JP6632027B2 - Ink and inkjet recording method - Google Patents

Description

  The present invention relates to an aqueous ink, an ink jet recording method using the ink, and a recording medium to which the ink is attached.

  Among various color recording methods, a recording method using an inkjet printer (inkjet recording method) is one of typical methods. The ink jet recording method is a method of performing recording by generating small droplets of ink and attaching the droplets to a recording medium such as paper. In recent years, demand for the inkjet recording method for industrial use has been increasing. Ink jet recording for industrial use is required to be able to record at high speed and on various types of recording media.

  On the other hand, the problems of the ink used for inkjet recording include good storage stability and scratch resistance of the recorded image. As a means for solving such a problem, a method has been proposed in which a penetrating agent is added to the ink to improve the permeability of the ink to the recording medium, thereby improving the scratch resistance. However, due to the improvement in ink permeability, a sufficient density of a recorded image may not be obtained, and this is a new problem.

Therefore, it has been proposed to add a polymer to the ink as in Patent Documents 1 and 2, for example.
On the other hand, the applicant of the present application has proposed, for example, in Patent Document 5, an ink that can be easily redispersed by adding water even when the ink is dried. In addition, for example, Patent Document 6 proposes an ink composition having scratch resistance, and excellent in ejection property and redispersibility.
Inks containing a plurality of polymers have been proposed in, for example, Patent Documents 3 and 4.
However, it has been difficult to achieve both abrasion resistance and storage stability by using the inks obtained by these proposals.
JP 2013-166844 A JP 2013-199605 A US Publication No. 2007/0129462 US Patent No. 8,573,761 International Publication No. 2013/115071 Gazette International Publication No. 2015/147192 Gazette

  An object of the present invention is to provide an ink having excellent fixability and storage stability, an inkjet recording method using the ink, and a recording medium to which the ink is attached.

  The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that the above-mentioned problems can be solved by ink containing specific three types of polymers, and have completed the present invention.

That is, the present invention relates to the following 1) to 15).
A colorant, water, and an ink containing a first polymer, a second polymer, and a third polymer, each of which has a different configuration of a monomer, wherein the monomers constituting the first to third polymers are methacrylic acid derivatives, Ink that is a monomer selected from acrylic acid derivatives and styrene derivatives.
2)
The monomer constituting the first polymer is a monomer selected from methacrylic acid derivatives,
The monomer constituting the second polymer is a monomer selected from at least one of each of an acrylic acid derivative and a styrene derivative,
The ink according to 1), wherein the monomer constituting the third polymer is a monomer selected from at least one of each of a methacrylic acid derivative and an acrylic acid derivative.
3)
The ink according to 1), wherein the monomers constituting the first polymer are three types of monomers selected from methacrylic acid derivatives.
4)
The ink according to the above 1), wherein the first polymer is an AB block polymer composed of two blocks, an A block and a B block.
5)
The ink according to any one of 1) to 4) above, wherein the first polymer is a dispersant for a colorant.
6)
The ink according to 1), wherein the monomers constituting the third polymer are three types of monomers selected from methacrylic acid derivatives and one type of monomer selected from acrylic acid derivatives.
7)
The ink according to 1), wherein the monomer selected from the methacrylic acid derivative is a monomer selected from the group consisting of aralkyl methacrylate, alkyl methacrylate, and methacrylic acid.
8)
The ink according to the above 1), wherein the monomer selected from the styrene derivative is a monomer selected from styrene and α-methylstyrene.
9)
The ink according to the above item 1), wherein the monomer selected from the acrylic acid derivative is a monomer selected from the group consisting of aralkyl acrylate, alkyl acrylate, and acrylic acid.
10)
The ink according to any one of 1) to 3), wherein the monomers constituting the first polymer are aralkyl methacrylate, alkyl methacrylate, and methacrylic acid.
11)
The ink according to 4), wherein the A block is an aralkyl methacrylate or an aralkyl methacrylate and methacrylic acid, and the B block is an AB block polymer composed of an alkyl methacrylate and methacrylic acid.
12)
The ink according to any one of 1) to 3), wherein the monomers constituting the third polymer are two kinds of alkyl methacrylate, methacrylic acid, and alkyl acrylate.
13)
13. An ink jet recording method for performing recording by ejecting ink droplets according to any one of 1) to 12) in accordance with a recording signal and attaching the ink droplets to a recording medium.
14)
13. A recording medium to which the ink according to any one of 1) to 12) is attached.
15)
An ink jet printer having a container containing the ink according to any one of the above 1) to 12).

