Separation methods

Abstract

To provide pretreatment liquid for use in formation of both printed matters of a paper substrate and a plastic substrate, wherein each of the printed matters is excellent in practical characteristics such as image quality and blocking resistance, and wherein the pretreatment liquid is excellent in separability in separation treatment performed under basic solution and furthermore is excellent in storage stability.SOLUTION: Pretreatment liquid is provided, including: resin particles (A1) each having an SP value of 9.0-14.0(cal / cm3)1 / 2 and an acid value of 1-60 mgKOH / g; calcium ions; carboxylic acid ions; water-soluble organic solvent and / or a surface active agent; and water, wherein a (mixed) SP value of the water-soluble organic solvent and / or the surface active agent is 8.0-14.0(cal / cm3)1 / 2, and a ratio of the amount of the resin particles (A) included in 100 g of the pretreatment liquid to a mmol amount of the calcium ions included in 100 g of the pretreatment liquid is regulated.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a pretreatment solution, an ink set containing the pretreatment solution and an aqueous inkjet ink, a printed material manufactured using the ink set, and a method for separating a layer formed from the aqueous inkjet ink from the printed material. [Background technology]

[0002] In recent years, efforts have been made to recycle substrates from printed materials from an environmental protection perspective. One example is the production of recycled paper from waste printing paper (printed materials printed on paper substrates). Specifically, ink and other substances are removed from the waste printing paper to produce deinked pulp, which is then processed through bleaching, papermaking, and other processes to produce recycled paper (see Patent Documents 1 and 2). Furthermore, with the aim of reducing plastic waste, which is a cause of environmental pollution, research is also underway to remove ink and other substances from printed materials on plastic substrates and reuse them, or to produce recycled pellets from the plastic substrates after removal, and then mold and process them into recycled plastic products (see Patent Documents 3 and 4).

[0003] However, the materials used in Patent Documents 1 to 4 are all printed materials produced by plate-based printing methods such as offset printing and gravure printing. Plate-based printing methods have characteristics such as requiring the creation of printing plates and generating a large amount of spare printed materials and ink loss. In recent years, from the perspective of resource conservation and environmental protection, the demand for digital printing methods, which do not require plates, has been expanding. Although some studies have been conducted on the recycling of substrates from printed materials produced by digital printing methods, it is still far from sufficient.

[0004] Incidentally, one type of digital printing method is the inkjet printing method, which produces printed materials with characters and images formed by ejecting and adhering ink droplets onto a substrate from fine nozzles. Inkjet printing has features such as the ability to miniaturize printing equipment, ease of colorization, and image quality that is less affected by the printing environment, and its use is progressing not only in office and home use but also in industrial use. Furthermore, while solvent inks and UV-curing inks have traditionally been used in inkjet printing for industrial applications, there is a growing demand for water-based inks, which contain water as the main component, from the perspectives of safety and health for printing personnel, as well as environmental protection.

[0005] Furthermore, in recent years, pretreatment solutions have been used to improve image quality in printed materials on low-permeability substrates such as coated paper, art paper, and lightly coated paper, as well as on non-permeable substrates such as plastic substrates. These solutions intentionally induce aggregation of solid components (pigments and / or resins) present in the water-based inkjet ink, or increase the viscosity of the water-based inkjet ink. Adding various resins to the pretreatment solution also improves the properties of the printed material, such as preventing blocking (a phenomenon in which some of the water-based inkjet ink is taken by the substrate when peeling off a substrate that has adhered to the printed surface) and improving substrate adhesion (see, for example, Patent Documents 5 and 6).

[0006] On the other hand, studies on recycling printed materials produced using water-based inks (hereinafter also referred to as "water-based inkjet inks") and pretreatment solutions used in inkjet printing methods, particularly studies focusing on the composition of the water-based inkjet inks and / or pretreatment solutions, have not been conducted extensively to date. These compositions significantly affect the separation characteristics of the layer formed from the water-based inkjet ink on the substrate, and these separation characteristics can influence the quality of recycled paper, recycled plastic substrates, recycled plastic products, etc. (in this application, these substrates are collectively referred to as "recycled substrates, etc."). Therefore, it can be said that studying the composition of the water-based inkjet inks and / or pretreatment solutions used in the printed materials that serve as raw materials is extremely important when manufacturing recycled substrates, etc.

[0007] In this application, the "layer formed from water-based inkjet ink" is also referred to simply as the "water-based inkjet ink layer" or the "water-based inkjet ink layer."

[0008] As one of the few examples of such studies, Patent Document 7 discloses an aqueous inkjet ink containing ferromagnetic particles as a pigment, and a method for producing deinked pulp using printed materials made with the aqueous inkjet ink as raw materials. Patent Document 7 also states that since the ferromagnetic particles can be recovered using magnets or the like, deinked pulp with high whiteness can be produced at low cost and in a simple manner from printed materials made with the above aqueous inkjet ink. However, since ferromagnetic particles are used, these aqueous inkjet inks have the problem that the types and amounts of other materials that can be added are limited, making it difficult to improve and achieve both image quality, color reproduction, and other properties (blocking resistance, substrate adhesion, etc.) of the printed materials.

[0009] Furthermore, in the example described in Patent Document 8, a first liquid composition (pretreatment solution) containing calcium lactate, (meth)acrylic resin particles, propylene glycol (1,2-propanediol), glycerin, acetylenediol-based surfactant, crosslinking agent, etc., and a second liquid composition (aqueous inkjet ink) containing a pigment dispersion, (meth)acrylic resin particles, propylene glycol, glycerin, acetylenediol-based surfactant, etc., are used to produce printed materials on high-quality paper, and a deinking process (production of deinked pulp) is carried out using the printed materials. However, the first liquid composition having the above configuration has poor storage stability, and the resulting printed materials may have poor image quality (details will also be explained in the Examples section), thus posing a challenge to its practicality.

[0010] Furthermore, while Patent Documents 7 and 8 disclose the separation of a layer formed from aqueous inkjet ink from a printed material on a paper substrate, they do not mention at all the separation of a printed material from a plastic substrate.

[0011] As described above, further research is needed to obtain printed materials that exhibit excellent separation characteristics (particularly in separation processes performed under basic solutions) of layers formed from aqueous inkjet inks on both paper and plastic substrates, as well as excellent practical characteristics such as image quality and blocking properties. [Prior art documents] [Patent Documents]

[0012] [Patent Document 1] Japanese Patent Publication No. 2002-69876 [Patent Document 2] Japanese Patent Publication No. 2005-314832 [Patent Document 3] Japanese Patent Application Publication No. 11-209677 [Patent Document 4] Japanese Patent Publication No. 2000-313833 [Patent Document 5] Japanese Patent Publication No. 2020-75954 [Patent Document 6] Japanese Patent Publication No. 2020-75436 [Patent Document 7] Japanese Patent Publication No. 2012-121994 [Patent Document 8] Japanese Patent Publication No. 2021-112900 [Disclosure of the Invention] [Problems that the invention aims to solve]

[0013] The present invention was made to solve the above-mentioned problems, and its objective is to provide a pretreatment solution that exhibits excellent separation properties in separation processes performed under a basic solution for both paper and plastic substrates, as well as excellent practical characteristics of the printed material such as image quality and blocking resistance, and furthermore, good storage stability. [Means for solving the problem]

[0014] As a result of diligent research conducted by the present inventors to achieve the above objective, they discovered a pretreatment solution comprising resin particles (A) having a specific SP value and acid value, calcium ions, carboxylate ions, and a water-soluble organic solvent and / or surfactant having a specific (mixed) SP value, wherein the ratio of the amount of resin particles (A) to the millimolar amount of calcium ions is defined, and thus completed the present invention.

[0015] In other words, the present invention relates to the following [1] to

[10] . [1] A pretreatment solution used in conjunction with an aqueous inkjet ink containing a pigment, resin, and water, for forming a basic-soluble pretreatment layer on a substrate, The aforementioned pretreatment solution comprises resin particles (A), calcium ions, carboxylate ions, a water-soluble organic solvent and / or surfactant, and water. The aforementioned resin particles (A) have an SP value of 9.0 to 14.0 (cal / cm³). 3 ) 1 / 2 It also contains resin particles (A1) with an acid value of 1 to 60 mg KOH / g, The (mixed) SP value of the aforementioned water-soluble organic solvent and / or surfactant is 8.0 to 14.0 (cal / cm³). 3 ) 1 / 2 And, A pretreatment solution in which, when R (g) is the amount of resin particles (A) contained in 100g of the pretreatment solution and C (mmol) is the amount of calcium ions contained in 100g of the pretreatment solution, the ratio of the value of R to the value of C (R / C) is 0.11 to 0.65. [2] The pretreatment solution according to [1], wherein the carboxylate ion comprises two or more types of carboxylate ions. [3] The pretreatment solution according to [1] or [2], wherein the carboxylic acid ion comprises a hydroxycarboxylic acid. [4] The pretreatment solution according to any one of [1] to [3], wherein the ratio of the value of R to the value of C (R / C) is 0.11 to 0.50. [5] The pretreatment liquid according to any one of [1] to [4], wherein the resin particles (A1) are resin particles selected from the group consisting of (meth)acrylic resin particles, urethane (urea) resin particles, urethane (urea)-(meth)acrylic resin particles, and polyester resin particles. [6] The pretreatment solution according to [5], wherein the resin particles (A1) are (meth)acrylic resin particles having a glass transition temperature (Tg) of -10 to 75°C. [7] The pretreatment solution according to any one of [1] to [6], wherein the absolute value of the difference between the SP value of the resin particles (A) and the (mixed) SP value of the water-soluble organic solvent and / or surfactant is 0 to 4.5. An ink set comprising a pretreatment solution described in any of [8][1] to [7], and an aqueous inkjet ink containing a pigment, a resin, and water. [9] A printed article having, in this order, a substrate, a base-soluble pretreatment layer formed using any of the pretreatment solutions described in [1] to [7], and a layer formed from a pigment, a resin, and an aqueous inkjet ink containing water. A method for separating a layer formed from aqueous inkjet ink from a printed material, comprising the step of immersing the printed material described in

[10] [9] in a basic solution. [Effects of the Invention]

[0016] The present invention provides a pretreatment solution that exhibits excellent separation properties in separation processes performed under a basic solution for both paper and plastic substrates, as well as excellent practical characteristics of the printed material such as image quality and blocking resistance, and furthermore, good storage stability. [Modes for carrying out the invention]

[0017] Preferred embodiments of the present invention will be described in detail below. The embodiments described below are examples of the present invention, and the present invention is not limited to the above embodiments. Furthermore, the present invention includes various modifications that do not depart from the spirit of the invention.

[0018] As described above, a pretreatment solution is used to intentionally induce aggregation of solid components present in water-based inkjet inks and / or thickening of the water-based inkjet ink, with the aim of improving the image quality of printed materials on low-permeability or non-permeability substrates. Such aggregation and / or thickening is caused by the release and diffusion of components present in the pretreatment solution that aggregate the solid components contained in the water-based inkjet ink and / or thicken the water-based inkjet ink (hereinafter also referred to as "aggregation / thickening components") into droplets of water-based inkjet ink that have landed on a layer of the pretreatment solution. As a result of this aggregation and / or thickening, color bleeding and color unevenness (unevenness of the color in areas of the same color) of the water-based inkjet ink are suppressed, and image quality is improved.

[0019] In this application, the layer formed by the pretreatment solution is referred to as the "pretreatment solution layer" or "pretreatment layer." Furthermore, the "pretreatment solution layer" ("pretreatment layer") includes both a layer in a wet state (for example, the state immediately after applying the pretreatment solution to the substrate) and a layer in a dry state (for example, the state after applying the pretreatment solution to the substrate and then drying it).

[0020] However, the use of a pretreatment solution containing coagulation / thickening components may result in insufficient solid coverage (no white spots, and solid areas being completely filled with ink) in the resulting printed material. To improve solid coverage on the substrate, it is necessary to allow the water-based inkjet ink droplets to spread sufficiently before the water-based inkjet ink lands and the aforementioned coagulation and / or thickening occurs. In other words, in printed materials using water-based inkjet ink in combination with a pretreatment solution, it is important to simultaneously control the release and diffusion rate of the coagulation components and the wetting rate of the water-based inkjet ink droplets in order to achieve both suppression of color bleeding and unevenness and solid coverage.

[0021] On the other hand, adding resin to the above-mentioned pretreatment solution can significantly improve the blocking resistance and substrate adhesion of printed materials. This effect is thought to be due to intermolecular interactions (inter-ionic interactions, hydrogen bonds, van der Waals forces, etc.) that occur between the resin and the solid components contained in the substrate and / or aqueous inkjet ink.

[0022] In particular, when the above-mentioned resin contains acidic groups such as carboxyl(carboxylic acid) groups, sulfonic acid(sulfo) groups, and phosphonic acid groups, strong intermolecular interactions such as interionic interactions and hydrogen bonds are formed, which allows for a significant improvement in blocking resistance and substrate adhesion. Furthermore, since the resin containing acidic groups (or the pretreatment solution layer containing it) dissolves in a basic solution, the substrate and the aqueous inkjet ink layer formed on top of the pretreatment solution layer can be separated by mixing the printed material having the pretreatment solution layer with a basic solution.

[0023] However, when using a resin containing acidic groups in combination with an agglomerating / thickening component in order to achieve both image quality (such as color bleeding, uneven coloring, and solid fill) and print material characteristics (such as blocking resistance and separation in basic solutions), the agglomerating / thickening component may become trapped in the resin and less likely to be released into the water-based inkjet ink. As a result, the aforementioned agglomerating and / or thickening effects may not manifest, making it even more difficult to achieve both color bleeding, uneven coloring, and solid fill. Furthermore, there is a risk that the acidic groups and the agglomerating / thickening component may interact, forming insoluble salts. In this case, the storage stability of the pretreatment solution cannot be obtained, and both the acidic groups in the resin that contribute to blocking resistance and separation, and the agglomerating / thickening component, are lost. This makes it easier for problems such as deterioration of blocking resistance and separation, as well as color bleeding and uneven coloring, to occur.

[0024] Thus, in order to use a resin containing acidic groups and a flocculating / thickening component in combination and to simultaneously and favorably exhibit the effects of both, it is important to improve the storage stability of the pretreatment solution in which both coexist and to control the interaction between the acidic groups in the resin and the flocculating / thickening component.

[0025] Therefore, in order to solve the above problems, the inventors diligently continued their research and found a pretreatment solution containing resin particles (A) having a specific SP value and acid value, calcium ions, carboxylate ions, and a water-soluble organic solvent and / or surfactant having a specific (mixed) SP value, wherein the ratio of the amount of resin particles (A) to the millimolar amount of calcium ions is defined. Although the details of the mechanism by which the above-described pretreatment solution can suitably solve the above problems and further improve the effect are unknown, the inventors speculate as follows.

[0026] First, a preferred embodiment of the present invention, the pretreatment solution (hereinafter also simply referred to as "the pretreatment solution of the present invention"), contains calcium ions and carboxylate ions. Here, calcium ions function as a flocculating / thickening component, while salts composed of carboxylate ions and calcium ions (calcium carboxylate salts) are known to have low solubility in water. However, calcium carboxylate salts have an appropriate release rate into droplets of aqueous inkjet ink, and calcium ions have a suitable diffusion rate within the droplets of aqueous inkjet ink. Therefore, even when aqueous inkjet ink is printed after the pretreatment solution on the substrate has dried, for example, the release and diffusion rates can be controlled within a suitable range, making it possible to achieve both color bleeding, color unevenness, and solid filling. Note that one type of carboxylate ion may be used alone, or two or more types may be used in combination, but it is desirable to use multiple carboxylate ions. This is because using multiple carboxylate ions allows each calcium carboxylate to exhibit water solubility greater than that of calcium carboxylate alone, thereby achieving further improvement in image quality. Furthermore, the improvement in water solubility achieved by using calcium carboxylate in combination is thought to be due to an effect similar to that of heterogeneous ions.

[0027] Furthermore, the pretreatment solution of the present invention contains resin particles (A). Generally, there are two forms of water-based resins: water-soluble resins and resin particles, and they are used appropriately depending on the properties required for the pretreatment solution and the printed material. In the case of the pretreatment solution of the present invention, resin particles are used to improve the mixing stability with calcium ions, which will be described later, and to improve the blocking resistance. Resin particles are also a suitable material because their viscosity does not increase easily even when added in large quantities, and they easily improve not only the blocking resistance of the printed material but also its abrasion resistance and water resistance.

[0028] In particular, in order to achieve high levels of both blocking resistance in printed materials and separation performance in the layer separation treatment of aqueous inkjet inks performed under a basic solution, resin particles having a certain amount of acid groups are necessary. From this viewpoint, the pretreatment solution of the present invention uses resin particles (A1) with an acid value of 1 to 60 mgKOH / g as resin particles (A). By setting the acid value of resin particles (A1) to 1 to 60 mgKOH / g, it becomes possible to achieve both blocking resistance and separation performance regardless of the composition of the aqueous inkjet ink used in combination or the printing conditions. However, as mentioned above, when a resin containing acidic groups is mixed with calcium ions, which are flocculating / thickening components, interactions occur between the resin and the calcium ions, which not only prevents the aforementioned effects from being obtained but also significantly worsens the storage stability of the pretreatment solution.

[0029] Therefore, the pretreatment solution of the present invention incorporates carboxylate ions, defines the SP value of the resin particles (A1), and further uses a water-soluble organic solvent and / or surfactant having a similar SP value to solve the above-mentioned problems. Although the detailed factors are unknown, it is thought that the hydrogen bonds formed between the acid groups in the resin particles (A1) and the carboxylate ions, as well as the high affinity between materials with similar SP values, cause the carboxylate ions and the water-soluble organic solvent and / or surfactant to be positioned in a way that protects the resin particles (A1), thereby suppressing the approach of calcium ions.

[0030] Furthermore, since the SP values ​​of the resin particles (A1) and the water-soluble organic solvent and / or surfactant are similar, it is considered that both can exist uniformly in the pretreatment solution. As a result, the wetting spread of the pretreatment solution on the substrate is not uneven, and it is possible to obtain a printed material with excellent image quality, free from uneven color mixing, color unevenness, and inconsistencies in the degree of solid filling within the printed material. In addition, the resin particles (A1) and the water-soluble organic solvent and / or surfactant have a moderately high affinity for water, which can improve the spreading speed of water-based inkjet ink droplets, further improving the solid filling of the printed material. Moreover, since the pretreatment solution layer and the water-based inkjet ink containing water become more compatible, calcium ions, which are aggregation / thickening components, are more easily released and diffused, and it is considered that color mixing and bleeding are also improved.

[0031] In addition, since the resin particles (A1) are considered to be uniformly present within the pretreatment solution layer, the pretreatment solution layer will not dissolve unevenly when immersed in a basic solution. Furthermore, since the resin particles (A1) having the above SP value, as well as the water-soluble organic solvent and / or surfactant, are moderately compatible with water, printed materials having a layer of pretreatment solution containing these components will not, for example, repel basic solutions or excessively absorb moisture from the atmosphere. As a result, printed materials using the pretreatment solution of the present invention will have excellent blocking resistance and separation properties.

[0032] While resins with an SP value greater than 14.0 and / or an acid value greater than 60 are generally known, using large quantities of such resins in the pretreatment solution of the present invention may lead to the printed material becoming more susceptible to moisture absorption, potentially worsening its blocking resistance. Furthermore, excessive affinity for water can also degrade the storage stability of the pretreatment solution. Conversely, excessive use of resins with an SP value less than 9 can also lead to a decrease in water affinity, potentially resulting in a deterioration of the storage stability of the pretreatment solution.

[0033] Furthermore, the inventors have found that the above-mentioned effects can be further improved by setting the R / C ratio to 0.11 to 0.65, where R (g) is the amount of resin particles (A) contained in 100g of the pretreatment solution, and C (mmol) is the amount of millimoles of calcium ions contained in 100g of the pretreatment solution. As described above, simply adding resin to the pretreatment solution makes it difficult to achieve both color mixing and bleeding, color unevenness, and solid coverage, and may also worsen blocking resistance, separation properties, and storage stability of the pretreatment solution. However, by mixing in the above ratio, the release rate of the coagulation / thickening component and the spreading rate of the water-based inkjet ink droplets can be optimized, making it possible to obtain printed materials that achieve both color mixing and bleeding and solid coverage. Furthermore, the protective effect of water-soluble organic solvents and / or surfactants, as well as carboxylate ions, is suitably exhibited on the resin particles (A1), and the interaction between the resin particles (A1) and calcium ions can be suppressed. This improves the storage stability of the pretreatment solution and also suppresses deterioration of blocking resistance and separation properties.

