JP4810857B2 - Ink composition, ink jet recording method using the same, and recorded matter - Google Patents

Description

  The present invention relates to an ink composition mainly used for printing by an ink jet recording method, an ink jet recording method using the ink composition, and a recorded matter printed by the recording method. More specifically, the present invention is an ink composition that is particularly excellent in color development on glossy paper and glossiness on glossy paper, and is excellent in ejection stability and clogging recovery, an ink jet recording method using the same, And a recorded matter obtained by the method.

The ink jet recording method is a recording method in which ink droplets are ejected from a fine nozzle head and attached to a recording medium such as paper to perform printing.
Conventionally, an ink composition used in an ink jet recording method often uses a water-based dye as a coloring material, and the water-based dye ink can be printed on various recording media and is excellent in recording on glossy paper. Glossiness can be obtained. However, on the other hand, it has the disadvantages of being inferior in light resistance, gas resistance, and water resistance, so recent ink development has been conducted as a colorant to improve the light resistance, gas resistance, and water resistance. Aqueous pigment inks using pigments have also been studied.

The aqueous pigment ink is a dispersion in which pigment fine particles having a certain particle diameter are uniformly dispersed in an aqueous solvent, and after printing on a recording medium, an ink film containing the pigment is formed on the recording medium. Therefore, it is excellent in light resistance, gas resistance and water resistance, and exhibits excellent color developability on various recording media.
On the other hand, when printing is performed on a recording medium having a smooth surface such as glossy paper, there is a problem that the glossiness of the recording portion is impaired due to irregular reflection of light by the pigment fine particles in the ink film. Increasing the pigment content in the ink composition to further improve the color development on plain paper further deteriorates the glossiness, and the viscosity of the ink rapidly increases accordingly, resulting in poor clogging recovery. There was a case.
In addition, in order to disperse the pigment fine particles stably in the ink, an excessive surfactant or polymer dispersant is required, which may cause deterioration of printing stability due to generation of bubbles or wetting. there were.

  On the other hand, if the pigment content in the ink composition is reduced, the glossiness of the recorded part on glossy paper is improved, the ink viscosity is easily controlled to the optimum value, and the clogging recovery is improved, and the pigment fine particles are dispersed. Since the surfactant and the polymer dispersant necessary for the preparation may be in an appropriate amount, the printing stability is improved. However, another problem arises that the color developability on plain paper is reduced.

In response to these problems, for example, Patent Document 1 discloses that by using an aqueous dispersion of water-insoluble vinyl polymer fine particles, an ink composition capable of printing with high color development and excellent gloss can be obtained. Proposed.
However, there are still ink compositions that satisfy all these characteristics, such as excellent color development on plain paper and gloss on glossy paper, as well as excellent ejection stability and clogging recovery, and use of the ink composition. There has been a demand for an ink jet recording method.

JP 2004-75988 A

  The present inventors have solved the problems of the conventional ink composition, for example, when printed by an ink jet recording method, particularly have high colorability on plain paper, excellent gloss on glossy paper, and Another object of the present invention is to provide an ink composition excellent in ejection stability and clogging recovery, an ink jet recording method using the ink composition, and a printed material.

  In order to solve the above-mentioned problems, the present inventors have studied the ink constituents to be added together with the ink colorant, particularly as regards the ink composition using a pigment as the colorant, and as a result, dispersed specific water-insoluble polymer fine particles. The above-described problems can be achieved by using a composition containing a pigment as an agent and two surfactants having a specific composition in a specific weight ratio. On the other hand, the present inventors have obtained knowledge that they have high glossiness and can realize excellent ejection stability and clogging recovery properties.

(1) The ink composition of the present invention comprises a pigment, polymer particles of a water-insoluble vinyl polymer that includes the pigment and enables the pigment to be dispersed in the ink composition, a surfactant, and a main solvent. And the surfactant is a compound represented by the following chemical formula (I) and a compound represented by the following chemical formula (II) at a weight ratio of 5: 7 to 5:13. It is characterized by including in a range.

(2) In the ink composition of the present invention, the water-insoluble vinyl polymer is
A) Formula (III):
Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a hydrogen atom, a phenyl group having an alkyl group having 1 to 20 carbon atoms or an alkyl group having 1 to 9 carbon atoms, m is 1 to 30 A monomer A1 represented by
Formula (IV):
(Wherein, R ¹ and R ² represent the same number of .n 1 to 30 above)
Monomer A2 represented by
Formula (V):
(In the formula, R ¹ , R ² , m and n are the same as above. The oxyethylene group and oxypropylene group may be random or block in [] regardless of their order.)
Monomer A3 represented by the formula (VI):
(Wherein R ¹ , R ² , m and n are the same as described above. The oxypropylene group and oxytetramethylene group may be random or block in [] regardless of their order). Monomer A4 represented
One or more monomers A selected from the group consisting of:
B) a salt-forming group-containing monomer;
C) It is preferable to polymerize a monomer composition containing a monomer copolymerizable with the monomer A and the salt-forming group-containing monomer.

( 3 ) In the ink composition of the present invention, the copolymerizable monomer preferably contains at least one selected from the group consisting of an aromatic ring-containing monomer and a macromer.