  According to the present invention, an ink having excellent fixability and storage stability, an ink jet recording method using the ink, and a recording medium to which the ink adheres can be provided.

  In the present specification, “CI” means “color index”. Unless otherwise specified, all “%” and “parts” are described on a mass basis, including in Examples.

[monomer]
Examples of the monomer constituting the polymer include a monomer selected from a methacrylic acid derivative, an acrylic acid derivative, and a styrene derivative.
Examples of the polymer include polymers obtained by block copolymerization, random copolymerization, graft copolymerization, and the like.

[Methacrylic acid derivative]
As the methacrylic acid derivative, aralkyl methacrylate, alkyl methacrylate, and methacrylic acid are preferable.
The aralkyl methacrylate (arylalkyl methacrylate) generally includes C6-C14 aryl C1-C4 alkyl methacrylate, and preferably C6-C10 aryl C1-C3 alkyl methacrylate. Specific examples thereof include benzyl methacrylate, phenethyl methacrylate, phenylpropyl methacrylate, phenylbutyl methacrylate, naphthylmethyl methacrylate, anthracenylmethyl methacrylate and the like. Among these, benzyl methacrylate is preferred.
As the alkyl methacrylate, the alkyl moiety is usually C1-C18, preferably C1-C12, more preferably C1-C8, and includes a saturated or unsaturated alkyl methacrylate.
Specific examples of the saturated alkyl methacrylate include linear alkyl methacrylates such as methyl methacrylate, butyl methacrylate, and octyl methacrylate; branched alkyl methacrylates such as isopropyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, isohexyl methacrylate, and 2-ethylhexyl methacrylate; Cyclic alkyl methacrylates such as cyclopropyl methacrylate, cyclobutyl methacrylate, cyclopentyl methacrylate, and cyclohexyl methacrylate;
As the unsaturated alkyl methacrylate, an unsaturated C1-C4 alkyl methacrylate is more preferable. Specific examples include vinyl methacrylate, allyl methacrylate, propenyl methacrylate, butenyl methacrylate, butadienyl methacrylate, and the like.

[Acrylic acid derivative]
Examples of the acrylic acid derivative include compounds in which “methacrylic acid” in the above “methacrylic acid derivative” is read as “acrylic acid” and “methacrylate” is read as “acrylate”.

[Styrene derivative]
Styrene derivatives include styrene and α-methylstyrene.

[First polymer]
The monomer constituting the first polymer is preferably a monomer selected from methacrylic acid derivatives,
More preferably three types of monomers selected from methacrylic acid derivatives,
More preferred are aralkyl methacrylate, alkyl methacrylate, and methacrylic acid. Among the above monomers, the monomers constituting the first polymer are particularly preferably benzyl methacrylate, butyl methacrylate, and methacrylic acid.
The first polymer is preferably an AB block polymer composed of two blocks, an A block and a B block, and is, for example, an AB block polymer obtained by a living radical polymerization method disclosed in International Publication No. 2013/115071 Gazette. Is more preferred. The contents disclosed as preferable and more preferable, etc., of the gusset as the AB block polymer have the same meaning in the first polymer.
The A block is preferably composed of aralkyl methacrylate or aralkyl methacrylate and methacrylic acid. Further, the B block is preferably composed of alkyl methacrylate and methacrylic acid.
The first polymer can be obtained, for example, by a synthesis method disclosed in WO 2013/115071 Gazette.

  The acid value of the first polymer is usually 90 to 200 mgKOH / g, preferably 100 to 150 mgKOH / g, more preferably 100 to 120 mgKOH / g.

  The weight average molecular weight of the first polymer is usually 10,000 to 60,000, preferably 10,000 to 40,000, and more preferably 15,000 to 30,000.

  The first polymer is preferably used as a dispersant for stably dispersing the colorant. The ratio of the mass of the first polymer to the total mass of the colorant is usually 0.1 to 1.0, preferably 0.1 to 0.6, and more preferably 0.2 to 0.5.

[Second polymer]
The monomer constituting the second polymer is preferably a monomer selected from at least one of each of an acrylic acid derivative and a styrene derivative.
The second polymer can be synthesized. However, it can also be easily obtained as a commercial product. Commercially available products include, for example, the John Krill series manufactured by BASF. Specific examples thereof preferably include Joncryl series such as Joncryl 61J, 67, 68, 450, 55, 555, 586, 678, 680, 682, 683, 690; and B-36;

The second polymer can be used both as a dispersant and as an additive in the ink.
When the second polymer is used as a dispersant, the first polymer is preferably used in combination as a dispersant. When the first and second polymers are used in combination as a dispersant, a dispersion can be obtained by mixing both the first and second polymers and a colorant. Also, a dispersion containing each of the first polymer and the colorant, and each of the second polymer and the colorant is prepared, and both are mixed to prepare a dispersion containing both the first polymer and the second polymer and the colorant. You can also get
When the second polymer is used as an additive of the ink, a dispersion of the colorant is obtained from the first polymer and the colorant, and then the ink is obtained by adding the second polymer in the same manner as the other additives. be able to.
When a second polymer is used, its acid value can be neutralized. The neutralizing agent used for the neutralization and the amount of the neutralizing agent used (degree of neutralization) are the same as in the case of the first polymer.

