JP2019157108A - Ink, ink cartridge, image forming method, and printed matter - Google Patents

Abstract

To provide an ink which has high storage stability and exhibits high image density even when dried by heating.SOLUTION: The ink comprises water, a coloring material, and a cross-linked material comprising a structural unit represented by the general formulas (1) and (2) in the figure. In the general formula (1), X represents a hydrogen atom or a cation, and R1 represents a hydrogen atom or a methyl group. In the general formula (2), R2 represents a hydrogen atom or a methyl group, and L represents an alkylene group having 2 to 18 carbon atoms.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ink, an ink cartridge, an image forming method, and a printed matter.

The inkjet recording method is popular because it has the advantage that the process is simple and full color can be easily achieved compared to other recording methods, and a high-resolution image can be obtained even with an apparatus with a simple configuration. It is expanding from personal to office use, commercial printing and industrial printing. In such an ink jet recording method, a water-based ink composition using a water-soluble dye as a coloring material is mainly used. However, since it has a disadvantage of being inferior in water resistance and light resistance, it is a water-insoluble alternative to a water-soluble dye. Development of pigment inks using these pigments is underway.
In inkjet printing for office use, plain paper is mainly used as a recording medium, and high image density is required. In general, when pigment ink is printed on plain paper, the pigment penetrates into the paper without staying on the paper surface, so the pigment density on the paper surface is lowered and the image density is lowered. If the pigment concentration in the ink is increased, the image density is increased, but the viscosity of the ink is increased and the ejection stability is lowered.
In the field of commercial printing and industrial printing, there is a need for a technique for stably creating an image with higher resolution and sharpness at a higher speed. As the recording medium, plain paper, coated paper, art paper, non-permeable film such as PET film, and the like are used, and high adaptability of the ink to the recording medium is required. Inkjet recording system prevents paper curling that occurs when printing on plain paper, or when printing on coated paper or art paper, increases ink permeability, speeds drying and prevents beading For this purpose, there is a method of adding a hydrophilic organic solvent to the water-based ink. Beading is a phenomenon in which image quality is impaired due to the occurrence of irregular gaps, increased density, and the like because adjacent dots are connected on a recording sheet.

In addition, the aqueous pigment ink used in the ink jet recording method and writing instrument is different from the aqueous dye ink prepared by dissolving the dye in water, because it is necessary to stably disperse the pigment insoluble in water for a long period of time. Various pigment dispersants have been developed. For example, a graft polymer containing an aromatic ring in the side chain has been proposed (see, for example, Patent Document 1).
Patent Document 2 proposes a method using a copolymer having a naphthyl group. By this method, an ink having excellent ink storage stability, image density, and beading resistance is provided.

However, the ink using the copolymer described in Patent Document 2 has a risk of lowering the image density when the printed image is heated and dried.
Accordingly, an object of the present invention is to provide an ink capable of obtaining a high image density even when heat drying is performed.

The problem is solved by the following configuration 1).
An ink containing water, a coloring material, and a crosslinked product having a structural unit represented by the following general formulas (1) and (2).

  However, in the said General formula (1), X is a hydrogen atom or a cation, R1 represents a hydrogen atom or a methyl group, R2 is a hydrogen atom or a methyl group in General formula (2), L Represents an alkylene group having 2 to 18 carbon atoms. * Is a bond.

  According to the present invention, it is possible to provide an ink capable of obtaining a high image density even when heat drying is performed.

FIG. 1 is an explanatory perspective view illustrating an example of an ink jet recording apparatus. FIG. 2 is an explanatory perspective view showing an example of a main tank in the ink jet recording apparatus.

(ink)
The ink of the present invention contains water, a color material, and a crosslinked product having a structural unit represented by the following general formulas (1) and (2). As a specific embodiment, water, color, A material, a structural unit represented by the following general formulas (1) and (2), and a copolymer having a crosslinked structure by a crosslinking agent are contained. Hereinafter, the present invention will be described by taking the embodiment as an example.

  However, in the said General formula (1), X is a hydrogen atom or a cation, R1 represents a hydrogen atom or a methyl group, R2 is a hydrogen atom or a methyl group in General formula (2), L Represents an alkylene group having 2 to 18 carbon atoms. * Is a bond.

<Structural Unit Represented by General Formula (1)>

  Specific examples of the structural unit represented by the general formula (1) are given below, but the present invention is not limited to the following specific examples.

In the general formula (I), X is a hydrogen atom or a cation, and in the case of a cation, oxygen adjacent to the cation exists as O ⁻ . As cations, sodium ion, potassium ion, lithium ion, tetramethylammonium ion, tetraethylammonium ion, tetrapropylammonium ion, tetrabutylammonium ion, tetrapentylammonium ion, tetrahexylammonium ion, triethylmethylammonium ion, tributylmethyl Ammonium ion, trioctylmethylammonium ion, 2-hydroxyethyltrimethylammonium ion, tris (2-hydroxyethyl) methylammonium ion, propyltrimethylammonium ion, hexyltrimethylammonium ion, octyltrimethylammonium ion, nonyltrimethylammonium ion, decyltrimethyl Ammonium ion Dodecyl trimethyl ammonium ion, tetradecyl trimethyl ammonium ion, hexadecyl trimethyl ammonium ion, octadecyl trimethyl ammonium ion, didodecyl dimethyl ammonium ion, ditetradecyl dimethyl ammonium ion, dihexadecyl dimethyl ammonium ion, dioctadecyl dimethyl ammonium ion, ethyl hexa Decyl dimethyl ammonium ion, ammonium ion, dimethyl ammonium ion, trimethyl ammonium ion, monoethyl ammonium ion, diethyl ammonium ion, triethyl ammonium ion, monoethanol ammonium ion, diethanol ammonium ion, triethanol ammonium ion, methyl ethanol ammonium ion Ion, methyldiethanolammonium ion, dimethylethanolammonium ion, monopropanolammonium ion, dipropanolammonium ion, tripropanolammonium ion, isopropanolammonium ion, morpholinium ion, N-methylmorpholinium ion, N-methyl-2- Examples include pyrrolidonium ions and 2-pyrrolidonium ions.

The structural unit represented by the general formula (1) is formed by copolymerizing a monomer having an anionic group. Examples of the monomer having an anionic group include unsaturated carboxylic acid monomers, unsaturated sulfonic acid monomers, and unsaturated phosphoric acid monomers.
Examples of the unsaturated carboxylic acid monomer include acrylic acid, methacrylic acid, itaconic acid, maleic acid, and fumaric acid. Examples of the unsaturated sulfonic acid monomer include styrene sulfonic acid and 2-acrylamido-2-methylpropane sulfonic acid. Examples of unsaturated phosphoric acid monomers include vinylphosphonic acid, vinyl phosphate, bis (methacryloxyethyl) phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, dibutyl-2-acrylic acid. And leuoxyethyl phosphate.
Among these, from the viewpoint of storage stability, a monomer having a carboxyl group is preferable, and acrylic acid or methacrylic acid is more preferable.

You may use the monomer which has the said anionic group individually or in mixture of 2 or more types.
The structural unit having an anionic group may be neutralized with a base.
Examples of the base include sodium hydroxide, potassium hydroxide, lithium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, tetrapentylammonium hydroxide, tetrahexylammonium hydroxide. , Triethylmethylammonium hydroxide, tributylmethylammonium hydroxide, trioctylmethylammonium hydroxide, 2-hydroxyethyltrimethylammonium hydroxide, tris (2-hydroxyethyl) methylammonium hydroxide, propyltrimethylammonium hydroxide, hexyltrimethylammonium Hydroxide, octyltrimethylammonium hydride Xoxide, nonyltrimethylammonium hydroxide, decyltrimethylammonium hydroxide, dodecyltrimethylammonium hydroxide, tetradecyltrimethylammonium hydroxide, hexadecyltrimethylammonium hydroxide, octadecyltrimethylammonium hydroxide, didodecyldimethylammonium hydroxide, ditetradecyl Dimethylammonium hydroxide, dihexadecyldimethylammonium hydroxide, dioctadecyldimethylammonium hydroxide, ethylhexadecyldimethylammonium hydroxide, aqueous ammonia, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoethanolamine, diethanolamine, Examples include ethanolamine, methylethanolamine, methyldiethanolamine, dimethylethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, isopropanolamine, morpholine, N-methylmorphone, N-methyl-2-pyrrolidone, and 2-pyrrolidone. .
You may use the base as a neutralizing agent individually or in mixture of 2 or more types.
The neutralization treatment may be performed when the monomer having an anionic group is copolymerized or may be performed when the copolymer is dissolved.