( 4 ) In the ink composition of the present invention, the aromatic ring-containing monomer is preferably at least one selected from the group consisting of styrene, α-methylstyrene, vinyltoluene and vinylnaphthalene.

( 5 ) Further, in the ink composition of the present invention, it is preferable that the ink composition further contains a water-soluble organic solvent and / or 1,2-alkanediol.

( 6 ) The inkjet recording method of the present invention is characterized in that droplets of the ink composition of the present invention are ejected from a nozzle and the droplets are adhered to a recording medium.

( 7 ) The recorded matter of the present invention is a recorded matter recorded by the inkjet recording method of the present invention.

  The ink composition of the present invention having the above configuration is excellent in high print quality, high color developability and gloss on glossy paper with respect to plain paper. In addition to being able to obtain printed matter with excellent glossiness, clogging of the printer nozzles is eliminated and discharge stability is ensured.

Hereinafter, the ink composition of the present invention will be described in more detail.
[Ink composition]
The ink composition of the present invention includes [1] a pigment, [2] a polymer particle of a water-insoluble vinyl polymer that includes the pigment and enables the pigment to be dispersed in the ink composition, and [3] a specific ratio. A surfactant containing a compound represented by the following chemical formula (I) and a compound represented by the following chemical formula (II), and [4] water as a main solvent.

Here, n and m in the compound (II) are each an added mole number of an oxyethylene group and an arbitrary number satisfying n + m = 10.

[1] Pigment The pigment used in the ink composition of the present invention may be any of organic pigments and inorganic pigments conventionally used in ink-jet ink compositions. If necessary, extender pigments can be used in combination.
Examples of the organic pigment include azo pigment, diazo pigment, phthalocyanine pigment, quinacridone pigment, isoindolinone pigment, dioxazine pigment, perylene pigment, perinone pigment, thioindigo pigment, anthraquinone pigment, quinophthalone pigment, nitro pigment, nitroso pigment, aniline black Etc.

Specific examples of preferred organic pigments include yellow pigments, C.I. I. Pigment Yellow 74, 93, 109, 110, 128, 138, 150, 151, 154, 155, 180, 185 and the like are preferable, and Pigment Yellow-74 is particularly preferable.
For magenta pigments, C.I. I. Pigment red 122, 202, 209, C.I. I. Pigment Violet 19 and the like are preferable. I. Pigment red 122 and C.I. I. Pigment Violet 19 is preferred.
For cyan pigments, C.I. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 60 and the like are preferable. I. Pigment Blue 15: 3 and 15: 4 are preferred.
Further, as organic pigments used for color inks other than yellow, cyan and magenta, C.I. I. Pigment green 7, 10, 36, 37, C.I. I. Pigment brown 3, 5, 25, 26, C.I. I. Pigment orange 1, 2, 5, 7, 13, 14, 15, 16, 34, 36, 37, C.I. I. Pigment Black 1 or the like can be used.

  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 extender pigments include silica, calcium carbonate, and talc.

[2] Water-insoluble vinyl polymer (polymer) including pigment
The water-insoluble vinyl polymer including the pigment in the ink composition of the present invention (hereinafter also simply referred to as a polymer) is A) the monomer A1 represented by the formula (III) and the monomer A2 represented by the formula (IV). One or more monomers A selected from the group consisting of the monomer A3 represented by the formula (V) and the monomer A4 represented by the formula (VI);
B) a salt-forming group-containing monomer;
C) Monomer composition containing a monomer copolymerizable with the monomer A and the salt-forming group-containing monomer (hereinafter also referred to as copolymerizable monomer)
It is preferable to polymerize.

A) Monomer A
Monomer A is composed of monomer A1 represented by formula (III), monomer A2 represented by formula (IV), monomer A3 represented by (V), and monomer A4 represented by (VI). One or more of the groups are used.
Specific examples of the monomer A1 include polyethylene glycol mono (meth) acrylate.

  Specific examples of the monomer A2 include polypropylene glycol mono (meth) acrylate.

  Specific examples of the monomer A3 include ethylene glycol / propylene glycol (meth) acrylate, poly (ethylene glycol / propylene glycol) mono (meth) acrylate, octoxypolyethylene glycol / polypropylene glycol mono (meth) acrylate, and octoxypoly (ethylene glycol / ethylene glycol). Propylene glycol) mono (meth) acrylate, stearoxy polyethylene glycol / polypropylene glycol mono (meth) acrylate, stearoxy poly (ethylene glycol / propylene glycol) mono (meth) acrylate, nonylphenoxy polyethylene glycol / polypropylene glycol mono (meth) acrylate , Nonylphenoxypoly (ethylene glycol / propylene glycol) mono ( Data) acrylate, and the like. These can be used alone or in admixture of two or more.

  Specific examples of the monomer A4 include propylene glycol / tetramethylene glycol mono (meth) acrylate, poly (propylene glycol / tetramethylene glycol) mono (meth) acrylate, propylene glycol / polybutylene glycol mono (meth) acrylate, and poly (propylene). Glycol / butylene glycol) mono (meth) acrylate and the like. These can be used alone or in admixture of two or more.

  Among the monomers A1 to A4 (monomer A), polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, ethylene glycol / propylene glycol (meth) acrylate and poly (ethylene glycol / propylene glycol) mono (meta) ) Acrylate is preferred from the viewpoints of ink viscosity and dischargeability.

