JP2021155716A - Ink, and inkjet recording method - Google Patents

Abstract

To provide an ink that enables the provision of printed matter having no uneven coating and an excellent scratch resistance, an inkjet recording method using the ink, and a recording media having the ink adhered.SOLUTION: Provided is an ink that contains a water-insoluble colorant, a dispersant, water, a nonionic surfactant having a HLB value of more than 7.9 and 20.0 or less, and a resin having a weight average molecular weight of 4500 to 500,000. Here, if the nonionic surfactant and the resin having a weight average molecular weight of 4500 to 500,000 are both siloxane compound, they cannot be the same compound.SELECTED DRAWING: None

Description

An object of the present invention is to provide an ink, an inkjet recording method using the ink, and a recording medium to which the ink adheres.

The recording method using an inkjet printer, which is one of the typical methods among various color recording methods, generates small droplets of ink and attaches them to a recording medium such as paper for recording. In recent years, the demand for industrial use has increased, and it is required to support various recording media.

In particular, for ink non-absorbent media typified by film (hereinafter, may be referred to as “non-absorbent media”), solvent ink containing an organic solvent as a main component and UV containing a polymerizable monomer are contained. The development of inks, etc. has been promoted. However, these inks have many safety problems such as VOC and skin sensitization, and their uses are limited.

Therefore, as described in Patent Documents 1 and 2, water-based inks capable of printing images with high durability even on non-absorbent media by adding polymer fine particles or the like while containing water as a main component. Development is becoming more active.

However, even if the inks obtained in these proposals are used, the scratch resistance to non-absorbent media such as PET (polyethylene terephthalate) and PP (polypropylene) is insufficient, and improvement is required.

Japanese Patent No. 5504890 Japanese Patent No. 6295825

An object of the present invention is to provide an ink capable of providing a printed matter having an excellent balance between coating unevenness and scratch resistance, an inkjet recording method using the ink, and a recording medium to which the ink is attached.

As a result of intensive research to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by the ink, recording medium and recording method described in the following [1] to [5]. The present invention has been completed.

That is, the present invention relates to the following [1] to [5].
[1]
An ink containing a water-insoluble colorant, a dispersant, water, a nonionic surfactant having an HLB value of more than 7.9 and 20.0 or less, and a resin having a weight average molecular weight of 4500 to 500000. However, if both the nonionic surfactant and the resin having a weight average molecular weight of 4500 to 500000 are siloxane compounds, they may not be the same compound.
[2]
The ink according to [1], which further contains glycol ethers.
[3]
The ink according to [2], wherein the glycol ethers are alkylene glycol monoalkyl ethers.
[4]
A recording medium to which the ink according to any one of [1] to [3] is attached.
[5]
An inkjet recording method for recording by ejecting droplets of the ink according to any one of [1] to [3] from an inkjet printer and adhering them to a recording medium.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an ink capable of providing a printed matter having an excellent balance between coating unevenness and scratch resistance, an inkjet recording method using the ink, and a recording medium colored by the ink.

[Water-insoluble colorant]
The above colorant is not particularly limited as long as it is a water-insoluble colorant. For example, known pigments, disperse dyes, solvent dyes and the like can be used. As used herein, the water-insoluble colorant means a colorant having a solubility in 1 liter of water at 25 ° C. of usually 5 g or less, preferably 3 g or less, more preferably 1 g or less, still more preferably 0.5 g or less. The lower limit of solubility includes 0 g.
Unless otherwise specified, "water-insoluble colorants" are hereinafter referred to as "colorants".
Colorants can be used in combination. The types of colorants contained in the ink are usually 3 or more, preferably 3 to 5 for black ink, and usually 3 for, preferably 2 or 1 for color inks other than black ink. .. However, when the black ink contains carbon black as a colorant, the type of the colorant is preferably two or one. In the present specification, the color ink means a colored ink other than the black ink (for example, ink of each color such as yellow, magenta, cyan, red, orange, brown, violet, blue, green).
Further, among pigments, disperse dyes, and solvent dyes, pigments are preferable. Examples of the pigment include an inorganic pigment, an organic pigment, and an extender pigment.

Examples of the inorganic pigment include carbon black, titanium oxide, metal oxide, hydroxide, sulfide, ferrocyanide, metal chloride and the like.

As the colorant contained in the black ink, carbon black such as thermal black, acetylene black, oil furnace black, gas furnace black, lamp black, gas black, and channel black is preferable. Specific examples of carbon black include, for example, the Raven series manufactured by Columbia Carbon Co., Ltd .; the Monarch series, Regal series, and Mogul series manufactured by Cabot Corporation; the ColorBlack series, Printex series, and SpecIalBlack series manufactured by Orion Engineered Carbons Co., Ltd. And Neurox series; MA series, MCF series, No. 25, No. 33, No. 40, No. 47, No. 52, No. 900 and No. 2300 and the like can be mentioned.