[0034] As described above, in order to obtain a pretreatment solution that exhibits excellent separation properties in separation processes carried out under basic solutions, as well as excellent practical characteristics of printed materials such as image quality and blocking resistance, and furthermore, good storage stability, the adoption of the above configuration is absolutely essential.

[0035] Next, the constituent materials of the pretreatment solution of the present invention will be described in detail. Furthermore, the constituent materials of the aqueous inkjet ink used in combination with the pretreatment solution will also be described.

[0036] <Resin particles (A1)> The pretreatment solution of the present invention contains resin particles (A1). In this invention, "resin particles" are preferably those whose 50% diameter can be measured by the method described later, and more preferably those whose 50% diameter is 5 to 1,000 nm.

[0037] As described above, the resin particles (A1) contribute to improving the blocking resistance of printed materials and the separation of layers formed from water-based inkjet inks. Furthermore, by using a water-soluble organic solvent and / or surfactant with a specific SP value in combination, interaction with calcium ions can be suppressed, and the particles can be uniformly distributed in the pretreatment solution, thereby improving the image quality and storage stability of printed materials.

[0038] (SP value of resin particle (A1)) In this application, "SP value" is an abbreviation for Solubility Parameter, and in this invention, it is a value calculated by Fedor's estimation method, represented by the following formula 1 (where the unit is (cal / cm)). 3 ) 1 / 2 Use (as in this case).

[0039] Formula 1: (SP value) = (ΣEcoh / ΣV) 1 / 2

[0040] In Equation 1 above, Ecoh represents the cohesive energy defined for each functional group, and V represents the molar volume defined for each functional group. These values ​​of Ecoh and V are described in RFFedors, "Polymer Engineering & Science" (Vol. 14, No. 2, 1974, pp. 147-154).

[0041] Furthermore, in this application, the "SP value of resin particles (A1)" refers to a value obtained by weighting the SP values ​​of each raw material constituting the resin particles according to their respective molar ratios. For example, when styrene with an SP value of 9.2 and methacrylic acid with an SP value of 10.7 are reacted in a molar ratio of 3:1, the SP value of the resulting styrene-methacrylic acid resin will be approximately 9.2 × 3 ÷ (1 + 3) + 10.7 × 1 ÷ (1 + 3) ≈ 9.6.

[0042] Furthermore, in the present application, the description of "(mixed) SP value" refers to the SP value of the compound when there is only one type of compound for which the SP value is calculated, and when two or more types of compounds are included, it refers to the weighted average value of the SP values of the two or more types of compounds.

[0043] As described above, the SP value of the resin particles (A1) is a parameter that affects the blocking resistance of the printed matter, the separability of the layer formed from the aqueous inkjet ink, and the storage stability of the pretreatment liquid, etc. However, the inventors have found that the suitable SP value range to be satisfied in order to further improve these properties differs depending on the type of resin used as the resin particles (A1). Although the detailed factors are unclear, it is considered to be due to the structure of the main chain of the resin molecule. For example, when using a (meth)acrylic resin, a polyolefin resin, a styrene-(anhydrous)maleic acid resin, an olefin-(anhydrous)maleic acid resin, etc., in which the molecular chain forming the main chain is a hydrocarbon chain, as the resin particles (A1), its SP value is 9.0 to 13.5 (cal / cm 3 ) 1 / 2 is preferably, 9.0 to 12.5 (cal / cm 3 ) 1 / 2 is more preferably, and 9.0 to 11.5 (cal / cm 3 ) 1 / 2 is particularly preferably. On the other hand, when using a urethane (urea) resin, a polyester resin, an amine resin, etc., which have a hydrogen bond-forming site such as a urethane bond, an ester bond, or an amino group in the molecular chain forming the main chain, as the resin particles (A1), its SP value is 9.0 to 13.5 (cal / cm 3 ) 1 / 2 is preferably, 10.0 to 13.3 (cal / cm 3 ) 1 / 2 is more preferably, and 10.5 to 13.0 (cal / cm 3 ) 1 / 2 [[ID=**28**]]is particularly preferably. [[ID=**29**]] [[ID=**30**]]

[0044] [[ID=**31**]] [[ID=**32**]](Acid value of resin particles (A1))[[ID=**33**]] As described above, the acid value of the resin particles (A1) has a significant effect on improving blocking resistance and separation properties. Furthermore, by suppressing the amount of acid groups to an appropriate level, interaction with calcium ions can be inhibited, and by ensuring a sufficient amount of calcium ions that can function as aggregation / thickening components, it is possible to improve the image quality of printed materials and the storage stability of the pretreatment solution. From the viewpoint of more favorably exhibiting these effects and obtaining a pretreatment solution that is excellent in all aspects, including image quality, blocking resistance, separation properties, and storage stability of printed materials, the acid value of the resin particles (A1) is preferably 2 to 50 mg KOH / g, more preferably 3 to 40 mg KOH / g, even more preferably 4 to 30 mg KOH / g, and particularly preferably 5 to 25 mg KOH / g.

[0045] As mentioned above, acidic groups include carboxyl groups, sulfonic acid groups, phosphonic acid groups, etc., but in the pretreatment solution of the present invention, it is preferable to use carboxyl groups and / or phosphonic acid groups, and it is particularly preferable to use carboxyl groups, from the viewpoint of improving the blocking resistance and storage stability of printed materials.

[0046] In this application, "(resin) acid value" refers to the number of milligrams of potassium hydroxide required to neutralize the acid groups contained in 1 gram of the resin. In this application, when acid groups are not involved in the reaction to obtain the resin (for example, (meth)acrylic resin, urethane (urea) resin, urethane (urea)-(meth)acrylic resin, etc.), the theoretical value calculated by the following method shall be used as the acid value of the resin. On the other hand, when acid groups are involved in the reaction to obtain the resin (for example, polyester resin, etc.), the measured value measured by the following method shall be used as the acid value of the resin.

[0047] As an example of a method for calculating the theoretical value of acid value, if a resin contains Wa mass% of polymerizable monomers in the polymerizable monomers that make up the resin, each polymerizable monomer having na acid groups with a va value and a molecular weight of Ma, then its acid value (mgKOH / g) can be determined by the following formula 2.

[0048] Formula 2: (Acid value) = {(va × na × Wa) ÷ (100 × Ma)} × 56.11 × 1000

[0049] In formula 2 above, 56.11 is the molecular weight of potassium hydroxide.

[0050] On the other hand, the actual acid value is measured by, for example, potentiometric titration. Specifically, using the "AT-610 Automatic Potentiometric Titrator" manufactured by Kyoto Electronics Manufacturing Co., Ltd., the resin is dissolved in an ethanol / toluene mixed solvent, and then titrated with a 0.1 mol / L potassium hydroxide-ethanol solution. The acid value is then calculated from the resulting titration curve.

[0051] (Base value of resin particle (A1)) By allowing the resin particles (A1) to function as an aggregation / thickening component, the image quality is significantly improved, and the printed material exhibits excellent adhesion to the substrate. From this viewpoint, the resin particles (A1) may have cationic functional groups such as amino groups, ammonium groups, amide groups, and ureido groups. In this case, from the viewpoint of suitably achieving both the above-mentioned image quality and the separation properties of the layer formed from the aqueous inkjet ink from the printed material, as well as providing a pretreatment solution with excellent storage stability, the base number of the resin particles (A1) is preferably 0.5 to 40 mg KOH / g. Furthermore, from the viewpoint of achieving both storage stability, adhesion, and image quality of the pretreatment solution, the base number is more preferably 1 to 30 mg KOH / g, even more preferably 2 to 25 mg KOH / g, and particularly preferably 4 to 20 mg KOH / g.

[0052] In this application, "(resin) base number" refers to the amount of hydrochloric acid and the equivalent amount of KOH in mg required to neutralize the cationic functional groups contained in 1 g of the resin. Furthermore, as with the acid number described above, if cationic functional groups are not involved in the reaction to obtain the resin (e.g., (meth)acrylic resin, urethane resin, urethane-(meth)acrylic resin, polyester resin, etc.), the theoretical value calculated by the following method shall be used as the base number of the resin. On the other hand, if cationic functional groups are involved in the reaction to obtain the resin (e.g., urethane urea resin, urethane urea-(meth)acrylic resin, etc.), the measured value obtained by the following method shall be used as the base number of the resin.

[0053] As an example of a method for calculating the theoretical value of the acid value, if a resin contains Wc mass% of polymerizable monomers in the polymerizable monomers that make up the resin, each polymerizable monomer having nc cationic functional groups with a vc value and a molecular weight of Mc, then its base value (mgKOH / g) can be determined by the following formula 3.

[0054] Formula 3: (Base value) = {(vc × nc × Wc) ÷ (100 × Mc)} × 56.11 × 1000

[0055] On the other hand, the actual base number is measured by, for example, potentiometric titration. Specifically, using the "AT-610 Automatic Potentiometric Titrator" manufactured by Kyoto Electronics Manufacturing Co., Ltd., the resin is dissolved in an ethanol / toluene mixed solvent, and then titrated with a 0.1 mol / L hydrochloric acid-ethanol solution. The base number is then calculated from the resulting titration curve.

[0056] (Amount of polymerizable monomers containing long-chain alkyl groups in resin particles (A1)) In one preferred embodiment, the resin particles (A1) preferably contain 10 to 80 mol%, and more preferably 15 to 60 mol%, of a polymerizable monomer having a long-chain alkyl group (specifically, preferably a chain alkyl group having 6 to 36 carbon atoms that may be branched, more preferably a chain alkyl group having 8 to 30 carbon atoms that may be branched, even more preferably a chain alkyl group having 10 to 22 carbon atoms that may be branched, and particularly preferably a chain alkyl group having 12 to 18 carbon atoms that may be branched) based on the total molar amount of polymerizable monomers constituting the resin particles (A1). The inclusion of a certain amount of long-chain alkyl group in the resin particles (A1) improves the blocking resistance of the printed material and the storage stability of the pretreatment solution due to hydrophobicity and steric hindrance based on the long-chain alkyl group. Furthermore, when using the flotation method (details described later) in the separation process of the layer formed from water-based inkjet ink on a printed material on a paper substrate, the layer formed from the water-based inkjet ink becomes more easily adsorbed by air bubbles, thus improving the separation performance of the layer formed from the water-based inkjet ink on the printed material on the paper substrate.

[0057] (Amount of polymerizable monomers containing aromatic rings in resin particles (A1)) Furthermore, for the same reasons as described above for polymerizable monomers having long-chain alkyl groups, and also because of the excellent separation properties of the layer formed from aqueous inkjet ink from printed materials onto the plastic substrate, the resin particles (A1) preferably contain polymerizable monomers having aromatic rings in an amount of 5 to 80 mol%, and more preferably 10 to 75 mol%, relative to the total molar amount of polymerizable monomers constituting the resin particles (A1).

[0058] (Millimolary amount of ethylene oxide structure in resin particles (A1)) On the other hand, in one embodiment, the millimolar content of the ethylene oxide structure present in the resin particles (A1) is preferably 750 mmol / L or less, more preferably 450 mmol / L or less, even more preferably 250 mmol / L or less, and particularly preferably 100 mmol / L or less. When the millimolar content of the ethylene oxide structure is within the above range, the resin particles (A1) have a moderate affinity for water, so that, for example, the printed material does not repel basic solutions or absorb excessive moisture from the atmosphere. As a result, the blocking resistance of the printed material, the separation of layers formed from aqueous inkjet inks, and the storage stability of the pretreatment solution are improved.

[0059] In this application, if the type and content of polymerizable monomers constituting the resin particles (A1) are known, the value calculated by the following formula 4 shall be used as the millimolar content of the ethylene oxide structure. If the type and content of polymerizable monomers constituting the resin particles (A1) are unknown, for example, the content of polymerizable monomers having ethylene oxide groups and the number of moles of said ethylene oxide groups added shall be measured by NMR (nuclear magnetic resonance) measurement, and the millimolar content of the ethylene oxide structure shall be calculated by the following formula 4.

[0060] Formula 4: (EO structure content) = Σ[(n i ×W i )÷M i ]×1000

[0061] In the above formula 4, n i This is the number of moles of ethylene oxide groups added to polymerizable monomers having an ethylene oxide structure among the polymerizable monomers constituting the resin particles (A1), and W i This is the blending ratio (mass%) of the polymerizable monomer having the ethylene oxide structure relative to the total amount of polymerizable monomers constituting the resin particles (A1), and M i This is the molecular weight of the polymerizable monomer having the ethylene oxide structure.

[0062] (50% diameter of resin particle (A1)) The 50% diameter (D50) of the resin particles (A1) is more preferably 20 to 350 nm. Furthermore, from the viewpoint of improving the blocking resistance of the printed material and the storage stability of the pretreatment solution, and from the viewpoint of obtaining a printed material with excellent image quality and separation of layers formed from aqueous inkjet ink by rapidly and uniformly forming a film, and by uniformly dissolving the pretreatment solution layer when mixed with a basic solution, it is more preferably 30 to 300 nm, and particularly preferably 40 to 250 nm. The "50% diameter" refers to the cumulative 50% diameter (median diameter) on a volume basis measured by dynamic light scattering using a Microtrac-Bell Nanotrac UPA-EX150.

[0063] Furthermore, as a result of diligent research by the inventors, it was found that when the 50% diameter of the resin particles (A1) is RD50 and the millimolar amount of calcium ions contained in 100g of the pretreatment solution is C, the value expressed as RD50 / C is preferably 2 to 10, more preferably 3 to 8, and particularly preferably 3.5 to 7. Although the detailed factors are unknown, it is believed that resin particles (A1) that satisfy the above conditions can sufficiently cover the surface of the pretreatment solution layer even in the presence of calcium ions, and as a result, printed materials that achieve a balance of image quality, blocking resistance, and separation can be obtained.

[0064] If the pretreatment solution contains two or more types of resin particles (A1), the 50% diameter measured using an aqueous solution (a solution containing an aqueous solvent and components dispersed and / or dissolved in the aqueous solvent) containing the two or more types of resin particles (A1) shall be used as RD50 and used in the calculation of RD50 / C.

[0065] (Glass transition temperature of resin particle (A1)) When the resin particles (A1) include (meth)acrylic resin particles, the glass transition temperature (Tg) of the (meth)acrylic resin particles is preferably -10 to 75°C, more preferably 5 to 55°C, even more preferably 15 to 50°C, and particularly preferably 20 to 45°C, from the viewpoint of improving blocking resistance, separation of the aqueous inkjet ink layer from the printed material to the paper substrate, and storage stability.

[0066] On the other hand, in another preferred embodiment of the present invention, when the resin particles (A1) contain two types of (meth)acrylic resin particles, it is preferable that the glass transition temperature (Tg) of one of the resin particles is 25°C or lower, and the glass transition temperature of the other resin particle is 25°C or higher. Furthermore, it is preferable that the difference in glass transition temperatures between the two types of (meth)acrylic resin particles is 20°C or higher, and particularly preferable that it is 40°C or higher. By using two types of (meth)acrylic resin particles with different glass transition temperatures in this way, it is possible to significantly improve blocking resistance and separation properties compared to when each type of (meth)acrylic resin particle is used alone.

[0067] In this application, the glass transition temperature of (meth)acrylic resin particles is calculated using the following theoretical value. For example, for each of the i types of polymerizable monomers constituting the resin particles, the content relative to the total amount of polymerizable monomers constituting the resin particles is calculated using WA. i In mass%, the glass transition temperature (Tg) of the homopolymer of the polymerizable monomer is given. i When the temperature is (°C), the glass transition temperature (°C) of the resin particles can be determined by the following equation 5.

[0068] Formula 5: (Glass transition temperature) = 1 ÷ [Σ{WA i ÷(Tg i +273.2)}]-273.2

[0069] (Type of resin particle (A1)) Conventional known resins can be used as resin particles (A1), for example, (meth)acrylic resin, urethane (urea) resin, urethane (urea)-(meth)acrylic resin, polyester resin, polyolefin resin, styrene-(anhydride)maleic acid resin, olefin-(anhydride)maleic acid resin, vinyl acetate resin, ethylene-vinyl acetate resin, etc. Among these, it is preferable to use a resin selected from the group consisting of (meth)acrylic resin, urethane (urea) resin, urethane (urea)-(meth)acrylic resin, and polyester resin, as it is easier to keep within the above-mentioned SP value range and acid value range and can suitably exhibit the effects of the present invention.

[0070] In this application, "(meth)acrylic" means acrylic or methacrylic, "urethane (urea)" means urethane or urethane urea, and "(anhydride) maleic acid" means maleic acid or maleic anhydride. As will be described in detail later, (meth)acrylic resin may contain structures derived from styrene monomers such as styrene, methoxystyrene, vinyltoluene, and divinylbenzene as constituent units. Furthermore, the "urethane (urea)-(meth)acrylic resin" in this application is not included in "(meth)acrylic resin" and "urethane (urea) resin".

[0071] ((meth)acrylic resin particles) When using (meth)acrylic resin particles as resin particles (A1), you may use those synthesized according to conventionally known methods, or you may use commercially available products.

[0072] An example of a method for producing (meth)acrylic resin particles is a method of emulsion polymerization of ethylenically unsaturated monomers using surfactants or polymeric dispersants as emulsifiers. In particular, from the viewpoint of storage stability of the pretreatment solution, it is preferable to use (meth)acrylic resin particles containing a surfactant as an emulsifier as the resin particles (A1).

[0073] The following describes in more detail an example of a method for producing (meth)acrylic resin particles using a surfactant as an emulsifier. First, an aqueous medium (at least a medium containing water), an ethylenically unsaturated monomer, and a surfactant are mixed and stirred to obtain an emulsion. Next, the aqueous medium and a portion of the emulsion are placed in a reaction vessel, heated, the gas in the reaction vessel is replaced with nitrogen gas, a radical polymerization initiator is added, and then the remaining emulsion is gradually added dropwise. After the dropwise addition is complete, the reaction is allowed to continue for several more hours to obtain the desired (meth)acrylic resin particles.

[0074] As the above-mentioned ethylenically unsaturated monomers, acid-group-containing ethylenically unsaturated monomers, aromatic ethylenically unsaturated monomers, and other ethylenically unsaturated monomers can be used. Specifically, examples of acid-group-containing ethylenically unsaturated monomers include acrylic acid, methacrylic acid, carboxymethyl (meth)acrylate, carboxyethyl (meth)acrylate, acryloyloxyethyl succinic acid, methacryloyloxyethyl succinic acid, acryloyloxyethyl phthalic acid, methacryloyloxyethyl phthalic acid, acryloyloxyisobutyric acid, methacryloyloxyisobutyric acid, 2-sulfoethyl (meth)acrylate, acryloyloxyethyl phosphonic acid, methacryloyloxyethyl phosphonic acid, 2-(phosphonooxy)ethyl (meth)acrylate, vinyl sulfonic acid, styrene carboxylic acid, styrene sulfonic acid, styrene phosphonic acid, etc. Examples of aromatic ethylenically unsaturated monomers include styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene, m-methylstyrene, styrene carboxylic acid, styrene sulfonic acid, styrene phosphonic acid, vinyl naphthalene, benzyl acrylate, benzyl methacrylate, phenoxyethyl acrylate, phenoxyethyl methacrylate, phenoxydiethylene glycol acrylate, phenoxydiethylene glycol methacrylate, phenoxytetraethylene glycol acrylate, phenoxytetraethylene glycol methacrylate, phenoxyhexaethylene glycol acrylate, phenoxyhexaethylene glycol methacrylate, phenyl acrylate, phenyl methacrylate, etc. Examples of linear / branched alkyl-containing ethylenically unsaturated monomers include methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, pentyl (meth)acrylate, heptyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, etc. Examples of alicyclic alkyl group-containing ethylenically unsaturated monomers include cyclohexyl (meth)acrylate and isovonyl (meth)acrylate; Examples of fluorinated alkyl group-containing ethylenically unsaturated monomers include trifluoroethyl (meth)acrylate and heptadecafluorodecyl (meth)acrylate; As amide group-containing ethylenically unsaturated monomers, (meth)acrylamide, N-methoxymethyl-(meth)acrylamide, N-ethoxymethyl-(meth)acrylamide, N-propoxymethyl-(meth)acrylamide, N-butoxymethyl-(meth)acrylamide, N-pentoxymethyl-(meth)acrylamide, N,N-di(methoxymethyl)acrylamide, N-ethoxymethyl-N-methoxymethylmethacrylamide, N,N-di(ethoxymethyl)acrylamide, N-ethoxymethyl-N-propoxymethylmethacrylamide N,N-di(propoxymethyl)acrylamide, N-butoxymethyl-N-(propoxymethyl)methacrylamide, N,N-di(butoxymethyl)acrylamide, N-butoxymethyl-N-(methoxymethyl)methacrylamide, N,N-di(pentoxymethyl)acrylamide, N-methoxymethyl-N-(pentoxymethyl)methacrylamide, N,N-dimethylaminopropylacrylamide, N,N-diethylaminopropylacrylamide, N,N-dimethylacrylamide, N,N-diethylacrylamide, etc. Examples of hydroxyl group-containing ethylenically unsaturated monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol mono(meth)acrylate, 4-hydroxyvinylbenzene, 1-ethynyl-1-cyclohexanol, and allyl alcohol; Examples of keto-group-containing ethylenically unsaturated monomers include diacetone(meth)acrylamide and acetoseacetoxy(meth)acrylate; These can be listed below. These ethylenically unsaturated monomers may be used individually or in combination of multiple types.

