JPWO2019004060A1 - Pretreatment liquid for printing, substrate for printing, method for producing substrate for printing, ink set, and image recording method - Google Patents

Abstract

A pretreatment liquid for printing comprising a polymer containing the structural unit I represented by the following formula I and water.

Description

  The present disclosure relates to a pretreatment liquid for printing, a printing substrate, a method for manufacturing a printing substrate, an ink set, and an image recording method.

The recording method using the ink jet method is widely used because a high quality image can be recorded on a wide variety of substrates by ejecting ink in a droplet form from a large number of nozzles provided in the ink jet head. It's being used.
Various forms have been proposed for an image recording method using an ink jet method.
For example, a method is known in which an ink set is used in which an ink containing water and a colorant is used in combination with a printing pretreatment liquid containing an aggregating agent for aggregating components in the ink. In this method, for example, an image having excellent resolution can be formed by bringing the ink and the pretreatment liquid for printing into contact with each other.

  Patent Literature 1 includes a colorant, polymer particles, water, and an aqueous organic solvent, has a static surface tension of less than 30 mN / m, and has a dynamic surface tension of 1 msec when measured by a maximum bubble pressure method. A group consisting of polyurethane, polyester, polyvinyl chloride, and polyolefin on at least one surface of which ink has a dynamic surface tension variation range from 0.2 mN / m to 3.0 mN / m from 1 to 1 sec. A printing apparatus is described which includes a discharge head for discharging onto the underlayer of a non-permeable recording medium having a underlayer containing one selected polymer compound.

  Patent Document 1: JP-A-2006-30337

Patent Document 1 describes that an image excellent in abrasion resistance is recorded by applying a specific ink on a non-permeable base having a base layer containing a specific polymer compound. I have.
However, as a result of intensive studies, the present inventors have found that when printing is performed by the method described in Patent Document 1, the underlayer and the base material of the surface treatment composition, or the underlayer and the ink image Has low adhesion, and the printed image may be peeled off.
In particular, when the printed substrate is taken up as a roll in the printing step, the non-image portion on the printing surface and the back surface of the substrate are in contact with each other in the roll, so the image peeled off from the printing surface is the same as that of the substrate. In some cases, it adhered to the back surface.
For example, when a transparent base material (for example, a resin base material) is used as the base material and such a peeled image adheres to the back surface of the base material, the peeled image attached to the back surface is visually recognized from the printed surface, and the printed material is printed. The appearance was sometimes impaired.

A problem to be solved by an embodiment according to the present disclosure is to provide a pretreatment liquid for printing in which peeling of an image from an obtained printed matter is suppressed.
Furthermore, a problem to be solved by another embodiment according to the present disclosure is to provide a printing substrate, a method of manufacturing a printing substrate, an ink set, or image recording in which peeling of an image from an obtained printed matter is suppressed. Is to provide a way.

Specific means for solving the problems include the following aspects.
<1> a polymer containing a structural unit I represented by the following formula I,
A pretreatment liquid for printing, comprising: water.

In Formula I, Z ⁺ represents a counter cation that may be bonded to SO ₃ ⁻ or may be dissociated.
<2> The pretreatment liquid for printing according to <1>, wherein the polymer further includes a structural unit II represented by the following formula II.

  <3> The pretreatment liquid for printing according to <1> or <2>, wherein the polymer further includes a structural unit III represented by the following formula III.

  <4> The polymer contains at least one of a structural unit II represented by the following formula II and a structural unit III represented by the following formula III, and a content of the structural unit I in the polymer, The molar ratio of the sum of the content of the unit II and the content of the structural unit III is such that the content of the structural unit I: the sum of the content of the structural unit II and the content of the structural unit III = 1: 1 to 1:40. The pretreatment liquid for printing according to 1>.

<5> The method according to any one of <1> to <4>, further including at least one coagulant selected from the group consisting of a salt of a polyvalent metal compound, an organic acid, and a cationic compound. Pretreatment liquid for printing.
<6> The mass ratio of the solid content of the polymer to the solid content of the coagulant in the pretreatment liquid for printing is such that the content of the polymer: the content of the coagulant = 10: 1 to 1: 2. The pretreatment liquid for printing according to <5>.
<7> The pretreatment liquid for printing according to <5> or <6>, wherein the coagulant contains an organic acid.
<8> The pretreatment liquid for printing according to any one of <5> to <7>, wherein the organic acid includes a dicarboxylic acid.
<9> A printing substrate comprising a non-permeable medium and a solidified product of the pretreatment liquid for printing according to any one of <1> to <8>.
<10> A method for producing a printing substrate, comprising: a pretreatment step of applying the printing pretreatment liquid according to any one of <1> to <8> to a non-permeable medium.
<11> an ink composition containing a colorant and water, and
An ink set comprising the pretreatment liquid for printing according to any one of <1> to <8>.
<12> a pretreatment step of applying the printing pretreatment liquid according to any one of <1> to <8> to a non-permeable medium;
An image recording step of recording an image by discharging an ink composition containing a colorant and water on the surface to which the printing pretreatment liquid has been applied by an inkjet method.
<13> An image recording step of recording an image by discharging an ink composition containing a colorant and water by an inkjet method on the surface to which the printing pretreatment liquid according to <10> is applied. Image recording method.

According to the embodiment of the present disclosure, it is possible to provide a pretreatment liquid for printing in which peeling of an image from an obtained printed matter is suppressed.
Further, according to another embodiment of the present disclosure, there is provided a printing substrate, a method of manufacturing a printing substrate, an ink set, or an image recording method, in which peeling of an image from an obtained printed matter is suppressed. be able to.

FIG. 1 is a schematic configuration diagram illustrating a configuration example of an inkjet recording apparatus used for performing image formation. It is a figure in an Example which shows the character in the character image used for evaluation of the image resolution conceptually. FIG. 9 is a diagram for explaining details of evaluation criteria for image resolution in an example.

In the present disclosure, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit and an upper limit.
In the present disclosure, the amount of each component in the composition, when there are a plurality of substances corresponding to each component in the composition, unless otherwise specified, means the total amount of the plurality of substances present in the composition I do.
In the present disclosure, the term “step” is included in the term, not only as an independent step but also as long as the intended purpose of the step is achieved even when it cannot be clearly distinguished from other steps.
In the present disclosure, “(meth) acryl” means at least one of acryl and methacryl, and “(meth) acrylate” means at least one of acrylate and methacrylate.
In the present disclosure, unless otherwise specified, the weight average molecular weight (Mw) or the number average molecular weight (Mn) of the polymer component is determined by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent. It is a value of conversion.
In the present disclosure, a combination of preferred embodiments is a more preferred embodiment.

(Pretreatment liquid for printing)
The pretreatment liquid for printing according to the present disclosure includes a polymer containing the structural unit I represented by the above formula I (hereinafter, also referred to as “specific polymer”),
And water.

By using the pretreatment liquid for printing according to the present disclosure, exfoliation of an image from an obtained printed matter is suppressed.
The reason for obtaining the above effects is not clear, but is presumed as follows.
Although the detailed mechanism is unknown, the specific polymer in the pretreatment liquid for printing contains the structural unit I represented by the formula I, whereby the base material (particularly, a non-permeable resin base material) It is considered that the adhesiveness between the specific polymer and the ink is excellent, and the adhesiveness between the specific polymer and the ink is also excellent.
Hereinafter, each component contained in the pretreatment liquid for printing according to the present disclosure will be described in detail.

<Polymer>
[Structural unit I represented by formula I]
The pretreatment liquid for printing according to the present disclosure includes a polymer containing a structural unit I represented by the following formula I (also simply referred to as “structural unit I”).
The structural unit I represented by the formula I can be introduced into a specific polymer by using, for example, dimethyl 2-sulfosuccinate as a monomer for obtaining the specific polymer.

In Formula I, Z ⁺ represents a counter cation that may be bonded to SO ₃ ⁻ or may be dissociated.
In the formula I, Z ⁺ may be bonded to SO ₃ ⁻ or may be dissociated, but it is preferable that Z ⁺ is at least partially dissociated.
In Formula I, Z ⁺ is preferably Na ⁺ , K ⁺ or H ⁺ .

  The specific polymer used in the present disclosure preferably contains the structural unit I in an amount of 0.1% by mass to 90% by mass, and preferably 0.5% by mass to 70% by mass, based on the total mass of the specific polymer. More preferably, the content is 1% to 50% by mass.

[Structural unit II represented by formula II]
The specific polymer used in the present disclosure preferably further includes a structural unit II represented by the formula II (also simply referred to as “structural unit II”).
When the specific polymer used in the present disclosure further includes the structural unit II, peeling of the obtained image is further suppressed.
In addition, when the specific polymer used in the present disclosure further contains the structural unit II, the resulting image has improved abrasion resistance.
The structural unit II can be introduced into a specific polymer by using, for example, dimethyl phthalate, dimethyl isophthalate, or dimethyl terephthalate as a monomer for obtaining the specific polymer.

  The structure represented by two —C (＝ O) — in Formula II may be in any of the ortho, meta, and para positions in the benzene ring in Formula II.

The specific polymer used in the present disclosure preferably contains 0.5% to 90% by mass, and preferably 1% to 80% by mass of the structural unit II represented by the formula II based on the total mass of the specific polymer. %, More preferably 5 to 75% by mass.
In the specific polymer used in the present disclosure, the molar ratio of the content of the structural unit I to the content of the structural unit II is structural unit I: structural unit II = 1: 0.1 to 1:60. The ratio is preferably 1: 0.5 to 1:50, more preferably 1: 1 to 1:40.

