Pretreatment liquid, ink set, and printed matter

Abstract

The present invention provides a pretreatment liquid for use with an aqueous inkjet ink, which can provide a printed matter having excellent print quality, has excellent initial ejection stability and continuous ejection stability, and also has good blending stability during production. In addition to the above-mentioned effects, the pretreatment liquid preferably also provides excellent abrasion resistance to the printed matter. [Solution] The pretreatment liquid contains a coagulant, a resin, a water-soluble organic solvent, and water, and is used together with an aqueous inkjet ink, wherein the resin contains a nonionic resin (R), the water-soluble organic solvent contains a water-soluble organic solvent (S1) having an octanol / water partition coefficient of -1.60 or more and less than -0.20, and a water-soluble organic solvent (S2) having an octanol / water partition coefficient of -0.20 to 1.00, and the ratio of the content of the nonionic resin (R) to the content of the water-soluble organic solvent (S2) is specified.

Description

[Technical field]

[0001] The present invention relates to a pretreatment liquid, an ink set containing the pretreatment liquid, and a printed matter produced using the ink set. [Background technology]

[0002] Inkjet printing is a method of ejecting and depositing ink droplets from a fine nozzle onto a substrate to obtain a printed matter on which characters and / or images are printed. The above-mentioned "image" includes a solid image (an image printed at 100% coverage so as to completely cover the surface of the substrate) and seamless images such as a checkered pattern image. In comparison with conventional plate-based printing methods such as offset printing and gravure printing, inkjet printing has the following characteristics: the printing device can be made smaller, colorization is easy, and the print quality is less affected by the printing environment. Therefore, inkjet printing is being increasingly used not only for office and home use but also for industrial use. In addition, while inks used in inkjet printing in industrial use have traditionally been solvent inks or ultraviolet-curing inks, there is an increasing demand for water-based inks containing water as the main component due to considerations of the safety and health of printing personnel.

[0003] Furthermore, in recent years, when printing aqueous inks on low-permeability substrates such as coated paper, art paper, and lightly coated paper, and non-permeability substrates such as plastic substrates by inkjet printing, a pretreatment liquid is used for the purpose of improving the print quality (see, for example, Patent Documents 1 and 2). Examples of the "improvement of print quality" include prevention of blanking (a phenomenon in which the substrate surface is exposed due to poor wetting and spreading of the ink in printed matter with a high printing rate) and color mixing and bleeding. In addition, the pretreatment liquid includes a component (agglomerant) that can intentionally cause the aggregation of solid components (pigments and / or resins) present in the aqueous inkjet ink and the thickening of the aqueous inkjet ink, and by adding a resin different from the agglomerant, it is also possible to improve the properties of the printed matter, such as improving abrasion resistance and imparting substrate adhesion.

[0004] On the other hand, since the amount of pretreatment liquid applied can be controlled according to the printing rate of the aqueous inkjet ink, it is easy to adjust the print quality, and the printing device can be made compact. Therefore, a method of printing on a printing substrate without contact, such as an inkjet printing method, has been considered as a method of applying a pretreatment liquid used together with an aqueous inkjet ink. However, the pretreatment liquid applied by the inkjet printing method needs to have printability from an inkjet head, represented by ejection stability, in addition to the aggregating ability of solid components in the aqueous inkjet ink, the thickening ability of the aqueous inkjet ink, and abrasion resistance. Therefore, the difficulty of formulating the pretreatment liquid applied by the inkjet printing method is very high. In addition, since the aggregating agent is generally a cationic component, it can be said that it is extremely difficult to manufacture a pretreatment liquid containing the aggregating agent and an anionic component (e.g., an anionic resin).

[0005] For example, Patent Document 3 discloses a water-based primer ink (aqueous pretreatment liquid) containing a water-soluble resin having cationic properties as an aggregating agent, and a nonionic thickener (resin having a thickening effect) such as a polyether polyol urethane resin. However, when the present inventors evaluated the pretreatment liquid specifically disclosed in the examples of Patent Document 3, they found that the ejection stability may not be good depending on the type of inkjet head and printing conditions.

[0006] Patent Document 4 discloses a liquid composition for surface treatment (pretreatment liquid) that contains nonionic resin particles and a polyvalent metal salt and specifies the contact angle of water with a film formed on a printing substrate. However, as a result of evaluating the pretreatment liquid specifically disclosed in the examples of Patent Document 4, it was found that the continuous ejection stability may not be good depending on the printing conditions, such as the occurrence of nozzle leakage (a phenomenon in which the aqueous inkjet ink is not ejected from the nozzle) during continuous ejection.

[0007] As described above, it can be said that there has not yet been sufficient research into a pretreatment liquid that is applied in an inkjet printing method and used together with an aqueous inkjet ink, that gives a printed matter with excellent print quality, that has excellent ejection stability at the beginning of printing and continuous ejection stability, and that also has good blending stability during production. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2004-276253 A [Patent Document 2] JP 2011-56884 A [Patent Document 3] JP 2019-143058 A [Patent Document 4] Patent Publication No. 2021-790 Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made to solve the above problems, and an object of the present invention is to provide a pretreatment liquid for use with an aqueous inkjet ink, which can give a printed matter with excellent print quality, has excellent ejection stability at the beginning of printing and continuous ejection stability, and has good blending stability during production. A further object of the present invention is to provide a pretreatment liquid which, in addition to the above-mentioned effects, also has excellent abrasion resistance of the printed matter. Another object of the present invention is to provide an ink set comprising a pretreatment liquid having the above-mentioned effects and an aqueous inkjet ink, which can produce printed matter with excellent print quality even when printing at high speed. [Means for solving the problem]

[0010] As a result of extensive research, the present inventors have found that the above-mentioned problems can be solved by a pretreatment liquid and ink set having the following compositions, and have thus completed the present invention.

[0011] That is, the present invention relates to a pretreatment liquid described in [1] to [5] below, an ink set described in [6] below, and a printed matter produced using the ink set described in [7] below. [1] A pretreatment liquid for use with an aqueous inkjet ink, comprising a flocculant, a resin (excluding cationic resins), a water-soluble organic solvent, and water, The resin contains a nonionic resin (R), the water-soluble organic solvent includes a water-soluble organic solvent (S1) having an octanol / water partition coefficient of −1.60 or more and less than −0.20, and a water-soluble organic solvent (S2) having an octanol / water partition coefficient of −0.20 to 1.00; A pretreatment liquid, wherein, when the content of the nonionic resin (R) contained in 100 g of the pretreatment liquid is WR (g) and the content of the water-soluble organic solvent (S2) is WS2, a value expressed by WR / WS2 is 0.03 to 10. [2] The pretreatment liquid according to [1], wherein a ratio of a mass content of the water-soluble organic solvent (S2) to a total mass content of the water-soluble organic solvent (S1) and the water-soluble organic solvent (S2) is 0.05 to 0.5. [3] The pretreatment liquid according to [1] or [2], wherein the nonionic resin (R) is a water-soluble resin. [4] further comprising a crosslinking agent, The pretreatment liquid according to any one of [1] to [3], wherein the crosslinking agent contains a polyhydrazide compound. [5] The pretreatment liquid according to any one of [1] to [4], which is for use in an inkjet printing method. [6] An ink set comprising the pretreatment liquid according to any one of [1] to [5] and an aqueous inkjet ink containing a pigment, a water-soluble organic solvent, and water. [7] A printed matter obtained by printing the ink set described in [6] on a printing substrate. Effect of the Invention

[0012] According to the present invention, it is possible to provide a pretreatment liquid for use with an aqueous inkjet ink, which can give a printed matter having excellent print quality, has excellent ejection stability at the beginning of printing and continuous ejection stability, and has good blending stability during production. Furthermore, according to the present invention, it is possible to provide a pretreatment liquid for use with an aqueous inkjet ink, which can give a printed matter having excellent print quality, has excellent ejection stability at the beginning of printing and continuous ejection stability, and has good blending stability during production. In addition, according to the present invention, it is possible to provide a pretreatment liquid for use with an aqueous inkjet ink, which can give a printed matter having excellent abrasion resistance in addition to the above-mentioned effects.

[0023] Furthermore, the present invention makes it possible to provide an ink set comprising the above-mentioned pretreatment liquid and an aqueous inkjet ink, which has the above-mentioned effects and is capable of producing printed matter with good print quality, particularly when printing at high speed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, preferred embodiments of the present invention will be described. Note that the present invention is not limited to the following embodiments, and includes various modified examples that are implemented without departing from the gist of the invention.

[0014] In general, when printing an aqueous inkjet ink on a printing substrate with low permeability such as coated paper or film by inkjet printing, the droplets of the aqueous ink that land on the printing substrate mix with each other, resulting in a decrease in the print quality of the resulting printed matter. As a solution to this problem, a method of using a pretreatment liquid containing a flocculant in combination with the aqueous inkjet ink is known. Specifically, the pretreatment liquid is applied to the printing substrate in advance, and the aqueous inkjet ink is printed on a layer (pretreatment layer) formed by the pretreatment liquid. In this way, the flocculant present in the pretreatment layer destroys the dispersion state of the solid components contained in the aqueous inkjet ink and / or rapidly thickens the aqueous inkjet ink. As a result, the droplets of the aqueous inkjet ink are prevented from mixing with each other, and the print quality can be improved.

[0015] When the pretreatment liquid is printed on a printing substrate by an inkjet printing method, if the viscosity of the pretreatment liquid is too low, it falls below the viscosity range that can be discharged from the inkjet head, and the pretreatment liquid cannot be printed on the printing substrate. As a method for imparting viscosity to the pretreatment liquid, a method of adding a resin to the pretreatment liquid can be mentioned. In this case, in order to make the pretreatment liquid dischargeable from the inkjet head, it is necessary to make the resin stable even in the presence of a flocculant. From this viewpoint, it is preferable to use a resin that does not have ionicity (nonionic resin) as the resin. In addition, although the detailed mechanism is unknown, the use of a pretreatment liquid containing a nonionic resin and a flocculant makes it possible to further improve the print quality of the printed matter. Furthermore, the use of a nonionic resin provides good compounding stability during production, even when the pretreatment liquid contains a flocculant.

[0016] On the other hand, nonionic resins have a characteristic that hydrophobic segments associate with each other due to hydrophobic interaction (association force). This association force imparts an appropriate viscosity to the pretreatment liquid containing the nonionic resin, making it possible to eject the liquid from an inkjet head. However, if the association force is too strong, the nonionic resins may aggregate with each other. In addition, if a strong association force acts between nonionic resins, the viscoelasticity of the pretreatment liquid becomes too high, causing problems such as the pretreatment liquid not being ejected at the start of printing or difficulty in continuous ejection. In addition, when the pretreatment liquid is manufactured, the aggregated nonionic resin may appear as precipitation or turbidity.

