JP2009144006A - Water-based ink for inkjet recording - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based ink for inkjet recording having excellent glossiness and stability with time and slight change in glossiness when printed on special paper and a water dispersion to be added to the same. <P>SOLUTION: The water dispersion for inkjet recording includes a colorant, a polymer particle, one or more kinds of water-insoluble organic compounds selected from the group consisting of an ester compound, an ether compound and a sulfonic acid amide compound (except a fatty acid derivative) and an alkanepolyol. The water-based ink for inkjet recording includes the water dispersion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an aqueous ink for inkjet recording and an aqueous dispersion used for the ink.

The ink jet recording system is a recording system in which characters and images are obtained by ejecting ink droplets directly from a very fine nozzle and attaching them to a recording member. This method is widely spread because it is easy to make full color and is inexpensive, and has many advantages such as the ability to use plain paper as a recording member and non-contact with the object to be printed.
Among them, from the viewpoint of weather resistance and water resistance of printed matter, those using pigment-based ink as a colorant have become mainstream. (For example, see Patent Documents 1 to 3)

Patent Document 1 discloses a water-based ink in which a pigment is contained in a vinyl polymer.
Patent Document 2 discloses an aqueous dispersion of vinyl polymer particles or polyester polymer particles containing a colorant, and water, in order to provide a water-based ink for ink-jet recording having high print density and excellent glossiness and image clarity. Although an aqueous dispersion for inkjet recording containing an insoluble organic compound (excluding a fatty acid derivative) is disclosed, it is not satisfactory in the temporal stability of the ink.
Patent Document 3 discloses an ink-jet pigment ink in which the total content of fatty acid derivatives in the pigment ink is 1.0% by mass or less, and the pigment particles are coated with a water-insoluble polymer. It is not satisfactory in sex.

International Publication No. 00/39226 Pamphlet JP 2007-77375 A JP 2003-147236 A

  It is an object of the present invention to provide an aqueous ink for inkjet recording and an aqueous dispersion contained therein, which have excellent gloss, excellent stability over time, and little change in gloss when printed on special paper. To do.

  In the present invention, the maximum weight that can be dissolved in a colorant, polymer particles, and 100 g (20 ° C.) is 5 g or less, and the water is at least one selected from the group consisting of ester compounds, ether compounds, and sulfonic acid amide compounds. Provided are an aqueous dispersion for ink jet recording comprising an insoluble organic compound (excluding a fatty acid derivative) and an alkane polyol having 4 to 12 carbon atoms, and an aqueous ink for ink jet recording containing the same.

  ADVANTAGE OF THE INVENTION According to this invention, it is excellent in glossiness, it is excellent in aging stability, and there is little change of the glossiness at the time of printing on exclusive paper, and the aqueous dispersion for inkjet recording contained in it is provided. be able to.

  The water-based ink for ink-jet recording of the present invention comprises an aqueous dispersion containing an alkane polyol having 4 to 12 carbon atoms and a specific water-insoluble organic compound, and is excellent in gloss and stable over time. Excellent in properties and little change in gloss when printed on special paper. This is presumably because the water-insoluble organic compound is stabilized in the polymer particles by the alkane polyol. Hereinafter, each component used in the present invention will be described.

(Alkane polyol having 4 to 12 carbon atoms)
In the present invention, an alkane polyol having 4 to 12 carbon atoms (hereinafter also simply referred to as “alkane polyol”) is used in order to stabilize the water-insoluble organic compound in the polymer particles.
The alkane polyol having 4 to 12 carbon atoms used in the present invention is a linear or branched alkane polyol having 4 to 12 carbon atoms, preferably 6 to 10 carbon atoms, and more preferably 8 to 10 carbon atoms.
The alkane polyol has 2 or more hydroxyl groups, preferably 2 to 6, and more preferably 2 to 4. The molecular weight of the alkane polyol is preferably from 100 to 500, more preferably from 100 to 300.
Specifically, as the alkanediol having 4 to 12 carbon atoms, 2-butyl-2-ethyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1, 3-butanediol, 1,2-butanediol, 1,5-pentanediol, 2-methyl-2,4-pentanediol, 1,2-pentanediol, 2,4-diethyl-1,5-pentanediol, 1,2,4-trimethyl-1,3-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 1,6-hexanediol, 2 -Ethyl-1,3-hexanediol, 1,2-hexanediol, 1,2-octanediol, 1,2-decanediol, 1,2-dodecanediol and the like.
Examples of the alkanetriol having 4 to 12 carbon atoms include 1,2,6-hexanetriol, 1,2,3-butanetriol, pentanetriol, 1,2,4-butanetriol and the like.
Among these, from the viewpoint of stability over time, alkanediol having 4 to 12 carbon atoms is preferable, alkanediol having 4 to 12 carbon atoms each having a hydroxyl group at adjacent carbon atoms, more preferably 4 to 12 carbon atoms. 1,2-alkanediol is more preferable, and 1,2-butanediol, 1,2-pentanediol, 1,2-hexanediol, and 1,2-octanediol are more preferable.

It is considered that alkane polyol has a high affinity with water-insoluble organic compounds and contributes to stability in polymer particles. From this viewpoint, the absolute value of the difference in the solubility parameter (SP value) between the alkane polyol and the water-insoluble organic compound (hereinafter also simply referred to as “SP value”) is preferably 6 or less, and preferably 5 or less. Is still more preferable, and it is still more preferable that it is 4.5 or less.
The SP value of the alkane polyol is preferably from 11 to 18, and more preferably from 12 to 15.
7-12 are preferable and, as for SP value of a water-insoluble organic compound, 9-11 are still more preferable.

The solubility parameter (SP value) referred to in the present specification was determined based on the following Fedors equation by the Fedors method [Robert F. Fedors, Polymer Engineering and Science, 14, 147-154 (1974)]. The value δ [(MPa) ^1/2 ], which is obtained from the square root of the ratio of the sum of evaporation energy of atoms or atomic groups (Δei) of the chemical structure of the compound to the sum of molar volumes (Δvi).
Fedors equation: δ = (ΣΔei / ΣΔvi) ^1/2

(Water-insoluble organic compound)
In the present invention, the maximum weight (20 ° C.) that can be dissolved in 100 g of water is 5 g or less, and one or more water-insoluble organic compounds selected from the group consisting of ester compounds, ether compounds, and sulfonic acid amide compounds (hereinafter, Simply referred to as “water-insoluble organic compound”).
It is considered that at least a part of the water-insoluble organic compound is contained in the polymer particles to improve its flexibility. As a result, the fusibility of the polymer particles ejected from the nozzles of the ink jet recording apparatus is enhanced, the polymer particles are uniformly diffused on the special paper, and the printing surface becomes smooth, thereby improving the gloss of the printed matter. I think that.
Since the fatty acid derivative does not exhibit the above-described effect in the present invention, the water-insoluble organic compound used in the present invention does not include a fatty acid derivative.
Here, the fatty acid derivative removed from the water-insoluble organic compound used in the present invention refers to a fatty acid monoester compound produced from a monovalent fatty acid which is a saturated or unsaturated aliphatic carboxylic acid and a monohydric alcohol.
More specifically, the fatty acid monoester refers to a monoester compound produced from a saturated or unsaturated aliphatic carboxylic acid having 8 to 22 carbon atoms and an alcohol, such as isotridecyl myristate, methyl stearate, methyl oleate. , Methyl palmitate, methyl behenate and the like. However, these fatty acid derivatives may be contained in the aqueous dispersion of the present invention as long as the object of the present invention is not impaired.

