JP6977500B2 - Aqueous recording liquid set and method for manufacturing printed matter using them - Google Patents

Description

The present invention relates to a water-based recording liquid set containing a pretreatment liquid and a water-based ink, and a method for producing a printed matter using them.

Unlike conventional plate-based printing such as offset printing and gravure printing, digital printing does not require plate-making film or plate-making, so cost reduction and speeding up can be realized, and it will be widely used in the future. It is expected.

The inkjet printing method, which is a kind of digital printing, obtains characters and images by directly ejecting ink droplets from a very fine nozzle onto a printing substrate and adhering them. The inkjet printing method has advantages such as low noise of the device used, good operability, and easy colorization, and is widely used as an output device in offices and homes. Also, in industrial applications, it has begun to be used as a digital print output machine due to the improvement of inkjet technology.

Conventionally, the inks used in the inkjet printing method in industrial applications have been solvent inkjet inks and UV inkjet inks. However, in recent years, the demand for water-based inkjet inks has been increasing from the viewpoint of environmental friendliness.

The water-based ink used in the inkjet printing method (hereinafter, also simply referred to as “inkjet”) has conventionally been intended for plain paper and special paper (for example, photographic glossy paper). That is, water is the main component, and a water-soluble organic solvent such as glycerin or glycol is added in order to control the wettability and drying property with respect to the base material. When a pattern of characters or images is printed on the above-mentioned base material using a water-based inkjet ink composed of these liquid components (hereinafter, also referred to as "water-based ink jet ink", "water-based ink", or simply "ink"), The liquid component permeates the substrate, dries, and is fixed.

On the other hand, the base materials used in the inkjet printing method include not only the above-mentioned plain paper and special paper, or highly permeable paper such as high-quality paper and recycled paper, but also coated paper, art paper, and finely coated paper. There are also low-permeable materials such as, and non-permeable materials such as film base materials used for packaging materials such as foods and daily necessities. Until now, printing that can be practically used with water-based inkjet inks as described above for highly permeable base materials such as plain paper and special paper, or low permeable base materials such as coated paper and art paper. Image quality has been achieved. On the other hand, for a non-permeable base material such as a film base material used as a packaging material, the ink droplets after landing do not penetrate into the base material at all, so that the drying due to the permeation does not occur. Bleeding occurred between the droplets, and the print quality was impaired.

Further, with a film substrate, it is difficult to obtain sufficient adhesion because the ink does not penetrate at all. If the adhesion to the film substrate is insufficient, the ink film will peel off due to rubbing, etc., and the desired printed image cannot be obtained. Furthermore, the blocking phenomenon in which the ink film is removed on the back surface of the substrate when the printed matter is stacked and stored. Occurs.

Pretreatment liquid treatment for a non-permeable substrate is known to solve the problem of impairing print quality. Generally, as a pretreatment liquid for water-based inkjet ink, a material that forms a layer (ink receiving layer) that absorbs liquid components in the water-based inkjet ink to improve dryness (see Patent Documents 1 and 2) and a coloring material. By intentionally aggregating solid components contained in water-based inkjet inks such as ink and resin, a layer (ink agglomerating layer) that prevents bleeding between droplets and color unevenness and improves image quality is formed (Patent Documents 3 to 3). 4) are known.

However, in the case of the ink receiving layer, for example, when receiving a large amount of ink at one time, the image is cracked due to the swelling of the ink receiving layer, bleeding or color unevenness due to exceeding the acceptable amount, and the ink component on the receiving layer. There is a possibility that the concentration will decrease due to absorption. Further, when forming the receiving layer, it is necessary to make the coating film thickness of the pretreatment liquid thicker than in the case of the ink agglomerated layer described later. If the amount of coating is large, the drying property of the pretreatment liquid itself is lowered, and there is a concern that problems such as poor drying property may occur. As described above, when used for a non-permeable substrate such as a film substrate, the pretreatment liquid does not penetrate at all, so it is considered that the above-mentioned problems are likely to occur.

On the other hand, as an example of a pretreatment liquid using an ink agglomerated layer, Patent Document 3 describes a pretreatment liquid containing a polyvalent metal salt and (cationized) hydroxyethyl cellulose and defining a surface tension. It is said that by using the pretreatment liquid, a high-quality image having high image density, no bleeding, and excellent scratch resistance can be obtained. However, in the above document, the pretreatment liquid is actually used only for coated paper, which is a low-permeability base material, and is used for a non-permeable base material such as a film. No. Therefore, the present inventors evaluated using a polyolefin film or a nylon film, but the adhesion to these films was insufficient.

In addition, as a measure for obtaining adhesion to a non-permeable substrate, generally, a treatment method using a pretreatment liquid having an adhesion function to the impermeable substrate and a treatment method using an impermeable substrate to the ink itself There is a method of imparting a close contact function (see Patent Document 5). This is not limited to image formation using water-based inkjet inks, but also gravure printing and flexographic printing, which are used in packaging material applications where solvent inkjet inks, UV inkjet inks, and non-permeable substrates are often used. The same applies to the conventional printing method.

However, in the case of a pretreatment liquid having an adhesion function, a material such as a binder resin such as a polyurethane resin, a polyolefin resin or a polyester resin or a plasticizer used for the pretreatment liquid to impart the adhesion function to the film substrate. Is prone to problems such as blocking of printed matter and poor drying property. In addition, when a pretreatment liquid containing only the above materials is used, bleeding and color unevenness between ink droplets after landing on the pretreatment liquid layer coated on the film substrate when forming an image with an aqueous inkjet ink. May occur. That is, it is not possible to obtain a printed matter having good image quality quality only by the treatment with the pretreatment liquid.

On the other hand, even if an ink for gravure printing or the like is applied to the inkjet method in order to impart an adhesion function to the impermeable substrate to the ink itself, the ejection property from the inkjet recording head cannot be obtained, and the printed image itself is printed. I can't get it. Furthermore, since gravure printing ink is obtained by dispersing or dissolving materials such as pigments and resins in an organic solvent, special exhaust equipment is required, and there are concerns about environmental load and human body impact. Will be done.

As described above, it is possible to obtain a printed matter having excellent adhesion to a non-permeable substrate such as a film substrate, no color bleeding and color unevenness, good print image quality, and excellent blocking resistance and drying property. There has never been a water-based recording liquid set containing a water-based ink and a pretreatment liquid.

Japanese Unexamined Patent Publication No. 2000-238422 Japanese Unexamined Patent Publication No. 2000-335584 Japanese Unexamined Patent Publication No. 2005-07455 Japanese Unexamined Patent Publication No. 2016-168782 Japanese Unexamined Patent Publication No. 2009-114454

An object of the present invention is to obtain a printed matter having excellent adhesion to a non-permeable substrate such as a film substrate, no color bleeding and color unevenness, good print image quality, and excellent blocking resistance and drying property. It is an object of the present invention to provide a water-based recording liquid set containing a water-based inkjet ink and a pretreatment liquid.

That is, the present invention is a water-based recording liquid set used in an inkjet printing method for a thermoplastic resin substrate, which comprises a pretreatment liquid and one or more kinds of water-based inks.
The pretreatment liquid contains a urethane resin (A), a water-soluble organic solvent (B-1), an agglutinant (C), and water.
The glass transition temperature (Tg) of the urethane resin (A) is −100 to 35 ° C.
The urethane resin (A) contains polyurethane urea, and the urethane resin (A) contains polyurethane urea.
The water-soluble organic solvent (B-1) is 1 or more including the hydroxyl group in the molecular structure, seen containing a monovalent alcohol,
The flocculant (C) contains a metal salt having a moisture absorption mass increase rate of 50% by mass or less.
The water-based ink contains a pigment, a resin for dispersing a pigment, a water-soluble organic solvent (B-2), and water.
The pigment dispersion resin contains an aromatic ring structure and contains an aromatic ring structure.
The amount of the water-soluble organic solvent having a boiling point of 280 ° C. or higher under 1 atm contained in the water-soluble organic solvent (B-2) is 10% by mass or less with respect to the total amount of the aqueous ink.
Regarding the aqueous recording liquid set.

Further, in the present invention, the water-soluble organic solvent contained in the water-soluble organic solvent (B-2) having a boiling point of 240 ° C. or higher at 1 atm is 10% by mass or less based on the total amount of the water-based ink. Regarding liquid set.

The present invention also relates to the aqueous recording liquid set according to claim 1 or 2, wherein the blending amount of the urethane resin (A) is 4 to 40% by mass with respect to the total amount of the pretreatment liquid.

The present invention also relates to the aqueous recording liquid set in which the pretreatment liquid does not substantially contain a colorant.

The present invention also relates to the water-based recording liquid set, wherein the water-based ink includes a black ink and a white ink.

Further, the present invention is a method for producing a printed matter, wherein the aqueous recording liquid set is applied onto a thermoplastic resin base material.
The step of applying the pretreatment liquid to the thermoplastic resin base material and
A step of applying the water-based ink to the portion of the thermoplastic resin substrate to which the pretreatment liquid is applied by 1-pass inkjet printing.
The present invention relates to a method for producing a printed matter, which comprises a step of drying the thermoplastic resin base material to which the water-based ink is applied.

The present invention also relates to a printed matter in which the aqueous recording liquid set is applied onto a thermoplastic resin substrate.

According to the present invention, it is possible to obtain a printed matter having excellent adhesion to a non-permeable substrate such as a film substrate, no color mixing bleeding and color unevenness, good print image quality, and excellent blocking resistance and drying property. It has become possible to provide a water-based recording liquid set containing a water-based pigment inkjet ink and a pretreatment liquid.

Hereinafter, the aqueous recording liquid set, which is an embodiment of the present invention (hereinafter, also simply referred to as “the present embodiment”), will be described with reference to preferred embodiments.

In the pretreatment liquid and the water-based ink of the present embodiment, the pretreatment liquid contains a urethane resin (A), a water-soluble organic solvent (B-1), and water, and the glass transition of the urethane resin (A). The temperature (Tg) is -100 to 35 ° C., the water-soluble organic solvent (B-1) contains one or more hydroxyl groups in the molecular structure, and the water-based ink includes a pigment, a pigment dispersion resin, and the like. The amount of the water-soluble organic solvent containing a water-soluble organic solvent and water, the pigment dispersion resin contains an aromatic ring structure, and the water-based ink contains a water-soluble organic solvent having a boiling point of 280 ° C. or higher under 1 atm. It is 10% by mass or less with respect to the total amount of the water-based ink. As a result, it is possible to obtain a printed matter having excellent adhesion to a non-permeable substrate such as a film substrate, having no color mixing bleeding or color unevenness, good print image quality, and excellent blocking resistance and drying property. The main configurations of the aqueous recording liquid set of the present embodiment will be described below.

The pretreatment liquid of the present embodiment is applied onto a base material before printing the water-based inkjet ink, and forms a pretreatment liquid layer on the base material. As described in the prior art, a binder resin is generally used to develop the desired adhesion strength. By selecting a binder resin instead of a plasticizer when imparting adhesion, it is possible to improve the blocking resistance of the pretreatment liquid layer and the printed matter. In this embodiment, urethane resin (A) is used as this binder resin. The urethane resin (A) is obtained by a double addition reaction between a polyol and an isocyanate, and the composition and structure can be widely selected. Further, the urethane bond and the urea bond contained in the urethane resin (A) have a high cohesive force due to the intermolecular hydrogen bond, and exhibit excellent adhesion to the film substrate.

However, if the pretreatment liquid only contains the urethane resin (A), as described above, bleeding and color unevenness between ink droplets to be printed later occur, and a printed matter having excellent print quality cannot be obtained. There is a fear. In addition, blocking may occur due to deterioration of the dryness of the pretreatment liquid layer and non-uniformity during film formation. In particular, in order to obtain excellent adhesion strength, it is necessary to lower the glass transition temperature of the urethane resin (A), in which case the ink drying property and the film uniformity are deteriorated, and the blocking resistance is also apt to be deteriorated.

Therefore, as a result of diligent studies by the present inventors in order to achieve both excellent adhesion on a non-permeable substrate, print image quality, and blocking resistance, the pretreatment liquid and the water-based ink having the above-mentioned constitution were obtained. An aqueous recording solution set containing was found. The detailed mechanism is not clear, but the following can be considered. First, the pretreatment liquid of the present embodiment contains, in addition to the urethane resin (A), a water-soluble organic solvent (B-1) containing one or more hydroxyl groups in the molecular structure. Here, the water-soluble organic solvent (B-1) uniformly present in the pretreatment liquid causes a hydrogen bond with a urethane bond and / or a urea bond in the urethane resin (A), whereby the urethane resin ( A) is also considered to be uniformly present in the pretreatment liquid. As a result, non-uniformity at the time of forming the pretreatment liquid layer and deterioration of print image quality can be suppressed.

Further, the water-based ink used together with the pretreatment liquid of the present embodiment contains a pigment dispersion resin having an aromatic ring structure. As will be described later, the pigment dispersion resin is used to disperse the pigment contained in the water-based ink. When the water-based ink adheres to the pretreatment liquid layer, the aromatic ring contained in the pigment dispersion resin and the nitrogen atom in the urethane bond and / or urea bond contained in the pretreatment liquid engage in a π-cation interaction. It is thought to wake up. As a result, the pigment dispersed by the pigment dispersion resin approaches via the urethane resin, and / or the pigment dispersion resin is desorbed from the pigment, so that the pigment is aggregated / precipitated and the water-based ink is charged. Local thickening occurs, preventing bleeding and color unevenness between droplets and improving image quality. That is, in the pretreatment liquid of the present embodiment, it is considered that the urethane resin also functions as a flocculant.

Further, in the water-based ink of the present embodiment, the amount of the water-soluble organic solvent having a boiling point of 280 ° C. or higher under 1 atm is 10% by mass or less with respect to the total amount of the water-based ink. As a matter of course, the lower the boiling point of the water-soluble organic solvent contained in the water-based ink, the better the drying property of the printed matter. However, it is generally known that a water-soluble organic solvent having a low boiling point works disadvantageously for dispersion stability. On the other hand, in the water-based ink of the present embodiment, as described above, by using a pigment dispersion resin having an aromatic ring structure, excellent dispersion stability is realized and it is possible to use it in combination with a water-soluble organic solvent having a low boiling point. Become.

As described above, in order to achieve both adhesion to a non-permeable substrate such as a film substrate, print image quality, blocking resistance, and drying property, the composition of the pretreatment liquid and the water-based ink of the present embodiment is indispensable. Is.

Subsequently, each component constituting the pretreatment liquid and the ink set of the present embodiment will be described in detail below. First, the components of the pretreatment liquid (hereinafter, also simply referred to as “pretreatment liquid of the present embodiment”) constituting the aqueous recording liquid set of the present embodiment will be described.

<Urethane resin (A)>
The pretreatment liquid of this embodiment contains a urethane resin (A). As described above, the polyurethane resin (A) used in the pretreatment liquid of the present embodiment has a suitable glass transition temperature (Tg) and has very excellent adhesion. As described above, in the pretreatment liquid of the present embodiment, the urethane resin (A) functions as a binder resin for forming the pretreatment liquid layer and also as a flocculant for aggregating the pigment in the water-based ink used in combination. Conceivable.