  The content of the second polymer in the total mass of the ink is usually 0.1 to 10%, preferably 0.1 to 5%, more preferably 0.1 to 3%.

[Third polymer]
The monomer constituting the third polymer is preferably a monomer selected from at least one of each of a methacrylic acid derivative and an acrylic acid derivative,
Three types of monomers selected from methacrylic acid derivatives and one type of monomer selected from acrylic acid derivatives are more preferable,
Two types of alkyl methacrylate, methacrylic acid, and alkyl acrylate are more preferred.
The two types of alkyl methacrylates constituting the third polymer are preferably monomers selected from linear alkyl methacrylates and unsaturated alkyl methacrylates.
As the straight-chain alkyl methacrylate, the straight-chain C1-C3 alkyl methacrylate is more preferable, and methyl methacrylate is more preferable.
Among the above, the unsaturated alkyl methacrylate is more preferably an unsaturated C1-C4 alkyl methacrylate, and even more preferably allyl methacrylate.
Further, the alkyl acrylate constituting the third polymer is preferably a branched alkyl acrylate, more preferably a branched C1-C8 alkyl acrylate, and further preferably 2-ethylhexyl acrylate.
The third polymer can be obtained, for example, by a synthesis method disclosed in International Publication No. 2015/147192 Gazette. In addition, the third polymer can be used as an emulsion.

Table 1 below summarizes the monomer configuration of the third polymer as “normal”, “preferred”, and “more preferred”. In the range of each monomer in Table 1 below, the third polymer can be prepared so that the total amount of the monomers is 100 parts. The abbreviations in Table 1 below have the following meanings.
MA: methacrylic acid.
ScAM: linear alkyl methacrylate.
BcAA: branched-chain alkyl acrylate.
UsAM: unsaturated alkyl methacrylate.

The average particle size (D50) of the third polymer is usually from 10 nm to 1 μm, preferably from about 30 nm to 500 nm.
The glass transition point (TG) of the third polymer is usually -10C to 20C, preferably -5C to 15C.
The acid value of the third polymer is usually from 0 to 25 KOH mg / g, preferably from 5 to 15 KOH mg / g.
The insolubility of the third polymer in tetrahydrofuran is generally 80 to 100%, preferably 100%.

  The content of the third polymer in the total mass of the ink is usually 0.1 to 10%, preferably 0.1 to 8%, more preferably 0.5 to 4%.

When the polymer is used, a neutralizing agent that neutralizes the acid value of the polymer can be used. Examples of the neutralizing agent include an alkali metal hydroxide, an alkaline earth metal hydroxide, and an amine compound. As the neutralizing agent, about 1 to 5 kinds, preferably 1 to 4 kinds, more preferably about 1 to 3 kinds can be arbitrarily used.
Examples of the alkali metal hydroxide include lithium hydroxide, sodium hydroxide and potassium hydroxide. Examples of the alkaline earth metal hydroxide include beryllium hydroxide, magnesium hydroxide, calcium hydroxide, and strontium hydroxide.

Examples of the amine compound include ammonia (including aqueous ammonia), an alkylamine compound, and an alkylamine compound having a hydroxy group as a substituent.
Examples of the alkylamine compound include amine compounds having one to three C1-C6 alkyl groups. Specific examples thereof include, for example, monomethylamine, dimethylamine, trimethylamine, monoethylamine, dimethylamine and trimethylamine.
Examples of the amine compound having a hydroxy group as a substituent include an amine compound in which at least one of the alkyl groups of the alkylamine compound has a hydroxy group as a substituent. Specific examples thereof include monoethanolamine, diethanolamine, triethanolamine, monopropanolamine, dipropanolamine, tripropanolamine, methylethanolamine, dimethylethanolamine and N-methyldiethanolamine.

  The amount of the neutralizing agent used can be represented by the degree of neutralization. When the acid value of the first polymer is neutralized with a theoretical equivalent, the degree of neutralization is 100%. Neutralizing agents can be used in excess of stoichiometric amounts. The degree of neutralization of the first polymer is usually 50 to 200%, preferably 80 to 150%, more preferably 100 to 120%.

