organic solvent remains in the range of 0.005 to 0.5 parts by mass per 100 parts by mass of the pigment contained in the pigment composition.
The method of leaving the water-soluble organic solvent in the specific range can be easily adjusted by controlling the removal conditions (for example, washing conditions, drying conditions, filtration conditions). The treatment process is not limited as long as the above object can be achieved, but a method of removing the filtrate by filtration is simple.
The residual solvent per 100 parts by mass of pigment contained in the pigment composition is obtained by measuring the residual solvent of the water-soluble organic solvent of the present invention in the total solid content in the pigment composition, and calculated from the ratio of the pigment in the solid content. it can. Here, the ratio of the pigment in the solid content is defined as the ratio of the charged amount of the pigment to the total solid content in the finally obtained pigment composition. Actually, the pigment may be slightly lost in step (b) or the like, but the ratio of the pigment in the solid content in the present specification is as described above.

<Step (d)> After step (c), water is removed (FIG. 1). Although it will not be limited if it is the method of removing water, The method of performing a drying process can be mentioned as a suitable method. The drying conditions in the step (d) are, for example, a method of drying for 12 to 48 hours at 80 to 120 ° C. under normal pressure, and drying for 12 to 60 hours at 25 to 80 ° C. under reduced pressure. An example is a method of performing, and after freezing in a range of −60 to −5 ° C., a method of performing drying for about 12 to 60 hours in a range of 25 to 80 ° C. under reduced pressure. Although a drying process is not specifically limited, The method using a spray drying apparatus can be illustrated. A pulverization process may be performed simultaneously with the drying process or after the drying process.

  As the water used in the step (d), it is preferable to use ion-exchanged water (deionized water) instead of general water containing various ions.

<Step (e)> After step (d), water and a basic compound are added and mixed and stirred. (See FIG. 1) The mixing and stirring method is not particularly limited as long as it can be uniformly dispersed. Examples thereof include a stirring blade, a dissolver, a homomixer, and an ultrasonic homogenizer. Such processing may be performed in combination of two or more. In step (e), in addition to water, an aqueous solvent miscible with water and other additives may be added. For example, surfactants, pigment derivatives, other pigments, and the like can be added. These are not particularly limited as long as they do not hinder the dispersibility of the pigment, but are preferably soluble in water. By using a dispersion aid, the dispersibility of the pigment can be improved, and re-aggregation of the pigment after dispersion can be more effectively prevented.

  As the water used in the step (e), it is preferable to use ion-exchanged water (deionized water) instead of general water containing various ions.

(Basic compound)
Examples of basic compounds include lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, triethylamine, tributylamine, dimethylethanolamine, ethanolamine, diethanolamine, triethanolamine, amine methylpropanol, diisopropanolamine, morpholine, and the like. And organic amines.

(Aqueous solvent)
Examples of aqueous solvents include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, triethylene glycol, polyethylene glycol, glycerin, tetraethylene glycol, dipropylene glycol, ketone alcohol, diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, triglyceride. Ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, 1,2-hexanediol, N-methyl-2-pyrrolidone, 2,4,6-hexanetriol, tetrafurfuryl alcohol, 4-methoxy-4methylpentanone, etc. Can be mentioned.

(Surfactant)
As the surfactant, an anionic, cationic, nonionic or amphoteric surfactant or a polymeric surfactant can be used. You may use 2 or more types together as needed.

Anionic surfactants include fatty acid salts, alkyl sulfate salts, alkylaryl sulfonates, alkylnaphthalene sulfonates, dialkyl sulfonates, dialkyl sulfosuccinates, alkyl diaryl ether disulfonates, alkyl phosphates, Polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl aryl ether sulfate, naphthalene sulfonic acid formalin condensate, polyoxyethylene alkyl phosphate ester salt, glycerol borate fatty acid ester, polyoxyethylene glycerol fatty acid ester, etc. .

Examples of the cationic surfactant include alkylamine salts, quaternary ammonium salts, alkylpyridinium salts, alkylimidazolium salts, and the like.

Nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene oxypropylene block copolymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester , Polyoxyethylene fatty acid ester, polyoxyethylene alkylamine and the like.

Examples of amphoteric surfactants include alkylbetaines, alkylamine oxides, phosphadylcholines and the like.

Examples of the polymer surfactant include acrylic water-soluble resins, styrene / acrylic water-soluble resins, water-soluble polyester resins, and water-soluble polyamide resins.

The amount of the surfactant to be added is preferably 0.1 to 55% by mass, more preferably 0.1 to 45% by mass, based on the total amount of the added pigment (100% by mass).

(Dye derivative)
Examples of the dye derivative include a compound in which a basic substituent, an acidic substituent, or a phthalimidomethyl group which may have a substituent is introduced into an organic pigment, anthraquinone, acridone, or triazine. -305173, JP-B-57-15620, JP-B-59-40172, JP-B-63-17102, JP-B-5-9469 and the like can be used alone. Alternatively, two or more types can be mixed and used. When using a dye derivative, those having an azo skeleton, a naphthol azo skeleton, a diketopyrrolopyrrole skeleton, an anthraquinone skeleton, a quinophthalone skeleton, and a perylene skeleton are preferable from the viewpoints of lightness and dispersibility.

  The blending amount of the pigment derivative is preferably 0.5% by mass or more, more preferably 1% by mass or more, and further preferably from the viewpoint of improving the dispersibility of the additive pigment, based on the total amount of the additive pigment (100% by mass). 3% by mass or more. Further, from the viewpoint of heat resistance and light resistance, the total amount of the additive pigment is preferably 40% by mass or less based on the total amount (100% by mass).

