Manufacturing method of printed matter

Abstract

To provide a method for producing the printed matter in which a fabric is printed with ink, in a convenient manner and with excellent dischargeability.SOLUTION: A method for producing the printed matter in which a fabric is printed with ink, includes a passing step for passing ink through a hollow fiber sheet at around the normal pressure, and a printing step for printing on the fabric with the ink by an inkjet printing method after the passing step.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a printed matter using an inkjet printing method. [Background technology]

[0002] Conventionally, pigment printing has been used as a method for printing images such as letters, pictures, and patterns on fabrics such as woven fabrics, nonwoven fabrics, and knitted fabrics. The pigment printing method is a method in which a printing ink containing a color pigment and a binder resin is applied to a fabric, and a drying and curing process is performed as necessary to fix the printing ink to the fabric. Conventionally, screen printing, roller printing, and the like have been used as pigment printing methods for fabrics, but from the viewpoint of excellent productivity for small-lot production of a wide variety of products and instant printing properties, an inkjet printing method in which printing ink is ejected from a nozzle and applied to the fabric has been considered.

[0003] In recent years, the inkjet printing method has progressed in speed and resolution, and there is a demand for ejecting finer ink droplets at high frequency and stably for a long period of time. However, when ink is ejected at high frequency, pressure and pressure are repeatedly applied and depressurized at high speed many times during ink ejection, which makes it easy for bubbles to occur, and this causes problems such as ink ejection failure and landing position deviation during ink ejection, resulting in deterioration of ejection characteristics. To solve this problem, ink used in inkjet printing is degassed to reduce the amount of dissolved gas in the ink as much as possible and suppress the generation of bubbles during ejection (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-017712 [Patent Document 2] Japanese Patent Application Publication No. 11-209670 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the methods disclosed in Patent Documents 1 and 2 are mainly studied for inks containing dissolved liquids such as dyes. Here, the fabric is a permeable substrate, and in order to maintain a predetermined print density and water resistance (solvent resistance) of the printed part, the ink for textile printing must contain a high concentration of pigment and binder resin in the ink to a level that can maintain the water resistance of the fabric while still allowing inkjet printing. For this reason, in the inkjet printing method for textile printing, not only can the storage stability of the ink for textile printing be reduced, but there is also a risk that the resin or the like may clog the minute nozzle holes of the head, impairing the ejection characteristics. Therefore, there is still room for improvement in the ejection characteristics of textile printing inks that contain pigments, which are coloring agents that are poorly soluble or insoluble in water, and binder resins.

[0006] An object of the present invention is to provide a method for producing a printed matter having excellent ejection characteristics by a simple method, in which ink is printed on a fabric. [Means for solving the problem]

[0007] The present invention encompasses the following aspects. (1) A method for producing a printed matter in which ink is printed on a fabric, comprising the steps of: a step of passing ink through a hollow fiber sheet under approximately normal pressure; a printing step of printing the ink after the liquid passing step on a fabric by an inkjet printing method; A method for producing a printed matter, comprising:

[0008] (2) The method for producing a printed matter according to (1) above, wherein in the ink passing step, the ink is passed through the hollow fiber sheet under a pressure of 70 to 110 kPa.

[0009] (3) The method for producing a printed matter according to (1) or (2) above, wherein in the passing step, the ink is passed through the hollow fiber sheet at a passing speed of 0.1 to 500 mL / min.

[0010] (4) The ink contains at least one binder resin, The method for producing a printed matter according to any one of (1) to (3) above, wherein the content of the binder resin is 1 to 50% by mass of the total ink mass.

[0011] (5) The method for producing a printed matter according to any one of (1) to (4) above, wherein the ink has a viscosity of 20 mPa·s or less and a surface tension of 20 mN / m to 40 mN / m.

[0012] (6) The hollow fiber sheet includes a plurality of hollow fibers, The method for producing a printed matter according to any one of (1) to (5) above, wherein the hollow fiber has an outer diameter of 0.01 to 1.0 mm. Effect of the Invention

[0013] According to the present invention, it is possible to provide a method for producing a printed item having excellent ejection characteristics by a simple method, in which ink is printed on a fabric. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a schematic diagram of a microreactor used in this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention will be described in detail below. The following description of the components may be based on representative embodiments or specific examples of the present invention, but the present invention is not limited to such embodiments or specific examples. In the following description, "(meth)acrylic acid" means methacrylic acid or acrylic acid, "(meth)acrylate" means methacrylate or acrylate, and "(meth)acryloyl" means methacryloyl or acryloyl. Furthermore, a numerical range expressed using "~" means a range that includes the numerical values ​​before and after "~" as the lower and upper limits.

[0016] The manufacturing method of the present invention is a method for manufacturing a printed matter in which ink is printed on a fabric, and is characterized by including a liquid passing step of passing ink through a hollow fiber sheet under near normal pressure, and a printing step of printing the ink after the liquid passing step onto the fabric by an inkjet printing method.

[0017] The purpose of the deaeration hollow fiber module is to deaeration the ink under reduced pressure to reduce the amount of dissolved gas contained in the ink. It has been common knowledge in the industry that the amount of dissolved gas in the ink cannot be reduced even if a deaeration hollow fiber module is used under near normal pressure, and that improvement in the ejection characteristics cannot be expected. Therefore, no consideration has been given to passing ink through a deaeration hollow fiber module under near normal pressure, which is different from the original purpose of using a deaeration hollow fiber module to deaeration the ink.

[0018] However, the present inventors unexpectedly found that when an ink, which is an aqueous pigment composition suitable for printing on fabrics, was passed through a hollow fiber sheet, which was a component of a hollow fiber module for deaeration, under near normal pressure, regardless of whether deaeration was performed or not, the ejection characteristics of the ink were improved, which led to the completion of the present invention.

[0019] The action, mechanism, etc., of the liquid passing step of the present invention have not been fully clarified at the present stage. However, it is presumed that this unexpected effect of improving the ejection characteristics is due to the fact that even if pseudo-aggregates are generated in the ink due to changes over time in the textile printing ink, the pseudo-aggregates are loosened during the liquid passing process through the multiple hollow fibers at near normal pressure, thereby suppressing the deterioration of the ejection characteristics caused by the pseudo-aggregates, etc.

[0020] The production method of the present invention does not require the conventional degassing treatment under reduced pressure, but is a method capable of improving the ejection characteristics of a textile printing ink by a simple treatment at approximately normal pressure. Furthermore, the manufacturing method of the present invention is also excellent from the viewpoint of economy. In the conventional method of using a deaeration hollow fiber module, a high degree of vacuum is required, so when the deaeration hollow fiber module is incorporated into an inkjet device, a large-sized decompression device must be installed to handle the high degree of vacuum for each ink series of each color, and a huge amount of space is required in the inkjet device. This causes problems such as an increase in size of the inkjet device and an increase in the cost of the device. In contrast, the manufacturing method of the present invention is carried out under near normal pressure, so that a large-sized decompression device is not required for the inkjet device, and the inkjet device can be made smaller and the cost of the device can be reduced, resulting in excellent economy.

[0021] The production method of the present invention will now be described in detail.

[0022] (Manufacturing method of printed matter) The manufacturing method of the present invention is a method for manufacturing a printed matter in which ink is printed on a fabric, and is characterized by including a liquid passing step of passing ink through a hollow fiber sheet under approximately normal pressure, and a printing step of printing the ink after the liquid passing step onto the fabric by an inkjet printing method.

[0023] The fabric is not particularly limited, and examples thereof include various fiber materials such as cotton, silk, wool, hemp, nylon, polyester, polyurethane, rayon, and acrylic fibers, and may also be blends, interwoven fabrics, and nonwoven fabrics of these.

[0024] <Liquid passing process> The liquid passing step is a step of passing the ink through the hollow fiber sheet under near normal pressure. In this specification, when normal pressure is 100 kPa, near normal pressure means a pressure in the range of 70 to 110 kPa. Among them, 90 to 110 kPa is preferable from the viewpoint of facilitating pressure adjustment and simplifying the device configuration.

[0025] The method of passing the ink through the hollow fiber sheet is not particularly limited as long as the ink is passed under the above-mentioned normal pressure, and any conventionally known method can be used. Examples of the method of passing the ink through the hollow fiber sheet include a natural drop method in which the ink falls by gravity, an extrusion method in which pressure is applied from the ink inlet side of the hollow fiber sheet by a piston or the like, and a suction method in which suction is performed from the ink outlet side.

[0026] When the liquid passing treatment is carried out under normal pressure, for example, the above-mentioned gravity drop method can be used. When the liquid passing treatment is carried out under a pressure close to or equal to normal pressure, in other words, under a slightly increased pressure, the above-mentioned extrusion method, for example, can be used. Furthermore, when the liquid passing process is carried out under a pressure close to or less than normal pressure, in other words, under a slightly reduced pressure, for example, the above-mentioned suction method or the like can be used.

[0027] The ink passing speed when passing through the hollow fiber sheet cannot be generally defined because it differs depending on the viscosity of the ink, but is usually 0.1 to 500 mL / min.

[0028] <Ink>

[0029] The ink of the present embodiment is not particularly limited, and any known and commonly used ink for textile printing can be used, but for example, an ink containing a solvent such as an aqueous medium (C) and a coloring material (B) can be used. In particular, it is preferable to use an ink further containing a binder resin (A) in order to obtain a printed matter having excellent wash resistance and abrasion resistance.

[0030] It is preferable to use an ink in which the binder resin (A), coloring material (B), etc. are present in a dissolved or dispersed state in an aqueous medium (C) that is a solvent.

[0031] <<Binder resin (A)>> The binder resin (A) is for fixing the pigment onto the recording medium. In particular, when printing on fabric, if an ink with a high content of the binder resin (A) is used, the wash resistance and abrasion resistance (wet and dry) of the printed matter are improved, but the texture of the fabric tends to become slightly harder. Therefore, the content of the binder resin (A) is preferably 50% by mass or less, more preferably 30% by mass or less, preferably 1% by mass or more, and more preferably 5% by mass or more, based on the total ink mass, in order to obtain a printed matter excellent in wash resistance and abrasion resistance.

[0032] As described above, the binder resin (A) is for fixing the color material (B) such as a pigment onto the fabric. If a binder resin with a glass transition temperature higher than room temperature is used, the texture of the fabric tends to become slightly hard. Therefore, it is preferable to use a binder resin (A) with a glass transition temperature of 0°C or lower in order to maintain a good texture and washability even when the ink or printed matter is used in a low-temperature region.

[0033] The ratio of the binder resin (A) to the colorant (B) may be within the range generally used for inks. For example, the ratio of the binder resin (A) to the colorant is preferably in the range of 1:3 to 8:1, and more preferably in the range of 1:2 to 3.5:1 in order to obtain printed matter with even better abrasion resistance. As the binder resin (A), from the viewpoint of obtaining a printed matter having even better abrasion resistance, it is preferable to use a binder resin having a weight average molecular weight of 10,000 or more, and it is more preferable to use a binder resin having a weight average molecular weight of 30,000 or more. Furthermore, as the binder resin (A), from the viewpoint of imparting even better dischargeability, it is preferable to use a binder resin having a weight average molecular weight of 200,000 or less.