[Colorant]
The colorant can be arbitrarily selected from known pigments and dyes. One type of coloring agent may be used, or two or more types may be used in combination. When a colorant is used in combination, the number is usually 2 to 6, preferably 2 to 4.
The colorant is preferably hardly soluble or insoluble in water. The solubility of the colorant in one liter of water at 25 ° C. is usually 5 g or less, preferably 3 g or less, more preferably 1 g or less, and further preferably 500 mg or less. Examples of such a coloring agent include pigments (typically, CI Pigment), disperse dyes (typically, CI Disperse), and solvent dyes (typically, CI Solvent). No.

Pigments are roughly classified into inorganic pigments, organic pigments, and extenders.
Examples of the inorganic pigment include carbon black, metal oxide, hydroxide, sulfide, ferrocyanide, and metal chloride. Examples of the carbon black include thermal black, acetylene black, oil furnace black, gas furnace black, lamp black, gas black, and channel black. Carbon black includes, for example, Raven series of Columbia Carbon Co., Monarch series and Regal series of Cabot Corporation, ColorBlack series, Printex series of Orion Engineered Carbon Co., SpecialBlack series, Nerox series, and MA series of Mitsubishi Chemical Corporation, MCF. Various kinds of products can be easily purchased as a series or the like.

As the organic pigment, for example, a soluble azo pigment, an insoluble azo pigment, an insoluble diazo pigment, a condensed azo pigment, a phthalocyanine pigment, a quinacridone pigment, an isoindolinone pigment, a dioxazine pigment, a perylene pigment, a perinone pigment, a thioindigo pigment, an anthraquinone pigment, and And quinophthalone pigments.
Specific examples of the organic pigment include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 24, 55, 73, 74, 75, 83, 93, 94, 95, 97, 98, 108, 114, 128, 129, 138, Yellow pigments such as 139, 150, 151, 154, 180, 185, 193, 199, 202, 213; I. Pigment Red 5, 7, 12, 48, 48: 1, 57, 88, 112, 122, 123, 146, 149, 150, 166, 168, 177, 178, 179, 184, 185, 202, 206, 207, Red pigments such as 254, 255, 257, 260, 264, 272; I. Blue pigments such as CI Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 25, 60, 66, 80; I. Violet pigments such as C.I. Pigment Violet 19, 23, 29, 37, 38, 50; I. Orange-brown pigments such as CI Pigment Orange 13, 16, 68, 69, 71, 73; I. Green pigments such as CI Pigment Green 7, 36, 54; I. Pigment Black 1 and the like.

  Examples of the extender include silica, calcium carbonate, talc, clay, barium sulfate, and white carbon. These extender pigments can be used in combination with inorganic pigments or organic pigments for the purpose of improving the fluidity of the powder.

  Examples of the disperse dye include C.I. I. Disperss Yellow 9, 23, 33, 42, 49, 54, 58, 60, 64, 66, 71, 76, 79, 83, 86, 90, 93, 99, 114, 116, 119, 122, 126, 149, 160 Yellow dyes such as C.I., 163, 165, 180, 183, 186, 198, 200, 211, 224, 226, 227, 231, 237; I. Red dyes such as Disperses Red 60, 73, 88, 91, 92, 111, 127, 131, 143, 145, 146, 152, 153, 154, 167, 179, 191, 192, 206, 221, 258, 283; . I. Orange dyes such as Disperses Orange 9, 25, 29, 30, 31, 32, 37, 38, 42, 44, 45, 53, 54, 55, 56, 61, 71, 73, 76, 80, 96, 97; . I. Violet dyes such as Dispers Violet 25, 27, 28, 54, 57, 60, 73, 77, 79, 79: 1; I. Dispers Blue 27,56,60,79: 1,87,143,165,165: 1,165: 2,181,185,197,202,225,257,266,267,281,341,353,354,358. And blue dyes such as 364, 365, and 368.

  The content of the colorant in the total mass of the ink is usually 1 to 30%, preferably 1 to 10%, more preferably 2 to 7%.

  The colorant has an average particle size (D50) of usually 50 nm to 150 nm, preferably 60 nm to 120 nm. In the present specification, the average particle diameter means an average particle diameter of particles measured by a laser light scattering method.