The water-insoluble organic compound preferably has a molecular weight of 100 to 2,000, more preferably a molecular weight of 100 to 1,000, from the viewpoint of improving the glossiness and image clarity of the ink.
The maximum weight (20 ° C.) of the water-insoluble organic compound that can be dissolved in 100 g of water is 5 g or less, preferably 3 g or less, more preferably 1 g or less.
In order to improve the flexibility of the polymer, the water-insoluble organic compound preferably has a LogP value of −1 to 11, more preferably 1 to 9, still more preferably 1.5 to 8, and particularly preferably 2 to 7. preferable.
In addition, from the viewpoint of the interaction between the water-insoluble organic compound and the polymer particles, the value of [[Log P value of the water-insoluble organic compound (A)] − [Log P value of the polymer]] is −4 to 8. It is preferably -2 to 6, more preferably -1.5 to 5, and particularly preferably -1 to 4.
Here, “Log P value” means the logarithmic value of the 1-octanol / water partition coefficient of water-insoluble organic compounds, calculated by the fragment approach by SRC's LOGKOW / KOWWIN Program of KowWin (Syracuse Research Corporation, USA). The KowWin Program methodology is described in the following journal article: Meylan, WM and PH Howard. 1995. Atom / fragment contribution method for using octanol-water partition coefficients. J. Pharm. Sci. 84: 83-92 .). The fragment approach is based on the chemical structure of the compound and takes into account the number of atoms and the type of chemical bond. The LogP value is a numerical value generally used for relative evaluation of the hydrophilicity / hydrophobicity of an organic compound.

The water-insoluble organic compound is preferably an ester compound, an ether compound, or a sulfonic acid amide compound so that the water-insoluble organic compound is easily contained in the polymer particles. (F) An ester having two or more ester or ether bonds in the molecule Or an ether compound and / or (g) one or more ester or ether bonds in the molecule, a carboxy group, a sulfuric acid group, a sulfonic acid group, a phosphonic acid group, a phosphoric acid residue, a carbonyl group, an epoxy group, and An ester or ether compound having one or more functional groups selected from the group consisting of hydroxyl groups is more preferred. (F) The ester or ether bond of the compound is preferably 2 to 3, and may have an ester bond and an ether bond. (G) As for the ester or ether bond of a compound, 1-3 are preferable. The number of functional groups is preferably 1 to 3. A phosphoric acid residue means the remaining phosphoric acid group in which a part of phosphoric acid was esterified.
Among the ester compounds, an ester obtained from a monovalent carboxylic acid or a salt thereof and a polyhydric alcohol, an ester obtained from a polyvalent acid (polyvalent carboxylic acid, phosphoric acid) or a salt thereof and a monohydric alcohol is preferred, and aliphatic. Or it is more preferable to have two aromatic carboxylic acid ester groups or three phosphoric acid ester groups. Examples of the salt include alkali metal salts, alkanolamine salts, ammonium salts and the like. Of the ether compounds, polyhydric alcohol ether compounds are preferred.

As the monovalent carboxylic acid, a linear or branched aliphatic carboxylic acid having 1 to 18 carbon atoms, preferably 2 to 10 carbon atoms (for example, acetic acid, butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, Linear aliphatic carboxylic acids such as palmitic acid, branched aliphatic carboxylic acids such as pivalic acid, unsaturated aliphatic carboxylic acids such as acrylic acid and methacrylic acid), and aromatic carboxylic acids having 6 to 12 carbon atoms (for example, , Benzoic acid) and the like.
Examples of the polyvalent acid include aliphatic carboxylic acids having 2 to 12 carbon atoms such as maleic acid, fumaric acid, itaconic acid, succinic acid, adipic acid and sebacic acid; and 6 to 12 carbon atoms such as phthalic acid and trimellitic acid. Aromatic carboxylic acid, phosphoric acid and the like can be mentioned.
The monohydric alcohol is a linear or branched aliphatic alcohol having 1 to 18 carbon atoms, preferably 2 to 10 carbon atoms (for example, ethyl alcohol, butyl alcohol, hexyl alcohol, octyl alcohol, decyl alcohol, dodecyl alcohol). , Aromatic alcohols having 6 to 12 carbon atoms (for example, phenol) and alkylene oxide compounds thereof.
Examples of the polyhydric alcohol include C2-C12 polyhydric alcohols such as ethylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol, and glycerin, and alkylene oxide compounds thereof. A saturated or unsaturated fatty acid or alcohol can be used.
Specific examples of the water-insoluble organic compound include (1) aliphatic carboxylic acid ester, (2) aromatic carboxylic acid ester, (3) cycloalkane (ken) carboxylic acid ester, (4) phosphoric acid ester, (5) Oxyacid ester, (6) glycol ester, (7) epoxy ester, (8) sulfonamide, (9) polyester, (10) glyceryl alkyl ether, (11) glyceryl alkyl ester, (12) glycol alkyl ether, ( 13) glycol alkyl ester, (14) ether or ester of trimethylolpropane, (15) ether or ester of pentaerythritol, and the like.
Among these, from the viewpoints of image clarity and gloss, the compounds (1) to (5), (8) and (10) are preferred, and are aliphatic di- or tricarboxylic acid esters, and (2) aromatic carboxylic acids. More preferably, it is at least one selected from the group consisting of an ester, (3) a cycloalkane (ken) carboxylic acid ester, and (4) a phosphoric acid ester, an aliphatic dicarboxylic acid ester, an aromatic di- or tricarboxylic acid ester, Most preferably, it is at least one selected from the group consisting of cycloalkane (ken) carboxylic acid esters and phosphate esters.
(1) Aliphatic carboxylic acid ester, (2) aromatic carboxylic acid ester, and (3) cycloalkane (ken) carboxylic acid ester are preferably compounds represented by the following formula (1).

(.R wherein, R ¹ and R ² are each independently a hydrogen atom, or a hydrocarbon group having 1 to 22 carbon atoms, R ³ is showing a divalent hydrocarbon group having 1 to 18 carbon atoms ¹ and R ² may be the same or different, except when R ¹ and R ² are both hydrogen atoms, R ^{1 to} R ³ may have a substituent, and m and n are Each independently represents an average addition mole number of 0 to 30, and AO represents an alkanediyloxy group.)

R ¹ and R ² are preferably a linear or branched alkyl or alkenyl group having 2 to 18 carbon atoms, more preferably 4 to 12 carbon atoms, and 7 carbon atoms from the viewpoint of improving the gloss of printed matter. -23, preferably an aralkyl group having 7 to 11 carbon atoms, or an aryl group having 6 to 22 carbon atoms, preferably 6 to 10 carbon atoms, specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group. Butyl group, hexyl group, 2-ethylhexyl group, octyl group, dodecyl group, cetyl group, phenyl group, benzyl group and the like. The same applies to the following equations.
R ³ is preferably a divalent aliphatic hydrocarbon group, a cyclic hydrocarbon group or an aromatic hydrocarbon group, preferably 2 to 15 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 carbon atoms. An alkanediyl group (alkylene group) or an alkenylene group having 8 to 8 carbon atoms, an arylene group having 6 to 10 carbon atoms, more preferably a phenylene group, or a cyclic saturated or unsaturated hydrocarbon group having 3 to 8 carbon atoms. Specifically, ethylene group, trimethylene group, propane-1,2-diyl group, tetramethylene group, heptamethylene group, hexamethylene group, pentane-1,5-diyl group, octamethylene group, dodecamethylene group, phenylene Groups and the like. The same applies to the following equations.
m and n are each independently preferably 0 to 20, more preferably 0 to 15, still more preferably 1 to 15, particularly preferably 2 to 14, and most preferably 2 to 12.

AO is the number of carbon atoms such as ethyleneoxy group (EO), propyleneoxy group (trimethyleneoxy group or propane-1,2-diyloxy group) (PO), butyleneoxy group (tetramethyleneoxy group etc.) (BO), etc. 2 to 4 alkanediyloxy groups (alkyleneoxy groups), and when m and n are 2 or more, AO may be the same or different, and when they are different, AO may be added in blocks or randomly. It may be.
Examples of the substituent that R ^{1 to} R ³ may have include halogen atoms such as fluorine, chlorine and bromine atoms, alkoxy groups having 1 to 12 carbon atoms such as methoxy, ethoxy and isopropoxy groups, phenyloxy Aryloxy groups such as oxycarbonyl groups such as methoxycarbonyl groups, acyl groups such as acetyl and benzoyl groups, acyloxy groups such as acetyloxy groups, cyano groups, nitro groups, hydroxyl groups, carboxy groups, oxo groups, epoxy groups , Ether groups, ester groups and the like (these are collectively referred to as “substituents”). These substituents may be one or a combination of two or more.
The substituent that R ³ may have is preferably —CO (O) — (AO) _L —R ⁴ . In the formula, AO is the same as described above. L has the same meaning as m described above, and the preferred range is also the same. R ⁴ has the same meaning as R ¹ described above, and the preferred range is also the same. In this case, R ³ is preferably an aromatic hydrocarbon group.