<Structural Unit Represented by General Formula (2)>
In the general formula (2), R2 represents a hydrogen atom or a methyl group, and L represents an alkylene group having 2 to 18 carbon atoms. If possible, the alkylene group having 2 to 18 carbon atoms may be independently substituted with a methyl group, an ethyl group, a propyl group, or a butyl group. L is preferably an alkylene group having 2 to 16 carbon atoms, and more preferably an alkylene group having 2 to 6 carbon atoms.
Specific examples of the structural unit represented by the general formula (2) are listed below, but the present invention is not limited to the following specific examples.

In the structural unit represented by the general formula (2), one end of the naphthyl group present at the terminal end via an alkylene group in the open end (open end, in other words, pendant structure) is a coloring material in the ink. It has excellent pigment adsorbing power due to π-π stacking with a pigment.
As can be understood from the description of the “naphthyl group present at the terminal via the alkylene group in the pendant”, the structural unit represented by the general formula (2) is typically suspended via the alkylene group. It may be a main chain of a copolymer having a pendant group such as a terminal naphthyl group. However, as a matter of course, the case where a part is included in the side chain is not excluded.
For example, it is a well-known fact that it is difficult to completely eliminate secondary radical polymerization reactions that produce branched structures.
Further, when preparing the pigment dispersion in which the pigment is dispersed in water, if the copolymer used in the present invention is used, a naphthyl group is present at the end of the side chain of the copolymer, so that the pigment surface Since it is easily adsorbed and has a high adsorbing power with the pigment, a highly dispersible long-term stable pigment dispersion can be obtained.

<Composition ratio of copolymer>
The molar ratio between the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2) is represented by the general formula (1) :( 2) = 0 from the viewpoint of the ability to adsorb the pigment. .1: 1 to 10: 1, preferably 0.3: 1 to 5: 1, more preferably 0.5: 1 to 3: 1. When the entire copolymer is 100% by mass, the total mass ratio of the structural units represented by the general formula (1) and the general formula (2) is 37 to 98% by weight, preferably 54 to 95% by weight, More preferably, it is 66 to 92% by weight.

<Molecular weight of copolymer>
The weight average molecular weight of the copolymer in the present invention is preferably 5000 to 50000, more preferably 5000 to 40000, and particularly preferably 15000 to 40000 in terms of polystyrene. When the weight average molecular weight is within a preferred range, it is advantageous in that the image density and storage stability are improved when used in ink.

<Other monomers>
The copolymer in the present invention may have a structural unit composed of another polymerizable monomer in addition to the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2). .
The other polymerizable monomer is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a polymerizable hydrophobic monomer, a polymerizable hydrophilic monomer, and a polymerizable surfactant.
Examples of the polymerizable hydrophobic monomer include unsaturated ethylene monomers having an aromatic ring such as styrene, α-methylstyrene, 4-t-butylstyrene, 4-chloromethylstyrene; methyl (meth) acrylate, (Meth) ethyl acrylate, (n-butyl) (meth) acrylate, dimethyl maleate, dimethyl itaconate, dimethyl fumarate, lauryl (meth) acrylate (C12), tridecyl (meth) acrylate (C13), ( Tetradecyl (meth) acrylate (C14), pentadecyl (meth) acrylate (C15), hexadecyl (meth) acrylate (C16), heptadecyl (meth) acrylate (C17), nonadecyl (meth) acrylate (C19), Eicosyl acrylate (C20), helicosyl (meth) acrylate ( 21), alkyl (meth) acrylates such as docosyl (meth) acrylate (C22); 1-heptene, 3,3-dimethyl-1-pentene, 4,4-dimethyl-1-pentene, 3-methyl-1 -Hexene, 4-methyl-1-hexene, 5-methyl-1-hexene, 1-octene, 3,3-dimethyl-1-hexene, 3,4-dimethyl-1-hexene, 4,4-dimethyl-1 -Hexene, 1-nonene, 3,5,5-trimethyl-1-hexene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene , Unsaturated ethylene monomers having an alkyl group such as 1-octadecene, 1-nonadecene, 1-eicocene and 1-docosene. These may be used individually by 1 type and may use 2 or more types together.
Examples of the polymerizable hydrophilic monomer include (meth) acrylic acid-2-hydroxyethyl, diethylene glycol mono (meth) acrylate, triethylene glycol mono (meth) acrylate, tetraethylene glycol mono (meth) acrylate, and polyethylene glycol. Mono (meth) acrylate, (meth) acrylamide, N-methylol (meth) acrylamide, N-vinylformamide, N-vinylacetamide, N-vinylpyrrolidone, acrylamide, N, N-dimethylacrylamide, Nt-butylacrylamide, Nonionic unsaturated ethylene monomers such as N-octylacrylamide and Nt-octylacrylamide are exemplified.

  The polymerizable hydrophobic monomer and the polymerizable hydrophilic monomer are mixed in one kind or two or more kinds, the structural unit represented by the general formula (1) and the structure represented by the general formula (2). It can be used in an amount of 5 to 100% by weight based on the total amount of monomers forming the unit.

The polymerizable surfactant is an anionic or nonionic surfactant having at least one unsaturated double bond group capable of radical polymerization in the molecule.
Examples of the anionic surfactant, ammonium sulfate base ^_(-SO 3 - _NH ^{4 +)} hydrocarbon compound having a sulfate group and an allyl group _{(-CH 2} -CH = CH 2), such as, ammonium sulfate base (-SO ₃ ^- NH ₄ ⁺⁾ sulfate group and methacrylic group, such as _{[-CO-C (CH 3) =} CH 2 ] a hydrocarbon compound having, or ammonium sulfate base ^_(-SO 3 - _NH ^{4 +)} sulfate, such as base and 1 An aromatic hydrocarbon compound having a —propenyl group (—CH═CH ₂ CH ₃ ) and the like can be mentioned.
As the anionic surfactant, commercially available products can be used. Examples of the commercially available products include Eleminol JS-20 and RS-300 manufactured by Sanyo Chemical Industries, Ltd .; Aqualon manufactured by Daiichi Kogyo Seiyaku Co., Ltd. KH-10, Aqualon KH-1025, Aqualon KH-05, Aqualon HS-10, Aqualon HS-1025, Aqualon BC-0515, Aqualon BC-10, Aqualon BC-1025, Aqualon BC-20, Aqualon BC-2020, etc. Can be mentioned.

Examples of the nonionic surfactant include a hydrocarbon compound having a 1-propenyl group (—CH═CH ₂ CH ₃ ) and a polyoxyethylene group [— (C ₂ H ₄ O) n—H], or An aromatic hydrocarbon compound etc. are mentioned. Commercially available products of the nonionic surfactant include, for example, Aqualon RN-20, Aqualon RN-2025, Aqualon RN-30, Aqualon RN-50, manufactured by Daiichi Kogyo Seiyaku Co., Ltd .; Latemul PD, manufactured by Kao Corporation -104, Latem PD-420, Latem PD-430, Latem PD-450 and the like.

  The polymerizable surfactant is a mixture of one or more kinds, and the total amount of monomers that form the structural unit represented by the general formula (1) and the structural unit represented by the general formula (2). In contrast, 0.1 to 10% by weight can be used.

<Crosslinking agent>
The crosslinking agent in the present invention is not particularly limited and can be appropriately selected depending on the purpose. However, two or more epoxy groups are contained in the molecule from the viewpoint that a high image density can be obtained even when heat drying is performed. The case where the crosslinking agent which is a compound which has is especially preferable. Examples of the crosslinking agent that is a compound having two or more epoxy groups in the molecule include ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, and resorcinol diglycidyl ether. Neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, dibromoneopentyl glycol diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, terephthalic acid diglycidyl ester, phthalic acid diglycidyl ester. Examples thereof include hydrogenated phthalic acid diglycidyl ester sorbitol polyglycidyl ether, glycerol polyglycidyl ether, diglycerol polyglycidyl ether, polyglycerol glycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol glycidyl ether, and cresol novolac type epoxy emulsion.

