Solvent inkjet ink and method for producing printed material

Abstract

To provide a solvent inkjet ink capable of forming an image that excels in all of water resistance, ethanol rub resistance, and adhesion to substrates.SOLUTION: A solvent inkjet ink contains a pigment, a pigment dispersant with an acid value of 10 mgKOH / g or less, a binder resin, and an organic solvent. The binder resin contains a (meth)acrylic resin with an acid value of more than 10 mgKOH / g and 30 mgKOH / g or less, and a polyester resin with an acid value of 5 mgKOH / g or less. The mass ratio A of the polyester resin with an acid value of 5 mgKOH / g or less to the (meth)acrylic resin with an acid value of more than 10 mgKOH / g and 30 mgKOH / g or less is less than 1.00.SELECTED DRAWING: None

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE Embodiments of the present invention relate to solvent inkjet inks and methods for producing printed products. [Background technology]

[0002] Inkjet recording is a method of ejecting highly fluid inkjet ink as droplets from a fine nozzle to record an image on a substrate placed opposite the nozzle. This method has been rapidly spreading in recent years because it allows low-noise, high-speed printing. Inks used in this type of inkjet recording method include aqueous inks that contain water as the main solvent, ultraviolet-curable inks (UV inks) that contain a high content of polymerizable monomers as the main component, and hot-melt inks (solid inks) that contain a high content of wax as the main component, as well as so-called non-aqueous inks that contain a non-aqueous solvent as the main solvent. Non-aqueous inks can be classified into solvent inks (solvent-based inks) whose main solvent is a volatile organic solvent, and oil-based inks (oil-based inks) whose main solvent is a low-volatility or non-volatile organic solvent. Solvent inks dry on the substrate mainly due to the evaporation of the organic solvent, whereas oil-based inks dry mainly due to penetration into the substrate.

[0003] Inkjet printing is sometimes performed on plastic substrates such as polyvinyl chloride resin, olefin resin, and the like.

[0004] Patent Document 1 describes an ink containing at least one of diethylene glycol monomethyl ether and diethylene glycol monoethyl ether and diethylene glycol ethyl methyl ether as an inkjet recording ink having low odor and excellent adhesion to polyvinyl chloride resin substrates.

[0005] Patent Document 2 describes a non-aqueous inkjet ink that uses a vinyl chloride-vinyl acetate copolymer resin with a specific molecular weight distribution, as a non-aqueous inkjet ink that is mainly suitable for printing on vinyl chloride substrates.

[0006] Patent Document 3 describes that an ink composition containing a binder resin having an acid value of 10 mgKOH / g or less, a basic dispersant, a pigment, and an organic solvent can be preferably used for polyvinyl chloride resin sheets. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2012-233086 A [Patent Document 2] JP 2018-59106 A [Patent Document 3] JP 2010-24352 A Summary of the Invention [Problem to be solved by the invention]

[0008] An object of an embodiment of the present invention is to provide a solvent inkjet ink capable of forming an image that is excellent in all of water resistance, alcohol resistance, and adhesion to a substrate. [Means for solving the problem]

[0009] One embodiment of the present invention relates to a solvent inkjet ink comprising: a pigment; a pigment dispersant having an acid value of 10 mgKOH / g or less; a binder resin; and an organic solvent, wherein the binder resin comprises a (meth)acrylic resin having an acid value of more than 10 mgKOH / g and less than 30 mgKOH / g; and a polyester resin having an acid value of 5 mgKOH / g or less, and a mass ratio A of the polyester resin having an acid value of 5 mgKOH / g or less to the (meth)acrylic resin having an acid value of more than 10 mgKOH / g and less than 30 mgKOH / g is less than 1.00. Another embodiment of the present invention relates to a method of producing a printed article comprising applying the above-described solvent inkjet ink to a substrate by an inkjet process. Effect of the Invention

[0010] According to an embodiment of the present invention, it is possible to provide a solvent inkjet ink capable of forming an image that is excellent in all of water resistance, alcohol resistance, and adhesion to a substrate. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the present invention will be described using embodiments. The examples in the following embodiments are not intended to limit the present invention. In the following description, the solvent inkjet ink may be simply referred to as "solvent ink" or "ink".

[0012] <Solvent inkjet ink> The solvent inkjet ink according to an embodiment includes a pigment, a pigment dispersant having an acid value of 10 mgKOH / g or less (hereinafter may be referred to as "pigment dispersant D"), a binder resin, and an organic solvent, the binder resin includes a (meth)acrylic resin having an acid value of more than 10 mgKOH / g and less than 30 mgKOH / g (hereinafter may be referred to as "(meth)acrylic resin M"), and a polyester resin having an acid value of 5 mgKOH / g or less (hereinafter may be referred to as "polyester resin P"), and the mass ratio A of the polyester resin having an acid value of 5 mgKOH / g or less to the (meth)acrylic resin having an acid value of more than 10 mgKOH / g and less than 30 mgKOH / g is less than 1.00.

[0013] When the solvent inkjet ink of the embodiment is used, it is possible to form an image that is excellent in water resistance, alcohol resistance, and adhesion to a substrate. The solvent inkjet ink of the embodiment also has excellent storage stability. Without being bound by any particular theory, the reason for this is presumed to be as follows.