[0075] The term "(meth)acrylate" above refers to at least one selected from "acrylate" and "methacrylate." As is clear from the above enumeration, vinyl sulfonic acid, styrene carboxylic acid, styrene sulfonic acid, styrene phosphonic acid, etc., are compounds that correspond to both acid group-containing ethylenically unsaturated monomers and aromatic ethylenically unsaturated monomers.

[0076] When using an acid group-containing ethylenically unsaturated monomer, a basic compound can be used as a neutralizing agent to increase the hydrophilicity of the resulting resin particles (A1). Examples of basic compounds that can be used include amines such as ammonia, trimethylamine, triethylamine, butylamine, dimethylaminoethanol, diethylaminoethanol, diethanolamine, triethanolamine, aminomethylpropanol, and morpholine; hydroxides such as potassium hydroxide and sodium hydroxide; and the like.

[0077] Furthermore, when separating the layer formed from the aqueous inkjet ink from the printed material, from the viewpoint of suitably promoting the dissolution of the pretreatment solution layer into the basic solution, amines with a boiling point of 100°C or higher at 1 atmosphere, such as dimethylaminoethanol, diethylaminoethanol, diethanolamine, triethanolamine, and aminomethylpropanol, and alkali metal hydroxides such as potassium hydroxide and sodium hydroxide can be suitably used as the neutralizing agent.

[0078] On the other hand, the radical polymerization initiator used when synthesizing (meth)acrylic resin is not particularly limited as long as it has the ability to initiate radical polymerization, and conventionally known oil-soluble polymerization initiators and water-soluble polymerization initiators can be used.

[0079] Examples of oil-soluble polymerization initiators include organic peroxides such as benzoyl peroxide, tert-butyl peroxybenzoate, tert-butyl hydroperoxide, tert-butyl peroxy(2-ethylhexanoate), tert-butyl peroxy-3,5,5-trimethylhexanoate, and di-tert-butyl peroxide; Azobis compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2,4-dimethylvaleronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), and 1,1'-azobis-cyclohexane-1-carbonitrile; These can be used. They can be used individually or in combination of two or more types.

[0080] On the other hand, in the production of the resin particles (A1) used in the pretreatment solution of the present invention, it is preferable to use a water-soluble polymerization initiator, and suitable candidates include ammonium persulfate (APS), potassium persulfate (KPS), hydrogen peroxide, and 2,2'-azobis(2-methylpropionamidine) dihydrochloride.

[0081] It is preferable to use 0.05 to 5.0% by mass of the radical polymerization initiator relative to the total amount of ethylenically unsaturated monomers.

[0082] Furthermore, when using a radical polymerization initiator, the polymerization temperature should be set to be equal to or higher than the polymerization initiation temperature of the radical polymerization initiator. For example, when using an organic peroxide as a radical polymerization initiator, a temperature of around 80°C is usually sufficient. While there are no particular restrictions on the polymerization time, it is typically 2 to 24 hours.

[0083] Furthermore, when carrying out emulsion polymerization, a reducing agent may be used in combination with a radical polymerization initiator if desired. The use of a reducing agent makes it easier to adjust the emulsion polymerization rate and to induce emulsion polymerization even at low temperatures.

[0084] Examples of such reducing agents include reducing organic compounds such as ascorbic acid, ersorbic acid, tartaric acid, citric acid, glucose, and metal salts such as formaldehyde sulfoxylate; reducing inorganic compounds such as sodium thiosulfate, sodium sulfite, sodium bisulfite, and sodium metabisulfite; ferrous chloride, rongalit, and thiourea dioxide. It is preferable to use these reducing agents in an amount of 0.05 to 5.0% by mass relative to the total amount of ethylenically unsaturated monomers.

[0085] Additionally, buffering agents such as sodium acetate, sodium citrate, and sodium bicarbonate, and / or chain transfer agents such as octyl mercaptan, 2-ethylhexyl thioglycolate, octyl thioglycolate, stearyl mercaptan, lauryl mercaptan, and tert-dodecyl mercaptan may be used as needed.

[0086] As mentioned above, when producing (meth)acrylic resin particles by emulsion polymerization, surfactants and polymeric dispersants can be used as emulsifiers. These materials may be used individually or in combination of two or more types.

[0087] Conventionally known compounds can be used as the surfactants mentioned above. For example, alkyl ethers (commercial products include Aqualon KH-05, KH-10, KH-20 from Daiichi Kogyo Seiyaku Co., Ltd., Adekaria Soap SR-10N, SR-20N from ADEKA Corporation, and Latemul PD-104 from Kao Corporation); sulfosuccinate esters (commercial products include Latemul S-120, S-120A, S-180P, S-180A from Kao Corporation, and Eleminol JS-2 from Sanyo Chemical Industries, Ltd.); alkylphenyl ethers or alkylphenyl esters (commercial products include Aqualon H-2885A, H-3855B, H-3855 from Daiichi Kogyo Seiyaku Co., Ltd.) Anionic reactive emulsifiers such as C, H-3856, HS-05, HS-10, HS-20, HS-30, ADEKA's Adekarya Soap SDX-222, SDX-223, SDX-232, SDX-233, SDX-259, SE-10N, SE-20N, etc.; (meth)acrylate sulfate ester type (commercial products include Nippon Emulsifier Co., Ltd.'s Antox MS-60, MS-2N, Sanyo Chemical Industries, Ltd.'s Eleminor RS-30, etc.); phosphate ester type (commercial products include Daiichi Kogyo Seiyaku Co., Ltd.'s H-3330PL, ADEKA's Adekarya Soap PP-70, etc.); Anionic nonreactive emulsifiers such as sodium oleate and other higher fatty acid salts, alkylaryl sulfonates such as sodium dodecylbenzenesulfonate, alkyl sulfate salts such as sodium lauryl sulfate, polyoxyethylene alkyl ether sulfate salts such as sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene alkylaryl ether sulfate salts such as sodium polyoxyethylene nonylphenyl ether sulfate, alkyl sulfosuccinate salts and their derivatives such as sodium monooctyl sulfosuccinate, sodium dioctyl sulfosuccinate, and sodium polyoxyethylene lauryl sulfosuccinate, and polyoxyethylene distyrenated phenyl ether sulfate salts; Polyoxyethylene alkyl ethers such as polyoxyethylene lauryl ether and polyoxyethylene stearyl ether; polyoxyethylene alkylphenyl ethers such as polyoxyethylene octylphenyl ether and polyoxyethylene nonylphenyl ether; sorbitan higher fatty acid esters such as sorbitan monolaurate, sorbitan monostearate, and sorbitan trioleate; polyoxyethylene sorbitan higher fatty acid esters such as polyoxyethylene sorbitan monolaurate; polyoxyethylene higher fatty acid esters such as polyoxyethylene monolaurate and polyoxyethylene monostearate; glycerin higher fatty acid esters such as oleic acid monoglyceride and stearate monoglyceride; nonionic nonreactive emulsifiers such as polyoxyethylene polyoxypropylene block copolymer and polyoxyethylene distyrenated phenyl ether; These are some examples.

[0088] It is preferable to use the emulsifiers listed above in an amount of 0.05 to 5.0% by mass relative to the total amount of ethylenically unsaturated monomers.

[0089] On the other hand, as the polymer dispersant, one resin selected from the group consisting of water-soluble (meth)acrylic resin, water-soluble styrene-(anhydride)maleic acid resin, and water-soluble α-olefin-(anhydride)maleic acid resin can be suitably used. In this case, it is preferable that the polymer dispersant has an ethylene oxide structure, from the viewpoint of particularly improving the blocking resistance and separation properties of the printed material, as well as the dispersion stability of the pretreatment solution. Furthermore, the amount of ethylene oxide structure contained in the polymer dispersant, calculated in the same manner as in the case of resin particles (A1), is preferably 350 to 2,000 millimol%, and particularly preferably 700 to 2,000 millimol%.

[0090] Examples of commercially available products that can be suitably used as polymer dispersants include DISPERBYK-190 and DISPERBYK-2015 from BIC-Chemie; SMA1000, SMA2000, SMA EF30, and SMA EF60 from CRAY VALLEY; and TEGO Dispers750W from Evonik.

[0091] The above polymeric dispersant is preferably used in an amount of 0.5 to 35% by mass relative to the total amount of ethylenically unsaturated monomers.

[0092] (urethane (urea) resin particles) When using urethane (urea) resin particles as resin particles (A1), you may use those synthesized according to conventionally known methods, or you may use commercially available products. However, in the pretreatment solution of the present invention, it is preferable to use urethane urea resin particles as resin particles (A1) from the viewpoint of obtaining printed materials with suitable viscoelasticity and improving blocking resistance.

[0093] An example of a method for producing urethane (urea) resin particles is a method in which a polyol (u1) and a polyisocyanate (u2) are subjected to a polyaddition reaction, and then a chain extender (u3) is added to carry out a chain extension reaction.

[0094] In the above example of the manufacturing method, the polyaddition reaction and chain extension reaction are preferably carried out in the presence of an organic solvent. Furthermore, the organic solvent is preferably inert with the isocyanate groups in the polyisocyanate (u2) raw material and capable of dissolving the hydrophilic raw material and product. Examples of such suitable organic solvents include ethers such as tetrahydrofuran and dioxane; esters such as ethyl acetate; ketones such as acetone, methyl ethyl ketone, and cyclohexanone; amides such as dimethylformamide and N-methylpyrrolidone; and so on. In particular, considering that the drying rate of the pretreatment solution can be accelerated when it is removed by vacuum distillation after the reaction is complete or when it is used without desolventing, it is more preferable to use an organic solvent with a lower boiling point than water.

[0095] (Polyol (u1)) Examples of polyols (u1) that can be used as raw materials for urethane (urea) resin particles include polymer polyols such as polyester polyols, polycarbonate polyols, and polyether polyols.

[0096] Examples of the above-mentioned polyester polyols include polyester polyols obtained by a condensation reaction between a polyol component and a dibasic acid component. Furthermore, the polyol component can be the same compound as polyol (e1) which can be used as a raw material for polyester resin particles as described later. Also, the dibasic acid component can be the compounds exemplified as aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids among polycarboxylic acids (e2) which can be used as a raw material for polyester resin particles as described later. In addition, polyester polyols obtained by ring-opening polymerization of cyclic ester compounds such as polycaprolactone, poly(β-methyl-γ-valerolactone), and polyvalerolactone may be used.

[0097] Furthermore, as the polyether polyol, for example, monopolymers or copolymers of tetrahydrofuran, ethylene oxide, propylene oxide, butylene oxide, etc.; condensates of hexanediol, methylhexanediol, heptanediol, octanediol, etc. can be used.

[0098] Furthermore, as the polycarbonate polyol mentioned above, for example, a reaction product of a polyol and a carbonate compound can be used. Specific examples of the carbonate compound include dialkyl carbonates, alkylene carbonates, diaryl carbonates, etc. Dimethyl carbonate and diethyl carbonate can be used as dialkyl carbonates, ethylene carbonate as an alkylene carbonate, and diphenyl carbonate as a diaryl carbonate. In addition to the polyols mentioned above as components of the polyester polyol, polybutadiene polyols, acrylic polyols, polysiloxane polyols, castor oil polyols, etc. can also be used as the polyol constituting the polycarbonate polyol.

[0099] The polymer polyols mentioned above may be used individually or in combination of multiple types. In particular, from the viewpoint of improving the blocking resistance and lamination suitability of printed materials, it is preferable to use polyester polyol and / or polycarbonate polyol as the polymer polyol.

[0100] As mentioned above, when using urethane (urea) resin particles as resin particles (A1), it is preferable to use urethane-urea resin particles from the viewpoint of obtaining printed materials with suitable viscoelasticity. Therefore, from the viewpoint of obtaining printed materials with particularly excellent blocking resistance, when using urethane (urea) resin particles as resin particles (A1), it is particularly preferable to use urethane-urea resin particles using polyester polyol as the polyol (u1), and / or urethane-urea resin particles using polycarbonate polyol as the polyol (u1).

[0101] As a method for dispersing urethane (urea) resin in an aqueous medium, a method using surfactants or polymer dispersants as emulsifiers may be employed, similar to the case of (meth)acrylic resin particles. However, in the present invention, from the viewpoint of suitably exhibiting the effects of the present invention described above, a method of dispersing in the aqueous medium by hydrophilic groups introduced into the resin skeleton without using these emulsifiers is preferred. From this viewpoint, it is also effective to use a polyol having an ethylene oxide structure as the polyol (u1), but from the viewpoint of improving the water resistance, abrasion resistance, and separation properties of the printed material, it is particularly preferable to use a polyol having acidic groups. Furthermore, among polyols having acidic groups, it is preferable to use a polyol having carboxyl groups from the viewpoint of excellent blocking resistance of the printed material and storage stability of the pretreatment solution.

[0102] Examples of polyols containing a carboxyl group include dimethylolalkanoic acids such as dimethylolacetic acid, dimethylolpropionic acid, dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolpentanoic acid, as well as dihydroxysuccinic acid, dihydroxypropionic acid, and dihydroxybenzoic acid. These carboxyl group-containing polyols may be used individually or in combination.

[0103] The above-mentioned acidic groups may be neutralized. As the neutralizing agent used for this neutralization, basic compounds that can be used to neutralize the acidic group-containing ethylenically unsaturated monomers constituting the (meth)acrylic resin particles described above can be used. Furthermore, the same applies to preferred neutralizing agents that can be selected from the viewpoint of improving the separation of the aqueous inkjet ink layer from the printed material as in the case of the (meth)acrylic resin particles described above.

[0104] On the other hand, low molecular weight polyols can be used as polyols (u1) for purposes such as increasing the concentration of urethane bonds in the urethane (urea) resin skeleton or introducing branched structures or tertiary amino groups into the urethane (urea) resin.

[0105] Examples of low molecular weight polyols include 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,4-butylenediol, dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-butanetriol, pentaerythritol, sorbitol, N,N-bis(2-hydroxypropyl)aniline, and the like.

[0106] Furthermore, by using an ethylenically unsaturated monomer having at least two hydroxyl groups and one ethylenically unsaturated group in the same molecule as the polyol (u1), it is also possible to introduce ethylenically unsaturated groups into the urethane (urea) resin backbone.

[0107] Examples of ethylenically unsaturated monomers having at least two hydroxyl groups and one unsaturated group in the same molecule include the reaction product of glycidol and acrylic acid, triols, and the reaction product of diisocyanate and 2-hydroxymethacrylate.

[0108] (Polyisocyanate (u2)) Examples of polyisocyanates (u2) to be reacted with polyol (u1) include aromatic, aliphatic, or alicyclic polyisocyanates.

[0109] Examples of aromatic polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylenediisocyanate, p-phenylenediisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, lysine diisocyanates, 3,3'-dimethyl-4,4'-biphenylenediisocyanate, 3,3'-dimethoxy-4,4'-biphenylenediisocyanate, 3,3'-dichloro-4,4'-4,4'-biphenylenediisocyanate, 1,5-naphthalenediisocyanate, 1,5-tetrahydronaphthalenediisocyanate, and m-tetramethylxylylene diisocyanate.

[0110] Examples of aliphatic polyisocyanates include tetramethylene diisocyanate, hexamethylene diisocyanate, and trimethylhexamethylene diisocyanate.

[0111] Examples of alicyclic polyisocyanates include isophorone diisocyanate, 1,4-cyclohexylene diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate.

[0112] Note that the polyisocyanates listed above may be used individually or in combination of multiple types.

[0113] Furthermore, dibutyltin dilaurate, tin octoate, dibutyltin di(2-ethylhexoate), lead 2-ethylhexoate, 2-ethylhexyl titanate, titanium ethyl acetate, iron 2-ethylhexoate, cobalt 2-ethylhexoate, zinc naphthenate, cobalt naphthenate, tetra-n-butyltin, stannous chloride, stannic chloride, iron chloride, etc. can be used as catalysts in the polyaddition reaction between polyol (u1) and polyisocyanate (u2).

[0114] (Chain extender (u3)) When using urethane urea resin as resin particles (A1), a chain extension reaction is performed during manufacturing. This chain extension reaction allows for further increasing the molecular weight of the polyurethane resin, and the introduction of urea bonds is expected to result in the development of excellent properties as resin particles (A1).

[0115] The chain extension reaction is carried out, for example, by producing a urethane prepolymer with an excess of isocyanate groups, then adding a chain extender (u3) and reacting it with the isocyanate groups. Examples of the chain extender (u3) include hydrazine, ethylenediamine, propylenediamine, hexamethylenediamine, nonamethylenediamine, xylylenediamine, isophoronediamine, piperazine, and their derivatives. Diamines such as phenylediamine, tolylenediamine, m-tetramethylxylylenediamine, N-(2-aminoethyl)ethanolamine, adipic acid dihydrazide, and isophthalic acid dihydrazide; Triamines such as diethylenetriamine; Diols such as 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis(β-hydroxyethoxy)benzene, 1,4-cyclohexanediol, bis(β-hydroxyethyl)terephthalate, and xylylene glycol; Triols such as trimethylolpropane; Pentaols such as pentaerythritol; Amino alcohols such as aminoethyl alcohol and aminopropyl alcohol; These can be used. Furthermore, by using the compounds listed above in combination with monoamines and / or monools, it is possible to adjust the molecular weight by controlling the chain extension reaction.

[0116] Furthermore, from the viewpoint of suppressing significant thickening of the resin solution, it is preferable to perform the chain extension reaction after neutralizing the urethane prepolymer.

[0117] (Urethane (urea)-(meth)acrylic resin particles) When using urethane (urea)-(meth)acrylic resin particles as resin particles (A1), they can be produced using methods such as: a method of producing (meth)acrylic resin particles using an ethylenically unsaturated monomer having a urethane bond in the molecule; a method of using a (meth)acrylic resin having a diol terminus as a polyol (u1) in the production of urethane (urea) resin particles; or a method of emulsion polymerization of an ethylenically unsaturated monomer using a water-soluble urethane (urea) resin as an emulsifier.

[0118] The ethylenically unsaturated monomer having the above-mentioned urethane bond can be obtained, for example, by reacting the above-mentioned hydroxyl group-containing ethylenically unsaturated monomer with a monoisocyanate, or by producing a urethane prepolymer with an excess of isocyanate groups, and then reacting the above-mentioned hydroxyl group-containing ethylenically unsaturated monomer with the urethane prepolymer in the presence of an alcohol such as butanol. Examples of the above-mentioned monoisocyanate include methyl isocyanate, ethyl isocyanate, propyl isocyanate, butyl isocyanate, and phenyl isocyanate.

[0119] Furthermore, the (meth)acrylic resin having the diol terminus can be obtained, for example, by polymerizing an ethylenically unsaturated monomer in solution using a chain transfer agent having one mercapto group and two hydroxyl groups. The ethylenically unsaturated monomer can be the same compound as the ethylenically unsaturated monomer used in the production of the (meth)acrylic resin described above.

[0120] (Polyester resin particles) When using polyester resin particles as resin particles (A), those synthesized according to conventionally known methods may be used, or commercially available products may be used. As an example of a synthesis method, a method of polycondensation of polyol (e1) and polycarboxylic acid (e2) may be used in the presence of an esterification reaction catalyst as needed. In addition to organotin compounds, organotitanium compounds, and organozirconium compounds, antimony trioxide and germanium dioxide can be used as the esterification reaction catalyst.