The urethane resin (A) includes polyurethane, polyurethane urea, acrylic-modified polyurethane, and acrylic-modified polyurethane urea. Of these, polyurethane and polyurethane urea are preferable, and polyurethane urea is particularly preferable, from the viewpoint of adhesion to a non-permeable film substrate. Further, as the form, there are a water-soluble resin, a water-dispersible resin such as an emulsion or a dispersion, and a hydrosol which is an intermediate form between the two, and any of them may be used. Among them, a water-soluble resin or a hydrosol is preferable because the polar group introduced for the purpose of making it water-based has a high affinity with a PET film or a nylon film and exhibits excellent adhesion.

In the present embodiment, the urethane resin (A) may be a synthetic resin or a commercially available product. Further, these may be used alone or in combination of two or more.

(Polyol)
Examples of the polyols that can be used for the synthesis of polyurethane and polyurethane urea include polyether polyols such as PEG (polyethylene glycol), PPG (polypropylene glycol), PTMG (polytetramethylene glycol) and PTMEG (polytetramethylene ether glycol). ;
Ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, methylpentanediol, hexanediol, octanediol, nonanediol , Methylnonanediol, Diethylene Glycol, Triethylene Glycol, Dipropylene Glycol and other low molecular weight glycols, as well as adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, sebacic acid, malonic acid, glutal. Polypolypolycols obtained by dehydration condensation with dibasic acids such as acid, pimelic acid, azelaic acid, sebacic acid, dimer acid, or these anhydrides;
Polycarbonate diols;
Polybutadiene glycols;
Glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A;
Dimerdiols;
Triols such as glycerin, trimethylolethane, trimethylolpropane, 1,2,6-hexanetriol;
Various known polyols such as tetraols such as pentaerythritol; can be mentioned. These polyols may be used alone or in combination of two or more.

Among the above, it is preferable to contain polyether polyols from the viewpoint of adhesion and stability of the pretreatment liquid. Further, it is preferable to contain PEG (polyethylene glycol) and PTMG (polytetramethylene glycol).

Further, in one embodiment, the polyol constituting the urethane resin (A) preferably contains a polyol having 3 or more hydroxyl groups present in one molecule. By using such a compound, three-dimensional crosslinking is possible in the urethane resin (A), and the pretreatment liquid layer is strengthened, so that the blocking resistance of the printed matter can be further improved.

(Isocyanate)
Examples of the isocyanates that can be used for the synthesis of polyurethanes and polyurethane ureas include various known diisocyanates of aromatic, aliphatic or alicyclic group. For example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzylisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3- Phenylene diisocyanate, 1,4-phenylenedi isocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4- Diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexane diisocyanate, norbornan diisocyanate, m-tetramethylxylylene diisocyanate and dimer acid Isocyanate diisocyanate obtained by converting the carboxyl group of the above into an isocyanate group. These may be used alone or in combination of two or more.

(Introduction of carboxyl group)
As an example of a method for synthesizing polyurethane or polyurethane urea in the form of a water-soluble resin or a hydrosol, when a polyol is reacted with an isocyanate, an ionic group such as a carboxyl group or a sulfone group is introduced into the resin. Examples thereof include a method of neutralizing using a basic compound. In that case, a carboxyl group is preferable as the ionic group from the viewpoint of adhesion. As a method for introducing a carboxyl group into the resin, a polyol containing carboxyl can be used, for example, 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolvaleric acid and the like. Dimethylol alkanoic acid; diamine-type amino acids such as glutamine, asparagine, lysine, diaminopropionic acid, ornithine, diaminobenzoic acid, and diaminobenzenesulfonic acid can be used. In particular, from the viewpoint of reactivity and solubility, it is preferable to use 2,2-dimethylolpropionic acid or 2,2-dimethylolbutanoic acid. These may be used alone or in combination of two or more.

In one embodiment, the polyol or isocyanate constituting the urethane resin (A) preferably contains a total of 3 or more hydroxyl groups and carboxyl groups present in one molecule. By using such a compound, three-dimensional cross-linking is possible in the urethane resin (A) as in the case of the above-mentioned polyol, and the blocking resistance of the printed matter can be improved.

Further, the polyurethane urea can be synthesized, for example, by reacting a polyol, an isocyanate, or a polyol containing a carboxyl group to form polyurethane, and then introducing a urea bond using a chain extender or a reaction terminator. .. By introducing the urea bond, the pretreatment liquid layer becomes tougher, the blocking resistance is improved, and the adhesion to the impermeable substrate is improved. Therefore, as described above, polyurethane urea is more preferably used in the pretreatment liquid of the present embodiment.

(Chain extender)
Various known diamines can be used as chain extenders that can be used when introducing urea bonds. For example, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, ethylenediamine, propylenediamine. , Hexamethylenediamine, Isophoronediamine, Dicyclohexylmethane-4,4'-diamine, Diaminediamine obtained by converting the carboxyl group of dimer acid into an amino group, etc., and these are used alone or in combination of two or more. be able to.

(Reaction inhibitor)
Examples of the reaction terminator include dialkylamines such as di-n-dibutylamine, monoethanolamine, diethanolamine, 2-amino-2-methyl-1-propanol, tri (hydroxymethyl) aminomethane, and 2-amino-. Amino acids having hydroxyl groups such as 2-ethyl-1,3-propanediol, N-di-2-hydroxyethylethylenediamine, N-di-2-hydroxyethylpropylenediamine, N-di-2-hydroxypropylethylenediamine, and further. Examples thereof include monoamine-type amino acids such as glycine, alanine, glutamic acid, taurine, aspartic acid, aminobutyric acid, valine, aminocaproic acid, aminobenzoic acid, aminoisophthalic acid and sulfamic acid.

(Neutralizer)
As described above, when polyurethane or polyurethane urea is solubilized, it is preferable to neutralize the carboxyl group in the resin with a basic compound. Basic compounds include sodium hydroxide, potassium hydroxide, ammonia, methylamine, ethylamine, propylamine, butylamine, hexylamine, octylamine, ethanolamine, propanolamine, diethanolamine, N-methyldiethanolamine, dimethylamine, diethylamine, Examples thereof include triethylamine, N, N-dimethylethanolamine, 2-dimethylamino-2-methyl-1-propanol, 2-amino-2-methyl-1-propanol, morpholin and the like, and these are one kind or two or more kinds. Used in combination of. Ammonia is preferable from the viewpoint of residual odor of printed matter.

(Synthesis method)
Methods for synthesizing polyurethane and polyurethane urea include an acetone method using an organic solvent that is inert to isocyanate and hydrophilic, and a solvent-free synthesis method that does not use any solvent. The urethane resin (A) used in the pretreatment liquid of the present embodiment may be one using either of the above methods or any other conventionally known method, but the viscosity is adjusted by using an organic solvent. It is preferable to use the acetone method because it can be lowered and the synthesis reaction can be carried out uniformly and smoothly. Examples of the organic solvent that is inert and hydrophilic to isocyanate include ethers such as tetrahydrofuran and dioxane, esters such as ethyl acetate, ketones such as acetone, methyl ethyl ketone and cyclohexanone, dimethylformamide and N-methylpyrrolidone. Examples thereof include amides such as amides, but the organic solvent is usually removed by vacuum distillation (desolvent), and the drying speed is accelerated even when the solvent is used without desolving, so that the organic solvent has a lower boiling point than water. Is preferred. In the case of removing the solvent, for example, after adding water and a basic compound to the reaction solution, a required amount of the solvent can be distilled off under normal pressure or reduced pressure by raising the temperature.

(Commercial item)
On the other hand, as a commercially available product that can be used as the urethane resin (A) of the present embodiment, ADEKA BONTITA HUX series (manufactured by ADEKA); Juliano series (manufactured by Arakawa Chemical Industry Co., Ltd.); Parazol series (manufactured by Ohara Palladium Chemical Co., Ltd.); Superflex series, Superflex E series (above, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.); WBR series (manufactured by Taisei Fine Chemical Co., Ltd.); Hydran series (manufactured by DIC); Takelac series (manufactured by Mitsui Chemicals Co., Ltd.); Passcall series (Manufactured by Meisei Chemical Industry Co., Ltd.) and the like.

(Glass transition temperature (Tg))
From the viewpoint of obtaining adhesion to the non-absorbent substrate, the glass transition temperature (Tg) of the urethane resin (A) used in the present embodiment is −100 ° C. to 35 ° C. It is preferably −95 ° C. to 20 ° C., and more preferably −92 ° C. to 5 ° C. When the glass transition temperature is −100 ° C. or higher, deterioration of print image quality and blocking resistance can be prevented, and when the glass transition temperature is 35 ° C. or lower, the adhesion to a non-permeable substrate is excellent. The glass transition temperature is a value obtained by measurement according to JIS K-7121 using a differential operating calorimeter DSC-60 (manufactured by Shimadzu Corporation). Specifically, the temperature of the sample placed in the aluminum sample container is raised at 10 ° C./min, and the DSC curve is measured. Indium is used for temperature calibration. At the obtained endothermic peak, a tangent line is drawn with the points where the endothermic peak begins to deviate from the baseline and the point where the slope has settled down to a constant level after the peak rises, and the intersection of the tangent line and the baseline is defined as the glass transition temperature.

(Acid value)
The acid value of the urethane resin (A) is preferably 20 to 100 mgKOH / g, more preferably 30 to 90 mgKOH / g. When the acid value is 20 mgKOH / g or more, the adhesion to the impermeable substrate and the image formation with the water-based inkjet ink are excellent, and when the acid value is 100 mgKOH / g or less, the storage stability of the pretreatment liquid is excellent and stable for a long period of time. Image formation can be obtained. The acid value of the urethane resin (A) is the number of mg of potassium hydroxide (KOH) required to neutralize the acid contained in 1 g of the urethane resin (A), and is KOH in an ethanol / toluene mixed solvent. It is a value titrated with a solution. The measurement can be performed, for example, by using "potential difference automatic titration device AT-610" manufactured by Kyoto Denshi Kogyo Co., Ltd.

(Weight average molecular weight (Mw))
The weight average molecular weight (Mw) of the urethane resin (A) does not specify a specific range, but considering the adhesion to the impermeable substrate, the drying property, and the blocking resistance, 20,000 to 200, 000 is preferable. When the weight average molecular weight (Mw) is 20,000 or more, the drying property and blocking resistance are good, and when the weight average molecular weight (Mw) is 200,000 or less, the adhesion and image formation are good.

([NCO] / [OH])
In the present embodiment, when the synthesized polyurethane is used, the reaction molar ratio ([NCO] / [OH]) of the isocyanate group of isocyanate and the hydroxyl group of the polyol is 0 from the viewpoint of controlling the molecular weight of the resin and the number of urethane bonds. It is preferably 8.5 to 1.0. More preferably, it is 0.9 to 0.98. According to this range, since the amount of hydroxyl groups is equal to or greater than the amount of isocyanate groups, a urethane resin having good blocking resistance and adhesion to a non-permeable substrate can be obtained. On the other hand, when synthesizing polyurethane urea, the reaction molar ratio ([NCO] / [OH]) of the isocyanate group to the hydroxyl group is preferably 1.2 to 2.5, preferably 1.5 to 2.0. It is more preferable to have. According to this range, since the amount of isocyanate groups is larger than the amount of hydroxyl groups, a urethane prepolymer having an isocyanate group at the terminal is obtained, and the chain extension due to the reaction between the urethane prepolymer and the chain extender results in polyurethane urea. .. The reaction molar ratio ([NH] / [residual NCO]) of the amino group of the chain extender and the isocyanate group (residual NCO) of the urethane prepolymer is preferably 0.8 to 1.2, preferably 0.9. It is more preferably ~ 1.1. Within this range, polyurethane urea having good blocking resistance and adhesion to a non-permeable substrate can be obtained. The isocyanate group involved in the urea bond is the remaining isocyanate group (residual NCO) after the urethane bond is formed.

(Number of urethane bonds)
Urethane of the urethane resin (A) used in the pretreatment liquid of the present embodiment from the viewpoint of obtaining a pretreatment liquid layer having both adhesion to a non-permeable substrate and blocking resistance and further excellent film strength. The number of bonds is preferably 1.0 to 4.0 mmol / g, more preferably 1.5 to 3.5 mmol / g, and even more preferably 2.0 to 3.2 mmol / g. It is particularly preferably 2.2 to 3.0 mmol / g. When a synthetic urethane resin (A) is used, the amount and reaction conditions of the isocyanate used in the synthesis are adjusted, and when a commercial product is used as the urethane resin (A), a plurality of the commercially available products are used. The number of urethane bonds can be kept within the above range by using the above and adjusting the blending amount thereof.

The blending amount of the urethane resin (A) in the pretreatment liquid of the present embodiment is preferably 4 to 40% by mass, preferably 7 to 35% by mass, in terms of solid content with respect to the total amount of the pretreatment liquid. More preferably, it is particularly preferably 10 to 25% by mass. By keeping the blending amount of the urethane resin (A) within the above range, it is possible to obtain a printed matter having excellent adhesion on a non-permeable substrate and good print quality.

<Water-soluble organic solvent (B-1)>
The pretreatment liquid of the present embodiment contains a water-soluble organic solvent (B-1) containing one or more hydroxyl groups. By containing the above-mentioned water-soluble organic solvent (B-1), non-uniformity at the time of forming the pretreatment liquid layer can be suppressed, and the drying property of the pretreatment liquid, the wettability to the impermeable substrate, and the print image quality can be suppressed. Can be made more suitable.

Examples of the water-soluble organic solvent (B-1) preferably used for the pretreatment liquid of the present embodiment are methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 3-methoxy-1. -Monohydric alcohols such as butanol, 3-methoxy-3-methyl-1-butanol;
1,2-ethanediol, 1,2-propanediol (propylene glycol), 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3- Butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, 1,2-heptandiol, 2,2-dimethyl-1,3-propanediol , 2-Methyl-1,3-propanediol, 2-ethyl-2-methyl-1,3-propanediol, 3-methyl-1,3-butanediol, 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, ethylene glycol, diethylene glycol, triethylene Dihydric alcohols (glycols) such as glycol, dipropylene glycol, butylene glycol, dibutylene glycol;
Trihydric alcohols such as glycerin;
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 , Glycol monoalkyl ethers such as propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monomethyl ether, and tripropylene glycol monoethyl ether. ..
Among the above exemplified compounds, in the present embodiment, it is preferable to use monohydric alcohol and / or dihydric alcohol from the viewpoint of drying property and wettability to a non-permeable substrate, and monohydric alcohols are used. It is more preferable to use one or more selected from ethanol, 1-propanol, 2-propanol, 3-methoxy-1-butanol, and 3-methoxy-3-methyl-1-butanol.
Further, the above-mentioned water-soluble organic solvent (B-1) containing one or more hydroxyl groups may be used alone or in combination of two or more.