[0034] Examples of the binder resin (A) include urethane resins, polyvinyl alcohols, polyvinylpyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymers, potassium acrylate-acrylonitrile copolymers, vinyl acetate-acrylic acid ester copolymers, and acrylic acid-acrylic acid alkyl ester copolymers; styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid alkyl ester copolymers, styrene-α-methylstyrene-acrylic acid copolymers, and styrene-acrylic acid resins such as styrene-maleic acid; styrene-maleic anhydride; vinyl naphthalene-acrylic acid copolymers; vinyl naphthalene-maleic acid copolymers; vinyl acetate-ethylene copolymers, vinyl acetate-fatty acid vinyl ethylene copolymers, vinyl acetate-maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, and vinyl acetate-acrylic acid copolymers and their salts.

[0035] Among these, it is preferable to use a urethane resin or an acrylic resin as the binder resin, since these are easily available and improve the abrasion resistance of the printed matter, and in particular, this is preferable for further improving the washing resistance (washing fastness) and abrasion resistance (dry abrasion fastness and wet abrasion fastness) of the printed matter on the fabric.

[0036] The urethane resin used is a urethane resin obtained by reacting one or more polyols selected from the group consisting of polyether polyols, polyester polyols, and polycarbonate polyols, a polyol having a hydrophilic group which is an anionic group, a cationic group, a polyoxyethylene group, or a polyoxyethylene-polyoxypropylene group, with a polyisocyanate.

[0037] The weight average molecular weight of the urethane resin is preferably 5,000 to 200,000, and more preferably 20,000 to 150,000, in order to further improve the abrasion resistance of the printed matter.

[0038] Examples of polyether polyols include compounds having two or more active hydrogen groups, such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, neopentyl glycol, glycerin, trimethylolethane, trimethylolpropane, sorbitol, sucrose, aconite sugar, femimellitic acid, phosphoric acid, ethylenediamine, diethylenetriamine, triisopropanolamine, pyrogallol, dihydroxybenzoic acid, hydroxyphthalic acid, and 1,2,3-propanetrithiol, which are subjected to addition polymerization of cyclic ether compounds such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclophenylene, or ring-opening polymerization of cyclic ether compounds using a cationic catalyst, a protonic acid, a Lewis acid, or the like as a catalyst.

[0039] The polyester polyol can be obtained by a dehydration condensation reaction of a diol compound, a dicarboxylic acid, a hydroxycarboxylic acid compound, etc., a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, and copolymerization of the polyester obtained by these reactions. Examples of the diol compound that is the raw material of this polyester polyol include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, hydroquinone, and alkylene oxide adducts thereof.

[0040] Examples of dicarboxylic acids that can be used as raw materials for polyester polyols include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyldicarboxylic acid, and 1,2-bis(phenoxy)ethane-p,p'-dicarboxylic acid.

[0041] Examples of hydroxycarboxylic acids that can be used as raw materials for polyester polyols include p-hydroxybenzoic acid and p-(2-hydroxyethoxy)benzoic acid.

[0042] As the polycarbonate polyol, for example, one obtained by reacting a carbonate ester with a low molecular weight polyol, preferably a linear aliphatic diol, can be used.

[0043] As the carbonate ester, for example, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate, etc. can be used.

[0044] Examples of low molecular weight polyols that can react with carbonate esters include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, and 1,10-decanediol. Examples of the polyol that can be used include relatively low molecular weight dihydroxy compounds such as bisphenol A, bisphenol F, and 4,4'-biphenol, polyether polyols such as polyethylene glycol, polypropylene glycol, and polyoxytetramethylene glycol, and polyester polyols such as polyhexamethylene adipate, polyhexamethylene succinate, and polycaprolactone.

[0045] The polyol having a polycarbonate structure is preferably used in the range of 10% by mass to 90% by mass based on the total mass of the polyol and polyisocyanate used in the production of the polycarbonate-based urethane resin.

[0046] Furthermore, the urethane resin has a hydrophilic group, which provides dispersion stability in the ink.

[0047] As the hydrophilic group, what is generally called an anionic group, a cationic group, or a nonionic group can be used, with the use of an anionic group or a cationic group being particularly preferred.

[0048] Examples of the anionic group that can be used include a carboxyl group, a carboxylate group, a sulfonic acid group, and a sulfonate group. Among these, it is preferable to use a carboxylate group or a sulfonate group that has been partially or completely neutralized with a basic compound or the like in order to maintain good water dispersibility.

[0049] Examples of basic compounds that can be used to neutralize the anionic groups, such as carboxyl groups and sulfonic acid groups, include organic amines such as ammonia, triethylamine, pyridine, and morpholine, alkanolamines such as monoethanolamine, and metal base compounds containing Na, K, Li, Ca, and the like. Among these, it is preferable to select an organic amine with a boiling point of 100° C. or less from the viewpoint of reducing residue in the dried coating.

[0050] In addition, as the cationic group, for example, a tertiary amino group can be used. As the acid that can be used when neutralizing a part or all of the tertiary amino groups, for example, formic acid, acetic acid, etc. can be used. In addition, as the quaternizing agent that can be used when quaternizing a part or all of the tertiary amino groups, for example, dialkyl sulfates such as dimethyl sulfate, diethyl sulfate, etc. can be used.

[0051] As the nonionic group, for example, a polyoxyalkylene group such as a polyoxyethylene group, a polyoxypropylene group, a polyoxybutylene group, a poly(oxyethylene-oxypropylene) group, and a polyoxyethylene-polyoxypropylene group can be used. Among them, it is preferable to use a polyoxyalkylene group having an oxyethylene unit in order to further improve hydrophilicity.

[0052] The hydrophilic group imparts better water dispersibility when it is present in an amount of 0.5% by mass to 30% by mass based on the entire urethane resin, and a range of 1% by mass to 20% by mass is more preferable.

[0053] In addition, the ink according to this embodiment can use a crosslinking agent, which will be described later, for the purpose of further improving the abrasion resistance. When a crosslinking agent is used, it is preferable to use a urethane resin having a functional group capable of undergoing a crosslinking reaction with the functional group of the crosslinking agent.

[0054] Examples of functional groups capable of undergoing a crosslinking reaction with a crosslinking agent include carboxyl groups and carboxylate groups that can be used as hydrophilic groups. Carboxyl groups and the like contribute to the aqueous dispersion stability of the urethane resin in an aqueous medium, and when they undergo a crosslinking reaction, they also act as functional groups and can undergo a partial crosslinking reaction with the crosslinking agent.

[0055] When a carboxyl group or the like is used as a functional group capable of undergoing a crosslinking reaction with a crosslinking agent, the urethane resin preferably has an acid value of 5 to 50, and in terms of improving fastness, it is preferable to use one having an acid value of 10 to 40. Note that the acid value in this embodiment is a theoretical value calculated based on the amount of an acid group-containing compound, such as a carboxyl group-containing polyol, used in the production of the urethane resin.

[0056] The urethane resin can be produced, for example, by reacting a polyol with a polyisocyanate and, if necessary, with a chain extender.

[0057] As the chain extender, polyamines and other compounds containing active hydrogen atoms can be used.

[0058] Examples of polyamines include diamines such as ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, and 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, and N-methylaminopropylamine; and diethylene Triamine, dipropylenetriamine, triethylenetetramine; hydrazine, N,N'-dimethylhydrazine, 1,6-hexamethylenebishydrazine; succinic acid dihydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide; β-semicarbazidopropionic acid hydrazide, 3-semicarbazido-propyl-carbazic acid ester, semicarbazido-3-semicarbazidomethyl-3,5,5-trimethylcyclohexane can be used, and among them, ethylenediamine is preferably used.

[0059] Other active hydrogen-containing compounds that can be used include, for example, glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, neopentyl glycol, sucrose, methylene glycol, glycerin, and sorbitol; phenols such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, and hydroquinone; and water.

[0060] The chain extender is preferably used in such a range that the equivalent of the amino group and active hydrogen atom-containing group of the chain extender is 1.9 or less (equivalent ratio) relative to the equivalent of the isocyanate group of the urethane prepolymer obtained by reacting a polyol with a polyisocyanate, more preferably in the range of 0.0 to 1.0 (equivalent ratio), and more preferably 0.5 mass%.

[0061] The chain extender can be used during or after the reaction of the polyol with the polyisocyanate. Also, the chain extender can be used when dispersing the urethane resin obtained above in an aqueous medium to make it aqueous.

[0062] Examples of polyols other than those mentioned above include relatively low molecular weight polyols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, hydroquinone and alkylene oxide adducts thereof, glycerin, trimethylolethane, trimethylolpropane, sorbitol, and pentaerythritol. These polyols can be used alone or in combination of two or more.

[0063] Examples of polyisocyanates that react with polyols to form urethane resins include aromatic diisocyanates such as phenylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and naphthalene diisocyanate, and aliphatic or alicyclic structure-containing diisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate. These can be used alone or in combination of two or more.

[0064] The acrylic resin usable for the binder resin (A) is not particularly limited, and examples thereof include a homopolymer or copolymer of a (meth)acrylate, and a copolymer of a (meth)acrylate and a vinyl monomer copolymerizable with the (meth)acrylate.

[0065] Examples of (meth)acrylates and vinyl monomers copolymerizable with (meth)acrylates include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, isopropyl (meth)acrylate, and isobutyl (meth)acrylate; aromatic (meth)acrylates such as benzyl (meth)acrylate; and hydroxyl group-containing (meth)acrylates such as 2-hydroxyethyl (meth)acrylate and 2-hydroxypropyl (meth)acrylate. Monomers; alkyl polyalkylene glycol mono(meth)acrylates such as methoxy polyethylene glycol mono(meth)acrylate and methoxy polypropylene glycol mono(meth)acrylate; fluorine-based (meth)acrylates such as perfluoroalkylethyl (meth)acrylate; styrene, styrene derivatives (p-dimethylsilylstyrene, (p-vinylphenyl)methylsulfide, p-hexynylstyrene, p-methoxystyrene, p-tert-butyldimethylsiloxystyrene, o-methylstyrene, p-methylstyrene, p-tert-butyldimethylsiloxystyrene, t-butylstyrene, α-methylstyrene, etc.), aromatic vinyl compounds such as vinyl naphthalene, vinyl anthracene, 1,1-diphenylethylene; glycidyl (meth)acrylate, epoxy (meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylene glycol tetra(meth)acrylate, 2-hydroxy-1,3-diacryloxypropane, 2,2-bis[4-(acryloxymethoxy)phenyl]propane, 2,2-bi (Meth)acrylate compounds such as tris[4-(acryloxyethoxy)phenyl]propane, dicyclopentenyl (meth)acrylate, tricyclodecanyl (meth)acrylate, tris(acryloxyethyl)isocyanurate, and urethane (meth)acrylate; (meth)acrylates having an alkylamino group such as dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, and dimethylaminopropyl (meth)acrylate; vinylpyridine compounds such as 2-vinylpyridine, 4-vinylpyridine, and naphthylvinylpyridine;Conjugated dienes such as 1,3-butadiene, 2-methyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, and 1,3-cyclohexadiene can be used. These monomers can be used alone or in combination of two or more.