[0121] (Polyol(e1)) Examples of polyols (e1) that can be used as raw materials for polyester resin particles include diols such as 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol, polyethylene glycol (with 4 or more ethylene oxide groups), dipropylene glycol, tripropylene glycol, and polypropylene glycol (with 4 or more propylene oxide groups); Polyols (with 3 or more hydroxyl groups) such as glycerin, trimethylolpropane, diglycerin, and pentaerythritol; (Poly)ethylene oxide adducts of the above polyols (with 3 or more hydroxyl groups) (where the total number of ethylene oxide groups in one molecule is between 3 and 25); (Poly)propylene oxide adducts of the above polyols (with 3 or more hydroxyl groups) (where the total number of propylene oxide groups in one molecule is between 3 and 25); Bisphenols such as bisphenol A, bisphenol E, bisphenol F, and hydrogenated bisphenol A; (Poly)ethylene oxide adducts of the above-mentioned bisphenols (those with a total number of ethylene oxide groups in one molecule of 2 to 20); (Poly)propylene oxide adducts of the above bisphenols (those with a total number of propylene oxide groups in one molecule of 2 to 20) Examples include the following. In this application, the expression "(poly)" indicates that the number of structures in question (for example, in the case of "(poly)ethylene oxide," the ethylene oxide group) may be one or more.

[0122] The polyols (e1) listed above may be used individually or in combination of multiple types. In particular, it is preferable to use one or more selected from the group consisting of bisphenols, (poly)ethylene oxide adducts of bisphenols, and (poly)propylene oxide adducts of bisphenols as polyol (e1), in order to obtain printed materials with excellent blocking resistance and substrate adhesion, and especially in terms of excellent separation of the aqueous inkjet ink layer from the printed material to the paper substrate. It is especially preferable to use (poly)ethylene oxide adducts of bisphenols and / or (poly)propylene oxide adducts of bisphenols. Furthermore, from the viewpoint of more favorably exhibiting the above effects, when using (poly)ethylene oxide adducts of bisphenols and / or (poly)propylene oxide adducts of bisphenols, the molar amount of these adducts is preferably 50 mol% or more, more preferably 65 mol% or more, and especially preferably 80 mol% or more, relative to the total molar amount of polyol (e1).

[0123] (Polycarboxylic acid (e2)) On the other hand, the polycarboxylic acid (e2) to be reacted with the above polyol (e1) may be aromatic dicarboxylic acids such as phthalic anhydride, phthalic acid, 4-sulfophthalic acid, isophthalic acid, 5-sulfisophthalic acid, terephthalic acid, and 2-sulfoterephthalic acid; Aliphatic dicarboxylic acids such as fumaric acid, maleic acid, adipic acid, azelaic acid, sebacic acid, dimer acid, and hydrogenated dimer acid; Alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, decalindicarboxylic acid, and tetrahydrophthalic acid; Polycarboxylic acids (with 3 or more carboxyl groups), such as trimellitic acid and pyromellitic acid; These are some examples.

[0124] These polycarboxylic acids (e2) may be used individually or in combination of multiple types. In particular, aromatic dicarboxylic acids are preferred as polycarboxylic acids (e2) because they provide excellent blocking resistance and substrate adhesion, and especially because they allow for excellent separation of the aqueous inkjet ink layer from the printed material to the paper substrate. Furthermore, polycarboxylic acids (with 3 or more carboxyl groups) are also preferred from the viewpoint of particularly improving blocking resistance.

[0125] Furthermore, polyester resin particles having acidic groups can be obtained by methods such as reacting an excess molar amount of polycarboxylic acid (e2) with polyol (e1), or by using polycarboxylic acid (e2) having sulfonic acid groups. In this case, the acidic groups may be neutralized, and the neutralizing agent used for this neutralization can be a compound similar to the basic compound that can be used when neutralizing the acidic group-containing ethylenically unsaturated monomer constituting the (meth)acrylic resin particles described above. The same applies to preferred neutralizing agents that can be selected from the viewpoint of improving the separation of the aqueous inkjet ink layer from the printed material, as in the case of the (meth)acrylic resin particles described above.

[0126] (Resin particles (A2)) The pretreatment solution of the present invention may contain only one type of resin particle (A1), or two or more types in combination. It may also be used in combination with resin particles other than resin particle (A1) (hereinafter also referred to as "resin particle (A2)"). As resin particle (A2), the SP value is 9.0 to 14.0 (cal / cm³). 3 ) 1 / 2 Resin particles that are not and / or have an acid value of 1 to 60 mgKOH / g can be used. In one embodiment, the pretreatment solution of the present invention makes it possible to obtain printed materials with excellent image quality (color mixing and solid filling) and substrate adhesion while maintaining favorable blocking resistance and separation properties of the printed material, as well as storage stability of the pretreatment solution. From this viewpoint, the pretreatment solution of the present invention preferably contains polyolefin resin particles as resin particles (A2).

[0127] (Amount of resin particles) The total amount (R) of resin particles (A) contained in the pretreatment solution of the present invention is preferably 3 to 20% by mass, more preferably 4 to 15% by mass, and particularly preferably 5 to 10% by mass, based on solid content, of the total amount of the pretreatment solution, from the viewpoint of maintaining favorable blocking resistance and separation properties of the printed material while also providing favorable storage stability of the pretreatment solution and image quality of the printed material.

[0128] Furthermore, from the viewpoint of suitably exhibiting the effects of the present invention, the content of resin particles (A1) relative to the total amount of resin particles (A) is preferably 50 to 100% by mass, more preferably 65 to 100% by mass, even more preferably 75 to 100% by mass, and particularly preferably 80 to 100% by mass.

[0129] <Calcium ions> The pretreatment solution of the present invention contains calcium ions. As described above, calcium ions function as a flocculating / thickening component. In this invention, "calcium ions" include calcium that is miscible in the pretreatment solution, but does not include calcium contained in the precipitate from the pretreatment solution.

[0130] Calcium ions are added to the pretreatment solution, for example, in the form of a salt. In this case, carboxylate ions, as described later, may be used as the counter anion combined with the calcium salt, or other ions (e.g., organic acid ions, inorganic ions, etc.) may be used. In this case, it is preferable to select a counter anion that forms a calcium salt with a solubility of 1 to 70 g in 100 g of water at 20°C, in order to obtain printed materials with excellent blocking resistance and image quality over time without adversely affecting the separation properties of the layers formed from the aqueous inkjet ink, and to obtain a pretreatment solution with excellent storage stability without the formation of precipitates. The above solubility values ​​shall be those for the anhydrous calcium salt. Specific examples of counter anions that can be suitably used in this invention are described later.

[0131] In the pretreatment solution of the present invention, when the amount of millimoles of calcium ions contained in 100g of the pretreatment solution is denoted as C, C is preferably 5 to 70 millimoles, more preferably 10 to 60 millimoles, even more preferably 15 to 50 millimoles, and particularly preferably 20 to 40 millimoles. Within this range, the coagulation / thickening effect can be sufficiently expressed, and printed materials with excellent image quality can be obtained. Furthermore, since the action of resin particles (A) present in the pretreatment solution is not inhibited, the separation of the aqueous inkjet ink layer from the printed material is maintained, while also providing good blocking resistance.

[0132] Furthermore, as described above, since calcium ions, which are aggregation / thickening components, and resin particles (A1), which contribute to blockage resistance and separation, can coexist in the processing solution without adversely affecting each other, a pre-treatment solution with excellent storage stability, blockage resistance, separation, and image quality of printed materials can be obtained. From the viewpoint of obtaining a pre-treatment solution with excellent storage stability and excellent blockage resistance, separation, and image quality of printed materials, when the amount of the above-mentioned resin particles (A) contained in 100g of the pre-treatment solution in terms of solid content is R(g), the value expressed as R / C is 0.11 to 0.65, preferably 0.11 to 0.50, more preferably 0.15 to 0.50, and particularly preferably 0.20 to 0.40.

[0133] <Carboxylate ions> The pretreatment solution of the present invention contains carboxylate ions. As described above, calcium carboxylate salts, which consist of carboxylate ions and calcium ions, have low solubility in water but possess appropriate release and diffusion rates. Therefore, the release and diffusion rates of calcium ions to aqueous inkjet inks can be controlled within a suitable range, resulting in printed materials that are free from color bleeding and unevenness, and exhibit excellent solid coverage. Furthermore, it is believed that the carboxylate ions are positioned to protect the resin particles (A1), suppressing the approach of calcium ions and improving the storage stability of the pretreatment solution.

[0134] Furthermore, by using multiple carboxylate ions, an effect similar to the heterogeneous ion effect can be achieved, resulting in water solubility exceeding that of each calcium carboxylate alone, thus enabling further improvement in image quality.

[0135] In addition, it is preferable to use hydroxycarboxylate ions as carboxylate ions. Salts of hydroxycarboxylate ions and calcium ions (calcium hydroxycarboxylate salts) tend to maintain their solubility even if the composition of the liquid components changes due to drying. Furthermore, because they contain hydroxyl groups, pretreatment layers containing calcium hydroxycarboxylate salts have high affinity with aqueous inkjet inks printed later. As a result, even when printing aqueous inkjet ink on a completely dried pretreatment layer, for example, unevenness in the spread of the aqueous inkjet ink droplets is suppressed, and the solid filling of the printed material is further improved. Moreover, because they have multiple functional groups with strong hydrogen bonding properties, such as hydroxyl and carboxyl groups, they have high affinity with basic solutions, and therefore the separation of the aqueous inkjet ink layer from the printed material is also considered to be particularly improved.

[0136] For the reasons stated above, it is most preferable that the pretreatment solution of the present invention contains a plurality of carboxylate ions, and that one or more of them are hydroxycarboxylate ions, in order to obtain printed materials with particularly excellent image quality and separation, as well as improved storage stability.

[0137] Carboxylate ions are added to the pretreatment solution, for example, in the form of a carboxylic acid or a salt. When added in the form of a salt, the countercation may be a calcium ion, or other cations (e.g., alkali metal ions, alkaline earth metal ions (excluding calcium ions), trivalent metal ions, quaternary ammonium ions, etc.). However, since they will coexist with calcium ions in the pretreatment solution, regardless of the form in which they are added to the pretreatment solution, it is preferable, from the above viewpoint, to select carboxylate ions that form calcium salts with a solubility of 1 to 70 g in 100 g of water at 20°C. Specifically, examples include formate ions (17 g), acetate ions (28 g), propionate ions (38 g), butyrate ions (17 g), benzoate ions (2 g), lactate ions (3 g), gluconate ions (3 g), pantothenate ions (35 g), etc. (The values ​​in parentheses are the solubility of the calcium salt in 100 g of water at 20°C).

[0138] In the pretreatment solution of the present invention, when A is the total millimolar equivalent of carboxylate ions contained in 100g of the pretreatment solution, A is preferably 5 to 70 millimolar equivalents, more preferably 10 to 60 millimolar equivalents, even more preferably 15 to 50 millimolar equivalents, and particularly preferably 20 to 40 millimolar equivalents. Within this range, both the storage stability and image quality of the pretreatment solution described above can be achieved.

[0139] Furthermore, from the viewpoint of obtaining printed materials with particularly excellent storage stability of the pretreatment solution and image quality, the value expressed as C × 2 / A is preferably 0.8 to 1.1, and more preferably 0.9 to 1.1.

[0140] <Non-carboxylate ions> The pretreatment solution of the present invention may contain ions other than carboxylate ions (non-carboxylate ions) as counter anions for calcium ions, counter anions for other polyvalent metal ions (details of which will be described later), pH adjusters, etc. Examples of non-carboxylate ions include organic acid ions such as phosphonate ions, phosphate ions, phosphite ions, phosphonate ions, and phosphinate ions; as well as inorganic ions such as fluoride ions, chloride ions, bromide ions, iodide ions, sulfate ions, nitrate ions, carbonate ions, and bicarbonate ions. Among these, from the viewpoint described above, it is preferable to select a non-carboxylate ion that forms a calcium salt with a solubility of 1 to 70 g in 100 g of water at 20°C. Specifically, examples include dihydrogen phosphate ions (2 g), glycerophosphate ions (5 g), bicarbonate ions (17 g), and iodide ions (67 g).

[0141] In the pretreatment solution of the present invention, from the viewpoint of suitably exhibiting the effects of the carboxylate ions described above, when B is the millimolar equivalent of noncarboxylate ions contained in 100 g of the pretreatment solution, the value expressed as B / (A+B) is preferably 0 to 0.5, more preferably 0 to 0.3, and particularly preferably 0 to 0.1.

[0142] <Other coagulation / thickening ingredients> The pretreatment solution of the present invention may contain flocculating / thickening components other than calcium ions (hereinafter also referred to as "other flocculating / thickening components"). Specific examples of other flocculating / thickening components include polyvalent metal ions other than calcium ions (hereinafter also referred to as "other polyvalent metal ions") and water-soluble cationic polymers.

[0143] (Other polyvalent metal ions) If the pretreatment solution contains other polyvalent metal ions, it is preferable that these other polyvalent metal ions are divalent metal ions. Divalent metal ions are rapidly released upon contact with aqueous inkjet ink and exhibit excellent flocculation / thickening effects. Furthermore, compared to trivalent or higher metal ions, the rate of flocculation and / or thickening is not excessively high, and the wetting and spreading of aqueous inkjet ink on the substrate can be appropriately suppressed, resulting in printed materials with excellent image quality. Examples of divalent metal ions that can be suitably used in the pretreatment solution of the present invention include magnesium ions, zinc(II) ions, and iron(II) ions. Among these, magnesium ions are particularly preferred because they are released quickly into the aqueous inkjet ink they come into contact with, and the rate of aggregation and / or thickening is not excessive, resulting in printed materials with exceptionally good image quality.

[0144] Furthermore, when using other polyvalent metal ions, one type may be used alone, or two or more types may be used in combination. However, from the viewpoint of fully expressing the functions of the resin particles (A1), calcium ions, and carboxylate ions as described above, when the total amount of millimoles of other polyvalent metal ions contained in 100g of pretreatment solution is C2 (mmol), it is preferable that C≧C2, more preferably C≧C2×2, even more preferably C≧C2×5, and particularly preferably C≧C2×10.

[0145] Furthermore, other polyvalent metal ions are added to the pretreatment solution, for example, in the form of salts with the carboxylic acids mentioned above; in the form of salts or complex salts with the non-carboxylic acid ions and / or hydroxide ions mentioned above; or in the form of hydroxides.

[0146] (Water-soluble cationic polymer) When the pretreatment solution contains a water-soluble cationic polymer, it is preferable to use a polymer containing one or more structural units selected from the group consisting of diallylamine structural units, diallylammonium structural units, and epihalohydrin structural units. Using a pretreatment solution containing these polymers not only improves the blocking resistance and substrate adhesion of the printed material, but also increases the hydrophilicity of the pretreatment layer, resulting in good separation of the water-based inkjet ink layer from the printed material.

[0147] Similar to the case of calcium ions described above, it is preferable to select a water-soluble cationic polymer with a solubility of 5 g or more in 100 g of water at 20°C, because it provides a pretreatment solution with excellent blocking resistance over time and image quality, a pretreatment solution with excellent storage stability that does not produce precipitates, and furthermore, improves separation performance for the reasons mentioned above.

[0148] To determine whether a water-soluble cationic polymer has a solubility of 5 g or more in 100 g of water at 20°C, a sample is prepared by standing a mixture of 5 g of the water-soluble cationic polymer and 100 g of water at 20°C for 24 hours. The 50% diameter of the sample is then measured. If the water-soluble cationic polymer is only available as an aqueous solution (e.g., commercially available products), water is added or evaporated to obtain a sample with a solid content of 5 g per 100 g of water. The 50% diameter is a volume-based median diameter measured by dynamic light scattering, similar to the 50% diameter of resin particles (A1).

[0149] The type of water-soluble cationic polymer is not particularly limited, and any conventionally known cationic polymer can be used. Furthermore, polymers synthesized by conventionally known synthesis methods may be used, as well as commercially available products. Among these, polymers containing diallylammonium structural units are particularly preferred because they exhibit strong aggregation / thickening effects, making it easy to obtain printed materials with excellent image quality. In terms of availability and other factors, the hydrochloride or ethyl sulfate salts of diallyldimethylammonium and / or diallylmethylethylammonium are preferably selected as the diallylammonium structural units.

[0150] Examples of commercially available water-soluble cationic polymers containing diallylammonium structural units include PAS-H-1L, PAS-H-5L, PAS-24, PAS-84, PAS-J-81L, PAS-J-81, PAS-J-41, PAS-880, PAS-2351, PAS-2451 (manufactured by Nitto Boseki Medical Co., Ltd.); and Unisense FPA100L, FPA101L, FPA102L, FPA1000L, FPA1001L, FCA1000L, FCA1001L, FCA1002L, FCA1003L, FCA5000L, ZCA1000L, ZCA1001L, ZCA1002L (manufactured by Senka Co., Ltd.).

[0151] The weight-average molecular weight of the water-soluble cationic polymer is preferably 1,000 to 30,000, more preferably 2,500 to 45,000, and even more preferably 5,000 to 20,000. By setting the weight-average molecular weight of the water-soluble cationic polymer to 1,000 or more, the water-soluble cationic polymer can fully exhibit its function as an aggregation / thickening component, thereby improving image quality as well as the blocking resistance and abrasion resistance of the printed material. On the other hand, by setting the weight-average molecular weight to 30,000 or less, the pretreatment solution can be stably applied to the substrate, and because it has excellent affinity for basic solutions, the separation of the aqueous inkjet ink layer from the printed material is also good.

[0152] The weight-average molecular weight of the resin (polymer) in this application can be measured by GPC (gel permeation chromatography). Specifically, a GPC instrument (HLC-8120GPC, manufactured by Tosoh Corporation) equipped with a TSKgel column (manufactured by Tosoh Corporation) and an RI detector was used, with THF as the developing solvent and a flow rate of 1.0 ml / min. The measured molecular weight was then calculated as a converted molecular weight using polystyrene as the standard sample.

[0153] The water-soluble cationic polymer may be used alone or in combination of two or more types. However, from the viewpoint of fully expressing the functions of the resin particles (A1), calcium ions, and carboxylate ions as described above, when the total amount of water-soluble cationic polymer contained in 100g of pretreatment solution is PC(g), it is preferable that R ≥ PC, more preferably R ≥ PC × 2, and particularly preferably R ≥ PC × 5.

[0154] <Water-soluble organic solvents and / or surfactants> The pretreatment solution of the present invention comprises a water-soluble organic solvent and / or a surfactant, and its (mixed) SP value is 8.0 to 14.0 (cal / cm³). 3 ) 1 / 2 As described above, by using a water-soluble organic solvent and / or surfactant having an SP value similar to that of the resin particles (A1), the proximity of the resin particles (A1) to calcium ions is suppressed, thereby improving storage stability. Furthermore, because the resin particles (A1) and the water-soluble organic solvent and / or surfactant can exist uniformly in the pretreatment solution, it is possible to obtain printed materials with excellent image quality, free from uneven color mixing, color unevenness, and inconsistencies in the degree of solid filling. In addition, because the affinity to water is moderately high, and the pretreatment layer and the water-based inkjet ink containing water become more compatible, calcium ions, which are the coagulation / thickening components, are more easily released and diffused, which is thought to improve image quality.

[0155] From the viewpoint of suitably exhibiting the above effects, the (mixed) SP value of the water-soluble organic solvent and / or surfactant should be 9.0 to 13.6 (cal / cm³).3 ) 1 / 2 Preferably, it is 10.0-13.3 (cal / cm³). 3 ) 1 / 2 It is more preferable that the value be 10.5-13.0 (cal / cm³). 3 ) 1 / 2 It is particularly preferable that the above-mentioned effects are favorably expressed by reducing the difference with the SP value of the resin particles (A1), thereby obtaining printed materials with excellent image quality and separation, and furthermore, improving the storage stability of the pretreatment solution. Therefore, the absolute value of the difference between the (mixed) SP value of the water-soluble organic solvent and / or surfactant and the SP value of the resin particles (A1) is preferably 0 to 4.5, more preferably 0 to 3.5, even more preferably 0 to 3.0, and particularly preferably 0 to 2.5.