  Through the above steps, the pigment composition according to the present invention is obtained. According to the method for producing a pigment composition of the present invention, by using a water-soluble organic solvent satisfying (i) to (iv), the dispersibility of the obtained pigment composition becomes excellent. This is considered to be caused by the fact that the resin adsorption rate to the pigment is improved by performing the steps (a) to (e) using a water-soluble organic solvent as compared with the conventional production method.

In FIG. 1, an example of the preferable embodiment of the manufacturing method of the pigment composition of this invention is demonstrated. As a preferred embodiment, the steps of routes r1 and r2 shown in FIG. 1 can be exemplified.
The route r2 which performs a process (e) after a process (c) other than the route r1 which performs a process (a)-a process (e) and obtains powder is mentioned. The pigment composition obtained by the route r1 is in a powder form, and the pigment composition obtained by the route r2 is, for example, in the form of a varnish dispersed in water. In addition, the pigment composition of this invention should just contain process (a)-process (c), (e), and process (d) can be added arbitrarily. In addition, other steps can be arbitrarily added without departing from the spirit of the present invention.

  The preferred production method may vary depending on the type of product or the needs, but from the viewpoint of simplicity of the production process, a method of directly adding water as shown by route r2 in FIG. 1 is preferred. Moreover, as a method of taking out as a powder, the route r1 is preferable from the viewpoint of simplicity of the manufacturing process. Further, from the viewpoint of further improving the dispersibility of the obtained pigment composition, it is preferable to perform a dry pulverization treatment when removing water in the step (d) of the route r1.

(Inkjet ink)
Next, the case where the pigment composition of this invention is applied to inkjet ink is demonstrated. In order to maintain the suitability as an inkjet ink, the inkjet ink can produce cyan, magenta, yellow, and black inks by mixing penetrants, preservatives, and chelating agents.

  A penetrant is added for the purpose of accelerating ink penetration into paper and speeding up apparent dryness when the substrate to be printed is a penetrable material such as paper. Glycol ethers such as diethylene glycol monobutyl ether, alkylene Examples thereof include glycol, polyethylene glycol monolauryl ether, sodium lauryl sulfate, sodium dodecylbenzenesulfonate, sodium oleate, and sodium dioctylsulfosuccinate. These are used in the range of 0 to 5% by mass, preferably 0.1 to 5% by mass of the recording liquid. The penetrant has a sufficient effect at the above-mentioned use amount, and if it is more than this, it is not preferable because it causes bleeding of the print and paper loss (print-through).

The preservative is added for the purpose of preventing generation of soot and bacteria in the recording liquid, and includes sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, zinc pyridinethione-1-oxide, 1,2- Examples include benzisothiazolin-3-one and 1-benzisothiazolin-3-one amine salts. These are preferably contained in the recording liquid in the range of 0.05 to 1.0% by mass.

The chelating agent is for sequestering metal ions in the recording liquid, and prevents metal precipitation at the nozzle portion and precipitation of insoluble substances in the recording liquid, ethylenediaminetetraacetic acid, Ethylenediaminetetraacetic acid sodium salt, ethylenediaminetetraacetic acid diammonium salt, ethylenediaminetetraacetic acid tetraammonium salt, and the like are used. These are used in the recording liquid in the range of 0.005 to 0.5 mass%.

Examples of cyan pigments that can be used in the cyan ink produced by the production method of the present invention include C.I. I. Pigment Blue 1, 2, 3, 15: 3, 15: 4, 16, 22, C.I. I. Vat Blue4, 6 etc. are mentioned.

Examples of magenta pigments that can be used in the magenta ink produced by the production method of the present invention include C.I. I. Pigment Red 5, 7, 9, 12, 31, 48, 49, 52, 53, 57, 97, 112, 122, 146, 147, 149, 150, 168, 177, 178, 179, 202, 206, 207, 209 238, 242, 254, 255, 269, C.I. I. Pigment Violet 19, 23, 29, 30, 37, 40, 50 and the like.

Examples of yellow pigments that can be used in the yellow ink produced by the production method of the present invention include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 20, 24, 74, 83, 86, 93, 94, 95, 109, 110, 117, 120, 125, 128, 137, 138, 139, 147, 148, 150, 151, 154, 155, 166, 168, 180, 185, 213 and the like.

Examples of the black pigment that can be used for the black ink produced by the production method of the present invention include carbon black produced by the furnace method and the channel method. For example, these carbon blacks have a primary particle diameter of 11 to 40 mμm (nm), a specific surface area by the BET method of 50 to 400 m ² / g, a volatile content of 0.5 to 10% by mass, and a pH value of 2 to 2. Those having characteristics such as 10 are preferred. The following are mentioned as a commercial item which has such a characteristic. For example, no. 33, 40, 45, 52, 900, 2200B, 2300, MA7, MA8, MCF88 (manufactured by Mitsubishi Chemical), RAVEN1255 (manufactured by Colombian Carbon), REGAL330R, 400R, 660R, MOGUL L, ELFTEX415 (manufactured by Cabot) ), Nexex90, Nipex150T, Nipex 160IQ, Nipex 170IQ, Nipex 75, Printex 85, Printex 95, Printex 90, Printex 35, Printex U (manufactured by Evonik Degussa), etc., which can be preferably used.

Colored pigments other than those described above can also be used, and even in such cases, any pigment may be used alone in each color ink, or two or more pigments may be mixed. Of course, the present invention is not limited to these. Newly produced pigments can also be used.

A water-based medium suitable for forming an ink-jet ink using the pigment composition obtained by the production method of the present invention is a mixed solvent of water and a water-soluble solvent, but water contains various ions. It is preferable to use ion-exchanged water (deionized water) instead of ordinary water.