Examples of organic pigments include various pigments such as azo, diazo, phthalocyanine, quinacridone, isoindoleone, dioxazine, perylene, perylene, thioindigo, anthoraquinone, and quinophthalone.

Specific examples of organic pigments include, for example, 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, Yellows such as 139, 150, 151, 154, 155, 180, 185, 193, 199, 202, 213; C.I. 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, Reds such as 254, 255, 257, 260, 264, 272; C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15: 4, 15: 6, 16, 22, 25, 60, 66, 80, etc. Blue; I. Pigment Violet 19, 23, 29, 37, 38, 50, etc. Violet; C.I. I. Pigment Orange 13, 16, 68, 69, 71, 73, etc. Orange; C.I. I. Greens such as Pigment Green 7, 36, 54; C.I. I. Pigment Black 1 and other black pigments of each color can be mentioned.

Examples of the extender pigment include silica, calcium carbonate, talc, clay, barium sulfate, and white carbon. The extender pigment is often used in combination with other colorants.

Examples of the disperse dye include known disperse dyes. Among them, C.I. I. Dyes selected from Dispers are preferred. Specific examples thereof include, for example, C.I. I. Dispers 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 , 163, 165, 180, 183, 186, 198, 200, 211, 224, 226, 227, 231, 237, etc. Yellow; I. Dispers Red 60, 73, 88, 91, 92, 111, 127, 131, 143, 145, 146, 152, 153, 154, 167, 179, 191, 192, 206, 221, 258, 283, etc. Red; C .. I. Dispers Orange 9, 25, 29, 30, 31, 32, 37, 38, 42, 44, 45, 53, 54, 55, 56, 61, 71, 73, 76, 80, 96, 97, etc. Orange; C .. I. Dispers Violet 25, 27, 28, 54, 57, 60, 73, 77, 79, 79: 1 etc. Violet; C.I. 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, Dispersive dyes of each color of blue such as 358, 364, 365, 368 and the like can be mentioned.

The content of the colorant with respect to the total mass of the ink is usually 1 to 30%, preferably 1 to 10%, and more preferably 2 to 7%.
The average particle size of the colorant is usually 50 nm to 250 nm, preferably 60 nm to 200 nm. In the present specification, the average particle size means the average particle size of particles measured by using a laser light scattering method.

[Dispersant]
The above-mentioned dispersant is not particularly limited, and a known dispersant can be used. The dispersant is used for the purpose of dispersing the water-insoluble colorant in the ink. As the dispersant, a polymer dispersant such as a resin is generally used. Examples of such resins include polyvinyl alcohol, cellulose derivatives, polyethylene oxide, polypropylene oxide, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, itaconic acid monoester, maleic acid, maleic acid monoester, fumaric acid, and the like. Ionic monomers such as fumaric acid monoester, vinyl sulfonic acid, sulfoethyl methacrylate, sulfopropyl methacrylate, α, β-unsaturated monomer of sulfonated vinyl naphthalene, styrene, styrene derivative, vinyl naphthalene, vinyl naphthalene derivative, α, β -Derived from aliphatic alcohol esters of ethylenically unsaturated carboxylic acids, acrylic nitriles, vinylidene chloride, vinyl acetate, vinyl chloride, acrylamide, methacrylic acid, hydroxyethyl methacrylate, hydroxypropyl methacrylate, glycidyl methacrylate, N-butoxymethyl acrylamide, etc. Examples include polymers.

Examples of the above-mentioned dispersant include the same as the AB block polymer disclosed in Gazette 2013/115071, including preferable ones. The same applies to the method for producing the AB block polymer and the like.
As an example of the dispersant (AB block polymer) disclosed in WO 2013/115071, for example, the monomers constituting the A polymer are (meth) acrylic acid and linear or branched C4 alkyl. One or more kinds of monomers selected from (meth) acrylates, and the monomers constituting the B polymer are benzyl methacrylate and / or benzyl acrylate. In this specification, the terms "(meth) acrylic" and "(meth) acrylate" are used to mean both "acrylic, methacryl" and "acrylate, methacrylate", respectively.
The monomer constituting the A block is preferably one or more kinds of monomers selected from methacrylic acid and n-butyl methacrylate, and it is particularly preferable to use these two kinds of monomers in combination.
The monomer constituting the B block is preferably benzyl methacrylate.
Specific examples thereof include the block copolymers disclosed in Synthesis Examples 3 to 8 of the above-mentioned internationally available gusset.