The colorant is prepared by using a colorant and the first polymer or a colorant and the first polymer and the second polymer to prepare a dispersion of the colorant, and then using the dispersion for the preparation of the ink. Is preferred. Known methods can be used for preparing the dispersion.
As an example, when the polymer does not dissolve in water, a phase inversion emulsification method can be used. That is, the first polymer is dissolved in an organic solvent such as 2-butanone, and an aqueous solution of a neutralizing agent is added to prepare an emulsion. A coloring agent is added to the obtained emulsion to carry out a dispersion treatment. By distilling off the organic solvent and a portion of the water under reduced pressure from the liquid thus obtained, a target colorant dispersion can be obtained.
Examples of the dispersion treatment include a method in which the colorant and the polymer are dispersed in a sand mill (bead mill), roll mill, ball mill, paint shaker, ultrasonic disperser, microfluidizer, or the like. For example, when a sand mill is used, beads having a particle size of about 0.01 mm to 1 mm can be used, and the dispersion treatment can be performed by appropriately setting the filling rate of the beads.
Operations such as filtration and / or centrifugation can be performed on the dispersion obtained as described above. By this operation, the size of the particles contained in the dispersion can be made uniform.

  The ink may contain an ink preparation together with a colorant dispersion. Examples of the ink preparation agent include a water-soluble organic solvent, a preservative, a fungicide, a pH adjuster, a chelating reagent, a rust preventive, a water-soluble ultraviolet absorber, an antioxidant, a surfactant, a wax and the like.

  Examples of the water-soluble organic solvent include C1-C6 alkanol having one hydroxy group such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol or tertiary butanol; N, N-dimethylformamide or Amides such as N, N-dimethylacetamide; lactams such as 2-pyrrolidone, N-methyl-2-pyrrolidone or N-methylpyrrolidin-2-one; 1,3-dimethylimidazolidin-2-one or 1,3 Cyclic urea such as -dimethylhexahydropyrimid-2-one; ketone or keto alcohol such as acetone, 2-methyl-2-hydroxypentan-4-one and ethylene carbonate; cyclic ether such as tetrahydrofuran and dioxane; ethylene glycol , Diethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butylene glycol, 1,4-butylene glycol, 1,2-hexylene glycol, 1,6-hexylene glycol, diethylene glycol, triethylene glycol, tetra Mono-, oligo- or polyalkylene glycols or thioglycols having C2-C6 alkylene units, such as ethylene glycol, dipropylene glycol, polyethylene glycol or polypropylene glycol having a molecular weight of 400 or more, thiodiglycol or dithiodiglycol; glycerin, diglycerin , Hexane-1,2,6-triol, polyol (triol) such as trimethylolpropane; ethylene glycol monomethyl ether, ethylene glycol monoethyl ether Diethylene glycol monoethyl ether, diethylene glycol monobutyl ether (butyl carbitol), triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol monoallyl ether, ethylene glycol monoisopropyl ether, diethylene glycol monomethyl ether, propylene glycol monopropyl ether, triethylene glycol And C1-C4 alkyl ethers of polyhydric alcohols such as ethylene glycol monobutyl ether; γ-butyrolactone or dimethyl sulfoxide;

  Examples of preservatives include, for example, organic sulfur, organic nitrogen sulfur, organic halogen, haloaryl sulfone, iodopropargyl, haloalkylthio, nitrile, pyridine, 8-oxyquinoline, benzothiazole, isothiazoline, dithiol, pyridine oxide, nitropropane , Organic tin, phenol, quaternary ammonium salt, triazine, thiazine, anilide, adamantane, dithiocarbamate, brominated indanone, benzyl bromacetate, inorganic salts and the like, and derivatives thereof. Further, Proxel GXL (S) and Proxel XL-2 (S) manufactured by Arch Chemical Co., Ltd. may also be used.

  Specific examples of the fungicide include sodium dehydroacetate, sodium benzoate, sodium pyridinethione-1-oxide, ethyl p-hydroxybenzoate, 1,2-benzisothiazolin-3-one and salts thereof. .

  As the pH adjuster, a substance capable of controlling the pH of the ink to usually 5 to 11, preferably 7 to 10 can be used. Specific examples thereof include, for example, the neutralizing agent described above; alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium hydrogen carbonate and potassium carbonate; alkali metal salts of organic acids such as sodium silicate and potassium acetate; And an inorganic base such as disodium phosphate; and the like.

  Specific examples of the chelating reagent include, for example, disodium ethylenediaminetetraacetate, sodium nitrilotriacetate, sodium hydroxyethylethylenediaminetriacetate, sodium diethylenetriaminepentaacetate, and sodium uracildiacetate.

  Specific examples of the rust inhibitor include, for example, acid sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrite, pentaerythritol tetranitrate, and dicyclohexylammonium nitrite.