<Synthesis Method of Copolymer>
The copolymer in the present invention can be obtained by copolymerizing monomers represented by the following general formulas (3) and (4) in the presence of a radical polymerization initiator and then reacting with a crosslinking agent.

In the general formula (3), X is a hydrogen atom or a cation, R ₁ represents a hydrogen atom or a methyl group, in general formula (4), R 2 is a hydrogen atom or a methyl group, and Y is An alkylene group having 2 to 18 carbon atoms is represented.

  Specific examples of the monomer represented by the general formula (4) are given below, but the present invention is not limited to the following specific examples.

  The monomer represented by the general formula (4) can be synthesized and used as follows. That is, as shown in the following reaction formula, naphthalenecarbonyl chloride (A-1) and an excess amount of a diol compound (L in the following reaction formula represents an alkylene group) are present in the presence of an acid acceptor such as amine or pyridine. Under the condensation reaction, naphthalenecarboxylic acid hydroxyalkyl ester (A-2) is obtained. Next, the monomer (A-4) represented by the general formula (4) can be obtained by reacting the isocyanate compound (A-3) with the (A-2).

As a method for synthesizing the copolymer in the present invention, a method using a radical polymerization initiator is preferable because the polymerization operation and the molecular weight are easily adjusted, and a solution polymerization method in which a polymerization reaction is performed in a solution is more preferable.
Preferred solvents for radical polymerization by the solution polymerization method include ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, acetate solvents such as ethyl acetate and butyl acetate, and aromatic carbonization such as benzene, toluene and xylene. Examples thereof include hydrogen solvents, isopropanol, ethanol, cyclohexane, tetrahydrofuran, dimethylformamide, dimethyl sulfoxide, hexamethylphosphoamide, and the like, and ketone solvents, acetate solvents, and alcohol solvents are more preferable.

  There is no restriction | limiting in particular as said radical polymerization initiator, According to the objective, it can select suitably. Examples thereof include peroxyketals, hydroperoxides, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, peroxy esters, cyano azobisisobutyronitrile, azobis (2-methylbutyronitrile), Examples thereof include azobis (2,2′-isovaleronitrile), non-cyano dimethyl-2,2′-azobisisobutyrate, and the like. Among these, organic peroxides and azo compounds are preferable, and azo compounds are particularly preferable because the molecular weight is easily controlled and the decomposition temperature is low.

  There is no restriction | limiting in particular in content of the said radical polymerization initiator, Although it can select suitably according to the objective, 1-10 mass% is preferable with respect to the total amount of a polymerizable monomer.

In order to adjust the molecular weight of the copolymer, an appropriate amount of a chain transfer agent may be added.
Examples of the chain transfer agent include mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 2-mercaptoethanol, thiophenol, dodecyl mercaptan, 1-dodecanethiol, thioglycerol, and the like.

There is no restriction | limiting in particular in content of the said crosslinking agent, Although it can select suitably according to the objective, It is preferable that content of the copolymer of a crosslinking agent is 0.1-10 mass%. Here, the content of the crosslinking agent represents the content of the crosslinking agent remaining in the copolymer after the crosslinking reaction between the copolymer and the crosslinking agent.
The polymerization temperature and the reaction temperature with the crosslinking agent are not particularly limited and may be appropriately selected depending on the intended purpose. The polymerization time is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 3 to 48 hours.

<Amount of copolymer added>
The content of the copolymer of the present invention in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. However, the solid content is preferably 0.05% by mass to 10% by mass, 0.1% The mass% is more preferably 10% by mass, and particularly preferably 0.3% by mass to 5% by mass.
When the content is 0.05% by mass or more, the effect of improving the pigment dispersibility and the storage stability of the ink is good, and when the content is 10% by mass or less, it is suitable for discharging ink from the head. Viscosity range.

The copolymer of the present invention is not particularly limited, and can be used as a pigment dispersant or an additive to the pigment dispersion. When used as a pigment dispersant, further improvement in storage stability in inks having a high water-soluble organic solvent content is observed.
The content of the copolymer of the present invention is not particularly limited when used as a pigment dispersant, and can be appropriately selected according to the purpose. And 1 mass part-100 mass parts are preferable with respect to 100 mass parts of said pigments, and 5 mass parts-80 mass parts are more preferable. When the content is within the more preferable range, it is advantageous in that image density and storage stability are improved.

<Water>
As said water, pure water, such as ion-exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water can be used, for example.
The content of the water in the ink is not particularly limited and may be appropriately selected according to the purpose. However, from the viewpoint of ink drying property and ejection reliability, it is preferably 10% by mass or more and 90% by mass or less, 20 mass% or more and 60 mass% or less are more preferable.

<Color material>
As the color material, a pigment or a dye can be used. The pigment is preferable from the viewpoints of the pigment being superior to the dye in terms of the ability of the copolymer to adsorb to the coloring material, and water resistance and light resistance.
There is no restriction | limiting in particular as said pigment, According to the objective, it can select suitably, For example, the inorganic pigment, organic pigment, etc. for black or color are mentioned. These may be used alone or in combination of two or more.

  Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, and chrome yellow, as well as a known method such as a contact method, a furnace method, and a thermal method. Carbon black can be used.

  Examples of black pigments include, for example, carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, and metals such as copper and iron (CI pigment black 11). And metal pigments such as titanium oxide, and organic pigments such as aniline black (CI Pigment Black 1).

The carbon black is a carbon black produced by a furnace method or a channel method, a primary particle size of 15 nm to 40 nm, a specific surface area by a BET method of 50 m ² / g to 300 m ² / g, and a DBP oil absorption of 40 mL. / 100 g to 150 mL / 100 g, those having a volatile content of 0.5% to 10% and a pH of 2 to 9 are preferred.

Examples of the organic pigment include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, Dioxazine pigments, indigo pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye chelate, acid dye chelate, etc.), nitro pigments, nitroso pigments, aniline black, and the like can be used.
Of these pigments, those having a good affinity for water are particularly preferably used.

  Examples of the azo pigments include azo lakes, insoluble azo pigments, condensed azo pigments, and chelate azo pigments.

  Examples of the polycyclic pigment include a phthalocyanine pigment, a perylene pigment, a perinone pigment, an anthraquinone pigment, a quinacridone pigment, a dioxazine pigment, an indigo pigment, a thioindigo pigment, an isoindolinone pigment, a quinofullerone pigment, and a rhodamine B lake pigment. .

  Examples of the dye chelate include basic dye chelate and acid dye chelate.

  There is no restriction | limiting in particular as a pigment for yellow, According to the objective, it can select suitably, For example, C.I. I. Pigment yellow 1, C.I. I. Pigment yellow 2, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 12, C.I. I. Pigment yellow 13, C.I. I. Pigment yellow 14, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 73, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 75, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 95, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 98, C.I. I. Pigment yellow 114, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 128, C.I. I. Pigment yellow 129, C.I. I. Pigment yellow 138, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment yellow 174, C.I. I. And CI Pigment Yellow 180.

  The magenta pigment is not particularly limited and may be appropriately selected depending on the intended purpose. I. Pigment red 5, C.I. I. Pigment red 7, C.I. I. Pigment red 12, C.I. I. Pigment red 48 (Ca), C.I. I. Pigment red 48 (Mn), C.I. I. Pigment red 57 (Ca), C.I. I. Pigment red 57: 1, C.I. I. Pigment red 112, C.I. I. Pigment red 122, C.I. I. Pigment red 123, C.I. I. Pigment red 146, C.I. I. Pigment red 168, C.I. I. Pigment red 176, C.I. I. Pigment red 184, C.I. I. Pigment red 185, C.I. I. Pigment Red 202, Pigment Violet 19 and the like.