The blending amount of the water-soluble organic solvent (B-1) contained in the pretreatment liquid of the present embodiment is preferably 3 to 30% by mass, preferably 5 to 20% by mass, based on the total amount of the pretreatment liquid. More preferred. By keeping the blending amount of the water-soluble organic solvent within the above range, it is possible to obtain a pretreatment liquid having both moisturizing property, drying property and wettability to a non-absorbent substrate, and printing of the pretreatment liquid. Stable printing is possible for a long period of time regardless of the method.

In addition to the pretreatment liquid of the present embodiment, 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, and triethylene Glycoldialkyl ethers such as glycol diethyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol methyl ethyl ether, tetraethylene glycol butyl methyl ether, tetraethylene glycol diethyl ether;
2-Pyrrolidone, N-methylpyrrolidone, N-ethylpyrrolidone, ε-caprolactam, 3-methyl-2-oxazolidinone, 3-ethyl-2-oxazolidinone, 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, N, N-diethyl-β-octoxypropion Nitrogen-containing solvents such as amides;
Heterocyclic compounds such as γ-butyrolactone, γ-valerolactone, δ-valerolactone, and ε-caprolactone can be used.
The above water-soluble organic solvent may be used alone or in combination of two or more.

<Coagulant (C)>
It is more preferable that the pretreatment liquid of the present embodiment contains at least one selected from a metal salt and a cationic polymer compound as the flocculant (C). Metal salts and cationic polymer compounds have a strong function as a flocculant and are effective for agglomerating and precipitating pigments even in a small amount. Therefore, they are suitable for eliminating color bleeding and color unevenness and further improving print image quality. Is compounded in. Further, since these materials are mainly involved in the aggregation of the pigment in the ink, most of the urethane resin (A) used in combination can function not as an aggregating agent but to develop adhesion, and as a result. , It is considered that the adhesion of the printed matter is also improved. In the pretreatment liquid of the present embodiment, either a metal salt or a cationic polymer compound may be selected and used, or may be used in combination.

In one embodiment, the flocculant (C) used in the pretreatment liquid of the present embodiment preferably has low hygroscopicity. When a coagulant with low hygroscopicity is used, when the printed matter is stored in a high humidity environment or for a long period of time, it does not absorb moisture in the atmosphere and can maintain excellent adhesion and print quality for a long period of time. be.

The term "aggregator having low hygroscopicity" as used herein specifically refers to an agent having a hygroscopic mass increase rate of 50% by mass or less as measured by the following method. First, the flocculant is stored for 24 hours in an environment with a temperature of 100 ° C. and a relative humidity of 75% RH or less. If the flocculant is available only in an aqueous solution, such as a commercial product, the water should be volatilized and removed in advance, and then stored in an environment of 100 ° C. and 75% RH or less. After storage in an environment of 100 ° C. and 75% RH or less, the mass of the flocculant is measured (W1 (g)), and then stored in an environment of a temperature of 40 ° C. and a relative humidity of 80% RH for 24 hours. .. After storage in an environment of 40 ° C. and 80% RH, the mass is measured again (referred to as W2 (g)), and the rate of increase in moisture absorption mass is calculated by the following formula (1).

Equation (1): Moisture absorption mass increase rate (mass%) = 100 × {(W2-W1) / W1}

From the viewpoint of obtaining excellent adhesion and printing image quality retention effect, the moisture absorption mass increase rate of the flocculant (C) used in the pretreatment liquid of the present embodiment is preferably 50% by mass or less as described above, and is 35. It is more preferably 0% by mass or less, and particularly preferably 20% by mass or less.

(Cationic polymer compound)
When the cationic polymer compound is selected as the flocculant (C), it can be arbitrarily used as long as it reduces the dispersion function of the pigment in the ink and has suitable solubility and diffusivity. Further, one type may be used alone, or two or more types may be used in combination.

Examples of the cationic group contained in the cationic polymer compound include, but are not limited to, an amino group, an ammonium group, an amide group, and -NHCONH _{2 groups.} Further, as a material used for introducing the above-mentioned cationic group into a cationic polymer compound, for example, an amine compound such as vinylamine, allylamine, methyldiallylamine, ethyleneimine; an amide compound such as acrylamide, vinylformamide, vinylacetamide; Cyanamide compounds such as; epihalohydrin compounds such as epifluorohydrin, epichlorohydrin, methylepichlorohydrin, epibromohydrin, epiiodohydrin; cyclic vinyl compounds such as vinylpyrrolidone, vinylcaprolactam, vinylimidazole; amidine Compounds; pyridinium salt compounds; imidazolium salt compounds and the like can be mentioned.

When a cationic polymer compound is used as the flocculant (C) in the pretreatment liquid of the present embodiment, the cationic polymer compound is selected from a diallylamine structural unit, a diallylammonium structural unit, and an epihalohydrin structural unit. It is preferable to use a compound containing the above structural units, and it is more preferable to contain at least diallylammonium structural units. All of the above resins are strong electrolytes, and the dissolution stability of the resin in the pretreatment liquid is good, and the ability to reduce the dispersion of the pigment in the water-based ink is excellent.

Among them, the resin containing diallyl ammonium structural unit exhibits particularly excellent cohesiveness, and it is possible to obtain a printed matter having less color mixing bleeding and color unevenness and excellent color development on a non-permeable substrate. preferable. From the viewpoint of availability, a hydrochloride or ethyl sulfate salt of diallyldimethylammonium or diallylmethylethylammonium is preferably selected as the diallylammonium structural unit.

On the other hand, although the reason is not clear, the printed matter using the resin containing the epihalohydrin structural unit is excellent in water resistance, and is preferably selected from this point as well. Examples of the resin containing an epihalohydrin structural unit include an epihalohydrin-modified polyamine resin, an epihalohydrin-modified polyamide resin, an epihalohydrin-modified polyamide polyamine resin, and an epihalohydrin-amine copolymer. Further, epichlorohydrin or methylepichlorohydrin is preferably selected as the epichlorohydrin from the viewpoint of availability.

As the cationic polymer compound, a product synthesized by a known synthetic method may be used, or a commercially available product may be used. As specific examples of commercially available products containing diallylamine structural units, PAS-21CL, PAS-21, PAS-M-1L, PAS-M-1, PAS-M-1A, PAS-92, PAS-92A (Nittobo Medical). (Manufactured by Senka); Unisense KCA100L and KCA101L (manufactured by Senka) can be mentioned.
Further, as commercially available products of resins containing diallyl ammonium structural units, PAS-H-1L, PAS-H-5L, PAS-H-10L, PAS-24, PAS-J-81L, PAS-J-81, PAS-J -41 (manufactured by Nittobo Medical); Unisense FPA100L, FPA101L, FPA102L, FPA1000L, FPA1001L, FPA1002L, FCA1000L, FCA1001L, FCA5000L (manufactured by Senka) can be mentioned.
Further, as a commercially available product of a resin containing both a diallylamine structural unit and a diallylammonium structural unit, PAS-880 (manufactured by Nittobo Medical Co., Ltd.) can be mentioned.

Specific examples of commercially available products containing epihalohydrin structural units include FL-14 (manufactured by SNF), Alafix 100, 251S, 255, 255LOX (manufactured by Arakawa Chemical Co., Ltd.), DK-6810, 6853, 6885; WS-. 4010, 4011, 4020, 4024, 4027, 4030 (manufactured by Seiko PMC), Papiogen P-105 (manufactured by Senka), Sumire's Resin 650 (30), 675A, 6615, SLX-1 (manufactured by Taoka Chemical Industry Co., Ltd.) , Kachio Master PD-1, 7, 30, A, PDT-2, PE-10, PE-30, DT-EH, EPA-SK01, TMHMDA-E (manufactured by Yokkaichi Chemical Co., Ltd.), Jetfix 36N, 38A, 5052 There is (manufactured by Satoda Kako Co., Ltd.).

When a cationic polymer compound is used as the flocculant (C) in the pretreatment liquid of the present embodiment, the blending amount thereof is preferably 1 to 20% by mass in terms of solid content with respect to the total amount of the pretreatment liquid. It is more preferably 3 to 10% by mass. By keeping the blending amount of the cationic polymer compound within the above range, the viscosity of the pretreatment liquid can be kept within a suitable range, and a pretreatment liquid having excellent storage stability during long-term storage can be obtained. Can be done.

(Metal salt)
Even when a metal salt is selected as the flocculant (C), the dispersive function of the pigment in the water-based ink is reduced, and the dispersive property and diffusivity are suitable, as in the case of the cationic polymer compound. If so, any material can be used. Further, one type may be used alone, or two or more types may be used in combination.

In the pretreatment liquid of the present embodiment, the type of the metal salt is not particularly limited as long as it is a metal salt composed of a metal ion and an anion bonded to the metal ion. Among them, it is preferable that the metal salt contains a polyvalent metal salt because it can suppress color mixing bleeding and obtain a clear image without color unevenness by interacting with the pigment instantaneously. Further, as the polyvalent metal ion, ^{at least one selected from Ca 2+} , Mg ²⁺ , Zn ²⁺ , Al ³⁺ , Fe ²⁺ , and Fe ³⁺ can be contained not only in pigments but also in resins and the like. It is more preferable because it easily interacts with solid components. Furthermore, among them, the ^{multivalent metal ion selected from Ca 2+} , Mg ²⁺ , Zn ²⁺ , and Al ³⁺ has an advantage that it has a large aggregation effect because it has a high ionization tendency and easily generates a cation. It is preferably used. In particular, Ca ²⁺ ions are extremely preferably selected because they have a small ionic radius and easily move in the pretreatment liquid layer and in water-based ink droplets.

Specific examples of the inorganic metal salt include calcium chloride, magnesium chloride, aluminum chloride, calcium bromide, magnesium bromide, calcium nitrate, magnesium nitrate, magnesium sulfate, aluminum sulfate, calcium carbonate, magnesium carbonate and the like. It is not limited to these. Specific examples of the organic metal salt include, but are limited to, calcium salts, magnesium salts, nickel salts, zinc salts and the like of organic acids such as pantothenic acid, propionic acid, ascorbic acid, acetic acid and lactic acid. It's not something. Among these organic acid metal salts, calcium salts of lactic acid and / or acetic acid are more preferable from the viewpoint of solubility in water and interaction with the components in the aqueous ink.

The content of the metal salt in the pretreatment liquid of the present embodiment is preferably 0.5 to 8% by mass, preferably 1 to 6.5% by mass, as metal ions, based on the total amount of the pretreatment liquid. More preferably, it is particularly preferably 1.5 to 5% by mass. By keeping the content of the metal ion within the above range, it is possible to secure the wettability of the pretreatment liquid with respect to the substrate while suppressing color mixing bleeding and color unevenness. It is also preferable because it can exhibit suitable drying properties without excessive occurrence of the boiling point elevation phenomenon caused by the metal salt. The content of metal ions with respect to the total amount of the pretreatment liquid is determined by the following formula (2).

Equation (2): (Metal ion content) (% by mass) = WC × MM ÷ MC

In the general formula (2), WC represents the content of the metal salt with respect to the total amount of the pretreatment liquid, MM represents the molecular weight of the metal ions constituting the metal salt, and MC represents the molecular weight of the metal salt.

<Surfactant>
A surfactant can be used as the pretreatment liquid of the present embodiment because it is uniformly applied onto the impermeable substrate. Examples of the surfactant include siloxane-based, acrylic-based, fluorine-based, acetylenediol-based, glycol ether-based, and the like. In one preferred embodiment, a siloxane-based surfactant or an acetylenediol-based surfactant is used from the viewpoint of controlling the surface tension of the pretreatment liquid and imparting excellent wettability on the impermeable substrate. It is preferable, and particularly preferably, it is an acetylene diol-based surfactant.

The surfactant used in the pretreatment liquid of the present embodiment can be synthesized by a known method or a commercially available product can be used. When the surfactant is selected from commercially available products, for example, BY16-201, FZ-77, FZ-2104, FZ-2110, FZ-2162, F-2123, L-7001, L-7002, as siloxane-based surfactants. SF8427, SF8428, SH3749, SH8400,8032ADDITIVE, SH3773M (manufactured by Dow Corning Toray Co., Ltd.), Tegoglide410, Tegoglide432, Tegoglide435, Tegoglide440, Tegoglide450, Tegotwin4000, Tegotwin4100, Tegowet250, Tegowet260, Tegowet270, Tegowet280 (manufactured by Evonik Degussa), SAG- 002, SAG-503A (manufactured by Nissin Chemical Industries, Ltd.), BYK-331, BYK-333, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYKUV3500, BYK-UV3510 (Big Chemie) KF-351A, KF-352A, KF-353, KF-354L, KF355A, KF-615A, KF-640, KF-642, KF-643 (manufactured by Shin-Etsu Chemical Co., Ltd.), etc.
As acetylene-based surfactants, Surfinol 61, 104E, 104H, 104A, 104BC, 104DPM, 104PA, 104PG-50, 420, 440, 465, 485, SE, SE-F, Dynol 604, 607 (manufactured by Air Products & Chemicals). ), Orfin E1004, E1010, E1020, PD-001, PD-002W, PD-004, PD-005, EXP. 4001, EXP. 4200, EXP. 4123, EXP. 4300 (manufactured by Nissin Chemical Industry Co., Ltd.) and the like can be mentioned.
The above-mentioned surfactant may be used alone or in combination of two or more.

The content of the surfactant used in the pretreatment liquid of the present embodiment is 0. It is preferably 01 to 10% by mass, more preferably 0.05 to 5% by mass. Particularly preferably, it is 0.1 to 3% by mass.

Further, the surface tension of the pretreatment liquid of the present embodiment is preferably 20 to 45 mN / m, preferably 20 to 45 mN / m, from the viewpoint of having sufficient wettability on the impermeable substrate and uniformly coating. It is more preferably 40 mN / m. Particularly preferably, it is 20 to 35 mN / m. The surface tension in the present embodiment refers to the surface tension measured by the Wilhelmy method (plate method, vertical plate method) in an environment of 25 ° C.

<Water>
The content of water contained in the pretreatment liquid of the present embodiment is preferably in the range of 30 to 95% by mass, more preferably 40 to 90% by mass, and 50 to 50 to the total amount of the pretreatment liquid. It is more preferably 85% by mass. Water enhances the mutual solubility of materials such as urethane resin (A), water-soluble organic solvent (B-1), coagulant (C) and surfactant, and improves the storage stability of the pretreatment liquid. It is an indispensable material component.

<Other materials>
The pretreatment liquid of the present embodiment suppresses damage to the members used in the coating apparatus, suppresses pH fluctuations over time, and maintains the performance as the pretreatment liquid for a long period of time. A pH adjuster can be added to the treatment liquid. In the present embodiment, a material having a pH-adjustable ability can be arbitrarily selected, and in the case of basicization, an alkanolamine such as dimethylethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, etc .; Alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; alkali metal carbonates such as lithium carbonate, sodium carbonate, sodium hydrogencarbonate and potassium carbonate can be used.
For acidification, use hydrochloric acid, sulfuric acid, acetic acid, citric acid, maleic acid, maleic anhydride, succinic acid, tartaric acid, malic acid, phosphoric acid, boric acid, fumaric acid, malonic acid, ascorbic acid, glutamate, etc. be able to. The above pH adjusters may be used alone or in combination of two or more.