[0066] The acrylic resin used in this embodiment is preferably one obtained by copolymerizing the above-mentioned monomers with a monomer having a specific functional group, in order to improve the texture of the printed matter, etc. Examples of the monomer having such a functional group include a monomer having a carboxyl group, a monomer having an epoxy group, a monomer having a hydrolyzable silyl group, and a monomer having an amide group.

[0067] Examples of monomers having a carboxyl group that can be used include (meth)acrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic anhydride, and citraconic acid.

[0068] Examples of monomers having a hydrolyzable silyl group include vinyl silane compounds such as vinyl methyl dimethoxy silane, vinyl trimethoxy silane, vinyl triethoxy silane, and vinyl tris (2-methoxy ethoxy) silane; and (meth) acryloyloxy alkyl silane compounds such as 3- (meth) acryloyloxy propyl trimethoxy silane, 3- (meth) acryloyloxy propyl methyl dimethoxy silane, 3- (meth) acryloyloxy propyl triethoxy silane, and 3- (meth) acryloyloxy propyl methyl diethoxy silane. These monomers can be used alone or in combination of two or more.

[0069] As the monomer having an amide group, an acrylamide compound such as (meth)acrylamide, N,N-dimethylacrylamide, isopropylacrylamide, or diacetoneacrylamide can be used.

[0070] The dispersion form of the acrylic resin in water is not particularly limited, and examples thereof include emulsions forcibly emulsified with an emulsifier, and dispersions having nonionic groups or neutralized ionic groups in the resin. In particular, the above-mentioned acrylic resin is preferably a dispersion obtained by neutralizing an acrylic resin having a carboxyl group with a basic compound. The basic compound can be the same as the basic compound exemplified as one that can be used to neutralize the carboxyl group of the urethane resin.

[0071] <<Color material (B)>> As the coloring material (B) that can be used in the ink of this embodiment, a known and commonly used pigment, dye, etc. can be used. Among them, it is preferable to use a pigment in order to produce a printed matter with excellent weather resistance, etc. Also, as the coloring material (B), a coloring agent in which a pigment is coated with a resin can be used.

[0072] The pigment is not particularly limited, and organic or inorganic pigments that are commonly used in conventional screen printing or aqueous ink jet printing inks can be used.

[0073] The pigment may be either a non-acid-treated pigment or an acid-treated pigment, and may be in either a dry powder or wet cake form.

[0074] As the inorganic pigment, for example, iron oxide and carbon black produced by a contact method, a furnace method, a thermal method, or the like can be used.

[0075] Examples of organic pigments that can be used include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.), polycyclic pigments (such as phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, thioindigo pigments, isoindolinone pigments, quinophthalone pigments, etc.), lake pigments (such as basic dye-type chelates, acid dye-type chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like.

[0076] Specific examples of pigments are shown below. However, the pigments are not limited to these examples. These pigments can be used alone or in combination of two or more kinds.

[0077] Specific examples of pigments used in black inks include Mitsubishi Chemical's No. 2300, No. 2200B, No. 900, No. 980, No. 960, No. 33, No. 40, No. 45, No. 45L, No. 52, HCF88, MCF88, MA7, MA8, MA100, etc.; Columbia's Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc.; Cabot's Regal 400R, Regal 330R, Regal 660R, Mogul L, Mogul 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc.; and Degussa's Color Black. Examples of carbon black include FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Printex 35, U, V, 1400U, Special Black 6, 5, 4, 4A, NIPEX150, NIPEX160, NIPEX170, and NIPEX180.

[0078] Specific examples of pigments used in yellow inks include CI Pigment Yellow 1, 2, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 120, 128, 129, 138, 150, 151, 154, 155, 174, 180, and 185.

[0079] Specific examples of pigments used in the magenta ink include CI Pigment Violet 19, CI Pigment Red 5, 7, 12, 48(Ca), 48(Mn), 57(Ca), 57:1, 112, 122, 123, 146, 168, 176, 184, 185, 202, 209, and mixtures or solid solutions of at least two or more pigments selected from these pigments.

[0080] Specific examples of pigments used in cyan inks include CI Pigment Blue 1, 2, 3, 15, 15:3, 15:4, 15:6, 16, 22, 60, 63, 66, and the like.

[0081] Specific examples of pigments used in the red ink include CI Pigment Red 17, 49:2, 112, 149, 150, 177, 178, 179, 188, 254, 255, and 264.

[0082] Specific examples of pigments used in orange inks include CI Pigment Orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43, 63, 64, 71, 73, and 81.

[0083] Specific examples of pigments used in green inks include CI Pigment Green 7, 10, 36, 58, 59, and the like.

[0084] Specific examples of pigments used in the violet ink include CI Pigment Violet 19, 23, 32, 33, 36, 38, 43, 50, and the like.

[0085] Specific examples of pigments that can be used in the white ink include alkaline earth metal sulfates, carbonates, finely powdered silicic acid, synthetic silicates, and other silicates, calcium silicate, alumina, alumina hydrate, titanium oxide, zinc oxide, talc, clay, etc. These may be surface-treated.

[0086] In order to ensure that the pigment is present stably in the ink, it is preferable that a means be taken to disperse the pigment well in the aqueous medium (C).

[0087] The above means include, for example: (i) A method in which a pigment is dispersed in an aqueous medium (C) together with a pigment dispersant by a dispersion method described below. (ii) A method of dispersing and / or dissolving a self-dispersing pigment having a dispersibility-imparting group (hydrophilic functional group and / or its salt) bonded directly to the surface of the pigment or indirectly bonded via an alkyl group, an alkyl ether group, an aryl group, or the like, in an aqueous medium (C) is exemplified.

[0088] The self-dispersing pigment may be, for example, a pigment that has been subjected to a physical or chemical treatment to bond (graft) a dispersibility-imparting group or an active species having a dispersibility-imparting group to the surface of the pigment. The self-dispersing pigment may be produced, for example, by vacuum plasma treatment, oxidation treatment with hypohalous acid and / or a hypohalous acid salt, oxidation treatment with ozone, or the like, a wet oxidation method in which the pigment surface is oxidized with an oxidizing agent in water, or a method in which a carboxyl group is bonded via a phenyl group by bonding p-aminobenzoic acid to the pigment surface.

[0089] Since the aqueous ink containing the self-dispersing pigment does not need to contain a pigment dispersant, it is easy to prepare an ink with excellent ejection stability without foaming caused by the pigment dispersant. In addition, the aqueous ink containing the self-dispersing pigment is easy to handle and can contain a larger amount of pigment because a significant increase in viscosity caused by the pigment dispersant is suppressed, and it can be used to produce printed matter with high print density.

[0090] Commercially available self-dispersing pigments can also be used. Examples of such commercially available products include Microjet CW-1 (product name; manufactured by Orient Chemical Industries, Ltd.), CAB-O-JET200, and CAB-O-JET300 (all product names; manufactured by Cabot Corporation).

[0091] In this embodiment, if the composition of the ink is excessively changed in order to prevent deterioration of image quality such as streaks, the print density and washability of the printed matter may tend to decrease. In order to prevent the occurrence of streaks, maintain excellent dispersion stability of the colorant (B), and improve the print density and washability of the printed matter, the colorant (B) is preferably used in the range of 1% by mass to 20% by mass, more preferably 2% by mass to 10% by mass, based on the total amount of the ink.

[0092] <<Pigment dispersant>> The pigment dispersant can be suitably used when a pigment is used as the colorant (B).

[0093] Examples of pigment dispersants that can be used include polyvinyl alcohols, polyvinylpyrrolidones, acrylic resins such as acrylic acid-acrylic acid ester copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid ester copolymers, styrene-α-methylstyrene-acrylic acid copolymers, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymers, styrene-maleic acid copolymers, styrene-maleic anhydride copolymers, and vinylnaphthalene-acrylic acid copolymers, as well as aqueous resins and salts of aqueous resins. Examples of pigment dispersants that can be used include Ajisper PB series from Ajinomoto Fine-Techno Co., Ltd., Disperbyk series from BYK Japan Co., Ltd., EFKA series from BASF, SOLSPERSE series from Lubrizol Japan Co., Ltd., and TEGO series from Evonik.

[0094] As a pigment dispersant, it is preferable to use the polymer (G) described below, which can significantly reduce coarse particles and, as a result, impart the good ejection stability required when the ink is ejected by an inkjet method.

[0095] As the polymer (G), a polymer having an anionic group can be used. In particular, it is preferable to use a polymer having a number average molecular weight in the range of 1000 to 6000, which has a solubility in water of 0.1 g / 100 mL or less and is capable of forming fine particles in water when the neutralization rate of the anionic group with a basic compound is 100%.

[0096] The solubility of polymer (G) in water can be defined as follows. That is, 0.5 g of polymer (E) whose particle size has been adjusted to the range of 250 μm to 90 μm using sieves with 250 μm and 90 μm openings is sealed in a bag made of 400 mesh wire netting, immersed in 50 mL of water, and left to stand for 24 hours with gentle stirring at a temperature of 25°C. After immersion for 24 hours, the 400 mesh wire netting containing polymer (E) is dried for 2 hours in a dryer set at 110°C. The change in weight of the 400 mesh wire netting containing polymer (E) before and after immersion in water is measured, and the solubility is calculated by the following formula.

[0097]

number

[0098] In this embodiment, whether or not fine particles are formed in water when the neutralization rate of the anionic group with the basic compound is set to 100% can be determined as follows. (1) The acid value of polymer (G) is measured in advance by an acid value measurement method based on JIS test method K 0070-1992. Specifically, 0.5 g of polymer (G) is dissolved in tetrahydrofuran, and the acid value is determined by titration with 0.1 M potassium hydroxide alcohol solution using phenolphthalein as an indicator. (2) 1 g of polymer (G) is added to 50 mL of water, and then a 0.1 mol / L aqueous potassium hydroxide solution sufficient to neutralize the resulting acid value 100% is added to neutralize the acid value 100%. (3) The 100% neutralized liquid is exposed to ultrasonic waves in an ultrasonic cleaner (SND Corporation ultrasonic cleaner US-102, 38 kHz self-oscillation) at a temperature of 25°C for 2 hours, and then left to stand at room temperature for 24 hours.

[0099] After leaving it for 24 hours, the liquid at a depth of 2 centimeters from the liquid surface is sampled and the presence of fine particles is confirmed by determining whether light scattering information due to fine particle formation can be obtained using a dynamic light scattering particle size distribution analyzer (Nikkiso Co., Ltd., dynamic light scattering particle size analyzer "Microtrac Particle Size Distribution Analyzer UPA-ST150").

[0100] In order to further improve the stability of the fine particles formed by the polymer (G) in water, the particle diameter of the fine particles is preferably in the range of 5 nm to 1000 nm, more preferably in the range of 7 nm to 700 nm, and most preferably in the range of 10 nm to 500 nm. In addition, the narrower the particle size distribution of the fine particles, the better the dispersion stability tends to be, but even if the particle size distribution is broad, it is possible to obtain an ink with better dispersion stability than before. Note that the particle diameter and particle size distribution can be measured using, for example, a dynamic light scattering particle size distribution measuring device (dynamic light scattering particle size measuring device "Microtrack particle size distribution meter UPA-ST150" manufactured by Nikkiso Co., Ltd.) in the same manner as the method for measuring the fine particles.