[0156] (Water-soluble organic solvent) When using a water-soluble organic solvent as a water-soluble organic solvent and / or surfactant, any conventionally known compound can be used. Furthermore, only one type of water-soluble organic solvent may be used, or two or more may be used in combination. When the above-mentioned hydroxycarboxylate ions are used as carboxylate ions, their affinity is improved, allowing the hydroxycarboxylate ions to be uniformly distributed throughout the pretreatment layer. This stabilizes the dispersion state of the resin particles (A1) and improves the affinity with the water-based inkjet ink, resulting in improved storage stability of the pretreatment solution and improved image quality of the printed material. Additionally, the wettability and drying properties of the pretreatment solution can be adjusted, facilitating uniform application and productivity on the substrate, as well as improving the adhesion and separation properties of the printed material. In this invention, "water-soluble organic solvent" refers to an organic compound that is liquid at 25°C and has a solubility of 1% by mass or more in water at 25°C.

[0157] In the pretreatment solution of the present invention, from the viewpoint of optimizing the wetting and drying properties of the pretreatment solution and improving the image quality, substrate adhesion, and separation properties of the printed material, it is preferable to use a water-soluble organic solvent having a static surface tension of 20 to 40 mN / m at 25°C, more preferably 20 to 35 mN / m, and particularly preferable 20 to 30 mN / m. Also from the same viewpoint, it is preferable to use a water-soluble organic solvent having a boiling point of 75 to 200°C at 1 atm, more preferably 75 to 180°C, and particularly preferable 80 to 160°C. The static surface tension of the water-soluble organic solvent (B) was measured by the Wilhelmy method at 25°C. Specifically, for example, it can be measured using a platinum plate with a Kyowa Interface Science Co., Ltd. "DY-300" at 25°C.

[0158] Furthermore, from the viewpoint of keeping the SP value within a suitable range, suitably exhibiting the above-mentioned effects, and improving the storage stability of the pretreatment solution, it is preferable to use a water-soluble organic solvent containing one or more hydroxyl groups in its molecular structure. In this case, in order to more suitably exhibit the above-mentioned effects, it is preferable that the content of the water-soluble organic solvent containing one or more hydroxyl groups in its molecular structure be 50 to 100% by mass, more preferably 70 to 100% by mass, and particularly preferable 90 to 100% by mass, relative to the total amount of the water-soluble organic solvent.

[0159] Examples of water-soluble organic solvents containing one or more hydroxyl groups in their molecular structure include monohydric alcohol solvents such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, and 2-butanol; 1,2-Ethanediol, 1,2-Propanediol, 1,3-Propanediol, 1,2-Butanediol, 1,3-Butanediol, 1,4-Butanediol, 1,2-Pentanediol, 1,5-Pentanediol, 1,2-Hexanediol, 1,2-Heptanediol, 2,2-Dimethyl-1,3-Propanediol, 2-Methyl-1,3-Propanediol, 2-Ethyl-2-Methyl-1,3-Propanediol, 3-Methyl-1,3-Butanediol Dihydric alcohol (glycol) solvents such as 3-methyl-1,5-pentanediol, 2-methyl-2-propyl-1,3-propanediol, 2-methylpentane-2,4-diol, 2-ethyl-1,3-hexanediol, 1,2-octanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol #200, polyethylene glycol #400, dipropylene glycol, tripropylene glycol, dibutylene glycol, etc. Glycol monoalkyl ether solvents such as ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monopentyl ether, diethylene glycol monohexyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, tetraethylene glycol monobutyl 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, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, 1,2-butylene glycol monomethyl ether, 2-methoxy-1-butanol, 3-methoxy-1-butanol, 3-methyl-3-methoxy-1-butanol; Chain-like polyol solvents such as glycerin, trimethylolpropane, 1,2,4-butanetriol, 1,2,6-hexanetriol, diglycerin, and polyglycerin; Examples include:

[0160] In addition to those exemplified above, other glycol dialkyl ether solvents include diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol butyl methyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol butyl methyl ether, triethylene glycol diethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol methyl ethyl ether, tetraethylene glycol butyl methyl ether, tetraethylene glycol diethyl ether, and other glycol dialkyl ether solvents; Chain-like nitrogen-containing compounds such as trimethylamine, triethylamine, butylamine, dimethylaminoethanol, diethylaminoethanol, diethanolamine, methyldiethanolamine, ethyldiethanolamine, triethanolamine, and aminomethylpropanol; Heterocyclic compounds such as 2-pyrrolidone, N-methylpyrrolidone, N-ethylpyrrolidone, ε-caprolactam, 3-methyl-2-oxazolidinone, 3-ethyl-2-oxazolidinone, γ-butyrolactone, γ-valerolactone, δ-valerolactone, ε-caprolactone, and morpholine; Chain-like amide solvents such as N,N-dimethyl-β-methoxypropionamide, N,N-dimethyl-β-ethoxypropionamide, N,N-dimethyl-β-butoxypropionamide, N,N-dimethyl-β-pentoxypropionamide, N,N-dimethyl-β-hexoxypropionamide, N,N-dimethyl-β-heptoxypropionamide, N,N-dimethyl-β-2-ethylhexoxypropionamide, N,N-dimethyl-β-octoxypropionamide, N,N-diethyl-β-butoxypropionamide, N,N-diethyl-β-pentoxypropionamide, N,N-diethyl-β-hexoxypropionamide, N,N-diethyl-β-heptoxypropionamide, and N,N-diethyl-β-octoxypropionamide; These can be used as water-soluble organic solvents.

[0161] The total amount of water-soluble organic solvent in the pretreatment solution is preferably 1 to 50% by mass, more preferably 2 to 40% by mass, and particularly preferably 3 to 30% by mass, relative to the total amount of the pretreatment solution. Keeping the water-soluble organic solvent content within the above range makes it easier to keep the SP values ​​of the water-soluble organic solvent and / or surfactant within the preferred range described above, thereby improving the storage stability and uniform application of the pretreatment solution, as well as the image quality, substrate adhesion, and separation properties of the printed material. It goes without saying that the (mixed) SP values ​​of the water-soluble organic solvent and / or surfactant must be considered when determining the above content.

[0162] In the pretreatment solution of the present invention, the content of a water-soluble organic solvent having a boiling point of 230°C or higher at 1 atmosphere 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), relative to the total amount of the pretreatment solution. By not including a water-soluble organic solvent with a boiling point of 230°C or higher, or by keeping the amount included within the above range, printed materials with excellent blocking resistance and image quality can be obtained, and the pretreatment solution will dry sufficiently.

[0163] Furthermore, for the same reasons as above, in addition to the content of water-soluble organic solvents having a boiling point of 230°C or higher at 1 atmosphere being less than 5% by mass of the total amount of pretreatment solution, it is preferable that the content of water-soluble organic solvents having a boiling point of 200°C or higher at 1 atmosphere be 10% by mass or less (or 0% by mass), more preferably 5% by mass or less (or 0% by mass), and particularly preferably 2% by mass or less (or 0% by mass), based on the total amount of pretreatment solution.

[0164] (Surfactants) When using a surfactant as a water-soluble organic solvent and / or surfactant, any conventionally known compound can be used. Furthermore, only one surfactant may be used, or two or more may be used in combination. In addition, the above-mentioned water-soluble organic solvent and surfactant can be used in combination. Examples of the above-mentioned surfactants include nonionic surfactants such as acetylenediol-based surfactants, siloxane-based surfactants, fluorine-based surfactants, (poly)oxyalkylene alkyl(phenyl) ether-based surfactants, (poly)oxyalkylene fatty acid ester-based surfactants, (poly)oxyalkylene alkylamine-based surfactants, (poly)oxyalkylene glycerin fatty acid ester-based surfactants, and (poly)oxyalkylene sorbitan fatty acid ester-based surfactants. Among these, acetylenediol-based surfactants, (poly)oxyalkylene alkyl ether-based surfactants, and (poly)oxyalkylene alkylamine-based surfactants are preferably used because they improve the wetting spread and uniform application of the pretreatment solution, eliminate the bias of the various components mentioned above within the layer of the pretreatment solution, and thus stably improve the image quality, substrate adhesion, and separation properties of the printed material, as well as because they keep the SP value within a suitable range and suitably exhibit the above-mentioned effects. The above-mentioned "alkyl(phenyl) ether" refers to at least one selected from "alkyl ether" and "alkylphenyl ether".

[0165] Examples of acetylenediol-based surfactants include 2,4,7,9-tetramethyl-5-decine-4,7-diol, 2,5,8,11-tetramethyl-6-dodecine-5,8-diol, hexadeca-8-in-7,10-diol, 6,9-dimethyl-tetradeca-7-in-6,9-diol, 7,10-dimethylhexadeca-8-in-7,10-diol, and their ethylene oxide and / or propylene oxide adducts.

[0166] Examples of commercially available acetylenediol-based surfactants include Surfinol 61, 82, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 420, 440, 465, 485, DF-110D, SE, SE-F, Dynol 604, 607 (manufactured by Air Products Co.), Olfin E1004, E1010, E1020, PD-001, PD-002W, PD-004, PD-005, EXP.4001, EXP.4200, EXP.4123, EXP.4300 (manufactured by Nisshin Chemical Industry Co., Ltd.).

[0167] In particular, ethylene oxide adducts of 2,4,7,9-tetramethyl-5-decine-4,7-diol and / or 2,5,8,11-tetramethyl-6-dodecine-5,8-diol are particularly suitable as acetylenediol-based surfactants because they can easily be kept within the SP value range of the aforementioned water-soluble organic solvents and / or surfactants, have a moderately high affinity for water, which is the main component of the pretreatment solution, and can exist uniformly in the pretreatment solution, thereby stably improving the image quality, substrate adhesion, and separation properties of printed materials. Furthermore, the number of moles of ethylene oxide groups present in these compounds is preferably 1 to 30 moles per molecule, more preferably 1 to 10 moles, and particularly preferably 1 to 5 moles.

[0168] Furthermore, as (poly)oxyalkylene alkyl ether-based surfactants and (poly)oxyalkylene alkylamine-based surfactants, compounds represented by the following general formulas 6 and 7 can be suitably used.

[0169] General formula 6: R 6 -O-[(EO) m -(PO) n ]-H

[0170] In general formula 6, R 6(EO) represents a branched linear alkyl group having 6 to 22 carbon atoms, or a branched linear alkenyl group having 6 to 22 carbon atoms, EO represents an ethylene oxide group, PO represents a propylene oxide group, m is an integer from 2 to 100, and n is an integer from 0 to 100. However, if n is not 0, (EO) m and (PO) n The order within the brackets [ ] is arbitrary and can be random or block-based.

[0171] General formula 7: [ka]

[0172] In general formula 7, R 7 represents a branched linear alkyl group having 6 to 22 carbon atoms, or a branched linear alkenyl group having 6 to 22 carbon atoms; EO represents an ethylene oxide group; PO represents a propylene oxide group; p and r are integers from 1 to 100; q and s are integers from 0 to 99; p > q and r > s. However, if q is not 0, (EO) p and (PO) q The order within the brackets [ ] is arbitrary and can be random or block-based. Also, if s is not 0, (EO) r and (PO) s The order within the brackets [ ] is arbitrary and can be random or block-based.

[0173] In addition, other siloxane-based surfactants that can be used include, for example, compounds represented by the following general formula 8.

[0174] General formula 8: [ka]

[0175] In the general formula (8), t is an integer of 1 or more, u is an integer of 0 or more, a is an integer of 1 to 20, b is an integer of 1 to 6, and t + u is 1 to 8. Also, R 81 is an alkylene group having 2 to 4 carbon atoms, and R 82 is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.

[0176] The total content of the surfactant in the pretreatment liquid of the present invention is preferably 0.1 to 10% by mass, more preferably 0.2 to 8% by mass, and particularly preferably 0.5 to 5% by mass with respect to the total amount of the pretreatment liquid. Needless to say, it is necessary to consider the (mixed) SP value of the water-soluble organic solvent and / or the surfactant when determining the above content.

[0177] <Water> The content of water contained in the pretreatment liquid of the present invention is preferably 50 to 95% by mass, more preferably 55 to 90% by mass, and particularly preferably 60 to 85% by mass with respect to the total amount of the pretreatment liquid. Water can enhance the mutual solubility of materials essential to the pretreatment liquid of the present invention, such as resin particles (A1), calcium ions, and carboxylate ions, and is an indispensable material for improving the storage stability of the pretreatment liquid.

[0178] <Other materials> In addition to the materials described above, the pretreatment liquid of the present invention may be added with materials such as a pH adjuster, a colorant, a thickener, a crosslinking agent, and a preservative, if necessary.

[0179] (pH adjuster) For example, from the viewpoint of reducing damage to members included in an apparatus (pretreatment liquid applying apparatus) used for applying the pretreatment liquid of the present invention and improving the storage stability of the pretreatment liquid by suppressing pH fluctuations over time, the pretreatment liquid of the present invention may contain a pH adjuster. There is no limitation on the material that can be used as the pH adjuster, and only one kind may be used, or two or more kinds may be used in combination.

[0180] The carboxylic acid mentioned above is not only a material that exhibits the functions described above, but also a pH adjuster. In addition, when basicizing the pretreatment solution, the following can be used: the chain-like nitrogen-containing compounds mentioned above; aqueous ammonia; alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; and alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium bicarbonate, and potassium carbonate. Furthermore, when acidifying the solution, inorganic acids such as hydrochloric acid, sulfuric acid, phosphoric acid, and boric acid can be used.

[0181] When printing the pretreatment solution onto a substrate using an inkjet method, in order to suppress adverse effects on other materials due to pH changes caused by the drying of water near the inkjet nozzle (and nozzle blockage caused by such adverse effects), maintain high productivity, and continuously exhibit the effects of the present invention, it is preferable to use a substance with a boiling point higher than that of water. On the other hand, in order to improve the abrasion resistance and water resistance of the printed material, it is preferable to use a substance that does not easily remain in the printed material. From these viewpoints, when basicizing the pretreatment solution, monoethanolamine, N-methyldiethanolamine, dimethylaminoethanol, diethylaminoethanol, and aminomethylpropanol are preferably used.

[0182] From the viewpoint of effectively exhibiting the effects described above, the amount of pH adjusting agent added is preferably 0.01 to 5% by mass, and more preferably 0.05 to 3% by mass, relative to the total amount of pretreatment solution.

[0183] <Coloring agent> The pretreatment solution of the present invention preferably contains substantially no colorants such as pigments or dyes. By using a pretreatment solution that does not contain colorants and is substantially transparent, printed materials that take advantage of the unique color and transparency of the substrate can be obtained. In this invention, "substantially absent" means that it is not permitted to intentionally add such materials to an extent that it hinders the manifestation of the effects of the present invention, and does not mean that the inclusion of impurities or by-products is excluded. Specifically, the pretreatment solution should not contain 2.0% by mass or more of the material, preferably 1.0% by mass or more, more preferably 0.5% by mass or more, and particularly preferably 0.1% by mass or more.

[0184] On the other hand, in another preferred embodiment, the pretreatment solution contains a white pigment as a coloring agent. By using a white pretreatment solution on a colored and / or transparent substrate, it is possible to obtain printed materials with particularly excellent clarity and visibility, and good image quality. When the pretreatment solution contains a white pigment, conventionally known materials, such as titanium dioxide, can be used as the white pigment.

[0185] <Physical properties of the pretreatment solution> The pretreatment solution of the present invention preferably has a viscosity of 5 to 200 mPa·s at 25°C, more preferably 5 to 180 mPa·s, even more preferably 8 to 160 mPa·s, and particularly preferably 8 to 140 mPa·s. A pretreatment solution satisfying the above viscosity range can be applied evenly to various types of substrates, resulting in printed materials with excellent image quality and blocking resistance. The viscosity of the pretreatment solution can be measured using, for example, an E-type viscometer (TVE25L viscometer manufactured by Toki Sangyo Co., Ltd.) or a B-type viscometer (TVB10 viscometer manufactured by Toki Sangyo Co., Ltd.), depending on the viscosity of the solution.

[0186] Furthermore, the static surface tension of the pretreatment solution of the present invention 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 obtaining printed materials with excellent image quality, blocking resistance, and separation properties of layers formed from aqueous inkjet inks, by imparting suitable wetting spreadability to various types of substrates and forming a uniform and even layer of the pretreatment solution. Note that the static surface tension in this specification can be measured in the same manner as the surface tension of the water-soluble organic solvent described above.

[0187] <Method for producing pretreatment solution> The pretreatment solution of the present invention, consisting of the components described above, can be produced, for example, by adding resin particles (A1), calcium carboxylate, a water-soluble organic solvent and / or surfactant, and optionally pH adjusters, preservatives, and other materials listed above, stirring and mixing, and then filtering as necessary. However, the method for producing the pretreatment solution is not limited to the method described above. For example, when using a white pigment as a coloring agent, a white pigment dispersion containing the white pigment and water may be prepared in advance and then mixed with the resin particles (A1), calcium carboxylate, and water-soluble organic solvent and / or surfactant. When stirring and mixing, the mixture may be heated to a temperature of 40 to 100°C as needed. In this case, it is preferable to heat it to a temperature below the minimum film-forming temperature (MFT) of the resin particles (A1).

[0188] <Water-based inkjet ink> The pretreatment solution of the present invention can be used in combination with one or more types of aqueous inkjet inks in the form of an ink set. Preferably, the aqueous inkjet ink contains a pigment, a resin, and water. It may also further contain a water-soluble organic solvent, a surfactant, etc.

[0189] The pigments contained in water-based inkjet inks are preferable because they offer excellent color development and lightfastness, resulting in printed materials with superior image quality, and furthermore, they do not dissolve in basic solutions during separation, allowing for the creation of uncolored recycled substrates. For these reasons, blue pigments such as CI Pigment Blue 15:3, 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, 180, 185, and 213; black pigments such as carbon black; and white pigments such as titanium dioxide are preferable.

[0190] Furthermore, the aqueous inkjet ink preferably contains, as a resin, a polymer dispersant for pigment dispersion used to disperse the above-mentioned pigment, and / or a binder resin used to bind the layer formed from the aqueous inkjet ink (aqueous inkjet ink layer) to the layer of the pretreatment liquid, and it is particularly preferable that it contains at least a binder resin. The binder resin is preferably selected from the group consisting of resin particles (A1) that can be used as resin particles, namely (meth)acrylic resin particles, urethane (urea) resin particles, urethane (urea)-(meth)acrylic resin particles, and polyester resin particles, and has an SP value of 9.0 to 14.0 (cal / cm²). 3 ) 1 / 2 Resin particles having an acid value of 1 to 60 mg KOH / g are preferably used. Furthermore, if the binder resin has acidic groups, these acidic groups may be neutralized with a neutralizing agent. In this case, a basic compound that can be used to neutralize the acidic group-containing ethylenically unsaturated monomers constituting the (meth)acrylic resin particles, as described above, can be used as the neutralizing agent.

[0191] On the other hand, when separating a layer formed from water-based inkjet ink from a printed material, if the layer formed from the water-based inkjet ink dissolves excessively in a basic solution, the resulting recycled substrate will be colored by the pigment contained in the water-based inkjet ink. Therefore, from the viewpoint of improving the separability of the layer formed from water-based inkjet ink, it is preferable to suppress the dissolution of the layer formed from water-based inkjet ink into a basic solution. From this viewpoint, it is preferable to use amines such as ammonia, trimethylamine, triethylamine, butylamine, dimethylaminoethanol, diethylaminoethanol, and aminomethylpropanol, which have a boiling point of 170°C or less at 1 atmosphere, as the neutralizing agent.

[0192] Furthermore, when the water-based inkjet ink contains water-soluble organic solvents or surfactants, from the viewpoint of improving compatibility and affinity with the pretreatment solution, the (mixed) SP value should be 8.0 to 14.0 (cal / cm³), similar to the case of the pretreatment solution. 3 ) 1 / 2 It is preferable that this is the case. Also for similar reasons, when using a water-soluble organic solvent, it is preferable that it contains a glycol monoalkyl ether solvent and / or a dihydric alcohol solvent, and when using a surfactant, it is preferable to use an acetylenediol surfactant.

