JP6315251B2 - Inkjet ink composition - Google Patents

Description

  The present invention relates to an inkjet ink composition.

  The ink jet recording method is capable of recording high-definition images with a relatively simple device, and has been rapidly developed in various fields. Among them, various studies have been made on obtaining a recorded matter having gloss or the like. For example, Patent Document 1 discloses vinyl polymer particles (A), main inks for the purpose of providing an aqueous ink for inkjet recording excellent in glossiness, image clarity, and fixability, and an aqueous dispersion used in the ink. Water for inkjet recording, comprising polymer particles (B) having a hetero atom in the chain, a water-insoluble organic compound (C) and a colorant (D), wherein the colorant (D) is contained in the vinyl polymer particles (A). Dispersions are disclosed and described that the colorant (D) is coated with a polymer.

JP 2007-16075 A

  However, the above-described conventional ink composition containing a colorant coated with a polymer improves the glossiness of the obtained recorded matter, but has a problem that a foreign matter in which the colorant is crystallized is generated.

  The present invention has been made to solve at least a part of the above-described problems, and provides an inkjet ink composition in which the occurrence of foreign matter is suppressed while maintaining the glossiness of the obtained recorded matter. Objective.

  The present inventors diligently studied to solve the above problems. As a result, the inventors have found that the above problem can be solved by including a color material and a color material having a structure similar to the color material, and have completed the present invention.

（一般式（１）中、ＸはＨ、ＮＯ₂又はＯＣＨ₃を示し、ＹはＨ、Ｃｌ、ＣＨ₃、ＯＣＨ₃、ＣＯＮＨ ₂ 、ＳＯ₂ＮＨＣ₆Ｈ₅、ＳＯ ₃ Ｓｒ _1/2 又はＳＯ ₃ Ｃａ _1/2 を示し、ＺはＨ又はＯＣＨ₃を示し、ｘはＨ、Ｃｌ、ＣＨ₃又はＯＣＨ₃を示し、ｙはＨ、Ｃｌ、ＯＣＨ₃、ＯＣ₂Ｈ₅、ＮＨＣＯＣＨ₃又はを示し、ｚはＨ又はＯＣＨ₃を示す。）
〔２〕
前記水不溶性ポリマーで被覆されていない前記Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ ７４、及び、前記水不溶性ポリマーで被覆されていない前記モノアゾ顔料の総含有量が、１００ｐｐｍ〜１．０質量％である、前項〔１〕に記載のインクジェットインク組成物。
〔３〕
可塑剤をさらに含み、
該可塑剤の含有量が、０．０１０〜１．０質量％である、前項〔１〕又は〔２〕に記載のインクジェットインク組成物。
〔４〕
前記水不溶性ポリマーで被覆されていない前記Ｐｉｇｍｅｎｔ Ｙｅｌｌｏｗ ７４又は前記水不溶性ポリマーで被覆されていない前記モノアゾ顔料の可溶化成分をさらに含む、前項〔１〕〜〔３〕のいずれか１項に記載のインクジェットインク組成物。
〔５〕
前記可溶化成分が、トリエチレングリコールモノブチルエーテル及び２−ピロリドンの少なくとも一方を含む、前項〔４〕に記載のインクジェットインク組成物。
〔６〕
前記可溶化成分の含有量が、０．３０〜１２．５質量％である、前項〔４〕又は〔５〕に記載のインクジェットインク組成物。
That is, the present invention is as follows.
[1]
Pigment Yellow 74 coated with a water-insoluble polymer;
A monoazo pigment not covered with a water-insoluble polymer and having a structure represented by the following general formula (1):
Inkjet ink composition.

(In the general formula (1), X represents H, NO ₂ or OCH ₃ , and Y represents H, Cl, CH ₃ , OCH ₃ , CONH ₂ , SO ₂ NHC ₆ H ₅ , SO ₃ Sr _1/2 or SO. _{3 represents} Ca _1/2 , Z represents H or OCH ₃ , x represents H, Cl, CH ₃ or OCH ₃ , y represents H, Cl, OCH ₃ , OC ₂ H ₅ , NHCOCH ₃ or Z represents H or OCH _3. )
[2]
The total content of the Pigment Yellow 74 not coated with the water-insoluble polymer and the monoazo pigment not coated with the water-insoluble polymer is 100 ppm to 1.0% by mass, as described in [1] above. Inkjet ink composition.
[3]
Further comprising a plasticizer,
The inkjet ink composition according to [1] or [2] above, wherein the plasticizer content is 0.010 to 1.0% by mass.
[4]
The pigment yellow 74 that is not coated with the water-insoluble polymer or the solubilizing component of the monoazo pigment that is not coated with the water-insoluble polymer, according to any one of the above items [1] to [3] Inkjet ink composition.
[5]
The inkjet ink composition according to [4], wherein the solubilizing component contains at least one of triethylene glycol monobutyl ether and 2-pyrrolidone.
[6]
The inkjet ink composition according to [4] or [5] above, wherein the content of the solubilizing component is 0.30 to 12.5% by mass.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. However, the present invention is not limited to this, and various modifications can be made without departing from the gist thereof. Is possible. In the present specification, “(meth) acrylate” means both acrylate and the corresponding methacrylate. In the present specification, “(iso or tertiary)” and “(iso)” mean both cases in which these groups are present and cases in which these groups are not present. Indicates normal.