[0101] The neutralization rate of the polymer (G) can be determined by the following formula:

[0102]

number

[0103] The acid value of the polymer (G) can be measured based on JIS test method K 0070-1992. Specifically, the acid value can be determined by dissolving 0.5 g of a sample in tetrahydrofuran and titrating the sample with a 0.1 M alcoholic solution of potassium hydroxide using phenolphthalein as an indicator.

[0104] The number average molecular weight of the polymer (G) is preferably in the range of 1000 to 6000, more preferably 1300 to 5000, and more preferably 1500 to 4500, which can effectively suppress aggregation of the color material (B) such as a pigment in the aqueous medium (C) and is more preferable for obtaining an ink having good dispersion stability of the color material (B).

[0105] The number average molecular weight is a value calculated as polystyrene by GPC (gel permeation chromatography), specifically, a value measured under the following conditions.

[0106] (Method of measuring number average molecular weight (Mn)) Measured by gel permeation chromatography (GPC) under the following conditions. Measurement equipment: High-speed GPC equipment (Tosoh Corporation "HLC-8220GPC") Column: The following columns manufactured by Tosoh Corporation are connected in series and used.

[0107] "TSKgel G5000" (7.8mm I.D. x 30cm) x 1 "TSKgel G4000" (7.8mm I.D. x 30cm) x 1 "TSKgel G3000" (7.8mm I.D. x 30cm) x 1 "TSKgel G2000" (7.8mmI.D. x 30cm) x 1 Detector: RI (differential refractometer) Column temperature: 40℃ Eluent: Tetrahydrofuran Flow rate: 1.0mL / min Injection volume: 100 μL (sample concentration 0.4% by mass in tetrahydrofuran solution) Standard sample: Prepare a calibration curve using the following standard polystyrene. (Standard polystyrene) "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0108] The surface tension of the ink containing the polymer (G) is preferably 30 dyn / cm or more, more preferably 40 dyn / cm or more, and particularly preferably 65 dyn / cm to 75 dyn / cm, which is close to the surface tension of water. The surface tension value is measured by adding 1 g of the polymer (G) to water, adding a 0.1 mol / L potassium hydroxide aqueous solution sufficient to neutralize the resulting acid value by 100%, and measuring the surface tension of the polymer solution.

[0109] As the polymer (G), a polymer that is insoluble or poorly soluble in water when unneutralized and forms fine particles when 100% neutralized can be used, and is not particularly limited as long as it is a polymer that has a hydrophobic group in one molecule in addition to an anionic group, which is a hydrophilic group.

[0110] Such a polymer may be a block polymer having a polymer block having a hydrophobic group and a polymer block having an anionic group. In the polymer (G), the number of anionic groups and the solubility in water are not necessarily determined by the acid value or the number of anionic groups at the time of polymer design. For example, even if the polymer has the same acid value, the polymer with a low molecular weight tends to have a high solubility in water, and the polymer with a high molecular weight tends to have a low solubility in water. For this reason, in this embodiment, the polymer (G) is determined by its solubility in water.

[0111] The polymer (G) may be a homopolymer, but is preferably a copolymer, and may be a random polymer, a block polymer, or an alternating polymer, but is preferably a block polymer. The polymer may be a branched polymer, but is preferably a linear polymer.

[0112] In addition, the polymer (G) is preferably a vinyl polymer from the viewpoint of freedom in design. In the present embodiment, a method for producing a vinyl polymer having the desired molecular weight and solubility characteristics is preferably by using "living polymerization" such as living radical polymerization, living cationic polymerization, or living anionic polymerization.

[0113] Among these, the polymer (G) is preferably a vinyl polymer produced using a (meth)acrylate monomer as one of the raw materials, and as a method for producing such a vinyl polymer, living radical polymerization and living anionic polymerization are preferred, and living anionic polymerization is further preferred from the viewpoint of enabling more precise design of the molecular weight of the block polymer and each segment.

[0114] The polymer (G) produced by living anionic polymerization is specifically a polymer represented by general formula (1).

[0115] [ka]

[0116] In general formula (1), A 1 represents an organolithium initiator residue, A 2 represents a polymer block having a hydrophobic group, and A 3 represents a polymer block containing an anionic group, n represents an integer of 1 to 5, and B represents an aromatic group or an alkyl group.

[0117] In general formula (1), A 1 represents an organolithium initiator residue. Specific examples of the organolithium initiator include alkyl lithiums such as methyl lithium, ethyl lithium, propyl lithium, butyl lithium (n-butyl lithium, sec-butyl lithium, iso-butyl lithium, tert-butyl lithium, etc.), pentyl lithium, hexyl lithium, methoxymethyl lithium, and ethoxymethyl lithium; phenyl alkylene lithiums such as benzyl lithium, α-methylstyryl lithium, 1,1-diphenyl-3-methylpentyl lithium, 1,1-diphenylhexyl lithium, and phenylethyl lithium; alkenyl lithiums such as vinyl lithium, allyl lithium, propenyl lithium, and butenyl lithium; alkynyl lithiums such as ethynyl lithium, butynyl lithium, pentynyl lithium, and hexynyl lithium; aryl lithiums such as phenyl lithium and naphthyl lithium; heterocyclic lithiums such as 2-thienyl lithium, 4-pyridyl lithium, and 2-quinolyl lithium; and alkyl lithium magnesium complexes such as tri(n-butyl)magnesium lithium and trimethylmagnesium lithium.

[0118] In the organolithium initiator, the bond between the organic group and lithium is cleaved, and an active end is generated on the organic group side, from which polymerization is initiated. Therefore, an organic group derived from the organolithium is bonded to the end of the resulting polymer. In this embodiment, the organic group derived from the organolithium bonded to the end of the polymer is called an organolithium initiator residue. For example, in the case of a polymer using methyllithium as an initiator, the organolithium initiator acid group is a methyl group, and in the case of a polymer using butyllithium as an initiator, the organolithium initiator acid group is a butyl group.

[0119] In general formula (1), A 2 represents a polymer block having a hydrophobic group. 2 As described above, in addition to the purpose of achieving a suitable balance of solubility, it is preferable that A is a group that is highly adsorbed to the pigment when it comes into contact with the pigment. 2 is preferably a polymer block of a monomer having an aromatic ring or a heterocyclic ring. The polymer block of a monomer having an aromatic ring or a heterocyclic ring is specifically a polymer block of a homopolymer or copolymer obtained by homopolymerizing or copolymerizing a monomer having an aromatic ring, such as a styrene-based monomer, or a monomer having a heterocyclic ring, such as a vinylpyridine-based monomer.

[0120] Examples of monomers having an aromatic ring include styrene-based monomers such as styrene, p-tert-butyldimethylsiloxystyrene, o-methylstyrene, p-methylstyrene, p-tert-butylstyrene, p-tert-butoxystyrene, m-tert-butoxystyrene, p-tert-(1-ethoxymethyl)styrene, m-chlorostyrene, p-chlorostyrene, p-fluorostyrene, α-methylstyrene, and p-methyl-α-methylstyrene, as well as vinylnaphthalene and vinylanthracene.

[0121] Examples of the monomer having a heterocycle include vinylpyridine monomers such as 2-vinylpyridine, 4-vinylpyridine, etc. These monomers can be used alone or in combination of two or more kinds.

[0122] In general formula (1), A 3 represents a polymer block containing an anionic group. 3 As described above, the purpose of the additive is to provide an appropriate solubility, and also to provide dispersion stability in water when a pigment dispersion is formed. Polymer Block A 3 The anionic group in may be, for example, a carboxyl group, a sulfonic acid group, or a phosphoric acid group. Among them, a carboxyl group is preferred because of its preparation, the abundance of monomer varieties, and ease of availability. Two carboxyl groups may be dehydrated and condensed within or between molecules to form an acid anhydride group.

[0123] A 3 The method for introducing the anionic group is not particularly limited, and for example, when the anionic group is a carboxyl group, the polymer block (PB1) may be a homopolymer or copolymer obtained by homopolymerizing or copolymerizing (meth)acrylic acid with other monomers, or the polymer block (PB2) may be a homopolymer or copolymer obtained by homopolymerizing or copolymerizing (meth)acrylate having a protecting group that can be regenerated to an anionic group by deprotection, in which a part or all of the protecting groups that can be regenerated to an anionic group have been regenerated to an anionic group.

[0124] Specific examples of (meth)acrylic acid and (meth)acrylate include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, allyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, n-amyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-lauryl (meth)acrylate, n-tridecyl (meth)acrylate, n-stearyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, and cyclohexyl (meth)acrylate. , 4-tert-butylcyclohexyl (meth)acrylate, isobornyl (meth)acrylate, tricyclodecanyl (meth)acrylate, dicyclopentadienyl (meth)acrylate, adamantyl (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, pentafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, pentadecafluorooctyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, N,Examples of the polyalkylene oxide group-containing (meth)acrylates include N-dimethyl (meth)acrylamide, (meth)acryloylmorpholine, (meth)acrylonitrile, polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, polyethylene glycol-polypropylene glycol (meth)acrylate, polyethylene glycol-polybutylene glycol (meth)acrylate, polypropylene glycol-polybutylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, ethoxypolyethylene glycol (meth)acrylate, butoxypolyethylene glycol (meth)acrylate, octoxypolyethylene glycol (meth)acrylate, lauroxypolyethylene glycol (meth)acrylate, stearoxypolyethylene glycol (meth)acrylate, phenoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, and octoxypolyethylene glycol-polypropylene glycol (meth)acrylate. These monomers can be used alone or in combination of two or more.

[0125] In the living anionic polymerization method, when the monomer used has a group having an active proton such as an anionic group, the active terminal of the living anionic polymerization polymer immediately reacts with the group having an active proton and is deactivated, so that no polymer can be obtained. Since it is difficult to polymerize a monomer having a group having an active proton as it is in the living anionic polymerization, it is preferable to polymerize the monomer in a state in which the group having an active proton is protected, and then to regenerate the group having an active proton by deprotecting the protecting group.

[0126] For this reason, polymer block A 3In the above, it is preferable to use a monomer containing a (meth)acrylate having a protecting group that can be regenerated to an anionic group by deprotection. By using such a monomer, the above-mentioned inhibition of polymerization can be prevented during polymerization. In addition, the anionic group protected by the protecting group can be regenerated to an anionic group by deprotection after obtaining a block polymer.

[0127] For example, when the anionic group is a carboxyl group, the carboxyl group can be regenerated by esterifying the carboxyl group and then deprotecting it by hydrolysis or the like in a subsequent step. In this case, the protecting group convertible to a carboxyl group is preferably a group having an ester bond, and examples thereof include primary alkoxycarbonyl groups such as methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, and n-butoxycarbonyl groups; secondary alkoxycarbonyl groups such as isopropoxycarbonyl and sec-butoxycarbonyl groups; tertiary alkoxycarbonyl groups such as t-butoxycarbonyl groups; phenylalkoxycarbonyl groups such as benzyloxycarbonyl groups; and alkoxyalkylcarbonyl groups such as ethoxyethylcarbonyl groups.