[Structural unit III represented by formula III]
The specific polymer used in the present disclosure preferably further includes a structural unit III represented by the formula III (also simply referred to as “structural unit III”).
When the specific polymer used in the present disclosure further includes the structural unit III, peeling of the obtained image is further suppressed.
In addition, when the specific polymer used in the present disclosure further contains the structural unit III, the resulting image has improved abrasion resistance.
The structural unit III can be introduced into the specific polymer by using 1,4-cyclohexanedimethanol as a monomer for obtaining the specific polymer, for example.
The bonding position of the _two —CH ₂ —O— in the structural unit III is not particularly limited, but may be bonded to the 1- and 4-position carbon atoms in the cyclohexane ring structure in the structural unit III, or may be the 1-position. And preferably bonded to the carbon atoms at the 1- and 4-positions, respectively.

The specific polymer used in the present disclosure preferably contains 0.5% to 90% by mass, and preferably 1% to 80% by mass of the structural unit III represented by the formula III based on the total mass of the specific polymer. %, More preferably 5 to 75% by mass.
In the specific polymer used in the present disclosure, the molar ratio of the content of the structural unit I to the content of the structural unit III is structural unit I: structural unit III = 1: 0.1 to 1:60. The ratio is preferably 1: 0.5 to 1:50, more preferably 1: 1 to 1:40.

(Content ratio)
The specific polymer used in the present disclosure includes at least one of the structural unit II and the structural unit III, the content of the structural unit I in the specific polymer, and the upper structural unit II and the structural unit in the specific polymer. Preferably, the molar ratio of the sum of the contents of III to the sum of the contents of the structural units I: the sum of the contents of the structural units II and III = 1: 0.1 to 1:60, and 1: The ratio is more preferably from 0.5 to 1:50, and even more preferably from 1: 1 to 1:40.
In the above embodiment, when either one of the structural unit II and the structural unit III is not included, the calculation is performed on the assumption that the content of the structural unit not included is 0.
In addition, from the viewpoint of suppressing peeling of the obtained image and the viewpoint of abrasion resistance, in the above embodiment, the specific polymer used in the present disclosure preferably contains both the structural unit II and the structural unit III.

[Other structural units]
The specific polymer according to the present disclosure may further include at least one of the structural units represented by the following formulas A-1 to A-4.
From the viewpoint of suppressing the peeling of the obtained image, and from the viewpoint of improving the abrasion resistance of the obtained image, in the specific polymer according to the present disclosure, the total content of the structural unit I, the structural unit II, and the structural unit III is It is preferably 20% by mass to 95% by mass, more preferably 35% by mass to 90% by mass, and still more preferably 50% by mass to 80% by mass, based on the total mass of the specific polymer. .

-Structural unit A-1-
The specific polymer according to the present disclosure is a structural unit represented by the following formula A-1 (hereinafter, also referred to as “structural unit A-1”) from the viewpoint of imparting an emulsifying and dispersing effect, which is rich in reactivity and simple in synthesis. ) Is preferable.
The structural unit A-1 can be introduced into a specific polymer by using, for example, a diol compound such as diethylene glycol or ethylene glycol as a monomer for obtaining the specific polymer.

In Formula A-1, R ^A1 represents a divalent linking group, and preferably represents an alkylene group, an arylene group, an alkylene group having one or more ether bonds in the structure, or a group represented by these bonds. .
In the present specification, unless otherwise specified, the `` alkylene group '' may be linear or branched, and some or all of the carbon atoms constituting the alkylene group have a cyclic structure. It may be formed.
The alkylene group is preferably an alkylene group having 2 to 20 carbon atoms, more preferably an alkylene group having 2 to 10 carbon atoms, and further preferably an alkylene group having 2 to 4 carbon atoms.
The arylene group is preferably an arylene group having 6 to 20 carbon atoms, more preferably an arylene group having 6 to 10 carbon atoms, and further preferably a phenylene group.

  The structural unit A-1 includes, for example, the following structural units, but is not limited thereto.

Examples of the structural unit A-1 include aliphatic diols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, butanediol, hexanediol, and neopentyl glycol; and lipids such as cyclohexanediol and hydrogenated bisphenol A. Cyclic diols; structural units derived from diols such as aromatic diols such as ethylene oxide adduct of bisphenol A and propylene oxide adduct of bisphenol A; The specific polymer may contain these structural units A-1 alone or in a combination of two or more.
Further, the specific polymer may further contain a structural unit derived from a trihydric or higher polyhydric alcohol (glycerin, trimethylolpropane, pentaerythritol).

  The specific polymer used in the present disclosure preferably contains the structural unit A-1 in an amount of 5% by mass to 80% by mass, more preferably 10% by mass to 65% by mass, based on the total mass of the specific polymer. , 20% by mass to 50% by mass.

-Structural unit A-2--
The specific polymer according to the present disclosure may contain a structural unit represented by the following formula A-2 (hereinafter, also referred to as “structural unit A-2”).
The structural unit A-2 can be introduced into the specific polymer by using, for example, a dicarboxylic acid ester compound such as methyl alkylenedicarboxylate as a monomer for obtaining the specific polymer.

In Formula A-2, R ^A2 represents a divalent linking group, and preferably represents an alkylene group, an arylene group, or a group represented by a bond thereof.
The alkylene group is preferably an alkylene group having 1 to 20 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and further preferably an alkylene group having 1 to 6 carbon atoms.
The arylene group is preferably an arylene group having 6 to 20 carbon atoms, more preferably an arylene group having 6 to 10 carbon atoms, and further preferably a phenylene group.

  The structural unit A-2 includes, for example, the following structural units, but is not limited thereto.

Examples of the structural unit A-2 include aromatic carboxylic acids such as terephthalic acid, isophthalic acid, phthalic anhydride, trimellitic anhydride, pyromellitic acid, and naphthalenedicarboxylic acid; maleic anhydride, fumaric acid, and succinic acid. And structural units derived from dicarboxylic acid compounds such as aliphatic carboxylic acids such as alkenyl succinic anhydride and adipic acid; and alicyclic carboxylic acids such as cyclohexanedicarboxylic acid. The specific polymer may contain these structural units A-2 alone or in a combination of two or more.
Further, the specific polymer may further contain a constituent unit derived from a carboxylic acid having a valency of 3 or more (such as trimellitic acid and its acid anhydride).

  The specific polymer used in the present disclosure preferably contains the structural unit A-2 in an amount of 5% by mass to 80% by mass, more preferably 10% by mass to 65% by mass, based on the total mass of the specific polymer. , 20% by mass to 50% by mass.

-Structural unit A-3-
The specific polymer according to the present disclosure may contain a structural unit represented by the following formula A-3 (hereinafter, also referred to as “structural unit A-3”).
The structural unit represented by Formula A-3 can be introduced into a specific polymer by using, for example, a diisocyanate compound such as hexamethylene diisocyanate as a monomer for obtaining the specific polymer.
The diisocyanate compound forms a specific polymer by, for example, reacting with a hydroxy group of another monomer to form a urethane bond, or reacting with an amino group of another monomer to form a urea bond.

In Formula A-3, R ^A3 represents a divalent linking group, and preferably represents an alkylene group, an arylene group, or a group represented by a bond thereof.
The alkylene group is preferably an alkylene group having 1 to 20 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and further preferably an alkylene group having 1 to 4 carbon atoms.
The arylene group is preferably an arylene group having 6 to 20 carbon atoms, more preferably an arylene group having 6 to 10 carbon atoms, and further preferably a phenylene group.
In formula A-3, the hydrogen atoms bonded to the two nitrogen atoms may be each independently substituted. Preferred substituents include alkyl groups.

  Examples of the structural unit A-3 include, but are not limited to, the following structural units.

  The specific polymer used in the present disclosure preferably contains 5% to 80% by mass, more preferably 10% to 65% by mass, of the structural unit A-3 based on the total mass of the specific polymer. , 20% by mass to 50% by mass.

-Structural unit A-4-
The specific polymer according to the present disclosure may contain a structural unit represented by the following formula A-4 (hereinafter, also referred to as “structural unit A-4”).
The structural unit represented by Formula A-4 can be introduced into a specific polymer by using, for example, a diamine compound such as hexamethylenediamine as a monomer for obtaining the specific polymer.
The above-mentioned diamine compound reacts with a carboxy group or a carboxylic acid ester structure of another monomer to form an amide bond, or reacts with an isocyanate group of another monomer to form a urea bond. Form coalescence.

In Formula A-4, R ^A4 represents a divalent linking group, and preferably represents an alkylene group, an arylene group, or a group represented by a bond thereof.
In Formula A-4, the hydrogen atoms bonded to the two nitrogen atoms may be each independently substituted. Preferred substituents include alkyl groups.
The alkylene group is preferably an alkylene group having 1 to 20 carbon atoms, more preferably an alkylene group having 1 to 10 carbon atoms, and further preferably an alkylene group having 1 to 4 carbon atoms.
The arylene group is preferably an arylene group having 6 to 20 carbon atoms, more preferably an arylene group having 6 to 10 carbon atoms, and further preferably a phenylene group.

  Examples of the structural unit A-4 include the following structural units, but are not limited thereto.

  The specific polymer used in the present disclosure preferably contains 5% to 80% by mass, more preferably 10% to 65% by mass, of the structural unit A-4 based on the total mass of the specific polymer. , 20% by mass to 50% by mass.

(Physical properties of specific polymer)
The specific polymer used in the present disclosure has a weight-average molecular weight of 1,000 to 500,000 from the viewpoint of suppressing detachment of the obtained image and facilitating viscosity removal in the removal step in the polymer production method. , Preferably 2,000 to 250,000, and more preferably 3,000 to 100,000.

