JP2002249684A - Inks and their uses - Google Patents

Abstract

[PROBLEMS] To provide an ink-jet ink and an ink composition which are less affected by contamination by an ionic substance and hardly cause nozzle clogging even during long-term storage and high-temperature storage. SOLUTION: General formula 1 [X is a divalent organic residue, Y is an alkyleneoxy group of C1 -C6, Z is H or ^{R 5 -O- (C = O)} - (R 5
Is a C1-C10 alkyl or hydroxyalkyl group. ) R ¹ is H or a methyl group, R ^{2 to} R ⁴ are the same or different and H or a C1 to C6 alkyl or hydroxyalkyl group, m is an integer of 0 to 20, and n is an integer of 1 to 4. An ink containing a phosphorylcholine-like group-containing polymer having the structural unit of the above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink, and more particularly to an ink-jet ink using a pigment or a water-insoluble dye as a colorant.

[0002]

2. Description of the Related Art In the field of ink jet printing, water-soluble dyes have conventionally been used as colorants for inks, but recently, research and development using pigments having excellent light resistance as dyes for inks have been conducted. Is being actively conducted. When a pigment is compounded as an ink, a technique for stably dispersing the pigment in an aqueous medium is required in order to maintain the ejection properties and dispersion stability of the ink. In the fields of paint and printing other than ink jet, a large amount of dispersant can be blended for dispersing the pigment, so that the dispersibility of the pigment is not a problem. However, in the case of inkjet inks, the viscosity of the ink must be set low and fluidity must be ensured, so that the dispersant cannot be blended at a high concentration and the dispersibility of the pigment in the ink is low. .

[0003] In order to solve the above problems, pigment dispersants for ink-jet inks have been developed. There are two types of raw materials, ionic and non-ionic dispersants. . In the case of an ionic dispersant, for example, a carboxylic acid, a sulfonic acid, a dispersant represented by a water-soluble polymer having a phosphoric acid component,
In these dispersants, aggregation of particles is prevented by electrostatic repulsion to stabilize the dispersion, and therefore, the dispersibility tends to decrease due to contamination by other ionic substances and fluctuation in pH. In the case of nonionic, for example, surfactants having a nonionic hydrophilic component such as polyethylene glycol and polyvinyl alcohol, dispersants represented by water-soluble polymers such as ethyl cellulose, and the like. In order to stabilize the dispersion by the three-dimensional excluded volume effect of the hydrated hydrophilic component, the hydrophilic component is contained in a high composition, and the water resistance after printing is low. In order to solve the above problems, further improvements have been made as pigment dispersants for inkjet. JP-A-2000-95987 discloses an ink-jet ink in which a hydrophilic vinyl monomer is directly covalently bonded to the surface of pigment particles to improve dispersibility. Is complicated.

Japanese Patent Application Laid-Open No. 10-195362 discloses an ink jet ink using a fluoroalkyl group-containing emulsion polymer.
Since it is manufactured using a delicate two-phase emulsification system, it is difficult to obtain an emulsion polymer having a stable dispersion performance without lot fluctuation. Also, Japanese Patent Application Laid-Open No. 8-295837
The publication discloses a method of improving the dispersibility by encapsulating a pigment in urethane-based fine particles, but it involves a complicated urethane-forming reaction while dispersing an organic phase in which a polyurethane raw material and a pigment are dissolved in an organic solvent in an aqueous system. And the complicated manufacturing process, the particle size distribution of the fine particles is apt to fluctuate depending on the dispersion state of the organic phase, and the urethanization reaction is easily affected by water. JP-A-10-87754 discloses a graft polymer having a water-soluble main chain composed of an acid component and a hydrophobic graft chain as a pigment dispersant for an inkjet ink. Since the dispersibility is not sufficient, the dispersibility is not high, and the dispersibility tends to decrease due to contamination by other ionic substances and the influence of pH. As described above, an ink-jet ink composition characterized by a dispersant has been developed.However, it is not sufficient to maintain the dispersion stability of the pigment for a long period of time. It is easy to cause nozzle clogging. Further, even in the case of a conventional inkjet ink using a water-soluble dye, the dye precipitates due to the effects of long-term storage, high-temperature storage, contamination by an ionic substance, and the like, and the nozzle is likely to be clogged by aggregation.