[0014] The (meth)acrylic resin can contribute to improving the adhesion of the image to the substrate. When the binder resin contains a (meth)acrylic resin, it is easy to improve the adhesion to a plastic substrate such as an olefin substrate. On the other hand, the (meth)acrylic resin may not have sufficient water resistance and alcohol resistance, but the polyester resin can contribute to improving the water resistance and alcohol resistance of the image. However, the compatibility between the (meth)acrylic resin and the polyester resin may be low, and therefore the dry resin film may become uneven. If the dry resin film is uneven, the water resistance and alcohol resistance of the image may decrease, or the film may become weak, resulting in a decrease in the adhesion of the image to the substrate. In addition, if the compatibility between the resins is low and the ink is in an uneven mixed state, the storage stability of the ink also tends to decrease. The present inventors have found that when a (meth)acrylic resin ((meth)acrylic resin M) having an acid value of more than 10 mgKOH / g and not more than 30 mgKOH / g is used as the (meth)acrylic resin, and a polyester resin (polyester resin P) having an acid value of 5 mgKOH / g or less is used as the polyester resin, and the amounts of these resins in the ink are such that the mass ratio A of polyester resin P to (meth)acrylic resin M is less than 1.00, it is possible for these resins to be present in the ink in a state of good compatibility. In addition, when the acid value of the (meth)acrylic resin is greater than 10 mgKOH / g, the compatibility with the polyester resin is easily improved. On the other hand, when the acid value of the (meth)acrylic resin is 30 mgKOH / g or less, the water resistance and alcohol resistance of the (meth)acrylic resin itself tend to be good, and the adhesion of the (meth)acrylic resin itself to the substrate also tends to be good. In addition, when the acid value of the polyester resin is 5 mgKOH / g or less, the water resistance and alcohol resistance of the polyester resin tend to be good.

[0015] Also, for example, when a large amount of pigment dispersant is used, the pigment dispersant and the binder resin may not be sufficiently compatible when the ink is dried on the substrate. In this way, when the compatibility between the pigment dispersant and the binder resin is low, the strength of the dried film may decrease when the ink is dried on the substrate, and the durability of the image may decrease. In addition, when the compatibility between the pigment dispersant and the binder resin is low, the storage stability of the ink containing them tends to be low. The present inventors have found that when a pigment dispersant D having an acid value of 10 mgKOH / g or less is used as the pigment dispersant, the compatibility with the binder resin containing the polyester resin P and the (meth)acrylic resin M can be improved.

[0016] In this way, when (meth)acrylic resin M, polyester resin P and pigment dispersant D are used and the mass ratio of (meth)acrylic resin M to polyester resin P is set to a predetermined value, it is possible to form an image that is excellent in water resistance, alcohol resistance and adhesion to the substrate, and a solvent ink that also has excellent storage stability can be obtained.

[0017] The ink may include a pigment. As the pigment, organic pigments such as azo pigments, phthalocyanine pigments, polycyclic pigments, and dye lake pigments, and inorganic pigments such as carbon black and metal oxides can be used. As the azo pigment, soluble azo lake pigments, insoluble azo pigments, and condensed azo pigments can be used. As the phthalocyanine pigment, metal phthalocyanine pigments and metal-free phthalocyanine pigments can be used. As the polycyclic pigment, quinacridone pigments, perylene pigments, perinone pigments, isoindoline pigments, isoindolinone pigments, dioxazine pigments, thioindigo pigments, anthraquinone pigments, quinophthalone pigments, metal complex pigments, and diketopyrrolopyrrole (DPP) can be used. As the carbon black, furnace carbon black, lamp black, acetylene black, channel black, and the like can be used. As the metal oxide, titanium oxide, zinc oxide, and the like can be used. These pigments may be used alone or in combination of two or more.

[0018] From the viewpoints of ejection stability and storage stability, the average particle diameter of the pigment particles in the ink is preferably 500 nm or less, more preferably 300 nm or less, even more preferably 200 nm or less, even more preferably 150 nm or less, and even more preferably 100 nm or less, as a volume-based average value in the particle size distribution measured by the dynamic light scattering method. From the viewpoint of color development, the average particle diameter of the pigment particles in the ink is preferably 50 nm or more, as a volume-based average value in the particle size distribution measured by the dynamic light scattering method. The average particle diameter of the pigment particles in the ink may be, for example, 50 to 500 nm, 50 to 300 nm, 50 to 200 nm, 50 to 150 nm, or 50 to 100 nm, as a volume-based average value in the particle size distribution measured by the dynamic light scattering method.

[0019] The pigment may be blended in the ink as a pigment dispersion. The pigment dispersion may be any dispersion in which the pigment can be dispersed in a solvent and in which the pigment is in a dispersed state in the ink. For example, a dispersion in which the pigment is dispersed in a dispersion medium using a pigment dispersant, a dispersion in which a microencapsulated pigment in which the pigment is coated with a resin is dispersed in a dispersion medium, or the like may be used.

[0020] From the viewpoints of print density and ink viscosity, the content of the pigment is preferably 0.1 to 20 mass% relative to the total amount of the ink, more preferably 0.1 to 15 mass%, even more preferably 0.5 to 10 mass%, and even more preferably 1 to 10 mass%, and may be, for example, 1 to 5 mass%.

[0021] The pigment dispersion form may be a so-called capsule pigment in which the pigment is coated with an oil-insoluble resin, or a dispersion in which colored resin particles are dispersed with a pigment dispersant, but a dispersion in which the pigment dispersant is directly adsorbed onto the pigment surface and dispersed is preferred.

[0022] In order to stably disperse the pigment in the ink, the ink preferably contains a pigment dispersant together with the pigment. As the pigment dispersant, a pigment dispersant having an acid value of 10 mgKOH / g or less (pigment dispersant D) can be preferably used from the viewpoints of storage stability of the ink and water resistance and alcohol resistance of the image.

[0023] From the viewpoint of improving compatibility with the binder resin, the acid value of the pigment dispersant D is preferably 10 mgKOH / g or less, more preferably 8 mKOH / g or less. On the other hand, the acid value of the pigment dispersant D may be, for example, 1 mKOH / g or more. The acid value of the pigment dispersant D may be, for example, 1 to 10 mgKOH / g or 1 to 8 mgKOH / g.