[0017] Therefore, in the present invention, a water-soluble organic solvent (S2) having an octanol / water partition coefficient of -0.20 to 1.00 is blended in a predetermined amount with respect to the nonionic resin (R). It is presumed that the water-soluble organic solvent (S2), which is relatively highly hydrophobic, acts on the association part of the hydrophobic segment in the nonionic resin (R), thereby appropriately loosening the association part and suppressing an increase in viscoelasticity, thereby improving the initial discharge stability, continuous discharge stability, and blending stability during production. In particular, when the content of the nonionic resin (R) contained in 100 g of the pretreatment liquid is WR (g) and the content of the water-soluble organic solvent (S2) is WS2, by making the value represented by WR / WS2 0.03 or more, the effect of the water-soluble organic solvent (S2) described above is fully expressed, and the initial discharge stability, continuous discharge stability, and blending stability during production are improved. Furthermore, by setting the above ratio to 10 or less, the associated portions are prevented from being excessively loosened by the water-soluble organic solvent (S2), and the pretreatment liquid has suitable viscoelasticity, thereby enabling continuous and stable discharge to be achieved.

[0018] On the other hand, as described above, the water-soluble organic solvent (S2) is highly hydrophobic, and therefore has low affinity with water and hydrophilic materials such as coagulants present in the pretreatment liquid, and may not be uniformly present in the pretreatment liquid. In such cases, the above-mentioned effects are only expressed to a limited extent in the pretreatment liquid, and there is a risk that the initial ejection stability and the continuous ejection stability are not sufficiently improved. In addition, when the water in the pretreatment liquid dries near the nozzle of the inkjet head, the presence ratio of the water-soluble organic solvent (S2) increases, and the hydrophilic material precipitates, which may deteriorate the continuous ejection stability.

[0019] Therefore, in the present invention, a water-soluble organic solvent (S1) having a high affinity with water and an octanol / water partition coefficient of -1.60 or more and less than -0.20 is blended into the pretreatment liquid. This makes it possible to maintain the affinity between the water-soluble organic solvent (S2) and the water and hydrophilic material. As a result, even if a part of the water in the pretreatment liquid evaporates, the hydrophilic material does not precipitate, and the pretreatment liquid can be stably discharged. Furthermore, the favorable affinity of the above-mentioned materials further improves the blending stability when producing the pretreatment liquid.

[0020] In addition, the affinity-improving effect of the water-soluble organic solvent (S1) allows the flocculant, which is a hydrophilic material, to be uniformly present in the pretreatment liquid, which is mainly composed of water. As a result, the action of the flocculant is not exerted unevenly in the pretreatment layer, and it is possible to obtain a printed matter with excellent print quality.

[0021] In addition, when only the water-soluble organic solvent (S1) is used without using the water-soluble organic solvent (S2), the highly hydrophilic water-soluble organic solvent (S1) cannot act on the association part of the hydrophobic segment of the nonionic resin (R), making it difficult to improve the initial discharge stability and the continuous discharge stability. On the other hand, when a water-soluble organic solvent with an octanol / water partition coefficient of more than 1.00 is used, the association part of the hydrophobic segment of the nonionic resin (R) is excessively loosened, making it difficult to ensure the initial discharge stability and the continuous discharge stability, and also deteriorating the blending stability when producing the pretreatment liquid.

[0022]

[0043] As described above, in order to simultaneously and at a high level achieve the print image quality of the printed matter, the initial ejection stability, the continuous ejection stability, and the blending stability during production, a pretreatment liquid that is used together with the aqueous inkjet ink having the configuration of the present invention is indispensable.

[0023] Next, each component constituting the pretreatment liquid used together with the aqueous inkjet ink, which is an embodiment of the present invention (hereinafter also simply referred to as the "pretreatment liquid of this embodiment"), will be described in detail below.

[0024] <Flocculant> The pretreatment liquid of this embodiment contains a flocculant. In order to simultaneously achieve all of continuous discharge stability, print image quality, and blending stability during production, the flocculant preferably contains at least one selected from the group consisting of polyvalent metal salts and cationic resins. As described above, the flocculant can destroy the dispersion state of solid components contained in the aqueous inkjet ink and / or can rapidly thicken the aqueous inkjet ink, thereby improving the print image quality of the resulting printed matter.

[0025] (polyvalent metal salts) When the pretreatment liquid of the present embodiment contains a polyvalent metal salt as an aggregating agent, the combination of the polyvalent metal ion and the counter anion constituting the polyvalent metal salt is not particularly limited, and any combination of conventionally known ions can be used. Among them, a polyvalent metal salt composed of a divalent metal ion is preferably used because it has an excellent balance between the ability to break the dispersion state of solid components in the aqueous inkjet ink and / or the ability to thicken the aqueous inkjet ink, and the wettability and spreadability of the droplets of the aqueous inkjet ink, and can obtain a printed matter with excellent print quality without whiteout and color bleeding regardless of the type of image to be printed, even in high-speed printing. As the divalent metal ion, calcium ion, magnesium ion, zinc (II) ion, iron (II) ion, etc. can be used. Among these, it is particularly preferable to select calcium ion, since it can obtain a printed matter with particularly excellent print quality without whiteout and color bleeding.

[0026] On the other hand, examples of counter anions when calcium ions are selected as polyvalent metal ions include chloride ions (75 g), nitrate ions (121 g), permanganate ions (338 g), formate ions (17 g), acetate ions (28 g), propionate ions (38 g), butyrate ions (17 g), benzoate ions (2 g), lactate ions (9 g), malate ions (0.8 g), gluconate ions (3 g), pantothenate ions (35 g), hydroxide ions (0.1 g), etc. The values ​​in parentheses are the solubility of calcium salt anhydride in 100 g of water at 20°C.

[0027] When an aqueous inkjet ink is printed on a pretreatment layer in a dried state, the rate of redissolution and release into droplets of the aqueous inkjet ink is not too high, improving the print quality of the printed matter, and furthermore, from the viewpoint of obtaining the above-mentioned printed matter having excellent abrasion resistance and adhesion, when the pretreatment liquid of the present embodiment contains a polyvalent metal salt as an aggregating agent, it is preferable to use a polyvalent metal salt having a solubility of 1 to 70 g in 100 g of water at 20° C., more preferably a salt having a solubility of 2 to 55 g, even more preferably a salt having a solubility of 4 to 40 g, and particularly preferably a salt having a solubility of 8 to 25 g. However, the above solubility is the value for the salt anhydride.

[0028] From the above viewpoints, when a polyvalent metal salt is used as a flocculant in the pretreatment solution of this embodiment, one or more selected from the group consisting of calcium formate, calcium acetate, calcium propionate, calcium butyrate, calcium benzoate, calcium lactate, calcium gluconate, and calcium pantothenate can be suitably selected. Only one of these calcium salts may be used, or two or more of them may be used in combination.

[0029] From the viewpoints of improving the print quality of printed matter and further improving the blending stability during production of the pretreatment liquid, the content of the polyvalent metal salt relative to the total amount of the pretreatment liquid is preferably 0.1 to 40 mass%, more preferably 0.3 to 20 mass%, and particularly preferably 0.5 to 10 mass%. However, the content of the polyvalent metal salt refers to the content of anhydride, and when a polyvalent metal salt containing a hydrate is used, the content is calculated excluding the mass of the water of hydration.

[0030] (cationic resin) The pretreatment liquid of this embodiment can use a cationic resin as a flocculant. In this application, the term "cationic resin" refers to a resin having only cationic groups as ionic groups, or a resin having cationic and anionic groups as the ionic groups, and the molar equivalent number of the cationic groups is greater than the molar equivalent number of the anionic groups. Specifically, a resin having a cationic group millimole equivalent greater than 0.4 mmole q. / g and a cationic group millimole equivalent greater than the anionic group millimole equivalent is the "cationic resin" in this application.

[0031] The cationic group millimole equivalent is calculated by multiplying the number of millimoles of cationic groups contained in 1 g of resin by the valence of the cationic groups (however, when the resin contains two or more kinds of cationic groups, the product of the number of millimoles contained in 1 g of resin and the valence calculated for each cationic group is added together). The method for calculating the anionic group millimole equivalent is the same as the above-mentioned method for calculating the cationic group equivalent, except that "cationic group" is replaced with "anionic group".

[0032] Examples of the cationic group include a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium group, an amide group, a pyrrole group, a pyridine group, and an imidazole group. Examples of the anionic group include a carboxy group, a sulfo group, a sulfino group, a phosphate group, and a phosphoryl group.

[0033] The cationic resin may be a water-soluble resin or resin fine particles, which will be described later. A water-soluble cationic resin and resin fine particles, which are cationic resins, may be used in combination.

[0034] When the pretreatment liquid of this embodiment contains a cationic resin as an aggregating agent, it is preferable that the cationic resin is a water-soluble resin, since a printed matter having excellent print image quality and abrasion resistance can be obtained, and further a pretreatment liquid having good blend stability during production can be obtained. The term "water-soluble resin" will be described later.

[0035] In addition, in the pretreatment liquid of the present embodiment, a resin containing a diallylamine structural unit and / or a diallylammonium structural unit can be preferably used because the print quality and abrasion resistance of the printed matter can be compatible. In particular, a resin containing a diallylammonium structural unit is particularly preferably selected because it has an excellent balance between the ability to break the dispersion state of solid components in the aqueous inkjet ink and / or the ability to thicken the aqueous inkjet ink, and the wettability and spreadability of the droplets of the aqueous inkjet ink, and because it easily produces a printed matter without white spots and color bleeding, and because the quaternary ammonium group interacts with the functional group present on the surface of the printing substrate, it produces a printed matter with excellent adhesion. Furthermore, in terms of availability, the hydrochloride or ethyl sulfate of diallyldimethylammonium and / or diallylmethylethylammonium is preferably selected as the diallylammonium structural unit.

[0036] Examples of commercially available cationic resins containing a diallylammonium structural unit include PAS-H-1L, PAS-H-5L, PAS24, PAS-84, PAS-J-81L, PAS-J-81, PAS-J-41, PAS-880, PAS2351, and PAS2451 (manufactured by Nittobo Medical Co., Ltd.); Unisense FPA100L, FPA101L, FPA102L, FPA1000L, FPA1001L, FCA1000L, FCA1001L, CA1002L, FCA1003L, FCA5000L, ZCA1000L, ZCA1001L, and ZCA1002L (manufactured by Senka Co., Ltd.).

[0037] The cationic resin may be used alone or in combination of two or more kinds. From the viewpoint of achieving both good print quality and abrasion resistance of the printed matter, the content of the cationic resin relative to the total amount of the pretreatment liquid is preferably 1 to 30 mass%, more preferably 2 to 20 mass%, and particularly preferably 2.5 to 15 mass%.

[0038] (organic acid) When the pretreatment liquid of the present embodiment contains an organic acid as an aggregating agent, any organic acidic compound having an acid group such as a carboxy group, a sulfo group, a sulfino group, a phosphate group (phosphoric acid group), or a phosphoryl group can be used. Among them, organic acids having a carboxy group or a phosphate group are preferably used from the viewpoint of obtaining a printed matter having excellent print quality. From the same viewpoint, that is, from the viewpoint of improving the print quality of the printed matter, compounds having a plurality of the above-listed acid groups can be preferably used. Specifically, examples of compounds that can be preferably used as organic acids include glutaric acid, malonic acid, succinic acid, malic acid, tartaric acid, citric acid, and pyrophosphoric acid.