（一般式（１）中、ＸはＨ、ＮＯ₂又はＯＣＨ₃を示し、ＹはＨ、Ｃｌ、ＣＨ₃、ＯＣＨ₃、ＣＯＮＨ ₂ 、ＳＯ₂ＮＨＣ₆Ｈ₅、ＳＯ ₃ Ｓｒ _1/2 又はＳＯ ₃ Ｃａ _1/2 を示し、ＺはＨ又はＯＣＨ₃を示し、ｘはＨ、Ｃｌ、ＣＨ₃又はＯＣＨ₃を示し、ｙはＨ、Ｃｌ、ＯＣＨ3、ＯＣ₂Ｈ₅、ＮＨＣＯＣＨ₃又はを示し、ｚはＨ又はＯＣＨ₃を示す。）
[Inkjet ink composition]
The inkjet ink composition of the present embodiment (hereinafter also referred to as “ink composition”) includes Pigment Yellow 74 coated with a water-insoluble polymer, Pigment Yellow 74 not coated with a water-insoluble polymer, and water-insoluble. And at least one monoazo pigment having a structure represented by the following general formula (1) which is not coated with a polymer.

(In the general formula (1), X represents H, NO ₂ or OCH ₃ , and Y represents H, Cl, CH ₃ , OCH ₃ , CONH ₂ , SO ₂ NHC ₆ H ₅ , SO ₃ Sr _1/2 or SO. _{3 represents} Ca _1/2 , Z represents H or OCH ₃ , x represents H, Cl, CH ₃ or OCH ₃ , y represents H, Cl, OCH 3, OC ₂ H ₅ , NHCOCH ₃ or z represents H or OCH _3. )

[Pigment Yellow 74 coated with water-insoluble polymer]
By including Pigment Yellow 74 coated with a water-insoluble polymer, the ink composition of the present embodiment further improves the print density, glossiness, and image clarity of the obtained recorded matter. “Coated” means that a water-insoluble polymer is attached to at least a part of the surface of the pigment yellow 74 particle.

  Although it does not specifically limit as a water-insoluble polymer, For example, what contains a basic group containing monomer unit, a macromer unit, and / or a hydrophobic monomer unit is mentioned. Further, the water-insoluble polymer may contain a hydroxyl group-containing monomer unit and other monomer units as necessary. Each unit will be described below.

(Basic group-containing monomer)
Although it does not specifically limit as a basic group containing monomer, For example, a cationic monomer and an anionic monomer are mentioned. Examples thereof include those described in JP-A-9-286939, page 5, column 7, line 24 to column 8, line 29. Here, the basic group is not particularly limited, and examples thereof include a carboxy group, a sulfonic acid group, a phosphoric acid group, an amino group, and an ammonium group.

  Although it does not specifically limit as a cationic monomer, For example, unsaturated, such as N, N-dimethylaminoethyl (meth) acrylate, N- (N ', N'-dimethylaminopropyl) (meth) acrylamide, and vinylpyrrolidone Examples include amine-containing monomers and unsaturated ammonium salt-containing monomers.

  Although it does not specifically limit as an anionic monomer, For example, unsaturated carboxylic acid monomers like acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, 2-methacryloyloxymethyl succinic acid; Unsaturated sulfonic acid monomers such as styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 3-sulfopropyl (meth) acrylate, bis- (3-sulfopropyl) -itaconate; vinyl phosphonic acid, vinyl Unsaturated phosphate monomers such as phosphate, bis (methacryloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, dibutyl-2-acryloyloxyethyl phosphate And the like. Among the anionic monomers, unsaturated carboxylic acid monomers are preferable, and acrylic acid and methacrylic acid are more preferable from the viewpoints of dispersion stability and ejection stability.

  The content of the basic group-containing monomer unit is preferably 2 to 40% by mass, more preferably 2 to 30% by mass, based on the total amount of the water-insoluble polymer, from the viewpoint of dispersion stability of the resulting dispersion. And particularly preferably 3 to 20% by mass.

(Macromer)
Although it does not specifically limit as a macromer, For example, the styrene macromer and aromatic group containing (meth) acrylate macromer which have a polymeric functional group in one terminal are mentioned.

  The number average molecular weight of the macromer is preferably 500 to 100,000, more preferably 1,000 to 10,000. The number average molecular weight of the macromer is measured using polystyrene as a standard substance by gel chromatography using 1 mmol / L dodecyldimethylamine-containing chloroform as a solvent.

  Although it does not specifically limit as a styrene-type macromer, For example, the copolymer of a styrene-type monomer homopolymer or a styrene-type monomer and another monomer is mentioned. Examples of the styrene monomer include styrene, 2-methylstyrene, vinyl toluene, ethyl vinyl benzene, vinyl naphthalene, and chlorostyrene.