  Examples of the commercially available monomers A1 to A4 include NK esters M-20G, 40G, 90G, and 230G manufactured by Shin-Nakamura Chemical Co., Ltd., Nippon Oil & Fats Co., Ltd. Blemmer PE series, PME-100, 200, 400, 1000, BLEMMER PP-1000, PP-500, PP-800, AP-150, AP-400, AP-550, AP-800, 50PEP-300, 70PEP-350B, AEP series, 30PPT-800, 50PPT-800, 70PPT-800, APT series, 10PPB-500B, 10APB-500B, 50POEP-800B, 50AOEP-800B, ASEP series, PNEP series, PNPE series, 43ANEP-500, 70ANEP-550 and the like.

  Further, the content of the monomer A in the vinyl polymer is preferably 5 to 45% by weight, more preferably 5 to 35% by weight, from the viewpoint of gloss of printed matter and high print density.

B) Salt-forming group-containing monomer As the salt-forming group-containing monomer which is one of the components of the water-insoluble polymer of the present invention, an anionic monomer and a cationic monomer are preferable. Anionic monomers and cationic monomers can be used alone or in admixture of two or more.
Examples of the anionic monomer include one or more selected from the group consisting of an unsaturated carboxylic acid monomer, an unsaturated sulfonic acid monomer, and an unsaturated phosphoric acid monomer. From the viewpoint of ink viscosity and dischargeability, the unsaturated carboxylic acid Monomers are preferred.

  Specific examples of the unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, 2-methacryloyloxymethyl succinic acid, etc., and acrylic acid and methacrylic acid Is more preferable.

  Examples of the cationic monomer include one or more selected from the group consisting of an unsaturated tertiary amine-containing vinyl monomer and an unsaturated ammonium salt-containing vinyl monomer.

  Examples of the unsaturated tertiary amine-containing monomer include N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, and N, N. -Dimethylaminopropyl (meth) acrylamide, N, N-dimethylarylamine, vinylpyrrolidone, 2-vinylpyridine, 4-vinylpyridine, 2-methyl-6-vinylpyridine, 5-ethyl-2-vinylpyridine, etc. It is done. These can be used alone or in admixture of two or more.

  Examples of unsaturated ammonium salt-containing monomers include N, N-dimethylaminoethyl (meth) acrylate quaternized product, N, N-diethylaminoethyl (meth) acrylate quaternized product, N, N-dimethylaminopropyl (meth). Examples include acrylate quaternized products. These can be used alone or in admixture of two or more.

  Among the cationic monomers, N, N-dimethylaminoethyl (meth) acrylate, NN-dimethylaminopropyl (meth) acrylamide and vinyl pyrrolidone are preferable.

  The content of the salt-forming group-containing monomer in the vinyl polymer is 3 to 40% by weight, preferably 5 to 30% by weight, from the viewpoints of dispersion stability and ejection stability.

C) Copolymerizable monomer Examples of the copolymerizable monomer include (meth) acrylic acid esters, aromatic ring-containing monomers, macromers, and the like. These can be used alone or in admixture of two or more. The copolymerizable monomer preferably contains at least one selected from the group consisting of an aromatic ring-containing monomer and a macromer from the viewpoint of water resistance and scratch resistance.

  Examples of (meth) acrylic acid esters include methyl (meth) acrylate, ethyl (meth) acrylate, (iso) propyl (meth) acrylate, (iso or tertiary) butyl (meth) acrylate, (iso) amyl (meta) ) Acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (iso) octyl (meth) acrylate, (iso) decyl (meth) acrylate, (iso) dodecyl (meth) acrylate, (Meth) acrylic acid esters in which the ester moiety such as (iso) stearyl (meth) acrylate is an alkyl group having 1 to 18 carbon atoms are used, and these may be used alone or in combination of two or more. Can do.

  In addition, said (iso or tertiary) and (iso) mean both the case where these groups exist, and the case where it is not so, and when these groups do not exist, it shows normal.

  From the viewpoint of water resistance, the aromatic ring-containing monomer may be styrene, vinylnaphthalene, α-methylstyrene, vinyltoluene, ethylvinylbenzene, 4-vinylbiphenyl, 1,1-diphenylethylene, benzyl (meth) acrylate, phenoxyethyl ( Selected from the group consisting of (meth) acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-methacryloyloxyethyl-2-hydroxypropyl phthalate, 2-acryloyloxyethyl phthalate and neopentyl glycol acrylate benzoate 1 or more types are preferable. Among these, at least one selected from the group consisting of styrene, α-methylstyrene, vinyl toluene, and vinyl naphthalene is more preferable from the viewpoint of water resistance and scratch resistance.

  As a typical example of the macromer, there is a macromer having a polymerizable functional group at one end and preferably having a number average molecular weight of 500 to 500,000, more preferably 1000 to 10,000.

  Specific examples of the macromer include a styrene macromer having a polymerizable functional group at one end, a silicone macromer having a polymerizable functional group at one end, a methyl methacrylate macromer having a polymerizable functional group at one end, Examples thereof include a styrene / acrylonitrile macromer having a polymerizable functional group, a butyl acrylate macromer having a polymerizable functional group at one end, and an isobutyl methacrylate macromer having a polymerizable functional group at one end. Among these, a styrenic macromer having a polymerizable functional group at one end is preferable from the viewpoint of sufficiently containing a colorant in the vinyl polymer.