On the other hand, a phosphorylcholine-like group-containing polymer is excellent in biocompatibility such as blood compatibility, deactivation of complement, and non-adsorption of biological substances due to a phospholipid-like structure derived from a biological membrane. It is also known to have excellent properties such as antifouling properties and moisturizing properties. Active research and development on the synthesis of polymers for the purpose of developing bio-related materials utilizing their respective functions and their uses are being actively conducted. Have been done.

[0006] Japanese Patent Application Laid-Open No. 10-109092 discloses that a polymer having a phosphorylcholine-like group-containing polymer which is difficult to dissolve or disperse in water can be solubilized.
Techniques that can be applied in the field of cosmetics and the like are disclosed.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ink composition having good dispersibility of a pigment as a dye. Another object of the present invention is to provide an inkjet ink and an ink composition which are less affected by ionic substance contamination and are less likely to cause nozzle clogging even during long-term storage and high-temperature storage.

[0008]

Means for Solving the Problems The present invention provides the following [1]-
This is shown in [5]. [1] The following equation (1)

[0009]

Embedded image

[In the formula, X represents a divalent organic residue, Y represents an alkyleneoxy group having 1 to 6 carbon atoms, Z represents a hydrogen atom or R ⁵ -O- (C = O)-(provided that R ⁵ represents an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 10 carbon atoms.). R ¹ represents a hydrogen atom or a methyl group, and R ² , R ³ and R ⁴ are the same or different groups and represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group. m shows the integer of 0-20. n shows the integer of 1-4. ] The ink contains a phosphorylcholine analog-containing monomer represented by the formula: [2] The polymer having a phosphorylcholine-like group is represented by the following formula (2)

[0011]

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Wherein X represents a divalent organic residue, Y represents an alkyleneoxy group having 1 to 6 carbon atoms, and Z represents a hydrogen atom or R ⁵ —O— (C = O) — (provided that R ⁵ represents an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 10 carbon atoms.). R ¹ represents a hydrogen atom or a methyl group, and R ² , R ³ and R ⁴ are the same or different groups and represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group. m shows the integer of 0-20. n shows the integer of 1-4. Is an ink obtained by polymerizing a monomer composition containing a phosphorylcholine-like group-containing monomer represented by the formula: [3] An ink containing the phosphorylcholine-like group-containing polymer containing 10 to 95% by weight of the structural unit represented by the formula (1) and having a weight average molecular weight in the range of 1,000 to 1,000,000. [4] An ink that is an ink jet ink. [5] An inkjet ink composition comprising the following components A, B, C and D. Component A: phosphorylcholine analog-containing polymer 0.1 to 5
Component B: 1 to 60% by weight of an organic solvent selected from alcohols, ketones and esters; Component D: 25 to 98% by weight of water.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The phosphorylcholine analog-containing polymer used in the present invention has the following formula (1)

[0014]

Embedded image

[Wherein, X represents a divalent organic residue, Y represents an alkyleneoxy group having 1 to 6 carbon atoms, and Z represents a hydrogen atom or R ⁵ -O- (C = O)-(provided that R ⁵ represents an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 10 carbon atoms.). R ¹ represents a hydrogen atom or a methyl group, and R ² , R ³ and R ⁴ are the same or different groups and represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group. m shows the integer of 0-20. n shows the integer of 1-4. ] It is a polymer containing the structural unit represented by these.

The phosphorylcholine analog-containing monomer used in the present invention is represented by the following formula (2):

[0017]

Embedded image

[In the formula, X represents a divalent organic residue, Y represents an alkyleneoxy group having 1 to 6 carbon atoms, and Z represents a hydrogen atom or R ⁵ -O- (C = O)-(provided that R ⁵ represents an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 10 carbon atoms.). R ¹ represents a hydrogen atom or a methyl group, and R ² , R ³ and R ⁴ are the same or different groups and represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group. m shows the integer of 0-20. n shows the integer of 1-4. ].