  The pigment for cyan is not particularly limited and may be appropriately selected depending on the intended purpose. I. Pigment blue 1, C.I. I. Pigment blue 2, C.I. I. Pigment blue 3, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15:34, C.I. I. Pigment blue 16, C.I. I. Pigment blue 22, C.I. I. Pigment blue 60, C.I. I. Pigment blue 63, C.I. I. Pigment blue 66; C.I. I. Bat Blue 4, C.I. I. Examples include Bat Blue 60.

  In addition, C.I. I. Pigment Yellow 74, C.I. I. Pigment red 122, C.I. I. Pigment Bio Red 19 and C.I. I. By using CI Pigment Blue 15: 3, a well-balanced ink having excellent color tone and light resistance can be obtained.

  For the ink of the present invention, a color material newly produced for the present invention can also be used.

Further, from the viewpoint of color developability of the obtained image, a self-dispersing pigment may be used, and an anionic self-dispersing pigment is preferable. The anionic self-dispersing pigment refers to a pigment that is dispersed and stabilized by introducing an anionic functional group directly on the pigment surface or via another atomic group.
As the pigment before dispersion stabilization, for example, various conventionally known pigments as listed in International Publication No. 2009/014242 can be used.
In addition, an anionic functional group means the functional group which half or more of hydrogen ions dissociate at pH 7.0. Specific examples of the anionic functional group include a carboxyl group, a sulfo group, and a phosphonic acid group. Among these, a carboxyl group or a phosphonic acid group is preferable from the viewpoint of increasing the optical density of the obtained image.
Examples of the method for introducing an anionic functional group into the surface of the pigment include a method for oxidizing carbon black.
Specific examples of the oxidation treatment method include a method of treating with hypochlorite, ozone water, hydrogen peroxide, chlorite, nitric acid, etc., Patent No. 3808504, Special Table 2009-515007, And a surface treatment method using a diazonium salt as described in JP-A-2009-506196.
Examples of commercially available pigments having a hydrophilic functional group introduced on the surface include CW-1, CW-2, and CW-3 (above, manufactured by Orient Chemical Industry Co., Ltd.); CAB-O-JET200, CAB- O-JET300, CAB-O-JET400 (manufactured by Cabot Corporation) and the like can be mentioned.

  The content of the pigment in the ink is not particularly limited and may be appropriately selected depending on the intended purpose. More preferred.

  As the dye, dyes classified in the color index into acid dyes, direct dyes, basic dyes, reactive dyes, and food dyes can be used.

  Examples of the acid dyes and food dyes include C.I. I. Acid Black 1, 2, 7, 24, 26, 94, C.I. I. Acid Yellow 17, 23, 42, 44, 79, 142, C.I. I. Acid Blue 9, 29, 45, 92, 249, C.I. I. Acid Red 1, 8, 13, 14, 18, 26, 27, 35, 37, 42, 52, 82, 87, 89, 92, 97, 106, 111, 114, 115, 134, 186, 249, 254, 289, C.I. I. Food Black 1, 2, C.I. I. Food Yellow 3, 4, C.I. I. Food red 7, 9, 14 etc. are mentioned.

  Examples of the direct dye include C.I. I. Direct Black 19, 22, 32, 38, 51, 56, 71, 74, 75, 77, 154, (168), 171, C.I. I. Direct Yellow 1, 12, 24, 26, 33, 44, 50, 86, 120, 132, 142, 144, C.I. I. Direct Blue 1, 2, 6, 15, 22, 25, 71, 76, 79, 86, 87, 90, 98, 163, 165, 199, 202, C.I. I. Direct Red 1, 4, 9, 13, 17, 20, 28, 31, 39, 80, 81, 83, 89, 225, 227, C.I. I. Direct orange 26, 29, 62, 102 etc. are mentioned.

  Examples of the basic dye include C.I. I. Basic Black 2, 8, C.I. I. Basic yellow 1, 2, 11, 13, 14, 15, 19, 21, 23, 24, 25, 28, 29, 32, 36, 40, 41, 45, 49, 51, 53, 63, 64, 65, 67, 70, 73, 77, 87, 91, C.I. I. Basic Blue 1, 3, 5, 7, 9, 21, 22, 26, 35, 41, 45, 47, 54, 62, 65, 66, 67, 69, 75, 77, 78, 89, 92, 93, 105, 117, 120, 122, 124, 129, 137, 141, 147, 155, C.I. I. Basic Red 2, 12, 13, 14, 15, 18, 22, 23, 24, 27, 29, 35, 36, 38, 39, 46, 49, 51, 52, 54, 59, 68, 69, 70, 73, 78, 82, 102, 104, 109, 112 and the like.

  Examples of the reactive dye include C.I. I. Reactive Black 3, 4, 7, 11, 12, 17, C.I. I. Reactive Yellow 1, 5, 11, 13, 14, 20, 21, 22, 25, 40, 47, 51, 55, 65, 67, C.I. I. Reactive Blue 1, 2, 7, 14, 15, 23, 32, 35, 38, 41, 63, 80, 95, C.I. I. Reactive Red 1, 14, 17, 25, 26, 32, 37, 44, 46, 55, 60, 66, 74, 79, 96, 97, etc. are mentioned.

  The ink of the present invention is an organic solvent for increasing the permeability to plain paper, coated paper, etc., further suppressing the occurrence of beading, and for preventing the ink from drying by utilizing the wetting effect. It is preferable to contain.

<Organic solvent>
The organic solvent used in the present invention is not particularly limited, and a water-soluble organic solvent can be used. Examples thereof include ethers such as polyhydric alcohols, polyhydric alcohol alkyl ethers and polyhydric alcohol aryl ethers, nitrogen-containing heterocyclic compounds, amides, amines and sulfur-containing compounds.

  Specific examples of the water-soluble organic solvent include, for example, ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,4-butane. Diol, 2,3-butanediol, 3-methyl-1,3-butanediol, triethylene glycol, polyethylene glycol, polypropylene glycol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol 2,4-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,3-hexanediol, 2,5-hexanediol, 1,5-hexanediol, Glycerin, 1,2,6-hexanetriol, 2-ethyl-1,3-he Polyhydric alcohols such as sundiol, ethyl-1,2,4-butanetriol, 1,2,3-butanetriol, 2,2,4-trimethyl-1,3-pentanediol, petriol, ethylene glycol mono Polyhydric alcohol alkyl ethers such as ethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monophenyl ether, ethylene glycol mono Polyhydric alcohol aryl ethers such as benzyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl- -N-containing heterocyclic compounds such as pyrrolidone, 1,3-dimethyl-2-imidazolidinone, ε-caprolactam, γ-butyrolactone, formamide, N-methylformamide, N, N-dimethylformamide, 3-methoxy-N, Amides such as N-dimethylpropionamide and 3-butoxy-N, N-dimethylpropionamide, amines such as monoethanolamine, diethanolamine and triethylamine, sulfur-containing compounds such as dimethylsulfoxide, sulfolane and thiodiethanol, propylene carbonate, Examples thereof include ethylene carbonate.

  In addition to functioning as a wetting agent, it is preferable to use an organic solvent having a boiling point of 250 ° C. or lower because good drying properties can be obtained.

A polyol compound having 8 or more carbon atoms and a glycol ether compound are also preferably used. Specific examples of the polyol compound having 8 or more carbon atoms include 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, and the like.
Specific examples of glycol ether compounds include polyhydric alcohol alkyls such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, and propylene glycol monoethyl ether. Examples of ethers include polyhydric alcohol aryl ethers such as ethylene glycol monophenyl ether and ethylene glycol monobenzyl ether.
A polyol compound having 8 or more carbon atoms and a glycol ether compound can improve ink permeability when paper is used as a recording medium.

  The content of the organic solvent in the ink is not particularly limited and can be appropriately selected according to the purpose, but is preferably 10% by mass or more and 60% by mass or less from the viewpoint of the drying property and ejection reliability of the ink, 20 mass% or more and 60 mass% or less are more preferable.

  The ink of the present invention preferably contains a surfactant in order to enhance the permeability and wettability to plain paper or coated paper and further suppress the occurrence of beading.