  Examples of the styrenic macromer having a polymerizable functional group at one end include a styrene homopolymer having a polymerizable functional group at one end and a copolymer of styrene and another monomer having a polymerizable functional group at one end. Can be mentioned.

  In the copolymer of styrene and another monomer having a polymerizable functional group at one end, examples of the other monomer include acrylonitrile. Further, the content of styrene is preferably 60% by weight or more, and more preferably 70% by weight or more from the viewpoint of sufficiently containing the pigment in the vinyl polymer.

  Among the styrenic macromers having a polymerizable functional group at one end, a styrenic macromer having an acryloyloxy group or a methacryloyloxy group as a polymerizable functional group at one end is preferable.

  Examples of commercially available styrenic macromers include AS-6, AS-6S, AN-6, AN-6S, HS-6S, and HS-6 manufactured by Toa Gosei Co., Ltd.

  The copolymerizable monomer content in the vinyl polymer is 15 to 87% by weight, preferably 15 to 75% by weight, from the viewpoint of printing density and water resistance.

  Further, the content of the aromatic ring-containing monomer in the vinyl polymer is preferably 0.1 to 70% by weight, more preferably 1 to 50% by weight, from the viewpoints of water resistance, scratch resistance, ink viscosity and ejection stability. is there.

  The content of the macromer in the vinyl polymer is preferably 0.1 to 40% by weight, more preferably 1 to 30% by weight from the viewpoint of water resistance and scratch resistance.

In the vinyl monomer obtained by polymerizing the above A) monomer A, B) salt-forming group-containing monomer, and C) copolymerizable monomer, the monomer A is present in an amount of 5 to 45% by weight ( Preferably 5 to 35% by weight), salt-forming group-containing monomer 3 to 40% by weight (preferably 5 to 30% by weight), copolymerizable monomer 15 to 87% by weight (preferably 15 to 75% by weight) It is.
The weight average molecular weight of the vinyl polymer is preferably 3,000 to 300,000, more preferably 5,000 to 200,000, from the viewpoints of print density and ejection stability.

(Preparation of polymer particle dispersion containing pigment)
Specifically, the polymer particle dispersion containing the pigment used in the present invention can be prepared by the method described in, for example, JP-A-2001-247810. For example, it can be preferably prepared by the following steps. That is,
(I) A step of preparing a solvent dispersion by mixing the polymer solution dissolved in a water-soluble organic solvent, a pigment, and, if necessary, a neutralizing agent;
(Ii) a phase inversion emulsification step in which the obtained dispersion is developed into an aqueous phase to prepare an aqueous suspension; and (iii) a water-soluble organic solvent added during preparation of the solvent dispersion is distilled off. , Manufactured through a process of including a pigment with polymer particles.

  The neutralizing agent may be appropriately determined. Examples of the alkali include tertiary amines such as trimethylamine and triethylamine, ammonia, sodium hydroxide, potassium hydroxide and the like. As the acid, an inorganic base such as hydrochloric acid or sulfuric acid, or an organic acid such as acetic acid, propionic acid, lactic acid, succinic acid, glycolic acid, gluconic acid or glyceric acid can be used.

  As the organic solvent, water-soluble organic solvents are preferable, alcohols such as methanol, ethanol, and isopropanol, ketones such as acetone, methyl ethyl ketone, diethyl ketone, and methyl isobutyl ketone, and ethers such as dibutyl ether, tetrahydrofuran, and dioxane. It is done.

  In addition, the process of including the pigment in the polymer can use a disperser. Disperse using a disperser such as a ball mill, sand mill, attritor, roll mill, agitator mill, Henschel mixer, colloid mill, ultrasonic homogenizer, jet mill, ang mill, etc. To do. More preferably, a high-pressure homogenizer that is less likely to be mixed with crushed pieces of the dispersion medium is used.

  The particle size of the polymer particles thus obtained is preferably about 25 to 250 nm, more preferably about 30 to 175 nm.

  The weight ratio of these pigments to the polymer containing them is preferably 5:95 to 95: 5, more preferably 10:90 to 90:10. The amount of the pigment added is preferably in the form of being included in the polymer and on the basis of the weight of the pigment alone, preferably 0.5 to 15% by weight, more preferably 1 to 10% by weight based on the total amount of the ink composition. %.

[3] Surfactant The ink composition of the present invention contains at least a compound represented by the chemical formula (I) (hereinafter referred to as “compound (I)”) and a compound represented by the chemical formula (II) (hereinafter referred to as “compound (I)”). , "Compound (II)"). In addition, n and m in the compound (II) are each an added mole number of an oxyethylene group and an arbitrary number satisfying n + m = 10.