As the water-soluble solvent used by mixing with water, glycol ethers and diols are preferable, and (poly) alkylene glycol monoalkyl ether and alkanediol having 3 to 6 carbon atoms are particularly effective. These solvents penetrate very rapidly into the substrate. Penetration is fast even for substrates with low solvent absorption, such as coated paper, art paper, and vinyl chloride sheets. Therefore, drying at the time of printing is fast and accurate printing can be realized. Moreover, since the boiling point is high, the function as a moisturizing agent is sufficient.

Specific examples of glycol ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monopentyl ether, diethylene glycol monohexyl ether, triethylene Glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monobutyl ether, propylene glycol monopropyl ether, propylene Glycol monobutyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, and the like.

Specific examples of diols include 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,2-pentanediol, 1,5-pentanediol, Examples include 1,2-hexanediol, 1,6-hexanediol, and 2-methyl-2,4-pentanediol.

Of these, the most effective are diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,2-hexanediol. 2-methyl-2,4-pentanediol. These solvents may be used alone or in combination.

Further, depending on the type of substrate to be printed, water-soluble nitrogen-containing complex such as 2-pyrrolidone, N-methylpyrrolidone, N-ethylpyrrolidone, N-methyloxazolidinone, N-ethyloxazolidinone and the like is used for the purpose of improving the solubility. Ring compounds can also be added. The content of the water-soluble solvent as described above in the ink is generally in the range of 3% by mass to 60% by mass, more preferably 3% by mass to 50% by mass of the total mass of the ink. It is a range. The water content is in the range of 10% to 90% by weight, more preferably 30% to 80% by weight, based on the total weight of the ink.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited by this. In Examples and Comparative Examples, “part” means “part by mass”. First, resins, pigments, dye derivatives, and water-soluble solvents used for preparing inkjet inks as dispersants used in Examples and Comparative Examples will be described.

[resin]
(Synthesis Example 1: Resin A)
After charging 1,000 parts of methyl ethyl ketone into a three-liter four-necked flask equipped with a dropping device, a thermometer, a nitrogen gas inlet tube, a stirring device and a reflux condenser, the temperature of the solution was raised to 78 ° C., A mixture of 700 parts of n-butyl methacrylate, 42 parts of n-butyl acrylate, 150 parts of 2-hydroxyethyl methacrylate, 108 parts of methacrylic acid and 80 parts of tertiary butyl peroxy-2-ethylhexanoate was taken over 4 hours. And dripped. Furthermore, the reaction was continued at the same temperature for 8 hours. The reaction mixture was allowed to cool to room temperature, and diluted by adding methyl ethyl ketone so that the nonvolatile content was 50%, to obtain a solution of Resin A having an acid value of 70 mgKOH / g and a number average molecular weight of 6,000.

(Synthesis Example 2: Resin B)
After charging 1,000 parts of methyl ethyl ketone into a three-liter four-necked flask equipped with a dropping device, a thermometer, a nitrogen gas inlet tube, a stirring device and a reflux condenser, the temperature of the solution was raised to 78 ° C., A mixture of 146 parts of styrene, 551 parts of n-butyl methacrylate, 150 parts of 2-hydroxyethyl methacrylate, 153 parts of methacrylic acid and 20 parts of tertiary butyl peroxy-2-ethylhexanoate was added dropwise over 4 hours. . Furthermore, the reaction was continued at the same temperature for 8 hours. The reaction mixture was allowed to cool to room temperature, and diluted by adding methyl ethyl ketone so that the nonvolatile content was 50%, to obtain a solution of Resin B having an acid value of 100 mgKOH / g and a number average molecular weight of 16,000.

(Synthesis Example 3: Resin C)
A four-necked flask with a capacity of 2 liters equipped with a dehydration tube, thermometer, nitrogen gas introduction tube, and stirring device was added to 100 parts of “Cardura E-10” (a glycidyl ester of a synthetic fatty acid manufactured by Shell Chemical Co., Ltd.), adipine 241 parts of acid, 376 parts of hexahydrophthalic anhydride, 195 parts of neopentyl glycol, 165 parts of trimethylolpropane and 0.5 part of dibutyltin dioxide were heated to 190 ° C. over 5 hours while dehydrating, A dehydration condensation reaction was carried out at the same temperature. Sampling was performed to measure the acid value, and the reaction was terminated so that the target acid value was 60. The reaction mixture is allowed to cool and then diluted by adding methyl ethyl ketone so that the non-volatile content is 65%. The acid value is 61, the number average molecular weight is 2,200, the mass average molecular weight is 30,000, and the resin solid content is A solution of Resin C having a hydroxyl value of 60 mgKOH / g was obtained.

(Synthesis Example 4: Resin D)
A four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube was 171 parts of a condensate of neopentyl glycol and adipic acid with a molecular weight of 2,000 and a polytetra with a molecular weight of 2,000. 151 parts of a mixture of methylene glycol and polypropylene glycol and 20 parts of dimethylolpropionic acid were charged, and the temperature was raised to 70 ° C. while stirring under nitrogen gas. Subsequently, 77 parts of isophorone diisocyanate was added and reacted at 90 ° C. until the NCO%, which is the residual ratio of isocyanate groups, reached 3.4 to obtain a linear urethane prepolymer having isocyanate groups at both ends. Subsequently, in a four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser tube, and a nitrogen gas introduction tube, 157 parts of ethyl acetate, 400 parts of isopropyl alcohol, 496 parts of acetone, then 30 parts of isophorone diamine and dinormal butylamine 1.6 parts were added and the temperature was raised to 40 ° C. Next, 419 parts of a linear prepolymer was added and reacted at 40 ° C. for 4 hours to obtain a polyurethane resin D solution having a solid content of 30%.