<Surfactant>
As the surfactant, any of silicone surfactants, fluorine surfactants, amphoteric surfactants, nonionic surfactants and anionic surfactants can be used.
There is no restriction | limiting in particular in silicone type surfactant, According to the objective, it can select suitably. Among them, those that do not decompose even at high pH are preferable, and examples thereof include side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, and side chain both terminal modified polydimethylsiloxane. Those having an oxyethylene group or a polyoxyethylene polyoxypropylene group are particularly preferred because they exhibit good properties as an aqueous surfactant. In addition, as the silicone surfactant, a polyether-modified silicone surfactant can be used, and examples thereof include a compound in which a polyalkylene oxide structure is introduced into the side chain of the Si portion of dimethylsiloxane.

Examples of the fluorosurfactant include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate compound, a perfluoroalkyl ethylene oxide adduct, and a perfluoroalkyl ether group in the side chain. Polyoxyalkylene ether polymer compounds are particularly preferred because of their low foaming properties. Examples of the perfluoroalkyl sulfonic acid compound include perfluoroalkyl sulfonic acid, perfluoroalkyl sulfonate, and the like. Examples of the perfluoroalkylcarboxylic acid compound include perfluoroalkylcarboxylic acid and perfluoroalkylcarboxylate. Examples of the polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain include a sulfate ester salt of a polyoxyalkylene ether polymer having a perfluoroalkyl ether group in the side chain and a perfluoroalkyl ether group in the side chain. Examples thereof include salts of polyoxyalkylene ether polymers. As counter ions of salts in these fluorosurfactants, Li, Na, K, NH ₄ , NH ₃ CH ₂ CH ₂ OH, NH ₂ (CH ₂ CH ₂ OH) ₂ , NH (CH ₂ CH ₂ OH) ₃ etc. are mentioned.

  Examples of amphoteric surfactants include lauryl aminopropionate, lauryl dimethyl betaine, stearyl dimethyl betaine, and lauryl dihydroxyethyl betaine.

Nonionic surfactants include, for example, polyoxyethylene alkylphenyl ether, polyoxyethylene alkyl ester, polyoxyethylene alkylamine, polyoxyethylene alkylamide, polyoxyethylene propylene block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan Examples include fatty acid esters and ethylene oxide adducts of acetylene alcohol.
Examples of the anionic surfactant include polyoxyethylene alkyl ether acetate, dodecylbenzene sulfonate, laurate, polyoxyethylene alkyl ether sulfate salt, and the like. These may be used alone or in combination of two or more.

  The silicone surfactant is not particularly limited and may be appropriately selected depending on the intended purpose. For example, side chain modified polydimethylsiloxane, both terminal modified polydimethylsiloxane, one terminal modified polydimethylsiloxane, side Since both ends of the chain are modified with polydimethylsiloxane, a polyether-modified silicone surfactant having a polyoxyethylene group or a polyoxyethylene polyoxypropylene group as a modifying group exhibits good properties as an aqueous surfactant. preferable.

  As such a surfactant, an appropriately synthesized product or a commercially available product may be used. Commercially available products can be obtained from, for example, Big Chemie Co., Ltd., Shin-Etsu Chemical Co., Ltd., Toray Dow Corning Silicone Co., Ltd., Nippon Emulsion Co., Ltd., and Kyoeisha Chemical Co., Ltd.

There is no restriction | limiting in particular as said polyether modified silicone surfactant, According to the objective, it can select suitably, For example, the polyalkylene oxide structure represented by a general formula (S-1) type | formula is dimethylpolyethylene. Examples thereof include those introduced into the side chain of Si part of siloxane.
Formula (S-1)

(In the general formula (S-1), m, n, a, and b represent integers. R and R 'represent an alkyl group and an alkylene group.)

  A commercial item can be used as said polyether modified silicone type surfactant, For example, KF-618, KF-642, KF-643 (Shin-Etsu Chemical Co., Ltd.), EMALEX-SS-5602, SS- 1906EX (Japan Emulsion Co., Ltd.), FZ-2105, FZ-2118, FZ-2154, FZ-2161, FZ-2162, FZ-2163, FZ-2164 (Toray Dow Corning Silicone Co., Ltd.), BYK-33, BYK-387 (Bic Chemie Co., Ltd.), TSF4440, TSF4452, TSF4453 (Toshiba Silicon Co., Ltd.), etc. are mentioned.

As the fluorine-based surfactant, a fluorine-substituted compound having 2 to 16 carbon atoms is preferable, and a fluorine-substituted compound having 4 to 16 carbon atoms is more preferable.
Examples of the fluorosurfactant include perfluoroalkyl phosphate compounds, perfluoroalkylethylene oxide adducts, and polyoxyalkylene ether polymer compounds having a perfluoroalkyl ether group in the side chain.

Among these, a polyoxyalkylene ether polymer compound having a perfluoroalkyl ether group in the side chain is preferable because of its low foaming property, and in particular, fluorine-based compounds represented by the general formulas (F-1) and (F-2) A surfactant is preferred.
Formula (F-1)

  In the compound represented by the general formula (F-1), m is preferably an integer of 0 to 10 and n is preferably an integer of 0 to 40 in order to impart water solubility.

Formula (F-2)
_{C n F 2n + 1- CH 2} CH (OH) CH 2 -O- (CH 2 CH 2 O) a -Y

In the compound represented by the general formula (F-2), Y is H, or CnF _{2n + 1} , n is an integer of 1 to 6, or CH ₂ CH (OH) CH ₂ —CnF _{2n + 1,} where n is 4 to 6. An integer, or CpH _{2p + 1} , p is an integer of 1-19. a is an integer of 4-14.

A commercial item may be used as said fluorosurfactant.
As this commercial item, for example, Surflon S-111, S-112, S-113, S-121, S-131, S-132, S-141, S-145 (all manufactured by Asahi Glass Co., Ltd.); Fullrad FC-93, FC-95, FC-98, FC-129, FC-135, FC-170C, FC-430, FC-431 (all manufactured by Sumitomo 3M Limited); Megafac F-470, F -1405, F-474 (all manufactured by DIC Corporation); Zonyl TBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, UR (all manufactured by DuPont) ); FT-110, FT-250, FT-251, FT-400S, FT-150, FT-400SW (all manufactured by Neos Co., Ltd.), Refox PF-136A, PF-156A, PF-151N, PF-154, PF-159 (manufactured by Omninova), Unidyne DSN-403N (manufactured by Daikin Kogyo Co., Ltd.), etc., among these, good printing PF-300 manufactured by DuPont, FT-110 manufactured by Neos, FT-250, FT-251, FT -400S, FT-150, FT-400SW, Polynova PF-151N manufactured by Omninova, and Unidyne DSN-403N manufactured by Daikin Industries, Ltd. are particularly preferable.

  There is no restriction | limiting in particular as content of surfactant in an ink, Although it can select suitably according to the objective, From the point which is excellent in wettability and discharge stability, and image quality improves, it is 0.001 mass. % To 5% by mass is preferable, and 0.05% to 5% by mass is more preferable.

  The ink of the present invention preferably contains, for example, an antiseptic / antifungal agent, a rust inhibitor, a pH adjuster and the like as the other components as necessary.

<Antiseptic and antifungal agent>
The antiseptic / antifungal agent is not particularly limited, and examples thereof include 1,2-benzisothiazolin-3-one.

<Rust preventive>
There is no restriction | limiting in particular as a rust preventive agent, For example, acidic sulfite, sodium thiosulfate, etc. are mentioned.

<PH adjuster>
The pH adjuster is not particularly limited as long as the pH can be adjusted to 7 or more, and examples thereof include amines such as diethanolamine and triethanolamine.

There is no restriction | limiting in particular as a physical property of an ink, According to the objective, it can select suitably, For example, it is preferable that a viscosity, surface tension, pH, etc. are the following ranges.
The viscosity at 25 ° C. of the ink is preferably 5 mPa · s or more and 30 mPa · s or less, preferably 5 mPa · s or more and 25 mPa · s or less from the viewpoint of improving the printing density and character quality and obtaining good discharge properties. More preferred. Here, for the viscosity, for example, a rotary viscometer (RE-80L manufactured by Toki Sangyo Co., Ltd.) can be used. Measurement conditions are 25 ° C., standard cone rotor (1 ° 34 ′ × R24), sample liquid amount 1.2 mL, rotation speed 50 rpm, and measurement is possible for 3 minutes.
The surface tension of the ink is preferably 35 mN / m or less and more preferably 32 mN / m or less at 25 ° C. from the viewpoint that the ink is suitably leveled on the recording medium and the drying time of the ink is shortened.
The pH of the ink is preferably 7 to 12 and more preferably 8 to 11 from the viewpoint of preventing corrosion of the metal member in contact with the liquid.