The specific polymer used in the present disclosure preferably has a glass transition temperature (Tg) of 10C to 120C, more preferably 25C to 110C, and further preferably 50C to 100C. preferable.
In the present disclosure, the glass transition temperature of the resin can be measured using differential scanning calorimetry (DSC).
A specific measuring method is performed according to the method described in JIS K 7121 (1987) or JIS K 6240 (2011). As the glass transition temperature in this specification, an extrapolated glass transition start temperature (hereinafter, sometimes referred to as Tig) is used.
The method for measuring the glass transition temperature will be described more specifically.
When the glass transition temperature is determined, the temperature is held at about 50 ° C. lower than the expected Tg of the resin until the apparatus is stabilized, and then the heating rate is 20 ° C./min. Heat to an elevated temperature and generate a differential thermal analysis (DTA) curve or DSC curve.
The extrapolated glass transition onset temperature (Tig), that is, the glass transition temperature Tg in the present specification, is defined as a straight line obtained by extending the low-temperature-side baseline in the DTA curve or DSC curve to the high-temperature side, and a step change portion of the glass transition. Determined as the temperature at the intersection with the tangent drawn at the point where the slope of the curve is maximum.

Further, the specific polymer used in the present disclosure is preferably a water-soluble or water-dispersible polymer.
As used herein, “water-soluble” refers to a property that can be dissolved in water at a certain concentration or more. As “water-soluble”, a property of dissolving 5 g or more (more preferably 10 g or more) in 100 g of water at 25 ° C. is preferable.
In the present disclosure, “water-dispersible” means that a compound that is not water-soluble does not precipitate in water at 25 ° C. Specifically, the compound is dissolved in water State, a state in which micelles are formed in water, a state in which water is uniformly dispersed in water, and the like.

The specific polymer used in the present disclosure may be in any form such as a linear polymer, a graft polymer, a star polymer, and a network polymer, but is preferably a linear polymer. .
The linear polymer is obtained, for example, by reacting a diol compound, a dicarboxylic acid alkyl ester compound, and, if necessary, at least one of a diisocyanate compound and a diamine compound.

〔Concrete example〕
Hereinafter, specific examples of the specific polymer are shown, but the invention is not limited thereto.
In the following structural formulas, the subscripts in parentheses indicate the molar content.

〔Content〕
The pretreatment liquid for printing according to the present disclosure may contain the specific polymer in an amount of 1% by mass to 25% by mass with respect to the total mass of the pretreatment liquid for printing, from the viewpoint of suppressing peeling of an image from a printed material. The content is preferably 3% by mass to 15% by mass, more preferably 5% by mass to 10% by mass.

<Water>
The pretreatment liquid for printing according to the present disclosure includes water.
The water content is preferably from 50% by mass to 95% by mass, more preferably from 60% by mass to 90% by mass, and preferably from 70% by mass to 85% by mass, based on the total mass of the pretreatment liquid for printing. % Is more preferable.

<Coagulant>
The pretreatment liquid for printing according to the present disclosure preferably further includes at least one coagulant selected from the group consisting of a salt of a polyvalent metal compound, an organic acid, and a cationic compound.
Details of each component will be described later.
When the pretreatment liquid for printing contains a coagulant, an image having excellent image quality is easily obtained.
Further, by using the specific polymer and the coagulant used in the present disclosure in combination, the leakage of the coagulant in the obtained printed matter is suppressed, and the transfer of components contained in the pretreatment liquid for printing such as the coagulant is suppressed. It is thought to be done. The mechanism by which the transfer is suppressed is not clear, but is presumed to be because the affinity between the specific polymer and the flocculant is high, and in particular, the transfer of the flocculant is suppressed.

The pretreatment liquid for printing according to the present disclosure, the image quality of the obtained printed matter, and, from the viewpoint of suppressing the transfer of components contained in the pretreatment liquid for printing, the solid content of the specific polymer in the pretreatment liquid for printing, The mass ratio of the solid content of the flocculant is preferably from 100: 4 to 1: 3, more preferably from 100: 6 to 1: 2.5, based on the content of the specific polymer: the content of the flocculant. , And more preferably 10: 1 to 1: 2.
In the present disclosure, the solid content refers to the balance of each component excluding solvents such as water and organic solvents.

The coagulant used in the present disclosure preferably contains an organic acid from the viewpoint of the image quality and abrasion resistance of the obtained printed matter, and the organic acid preferably contains a dicarboxylic acid.
Hereinafter, details of the flocculant used in the present disclosure will be described.

(Organic acid)
Examples of the organic acid include an organic compound having an acidic group.
Examples of the acidic group include a phosphoric acid group, a phosphonic acid group, a phosphinic acid group, a sulfate group, a sulfonic acid group, a sulfinic acid group, and a carboxy group. The acidic group is preferably a phosphate group or a carboxy group, more preferably a carboxy group, from the viewpoint of the aggregation speed of the ink.
It is preferable that at least a part of the acidic group is dissociated in the pretreatment liquid for printing.

  Organic compounds having a carboxy group include polyacrylic acid, acetic acid, glycolic acid, malonic acid, malic acid (preferably DL-malic acid), maleic acid, ascorbic acid, succinic acid, glutaric acid, fumaric acid, citric acid, Tartaric acid, phthalic acid, 4-methylphthalic acid, lactic acid, sulfonic acid, orthophosphoric acid, pyrrolidonecarboxylic acid, pyronecarboxylic acid, pyrrolecarboxylic acid, furancarboxylic acid, pyridinecarboxylic acid, coumaric acid, thiophenecarboxylic acid, nicotinic acid, or these Or a salt thereof (eg, a polyvalent metal salt) and the like. These compounds may be used alone or in combination of two or more.

The organic compound having a carboxy group is preferably a divalent or higher carboxylic acid (hereinafter, also referred to as a polyvalent carboxylic acid), and more preferably a dicarboxylic acid, from the viewpoint of the aggregation speed of the ink.
As the dicarboxylic acid, malonic acid, malic acid, maleic acid, succinic acid, glutaric acid, fumaric acid, tartaric acid, 4-methylphthalic acid, or citric acid is more preferable, and malonic acid, malic acid, tartaric acid, or citric acid is preferable. .

The organic acid preferably has a low pKa (for example, 1.0 to 5.0).
As a result, the surface charge of particles such as pigments and polymer particles in the ink, which is dispersion-stabilized by a weakly acidic functional group such as a carboxy group, is reduced by contact with an organic acidic compound having a lower pKa. Can be reduced.

  The organic acid contained in the pretreatment liquid for printing preferably has a low pKa, a high solubility in water, a valence of 2 or more, and a functional group that stabilizes the dispersion of particles in the ink (for example, It is more preferable that the divalent or trivalent acidic substance has a high buffering capacity in a pH range lower than the pKa of the carboxy group or the like.

  When an organic acid is used as the coagulant, the content of the organic acid is preferably from 1% by mass to 20% by mass, and preferably from 2% by mass to 15% by mass, based on the total mass of the pretreatment liquid for printing according to the present disclosure. %, More preferably 5% by mass to 10% by mass.

(Salt of polyvalent metal compound)
The salt of the polyvalent metal compound is composed of a divalent or higher polyvalent metal ion and an anion bonded to the polyvalent metal ion. Further, the salt of the polyvalent metal compound is preferably water-soluble.
Specific examples of polyvalent metal ions include divalent metal ions such as Ca ²⁺ , Cu ²⁺ , Ni ²⁺ , Mg ²⁺ , Zn ²⁺ , and Ba ^2+, and trivalent metal ions such as Al ³⁺ , Fe ³⁺ , and Cr ^3+. Can be Examples of the anion include Cl ⁻ , NO ₃ ⁻ , I ⁻ , Br ⁻ , ClO ₃ ⁻ , SO ₄ ²⁻ , and a carboxylate ion.

As the salt of the polyvalent metal compound, a salt containing Ca ²⁺ or Mg ²⁺ is preferable from the viewpoint of the image quality of the obtained printed matter.

The salt of the polyvalent metal compound includes a sulfate ion (SO ₄ ²⁻ ), a nitrate ion (NO ₃ ⁻ ) or a carboxylate ion (RCOO ⁻ , where R is an alkyl group having 1 or more carbon atoms). Salts are preferred.

Here, the carboxylate ion is preferably derived from a saturated aliphatic monocarboxylic acid having 1 to 6 carbon atoms or a carbocyclic monocarboxylic acid having 7 to 11 carbon atoms. Preferred examples of the saturated aliphatic monocarboxylic acid having 1 to 6 carbon atoms include formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, hexanoic acid and the like. Particularly, formic acid and acetic acid are preferable.

  When a polyvalent metal compound is used as the aggregating agent, the content of the polyvalent metal compound is preferably from 1% by mass to 40% by mass relative to the total mass of the pretreatment liquid for printing according to the present disclosure, and is preferably 2% by mass. % To 25% by mass, and still more preferably 5% to 20% by mass.

(Cationic compound)
As the cationic compound, a cationic surfactant is preferably exemplified. As the cationic surfactant, for example, a primary, secondary, or tertiary amine salt type compound is preferable. Examples of the amine salt type compound include compounds such as hydrochloride and acetate (eg, laurylamine, cocoamine, stearylamine, rosinamine, etc.) and quaternary ammonium salt type compounds (eg, lauryltrimethylammonium chloride, cetyltrimethyl) Ammonium chloride, lauryldimethylbenzylammonium chloride, benzyltributylammonium chloride, benzalkonium chloride, etc.), pyridinium salt type compounds (eg, cetylpyridinium chloride, cetylpyridinium bromide, etc.), imidazoline type cationic compounds (eg, 2-heptadecenyl- Hydroxyethylimidazoline), ethylene oxide adducts of higher alkylamines (eg, dihydroxyethylstearylamine). It can gel. Further, polyallylamines may be used. In addition to these, it may be used also amphoteric surfactants exhibiting cationic at the desired pH range, for example, amino acid type amphoteric _{surfactants, R-NH-CH 2 CH} 2 -COOH type compounds (R is an alkyl Groups, etc.), carboxylate type amphoteric surfactants (eg, stearyl dimethyl betaine, lauryl dihydroxyethyl betaine, etc.), sulfate type, sulfonic acid type, and phosphate type amphoteric surfactants, etc. No.