  Although it does not specifically limit as an aromatic group containing (meth) acrylate type | system | group macromer, For example, the homopolymer of an aromatic group containing (meth) acrylate or a copolymer of it and another monomer is mentioned. As an aromatic group-containing (meth) acrylate, an arylalkyl having 7 to 22 carbon atoms, preferably 7 to 18 carbon atoms, more preferably 7 to 12 carbon atoms, which may have a substituent containing a hetero atom. A (meth) acrylate having an aryl group having 6 to 22 carbon atoms, preferably 6 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, which may have a group or a substituent containing a hetero atom. Can be mentioned. Examples of the substituent containing a hetero atom include a halogen atom, an ester group, an ether group, and a hydroxy group. Specific examples of such monomers include benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl acrylate, and 2-methacryloyloxyethyl-2-hydroxypropyl phthalate. In particular, benzyl (meth) acrylate is preferred.

  Moreover, it does not specifically limit as a polymerizable functional group which exists in the one terminal of these macromers, For example, an acryloyloxy group or a methacryloyloxy group is preferable.

  Acrylonitrile is preferred as the styrene monomer or other monomer copolymerized with the aromatic group-containing (meth) acrylate.

  Although it does not specifically limit as a styrenic macromer which can be obtained commercially, For example, the brand name of Toa Gosei Co., Ltd., AS-6 (S), AN-6 (S), HS-6 (S) is mentioned. .

  The content of the macromer unit is preferably 1 to 25% by mass and more preferably 5 to 20% by mass with respect to the total amount of the water-insoluble polymer, particularly from the viewpoint of enhancing the interaction with the colorant.

(Hydrophobic monomer)
Although it does not specifically limit as a hydrophobic monomer, For example, an alkyl (meth) acrylate and an aromatic group containing monomer are mentioned.

  Although it does not specifically limit as alkyl (meth) acrylate, For example, what has a C1-C22, preferably C6-C18 alkyl group is preferable, Specifically, methyl (meth) acrylate, ethyl ( (Meth) acrylate, (iso) propyl (meth) acrylate, (iso or tertiary) butyl (meth) acrylate, (iso) amyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso ) Octyl (meth) acrylate, (iso) decyl (meth) acrylate, (iso) dodecyl (meth) acrylate, and (iso) stearyl (meth) acrylate.

  As the aromatic group-containing monomer, a vinyl monomer having an aromatic group having 6 to 22 carbon atoms, preferably 6 to 12 carbon atoms, which may have a substituent containing a hetero atom, is preferable. And styrene monomers and aromatic group-containing (meth) acrylates similar to those described for the macromer. Although it does not specifically limit as a substituent containing a hetero atom, For example, a halogen atom, an ester group, an ether group, and a hydroxy group are mentioned.

  The content of the hydrophobic monomer unit is preferably 5 to 98% by mass, more preferably 10 to 60% by mass, based on the total amount of the water-insoluble polymer, from the viewpoints of glossiness and image clarity.

(Hydroxyl group-containing monomer)
Although it does not specifically limit as a hydroxyl-containing monomer, For example, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, polyethyleneglycol (meth) acrylate (n = 2-30, n is an oxyalkylene group) The average number of moles added, the same applies hereinafter), polypropylene glycol (meth) acrylate (n = 2 to 30), poly (ethylene glycol / propylene glycol) (meth) acrylate (oxyethylene group: n = 1 to 15, oxy Propylene group: n = 1-15). Among these, 2-hydroxyethyl (meth) acrylate, polyethylene glycol monomethacrylate, and polypropylene glycol methacrylate are preferable.

  The content of the hydroxyl group-containing monomer unit is preferably 5 to 40% by mass, more preferably 7 to 20% by mass, based on the total amount of the water-insoluble polymer, from the viewpoint of dispersion stability of the resulting dispersion. .

(Other monomers)
Other monomers are not particularly limited, and examples thereof include compounds represented by the following formula.
CH ₂ = C (R ¹ ) COO (R ² O) _p R ³
Wherein R ¹ is a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, R ² is a divalent hydrocarbon group having 1 to 30 carbon atoms which may have a hetero atom, and R ³ is , A monovalent hydrocarbon group having 1 to 30 carbon atoms which may have a hetero atom, p means an average added mole number, and represents a number of 1 to 60, preferably 1 to 30. )

In the above formula, examples of the hetero atom include a nitrogen atom, an oxygen atom, a halogen atom, and a sulfur atom. Preferable examples of R ¹ include a methyl group, an ethyl group, and an (iso) propyl group. Further, preferred examples of R ² O groups are oxyethylene groups, oxy (iso) propylene group, oxytetramethylene group, oxy heptamethylene group, oxyhexamethylene group and carbon consisting of a combination of two or more of these oxyalkylene The oxyalkylene group of number 2-7 is mentioned. Further, as preferred examples of R ³ , an aliphatic alkyl group having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, an alkyl group having 7 to 30 carbon atoms having an aromatic ring, and 4 carbon atoms having a heterocyclic ring. -30 alkyl groups are mentioned.