(Ink production method)
The ink production method of the present invention includes water, a colorant, a structural unit represented by the following general formulas (1) and (2), a copolymer having a crosslinked structure with a crosslinking agent, and the other components described above. Can be dispersed or dissolved in an aqueous medium and mixed by stirring. Further, the copolymer may be used as a color material-dispersed resin when producing a color material dispersion.
The dispersion can be performed by, for example, a sand mill, a homogenizer, a ball mill, a paint shaker, or ultrasonic dispersion. The stirring and mixing can be performed by a stirrer using a normal stirring blade, a magnetic stirrer, a high-speed disperser or the like.

<Recorded material>
The recorded matter of the present invention has an image formed on the recording medium using the ink of the present invention.
Recording can be performed by recording with an inkjet recording apparatus and an inkjet recording method.

(Ink container)
The ink container of the present invention is an ink container having an ink container that stores ink, and the ink stored in the ink container is the ink of the present invention. The ink is contained in a container, and further includes other members appropriately selected as necessary.
The container is not particularly limited, and its shape, structure, size, material, etc. can be appropriately selected according to the purpose. For example, at least an ink container formed of an aluminum laminate film, a resin film, etc. What has is suitable.

<Recording apparatus and recording method>
The recording method of the present invention includes an ink applying step of applying the ink of the present invention to a recording medium, and a drying step of heating and drying the ink applied on the recording medium.
The ink of the present invention can be suitably used for various recording apparatuses using an ink jet recording method, such as a printer, a facsimile apparatus, a copying apparatus, a printer / fax / copier complex machine, and a three-dimensional modeling apparatus.
In the present invention, the recording apparatus and the recording method are an apparatus capable of ejecting ink, various treatment liquids, and the like to a recording medium, and a method of performing recording using the apparatus. The recording medium means a medium on which ink or various processing liquids can be temporarily attached.
The recording apparatus can include not only a head portion that ejects ink but also means for feeding, transporting, and discharging a recording medium, and other devices called pre-processing devices and post-processing devices. .
The recording apparatus and the recording method may include a heating unit used in the heating step and a drying unit used in the drying step. The heating means and the drying means include, for example, a means for heating and drying the printing surface and the back surface of the recording medium. Although it does not specifically limit as a heating means and a drying means, For example, a warm air heater and an infrared heater can be used. Heating and drying can be performed before printing, during printing, after printing, and the like.
Further, the recording apparatus and the recording method are not limited to those in which significant images such as characters and figures are visualized by ink. For example, what forms patterns, such as a geometric pattern, etc. includes what forms a three-dimensional image.
Further, the recording apparatus includes both a serial type apparatus that moves the ejection head and a line type apparatus that does not move the ejection head, unless otherwise specified.
Furthermore, this recording apparatus can use not only a desktop type but also a wide recording apparatus that can print on an A0 size recording medium, for example, a continuous paper wound up in a roll shape as a recording medium. Also included are continuous paper printers.

An example of the recording apparatus will be described with reference to FIGS. FIG. 1 is a perspective view of the apparatus. FIG. 2 is an explanatory perspective view of the main tank. An image forming apparatus 400 as an example of a recording apparatus is a serial type image forming apparatus. A mechanism unit 420 is provided in the exterior 401 of the image forming apparatus 400. Each ink storage portion 411 of the main tank 410 (410k, 410c, 410m, 410y) for each color of black (K), cyan (C), magenta (M), yellow (Y) is packaged, for example, an aluminum laminate film It is formed by a member. The ink storage unit 411 is stored in, for example, a plastic container case 414. As a result, the main tank 410 is used as an ink cartridge for each color.
On the other hand, a cartridge holder 404 is provided on the inner side of the opening when the cover 401c of the apparatus main body is opened. A main tank 410 is detachably attached to the cartridge holder 404. Thus, the ink discharge ports 413 of the main tank 410 and the discharge heads 434 for the respective colors communicate with each other via the supply tubes 436 for the respective colors, and ink can be discharged from the discharge heads 434 to the recording medium.
The method of using the ink is not limited to the ink jet recording method, and can be widely used. Besides the ink jet recording method, for example, a blade coating method, a gravure coating method, a bar coating method, a roll coating method, a dip coating method, a curtain coating method, a slide coating method, a die coating method, a spray coating method and the like can be mentioned.

The use of the ink of the present invention is not particularly limited and can be appropriately selected depending on the purpose. For example, it can be applied to printed materials, paints, coating materials, foundations and the like. Furthermore, it can be used not only to form two-dimensional characters and images using ink, but also as a three-dimensional modeling material for forming a three-dimensional three-dimensional image (three-dimensional modeled object).
A known three-dimensional modeling apparatus for modeling a three-dimensional model can be used, and is not particularly limited. For example, a three-dimensional modeling apparatus including an ink storage unit, a supply unit, a discharge unit, a drying unit, or the like is used. be able to. The three-dimensional structure includes a three-dimensional structure obtained by repeatedly applying ink. Further, a molded product obtained by processing a structure provided with ink on a substrate such as a recording medium is also included. The molded product is obtained by subjecting a recorded material or a structure formed in a sheet shape or a film shape to a molding process such as heat stretching or punching, for example, an automobile, an OA device, an electric -It is suitably used for applications in which surfaces are decorated after decorating, such as meters for electronic devices, cameras, etc., and panels for operation units.

  Further, the terms “image formation”, “recording”, “printing”, “printing”, etc. in the terms of the present invention are all synonymous.

  EXAMPLES Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated further more concretely, this invention is not limited by these examples. Unless otherwise specified, “part” or “%” is based on mass.

Moreover, the average molecular weight of the copolymer in this specification was calculated | required as follows.
<Measurement of average molecular weight of copolymer>
The measurement was carried out under the following conditions by GPC (Gel Permeation Chromatography).
・ Device: GPC-8020 (manufactured by Tosoh Corporation)
Column: TSK G2000HXL and G4000HXL (manufactured by Tosoh Corporation)
・ Temperature: 40 ℃
・ Solvent: THF (tetrahydrofuran)
-Flow rate: 1.0 mL / min 1 mL of a copolymer having a concentration of 0.5% by mass was injected, and a molecular weight calibration curve prepared from a monodisperse polystyrene standard sample from the molecular weight distribution of the copolymer measured under the above conditions was used. The number average molecular weight Mn and the weight average molecular weight Mw of the copolymer were calculated.

<Synthesis example>
<Synthesis Example 1: Synthesis of Copolymer CP-1 Aqueous Solution>
48.8 g (787 mmol) of ethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 200 mL of methylene chloride, and 21.8 g (275 mmol) of pyridine was added. To this solution, a solution prepared by dissolving 50.0 g (262 mmol) of 2-naphthalenecarbonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) in 100 mL of methylene chloride was added dropwise over 30 minutes with stirring, and then at room temperature for 6 hours. Stir. After the obtained reaction solution was washed with water, the organic phase was isolated and dried over magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 99/1) as an eluent to obtain 72.6 g of compound A-1.

  32.4 g (150 mmol) of Compound A-1 was dissolved in 80 mL of ultra-dehydrated dichloromethane (Wako Pure Chemical Industries, Ltd.). To this solution, 21.2 g (150 mmol) of 2-methacryloyloxyethyl isocyanate (manufactured by Showa Denko KK, Karenz MOI) was added dropwise with stirring over 1 hour, and then stirred at 40 ° C. for 12 hours. The solvent was distilled off, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 99/1) as an eluent to obtain 46.1 g of monomer M-1 as the target product. Obtained.