(1) The aliphatic carboxylic acid ester is more specifically a compound in which, in the formula (1), R ³ is a divalent aliphatic hydrocarbon group which may have a substituent. preferable. Examples of this substituent include the above-described substituents.
Specific examples of the aliphatic carboxylic acid ester include dimethyl adipate, diethyl adipate, dibutyl adipate, diisobutyl adipate, bis (2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, bis (butyldiethylene glycol) adipate, dimethyl sebacate, diethyl sebacate Examples thereof include aliphatic dibasic acid esters such as keto, dibutyl sebacate, bis (2-ethylhexyl) sebacate, diethyl succinate and bis (2-ethylhexyl) azelate. Among these, diethyl adipate, dibutyl adipate, diisobutyl adipate, bis (butyldiethylene glycol) adipate, bis (octoxypolyethylene glycol) adipate (R ¹ and R ² are both 2-ethylhexyl and EO average added moles m and n, respectively) = 1 to 4), bis (octoxypolypropylene glycol) adipate (R ¹ and R ² are both 2-ethylhexyl, average added moles of PO and n = 1 to 6), bis (octoxypolyethyleneglycol / polypropylene) Propylene glycol) adipate (R ¹ and R ² are both 2-ethylhexyl, EO and PO total average addition moles m and n = 4-12, block addition), bis [octoxypoly (ethylene glycol propylene glycol)] adipate (R ¹ and R ² are both 2 -Ethylhexyl, EO and PO total average addition moles m and n = 4-12, random addition), diethyl sebacate, dibutyl sebacate, diisobutyl sebacate, etc. Diesters are particularly preferred.

  (2) More specifically, the aromatic carboxylic acid ester is more preferably a compound represented by the following formula (2).

(In the formula, R ¹ and R ² have the same meaning as described above, and may be the same or different. AO, m and n have the same meaning as described above, and m and n are 2 or more. AO may be the same or different.)
Specific examples of aromatic carboxylic acid esters include dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, bis (2-ethylhexyl) phthalate, di-n-octyl phthalate, diisodecyl phthalate, butyl benzyl phthalate, octyl benzyl phthalate, nonyl Phthalic acid esters such as benzyl phthalate, stearyl benzyl phthalate, octyl decyl phthalate, dicyclohexyl phthalate, diphenyl phthalate, bis (dimethylcyclohexyl) phthalate, bis (t-butylcyclohexyl) phthalate, ethyl phthalyl ethyl glycolate, tributyl trimellitate, Trimellitic acid esters such as triisobutyl trimellitate and tri (2-ethylhexyl) trimellitate It is below. Among these, 3 carbon atoms such as phthalic acid diester having an aliphatic alcohol residue having 1 to 5 carbon atoms such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diisobutyl phthalate, octyl benzyl phthalate, nonyl benzyl phthalate, stearyl benzyl phthalate Benzyl phthalate having -18 alkyl groups, bis (octoxypolyethylene glycol) phthalate (R ¹ and R ² are both 2-ethylhexyl, average addition number m of EO and n = 1-5), bis (octoxy Polypropylene glycol) phthalate (R ¹ and R ² are both 2-ethylhexyl, average added moles m and n of PO = 1 to 4), bis (octoxypolyethylene glycol / polypropylene glycol) phthalate (R ¹ and R ² Are both 2-Echi Hexyl, each total average addition mole number m and n = 4 to 12 of EO and PO, block addition), bis [Okutokishipori (ethylene glycol-propylene glycol) phthalate (R ¹ and R ² are both 2-ethylhexyl, EO and The total average number of moles of PO added m and n = 4 to 12, random addition) and the like, and phthalic acid esters such as tributyl trimellitate and triisobutyl trimellitate, The trimellitic acid diester is particularly preferred.

  (3) More specifically, the cycloalkane (ken) carboxylic acid ester is more preferably a cyclohexane (cene) carboxylic acid ester represented by the following formula (3). Examples of the cycloalkane (ken) group include a cyclic hydrocarbon group which may have one unsaturated group having 3 to 8 carbon atoms.

(In the formula, R ¹ and R ² have the same meaning as described above, and may be the same or different. AO, m and n have the same meaning as described above, and m and n are 2 or more. AO may be the same or different.)
Specific examples of the cycloalkane (ken) carboxylic acid ester include cyclohexane carboxylic acid esters such as 1,2-cyclohexanedicarboxylic acid dibutyl ester, 1,2-cyclohexanedicarboxylic acid diisononyl ester, and 3,4-cyclohexene dicarboxylic acid dibutyl ester. And cyclohexene carboxylic acid esters such as 3,4-cyclohexene carboxylic acid diisononyl ester.
(4) The phosphate ester is preferably a compound represented by the following formula (4).

(In the formula, R ¹ and R ² have the same meaning as described above and may be the same or different.)
Specific examples of phosphate esters include tributyl phosphate, tris (2-ethylhexyl) phosphate, tris (butoxyethyl) phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, 2-ethylhexyl diphenyl A phosphate etc. are mentioned. Among these, phosphate esters having a C5-C9 alkoxyalkyl group such as tris (butoxyethyl) phosphate, phosphate esters having a C4-12 aliphatic hydrocarbon group such as tributyl phosphate, tris ( Butoxyethyl) phosphates, tricresyl phosphates, trixylenyl phosphates, cresyl diphenyl phosphates, and other phosphate esters having an aromatic hydrocarbon group of 7 to 12 carbon atoms are particularly preferred. The phosphoric acid ester is preferably a phosphoric acid di- or triester.

  (5) The oxyacid ester is preferably a compound represented by the following formula (5).

(In the formula, R ¹ , R ² and R ³ have the same meaning as described above. R ¹ and R ² may be the same or different.)
Specific examples of the oxyester include triethyl acetylcitrate, tributyl acetylcitrate, methyl acetylricinoleate and the like.

  (6) The glycol ester is preferably a compound represented by the following formula (6).

(In the formula, R ¹ , R ² and R ³ have the same meaning as described above. R ¹ and R ² may be the same or different.)
Specific examples of the glycol ester include diethylene glycol dibenzoate and triethylene glycol di (2-ethylhexoate).

  (7) The epoxy ester is preferably a compound represented by the following formula (7).

(In the formula, R ¹ has the same meaning as described above. R ⁴ and R ⁵ each independently represents a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, and R ⁶ represents an alkanediyloxy group having 1 to ⁶ carbon atoms. Show.)
Specific examples of the epoxy ester include butyl epoxy stearate and octyl epoxy stearate.

  (8) The sulfonamide is preferably a compound represented by the following formula (8).

(In the formula, R ¹ and R ² have the same meaning as described above and may be the same or different.)
Specific examples of the sulfonamide include o- and p-toluenesulfonamide, N-butylbenzenesulfonamide and the like.

  (9) The polyester is preferably a compound represented by the following formula (9).

(In the formula, R ¹ , R ² and R ³ have the same meaning as described above and may be the same or different. P represents a number of 1 to 18, preferably 1 to 10.)
Specific examples of the polyester include poly (1,2-butanediol adipate), poly (1,3-butanediol adipate) and the like.
(10) Specific examples of the glyceryl alkyl ether include glyceryl monoether, glyceryl diether, and glyceryl triether. In these, the glyceryl monoether which has a C8-C30 linear or branched alkyl group is preferable. The alkyl group has 8 to 30 carbon atoms, preferably 8 to 22 carbon atoms, and more preferably 8 to 14 carbon atoms.
Examples of the alkyl group include 2-ethylhexyl, (iso) octyl, (iso) decyl, (iso) dodecyl, (iso) myristyl, (iso) cetyl, (iso) stearyl, and (iso) behenyl groups.
There is no restriction | limiting in particular about the position of an alkyl group, Either 1-alkyl glyceryl monoether and 2-alkyl glyceryl monoether may be sufficient.