As the styrene- (meth) acrylic polymer, the Joncryl series manufactured by BASF is preferable.

The acid value of the dispersant is usually 90-200 mgKOH / g, preferably 100-150 mgKOH / g, more preferably 100-120 mgKOH / g.
The mass average molecular weight of the dispersant is usually 1000 to 60000, preferably 1000 to 40,000, more preferably 1500 to 30000, and even more preferably 2000 to 25000.
The PDI (mass average molecular weight / number average molecular weight) of the dispersant is about 1.29 to 1.49.
By setting the range as described above, the dispersibility and storage stability can be improved.
Examples of the neutralizing agent include ammonia, alkali metal hydroxides, alkaline earth metal hydroxides, aliphatic amine compounds and alkanolamine compounds. Ammonia and alkali metal hydroxides are preferred, with ammonia particularly preferred.
The amount of the neutralizing agent used is not particularly limited. As a guideline, the degree of neutralization is usually 30 to 300%, more preferably 50 to 200%, with 100% neutralization when neutralized with the theoretical equivalent amount of the acid value of the dispersant.

The above dispersant can be used in a mixed state with a water-insoluble colorant. It can also be used as a state in which the surface of the water-insoluble colorant is coated with a dispersant. Moreover, both of these can be used together. As used herein, the term "coating" means both a state in which the entire surface of the water-insoluble colorant is covered with a dispersant and a state in which a part of the surface of the water-insoluble colorant is covered with the dispersant. do.
When a dispersant is used, the ratio of the total mass of the dispersant to the total mass of the water-insoluble colorant is usually 0.1-1.0, preferably 0.1-0.6, more preferably 0.2-. It is 0.5.

[Nonionic surfactant having an HLB value greater than 7.9 and less than or equal to 20.0]
The nonionic surfactant having an HLB value of more than 7.9 and 20.0 or less is not particularly limited as long as it is a nonionic surfactant having an HLB value of more than 7.9 and 20.0 or less. However, for example, "general-purpose nonionic surfactant", "silicon-based nonionic surfactant", and "fluorine-based nonionic surfactant" described later can be mentioned. Compared with ionic surfactants, non-ionic surfactants are less likely to cause intermolecular interactions such as ionic bonds and are more likely to lower surface tension. Therefore, it is easy to get wet on the media, and uneven coating of printed matter is unlikely to occur.

Examples of the above-mentioned "general-purpose nonionic surfactant" include polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene tridecyl ether, and polyoxyethylene oleyl ether. Polyoxyalkylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene alkyl ether; polyoxyethylene oleic acid ester, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquiole Polyoxyalkylene acylate such as ate, polyoxyethylene monooleate, polyoxyethylene stearate; polyoxyethylene aryl ether such as polyoxyalkylene styrene phenyl ether; 2,4,7,9-tetramethyl-5- Acetylene glycol (alcohol) type such as decine-4,7-diol, 3,6-dimethyl-4-octin-3,6-diol, 3,5-dimethyl-1-hexin-3-ol; polyglycol ether type And so on. Nonionic surfactants include, for example, Surfinol series and Orphine series such as Surfinol 465 of Nissin Chemical Co., Ltd., Emargen series of Kao Co., Ltd., and Newcol series of Nippon Emulsifier Co., Ltd. (for example, polyoxyethylene alkyl ether). Obtained as a certain Newcol NT-5, 12), Neugen series of Daiichi Kogyo Seiyaku Co., Ltd. (for example, Neugen TDX-50 which is a polyoxyalkylene tridecyl ether, Neugen EA197D which is a polyoxyethylene styrene phenyl ether, etc. can do.

Examples of the above-mentioned "silicon-based nonionic surfactant" include siloxane compounds such as polyether-modified siloxane and polyether-modified polydimethylsiloxane. As an example, Dynol 960 and Dynol 980 manufactured by Air Products & Chemicals, Silface SAG001, Silface SAG002, Silface SAG003, Silface SAG005, Silface SAG503A, Silface SAG008, Silface SAG009 manufactured by Nisshin Kagaku Co., Ltd. , Silface SAG010, and BYK-345, BYK-347, BYK-348, BYK-349, BYK-3455, BYK-LP-X23288, BYK-3451 (also known as BYKLPX 23347), BYK-3450 (manufactured by Big Chemie). Another name: BYKLPX 23289) and the like can be obtained.