  Then 4.00 g (55.5 mmol) of acrylic acid (Aldrich) and 17.01 g (47.6 mmol) of monomer M-1 and 0.721 g (4.39 mmol) of 2,2′-azoiso (Butyronitrile) (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 128 mL of methyl ethyl ketone (manufactured by Kanto Chemical Co., Inc.) to prepare a monomer solution. After adding 32 mL of methyl ethyl ketone (manufactured by Kanto Chemical Co., Inc.) to the reaction vessel and heating to 75 ° C. under an argon stream, the monomer solution was added dropwise over 1 hour and stirred for 5 hours under reflux. After cooling to room temperature, the resulting reaction solution was dropped into hexane. The precipitated copolymer was filtered off and dried under reduced pressure to obtain 21.57 g of the copolymer.

  Next, 20.00 g of copolymer, 4.71 g (44.8 mmol) of diethanolamine, and 1.00 g (5.74 mmol) of polyethylene glycol glycidyl ether (manufactured by Nagase ChemteX Corp., Denacol EX-850) 231 A copolymer solution was prepared by dissolving in .39 g of ion exchange water. This copolymer solution was heated to 70 ° C. under an argon stream, and then stirred for 5 hours, whereby a copolymer CP-1 aqueous solution having a crosslinked structure of 257.10 g (copolymer solid content concentration: 10% by mass). , Weight average molecular weight (Mw): 20,200, number average molecular weight (Mn) 8,900).

<Synthesis Examples 2-9: Synthesis of Copolymer CP-2-9 Aqueous Solution>
A copolymer CP2-9 aqueous solution was obtained in the same manner as in the synthesis of the copolymer CP-1 aqueous solution except that the diol and the crosslinking agent shown in Table 1 were used in the synthesis of the copolymer CP-1 aqueous solution. All crosslinkers used were Denasel manufactured by Nagase ChemteX Corporation.

(Preparation Example 1 of Pigment Dispersion)
-Preparation of pigment dispersion PD-1-
Ion exchange water was added to 60 g of the copolymer CP-1 aqueous solution of Synthesis Example 1 to make the total amount of the aqueous solution 80.0 parts. 20.0 parts of carbon black (NIPEX150, manufactured by Degussa) was added to 80.0 parts of the obtained aqueous solution and stirred for 12 hours. The obtained mixture was circulated and dispersed for 1 hour at a peripheral speed of 10 m / s using a disk-type bead mill (Shinmaru Enterprises Co., Ltd., KDL type, media: using zirconia balls having a diameter of 0.1 mm), and then the average pore size was measured. The mixture was filtered through a 1.2 μm membrane filter, and an adjusted amount of ion-exchanged water was added to obtain 98.0 parts by mass of [Pigment Dispersion PD-1] (pigment solid content concentration: 20% by mass).

(Preparation Examples 2 to 12 of Pigment Dispersion)
-Preparation of pigment dispersions PD-2 to 12-
In Preparation Example 1 of Pigment Dispersion, except for using the copolymers CP-2 to 9 in the content (parts by mass) shown in Table 2 and using the pigment shown in Table 2, Preparation Example 1 of Pigment Dispersion and Similarly, pigment dispersions PD-2 to 12 were obtained.

In Table 2, the following products were used as pigments.
・ Carbon black (NIPEX150, manufactured by Degussa)
Pigment Red 122 (Toner Magenta E02, manufactured by Clariant Japan)
Pigment Blue 15: 3 (Chromo Fine Blue A-220JC, manufactured by Dainichi Seika Co., Ltd.) Pigment Yellow 74 (First Yellow 531, manufactured by Dainichi Seika Kogyo Co., Ltd.)

Example 1
-Preparation of ink GJ-1-
40.0 parts by weight of Pigment Dispersion PD-1, 10.0 parts by weight of glycerin, 15.0 parts by weight of 1,3-butanediol, 10.0 parts by weight of 3-methoxy-N, N-dimethylpropion Amide, 5.0 parts by mass of ethylene glycol monobutyl ether, 1.0 part by mass of 2-ethyl-1,3-hexanediol, 1.0 part by mass of Unidyne DSN-403N (manufactured by Daikin Industries, Ltd.), and 18 0.0 parts by mass of ion-exchanged water was mixed and stirred for 1 hour, and then filtered through a membrane filter having an average pore size of 1.2 μm to prepare ink GJ-1 of Example 1.

(Examples 2 to 12)
-Preparation of inks GJ-2 to 12-
Inks GJ-2 to 12 of Examples 2 to 12 were produced in the same manner as in Example 1, except that the ink formulation shown in Table 3 was changed to Example 1.

(Comparative Example 1)
[Synthesis of Copolymer RCP-2]
48.8 g (787 mmol) of ethylene glycol (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 200 mL of methylene chloride, and 21.8 g (275 mmol) of pyridine was added. To this solution, a solution prepared by dissolving 50.0 g (262 mmol) of 2-naphthalenecarbonyl chloride (manufactured by Tokyo Chemical Industry Co., Ltd.) in 100 mL of methylene chloride was added dropwise over 30 minutes with stirring, and then at room temperature for 6 hours. Stir. After the obtained reaction solution was washed with water, the organic phase was isolated and dried over magnesium sulfate, and the solvent was distilled off. The residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 99/1) as an eluent to obtain 72.6 g of compound A-1.

  32.4 g (150 mmol) of Compound A-1 was dissolved in 80 mL of ultra-dehydrated dichloromethane (Wako Pure Chemical Industries, Ltd.). To this solution, 21.2 g (150 mmol) of 2-methacryloyloxyethyl isocyanate (manufactured by Showa Denko KK, Karenz MOI) was added dropwise with stirring over 1 hour, and then stirred at 40 ° C. for 12 hours. The solvent was distilled off, and the residue was purified by silica gel column chromatography using a mixed solvent of methylene chloride / methanol (volume ratio 99/1) as an eluent to obtain 46.1 g of monomer M-1 as the target product. Obtained.

  3.80 g (44.1 mmol) of acrylic acid (Aldrich), and 16.01 g (43.1 mmol) of monomer M-1 and 0.721 g (4.39 mmol) of 2,2′-azoiso (Butyronitrile) (manufactured by Tokyo Chemical Industry Co., Ltd.) was dissolved in 128 mL of methyl ethyl ketone (manufactured by Kanto Chemical Co., Inc.) to prepare a monomer solution. After adding 32 mL of methyl ethyl ketone (manufactured by Kanto Chemical Co., Inc.) to the reaction vessel and heating to 75 ° C. under an argon stream, the monomer solution was added dropwise over 1 hour and stirred for 5 hours under reflux. After cooling to room temperature, the resulting reaction solution was dropped into hexane. The precipitated copolymer was filtered off and dried under reduced pressure to obtain 19.57 g of copolymer RCP-2 (weight average molecular weight (Mw): 20,200, number average molecular weight (Mn) 8,900). It was.

-Preparation of pigment dispersion RPD-2-
6.0 parts of copolymer RCP-2 was dissolved in 50.0 parts of diethanolamine aqueous solution so that the pH was 8.0. Further, ion exchange water was added to make the total amount of the aqueous solution 80.0 parts. 20.0 parts of carbon black (NIPEX150, manufactured by Degussa) was added to 80.0 parts of the obtained aqueous solution and stirred for 12 hours.
The obtained mixture was circulated and dispersed for 1 hour at a peripheral speed of 10 m / s using a disk-type bead mill (Shinmaru Enterprises Co., Ltd., KDL type, media: using zirconia balls having a diameter of 0.1 mm), and then the average pore size was measured. The mixture was filtered through a 1.2 μm membrane filter, and an adjusted amount of ion-exchanged water was added to obtain 97.0 parts by mass of [pigment dispersion RPD-2] (pigment solid content concentration: 20% by mass).

-Preparation of ink RGJ-2-
Next, a comparative ink RGJ-2 was obtained in the same manner as in Example 1 except that the comparative pigment dispersion RPD-2 was used instead of the pigment dispersion PD-1 in the preparation of the ink of Example 1. .