[0039] The organic acid may be used alone or in combination of two or more kinds. From the viewpoint of improving the print quality of the printed matter, the content of the organic acid relative to the total amount of the pretreatment liquid is preferably 1 to 30 mass %, and more preferably 3 to 20 mass %.

[0040] <Resins (excluding cationic resins)> The pretreatment liquid of this embodiment contains at least one type of resin other than cationic resin. As described above, the resin must be able to exist stably even in the presence of a flocculant, so a nonionic resin (R) that does not have ionicity is used.

[0041] (Nonionic resin (R)) In the present application, the term "nonionic resin" refers to a resin having an anionic group millimolar equivalent of 0.4 mmole / g or less (or 0 mmole / g) and a cationic group millimolar equivalent of 0.4 mmole / g or less (or 0 mmole / g). If the resin satisfies these requirements, it can be stably present in the pretreatment liquid even in the presence of the coagulant.

[0042] Specific examples of resins that can be used as the nonionic resin (R) include urethane (urea) resins, (meth)acrylic resins, (anhydrous) maleic acid resins, vinyl alcohol resins, polyolefin resins, polyester resins, vinyl chloride resins, etc., but are not limited thereto as long as the resins satisfy the above-mentioned requirements. As the nonionic resin (R), only one type of resin may be used, or two or more types may be used in combination.

[0043] In one embodiment, the nonionic resin (R) preferably has a hydrophobic segment, since it can effectively impart viscosity to the pretreatment liquid and improve the initial discharge stability and continuous discharge stability. In the resin having a hydrophobic segment, the hydrophobic segments associate with each other through hydrophobic interaction. This can impart a viscosity effective for improving the discharge stability to the pretreatment liquid. As described above, if the association force is too strong, the initial discharge stability, continuous discharge stability, etc. may deteriorate, but in the pretreatment liquid of this embodiment, this deterioration can be suppressed by using a water-soluble organic solvent (S2) or the like in combination.

[0044] In this application, "urethane (urea)" means urethane and / or urethane urea, "(meth)acrylic" means acrylic and / or methacrylic, and "(maleic anhydride)" means maleic acid and / or maleic anhydride. In addition, in the present application, the term "(meth)acrylic resin" refers to a resin using one or more polymerizable monomers selected from the group consisting of acrylic acid, methacrylic acid, acrylic acid esters, and methacrylic acid esters. In addition to the polymerizable monomers listed above, a styrene-based monomer may be further used as a polymerizable monomer constituting the acrylic resin. However, a resin containing maleic acid (anhydride) as the polymerizable monomer is not included in the "(meth)acrylic resin" in the present application. Furthermore, the term "maleic anhydride resin" in the present application refers to a resin using at least maleic anhydride as a polymerizable monomer. The maleic anhydride resin may further use one or more polymerizable monomers selected from the group consisting of α-olefins, acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, styrene, and styrene derivatives.

[0045] Generally, water-soluble resins and resin particles are known as the form of resin. Either type of nonionic resin (R) may be used as the nonionic resin (R) contained in the pretreatment liquid of the present embodiment, and both types may be used in combination.

[0046] In this application, a resin having a solubility of 1 g or more in 100 g of water at 25°C is referred to as a "water-soluble resin", a resin having a solubility of less than 1 g is referred to as a "water-insoluble resin", and among the above water-insoluble resins, a resin dispersed in particulate form in water and having a volume-based median diameter (also referred to as "D50" in this application) of 10 to 1,000 nm is referred to as a "resin microparticle". In addition, D50 in this application is a value measured in a 25°C environment using a dynamic light scattering particle size distribution measuring device such as Microtrac-Bell's "Nanotrac UPA-EX150" with water as the dispersion medium.

[0047] In one embodiment, it is preferable to use a water-soluble resin because it can impart a suitable viscosity to the pretreatment liquid and improve the initial discharge stability and continuous discharge stability. In addition, when using a water-soluble resin as the nonionic resin (R), a hydrophobically modified urethane (urea) resin is preferably used because it improves the initial discharge stability and continuous discharge stability even when the blending amount is small, and because the viscosity increases quickly on a non-permeable substrate during printing and drying, improving the print quality of the printed matter.

[0048] In the present application, the term "hydrophobically modified urethane (urea) resin" refers to a urethane (urea) resin having an alkyl group and / or an alkylene group having 6 or more carbon atoms in the molecule. Commercially available examples of the hydrophobically modified urethane (urea) resin include, but are not limited to, the Adekanol UH series (manufactured by ADEKA Corporation) and the SN Thickener 600 series (manufactured by SAN NOPCO LTD.).

[0049] In addition, when the pretreatment liquid of this embodiment contains a water-soluble resin as the nonionic resin (R), by using a resin having dispersion stabilizing ability as the water-soluble resin, it becomes possible to further use, for example, an anionic resin described below. This is because the water-soluble resin having dispersion stabilizing ability functions as a protective colloid for the anionic resin, and can stabilize the anionic resin in the pretreatment liquid even in the presence of a flocculant.

[0050] In the present application, the term "resin having dispersion stabilizing ability" refers to a site that adsorbs to a material to be dispersed (anionic resin in the above-mentioned example), i.e., a resin containing a certain amount of aromatic ring structures. Specifically, the term refers to a resin in which the content of aromatic ring structures represented by the following formula 1 is 10% by mass or more (preferably 15% by mass or more, and particularly preferably 20% by mass or more).

[0051] Formula 1: (Aromatic ring structure content) (mass%) = Σ[(ni × MS ÷ Mi) × Wi]

[0052] In the above formula 1, ni is the number of moles of an aromatic ring structure contained in a polymerizable monomer having an aromatic ring structure among the polymerizable monomers constituting the resin (for example, ni=1 for styrene and ni=2 for phenylstyrene), MS is the molecular weight (78.1) of the target structure (aromatic ring structure), Mi is the molecular weight of the polymerizable monomer having the aromatic ring structure, and Wi is the content (mass%) of the polymerizable monomer having the aromatic ring structure relative to the total amount of polymerizable monomers constituting the resin.

[0053] In addition, when the type and content of the polymerizable monomer constituting the resin are unknown, the content of the polymerizable monomer having an aromatic ring structure and the number of moles of the aromatic ring structure can be measured, for example, by NMR (nuclear magnetic resonance) measurement, and then the content of the aromatic ring structure can be calculated by the above formula 1.

[0054] Examples of water-soluble resins having such dispersion stabilizing ability and being nonionic resins (R) include DISPERBYK-190, 192, 2015, and BYKJET-9151 (manufactured by BYK-Chemie). The blending amount of these resins having dispersion stabilizing ability and being nonionic resins (R) is preferably 5 to 40 mass %, more preferably 10 to 30 mass %, relative to the blending amount of the material to be dispersed (anionic resin in the above-mentioned example).

[0055] When the nonionic resin (R) contains a water-soluble resin, only one type may be used, or two or more types may be used in combination. From the viewpoint of particularly improving the initial discharge stability and continuous discharge stability of the pretreatment liquid, the content of the water-soluble resin as the nonionic resin (R) relative to the total mass of the pretreatment liquid is preferably 0.1 to 10 mass%, and particularly preferably 0.5 to 5 mass%.

[0056] On the other hand, as another embodiment, the pretreatment liquid of the present embodiment may contain resin particles as the nonionic resin (R). By using the resin particles, the scratch resistance of the resulting printed matter can be improved. Any resin that satisfies the above-mentioned anionic group millimole equivalent and anionic group millimole equivalent, as well as the requirements of the resin particles, can be used as the nonionic resin (R). Among them, polyolefin resins are preferably used from the viewpoint of achieving both initial ejection stability and scratch resistance of the printed matter. Examples of commercially available products of the above polyolefin resins include, but are not limited to, the AQUACER series (manufactured by BYK-Chemie), the Hi-Tec E series, and the Hi-Tec P series (manufactured by Toho Chemical Industry Co., Ltd.).

[0057] When resin fine particles are used as the nonionic resin (R), only one type may be used, or two or more types may be used in combination. From the viewpoint of simultaneously achieving both the initial discharge stability and continuous discharge stability of the pretreatment liquid, and the abrasion resistance of the printed matter, the content of the resin fine particles as the nonionic resin (R) relative to the total mass of the pretreatment liquid is preferably 0.1 to 20 mass%, and particularly preferably 1 to 10 mass%.

[0058] The pretreatment liquid of this embodiment can use the above-mentioned water-soluble resin and resin fine particles in combination as the nonionic resin (R). When the water-soluble resin and resin fine particles are used as the nonionic resin (R), the ratio of the mass content of the resin fine particles to the mass content of the water-soluble resin (amount of resin fine particles / amount of water-soluble resin) is preferably 0.1 to 200, and particularly preferably 0.5 to 100. By satisfying the above requirements, the initial ejection stability, continuous ejection stability, and abrasion resistance of the obtained printed matter are all improved.

[0059] (anionic resin) The pretreatment liquid of the present embodiment may further contain a resin having anionic properties (anionic resin). Adding an anionic resin to the pretreatment liquid improves adhesion to the printing substrate and abrasion resistance of the printed matter. In the present application, the anionic resin refers to a resin having the above-mentioned anionic group millimole equivalent greater than 0.4 mmole q. / g and the anionic group millimole equivalent is equal to or greater than the cationic group millimole equivalent.

[0060] On the other hand, since an anionic resin is generally aggregated by the flocculant in the pretreatment liquid, it is difficult to make it coexist stably with the flocculant in the pretreatment liquid. However, by using the anionic resin together with the nonionic resin (R) which has the above-mentioned dispersion stabilizing ability and is a water-soluble resin, the anionic resin can be stably present even in the presence of the flocculant.

[0061] In the pretreatment liquid of this embodiment, the resin species exemplified as the resin usable as the nonionic resin (R) can be used as the anionic resin. From the viewpoint of achieving both the initial discharge stability and continuous discharge stability of the pretreatment liquid, and the abrasion resistance of the printed matter, the content of the anionic resin fine particles relative to the total amount of the pretreatment liquid is preferably 0.1 to 20 mass%, more preferably 0.5 to 15 mass%, and particularly preferably 1 to 10 mass%.

[0062] <Water-soluble organic solvent (S)> The pretreatment liquid of this embodiment contains, as the water-soluble organic solvent, a water-soluble organic solvent (S1) having an octanol / water partition coefficient of -1.60 or more and less than -0.20, and a water-soluble organic solvent (S2) having an octanol / water partition coefficient of -0.20 to 1.00. As the octanol / water partition coefficient in this application, for example, a "ClogP" value obtained using "ChemDraw Professional Ver.16.0" manufactured by PerkinElmer can be used.

[0063] In addition, in the present application, the term "water-soluble organic solvent" refers to an organic compound that has a solubility in water at 25°C of 1% by mass or more and is liquid at 25°C.