(Synthesis Example 5: Resin E)
A reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer was charged with 93.4 parts of methyl ethyl ketone and replaced with nitrogen gas. The inside of the reaction vessel was heated to 110 ° C., 35.0 parts of lauryl methacrylate, 35.0 parts of styrene, 30.0 parts of acrylic acid, and V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) 6.0 as a polymerization initiator. Part of the mixture was added dropwise over 2 hours to conduct a polymerization reaction. After completion of the dropwise addition, the mixture was further reacted at 110 ° C. for 3 hours, 0.6 parts of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the reaction was further continued at 110 ° C. for 1 hour to obtain a resin E solution. Obtained. Resin E had a weight average molecular weight of about 16,000.

(Synthesis Example 6: Resin F)
A reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer was charged with 93.4 parts of methyl ethyl ketone and replaced with nitrogen gas. 5. The inside of the reaction vessel is heated to 110 ° C., 35.0 parts of pentadecyl methacrylate, 35.0 parts of styrene, 30.0 parts of acrylic acid, and V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator 0 part of the mixture was added dropwise over 2 hours to carry out the polymerization reaction. After completion of the dropwise addition, the mixture was further reacted at 110 ° C. for 3 hours, 0.6 parts of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the reaction was further continued at 110 ° C. for 1 hour to obtain a resin F solution. Obtained. The mass average molecular weight of the resin F was about 16000.

(Synthesis Example 7: Resin G)
A reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer was charged with 93.4 parts of methyl ethyl ketone and replaced with nitrogen gas. The inside of the reaction vessel was heated to 110 ° C., 50.0 parts of stearyl acrylate, 20.0 parts of styrene, 30.0 parts of acrylic acid, and V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) 6.0 as a polymerization initiator. Part of the mixture was added dropwise over 2 hours to conduct a polymerization reaction. After completion of the dropwise addition, the mixture was further reacted at 110 ° C. for 3 hours, and then 0.6 part of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the reaction was further continued at 110 ° C. for 1 hour to obtain a resin G solution. Obtained. The weight average molecular weight of Resin G was about 16000.

(Synthesis Example 8: Resin H)
A reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer was charged with 93.4 parts of methyl ethyl ketone and replaced with nitrogen gas. The inside of the reaction vessel was heated to 110 ° C., 40.0 parts of behenyl acrylate, 20.0 parts of styrene, 40.0 parts of acrylic acid, and V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) 6.0 as a polymerization initiator. Part of the mixture was added dropwise over 2 hours to conduct a polymerization reaction. After the completion of the dropwise addition, the mixture was further reacted at 110 ° C. for 3 hours, 0.6 parts of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the reaction was further continued at 110 ° C. for 1 hour to obtain a resin H solution. Obtained. The mass average molecular weight of Resin H was about 16000.

The following products were used as the resins I to K as the dispersant.
Resin I: “Watersol S-212” manufactured by DIC
Resin J: “Watersol S-751” manufactured by DIC
Resin K: “Cymel 303” manufactured by Nippon Cytec Industries, Ltd.

[Pigment]
Hereinafter, pigments used in Examples or Comparative Examples are listed.
・ PB15: 3 (1): “LIONOL BLUE FG-7358G” manufactured by Toyocolor Co., Ltd.
・ PB15: 3 (2): “LIONOL BLUE 7919” manufactured by Toyocolor Co., Ltd.
・ PR122 (1): “FASTOGEN Super Magenta RGT” manufactured by DIC
PR122 (2): “CINQUASIA PINK D 4450” manufactured by BASF
・ PR146: “Permanent Carmine FBB02JP” manufactured by Clariant
PR150: “Toshiki Red 150” manufactured by Tokyo Color Material Industries Co., Ltd.
PR269: “Toshiki Red 269” manufactured by Tokyo Color Material Industries Co., Ltd.
・ PR269: “Permanent Carmine 3810” manufactured by Sanyo Dye
-PY14: "SYMULER FAST YELLOW 4400" manufactured by DIC
・ PY74: “FAST YELLOW 7413” manufactured by Sanyo Dye
・ PY120: "INKJET YELLOW H2G" manufactured by Clariant
・ PY150: "BAYSCRIPT YELLOW G01" manufactured by LANXESS
・ PY155: Clariant's “TONER YELLOW4G”
・ PY185: “Paliotol Yellow D1155” manufactured by BASF
・ PV19: "INKJET MAGENTA E5B02" manufactured by Clariant
・ PBk07: “Printex85” manufactured by Orion Engineered Carbons

［水溶性溶剤］
インクジェットインキ作製時の実施例および比較例で用いた水溶性溶剤およびその記号を列挙する。
・１，２−ＨＤ：１，２−ヘキサンジオール
・ＰＧ：プロピレングリコール
・１，３−ＰＤ：１，３−プロパンジオール [Dye derivative]
Hereinafter, the pigment derivatives used in Examples or Comparative Examples are listed in Table 1.

[Water-soluble solvent]
The water-soluble solvents and their symbols used in Examples and Comparative Examples at the time of preparing inkjet inks are listed.
1,2-HD: 1,2-hexanediol PG: propylene glycol 1,3-PD: 1,3-propanediol

A production example of a pigment composition suitable for a paint will be described. In addition, it can apply suitably also for uses other than a coating material.
≪Paint≫
<Preparation of pigment composition by kneading>
[Example 1-1]
(Preparation of pigment composition 101)
PR122 (1) as a pigment ("FASTOGEN Super Magenta RGT" manufactured by DIC) 123.5 parts, 6.5 parts of a pigment derivative a, 400 parts of sodium chloride as a water-soluble inorganic salt, 130 parts of resin A as a dispersant and 350 parts of triacetin Was charged in a stainless gallon kneader (manufactured by Inoue Seisakusho) and kneaded at 80 ° C. for 3 hours. This mixture is added to 10,000 parts of water, stirred at a high speed mixer for about 1 hour while being heated to about 40 ° C. to form a slurry, and repeatedly filtered and washed with water to remove sodium chloride and water-soluble organic solvent. The resultant was dried at 40 ° C. to obtain a pigment composition 101.