(Comparative Example 2)
-Preparation of pigment dispersion RPD-3-
6.0 parts of copolymer RCP-2 was dissolved in 50.0 parts of diethanolamine aqueous solution so that the pH was 8.0. Further, ion exchange water was added to make the total amount of the aqueous solution 84.0 parts. To 84.0 parts of the resulting aqueous solution, 20.0 parts of Pigmet Red 122 (Toner Magenta E02, manufactured by Clariant) were added and stirred for 12 hours.
The obtained mixture was circulated and dispersed for 1 hour at a peripheral speed of 10 m / s using a disk-type bead mill (Shinmaru Enterprises Co., Ltd., KDL type, media: using zirconia balls having a diameter of 0.1 mm), and then the average pore size was measured. The mixture was filtered through a 1.2 μm membrane filter, and an adjusted amount of ion-exchanged water was added to obtain 97.0 parts by mass of [pigment dispersion RPD-3] (pigment solid content concentration: 20% by mass).

-Preparation of ink RGJ-3-
Next, comparative ink RGJ-3 was obtained in the same manner as in Example 1, except that Comparative Pigment Dispersion RPD-3 was used instead of Pigment Dispersion PD-7 in the preparation of the ink of Example 7. .

(Comparative Example 3)
-Preparation of pigment dispersion RPD-4-
6.0 parts of copolymer RCP-2 was dissolved in 50.0 parts of diethanolamine aqueous solution so that the pH was 8.0. Further, ion exchange water was added to make the total amount of the aqueous solution 80.0 parts. 20.0 parts of Pigment Blue 15: 3 (Chromofine Blue A-220JC, manufactured by Dainichi Seika Co., Ltd.) was added to 80.0 parts of the resulting aqueous solution and stirred for 12 hours.
The obtained mixture was circulated and dispersed for 1 hour at a peripheral speed of 10 m / s using a disk-type bead mill (Shinmaru Enterprises Co., Ltd., KDL type, media: using zirconia balls having a diameter of 0.1 mm), and then the average pore size was measured. The mixture was filtered through a 1.2 μm membrane filter, and an adjusted amount of ion-exchanged water was added to obtain 97.0 parts by mass of [Pigment Dispersion RPD-4] (pigment solid content concentration: 20% by mass).

-Preparation of ink RGJ-4-
Next, a comparative ink RGJ-4 was obtained in the same manner as in Example 1 except that the comparative pigment dispersion RPD-4 was used instead of the pigment dispersion PD-11 in the preparation of the ink of Example 11. .

(Comparative Example 4)
-Preparation of pigment dispersion RPD-5-
6.0 parts of copolymer RCP-2 was dissolved in 50.0 parts of diethanolamine aqueous solution so that the pH was 8.0. Further, ion exchange water was added to make the total amount of the aqueous solution 80.0 parts. 20.0 parts of Pigment Yellow 74 (First Yellow 531; manufactured by Dainichi Seika Co., Ltd.) was added to 80.0 parts of the obtained aqueous solution and stirred for 12 hours.
The obtained mixture was circulated and dispersed for 1 hour at a peripheral speed of 10 m / s using a disk-type bead mill (Shinmaru Enterprises Co., Ltd., KDL type, media: using zirconia balls having a diameter of 0.1 mm), and then the average pore size was measured. The mixture was filtered through a 1.2 μm membrane filter, and an adjusted amount of ion-exchanged water was added to obtain 97.0 parts by mass of [Pigment Dispersion RPD-5] (pigment solid content concentration: 20% by mass).

-Preparation of ink RGJ-5-
Next, a comparative ink RGJ-5 was obtained in the same manner as in Example 1 except that the comparative pigment dispersion RPD-5 was used instead of the pigment dispersion PD-9 in the preparation of the ink of Example 9. .

Next, the characteristics of the inks produced in Examples 1 to 12 and Comparative Examples 1 to 4 were evaluated by the following methods. The results are summarized in Table 4.

<Ink storage stability>
Each ink was filled in an ink container and stored at 70 ° C. for 1 week. The change rate of the viscosity after storage with respect to the viscosity before storage was obtained from the following formula and evaluated according to the following criteria.

  For measurement of the viscosity, a viscometer (RE80L, manufactured by Toki Sangyo Co., Ltd.) was used, and the viscosity at 25 ° C. was measured at 50 revolutions.

[Evaluation criteria]
A: Change rate of viscosity is within ± 5% B: Change rate of viscosity exceeds ± 5% and within ± 8% C: Change rate of viscosity exceeds ± 8% and within ± 10% D: Change in viscosity Rate exceeds ± 10% and within ± 30% E: Viscosity change rate exceeds ± 30% (cannot be evaluated due to gelation)

<Image density>
General of 64 points JIS X 0208 (1997), 2223 created by Microsoft Word 2000 (manufactured by Microsoft) by filling each ink in an ink jet printer (IPSiO GX5000, manufactured by Ricoh Co., Ltd.) under an environment of 23 ° C. and 50% RH. The chart on which the symbols are described is stamped on plain paper (MyPaper, manufactured by Ricoh Co., Ltd.) and coated paper (Lumiart gloss paper, paper thickness 90 g / m ² , manufactured by STORA ENSO). Drying was performed for a minute. The symbol part of the printed surface was measured by X-Rite 938 (manufactured by X-Rite Co., Ltd.) and evaluated according to the following evaluation criteria.
As the print mode, a mode in which the “plain paper-standard fast” mode is changed to “no color correction” from the user setting for plain paper by using a driver attached to the printer.
Note that JIS X 0208 (1997), 2223 is a symbol whose outer shape is a regular square and the entire surface of the symbol is filled with ink.

[Evaluation criteria]
<Image density 1 (plain paper)>
A: 1.25 or more B: 1.20 or more and less than 1.25 C: 1.10 or more and less than 1.20 D: less than 1.10 E: The pigment is gelled and cannot be dispersed in the ink, and printing cannot be performed.
<Image density 2 (coated paper)>
A: 1.90 or more B: 1.80 or more and less than 1.90 C: 1.70 or more and less than 1.80 D: less than 1.70 E: The pigment gelates and cannot be dispersed in the ink, and printing cannot be performed.

  From the results of Table 4, the ink containing the copolymer having the crosslinked structure of the structural units represented by the general formulas (1) and (2) of Examples 1 to 12 and the crosslinking agent is that of Comparative Examples 1 to 4. It was found that the image density was higher than that of ink.

400 Image forming apparatus 401 Exterior of image forming apparatus 401c Cover of apparatus main body 404 Cartridge holder 410 Main tank 410k, 410c, 410m, 410y For each color of black (K), cyan (C), magenta (M), yellow (Y) Main tank 411 Ink storage section 413 Ink discharge port 414 Storage container case 420 Mechanism section 434 Discharge head 436 Supply tube

JP 2011-105866 A US Patent Application Publication No. 2016/0017075

Claims (10)

An ink containing water, a coloring material, and a crosslinked product having a structural unit represented by the following general formulas (1) and (2).

However, in the said General formula (1), X is a hydrogen atom or a cation, R1 represents a hydrogen atom or a methyl group, R2 is a hydrogen atom or a methyl group in General formula (2), L Represents an alkylene group having 2 to 18 carbon atoms. * Is a bond.   The ink according to claim 1, wherein the crosslinked product is a copolymer having a structural unit represented by the general formulas (1) and (2) and a crosslinked structure by a crosslinking agent.   The ink according to claim 2, wherein the cross-linking agent is a compound having two or more epoxy groups in a molecule.   The ink according to claim 2 or 3, wherein the content of the crosslinking agent in the copolymer is 0.1 to 10% by mass.   The ink according to any one of claims 1 to 4, wherein a molar ratio of the structural units represented by the general formulas (1) and (2) is 0.5: 1 to 3: 1 as the former: the latter.   The ink according to any one of claims 2 to 5, wherein the copolymer has a weight average molecular weight of 5,000 or more and 40,000 or less.   The ink according to claim 1, wherein the color material is a pigment.   8. An ink cartridge comprising the ink according to claim 1 contained in a container.   An ink application process for applying the ink according to claim 1 to a recording medium, and a drying process for heating and drying the ink applied on the recording medium. An image forming method. A printed matter having an image on a recording medium, the image containing a color material and a crosslinked product having a structural unit represented by the following general formulas (1) and (2).

However, in the said General formula (1), X is a hydrogen atom or a cation, R1 represents a hydrogen atom or a methyl group, R2 is a hydrogen atom or a methyl group in General formula (2), L Represents an alkylene group having 2 to 18 carbon atoms. * Is a bond.

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