[0128] When the anionic group is a carboxyl group, examples of monomers that can be used include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate (lauryl (meth)acrylate), acrylate), tridecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate (stearyl (meth)acrylate), nonadecyl (meth)acrylate, icosanyl (meth)acrylate, and other alkyl (meth)acrylates; benzyl (meth)acrylate and other phenyl alkylene (meth)acrylates; and ethoxyethyl (meth)acrylate and other alkoxy alkyl (meth)acrylates. These (meth)acrylates can be used alone or in combination of two or more. Among these (meth)acrylates, t-butyl (meth)acrylate and benzyl (meth)acrylate are preferred because they are easily converted into a carboxyl group. In addition, in consideration of industrial availability, t-butyl (meth)acrylate is more preferred.

[0129] In the general formula (1), B represents an aromatic group or an alkyl group having 1 to 10 carbon atoms, and n represents an integer of 1 to 5.

[0130] In the living anionic polymerization method, when a (meth)acrylate monomer is directly polymerized at the active end of a styrene-based polymer having a strong nucleophilicity, the polymerization may not be possible due to nucleophilic attack on the carbonyl carbon. 1 -A 2When polymerizing a (meth)acrylate monomer, a reaction regulator is used to adjust the nucleophilicity, and then the (meth)acrylate monomer is polymerized. B in the general formula (1) is a group derived from the reaction regulator. Specific examples of the reaction regulator include diphenylethylene, α-methylstyrene, and p-methyl-α-methylstyrene.

[0131] By adjusting the reaction conditions, the living anionic polymerization method can be carried out in a batch manner as used in conventional free radical polymerization, and can also be carried out in a continuous polymerization method using a microreactor. In a microreactor, the miscibility of the polymerization initiator and the monomer is good, so the reactions start simultaneously, and the temperature is uniform and the polymerization rate can be made uniform, so the molecular weight distribution of the produced polymer can be narrowed. At the same time, since the growing end is stable, it is easy to produce a block copolymer in which the two components of the block do not mix. In addition, since the reaction temperature is well controllable, it is easy to suppress side reactions.

[0132] A general method for living anionic polymerization using a microreactor will be described with reference to FIG. 1, which is a schematic diagram of a microreactor. A first monomer and a polymerization initiator that starts polymerization are introduced from tube reactors P1 and P2 (7 and 8 in Figure 1), respectively, into a T-shaped micromixer M1 (1 in Figure 1) equipped with a flow path capable of mixing multiple liquids, and the first monomer is subjected to living anionic polymerization in the T-shaped micromixer M1 to form a first polymer (Step 1).

[0133] Next, the obtained first polymer is transferred to a T-shaped micro mixer M2 (2 in FIG. 1), and in the mixer M2, the growing end of the obtained polymer is trapped by a reaction regulator introduced from a tube reactor P3 (9 in FIG. 1) to regulate the reaction (step 2). In this case, the number n in general formula (1) can be controlled by the type and amount of the reaction regulator used.

[0134] Next, the first polymer that has been subjected to reaction control in the T-shaped micromixer M2 is transferred to a T-shaped micromixer M3 (3 in FIG. 1), and in the mixer M3, the second monomer introduced from the tube reactor P4 and the first polymer that has been subjected to reaction control are continuously subjected to living anionic polymerization (step 3).

[0135] The reaction is then quenched with a compound having an active proton, such as methanol, to produce a block copolymer.

[0136] When the polymer (G) represented by the general formula (1) is produced in a microreactor, a monomer having an aromatic ring or a heterocycle is used as the first monomer, and reacted with an organolithium initiator as the initiator to produce the polymer (G). 2 A polymer block of a monomer having an aromatic ring or a heterocyclic ring (polymer block A 2 At one end of 1 The resulting product is an organolithium initiator residue, to which an organic group is attached. Next, after adjusting the reactivity of the growing end using a reaction modifier, a monomer containing a (meth)acrylate having a renewable protecting group on the anionic group is reacted as a second monomer to obtain a polymer block.

[0137] After this, the anionic group is regenerated by a deprotection reaction such as hydrolysis, thereby forming A 3 That is, a polymer block containing an anionic group is obtained.

[0138] A method for regenerating an ester bond of a protecting group capable of regenerating an anionic group into an anionic group by a deprotection reaction such as hydrolysis will be described in detail.

[0139] The hydrolysis reaction of the ester bond proceeds under both acidic and basic conditions, but the conditions vary slightly depending on the group having the ester bond. For example, when the group having the ester bond is a primary alkoxycarbonyl group such as a methoxycarbonyl group or a secondary alkoxycarbonyl group such as an isopropoxycarbonyl group, a carboxyl group can be obtained by hydrolysis under basic conditions. In this case, examples of basic compounds that can be used under basic conditions include metal hydroxides such as sodium hydroxide and potassium hydroxide.

[0140] In addition, when the group having an ester bond is a tertiary alkoxycarbonyl group such as a t-butoxycarbonyl group, a carboxyl group can be obtained by hydrolysis under acidic conditions. In this case, examples of acidic compounds that can be used under acidic conditions include mineral acids such as hydrochloric acid, sulfuric acid, and phosphoric acid; Brested acids such as trifluoroacetic acid; and Lewis acids such as trimethylsilyl triflate. The reaction conditions for hydrolysis of a t-butoxycarbonyl group under acidic conditions are disclosed in, for example, "Experimental Chemistry Lectures 16, Synthesis of Organic Compounds IV, 5th Edition, Edited by the Chemical Society of Japan."

[0141] Furthermore, as a method for converting a t-butoxycarbonyl group into a carboxyl group, a method using a cation exchange resin instead of the above-mentioned acid can be mentioned. Examples of the cation exchange resin include resins having acid groups such as a carboxyl group (-COOH) or a sulfo group (-SO3H) on the side chain of the polymer chain. Among these, a cation exchange resin having a sulfo group on the side chain of the resin and exhibiting strong acidity is preferable because it can accelerate the progress of the reaction. Examples of commercially available cation exchange resins that can be used in this embodiment include a strong acid cation exchange resin "Amberlite" manufactured by Organo Corporation. The amount of this cation exchange resin used is preferably in the range of 5 parts by mass to 200 parts by mass, more preferably in the range of 10 parts by mass to 100 parts by mass of the polymer represented by the general formula (1) because it can be effectively hydrolyzed.

[0142] In addition, when the group having an ester bond is a phenylalkoxycarbonyl group such as a benzyloxycarbonyl group, it can be converted to a carboxyl group by carrying out a hydrogenation reduction reaction. In this case, the reaction conditions are room temperature, in the presence of a palladium catalyst such as palladium acetate, and using hydrogen gas as a reducing agent, whereby the phenylalkoxycarbonyl group can be quantitatively regenerated to a carboxyl group.

[0143] As mentioned above, the reaction conditions for conversion to a carboxyl group differ depending on the type of group having an ester bond. For example, 3 The polymer obtained by copolymerization of t-butyl (meth)acrylate and n-butyl (meth)acrylate as the raw materials of A has t-butoxycarbonyl groups and n-butoxycarbonyl groups. Here, under acidic conditions where t-butoxycarbonyl groups are hydrolyzed, n-butoxycarbonyl groups are not hydrolyzed, so it is possible to selectively hydrolyze only the t-butoxycarbonyl groups and deprotect them to carboxyl groups. Therefore, 3 By appropriately selecting a monomer containing a (meth)acrylate having a renewable protecting group on the anionic group, which is the raw material monomer of 3 ) acid value can be adjusted.

[0144] In the polymer (G) represented by the general formula (1), 2 ) and polymer block (A 3 In order to improve the stability of the aqueous pigment dispersion in which the pigment is dispersed in water by the polymer (G), it is more advantageous to use a block copolymer in which the polymer blocks are regularly bonded in chunks of a certain length rather than a random copolymer in which the polymer blocks (A) are randomly arranged and bonded. The aqueous pigment dispersion is a raw material used in the production of ink, and is a liquid in which the pigment is dispersed in water at a high concentration by using the polymer (G). 2 ) and polymer block (A 3 ) molar ratio A 2 :A 3 is preferably in the range of 100:10 to 100:500, and A2 :A 3 It is more preferable for the ratio to be 100:10 to 100:450 in order to obtain an ink that can maintain the good ejection stability required when ejecting ink by an inkjet method, for example, and that can produce printed matter with even better color development, etc.

[0145] In the polymer (G) represented by the general formula (1), 2 The number of aromatic or heterocyclic monomers constituting the polymer block (A) is preferably in the range of 5 to 40, more preferably in the range of 6 to 30, and even more preferably in the range of 7 to 25. 3 The number of anionic groups constituting the copolymer is preferably in the range of 3 to 20, more preferably in the range of 4 to 17, and even more preferably in the range of 5 to 15. Polymer block (A 2 ) and polymer block (A 3 ) molar ratio A 2 :A 3 The polymer block (A 2 The number of moles of aromatic rings or heterocyclic rings constituting (A 3 When expressed in terms of the molar ratio of the number of moles of anionic groups constituting the copolymer, the molar ratio is preferably 100:7.5 to 100:400.

[0146] The acid value of the polymer (G) represented by general formula (1) is preferably from 40 mgKOH / g to 400 mgKOH / g, more preferably from 40 mgKOH / g to 300 mgKOH / g, and more preferably from 40 mgKOH / g to 190 mgKOH / g, which can maintain the good ejection stability required when ejecting ink by an inkjet system, for example, and is more preferable in terms of obtaining an ink that can produce printed matter that is even more excellent in terms of abrasion resistance, etc.

[0147] The acid value of the polymer in the present invention is determined by the same acid value measurement method as that used for measuring the fine particles of polymer (G).

[0148] In the ink, the anionic groups of the polymer (G) are preferably neutralized.

[0149] As the basic compound for neutralizing the anionic groups of the polymer (G), any of the known and commonly used basic compounds can be used, for example, inorganic basic substances such as alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and organic basic compounds such as ammonia, triethylamine, and alkanolamines.

[0150] The neutralization amount of the polymer (G) present in the aqueous pigment dispersion does not need to be 100% based on the acid value of the polymer. Specifically, the polymer (G) is neutralized so that the neutralization rate is preferably 20% to 200%, more preferably 80% to 150%.

[0151] <<Aqueous medium (C)>> As the aqueous medium (C), water alone or a mixed solvent of water and an organic solvent (F) described below can be used.

[0152] As the water, specifically, pure water or ultrapure water such as ion-exchanged water, ultrafiltered water, reverse osmosis water, distilled water, etc. can be used.

[0153] The aqueous medium (C) is preferably used in the range of 1% by mass to 50% by mass relative to the total amount of the ink, and it is particularly preferable to use it in the range of 10% by mass to 30% by mass in order to obtain an ink that has the high ejection stability required when ejected by an inkjet method and can produce clear printed matter.

[0154] Examples of the organic solvent (F) include ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, and methyl isobutyl ketone; alcohols such as methanol, ethanol, 2-propanol, 2-methyl-1-propanol, 1-butanol, and 2-methoxyethanol; ethers such as tetrahydrofuran, 1,4-dioxane, and 1,2-dimethoxyethane; glycols such as dimethylformamide, N-methylpyrrolidone, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, polyethylene glycol, and polypropylene glycol; diols such as butanediol, pentanediol, hexanediol, and diols of the same group as these; and lauric acid proton. Glycol esters such as propylene glycol; glycol ethers such as cellosolves including diethylene glycol monoethyl, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, propylene glycol ether, dipropylene glycol ether, and triethylene glycol ether; alcohols such as methanol, ethanol, isopropyl alcohol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, and other butyl alcohols, pentyl alcohol, and alcohols of the same family; sulfolane; lactones such as γ-butyrolactone; and lactams such as N-(2-hydroxyethyl)pyrrolidone, which can be used alone or in combination of two or more kinds.