[0193] Furthermore, when the aqueous inkjet ink contains a water-soluble organic solvent, in order to obtain printed materials with excellent image quality even at high speeds and excellent ejection stability when used in combination with the pretreatment solution of the present invention, it is preferable that the average weighted boiling point of the water-soluble organic solvent contained in the aqueous inkjet ink at 1 atmosphere be 145 to 215°C, more preferably 150 to 200°C, and particularly preferable 155 to 190°C. In addition, in order to obtain printed materials without image quality defects such as color bleeding and with good blocking resistance when combined with the pretreatment solution, it is preferable that the amount of water-soluble organic solvent with a boiling point of 220°C or higher at 1 atmosphere be 5% by mass or less (may be 0% by mass), particularly preferable 2% by mass or less (may be 0% by mass), and particularly preferable 1% by mass or less (may be 0% by mass) relative to the total amount of aqueous inkjet ink.

[0194] Furthermore, if the water-based inkjet ink contains a surfactant, the amount of the surfactant added is preferably 0.01 to 5.0% by mass, and more preferably 0.05 to 3.0% by mass, relative to the total amount of the water-based inkjet ink.

[0195] <Manufacturing methods for printed materials> Next, we will explain in detail the process and other aspects of the manufacturing method for printed materials using the pretreatment solution and water-based inkjet ink described above.

[0196] When manufacturing printed materials using the pretreatment solution and aqueous inkjet ink described above, it is preferable to perform the steps of applying the pretreatment solution to the substrate (1) and printing the aqueous inkjet ink onto the substrate obtained in step (1) in this order.

[0197] <Pretreatment solution application step (1)> In step (1), the method for applying the pretreatment liquid of the present invention onto a substrate may be a method of non-contact printing of the pretreatment liquid onto the substrate, such as an inkjet printing method, or a method of applying the pretreatment liquid by contact with the substrate. Specific examples of the inkjet printing method are the same as those in the case of aqueous inkjet ink, and details will be described later. On the other hand, when selecting a coating method in which the pretreatment liquid is brought into contact as the method for applying the pretreatment liquid, a gravure coater, an offset gravure coater, a doctor coater, a bar coater, a blade coater, a flexo coater, an air doctor coater, a roll coater, etc. can be used. Among them, it matches the characteristics of the pretreatment liquid of the present invention, can be stably, uniformly and easily applied to various substrates described later, and the adjustment of the coating amount is easy. For example, by adjusting the coating amount according to the substrate, the balance of the image quality, blocking resistance, and separability of the layer formed from the aqueous inkjet ink of the printed matter is easy to achieve. Therefore, a gravure coater, an offset gravure coater, and a flexo coater can be preferably used.

[0198] In the present application, "application of the pretreatment liquid" is used as a general term for non-contact printing of the pretreatment liquid and coating of the pretreatment liquid by contact with the substrate.

[0199] From the viewpoint of obtaining a printed matter excellent in all of image quality, blocking resistance, and separability of the layer formed from aqueous inkjet ink, the thickness of the layer of the pretreatment liquid immediately after application is preferably 1 to 10 μm, more preferably 2 to 8 μm, and particularly preferably 3 to 7 μm.

[0200] <Drying step (1A) after application of the pretreatment liquid> In step (2) above, the drying state of the pretreatment liquid on the substrate when printing the aqueous inkjet ink can be arbitrarily selected.

[0201] In one embodiment, it is preferable to dry the pretreatment solution before printing the aqueous inkjet ink, that is, to keep the total amount of volatile components remaining in the pretreatment solution on the substrate immediately before the droplets of aqueous inkjet ink land on the substrate at 5% by mass or less (more preferably 3% by mass or less, and particularly preferably 2% by mass or less) relative to the total amount of volatile components in the pretreatment solution before application to the substrate. This is because printing the aqueous inkjet ink after the pretreatment solution has dried prevents the aqueous inkjet ink that lands later from drying poorly, resulting in a printed material with excellent blocking resistance.

[0202] In that case, it is preferable to include a step to dry the pretreatment liquid on the substrate (hereinafter also referred to as "drying step (1A)") after step (1) and before step (2). There are no particular restrictions on the drying method of the pretreatment liquid in drying step (1A), and conventionally known methods such as heating drying, hot air drying, infrared drying, microwave drying, drum drying, and high-frequency dielectric heating can be used. These drying methods may be used individually or in combination, but it is preferable to use hot air drying and / or infrared drying in order to reduce damage to the substrate and dry it efficiently.

[0203] <Pre-drying process after application of pre-treatment solution (1B)> On the other hand, in another embodiment, the aqueous inkjet ink may be printed on a layer of wet pretreatment liquid. In this application, "wet pretreatment liquid" means that, immediately before droplets of aqueous inkjet ink land on the substrate, the total amount of volatile components remaining in the pretreatment liquid is 50% by mass or more (more preferably 75% by mass or more, and particularly preferably 90% by mass or more) of the total amount of volatile components in the pretreatment liquid before application to the substrate. By printing aqueous inkjet ink on a wet pretreatment liquid, it is possible to obtain printed materials with excellent image quality and separation.

[0204] In that case, it is preferable to either not include a drying step after step (1) and before step (2), or to include a step (hereinafter also referred to as "pre-drying step (1B)") in which only a portion of the pre-treatment liquid on the substrate is dried. As for the drying method of the pre-treatment liquid in the pre-drying step (1B), from the viewpoint of preventing excessive drying of the pre-treatment liquid, for example, room temperature air drying or visible light drying can be preferably used. Alternatively, after adjusting the energy applied to the printed material, the methods exemplified above as methods that can be used in drying step (1A) may be adopted. Furthermore, these drying methods may be used individually or in combination.

[0205] <Water-based inkjet printing process (2)> In step (2), in order to realize the effects of the present invention, it is preferable that the aqueous inkjet ink is printed so that at least a portion of it overlaps with the portion to which the pretreatment solution has been applied, and it is even more preferable that it is printed so that it overlaps only with the portion to which the pretreatment solution has been applied.

[0206] In step (2), the same aqueous inkjet ink may be filled into multiple inkjet heads, and the aqueous inkjet ink may be printed onto the substrate from each of the said inkjet heads. Alternatively, the aqueous inkjet ink filled into the inkjet head may be ejected from the inkjet head while it is heated. In this case, the heating temperature of the aqueous inkjet ink in the inkjet head is preferably 30 to 50°C, and particularly preferably 30 to 45°C. Furthermore, the aqueous inkjet ink may be printed while heating the substrate from, for example, the back side (the side opposite to the side on which the aqueous inkjet ink is printed). In this case, it is preferable to heat the surface on which the aqueous inkjet ink is printed to a temperature of 30 to 55°C, and particularly preferably 35 to 50°C.

[0207] Furthermore, the water-based inkjet ink may contain multiple water-based inkjet inks. Specifically, the water-based inkjet ink may contain two or more inks selected from the group consisting of cyan ink, magenta ink, yellow ink, black ink, and white ink.

[0208] <Inkjet printing method> As described above, the aqueous inkjet ink is printed onto the substrate using an inkjet printing method. Alternatively, an inkjet printing method may be selected as the method for applying the pretreatment liquid of the present invention onto the substrate. In this case, as the inkjet printing method used for these prints, a single-pass method may be adopted in which the aqueous inkjet ink is ejected onto the substrate only once, or a serial method may be adopted in which the aqueous inkjet ink is ejected while a short shuttle head is scanned back and forth in a direction perpendicular to the transport direction of the substrate. Specific examples of the single-pass method include a method in which the inkjet head is scanned onto a stationary substrate only once (referred to as the "head-scanning single-pass method" in this application), and a method in which the substrate is passed only once under a fixed inkjet head for printing (referred to as the "head-fixed single-pass method" in this application). In the present invention, any of the above methods may be adopted, but the head-fixed single-pass method is preferred because it eliminates the need to adjust the ejection timing of the aqueous inkjet ink in relation to the scanning of the inkjet head, and because it is less likely to cause misalignment of the landing position, resulting in printed materials with excellent image quality.

[0209] Furthermore, the design resolution of the inkjet head used in a fixed-head single-pass system is preferably 600 dpi (Dots Per Inch) or higher, and more preferably 720 dpi or higher, in order to obtain images with excellent image quality.

[0210] <Base material> Printed materials produced using the pretreatment solution and aqueous inkjet ink of the present invention can be suitably printed on conventionally known substrates, and in particular, paper substrates and plastic substrates can be suitably used in order to effectively utilize the excellent blocking resistance and separation properties of the printed materials. Examples of paper substrates that can be used include fine paper, medium-quality paper, plain paper (PPC paper), kraft paper, newsprint, liner paper (corrugated cardboard), lightly coated paper, coated paper, art paper, matte coated paper, and cast coated paper. Examples of plastic substrates that can be used include polyvinyl chloride sheets, polyethylene terephthalate (PET) film, polypropylene film, polyethylene film, nylon film, polystyrene film, and polyvinyl alcohol film. In addition to paper substrates and plastic substrates, printed materials may also be produced using fabric substrates such as nylon fibers, polyester fibers, cotton, silk, and nonwoven fabrics; metal substrates such as aluminum and iron; and glass substrates.

[0211] These substrates may have a smooth or uneven surface, and may be transparent, translucent, or opaque. Furthermore, two or more of the above-listed substrates may be laminated together, or a release adhesive layer may be provided on the opposite side of the surface to which the pretreatment solution is applied. In addition, an adhesive layer may be provided on the printed surface after the printed material has been produced. Moreover, the substrate used in printing according to the present invention may be in the form of a roll or a sheet.

[0212] Furthermore, when using a plastic substrate, it is particularly preferable to use PET film, polypropylene film, polyethylene film, or nylon film among those listed above, from the viewpoint of fully exhibiting the functionality of the pretreatment solution of the present invention. In addition, from the viewpoint of applying the pretreatment solution of the present invention uniformly and without unevenness, and particularly improving the adhesion of the printed material to the substrate, it is also preferable to apply a surface modification method such as corona treatment or plasma treatment to the plastic substrate before applying the pretreatment solution.

[0213] <Coating treatment> Printed materials produced using the pretreatment solution of the present invention and aqueous inkjet ink can be coated on the printed surface as needed. Specific examples of such coating treatments include coating and printing with a coating composition, and lamination using methods such as dry lamination, solvent-free lamination, and extrusion lamination. Any of these methods may be selected, or a combination of several may be used.

[0214] Furthermore, when applying a coating treatment to a printed material by coating or printing with a coating composition, either a method that prints without contact with the substrate, such as an inkjet printing method, or a method that applies the coating composition by bringing it into contact with the substrate, may be used as the coating or printing method.

[0215] Furthermore, when laminating printed materials to produce a laminate, the adhesive used to laminate the sealant substrate is preferably composed of a mixture of a polyol component and a polyisocyanate component. In this case, it is preferable that the polyol component contains a polyester polyol, as this provides good wettability to the substrate surface, the pretreatment layer, and the layer formed from the aqueous inkjet ink, and also results in excellent laminate strength of the resulting laminate. Similarly, for the same reason, it is preferable that the polyisocyanate component contains a polyether-based urethane resin with isocyanate group ends. The amount of polyisocyanate component is preferably 50 to 80% by mass relative to the polyol component.

[0216] Examples of sealant substrates used in the above lamination process include polypropylene films and polyethylene films, such as unoriented polypropylene (CPP) film and linear short-chain branched polyethylene (LLDPE) film. Alternatively, a film with a metal (oxide) vapor-deposited layer, such as aluminum oxide, may be used.

[0217] <Method for separating printed materials> Next, a method for separating the water-based inkjet ink layer from a printed material produced using the pretreatment solution and water-based inkjet ink described above will be explained in detail below. It is preferable that the pretreatment layer used to separate the layer formed from the water-based inkjet ink is in a dry state.

[0218] <Method for separating layers of water-based inkjet ink from a paper substrate> As a method for separating the aqueous inkjet ink layer from a printed material on a paper substrate using the pretreatment solution and aqueous inkjet ink of the present invention, for example, a method including a wet dissociation step and an aqueous inkjet ink layer removal step can be used.

[0219] In the wet disintegration process, the printed material on the paper substrate is immersed in a basic solution, and while adjusting the pulp concentration, disintegration temperature, etc., the pulp of the printed material is loosened to form a slurry, the layer of pretreatment liquid is dissolved in the basic solution, and the layer formed from aqueous inkjet ink is separated from the pulp. The basic solution used in the wet disintegration process contains at least a basic material and a liquid medium (preferably an aqueous medium), and may also contain bleaching agents, bleaching aids, disintegration accelerators, deinking agents, defoaming agents, etc.

[0220] As the basic material mentioned above, for example, alkali metal hydroxides can be used, and sodium hydroxide (caustic soda) or potassium hydroxide (caustic potash) are preferably used from the viewpoint of basicity strength (large pKb value), high solubility in aqueous media, bonding ability with acid groups in the resin particles (A1) contained in the pretreatment layer, and availability. The amount added is preferably 0.05 to 3.5% by mass relative to the pulp contained in the printed material, and particularly preferably 0.1 to 2.5% by mass. By keeping it within this range, the sodium hydroxide or potassium hydroxide can be sufficiently immersed in the pulp and swell the pulp, making it easier to separate the layer formed from the aqueous inkjet ink. Furthermore, the amount of alkali metal ions can be sufficient to form an ionic bond with the acid groups in the resin particles (A1) contained in the pretreatment layer. As a result, the separation of the aqueous inkjet ink layer from the printed material to the paper substrate is good.

[0221] Furthermore, a bleaching agent such as hydrogen peroxide or hypochlorous acid (salt) may be added to the basic solution in an amount of 0.3 to 4% by mass, preferably 0.5 to 3% by mass, relative to the pulp contained in the printed material. In addition, sodium silicate may be added as a bleaching aid and disintegration accelerator in an amount of 0.3 to 4% by mass, preferably 0.5 to 3% by mass, relative to the pulp contained in the printed material. In addition, a deinking agent may be added in an amount of 0.01 to 0.5% by mass, preferably 0.02 to 0.3% by mass, relative to the pulp contained in the printed material.

[0222] Furthermore, the following can be used as deinking agents as described above and below: fatty acid compounds such as fatty acids (oleic acid, stearic acid, coconut fatty acid, palm oil fatty acid, beef tallow fatty acid, etc.), fatty acid salts, fatty acid esters, polyoxyalkylene fatty acids, polyoxyalkylene fatty acid esters; higher alcohol compounds such as higher alcohols (oleyl alcohol, stearyl alcohol, isostearyl alcohol, behenyl alcohol, etc.), higher alcohol sulfates, polyoxyalkylene higher alcohols, polyoxyalkylene higher alcohol sulfates, polyoxyalkylene higher alcohol sulfate esters; and other surfactants such as alkylbenzene sulfonates, alkyl sulfate esters, alkylphenols. Furthermore, commercially available deinking agents containing the compounds listed above include DI-767, DI-7020, DI-7250, Lunac OV, Lunac S-50V, Lunac S-70V (all manufactured by Kao Corporation); DIA-Z series, DIZ-Y series (both manufactured by Nisshin Chemical Research Institute Co., Ltd.); Neocore FW series (manufactured by Toho Chemical Industry Co., Ltd.); and Daihope series (manufactured by Daiichi Industrial Pharmaceutical Co., Ltd.). The deinking agent may consist of a single component or a mixture of two or more components.

[0223] In the wet disintegration process, conventionally known equipment such as pulpers, disc refiners, homogenizers, and kneaders can be used without limitation. Furthermore, the temperature of the mixture during the wet disintegration process is preferably 15 to 50°C, and particularly preferably 25 to 50°C. In addition, the pulp concentration in the mixture during the wet disintegration process is preferably 2 to 35% by mass, more preferably 4 to 30% by mass, and particularly preferably 6 to 25% by mass.

[0224] Furthermore, the duration of the wet disintegration process carried out within the above preferred temperature range is preferably 10 to 60 minutes, and particularly preferably 15 to 40 minutes.

[0225] In the aqueous inkjet ink layer removal step, the layer (or fragments thereof) formed from the aqueous inkjet ink, which was separated in the wet disintegration step described above, is removed from the mixture. This can be done by selectively adsorbing the fragments of the aqueous inkjet ink layer onto bubbles (flotation method) or by repeatedly filtering and washing using a mesh or the like (washing method). Either method may be adopted. In the present invention, the resin particles (A1) contained in the pretreatment liquid have suitable acid values ​​and SP values, and are easily adsorbed together with the aqueous inkjet ink onto bubbles (and the deinking agent present at their interface). Therefore, from the viewpoint of obtaining highly pure deinked pulp and recycled paper, the flotation method is preferred.

[0226] When employing the flotation method, conventionally known equipment such as flotators, extractors, and multiwashers can be used without restriction. Furthermore, the temperature of the mixture during flotation is preferably 15 to 50°C, and particularly preferably 25 to 50°C. In addition, the pulp concentration in the mixture during flotation is preferably 0.5 to 2% by mass, and particularly preferably 0.6 to 1.5% by mass.

[0227] Furthermore, after the wet disintegration step and before the aqueous inkjet ink layer removal step, a dilution step and / or a dewatering step may be performed to adjust the solid content concentration of the mixture. Also, a filtration step may be performed to separate and remove coarse matter from the mixture. In addition, before the aqueous inkjet ink layer removal step, the amount of components in the mixture (basic material, bleaching agent, bleaching aid, disintegration accelerator, deinking agent, defoaming agent, etc. as described above) may be increased. In addition, components such as foaming agents may be added.

[0228] <Method for separating layers of water-based inkjet ink from printed materials onto a plastic substrate> On the other hand, as a method for separating the aqueous inkjet ink layer from a printed material (or a laminate obtained by laminating the printed material) on a plastic substrate manufactured using the pretreatment solution and aqueous inkjet ink of the present invention, a method including an immersion step in a basic solution can be used. In this immersion step, the printed material (or laminate) is immersed in a basic solution to separate the layer formed from the aqueous inkjet ink from the plastic substrate. The basic solution includes at least a basic material and a liquid medium (preferably an aqueous medium). In addition, to improve separation efficiency, the printed material (or laminate) that has been crushed or pulverized in advance may be used.

[0229] As the basic material mentioned above, for example, alkali metal hydroxides can be used, and sodium hydroxide or potassium hydroxide are preferably used from the viewpoint of basicity strength (high pKb value), high solubility in aqueous media, bonding ability with acid groups in resin particles (A1) contained in the pretreatment layer, and availability. The amount is preferably 0.2 to 15% by mass of the total amount of basic solution, more preferably 0.5 to 12% by mass, and particularly preferably 1 to 10% by mass. By having the concentration within the above range, the basic solution can maintain sufficient basicity for separation. Furthermore, even without immersion of the basic solution inside the plastic substrate, sufficient separation can be achieved, for example, by penetration from the surface or edges of the printed material.

[0230] The temperature of the mixture during the immersion step in the basic solution is preferably 20 to 120°C, more preferably 25 to 110°C, even more preferably 28 to 90°C, and particularly preferably 30 to 80°C. Furthermore, the duration of the immersion step carried out within the above preferred temperature range is preferably 1 minute to 24 hours, even more preferably 1 minute to 12 hours, and particularly preferably 1 minute to 6 hours.

[0231] Furthermore, it is preferable to perform the separation while stirring during immersion. For example, when stirring with a rotating blade, the rotation speed is preferably 80 to 250 rpm, and more preferably 80 to 200 rpm.

[0232] Furthermore, the amount of basic solution used is preferably 100 to 1,000,000 times the mass of the printed material (or laminated material). To reduce the amount of basic solution used, a separation device capable of circulating the basic solution may be used. [Examples]

[0233] Next, the present invention will be described in more detail with reference to examples and comparative examples. In the following description, "parts" and "%" refer to mass unless otherwise specified.

[0234] <Manufacturing Example 1: Manufacturing of (meth)acrylic resin particles 1 (Ac1)> In a reaction vessel equipped with a gas inlet pipe, thermometer, condenser, and stirrer, 124 parts of deionized water and 1.2 parts of polyoxyethylene lauryl ether sodium sulfate (Kao Corporation's Latemul E-150) as an emulsifier were charged. Meanwhile, in a separate mixing vessel equipped with a stirrer, 0.2 parts of acrylic acid, 29.8 parts of n-butyl acrylate, 60 parts of methyl methacrylate, 10 parts of butyl methacrylate, 64 parts of deionized water, and 0.8 parts of polyoxyethylene lauryl ether sodium sulfate (Kao Corporation's Latemul E-150) as an emulsifier were sequentially added, and then the mixture was stirred to form an emulsion.