  Examples of the water-soluble ultraviolet absorber include, for example, sulfonated compounds such as benzophenone, benzotriazole, salicylic acid, cinnamic acid, and triazine, and derivatives thereof.

  As an example of the antioxidant, for example, an antifading agent can be used. Examples of the anti-fading agent include compounds such as hydroquinone, alkoxyphenol, dialkoxyphenol, phenol, aniline, amine, indane, chroman, alkoxyaniline, and heterocycle, and derivatives thereof.

  Examples of the surfactant include known surfactants such as, for example, anions, cations, nonions, amphoteric, silicone-based, and fluorine-based surfactants.

  Examples of anionic surfactants include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether sulfates, N-acyl amino acids or salts thereof, N-acylmethyl taurine salts, Alkyl sulfate polyoxyalkyl ether sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate, lauryl alcohol sulfate, alkylphenol phosphate, alkyl phosphate, alkylaryl sulfone Acid salts, diethylsulfosuccinate, diethylhexylsulfosuccinate, dioctylsulfosuccinate and the like. As the anionic surfactant, various kinds of products can be easily purchased from, for example, Daiichi Kogyo Seiyaku Co., Ltd. or the like.

  Examples of the cationic surfactant include a 2-vinylpyridine derivative and a poly-4-vinylpyridine derivative.

  Nonionic surfactants include ethers such as polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, and polyoxyethylene alkyl ether; Ester systems such as polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, polyoxyethylene monooleate, polyoxyethylene stearate; 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl -1-hexyne-3-acetylene glycol (alcohol) -based ol; polyglycol ether and the like. As the nonionic surfactant, various kinds of products can be easily purchased, for example, as Surfynol series and Olfin series of Nissin Chemical Co., Ltd.

  Examples of the amphoteric surfactant include betaine lauryl dimethylaminoacetate, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut fatty acid amide propyldimethylaminoacetate betaine, polyoctyl polyaminoethyl glycine, and imidazoline derivatives. Is mentioned.

Examples of the silicone-based surfactant include polyether-modified siloxane and polyether-modified polydimethylsiloxane. Examples include Dynol 960 and Dynol 980 manufactured by Air Products, Sylface SAG001, Sylface SAG002, Sylface SAG003, Sylface SAG005, Sylface SAG503A, Sylface SAG008, and Sylface SAG009 manufactured by Nissin Chemical Co., Ltd. , Sylface SAG010, and BYK-345, BYK-347, BYK-348, BYK-349, BYK-3455 manufactured by BYK-Chemie, and various types of products can be easily purchased.
Further, as the silicone-based surfactant, a compound represented by the following formula (2) is also preferably exemplified.

  In the formula (2), a is an integer of 0 to 5, b is an integer of 1 to 5, c is an integer of 3 to 30, and d is an integer of 0 to 20.

Examples of the fluorine-based surfactant include a perfluoroalkylsulfonic acid compound, a perfluoroalkylcarboxylic acid-based compound, a perfluoroalkylphosphate compound, a perfluoroalkylethylene oxide adduct, and a perfluoroalkylether group having a side chain. And the like. Various types of fluorine surfactants can be easily purchased from, for example, DuPont, Omnova, DIC, and Big Chemie.
The ink can be microfiltered. When performing microfiltration, a membrane filter and / or glass filter paper or the like can be used. When the ink is used for ink-jet recording, it is preferable to perform microfiltration. The pore size of a filter or the like when performing microfiltration is usually 0.5 μm to 20 μm, preferably 0.5 μm to 10 μm.

  The surface tension of the ink is usually 10 to 50 mN / m, preferably 20 to 40 mN / m. The viscosity of the ink is usually 30 mPa · s or less, preferably 20 mPa · s or less. The lower limit is preferably 0.1 mPa · s or more.

When the ink is used for inkjet recording, it is preferable to remove inorganic impurities in the ink. Examples of the inorganic impurities include chlorides (for example, sodium chloride) and sulfates (for example, sodium sulfate) of metal cations. The content of the inorganic impurities is preferably 1% or less based on the total mass of the colorant contained in the ink. , The lower limit can be below the detection limit of the analytical instrument.
As a method for removing inorganic impurities, for example, a method using a reverse osmosis membrane; a method for suspending and purifying a colorant in a mixed solvent of a water-soluble organic solvent and water; and a method for adsorbing inorganic impurities with an ion exchange resin And the like.

  The ink can be used as an aqueous ink in various recording and printing fields. For example, it is suitable for writing ink, printing ink, information recording ink, textile printing, and the like. In particular, it is preferably used for inkjet recording, and is suitably used in the inkjet recording method described below.