  The polyallylamine or polyallylamine derivative is not particularly limited and may be appropriately selected from known ones. Examples thereof include polyallylamine hydrochloride, polyallylamine amide sulfate, allylamine hydrochloride / diallylamine hydrochloride copolymer, and allylamine. Acetate / diallylamine acetate copolymer, allylamine acetate / diallylamine acetate copolymer, allylamine hydrochloride / dimethylallylamine hydrochloride copolymer, allylamine / dimethylallylamine copolymer, polydiallylamine hydrochloride, polymethyldiallylamine hydrochloride, polymethyldiallylamine amide sulfate , Polymethyldiallylamine acetate, polydiallyldimethylammonium chloride, diallylamine acetate / sulfur dioxide copolymer, diallylmethylethyl Nmo bromide Ethyl Sulfate-sulfur dioxide copolymer, methyl diallyl amine hydrochloride-sulfur dioxide copolymers, diallyldimethylammonium chloride-sulfur dioxide copolymers, diallyldimethylammonium chloride-acrylamide copolymer and the like.

  As such a polyallylamine or a polyallylamine derivative, a commercially available product can be used. For example, "PAA-HCL-01", "PAA-HCL-03", "PAA-HCL-05", "PAA- HCL-3L, "PAA-HCL-10L", "PAA-H-HCL", "PAA-SA", "PAA-01", "PAA-03", "PAA-05", "PAA-08" , "PAA-15", "PAA-15C", "PAA-25", "PAA-H-10C", "PAA-D11-HCL", "PAA-D41-HCL", "PAA-D19-HCL" , "PAS-21CL", "PAS-M-1L", "PAS-M-1", "PAS-22SA", "PAS-M-1A", "PAS-H-1L", "PAS-H-" 5L ”,“ PA -H-10L "," PAS-92 "," PAS-92A "," PAS-J-81L "," PAS-J-81 "(trade name, manufactured by Nitto Boseki Co., Ltd.)," Himo Neo-600 " , "HIMOLOCK Q-101", "HIMOLOCK Q-311", "HIMOLOCK Q-501", "HIMAX SC-505", "HIMAX SC-505" (trade name, manufactured by Himo Corporation), etc. Can be.

  When a cationic compound is used as the coagulant, the content of the cationic compound is preferably from 1% by mass to 40% by mass, and more preferably from 2% by mass, based on the total mass of the pretreatment liquid for printing according to the present disclosure. The content is more preferably 25% by mass, and still more preferably 5% by mass to 20% by mass.

-Water-soluble polymer compound-
The pretreatment liquid for printing may contain a water-soluble polymer compound.
The water-soluble polymer compound is not particularly limited, and a known water-soluble polymer compound such as polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, and polyethylene glycol can be used.
Further, as the water-soluble polymer compound, a specific polymer compound described later and a water-soluble polymer compound described in paragraphs 0026 to 0080 of JP-A-2013-001854 are also suitable.

  The weight average molecular weight of the water-soluble polymer compound is not particularly limited, but may be, for example, 10,000 to 100,000, preferably 20,000 to 80,000, and more preferably 30,000 to 80,000. 80,000.

Further, the content of the water-soluble polymer compound in the pretreatment liquid for printing is not particularly limited, but is preferably 0.1% by mass to 10% by mass, and more preferably 0.1% by mass to the total amount of the pretreatment liquid for printing. It is more preferably from 4% by mass to 4% by mass, further preferably from 0.1% by mass to 2% by mass, further preferably from 0.1% by mass to 1% by mass.
When the content is 0.1% by mass or more, the spread of the ink droplets can be further promoted, and when the content is 10% by mass or less, the viscosity increase of the pretreatment liquid for printing can be further suppressed. Further, when the content is 10% by mass or less, coating unevenness of the pretreatment liquid for printing caused by bubbles in the pretreatment liquid for printing can be further suppressed.

As the water-soluble polymer compound, a polymer compound containing a hydrophilic structural unit having an ionic group (preferably an anionic group) (hereinafter, also referred to as “specific polymer compound”) is preferable. Thereby, the spread of the ink droplets applied to the base material can be further promoted, and the roughness of the image is further suppressed.
Examples of the ionic group in the specific polymer compound include a carboxy group, a sulfonic acid group, a phosphoric acid group, a boronic acid group, an amino group, a quaternary ammonium group, and salts thereof. Among them, preferably, a carboxy group, a sulfonic acid group, a phosphate group, or a salt thereof, more preferably, a carboxy group, a sulfonic acid group, or a salt thereof, further preferably, a sulfonic acid group or a salt thereof. Salt.
As the hydrophilic structural unit having an ionic group (preferably an anionic group), a structural unit derived from a (meth) acrylamide compound having an ionic group (preferably an anionic group) is preferable.
The content of the hydrophilic structural unit having an ionic group (preferably an anionic group) in the water-soluble polymer compound is, for example, 10% by mass to 100% by mass in the total mass of the water-soluble polymer compound. It is preferably 10% to 90% by mass, more preferably 10% to 70% by mass, still more preferably 10% to 50% by mass, and more preferably 20% to 40% by mass. More preferably, it is mass%.

The specific polymer compound includes at least one hydrophilic structural unit having the above-mentioned ionic group (preferably an anionic group, particularly preferably a sulfonic acid group) and at least one hydrophobic structural unit. Is more preferable. By containing the hydrophobic structural unit, the specific polymer compound is more likely to be present on the surface of the pretreatment liquid for printing, so that the spread of ink droplets applied to the base material is further promoted, and the roughness of the image is further suppressed. Is done.
As the hydrophobic structural unit, a structural unit derived from a (meth) acrylic acid ester (preferably, an alkyl ester of (meth) acrylic acid having 1 to 4 carbon atoms) is preferable.

  The content of the hydrophobic structural unit in the specific polymer compound may be, for example, 10% by mass to 90% by mass, and preferably 30% by mass to 90% by mass in the total mass of the specific polymer compound. , 50 mass% to 90 mass%, more preferably 60 mass% to 80 mass%.

-Water-soluble solvent-
The pretreatment liquid for printing preferably contains at least one water-soluble solvent.
Known water-soluble solvents can be used without any particular limitation.
Examples of the water-soluble solvent include glycols such as glycerin, 1,2,6-hexanetriol, trimethylolpropane, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, and dipropylene glycol. 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 2-methyl-2,4-pentanediol, 1,2-octanediol, 1,2-hexanediol, 1,2; Polyhydric alcohols such as alkanediols such as -pentanediol and 4-methyl-1,2-pentanediol; saccharides, sugar alcohols, hyaluronic acids, and carbon atoms described in paragraph 0116 of JP-A-2011-42150. Alkyl alcohol of formulas 1-4 S, glycol ethers, 2-pyrrolidone, N- methyl-2-pyrrolidone; and the like.
Among them, polyalkylene glycol or a derivative thereof is preferable from the viewpoint of suppressing image peeling, and diethylene glycol monoalkyl ether, triethylene glycol monoalkyl ether, dipropylene glycol, tripropylene glycol monoalkyl ether, and polyoxypropylene glyceryl are preferable. More preferably, it is at least one selected from ether and polyoxyethylene polyoxypropylene glycol.

  The content of the water-soluble solvent in the pretreatment liquid for printing is preferably from 3% by mass to 20% by mass, and more preferably from 5% by mass to 15% by mass, from the viewpoint of applicability and the like. % Is more preferable.

-Surfactant-
The pretreatment liquid for printing may contain at least one surfactant.
Surfactants can be used as surface tension modifiers or defoamers. Nonionic surfactants, cationic surfactants, anionic surfactants, betaine surfactants, etc., are examples of the surface tension modifier or defoaming agent. Among them, a nonionic surfactant or an anionic surfactant is preferable from the viewpoint of the aggregation speed of the ink.

  Examples of the surfactant include JP-A-59-157636, pages 37 to 38 and Research Disclosure No. 308119 (1989) as a surfactant. Further, fluorine (alkyl fluoride) -based surfactants and silicone-based surfactants described in JP-A-2003-322926, JP-A-2004-325707, and JP-A-2004-309806 can also be used.

  The content of the surfactant in the pretreatment liquid for printing is not particularly limited, but is preferably such that the surface tension of the pretreatment liquid for printing becomes 50 mN / m or less, and 20 mN / m to 50 mN. / M, more preferably 30 mN / m to 45 mN / m.

-Other additives-
The pretreatment liquid for printing may contain other components other than the above as needed.
Other components that can be contained in the pretreatment liquid for printing include solid wetting agents, colloidal silica, inorganic salts, anti-fading agents, emulsion stabilizers, penetration enhancers, ultraviolet absorbers, preservatives, fungicides, pH adjustment Well-known additives such as an agent, a viscosity modifier, a rust preventive, and a chelating agent.

-Physical properties of pretreatment liquid for printing-
The pretreatment liquid for printing preferably has a pH at 25 ° C. of 0.1 to 3.5 from the viewpoint of the aggregation rate of the ink.
When the pH of the printing pretreatment liquid is 0.1 or more, the roughness of the substrate is further reduced, and the adhesion of the image area is further improved.
When the pH of the pretreatment liquid for printing is 3.5 or less, the aggregation speed is further improved, coalescence of dots (ink dots) by the ink on the base material is further suppressed, and the roughness of the image is further reduced. .
The pH (25 ° C.) of the pretreatment liquid for printing is more preferably from 0.2 to 2.0.