Examples of the above-mentioned "fluorine-based nonionic surfactant" include a perfluoroalkyl sulfonic acid compound, a perfluoroalkyl carboxylic acid compound, a perfluoroalkyl phosphate ester compound, a perfluoroalkyl ethylene oxide adduct, and a per. Examples thereof include a polyoxyalkylene ether polymer compound having a fluoroalkyl ether group in the side chain. The fluorine-based surfactant can be obtained from, for example, The Chemours Company, DuPont Company, Omniova Company, DIC Corporation, Big Chemours Company, and the like. Specific examples thereof include Capstone FS-30 manufactured by The Chemours Company.

The HLB value of the above-mentioned nonionic surfactant is larger than 7.9 and 20.0 or less, preferably 8.0 to 18.0, and more preferably 9.0 to 18.0. In the present specification, the HLB value is described by rounding off the second decimal place and up to the first decimal place.
It can also be obtained as an actually measured value by an experiment. As for the method, a known method can be used. As an example, for example, the method by the Griffin method described in the Gazette of International Publication No. 2017/159685 can be mentioned. The HLB value can be calculated by the following formula (1). The "HLB value" described in the present specification means an HLB value calculated by using the above-mentioned Griffin method when the structure of the compound to be used is clearly known.

HLB value = 20 × (total molecular weight of hydrophilic part) ÷ (molecular weight of material) Equation (1)

Further, when the HLB value is described in the catalog or the like of the manufacturer or the distributor, the value can also be used.
When the above HLB value does not have a digit after the decimal point, the first digit after the decimal point is regarded as "zero" and the first digit after the decimal point is described.

[Resin with a weight average molecular weight of 4500 to 500000]
The role of the resin generally used in water-based inkjet inks is used for the purpose of imparting adhesion to a base material and resistance to a printed surface. The structures of the resins used are diverse, such as acrylic, styrene-acrylic, urethane, olefin, and paraffin, but in common, the higher the molecular weight of the resin, the higher the strength of the film formed. The strength of the film is derived from the glass transition point of the resin, and is caused by the increase in the glass transition point of the resin as the molecular weight increases. Therefore, the higher the molecular weight of the resin used, the higher the strength of the printed surface. Examples of the resin having a weight average molecular weight of 4500 to 500,000 include Evafar HA-15 manufactured by Nicca Chemical Co., Ltd. and NeoCryl A-655 manufactured by DSM Coating Resin. The weight average molecular weight of the resin is preferably 5000 to 400000, more preferably 6500 to 300,000. Further, as an example of the resin, a siloxane compound described later can also be mentioned.

[Siloxane compound]
Siloxane is a compound having silicon and oxygen as skeletons, and is known as a general term for compounds having a Si—O—Si bond. The siloxane compound corresponds to a compound having a siloxane structure that exhibits a property of improving the slipperiness of the coating film surface. Further, the reason why a long main chain siloxane skeleton is effective is the influence of film formation on the ink surface. The longer the siloxane skeleton of the main chain, the higher the hydrophobicity, and the siloxane compound floats on the surface after the ink has dried, forming a microfilm. Since this micro film acts as a so-called lubricant, it is considered that the coefficient of friction is lowered and slipperiness is obtained. A siloxane compound having a short siloxane skeleton and a molecular weight of less than 4500 has weak siloxane bond linearity and is prone to hydrogen bonds, resulting in weak hydrophobic performance. Therefore, it is said that slipperiness is hard to be exhibited. Examples of the siloxane compound include dimethylsiloxane, methylsiloxane, silanol, etc. Among them, dimethylsiloxane has high hydrophobicity and easily forms a silicon film on the ink surface in the drying step, so that slipperiness is more exhibited. Since the silicon-based surfactant described above has a short main chain and does not exhibit a slip effect, the difference from this siloxane compound is explained by the weight average molecular weight. Examples of such a siloxane compound include BYK-3760 manufactured by Big Chemie, TEGO Glide 490 manufactured by Evonik, and DOWNSIL IE-7170 manufactured by Toray Dau. As the siloxane compound, a compound having a weight average molecular weight in this range is preferable. When the ink contains such a compound, it is possible to obtain a printed image having less uneven coating and good scratch resistance.
However, if both the nonionic surfactant and the resin having a weight average molecular weight of 4500 to 500000 are siloxane compounds, they may not be the same compound.

[water]
The ink is a water-based ink containing water. As the water contained in the ink, water having a low content of impurities such as metal ions, that is, ion-exchanged water, distilled water and the like is preferable. Such water can be prepared by known methods.