(11) Specific examples of the glyceryl alkyl ester include glyceryl monoalkyl ester, glyceryl dialkyl ester, and glyceryl trialkyl ester.
Among these, a linear or branched aliphatic carboxylic acid having 1 to 18 carbon atoms, preferably 2 to 10 carbon atoms (for example, acetic acid, butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, palmitic acid) Linear aliphatic carboxylic acids such as branched aliphatic carboxylic acids such as pivalic acid) esters are preferred. The total carbon number of the alkyl group is preferably 6 or more, and more preferably 8 or more.
More specifically, glyceryl triacetate, glyceryl diacetate, glyceryl monoacetate and the like can be mentioned.

  (12) Specific examples of glycol alkyl ether include glycol monoalkyl ether and glycol dialkyl ether. Examples of the glycol of the compound (12) include ethylene glycol and neopentyl glycol, and the alkyl group is a straight chain having 1 to 22 carbon atoms, preferably 6 to 20 carbon atoms, more preferably 8 to 18 carbon atoms. Or a branched alkyl group is mentioned.

(Coloring agent)
The colorant used in the present invention is not particularly limited, and pigments, hydrophobic dyes, water-soluble dyes (acid dyes, reactive dyes, direct dyes, etc.) can be used, but water resistance, dispersion stability and resistance From the viewpoint of abrasion, pigments and hydrophobic dyes are preferable. Among them, it is preferable to use a pigment in order to express the high weather resistance which has been recently demanded.
When the pigment and the hydrophobic dye are used in an aqueous ink, it is necessary to use a surfactant and a polymer to form fine particles that are stable in the ink. In particular, from the viewpoints of bleeding resistance, water resistance, and the like, it is preferable to include a pigment and / or a hydrophobic dye in the polymer particles.
The pigment may be either an inorganic pigment or an organic pigment. If necessary, they can be used in combination with extender pigments.
Examples of the inorganic pigment include carbon black, metal oxide, metal sulfide, and metal chloride. Of these, carbon black is preferred particularly for black aqueous inks. Examples of carbon black include furnace black, thermal lamp black, acetylene black, and channel black.
Examples of the organic pigment include azo pigments, diazo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, dioxazine pigments, perylene pigments, perinone pigments, thioindigo pigments, anthraquinone pigments, and quinophthalone pigments.
Specific examples of preferred organic pigments include C.I. I. Pigment yellow, C.I. I. Pigment Red, C.I. I. Pigment violet, C.I. I. Pigment blue, and C.I. I. One or more types of products selected from the group consisting of pigment green are listed.
Examples of extender pigments include silica, calcium carbonate, and talc.

The hydrophobic dye is not particularly limited as long as it can be contained in the polymer particles. The hydrophobic dye is dissolved in an amount of 2 g / L or more, preferably 20 to 500 g / L (25 ° C.) with respect to the organic solvent (preferably methyl ethyl ketone) used in the production of the polymer from the viewpoint of efficiently containing the dye in the polymer. What to do is desirable.
Examples of the hydrophobic dye include oil-soluble dyes and disperse dyes. Among these, oil-soluble dyes are preferable.
Examples of the oil-soluble dye include C.I. I. Solvent Black, C.I. I. Solvent Yellow, C.I. I. Solvent Red, C.I. I. Solvent Violet, C.I. I. Solvent Blue, C.I. I. Solvent Green, and C.I. I. One or more types of products selected from the group consisting of Solvent Orange are listed, which are commercially available from Orient Chemical Co., Ltd., BASF Corp. and others.
The above colorants can be used alone or in admixture of two or more at any ratio.

(Polymer particles)
In the present invention, the polymer particles are used to improve glossiness by interaction with a water-insoluble organic compound. Moreover, in order to disperse | distribute a coloring agent stably, it is preferable to contain a coloring agent in a polymer particle.
Examples of the polymer used for the polymer particles include polyester, polyurethane, and vinyl polymer. From the viewpoint of dispersion stability, a vinyl polymer obtained by addition polymerization of a vinyl monomer (vinyl compound, vinylidene compound, vinylene compound) is used. preferable.
The polymer is preferably a water-insoluble polymer in order to easily contain a water-insoluble organic compound. Here, the water-insoluble polymer means that when the polymer is dried at 105 ° C. for 2 hours and then dissolved in 100 g of water at 25 ° C., the dissolution amount is 10 g or less, preferably 5 g or less, more preferably 1 g or less. Is a polymer. When the polymer has a salt-forming group, the dissolution amount is a dissolution amount when the salt-forming group of the polymer is neutralized 100% with acetic acid or sodium hydroxide depending on the type.

(Vinyl polymer)
As the vinyl polymer, (a) a salt-forming group-containing monomer (hereinafter sometimes referred to as “(a) component”), (b) a macromer (hereinafter sometimes referred to as “(b) component”) and / or (c ) A vinyl polymer obtained by copolymerizing a monomer mixture (hereinafter also referred to as “monomer mixture”) containing a hydrophobic monomer (hereinafter also referred to as “component (c)”) is preferable. This vinyl polymer has a structural unit derived from the component (a), a structural unit derived from the component (b) and / or a structural unit derived from the component (c). A more preferable vinyl polymer has a structural unit derived from the component (a) or a structural unit derived from the components (a) and (c) as a main chain, and a graft having a structural unit derived from the component (b) as a side chain. It is a polymer.

(A) The salt-forming group-containing monomer is used from the viewpoint of enhancing the dispersion stability of the resulting dispersion. Examples of the salt-forming group include a carboxy group, a sulfonic acid group, a phosphoric acid group, an amino group, and an ammonium group. A carboxy group is particularly preferable.
Examples of the salt-forming group-containing monomer include a cationic monomer and an anionic monomer. Examples thereof include those described in paragraph [0022] of JP-A-9-286939.
Representative examples of the cationic monomer include unsaturated amine-containing monomers and unsaturated ammonium salt-containing monomers. Among these, N, N-dimethylaminoethyl (meth) acrylate, N- (N ′, N′-dimethylaminopropyl) (meth) acrylamide and vinylpyrrolidone are preferable.

Representative examples of anionic monomers include unsaturated carboxylic acid monomers, unsaturated sulfonic acid monomers, unsaturated phosphoric acid monomers, and the like.
Examples of the unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxymethyl succinic acid. Examples of the unsaturated sulfonic acid monomer include styrene sulfonic acid, 2-acrylamido-2-methylpropane sulfonic acid, 3-sulfopropyl (meth) acrylate, bis- (3-sulfopropyl) -itaconic acid ester, and the like. Unsaturated phosphoric acid monomers include vinyl phosphonic acid, vinyl phosphate, bis (methacryloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, dibutyl-2-acryloyloxyciethyl phosphate Etc.
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.

(B) The macromer can be used from the viewpoint of enhancing the dispersion stability of the polymer particles when the polymer particles contain a colorant. The macromer includes a macromer which is a monomer having a polymerizable unsaturated group having a number average molecular weight of 500 to 100,000, preferably 1,000 to 10,000. In addition, the number average molecular weight of (b) macromer is measured using polystyrene as a standard substance by gel chromatography using chloroform containing 1 mmol / L of dodecyldimethylamine as a solvent.
Among (b) macromers, styrenic macromers and aromatic group-containing (meth) acrylate macromers having a polymerizable functional group at one end are preferred from the viewpoint of dispersion stability of polymer particles.
Examples of the styrenic macromer include a styrene monomer homopolymer or a copolymer of a styrene monomer and another monomer. Examples of the styrene monomer include styrene, 2-methylstyrene, vinyl toluene, ethyl vinyl benzene, vinyl naphthalene, chlorostyrene, and the like.
Examples of the aromatic group-containing (meth) acrylate-based macromer include a homopolymer of an aromatic group-containing (meth) acrylate or a copolymer thereof with another monomer. 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. (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 In addition, examples of the substituent containing a hetero atom include a halogen atom, an ester group, an ether group, and a hydroxy group. Examples include benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, and benzyl (meth) acrylate is particularly preferable.
The polymerizable functional group present at one end of the macromer is preferably an acryloyloxy group or a methacryloyloxy group, and the other monomer to be copolymerized is preferably acrylonitrile.
The content of the styrene monomer in the styrene macromer or the aromatic group-containing (meth) acrylate in the aromatic group-containing (meth) acrylate macromer is preferably 50% by weight from the viewpoint of increasing the affinity with the pigment. Above, more preferably 70% by weight or more.