[0064] (Water-soluble organic solvent (S1)) The water-soluble organic solvent (S1) contained in the pretreatment liquid of this embodiment may be any compound as long as it is a water-soluble organic solvent having an octanol / water partition coefficient of -1.60 or more and less than -0.20. The pretreatment liquid of this embodiment may contain only one type of compound as the water-soluble organic solvent (S1), or may contain two or more types of compounds in combination.

[0065] The octanol / water partition coefficient of the water-soluble organic solvent (S1) is more preferably -1.40 to -0.30, and particularly preferably -1.20 to -0.40. By setting the octanol / water partition coefficient of the water-soluble organic solvent (S1) within the above range, the affinity of the water-soluble organic solvent (S2) with water and the hydrophilic material can be increased, and a homogeneous pretreatment liquid can be obtained, thereby improving the continuous discharge stability. In addition, the presence of the water-soluble organic solvent (S1) having an octanol / water partition coefficient within the above range can improve the blending stability during the production of the pretreatment liquid and the storage stability of the pretreatment liquid.

[0066] The content of the water-soluble organic solvent (S1) in the pretreatment liquid of this embodiment is preferably 3 to 45 mass% and more preferably 5 to 30 mass% based on the total amount of the pretreatment liquid. In addition, the content of the water-soluble organic solvent (S1) is preferably more than 60 mass% and less than 93 mass%, and particularly preferably more than 65 mass% and less than 91 mass%, based on the total content of the water-soluble organic solvent (S1) and the water-soluble organic solvent (S2). By setting the content of the water-soluble organic solvent (S1) within the above range, the blending stability during the production of the pretreatment liquid and the storage stability of the pretreatment liquid can be improved. In addition, even if water dries near the nozzle, the flocculant will not precipitate, and a good discharge state can be maintained.

[0067] Examples of compounds that can be used as the water-soluble organic solvent (S1) include ethanol (-0.24), 3-methyl-1,5-pentanediol (-0.24), diethylene glycol dimethyl ether (-0.26), propylene glycol monomethyl ether (-0.30), 3-methyl-1,3-butanediol (-0.33), trimethylolpropane (-0.39), N-methyl-2-pyrrolidone (-0.40), 1,2-butanediol (-0.53), 1,5-pentanediol (-0.64), 2-methyl-1,3-propanediol (-0.71), and 2-methyl-1,3-propanediol (-0.72). Examples of the water-soluble organic solvent include, but are not limited to, octanol (-0.64), dipropylene glycol (-0.69), 1,3-butanediol (-0.73), diethylene glycol monomethyl ether (-0.78), triethylene glycol monomethyl ether (-0.96), 2-pyrrolidone (-0.97), propylene glycol (-1.06), 1,4-butanediol (-1.16), diethylene glycol (-1.30), ethylene glycol (-1.37), triethylene glycol (-1.48), and glycerin (-1.54). The numbers in parentheses are the octanol / water partition coefficients of each water-soluble organic solvent.

[0068] (Water-soluble organic solvent (S2)) Any water-soluble organic solvent (S2) may be used as the water-soluble organic solvent in the pretreatment liquid of this embodiment, so long as it has an octanol / water partition coefficient of -0.20 to 1.00. The pretreatment liquid of this embodiment may contain one type of compound as the water-soluble organic solvent (S2), or two or more types of compounds may be used in combination.

[0069] The octanol / water partition coefficient of the water-soluble organic solvent (S2) is more preferably 0.10 to 0.90, and particularly preferably 0.40 to 0.80. When the octanol / water partition coefficient of the water-soluble organic solvent (S2) is within the above range, the association state between the hydrophobic segments of the nonionic resin (R) can be appropriately loosened, and the continuous discharge stability of the pretreatment liquid can be improved.

[0070] As described above, when the content of the nonionic resin (R) contained in 100 g of the pretreatment liquid is WR (g) and the content of the water-soluble organic solvent (S2) is WS2, the value represented by WR / WS2 is preferably 0.03 to 10, and particularly preferably 0.1 to 2. By setting the value represented by WR / WS2 within the above range, the association state between the hydrophobic segments of the nonionic resin (R) can be appropriately loosened, and the continuous discharge stability of the pretreatment liquid and the blending stability during production are improved.

[0071] Furthermore, in the pretreatment liquid of this embodiment, the ratio of the mass content of the water-soluble organic solvent (S2) to the total mass content of the water-soluble organic solvent (S1) and the water-soluble organic solvent (S2) is preferably 0.05 to 0.5. This satisfactorily exhibits both the effect of the water-soluble organic solvent (S1) of improving the affinity of the water-soluble organic solvent (S2) and the like, and the effect of the water-soluble organic solvent (S2) of loosening the nonionic resin (R), thereby simultaneously improving the initial discharge stability, continuous discharge stability, and blending stability during production.

[0072] In addition, the content of the water-soluble organic solvent (S2) in the pretreatment liquid of this embodiment is preferably 0.1 to 15 mass %, more preferably 1 to 10 mass %, based on the total amount of the pretreatment liquid. In addition, the content of the water-soluble organic solvent (S2) is preferably 5 to 50 mass %, more preferably 7 to 40 mass %, and particularly preferably 9 to 35 mass %, based on the sum of the content of the water-soluble organic solvent (S1) and the content of the water-soluble organic solvent (S2). Since the water-soluble organic solvent (S2) is relatively hydrophobic, by setting the content within the above range, it is easy to maintain affinity with hydrophilic materials such as water and aggregating agents, and a uniform pretreatment liquid can be obtained. As a result, the continuous discharge stability is improved.

[0073] Examples of compounds that can be used as the water-soluble organic solvent (S2) include dipropylene glycol monomethyl ether (-0.16), diethylene glycol monoisopropyl ether (-0.08), tripropylene glycol monomethyl ether (-0.03), 2-methyl-2,4-pentanediol (-0.02), 1,2-pentanediol (0.00), ethylene glycol monoallyl ether (0 Examples of the water-soluble organic solvents include, but are not limited to, ethylene glycol monoisopropyl ether (0.03), diethylene glycol ethyl methyl ether (0.13), dipropylene glycol dimethyl ether (0.36), 3-methoxy-3-methyl-1-butanol (0.42), triethylene glycol mono-n-butyl ether (0.49), diethylene glycol diethyl ether (0.52), 1,2-hexanediol (0.53), diethylene glycol monoisobutyl ether (0.54), propylene glycol mono-n-propyl ether (0.62), diethylene glycol mono-n-butyl ether (0.67), and dipropylene glycol mono-n-propyl ether (0.75). The numbers in parentheses are the octanol / water partition coefficients of each water-soluble organic solvent.

[0074] (Other water-soluble organic solvents) The pretreatment liquid of this embodiment may contain water-soluble organic solvents other than the water-soluble organic solvent (S1) and the water-soluble organic solvent (S2) (also referred to as "other water-soluble organic solvents" in the present application). As the other water-soluble organic solvent, only one type of compound may be used, or two or more types of compounds may be used in combination.

[0075] Examples of other water-soluble organic solvents that can be used in the pretreatment liquid of this embodiment include, but are not limited to, diglycerin (-2.96), glycereth-3 (-3.49), glycereth-20 (-5.42), propylene glycol monobutyl ether (1.15), 2-ethyl-1,3-hexanediol (1.26), diethylene glycol mono-n-hexyl ether (1.72), etc. The numbers in parentheses are octanol / water partition coefficients.

[0076] When the pretreatment liquid of this embodiment contains another water-soluble organic solvent, the content thereof is preferably 0.01 to 5% by mass based on the total amount of the pretreatment liquid.

[0077] The total content of the water-soluble organic solvents in the pretreatment liquid of this embodiment is preferably 1 to 50 mass %, more preferably 3 to 40 mass %, and particularly preferably 5 to 30 mass %, relative to the total amount of the pretreatment liquid.

[0078] <Water> The content of water in the pretreatment liquid of this embodiment is preferably 30 to 95 mass %, more preferably 40 to 90 mass %, and even more preferably 50 to 85 mass %, based on the total amount of the pretreatment liquid. Water is an essential material for increasing the mutual solubility of the materials essential to the pretreatment liquid of this embodiment, such as the coagulant, the nonionic resin (R), the water-soluble organic solvent (S1) and the water-soluble organic solvent (S2), and for improving the blending stability during the production of the pretreatment liquid and the storage stability.

[0079] <Other ingredients> The pretreatment liquid of this embodiment may contain, in addition to the materials described above, materials such as a surfactant, a pH adjuster, a crosslinking agent, and a preservative, as necessary.

[0080] (Surfactant) The pretreatment liquid of this embodiment may further contain a surfactant. As the surfactant, an acetylene diol-based surfactant, an acetylene monool-based surfactant, a siloxane-based surfactant, a fluorine-based surfactant, a polyoxyalkylene monoalkyl ether-based surfactant, etc. may be used. These surfactants may be used alone or in combination of two or more.

[0081] Among these, it is preferable to use one or more surfactants selected from the group consisting of acetylene diol-based surfactants and siloxane-based surfactants as the surfactant, because the surface tension of the pretreatment liquid of this embodiment applied to the printing substrate is significantly reduced in a very short time, thereby improving the print image quality of the printed matter, and because a pretreatment liquid with good wetting and spreading properties can be obtained even for printing substrates with a relatively high interfacial free energy, thereby improving the print image quality regardless of the type of printing substrate.

[0082] Examples of commercially available acetylene diol surfactants include Surfynol 61, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 420, 440, 465, 485, 2502, SE, SE-F, Dynol 604, 607 (manufactured by Evonik), Olfine E1004, E1010, E1020, PD-001, PD-002W, PD-004, PD-005, EXP.4001, EXP.4200, EXP.4123, and EXP.4300 (manufactured by Nissin Chemical Industry Co., Ltd.).

[0083] Examples of commercially available siloxane surfactants include BY16-201, FZ-77, FZ-2104, FZ-2110, FZ-2162, F-2123, L-7001, L-7002, SF8427, SF8428, SH3749, SH8400, 8032ADDITIVE, SH3773M (manufactured by Dow Corning Toray Co., Ltd.), TEGO Glide 100, TEGO Glide 410, TEGO Glide 432, TEGO Glide 435, TEGO Glide 440, TEGO Glide 450, TEGO Twin 4000, TEGO Twin 4100, TEGO Wet250, TEGO Wet260, TEGO Wet270, TEGO Wet280 (Evonik), SAG-002, SAG-503A (Nissin Chemical Industry), BYK-331, BYK-333, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-3420, BYK-UV3500, BYK-UV3510 (BYK-Chemie), KF-3 51A, KF-352A, KF-353, KF-354L, KF-355A, KF-6004, KF-6011, KF-6012, KF-6013, KF-6015, KF-6016, KF-6017, KF-6043, KF-615A, KF-640, KF-642, KF-643 (manufactured by Shin-Etsu Chemical Co., Ltd.), and the like.

[0084] (pH adjuster) The pretreatment liquid of the present embodiment may further contain a pH adjuster. By using the pH adjuster, damage to members used in an application device of the pretreatment liquid is suppressed, pH fluctuation over time is suppressed, and the performance of the pretreatment liquid is maintained for a long period of time, and the storage stability and ejection stability are maintained and improved.