The blending amount of the pH adjuster is preferably 0.01 to 5% by mass, more preferably 0.1 to 4.5% by mass, based on the total amount of the pretreatment liquid. If the amount of the pH adjuster is too small, the pH will change immediately due to external stimuli such as the dissolution of carbon dioxide, while if the pH adjuster is excessively contained, the function of the metal salt in the pretreatment liquid will be impaired. Therefore, it is preferable to keep the blending amount within the above range.

Further, in the pretreatment liquid of the present embodiment, additives such as a defoaming agent, a thickener, and an antiseptic can be appropriately added in order to obtain desired physical property values. When these additives are used, the blending amount thereof is preferably 0.01% by mass or more and 10% by mass or less, and preferably 0.01% by mass or more and 5% by mass or less with respect to the total amount of the pretreatment liquid. More preferred. If it is excessively blended, the function of the flocculant in the pretreatment liquid may be impaired. Therefore, the addition amount is preferably in the above range.

The pretreatment liquid of the present embodiment preferably contains substantially no colorant or polymerizable monomer. Here, "substantially free" means that the material is not allowed to be intentionally added to the extent that the effect of the present embodiment is hindered, and for example, as an impurity or a by-product. It does not eliminate unintentional contamination. Specifically, the material is not contained in an amount of 3.0% by mass or more, preferably 1.0% by mass or more, more preferably 0.5% by mass or more, based on the total amount of the pretreatment liquid. It is not contained, and particularly preferably it is not contained in an amount of 0.1% by mass or more.

<Manufacturing method of pretreatment liquid>
The pretreatment liquid of the present embodiment comprising the above components is, for example, a urethane resin (A), a water-soluble organic solvent (B-1), and if necessary, a flocculant (C), a surfactant, and a pH. It is produced by adding a regulator and an appropriately selected additive component as described above, stirring and mixing, and then filtering as necessary. However, the method for producing the pretreatment liquid is not limited to the above.

<Aqueous recording liquid set>
The water-based recording liquid set of the present embodiment includes a pretreatment liquid and one or more kinds of water-based inks. Hereinafter, the components of the water-based ink (hereinafter, also simply referred to as “the water-based ink of the present embodiment”) constituting the water-based recording liquid set of the present embodiment will be described.

(Pigment)
The water-based ink of the present embodiment contains a pigment as a coloring material from the viewpoint of having blocking resistance, water resistance, light resistance, weather resistance, gas resistance and the like. As the pigment, either a known organic pigment or an inorganic pigment can be used. These pigments are preferably contained in the range of 2% by mass or more and 20% by mass or less, more preferably 2.5% by mass or more and 15% by mass or less, based on the total amount of the ink. It is particularly preferable that it is contained in the range of 10% by mass or less. In the case of white ink, the pigment content is preferably 3% by mass or more and 40% by mass or less, and more preferably 7% by mass or more and 30% by mass or less, based on the total mass of the white ink. .. By setting the pigment content to 2% by mass or more (3% by mass or more in the case of white ink), sufficient color development can be obtained even with 1-pass printing. In addition, by setting the pigment content to 20% by mass or less (40% by mass or less in the case of white ink), the viscosity of the ink can be kept within a range suitable for inkjet printing, and the long-term stability of the ink is also good. It can be maintained as it is, and as a result, long-term printing stability can be ensured.

Examples of the cyan organic pigment that can be used in the water-based ink of the present embodiment include C.I. I. Pigment Blue 1, 2, 3, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64, 66 and the like. Among them, C.I. I. Pigment Blue 15: 3 and / or one or more selected from 15: 4 is preferred.

Further, as the magenta organic pigment, for example, C.I. I. Pigment Red 5, 7, 12, 22, 23, 31, 48 (Ca), 48 (Mn), 49, 52, 53, 57 (Ca), 57: 1, 112, 122, 146, 147, 150, 185. , 202, 209, 238, 242, 254, 255, 266, 269, 282, C.I. I. Pigment Bio Red 19, 23, 29, 30, 37, 40, 43, 50 and the like can be used. Among them, C.I. I. Pigment Red 122, 150, 185, 202, 209, 266, 269, 282 and / or C.I. I. One or more selected from the group consisting of Pigment Violet 19 is preferable.

From the viewpoint of further enhancing the color development property, it is also preferable to use a solid solution pigment containing a quinacridone pigment as the magenta organic pigment. Specifically, C.I. I. Pigment Red 122 and C.I. I. Pigment Violet 19 and solid solution pigments, C.I. I. Pigment Red 202 and C.I. I. Pigment Violet 19 and solid solution pigments, C.I. I. Pigment Red 209 and C.I. I. Pigment Violet 19 and solid solution pigments, C.I. I. Pigment Red 282 and C.I. I. Pigment Violet 19 and solid solution pigments, C.I. I. Pigment Red 122 and C.I. I. Solid solution pigments, including Pigment Red 150, C.I. I. Pigment Red 122 and C.I. I. Pigment Red 185 and other solid solution pigments, C.I. I. Pigment Red 122 and C.I. I. Examples include solid solution pigments containing Pigment Red 269.

Further, as the yellow organic pigment, for example, C.I. I. Pigment Yellow 10, 11, 12, 13, 14, 17, 20, 24, 74, 83, 86, 93, 94, 95, 109, 110, 117, 120, 125, 128, 137, 138, 139, 147, 148, 150, 151, 154, 155, 166, 168, 180, 185, 213 and the like can be used. Among them, C.I. I. One or more selected from the group consisting of Pigment Yellow 12, 13, 14, 74, 120, 180, 185, and 213 is preferable.

Further, as the black organic pigment, for example, aniline black, lumogen black, azomethine azo black and the like can be used. It is also possible to use a plurality of chromatic pigments such as the above-mentioned cyan pigment, magenta pigment and yellow pigment, and the following orange pigment, green pigment and brown pigment to obtain a black pigment.

As the water-based ink of the present embodiment, special colors such as orange pigment, green pigment, and brown pigment can also be used. Specifically, C.I. I. Pigment Orange 16, 36, 43, 51, 55, 59, 61, 64, 71, C.I. I. Pigment Green 7, 36, 43, 58, Pigment Brown 23, 25, 26 and the like.

The inorganic pigment that can be used in the water-based ink of the present embodiment is not particularly limited, and examples thereof include carbon black and iron oxide as black pigments and titanium oxide as white pigments.

Examples of the carbon black that can be used in the water-based ink of the present embodiment include carbon black produced by the furnace method and the channel method. Among these carbon blacks, the primary particle size is 11 to 50 nm, the specific surface area by the BET method is 50 to 400 m ² / g, the volatile content is 0.5 to 10% by mass, and the pH is 2 to 10 and the like. Those having the above are suitable. As a commercially available product having such characteristics, for example, No. 25, 30, 33, 40, 44, 45, 52, 850, 900, 950, 960, 970, 980, 1000, 2200B, 2300, 2350, 2600; MA7, MA8, MA77, MA100, MA230 (Mitsubishi Chemical Corporation) , RAVEN760UP, 780UP, 860UP, 900P, 1000P, 060UP, 1080UP, 1255 (manufactured by Columbian Carbon), REGAL330R, 400R, 660R, MOGUL L (manufactured by Cabot), NipponeX160IQ, 170IQ, 35,75; 35, 40, 45, 55, 75, 80, 85, 90, 95, 300; SpecialBlack350, 550; Neurox305, 500, 505, 600, 605 (manufactured by Orion Engineered Carbons), etc., all of which are preferably used. can do.

Further, as the titanium oxide preferably used as a white pigment, both anatase type and rutile type can be used, but it is preferable to use the rutile type in order to improve the concealing property of the printed matter. Further, it may be produced by any method such as a chlorine method or a sulfuric acid method, but it is preferable to use titanium oxide produced by the chlorine method because the whiteness is high.

The titanium oxide that can be used in the water-based ink of the present embodiment is preferably a pigment surface treated with an inorganic compound and / or an organic compound. Examples of inorganic compounds include compounds of silicon (Si), aluminum, zirconium, tin, antimony, titanium, and hydrated oxides thereof. Examples of organic compounds include polyhydric alcohols, alkanolamines or derivatives thereof, higher fatty acids or metal salts thereof, organic metal compounds, etc. Among them, polyhydric alcohols or derivatives thereof have a high degree of titanium oxide surface. It can be made hydrophobic and the dispersion stability can be improved, and is preferably used.

In the water-based ink of the present embodiment, a plurality of the above pigments can be mixed and used in order to keep the hue and color development property of the printed matter within a suitable range. For example, in order to improve the tint at a low printing rate, a small amount of one or more pigments selected from cyan organic pigments, magenta organic pigments, orange organic pigments, and brown organic pigments is used for black inks using carbon black pigments. Can be added.

<Resin for pigment dispersion>
As a method for stably dispersing and holding a pigment in an aqueous ink, (1) a method of adsorbing and dispersing a water-soluble pigment-dispersed resin on the pigment surface, and (2) a water-soluble and / or water-dispersible surfactant are used as pigments. A method of adsorbing and dispersing on the surface, (3) a method of chemically and physically introducing a hydrophilic functional group on the pigment surface and dispersing it in an ink without a dispersion resin or a surfactant (self-dispersing pigment), (4). ) A method of coating the pigment with a water-insoluble resin and, if necessary, using another water-soluble pigment dispersion resin or a surfactant to disperse the pigment in the ink can be mentioned.

For the water-based ink used in the present embodiment, the method (1) or (4) above, that is, the method using the pigment dispersion resin is selected, and the pigment dispersion resin contains an aromatic ring structure. Is done. As described above, this is to improve the image quality by utilizing the π-cation interaction formed by the aromatic ring contained in the pigment dispersion resin and the nitrogen atom in the urethane bond and / or urea bond contained in the pretreatment liquid. The purpose is to secure and improve dispersion stability in water-based inks containing water-soluble organic solvents having a low boiling point. In the present specification, the term "pigment dispersion resin" is a general term for the water-soluble pigment dispersion resin used in the above methods (1) and (4) and the water-insoluble resin used in the above method (4). Is defined as.

For the water-based ink of the present embodiment, it is particularly preferable to select the method using the pigment dispersion resin of (1) among the above. By selecting and examining the monomer composition and molecular weight that make up the resin, the resin adsorption capacity for the pigment and the charge of the pigment-dispersed resin can be easily adjusted, and as a result, dispersion stability is imparted to the fine pigment. This is because it is possible to control the ability of the pretreatment liquid to reduce the dispersion function of the pigment.

The type of the pigment dispersion resin is not particularly limited, and for example, acrylic resin, styrene acrylic resin, (anhydrous) maleic acid resin, styrene (anhydrous) maleic acid resin, olefin (anhydrous) maleic acid resin, polyurethane resin, polyester resin. (Polycondensate of polyvalent carboxylic acid and polyhydric alcohol) and the like can be used. Above all, it is particularly preferable to use an acrylic resin, a styrene acrylic resin, a polyurethane resin, or a polyester resin in terms of the size of material selectivity and the ease of synthesis. Further, the above-mentioned pigment dispersion resin can be synthesized by a known method or a commercially available product can be used.

As described above, the pigment dispersion resin used in the water-based ink of the present embodiment contains an aromatic ring structure, and the amount thereof is preferably 10 to 80% by mass, preferably 15 to 80% by mass, based on the total amount of the pigment dispersion resin. It is more preferably 75% by mass, and particularly preferably 20 to 70% by mass. By keeping the amount of the aromatic ring structure within the above range, the effect of improving the image quality by utilizing the π-cation interaction and the effect of ensuring / improving the dispersion stability in the water-based ink containing a water-soluble organic solvent having a low boiling point are preferable. It will be something like that. The amount of the aromatic ring structure is the mass ratio of the aromatic ring structure in the pigment dispersion resin. For example, when a synthetic product is used as the pigment dispersion resin, the amount of the aromatic ring structure is determined by calculating the mass ratio occupied by the aromatic ring with respect to the monomer component having the aromatic ring structure, and then using the mass ratio as the pigment dispersion resin. It is an amount obtained by multiplying by the compounding mass ratio of the monomer component occupying the inside. Further, the mass ratio of the aromatic ring structure may be measured by a known method such as pyrolysis gas chromatography or NMR.

In one embodiment, the pigment dispersion resin preferably contains an alkyl group having 10 to 36 carbon atoms in addition to the aromatic ring structure. This is because by setting the number of carbon atoms of the alkyl group to 10 to 36, it is possible to reduce the viscosity of the pigment dispersion liquid, further improve the image quality, stabilize the dispersion, and stabilize the viscosity. The number of carbon atoms of the alkyl group is preferably 12 to 30, and more preferably 18 to 24 carbon atoms. The alkyl group may be linear or branched as long as it has 10 to 36 carbon atoms, but a linear group is preferable. The linear alkyl group includes a lauryl group (C12), a myristyl group (C14), a cetyl group (C16), a stearyl group (C18), an araquil group (C20), a behenyl group (C22), a lignoceryl group (C24), and a cellotoyl group. Examples thereof include a group (C26), a montanyl group (C28), a melissyl group (C30), a dotria-contanoyl group (C32), a tetratria-contanoyl group (C34), a hexatria-contanoyl group (C36) and the like.

The content of the monomer containing an alkyl chain having 10 to 36 carbon atoms in the pigment dispersion resin is such that the viscosity of the pigment dispersion is reduced and the printed matter has abrasion resistance, blocking resistance and glossiness. From the viewpoint of compatibility, it is preferably 5% by mass to 60% by mass, more preferably 10% by mass to 55% by mass, and particularly preferably 20% by mass to 50% by mass.

Further, in one embodiment, it is also preferable that the pigment dispersion resin contains an alkylene oxide group in addition to the aromatic ring structure. By introducing an alkylene oxide group, the hydrophilicity and hydrophobicity of the pigment dispersion resin can be arbitrarily adjusted to improve the dispersion stability of the water-based ink, and the alkylene oxide group is the urethane resin in the pretreatment liquid layer. (A) and the impermeable substrate cause hydrogen bonds, and the adhesion of the printed matter is particularly improved. When a water-soluble pigment dispersion resin is used as the pigment dispersion resin, it is preferable to select an ethylene oxide group as the alkylene oxide group in order to preferably exhibit the above functions. Similarly, when a water-insoluble resin is used as the pigment dispersion resin, it is preferable to select a propylene oxide group as the alkylene oxide group.

The content of the monomer having an alkylene oxide group in the pigment dispersion resin is 5% by mass to 40% by mass from the viewpoint of achieving both low viscosity of the pigment dispersion and dispersion stability and adhesion of the printed matter. It is preferably by mass, more preferably 10% by mass to 35% by mass, and particularly preferably 15% by mass to 30% by mass.

When the method (1) above is selected as a method for stably dispersing and holding the pigment in the water-based ink, that is, when the water-soluble pigment dispersion resin is used as the resin for dispersing the pigment, the solubility in the ink is increased. Therefore, it is preferable to neutralize the acid group in the pigment dispersion resin with a base. However, if an excessive amount of base is added, if the pretreatment liquid contains a cation component, the cation component will be neutralized and a sufficient effect cannot be exhibited. You need to be careful. Whether or not the amount of the base added is excessive can be confirmed, for example, by preparing a 10% by mass aqueous solution of the pigment dispersion resin and measuring the pH of the aqueous solution. Above all, in order to fully exhibit the function of the pretreatment liquid, the pH of the aqueous solution is preferably 7 to 11, and more preferably 7.5 to 10.5.