[Example 1-2, 3 Comparative examples 1-1 to 3]
(Preparation of pigment compositions 102 to 106)
Pigment compositions 102 to 106 were obtained in the same manner as Example 1-1 except that the kneading composition and kneading conditions shown in Table 2 were changed. However, the resin solution containing the solvent was appropriately replaced with a kneading solvent, or a solid resin dried at 80 ° C. under reduced pressure was used to obtain the composition shown in Table 2.

(Measurement of average primary particle size)
The average primary particle size of the obtained pigment composition was measured using a transmission electron microscope (“JEM-1200EX” manufactured by JEOL Ltd.) and the primary particle size of all pigment particles in the observation sample at a magnification of 100,000 times. The average value was used. In addition, when the particle shape was not spherical, the major axis and the minor axis were measured, and the value obtained by (major axis + minor axis) / 2 was defined as the particle diameter. In addition, the average primary particle diameter of subsequent Examples and Comparative Examples was also measured by the above method.

(Measurement of residual solvent)
The residual solvent is determined by gas chromatography to determine the amount of the residual solvent of the water-soluble organic solvent of the present invention relative to the solid content of the pigment composition. From the ratio of the pigment in the solid content, the amount of the water-soluble organic solvent per 100 parts by mass of the pigment is determined. It calculated | required by calculating the amount of residual solvents.
The conditions for gas chromatography are shown below.
Separation device: GC2010 manufactured by Shimadzu Corporation
Column: DM-5MS (30 mm x 0.25 mm x 0.25 μm Film, Agilent Technologies)
Carrier gas: He
Pressure: 120.0kPa
Total flow rate: 50.0 ml / min
Column flow rate: 1.77 ml / min
Linear velocity: 49.0 cm / sec
Purge flow rate: 3.0 ml / min
Column temperature: held at 80 ° C. for 4 minutes, then heated up in 16 minutes, held at 320 ° C. for 5 minutes Injection mode: Split-less Mode
Injection volume: 1 μl

The conditions of the mass spectrometer are shown below.
Measuring instrument: GCMS-GP2010 manufactured by Shimadzu Corporation
Interface temperature: 250 ° C
Ion source temperature: 200 ° C
Measurement mode: Scan Mode
Measurement range: m / z = 30-500
Measurement time: 5-20min
Event time: 0.5 sec

(Sample preparation method)
0.1 g of the sample is precisely weighed into a 50 ml volumetric flask, and tetrahydrofuran is added to adjust to 50 ml. Thereafter, ultrasonic treatment was performed for 15 minutes, and filtration was performed with a 0.20 μm membrane filter, and the filtrate was used as a measurement sample. In addition, the measurement of the residual solvent of a following example and a comparative example was also measured by the said method.

  Table 2 shows the average primary particle diameters and the residual solvent results of the pigment compositions 101 to 106 obtained in Examples 1-1 to 1-3 and Comparative Examples 1-1 to 1-3.

<Preparation of pigment composition via r1>
[Example 2-1]
(Preparation of pigment composition 201)
After adding water (50 parts) to pigment composition 101 (20 parts), stirring in a dissolver equipped with a toothed disk having a diameter of 4 cm, until the pH of the solution is 8.5 to 9.5. A 10% aqueous dimethylethanolamine solution was added. Further, the mixture was stirred at 70 ° C. and 3000 rpm for 60 minutes, water was added to adjust the non-volatile content to 20%, and a pigment composition 201 was produced. The triacetin concentration per 100 parts by mass of the pigment in the pigment composition 201 was 0.13%.

[Examples 2-2 and 3, Comparative Examples 2-1 to 3]
(Preparation of pigment compositions 202 to 206)
Pigment compositions 202 to 206 were produced in the same manner as in Example 2-1, except that the formulation shown in Table 3 was changed.

(Evaluation of pigment composition)
In order to evaluate the performance of the pigment composition of the present invention, the volume average particle size of the obtained composition was determined by “Microtrac UPA Model 9230” (particle size distribution meter of dynamic light scattering method using laser manufactured by Nikkiso Co., Ltd.). evaluated. An initial evaluation was performed after standing at room temperature for 1 day after dispersion, and a time evaluation was performed after standing for 30 days at room temperature. The results are shown in Table 3.

<Preparation method of paint>
[Example 3-1]
(Preparation of pigment composition 301)
“Watersol S-751” (acrylic resin for baking paints manufactured by DIC Corporation; nonvolatile content = 50%, resin J), “Cymel 303” (melamine resin manufactured by Nihon Cytec Industries, Inc .; active ingredient content = 98% Resin K) and the pigment composition 201 obtained in Example 3-1 were blended so as to have the following composition in a solid amount, diluted by adding water to obtain a pigment composition 301 having a non-volatile component of 24%. Created.
Pigment composition 201: 20 parts Watersol S-751: 28 parts Cymel 303: 12 parts

[Examples 3-2 and 3 and Comparative Examples 3-1 to 3]
(Preparation of pigment compositions 302 to 306)
Pigment compositions 302 to 306 were produced in the same manner as in Example 3-1, except that the pigment composition shown in Table 4 was changed.

The coating material thus obtained was applied on a “BT-144 treated steel plate” (Zinc phosphate treated steel plate manufactured by Nippon Parkerizing Co., Ltd.) using a bar coater so that the film thickness was 20 ± 2 μm. After setting, baking was performed at 150 ° C. for 20 minutes to prepare test pieces of the examples. Each paint was coated on a corona discharge-treated PET film with a bar coater so as to have a film thickness of 10 ± 1 μm, set for 10 minutes, and baked at 150 ° C. for 20 minutes. A test piece of the product was prepared.