R ^{1 in the} formulas (1) and (2) represents a hydrogen atom or a methyl group. R ² , R ³ and R ^{4 in the} formulas (1) and (2) are the same or different groups and represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group having 1 to 6 carbon atoms, Specifically, for example, carbon number 1
Examples of the alkyl group having 6 to 6 include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group. Examples of the hydroxyalkyl group having 1 to 6 carbon atoms include a hydroxymethyl group and a 2-hydroxyethyl group. A 3-hydroxypropyl group, a 2-hydroxypropyl group, a 4-hydroxybutyl group, a 2-hydroxybutyl group, a 5-hydroxypentyl group, a 2-hydroxypentyl group, a 6-hydroxyhexyl group, a 2-hydroxyhexyl group, and the like. No.

In the formulas (1) and (2), X represents a divalent organic residue.
A divalent organic residue such as -C₆H_Four−,
−C₆H_Ten-,-(C = O) O-, -O-, -CH_Two−O−, − (C = O)
 NH-, -O- (C = O)-, -O- (C = O) -O-, -C₆H_Four−O
−, −C₆H_Four−CH_Two−O−, −C₆H _Four-(C = O) O- and the like
And preferably-(C = O) O-.

In the formulas (1) and (2), Y has 1 to 6 carbon atoms.
Specific examples include a methyloxy group, an ethyloxy group, a propyloxy group, a trimethyleneoxy group, a tetramethyleneoxy group, a butyloxy group, a pentyloxy group, and a hexyloxy group. Is an ethyloxy group.

Z in the formulas (1) and (2) is a hydrogen atom or a group represented by R ⁵ —O— (C = O) —. Here, R ⁵ is an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 10 carbon atoms include a methyl group, an ethyl group, a propyl group,
Examples include a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, and a decyl group. Carbon number 1
Examples of the hydroxyalkyl group of 10 to 10 include a hydroxymethyl group, a 2-hydroxyethyl group, a 3-hydroxypropyl group, a 2-hydroxypropyl group, a 4-hydroxybutyl group, a 2-hydroxybutyl group, a 5-hydroxypentyl group, 2-hydroxypentyl, 6-hydroxyhexyl, 2-hydroxyhexyl, 7-hydroxyheptyl, 2-hydroxyheptyl, 8-hydroxyoctyl, 2-hydroxyoctyl, 9-
Hydroxynonyl group, 2-hydroxynonyl group, 10-
Examples include a hydroxydecyl group and a 2-hydroxydecyl group. Most preferably, Z in the formulas (1) and (2) is a hydrogen atom from the viewpoint of polymerizability. M in the formulas (1) and (2) represents a number from 0 to 20, and is preferably 1. N in the formulas (1) and (2) represents an integer of 1 to 4,
Preferably it is 2.