  Although it does not specifically limit as said other monomer, For example, methoxypolyethyleneglycol (meth) acrylate (1-30: The value of p in the said formula is shown. The following is the same.), Methoxy polytetramethylene glycol (meth) acrylate (1-30), ethoxy polyethylene glycol (meth) acrylate (1-30), octoxypolyethylene glycol (meth) acrylate (1-30), polyethylene glycol (meth) acrylate 2-ethylhexyl ether (1-30), ( Iso) propoxypolyethylene glycol (meth) acrylate (1-30), butoxypolyethylene glycol (meth) acrylate (1-30), methoxypolypropylene glycol (meth) acrylate (1-30), methoxy (ethyleneglycol) Lumpur propylene glycol) (meth) acrylate (1 to 30, ethylene glycol therein: 1-29) can be mentioned. In these, octoxy polyethylene glycol (meth) acrylate (1-30) and polyethyleneglycol (meth) acrylate 2-ethylhexyl ether (1-30) are preferable.

  Examples of commercially available hydroxyl group-containing monomers and other monomers include Shin-Nakamura Chemical Co., Ltd. polyfunctional acrylate monomers (NK esters) M-40G, 90G, and 230G. PE-90, 200, 350, PME-100, 200, 400, 1000, PP-500, 800, 1000, AP-150, 400, 550, 800, 50 PEP-300 50POEP-800B.

  The content of the other monomer units is preferably 5 to 50% by mass, more preferably 10 to 40% by mass, based on the total amount of the water-insoluble polymer, from the viewpoint of dispersion stability of the resulting dispersion. .

  Mass ratio of basic group-containing monomer unit, macromer unit, and hydrophobic monomer unit (content of basic group-containing monomer unit / (content of macromer unit + content of hydrophobic monomer unit)) is glossy From the viewpoints of properties and image clarity, it is preferably 0.01 to 1, more preferably 0.02 to 0.67, and still more preferably 0.03 to 0.50.

  From the viewpoint of dispersion stability of the resulting dispersion, the total content of the basic group-containing monomer unit and the hydroxyl group-containing monomer unit is preferably 6 to 60% by mass, more preferably 10%, based on the total amount of the water-insoluble polymer. -50 mass%.

  From the viewpoint of dispersion stability of the resulting dispersion, the total content of the basic group-containing monomer unit and other monomer units is preferably 6 to 75% by mass, more preferably 13 with respect to the total amount of the water-insoluble polymer. -50 mass%.

  The total content of the basic group-containing monomer unit, the hydroxyl group-containing monomer unit and other monomer units is preferably 6 to 60% by mass with respect to the total amount of the water-insoluble polymer from the viewpoint of dispersion stability of the resulting dispersion. More preferably, it is 13-50 mass%.

  Although the manufacturing method of a water-insoluble polymer is not specifically limited, For example, the method of Unexamined-Japanese-Patent No. 2009-172971 is mentioned.

  The content of Pigment Yellow 74 coated with the water-insoluble polymer is preferably 0.50 to 12.5% by mass, more preferably 1.0 to 10% by mass, based on the total amount of the ink composition. More preferably, it is 2.5 to 7.5% by mass. When the content of Pigment Yellow 74 coated with the water-insoluble polymer is 0.50% by mass or more, the print density, glossiness, and image clarity of the obtained recorded matter tend to be further improved. In addition, when the content of Pigment Yellow 74 coated with the water-insoluble polymer is 12.5% by mass or less, the generation of foreign matters derived from Pigment Yellow 74 coated with the water-insoluble polymer tends to be further suppressed. is there.

[Pigment Yellow 74 not covered with water-insoluble polymer]
By including Pigment Yellow 74 that is not coated with the water-insoluble polymer, the ink composition according to the present embodiment further suppresses the generation of foreign matters derived from Pigment Yellow 74 that is coated with the water-insoluble polymer.

（一般式（１）中、ＸはＨ、ＮＯ₂又はＯＣＨ₃を示し、ＹはＨ、Ｃｌ、ＣＨ₃、ＯＣＨ₃、ＣＯＮＨ ₂ 、ＳＯ₂ＮＨＣ₆Ｈ₅、ＳＯ ₃ Ｓｒ _1/2 又はＳＯ ₃ Ｃａ _1/2 を示し、ＺはＨ又はＯＣＨ₃を示し、ｘはＨ、Ｃｌ、ＣＨ₃又はＯＣＨ₃を示し、ｙはＨ、Ｃｌ、ＯＣＨ3、ＯＣ₂Ｈ₅、ＮＨＣＯＣＨ₃又はを示し、ｚはＨ又はＯＣＨ₃を示す。）

[Monoazo pigment not coated with water-insoluble polymer]
The ink composition of the present embodiment includes a monoazo pigment having a structure represented by the following general formula (1) that is not coated with a water-insoluble polymer (hereinafter, simply referred to as “monoazo pigment”). Generation | occurrence | production of the foreign material derived from Pigment Yellow 74 coat | covered with the polymer is suppressed more. A monoazo pigment not coated with a water-insoluble polymer also has the same effect as Pigment Yellow 74 not coated with a water-insoluble polymer.