(Evaluation in baking paint)
The following evaluation was performed about the pigment composition obtained in Examples 3-1 to 3 and Comparative Examples 3-1 to 3-1. The results are shown in Table 4.

Gloss: What was coated on “BT-144 treated steel plate” was measured with 60 ° specular gloss.

-Color development: What was coated on the PET film was visually determined.
Evaluation criteria A: Color density and concealment are high.
○: Color density and concealment are slightly inferior.
Δ: Color density and concealment are considerably inferior.
X: Color density and hiding properties are considerably inferior and sharpness is low.

Water resistance: What was coated on “BT-144 treated steel plate” was immersed in water at a temperature of 50 ° C., and the occurrence of blisters was determined visually after 48 hours.
Evaluation criteria A: No abnormality at all.
○: Slight blistering was observed.
(Triangle | delta): Generation | occurrence | production of considerable blister was recognized.
X: Blister occurred on the entire surface of the test piece.

  From the results shown in Table 4, it can be understood that the pigment composition obtained by the production method of the present invention is excellent in gloss, color development and water resistance.

≪Gravure / Flexographic ink≫
Next, production examples of a pigment composition suitable for gravure / flexo ink will be described. In addition, it can be suitably applied to uses other than gravure / flexo ink.

<Preparation of pigment composition by kneading>
[Example 4-1]
(Preparation of pigment composition 401)
PB15: 3 (1) (“LIONOL BLUE 7358G” manufactured by Toyocolor Co., Ltd.) 130 parts of sodium chloride, 400 parts of sodium chloride, 120 parts of resin D, and 350 parts of 2-ethyl-1,3-hexanediol, 1 gallon kneader made of stainless steel (Inoue Seisakusho) And kneaded at 120 ° C. for 3 hours. This mixture is added to 10,000 parts of water, stirred at a high speed mixer for about 1 hour while being heated to about 40 ° C. to form a slurry, and repeatedly filtered and washed with water to remove sodium chloride and water-soluble organic solvent. The resultant was dried at 40 ° C. to obtain a pigment composition 401.

[Example 4-2, Comparative examples 4-1 and 2]
(Preparation of pigment compositions 402 to 404)
Pigment compositions 402 to 404 were obtained in the same manner as in Example 4-1, except that the kneading composition and kneading conditions shown in Table 5 were changed. However, the resin solution containing the solvent was appropriately replaced with a kneading solvent, or a solid resin dried at 80 ° C. under reduced pressure was used to obtain the composition shown in Table 5.

  Table 5 shows the average primary particle diameters and the residual solvent results of the pigment compositions 401 to 404 obtained in Examples 4-1 and 2 and Comparative Examples 4-1 and 2.

<Preparation of pigment composition via r1>
[Example 5-1]
(Preparation of pigment composition 501)
The following compounds were blended, stirred in a dissolver equipped with a toothed disk having a diameter of 4 cm at 50 ° C. and 3,000 rpm for 60 minutes, and then filtered under pressure through a membrane filter to give a pigment having a solid content concentration of 26%. A composition 501 was obtained. The concentration of 2-ethyl-1,3-hexanediol per 100 parts by mass of the pigment in the pigment composition 501 was 0.32%.
Pigment composition 401: 25.5 parts 28% aqueous ammonia solution: 0.8 parts Polyethylene wax: 0.5 parts Isopropyl alcohol: 25 parts Water: 48.2 parts

[Example 5-2, Comparative Examples 5-1 and 2]
(Preparation of pigment compositions 502-504)
Pigment compositions 502 to 504 were prepared in the same manner as in Example 5-1, except that the formulation shown in Table 6 was changed.

  As the film, a corona-treated biaxially stretched polypropylene film (P-2161 manufactured by Toyobo Co., Ltd., hereinafter referred to as OPP), a polyethylene terephthalate film (E5100 manufactured by Toyobo Co., Ltd., hereinafter referred to as PET), a nylon film (manufactured by Toyobo Co., Ltd.) N-1102, hereinafter referred to as Ny).

  In the evaluation, ink flow stability, ink tape adhesion, blocking resistance, boil resistance and retort resistance were evaluated. The results are shown in Table 6.

(Ink flow stability)
A: Good fluidity and good gloss of dry ink film B: Poor fluidity and low gloss of dry ink film

(Tape adhesion)
After applying ink to OPP and PET and drying, the cellophane tape is pressure-bonded, and then the tape is peeled off. The peeled state of the ink surface was observed.

(Blocking resistance)
The printed surface of the printed OPP film and the corona discharge treated surface of the OPP film were superposed and left to stand at a temperature of 40 ° C. for 1 day under a load of 3 kg / cm ² . Thereafter, the ink surface and the film surface were peeled off, and the transition of the ink coating to the film surface was evaluated.

(Boil resistance)
After applying an isocyanate-based anchor coating agent to a PET printed material, molten polyethylene was laminated at a thickness of 30 μm by an extrusion laminating machine to obtain a laminated product. Laminated products are made into bags, sealed with a mixture of water / oil / vinegar = 1/1/1 inside, heated in hot water at 90 ° C for 30 minutes, and resists the appearance of the appearance of lambs. Boil suitability was judged.
A: A thing which does not have a lami at all. (Good)
B: Some or all of the delamination occurred. (Bad)

(Retort resistance)
After 3 g / m ² of an isocyanate adhesive was applied to the PET printed material, a polyethylene film having a thickness of 60 μm was laminated by a dry laminating machine to obtain a laminated product. The laminated product was made into a bag, a water / oil mixture was put inside and sealed, and then a retort treatment was performed at 120 ° C./30 minutes, and the suitability of the retort was judged from the presence or absence of the appearance of the lami.
A: A thing which does not have a lami at all. (Good)
B: Some or all of the delamination occurred. (Bad)

  As is clear from Table 6, it was revealed that the pigment composition of the present invention was excellent in each characteristic.