  The viscosity of the pretreatment liquid for printing is preferably from 0.5 mPa · s to 10 mPa · s, more preferably from 1 mPa · s to 5 mPa · s, from the viewpoint of the aggregation speed of the ink. The viscosity is measured using VISCOMMETER TV-22 (manufactured by Toki Sangyo Co., Ltd.) at 25 ° C.

  The surface tension of the pretreatment liquid for printing at 25 ° C. is preferably 60 mN / m or less, more preferably 20 mN / m to 50 mN / m, and further preferably 30 mN / m to 45 mN / m. preferable. When the surface tension of the printing pretreatment liquid is within the range, the adhesion between the base material and the printing pretreatment liquid is improved. The surface tension of the printing pretreatment liquid is measured by a plate method using an Automatic Surface Tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.).

(Printing substrate)
The printing substrate according to the present disclosure includes a non-permeable medium and a solidified product containing a polymer containing the structural unit I represented by the above formula I.

<Non-permeable medium>
The “non-permeable” of the non-permeable medium used in the present disclosure means that the water contained in the ink composition has little or no absorption, and specifically, the water absorption is 10.0 g / water. m ² refers to the nature is less.
The amount of water absorbed by the non-permeable medium was absorbed by holding the water in contact with an area of 100 mm × 100 mm on the image recording surface of the non-permeable medium at 25 ° C. for 1 minute. It is obtained by calculating the mass of water and calculating the amount of absorption per unit area.

The non-permeable medium used in the present disclosure is not particularly limited, and examples thereof include a sheet-like medium and a film-like medium.
The non-permeable medium used in the present disclosure is preferably a non-permeable medium that can be formed into a roll by winding a sheet-shaped or film-shaped non-permeable medium from the viewpoint of productivity of printed matter.

Examples of non-permeable media include metal plates (eg, aluminum, zinc, copper, etc.) and plastic films (eg, polyvinyl chloride resin, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate) , Cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), art paper, coated paper and the like.
Above all, a medium containing a thermoplastic resin such as polyvinyl chloride, polyethylene terephthalate, and polyethylene is preferable.
The non-permeable medium may be surface-treated.
Examples of the surface treatment include, but are not limited to, corona treatment, plasma treatment, flame treatment, heat treatment, abrasion treatment, light irradiation treatment (UV treatment), and flame treatment. For example, if the surface of the non-permeable medium is subjected to corona treatment before the ink is applied and the image is recorded, the surface energy of the non-permeable medium increases, and the surface of the non-permeable medium becomes wet and non-permeable. Adhesion of the ink to the volatile medium is promoted. The corona treatment can be performed using, for example, a corona master (manufactured by Shinko Electric Meter Co., Ltd., PS-10S). The conditions of the corona treatment may be appropriately selected depending on the case, such as the type of the non-permeable medium and the composition of the ink. For example, the following processing conditions may be used.
Processing voltage: 10 kV to 15.6 kV
・ Processing speed: 30 mm / s to 100 mm / s

<Solidified material>
The printing substrate according to the present disclosure includes a solidified material. The solidified material may be included in at least a part of the surface to be printed of the printing substrate, and may be included in an aspect included in the entire surface of the surface to be printed or in a portion excluding an edge of the surface to be printed. Included embodiments and the like.
When the non-penetrable medium is in the form of a sheet or a film, the solidified material may be contained on one side of the non-penetrable medium or on both sides.
Further, the solidified material is preferably in a layered form on a non-permeable substrate.
That is, the printing substrate according to the present disclosure preferably has a layer containing a solidified material on at least one surface of the non-permeable substrate.
The layer containing the solidified material is preferably a layer made of the solidified material.
Further, in the present disclosure, the layer containing the solidified material or the layer made of the solidified material may be a continuous layer, a discontinuous layer, or a layer having a non-uniform thickness.
The thickness of the layer containing the solidified material is preferably from 0.01 μm to 10 μm, and more preferably from 0.05 μm to 1 μm.
The thickness is measured by cutting a printing substrate and observing the cut surface with a scanning electron microscope. As a method for measuring the thickness, after cooling the sample with liquid nitrogen, the sample is sectioned using a microtome, and the thickness of the cross-sectional portion is measured by a method such as calculating the average thickness at five locations.

The polymer contained in the solidified product and containing the structural unit I represented by the above formula I has the same meaning as the specific polymer according to the present disclosure, and preferred embodiments are also the same.
Further, the solidified product does not contain water, or the content of water is more than 0% by mass and 20% by mass or less based on the total mass of the solidified product. It is preferable that the amount is more than 0% by mass and 5% by mass or less based on the total mass of the solidified product.
The measurement of the water content is performed by the following Karl Fischer measurement method or the like.
The water content (mg) was measured using a Karl Fischer titrator (CA-06 type coulometric titration moisture meter manufactured by Mitsubishi Kasei), and the water content (%) was calculated by the following formula (A). Note that the measurement sample indicates a sample obtained by taking out only the solidified material from the base material.
Water content (%) = [moisture content (mg) / measurement sample (mg)] × 100 Formula (A)
Detailed conditions for the measurement conformed to JIS K0113: 2005.
The solidified product is obtained, for example, by drying the pretreatment liquid for printing according to the present disclosure.
The drying means removing at least a part of water contained in the pretreatment liquid for printing. The drying method is not particularly limited, and examples thereof include drying by heating, drying by blowing, and natural drying.

Further, it is preferable that the solidified material contains a flocculant.
The flocculant contained in the solidified product has the same meaning as the flocculant contained in the above-described pretreatment liquid for printing according to the present disclosure, and the preferred embodiment is also the same.

Further, the solidified product may contain a water-soluble polymer compound, a surfactant, and other additives.
The water-soluble polymer compound, surfactant, and other additives contained in the solidified product are the water-soluble polymer compound, surfactant, and the pre-treatment liquid for printing according to the present disclosure described above. It has the same meaning as the other additives, and the preferred embodiment is also the same.

The amount of solidified product in the printing substrate, from the viewpoint of suppressing the peeling of the image, preferably an amount that the amount of the specific polymer becomes ^{0.1g / m 2 ~3.0g / m 2} , 0.3g / m ^An amount of ^{2 to} 2.0 g / m ² is more preferable.

<Production method of printing substrate>
The method for producing a printing substrate according to the present disclosure includes a pretreatment step of applying the printing pretreatment liquid according to the present disclosure onto a non-permeable medium.

(Pretreatment step of pretreatment liquid for printing)
The application of the pretreatment liquid for printing in the pretreatment step can be performed by applying a known method such as a coating method, an inkjet method, and an immersion method. The coating method can be performed by a known coating method using a bar coater, an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, a bar coater, or the like. The details of the ink jet method are the same as those of the ink jet method in the image recording step described later.

(Drying step of printing pretreatment liquid)
Drying of the pretreatment liquid for printing may be drying by heating, drying by air blowing, or natural drying, but is preferably drying by heating.
Examples of the means for heating and drying include known heating means such as a heater, known air blowing means such as a dryer, and means combining these.
As a method for heating and drying an image, for example, a method in which heat is applied by a heater or the like from the side opposite to the surface of the non-permeable medium to which the printing pretreatment liquid is applied, Examples thereof include a method of blowing air or hot air, a method of applying heat with an infrared heater from the coated surface of the recording medium or the side opposite to the coated surface, a method of combining a plurality of these methods, and the like.

The heating temperature during heating and drying is preferably 60 ° C. or higher, more preferably 65 ° C. or higher, and particularly preferably 70 ° C. or higher.
The upper limit of the heating temperature is not particularly limited, but the upper limit is, for example, 100 ° C, preferably 90 ° C.

(Ink set)
An ink set according to the present disclosure includes an ink composition including a colorant and water, and a pretreatment liquid for printing according to the present disclosure.
For example, an ink set including an ink composition of four colors of cyan, magenta, yellow, and black and the pretreatment liquid for printing according to the present disclosure may be used.
Hereinafter, details of the ink composition included in the ink set used in the present disclosure will be described.

(Ink composition)
Hereinafter, the ink composition used in the present disclosure will be described.
The ink composition used in the present disclosure includes a colorant and water, and is preferably an aqueous ink composition. In the present disclosure, the aqueous ink composition refers to an ink composition containing water in an amount of 50% by mass or more based on the total mass of the ink.
Further, the content of the organic solvent in the ink composition according to the present disclosure is preferably 40% by mass or less, more preferably 30% by mass or less, based on the total mass of the ink composition.
Furthermore, the ink composition according to the present disclosure preferably does not contain a polymerizable compound, or the content of the polymerizable compound is more than 0% by mass and 10% by mass or less, and more preferably contains no polymerizable compound. preferable.
Examples of the polymerizable compound include a cationic polymerizable compound and a radical polymerizable compound.

-Coloring agent-
The colorant is not particularly limited, and a known colorant in the field of inkjet ink can be used, but an organic pigment or an inorganic pigment is preferable.

Examples of the organic pigment include an azo pigment, a polycyclic pigment, a dye chelate, a nitro pigment, a nitroso pigment, and aniline black. Among these, azo pigments and polycyclic pigments are more preferred.
Examples of the inorganic pigment include titanium oxide, iron oxide, calcium carbonate, barium sulfate, aluminum hydroxide, barium yellow, cadmium red, chrome yellow, and carbon black. Among these, carbon black is particularly preferred.
Preferable examples of the coloring agent include the coloring agents described in paragraphs 0096 to 0100 of JP-A-2009-241586.