In the present invention, when used in combination with the water-insoluble polymer particles, the compound (I) having a low hydrophilic / lipophilic balance (HLB) value and the compound (II) having a high HLB value are used in combination, and the two compounds are in a weight ratio. An ink composition having improved color developability on plain paper, improved clogging recovery, and ejection stability by containing 2: 1 to 1: 4, more preferably 5: 7 to 5:13; can do. The water-insoluble vinyl polymer has a hydrophobic group and a hydrophilic group, is not substantially dissolved in the ink composition, and is in a balance between the hydrophobic group and the hydrophilic group in an aqueous solvent. Is in a distributed equilibrium state. In the ink composition of the present invention, by containing the compound (I) having a low HLB value and the compound (II) having a high HLB value in a specific weight ratio in the ink composition, the equilibrium state thereof is maintained. It is possible to improve color development on plain paper, improve ejection stability, and improve clogging recovery.
Although the total amount of compound (I) and compound (II) may be determined as appropriate, it is preferably 0.03 to 5% by weight, preferably 0.3 to 3% by weight, based on the ink composition. Is more preferable.

  As the compound (I), commercially available products such as Orphine STG (trade name, manufactured by Nissin Chemical) and Surfynol 104 (trade name, manufactured by Air Products and Chemicals Inc.) can be used. As the compound (II), commercially available products such as Surfynol 400 series (trade name, manufactured by Air Products and Chemicals Inc.) and Olphine E1010 (trade name, manufactured by Nissin Chemical Co., Ltd.) can be used.

[4] Water The ink composition of the present invention contains water as a main solvent. As the water, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used. In addition, the use of water sterilized by ultraviolet irradiation or addition of hydrogen peroxide is preferable because generation of mold or bacteria can be prevented when the ink composition is stored for a long period of time.

[5] pH adjuster of ink composition The ink composition according to the present invention preferably further comprises a pH adjuster in terms of improving glossiness on glossy paper. Specific examples of pH adjusters include hydroxides of alkali metals such as lithium hydroxide, potassium hydroxide and sodium hydroxide, amines such as ammonia, triethanolamine, tripropanolamine, diethanolamine and monoethanolamine. Preferred examples include those selected from the group consisting of alkali metal hydroxides, ammonia, triethanolamine, tripropanolamine, and mixtures thereof. The pH of the ink composition is preferably adjusted to 8.0 to 11.0 by adding a pH adjuster. By adjusting the pH of the ink composition within this range, the material constituting the ink jet printer is not adversely affected, the clogging of the recording head of the ink composition can be effectively prevented, and the gloss The gloss on paper can be further improved.

[6] Water-soluble organic solvent The ink composition according to the present invention preferably comprises a water-soluble organic solvent. The water-soluble organic solvent functions mainly as a penetrant, a humectant, a viscosity modifier, etc. for the ink composition. Specific examples of the water-soluble organic solvent include glycerin, 1,2,6-hexanetriol, trimethylolpropane, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, dipropylene glycol, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, 1,2-octanediol, 1,2-hexanediol, 1,2-pentane Polyols such as diol, 4-methyl-1,2-pentanediol, glucose, mannose, fructose, ribose, xylose, arabinose, galactose, aldonic acid, glucitol, sorbitol, maltose, cellobiose, lactose Sugars such as sucrose, trehalose and maltotriose, so-called solid wetting agents such as sugar alcohols, hyaluronic acids and ureas, alkyl alcohols having 1 to 4 carbon atoms such as ethanol, methanol, butanol, propanol and isopropanol, ethylene Glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, ethylene glycol mono-iso-propyl ether, diethylene glycol mono- iso-propyl ether, ethylene glycol mono-n-butyl ether, ethyl Glycol mono-t-butyl ether, diethylene glycol mono-t-butyl ether, 1-methyl-1-methoxybutanol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-t-butyl ether, propylene glycol mono-n-propyl Glycol ethers such as ether, propylene glycol mono-iso-propyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol mono-iso-propyl ether, 2 -Pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, formamide, acetoa De, dimethyl sulfoxide, sorbitol, sorbitan, acetin, diacetin, triacetin, sulfolane, and the like, may be used alone or in combination.

According to a preferred embodiment of the present invention, the ink composition is preferably selected from the group consisting of a water-soluble polyol, glycol-based butyl ether, pyrrolidone and a mixture thereof, more preferably a water-soluble polyol and a glycol-based ink composition. A combination of butyl ether and pyrrolidone is preferred. When this combination is added to the ink composition, it is possible to improve the reliability of the ink composition, such as print quality, ejection stability, and prevention of clogging.
Preferable specific examples of the water-soluble polyol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, 1,3-propylene glycol, isopropylene glycol, isobutylene. Glycol, 1,4-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, glycerin, mesoerythritol, pentaerythritol, thiodiglycol, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, trimethylolethane, trimethylolpropane, pentaerythritol, etc. are mentioned, more preferably, diethylene. Glycol, triethylene glycol, 1,5-pentanediol, glycerin, and trimethylolpropane. Two or more of these may be used in combination.

Preferable specific examples of glycol-based butyl ether include ethylene glycol mono-n-butyl ether, diethylene glycol mono-n-butyl ether, triethylene glycol mono-n-butyl ether, propylene glycol mono-n-butyl ether, or dipropylene glycol mono-n. -Butyl ether etc. are mentioned, More preferably, they are ethylene glycol mono-n-butyl ether and triethylene glycol mono-n-butyl ether. Two or more of these may be used in combination.
Preferable specific examples of pyrrolidone include 2-pyrrolidone and N-methyl-2-pyrrolidone, and 2-pyrrolidone is more preferable. These may be used in combination.
The addition amount of the water-soluble organic solvent is preferably 0.25 to 15% by weight, more preferably 0.5 to 10% by weight, based on the total amount of the ink composition.