(B) The macromer may have a side chain composed of another structural unit such as an organopolysiloxane. This side chain can be obtained, for example, by copolymerizing a silicone macromer having a polymerizable functional group at one end represented by the following formula (10).
_{CH 2 = C (CH 3)} -COOC 3 H 6 - [Si (CH _{3) 2} O] _{t -Si (CH 3) 3 (} 10)
(In the formula, t represents a number of 8 to 40).
Examples of commercially available styrenic macromers as component (b) include Toa Gosei Co., Ltd. trade names, AS-6 (S), AN-6 (S), HS-6 (S), and the like. It is done.

(C) The hydrophobic monomer is used from the viewpoint of improving printing density, glossiness, and image clarity. Examples of the hydrophobic monomer include alkyl (meth) acrylates and aromatic group-containing monomers.
As the alkyl (meth) acrylate, those having an alkyl group having 1 to 22 carbon atoms, preferably 6 to 18 carbon atoms are preferable. For example, methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meta) ) Acrylate, (iso or tertiary) butyl (meth) acrylate, (iso) amyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate, (iso) Examples include decyl (meth) acrylate, (iso) dodecyl (meth) acrylate, and (iso) stearyl (meth) acrylate.
In the present specification, “(iso or tertiary)” and “(iso)” mean both the case where these groups are present and the case where these groups are not present. Indicates. “(Meth) acrylate” indicates acrylate, methacrylate, or both.

The aromatic group-containing monomer has an aromatic group having 6 to 22 carbon atoms, preferably 6 to 18 carbon atoms, more preferably 6 to 12 carbon atoms, which may have a substituent containing a hetero atom. Vinyl monomers are preferable, and examples thereof include the styrene monomer (c-1 component) and the aromatic group-containing (meth) acrylate (c-2 component). The above-mentioned thing is mentioned as a substituent containing a hetero atom.
Among the components (c), styrenic monomers (component c-1) are preferred from the viewpoint of improving glossiness and printing density. Examples of the styrenic monomers include those described above, and particularly styrene and 2-methylstyrene. preferable. The content of the component (c-1) in the component (c) is preferably 10 to 100% by weight, more preferably 20 to 80% by weight, from the viewpoint of improving printing density and glossiness.

  In addition, examples of the aromatic group-containing (meth) acrylate (c-2) component include those described above, and benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, and the like are preferable. The content of the component (c-2) in the component (c) is preferably 10 to 100% by weight, more preferably 20 to 80% by weight, from the viewpoint of improving glossiness. It is also preferable to use the component (c-1) and the component (c-2) in combination.

The monomer mixture may further contain (d) a hydroxyl group-containing monomer (hereinafter sometimes referred to as “component (d)”). (D) A hydroxyl group-containing monomer is used to further increase the dispersion stability.
As the component (d), for example, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, polyethylene glycol (n = 2 to 30, n represents the average number of added moles of oxyalkylene group. The same)) (meth) acrylate, polypropylene glycol (n = 2-30) (meth) acrylate, poly (ethylene glycol (n = 1-15) / propylene glycol (n = 1-15)) (meth) acrylate, etc. Can be mentioned. Among these, 2-hydroxyethyl (meth) acrylate, polyethylene glycol monomethacrylate, and polypropylene glycol methacrylate are preferable.

The monomer mixture may further contain (e) a monomer represented by the following formula (11) (hereinafter also referred to as “(e) component”).
^{_{CH 2 = C (R 7)}} COO (R 8 O) p R 9 (11)
Wherein R ⁷ is a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, R ⁸ is a divalent hydrocarbon group having 1 to 30 carbon atoms which may have a hetero atom, and R ⁹ 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. )
The component (e) is used to further improve the print density, glossiness, and image clarity of the ink.
In the formula (11), examples of the hetero atom include a nitrogen atom, an oxygen atom, a halogen atom, and a sulfur atom.
Preferable examples of R ⁷ include a methyl group, an ethyl group, and an (iso) propyl group.
Preferable examples of the R ⁸ O group include an oxyethylene group, an oxy (iso) propylene group, an oxytetramethylene group, an oxyheptamethylene group, an oxyhexamethylene group, and a combination of two or more of these oxyalkylenes having 2 carbon atoms. -7 oxyalkylene groups.
Preferable examples of R ⁹ include aliphatic alkyl groups having 1 to 30 carbon atoms, preferably 1 to 20 carbon atoms, alkyl groups having 7 to 30 carbon atoms having an aromatic ring, and 4 to 30 carbon atoms having a heterocyclic ring. Of the alkyl group.

  Specific examples of the component (e) include methoxypolyethylene glycol (1 to 30: the value of p in the formula (11), the same applies hereinafter) (meth) acrylate, methoxypolytetramethylene glycol (1 to 30) ( (Meth) acrylate, ethoxy polyethylene glycol (1-30) (meth) acrylate, octoxy polyethylene glycol (1-30) (meth) acrylate, polyethylene glycol (1-30) (meth) acrylate 2-ethylhexyl ether, (iso) Propoxy polyethylene glycol (1-30) (meth) acrylate, butoxy polyethylene glycol (1-30) (meth) acrylate, methoxypolypropylene glycol (1-30) (meth) acrylate, methoxy (ethylene glycol / propylene glycol) Copolymerization) (1-30, ethylene glycol therein: 1-29) (meth) acrylate. Among these, octoxypolyethylene glycol (1-30) (meth) acrylate and polyethylene glycol (1-30) (meth) acrylate 2-ethylhexyl ether are preferable.

Specific examples of commercially available (d) and (e) components include Shin-Nakamura Chemical Co., Ltd. polyfunctional acrylate monomer (NK ester) M-40G, 90G, 230G, and Nippon Oil & Fats Co., Ltd. BLEMMER series, PE-90, 200, 350, PME-100, 200, 400, 1000, PP-500, 800, 1000, AP-150, 400, 550, 800 , 50PEP-300, 50POEP-800B, and the like.
The components (a) to (e) can be used alone or in admixture of two or more.

The content of the components (a) to (e) in the monomer mixture at the time of polymer production (content as an unneutralized amount; the same applies hereinafter) or derived from the components (a) to (e) in the water-insoluble polymer The content of the structural unit is as follows.
The content of component (a) is preferably 2 to 40% by weight, more preferably 2 to 30% by weight, and particularly preferably 3 to 20% by weight from the viewpoint of dispersion stability of the resulting dispersion.
The content of the component (b) is preferably 1 to 25% by weight, more preferably 5 to 20% by weight, particularly from the viewpoint of enhancing the interaction with the colorant.
The content of the component (c) is preferably 5 to 98% by weight, more preferably 10 to 60% by weight from the viewpoints of glossiness and image clarity.
The content of component (d) is preferably 5 to 40% by weight, more preferably 7 to 20% by weight, from the viewpoint of dispersion stability of the resulting dispersion.
The content of component (e) is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, from the viewpoint of dispersion stability of the resulting dispersion.
The total content of [(a) component + (d) component] in the monomer mixture is preferably 6 to 60% by weight, more preferably 10 to 50% by weight, from the viewpoint of dispersion stability of the resulting dispersion. is there. The total content of [component (a) + component (e)] is preferably 6 to 75% by weight, more preferably 13 to 50% by weight, from the viewpoint of dispersion stability of the resulting dispersion. Further, the total content of [(a) component + (d) component + (e) component] is preferably 6 to 60% by weight, more preferably 7 to 50% from the viewpoint of dispersion stability of the resulting dispersion. % By weight.
Further, the weight ratio of [(a) component / [(b) component + (c) component]] is preferably 0.01 to 1, more preferably 0.02 to 0 from the viewpoints of glossiness and image clarity. .67, more preferably 0.03 to 0.50.