The inkjet recording method is a method of performing recording by ejecting droplets of the ink according to a recording signal and attaching the droplets to a recording medium.
There are no particular restrictions on the ink nozzles used for recording, the ejection method, and the like, and they can be appropriately selected according to the purpose.
As the ejection method, for example, a charge control method for ejecting ink using electrostatic attraction; a drop-on-demand method using a vibration pressure of a piezo element (also referred to as a pressure pulse method); Acoustic ink-jet system in which the change ink is irradiated and the ink is discharged using the radiation pressure; thermal ink-jet system in which the ink is heated to form bubbles and the generated pressure is used;
The recording medium refers to a substance to which the ink can adhere. The material is not limited as long as the ink can be attached. Among such recording media, for example, coated papers such as lightly coated paper, art paper, coated paper, matte paper, cast paper, etc .; plain paper, gravure printing and offset printing each having no ink receiving layer Media used for etc .; inkjet-only paper, inkjet-only film, glossy paper, glossy film or the like having an ink-receiving layer; fiber or cloth (cellulose, nylon, wool, etc.); leather; . Recording media to which the ink has been attached are also included in the scope of the present invention.

  When recording on a recording medium by the ink jet recording method, an ink jet printer having a container containing the ink can be used. An inkjet printer having a container containing the ink is also included in the scope of the present invention.

  Regarding all the components and configurations described above, a combination of preferable components is more preferable, and a combination of more preferable components is further preferable. The same applies to combinations of preferable and more preferable ones, more preferable and further preferable ones, and the like.

The effects obtained by the present invention include the following effects. That is, the ink of the present invention has excellent storage stability and also has excellent fixability of images recorded on various recording media. The ink of the present invention does not cause a mottling phenomenon even when recorded on various recording media, so that a high-quality recorded image can be obtained.
In addition, when ink-jet recording is performed using the ink of the present invention, a recorded image having high roundness of ink dots when adhered to a recording medium, having smoothness, and not impairing glossiness can be obtained.
Furthermore, the image recorded with the ink of the present invention is excellent in various fastnesses such as water resistance, light resistance, heat resistance, and oxidation gas (eg, ozone gas resistance).

  EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to the following Examples. In the text, “parts” and “%” are based on mass unless otherwise specified. In addition, all operations such as each synthesis reaction and crystallization were performed with stirring unless otherwise specified.

[Synthesis Example 1]: Preparation of first polymer.
By pursuing Synthesis Example 3 of WO 2013/115071, 138.2 g of a first polymer having an acid value of 104 KOH mg / g was prepared.
[Synthesis Example 2]: Preparation of second polymer (neutralized solution).
As a second polymer, Joncryl 678 manufactured by BASF was used.
25 parts of Joncryl 678 (Mw: 8500) and 14.3 parts of triethanolamine were dissolved in 60.7 parts of ion-exchanged water and stirred for 1 hour to prepare a neutralized solution of the second polymer.
[Synthesis Example 3]: Preparation of third polymer.
By pursuing the method described in Preparation Example 4 of WO 2015/147192, an emulsion of a third polymer having an acid value of 6 KOH mg / g, a Tg of 0 ° C, and a solid content of 25% was prepared.

[Synthesis Example 4]: Preparation of first polymer dispersion 1
6 parts of the first polymer was dissolved in 30 parts of 2-butanone to form a uniform solution. To this solution, a solution prepared by dissolving 0.44 g of sodium hydroxide in 41 parts of ion-exchanged water was added and stirred for 1 hour to prepare an emulsified solution in which the polymer dispersant was dissolved. C. was added to the obtained emulsified solution. I. Pigment Blue 15: 3 (Cyanine Blue A220J manufactured by Dainichi Seika Kogyo Co., Ltd.) was added, and a dispersion treatment was performed with a sand grinder at 1500 rpm for 15 hours. After 100 parts of ion-exchanged water was dropped into the obtained liquid, the liquid was filtered to remove dispersion beads. From the obtained filtrate, 2-butanone and water were distilled off under reduced pressure by an evaporator to obtain a cyan dispersion having a pigment solid content of 12%. The solid content in the aqueous solution was measured by a dry weight method using MS-70 manufactured by A & D Corporation. The obtained colored dispersion is referred to as “first polymer dispersion 1”.