[7] 1,2-Alkanediol In the present invention, the ink composition preferably further comprises 1,2-alkanediol.
The 1,2-alkanediol is preferably selected from 1,2-alkanediols having 4 to 10 carbon atoms, more preferably 1,2-hexanediol or 1,2-pentanediol. And more preferably 1,2-hexanediol.
The amount of 1,2-alkanediol added is preferably 0.25 to 15% by weight, more preferably 0.5 to 10% by weight, based on the total amount of the ink composition.

[8] Other components The ink composition according to the present invention may be added with a pH buffer, an antioxidant, an ultraviolet absorber, an antiseptic or antifungal agent, a chelating agent, and the like, if necessary.
Specific examples of the pH buffering agent include collidine, imidazole, phosphoric acid, 3- (N-morpholino) propanesulfonic acid, tris (hydroxymethyl) aminomethane, boric acid and the like.
Specific examples of antioxidants or ultraviolet absorbers include allophanates such as allophanate and methyl allophanate, biurets such as biuret, dimethylbiuret and tetramethylbiuret, L-ascorbic acid and its salts, etc. manufactured by Ciba Geigy Examples include Tinuvin 328, 900, 1130, 384, 292, 123, 144, 622, 770, 292, Irgacor 252, 153, Irganox 1010, 1076, 1035, MD1024, or lanthanide oxides.

  Specific examples of preservatives or fungicides include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazoline-3- ON (Avecia's Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN) and the like. Specific examples of the chelating agent include ethylenediaminetetraacetic acid (EDTA).

(Preparation of ink composition)
The ink composition according to the present invention comprises a polymer particle of a water-insoluble vinyl polymer which includes a predetermined amount of each of the above-described components ([1] pigment, [2] the pigment and disperses the pigment in the ink composition). [3] A surfactant containing the compound represented by the chemical formula (I) and the compound represented by the chemical formula (II), [4] water as a main solvent, and further added thereto as necessary. Are added to a dispersing / mixing machine (for example, a ball mill, a sand mill, an attritor, a basket mill, a roll mill, etc.) and dispersed. According to a preferred embodiment of the present invention, it is preferable to filter the ink stock solution obtained by the dispersing / mixing apparatus using a filter such as a membrane filter or a mesh filter to remove coarse particles.

[Inkjet recording method and recorded matter]
The ink composition of the present invention can be suitably used for writing instruments such as pens, stamps and the like, but can be more suitably used as an ink composition for inkjet recording. In the present invention, the ink jet recording system means a system in which an ink composition is ejected as droplets from a fine nozzle and the droplets are attached to a recording medium. This will be specifically described below.

As a first method, there is an electrostatic suction method, which applies a strong electric field between the nozzle and the acceleration electrode placed in front of the nozzle, and continuously ejects ink from the nozzle in the form of droplets. This is a method in which a print information signal is applied to the deflection electrode while the ink droplet is flying between the deflection electrodes for recording, or a method in which the ink droplet is ejected in response to the print information signal without being deflected.
The second method is a method in which ink droplets are forcibly ejected by applying pressure to the ink liquid with a small pump and mechanically vibrating the nozzle with a crystal resonator or the like. The ejected ink droplet is charged simultaneously with the ejection, and a printing information signal is given to the deflection electrode and recorded while the ink droplet flies between the deflection electrodes.

The third method is a method using a piezoelectric element, in which a pressure and a print information signal are simultaneously applied to an ink liquid by a piezoelectric element to eject and record ink droplets.
The fourth method is a method in which the ink liquid is rapidly expanded in volume by the action of heat energy, and the ink liquid is heated and foamed with a microelectrode in accordance with a print information signal to eject and record ink droplets.
Any of the above methods can be used in the ink jet recording method using the ink of the present invention.

  Further, the recorded matter of the present invention is a recorded matter recorded on a printing medium such as paper by the ink jet recording method of the present invention, and has high color quality and glossiness on glossy paper, and has high print quality. Is obtained.

EXAMPLES Next, although an Example demonstrates this invention, this invention is not restrict | limited to these.
〔Example〕
[Preparation of vinyl polymer]
In a reaction vessel, 20% by weight of methyl ethyl ketone, 0.03 part by weight of 2-mercaptoethanol (polymerization chain transfer agent), and 10% by weight of each monomer amount (parts by weight) shown in Table 1 are added. These were mixed and sufficiently replaced with nitrogen gas to obtain a mixed solution thereof.
Separately, on the other hand, the remaining 90% by weight of the amount (parts by weight) of each monomer shown in Table 1 was charged into the dropping funnel, and then 0.27 wt. Of 2-mercaptoethanol (polymerization chain transfer agent). Part, 60 parts by weight of methyl ethyl ketone and 1.2 parts by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) were mixed and sufficiently substituted with nitrogen gas to obtain a mixed solution.
Under a nitrogen atmosphere, the temperature of the mixed solution in the reaction vessel was increased to 65 ° C. while stirring, and the mixed solution in the dropping funnel was gradually dropped into the reaction vessel over 3 hours. After completion of the dropwise addition, the liquid temperature of the mixed solution was maintained at 65 ° C. for 2 hours, and then a solution in which 0.3 part by weight of 2,2′-azobis (2,4-dimethylvaleronitrile) was dissolved in 5 parts by weight of methyl ethyl ketone was prepared. In addition to the mixed solution, the mixture was further aged at 65 ° C. for 2 hours and 70 ° C. for 2 hours to obtain vinyl polymer 1 and 2 solutions.