Examples of the base for neutralizing the pigment dispersion resin described above include alkanolamines such as diethanolamine, triethanolamine and N-methyldiethanolamine; aqueous ammonia; alkali metals such as lithium hydroxide, sodium hydroxide and potassium hydroxide. Hydroxide; Examples thereof include carbonates of alkali metals such as lithium carbonate, sodium carbonate, sodium hydrogencarbonate and potassium carbonate.

When the method (1) above is selected as a method for stably dispersing and holding the pigment in the ink, that is, when a water-soluble pigment dispersion resin is used as the resin for dispersing the pigment, the acid value thereof is 30 to 375 mgKOH / g. Is preferable. By keeping the acid value within the above range, the solubility of the pigment dispersion resin in water can be ensured, and the interaction between the pigment dispersion resins becomes suitable, so that the viscosity of the pigment dispersion liquid can be suppressed. It is also preferable because it can be used. When the acid value is 30 mgKOH / g or more, the solubility in water is good and the viscosity of the pigment dispersion can be suppressed, and when the acid value is 400 mgKOH / g or less, the storage stability of the pigment dispersion is excellent. The acid value of the pigment dispersion resin is more preferably 65 to 340 mgKOH / g, further preferably 100 to 300 mgKOH / g, and particularly preferably 135 to 270 mgKOH / g.

On the other hand, when the method (4) is selected, that is, when a water-insoluble resin is used as the pigment dispersion resin, the acid value thereof is preferably 0 to 100 mgKOH / g, preferably 5 to 90 mgKOH / g. Is more preferable, and even more preferably 10 to 80 mgKOH / g. When the acid value is within the above range, a printed matter having excellent blocking resistance and abrasion resistance can be obtained, which is preferable. The acid value of the pigment dispersion resin can be measured using a known device as in the case of the urethane resin (A).

The molecular weight of the pigment dispersion resin is preferably in the range of 1,000 or more and 300,000 or less, and more preferably in the range of 5,000 or more and 200,000 or less. When the molecular weight is in the above range, the pigment is stably dispersed in water, and it is easy to adjust the viscosity when applied to a water-based ink. When the weight average molecular weight is 1,000 or more, the dispersed resin is difficult to dissolve in the solvent added to the water-based ink, so that the dispersed resin is strongly adsorbed on the pigment and the dispersion stability is excellent. .. When the weight average molecular weight is 300,000 or less, the viscosity at the time of dispersion is suppressed to a low level, the ejection stability from the inkjet head is excellent, and stable printing over a long period of time becomes possible.

In the present embodiment, the blending amount of the pigment dispersion resin is preferably 1 to 60% by mass with respect to the pigment. By setting the blending amount of the pigment dispersion resin to 1 to 60% by mass with respect to the pigment, the viscosity of the pigment dispersion liquid is suppressed, and the viscosity stability and dispersion stability of the pigment dispersion liquid and the water-based ink are improved. At the same time, it is preferable because it can cause a rapid deterioration of the dispersion function when mixed with the pretreatment liquid. The ratio of the pigment to the pigment dispersion resin is more preferably 2 to 55% by mass, further preferably 4 to 50% by mass, and most preferably 5 to 45% by mass.

<Water-soluble organic solvent (B-2)>
The water-based ink of the present embodiment contains a water-soluble organic solvent (B-2), and the amount of the water-soluble organic solvent having a boiling point of 280 ° C. or higher at 1 atm is 10% by mass or less with respect to the total amount of the water-based inkjet ink. (It may be 0% by mass). By setting the amount of the water-soluble organic solvent in the above boiling point range to 10% by mass or less, the drying property and ejection stability of the water-based ink are improved, and when combined with the pretreatment liquid, image quality defects such as bleeding occur. A water-based ink with good blocking resistance can be obtained. Further, from the viewpoint of further improving print quality and blocking resistance, the amount of the water-soluble organic solvent having a boiling point of 280 ° C. or higher at 1 atm is preferably 5% by mass or less, preferably 3% by mass or less. Is more preferable, and 1% by mass or less is particularly preferable (both may be 0% by mass).

For the same reason, the amount of the water-soluble organic solvent having a boiling point of 240 ° C. or higher at 1 atm is preferably 10% by mass or less (may be 0% by mass) with respect to the total amount of the water-based ink, and is preferably 5% by mass. It is particularly preferable that it is% or less (may be 0% by mass). The amount of the water-soluble organic solvent having a boiling point of 240 ° C. or higher under 1 atm is calculated including the water-soluble organic solvent having a boiling point of 280 ° C. or higher under 1 atm.

Further, the total amount of the water-soluble organic solvent (B-2) used in the water-based ink of the present embodiment is preferably 3% by mass or more and 40% by mass or less with respect to the total amount of the water-based ink. Further, from the viewpoint of ensuring ejection stability from the water-based inkjet nozzle and sufficient wettability and drying property when combined with the pretreatment liquid, it is more preferably 5% by mass or more and 35% by mass, and 8% by mass. It is particularly preferable that it is% or more and 30% by mass or less. By setting the total amount of the water-soluble organic solvent to 3% by mass or more, the moisturizing property of the ink becomes good, and the ink has excellent ejection stability. When the total content of the water-soluble organic solvent is 40% by mass or less, an ink having good drying property can be obtained. As the water-soluble organic solvent (B-2), any known one can be used as long as it satisfies the above boiling point range and blending amount, but it can be used as a material component such as a pigment dispersant, a binder resin, and a surfactant. From the viewpoint of compatibility and affinity with the above, it is preferable to contain a glycol ether solvent and / or an alkyl polyol solvent.

The boiling point under 1 atm can be measured by using a thermal analyzer such as DSC (Differential Scanning Calorimetry).

Examples of preferably used glycol ether-based solvents having a boiling point of less than 280 ° C. at 1 atm are diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, and 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 mono Glycol mono of ethyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monobutyl ether, etc. Alkyl ethers; diethylene glycol diethyl ether, diethylene glycol isopropylmethyl ether, diethylene glycol butylmethyl ether, triethylene glycol dimethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol diethyl ether, triethylene glycol butylmethyl ether, tetraethylene glycol dimethyl ether, etc. It becomes glycol dialkyl ethers.

In particular, among the above glycol ether-based solvents, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monoethyl ether, and triethylene glycol are obtained in that both excellent moisturizing property and drying property can be achieved. Monopropyl ether, triethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, dipropylene glycol It is preferable to select monobutyl ether, diethylene glycol butyl methyl ether, triethylene glycol methyl ethyl ether, triethylene glycol diethyl ether, and triethylene glycol butyl methyl ether.

Examples of the alkyl polyol-based solvent having a boiling point of less than 280 ° C. under 1 atm include 1,2-ethanediol (ethylene glycol), 1,2-propanediol (propylene glycol), and 1,3-propanediol. 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-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-Butandiol, 3-Methyl-1,5-Pentanediol, 2-Methyl-2-propyl-1,3-Propanediol, 2-Methylpentane-2,4-diol, 2-Ethyl-1,3 -Hexanediol, diethylene glycol, dipropylene glycol, dibutylene glycol and the like can be mentioned.

Among the above-mentioned alkyl polyol-based solvents, 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, and 1,2- It is preferable to select pentanediol, 1,5-pentanediol, 1,2-hexanediol, 1,6-hexanediol, and 1,2-heptanediol.

<Binder resin>
The water-based ink of the present embodiment preferably contains a binder resin. As the binder resin, a water-soluble resin and resin fine particles are generally known. Of these, the resin fine particles have a higher molecular weight than the water-soluble resin, and the resin fine particles can lower the viscosity of the water-based ink, and a larger amount of resin can be blended in the water-based ink. Suitable for increasing resistance. Examples of the type of resin used as the resin fine particles include acrylic type, styrene acrylic type, urethane type, styrene butadiene type, vinyl chloride type, polyolefin type, polyester type and the like. Among them, acrylic-based, styrene-acrylic, urethane-based, polyolefin-based, and polyester-based resin fine particles are preferably used in consideration of the stability of the water-based inkjet ink and the resistance of the printed matter.

However, when the binder resin in the water-based ink is resin fine particles, it is necessary to consider the minimum film forming temperature (MFT) of the resin fine particles. When resin fine particles with low MFT are used, the MFT of the resin fine particles is further lowered by the water-soluble organic solvent added to the water-based ink, and the resin fine particles are fused or aggregated even at room temperature, resulting in an inkjet head nozzle. This is because clogging may occur. In order to avoid the above problem, it is preferable to adjust the monomer constituting the resin fine particles so that the MFT of the resin fine particles is 60 ° C. or higher.

The MFT can be measured by, for example, an MFT tester manufactured by Tester Sangyo Co., Ltd. Specifically, after applying a 25% by mass aqueous solution of resin fine particles on the film so that the WET film thickness is 300 μm, the film is allowed to stand on the tester with a temperature gradient applied, and white precipitates are formed after drying. The temperature at the boundary between the generated region and the region where the transparent resin film is formed is defined as MFT.

On the other hand, in consideration of the maintenance performance of the inkjet printer, the binder resin may be a water-soluble resin in the water-based ink of the present embodiment. The water-soluble resin preferably has a weight average molecular weight in the range of 8,000 or more and 50,000 or less, and more preferably 10,000 or more and 40,000 or less. By setting the weight average molecular weight to 8,000 or more, the scratch resistance, particularly the blocking resistance of the printed matter can be improved, and by setting the weight average molecular weight to 50,000 or less, the ink jet head can be used. Ink with excellent ejection stability can be obtained.

The acid value is also important when selecting a water-soluble resin as the binder resin, and the acid value is preferably 5 to 80 mgKOH / g, and more preferably 10 to 50 mgKOH / g. By setting the acid value to 5 mgKOH / g or more, resolubility of the solidified water-based ink can be obtained, clogging on the inkjet head nozzle is less likely to occur like the resin fine particles, and printing stability is improved. By setting the acid value to 80 mgKOH / g or less, the water-based ink can be suppressed to a low viscosity, and stable ejection properties can be obtained. In addition, good water resistance of the printed matter coating film can be obtained.

The content of the binder resin in the total amount of the water-based ink is in the range of 1% by mass or more and 20% by mass or less, more preferably 2% by mass or more and 15% by mass or less of the total amount of the water-based inkjet ink in terms of solid content. Yes, and it is particularly preferably in the range of 3% by mass or more and 10% by mass or less.

<Surfactant>
The water-based ink of the present embodiment preferably uses a surfactant for the purpose of adjusting the surface tension and improving the image quality. On the other hand, if the surface tension is too low, the nozzle surface of the inkjet head gets wet with the water-based ink, which impairs the ejection stability. Therefore, it is very important to select the type and amount of the surfactant. From the viewpoint of ensuring optimum wettability and realizing stable ejection from the inkjet nozzle, it is preferable to use a siloxane-based, acetylene-based, or fluorine-based surfactant, and a siloxane-based or acetylene-based surfactant is used. It is particularly preferable to do so. The amount of the surfactant added is preferably 0.01% by mass or more and 5.0% by mass or less, more preferably 0.05% by mass or more and 3.0% by mass or less, based on the total amount of the water-based ink.

In addition, the molecular weight of the surfactant is also important in terms of controlling the wettability in the process of evaporating the water-based ink and improving the quality of printed matter such as abrasion resistance and solvent resistance. The molecular weight of the surfactant is preferably 1,000 or more and 7,000 or less, and more preferably 1,500 or more and 5,000 or less in terms of weight average molecular weight. When the value is 1,000 or more, the effect of controlling wetting on the printing substrate can be enhanced, and when the value is 7,000 or less, a water-based ink having excellent storage stability can be obtained.

The surfactant used in the water-based ink of the present embodiment can be synthesized by a known method or a commercially available product can be used. When selecting a surfactant from commercially available products, for example, as a siloxane-based surfactant or an acetylene-based surfactant, those listed above as surfactants that can be used in the pretreatment liquid, and as a fluorine-based surfactant. , ZonylTBS, FSP, FSA, FSN-100, FSN, FSO-100, FSO, FS-300, Capstone FS-30, FS-31 (DuPont), PF-151N, PF-154N (Omnova), etc. Can be mentioned. The above-mentioned surfactant may be used alone or in combination of two or more. However, when ink is applied on the pretreatment liquid layer, the surface tension of the ink fluctuates greatly due to the high concentration of polyvalent metal ions mixed in the ink layer, which may cause color bleeding. Therefore, it is preferable to use two or more kinds of surfactants in combination in order to suppress fluctuations in the surface tension of the ink.

The surfactant used in the water-based ink and the surfactant used in the pretreatment liquid may be the same or different. When using different surfactants, it is better to determine the blending amount after paying attention to the surface tensions of both, as described above.

<Water>
As the water contained in the water-based ink of the present embodiment, it is preferable to use ion-exchanged water (deionized water) instead of general water containing various ions.

The water content that can be used in the water-based ink of the present embodiment is preferably in the range of 20 to 90% by mass of the total mass of the ink.

<Other ingredients>
In the water-based ink of the present embodiment, in addition to the above-mentioned components, a pH adjusting agent can be added to obtain an ink having a desired physical property value as needed, and a material having a pH adjusting ability can be arbitrarily selected. can do. For basicization, alkanolamines such as dimethylethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine; aqueous ammonia; hydroxides of alkali metals such as lithium hydroxide, sodium hydroxide, potassium hydroxide; carbonates. Alkali metal carbonates such as lithium, sodium carbonate, sodium hydrogencarbonate, and potassium carbonate can be used. For acidification, use hydrochloric acid, sulfuric acid, acetic acid, citric acid, maleic acid, maleic anhydride, succinic acid, tartaric acid, malic acid, phosphoric acid, boric acid, fumaric acid, malonic acid, ascorbic acid, glutamate, etc. be able to. The above pH adjusters may be used alone or in combination of two or more.

The blending amount of the pH adjuster is preferably 0.01 to 5% by mass, more preferably 0.1 to 3% by mass, and 0.2 to 1.5% by mass with respect to the total amount of the water-based ink. Most preferably. By keeping it within the above range, the pH does not change due to the dissolution of carbon dioxide in the air, and when the pretreatment liquid comes into contact with the water-based ink, the polyurethane resin (A) and, if necessary, are used. It is preferable because the effect of the present invention can be suitably exhibited without inhibiting the aggregation effect of the flocculant (C) used.

In addition to the above-mentioned components, the water-based ink of the present embodiment has additives such as a defoaming agent, a preservative, an infrared absorber, and an ultraviolet absorber in order to obtain an ink having desired physical property values as needed. Can be added as appropriate. As an example of the addition amount of these additives, 0.01% by mass or more and 10% by mass or less is preferable with respect to the total mass of the ink.

It is preferable that the water-based ink of the present embodiment does not substantially contain the polymerizable monomer, as in the pretreatment liquid.