(Manufacture of polymers)
The polymer used in the present invention is produced by copolymerizing a monomer mixture by a known polymerization method such as a bulk polymerization method, a solution polymerization method, a suspension polymerization method or an emulsion polymerization method. Among these polymerization methods, the solution polymerization method is preferable.
The solvent used in the solution polymerization method is not particularly limited, but a polar organic solvent is preferable. When the polar organic solvent is miscible with water, it can be used by mixing with water. Examples of the polar organic solvent include aliphatic alcohols having 1 to 3 carbon atoms such as methanol, ethanol, and propanol; ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; esters such as ethyl acetate. Among these, methanol, ethanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, or a mixed solvent of one or more of these and water are preferable.
In the polymerization, azo compounds such as 2,2′-azobisisobutyronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile), t-butyl peroxyoctate, dibenzoyl oxide, etc. Known radical polymerization initiators such as organic peroxides can be used.
The amount of the radical polymerization initiator is preferably 0.001 to 5 mol, more preferably 0.01 to 2 mol, per mol of the monomer mixture.
In the polymerization, a known polymerization chain transfer agent such as mercaptans such as octyl mercaptan and 2-mercaptoethanol and thiuram disulfide may be further added.

Since the polymerization conditions of the monomer mixture vary depending on the type of radical polymerization initiator, monomer, and solvent used, it cannot be determined unconditionally. Usually, the polymerization temperature is preferably 30 to 100 ° C, more preferably 50 to 80 ° C, and the polymerization time is preferably 1 to 20 hours. The polymerization atmosphere is preferably a nitrogen gas atmosphere or an inert gas atmosphere such as argon.
After completion of the polymerization reaction, the produced polymer can be isolated from the reaction solution by a known method such as reprecipitation or solvent distillation. Further, the obtained polymer can be purified by repeating reprecipitation or by removing unreacted monomers and the like by membrane separation, chromatographic method, extraction method and the like.

The weight average molecular weight of the polymer is preferably from 5,000 to 500,000, more preferably from 10,000 to 400,000, and even more preferably from 10,000 to 300,000, from the viewpoint of printing density, glossiness, and dispersion stability of the colorant. 20,000 to 300,000 is particularly preferable. In addition, the weight average molecular weight of the polymer was measured by the method shown in the Examples.
When the polymer has (a) a salt-forming group derived from a salt-forming group-containing monomer, the polymer is used after being neutralized with a neutralizing agent. As the neutralizing agent, an acid or a base can be used depending on the type of the salt-forming group in the polymer. For example, hydrochloric acid, acetic acid, propionic acid, phosphoric acid, sulfuric acid, lactic acid, succinic acid, glycolic acid, gluconic acid, glyceric acid and other acids, lithium hydroxide, sodium hydroxide, potassium hydroxide, ammonia, methylamine, dimethylamine , Bases such as trimethylamine, ethylamine, diethylamine, triethylamine, triethanolamine, and tributylamine.

The degree of neutralization of the salt-forming group is preferably 10 to 200%, more preferably 20 to 150%, and particularly preferably 50 to 150%.
Here, the degree of neutralization can be determined by the following formulas (12) and (13) when the salt-forming group is an anionic group.
{[Weight of neutralizing agent (g) / equivalent of neutralizing agent] / [acid value of polymer (KOH mg / g) × polymer weight (g) / (56 × 1000)]} × 100 (12)
When the salt-forming group is a cationic group, it can be determined by the following formula.
{[Weight of neutralizing agent (g) / equivalent of neutralizing agent] / [amine value of polymer (HCL mg / g) × polymer weight (g) / (36.5 × 1000)]} × 100 (13)
The acid value and amine value can be calculated from the structural unit of the polymer. Alternatively, it can also be determined by a method in which a polymer is dissolved in an appropriate solvent (for example, methyl ethyl ketone) and titrated. The acid value or amine value of the polymer is preferably 50 to 200, more preferably 50 to 150.

(Production method of water dispersion for inkjet recording)
The aqueous dispersion for inkjet recording of the present invention contains a colorant, polymer particles, a water-insoluble organic compound, and an alkane polyol, and the colorant is preferably contained in the polymer particles. Although there is no limitation in the manufacturing method of such an aqueous dispersion, For example, it can obtain by following process (1)-(3).
Step (1): Step of obtaining a dispersion of polymer particles containing a colorant by dispersing a mixture containing a polymer, an organic solvent, a colorant, water and, if necessary, a neutralizing agent Step (2): Step (1) Step of removing the organic solvent from the obtained dispersion to obtain an aqueous dispersion of polymer particles containing a colorant Step (3): Step (2) The obtained polymer containing a colorant Step of mixing aqueous dispersion of particles, water-insoluble organic compound and alkane polyol

In step (1), first, the polymer is dissolved in an organic solvent, and the resulting organic solvent solution is mixed with a colorant, water, and if necessary, a neutralizing agent, a surfactant, and the like. A method for obtaining an oil-in-water dispersion is preferred. In the mixture, the colorant is preferably 5 to 50% by weight, more preferably 10 to 40% by weight, the organic solvent is preferably 10 to 70% by weight, more preferably 10 to 50% by weight, and the polymer is 2 to 2% by weight. It is preferably 40% by weight, more preferably 3 to 20% by weight, and water is preferably 10 to 70% by weight, more preferably 20 to 70% by weight.
When the polymer has a salt-forming group, it is preferable to use a neutralizing agent, but the degree of neutralization is not particularly limited. Usually, it is preferable that the liquid dispersion of the finally obtained water dispersion is neutral, for example, pH is 4.5 to 10. The pH can also be determined by the desired degree of neutralization of the water-insoluble polymer. Examples of the neutralizing agent include those described above. Further, the polymer may be neutralized in advance.

  Examples of the organic solvent include alcohol solvents such as ethanol, isopropanol and isobutanol, ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone and diethyl ketone, and ether solvents such as dibutyl ether, tetrahydrofuran and dioxane. Preferably, the amount dissolved in 100 g of water is preferably 5 g or more at 20 ° C., more preferably 10 g or more, more specifically preferably 5 to 80 g, more preferably 10 to 50 g, and particularly methyl ethyl ketone. And methyl isobutyl ketone are preferred.

There is no restriction | limiting in particular in the dispersion method of the yes mixture in the said process (1). Although the average particle size of the polymer particles can be atomized until the desired particle size is obtained without pre-dispersing, it is preferably pre-dispersed using a commonly used mixing and stirring device such as a media-type disperser. After that, it is preferable to control the average particle size of the polymer particles to be a desired particle size by further applying a shear stress to perform further dispersion. 5-50 degreeC is preferable and dispersion | distribution of a process (1) has more preferable 10-35 degreeC.
Examples of means for applying a shear stress include a bead mill, a high-pressure homogenizer [Izumi Food Machinery Co., Ltd., trade name], a mini-valve type high-pressure homogenizer represented by Minilab 8.3H type (Rannie Co., trade name), and a microfluidizer [ Microfluidics, trade name], Nanomizer [Nanomizer Co., trade name] and other chamber type high-pressure homogenizers. A plurality of these devices can be combined. Among these, a high-pressure homogenizer is preferable from the viewpoint of reducing the particle size of the pigment.

In the step (2), an aqueous dispersion of polymer particles containing a colorant can be obtained by distilling off the organic solvent from the obtained dispersion by a known method to form an aqueous system. The organic solvent in the aqueous dispersion containing the obtained polymer particles is preferably substantially removed, but may remain as long as the object of the present invention is not impaired. The amount of the residual organic solvent is preferably 0.1% by weight or less, and more preferably 0.01% by weight or less.
The obtained aqueous dispersion of polymer particles containing the colorant is one in which the solid content of the polymer containing the colorant is dispersed in water as the main solvent. Here, the form of the polymer particles is not particularly limited as long as the composite particles are formed of at least a colorant and a polymer. For example, a particle form in which a colorant is included in a polymer, a particle form in which a colorant is uniformly dispersed in a polymer, a particle form in which a colorant is exposed on the surface of a polymer particle, and the like are included.