  The content of the coloring agent is preferably 1% by mass to 25% by mass, more preferably 2% by mass to 20% by mass, still more preferably 5% by mass to 20% by mass, based on the total mass of the ink composition. 5% by mass to 15% by mass is particularly preferred.

−Water−
The ink composition contains water.
The water content is preferably from 50% by mass to 90% by mass, more preferably from 60% by mass to 80% by mass, based on the total mass of the ink composition.

-Dispersant-
The ink composition used in the present disclosure may contain a dispersant for dispersing the colorant. The dispersant may be either a polymer dispersant or a low molecular surfactant type dispersant. Further, the polymer dispersant may be either a water-soluble dispersant or a water-insoluble dispersant.
Preferred examples of the dispersant include the dispersants described in paragraphs 0080 to 0096 of JP-A-2006-145312.

  The mixing mass ratio (p: s) of the colorant (p) and the dispersant (s) is preferably in the range of 1: 0.06 to 1: 3, and more preferably in the range of 1: 0.125 to 1: 2. More preferably, it is 1: 0.125 to 1: 1.5.

-Resin particles-
The ink composition according to the present disclosure preferably contains at least one kind of resin particles. By containing the resin particles, it is possible to mainly improve the fixability of the ink composition to the recording medium (base material) and the abrasion resistance. In addition, the resin particles have a function of fixing the ink composition, that is, the image by causing aggregation or dispersion instability when the resin particles come into contact with the above-described coagulant to increase the viscosity of the ink composition. Such resin particles are preferably dispersed in water and a water-containing organic solvent.
Preferred examples of the resin particles include resin particles described in paragraphs 0062 to 0076 of JP-A-2006-188345.

-Water-soluble organic solvent-
The ink composition used in the present disclosure preferably contains at least one water-soluble organic solvent. The water-soluble organic solvent can provide an effect of preventing drying or wetting. To prevent drying, it is used as an anti-drying agent to prevent the ink from adhering and drying to form aggregates at the ink discharge ports of the ejection nozzles and to prevent clogging. Water-soluble organic solvents are preferred.

Preferably, the drying inhibitor is a water-soluble organic solvent having a lower vapor pressure than water. Specific examples of such a water-soluble organic solvent include ethylene glycol, propylene glycol, diethylene glycol, polyethylene glycol, thiodiglycol, dithiodiglycol, 2-methyl-1,3-propanediol, and 1,2,6-hexane. And polyhydric alcohols represented by triol, acetylene glycol derivatives, glycerin, trimethylolpropane and the like.
Among them, polyhydric alcohols such as glycerin and diethylene glycol are preferable as the anti-drying agent.
The drying inhibitors may be used alone or in combination of two or more. The content of the drying inhibitor is preferably in the range of 10 to 50% by mass in the ink composition.

  The water-soluble organic solvent is used for adjusting the viscosity in addition to the above. Specific examples of the water-soluble organic solvent that can be used for adjusting the viscosity include alcohols (for example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, sec-butanol, t-butanol, pentanol, hexanol, and cyclohexanol). , Benzyl alcohol), polyhydric alcohols (for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodithiol) Glycol), glycol derivatives (eg, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether) , Ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol diacetate, ethylene glycol monomethyl ether acetate, tri Ethylene glycol monomethyl ether, triethylene glycol monoethyl ether, ethylene glycol monophenyl ether), amine (for example, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethyl) Diamine, diethylenetriamine, triethylenetetramine, polyethyleneimine, tetramethylpropylenediamine) and other polar solvents (e.g., formamide, N, N-dimethylformamide, N, N-dimethylacetamide, dimethylsulfoxide, sulfolane, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, acetonitrile, acetone). Also in this case, the water-soluble organic solvent may be used alone or in combination of two or more.

-Other additives-
The ink composition used in the present disclosure can be configured using other additives in addition to the above components. Other additives include, for example, anti-drying agents (wetting agents), anti-fading agents, emulsion stabilizers, penetration enhancers, ultraviolet absorbers, preservatives, fungicides, pH adjusters, surface tension agents other than those described above. Known additives such as a regulator, an antifoaming agent, a viscosity regulator, a dispersant other than those described above, a dispersion stabilizer, a rust inhibitor, a chelating agent and the like can be mentioned.

(Image recording method)
The image recording method according to the present disclosure includes a pretreatment step of applying the printing pretreatment liquid according to the present disclosure to a non-permeable medium, and a colorant and water on the surface to which the printing pretreatment liquid is applied. And an image recording step of recording an image by discharging an ink composition containing the same by an inkjet method.

<Pretreatment step>
The application of the pretreatment liquid for printing in the pretreatment step can be performed by applying a known method such as a coating method, an inkjet method, and an immersion method. The coating method can be performed by a known coating method using a bar coater, an extrusion die coater, an air doctor coater, a blade coater, a rod coater, a knife coater, a squeeze coater, a reverse roll coater, a bar coater, or the like. The details of the ink jet method are the same as those of the ink jet method in the image recording step described later.

The amount of the pretreatment liquid for printing is not particularly limited as long as the ink can be aggregated, but from the viewpoint of suppressing image peeling, the amount of the pretreatment liquid for printing after drying is 0.05 g / m 2. preferably the amount to be ² or more, amount of the applied after drying of 0.05 g ^/ m 2 to 1.0 g / ^{m 2} of the printing pretreatment liquid is more preferred.

Further, in the pretreatment step, the non-permeable medium may be heated before applying the printing pretreatment liquid.
The heating temperature may be appropriately set according to the type of the non-permeable medium and the composition of the pretreatment liquid for printing, but the temperature of the non-permeable medium is preferably 30 ° C to 70 ° C, and more preferably 30 ° C to The temperature is more preferably set to 60 ° C.

As the non-permeable medium used in the image recording method according to the present disclosure, a surface-treated medium may be used, or a non-permeable medium that has not been subjected to a surface treatment may be used in the pre-processing step before printing. Before applying the treatment liquid, a surface treatment of the non-permeable medium may be performed.
Examples of the surface treatment include the treatment described as the surface treatment of the impermeable medium in the printing substrate according to the present disclosure, and these treatments can be performed by a known method.

<Image recording process>
An image recording method according to an embodiment of the present disclosure is directed to an image recording method in which an ink composition containing a colorant and water is ejected onto a surface of the non-permeable medium to which the printing pretreatment liquid has been applied by an inkjet method to record an image. Process.
The image recording step is a step of applying the ink composition to a non-permeable medium by an inkjet method.
In this step, ink can be selectively applied to the non-permeable medium, and a desired visible image can be formed.
As the ink composition used in the image recording step, the above-described ink composition included in the ink set according to the present disclosure is suitably used.

  In image formation by an ink-jet method, by applying energy, ink is discharged onto a desired non-permeable medium to form a colored image. In addition, as a preferable inkjet method for the present disclosure, a method described in paragraph numbers 0093 to 0105 of JP-A-2003-306623 can be applied.

  The inkjet method is not particularly limited, and is a known method, for example, a charge control method for discharging ink using electrostatic attraction, a drop-on-demand method using a vibration pressure of a piezo element (pressure pulse method), An acoustic ink jet system that irradiates an ink by converting an electric signal into an acoustic beam and discharges the ink using radiation pressure, and a thermal ink jet (bubble jet (registered) that heats the ink to form bubbles and uses the generated pressure Trademark)) method or the like. As the ink-jet method, in particular, a method described in JP-A-54-59936 discloses a method in which an ink that has been subjected to the action of thermal energy causes a sudden volume change, and the ink is ejected from a nozzle by the action force resulting from this state change. It is possible to effectively utilize the ink jet method.

  As the inkjet head, a short serial head is used, and a shuttle system that performs printing while scanning the head in the width direction of the non-permeable medium, and printing elements are arranged corresponding to the entire area of one side of the non-permeable medium. And a line system using a line head. In the line system, the image can be recorded on the entire surface of the non-permeable medium by scanning the non-permeable medium in a direction intersecting the arrangement direction of the recording elements, and a transport system such as a carriage for scanning a short head is unnecessary. Becomes Further, complicated scanning control between the movement of the carriage and the non-permeable medium is not required, and only the non-permeable medium moves, so that a higher recording speed can be realized as compared with the shuttle method. The image recording method according to the present disclosure can be applied to any of these, but when applied to a line method that does not use a dummy jet, the effect of improving the ejection accuracy and the abrasion resistance of the image is large.

  The amount of ink droplets ejected from the inkjet head is preferably 1 pl (picoliter) to 10 pl, and more preferably 1.5 pl to 6 pl from the viewpoint of obtaining a high-definition image. In addition, from the viewpoint of improving the unevenness of the image and the connection of the continuous gradation, it is also effective to discharge different liquid proper amounts in combination.

<Drying process>
The image recording method according to the present disclosure may include a drying step.
The drying step can be performed at one or both timings after the pre-processing step, before the image recording step, and after the image recording step.
As the drying, heat drying is preferable.
Examples of the means for heating and drying an image include a known heating means such as a heater, a known air blowing means such as a dryer, and a combination thereof.
Examples of the method for heating and drying the image include, for example, a method of applying heat with a heater or the like from the side opposite to the image forming surface of the non-permeable medium, a method of applying hot air or hot air to the image forming surface of the recording medium, From the image forming surface of the recording medium or the side opposite to the image forming surface, a method of applying heat with an infrared heater, a method of combining a plurality of these methods, and the like can be used.

The heating temperature at the time of heating and drying the image is preferably 60 ° C. or higher, more preferably 65 ° C. or higher, and particularly preferably 70 ° C. or higher.
The upper limit of the heating temperature is not particularly limited, but the upper limit is, for example, 100 ° C, preferably 90 ° C.
The time for heating and drying the image is not particularly limited, but is preferably 3 seconds to 60 seconds, more preferably 5 seconds to 30 seconds, and particularly preferably 5 seconds to 20 seconds.