<Set of water-based ink>
The water-based ink of the present embodiment may be used in a single color, but it can also be used as a set of water-based inks in which a plurality of colors are combined according to the intended use. The combination is not particularly limited, but a full-color image can be obtained by using three colors of cyan, yellow, and magenta. In addition, by adding black ink, it is possible to improve the blackness and improve the visibility of characters and the like. It is also possible to improve the color reproducibility by adding colors such as orange and green. With a film substrate, which is an example of a non-permeable substrate, a clear image can be obtained by printing white ink on a transparent film, and in particular, visibility of characters printed with black ink can be obtained. It is preferably combined because it can be raised.

<Manufacturing method of water-based ink>
The water-based ink of the present embodiment composed of the above-mentioned components is produced, for example, through the following process. However, the method for producing the water-based ink of the present embodiment is not limited to the following.

(1) Production of Pigment Dispersion Liquid When a water-soluble pigment dispersion resin is used as the pigment dispersion resin, the water-soluble pigment dispersion resin, water, and a water-soluble organic solvent, if necessary, are mixed and stirred to make them water-soluble. A pigment dispersion resin mixed solution is prepared. A pigment is added to the water-soluble pigment dispersion resin mixture, mixed and stirred (premixed), and then dispersed using a disperser. Then, if necessary, centrifugation, filtration, and adjustment of the solid content concentration are performed to obtain a pigment dispersion liquid.

Further, when producing a dispersion liquid of a pigment coated with a water-insoluble resin, a water-insoluble resin solution obtained by dissolving the water-insoluble resin in an organic solvent such as methyl ethyl ketone in advance and neutralizing the water-insoluble resin as necessary. To make. A pigment and water are added to the water-insoluble resin solution, mixed and stirred (premixing), and then dispersed using a disperser. Then, the organic solvent is distilled off by vacuum distillation, and if necessary, centrifugation, filtration, and adjustment of the solid content concentration are performed to obtain a pigment dispersion liquid.

The disperser used in the dispersion treatment of the pigment may be any generally used disperser, and examples thereof include a ball mill, a roll mill, a sand mill, a bead mill and a nanomizer. Among the above, bead mills are preferably used, and specifically, they are commercially available under trade names such as super mills, sand grinders, agitator mills, grain mills, dyno mills, pearl mills and cobol mills.

In the pigment premixing and dispersion treatment, the pigment dispersant may be dispersed only in water or in a mixed solvent of an organic solvent and water.

As a method of controlling the particle size distribution of the pigment dispersion, the size of the crushed media of the above-mentioned disperser is reduced, the material of the crushed media is changed, the filling rate of the crushed media is increased, and the stirring member ( The shape of the agitator) can be changed, the dispersion treatment time can be lengthened, the classification can be performed with a filter or a centrifuge after the dispersion treatment, and a combination of these methods can be mentioned. In order to keep the pigment in a suitable particle size range, the diameter of the pulverized media of the disperser is preferably 0.1 to 3 mm. Further, as the material of the crushing media, glass, zircon, zirconia and titania are preferably used.

(2) Preparation of water-based ink Next, the water-soluble organic solvent, water, and, if necessary, the binder resin, surfactant and other additives mentioned above are added to the pigment dispersion, and the mixture is stirred and mixed.

If necessary, the mixture may be stirred and mixed while heating in the range of 40 to 100 ° C. However, when the resin fine particles are used as the binder resin, the heating temperature is preferably lower than the MFT of the resin fine particles.

(3) Removal of coarse particles The coarse particles contained in the above mixture are removed by a method such as filtration separation or centrifugation to obtain a water-based ink. As a method for filtration and separation, a known method can be appropriately used. The opening diameter of the filter is not particularly limited as long as it can remove coarse particles and dust, but is preferably 0.3 to 5 μm, more preferably 0.5 to 3 μm. Further, when performing filtration, the filter may be a single type or a plurality of types may be used in combination.

<Characteristics of water-based ink>
The water-based ink of the present embodiment preferably has a viscosity at 25 ° C. of 3 to 20 mPa · s. In this viscosity region, stable ejection characteristics are exhibited even in a head having a normal frequency of 4 to 10 KHz to a head having a high frequency of 10 to 70 KHz. In particular, by setting the viscosity at 25 ° C. to 4 to 10 mPa · s, stable ejection can be achieved even when used for an inkjet head having a design resolution of 600 dpi or more.

The viscosity can be measured by a conventional method. Specifically, an E-type viscometer (TVE25L-type viscometer manufactured by Toki Sangyo Co., Ltd.) can be used for measurement using 1 mL of ink.

Further, the water-based ink of the present embodiment has a static surface tension of 18 to 35 mN / m at 25 ° C. from the viewpoint that a water-based ink that can be ejected stably can be obtained and a printed matter having excellent adhesion can be obtained. It is preferably 19 to 32 mN / m, more preferably 20 to 28 mN / m, and particularly preferably 20 to 28 mN / m. Further, from the viewpoint of preventing bleeding and color unevenness of the printed matter and obtaining a printed matter having excellent print quality, the surface tension of the water-based ink of the present embodiment is adjusted by adjusting the type and amount of the water-soluble organic solvent and the surfactant. Is preferably equal to or less than the surface tension of the pretreatment liquid. The static surface tension in this embodiment can be measured by the platinum plate method in an environment of 25 ° C. using, for example, a surface tension meter (CBVP-Z manufactured by Kyowa Interface Science Co., Ltd.).

Further, for the same reason as described above, the water-based ink of the present embodiment preferably has a dynamic surface tension of 25 to 40 mN / m at 25 ° C. and 10 msec, more preferably 28 to 38 mN / m, and 30. It is particularly preferable that it is ~ 36 mN / m. The dynamic surface tension in this embodiment can be measured by the maximum bubble pressure method in a 25 ° C. environment using a bubble pressure dynamic surface tension meter BP100 manufactured by Kruss.

In the water-based ink of the present embodiment, the average secondary particle size (D50) of the pigment is preferably 40 nm to 500 nm, more preferably 50 nm to 400 nm, and particularly, in order to obtain a printed matter having excellent color development. It is preferably 60 nm to 300 nm. In order to keep the average secondary particle size within the above-mentioned suitable range, the pigment dispersion treatment step may be controlled as described above.

<Manufacturing method of printed matter>
As a method for producing a printed matter in the embodiment of the water-based recording liquid set in which the pretreatment liquid of the present embodiment and the water-based ink are combined, the pretreatment liquid is applied to a non-permeable substrate and then the non-penetrating liquid is applied. A method in which the water-based ink is applied to a portion of the sex substrate to which the pretreatment liquid is applied by 1-pass inkjet printing, and further, the impermeable substrate to which the water-based ink is applied is dried. It is preferably used.

As used herein, the term "one-pass inkjet printing" refers to a method in which an inkjet head is scanned once against a stopped substrate, or a substrate is passed through the lower part of a fixed inkjet head only once for printing. Therefore, the ink is not printed again on the printed ink. However, when scanning the inkjet head, it is necessary to adjust the ejection timing in consideration of the movement of the inkjet head, and the landing position is likely to shift. Therefore, when printing the water-based ink of the present embodiment, a method of passing the substrate through the lower part of the fixed inkjet head is preferably used.

Hereinafter, a method for producing a printed matter using the aqueous recording liquid set of the present embodiment will be described.

<Method of applying pretreatment liquid>
When producing a printed matter using the aqueous recording liquid set of the present embodiment, a pretreatment liquid is preferably applied onto a non-permeable substrate before printing the water-based ink. As the application method, either a method of printing in a non-contact manner with the base material such as inkjet printing or a method of printing with the pretreatment liquid in contact with the base material may be adopted. When a printing method in which the pretreatment liquid is brought into contact with the impermeable substrate is selected as the method for applying the pretreatment liquid, from the viewpoints of device simplicity, uniform coatability, work efficiency, economy, etc. , It is preferable to adopt the roller type. The "roller type" refers to a printing type in which a pretreatment liquid is applied to a rotating roll in advance and then the pretreatment liquid is transferred to a substrate, for example, an offset gravure coater, a gravure coater, a doctor coater, a bar coater, and a blade. Examples include coaters, flexo coaters, and roll coaters.

<Drying method after applying pretreatment liquid>
In the water-based recording liquid set of the present embodiment, the pretreatment liquid is applied to the impermeable base material, the impermeable base material is dried, the pretreatment liquid on the base material is dried, and then the water-based ink is applied. It may be applied, or the water-based ink may be applied before the pretreatment liquid on the substrate is completely dried. In one embodiment, it is preferable that the pretreatment liquid is completely dried before the water-based ink is applied, that is, the liquid component of the pretreatment liquid is completely removed. This is because by applying the water-based ink after the pretreatment liquid is completely dried, a printed matter having excellent blocking resistance can be obtained without causing the water-based ink to land afterwards to cause drying defects.

The drying method used for printing the pretreatment liquid of the present embodiment is not particularly limited, and examples thereof include conventionally known methods such as a heat drying method, a hot air drying method, an infrared drying method, a microwave drying method, and a drum drying method. Can be done. The above drying method may be used alone or in combination of two or more. Above all, it is preferable to use the hot air drying method in order to reduce damage to the impermeable substrate and dry it efficiently. Further, from the viewpoint of preventing damage to the base material and bumping of liquid components in the pretreatment liquid, when the heat drying method is adopted among the above, the drying temperature should be 35 to 100 ° C., and the hot air drying method is also used. When the above is adopted, it is preferable that the hot air temperature is 50 to 150 ° C.

<Method of applying water-based ink>
As described above, the water-based ink is preferably applied by 1-pass inkjet printing to the portion of the impermeable substrate to which the pretreatment liquid is applied. The design resolution of the inkjet head used in the one-pass inkjet printing is preferably 600 dpi (DotsPerInch) or more, and more preferably 720 dpi or more, from the viewpoint of obtaining an image having excellent print quality.

<Drying method after printing with water-based ink>
After printing the water-based ink on the impermeable base material to which the pretreatment liquid is applied, it is preferable to dry the base material in order to dry the water-based ink and the undried pretreatment liquid. At that time, in order to prevent bleeding and color unevenness, it is preferable to apply the heat energy by the dryer within 20 seconds after printing, more preferably within 10 seconds, and more preferably within 5 seconds. Is particularly preferable. The drying method preferably used is the same as that for the pretreatment liquid.

<Amount of pretreatment liquid and water-based ink applied>
When printing the aqueous recording liquid set of the present embodiment, the amount of the pretreatment liquid of the present embodiment applied to the impermeable substrate is preferably ^{1 to 25 g / m 2.} By keeping the coating amount within the above range, color mixing bleeding is suppressed, and the drying property of the pretreatment liquid layer after coating becomes good, and when it adheres to the inside of the coating equipment or when the base material after printing is layered. It is possible to prevent the blocking of the printed matter and obtain a printed matter without a feeling of tackiness (stickiness).

Further, when printing the water-based recording liquid set of the present embodiment, it is preferable that the ratio of the amount of water-based ink applied to the amount of pretreatment liquid applied is 0.1 or more and 10 or less. The ratio of the applied amount is more preferably 0.5 or more and 9 or less, and particularly preferably 1 or more and 8 or less. By keeping the ratio of the applied amount within the above range, the change in the texture of the base material caused by the excessive amount of the pretreatment liquid and the insufficient effect of the pretreatment liquid due to the excessive amount of water-based ink occur. High-quality printed matter can be obtained without bleeding or color unevenness.

Further, when the water-based ink of the present embodiment is printed by the inkjet 1-pass printing method, the drop volume of the water-based ink is preferably in the range of 0.5 to 60 pL in order to realize a high-quality image. Further, when the water-based ink includes white ink and other color inks, the drop volume of the white ink is the above-mentioned from the viewpoint of obtaining an image having high sharpness and visibility and excellent print quality. It is preferably equal to or larger than the drop volume of the color ink.

<Printing speed>
When a printed matter is produced using the aqueous recording liquid set of the present embodiment, the printing speed is preferably 30 m / min or more, more preferably 50 m / min or more, and more preferably 75 m / min or more. It is more preferably 100 m / min or more, and particularly preferably 100 m / min or more.

<Non-permeable substrate>
When printing using the aqueous recording liquid set of the present embodiment, any known impermeable substrate can be used, for example, a polyvinyl chloride sheet, a PET film, a polypropylene film, a polyethylene film, or the like. A thermoplastic resin base material such as a nylon film or a metal base material such as an aluminum foil can be used. The surface of the printing medium may be smooth, uneven, or transparent, translucent, or opaque. Further, two or more of these base materials may be bonded to each other. Further, a peeling adhesive layer or the like may be provided on the opposite side of the printed surface, or an adhesive layer or the like may be provided on the printed surface after printing. Further, the shape of the base material used for printing the ink set of the present embodiment may be a roll shape or a sheet-fed shape.

Above all, in order to fully exhibit the function of the pretreatment liquid, the impermeable base material is preferably a thermoplastic resin base material, and particularly preferably a PET film, a polypropylene film, a polyethylene film, or a nylon film. ..

Further, in order to improve the print image quality by uniformly applying the pretreatment liquid of the present embodiment and to particularly improve the adhesion, corona discharge treatment or corona discharge treatment is applied to the impermeable substrate exemplified above. It is also preferable to apply a surface modification method such as plasma treatment.

<Coating treatment>
The printed matter produced by using the ink set of the present embodiment can be coated on the printed surface, if necessary. Specific examples of the coating treatment include coating / printing of a coating composition; a dry laminating method, a solvent-free laminating method, an extrusion laminating method, lamination by a hot melt laminating or the like, and any of them may be selected. , Both may be combined.

Hereinafter, a recording liquid set containing a pretreatment liquid and a water-based ink according to an embodiment of the present invention will be described in more detail with reference to Examples and Comparative Examples. In the following description, "parts" and "%" represent "parts by mass" and "% by mass", respectively, unless otherwise specified.

<Synthesis of urethane resin (A)>
(Synthesis Example 1)
In a reaction vessel equipped with a reflux condenser, a dropping funnel, a gas introduction tube, a stirrer, and a thermometer, 72.3 parts of polytetramethylene glycol having a number average molecular weight of about 2,000 and polyethylene having a number average molecular weight of about 2,000. 5 parts of glycol, 13 parts of dimethylolbutanoic acid, 8 parts of bis (2-hydroxypropyl) aniline, and 1.7 parts of 1,4-cyclohexanedimethanol were charged, replaced with dry nitrogen, and the temperature was raised to 100 ° C. Under stirring, 41.3 parts of isophorone diisocyanate was added dropwise over 20 minutes, the temperature was gradually raised to 140 ° C. (NCO / OH = 0.95), and then the reaction was carried out for another 30 minutes. Then, while cooling, 423.8 parts of ion-exchanged water containing 8.9 parts of 28% ammonia water was added to obtain an aqueous solution of urethane resin (A-1) (solid content concentration 25%). The weight average molecular weight of the urethane resin (A-1) measured by the method described later was about 40,000. The acid value of the urethane resin (A-1) was 34.8 mg / KOH.