The ink may further contain a solvent. Examples of the solvent include C1-C6 alkanol having one hydroxy group such as methanol, ethanol, propanol, isopropanol, butanol, isobutanol, second butanol or third butanol; N, N-dimethylformamide or N, Amidos such as N-dimethylacetamide; lactams such as 2-pyrrolidone, N-methyl-2-pyrrolidone or N-methylpyrrolidin-2-one; 1,3-dimethylimidazolidine-2-one or 1,3-dimethyl Cyclic urea such as hexahydropyrimido-2-one; ketone or ketoalcohol such as acetone, 2-methyl-2-hydroxypentane-4-one, ethylene carbonate; cyclic ether such as tetrahydrofuran, 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 , Tetraethylene glycol, dipropylene glycol, polyethylene glycol or polypropylene glycol having a molecular weight of 400 or more, thiodiglycol or dithiodiglycol, etc., mono, oligo or polyalkylene glycol or thioglycol having C2-C6 alkylene unit; glycerin, Polyols such as diglycerin, hexane-1,2,6-triol, trimethylpropane (triol); ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl 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 monobutyl ether, tripropylene glycol methyl ether, dimethyl Glyco, dimethyl diglycol, dimethyl triglycol, methyl ethyl diglycol, diethyl diglycol, dibutyl diglycol, dimethyl propylene diglycol, dipropylene glycol methyl ether Glycol ethers such as dipropylene glycol n-propyl ether; γ-butyrolactone or dimethylsulfoxide; C8-C16 (preferably C8-12) alkyl having a hydroxy group and an asyloxy group can be mentioned. Specific examples thereof include texanol.

Among these solvents, it is preferable to include a solvent selected from glycol ethers, a solvent selected from amides, and a solvent selected from alkanediols. Specific examples thereof include diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, methyl ethyl diglycol, diethyl diglycol, dipropylene glycol-n-propyl ether, 1,2-hexanediol, 2-pyrrolidone, 1,2-propylene glycol and the like. Can be mentioned. The ink preferably contains at least glycol ethers among these.
As the glycol ethers, for example, dialkylene glycol monoalkyl ether is preferable; diC2-C3 alkylene glycol mono C1-C4 alkyl ether is more preferable; diC2-C3 alkylene glycol mono C3-C4 alkyl ether is further preferable. Specific examples thereof include diethylene glycol monobutyl ether (butyl diglycol) and dipropylene glycol-n-propyl ether.

The amount of the solvent added is preferably 3% or more and 40% or less, and more preferably 5% or more and 30% or less of the total amount of ink.

The ink may be, for example, an ink preparation agent such as a preservative, a fungicide, a pH adjuster, a chelating reagent, a rust preventive, a water-soluble ultraviolet absorber, an antioxidant, a resin emulsion, or a wax, if necessary. Can be contained. As each of the above-mentioned ink preparations, one type may be used, or two or more types may be used in combination.

Examples of preservatives include organic sulfur-based, organic nitrogen-sulfur-based, organic halogen-based, haloarylsulfone-based, iodopropagil-based, haloalkylthio-based, nitrile-based, pyridine-based, 8-oxyquinolin-based, and benzothiazole-based. , Isothiazolin-based, dithiol-based, pyridine oxide-based, nitropropane-based, organic tin-based, phenol-based, tetraammonium salt-based, triazine-based, thiazine-based, anilide-based, adamantan-based, dithiocarbamate-based, brominated indanone-based, benzyl Examples thereof include bromacetate-based or inorganic salt-based compounds.
Specific examples of commercially available preservatives include Arch Chemical Co., Ltd., trade names Proxel GXL (S), Proxel XL-2 (S), and the like.

Specific examples of the fungicide include sodium dehydroacetate, sodium benzoate, sodium pyridinethioone-1-oxide, p-hydroxybenzoic acid ethyl ester, 1,2-benzisothiazolin-3-one and salts thereof. ..

As the pH adjuster, any substance can be used as long as the pH can be controlled within the above range without adversely affecting the prepared ink. Specific examples thereof include alkanolamines such as diethanolamine, triethanolamine and N-methyldiethanolamine; alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; ammonium hydroxide (water ammonia). Alternatively, alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium hydrogencarbonate, potassium carbonate; alkali metal salts of organic acids such as sodium silicate and potassium acetate; inorganic bases such as disodium phosphate; and the like can be mentioned. ..

Specific examples of the chelating reagent include disodium ethylenediamine tetraacetate, sodium nitrilotriacetic acid, sodium hydroxyethylethylenediamine triacetate, sodium diethylenetriamine pentaacetate, and sodium uracil diacetate.

Specific examples of the rust preventive include acidic sulfite, sodium thiosulfate, ammonium thioglycolate, diisopropylammonium nitrate, pentaerythritol tetranitrate, dicyclohexylammonium nitrate and the like.