(In the general formula (1), X represents H, NO ₂ or OCH ₃ , and Y represents H, Cl, CH ₃ , OCH ₃ , CONH ₂ , SO ₂ NHC ₆ H ₅ , SO ₃ Sr _1/2 or SO. _{3 represents} Ca _1/2 , Z represents H or OCH ₃ , x represents H, Cl, CH ₃ or OCH ₃ , y represents H, Cl, OCH 3, OC ₂ H ₅ , NHCOCH ₃ or z represents H or OCH _3. )

  Although it does not specifically limit as a monoazo pigment, For example, Pigment Yellow 1, 2, 3, 5, 6, 9, 49, 65, 73, 75, 97, 98, 116, 130, 133, 169 is mentioned.

  The total content of Pigment Yellow 74 not coated with the water-insoluble polymer and the monoazo pigment not coated with the water-insoluble polymer is preferably 100 ppm to 1.0% by mass with respect to the total amount of the ink composition. More preferably, it is 200 ppm-0.75 mass%, More preferably, it is 300 ppm-0.50 mass%. When the total content of Pigment Yellow 74 and the monoazo pigment is 100 ppm or more, the generation of foreign matters derived from Pigment Yellow 74 coated with the water-insoluble polymer tends to be further suppressed. In addition, when the total content of Pigment Yellow 74 and the monoazo pigment is 1.0% by mass or less, the generation of foreign matters derived from Pigment Yellow 74 and the monoazo pigment not coated with the water-insoluble polymer tends to be further suppressed. It is in.

[Plasticizer]
The ink composition preferably further contains a plasticizer. By further including a plasticizer, the print density, glossiness, and image clarity of the resulting recorded product tend to be further improved. Although it does not specifically limit as a plasticizer, For example, aliphatic carboxylic acid ester, aromatic carboxylic acid ester, phosphoric acid ester, cycloalkane (ken) carboxylic acid ester, oxy acid ester, glycol ester, epoxy ester, sulfonamide , Polyester, glyceryl alkyl ether, glyceryl alkyl ester, glycol alkyl ether, glycol alkyl ester, trimethylolpropane ether or ester, pentaerythritol ether or ester. Of these, aliphatic carboxylic acid esters such as dibutyl sebacate are preferred.

  The content of the plasticizer is preferably 0.010 to 1.0% by mass, more preferably 0.030 to 0.7% by mass, and still more preferably 0.000% by mass with respect to the total amount of the ink composition. It is 050-0.50 mass%. When the content of the plasticizer is within this range, the print density, glossiness, and image clarity of the obtained recorded matter tend to be further improved.

[Solubilized components]
Preferably, the ink composition further comprises a solubilizing component of Pigment Yellow 74 not coated with a water-insoluble polymer or a monoazo pigment not coated with a water-insoluble polymer. By further including a solubilizing component, the generation of foreign matters derived from Pigment Yellow 74 and the monoazo pigment tends to be further suppressed.

In the present invention, the solubilizing component is an organic solvent having a solubility parameter (SP value) of 20 to 28 (J / cm ³ ) ^1/2 . For the solubility parameter (SP value), refer to the value calculated from Hansen's atom and atomic group evaporation energy and molar volume (Hansen Solubility Parameters: User's Handbook) ) Is used as the SP value. When the SP value is 20 or less, the solubility of the pigment tends to be further improved. Further, when the SP value is 28 or more, the attacking property to the members constituting the printer such as plastic tends to be further lowered.

  Although it does not specifically limit as a solubilizing component, For example, ethanol (26.0), 2-propanol (23.0), 1-butanol (22.6), 1,3-butanediol (27.2), 1,2-hexanediol (24.5), 1,6-hexanediol (24.6), 1,4-butanediol (27.5), 1,5-propanediol (27.7), 2- Ethyl-1,3-hexanediol (22.7), diethylene glycol (24.3), triethylene glycol (27.0), 2-pyrrolidone (27.9), diethylene glycol monoethyl ether (23.2), diethylene glycol mono Butyl ether (22.2), triethylene glycol monoethyl ether (21.8), triethylene glycol monoethyl ether (2 .5), triethylene glycol monobutyl ether (20.5), dipropylene glycol monoethyl ether (20.8), and the like. Among these, it is preferable that at least one of triethylene glycol monobutyl ether and 2-pyrrolidone is included from the viewpoint of achieving both solubility and gloss of the pigment.

  The content of the solubilizing component is preferably 0.30 to 12.5% by mass, more preferably 0.50 to 10% by mass, and still more preferably 2.0 to the total amount of the ink composition. It is -5.0 mass%. When the content of the solubilizing component is 0.30% by mass or more, the generation of foreign matters derived from Pigment Yellow 74 and the monoazo pigment tends to be further suppressed. Further, when the content of the solubilizing component is 12.5% by mass or less, the color developability tends to be further improved.