In the step (3), the water dispersion obtained in the step (2), the water-insoluble organic compound and the alkane polyol may be mixed. Preferably, the water dispersion obtained in the step (2) and the water-insoluble organic compound are mixed and subjected to a dispersion treatment by applying a shear stress, and then an alkane polyol is added. Thereby, an aqueous dispersion of polymer particles containing the water-insoluble organic compound and the colorant, in which at least a part of the water-insoluble organic compound is contained in the polymer particles, can be obtained. The alkane polyol may be present together with the water-insoluble organic compound in the polymer particles, or may be present in the aqueous dispersion.
The means for applying the shear stress is the same as in the step (2). An ultrasonic homogenizer can also be used. For example, as the ultrasonic homogenizer, those having a frequency of 20 to 2000 kHz and a wattage per liter of the total reaction liquid amount of preferably 20 to 1000 W, more preferably 50 to 800 W are desirable. Such an ultrasonic disperser is commercially available from Nippon Seiki Seisakusho, Alex Co., Ltd. A plurality of these devices can be combined. 5-50 degreeC is preferable and dispersion | distribution of a process (3) has more preferable 10-35 degreeC.

The aqueous dispersion for inkjet recording of the present invention may be used as an aqueous ink as it is, but a wetting agent, a penetrating agent, a dispersant, a viscosity modifier, an antifoaming agent, an antifungal agent, an anti-foaming agent that are usually used for an aqueous ink for inkjet recording. A rusting agent or the like may be added. Alternatively, an aqueous dispersion obtained by adding a wetting agent or a penetrating agent together with an alkane polyol in the step (3) may be used as a water-based ink.
The average particle diameter of the polymer particles in the obtained water dispersion and water-based ink is preferably 0.01 to 0.5 μm, more preferably 0.03 to 0.5 from the viewpoint of preventing clogging of the nozzles of the printer and dispersion stability. It is 0.3 μm, particularly preferably 0.05 to 0.2 μm. The average particle diameter can be measured with a laser particle analysis system ELS-8000 (cumulant analysis) manufactured by Otsuka Electronics Co., Ltd. The measurement conditions are a temperature of 25 ° C., an angle between incident light and a detector of 90 °, and an integration count of 100. The refractive index of water (1.333) is input as the refractive index of the dispersion solvent. The measurement concentration is usually about 5 × 10 ⁻³ wt%.

(Water dispersion for inkjet recording / water-based ink)
The content of each component in the aqueous dispersion for ink-jet recording or the aqueous ink of the present invention and the ratio thereof are as follows.
In the aqueous dispersion, the content of the water-insoluble organic compound is preferably 0.1 to 7% by weight, more preferably 0.3 to 5% by weight, and 0.5 to 3% by weight from the viewpoint of improving gloss. Particularly preferred.
In the aqueous dispersion, the content of the polymer particles (the solid content excluding the water-insoluble organic compound and the colorant; the same shall apply hereinafter) is preferably 0.5 to 20% by weight from the viewpoint of printing density and gloss. -15% by weight is more preferred, and 2-10% by weight is particularly preferred.
In the aqueous dispersion, the content of the colorant is preferably 1 to 30% by weight, more preferably 2 to 25% by weight, and particularly preferably 2 to 20% by weight from the viewpoint of printing density.
In the aqueous dispersion, the content of alkane polyol is preferably 0.2 to 10% by weight, more preferably 0.5 to 10% by weight, and more preferably 1 to 5% by weight from the viewpoint of glossiness due to improved stability over time. Particularly preferred.
In the water-based ink, the content of the water-insoluble organic compound is preferably 0.1 to 5% by weight, more preferably 0.2 to 3% by weight, particularly 0.3 to 2% by weight from the viewpoint of improving glossiness. preferable.
In the water-based ink, the content of polymer particles (the solid content excluding the water-insoluble organic compound and the colorant. The same applies hereinafter) is preferably 0.5 to 10% by weight from the viewpoint of printing density and glossiness. 8 wt% is more preferable, and 1 to 5 wt% is particularly preferable.
In the water-based ink, the content of the colorant is preferably 1 to 15% by weight, more preferably 2 to 10% by weight, and particularly preferably 2 to 8% by weight from the viewpoint of printing density.
In the water-based ink, the content of the alkane polyol is preferably 0.2 to 10% by weight, more preferably 0.3 to 8% by weight, and more preferably 0.5 to 5% by weight from the viewpoint of glossiness due to the improvement of stability over time. Is particularly preferred.

The weight ratio of [water-insoluble organic compound / alkane polyol] is preferably from 3/1 to 1/5, more preferably from 1/1 to 1/5, and more preferably from 1/1 to 1/5, from the viewpoint of glossiness due to improved stability over time. 1/3 is particularly preferred.
The weight ratio of [water-insoluble organic compound / polymer particles] is preferably 1/50 to 1/1, more preferably 1/30 to 1/1, and more preferably 1/10 to 1/1, from the viewpoint of improving glossiness. Is particularly preferred.
The weight ratio of [water-insoluble organic compound / colorant] is preferably 1/40 to 5/1, and more preferably 1/30 to 1/1, from the viewpoint of gloss.
The weight ratio of [polymer particles / colorant] is preferably 10/90 to 75/25, more preferably 20/80 to 50/50, from the viewpoints of dispersion stability of polymer particles and printing density.

The water content in the aqueous dispersion and water-based ink of the present invention is preferably 30 to 90% by weight, more preferably 40 to 80% by weight. The water dispersion is obtained by dispersing water as a main medium, and the colorant is dispersed therein. The water-based ink is ink using water as the main medium.
The surface tension (20 ° C.) of the aqueous dispersion of the present invention is preferably 30 to 65 mN / m, more preferably 35 to 60 mN / m. Further, the surface tension (25 ° C.) of the water-based ink is preferably 20 to 35 mN / m, and more preferably 25 to 35 mN / m, from the viewpoint of securing good dischargeability from the ink nozzle.
The viscosity (20 ° C.) of 10% by weight of the aqueous dispersion of the present invention is preferably 2 to 6 mPa · s, and more preferably 2 to 5 mPa · s in order to obtain a preferable viscosity when an aqueous ink is used. In addition, the viscosity (20 ° C.) of the water-based ink of the present invention is preferably 2 to 12 mPa · s, and more preferably 2.5 to 10 mPa · s in order to maintain good ejection properties.

In the following production examples, examples and comparative examples, “parts” and “%” are “parts by weight” and “% by weight” unless otherwise specified. The weight average molecular weight of the polymer was measured by the following method.
(1) Method for measuring weight average molecular weight of polymer Gel chromatography using N, N-dimethylformamide containing 60 mmol / L phosphoric acid and 50 mmol / L lithium bromide as a solvent [GPC apparatus manufactured by Tosoh Corporation (HLC-8120GPC), a column manufactured by Tosoh Corporation (TSK-GEL, α-M × 2), flow rate: 1 mL / min], using polystyrene as a standard substance.

Production Example 1 (Production of polymer)
In a reaction vessel, 20 parts of methyl ethyl ketone, 0.03 part of a polymerization chain transfer agent (2-mercaptoethanol), and 10% of 200 parts of each monomer shown in Table 1 were mixed and thoroughly replaced with nitrogen gas. A mixed solution was obtained.
On the other hand, the remaining 90% of the monomers shown in Table 1 were 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-dimethyl) were added. Valeronitrile)) 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 obtained by dissolving 0.3 part of the radical polymerization initiator 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 method shown above. The results are shown in Table 1.