[0024] From the viewpoint of the adsorption to the pigment surface, it is preferable that the pigment dispersant D has an amine value. From the viewpoint of the adsorption to the pigment, the amine value of the pigment dispersant D is more preferably 8 mgKOH / g or more, and even more preferably 10 mgKOH / g or more. On the other hand, from the viewpoint of further improving the compatibility with the binder resin, the amine value of the pigment dispersant D is preferably 20 mgKOH / g or less, and more preferably 15 mgKOH / g or less. The amine value of the pigment dispersant D may be, for example, 8 to 20 mgKOH / g, 10 to 20 mgKOH / g, or 10 to 15 mgKOH / g.

[0025] In this disclosure, the acid value is expressed as the number of milligrams (mg) of potassium hydroxide required to neutralize the acidic components contained in 1 g of sample, and the amine value is expressed as the number of milligrams (mg) of potassium hydroxide equivalent to the amount of hydrochloric acid or perchloric acid required to neutralize the basic components contained in 1 g of sample. The acid value and amine value can be measured in accordance with JIS K2501:2003 "Petroleum products and lubricants -- Test method for neutralization number."

[0026] Examples of the pigment dispersant include hydroxyl group-containing carboxylate esters, salts of long-chain polyaminoamides and high molecular weight acid esters, salts of high molecular weight polycarboxylates, salts of long-chain polyaminoamides and polar acid esters, high molecular weight unsaturated acid esters, copolymers of vinylpyrrolidone and long-chain alkenes, modified polyurethanes, modified polyacrylates, polyether ester-type anionic surfactants, polyoxyethylene alkyl phosphate esters, polyester polyamines, etc. As the pigment dispersant D, it is preferable to use, among these pigment dispersants, a pigment dispersant having an acid value of 10 mgKOH / g or less.

[0027] The pigment dispersant D may be appropriately synthesized, or a commercially available product may be used. Examples of commercially available pigment dispersants D include "Solsperse 75000", "Solsperse 75500", "Solsperse 32500", "Solsperse 32550", "Solsperse 32600", "Solsperse 34750", "Solsperse 35100", "Solsperse 35200", and "Solsperse 37500" manufactured by Lubrizol Japan Co., Ltd., and "DISPERBYK-163", "DISPERBYK-168", "DISPERBYK-182", "DISPERBYK-185", "DISPERBYK-2009", and "DISPERBYK-2013" manufactured by BYK-Chemie Japan Co., Ltd. These may be used alone or in combination of two or more types.

[0028] The pigment dispersant D is preferably contained in a mass ratio of 0.2 to 1.0 per pigment 1. The pigment dispersant D is preferably contained in an amount of 0.1 to 10 mass % relative to the total amount of the ink, and more preferably 0.5 to 5 mass %.

[0029] The ink may contain, as a binder resin, a (meth)acrylic resin ((meth)acrylic resin M) having an acid value greater than 10 mgKOH / g and less than or equal to 30 mgKOH / g, and a polyester resin (polyester resin P) having an acid value of less than or equal to 5 mgKOH / g. The binder resin is preferably an oil-soluble resin.

[0030] The (meth)acrylic resin may be a resin containing a methacrylic unit, a resin containing an acrylic unit, or a resin containing both of these units. The (meth)acrylic resin may contain units other than the acrylic unit and / or the methacrylic unit, for example, a styrene unit, etc. Examples of the (meth)acrylic resin include a polymer of an acrylic acid ester, a polymer of a methacrylic acid ester, or a copolymer of these with styrene, etc.

[0031] The weight average molecular weight of the (meth)acrylic resin is preferably from 1,000 to 200,000, and more preferably from 10,000 to 100,000. In the present disclosure, the weight average molecular weight of a resin is a value obtained by gel permeation chromatography (GPC) analysis in terms of polystyrene.

[0032] The acid value of the (meth)acrylic resin M is preferably higher than 10 mgKOH / g, more preferably 11 mgKOH / g or more, and even more preferably 15 mgKOH / g or more, from the viewpoint of improving the compatibility with the polyester resin P. The acid value of the (meth)acrylic resin M is preferably 30 mgKOH / g or less, and more preferably 25 mgKOH / g or less, from the viewpoint of improving the water resistance and alcohol resistance of the (meth)acrylic resin M. The acid value of the (meth)acrylic resin M may be, for example, greater than 10 mgKOH / g and not greater than 30 mgKOH / g, from 11 to 30 mgKOH / g, or from 15 to 25 mgKOH / g. From the viewpoint of more efficiently enhancing the water resistance and alcohol resistance of the image, it is preferable that the (meth)acrylic resin M has no amine value.

[0033] From the viewpoint of image durability, the glass transition point (Tg) of the (meth)acrylic resin M is preferably 50° C. or higher, more preferably 60° C. or higher. The glass transition point of the (meth)acrylic resin M may be, for example, 50 to 150° C., or 60 to 150° C. When the glass transition point of the (meth)acrylic resin is within such a range, the printed image is likely to have better water resistance, alcohol resistance, and adhesion to the substrate. In the present disclosure, the glass transition point of the resin is a value measured according to differential scanning calorimetry (DSC) unless otherwise specified.

[0034] Commercially available (meth)acrylic resins M include, for example, "Neocryl B-735", "Neocryl B-809", "Neocryl B-819", "Neocryl B-841", and "Neocryl B-851" manufactured by Covestro, and "Dianale BR-77" manufactured by Mitsubishi Chemical Corporation (all trade names).