〔water〕
The ink composition may contain water. Examples of water include water from which ionic impurities have been removed as much as possible, such as pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, and distilled water, and ultrapure water. In addition, when water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is used, generation of mold and bacteria can be prevented when the ink composition is stored for a long period of time. This tends to improve the storage stability.

  The content of water is preferably 60 to 90% by mass, more preferably 65 to 85% by mass, and further preferably 70 to 80% by mass with respect to the total amount of the ink composition.

〔Organic solvent〕
The ink composition may further contain an organic solvent other than the solubilizing component. The organic solvent is not particularly limited. For example, glycerin (32.4), ethylene glycol (32.2), propylene glycol (28.4), 1,2,6-hexanetriol (30.9), 1 -(2-hydroxymethyl) -2-pyrrolidone (28.2), acetone (19.5), tetrahydrofuran (19.1) and the like. The numerical value in parentheses indicates the SP value.

  The content of the organic solvent is preferably 1.0 to 20% by mass, more preferably 2.5 to 15% by mass, and further preferably 5.0 to 10% by mass with respect to the total amount of the ink composition. %.

[Surfactant]
The ink composition may contain a surfactant. The surfactant is not particularly limited, and examples thereof include acetylene glycol surfactants, fluorine surfactants, and silicone surfactants.

  The acetylene glycol-based surfactant is not particularly limited, and examples thereof include 2,4,7,9-tetramethyl-5-decyne-4,7-diol and 2,4,7,9-tetramethyl-5- Selected from alkylene oxide adducts of decyne-4,7-diol and alkylene oxide adducts of 2,4-dimethyl-5-decyn-4-ol and 2,4-dimethyl-5-decyn-4-ol One or more are preferred. Although it does not specifically limit as a commercial item of an acetylene glycol surfactant, For example, Olfin 104 series, E series of Olphine E1010 (A product made by Air Products Japan, Inc.), Surfynol 465, Surfy Nord 61 (trade name, manufactured by Nissin Chemical Industry CO., Ltd.). One acetylene glycol surfactant may be used alone, or two or more acetylene glycol surfactants may be used in combination.

  The fluorosurfactant is not particularly limited. For example, perfluoroalkyl sulfonate, perfluoroalkyl carboxylate, perfluoroalkyl phosphate, perfluoroalkyl ethylene oxide adduct, perfluoroalkyl betaine, perfluoroalkyl betaine, A fluoroalkylamine oxide compound is mentioned. Although it does not specifically limit as a commercial item of a fluorochemical surfactant, For example, S-144, S-145 (Asahi Glass Co., Ltd. product); FC-170C, FC-430, Fluorard-FC4430 (Sumitomo 3M Co., Ltd. product) FSO, FSO-100, FSN, FSN-100, FS-300 (manufactured by Dupont); FT-250, 251 (manufactured by Neos Co., Ltd.) and the like. A fluorine-type surfactant may be used individually by 1 type, and may use 2 or more types together.

  Examples of silicone surfactants include polysiloxane compounds and polyether-modified organosiloxanes. Although it does not specifically limit as a commercial item of a silicone type surfactant, Specifically, BYK-306, BYK-307, BYK-333, BYK-341, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349 (above trade name, manufactured by Big Chemie Japan Co., Ltd.), KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, KF- 945, KF-640, KF-642, KF-643, KF-6020, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017 (all trade names, manufactured by Shin-Etsu Chemical Co., Ltd.) Is mentioned.

  The content of the surfactant is preferably 0.10 to 1.5% by mass, more preferably 0.10 to 1.25% by mass, and still more preferably 0.8%, based on the total amount of the ink composition. It is 25-1.0 mass%. When the content of the surfactant is within the above range, the gloss tends to be further improved.

[Other ingredients]
The ink composition used in the present embodiment has a storage aid and viscosity to maintain good storage stability and ejection stability from the head, to improve clogging, or to prevent deterioration of the ink composition. Add various additives such as regulators, pH regulators, antioxidants, preservatives, antifungal agents, corrosion inhibitors, and chelating agents to capture metal ions that affect dispersion as appropriate You can also. The ink composition used in the present embodiment is preferably a water-based ink composition containing the largest amount of water among the volatile components from the viewpoint of safety.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. The present invention is not limited in any way by the following examples. In the following, “part” means part by mass.