Examples of the water-soluble UV absorber include sulfonated benzophenone compounds, benzotriazol compounds, salicylic acid compounds, cinnamic acid compounds and triazine compounds.

As an example of the antioxidant, for example, various organic and metal complex-based anti-fading agents can be used. Examples of the organic anti-fading agent include hydroquinones, alkoxyphenols, dialkoxyphenols, phenols, anilines, amines, indans, chromanes, alkoxyanilines, heterocyclics and the like. ..

The resin emulsion refers to a resin obtained by polymerizing a single or a plurality of constituent monomers dispersed with the above solvent or the like, and examples of the monomers constituting the resin emulsion include styrene derivatives, methacrylic acid derivatives and acrylic acids. Examples include monomers selected from derivatives.
The amount of the resin emulsion added is preferably 0.5% or more and 15% or less, and more preferably 1% or more and 10% or less of the total amount of ink.

As the form of the wax, a wax emulsion dispersed with the solvent or the like is preferable, and an aqueous wax emulsion is particularly preferable. As the wax emulsion, natural wax and chemically synthesized wax can be used. Natural waxes include petroleum-based waxes such as paraffin wax and microcrystallin wax, brown charcoal-based waxes such as Montan wax, plant-based waxes such as carnauba wax and canderia wax, and animal and plant-based waxes such as beeswax and lanolin. Emulsion in which is dispersed in an aqueous medium; as a chemically synthesized wax, a homopolymer wax such as polyethylene, polypropylene, Fishertrop, etc., and a copolymer wax such as ethylene vinyl acetate, ethylene acrylic acid, etc. are dispersed in an aqueous medium. Can be mentioned. These waxes may be used alone or in combination.
The amount of the wax agent added is preferably 0.5% or more and 15% or less, and more preferably 1% or more and 10% or less of the total amount of ink.

Further, if necessary, the ink can be microfiltered. For microfiltration, a membrane filter and / or glass filter paper or the like can be used. When the ink is used for inkjet 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 pH of the ink is preferably pH 5 to 11 and more preferably pH 6 to 10 for the purpose of improving storage stability. The surface tension of the ink is preferably 10 to 50 mN / m, more preferably 20 to 40 mN / m. Further, the viscosity of the ink is preferably 30 mPa · s or less, more preferably 20 mPa · s or less.

When the above ink is used as an ink for inkjet recording, the ink contains a small amount of inorganic impurities such as chloride (for example, sodium chloride) and sulfate (for example, sodium sulfate) of metal cations. Is preferable. Inorganic impurities are often contained in commercially available colorants. The guideline for the content of inorganic impurities is approximately 1% by mass or less with respect to the total mass of the colorant, and the lower limit may be below the detection limit of the analytical instrument, that is, 0%. As a method for obtaining a colorant having a small amount of inorganic impurities, for example, a method using a reverse osmosis membrane; a solid colorant is suspended and stirred in a mixed solvent of C1-C4 alcohol such as methanol and water, and the colorant is filtered and separated. Then, a desalting treatment such as a method of drying; or a method of exchanging and adsorbing inorganic impurities with an ion exchange resin;

The above ink can be used in various recording / printing fields. For example, it is suitable for water-based writing ink, water-based printing ink, information recording ink, printing and the like. In particular, it is preferably used for inkjet recording, and is preferably used in the inkjet recording method described later.

The inkjet recording method of the present invention is a method of recording by ejecting droplets of the ink from an inkjet printer and adhering them to a recording medium. There are no particular restrictions on the ink nozzles and the like used for recording, and they can be appropriately selected according to the purpose.

The inkjet recording method may be any known method. For example, a charge control method that uses electrostatic attraction to eject ink; a drop-on-demand method that uses the vibration pressure of a piezo element (also called a pressure pulse method); it converts an electrical signal into an acoustic beam and irradiates the ink. , An acoustic inkjet method for ejecting ink using the radiation pressure; a thermal inkjet method for heating ink to form bubbles and utilizing the generated pressure, that is, a bubble jet (registered trademark) method; and the like.
The inkjet recording method is a method of ejecting a large number of inks having a low content of colorant in the ink, which is called photo ink, in a small volume; the content of the colorant in the ink is substantially the same hue. A method of improving image quality by using a plurality of inks having different inks; and a method of improving the fixability of a colorant on a recording medium by using a colorless and transparent ink and an ink containing a colorant in combination; included.