[0035] The (meth)acrylic resin M may be used alone or in combination of two or more. The (meth)acrylic resin M may be, for example, 0.1% by mass or more, 1% by mass or more, or 2% by mass or more, based on the total amount of the ink. On the other hand, the (meth)acrylic resin M may be, for example, 20% by mass or less, 10% by mass or less, or 5% by mass or less, based on the total amount of the ink. The (meth)acrylic resin M may be, for example, 0.1 to 20% by mass, 1 to 10% by mass, or 2 to 5% by mass or more, based on the total amount of the ink.

[0036] The polyester resin may include a structure obtained by dehydration polycondensation of a polybasic acid and a polyhydric alcohol, which are monomers. For example, the polyester resin may be obtained by dehydration polycondensation of a polycarboxylic acid and a polyalcohol, which are monomers, by a conventional method, and a desired weight average molecular weight can be obtained by adjusting the type and amount of the monomer. As the polyester resin P, a polyester resin having an acid value of 5 mgKOH / g or less can be used.

[0037] Examples of polybasic acids used in polyester resins include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 9,10-anthracenedicarboxylic acid, and diphenic acid; aromatic oxycarboxylic acids such as p-oxybenzoic acid and p-(hydroxyethoxy)benzoic acid; aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid; aliphatic unsaturated polyvalent carboxylic acids such as fumaric acid, maleic acid, itaconic acid, mesaconic acid, cyclohexenedicarboxylic acid, dimer acid, trimer acid, and tetramer acid; alicyclic dicarboxylic acids such as hexahydrophthalic acid and tetrahydrophthalic acid; and polyvalent carboxylic acids such as trimellitic acid, trimesic acid, and pyromellitic acid. In addition, a monobasic acid may be used in combination with a polybasic acid. Examples of monobasic acids include benzoic acid, chlorobenzoic acid, bromobenzoic acid, parahydroxybenzoic acid, t-butylbenzoic acid, naphthalenecarboxylic acid, 3-methylbenzoic acid, 4-methylbenzoic acid, salicylic acid, thiosalicylic acid, phenylacetic acid, naphthalenecarboxylic acid, anthracenecarboxylic acid, t-butylnaphthalenecarboxylic acid, and cyclohexylaminocarbonylbenzoic acid.

[0038] Examples of polyhydric alcohols used in the polyester resin include aliphatic diols such as ethylene glycol, propylene glycol, 1,3-propanediol, 2,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 2,2,4-trimethyl-1,3-pentanediol, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol; aliphatic polyhydric alcohols such as triols and tetraols such as trimethylolethane, trimethylolpropane, glycerin, and pentaerythritol; alicyclic polyhydric alcohols such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, spiroglycol, bisphenol A, hydrogenated bisphenol A, tricyclodecanediol, and tricyclodecanedimethanol; and aromatic polyhydric alcohols such as paraxylene glycol, metaxylene glycol, ortho-xylene glycol, and 1,4-phenylene glycol. Furthermore, a monohydric alcohol may be used in combination with a portion of the polyhydric alcohol.

[0039] The viscosity average molecular weight of the polyester resin P is preferably 1000 or more, more preferably 1500 or more, and even more preferably 2000 or more. The viscosity average molecular weight of the polyester resin P may be, for example, 50000 or less, 30000 or less, or 20000 or less. The viscosity average molecular weight of the polyester P may be, for example, 1000 to 50000, 1500 to 30000, or 2000 to 20000. In the present disclosure, the viscosity average molecular weight of a resin is a value calculated from the intrinsic viscosity of a diluted polymer solution measured using a capillary viscometer.

[0040] From the viewpoint of image durability, the acid value of the polyester resin P is preferably 5 mgKOH / g or less, and more preferably 3 mgKOH / g or less. The acid value of the polyester resin P may be, for example, 0 mgKOH / g or more, for example, 0 to 5 mgKOH / g, or 0 to 3 mgKOH / g.

[0041] From the viewpoint of more efficiently enhancing the water resistance and alcohol resistance of the image, it is preferable that the polyester resin P does not have an amine value.

[0042] From the viewpoint of improving compatibility with the pigment dispersant, the hydroxyl value of the polyester resin is preferably 10 mgKOH / g or more, more preferably 15 mgKOH / g or more, and may be, for example, 20 mgKOH / g or more. When the compatibility with the pigment dispersant is improved, the viscosity of the dispersion can be made better. In this disclosure, the hydroxyl value is expressed as the number of milligrams of potassium hydroxide required to neutralize the acetic acid bonded to the hydroxyl group when 1 g of a sample is acetylated. The hydroxyl value can be determined according to JIS K0070:1992 "Testing methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products".

[0043] Commercially available polyester resins P include, for example, "ELITEL UE-3320", "ELITEL UE-9820", "ELITEL UE-3350", "ELITEL UE-3380", "ELITEL UE-3300", and "ELITEL UE-3980" manufactured by Unitika Ltd., and "BYLON 220", "BYLON 226", "BYLON 802", "BYLON 885", and "BYLON GK-810" manufactured by Toyobo Co., Ltd. (all trade names).

[0044] The polyester resin P may be used alone or in combination of two or more kinds. The polyester resin P may be, for example, 0.01% by mass or more, 0.1% by mass or more, or 0.2% by mass or more, based on the total amount of the ink. On the other hand, the polyester resin P may be, for example, 5% by mass or less, 2% by mass or less, or 1% by mass or less, based on the total amount of the ink. For example, the polyester resin P may be 0.01 to 5% by mass, 0.1 to 2% by mass, or 0.2 to 1% by mass, based on the total amount of the ink.