The weight average molecular weight was determined by measuring the molecular weight distribution using a GPC (gel permeation chromatography) device (HLC-8220 GPC manufactured by Tosoh Corporation) and using polystyrene as a standard substance as a converted molecular weight. The measurement conditions are shown below.
Column: The following columns were connected in series and used.
Guard column HXL-H manufactured by Tosoh Corporation
TSKgelG5000HXL manufactured by Tosoh Corporation
TSKgelG4000HXL manufactured by Tosoh Corporation
TSKgelG3000HXL manufactured by Tosoh Corporation
TSKgelG2000HXL manufactured by Tosoh Corporation
Detector: RI (Differential Refractometer)
Measurement conditions: Column temperature 40 ° C
Eluent: Tetrahydrofuran Flow rate: 1.0 mL / min

(Synthesis Examples 2 to 7)
In the same manner as in Synthesis Example 1, using the raw material compounds shown in Table 1, aqueous solutions (solid content concentration 25%) of urethane resins (A-2) to (A-7) were obtained. Neutralization with 28% aqueous ammonia was carried out so as to be equivalent to the carboxyl group derived from dimethylolbutanoic acid, as in Synthesis Example 1.

The abbreviations of each raw material compound in Table 1 indicate the following compounds.
PTMG: Polytetramethylene glycol (number average molecular weight about 2,000, polyether polyol)
PPG: Polypropylene glycol (number average molecular weight about 2,000, polyether polyol)
PEG: Polyethylene glycol (number average molecular weight about 2,000, polyether polyol)
MPD / AA: Dehydration condensate of 3-methyl-1,5-pentanediol and adipic acid (number average molecular weight about 2,000, polyester polyol)
NPG / AA: Dehydration condensate of neopentyl glycol and adipic acid (number average molecular weight about 2,000, polyester polyol)
DMPA: 2,2-dimethylolpropionic acid DMBA: 2,2-dimethylolbutanoic acid TMP: trimethylolpropane Bis-HPA: bis (2-hydroxypropylaniline)
CHDM: 1,4-Cyclohexanedimethanol NPG: Neopentyl glycol IPDI: Isophorone diisocyanate

(Synthesis Example 8)
8 parts of polyethylene glycol (number average molecular weight about 2,000, PEG), neopentyl glycol while introducing nitrogen gas in a reactor equipped with a reflux cooling tube, a dropping funnel, a gas introduction tube, a stirrer, and a thermometer. Dehydration condensate of adipic acid (number average molecular weight about 2,000, NPG / AA) 77.6 parts, 2,2-dimethylolbutanoic acid (DMBA) 14.4 parts, and methyl ethyl ketone (MEK) 40.6 parts. The temperature was raised while mixing and stirring the parts. 62.2 parts of isophorone diisocyanate (IPDI) is added dropwise at the boiling temperature over 1 hour, and the mixture is subjected to a boiling reaction for another 4 hours to form a terminal isocyanate prepolymer. After cooling to 30 ° C, 100 parts of isopropyl alcohol is added to the terminal. A solvent solution of isocyanate prepolymer was obtained. A solvent-type polyurethane resin is prepared by gradually adding the entire amount of the obtained terminal isocyanate prepolymer solution to a mixture of 25.7 parts of isophorone diamine (IPDA) and 400 parts of isopropyl alcohol at room temperature and reacting at 40 ° C. for 2 hours. A solution was obtained. Next, 5.9 parts of 28% ammonia water and 485.8 parts of ion-exchanged water were gradually added to the solvent-type polyurethane resin solution to neutralize the solution to make it water-soluble, and further, methyl ethyl ketone and isopropyl alcohol were added under azeotrope. After distilling off, water was added to adjust the viscosity to obtain an aqueous solution (solid content concentration 25%) of a urethane resin (A-8) which is a polyurethane urea. The weight average molecular weight of the urethane resin (A-8) was about 45,000, and the acid value was 29 mg / KOH.

(Synthesis Examples 9 to 10)
In the same manner as in Synthesis Example 8, the polyurethane urea urethane resin (A-9) and the aqueous solution (solid content concentration 25%) of the polyurethane urea (A-10) were synthesized using the raw material compounds shown in Table 2. did. Neutralization with 28% aqueous ammonia was carried out so as to be equivalent to the carboxyl group derived from DMBA, as in Synthesis Example 8.

+

+

<Production example of pretreatment liquid 1>
The following materials were mixed for 1 hour with stirring, and then filtered through a membrane filter having a pore size of 1 μm to obtain a pretreatment liquid 1.
Aqueous solution of urethane resin (A-1) (solid content concentration 25%) 65 parts n-propanol 5 parts Surfinol 420 1 part Proxel GXL 0.05 parts Ion-exchanged water 28.95 parts

<Production examples of pretreatment liquids 2-23 and 31-35>
Using the materials shown in Table 3 below, pretreatment liquids 2 to 23 and 31 to 35 were obtained by the same method as in the pretreatment liquid 1.

The materials listed in Table 3 are as follows.
・ Super Flex 650
Solid content concentration: 26% Carbonate-based cationic Tg: -17 ° C
・ Super Flex 740
Solid content concentration: 40% Aromatic isocyanate-based anionic Tg: -34 ° C
・ Super Flex 460
Solid content concentration: 38% Carbonate-based anionic Tg: -10 ° C
・ Super Flex 500M
Solid content concentration: 45% Ester-based nonionic Tg: -39 ° C
・ Super Flex 150
Solid content concentration: 30% Ester / ether anionic Tg: 40 ° C
All of the above are urethane emulsions manufactured by Dai-ichi Kogyo Seiyaku.
・ WBR-2019 Taisei Fine Chemical Urethane Emulsion Solid Concentration: 32% Tg: 45 ° C
・ Movinyl 966A Styrene / acrylic resin manufactured by Nippon Synthetic Chemistry Co., Ltd. Solid content concentration: 45% Anionic Tg: -32 ° C
・ Movinyl 731 Acrylic resin manufactured by Nippon Synthetic Chemistry Co., Ltd. Solid content concentration: 46% Nonionic Tg: 0 ° C.
・ Calcium acetate Crystalline calcium acetate monohydrate manufactured by Daito Kagaku Co., Ltd. ・ Aqueous solution of cationic resin manufactured by PAS-H-1L Nittobo Medical Co., Ltd., solid content concentration: 28%
NS-625XC Aqueous solution of cationic acrylic resin manufactured by Takamatsu Oil & Fat Co., Ltd., solid content concentration: 12%
・ Malonic acid manufactured by Wako Pure Chemical Industries, Ltd. ・ n-propanol Boiling point: 97 ° C
・ Surfinol 420 acetylene diol-based surfactant manufactured by Air Products & Chemicals ・ Preservative manufactured by Proxel GXL Arch Chemicals (1,2-benzoisothiazole-3-one aqueous solution)

<Production example of resin 1 for pigment dispersion>
93.4 parts of butanol was charged in a reaction vessel equipped with a gas introduction tube, a thermometer, a condenser and a stirrer, and replaced with nitrogen gas. The inside of the reaction vessel is heated to 110 ° C., and a mixture of 35 parts of styrene, 35 parts of acrylic acid, 30 parts of lauryl methacrylate as a polymerizable monomer, and 6 parts of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator is mixed. The mixture was added dropwise over 2 hours to carry out a polymerization reaction. After completion of the dropping, the reaction was further carried out at 110 ° C. for 3 hours, then 0.6 part of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the reaction was further continued at 110 ° C. for 1 hour to obtain a solution of the pigment dispersion resin 1. Got Further, after cooling to room temperature, 37.1 parts of dimethylaminoethanol was added for neutralization, and 100 parts of water was added to make it aqueous. Then, the mixture was heated to 100 ° C. or higher, and butanol was azeotropically boiled with water to distill off butanol, and the solid content concentration was adjusted to 50%. From this, an aqueous solution having a solid content concentration of 50% for the pigment dispersion resin 1 was obtained. The weight average molecular weight of the pigment dispersion resin 1 was 28,000 when measured in the same manner as in the case of the urethane resin (A-1). The acid value of the pigment dispersion resin 1 was 272 mg / KOH.

<Production example of resins 2 to 6 for pigment dispersion>
An aqueous solution having a solid content concentration of 50% for the pigment dispersion resins 2 to 6 was obtained by the same operation as that for the pigment dispersion resin 1 except that the monomers shown in Table 4 were used as the polymerizable monomer.

The abbreviations listed in Table 4 are as follows.
St: Styrene AA: Acrylic acid BMA: Butyl methacrylate LMA: Lauryl methacrylate VMA: Behenyl methacrylate

<Production example of resin 7 for pigment dispersion>
94 parts of methyl ethyl ketone was charged in a reaction vessel equipped with a gas introduction tube, a thermometer, a condenser and a stirrer, and replaced with nitrogen gas. The inside of the reaction vessel is heated to 65 ° C., and a mixture of 60 parts of styrene, 10 parts of acrylic acid, 30 parts of lauryl methacrylate as a polymerizable monomer, and 4 parts of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) as a polymerization initiator is mixed. The mixture was added dropwise over 2 hours to carry out a polymerization reaction. After completion of the dropping, the reaction was further carried out at 65 ° C. for 3 hours, then 0.4 part of V-601 (manufactured by Wako Pure Chemical Industries, Ltd.) was added, and the reaction was further continued at 70 ° C. for 4 hours to obtain a solution of the pigment dispersion resin 7. Got Further, after cooling to room temperature, the solid content concentration was adjusted to 40%. From this, a methyl ethyl ketone solution having a solid content concentration of 40% for the pigment dispersion resin 7 was obtained. The weight average molecular weight of the pigment dispersion resin 7 was measured in the same manner as in the case of the pigment dispersion resin 1 and found to be 43,000. The acid value of the pigment dispersion resin 7 was 78 mg / KOH.

<Production example of resin 8 for pigment dispersion>
The solid content concentration of the pigment dispersion resin 8 is 40 by the same method as that of the pigment dispersion resin 7, except that the polymerizable monomer is 62 parts of styrene, 8 parts of acrylic acid, and 30 parts of methoxypolypropylene glycol # 500 methacrylate. % Methylethylketone solution was obtained. The weight average molecular weight of the pigment dispersion resin 8 was measured in the same manner as in the case of the pigment dispersion resin 1 and found to be 49,000. The acid value of the pigment dispersion resin 8 was 60 mg / KOH.

<Production example of pigment dispersion liquid 1C, 1M, 1Y, 1K>
20 parts of LIONOL BLUE 7358G (CI Pigment Blue 15: 3) manufactured by Toyo Color Co., Ltd., 10 parts of an aqueous solution of pigment dispersion resin 1 (solid content concentration 50%), and 70 parts of water are mixed to disperse. After pre-dispersion with, the main dispersion was carried out for 2 hours using a dynomill having a volume of 0.6 L filled with 1800 g of zirconia beads having a diameter of 0.5 mm to obtain a pigment dispersion liquid 1C. In addition, the above C.I. I. Pigment Blue 1M, 1Y, and 1K were obtained in the same manner as in Pigment Dispersion Liquid 1C except that Pigment Blue 15: 3 was replaced with the pigments shown below.
Magenta: Inkjet Magenta E5B02 manufactured by Clariant AG
(CI Pigment Violet 19)
Yellow: LIONOL YELLOW TT-1405G manufactured by Toyo Color Co., Ltd.
(CI Pigment Yellow 14)
Black: PinteX85 manufactured by Orion Engineered Carbons
(CI Pigment Black 7)

<Production example of pigment dispersion liquid 1W>
Mix 40 parts of CR-90-2 (CI Pigment White 6) pigment manufactured by Ishihara Sangyo Co., Ltd., 30 parts of an aqueous solution of pigment dispersion resin 1 (solid content concentration 50%), and 30 parts of water. Dispersion was carried out in the same manner as in the pigment dispersion 1C to obtain a pigment dispersion 1W.

<Production Examples of Pigment Dispersion Liquids 2 to 6 and 9 (C, M, Y, K, W)>
By using the same method as the pigment dispersion liquids 1C, 1M, 1Y, 1K and 1W, except that an aqueous solution of the pigment dispersion resins 2 to 6 (solid content concentration 50%) is used as the pigment dispersion resin. Pigment dispersions 2 and 3 (C, M, Y, K, W, respectively) were obtained.
The same as the pigment dispersions 1C, 1M, 1Y, 1K, 1W, except that BYK-190 (styrene / acrylic resin acid value 10 mgKOH / g solid content concentration 40% manufactured by Big Chemie) is used as the pigment dispersion resin. By using the method, a pigment dispersion 9 (C, M, Y, K, W, respectively) was obtained.

Table 5 shows the configurations of the pigment dispersion liquids 1 to 6 and 9.

<Production examples of pigment dispersions 7C, 7M, 7Y, 7K>
To a mixing container equipped with a stirrer, 15 parts of a methyl ethyl ketone solution (solid content concentration 40%) of the pigment dispersion resin 7 and 15 parts of methyl ethyl ketone are added, and then 50 parts of water and 0 part of dimethylaminoethanol are stirred while stirring. .9 parts were added and the mixture was further stirred for 30 minutes. After that, 20 parts of LIONOL BLUE 7358G (CI Pigment Blue 15: 3) manufactured by Toyo Color Co., Ltd. was added, and after stirring well (pre-dispersion), a volume of 0.6 L filled with 1800 g of zirconia beads having a diameter of 0.5 mm was added. The main dispersion was carried out for 2 hours using the Dynomill of. Then, the obtained dispersion was taken out, 15 parts of water was added, and then methyl ethyl ketone was distilled off under reduced pressure using an evaporator. Then, the solid content concentration was adjusted to 20% to obtain a cyan pigment dispersion liquid 7.
In addition, the above C.I. I. Pigment blues 7M, 7Y, and 7K were obtained in the same manner as the pigment dispersion 7C except that Pigment Blue 15: 3 was replaced with the pigments shown above.

<Production example of pigment dispersion liquid 7W>
Pigment dispersion except using 40 parts of CR-90-2 (CI Pigment White 6) pigment manufactured by Ishihara Sangyo Co., Ltd. and 37.5 parts of methyl ethyl ketone solution (solid content concentration 40%) of resin 7 for pigment dispersion. Dispersion was carried out in the same manner as in Liquid 7C to obtain a pigment dispersion liquid 7W.

<Production example of pigment dispersion liquid 8 (C, M, Y, K, W)>
The pigment dispersion liquid 8 (C, M, Y, K, etc.) was prepared in the same manner as in the preparation example of the pigment dispersion liquid 7 except that the methyl ethyl ketone solution of the pigment dispersion resin 7 was replaced with the methyl ethyl ketone solution of the pigment dispersion resin 8. W) was obtained.

<Production example of binder resin 1>
20 parts of toluene in a reaction vessel equipped with a gas introduction tube, a thermometer, a condenser, and a stirrer; 7.5 parts of methacrylic acid and 7.5 parts of methyl methacrylate as a polymerizable monomer; a polymerization initiator. As a result, 0.9 part of 2,2'-azobisisobutyronitrile; 3.6 parts of 2- (dodecylthiocarbonothio oilthio) -isobutyric acid; each was added. After replacing the inside of the reaction vessel with nitrogen gas, the temperature was raised to 75 ° C. and the polymerization reaction was carried out for 3 hours to obtain a copolymer (A block) composed of methacrylic acid and methyl methacrylate. The weight average molecular weight of the A block measured in the same manner as in the case of the pigment dispersion resin 1 was about 2,200.