The details of the compounds shown in Table 1 are as follows.
(B) Styrene macromer, manufactured by Toa Gosei Co., Ltd., trade name: AS-6 (S), number average molecular weight: 6000, polymerizable functional group: methacryloyloxy group (d) PP-800
Polypropylene glycol monomethacrylate (average number of moles of propylene oxide added = 12, terminal: hydroxy group): manufactured by NOF Corporation, trade name: BLEMMER PP-800
(E) 50POEP-800B
Octoxy polyethylene glycol polypropylene glycol monomethacrylate (average added mole number of ethylene oxide = 8, average added mole number of propylene oxide = 6, terminal: 2-ethylhexyl group): manufactured by NOF Corporation, trade name: BLEMMER 50POEP-800B

Synthesis Example 1 (Synthesis of water-insoluble organic compound)
In a reaction vessel, 100 parts of phthalic anhydride, 400 parts of 2-ethylhexyl alcohol ethylene oxide 4 mol adduct (Nippon Emulsifier: New Coal 1004) and 0.5 parts of tetraisopropoxy titanate are mixed and mixed. After sufficient gas replacement, the temperature was raised to 220 ° C. to carry out an esterification reaction. Further, the esterification reaction was completed by carrying out a reduced pressure reaction at 6.67 × 10 ³ Pa at the same temperature, and the excess alcohol was distilled off to obtain a phthalic acid diester-based water-insoluble organic compound A. The SP value of the water-insoluble organic compound A determined from the above Fedors equation was 9.4.

Production Example 2 (Production of aqueous dispersion of polymer particles containing pigment)
25 parts of the polymer obtained by drying the polymer solution obtained in Production Example 1 under reduced pressure was dissolved in 70 parts of methyl ethyl ketone, and 6.7 parts of a neutralizing agent (5N aqueous sodium hydroxide solution) was contained therein (neutralization degree 75%). ) And 230 parts of ion-exchanged water to neutralize the salt-forming groups, and further 75 parts of a diazo pigment (CI Pigment Yellow 74, manufactured by Sanyo Dye Co., Ltd., trade name: FY7413) were added. Using a Picomill (dispersion media: zirconia, temperature: 20 ° C., dispersion media / dispersion weight ratio: 8/2) manufactured by Co., Ltd., dispersion treatment was performed for 2 hours at a peripheral speed of 15 m / s. The obtained mixture was subjected to 10-pass dispersion treatment with a microfluidizer (trade name, manufactured by Microfluidics) at a pressure of 180 MPa.
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: Water of a pigment-containing polymer particle having a solid content concentration of 20% by filtering with a 25 mL needleless syringe (manufactured by Terumo Co., Ltd.) attached with 2.5 cm, manufactured by Fuji Film Co., Ltd., and removing coarse particles. A dispersion was obtained.

Example 1
Manufacture of water dispersion for inkjet recording Production Example 1 80 parts of the aqueous dispersion of the pigment-containing polymer particles obtained and 2 parts of the water-insoluble organic compound A obtained in Synthesis Example 1 were mixed, and an ultrasonic homogenizer US-300T ( Nippon Seiki Seisakusho Co., Ltd.) was used and treated with V-LEVEL 200 μA for 10 minutes to obtain an aqueous dispersion containing water-insoluble organic compound and pigment-containing polymer particles (water-insoluble organic compound-containing aqueous dispersion).

Manufacture of water-based ink for ink jet recording 41 parts of water dispersion containing water-insoluble organic compound, 2 parts of 1,2-hexanediol, 17 parts of glycerin, 2 parts of 2-pyrrolidone, 1 part of triethanolamine, 1 part of triethylene glycol monobutyl ether , Surfinol 104PG50 (manufactured by Nissin Chemical Industry Co., Ltd.) 0.2 part, Olphine E1010 (manufactured by Nissin Chemical Industry Co., Ltd.) 0.6 part and 35.2 parts of ion-exchanged water were mixed, and the resulting mixed liquid Was filtered with a 25 mL needleless syringe equipped with a 1.2 μm filter (acetylcellulose membrane, outer diameter: 2.5 cm, manufactured by Fuji Film Co., Ltd.) to remove coarse particles, thereby obtaining a water-based ink.

Example 2
A water-based ink was obtained in the same manner as in Example 1 except that 1,2-butanediol was used instead of 1,2-hexanediol.
Example 3
A water-based ink was obtained in the same manner as in Example 1 except that 1,2-pentanediol was used instead of 1,2-hexanediol.
Example 4
A water-based ink was obtained in the same manner as in Example 1 except that 1,2-octanediol was used instead of 1,2-hexanediol.
Example 5
A water-based ink was obtained in the same manner as in Example 1 except that 1 part of 1,2-hexanediol and 36.2 parts of ion-exchanged water were used.
Example 6
A water-based ink was obtained in the same manner as in Example 1 except that 3 parts of 1,2-hexanediol and 34.2 parts of ion-exchanged water were used.

Comparative Example 1
A water-based ink was obtained in the same manner as in Example 1 except that 37.2 parts of ion-exchanged water was used without using 1,2-hexanediol.
Comparative Example 2
A water-based ink was obtained in the same manner as in Example 1 except that methyl stearate (SP value 8.6) was used in place of the water-insoluble organic compound A.

Glossiness Evaluation Regarding the water-based inks obtained in Examples 1 to 6 and Comparative Examples 1 and 2, after the production, each of the ink after 1 hour at room temperature and the ink after storage at room temperature for 3 days is a commercially available inkjet printer. (Seiko Epson Co., Ltd., Model: PX-V600, Piezo Method) is used to print solid ink on commercially available inkjet photo paper (trade name: inkjet photo paper <gloss>, Seiko Epson Co., Ltd., trade name: KA450PSK) Printing condition = Paper type: Photo paper <silk-tone>, Mode setting: Photo], left at 25 ° C for 24 hours, then glossiness of 20 ° (Nippon Denshoku Co., Ltd., trade name: HANDY GLOSSMETER) , Product number: PG-1), and the average value was obtained.
The change rate of the glossiness of the ink after storage for 3 days at room temperature with respect to the glossiness of the ink after 1 hour at room temperature was determined by the following formula and expressed as an absolute value.
Gloss change rate (%) = [(Glossiness after storage for 3 days—Glossiness after 1 hour) / Glossiness after 1 hour] × 100

  From Table 2, the aqueous inks of Examples 1 to 6 are excellent in gloss as compared with the aqueous inks of Comparative Examples 1 and 2, and the ink after 1 hour at room temperature and the ink after storage for 3 days at room temperature. It can be seen that there is little change in gloss when printed on special paper, and the stability over time is excellent.

Claims (7)

  A water-insoluble organic compound having a maximum weight of 5 g or less that can be dissolved in 100 g (20 ° C.) of a colorant, polymer particles, and water, and one or more selected from the group consisting of ester compounds, ether compounds, and sulfonic acid amide compounds An aqueous dispersion for ink-jet recording comprising (but not including a fatty acid derivative) and an alkane polyol having 4 to 12 carbon atoms.   The water-insoluble organic compound comprises (f) an ester or ether compound having two or more ester or ether bonds in the molecule, and / or (g) one or more ester or ether bonds in the molecule, An ester or ether compound having at least one functional group selected from the group consisting of a group, a sulfuric acid group, a sulfonic acid group, a phosphonic acid group, a phosphoric acid residue, a carbonyl group, an epoxy group and a hydroxyl group, The aqueous dispersion for inkjet recording according to claim 1.   The aqueous dispersion for inkjet recording according to claim 1 or 2, wherein an absolute value of a difference in solubility parameter (SP value) between the water-insoluble organic compound and the alkane polyol is 6 or less.   The water dispersion for inkjet recording according to any one of claims 1 to 3, wherein a weight ratio of the water-insoluble organic compound to the alkane polyol (water-insoluble organic compound / alkane polyol) is 3/1 to 1/5. .   The aqueous dispersion for inkjet recording according to any one of claims 1 to 4, wherein the alkane polyol is 1,2-alkanediol.   The water dispersion for inkjet recording according to any one of claims 1 to 5, wherein a colorant is contained in the polymer particles.   An aqueous ink for inkjet recording, comprising the aqueous dispersion for inkjet recording according to any one of claims 1 to 6.