[0045] The mass ratio A of the polyester resin P to the (meth)acrylic resin M (polyester resin P / (meth)acrylic resin M) may be greater than 0. The mass ratio A is preferably less than 1.00. The mass ratio A is, for example, preferably 0.01 or more and less than 1.00, more preferably 0.03 or more and less than 0.50, and even more preferably 0.05 or more and less than 0.20. From the viewpoint of the water resistance and alcohol resistance of the image, the mass ratio A is preferably 0.01 or more, more preferably 0.03 or more, and even more preferably 0.05 or more. From the viewpoint of the compatibility between the (meth)acrylic resin M and the polyester resin P, and the compatibility between the pigment dispersant D and the polyester resin P, and from the viewpoint of the water resistance, alcohol resistance, and adhesion to the substrate of the image, the mass ratio A is preferably less than 1.00. From the viewpoint of better storage stability of the ink and adhesion of the image to the substrate, the mass ratio A is more preferably less than 0.50, and even more preferably less than 0.20.

[0046] The mass ratio B of the polyester resin P to the pigment dispersant D (polyester resin P / pigment dispersant D) is preferably 0.10 or more and 0.50 or less, more preferably 0.15 or more and 0.35 or less, and even more preferably 0.20 or more and 0.30 or less. From the viewpoint of further improving the water resistance and alcohol resistance of the image, the mass ratio B is preferably 0.10 or more, more preferably 0.15 or more, and even more preferably 0.20 or more. From the viewpoint of better storage stability of the ink and adhesion of the image to the substrate, the mass ratio B is preferably 0.50 or less, more preferably 0.35 or less, and even more preferably 0.30 or less.

[0047] The ink may further contain a binder resin other than the polyester resin P and the (meth)acrylic resin M. As such a binder resin, for example, a vinyl chloride resin such as a vinyl chloride-vinyl acetate resin, a urethane resin, or the like, which is used in a typical ink composition, can be used. Commercially available polyvinyl chloride-vinyl acetate resins include, for example, the vinyl chloride-vinyl acetate resins "Solvine CL," "Solvine CNL," "Solvine C5R," "Solvine TA3," and "Solvine TA5R" manufactured by Nissin Chemical Industry Co., Ltd., and the vinyl chloride-vinyl acetate resins "VINNOL E15 / 45," "VINNOL H14 / 36," "VINNOL H40 / 43," "VINNOL E15 / 45M," and "VINNOL E15 / 40M" manufactured by Wacker Co. (all are product names).

[0048] The total amount of the (meth)acrylic resin M and the polyester resin P is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, based on the total amount of the binder resin in the ink. The total amount of the binder resin in the ink is preferably 1 to 10% by mass, and more preferably 3 to 8% by mass, based on the total amount of the ink.

[0049] The organic solvent is not particularly limited, and examples thereof include ketone-based solvents, alcohol-based solvents, glycol ether-based solvents, and acetate-based solvents. From the viewpoint of suppressing odor during printing work, it is preferable to use an organic solvent having a boiling point of 100° C. or more, and more preferable to use an organic solvent having a boiling point of 150° C. or more. From the viewpoint of drying property, it is preferable to use an organic solvent having a boiling point of 250° C. or less, and more preferable to use an organic solvent having a boiling point of 200° C. or less. It is preferable that the organic solvent having a boiling point of 150° C. or more and 200° C. or less accounts for 70% by mass or more of the total organic solvents.

[0050] Examples of glycol ether solvents include diethylene glycol diethyl ether, diethylene glycol ethyl methyl ether, diethylene glycol isopropyl methyl ether, diethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, diethylene glycol monoethyl ether, and dipropylene glycol monomethyl ether. Examples of acetate-based solvents include ethyl cellosolve acetate, ethylene glycol diacetate, 3-methoxybutyl acetate, ethylene glycol monobutyl ether acetate, and cyclohexyl acetate. These organic solvents may be used alone or in combination of two or more.

[0051] The organic solvent is contained in an amount of preferably 60 to 95% by mass, more preferably 65 to 90% by mass, and even more preferably 70 to 90% by mass, based on the total amount of the ink.

[0052] The ink preferably contains a surfactant. For example, from the viewpoint of improving the wetting and spreading of the ink even on a hydrophobic substrate surface and increasing the drying speed to form a good image, the ink preferably contains a surfactant. Examples of the surfactant include silicone-based surfactants, fluorine-based surfactants, and polyoxyethylene derivatives, which are nonionic surfactants.

[0053] Examples of silicone surfactants include polyester-modified silicone, polyether-modified silicone, etc. Examples of commercially available silicone surfactants include "BYK-307", "BYK-313", "BYK-330", "BYK-333", "BYK-342", "BYK-370", "BYK-377", "BYK-378", "BYK-3550", "BYK-3565", "BYK-3750", "BYK-3761", "BYK-3762", "BYK-3764", and "BYK-SILCLEAN 3700" manufactured by BYK Japan Co., Ltd., and "Silface SAG005" and "Silface SAG008" manufactured by Nissin Chemical Industry Co., Ltd. (all trade names).

[0054] Examples of commercially available fluorosurfactants include "BYK-340" manufactured by BYK Japan K.K., and "Surflon S-211," "Surflon S-131," "Surflon S-132," "Surflon S-141," "Surflon S-144," and "Surflon S-145" manufactured by AGC Inc. (all trade names).

[0055] As the polyoxyethylene derivative, it is preferable to use an acetylene glycol surfactant. Examples of commercially available acetylene glycol surfactants include "Surfynol 82", "Surfynol 104", "Surfynol 465", "Surfynol 485", and "Surfynol TG" manufactured by Evonik Industries Co., Ltd., and "Olfine STG" and "Olfine E1004" manufactured by Nissin Chemical Industry Co., Ltd. (all trade names).

[0056] From the viewpoints of continuous ejection property during printing and color development of images, it is preferable that the ink contains a silicone-based surfactant.

[0057] The surfactants may be used alone or in combination of two or more. The amount of the surfactant is preferably 0.05 to 2% by mass, and more preferably 0.1 to 1% by mass, based on the total amount of the ink.