Further, for example, a recording medium to which the ink is attached by the above recording method or the like is also included in the scope of the present invention. The recording medium is not particularly limited, but a poorly absorbent recording medium is preferable, and a non-absorbent recording medium is particularly preferable. Examples of the poorly absorbent recording media include plain paper having no ink receiving layer, media used for gravure printing, offset printing, etc., art paper, coated paper, matte paper, cast paper, and the like. Examples of non-absorbent recording media include PET (polyethylene terephthalate), PP (polypropylene), vinyl chloride sheet, glass, rubber and the like.

When recording on a recording medium by the above-mentioned inkjet recording method, for example, a container containing the above-mentioned ink can be set at a predetermined position of an inkjet printer and recorded on the recording medium by the above-mentioned recording method.
In the inkjet recording method, one kind or two or more kinds of inks of the present invention can be used in combination with inks of various colors such as green, blue (or violet) and red (or orange), if necessary.
Ink of each color is injected into each container, and each container can be loaded in a predetermined position of an inkjet printer in the same manner as the container containing the ink and used for inkjet recording.
The industrial inkjet printer has a line-head type inkjet printer configuration for the purpose of increasing the printing speed, and single-pass printing is also preferably performed. With the above ink, it is possible to obtain a printed image having an excellent balance between coating and scratch resistance even under such printing conditions.

All of the above-mentioned components may contain one of them alone, or two or more of them may be used in combination.
Further, with respect to all the above-mentioned matters, the combination of preferable ones is more preferable, and the combination of more preferable ones is further preferable. The same applies to the combination of the preferable one and the more preferable one, the combination of the more preferable one and the more preferable one, and the like.

By using the ink of the present invention, not only inkjet paper, general-purpose plain paper, and non-absorbent recording media, but also non-absorbent recording media have excellent scratch resistance and high image quality without repelling. Recorded images can be obtained. Further, it is possible to obtain an image in which the roundness of the ink dots on the medium is high, the ink dots are smooth, and the glossiness is not impaired. Further, it is possible to obtain recorded images excellent in various robustness such as water resistance, light resistance, heat resistance, and oxidation gas resistance (for example, ozone gas resistance). Further, the storage stability of the ink is also good, and stable ejection performance can be ensured for a long period of time.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to the following Examples. The terms "part" and "%" in the text are based on mass unless otherwise specified.
In addition, each synthetic reaction and operations such as crystallization were carried out under stirring unless otherwise specified.
When it is necessary to measure the solid content of the colorant contained in various liquids, use MS-70 manufactured by A & D Co., Ltd. and use the dry weight method to convert only the colorant. It was calculated as.

[Preparation Example 1]: Preparation of dispersion liquid.
The block copolymer described in Synthesis Example 3 of International Publication No. 2013/115071 was prepared, and 6 parts of the obtained polymer dispersant was dissolved in 30 parts of 2-butanone to prepare a uniform solution. A solution prepared by dissolving 0.68 parts of a 28% aqueous ammonia solution in 53 parts of ion-exchanged water was added to this solution, and the mixture was stirred for 1 hour to prepare an emulsified solution in which the polymer dispersant was dissolved. To this, C.I. I. 20 parts of Pigment Blue 15: 3 (Cyanine Blue A220J manufactured by Dainichiseika Kogyo Co., Ltd.) was added, and dispersion treatment was carried out in a sand grinder under the condition of 1500 rpm for 15 hours. 100 parts of ion-exchanged water was added dropwise to the obtained liquid, and the beads for dispersion were removed by filtration. Then, 2-butanone and water were distilled off under reduced pressure with an evaporator to disperse cyan in a pigment solid content of 11.9%. I got the liquid. The obtained colored dispersion is referred to as "Dp1".

[Examples 1 to 5 and Comparative Examples 1 to 2]: Preparation of ink.
The dispersion liquid "Dp1" obtained above is mixed with each component shown in Table 1 below to obtain an ink, and then filtered through a 3 μm membrane filter to perform Examples 1 to 5 for evaluation test and. Each ink of Comparative Examples 1 and 2 for comparison was obtained. The content of the colorant in the total mass of the inks was adjusted to be 4% for all the inks.

The abbreviations and the like in Table 1 below have the following meanings.
Dp1: Colored dispersion obtained in Preparation Example 1.
BDG: Butyl diglycol.
DPGPE: Dipropylene glycol-n-propyl ether.
NT-3: New call NT-3 (HLB value 7.9).
NT-5: New Call NT-5 (HLB value 10.5).
NT-12: New Call NT-12 (HLB value 12.1).
NF-13: High tenor NF-13 (anionic surfactant, HLB value 13-15).
BYK-3450: Silicon-based surfactant (HLB value 13.8)
BYK-3451: Silicone surfactant (HLB value 9.7)
BYK-3760: Siloxane compound (Mw. 6800).
TG490: TEGO Glide 490, siloxane compound (Mw.31000).