[0235] Eight parts of the above emulsion were taken and added to the reaction vessel. After addition, the internal temperature was raised to 80°C and the inside of the vessel was thoroughly purged with nitrogen. Then, four parts of a 5% aqueous solution of potassium persulfate and eight parts of a 1% aqueous solution of anhydrous sodium bisulfite were added to start the polymerization reaction. After the polymerization reaction started, while maintaining the internal temperature at 80°C, the remaining emulsion prepared above, along with 1.2 parts of a 5% aqueous solution of potassium persulfate and 2.5 parts of a 1% aqueous solution of anhydrous sodium bisulfite were added dropwise over 1.5 hours. After the dropwise addition was completed, stirring was continued for another 2 hours, and then the mixture was cooled until the internal temperature was below 30°C. Dimethylaminoethanol was then added to adjust the pH of the contents to 8.5, and then deionized water was added to adjust the solid content to 30%, resulting in an acid value of 1.6 (mgKOH / g), a Tg of 30.5 (°C), and an SP value of 9.3 (cal / cm²). 3 ) 1 / 2 An aqueous dispersion of (meth)acrylic resin particles 1 (Ac1) (30% solid content) was obtained.

[0236] <Manufacturing Examples 2-52: Manufacturing of (meth)acrylic resin particles 2-52 (Ac2-52)> Aqueous dispersions of (meth)acrylic resin particles 2-52 (Ac2-52), each with a solid content of 30%, were prepared using the same procedure as for (meth)acrylic resin particle 1, except that the type and amount of ethylenically unsaturated monomer used in the preparation of the emulsion, and the type of emulsifier added to the reaction vessel and mixing vessel were changed as shown in Table 1.

[0237] [Table 1]

[0238] [Table 1]

[0239] [Table 1]

[0240] Table 1 also lists the SP value, acid value, and glass transition temperature for the manufactured (meth)acrylic resin particles 1 to 52. The abbreviations listed in Table 1 represent the following materials, respectively. AA: Acrylic acid (SP value: 11.1 (cal / cm³) 3 ) 1 / 2 ) • MAA: Methacrylic acid (SP value: 10.7 (cal / cm³) 3 ) 1 / 2 ) HOA-MS: 2-Acryloyloxyethyl succinate (SP value: 11.9 (cal / cm³) 3 ) 1 / 2 ) SEMA: 2-methacryloyloxyethanesulfonic acid (SP value: 10.7 (cal / cm³) 3 ) 1 / 2 ) • St-SO3Na: Sodium styrene sulfonate (SP value: 10.8 (cal / cm³) 3 ) 1 / 2 ) • EA: Ethyl acrylate (SP value: 9.4 (cal / cm³) 3 ) 1 / 2 ) BA: Butyl acrylate (SP value: 9.2 (cal / cm) 3 ) 1 / 2 ) 2-EHA: 2-ethylhexyl acrylate (SP value: 8.9 (cal / cm³) 3 ) 1 / 2 ) LA: Lauryl acrylate (SP value: 8.9 (cal / cm) 3 ) 1 / 2 ) STA: Stearyl acrylate (SP value: 8.8 (cal / cm³) 3 ) 1 / 2 ) • HEA: 2-hydroxyethyl acrylate (SP value 12.9 (cal / cm³) 3 ) 1 / 2 ) MMA: Methyl methacrylate (SP value: 9.4 (cal / cm³) 3 ) 1 / 2 ) ·BMA: Butyl methacrylate (SP value: 9.2 (cal / cm 3 ) 1 / 2 ) ·StMA: Stearyl methacrylate (SP value: 8.8 (cal / cm 3 ) 1 / 2 ) ·dMAEMA: Dimethylaminoethyl methacrylate (SP value: 9.2 (cal / cm 3 ) 1 / 2 ) ·BzMA: Benzyl methacrylate (SP value: 10.3 (cal / cm 3 ) 1 / 2 ) ·GlyMA: Glycerol monomethacrylate (SP value: 14.5 (cal / cm 3 ) 1 / 2 ) ·St: Styrene (SP value: 9.2 (cal / cm 3 ) 1 / 2 ) ·EOEOEA: Ethoxyethoxyethyl acrylate (EO = 2 mol, SP value 9.4 (cal / cm 3 ) 1 / 2 ) ·MPEG(550)MA: Methoxypolyethylene glycol methacrylate (EO ≒ 12 mol, SP value 9.4 (cal / cm 3 ) 1 / 2 ) · Latemul E-150: Sodium polyoxyethylene lauryl ether sulfate manufactured by Kao Corporation m · Aqualon KH-10: Ether sulfate ester salt manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

[0241] <Production Example 53: Production of Urethane Urea Resin Particles 1 (Ur1)> In a reaction vessel equipped with a gas inlet tube, thermometer, condenser, and stirrer, 72 parts of pre-dehydrated polyester polyol (Kuraray Co., Ltd. "P-2010", hydroxyl value: 56 (mgKOH / g)), 3.4 parts of dimethylolpropionic acid, 59.9 parts of methyl ethyl ketone, and 20 parts of isophorone diisocyanate were charged. The internal temperature was then raised to 80°C and the reaction was carried out for 4 hours to obtain a mixed solution containing a urethane prepolymer with terminal isocyanate groups. After cooling this mixed solution to 40°C, 20 parts of methyl ethyl ketone were added, followed by 2.2 parts of dimethylaminoethanol to neutralize the acid groups.

[0242] Next, while stirring the mixed solution containing the above-mentioned terminal isocyanate group urethane prepolymer, 209.4 parts of deionized water were gradually added to emulsify the urethane prepolymer. Then, an aqueous solution of isophorone diamine (4.6 parts of isophorone diamine dissolved in a mixed solution of 16.4 parts of isopropyl alcohol and 16.4 parts of deionized water) was gradually added to the resulting emulsion to carry out the chain extension reaction. Finally, methyl ethyl ketone and isopropyl alcohol were removed under reduced pressure, and deionized water was added to adjust the solid content to 30%, resulting in an acid value of 14.2 (mgKOH / g) and an SP value of 11.1 (cal / cm³). 3 ) 1 / 2 An aqueous dispersion of urethane urea resin particles 1 (Ur1) (solid content 30%) was obtained.

[0243] <Manufacturing Examples 54-63: Manufacturing of Urethane Urea Resin Particles 2-11 (Ur2-11)> Aqueous dispersions of urethane urea resin particles 2-11 (Ur2-11), each with a solid content of 30%, were prepared using the same procedure as for urethane urea resin particle 1 (Ur1), except that the types and amounts of polyol (u1) and polyisocyanate (u2) added to the reaction vessel, and the chain extender (u3) added during the chain extension reaction were changed as shown in Table 2.

[0244] <Manufacturing Example 64: Manufacturing Example of Urethane-(Meth)acrylic Resin Particles 1 (UrAc1)> In a reaction vessel equipped with a gas inlet tube, thermometer, condenser, and stirrer, 28.4 parts methyl methacrylate, 66.4 parts n-butyl methacrylate, and 26.4 parts methyl ethyl ketone were charged, and the internal temperature was raised to 50°C. Further, 5.2 parts 1-thioglycerol was added, and the mixture was heated to 90°C. Then, a solution of 0.1 parts azoisobisbutyronitrile dissolved in 18.7 parts methyl ethyl ketone was added dropwise to the reaction vessel over 5 hours, and the reaction was allowed to continue for another hour after the dropwise addition was complete. After cooling the reaction vessel to below 30°C, methyl ethyl ketone was added to adjust the solid content to 60%, thereby obtaining a methacrylic resin solution with a diol terminus (diol-terminated methacrylic resin 1) with a number-average molecular weight of approximately 2,000.

[0245] Next, in a separate reaction vessel equipped with a gas inlet tube, thermometer, condenser, and stirrer, 65.1 parts of pre-dehydrated polyester polyol (Toyokuni Chemical Co., Ltd. "HS2H-201AP", hydroxyl value: 56 (mgKOH / g)), 12.0 parts (7.2 parts in terms of solids) of the methacrylic resin solution having a diol terminus prepared above (diol-terminated methacrylic resin 1, solids content 60%), 5.1 parts of dimethylolpropionic acid, 61.6 parts of methyl ethyl ketone, and 20.1 parts of isophorone diisocyanate were charged. After that, the temperature was raised to 80°C and the mixture was reacted for 4 hours to obtain a terminal isocyanate group urethane prepolymer solution. After cooling this solution to below 40°C, 20.5 parts of methyl ethyl ketone were added to dilute it, and then 3.4 parts of dimethylaminoethanol were added to neutralize the acid groups in the prepolymer molecule.

[0246] Subsequently, 209.4 parts of deionized water were gradually added to the stirred terminal isocyanate group urethane prepolymer solution to emulsify it. To this emulsion, an aqueous solution of isophorone diamine (2.5 parts of isophorone diamine dissolved in a mixture of 15.3 parts of isopropyl alcohol and 15.3 parts of deionized water) was gradually added to induce a chain extension reaction. Then, methyl ethyl ketone and isopropyl alcohol were removed under reduced pressure, and the solid content was further adjusted to 30% with deionized water, resulting in an acid value of 21.3 (mgKOH / g) and an SP value of 11.7 (cal / cm³). 3 ) 1 / 2 An aqueous dispersion of urethane-(meth)acrylic resin particles 1 (UrAc1) (solid content 30%) was obtained.

[0247] [Table 2]

[0248] Table 2 also lists the SP values ​​and acid values ​​of the manufactured urethane urea resin particles 1-11 and urethane-(meth)acrylic resin particle 1. Furthermore, the blending amount of diol-terminated methacrylic resin 1 in manufacturing example 64 is calculated on a solids basis. Details of the product names and abbreviations listed in Table 2 are as follows. P-2010: Kuraray polyester polyol (3-methyl-1,5-pentanediol / adipic acid; number of functional groups: 2, hydroxyl value: 56 mgKOH / g, SP value: 10.9 (cal / cm³) 3 ) 1 / 2 ) • HS2H-201AP: Toyokuni Chemical Co., Ltd. Polyester polyol (1,6-Hexanediol / Adipic acid; Number of functional groups: 2, Hydroxyl value: 56 mgKOH / g, SP value: 10.9 (cal / cm³) 3 ) 1 / 2 ) UH200: Ube Industries-produced polycarbonate polyol (1,6-hexanediol carbonate; number of functional groups: 2, hydroxyl value: 56 mgKOH / g, SP value: 10.8 (cal / cm³) 3 ) 1 / 2 ) PEG2000: NOF Corporation polyethylene glycol (Functional group count: 2, Hydroxyl value: 56 mgKOH / g, SP value: 10.8 (cal / cm³) 3 ) 1 / 2 ) DMPA: Dimethylolpropionic acid (SP value: 16.1 (cal / cm³) 3 ) 1 / 2 ) IPDI: Isophorone diisocyanate (SP value: 10.9 (cal / cm³) 3 ) 1 / 2 ) m-TMXDI: m-tetramethylxylylene diisocyanate (SP value: 11.0 (cal / cm³) 3 ) 1 / 2 ) • IPDA: Isophorone diamine (SP value: 7.7 (cal / cm³) 3 ) 1 / 2 ) m-TMXDA: m-tetramethylxylenediamine (SP value: 8.3 (cal / cm³) 3 ) 1 / 2 ) AEA: N-(2-aminoethyl)ethanolamine (SP value: 11.9 (cal / cm³) 3 ) 1 / 2 )

[0249] <Manufacturing Example 65: Manufacturing of Polyester Resin Particles 1 (PEs1)> 15.5 parts of bisphenol A propylene oxide adduct (approximately 2 moles added), 57 parts of bisphenol A ethylene oxide adduct (approximately 2 moles added), 26 parts of fumaric acid, and 0.5 parts of 2-ethylhexanoate tin were charged into the reaction vessel. After purging the vessel with nitrogen, the internal temperature was raised to 235°C and the reaction was allowed to proceed for 1 hour. Next, the internal temperature was cooled to 210°C, and 1.5 parts of fumaric acid and 0.005 parts of 4-tert-butylcatechol (polymerization inhibitor) were added, and the reaction was allowed to proceed for a further 30 minutes. After that, the pressure in the reaction vessel was reduced and maintained at 8.3 kPa for 1 hour to obtain polyester resin 1. The acid value of polyester resin 1, measured by the method described above, was 28.4 (mgKOH / g), and the SP value of polyester resin 1, calculated from the SP values ​​of the above raw material monomers used, was 12.6 (cal / cm²). 3 ) 1 / 2 That was the case.

[0250] 100 parts of the polyester resin obtained above were dissolved in an equal volume of methyl ethyl ketone, and then a 6 mol / L sodium hydroxide aqueous solution was added in an amount equal to 1 / 4 times the acid value of the polyester resin 1 (i.e., 28.4 × 1 / 4 = 7.1 parts). Then, while stirring the contents, 300 parts of deionized water were added little by little, and the methyl ethyl ketone was removed under reduced pressure. Further deionized water was added to adjust the solid content to 30%, thereby obtaining an aqueous dispersion of polyester resin particles 1 (PEs1) (solid content 30%).

[0251] <Manufacturing Examples 66-73: Manufacturing of Polyester Resin Particles 2-9 (PEs2-9)> Aqueous dispersions of polyester resin particles 2-9 (PEs2-9), each with a solid content of 30%, were prepared using the same procedure as for polyester resin particle 1 (PEs1), except that the types and amounts of polyol (e1) and polycarboxylic acid (e2) added to the reaction vessel were changed as shown in Table 3.

[0252] [Table 3]

[0253] Table 3 also lists the SP values ​​and acid values ​​of the manufactured polyester resin particles 1-9. Details of the product names and abbreviations listed in Table 3 are as follows. • BisA-(PO)2: Bisphenol A propylene oxide adduct (Number of moles added ≈ 2, SP value: 11.3 (cal / cm³) 3 ) 1 / 2 ) • BisA-(EO)2: Bisphenol A ethylene oxide adduct (Number of moles added ≈ 2, SP value: 11.8 (cal / cm³) 3 ) 1 / 2 ) • 1,3-PD: 1,3-propanediol (SP value: 13.7 (cal / cm³) 3 ) 1 / 2 ) TPA: Terephthalic acid (SP value: 13.8 (cal / cm³) 3 ) 1 / 2 ) • FA: Fumaric acid (SP value: 13.5 (cal / cm³) 3 ) 1 / 2 ) S-IPA: 5-sulfisophthalic acid (SP value: 14.7 (cal / cm³) 3 ) 1 / 2 ) • TOA: Trimellitus (SP value: 15.2 (cal / cm³) 3 ) 1 / 2 )

[0254] <Manufacturing Example 74: Manufacturing Example of Pretreatment Solution 1> The following materials were placed in a mixing vessel equipped with a stirrer and mixed at room temperature (25°C) for 1 hour. The mixture was then heated to 50°C and mixed for another 1 hour. Afterward, the mixture was cooled to room temperature and filtered through a 100 μm pore size nylon mesh to produce pretreatment solution 1. Details of the materials used will be described later. • Resin particles 1 (Ac1) 25.0 parts (7.5 parts as solid content) • Hi-Tec E-6400 2.9 parts (As solid content: 1.0 part) Calcium formate 3.0 parts Calcium lactate 2.0 parts 2-propanol 5.0 parts • Surfinol 440 1.0 part 1.0 part of a 1% aqueous solution of 1,2-benzisothiazolin-3-one • Ion-exchanged water 60.1 parts

[0255] <Manufacturing Examples 75-219: Manufacturing Examples of Pretreatment Solutions 2-146> Except for using the materials listed in Table 4, pretreatment solutions 2 to 146 were prepared in the same manner as pretreatment solution 1.

[0256] [Table 4]

[0257] [Table 4]

[0258] [Table 4]

[0259] [Table 4]

[0260] [Table 4]

[0261] [Table 4]

[0262] [Table 4]

[0263] [Table 4]

[0264] [Table 4]

[0265] [Table 4]

[0266] [Table 4]

[0267] [Table 4]

[0268] [Table 4]

[0269] [Table 4]

[0270] Further details regarding the product names and abbreviations listed in Table 4 are as follows: • Hi-Tec E-6400: Non-chlorinated polyolefin resin particles (35% solid content) manufactured by Toho Chemical Industry Co., Ltd. • Arrowbase SB-1200: Non-chlorinated polyolefin resin particles manufactured by Unitika Corporation (solid content 25%) • Adekanol UH526: Hydrophobic modified water-soluble urethane resin manufactured by ADEKA Corporation. IPA: 2-propanol (SP value: 11.6 (cal / cm³) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 83°C) • EG: 1,2-Ethanediol (SP value: 14.8 (cal / cm³) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 198°C) • 1,2-PD: 1,2-propanediol (SP value: 13.5 (cal / cm³) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 188°C) • 1,3-BD: 1,3-butanediol (SP value: 12.8 (cal / cm) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 208°C) • 1,2-HD: 1,2-Hexanediol (SP value: 11.8 (cal / cm²) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 224°C) MP: Propylene glycol monomethyl ether (SP value: 11.3 (cal / cm³) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 121°C) • MB: 3-Methoxy-1-butanol (SP value: 10.9 (cal / cm³) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 158°C) MMB: 3-methyl-3-methoxy-1-butanol (SP value: 10.5 (cal / cm³) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 174°C) • DEDG: Diethylene glycol diethyl ether (SP value: 8.0 (cal / cm³) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 189°C) Gly: Glycerin (SP value: 16.4 (cal / cm³) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 290°C) · 2-Py: 2-pyrrolidone (SP value: 11.2 (cal / cm³) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 245°C) TEA: Triethanolamine (SP value: 13.7 (cal / cm³) 3 ) 1 / 2 (Boiling point at 1 atmosphere: 335°C) • Surfinol 104: Acetylenediol-based surfactant manufactured by Nisshin Chemical Industry Co., Ltd. (SP value: 10.4 (cal / cm³) 3) 1 / 2 ) • Surfinol 440: Acetylenediol-based surfactant manufactured by Nisshin Chemical Industry Co., Ltd. (SP value: 10.1 (cal / cm³) 3 ) 1 / 2 ) • Surfinol 465: Acetylenediol-based surfactant manufactured by Nisshin Chemical Industry Co., Ltd. (SP value: 9.8 (cal / cm³) 3 ) 1 / 2 ) • Surfinol 485: Acetylenediol-based surfactant manufactured by Nisshin Chemical Industry Co., Ltd. (SP value: 9.6 (cal / cm³) 3 ) 1 / 2 ) • POAE compound 1: In the above general formula 6, R 6 = Compound with a lauryl group, m=5, n=0 (SP value = 9.6 (cal / cm²) 3 ) 1 / 2 ) • POAE compound 2: In the above general formula 6, R 6 = Compound with a lauryl group, m=50, n=0 (SP value=9.4(cal / cm) 3 ) 1 / 2 ) • POAE compound 3: In the above general formula 6, R 6 = Compound with a lauryl group, m=100, n=0 (SP value=9.4(cal / cm) 3 ) 1 / 2 ) • POAE compound 4: In the above general formula 6, R 6 = A compound with a stearyl group, m=6, n=0 (SP value = 9.4 (cal / cm²) 3 ) 1 / 2 ) • POAE compound 5: In the above general formula 6, R 6 = A compound with a stearyl group, m=40, n=0 (SP value = 9.4 (cal / cm²) 3 ) 1 / 2 ) • POAE compound 6: In the above general formula 6, R 6 Compounds with a 2-ethylhexyl group, m=4, n=0 (SP value = 9.8 (cal / cm²) 3 ) 1 / 2 ) • POAE compound 7: In the above general formula 6, R 6 = Compound with a behenyl group, m=5, n=0 (SP value = 9.3 (cal / cm²) 3 ) 1 / 2 ) • POAA compound 1: In the above general formula 7, R 7 = Compound with a lauryl group, p=3, q=0, r=3, s=0 (SP value = 10.0 (cal / cm²) 3 ) 1 / 2 ) • POAA compound 2: In the above general formula 7, R 7 = A compound with a stearyl group, p=5, q=0, r=5, and s=0 (SP value = 9.7 (cal / cm²) 3 ) 1 / 2 ) • Siloxane compound 1: In the above general formula 8, t=2, u=1, a=3, b=3, R 81 = Ethylene group (-CH2CH2-), R 82 =Methyl group compound (SP value = 8.1 (cal / cm) 3 ) 1 / 2 ) • Siloxane compound 2: In the above general formula 8, t=1, u=0, a=8, b=3, R 81 = Ethylene group (-CH2CH2-), R 82 = A compound containing hydrogen atoms (SP value = 9.0 (cal / cm³) 3 ) 1 / 2 ) • CarbodiLite E-05: Polycarbodiimide resin (40% solids content) manufactured by Nisshinbo Chemical Co., Ltd. BITaq: 1% aqueous solution of 1,2-benzisothiazolin-3-one

[0271] <Manufacturing of water-based inkjet inks> (Manufacturing Example 220: Manufacturing of Black Pigment Dispersion) Fifteen parts of carbon black (PrinteX85, manufactured by Orion Engineered Carbons), three parts of styrene-acrylic resin (a random polymer of styrene / acrylic acid / behenyl acrylate = 45 / 30 / 25 (mass ratio), with all acid groups neutralized by dimethylaminoethanol, acid value 230 mg KOH / g, weight-average molecular weight 20,000), and 82 parts of water were added to a mixing vessel equipped with a stirrer and premixed for one hour. Subsequently, the mixture was circulated and dispersed using a 0.6 L volume "DinoMill" container (manufactured by Synmaru Enterprises) filled with 1800 g of 0.5 mm diameter zirconia beads until the 50% diameter of the carbon black reached approximately 100 nm, thereby producing a black pigment dispersion. The above 50% diameter was measured using the same apparatus and method as the 50% diameter of the resin particles (A1) described above.