[0058] The ink may contain various additives depending on the application, etc. Examples of the additives include UV absorbers, light stabilizers, antioxidants, plasticizers, etc.

[0059] The method for producing the ink is not particularly limited, but in one method, the ink can be produced by mixing and stirring each component all at once or in portions. Specifically, the ink can be produced by dispersing all the components in a dispersing machine such as a beads mill, either all at once or in portions, and dispersing the components, and, if desired, passing the mixture through a filtering machine such as a membrane filter.

[0060] In the method for producing the ink, for example, a pigment dispersion may be prepared by mixing and stirring the pigment with a pigment dispersant D and an organic solvent or the like in advance to disperse the pigment. In preparing the pigment dispersion, for example, a polyester resin P may be added. When the pigment dispersant D and the polyester resin P have good compatibility, they contribute to the dispersion stabilization of the pigment having a hydrophobic surface, further improving the storage stability of the ink and making it possible to more effectively suppress a decrease in the durability of the image.

[0061] The solvent ink is preferably an inkjet ink.

[0062] The suitable range of viscosity of the inkjet ink varies depending on the nozzle diameter of the ejection head of the inkjet recording system, the ejection environment, etc., but in general, it is preferably 5 to 30 mPa·s at 23° C., more preferably 5 to 15 mPa·s, and even more preferably 8 to 13 mPa·s. In the present disclosure, the ink viscosity is a value measured at 23° C. As a viscosity measuring device, for example, a "Rheometer MCR302" manufactured by Anton Paar Japan Ltd. can be used.

[0063] The printing method using the inkjet ink is not particularly limited, and may be any method such as a piezoelectric method, an electrostatic method, a thermal method, etc. When an inkjet recording device is used, it is preferable to eject the ink according to one embodiment from an inkjet head based on a digital signal, and to cause the ejected ink droplets to adhere to a substrate.

[0064] In this embodiment, the substrate is not particularly limited, and may be plain paper, coated paper, special paper, or other printing paper, cloth, inorganic sheet, film, OHP sheet, or an adhesive sheet having an adhesive layer on the back surface of the substrate. For example, the solvent ink of the embodiment may be preferably used for plastic substrates such as vinyl chloride resin and olefin resin. Examples of olefin resins include polypropylene resin. Such plastic substrates may be absorbent substrates capable of absorbing the applied ink, such as substrates having an ink receiving layer, or may be non-absorbent substrates not having an ink receiving layer. The ink of the embodiment may be preferably used for substrates into which the ink does not easily penetrate. For example, the solvent ink of the embodiment may be preferably used for synthetic paper made of olefin resin such as polypropylene resin.

[0065] <Manufacturing method of printed matter> A method for producing a printed matter according to an embodiment can include applying a solvent ink to a substrate by an inkjet method. The solvent ink according to the embodiment described above can be used as the solvent ink. The substrate can be one of the substrates described above as substrates suitable for use with the solvent ink according to the embodiment.

[0066] In the step of applying the solvent ink to the substrate, the solvent ink is preferably applied to the substrate by an inkjet method. The inkjet method is not particularly limited, and may be any method such as a piezoelectric method, an electrostatic method, or a thermal method.

[0067] The amount of solvent ink applied to the substrate is 1 to 500 g / m 2 is preferable, and 3 to 100 g / m 2 More preferably, 5 to 50 g / m 2 More preferably, 10 to 30 g / m 2 is most preferred.

[0068] The method for producing a printed matter may include steps such as a pretreatment step and a heating step.

[0069] The present disclosure includes the following embodiments. <1> The pigment comprises a pigment dispersant having an acid value of 10 mgKOH / g or less, a binder resin, and an organic solvent, the binder resin includes a (meth)acrylic resin having an acid value of more than 10 mgKOH / g and not more than 30 mgKOH / g, and a polyester resin having an acid value of not more than 5 mgKOH / g; a mass ratio A of the polyester resin having an acid value of 5 mgKOH / g or less to the (meth)acrylic resin having an acid value of more than 10 mgKOH / g and not more than 30 mgKOH / g is less than 1.00. <2> a mass ratio B of the polyester resin having an acid value of 5 mgKOH / g or less to the pigment dispersant having an acid value of 10 mgKOH / g or less is 0.10 or more and 0.50 or less; <1> 2. The solvent ink-jet ink according to claim 1 . <3> The mass ratio A is 0.05 or more and less than 0.20. <1> or <2> 2. The solvent ink-jet ink according to claim 1 . <4> The (meth)acrylic resin has a glass transition point of 60° C. or higher. <1> ~ <3> 2. The solvent ink-jet ink according to claim 1 . <5> <1> ~ <4> 13. A method for producing a printed matter, comprising applying the solvent inkjet ink according to any one of claims 1 to 12 onto a substrate by an inkjet method. EXAMPLES

[0070] The present invention will be described in detail below with reference to examples, but the present invention is not limited to the following examples.

[0071] <Production of pigment dispersion> The materials shown in Tables 1 to 3 were weighed out into a beaker in the proportions shown in Tables 1 to 3, premixed, and then transferred to a plastic container with a lid. Zirconia beads with a diameter of 0.8 mm were added thereto, and dispersed for 30 minutes using a rocking mill RM-05 (manufactured by Seiwa Giken Co., Ltd.), after which the beads were separated from the dispersion to produce pigment dispersions 1 to 15 with a pigment concentration of 20 mass %.

[0072] Details of the materials listed in Tables 1 to 3 are shown below.