After completion of the above polymerization reaction, the reaction system was cooled to room temperature, and then 60 parts of toluene was added to the reaction vessel; 60 parts of methyl methacrylate and 25 parts of lauryl methacrylate were added as polymerizable monomers. After replacing the inside of the reaction vessel with nitrogen gas, the temperature is raised to 75 ° C. and the polymerization reaction is carried out for 3 hours to add a copolymer (B block) composed of methyl methacrylate and lauryl methacrylate to the A block. The binder resin 1 which is the AB block polymer obtained was obtained.

Then, the reaction system was cooled to room temperature, 9.3 parts of dimethylaminoethanol was added to the reaction vessel for neutralization, and then 200 parts of water was added. Next, the obtained solution was heated, toluene was azeotropically heated with water to distill off the toluene, and then the mixture was adjusted with water so that the solid content concentration became 30%. Solid content concentration 30%) was obtained. The weight average molecular weight of the fixing resin 1 measured in the same manner as in the case of the pigment dispersion resin 1 was about 20,000. Moreover, the acid value of the binder resin 1 was 49 mg / KOH.

<Manufacturing example of inkjet ink set 1 (CMYKW)>
The materials described below were sequentially added to the mixing vessel while stirring with a disper, and stirred until sufficiently uniform. Then, filtration was performed with a membrane filter having a pore size of 1 μm. Further, by using the pigment dispersion liquids 1M, 1Y, 1K, and 1W instead of the pigment dispersion liquid 1C, a set 1 of an inkjet ink composed of four colors of C, M, Y, and K was obtained.
Pigment dispersion 1C 25 parts Binder resin (solid content concentration 50%) 25 parts 1,2-butanediol 20 parts Surfinol 465 1 part TEGO WET 280 1 part Proxel GXL 0.05 parts Ion-exchanged water 27.95 parts

<Manufacturing examples of inkjet ink sets 2 to 13 and 21 to 22>
Inkjet ink sets 2 to 13 and 21 to 22 consisting of five colors C, M, Y, K, and W are obtained by the same method as the inkjet ink set 1 except that the materials shown in Table 6 are used. rice field.

Among the materials listed in Table 6, the materials not listed in Tables 1 to 5 are as follows.
-U-COAT UWS-145 Sanyo Chemical Industries, Ltd. Polyester urethane emulsion Solid content concentration: 35%
・ Surfinol 465 acetylene diol-based surfactant manufactured by Air Products & Chemicals ・ TegoWet280 siloxane-based surfactant manufactured by Evonik Japan

[Examples 1-37, Comparative Examples 1-7]
The pretreatment liquid produced above and the inkjet ink set were combined as shown in Table 7 below, and the following evaluation was performed using the impermeable substrate shown in Table 7. The evaluation results are as shown in Table 7.

The abbreviations of the impermeable base materials used for the evaluation shown in Table 7 represent the following, respectively.
・ OPP: Polypropylene film "FOR" manufactured by Futamura Chemical Co., Ltd. (thickness 20 μm)
-PET: Polyethylene terephthalate film "E5100" manufactured by Toyobo Co., Ltd. (thickness 12 μm)
・ NY: Unitika nylon film "ON" (thickness 15 μm)

<Example of manufacturing a printing substrate to which a pretreatment liquid is applied>
In order to apply the pretreatment liquid prepared above with a wet film thickness of 4 μm, K Control Coater K202 manufactured by Matsuo Sangyo Co., Ltd., Wire Bar No. After applying the pretreatment liquid to the following impermeable substrate using 0, the film coated with the pretreatment liquid was dried in an air oven at 70 ° C. for 3 minutes to give the pretreatment liquid to the printing group. The material was made.

<Example of manufacturing printed matter using inkjet ink>
An inkjet head KJ4B-QA (manufactured by Kyocera Corporation, design resolution 600 dpi, maximum drive frequency 30 kHz) was installed on a conveyor capable of transporting a printing substrate, and was filled with inkjet ink. Next, after fixing the printing substrate to which the pretreatment liquid is applied on the conveyor, the conveyor is driven at 50 m / min, and when passing through the installation portion of the inkjet head, the inkjet ink is discharged with a drop volume of 12 pL. And printed.

<Evaluation 1: Evaluation of adhesion>
Based on the above-mentioned production example of the printing substrate to which the pretreatment liquid was applied, five printing substrates to which the pretreatment liquid was applied were produced. Further, based on the above-mentioned production example of printed matter, ink was filled in the order of C, M, Y, K, and W from the inkjet head on the upstream side, and then solid printing with a printing rate of 100% was performed for each color. .. Within 10 seconds after printing, the printed matter was placed in an air oven at 70 ° C. and dried for 3 minutes to prepare a solid printed matter. Nichiban's cellophane tape (width 18 mm) was firmly attached to the surface of the prepared printed matter with the pad of a finger, and after confirming the close contact state, the tip of the cellophane tape was held and pulled off momentarily while maintaining an angle of 45 degrees. The surface of the printed matter and the surface of the cellophane tape after peeling were visually confirmed, and the adhesion was evaluated. The evaluation results are as follows, and ◎, ○, and △ are the areas that can be used in practice. In Table 7, among the five colors, the one with the worst evaluation result is described.
⊚: The peeling area of the cellophane tape with respect to the contact surface was 0 to 5% 〇: The peeling area of the cellophane tape with respect to the contact surface was 5 to 10% Δ: The peeling area of the cellophane tape with respect to the contact surface was 10 to 15 %: The peeled area of the cellophane tape with respect to the contact surface was larger than 15%.

<Evaluation 2: Evaluation of mixed color bleeding>
As a printed image, a 4C (CMYK) image in which the total print rate (total of the print rates of each color) is continuously changed from 40 to 320% (however, the print rate of each color is the same in each total print rate). A 4C printed matter was produced on a film substrate coated with the pretreatment liquid by printing under the same conditions as in Evaluation 1 above, except that The dot shape of the 4C printed matter was observed at a magnification of 200 using an optical microscope, and the color mixing bleeding was evaluated. The evaluation results are as follows, and ◎, ○, and △ are the areas that can be used in practice.
⊚: Dots in the 4C printing section were independent at any printing rate, and no color mixing bleeding was observed. ○: Dots in the 4C printing section with a total printing rate of 40 to 280% were independent, and color mixing bleeding was observed. Not seen Δ: Dots in the 4C printing section with a total printing rate of 40 to 240% were independent, and no color mixing bleeding was seen. ×: Color mixing bleeding was clearly seen in the 4C printing section with a total printing rate of 40 to 200%. has seen

<Evaluation 3: Evaluation of color unevenness>
Using the same printed matter as in Evaluation 2 above, the degree of color unevenness was visually observed to evaluate the color unevenness. The evaluation results are as follows, and ◎, ○, and △ are the areas that can be used in practice.
⊚: No color unevenness was observed in the 4C printing area at any of the total printing rates. ○: No color unevenness was observed in the 4C printing area with a printing rate of 280%. Δ: Color of the 4C printing area with a printing rate of 240%. No unevenness was seen ×: Color unevenness was clearly seen in the 4C printing section with a printing rate of 240%.

<Evaluation 4: Evaluation of dryness>
The same conditions as in Evaluation 1 above except that a 4C (CMYK) solid image with a total print rate of 320% (however, the print rate of each color at each total print rate is the same) was used as the print image. A 4C solid image having a total printing rate of 320% was printed on a film substrate coated with the pretreatment liquid. Immediately after printing, the printed matter was placed in an air oven at 70 ° C. and dried for a predetermined time, and then the surface of the printed matter was rubbed with a finger and the state of the surface of the printed matter was visually observed to evaluate the drying property. The evaluation results are as follows, and ◎, ○, and △ are the areas that can be used in practice.
⊚: The printed matter dried in 1 minute, and the ink on the printed surface could not be removed by rubbing with a finger. 〇: The printed matter dried in 2 minutes, and the ink on the printed surface could not be removed by rubbing with a finger. Δ: The printed matter dried in 3 minutes, and the ink on the printed surface could not be removed by rubbing with a finger. ×: The printed matter did not dry in the drying time of 3 minutes, and the ink on the printed surface was removed by rubbing with a finger.

<Evaluation 5: Evaluation of blocking resistance>
A 4C (CMYK) solid image with a total print rate of 320% is printed under the same conditions as in the above evaluation 4, and the printed matter is placed in a 70 ° C. air oven within 10 seconds after printing and dried for 3 minutes to achieve a total print rate. A 320% 4C solid printed matter was produced. This printed matter was cut into 4 cm × 4 cm squares, superposed on the back surface of the same impermeable substrate used for printing, and a blocking test was carried out using a permanent strain tester. The environmental conditions for the blocking test were a load of 10 k / cm ² , a temperature of 40 ° C., a humidity of 80%, and a test period of 24 hours. After 24 hours, the stacked impermeable base material was momentarily peeled off while maintaining an angle of 90 degrees, and the printed surface after the peeling was visually confirmed to evaluate the blocking resistance. The evaluation results are as follows, and ◎, ○, and △ are the areas that can be used in practice.
⊚: The peeling area of the printed coating film was 0 to 5% 〇: The peeling area of the printed coating film was 5 to 10% Δ: The peeling area of the printed coating film was 10 to 15% ×: The peeled area of the printed coating was larger than 15%

<Evaluation 6: Evaluation of clarity and visibility>
Based on the above-mentioned production example of printed matter, ink was filled in the order of W and K from the inkjet head on the upstream side. As the print image, a solid white image with a print rate of 100% is used for W ink, and a character image consisting of 4 points, 6 points, and 8 points of MS Mincho, which is a mixture of hiragana and kanji, is used for K ink. , Printed. Within 10 seconds after printing, the printed matter was placed in an air oven at 70 ° C. and dried for 3 minutes to prepare a solid white character printed matter in which the character image was formed on the solid white image. Then, the obtained solid white and printed matter of characters were visually observed to evaluate the sharpness and visibility. The evaluation criteria are as follows, and ◎, ○, ▲, and △ are the practically usable areas.
⊚: The characters of 4 points, 6 points, and 8 points were all clear and clearly legible.
◯: The 4-point characters were slightly inferior in clarity but could be sufficiently read, and the 6-point and 8-point characters were clear and clearly legible.
▲: The 4-point characters were inferior in clarity and could not be read. The 6-point characters were slightly inferior in clarity, but they were sufficiently legible, and the 8-point characters were clear and clearly legible.
Δ: The 4-point and 6-point characters were inferior in sharpness and could not be read. On the other hand, the 8-point characters were slightly inferior in clarity, but were sufficiently legible.
X: Characters of 4 points, 6 points, and 8 points were inferior in sharpness and could not be read.

Comparative Examples 1 and 2 are examples of the pretreatment liquid in which the glass transition temperature (Tg) of the urethane resin (A) is larger than 35 ° C., resulting in inferior adhesion to the OPP substrate and blocking resistance. Comparative Examples 3 and 4 are examples of the pretreatment liquid containing no urethane resin (A), and the results were that the adhesion to the OPP substrate, the drying property, the blocking resistance, and the sharpness / visibility were inferior. Comparative Example 5 is an example of a pretreatment liquid containing no water-soluble organic solvent (B-1), resulting in inferior bleeding, color unevenness, and sharpness / visibility. Comparative Example 6 is an example of a water-based inkjet ink that does not contain a water-soluble organic solvent (B-2), resulting in inferior bleeding, color unevenness, and sharpness / visibility. Comparative Example 7 is an example in which the water-soluble organic solvent (B-2) having a boiling point of 280 ° C. or higher under 1 atm exceeds 10% by mass with respect to the total amount of the water-based inkjet ink, and is used as an OPP substrate. As a result, the adhesion, drying property, and blocking resistance of the ink were inferior.

In contrast to the above comparative examples, the pretreatment liquids 1 to 23 used in Examples 1 to 37 were a urethane resin (A) having a glass transition temperature (Tg) of -100 to 35 ° C. and a water-soluble organic solvent (B-). 1) and water, and the water-based inkjet ink contains a pigment, a water-soluble organic solvent (B-2), and water, and the water-soluble organic solvent (B-2) contained in the water-based inkjet ink. ) Is 10% by mass or less of a water-soluble organic solvent having a boiling point of 280 ° C. or higher under 1 atm with respect to the total amount of water-based ink, and has adhesion, drying property, bleeding, color unevenness, blocking resistance, and sharpness / visibility. Good results were obtained for all of the evaluations.

Claims (7)

A water-based recording liquid set used in an inkjet printing method for a thermoplastic resin substrate, which comprises a pretreatment liquid and one or more types of water-based inks.
The pretreatment liquid contains a urethane resin (A), a water-soluble organic solvent (B-1), an agglutinant (C), and water.
The glass transition temperature (Tg) of the urethane resin (A) is −100 to 35 ° C.
The urethane resin (A) contains polyurethane urea, and the urethane resin (A) contains polyurethane urea.
The water-soluble organic solvent (B-1) is 1 or more including the hydroxyl group in the molecular structure, seen containing a monovalent alcohol,
The flocculant (C) contains a metal salt having a moisture absorption mass increase rate of 50% by mass or less.
The water-based ink contains a pigment, a resin for dispersing a pigment, a water-soluble organic solvent (B-2), and water.
The pigment dispersion resin contains an aromatic ring structure and contains an aromatic ring structure.
The amount of the water-soluble organic solvent having a boiling point of 280 ° C. or higher under 1 atm contained in the water-soluble organic solvent (B-2) is 10% by mass or less with respect to the total amount of the aqueous ink.
Aqueous recording liquid set. The aqueous recording solution according to claim 1, wherein the water-soluble organic solvent having a boiling point of 240 ° C. or higher at 1 atm contained in the water-soluble organic solvent (B-2) is 10% by mass or less based on the total amount of the aqueous ink. set. The aqueous recording liquid set according to claim 1 or 2, wherein the blending amount of the urethane resin (A) is 4 to 40% by mass with respect to the total amount of the pretreatment liquid. The aqueous recording liquid set according to any one of claims 1 to 3, wherein the pretreatment liquid does not substantially contain a colorant. The water-based recording liquid set according to any one of claims 1 to 4 , wherein the water-based ink comprises a black ink and a white ink. A method for producing a printed matter, wherein the aqueous recording liquid set according to any one of claims 1 to 5 is applied onto a thermoplastic resin substrate.
The step of applying the pretreatment liquid to the thermoplastic resin base material and
A step of applying the water-based ink to the portion of the thermoplastic resin substrate to which the pretreatment liquid is applied by 1-pass inkjet printing.
A method for producing a printed matter, which comprises a step of drying the thermoplastic resin base material to which the water-based ink is applied. A printed matter obtained by applying the aqueous recording liquid set according to any one of claims 1 to 5 onto a thermoplastic resin substrate.