[0085] Specifically, when the pretreatment liquid is to be made basic, alkanolamines such as dimethylethanolamine, diethanolamine, triethanolamine, and N-methyldiethanolamine, ammonia water, alkali metal hydroxides such as lithium hydroxide and potassium hydroxide, and alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium hydrogencarbonate, and potassium carbonate can be used. When the pretreatment liquid is to be acidified, hydrochloric acid, sulfuric acid, acetic acid, citric acid, maleic acid, maleic anhydride, succinic acid, tartaric acid, malic acid, boric acid, fumaric acid, malonic acid, ascorbic acid, glutamic acid, and the like can be used. The pH adjuster is not limited to the above materials, and one type may be used alone, or two or more types may be used in combination.

[0086] The amount of the pH adjuster is preferably 0.01 to 5% by mass, more preferably 0.05 to 3% by mass, based on the total amount of the pretreatment liquid. By keeping the amount of the pH adjuster within the above range, the pH will not change due to external stimuli such as dissolution of carbon dioxide in the air, and the effects of the coagulant, nonionic resin (R), water-soluble organic solvent (S1), and water-soluble organic solvent (S2) will not be hindered.

[0087] (Crosslinking agent) The pretreatment liquid of this embodiment may further contain a crosslinking agent. By using a crosslinking agent in the pretreatment liquid, the adhesion between the printing substrate and the pretreatment layer is improved, and the scratch resistance of the printed matter can also be improved, although the detailed mechanism is unclear.

[0088] As the crosslinking agent contained in the pretreatment liquid, a material capable of exerting the above-mentioned effects can be used, for example, a polyhydrazide-based compound, a (poly)carbodiimide-based compound, a polyoxazoline-based compound, etc. The above-mentioned "(poly)carbodiimide-based compound" refers to a carbodiimide-based compound and / or a polycarbodiimide-based compound. Among these, polyhydrazide compounds can be preferably used. Polyhydrazide compounds can improve the scratch resistance of printed matter without adversely affecting the initial discharge stability, continuous discharge stability, and blending stability during production, because they do not require ionic groups for the crosslinking reaction to proceed, and the degree of the crosslinking reaction can be controlled by the amount of water, making it possible to cause the crosslinking reaction to proceed after application onto a printing substrate.

[0089] As polyhydrazide-based compounds, that is, compounds having two or more hydrazine residues in the molecule, specifically, alkylene dihydrazines such as methylene dihydrazine, ethylene dihydrazine, propylene dihydrazine, and butylene dihydrazine; dihydrazide compounds of saturated aliphatic dibasic acids such as oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, and sebacic acid dihydrazide; dihydrazide compounds of unsaturated dibasic acids such as phthalic acid dihydrazide, fumaric acid dihydrazide, and itaconic acid dihydrazide, etc., can be used. Note that, when a polyhydrazide-based compound is used as a crosslinking agent, it is not limited to the above materials, and only one type may be used, or two or more types may be used in combination.

[0090] The blending amount of the crosslinking agent is preferably 0.01 to 5 mass %, more preferably 0.05 to 3 mass %, based on the total amount of the pretreatment liquid. By keeping the blending amount of the crosslinking agent within the above range, it is possible to improve the adhesion to the printing substrate, the abrasion resistance of the printed matter, the initial discharge stability, the continuous discharge stability, and the blending stability during production, without inhibiting the effects of the flocculant and the nonionic resin.

[0091] <Properties of pretreatment liquid> The pretreatment liquid of this embodiment preferably has a viscosity at 25°C of 1 to 30 mPa·s, more preferably 3 to 20 mPa·s, and particularly preferably 5 to 10 mPa·s. A pretreatment liquid that satisfies the above viscosity range can be stably ejected from an inkjet head, and can provide printed matter with excellent print quality and adhesion, as well as good initial ejection stability and continuous ejection stability. The viscosity of the pretreatment liquid can be measured using, for example, an E-type viscometer (TVE25L viscometer manufactured by Toki Sangyo Co., Ltd.).

[0092] The static surface tension of the pretreatment liquid of this embodiment is preferably 20 to 40 mN / m, more preferably 21 to 37 mN / m, and particularly preferably 22 to 35 mN / m, from the viewpoint of imparting suitable wetting and spreading properties on a non-permeable substrate and forming a uniform and even pretreatment layer to obtain a printed matter with excellent print quality. Note that the static surface tension in this application is a value based on the Wilhelmy method (plate method, vertical plate method) in an environment of 25°C, and can be measured, for example, using an automatic surface tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.) and a platinum plate.

[0093] <Method of manufacturing pretreatment liquid> The pretreatment liquid of this embodiment can be produced by, for example, adding materials such as a flocculant, a nonionic resin (R), a water-soluble organic solvent (S1), a water-soluble organic solvent (S2), water, and, if necessary, an anionic resin, a surfactant, a pH adjuster, and a crosslinking agent, stirring and mixing, and then filtering if necessary. However, the method for producing the pretreatment liquid of this embodiment is not limited to the above method. For example, when using an anionic resin that will flocculate in the presence of a flocculant, it is preferable to mix it with a nonionic resin having a dispersion stabilizing ability in advance and then mix it with other materials from the viewpoint of improving the blending stability. In addition, when stirring and mixing, heating may be performed in the range of 35 to 100 ° C. if necessary.

[0094] <Water-based inkjet ink> The pretreatment liquid of this embodiment can be used in the form of an ink set in combination with one or more aqueous inkjet inks. The aqueous inkjet ink preferably contains a pigment, a resin, and water. The aqueous inkjet ink may further contain a water-soluble organic solvent, a surfactant, and the like.

[0095] As the pigment contained in the aqueous inkjet ink used in combination with the pretreatment liquid of this embodiment, from the viewpoint of obtaining printed matter with excellent color development and light fastness and excellent print image quality, the following can be preferably used: blue pigments such as CI Pigment Blue 15:3 and 15:4; red pigments such as CI Pigment Red 122, 150, 166, 185, 202, 209, 266, 269, 282, and CI Pigment Violet 19; yellow pigments such as CI Pigment Yellow 12, 13, 14, 74, 120, 155, 180, 185, and 213; black pigments such as carbon black; and white pigments such as titanium oxide.

[0096] The aqueous inkjet ink used in combination with the pretreatment liquid of this embodiment preferably contains a resin. The resin preferably contains a pigment dispersing resin used to disperse the pigment and / or a binder resin used to bind the ink layer to the pretreatment layer, and more preferably contains at least a binder resin. It is also possible to add a function as a binder resin to the pigment dispersing resin and not substantially blend in a resin that functions only as a binder resin.

[0097] As the pigment dispersion resin and the binder resin, a resin selected from the group consisting of (meth)acrylic resin, urethane (urea) resin, and polyester resin can be suitably used. In addition to these resins, polyolefin resin particles may be used. By using polyolefin resin particles in combination, the abrasion resistance and the adhesion between the ink layer and the pretreatment layer are particularly improved without adversely affecting the print quality of the printed matter.

[0098] In one embodiment, when a resin selected from the group consisting of (meth)acrylic resin, urethane (urea) resin, and polyester resin is used in combination with polyolefin resin fine particles, the amount of polyolefin resin fine particles relative to the amount of resin selected from the group consisting of (meth)acrylic resin, urethane (urea) resin, and polyester resin is preferably 10 to 100% by mass, and more preferably 20 to 80% by mass. By keeping it within the above range, the function of the resin selected from the group consisting of (meth)acrylic resin, urethane (urea) resin, and polyester resin is not hindered, and the print image quality when printed at high speed, the abrasion resistance, and the adhesion between the ink layer and the pretreatment layer are all suitably improved.

[0099] In addition, both the pigment dispersion resin and the binder resin may have an acid group, and in that case, the acid group may be neutralized with a neutralizing agent. In this case, examples of the neutralizing agent preferably used for neutralization include alkanolamines such as dimethylaminoethanol, diethylaminoethanol, diethanolamine, triethanolamine, aminomethylpropanol, and N-methyldiethanolamine; alkylamines such as trimethylamine, triethylamine, and butylamine; heterocyclic amines such as morpholine; ammonia; and hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide.

[0100] When the aqueous inkjet ink used in combination with the pretreatment liquid of this embodiment contains a water-soluble organic solvent, from the viewpoints that a printed matter having excellent print quality even in high-speed printing can be obtained when used in combination with the pretreatment liquid of this embodiment, and the ejection stability of the aqueous inkjet ink is also excellent, the weighted average boiling point of the water-soluble organic solvent contained in the aqueous inkjet ink at 1 atmospheric pressure is preferably 145 to 215° C., more preferably 150 to 200° C., and particularly preferably 155 to 190° C. Furthermore, from the viewpoints that a printed matter having excellent print quality and good abrasion resistance can be obtained when combined with the pretreatment liquid of this embodiment, even in high-speed printing, without color mixing bleeding, is obtained, the amount of the water-soluble organic solvent having a boiling point of 220° C. or more at 1 atmospheric pressure is preferably 5% by mass or less (may be 0% by mass), more preferably 2% by mass or less (may be 0% by mass), and particularly preferably 1% by mass or less (may be 0% by mass).

[0101] From these viewpoints, when the aqueous inkjet ink contains a water-soluble organic solvent, it is preferable from the viewpoint of print quality during high-speed printing to contain a glycol monoalkyl ether solvent (having a boiling point of 100 to 220°C at 1 atmospheric pressure) and / or a dihydric alcohol solvent (having a boiling point of 100 to 220°C at 1 atmospheric pressure). Also, from the viewpoint of print quality during high-speed printing, it is particularly preferable to use a glycol monoalkyl ether solvent (having a boiling point of 100 to 220°C at 1 atmospheric pressure) in combination with a dihydric alcohol solvent (having a boiling point of 100 to 220°C at 1 atmospheric pressure).

[0102] Examples of glycol monoalkyl ether solvents (having a boiling point of 100 to 220° C. at 1 atmospheric pressure) that can be preferably used include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, 2-methoxy-1-butanol, 3-methoxy-1-butanol, and 3-methyl-3-methoxy-1-butanol.

[0103] As the dihydric alcohol solvent (having a boiling point of 100 to 220°C at 1 atmospheric pressure), from the viewpoint of print image quality during high-speed printing, an alkanediol that does not have hydroxyl groups at both ends of the hydrocarbon chain is preferably used, and further, an alkanediol that has a branched alkyl group is particularly preferably used. Examples of alkanediols that do not have hydroxyl groups at both ends of the hydrocarbon chain and do not have a branched alkyl group (provided that the boiling point at 1 atmospheric pressure is 100 to 220°C) include 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, and 1,2-pentanediol. Examples of alkanediols that do not have hydroxyl groups at both ends of the hydrocarbon chain and have a branched alkyl group (provided that the boiling point at 1 atmospheric pressure is 100 to 220°C) include 2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, and 2-methyl-2,4-pentanediol.