The phosphorylcholine analog-containing monomer is, for example, 2- (methacryloyloxy) ethyl-2'-
(Trimethylammonio) ethyl phosphate, 3-
(Methacryloyloxy) propyl-2 '-(trimethylammonio) ethyl phosphate, 4- (methacryloyloxy) butyl-2'-(trimethylammonio)
Ethyl phosphate, 5- (methacryloyloxy) pentyl-2 '-(trimethylammonio) ethyl phosphate, 6- (methacryloyloxy) hexyl-2'
-(Trimethylammonio) ethyl phosphate, 2-
(Methacryloyloxy) ethyl-2 '-(triethylammonio) ethyl phosphate, 2- (methacryloyloxy) ethyl-2'-(tripropylammonio)
Ethyl phosphate, 2- (methacryloyloxy) ethyl-2 '-(tributylammonio) ethyl phosphate, 2- (methacryloyloxy) ethyl-2'-
(Tricyclohexylammonio) ethyl phosphate, 2- (methacryloyloxy) ethyl-2 ′-(triphenylammonio) ethylphosphate, 2- (methacryloyloxy) ethyl-2 ′-(trimethanolammonio) ethylphosphate, 2 -(Methacryloyloxy) propyl-2 '-(trimethylammonio)
Ethyl phosphate, 2- (methacryloyloxy) butyl-2 '-(trimethylammonio) ethyl phosphate, 2- (methacryloyloxy) pentyl-2'-
(Trimethylammonio) ethyl phosphate, 2-
(Methacryloyloxy) hexyl-2 '-(trimethylammonio) ethyl phosphate, 2- (vinyloxy) ethyl-2'-(trimethylammonio) ethyl phosphate, 2- (allyloxy) ethyl-2 '-(trimethylammonio) Ethyl phosphate, 2- (p-
Vinylbenzyloxy) ethyl-2 '-(trimethylammonio) ethylphosphate, 2- (p-vinylbenzoyloxy) ethyl-2'-(trimethylammonio) ethylphosphate, 2- (styryloxy) ethyl-2'- (Trimethylammonio) ethyl phosphate, 2- (p-vinylbenzyl) ethyl-2 ′-(trimethylammonio) ethylphosphate, 2- (vinyloxycarbonyl) ethyl-2 ′-(trimethylammonio) ethylphosphate, 2 -(Allyloxycarbonyl) ethyl-2 '-(trimethylammonio) ethyl phosphate, 2- (acryloylamino) ethyl-
2 ′-(trimethylammonio) ethyl phosphate,
2- (vinylcarbonylamino) ethyl-2 '-(trimethylammonio) ethyl phosphate, ethyl-
(2′-trimethylammonioethyl phosphorylethyl) fumarate, butyl- (2′-trimethylammonioethyl phosphorylethyl) fumarate, hydroxyethyl- (2′-trimethylammonioethyl phosphorylethyl) fumarate, ethyl- (2′-) Trimethylammonioethylphosphorylethyl) malate, butyl-
(2'-trimethylammonioethyl phosphorylethyl) malate, hydroxyethyl- (2'-trimethylammonioethyl phosphorylethyl) malate and the like can be mentioned.

Among these, 2- (methacryloyloxy) ethyl-2 '-(trimethylammonio) ethyl phosphate (hereinafter sometimes abbreviated as MPC) is more preferred from the viewpoint of availability and effects.

When using the phosphorylcholine-like group-containing monomer, it can be used alone or as a mixture.

Phosphorylcholine-like group-containing monomers are disclosed in JP-A-54-63025 and JP-A-58-15459.
It can be produced by a method in which a phosphate ester group and a choline group are sequentially added to 2-hydroxyethyl methacrylate according to a known method described in, for example, Japanese Patent Application Laid-Open Publication No. 1 (1999) -175.

In the polymerization, a phosphorylcholine group-containing monomer and another copolymerizable monomer may be mixed, and specific examples of the other polymerizable monomer include, for example,
Methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate , Cyclohexyl (meth) acrylate, polypropylene glycol mono (meth) acrylate, polytetramethylenethylene glycol mono (meth) acrylate, polypropylene glycol di (meth) acrylate, polytetramethylenethylene glycol di (meth) acrylate, polypropylene glycol polyethylene glycol mono (Meth) acrylate, glycidyl (meth) acrylate, (meth) acryloyloxypropyltrimethoxysilane, Len, methyl styrene, chloromethyl styrene, methyl vinyl ether, butyl vinyl ether, vinyl acetate, vinyl propionate 2-hydroxyethyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, (meth ) Acrylic acid, styrenesulfonic acid, (meth) acrylamide, (meth) acryloyloxyphosphonic acid, aminoethyl methacrylate, dimethylaminoethyl (meth) acrylate, 2-
Examples thereof include hydroxy-3- (meth) acryloxypropyltrimethylammonium chloride and polyethylene glycol mono (meth) acrylate.