[0272] (Manufacturing examples 221-223: Manufacturing of cyan pigment dispersion, magenta pigment dispersion, and yellow pigment dispersion) Cyanide pigment dispersions, magenta pigment dispersions, and yellow pigment dispersions were manufactured using the same raw materials and methods as the black pigment dispersion described above, except that the pigments listed below were used as pigments and each was subjected to circulating dispersion until it reached a diameter of 50% as shown below. • Cyan pigment dispersion: LIONOL BLUE 7358G (CI Pigment Blue 15:3) manufactured by Toyo Color Co., Ltd., 50% diameter = 150nm • Magenta pigment dispersion: DIC FASTGEN SUPER MAGENTA RG (CI Pigment Red 122), 50% diameter = 150 nm • Yellow pigment dispersion: LIONOL YELLOW TT1405G (CI Pigment Yellow 14) manufactured by Toyo Color, 50% diameter = 150nm

[0273] (Manufacturing example 224: Manufacturing of black ink 1 (K1)) 33.3 parts of black pigment dispersion, 13.4 parts of aqueous solution of binder resin 28 (30% solids) prepared by the method described in the examples of Japanese Patent Publication No. 2020-180178, 20 parts of 1,2-propanediol, 4 parts of propylene glycol monomethyl ether, 1.5 parts of TEGO Wet 280 (polyether-modified siloxane surfactant manufactured by Evonik), and 1 part of Surfinol 465 (acetylenediol surfactant manufactured by Nisshin Chemical Industry Co., Ltd.) were sequentially added to a mixing container. Then, water was added so that the total amount of added material was 100 parts, and the mixture was stirred with a stirrer until it was thoroughly homogenized. After that, the mixture was filtered through a membrane filter with a pore size of 1 μm to remove coarse particles that could cause printhead clogging, and black ink 1 (K1) was prepared.

[0274] (Manufacturing examples 225-227: Manufacturing of cyan ink 1 (C1), magenta ink 1 (M1), and yellow ink 1 (Y1)) Cyan ink 1 (C1), magenta ink 1 (M1), and yellow ink 1 (Y1) were obtained using the same method as for black ink 1, except that cyan pigment dispersion, magenta pigment dispersion, and yellow pigment dispersion were used as pigment dispersions, respectively. These four types of aqueous inkjet inks, K1, C1, M1, and Y1, were then used as aqueous inkjet ink set 1 for the evaluation described below.

[0275] <Example of substrate preparation with pretreatment solution applied> Using an OSG System Products 250-OSP-02 non-wire bar coater, the pretreatment solution prepared above was applied to the substrate shown below to a wet film thickness of 2.0 ± 0.2 μm. After application, the substrate was placed in a 70°C air oven and dried for 2 minutes to produce a substrate treated with the pretreatment solution.

[0276] (Substrates used for evaluation) • OPP: Biaxially oriented polypropylene film "OPU-1" (thickness 20 μm) manufactured by Mitsui Chemicals Tohcello Co., Ltd. • PET: Futamura Co., Ltd. polyethylene terephthalate film "FE2001" (thickness 12μm) • Coated paper: Oji Paper Co., Ltd.'s coated paper "OK ​​Topcoat+" (basis weight 104.7g / m²) 2 )

[0277] <Examples of printed materials> Four Kyocera inkjet heads "KJ4B-1200" (design resolution 1,200 dpi, nozzle diameter 20 μm) were installed on top of a conveyor capable of transporting substrates. The aqueous inkjet ink set 1 manufactured above was filled into the inkjet heads in the order of K1, C1, M1, and Y1, starting from the inkjet head on the upstream side in the substrate transport direction. Next, the substrates that had been treated with the pre-processing liquid prepared above were fixed onto the conveyor, and the conveyor was driven at a constant speed. As the substrate passed through the inkjet head installation area, the aqueous inkjet inks were ejected at a drop volume of 2 pL each to print an image. After that, the printed material was immediately placed in a 70°C air oven and dried for 3 minutes to produce a printed material.

[0278] Two types of printable images were prepared: one consisting of adjacent 5cm x 10cm solid patches with 100% print coverage in CMYK order (hereinafter referred to as "solid patch images"), and another consisting of four-color (CMYK) images with a continuous variation in total print coverage (sum of print coverage for each color) from 40% to 320% (hereinafter referred to as "gradient images"; the print coverage for each color is the same at each total print coverage). Printed materials were then produced using both types of images.

[0279] [Examples 1-131, Comparative Examples 1-15] For each of the pretreatment solutions prepared as described above, printed materials were produced in combination with water-based inkjet ink set 1. The following evaluations were performed using these printed materials, or the pretreatment solutions themselves. The evaluation results are shown in Table 5.

[0280] <Evaluation 1: Evaluation of color bleeding> Based on the method described above, printed materials were produced under a conveyor drive speed of 75 m / min. Of the obtained printed materials, those with gradient images printed on an OPP film substrate were used, and their dot shapes were observed at 200x magnification using an optical microscope to evaluate image quality (color bleeding). The evaluation criteria were as follows, with ◎, ○, and △ indicating materials suitable for practical use. ◎: No dot merging or dot shape inconsistencies were observed in areas with a total print density of 240%. ○: In areas with a total print density of 240%, dot merging and dot shape unevenness were observed, but in areas with a total print density of 160%, dot merging and dot shape unevenness were not observed. △: In areas with a total print density of 160%, dot merging and dot shape unevenness were observed, but in areas with a total print density of 120%, dot merging and dot shape unevenness were not observed. ×: In areas where the total print density was 120%, dots were observed to merge or have uneven shapes.

[0281] <Rating 2: Evaluation of being completely filled> Based on the above method, printed materials were produced under conveyor drive speed conditions of 25 m / min, 50 m / min, or 75 m / min. Of the obtained printed materials, those with solid patch images printed on an OPP film substrate were evaluated for image quality (solid coverage) by visually observing the degree of white gaps after bonding the non-printed side of the printed material to a white backing sheet. The evaluation criteria were as follows, with ◎, ○, and △ indicating usable materials. ◎: No white spots were observed in the printed material printed at 75 m / min. ○: White spots were observed in printed materials printed at 75 m / min, but no white spots were observed in printed materials printed at 50 m / min. △: White areas were observed in prints printed at 50 m / min, but no white areas were observed in prints printed at 25 m / min. ×: White areas were observed in the printed material printed at 25 m / min.

[0282] <Evaluation 3: Evaluation of blocking resistance> Based on the method described above, printed materials were produced under a conveyor drive speed of 50 m / min. From the obtained printed materials, the solid patch image printed on OPP film substrates and PET film substrates were cut out in 4cm x 4cm squares from the black ink 1 printed area. Then, the printed side of the cut-out black ink 1 printed area was superimposed with the non-printed side (back side) of the same film used for printing. A blocking test was then performed using a constant-load permanent strain tester (manufactured by Tester Sangyo Co., Ltd.). The environmental conditions for the blocking test were a load of 10 kg / cm². 2 The test was conducted at a temperature of 35°C, humidity of 50%RH, and standing for 24 hours. After 24 hours, the stacked films were instantly peeled off while maintaining a 90-degree angle, and the printing surface after peeling was visually inspected to evaluate blocking resistance. The evaluation criteria were as follows, with ◎, ○, and △ indicating usable in practice. ◎: There was absolutely no layer removal of the water-based inkjet ink from the non-printable film, and there was no peeling resistance. ○: There was no removal of the water-based inkjet ink layer from the non-printable film, but there was slight resistance during peeling. △: The amount of water-based inkjet ink covering the non-printable film was 30% or less of the total overlapping area. ×: The layer of water-based inkjet ink covering the non-printable film exceeded 30% of the total overlapping area.

[0283] <Evaluation 4-1: Evaluation of the separation properties of layers formed from water-based inkjet ink on a plastic substrate> Based on the above method, printed materials were produced under a conveyor drive speed of 50 m / min. From the obtained printed materials, a solid patch image printed on a PET film substrate was cut out in a 4 cm x 4 cm square from the black ink 1 printed area. Next, the cut-out printed material was immersed in 50 g of a 2 mass% sodium hydroxide aqueous solution, heated to 70°C, and stirred for a predetermined time. After that, the printed material was removed from the sodium hydroxide aqueous solution, washed with water, and dried. The degree to which the aqueous inkjet ink layer separated from the PET film substrate was visually confirmed to evaluate the separation performance of the layer formed from aqueous inkjet ink on the plastic substrate. The evaluation criteria were as follows, with ◎, ○, and △ indicating that the material was usable in practice. ◎: After stirring for 20 minutes, the layer formed from the water-based inkjet ink was 100% separated from the PET film substrate. ○: After stirring for 60 minutes, the layer formed from the water-based inkjet ink was 100% separated from the PET film substrate. △: After stirring for 180 minutes, the layer formed from the water-based inkjet ink separated from the PET film substrate by more than 80%. ×: Even after stirring for 180 minutes, the separation rate of the layer formed from the water-based inkjet ink from the PET film substrate was less than 80%.

[0284] <Evaluation 4-2: Evaluation of the separation properties of layers formed from water-based inkjet inks on paper substrates> Based on the above method, printed materials were produced under a conveyor drive speed of 50 m / min. From the obtained printed materials, solid patch image prints on high-quality paper substrates were cut into 3 cm x 3 cm squares. 400 pieces of these cut-out prints were prepared and all were placed in a mixing container equipped with a stirrer. Then, 1500 g of 0.02 mass% sodium hydroxide aqueous solution was added, and the mixture was heated to 45°C while stirring, and stirring was continued at the same temperature for 20 minutes (wet disintegration process). Next, 4000 g of water and 5 g of 1.5 mass% aqueous solution of DI-7020 (manufactured by Kao Corporation) as a deinking agent were added to the above mixture, and the mixture was stirred for 10 minutes while supplying air and scraping off floss (bubbles) as needed to perform the aqueous inkjet ink layer removal process (flotation method). Subsequently, the separation properties of the layer formed from water-based inkjet ink from the paper substrate were evaluated by visually observing the color (degree of coloring) of the residue (pulp mat) obtained by suction filtration using a Buchner funnel. The evaluation criteria were as follows, with ◎, ○, and △ indicating that the product was usable in practice. ◎: The color (degree of coloring) was weaker than that of the pulp mat produced in Example 13. ○: The color (degree of coloring) was similar to that of the pulp mat produced in Example 13. △: The color (degree of coloring) was similar to that of the pulp mat produced in Example 1. ×: The color (degree of coloring) was stronger than that of the pulp mat produced in Example 1.

[0285] <Evaluation 5: Evaluation of storage stability of pretreatment solution> The 50% diameter of the pretreatment solution prepared as described above was measured using a Microtrac-Bell Nanotrac UPA-EX150. The pretreatment solution was then sealed in a container and stored in a constant temperature chamber set to 70°C. The sealed container was removed weekly after the start of storage, and the 50% diameter was measured again using the same equipment and conditions as at the start of the evaluation. The storage stability of the pretreatment solution was evaluated by calculating the percentage change in the 50% diameter before and after storage. The evaluation criteria were as follows, with ◎, ○, and △ indicating that the solution was usable for practical purposes. ◎: The 50% diameter change rate after 4 weeks of storage was less than ±10%. ○: The 50% diameter change rate after 3 weeks of storage was less than ±10%, but the 50% diameter change rate after 4 weeks of storage was ±10% or more. △: The 50% diameter change rate after 2 weeks of storage was less than ±10%, but the 50% diameter change rate after 3 weeks of storage was ±10% or more. ×: The 50% diameter change rate after 2 weeks of storage was ±10% or more.

[0286] [Table 5]

[0287] [Table 5]

[0288] [Table 5]

[0289] [Table 5]

[0290] The pretreatment solutions used in Examples 1 to 131 contained resin particles (A) having a specific SP value and acid value, calcium ions, carboxylate ions, and a water-soluble organic solvent and / or surfactant having a specific (mixed) SP value, with a defined ratio of the amount of resin particles (A) to the millimolar amount of calcium ions. Good results were obtained in all evaluated items.

[0291] Comparing Examples 81, 84-86, and 100, it can be confirmed that the results of the color mixing bleeding evaluation, solid filling evaluation, and blocking evaluation were improved in Examples 81, 84-86, and 86, which used pretreatment solutions 86 and 89-91 containing two or more carboxylate ions, compared to Example 100, which used pretreatment solution 105 containing only formate ions as carboxylate ions.

[0292] Furthermore, comparing Examples 104, 108, and 109, which contain 5% by mass of a water-soluble organic solvent with a boiling point of 75-200°C at 1 atmosphere, differing only in the type of water-soluble organic solvent, Example 104 showed a separation performance to the plastic substrate at a ○ level and storage stability of the pretreatment solution at a △ level, while Examples 108 and 109 both achieved an ◎ level in these evaluation results. In the pretreatment solution 114 used in Example 104, the difference between the SP value of the mixed water-soluble organic solvent and surfactant and the SP value of the resin particles (A1) was 3.6, whereas in the pretreatment solutions 118 and 119 used in Examples 108 and 109, the above difference was 1.7 and 1.4, respectively, indicating that the above difference contributes to the improvement of separation performance and storage stability.

[0293] On the other hand, the pretreatment solutions 53 to 56 used in Comparative Examples 1 to 4 each had a resin particle SP value of 9.0 (cal / cm²). 3 ) 1 / 2 For those with a resin particle SP value of less than 14.0 (cal / cm³), the SP value of the resin particles is 14.0 (cal / cm³). 3 ) 1 / 2 The resin particles are larger than 60 mgKOH / g, have an acid value of less than 1 mgKOH / g (zero), and have an acid value of more than 60 mgKOH / g. As a result of the evaluation, two or more items of blocking properties, separation properties, and storage stability were at the × level, and in Comparative Example 4, the evaluation of color bleeding in the printed material was also at the × level. As described above, the pretreatment solution of the present invention uses resin particles (A1) having a specific SP value and acid value, which improves the blocking resistance of printed materials and the separation properties of layers formed from aqueous inkjet inks, while maintaining a good level of storage stability, and these results support this explanation.

[0294] Furthermore, Comparative Example 6 is a system in which the ratio (R / C) of the amount of resin particles (A) contained in 100g of pretreatment solution to the millimoles of calcium ions (C(mmol)) contained in 100g of the pretreatment solution (R(g)) is greater than 0.65, while Comparative Examples 7 to 9 are systems in which this ratio is less than 0.11. As a result of the evaluation, Comparative Example 6 showed poor performance in the evaluation of color bleeding and blocking resistance of the printed material, the separation of the layer formed from the aqueous inkjet ink on the plastic substrate, and the storage stability of the pretreatment solution. On the other hand, Comparative Examples 7 to 9 showed poor performance in the evaluation of solid coverage of the printed material and the separation of the layer formed from the aqueous inkjet ink on the paper substrate. These results also confirm that controlling the above ratio is important in order to achieve the effects of the present invention at a suitable level.

[0295] Furthermore, the mixed SP value of the water-soluble organic solvent and surfactant is 14.0 (cal / cm³). 3 ) 1 / 2 In comparative examples 11 and 12, which were larger than the above, the storage stability of the pretreatment solution was at the × level, and the evaluation of color bleeding and solid coverage of the printed material was also inferior. Conversely, the above mixed SP value was 8.0 (cal / cm²). 3 ) 1 / 2 Comparative Example 13, which was smaller than the above, showed inferior results in evaluating the color bleeding of printed materials and the separation of the water-based inkjet ink layers on the plastic substrate.

[0296] Comparative Example 5 is a reproduction of Example 75 of Japanese Patent Application Publication No. 2020-075436, which discloses a pretreatment solution having a similar configuration to the pretreatment solution of the present invention. As a result of the evaluation, it was found that the blocking properties to the PET substrate were poor, and although it was at a level that could be used in practice, the full-fill evaluation and the separation properties of the layer formed from the aqueous inkjet ink were at a △ level, not reaching a good level (◎ or ○ level). The pretreatment solution 57 used in Comparative Example 5, like Comparative Examples 7 to 9, had an excessive amount of calcium ions relative to the amount of resin particles (A1), and it is thought that even when a thickener (hydrophobic modified water-soluble urethane resin) was used in combination to optimize the viscoelasticity of the pretreatment solution, the deterioration of the above quality could not be suppressed.

[0297] Furthermore, Comparative Example 15 reproduces the pretreatment solution disclosed in Example 1 of Patent Document 8 mentioned above. (However, for the resin particles, the (meth)acrylic resin particles 19 used in other examples were used.) The pretreatment solution 146 used in Comparative Example 15 above had a mixed SP value of 14.0 (cal / cm³) of water-soluble organic solvent and surfactant. 3 ) 1 / 2 Because it was larger than the specified value, similar to Comparative Examples 11 and 12, the adhesion of the printed material and the storage stability of the pretreatment solution were at the × level, and it was also confirmed that it had poor separation properties from the plastic substrate.

Claims

1. A method for separating a layer formed from aqueous inkjet ink from a printed material, comprising the step of immersing the printed material in a basic solution, The printed material comprises, in this order, a substrate, a base-soluble pre-treatment layer formed using a pre-treatment solution, and a layer formed using the aqueous inkjet ink. The aforementioned water-based inkjet ink comprises a pigment, a resin, and water. The aforementioned pretreatment solution comprises resin particles (A), calcium ions, carboxylate ions, a water-soluble organic solvent and / or surfactant, and water. The resin particles (A) have an SP value of 9.0 to 14.0 (cal / cm³). ３ ) １／２ It also contains resin particles (A1) having an acid value of 1 to 60 mg KOH / g, The (mixed) SP value of the aforementioned water-soluble organic solvent and / or surfactant is 8.0 to 14.0 (cal / cm³). ３ ) １／２ And, A separation method in which, when R (g) is the amount of resin particles (A) contained in 100 g of the pretreatment solution, and C (moles) is the amount of calcium ions contained in 100 g of the pretreatment solution, the ratio of the value of R to the value of C (R / C) is 0.11 to 0.

65.

2. The separation method according to claim 1, wherein the carboxylate ion comprises two or more types of carboxylate ions.

3. The separation method according to claim 1 or 2, wherein the carboxylic acid ion includes a hydroxycarboxylic acid.

4. The separation method according to claim 1 or 2, wherein the ratio of the value of R to the value of C (R / C) is 0.11 to 0.

50.

5. The separation method according to claim 1 or 2, wherein the resin particles (A1) include resin particles selected from the group consisting of (meth)acrylic resin particles, urethane (urea) resin particles, urethane (urea)-(meth)acrylic resin particles, and polyester resin particles.

6. The separation method according to claim 5, wherein the resin particles (A1) include (meth)acrylic resin particles having a glass transition temperature (Tg) of -10 to 75°C.

7. The resin particles (A1) include resin particles selected from the group consisting of (meth)acrylic resin particles, urethane (urea) resin particles, urethane (urea)-(meth)acrylic resin particles, and polyester resin particles. The carboxylic acid ion includes a hydroxycarboxylic acid, The separation method according to claim 1 or 2, wherein the ratio of the value of R to the value of C (R / C) is 0.11 to 0.

50.

8. The separation method according to claim 1 or 2, wherein the absolute value of the difference between the SP value of the resin particles (A) and the (mixed) SP value of the water-soluble organic solvent and / or surfactant is 0 to 4.5.

Images