[Material for ink composition]
The main materials for the ink compositions used in the following examples and comparative examples are as follows.
[Color material]
Water dispersion I: Pigment Yellow 74 aqueous dispersion coated with water-insoluble polymer (I) (see Production Example 1 below, solid content concentration 20% by mass)
Water dispersion II: An aqueous dispersion of Pigment Yellow 74 coated with a water-insoluble polymer (II) (see Production Example 2 below, solid content concentration 20% by mass)
Water Dispersion III: Pigment Yellow 1 aqueous dispersion not coated with a water-insoluble polymer (see Production Example 3 below, solid content concentration 20% by mass)
Water dispersion IV: Pigment Yellow 74 aqueous dispersion not coated with a water-insoluble polymer (see Production Example 4 below, solid content concentration 20% by mass)
[Plasticizer]
Dibutyl sebacate (solubilizing component)
Triethylene glycol monobutyl ether 2-pyrrolidinone [organic solvent]
Glycerin (surfactant)
Olphin E1010

[Production Examples of Water-Insoluble Polymers (I) and (II)]
In a reaction vessel, 20 parts of methyl ethyl ketone, 0.03 part of a polymerization chain transfer agent (2-mercaptoethanol), and 10% by mass of a total of 200 parts of each monomer shown in Table 1 were mixed and mixed, and replaced with nitrogen gas. And a mixed solution was obtained. In Table 1, the unit of the numerical value of each monomer is mass%, and the total is 100.0 mass%.

  On the other hand, the remaining 90% by mass of each monomer shown in Table 1 was charged into a dropping funnel, and 0.27 part of the polymerization chain transfer agent, 60 parts of methyl ethyl ketone and a radical polymerization initiator (2,2′-azobis (2,4 -Dimethylvaleronitrile)) 1.2 parts were added and mixed, and nitrogen gas substitution was sufficiently performed to obtain a mixed solution.

  Under a nitrogen atmosphere, the mixed solution in the reaction vessel was heated to 65 ° C. while stirring, and the mixed solution in the dropping funnel was gradually dropped over 3 hours. After 2 hours at 65 ° C. from the end of dropping, a solution in which 0.3 part of the above radical polymerization initiator was dissolved in 5 parts of methyl ethyl ketone was added, and further aged at 65 ° C. for 2 hours and 70 ° C. for 2 hours to obtain a polymer solution It was. The weight average molecular weight of the obtained polymer was measured by the above method. The results are shown in Table 1.

The details of the compounds shown in Table 1 are as follows.
Styrene macromer (manufactured by Toa Gosei Co., Ltd., trade name: AS-6 (S), number average molecular weight: 6000, polymerizable functional group: methacryloyloxy group)
PP-800 (polypropylene glycol monomethacrylate (propylene oxide average addition mole number = 13, terminal: hydroxy group): manufactured by NOF Corporation, trade name: BLEMMER PP-800)
50POEP-800B (octoxy polyethylene glycol polypropylene glycol monomethacrylate (average number of moles of ethylene oxide added = 8, average number of moles of propylene oxide added = 6, terminal: 2-ethylhexyl group): manufactured by NOF Corporation, trade name: BLEMMER 50POEP- 800B)

[Production Example 1 of Water Dispersion]
30 parts of the polymer obtained by drying the solution of the water-insoluble polymer (I) obtained in the above production example under reduced pressure was dissolved in 70 parts of methyl ethyl ketone, and a neutralizing agent (5N aqueous sodium hydroxide solution) was added therein. The basic group was neutralized by adding 230 parts of an amount of 60% and ion exchange water, and further 65 parts of a diazo pigment (Pigment Yellow 74, manufactured by Sanyo Dye Co., Ltd., trade name: FY7413) as a yellow pigment. It mixed for 1 hour under the temperature of 20 degreeC with the blade | wing. The obtained mixture was subjected to 10-pass dispersion treatment at a pressure of 200 MPa using a microfluidizer (trade name, manufactured by Microfluidics).

  After adding 250 parts of ion-exchanged water to the obtained dispersion and stirring, methyl ethyl ketone was removed at 60 ° C. under reduced pressure, a part of water was further removed, and a 5 μm filter (acetylcellulose membrane, outer diameter: A water-insoluble polymer (solid content concentration of 20% by mass) is removed by filtering with a 25 mL needleless syringe (made by Terumo Corporation) attached with 2.5 cm, Fuji Photo Film Co., Ltd.) and removing coarse particles. An aqueous dispersion I of Pigment Yellow 74 coated with I) was obtained.

[Production Example 2 of Water Dispersion]
Except that the solution of the water-insoluble polymer (II) was used, the same operation as in Production Example 1 was performed to obtain an aqueous dispersion II of Pigment Yellow 74 coated with the water-insoluble polymer (II).

[Production Example 3 of Water Dispersion]
A 4L stainless steel beaker was attached to a rotor-stator type high shear mixer (product name “L4RT-A” manufactured by Silverson) and immersed in an ice bath. In this beaker, about 75 g of Pigment Yellow 1 and 1000 g of water were put and homogenized at 7200 rpm for 15 minutes. To this, 20 mL of an isopropanol solution in which 2.07 g (0.01 mol) of o-acetaniside was dissolved was added, and the mixture was further stirred for 15 minutes.