The phosphorylcholine-like group-containing polymer (hereinafter abbreviated as PC polymer) in the present invention is obtained by polymerizing the phosphorylcholine-like group-containing monomer (hereinafter abbreviated as PC monomer) alone. , PC monomer and the copolymerizable monomer.

The weight average molecular weight of the PC polymer is 1,000
The range is preferably from 0 to 1,000,000, more preferably from 3,000 to 100,000, and still more preferably from 5,000 to 30,000. If the weight average molecular weight is less than 1,000, it is difficult to sufficiently exhibit pigment dispersibility. If the weight average molecular weight is more than 1,000,000, the viscosity of the ink containing the PC polymer becomes too high, and the ejection property of the ink becomes high. Is undesirably reduced.

The coloring agent of the ink-jet ink in the present invention is mainly a pigment or a water-insoluble dye, but a water-soluble dye is also applicable. As the pigment, either an inorganic pigment or an organic pigment can be used, but an organic pigment having a low specific gravity is desirable.

Specific types of pigments include, for example,
Examples of black pigments include carbon black and graphite, and examples of white pigments include titanium oxide, phosphate, molybdate, and zinc oxide.
Phthalocyanine blue, Indathrone blue and the like, and as the red pigment, red iron oxide, copper oxide, monoazo red, polyazo red, perylene maroon, quinacdrine magenta, lake red and the like, and as the yellow pigment, graphite, iron oxide yellow Quinophthaline yellow, benzimidazolone yellow, monoazo yellow, polyazo yellow, isoindoline yellow, etc., and green pigments include chromium oxide, brominated copper phthalocyanine green, etc., and orange pigments are benzimidazolone. Orange, disazo orange and the like.

The particle size of the pigment particles is preferably in the range of 10 nm to 5 μm, more preferably 30 nm to 1 μm. 1
If it is less than 0 nm, the cohesiveness is too strong and it is difficult to sufficiently stabilize the dispersion, and if it is more than 5 μm, it tends to be clogged with a nozzle for ejecting ink, which is not preferable.

In the ink-jet ink of the present invention, it is desirable to adjust the volatility, viscosity and specific gravity of the ink by using at least one organic solvent selected from alcohols, ketones and esters.

Examples of the organic solvent include, for example, methanol, ethanol, propanol, butanol, ethylene glycol, propylene glycol, butylene glycol, methoxyethanol, diethylene glycol, dipropylene glycol phenyl ether, diethylene glycol, glycerin, pentaerythritol Alcohols such as acetone, methyl ethyl ketone,
Ketones such as diethyl ketone and N-methylpyrrolidone;
Esters such as ethyl acetate and propyl acetate are exemplified. These solvents may be used alone or in combination of two or more.

If necessary, an organic solvent other than an organic solvent selected from alcohols, ketones and esters may be added to the ink-jet ink composition of the present invention as long as the effects of the present invention are not impaired. Alternatively, ions, conductivity adjusters, pH adjusters, chelating agents, viscosity adjusters, wetting agents, surfactants, antibacterial agents and the like may be added.

As a method for preparing the ink composition for inkjet of the present invention, for example, a PC polymer is dissolved in water or an organic solvent, a pigment is added thereto, and a shaker, a homogenizer, a microfluidizer, a roll mill, an ultrasonic wave Dispersion may be performed by an apparatus or method such as irradiation, and then, if necessary, dilution may be performed. Further, the method can also be carried out by adding and mixing a PC polymer to the pigment and then dispersing the pigment in water or an organic solvent.

The ink-jet ink composition of the present invention contains the PC polymer in the range of 0.1 to 5% by weight, more preferably 0.5 to 3% by weight, and contains the colorant in the range of 0.5 to 3% by weight.
15% by weight, more preferably 1 to 5% by weight, and 1 to 60% by weight, more preferably 5 to 40% by weight of an organic solvent selected from alcohols, ketones and esters, and 25 to 98% of water. % By weight, more preferably 40-95
It is a composition containing in the range of% by weight.

When the content of the PC polymer is less than 0.1% by weight, the effect of improving the ink ejection property cannot be sufficiently exhibited, and when it is more than 5% by weight, the viscosity of the ink increases. It is not preferable because it becomes difficult to handle.