[Evaluation of uneven coating]
The inks of the above Examples and Comparative Examples were applied to the bar coater No. 1 by an automatic coating machine (manufactured by Tester Sangyo Co., Ltd., PI-1210). 3 was used, and the entire surface of the PET sheet (manufactured by Toyobo Co., Ltd., E5100) was coated. Then, the printed matter was obtained by drying in a constant temperature bath at 70 ° C. for 2 minutes.
The obtained test printed matter was visually observed, and coating unevenness was evaluated according to the following criteria. The results are shown in Table 2 below.
D: There is a lot of uneven coating and it is not uniform.
C: Coating unevenness is observed.
B: There seems to be some uneven coating.
A: There is no uneven coating and it is uniform.

[Abrasion resistance test]
The obtained test printed matter was obtained by rubbing the PET films with each other 10 times with a Gakushin tester manufactured by Yasuda Seiki Seisakusho Co., Ltd. under a load of 250 g. The obtained test printed matter was visually observed and the state of the scraped surface was evaluated according to the following criteria. The results are shown in Table 2 below.
D: The scratched surface is completely peeled off, and no ink remains.
C: About half of the scraped surface is peeled off.
B: The scraped surface is scraped and the ink is slightly peeled off.
A: The scratched surface is not scraped and the ink does not come off at all.
The results are shown in Table 2 below.

[Examples 6 to 13 and Comparative Examples 3 to 4]: Preparation of ink.
The dispersion liquid "Dp1" obtained above is mixed with each component shown in Table 3 below to obtain an ink, and then filtered through a 3 μm membrane filter to carry out Examples 6 to 13 for evaluation test and. Each ink of Comparative Examples 3 to 4 for comparison was obtained. The content of the colorant in the total mass of the inks was adjusted to be 4% for all the inks.

The abbreviations and the like in Table 3 below have the following meanings. In addition, among the components in Table 3 below, the numerical values in parentheses are HLB values.
Dp1: Colored dispersion obtained in Preparation Example 1.
BDG: Butyl diglycol.
DPGPE: Dipropylene glycol-n-propyl ether.
NT-5: New Call NT-5.
TDX-50: (Neugen TDX-50).
EA197D: (Neugen EA197D).
SAG503A: (Silface SAG503A).
SF465: Surfinol 465.
FS-30: Capstone FS-30.
TG490: TEGO Glide 490, siloxane compound (Mw.31000).
TG450: TEGO Grid 450, siloxane compound (Mw.4100).
HA-15: Evafar HA-15 (Mw.113000).
A-655: NeoCryl A-655 (Mw.83000).
IE7170: DOWNSIL IE-7170, a siloxane compound (Mw.282799).

Using the inks of Examples 4 to 9 and Comparative Examples 3 to 4 described above, [coating unevenness evaluation] and [scratch resistance test] were carried out in the same manner as described above, respectively. The evaluation results are shown in Table 4 below.

As is clear from the above results, the ink of the example has an evaluation result of "A" or "B", whereas the ink of the comparative example has an evaluation result of "C" or less. became. From these results, it was confirmed that the ink of the example had a better balance between coating unevenness and scratch resistance than the comparative example.

[Inkjet printing test]
Using each of the inks of Examples and Comparative Examples, inkjet recording was performed on PET E5100 (manufactured by Toyobo Co., Ltd.) as a recording medium using an inkjet printer manufactured by Seiko Epson Corporation and a trade name of PX205. As a result, it was confirmed that all the inks were ejected from the inkjet printer without any problem and that inkjet recording was possible on the recording medium.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an ink capable of providing a recorded image having an excellent balance between coating unevenness and scratch resistance, and a recording medium to which the ink adheres. Therefore, the ink of the present invention is extremely useful as various recording inks.

Claims (5)

An ink containing a water-insoluble colorant, a dispersant, water, a nonionic surfactant having an HLB value of more than 7.9 and 20.0 or less, and a resin having a weight average molecular weight of 4500 to 500000. However, if both the nonionic surfactant and the resin having a weight average molecular weight of 4500 to 500000 are siloxane compounds, they may not be the same compound. The ink according to claim 1, further containing glycol ethers. The ink according to claim 2, wherein the glycol ethers are alkylene glycol monoalkyl ethers. A recording medium to which the ink according to any one of claims 1 to 3 is attached. An inkjet recording method for recording by ejecting a droplet of ink according to any one of claims 1 to 3 from an inkjet printer and adhering it to a recording medium.