[Synthesis Example 5]: Preparation of second polymer dispersion liquid 1
To 45 parts of the second polymer neutralized solution and 67.5 parts of ion-exchanged water, C.I. I. Pigment Blue 15: 3 (Cyanine Blue A220J manufactured by Dainichi Seika Kogyo Co., Ltd.) was added, and the mixture was dispersed with a sand grinder at 1500 rpm for 20 hours. After 150 parts of ion-exchanged water was dropped into the obtained liquid, the liquid was filtered to remove beads for dispersion, whereby a dispersion having a solid content of 18.2% was obtained. The resulting dispersion is referred to as “second polymer dispersion 1”.

[Examples 1 to 3] Preparation of ink.
Each component described in Table 2 below was mixed to obtain a liquid. The inks of Examples 1 to 3 were obtained by filtering the obtained liquid through a 3 μm membrane filter. Each ink was adjusted so that the pigment concentration was 5%.

[Comparative Examples 1 to 3]
Comparative inks of Comparative Examples 1 to 3 were prepared in the same manner as in Examples 1 to 3 except that the components shown in Table 2 below were used.
The following evaluation tests were performed using the obtained inks of Examples and Comparative Examples.

[Fixation test]
Using an ink jet printer (trade name: PX205) manufactured by Seiko Epson Corporation, 100% Duty images of the inks of Examples and Comparative Examples were solid-printed on OK Topcoat (manufactured by Oji Paper). A test piece was obtained by drying the obtained image at room temperature for 24 hours.
The solid printing surface of the test piece and new OK top coated paper were overlaid. A load of 500 g was reciprocated 10 times on the two sheets of paper. The two sheets of paper were peeled off, and the reflection density (Dk value) of the solid printed surface of the test piece was measured with a densitometer manufactured by X-rite, trade name Spectro Eye. The reflection density was measured under the conditions that the observation light source was D50, the observation field of view was 2 °, and the density was ANSI A. The change in the reflection density before and after the test was calculated as the residual rate (%) by the following formula, and evaluated based on the following criteria. The evaluation results are shown in Table 3 below.
Residual rate (%) = (print density after test) / (print density before test) × 100.

[Evaluation criteria for fixability]
A: The residual ratio is 95% or more.
B: The residual ratio is 90% or more and less than 95%.
C: Residual rate is less than 90%.

[Storage stability test]
50 ml of each ink of the above Examples and Comparative Examples was collected in a sample bottle, sealed, and stored in a 60 ° C. constant temperature bath for one week. After returning each ink after storage to room temperature of about 25 ° C., the viscosity of each ink was measured, and the rate of change (%) in viscosity before and after storage was evaluated according to the following criteria. The results are shown in Table 3 below. The viscosity was measured using a rotary viscometer (R115 type viscometer, manufactured by Toki Sangyo Co., Ltd.).

[Evaluation criteria for storage stability]
A: The change rate is within ± 0.5%.
B: The change rate is more than ± 0.5% and within 1%.
C: Change rate is greater than ± 1%.

  As is clear from the above results, in each of Comparative Examples containing only two of the first to third polymers, the fixing property and / or the storage stability were evaluated as “C”. On the other hand, in each of the examples, the evaluation was "A", and the fixing property and the storage stability were extremely excellent.

  The ink of the present invention is excellent in fixability and storage stability, and therefore, is extremely suitable for various recording applications, particularly inkjet recording applications.

Claims (7)

A colorant, water, and an ink containing a first polymer, a second polymer, and a third polymer, each having a different monomer configuration, wherein the monomers constituting the first to third polymers are methacrylic acid derivatives, An acrylic acid derivative, and an ink that is a monomer selected from a styrene derivative ,
The first polymer is an AB block polymer composed of two blocks, an A block and a B block, wherein the A block is composed of aralkyl methacrylate or aralkyl methacrylate and methacrylic acid, and the B block is An AB block polymer composed of alkyl methacrylate and methacrylic acid, and having a weight average molecular weight of 10,000 to 60,000,
The monomer constituting the second polymer is a monomer selected from at least one of each of an acrylic acid derivative and a styrene derivative,
An ink in which the monomers constituting the third polymer are two kinds of alkyl methacrylate, methacrylic acid, and alkyl acrylate . The ink of claim 1 , wherein the first polymer is a colorant dispersant.   The ink according to claim 1, wherein the monomer selected from the styrene derivative is a monomer selected from styrene and α-methylstyrene.   The ink according to claim 1, wherein the monomer selected from the acrylic acid derivative is a monomer selected from the group consisting of aralkyl acrylate, alkyl acrylate, and acrylic acid. An ink jet recording method for performing recording by discharging the ink droplets according to any one of claims 1 to 4 in accordance with a recording signal and attaching the droplets to a recording medium. A recording medium to which the ink according to claim 1 is adhered. An ink jet printer having a container containing the ink according to claim 1 .