[0104] Furthermore, when the aqueous inkjet ink used in combination with the pretreatment liquid of this embodiment contains a surfactant, the amount of the surfactant added is preferably 0.01 to 5 mass %, more preferably 0.05 to 3 mass %, based on the total amount of the aqueous inkjet ink. As the surfactant, the same compounds as those listed above that can be used as surfactants that can be contained in the pretreatment liquid of this embodiment can be used.

[0105] <Manufacturing method of printed matter> Next, the steps of a method for producing a printed matter using the above pretreatment liquid and aqueous inkjet ink will be described.

[0106] When a printed matter is produced using the above-mentioned pretreatment liquid and aqueous inkjet ink, it is preferable to carry out step (1) of printing the pretreatment liquid on a printing substrate and step (2) of printing the aqueous inkjet ink on the surface of the printing substrate obtained in step (1) to which the pretreatment liquid has been applied, in this order. In step (2), the aqueous inkjet ink may be printed on a layer of the pretreatment liquid in a dry state, or may be printed on a layer of the pretreatment liquid in a wet state. Among these, from the viewpoint of obtaining a printed matter having particularly excellent print quality and abrasion resistance even in high-speed printing, it is preferable that the aqueous inkjet ink is printed on the pretreatment liquid in a wet state (i.e., the pretreatment liquid and the aqueous inkjet ink are for a wet-on-wet printing method).

[0107] In the present application, the term "the pretreatment liquid is in a wet state" refers to a state in which the total amount of remaining volatile components contained in the pretreatment liquid on the printing substrate immediately before the droplets of the aqueous inkjet ink land is 50% by mass or more relative to the total amount of volatile components contained in the pretreatment liquid before application to the printing substrate. In addition, the term "the pretreatment liquid and the aqueous inkjet ink are for a wet-on-wet printing method" refers to a state in which the aqueous white ink is printed on the layer of the pretreatment liquid while the pretreatment liquid applied to the printing substrate before the aqueous inkjet ink is in a wet state. In addition, from the viewpoint of obtaining a printed matter having excellent print quality and abrasion resistance, in step (2), the total amount of remaining volatile components contained in the pretreatment liquid on the printing substrate immediately before the droplets of the aqueous inkjet ink land is more preferably 70% by mass or more, and particularly preferably 90% by mass or more, relative to the total amount of volatile components contained in the pretreatment liquid before application to the printing substrate.

[0108] Here, the total remaining amount of volatile components contained in the pretreatment liquid on the printing substrate immediately before the droplets of the aqueous inkjet ink land can be calculated, for example, by the following method.

[0109] (i) First, calculate the mass per unit area (w0 [g / m 2

[0046] ) is measured using a printing substrate on which the thickness of the pretreatment liquid layer has been measured, and step (2) and subsequent steps are not performed, and step (1) (and, if a drying step or the like is performed after step (1) and before step (2) in the actual manufacturing method, that step is performed) is performed to obtain a printed matter on which only a layer of the pretreatment liquid is formed on the printing substrate. Note that the printing substrate used in the actual manufacturing method is used as the printing substrate. The pretreatment liquid is applied under the same conditions as in the actual manufacturing method. The amount of application is the maximum amount applied to the printing substrate in the actual manufacturing method. For example, when the pretreatment liquid is printed on the printing substrate by an inkjet method, if the maximum amount in the actual manufacturing method is a printing rate of 100%, the pretreatment liquid is printed at a printing rate of 100%. On the other hand, for example, when the pretreatment liquid is applied to the printing substrate by roller coating, the pretreatment liquid is applied so that the thickness of the layer of the pretreatment liquid becomes the maximum thickness in the actual manufacturing method. Then, after the printed matter on which only a layer of the pretreatment liquid is formed is produced, the mass of the printed matter is measured and converted into a mass per unit area (w1 [g / m 2 The mass of the printed matter is, for example, the value measured 30 to 60 seconds after the production of the printed matter in the state between '5 seconds before the droplets of the aqueous inkjet ink land' and 'the moment the droplets of the aqueous inkjet ink land'. Alternatively, if a printed matter immediately before the implementation of step (2) in the actual manufacturing method can be collected from the printing device, the printed matter may be collected from the actual manufacturing method, and w1 may be obtained from the printed matter.

[0110] (ii) On the other hand, using the same type of printing substrate and the same application conditions as those used in the measurement of w1 above, only step (1) is carried out (if a drying step or the like is carried out after step (1) and before step (2) in the actual manufacturing method, this step is not carried out), to obtain a printed matter on which only a layer of the pretreatment liquid is formed on the printing substrate. The mass of the printed matter is measured and converted into mass per unit area (w2 [g / m 2 The mass of the printed matter is, for example, the value measured 30 to 60 seconds after the pretreatment liquid is applied onto the printing substrate. Alternatively, if the printed matter can be collected from the printing apparatus immediately after step (1) in the actual manufacturing method, the printed matter may be collected from the actual manufacturing method and w2 may be obtained from the printed matter. Alternatively, the density d [g / mL] of the pretreatment liquid and the volume per unit area of ​​the pretreatment liquid [mL / m 2 ] and the above-mentioned w0 [g / m 2 ], so w2 = w0 [g / m 2 ] + d [g / mL] × (Volume per unit area of ​​pretreatment solution) [mL / m 2 When printing the pretreatment liquid onto the printing substrate using the inkjet method, the volume of the pretreatment liquid per unit area [mL / m 2 The density d of the pretreatment liquid can be measured, for example, using a specific gravity bottle (pycnometer).

[0111] (iii) The value obtained by the calculation formula 100×(w10-w20×Nvp) / [w20×(1-Nvp)] is the total remaining amount (%) of the volatile components contained in the pretreatment liquid on the printing substrate immediately before the droplets of the aqueous inkjet ink land, where w10=w1-w0, w20=w2-w0, and Nvp is the solid content ratio of the pretreatment liquid (solid content mass (g) / pretreatment liquid mass (g)).

[0112] In the measurement of the total remaining amount of volatile components, the mass is measured using a precision balance. The mass per unit area can be calculated by measuring the mass of a test piece cut to a certain size and then dividing the mass by the area of ​​the test piece.

[0113] <Pretreatment liquid printing process (1)> In the step (1), the method of printing the pretreatment liquid of this embodiment onto the printing substrate can be suitably used in an inkjet printing system because the print image quality can be easily adjusted by controlling the amount of the pretreatment liquid applied in accordance with the printing rate of the aqueous inkjet ink printed in the step (2) and the pretreatment liquid application device can be made compact. In other words, the pretreatment liquid of this embodiment is preferably used for the inkjet printing system.

[0114] As the inkjet printing method, a single pass method may be adopted in which the pretreatment liquid or the like is discharged only once onto the printing substrate, or a multi-pass method may be adopted in which the pretreatment liquid or the like is discharged while a short shuttle head is scanned back and forth multiple times in a direction perpendicular to the conveying direction of the printing substrate. Specific examples of the single pass method include a method in which the inkjet head is scanned only once onto the stopped printing substrate (referred to as a "head scanning type single pass method" in this application), and a method in which the printing substrate is passed only once under a fixed inkjet head to print (referred to as a "head fixed type single pass method" in this application). In the method for producing a printed material using the pretreatment liquid of this embodiment, any of the above-mentioned methods may be adopted, but the head fixed type single pass method is preferably used from the viewpoint that it is not necessary to adjust the discharge timing of the pretreatment liquid or the like relative to the scanning of the inkjet head, and the landing position is unlikely to shift, so that a printed material having excellent print quality can be obtained. The design resolution of the inkjet head used in the fixed-head single-pass method is preferably 600 dpi (dots per inch) or more, and more preferably 720 dpi or more, in order to obtain images with excellent quality.

[0115] On the other hand, when a coating method in which the pretreatment liquid is brought into contact with the substrate is selected as a method for applying the pretreatment liquid, a gravure coater, doctor coater, bar coater, blade coater, flexo coater, roll coater, or the like can be used.

[0116] From the viewpoint of obtaining a printed matter having excellent print quality and abrasion resistance, the thickness of the pretreatment layer immediately after application is preferably 1 to 10 μm, more preferably 2 to 8 μm, and particularly preferably 3 to 7 μm.

[0117] <Pretreatment solution drying process> As described above, in step (2), the aqueous inkjet ink may be printed on the pretreatment layer in a dry state or may be printed on the pretreatment layer in a wet state. When a drying step is introduced after step (1) and before step (2), from the viewpoint of preventing excessive drying of the pretreatment liquid, for example, a room temperature air drying method, a visible light drying method, etc. can be preferably used. In addition, after adjusting the energy given to the pretreatment layer, a method used for drying the aqueous inkjet ink, which will be described later, may be used. Furthermore, these drying methods may be used alone or in combination.

[0118] <Water-based inkjet ink printing process (2)> In step (2), the aqueous inkjet ink is preferably printed on the pretreatment liquid in a wet state. In addition, in order to produce a print with excellent print quality, the aqueous inkjet ink is preferably printed so as to overlap at least a part of the area to which the pretreatment liquid has been applied, and more preferably printed so as to overlap only the area to which the pretreatment liquid has been applied.

[0119] In step (2), the same aqueous inkjet ink may be filled into a plurality of inkjet heads, and the aqueous inkjet ink may be printed onto the printing substrate from each of the inkjet heads. The aqueous inkjet ink filled in the inkjet head may be ejected from the inkjet head in a heated state. In this case, the heating temperature of the aqueous inkjet ink in the inkjet head is preferably 30 to 50°C, and more preferably 30 to 45°C. Furthermore, the aqueous inkjet ink may be printed while heating the printing substrate from, for example, the back surface (the surface opposite to the surface on which the droplets of the aqueous inkjet ink land). In this case, the surface on which the aqueous inkjet ink is printed is preferably heated to a temperature of 30 to 55°C, and more preferably heated to a temperature of 35 to 50°C.

[0120] The aqueous inkjet ink may also include a plurality of aqueous inkjet inks (aqueous inkjet ink set). Specifically, the aqueous inkjet ink may include two or more inks selected from the group consisting of cyan ink, magenta ink, yellow ink, black ink, and white ink.

[0121] <Drying process after printing with water-based inkjet ink> After printing with the aqueous inkjet ink, it is preferable to carry out a step of drying the printed substrate to which the pretreatment liquid and the aqueous inkjet ink have been applied. The drying method employed in this step is not particularly limited, and for example, a conventionally known method such as a heat drying method, a hot air drying method, an infrared drying method, a microwave drying method, a drum drying method, or a method that also functions as a high-frequency dielectric drying method can be used. These drying methods may be used alone or in combination, but in order to reduce damage to the non-permeable substrate and dry efficiently, it is preferable to use a hot air drying method and / or an infrared drying method.

[0122] <Printing base material> The printed matter produced by the present invention can be suitably printed on a conventionally known printing substrate, but since a printed matter having excellent adhesion and abrasion resistance can be obtained, it is preferable to use a non-permeable substrate as the printing substrate. In this application, the term "non-permeable substrate" refers to a substrate into which water does not penetrate or is not absorbed. Note that even if a printing substrate has voids inside, a substrate into which water does not penetrate (for example, a substrate whose surface is coated) corresponds to a non-permeable substrate in this application.