(Another Embodiment of Image Recording Method)
Further, another embodiment of the image recording method according to the present disclosure is directed to a method of printing an ink composition containing a colorant and water on a surface of a printing substrate according to the present disclosure to which the pretreatment liquid for printing is applied. And an image recording step of recording an image by discharging the image.
The image recording step is synonymous with the image recording step in the above-described image recording method, and the preferred embodiment is also the same.
Further, another aspect of the image recording method may include a drying step. The details of the drying step are the same as the drying step in the above-described image recording method, and the preferred embodiments are also the same.

<Inkjet recording device>
There is no particular limitation on the image forming apparatus that can be used in the image recording method according to the present disclosure, and the image forming apparatus described in JP-A-2010-83021, JP-A-2009-234221, JP-A-10-175315, and the like are described. A known image forming apparatus can be used.

Hereinafter, an example of an image forming apparatus that can be used in the image recording method according to the present disclosure will be described with reference to FIG.
Next, an example of an inkjet recording apparatus suitable for performing the image recording method according to the present disclosure will be specifically described with reference to FIG.
FIG. 1 is a schematic configuration diagram illustrating a configuration example of the entire inkjet recording apparatus.

  As shown in FIG. 1, the ink jet recording apparatus includes an anilox roller 20 as a roller material for applying a pretreatment liquid for printing sequentially from a supply section 11 of a non-permeable medium in a conveying direction (the direction of an arrow in the figure). And a printing pretreatment liquid application section 12 having an application roller 22 abutting thereon, a printing pretreatment liquid drying zone 13 having a heating means (not shown) for drying the applied printing pretreatment liquid, and And an ink discharge section 14 for discharging various inks, and an ink drying zone 15 for drying the discharged ink.

  The recording medium supplied to the ink jet recording apparatus is supplied from a supply unit that supplies the recording medium from a case where the recording medium is loaded, a supply unit that supplies the recording medium from a roll around which the recording medium is wound in a roll shape, and the like. From the unit 11, the printing pretreatment liquid application unit 12, the printing pretreatment liquid drying zone 13, the ink discharge unit 14, and the ink drying zone 15 are sequentially sent by the conveyance rollers 41, 42, 43, 44, 45, and 46. And is accumulated in the accumulation section. In the stacking unit 16, the recording medium may be wound in a roll shape. The transfer may be performed by a method using a transfer roller, a drum transfer method using a drum-shaped member, a belt transfer method, a stage transfer method using a stage, or the like.

  At least one of the plurality of transport rollers 41, 42, 43, 44, 45, 46 may be a drive roller to which the power of a motor (not shown) is transmitted. The recording medium is conveyed in a predetermined direction by a predetermined conveyance amount by rotating a drive roller rotated by a motor at a constant speed.

The printing pretreatment liquid application unit 12 includes an anilox roller 20 that is disposed by immersing a part in a storage dish in which the printing pretreatment liquid is stored, an application roller 22 that is in contact with the anilox roller 20, and Is provided. The anilox roller 20 is a roller material for supplying a predetermined amount of the pretreatment liquid for printing to the application roller 22 arranged opposite to the recording surface of the recording medium. The printing pretreatment liquid is uniformly applied onto the recording medium by the application roller 22 supplied with an appropriate amount from the anilox roller 20.
The application roller 22 is configured to be able to convey the recording medium in a pair with the opposing roller 24, and the recording medium passes through the space between the application roller 22 and the opposing roller 24 to the printing pretreatment liquid drying zone 13. Sent.

  A printing pretreatment liquid drying zone 13 is disposed downstream of the printing pretreatment liquid application unit 12 in the recording medium transport direction. The printing pretreatment liquid drying zone 13 can be configured using a known heating means such as a heater, a blowing means using a blower such as a dryer, or a combination thereof. The heating unit is provided with a heating element such as a heater on the opposite side of the recording medium from the surface where the pretreatment liquid for printing is applied (for example, when the recording medium is automatically transported, below a transport mechanism that places and transports the recording medium). Examples thereof include a method, a method in which warm air or hot air is applied to the surface of the recording medium to which the printing pretreatment liquid is applied, a heating method using an infrared heater, and the like.

In addition, since the surface temperature of the recording medium changes depending on the type (material, thickness, etc.) of the recording medium, the environmental temperature, and the like, the measurement unit that measures the surface temperature of the recording medium and the surface temperature of the recording medium measured by the measurement unit It is preferable to provide a control mechanism for feeding back the value of (1) to the heating control unit and apply the pretreatment liquid for printing while controlling the temperature. As a measuring unit for measuring the surface temperature of the recording medium, a contact or non-contact thermometer is preferable.
Further, the solvent may be removed using a solvent removing roller or the like. As another embodiment, a method of removing excess solvent from a recording medium with an air knife is also used.

The ink discharge unit 14 is disposed downstream of the printing pretreatment liquid drying zone 13 in the recording medium transport direction. Each of the ink storage units that store each color ink of black (K), cyan (C), magenta (M), yellow (Y), special color ink (A), and special color ink (B) is provided in the ink discharge unit 14. And recording heads (ink ejection heads) 30K, 30C, 30M, 30Y, 30A, and 30B that are connected to the recording heads. Each of the ink storage units (not shown) stores an ink containing a pigment, resin particles, a water-soluble solvent, and water corresponding to each hue. , 30C, 30M, 30Y, 30A, and 30B.
Examples of the special color ink (A) and the special color ink (B) include white, orange, green, purple, light cyan, and light magenta inks.
In the ink jet recording apparatus according to the present disclosure, the ink ejection heads 30A and 30B may be omitted. Further, in addition to the ink ejection heads 30A and 30B, other special color ink ejection heads may be provided.
The positions of the ink ejection heads 30A and 30B are described after the yellow (Y) ink ejection head 30Y for convenience in FIG. 1, but are not particularly limited, and may be appropriately determined in consideration of the brightness of the special color ink. Just set it.
For example, a mode in which the head is located between the yellow ink discharging head 30Y and the magenta ink discharging head 30M and a mode in which the head is positioned between the magenta ink discharging head 30M and the cyan ink discharging head 30C can be considered.
Further, it is preferable that 30B is a head for discharging white ink.

  The ink ejection heads 30K, 30C, 30M, 30Y, 30A, and 30B respectively eject ink corresponding to an image from ejection nozzles arranged opposite to the recording surface of the recording medium. Thereby, each color ink is applied on the recording surface of the recording medium, and a color image is recorded.

  Each of the ink ejection heads 30K, 30C, 30M, 30Y, 30A, and 30B has a full-size ink ejection nozzle (nozzle) arrayed over a maximum recording width (maximum recording width) of an image recorded on a recording medium. It is a line head. It is possible to record an image on a recording medium at a higher speed than a serial type in which recording is performed while reciprocally scanning a short shuttle head in a width direction of the recording medium (a direction orthogonal to the conveying direction on the recording medium conveying surface). it can. In the present disclosure, either a serial type printing or a method capable of relatively high-speed printing, for example, a single-pass printing in which one line is formed by one scan may be adopted. According to the image recording method according to the above, a high-quality image with high reproducibility can be obtained even in the single-pass system.

  Here, the ink ejection heads 30K, 30C, 30M, 30Y, 30A, and 30B all have the same structure.

  It is preferable that the application amount of the pretreatment liquid for printing and the application amount of the ink are adjusted as necessary. For example, the amount of the pretreatment liquid for printing may be changed in accordance with the recording medium in order to adjust physical properties such as viscoelasticity of an aggregate formed by mixing the pretreatment liquid for printing and the ink. .

  The ink drying zone 15 is disposed downstream of the ink ejection unit 14 in the recording medium transport direction. The ink drying zone 15 can be configured similarly to the printing pretreatment liquid drying zone 13.

  Further, in the ink jet recording apparatus, a heating unit for performing a heat treatment on the recording medium can be arranged in a transport path from the supply unit 11 to the accumulation unit 16. For example, by arranging a heating unit at a desired position such as on the upstream side of the printing pretreatment liquid drying zone 13 or between the ink discharge unit 14 and the ink drying zone 15, the recording medium is heated to a desired temperature. By heating, drying and fixing can be performed effectively.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist of the present invention. Unless otherwise specified, “parts” and “%” are based on mass.

(Synthesis of sulfosuccinic acid monomer)
Methanol (100 g) was added to a 70% aqueous solution of sulfosuccinic acid (50.0 g, manufactured by Aldrich), and the mixture was distilled under reduced pressure at an external temperature of 80 ° C. Methanol (100 g) was added again, and distillation under reduced pressure at an external temperature of 80 ° C. was repeated twice. Methanol (150 g) was added to the obtained concentrate, and a 50% aqueous sodium hydroxide solution (51.0 g) was added dropwise little by little while stirring the system at a temperature of 20 ° C. or lower to adjust the pH to 7. Thereafter, when stirring was continued for 1 hour, precipitation was observed. This precipitate was separated by filtration and dried under reduced pressure at 80 ° C. to obtain a white solid, dimethyl sodium sulfosuccinate (SSA-Me, 36.8 g).

(Synthesis example 1)
Dimethyl sodium sulfosuccinate (20.0 g), dimethyl isophthalate (71.3 g, manufactured by Wako Pure Chemical Industries, Ltd.), diethylene glycol (51.3 g, manufactured by Wako Pure Chemical Industries, Ltd.), cyclohexane dimethanol (Wako Pure) A mixture of Yakuhin Kogyo Co., Ltd., 29.7 g) and tetraethyl orthotitanate (100 μL, Tokyo Kasei Kogyo Co., Ltd.) was heated and stirred at 180 ° C. for 3 hours under a nitrogen stream, and the produced methanol was distilled off. did. Next, the mixture was heated and stirred at 180 ° C. for 3 hours under a reduced pressure of 2 Torr (1 Torr = (101325/760) Pa) or less. Then, the obtained reaction product was taken out into a heat-resistant container processed with polytetrafluoroethylene to obtain a polyester polymer P-1.