[0155] In addition to the organic solvents mentioned above, it is preferable to use a water-soluble organic solvent (f1) having a boiling point of 100°C or more and 200°C or less and a vapor pressure of 0.5 hPa or more at 20°C as the organic solvent (F) in order to obtain a quick-drying effect in which the ejected droplets quickly dry on the fabric after landing on the surface of the fabric.

[0156] Examples of the water-soluble organic solvent (f1) include 3-methoxy-1-butanol, 3-methyl-3-methoxy-1-butanol, 3-methoxy-3-methyl-1-butyl acetate, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol-t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, dipropylene glycol dimethyl ether, 4-methoxy-4-methyl-2-pentanone, and ethyl lactate. Two or more of these may be used in combination.

[0157] Among these, it is preferable to use, as the water-soluble organic solvent (f1), a water-soluble organic solvent having a hydrogen bond term ΔH of HSP (Hansen Solubility Parameter) in the range of 6 to 20 in order to maintain good dispersion stability of the ink and to suppress deterioration of, for example, the ink ejection nozzle of an inkjet device due to the influence of the solvent contained in the ink.

[0158] Specific examples of water-soluble organic solvents having a hydrogen bond term of HSP within the above range include 3-methoxy-1-butanol, 3-methyl-3-methoxy-1-butanol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, ethylene glycol t-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol monopropyl ether, and more preferably 3-methoxy-1-butanol and 3-methyl-3-methoxy-1-butanol.

[0159] As an organic solvent that can be used in combination with the aqueous medium (C), in addition to the water-soluble organic solvent (f1) described above, or together with the water-soluble organic solvent (f1), a combination of propylene glycol (f2) and one or more organic solvents (f3) selected from the group consisting of glycerin, glycerin derivatives, diglycerin, and diglycerin derivatives is preferred in order to achieve both the effect of quick-drying the ink on the fabric and the effect of preventing the ink from drying or solidifying at the ink ejection orifice.

[0160] As the organic solvent (f3), for example, glycerin, diglycerin, polyglycerin, diglycerin fatty acid ester, polyoxypropylene (n) polyglyceryl ether represented by general formula (2), polyoxyethylene (n) polyglyceryl ether represented by general formula (3), etc. can be used alone or in combination of two or more kinds.

[0161] Among these, it is particularly preferable to use glycerin and polyoxypropylene (n) polyglyceryl ether (n=8 to 15) as the organic solvent (f3), as these have excellent setting properties for printed matter and are effective in preventing drying and solidification of the ink at the ink ejection orifices.

[0162] [ka]

[0163] In the general formulae (2) and (3), m, n, o and p each independently represent an integer of 1 to 10.

[0164] The organic solvent (F) is preferably used in the range of 1% by mass to 30% by mass based on the total amount of the ink, and it is particularly preferable to use it in the range of 5% by mass to 25% by mass, in order to achieve excellent setting properties of the printed matter and to prevent drying and solidification of the ink at the ink ejection orifices.

[0165] The water-soluble organic solvent (f1), propylene glycol (f2) and organic solvent (f3) are preferably used in such a manner that the mass ratio thereof [water-soluble solvent (f1) / propylene glycol (f2)] is in the range of 1 / 25 to 1 / 1, and it is particularly preferable to use them in the range of 1 / 20 to 1 / 1 in order to provide excellent setting properties for printed matter and to prevent drying and solidification of the ink at the ink ejection orifices.

[0166] The water-soluble organic solvent (f1), propylene glycol (f2), and organic solvent (f3) are preferably used in such a manner that the mass ratio thereof [propylene glycol (f2) / organic solvent (f3)] is in the range of 1 / 4 to 8 / 1, and it is particularly preferable to use them in the range of 1 / 2 to 5 / 1 in order to provide excellent setting properties for printed matter and to prevent drying and solidification of the ink at the ink ejection orifices.

[0167] <<Optional Additives>> In addition to the components described above, the ink of this embodiment may contain other optional additives, such as a surfactant (E), sugars, preservatives, viscosity adjusters, pH adjusters, chelating agents, antioxidants, and ultraviolet absorbers, as necessary.

[0168] The surfactant (E) can be used to improve the leveling properties of the ink by reducing the surface tension of the ink, etc. Furthermore, the surfactant (E) can prevent the occurrence of streaks in the printed matter by allowing the ink discharged from the discharge port of the inkjet head to smoothly wet and spread on the surface of the fabric after it lands on the fabric.

[0169] As the surfactant (E), various anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants, etc. can be used, and it is preferable to use an anionic surfactant or a nonionic surfactant.

[0170] Examples of the anionic surfactant include alkylbenzenesulfonates, alkylphenylsulfonates, alkylnaphthalenesulfonates, higher fatty acid salts, sulfate salts of higher fatty acid esters, sulfonates of higher fatty acid esters, sulfate salts and sulfonates of higher alcohol ethers, higher alkyl sulfosuccinates, polyoxyethylene alkyl ether carboxylates, polyoxyethylene alkyl ether sulfates, alkyl phosphates, and polyoxyethylene alkyl ether phosphates. Specific examples of these include dodecylbenzenesulfonates, isopropylnaphthalenesulfonates, monobutylphenylphenol monosulfonates, monobutylbiphenylsulfonates, and dibutylphenylphenol disulfonates.

[0171] Examples of nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, glycerin fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyglycerin fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkylamines, polyoxyethylene fatty acid amides, fatty acid alkylol amides, alkyl alkanol amides, acetylene glycol, oxyethylene adducts of acetylene glycol, polyethylene glycol polypropylene glycol block copolymers, and the like. Among these, polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, fatty acid alkylol amides, acetylene glycol, oxyethylene adducts of acetylene glycol, and polyethylene glycol polypropylene glycol block copolymers are preferred. Among these, acetylene glycol and oxyethylene adducts of acetylene glycol are more preferred since they reduce the contact angle of ink droplets with a recording medium and allow good printed matter to be obtained.

[0172] Other surfactants that can be used include silicone-based surfactants such as polysiloxane oxyethylene adducts; fluorine-based surfactants such as perfluoroalkyl carboxylates, perfluoroalkyl sulfonates, and oxyethylene perfluoroalkyl ethers; and biosurfactants such as spiculisporic acid, rhamnolipids, and lysolecithin.

[0173] As the surfactant (E), it is preferable to use one having an HLB value in the range of 4 to 20 in order to stably maintain the state in which the surfactant (E) is dissolved in the ink containing water as the main solvent.

[0174] The surfactant (E) is preferably used in the range of 0.001% by mass to 2% by mass, more preferably in the range of 0.001% by mass to 1.5% by mass, and even more preferably in the range of 0.5% by mass to 1.5% by mass, based on the total amount of the ink. An inkjet ink containing the surfactant (E) in the above range has good wettability of the discharged droplets on the fabric surface, has sufficient wet spread on the fabric, and is preferable in terms of preventing the occurrence of streaks in printed matter. Furthermore, an ink containing the surfactant (E) in the above range has the effect of improving the wettability and leveling property to the fabric.

[0175] Examples of sugars that can be used include monosaccharides and polysaccharides, such as glucose, mannose, fructose, ribose, xylose, arabinose, lactose, galactose, aldonic acid, glucitose, maltose, cellobiose, sucrose, trehalose, and maltotriose, as well as alginic acid and its salts, cyclodextrins, and celluloses.

[0176] Preservatives include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazolin-3-one (Proxel GXL, Proxel XL-2, Proxel LV, Proxel AQ, Proxel BD20, and Proxel DL, both from Arch Chemicals).

[0177] Examples of the viscosity modifier include mainly water-soluble natural or synthetic polymers such as carboxymethyl cellulose, sodium polyacrylate, polyvinylpyrrolidone, gum arabic, and starch.

[0178] Examples of the pH adjuster include collidine, imidazole, phosphoric acid, 3-(N-morpholino)propanesulfonic acid, tris(hydroxymethyl)aminomethane, and boric acid.

[0179] Chelating agents include ethylenediaminetetraacetic acid, ethylenediaminediacetic acid, nitrilotriacetic acid, 1,3-propanediaminetetraacetic acid, diethylenetriaminepentaacetic acid, N-hydroxyethylethylenediaminetriacetic acid, iminodiacetic acid, uramildiacetic acid, 1,2-diaminocyclohexane-N,N,N',N'-tetraacetic acid, malonic acid, succinic acid, glutaric acid, maleic acid, and salts thereof (including hydrates).

[0180] Examples of the antioxidant or ultraviolet absorber include allophanates such as allophanate and methyl allophanate, biurets such as biuret, dimethyl biuret, and tetramethyl biuret, L-ascorbic acid and its salts, Tinuvin 328, 900, 1130, 384, 292, 123, 144, 622, 770, 292, Irgacor 252, 153, Irganox 1010, 1076, 1035, and MD1024 manufactured by Ciba-Geigy, and oxides of lanthanides.

[0181] <<Ink properties>> The viscosity of the ink at 25°C is preferably 3 mPa·s to 20 mPa·s, more preferably 4 mPa·s to 15 mPa·s, and even more preferably 4 mPa·s to 12 mPa·s. If the viscosity of the ink is equal to or greater than the lower limit of the above range, the droplets ejected from the inkjet head have a sufficient volume, so that the deviation of the landing position on the fabric caused by the deflection of the flight can be reduced, and the occurrence of streaks in the printed matter can be effectively prevented. If the viscosity of the ink is equal to or less than the upper limit of the above range, the pressure loss during the liquid passing process can be kept low.

[0182] The viscosity of the ink can be measured, for example, using a cone-plate type rotational viscometer equivalent to an E-type viscometer under the following conditions. Measurement equipment: TVE-25 type viscometer (manufactured by the company, TVE-25 L) Calibration standard solution: JS20 Measurement temperature: 32℃ Rotation speed: 10~100rpm Injection volume: 1200μL

[0183] The surface tension of the ink is preferably 20 mN / m to 40 mN / m at 25°C, more preferably 25 mN / m to 38 mN / m, and even more preferably 28 mN / m to 36 mN / m. If the surface tension of the ink is equal to or greater than the lower limit of the above range, the ink has good wettability on the surface of the fabric, and has sufficient wet spread after landing. As a result, the deviation of the landing position on the fabric caused by the flight deflection of the ink is reduced, and the occurrence of streaks in the printed matter can be effectively prevented. If the surface tension of the ink is equal to or less than the upper limit of the above range, the ink has excellent storage stability and ejection stability.