[0123] Specific examples of the non-permeable substrate include thermoplastic resin substrates such as polyvinyl chloride sheets, polyethylene terephthalate (PET) films, polypropylene films, polyethylene films, nylon films, and polystyrene films, metal substrates such as aluminum foil, and glass substrates. These printing substrates may have a smooth or uneven surface, and may be transparent, semi-transparent, or opaque. Furthermore, a substrate made by laminating two or more of the above-listed printing substrates may be used, or a peelable adhesive layer or the like may be provided on the opposite side of the printed surface of the pretreatment liquid and the water-based ink. Note that an adhesive layer or the like may be provided on the printed surface after the production of the printed matter. In addition, the shape of the printing substrate may be a roll or a sheet. In addition, from the viewpoint of uniformly printing the pretreatment liquid of this embodiment without unevenness and particularly improving the adhesion of the printed matter, it is also preferable to subject the non-permeable substrates exemplified above to a surface modification method such as a corona treatment or a plasma treatment before applying the pretreatment liquid. EXAMPLES

[0124] The present invention will now be described in more detail with reference to the following examples and comparative examples. In the following description, "parts" and "%" are by weight unless otherwise specified.

[0125] <Production of pretreatment solutions 1 to 70> Each raw material was added to a stainless steel mixing vessel (capacity 300 mL) equipped with a stirrer and a heating mechanism so as to obtain the blending formula shown in each column of Table 1 below. After addition, stirring and mixing were continued for 1 hour at room temperature (25°C), and then the temperature of the contents of the mixing vessel was heated to 50°C and further stirred and mixed for 1 hour. Thereafter, the mixture was cooled to room temperature, filtered through a nylon mesh with a pore size of 100 μm, and further filtered through a membrane filter with a pore size of 1.2 μm to produce pretreatment solutions 1 to 70. The unit of the amount of each raw material added in Table 1 below is "g." Each raw material was added while stirring the mixture of materials already added to the mixing vessel. Furthermore, ion-exchanged water, coagulant, water-soluble organic solvent (S), nonionic resin (R), and other raw materials were added to the mixing vessel in this order. However, if none of these components were included, the relevant component was skipped and the next component was added, and for compositions containing two or more types of raw materials, the order of addition within that component was arbitrary.

[0126] [Table 1]

[0127] [Table 1]

[0128] [Table 1]

[0129] [Table 1]

[0130] Details of the product names and abbreviations listed in Table 1 above are as follows. Note that "Nv." in Table 1 and below refers to the solids concentration (unit: mass%), and "logP" refers to the water / octanol partition coefficient. PAS-H-5L: Cationic resin manufactured by Nittobo Medical Co., Ltd., containing diallyldimethylammonium hydrochloride as a structural unit. PAS-J-81L: Manufactured by Nittobo Medical Co., Ltd. A cationic resin containing diallyldimethylammonium hydrochloride and acrylamide as structural units. 1,2-PD: 1,2-propanediol (logP: -1.06, boiling point at 1 atm: 188°C) 1,2-BD: 1,2-butanediol (logP: -0.53, boiling point at 1 atm: 193°C) EDG: Diethylene glycol monoethyl ether (logP: -0.39, boiling point at 1 atm: 196°C) 3m-1,5-PenD: 3-Methyl-1,5-pentanediol (logP: -0.24, boiling point at 1 atm: 250°C) 2m-2,4-PenD: 2-Methylpentane-2,4-diol (logP: -0.02, boiling point at 1 atm: 198°C) DPDM: Dipropylene glycol dimethyl ether (logP: 0.36, boiling point at 1 atm: 171°C) 1,2-HexD: 1,2-Hexanediol (logP: 0.53, boiling point at 1 atm: 224°C) DPnP: Dipropylene glycol n-propyl ether (logP: 0.75, boiling point at 1 atm: 210°C) PnB: Propylene glycol monobutyl ether (logP: 1.15, boiling point at 1 atm: 170°C) ADEKA NOL UH-540: Hydrophobically modified water-soluble urethane resin manufactured by ADEKA Corporation DISPER BYK-190: Monoalkoxy polyethylene oxide ester of styrene-maleic acid copolymer (water-soluble resin) manufactured by BYK-Chemie Poval 3-80 aqueous solution: Poval 3-80 (polyvinyl alcohol manufactured by Kuraray, saponification degree: 80%) dissolved in ion-exchanged water to a solid content of 15%. Superflex 500M: Polyurethane resin particles manufactured by Daiichi Kogyo Seiyaku Co., Ltd. - Hi-Tech E-5403P: Oxidized polyethylene resin particles manufactured by Toho Chemical Co., Ltd. Vinyblan 278: Polyvinyl chloride resin particles manufactured by Nissin Chemical Industry Co., Ltd. NeoCryl XK-190: (Meth)acrylic resin particles manufactured by DSM Coating Resins Surfynol 440: Acetylene diol surfactant manufactured by Evonik Surfynol 485: Acetylene diol surfactant manufactured by Evonik TEGO Wet 280: Evonik polyether-modified siloxane surfactant ADH: Adipic dihydrazide SDH: Sebacic dihydrazide V-04: Carbodilite V-04 (a polycarbodiimide compound manufactured by Nisshinbo Chemical Co., Ltd., Nv.: 40% by mass)

[0131] <Production of pigment dispersion> (Production of black pigment dispersion) 15 parts of carbon black (Orion Engineered Carbons' "PrinteX85"), 3 parts of styrene-acrylic resin (a random polymer of styrene / acrylic acid / behenyl acrylate = 45 / 30 / 25 (mass ratio) in which all acid groups have been neutralized with dimethylaminoethanol, anionic group millimolar equivalent 4.2 mmole / g, weight average molecular weight 20,000), and 82 parts of water were charged into a mixing vessel equipped with a stirrer and premixed for 1 hour. After that, using Shinmaru Enterprises' "Dyno Mill" (volume 0.6 L) filled with 1,800 g of zirconia beads with a diameter of 0.5 mm, circulation dispersion was performed until the 50% diameter of the carbon black became about 100 nm, producing a black pigment dispersion.

[0132] (Manufacturing cyan pigment dispersions, magenta pigment dispersions, and yellow pigment dispersions) Cyan pigment dispersion liquid, magenta pigment dispersion liquid, and yellow pigment dispersion liquid were produced using the same raw materials and method as for the black pigment dispersion liquid, except that the pigments shown below were used as pigments and circulatory dispersion was carried out until the pigments reached 50% diameter as shown below. Cyan pigment dispersion: LIONOL BLUE 7358G (CI Pigment Blue 15:3) manufactured by Toyo Color Co., Ltd., 50% diameter = 150 nm Magenta pigment dispersion: Toshiki Red 150TR (CI Pigment Red 150) manufactured by Tokyo Color Materials Co., Ltd., 50% diameter = 200 nm Yellow pigment dispersion: LIONOL YELLOW TT1405G (CI Pigment Yellow 14) manufactured by Toyo Color Co., Ltd., 50% diameter = 150 nm

[0133] <Preparation of aqueous solution of binder resin> An aqueous solution of the binder resin 40 (solid content 30%) was produced by the method described in the examples of JP 2020-180178 A, and used as the "aqueous solution of the binder resin."

[0134] <Production of Water-Based Inkjet Inks 1-13> Each raw material was added to a stainless steel mixing vessel (capacity 300 mL) equipped with a stirrer and a heating mechanism so as to obtain the blending formula shown in each column of Table 2 below. After addition, stirring and mixing were continued for 1 hour at room temperature (25°C), and then the contents of the mixing vessel were heated until the temperature reached 50°C, and further stirred and mixed for 1 hour. The mixture was then cooled to room temperature and filtered through a membrane filter with a pore size of 1 μm to produce water-based black inks 1 to 13. In addition, water-based cyan ink, water-based magenta ink, and water-based yellow ink were obtained in the same manner as the water-based black ink, except that a cyan pigment dispersion, a magenta pigment dispersion, and a yellow pigment dispersion were used as the pigment dispersions, respectively. The water-based black ink, water-based cyan ink, water-based magenta ink, and water-based yellow ink with the same numbers were used as a water-based inkjet ink set in the following evaluations. The unit of the amount of each raw material added in Table 2 below is "g." Each raw material was added while stirring the mixture in the mixing vessel. Furthermore, the ion-exchanged water, water-soluble organic solvent, surfactant, aqueous binder resin solution, and pigment dispersion were added to the mixing vessel in this order. However, for components containing two or more types of raw materials, the order of addition within that component was arbitrary.

[0135] [Table 2]

[0136] Details of the product names and abbreviations listed in Table 2 above that are not used in Table 1 above are as follows. Note that "bp" in Table 2 refers to the boiling point (unit: °C) at 1 atmosphere. 2,3-BD: 2,3-butanediol (boiling point at 1 atmosphere: 183°C) 3m-1,3-BD: 3-methyl-1,3-butanediol (boiling point at 1 atmosphere: 203°C) PM: Propylene glycol monomethyl ether (boiling point at 1 atmosphere: 121°C) DEG: Diethylene glycol (boiling point at 1 atmosphere: 244°C) Surfynol 465: Acetylene diol surfactant manufactured by Evonik

[0137] <Creating printed matter> An inkjet ejection device was prepared in which four inkjet heads KJ4B-1200 (design resolution 1200 dpi, nozzle diameter 20 μm) manufactured by Kyocera Corporation were arranged in the conveying direction of the printing substrate, and the inks were filled in the order of water-based black ink, water-based cyan ink, water-based magenta ink, and water-based yellow ink from the inkjet head on the upstream side with respect to the conveying direction of the printing substrate. Next, using a non-wire bar coater 250-OSP-02 manufactured by OSG System Products Co., Ltd., each of the pretreatment liquids manufactured above was applied to a biaxially oriented polypropylene film "OPU-1" (thickness 20 μm) manufactured by Mitsui Chemicals Tohcello Co., Ltd. so that the wet film thickness was 2.0 ± 0.2 μm, and then the film was fixed on the conveyor as it was without a drying process. Thereafter, the conveyor was driven at a constant speed, and when the polypropylene film passed under the installation part of the inkjet head, each of the water-based inkjet inks was ejected under the condition of a drop volume of 2 pL, and an image described later was printed. The printed polypropylene film was then immediately placed in an air oven at 70°C and dried for 3 minutes to produce a print.

[0138] The above-mentioned printed matter was produced using the combination of the pretreatment liquid and the aqueous inkjet ink set shown in the following Table 3. In the above-mentioned method for producing the printed matter, the total amount of remaining volatile components contained in the layer of the pretreatment liquid on the printing substrate at the time of printing with the aqueous inkjet ink was calculated by the above-mentioned method and was 95 to 100 mass %.