  A portion of the resulting polymer solution was isolated by drying at 105 ° C. under reduced pressure for 2 hours and removing the solvent, polystyrene as standard, 60 mmol / L phosphoric acid and 50 mmol / L lithium bromide as solvent. The weight average molecular weight was measured by gel permeation chromatography using dimethylformamide containing. The results are shown in Table 1 together with this vinyl polymer synthesis raw material, its blending ratio, and the degree of neutralization. In addition, the numerical value which shows the compounding ratio of each monomer of Table 1 is a weight part in all except the weight average molecular weight and neutralization degree of a vinyl polymer.

The details of each compound shown in Table 1 are as follows.
(1) Polyethylene glycol monomethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK ester M-230G, a compound in which m is 23 and R ¹ and R ² are methyl groups in the chemical formula (I))
(2) Polypropylene glycol monomethacrylate (Nippon Yushi Co., Ltd., trade name: BLEMMER PP-500, in the above formula (II), n = 9,
R ¹ is a methyl group and R ² is a hydrogen atom)
(3) Poly (ethylene glycol / propylene glycol) monomethacrylate (manufactured by NOF Corporation, trade name: BLEMMER 50PEP-300, in the above formula (III), m is 3.5, n is 2.5, and R1 is A compound in which a methyl group, R2 is a hydrogen atom, and a monomer in which an oxypropylene group and an oxyethylene group are randomly added)
(4) Styrene macromer (manufactured by Toa Gosei Co., Ltd., trade name: AS-6S (styrene macromer), number average molecular weight: 600
0, polymerizable functional group: methacryloyloxy group)

[Preparation of pigment dispersion]
(Preparation of yellow pigment dispersion Y1)
7.5 parts by weight of vinyl polymer 1 in Table 1 is dissolved in 45 parts by weight of methyl ethyl ketone, and a predetermined amount of 20% aqueous sodium hydroxide solution (neutralizing agent) is added to neutralize the salt-forming groups, As a pigment, C.I. I. 20 parts by weight of Pigment Yellow 74 was added and kneaded in a bead mill for 2 hours.
After 120 parts by weight of ion-exchanged water was added to the kneaded product thus obtained and stirred, methyl ethyl ketone was removed at 60 ° C. under reduced pressure, and a part of the water was further removed to obtain a solid content concentration of 20%. A weight% pigment dispersion Y1 was obtained.

(Preparation of magenta pigment dispersion M1)
5 parts by weight, not 7.5 parts by weight, of vinyl polymer 1 in Table 1 was dissolved in 45 parts by weight of methyl ethyl ketone, and 20 parts by weight of C.I. I. In place of Pigment Yellow 74, 20 parts by weight of C.I. I. A pigment dispersion M1 having a solid content concentration of 20% by weight was obtained in the same manner as the yellow pigment dispersion Y1 except that CI Pigment Violet 19 was used.

(Preparation of cyan pigment dispersion C1)
12.5 parts by weight of the vinyl polymer of Table 1 is used instead of 7.5 parts by weight, and 20 parts by weight of C.I. I. In place of Pigment Yellow 74, 12.5 parts by weight of C.I. I. A cyan pigment dispersion C1 having a solid concentration of 20% by weight was obtained in the same manner as the yellow pigment dispersion except that CI Pigment Blue 15: 4 was used.

(Preparation of yellow pigment dispersion Y2, magenta pigment dispersion M2 and cyan pigment dispersion C1)
A yellow pigment dispersion Y2 having a solid content concentration of 20% by weight was obtained in the same manner as the yellow pigment dispersion Y1 except that the vinyl polymer 2 was used in place of the vinyl polymer 1 shown in Table 1.
A magenta pigment dispersion M2 was obtained in the same manner as the magenta pigment dispersion M1 except that the vinyl polymer 2 was used instead of the vinyl polymer 1 shown in Table 1.
Further, a cyan pigment dispersion C2 was obtained in the same manner as the cyan pigment dispersion C1 except that the vinyl polymer 2 was used instead of the vinyl polymer 1 shown in Table 1.

[Preparation of ink composition]
Each pigment dispersion (Y1, Y2, M1, M2, C1, and C2) prepared as described above, each solvent, and ultrapure water were mixed at a blending ratio (% by weight) shown in Table 2 below. And stirred for 2 hours. Subsequently, the mixture was filtered using a membrane filter (trade name, manufactured by Nippon Millipore Limited) having a pore diameter of about 8 μm to prepare ink compositions of Examples 1 to 10 and Comparative Examples 1 to 5.