[0184] The surface tension of the ink can be measured, for example, using an automatic surface tensiometer that applies the Wilhelmy method under the following conditions. According to the Wilhelmy method, both static and dynamic surface tensions can be measured, but the surface tension of the ink in this embodiment indicates the value of the static surface tension. Measuring device: Automatic surface tensiometer (Kyowa Interface Science Co., Ltd., CBVP-Z type) Measurement temperature: 25℃ Probe: Platinum plate

[0185] From the viewpoint of ejection stability, the dissolved oxygen concentration in the ink is preferably 5 ppm or less, more preferably 3 ppm or less, and even more preferably 1 ppm or less. The dissolved oxygen concentration in the ink can be measured, for example, by the Ostwald method or the like, or can be measured by an oxygen concentration meter such as a galvanic cell type or a colorimetric analysis method or the like.

[0186] The pH of the ink is preferably 7.0 to 11.0, more preferably 7.5 to 10.0, and even more preferably 8.0 to 9.5. If the pH of the ink is equal to or higher than the lower limit of the above range, the storage stability and ejection stability of the ink can be improved, and the ink can be improved in wet spread, print density, and water fastness when printed on a fabric that is easily or poorly ink absorbent. If the pH of the ink is equal to or lower than the upper limit of the above range, deterioration of the components (e.g., ink ejection port, ink flow path, etc.) constituting the ink application or ejection device can be suppressed, and the effects of the ink adhering to the skin can be reduced. The pH of the ink can be measured using a general pH measuring device or the like.

[0187] <<Ink manufacturing method>> When the colorant (B) is a pigment, the ink of this embodiment can be produced by producing an aqueous pigment dispersion containing the pigment at a high concentration, and mixing the aqueous medium (C), the binder resin (A), the surfactant (E), and other additives as necessary.

[0188] Examples of methods for producing the aqueous pigment dispersion include the following methods (1) to (3). (1) A method of preparing an aqueous pigment dispersion by adding a pigment to a mixture containing a dispersing resin and water, and then dispersing the pigment in the mixture using a stirring and dispersing device. (2) A method in which a pigment and a dispersing resin are kneaded using a kneading machine such as a two-roll mill or a mixer, water and, if necessary, an organic solvent that is miscible with water are added to the resulting kneaded mixture, and an aqueous pigment dispersion is prepared using a stirring and dispersing device. (3) A method in which a pigment is added to a solution obtained by dissolving a dispersing resin in an organic solvent that is compatible with water, such as methyl ethyl ketone or tetrahydrofuran, and the like, and then the pigment is dispersed in the organic solution using a stirring and dispersing device, and then phase inversion emulsification is carried out using an aqueous medium, and the organic solvent is then distilled off to prepare an aqueous pigment dispersion.

[0189] The kneading machine is not particularly limited, and for example, a Henschel mixer, a pressure kneader, a Banbury mixer, an intensive mixer, a planetary mixer, a butterfly mixer, etc. can be used.

[0190] As the stirring and dispersing device, for example, an ultrasonic homogenizer, a high-pressure homogenizer, a paint shaker, a ball mill, a roll mill, a sand mill, a sand grinder, a Dyno Mill, a Dispermat, an SC Mill, a Nanomizer, etc. can be used alone or in combination of two or more kinds.

[0191] As the aqueous pigment dispersion, it is preferable to use one that contains 5% by mass to 60% by mass of pigment based on the total amount of the aqueous pigment dispersion in order to obtain an ink that can form printed matter with high image density and has excellent dispersion stability, and it is more preferable to use an aqueous pigment dispersion that contains 10% by mass to 50% by mass of pigment.

[0192] Furthermore, since coarse particles contained in the aqueous pigment dispersion can cause deterioration of image characteristics, it is preferable to use an aqueous pigment dispersion from which coarse particles have been removed by centrifugation, filtration, or the like before or after production of the ink.

[0193] When producing an aqueous pigment dispersion, the dispersion step may be followed by an impurity removal step using ion exchange treatment or ultrafiltration, followed by post-treatment. Ion exchange treatment can remove ionic substances such as cations and anions (divalent metal ions, etc.), and ultrafiltration treatment can remove dissolved impurities (residual substances from pigment synthesis, excess components in the dispersion liquid composition, resins not adsorbed to organic pigments, contaminants, etc.). A known ion exchange resin is used for the ion exchange treatment. A known ultrafiltration membrane is used for the ultrafiltration treatment, and either a normal type or a type with double capacity may be used.

[0194] The ink obtained by the above-mentioned manufacturing method is ejected onto the surface of a fabric mainly by an ink-jet printing method, and since the ink is used for printing onto a fabric, it can be suitably used as a so-called textile printing agent.

[0195] <Hollow fiber sheet> The hollow fiber sheet of this embodiment is composed of a plurality of hollow fibers. The number of hollow fibers constituting the hollow fiber sheet is not particularly limited and can be selected arbitrarily according to the physical properties of the ink. As the hollow fibers, any material, membrane shape, and membrane form can be used as long as the hollow fiber is a hollow fiber-shaped membrane that allows gas to pass but not liquid to pass, and hollow fibers that have been used in hollow fiber modules for degassing can be used. Examples of materials for the hollow fibers include polyolefin resins such as polypropylene and poly(4-methylpentene-1), silicon resins such as polydimethylsiloxane and its copolymers, and fluorine-based resins such as PTFE and vinylidene fluoride. The shape of the side wall (membrane) of the hollow fiber can be any of a porous membrane, a microporous membrane, and a homogeneous membrane (non-porous membrane) that does not have porosity. As the membrane form, any of a symmetric membrane (homogeneous membrane) in which the chemical or physical structure of the entire membrane is homogeneous, and an asymmetric membrane (heterogeneous membrane) in which the chemical or physical structure of the membrane differs depending on the part of the membrane can be used. Asymmetric membranes, or heterogeneous membranes, are membranes that have a non-porous dense layer and a porous layer, but the dense layer may be formed anywhere in the membrane, such as on the surface of the membrane or inside the porous membrane. These heterogeneous membranes also include so-called composite membranes with different chemical structures and multi-layer membranes such as three-layer structures. In particular, heterogeneous membranes using poly(4-methylpentene-1) resin are preferred because they have a dense layer that blocks liquids. It is also preferred that the dense layer is formed on the outer surface of the hollow fiber.

[0196] The outer diameter of the hollow fiber is preferably 0.01 to 1.0 mm. If the outer diameter of the hollow fiber is within the above range, the strength is easy to manufacture, and the specific surface area of ​​the hollow fiber is sufficiently large, which tends to increase the degassing efficiency. Here, the diameter refers to the diameter when the cross section is circular, and when the cross section is not circular, the diameter refers to the diameter when the cross section is replaced with a circle of the same area. The outer diameter of a hollow fiber can be measured by observing the cross section of the hollow fiber with an electron microscope.

[0197] The hollow fiber sheet may be a sheet in which hollow fibers are woven into a mesh pattern. However, it is preferable to use a hollow fiber sheet in which a large number of hollow fibers are all arranged approximately parallel to each other, because this allows the liquid to come into even contact with all of the hollow fibers when ink is passed through them, thereby enabling efficient liquid passage processing.

[0198] The hollow fiber sheet is not used for conventional ink degassing, but is used as a filter. Therefore, the hollow fiber sheet is not particularly limited as long as it can be used as a filter, and for example, a commercially available hollow fiber module for degassing may be used as it is. Examples of commercially available hollow fiber modules for degassing include the SEPAREL series from DIC Corporation. When liquid is passed using a hollow fiber membrane module for degassing, ink is supplied to the inside of the hollow fiber membrane from an ink supply port at an end of the module under near atmospheric pressure, and the ink is discharged from an ink outlet at the other end of the module.

[0199] A commercially available hollow fiber module for deaeration usually has a cylindrical core and a hollow fiber sheet around it. The cylindrical core serves to maintain the rigidity of the hollow fiber module for deaeration and to function as a support base for the hollow fibers, but it is known that the cylindrical core may increase pressure loss and make it difficult to reduce the size of the device. For this reason, although there is no particular limitation, the hollow fiber sheet of the present embodiment is particularly preferably one that does not have a cylindrical core and has a shape in which hollow fibers are bundled into a cylindrical shape, which can reduce pressure loss and reduce size while maintaining rigidity.

[0200] A method for producing a hollow fiber sheet having a shape in which hollow fibers are bundled into a cylindrical shape is not particularly limited, and examples thereof include a method comprising a step of winding a hollow fiber sheet containing a large number of hollow fibers around a temporary core to hold it in a cylindrical shape, supplying a resin to one end of the hollow fiber sheet held in a cylindrical shape, bonding one ends of the large number of hollow fibers lined up at one end of the hollow fiber sheet to each other and sealing the holes of each hollow fiber opening at one end of the hollow fiber sheet, covering the hollow fiber sheet with a housing before the resin hardens, and removing the temporary core from the hollow fiber sheet after the resin hardens.

[0201] According to the above-mentioned manufacturing method, before removing the temporary core from the sheet held in a cylindrical shape, a resin is supplied to one end of the cylindrical sheet, and one ends of the many hollow fibers arranged at one end of the sheet are bonded to each other and the holes of each hollow fiber opening at one end of the sheet are sealed. As a result, when a hollow fiber sheet is manufactured using a bundle of hollow fibers in which all of the many hollow fibers are arranged approximately parallel to each other, a central hole parallel to the length direction of the hollow fibers can be formed in the cylindrical hollow fiber sheet. In conventional hollow fiber modules for deaeration, the central hole of the hollow fiber sheet is secured by a core as a support base, but in the hollow fiber sheet obtained by the above-mentioned manufacturing method, which has a shape in which the hollow fibers are bundled into a cylindrical shape, the central hole can be easily secured without providing a core. As a result, a hollow fiber sheet that reduces pressure loss and meets the demand for miniaturization can be obtained.

[0202] Although the above-mentioned manufacturing method is shown as an example of the method for manufacturing the hollow fiber sheet of this embodiment, the method is not particularly limited, and the hollow fiber sheet can be appropriately manufactured using a conventionally known method.

[0203] (Printing process) The printing step of the present embodiment includes a step of printing the ink after the liquid passing step onto a fabric by inkjet printing.

[0204] The method for printing on the fabric can be a conventionally known inkjet printing method, for example, a method of printing using an ink circulation type inkjet head, etc. can be used. An example of a printing device equipped with an ink circulation type inkjet head is a printing device equipped with a head having an ink circulation structure in which an ink inflow path and an ink outflow path are provided in addition to the ink ejection nozzles, and the ink flowing out from the outflow path passes through the inflow path and is supplied to the inkjet head again. A printing device in which the hollow fiber sheet of the present embodiment is provided in the middle of the circulation structure can be preferably used.

[0205] The manufacturing method of this embodiment is particularly suitable for printing on fabrics. The printed matter obtained by the manufacturing method of this embodiment has excellent print quality and excellent water fastness, and is therefore suitable for use in textile products for home textiles such as clothing, curtains, covers, and sheets. EXAMPLES

[0206] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. In the examples, the terms "parts", "%", and the like are based on mass unless otherwise specified.

[0207] (Preparation of Dispersion Resin (P-1)) A hexane solution of BuLi and a styrene solution in which styrene had been dissolved in tetrahydrofuran in advance were introduced into a T-shaped micromixer M1 from tube reactors P1 and P2 shown in FIG. 1, and a polymer was obtained by living anionic polymerization.