[0139] In addition, three types of images were prepared for printing: an image in which 5cm x 20cm solid color patches with a print rate of 100% were arranged adjacent to each other in the order of cyan, magenta, yellow, and black (hereinafter referred to as a "solid patch image"); an image in which a single color gradation in which the print rate changes continuously from 10 to 80% in the long side direction within an area of ​​5cm x 20cm was arranged adjacent to each other in the order of cyan, magenta, yellow, and black (hereinafter referred to as a "gradation image"); and an image in which 20 characters of each color were printed in 6-point MS Mincho font that mixed hiragana and kanji (Japanese syllabary and kanji) (hereinafter referred to as a "character image"). Then, prints were made using each of the above-mentioned pretreatment liquids.

[0140] The conveyor driving speed during the production of the prints was set to three conditions: 25 m / min, 50 m / min, and 75 m / min, and the above-mentioned three types of images were printed under each conveyor driving speed condition.

[0141] [Examples 1 to 74, Comparative Examples 1 to 8] The above three types of printed matter were produced using the combinations of the pretreatment liquid and the aqueous inkjet ink set shown in Table 3. The following evaluations were carried out using these printed matter and the pretreatment liquid itself. The evaluation results were as shown in Table 3. However, for the combinations of Examples 63 to 74, Evaluations 1 to 3, which were the same evaluation conditions as Example 42, were not carried out.

[0142] <Evaluation 1: Evaluation of compounding stability> The occurrence of precipitates, turbidity, etc. during the manufacture of the above-mentioned pretreatment liquid, and for those in which no precipitates, turbidity, etc. occurred, the pretreatment liquid after manufacture was left to stand for two weeks in a thermostatic chamber set at 60°C, and the occurrence of precipitates, turbidity, etc. was then confirmed to evaluate the compounding stability of the pretreatment liquid during cleaning. The evaluation criteria were as follows, with ◎ and ○ being considered as usable. ◎: No precipitate or turbidity was observed during the preparation of the pretreatment liquid before filtering through a nylon mesh. In addition, even after the pretreatment liquid was filtered through a membrane filter and left to stand for two weeks in a thermostatic chamber set at 60°C, no precipitate or turbidity was observed. ○: When the pretreatment liquid was produced, precipitates and turbidity were observed in the pretreatment liquid before filtering through a nylon mesh, but the precipitates and turbidity could be removed by filtering through the nylon mesh and membrane filter. Furthermore, even when the pretreatment liquid after filtering was left to stand for 2 weeks in a thermostatic chamber set at 60°C, no precipitates or turbidity were observed. ×: When the pretreatment liquid was produced, precipitates or turbidity were observed in the pretreatment liquid before filtering through a nylon mesh. The precipitates or turbidity could not be removed by filtering through a nylon mesh or a membrane filter, or the precipitates or turbidity could be removed by filtering, but when the pretreatment liquid after filtering was left to stand for 2 weeks in a thermostatic chamber set at 60°C, precipitates or turbidity reoccurred.

[0143] <Evaluation 2: Evaluation of initial ejection properties> In order to provide visibility, a cationic dye (Rhodamine B manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was mixed in advance into each pretreatment liquid at a ratio of 0.5% by mass based on the total mass of the pretreatment liquid. Next, the pretreatment liquid to which the dye was added was filled into an inkjet ejection device equipped with a Kyocera inkjet head "KJ4B-1200" (design resolution 1,200 dpi, nozzle diameter 20 μm), and the pretreatment liquid in the inkjet head was pressurized until the pretreatment liquid oozed from the nozzle of the inkjet head. Thereafter, the pretreatment liquid attached to the nozzle plate was wiped off and immediately thereafter a nozzle check pattern was printed under a frequency condition of 40 kHz. The initial ejection property was evaluated by visually counting the number of nozzles missing in the nozzle check pattern. The evaluation criteria were as follows, with ◎, ○, and △ being practically usable. However, for the pretreatment liquids that were rated as "X" in the above evaluation of blend stability, the evaluation of initial dischargeability was not carried out. ◎: No nozzle missing at all ○: The number of missing nozzles was 1 to 4 △: The number of missing nozzles was 5 to 9. ×: The number of missing nozzles was 10 or more.

[0144] <Evaluation 3: Evaluation of continuous ejection> After printing the nozzle check pattern in the above evaluation 2, 10 sheets of solid images (printing rate 100%) with a printing width of 10 cm and a length of 30 cm were printed in succession. After that, the nozzle check pattern was printed again, and the number of nozzles that had dropped out from the number of nozzles that had dropped out in the initial ejection property evaluation was visually counted to evaluate the continuous ejection property. The evaluation criteria were as follows, with ◎, ○, and △ being considered as usable. However, the evaluation of continuous ejection property was carried out only for the pretreatment liquids that were determined to be practically usable in the above-mentioned evaluation of blend stability and evaluation of initial ejection property. ◎: The number of nozzle clogged nozzles was the same as the number of nozzle clogged nozzles in the initial ejection performance evaluation. ○: The number of nozzle missing increased by 1 to 4 from the number of nozzle missing in the initial discharge performance evaluation. △: The number of missing nozzles increased by 5 to 9 from the number of missing nozzles in the initial ejection performance evaluation. ×: The number of nozzle missing increased by 10 or more from the number of nozzle missing in the initial discharge performance evaluation.

[0145] <Evaluation 4: Evaluation of print quality (white areas, dot shape)> Based on the above method, the solid patch image prints produced by changing the conveyor drive speed were visually observed to confirm the degree of whiteout. In addition, the dot shapes in the portion of the print rate of 10 to 20% of the gradation image prints produced by changing the conveyor drive speed were observed at 200 times magnification using an optical microscope. Furthermore, for the character image prints produced by changing the conveyor drive speed, whether all the characters were legible was visually confirmed from the ink layer side (printed surface side). Then, the print quality was comprehensively judged based on the degree of whiteout, dot shape, and character legibility. The evaluation criteria were as follows, and the evaluations of ◎, ○, and △ were considered to be usable. Table 3 shows the results of the color with the worst evaluation among the four colors evaluated. ◎: The printout was printed at a conveyor speed of 75 m / min, and no blank spots, irregular dot shapes, or illegible characters were observed in any of the colors. ○: In the prints printed at a conveyor speed of 75 m / min, there were colors in which one or more of the following was confirmed: whiteout, irregular dot shape, and illegible characters. In the prints printed at a conveyor speed of 50 m / min, none of the following was confirmed: whiteout, irregular dot shape, and illegible characters. △: In prints printed at a conveyor speed of 50 m / min, there were colors in which one or more of the following was confirmed: whiteouts, irregular dot shapes, and illegible characters. In prints printed at a conveyor speed of 25 m / min, none of the following was confirmed: whiteouts, irregular dot shapes, and illegible characters. ×: In prints printed at a conveyor drive speed of 25 m / min, there were colors in which one or more of the following was confirmed: white spots, irregular dot shapes, and illegible characters.

[0146] <Evaluation 5: Evaluation of abrasion resistance> Based on the above method, a print of a solid patch image was prepared at a conveyor driving speed of 50 m / min, and then a test piece of 2 cm x 20 cm was cut out from the obtained print for each color and set in a Gakushin-type friction fastness tester AB-301 manufactured by Tester Sangyo Co., Ltd. Next, a test attachment white cotton cloth (Kanakin No. 3) was attached to a friction element (weight 200 g), and the friction element was subjected to a predetermined number of vibrations while changing the load applied thereto. After the vibration, the state of the surface of the print and the degree of coloring of the cotton cloth were visually confirmed to evaluate the abrasion resistance. The evaluation criteria were as follows, with ◎, ○, and △ being practically usable, and ◎ and ○ being particularly suitable for use. Table 3 shows the results of the color with the worst evaluation among the four colors evaluated. ◎: Even after placing a 300g weight on the friction element (load 500g) and shaking it 50 times, there were no scratches on the printed surface and no coloring was observed on the cotton cloth. ○: After placing a 300g weight on the friction element (load 500g) and shaking it 25 times, there were no scratches on the printed surface and no discoloration of the cotton cloth was observed, but after shaking it 50 times under the same load conditions, scratches on the printed surface and / or discoloration of the cotton cloth were observed. △: After shaking the abrasive 25 times without placing a weight on the abrasive (load 200 g), there were no scratches on the printed surface and no discoloration of the cotton cloth was observed. However, after shaking the abrasive 25 times with a 300 g weight placed on the abrasive (total weight 500 g), scratches on the printed surface and / or discoloration of the cotton cloth were observed. ×: After shaking the abrasive 25 times without placing a weight on the abrasive (load 200 g), scratches were observed on the printed surface and / or coloring was observed on the cotton cloth.

[0147] [Table 3]

[0148] [Table 3]

[0149] [Table 3]

[0150] As is clear from Table 3, it was confirmed that the combinations using pretreatment liquids 1 to 62 that satisfy the above-mentioned requirements have practical usable quality in all evaluation items, including blending stability during production, initial discharge stability, continuous discharge stability, and print image quality of printed matter. Furthermore, it was confirmed that when a certain amount or more of nonionic resin (R) and / or anionic resin, which are resin fine particles, is contained, or when a crosslinking agent is contained, the scratch resistance of the printed matter is also particularly suitable for use.

[0151] In contrast, in the pretreatment liquid 63 not containing a flocculant, the pretreatment liquid 64 not containing the water-soluble organic solvent S1, the pretreatment liquids 65 and 66 not containing the water-soluble organic solvent S2, the pretreatment liquids 69 and 70 not containing the nonionic resin (R), the pretreatment liquid 67 in which the value represented by the above WR / WS2 is less than 0.03, and the pretreatment liquid 68 in which the value represented by the above WR / WS2 is greater than 10, one or more of the evaluated items did not reach a practically usable level. This result shows that if even one of the above requirements is missing, the above-mentioned effects cannot be achieved.

Claims

1. A pretreatment liquid for use with an aqueous inkjet ink, the pretreatment liquid comprising a flocculant, a resin (excluding cationic resins), a water-soluble organic solvent, and water, The resin contains a nonionic resin (R), The nonionic resin (R) contains a hydrophobically modified urethane (urea) resin which is a water-soluble resin, the water-soluble organic solvent comprises a water-soluble organic solvent (S1) having an octanol / water partition coefficient of −1.60 or more and less than −0.20, and a water-soluble organic solvent (S2) having an octanol / water partition coefficient of −0.20 to 1.00; The pretreatment liquid has a value expressed by WR / WS2 of 0.03 to 10, where WR (g) is the content of the nonionic resin (R) contained in 100 g of the pretreatment liquid and WS2 is the content of the water-soluble organic solvent (S2).

2. 2. The pretreatment liquid according to claim 1, wherein a ratio of a mass content of the water-soluble organic solvent (S2) to a total amount of a mass content of the water-soluble organic solvent (S1) and a mass content of the water-soluble organic solvent (S2) is 0.05 to 0.

5.

3. Further comprising a crosslinking agent, The pretreatment liquid according to claim 1 , wherein the crosslinking agent comprises a polyhydrazide compound.

4. The pretreatment liquid according to claim 1 or 2, which is used in an inkjet printing method.

5. 3. An ink set comprising the pretreatment liquid according to claim 1 or 2, and an aqueous inkjet ink comprising a pigment, a water-soluble organic solvent, and water.

6. A printed matter obtained by printing the ink set according to claim 5 on a printing substrate.

Images