When the content of the coloring agent is less than 0.5% by weight, it is difficult to sufficiently color the ink. When the content is more than 15% by weight, the pigment is liable to aggregate when the ink is ejected, which is not preferable.

When the content of the organic solvent is less than 1% by weight, the effect of adjusting the volatility, viscosity and specific gravity of the ink is small.
It is not preferable because the pigment dispersing effect cannot be exhibited.

[0041]

Since the ink of the present invention contains a specific PC group-containing polymer, it is an ink excellent in dispersibility of pigments and the like. In addition, the ink-jet ink of the present invention is suitable for use without any nozzle clogging at the time of use.

[0042]

Now, the present invention will be described in further detail with reference to specific examples. 1. Polymer molecular weight analysis method Methanol / chloroform / lithium bromide (60 /
40 / 0.15) as an eluent, detection is carried out by gel permeation chromatography (GPC), polyethylene glycol standard, UV (260 nm) and refractive index. 2. Ink evaluation method The test ink composition was allowed to stand at 70 ° C. for 4 days, shaken gently, and filled with the test ink in a black ink bottle of an EPSON inkjet printer, and characters were continuously printed. 50 sheets of 50 characters × 50 lines are printed on one sheet of plain paper for copying. The evaluation is made based on the frequency of blurring of characters (including abnormalities such as blurring and large amounts of ink adhesion) and the number of sheets on which printing stops due to clogging of nozzles. Comprehensive evaluation,
The evaluation was performed according to the following evaluation criteria. ◎: No nozzle clogging, no faint characters were generated, ○: No nozzle clogging, but slight fading characters (less than 3 fading characters / sheet), △: No nozzle clogging, Those with a blurred character (three or more blurred characters / sheet), ×: Those with clogged nozzles and many blurred characters.

Synthesis Example 1 Synthesis of Polymer 1 MPC; 17.7 g, stearyl methacrylate (C18
MA); 2.3 g of isopropanol; dissolved in 380 g of isopropanol, placed in a four-necked flask, and blown with nitrogen for 30 minutes.
At 0 ° C., 0.41 g of azobisisobutyronitrile was added and polymerization was carried out for 8 hours.
Concentrated to 0 g. This solution was added dropwise to 1.5 L of diethyl ether while stirring, and the deposited precipitate was filtered and collected.
Vacuum drying was performed for 8 hours at room temperature to obtain 16.6 g of powder. The weight average molecular weight evaluated by GPC is 27,00
It was 0. This is designated as polymer 1. Polymer 1 to M
Abbreviated as PC0.9-C18MA0.1.

Synthesis Examples 2 to 8: Synthesis of Polymers 2 to 8
I got For Synthesis Examples 4 to 7, 100 g of the solution after the polymerization reaction was taken out and added dropwise to diethyl ether.
g, and the same treatment as in Synthesis Example 1 was performed except that 50 g of ethanol was added, and the resulting mixture was dropped into diethyl ether. Table 1 also shows the analysis results of the polymer.

[0045]

[Table 1]

Example 1 Blue pigment FASTGEN BLUE 5380 I. B-15: 3
15 g was added to a mixed solution of 50 g of ethylene glycol and 25 g of N-methylpyrrolidone, and the mixture was thoroughly stirred and coarsely dispersed. In this dispersion,
A solution prepared by dissolving 10 g of Polymer 1 in 400 g of pure water was added, and the mixture was dispersed with a homogenizer while irradiating ultrasonic waves. After that, the mixture was filtered with a 1.6 μm filter and emulsified under pressure with a microfluidizer. This solution was added to a 0.45 pore size
The solution was filtered through a μm membrane filter to obtain a test ink composition. The ink was tested according to the evaluation method described above. Table 2 shows the results.
No fading characters occurred.