≪Inkjet ink≫
Next, production examples of a pigment composition suitable for inkjet ink will be described. In addition, it can apply suitably also for uses other than the ink for inkjet.

<Preparation of pigment composition by kneading>
[Example 6-1]
(Preparation of pigment composition 601)
PB15: 3 (2) (Toyocolor "LIONOL BLUE 7919") 100 parts, sodium chloride 500 parts, resin E30 parts and 2-ethyl-1,3-hexanediol 250 parts stainless steel 1 gallon kneader (Inoue Manufacturing Co., Ltd.) And kneaded at 100 ° C. for 2 hours. This mixture is added to 10,000 parts of water, stirred at a high speed mixer for about 1 hour while being heated to about 40 ° C. to form a slurry, and repeatedly filtered and washed with water to remove sodium chloride and water-soluble organic solvent. The resultant was dried at 40 ° C. to obtain a pigment composition 601.

[Examples 6-2 to 15 and Comparative Examples 6-1 to 15]
(Preparation of pigment compositions 602 to 630)
Pigment compositions 602 to 630 were obtained in the same manner as in Example 6-1 except that the kneading composition and kneading conditions shown in Table 7 were changed. However, regarding the resin solution containing a solvent, it was used by appropriately substituting it with a kneading solvent, or using a solid resin dried at 80 ° C. under reduced pressure so that the composition shown in Table 7 was obtained.

  Table 7 shows the average primary particle diameters and the residual solvent results of the pigment compositions 601 to 630 obtained in Examples 6-1 to 15 and Comparative Examples 6-1 to 15.

<Preparation of pigment composition via r1>
[Example 7-1]
(Preparation of pigment composition 701)
The following compounds were blended and stirred in a dissolver equipped with a toothed disk having a diameter of 4 cm at 70 ° C. and 3,000 rpm for 60 minutes, followed by pressure filtration with a membrane filter to obtain a pigment composition having a pigment concentration of 13%. A product 701 was obtained. The concentration of 2-ethyl-1,3-hexanediol per 100 parts by mass of the pigment in the pigment composition 701 was 0.45%.
Pigment composition 601: 26 parts Dimethylaminoethanol: 1.1 parts Water: 72.9 parts

[Examples 7-2 to 15, Comparative Examples 7-1 to 15]
(Preparation of pigment compositions 702 to 730)
Pigment compositions 702 to 730 were produced in the same manner as in Example 7-1 except that the blending composition shown in Table 8 was changed.

<Preparation of pigment composition via r2>
[Example 7-16]
(Preparation of pigment composition 731)
PB15: 3 (2) (Toyocolor "LIONOL BLUE 7919") 100 parts, sodium chloride 500 parts, resin E30 parts and 2-ethyl-1,3-hexanediol 250 parts stainless steel 1 gallon kneader (Inoue Manufacturing Co., Ltd.) And kneaded at 100 ° C. for 2 hours. This mixture is put into 10,000 parts of ion-exchanged water, stirred for 1 hour with a high-speed mixer while heating to 40 ± 5 ° C. to form a slurry, and after filtration, 20,000 parts of ion-exchanged water at 40 ± 5 ° C. Washed with. 74.3 parts of a wet cake (solid content concentration 35%) was added to 24.6 parts of ion-exchanged water and 1.1 parts of dimethylaminoethanol, and mixed and stirred at 50 ° C. for 1 hour. The mixture was filtered under pressure with a membrane filter to obtain a pigment composition 725 having a pigment concentration of 13%. The concentration of 2-ethyl-1,3-hexanediol per 100 parts by mass of the pigment in the pigment composition 725 was 0.45%.

[Examples 7-17 to 27, Comparative Examples 7-16 to 27]
(Preparation of pigment compositions 732-754)
Except having changed the compounding composition shown in Table 9, the pigment composition 732-754 was produced like Example 7-16.

  The viscosity, storage stability, haze and resin adsorption rate of the pigment compositions obtained in Examples 7-1 to 15 and Comparative Examples 7-1 to 15 were evaluated by the following methods. Table 8 shows the evaluation results.

  The viscosity, storage stability, haze, and resin adsorption rate of the pigment compositions obtained in Examples 7-16 to 27 and Comparative Examples 7-16 to 27 were evaluated by the following methods. Table 9 shows the evaluation results.

(viscosity)
The viscosity of the pigment composition was measured using an E-type viscometer (“ELD viscometer” manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. under the condition of a rotational speed of 20 rpm.

(Storage stability)
The viscosity after heating for 7 days in a 45 ° C. oven was measured and taken as the viscosity over time. From the initial viscosity value and the time-dependent viscosity value measured before heating, the rate of change with time in viscosity was calculated using the following formula.
[Viscosity change rate with time] = | ([initial viscosity] − [viscosity with time]) / [initial viscosity] | × 100 (%)
Further, the rate of change in viscosity with time was evaluated according to the following criteria.
○: Viscosity change rate with time is less than 10% (good)
Δ: The rate of change in viscosity over time is 10% or more and less than 30% (practicable)
X: The rate of change in viscosity over time is 30% or more (defect)
(Haze value)
Using a spin coater, the substrate coated on glass at 1500 rpm was dried on a hot plate at 100 ° C. for 3 minutes, and the haze of the coated surface was measured with a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd.). It was evaluated with.
○: [Haze value] <3 (good)
Δ: 3 ≦ [haze value] <4.5 (can be implemented)
×: [Haze value] ≧ 4.5 (defect)

(Resin adsorption rate)
To 5 parts of the prepared pigment composition, 15 parts of water was added and shaken well, followed by spinning at 30,000 rpm for 4 hours with an ultracentrifuge. Thereafter, the supernatant was collected, the solid content was measured, and the amount of resin in the supernatant was calculated. The resin adsorption rate was calculated according to the following formula.
Resin adsorption rate = [(initial charged resin amount−resin amount in supernatant) / initial charged resin amount] × 100 (%)
When the resin adsorption rate of the pigment in the pigment composition was 20% or more, it was evaluated as ◯ (good), when it was 15% or more but less than 20%, Δ (practicable), and less than 10% was evaluated as x (bad).