[0073] (Pigments) Pigment 1: Carbon black, "#950" manufactured by Mitsubishi Chemical Corporation Pigment 2: Cyan pigment, "Fastogen Blue 5452K" manufactured by DIC Corporation Pigment 3: Magenta pigment, "Fastogen Super Magenta JM02" manufactured by DIC Corporation Pigment 4: Yellow pigment, "Bayscript Yellow 4GF" manufactured by LANXESS KK

[0074] (Pigment dispersant) Pigment dispersant 1: Pigment dispersant, Solsperse 75000 (acid value 4.0±2.0 mgKOH / g) manufactured by Lubrizol Japan, active ingredient 100% by mass Pigment dispersant 2: Pigment dispersant, Solsperse 32500 (acid value 6.3±1.3 mgKOH / g) manufactured by Lubrizol Japan, active ingredient 40% by mass Pigment dispersant 3: Pigment dispersant, Solsperse 32550 (acid value 6.3±1.3 mgKOH / g) manufactured by Lubrizol Japan, active ingredient 50% by mass Pigment dispersant 4: Pigment dispersant, BYK Japan Co., Ltd. "DISPERBYK-2014" (acid value 0 mgKOH / g), active ingredient 100% by mass Pigment dispersant 5: Pigment dispersant, Solsperse 32000 (acid value 15.5±2.5 mgKOH / g) manufactured by Lubrizol Japan, active ingredient 100% by mass

[0075] (binder resin) Polyester resin 1: "Elitel UE-3350" manufactured by Unitika Ltd. (acid value 1 mgKOH / g) Polyester resin 2: "Elitel UE-3300" manufactured by Unitika Ltd. (acid value 1 mgKOH / g) Polyester resin 3: "Elitel UE-3380" manufactured by Unitika Ltd. (acid value 1 mgKOH / g) Polyester resin 4: "Elitel UE-9820" manufactured by Unitika Ltd. (acid value 3 mg KOH / g) Polyester resin 5: "Vylon GK-810" manufactured by Toyobo Co., Ltd. (acid value 5 mg KOH / g) Polyester resin 6: "Elitel UE-9885" (acid value 22 mgKOH / g) manufactured by Unitika Ltd.

[0076] (Organic solvent) Organic solvent 1: Diethylene glycol diethyl ether, manufactured by Tokyo Chemical Industry Co., Ltd. Organic solvent 2: Propylene glycol diacetate, manufactured by Tokyo Chemical Industry Co., Ltd. Organic solvent 3: Diacetone alcohol, manufactured by Tokyo Chemical Industry Co., Ltd. Organic solvent 4: Hexyl propionate, manufactured by Tokyo Chemical Industry Co., Ltd.

[0077] [Table 1]

[0078] [Table 2]

[0079] [Table 3]

[0080] <Ink manufacturing> The materials shown in Tables 4 to 7 were premixed in the ratios shown in Tables 4 to 7, then dispersed in a homogenizer for 1 minute, and then filtered through a membrane filter with a pore size of 3 μm to obtain inks 1 to 29.

[0081] Details of the raw materials listed in Tables 4 to 7 are shown below.

[0082] (Pigment Dispersion) Pigment Dispersions 1 to 15: Prepared as above

[0083] (polyester resin) Polyester resins 1 to 6: The same as polyester resins 1 to 6 used in the production of pigment dispersions

[0084] ((Meth)acrylic resin) (Meth)acrylic resin 1: "Neocryl B-809" manufactured by Covestro (acid value 19 mgKOH / g, glass transition point 80°C) (Meth)acrylic resin 2: "Dianal BR-77" manufactured by Mitsubishi Chemical Corporation (acid value 18 mgKOH / g, glass transition point 84°C (estimated value according to the FOX formula)) (Meth)acrylic resin 3: "Neocryl B-841" manufactured by Covestro (acid value 25 mgKOH / g, glass transition point 69°C) (Meth)acrylic resin 4: "Neocryl B-735" manufactured by Covestro (acid value 11 mgKOH / g, glass transition point 74°C) (Meth)acrylic resin 5: "Neocryl B-819" manufactured by Covestro (acid value 16 mgKOH / g, glass transition point 49°C) (Meth)acrylic resin 6: Covestro "Neocryl B-890" (acid value 75 mg KOH / g) (Meth)acrylic resin 7: "Dianal BR-83" (acid value 0 mgKOH / g) manufactured by Mitsubishi Chemical Corporation

[0085] (Organic solvent) Organic solvents 1 to 4: The same as the organic solvents 1 to 4 used in the production of the pigment dispersion

[0086] (Surfactant) Surfactant: Silicone surfactant, BYK-3565 manufactured by BYK Japan Co., Ltd.

[0087] [Table 4]

[0088] [Table 5]

[0089] [Table 6]

[0090] [Table 7]

[0091] <Storage stability of ink> The storage stability of inks 1 to 29 was evaluated. Specifically, the evaluation was performed as follows. A 20 mL glass bottle was filled with ink in an amount that filled about 90% of the internal volume of the glass bottle, and the glass bottle was capped and stored in a thermostatic chamber at 60° C. for two weeks, after which the viscosity of the ink was measured. The rate of change in the viscosity of the ink after this two-week storage from the viscosity of the ink immediately after preparation (initial viscosity) was determined, and the storage stability of the ink was evaluated according to the following criteria. A: Viscosity change rate from initial viscosity is within ±3.0% B: Viscosity change rate from initial viscosity is greater than ±3.0% and within ±5.0% C: Viscosity change rate from initial viscosity is greater than ±5.0% and is within ±10.0% D: Viscosity change rate from the initial viscosity is greater than ±10.0%

[0092] <Creating printed matter> In order to evaluate the water resistance, alcohol resistance, and adhesion to the substrate of the image, prints were produced using inks 1 to 29. Specifically, the prepared inks 1 to 29 were introduced into the head of a commercially available large format inkjet printer, and the ink was ejected at a rate of 20 g / m. 2 After setting the settings as above, a solid monochrome image was printed on a polypropylene synthetic paper ("New Yupo FGS110" manufactured by Yupo Corporation).