[Evaluation of ink composition]
About each obtained ink composition of Examples 1-10 and Comparative Examples 1-5, each following test was done and the characteristic was evaluated. The results are shown in Table 3 below.
Evaluation 1: Print density test The print density was evaluated by using a inkjet printer PX-G900 (trade name, manufactured by Seiko Epson Corp.), printing a single color solid on Xerox 4024 at 720 dpi x 720 dpi and leaving at 25 ° C for 24 hours. Thereafter, the printing density on the recording surface was measured by using Spectrolino (trade name, manufactured by Grekda Macbeth). A value obtained by taking an average of five measurement values for each recording paper was calculated and evaluated according to the following criteria.
A: Print density is 1.2 or more.
B: The print density is 1.1 or more and less than 1.2.
C: Print density is 1.0 or more and less than 1.1.

Evaluation 2: Glossiness test Using the printer, a monochromatic solid print was made at 1440 dpi × 720 dpi on photo paper <Glossy> (trade name, manufactured by Seiko Epson), left at 25 ° C. for 24 hours, and an incident angle of 20 degrees. The specular glossiness of the recording surface was measured by using a gloss meter GM-268 (trade name, manufactured by Konica Minolta Sensing). A value obtained by averaging five times for each recording paper was calculated and evaluated according to the following criteria.
A: Specular gloss is 60 or more.
B: Specular gloss is 55 or more and less than 60.
C: Specular gloss is 50 or more and less than 55.
D: Specular gloss is less than 50.

Evaluation 3: Ejection stability test Using an ink jet printer PX-A550 (trade name, manufactured by Seiko Epson Corporation), the obtained ink composition is filled in an ink cartridge, and mounted on the printer and continuously printed for 10 minutes. After confirming that all nozzles discharged normally, continuous printing was performed on the same photographic paper <glossy> as described above for a long time in an environment at a temperature of 40 ° C. About each ink composition, the dot missing at the time of printing and the presence or absence of ink scattering were observed, and the ejection stability was evaluated according to the following criteria.
The weight of ink ejected per dot was 30 ng, and the resolution was 360 dpi × 360 dpi.
A: No dot dropout or ink scattering occurs even after 4 hours.
B: After 3 hours, the occurrence of missing dots or ink scattering was confirmed.
C: After 2 hours, dot missing or ink splattering was confirmed.
D: Occurrence of missing dots or ink scattering occurred within 1 hour.

Evaluation 4: Clogging recovery test Using the printer PX-A550, the ink composition obtained was filled into an ink cartridge, mounted on the printer, printed continuously for 10 minutes, and all nozzles discharged normally. After confirming that this was done, the printer was stopped, the ink cartridge was removed from the printer, and left for 1 week in an environment of 40 ° C. without a cap. After leaving, an ink cartridge filled with the same ink composition was mounted, and the cleaning operation was repeated until all nozzles ejected in the same manner as before leaving, and clogging recovery was evaluated according to the following criteria.
A: All nozzles were recovered by 0 to 2 cleanings.
B: All nozzles recovered after 3 to 5 cleanings.
C: All nozzles could not be recovered after 6 cleanings.

  As can be seen from Table 3, the ink composition of the present invention (the ink compositions of Examples 1 to 10) has excellent characteristics for all evaluation items of print density, glossiness, ejection stability and clogging recovery properties. It can be seen that

  The water-based ink of the present invention is excellent in high color development on plain paper and glossiness on glossy paper when printing or drawing is recorded on the substrate, and also excellent in ejection stability and clogging recovery of the printer head. It is suitably used as a printer ink for printing by an inkjet recording method or the like.

Claims (7)

Comprising at least a pigment, a polymer particle of a water-insoluble vinyl polymer containing the pigment and capable of dispersing the pigment in the ink composition, a surfactant, and water as a main solvent. An ink composition comprising an activator containing a compound represented by the following chemical formula (I) and a compound represented by the following chemical formula (II) in a weight ratio of 5: 7 to 5:13 . .
The water-insoluble vinyl polymer is A) Formula (III):
Wherein R ¹ is a hydrogen atom or a methyl group, R ² is a hydrogen atom, a phenyl group having an alkyl group having 1 to 20 carbon atoms or an alkyl group having 1 to 9 carbon atoms, m is 1 to 30 A monomer A1 represented by
Formula (IV):
(Wherein, R ¹ and R ² represent the same number of .n 1 to 30 above)
Monomer A2 represented by
Formula (V):
(In the formula, R ¹ , R ² , m and n are the same as above. The oxyethylene group and oxypropylene group may be random or block in [] regardless of their order.)
Monomer A3 represented by the formula (VI):
(In the formula, R ¹ , R ² , m and n are the same as described above. The oxypropylene group and the oxytetramethylene group may be random or block in any order within [].)
Monomer A4 represented by
One or more monomers A selected from the group consisting of:
B) a salt-forming group-containing monomer;
2. The ink composition according to claim 1, wherein a monomer composition containing a monomer copolymerizable with the monomer A and the salt-forming group-containing monomer is polymerized.
The ink composition according to claim 2 , wherein the copolymerizable monomer contains at least one selected from the group consisting of an aromatic ring-containing monomer and a macromer. The ink composition according to claim 3 , wherein the aromatic ring-containing monomer is at least one selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, and vinylnaphthalene. The ink composition according to any one of claims 1 to 4 , wherein the ink composition further contains a water-soluble organic solvent and / or 1,2-alkanediol. An ink jet recording method characterized by claim droplets ejected from the nozzles of the ink composition according to any one of clauses 1-5, depositing the droplets onto a recording medium. A recorded matter recorded by the ink jet recording method according to claim 6 .