Examples 2 to 16, Comparative Examples 1 to 6 As shown in Table 2, the types of the polymer and the dispersing agent are shown in Table 2. The molecular weight of the polymer, the polymer concentration, the solvent type, the presence or absence of salt addition (model of ionic contamination), etc. The test was performed in the same manner as in Example 1 except that the printing state of the ink composition was examined. Table 2 shows the results.

[0048]

[Table 2]

The abbreviations used in the table are as follows. Dispersant 1: polyethylene glycol nonyl phenyl ether (product name: Nonion NS-230, manufactured by NOF Corporation) Dispersant 2: polyethylene glycol polypropylene glycol block copolymer (product name: PRONON 204, manufactured by NOF Corporation), dispersant 3 A styrene-maleic acid-based polymer surfactant (manufactured by NOF Corporation, product name: Marialim AKM-053)
1) Dispersant 4: carboxylic acid-based polymer surfactant (manufactured by NOF Corporation, product name: Polystar OM).

As described above, from the comparison of the results of Examples 1 to 16 of the present invention and Comparative Examples 1 to 6 using different dispersants, the ink composition and the inkjet ink of the present invention have good pigment dispersibility. Further, it is found that the long-term storage property and the high-temperature storage property are good, and the nozzle clogging can be improved even in the case of ion contamination (salt addition).

 ──────────────────────────────────────────────────続 き Continued on front page F-term (reference) 2C056 EA14 FC01 2H086 BA52 BA53 BA59 BA62 4J027 AA02 AC02 AC03 AC04 AJ01 BA05 BA07 BA09 BA10 BA12 BA14 BA19 CA12 CA14 CA28 CA34 CB09 CD08 4J039 AD08 AD23 BC07 BC10 BC11 BC18 BE22 BE01 BE18 CA02 CA03 EA41 EA44 GA24 4J100 AB07P AE09P AE18P AL08P AL82P AM21P BA02P BA04P BA08P BA12P BA15P BA32P BA65P CA01 CA04 DA01 EA06 JA07

Claims (5)

[Claims] (1) The following formula (1): [Wherein, X represents a divalent organic residue, Y represents an alkyleneoxy group having 1 to 6 carbon atoms, Z represents a hydrogen atom or R ⁵ -O
— (C = O) — (where R ⁵ represents an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 10 carbon atoms). R ¹ represents a hydrogen atom or a methyl group,
R ² , R ³ and R ⁴ are the same or different groups and represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms or a hydroxyalkyl group. m shows the integer of 0-20. n is 1
Shows an integer of ~ 4. An ink comprising a phosphorylcholine-like group-containing polymer having a structural unit represented by the formula: 2. The polymer having a phosphorylcholine-like group is represented by the following formula (2): [Wherein, X represents a divalent organic residue, Y represents an alkyleneoxy group having 1 to 6 carbon atoms, Z represents a hydrogen atom or R ⁵ -O
— (C = O) — (where R ⁵ represents an alkyl group having 1 to 10 carbon atoms or a hydroxyalkyl group having 1 to 10 carbon atoms). R ¹ represents a hydrogen atom or a methyl group,
R ^2, R ³ and R ⁴ are the same or different groups, a hydrogen atom or an alkyl or hydroxyalkyl group having 1 to 6 carbon atoms. m shows the integer of 0-20. n is 1
Shows an integer of ~ 4. The ink according to claim 1, which is a polymer having a structural unit based on a phosphorylcholine analog-containing monomer represented by the formula: 3. A polymer containing a phosphorylcholine-like group containing 10 to 95% by weight of a structural unit represented by the formula (1), and having a weight average molecular weight in a range of 1,000 to 1,000,000. 3. The ink according to 1 or 2. 4. The ink according to claim 1, wherein the ink is an ink jet ink. 5. An ink-jet ink composition comprising the following components A, B, C and D. Component A: 0.1 to 5% by weight of the phosphorylcholine-like group-containing polymer according to any one of claims 1 to 3, Component B: 0.5 to 15% by weight of a coloring agent, Component C; selected from alcohols, ketones and esters. 1 to 60% by weight of one or more organic solvents obtained; D component; 25 to 98% by weight of water.