[0093] <Water resistance of images> A water-soaked cotton swab was rubbed 50 times against the coating of the solid image area of ​​the printed matter obtained above with a load of 100 g. The condition of the rubbed area and the rubbed cotton swab were visually observed, and the water resistance of the image was evaluated according to the following criteria. A: No coloring of the cotton swabs or fading of the printed surface. B: The cotton swab was stained, but no discoloration was observed on the printed surface. C: The cotton swab was stained and discoloration was observed on the printed surface. D: The cotton swab was discolored, the printed surface was discolored, and the base material of the peeled part was visible.

[0094] <Alcohol resistance of images> A cotton swab soaked in 100% ethanol was applied with a load of 100 g and rubbed five times against the coating film of the solid image area of ​​the printed matter obtained above. The condition of the rubbed area and the rubbed cotton swab were visually observed, and the alcohol resistance of the image was evaluated according to the following criteria. A: No coloring of the cotton swabs or fading of the printed surface. B: The cotton swab was stained and the printed surface was slightly discolored, but not noticeable. C: The cotton swab was stained and discoloration was observed on the printed surface. D: The cotton swab was discolored, the printed surface was discolored, and the base material of the peeled part was visible.

[0095] <Adhesion of image to substrate> Tape was applied to the solid image area of ​​the print obtained above, and after the tape was peeled off, the image and the tape were observed, and the adhesion of the image to the substrate was evaluated according to the following criteria. A: No peeling on the image, no stains on the tape after peeling B: No noticeable peeling in the image, tape slightly dirty after peeling C: The image shows obvious peeling, and the tape is still dirty after peeling. D: The image on the taped area has almost completely peeled off and transferred to the tape after it is removed.

[0096] Tables 8 to 11 show the evaluation results of the storage stability of the ink, the water resistance of the image, the alcohol resistance of the image, and the adhesion of the image to the substrate. Tables 8 to 11 also show, for each ink, the amount (% by mass) of pigment dispersant D (pigment dispersant with an acid value of 10 mgKOH / g or less) relative to the total amount of ink, the amount (% by mass) of polyester resin P (polyester resin with an acid value of 5 mgKOH / g or less) relative to the total amount of ink, the amount (% by mass) of (meth)acrylic resin M ((meth)acrylic resin with an acid value greater than 10 mgKOH / g and less than 30 mgKOH / g) relative to the total amount of ink, mass ratio A (mass ratio of polyester resin P to (meth)acrylic resin M), and mass ratio B (mass ratio of polyester resin P to pigment dispersant D).

[0097] [Table 8]

[0098] [Table 9]

[0099] [Table 10]

[0100] [Table 11]

[0101] As shown in the table, Examples 1 to 23 showed good results in terms of the storage stability of the ink, the water resistance of the image, the alcohol resistance of the image, and the adhesion of the image to the substrate.

[0102] In Comparative Example 1, in which ink 24 containing no polyester resin was used, the water resistance and alcohol resistance of the image were insufficient. In Comparative Example 2, in which Ink 25 containing a pigment dispersant with a high acid value was used instead of Pigment Dispersant D, the storage stability of the ink was reduced. This is presumably because sufficient compatibility between the pigment dispersant and the polyester resin was not obtained. Furthermore, the water resistance and alcohol resistance of the image were also reduced. In Comparative Example 3, in which the ink 26 containing a polyester resin with a high acid value instead of the polyester resin P was used, the water resistance and alcohol resistance of the image were reduced. In Comparative Example 4, in which ink 27 containing a (meth)acrylic resin with a high acid value instead of (meth)acrylic resin M was used, the water resistance, alcohol resistance, and adhesion to the substrate of the image were reduced. In Comparative Example 5, in which ink 28 containing a (meth)acrylic resin having no acid value was used instead of (meth)acrylic resin M, the storage stability of the ink was reduced. This is presumably because sufficient compatibility with the polyester resin was not obtained. In addition, the water resistance, alcohol resistance, and adhesion to the substrate of the image were also reduced. This is also considered to be due to the influence of poor compatibility. In Comparative Example 6, in which ink 29 having a high mass ratio A (mass ratio of polyester resin P to (meth)acrylic resin M) was used, the water resistance, alcohol resistance, and adhesion to the substrate of the image were reduced. This is believed to be because sufficient compatibility between the (meth)acrylic resin and the pigment dispersant was not obtained.

Claims

1. The ink contains a pigment, a pigment dispersant having an acid value of 10 mgKOH / g or less, a binder resin, and an organic solvent, the binder resin includes a (meth)acrylic resin having an acid value of more than 10 mgKOH / g and not more than 30 mgKOH / g, and a polyester resin having an acid value of not more than 5 mgKOH / g, a mass ratio A of the polyester resin having an acid value of 5 mgKOH / g or less to the (meth)acrylic resin having an acid value of more than 10 mgKOH / g and not more than 30 mgKOH / g is less than 1.

00.

2. 2. The solvent ink-jet ink according to claim 1, wherein a mass ratio B of the polyester resin having an acid value of 5 mgKOH / g or less to the pigment dispersant having an acid value of 10 mgKOH / g or less is 0.10 or more and 0.50 or less.

3. The solvent ink-jet ink according to claim 1 , wherein the mass ratio A is equal to or greater than 0.05 and less than 0.

20.

4. The solvent ink-jet ink according to claim 1 , wherein the (meth)acrylic resin has a glass transition temperature of 60° C. or higher.

5. A method for producing a printed matter, comprising applying the solvent inkjet ink according to any one of claims 1 to 4 to a substrate by an inkjet method.

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