[0208] Next, the polymer obtained in the above step was transferred to the T-shaped micromixer M2 through the tube reactor R1 shown in FIG. 1, and the growing end of the polymer was trapped by a reaction modifier (α-methylstyrene (α-MeSt)) introduced from the tube reactor P3.

[0209] Next, a tert-butyl methacrylate solution in which tert-butyl methacrylate was dissolved in tetrahydrofuran was introduced from the tube reactor P4 shown in Figure 1 into the T-shaped micromixer M3, and a continuous living anionic polymerization reaction was carried out with the trapped polymer transferred through the tube reactor R2. Thereafter, the living anionic polymerization reaction was quenched by supplying methanol to produce a block copolymer (PA-1) composition.

[0210] When producing the block copolymer (PA-1) composition, the reaction temperature was set to 24° C. by immersing the entire microreactor shown in FIG. 1 in a thermostatic chamber.

[0211] The molar ratio of the monomers constituting the block copolymer (PA-1) obtained by the above method is The ratio of BuLi to styrene / α-methylstyrene / tert-butyl methacrylate was 1.0 / 12.0 / 1.3 / 8.1.

[0212] The obtained block copolymer (PA-1) composition was hydrolyzed by treatment with a cation exchange resin, and then distilled under reduced pressure. The obtained solid was pulverized to obtain a powdered dispersion resin (P-1) with a weight average molecular weight of 2710 and an acid value of 145.

[0213] (Preparation of aqueous pigment dispersion) 150 parts by mass of Mitsubishi Carbon Black #960 as a pigment, 45 parts by mass of dispersion resin (P-1), 150 parts by mass of triethylene glycol, and 17 parts by mass of 34% by mass aqueous potassium hydroxide solution were charged into a 1.0 L intensive mixer (Nippon Airich Co., Ltd.) and kneaded for 60 minutes with a rotor peripheral speed of 2.94 m / s and a pan peripheral speed of 1 m / s.

[0214] Next, 450 parts by mass of ion-exchanged water was gradually added to the kneaded material in the intensive mixer container while continuing to stir, and then 208.5 parts by mass of ion-exchanged water was further added and mixed to obtain an aqueous pigment dispersion with a pigment concentration of 15.0% by mass.

[0215] (Preparation of urethane resin composition (1)) In a nitrogen-substituted vessel equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 500 parts by mass of polycarbonate polyol (number average molecular weight 2000) obtained by reacting 1,6-hexanediol with methyl carbonate, 36.5 parts by mass of 2,2-dimethylolpropionic acid, and 436 parts by mass of methyl ethyl ketone were added, and 183.5 parts by mass of dicyclohexylmethane diisocyanate was used, and the mixture was reacted at 80°C for 3 hours to obtain a methyl ethyl ketone solution of a urethane prepolymer having an isocyanate group at the molecular end. 41.3 parts by mass of triethylamine was added to the methyl ethyl ketone solution of the urethane prepolymer obtained above to neutralize the carboxyl group in the urethane prepolymer, and then 1504 parts by mass of water was added. Next, 5.2 parts by mass of hydrazine was added and the mixture was reacted. After the reaction was completed, methyl ethyl ketone was removed under reduced pressure at a temperature of 40°C to 60°C, and water was added to adjust the concentration, thereby obtaining a urethane resin composition (1) containing polyurethane having a weight average molecular weight of 150,000 and an acid value of 21 mgKOH / g, with a non-volatile content of 35 mass%, in which the urethane resin was dispersed in an aqueous medium.

[0216] (Preparation of urethane resin composition (2)) In a nitrogen-substituted vessel equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 500 parts by mass of polycarbonate polyol (number average molecular weight 2000) obtained by reacting 1,6-hexanediol with methyl carbonate, 37.7 parts by mass of 2,2-dimethylolpropionic acid, and 420 parts by mass of methyl ethyl ketone were added and mixed uniformly. Next, 92.4 parts by mass of tolylene diisocyanate was added, followed by 0.1 parts by mass of dibutyltin dilaurate, and the mixture was reacted at 80°C for 7 hours to obtain an organic solvent solution of polyurethane (PUD-1) (acid value 35 mgKOH / g) with a weight average molecular weight of 40,000. Thereafter, the mixture was cooled to 50°C, 29.8 parts by mass of triethylamine and 2,069 parts by mass of water were added, and methyl ethyl ketone was removed under reduced pressure at a temperature of 40°C to 60°C. Water was then added to adjust the concentration, thereby obtaining a urethane resin composition (2) having a non-volatile content of 23% by mass in which the urethane resin (PUD-1) was dispersed in an aqueous medium.

[0217] (Ink and Print Preparation) Inks and prints were prepared as follows.

[0218] [Example 1] <Preparation of Water-Based Ink> An aqueous ink was obtained by mixing 25 parts by mass of the aqueous pigment dispersion, 20 parts by mass of urethane resin composition (1), 1 part by mass of Surfynol 440 (manufactured by EVONIK, an acetylene-based surfactant), 23 parts by mass of glycerin, 1 part by mass of triethylene glycol, 1 part by mass of 3-methyl-1,5-pentanediol, 0.2 parts by mass of ACTICIDE B-20 (manufactured by Thor Japan Co., Ltd.) as a preservative, and 28.8 parts by mass of ion-exchanged water.

[0219] <Filter filtration> The resulting water-based ink was filtered through a polypropylene cartridge filter having a pore size of 0.5 μm.

[0220] <Passing liquid through hollow fiber sheet under normal pressure and preparation of printed matter> Next, an inkjet printer equipped with a hollow fiber module for deaeration (SEPAREL EF-G2, DIC Corporation) was used to pass the aqueous ink through the inkjet head under normal pressure, filling the ink with the ink. The distance (gap) from the surface (x) having the ink ejection ports of the inkjet head to the position (y) where the perpendicular line assumed to the surface (x) intersects with the fabric was set to 3 mm. Cotton broadcloth (manufactured by Ikisen Co., Ltd.) was used as the fabric. After wiping the nozzle surface of the inkjet head, a 100% solid image was printed on the fabric at a driving frequency of 10 kHz, then dried at 100°C for 1 minute, and then heat-treated at 150°C for 5 minutes to obtain a print.

[0221] [Examples 2 and 3] A printed matter was obtained in the same manner as in Example 1, except that the composition of the water-based ink was changed to the values ​​shown in Table 1.

[0222] [Comparative Example 1] A printed matter was obtained in the same manner as in Example 1, except that an inkjet printer not equipped with a deaeration hollow fiber module (SEPAREL EF-G2, DIC Corporation) was used and no aqueous ink was passed through the inkjet printer under normal pressure.

[0223] [Comparative Example 2] A printed matter was obtained in the same manner as in Example 1, except that the aqueous ink was passed under a reduced pressure of -85 kPa instead of under normal pressure.

[0224] (evaluation) The volume average particle diameters of the water-based inks in Examples 1 to 3 and Comparative Examples 1 and 2 were measured, and the viscosity stability and continuous ejection property were also evaluated as follows.

[0225] [Measurement of volume average particle size] Using a dynamic light scattering particle size distribution analyzer ("Microtrack Particle Size Distribution Meter UPA-ST150" manufactured by Nikkiso Co., Ltd.), the dispersed particle size of the pigment was measured from the light scattering information of the particles, and the volume average particle size was calculated. The results are shown in Table 1.

[0226] [Evaluation of viscosity stability] 20 mL of the water-based ink was sealed in a glass container and left to stand at 60° C. for 4 weeks, after which the rate of change from the initial viscosity was evaluated according to the following criteria. The results are shown in Table 1. ○: The change in viscosity of the water-based ink after standing for 4 weeks is less than ±5% △: The change in viscosity of the water-based ink after leaving it for 4 weeks is between ±5% and ±10% ×: The change in viscosity of the water-based ink after standing for 4 weeks is 10% or more

[0227] The viscosity and surface tension of the water-based ink were measured by the following methods.

[0228] The viscosity of the water-based ink was measured using a cone-plate type rotational viscometer equivalent to an E-type viscometer under the following conditions. Measurement equipment: TVE-25 type viscometer (manufactured by the company, TVE-25 L) Calibration standard solution: JS20 Measurement temperature: 25℃ Rotation speed: 10~100rpm Injection volume: 1200μL The static surface tension of the water-based ink was measured under the following conditions using an automatic surface tensiometer employing the Wilhelmy method. Measuring device: Automatic surface tensiometer (Kyowa Interface Science Co., Ltd., CBVP-Z type) Measurement temperature: 25℃ Probe: Platinum plate

[0229] [Evaluation of continuous discharge] Using a Ricoh head (MH5421), ink was ejected from one of four rows of 320 nozzles at a drive frequency of 20 kHz for up to 30 minutes, and the percentage of nozzles that caused missing or twisted ejection when observing flying droplets was evaluated according to the following criteria. The results are shown in Table 1. ◯: The percentage of nozzles that caused missing or twisted ink is less than 10%. △: The percentage of nozzles that caused missing or twisted ink is between 10% and 20%. ×: The percentage of nozzles that caused missing or twisted discharge was 20% or more.

[0230] [Table 1]

[0231] Comparing Examples 1 to 3 with Comparative Example 1, it is found that by passing the liquid through a hollow fiber sheet under near normal pressure, excellent continuous ejection properties are achieved in inkjet printing. In addition, the printed matter obtained by the methods of Examples 1 to 3 all had excellent appearance. [Explanation of symbols]

[0232] 1: T-shaped micro mixer M1 2: T-shaped micro mixer M2 3: T-shaped micro mixer M3 4: Tube Reactor R1 5: Tube Reactor R2 6: Tube Reactor R3 7: Tube reactor P1 for pre-cooling 8: Tube reactor P2 for pre-cooling 9: Tube reactor P3 for pre-cooling 10: Tube reactor P4 for pre-cooling

Claims

1. A method for producing a printed matter in which a water-based ink is printed on a fabric, comprising the steps of: a liquid passing step of passing an aqueous ink through the hollow fiber sheet under a pressure of 70 to 100 kPa in a space on the opposite side of the ink passage across the hollow fiber sheet; a printing step of printing the aqueous ink after the liquid passing step on a fabric by an inkjet printing method, the water-based ink contains a urethane resin having an acid value of 10 to 40 mgKOH / g; The method for producing a printed matter, wherein the material of the hollow fiber sheet is selected from the group consisting of polypropylene, poly(4-methylpentene-1), silicone-based resins, and fluorine-based resins.

2. A method for producing a printed matter as described in claim 1, wherein in the liquid passing step, the aqueous ink is passed through a hollow fiber sheet under normal pressure.

3. 3. The method for producing a printed matter according to claim 1, wherein in the passing step, a passing speed of the aqueous ink through the hollow fiber sheet is 0.1 to 500 mL / min.

4. A method for producing a printed matter described in any one of claims 1 to 3, wherein the material of the hollow fiber sheet is poly(4-methylpentene-1).

5. The method for producing a printed matter according to any one of claims 1 to 4, wherein the aqueous ink has a viscosity of 20 mPa·s or less and a surface tension of 20 mN / m to 40 mN / m.

6. The hollow fiber sheet includes a plurality of hollow fibers, The method for producing a printed matter according to any one of claims 1 to 5, wherein the hollow fibers have an outer diameter of 0.01 to 1.0 mm.

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