  In a separate container, 4.35 g (0.025 mol) of sulfanilic acid, 30 mL of 1N HCl and 1.73 g (0.025 mol) of sodium nitrite were mixed at 5-10 ° C. to form a diazonium salt. It was. This was then added to the mixture of Pigment Yellow 1 and o-acetanisidide with stirring to maintain the temperature at about 10 ° C. This mixture was adjusted to pH 5-6 by dropwise addition of 5M sodium hydroxide solution, and further stirred for 2 hours while confirming the progress of the reaction based on the presence or absence of a diazonium salt.

  The mixture was transferred to a Telsonic flow sonicator and sonicated for 2 hours, and the resulting pigment dispersion was purified using a 50 nm diafiltration membrane column and then concentrated to a solids content of 20% Thus, Pigment Yellow 1 aqueous dispersion III not coated with a water-insoluble polymer was obtained.

[Production Example 4 of Water Dispersion]
Except having used Pigment Yellow 74, operation similar to the said manufacture example 3 was performed, and the water dispersion IV of Pigment Yellow 74 was obtained.

[Preparation of ink composition]
Each material was mixed with the composition shown in Table 2 below and stirred sufficiently to obtain each ink composition. Specifically, each ink was prepared by uniformly mixing each material and removing insoluble matter with a filter. In Table 2 below, the numerical unit is mass%, and the total is 100.0 mass%.

※なお、色材の含有量は固形分量である。

* The color material content is the solid content.

[Examples 1-9, Comparative Examples 1-2]
[Optical density]
An ink composition shown in Table 2 was filled in an ink jet printer PX-B700 (manufactured by Seiko Epson), and a patch pattern of 100% Duty was printed on a recording medium in a “plain paper clean” mode to obtain a recorded matter. . As recording media, XEROX P paper (manufactured by Fuji Xerox Co., Ltd.), which is a kind of plain paper, was used. With respect to the obtained recorded matter, the OD value of the patch portion was measured using a Gretag densitometer (manufactured by Gretag Macbeth), and the optical density value (OD value) was evaluated according to the following evaluation criteria. The results are shown in Table 2.
(Evaluation criteria)
A: The OD value was 1.1 or more.
B: The OD value was less than 1.1.

[Glossiness]
The ink composition shown in Table 2 was filled in an ink jet printer PX-B700 (manufactured by Seiko Epson), and a 100% Duty patch pattern was printed on the recording medium in the “glossy paper standard” mode to obtain a recorded matter. . As a recording medium, EPSON photographic paper <glossy> (manufactured by Seiko Epson Corporation), which is a kind of glossy paper, was used. The gloss of 60 ° was measured for the obtained recorded matter using a gloss meter MULTI Gloss 268 (manufactured by Konica Minolta), and the gloss was evaluated according to the following evaluation criteria. The results are shown in Table 2.
(Evaluation criteria)
A: The glossiness was 30 or more.
B: The glossiness was 20 or more and less than 30.
C: The glossiness was less than 20.

[Liquid penetration test]
100 ml of the ink composition shown in Table 2 was filled into a cartridge ICY90L for an ink jet printer PX-B700 (manufactured by Seiko Epson), and left at room temperature (25 ° C.) for 6 months. Thereafter, the ink composition was taken out from the cartridge, and the entire amount was filtered using an MF-Millipore membrane filter (SS 3 microns, aperture 49 mm), and the filtered filter paper was observed with an optical microscope (300 times).
(Evaluation criteria)
A: Foreign matter was not observed.
B: Foreign matter was observed and covered less than 1/10 of the filter area.
C: Foreign matter was observed and covered more than 1/10 of the filter area.

Claims (6)

Pigment Yellow 74 coated with a water-insoluble polymer;
A monoazo pigment not covered with a water-insoluble polymer and having a structure represented by the following general formula (1):
Inkjet ink composition.

(In the general formula (1), X represents H, NO ₂ or OCH ₃ , and Y represents H, Cl, CH ₃ , OCH ₃ , CONH ₂ , SO ₂ NHC ₆ H ₅ , SO ₃ Sr _1/2 or SO. _{3 represents} Ca _1/2 , Z represents H or OCH ₃ , x represents H, Cl, CH ₃ or OCH ₃ , y represents H, Cl, OCH 3, OC ₂ H ₅ , NHCOCH ₃ or z represents H or OCH _3. )   2. The total content of the Pigment Yellow 74 not coated with the water-insoluble polymer and the monoazo pigment not coated with the water-insoluble polymer is 100 ppm to 1.0 mass%. Inkjet ink composition. Further comprising a plasticizer,
The inkjet ink composition according to claim 1 or 2, wherein the content of the plasticizer is 0.010 to 1.0 mass%.   The inkjet ink composition according to any one of claims 1 to 3, further comprising a solubilizing component of the Pigment Yellow 74 not coated with the water-insoluble polymer or the monoazo pigment not coated with the water-insoluble polymer. object.   The inkjet ink composition according to claim 4, wherein the solubilizing component includes at least one of triethylene glycol monobutyl ether and 2-pyrrolidone.   The inkjet ink composition according to claim 4 or 5, wherein the content of the solubilizing component is 0.30 to 12.5% by mass.