  As is apparent from Tables 8 and 9, it can be seen that the pigment composition of the present invention is excellent in viscosity, storage stability and haze value. This is because the resin adsorption rate for the pigment in the pigment composition of the example is higher than that of the pigment composition of the comparative example.

<Preparation of inkjet ink>
[Example 8-1]
(Pigment composition 801)
The following compounds were stirred and mixed with a disper so as to be uniform, whereby a pigment composition 801 was obtained.
-Pigment composition 701: 25.0 parts-1,2-hexanediol 15.0 parts-Water: 60.0 parts

[Examples 8-2 to 27, Comparative Examples 8-1 to 27]
(Production of pigment compositions 802 to 854)
Pigment compositions 802 to 854 were obtained in the same manner as in Example 8-1, except that the type and blending amount of the pigment composition were changed as shown in Table 10.

<Evaluation of inkjet ink>
The resulting pigment composition (801 to 854) was evaluated for stability over time, printability, and dischargeability by the following methods. Table 10 shows the evaluation results.

(Storage stability over time)
The pigment composition was stored in a thermostat at 70 ° C. for 1 week and accelerated with time, and the change in viscosity of the pigment composition before and after aging was measured. 6 (extremely good) if the absolute value of the rate of change in viscosity before and after storage at 70 ° C. for 1 week is less than 3%, 5 (good) if 3% or more and less than 5%, 4 (5% or more if less than 10%) No problem in practical use) 3 (slightly poor) if 10% or more and less than 15%, 2 (defective) if 15% or more and less than 20%, 1 (very bad) if 20% or more. Those with an evaluation of 4, 5, or 6 have no practical problem. The viscosity of the pigment composition was measured using an E-type viscometer (“ELD type viscometer” manufactured by Toki Sangyo Co., Ltd.) at 25 ° C. and a rotation speed of 50 rpm.

(Printability)
The pigment composition was packed in a cartridge of an ink jet printer ("PM-750C" manufactured by Epson Corporation) and printed on a coated paper (Oji Paper's OK Top Coat +, US basis weight 104.7 g / m < ² >). The printed samples were observed with a magnifying glass to evaluate dot connection and color unevenness. Those with very good printing quality were marked with ◎, those with good quality were marked with ◯, those with good quality were marked with Δ, and those with poor quality were marked with ×.

(Dischargeability)
The pigment composition particles were continuously discharged, and the state of the ejected droplets was observed. The case where there was no ejection failure was marked with ◎, the case where it was hardly seen was marked with ○, the case where it was slightly seen was marked with △, and the case where there were many was marked with ×.

As is apparent from the results in Table 10, all of the examples were better in terms of stability over time, printability, and dischargeability than the comparative examples.

  The pigment composition of the present invention is used in various applications including paints, paper coatings, textile printing, writing instrument inks, printing inks, inkjet inks, cosmetics, and electrostatic toners.

Claims (6)

A step (a) of adding at least a water-soluble inorganic salt, a water-soluble organic solvent and a dispersant to the pigment, and then refining the pigment by milling and kneading;
After step (a), water is added to obtain a suspension (b);
(C) after the step (b), removing the water-soluble inorganic salt and removing the water-soluble organic solvent so as to satisfy the following (A);
After the step (c), the method includes a step (e) of adding water and a basic compound,
The water-soluble organic solvent is a method for producing a pigment composition that satisfies the following (i) to (iv).
(A) The water-soluble organic solvent remains in a range of 0.005 to 0.5 parts by mass per 100 parts by mass of the pigment contained in the pigment composition.
(I) The molecular weight is 100 to 350, more preferably 130 to 350.
(Ii) It has a total of 2 or more functional groups (F) comprising a hydroxyl group and / or an ester group.
(Iii) The viscosity at 60 ° C. is 2 to 140 mPa · s.
(Iv) Does not contain an ether bond. Step (d) for removing water between step (c) and step (e)
The method for producing a pigment composition according to claim 1, comprising:   The water-soluble organic solvent is 2-ethyl-1,3-hexanediol, 2,4-diethyl-1,5-pentanediol, monoacetin, diacetin, triacetin, tripropionine, tributyrin and 2-butyl-2-ethyl-1 The method for producing a pigment composition according to claim 1, wherein the pigment composition is at least one selected from the group consisting of 1,3-propanediol.   The pigment composition according to any one of claims 1 to 3, wherein the pigment is at least one selected from the group consisting of dyed lake pigments, azo pigments, phthalocyanine pigments, and condensed polycyclic pigments. Manufacturing method. A pigment composition comprising a finely divided pigment having an average primary particle size in the range of 5 to 1,000 nm and a water-soluble organic solvent,
A pigment composition comprising 0.005 to 0.5 parts by mass of a water-soluble organic solvent satisfying the following (i) to (iv) per 100 parts by mass of the pigment contained in the pigment composition.
(I) The molecular weight is 130-350.
(Ii) It has a total of 2 or more functional groups (F) comprising a hydroxyl group and / or an ester group.
(Iii) The viscosity at 60 ° C. is 2 to 140 mPa · s.
(Iv) Does not contain an ether bond. An inkjet ink comprising the pigment composition according to claim 5.

Images