(Synthesis examples 2 to 9)
The reaction was carried out in the same manner as in Synthesis Example 1 except that the monomers used were changed to the compositions shown in Table 1, and corresponding polyester polymers P-2 to P-9 were obtained.

In Table 1, the description of the numerical value in the column of the monomer indicates the used amount (mol%) of each monomer, and the description of "-" indicates that the corresponding monomer is not used. Indicates that
SSA-Me described in the column of monomer indicates the above-mentioned dimethyl sulfosuccinate, and other abbreviations indicate compounds represented by the following structural formula. In the following structural formula, Me represents a methyl group.
In Table 1, the description of the column of Formula I: (Formula II + Formula III) (molar ratio) indicates the content of the above structural unit I in the polymer and the content of the upper structural unit II and the structural unit III in the polymer. The molar ratio of the sum (content of the structural unit I: sum of the contents of the structural units II and III) is shown.
The description of “I”, “II” or “III” in the column of monomer indicates which structural unit corresponds to the structural unit derived from each monomer among structural units I to III. The description "-" indicates that the structural unit derived from the monomer does not correspond to any of the structural units I to III.
For example, a structural unit derived from SSA-Me with a description of “I” corresponds to the structural unit I in the specific polymer.

(Preparation of aqueous dispersion of polyester polymer)
Water was added at a ratio of 75% by mass and 5% by mass of isopropanol so that the polyester of the polymers P-1 to P-9 became 20% by mass, and the mixture was heated and stirred at 80 ° C. for 1 hour. Dispersions PE-1 to PE-9 were obtained.

(Synthesis of aqueous dispersion of self-dispersing polymer particles for ink addition)
360.0 g of methyl ethyl ketone was charged into a three-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, and the temperature was raised to 75 ° C. Thereafter, while maintaining the temperature in the flask at 75 ° C., 72.0 g of isobornyl methacrylate, 252.0 g of methyl methacrylate, 36.0 g of methacrylic acid, 72 g of methyl ethyl ketone, and “V-601” (manufactured by Wako Pure Chemical Industries, Ltd.) Of a polymerization initiator, compound name: (dimethyl 2,2'-azobis (2-methylpropionate)) (1.44 g) was added dropwise at a constant speed so that the addition was completed in 2 hours. After completion, a solution composed of 0.72 g of “V-601” and 36.0 g of methyl ethyl ketone was added thereto, and the mixture was stirred at 75 ° C. for 2 hours, and then a solution composed of 0.72 g of “V-601” and 36.0 g of isopropanol was added. In addition, the mixture was stirred for 2 hours at 75 ° C. Thereafter, the temperature was raised to 85 ° C., and the mixture was further stirred for 2 hours, and then isobornyl methacrylate / methyl methacrylate was added. A polymer solution of a acrylate / methacrylic acid (= 20/70/10 (mass ratio)) copolymer was obtained.
The weight average molecular weight (Mw) of the obtained copolymer measured in the same manner as above was 60000 (calculated in terms of polystyrene by gel permeation chromatography (GPC)), and the acid value was 64.9 mgKOH / g. Was.

  Next, 668.3 g of the obtained polymer solution was weighed, and 388.3 g of isopropanol and 145.7 ml of a 1 mol / L NaOH aqueous solution were added thereto, and the temperature in the reaction vessel was raised to 80 ° C. Next, 720.1 g of distilled water was added dropwise at a rate of 20 ml / min to disperse in water. After that, the temperature inside the reaction vessel was 80 ° C. for 2 hours, 85 ° C. for 2 hours, and 90 ° C. for 2 hours under atmospheric pressure. Kept. Thereafter, the pressure inside the reaction vessel was reduced, and a total of 913.7 g of isopropanol, methyl ethyl ketone and distilled water were distilled off, to obtain an aqueous dispersion of self-dispersing polymer particles having a solid content concentration (polymer particle concentration) of 28.0% by mass. .

(Preparation of ink composition)
The components described in the following “Magenta ink composition” were mixed to prepare a magenta ink.
Further, each component described in “Composition of cyan ink” below was mixed to prepare a cyan ink.

<Magenta ink composition>
・ Projet Magenta APD1000 (manufactured by FUJIFILM Imaging Colorants, magenta pigment dispersion, pigment concentration: 14%): 30% by mass
Aqueous dispersion of self-dispersing polymer particles: 8% by mass
・ PG (propylene glycol): 20.0% by mass
-Olfin E1010 (surfactant, manufactured by Nissin Chemical Industry Co., Ltd.): 1.0% by mass
・ Ion-exchanged water: remaining amount when the total is 100% by mass

<Cyan ink composition>
・ Projet Cyan APD1000 (manufactured by FUJIFILM Imaging Colorants, cyan pigment dispersion, pigment concentration: 12%): 20% by mass
Aqueous dispersion of self-dispersing polymer particles: 8% by mass
PG (propylene glycol; water-soluble solvent): 20.0% by mass
-Olfin E1010 (surfactant, manufactured by Nissin Chemical Industry Co., Ltd.): 1.0% by mass
・ Ion-exchanged water: remaining amount when the total is 100% by mass

(Preparation of pretreatment liquid for printing)
The components described in the following “Composition of pretreatment liquid for printing” were mixed to prepare a pretreatment liquid for printing.

<Composition of the pretreatment liquid for printing>
-Polymer aqueous dispersion: type and amount described in Table 2 or Table 3-Flocculant: type and amount described in Table 2 or Table 3-PG (propylene glycol): 10.0% by mass
・ Antifoaming agent (TSA- manufactured by Momentive Performance Materials Japan GK)
739 (15%); emulsion-type silicone antifoaming agent): 0.01% by mass as a solid content of the antifoaming agent
・ Ion-exchanged water: remaining amount of 100% by mass in total

(Evaluation)
<Evaluation of adhesion>
In each Example or Comparative Example, FE2001 (PET medium, manufactured by Futamura Chemical Co., Ltd.) was transported at 635 mm / sec, and about 1.7 g of the pretreatment liquid for printing described in Table 2 or Table 3 was printed using a wire bar coater. / M ² and immediately dried at 50 ° C. for 2 seconds. Thereafter, a blue (cyan ink + magenta ink) solid image was printed using the prepared cyan ink and the above-described magenta ink under the following image recording conditions. Immediately after printing, the image after drying on a hot plate at 80 ° C. for 30 seconds was peeled off using cellophane tape (registered trademark, No. 405, manufactured by Nichiban Co., Ltd., width 12 mm), and the degree of peeling was visually evaluated. A solid image of (cyan + magenta) color was printed. Immediately after printing, it was dried on a hot plate at 80 ° C. for 30 seconds to form an image.
A cellophane tape (registered trademark, No. 405, manufactured by Nichiban Co., Ltd., width 12 mm, hereinafter, also simply referred to as "tape") is attached to the obtained image, and the tape is peeled off from the image, thereby obtaining the adhesion of the image. Was evaluated. It can be said that the better the evaluation result of the adhesion is, the more the peeling of the image is suppressed. The evaluation results are shown in Table 2 or Table 3.
Specifically, the tape was attached by the following method.
The tape was removed at a constant speed and cut into small pieces about 75 mm long.
The tape was superimposed on the image, and an area having a width of 12 mm and a length of 25 mm at the center of the tape was stuck with a finger.
The tape was firmly rubbed with a fingertip to ensure proper contact with the coating.
Within 5 minutes of the application of the tape, the end of the tape was grasped at an angle as close to 60 ° as possible, and it was ensured that the tape was separated in 0.5 to 1.0 seconds.

[Image recording conditions]
-Head: A head in which 1,200 dpi (dot per inch, 1 inch is 2.54 cm) / 20 inch width piezo full line head for four colors was used.
-Discharged droplet volume: 2.4 pL each.
-Driving frequency: 30 kHz (substrate conveyance speed 635 mm / sec).

〔Evaluation criteria〕
A: No peeling was observed. B: Colored peeling was observed on the tape side, but no noticeable peeling was observed on the image side. C: Colored peeling was observed on the tape side, and a slight amount of ink was observed on the image side. Although significant peeling was observed, no base material was confirmed, which is within a practically acceptable range.
D: Colored peeling was observed on the tape side, the ink was almost peeled off on the image side, and the substrate was confirmed.

<Evaluation of scratch resistance of image>
An unrecorded recording medium (the same recording medium used for recording) is superimposed on a dried 100% solid image (hereinafter, also referred to as a “recorded image”) having a width of 10 mm and a length of 100 mm, and a load of 5 kg / An operation of rubbing 500 reciprocations over m ² was performed and evaluated according to the following criteria. The evaluation results are shown in Table 2 or Table 3.
The recording medium was FE2001 (PET medium, manufactured by Futamura Chemical Co., Ltd.), and the image recording conditions were the same as the image recording conditions in the above-described evaluation of adhesion.

〔Evaluation criteria〕
A: No scratch was observed on the recorded image, no ink was transferred to a recording medium on which no recording was performed, and the rub resistance of the image was extremely excellent.
B: No scratch is observed in the recorded image, but the transfer of the ink to the unrecorded recording medium is slightly recognized, but the image has excellent abrasion resistance.
C: Scratch is slightly observed in the recorded image, and transfer of the ink to the unrecorded recording medium is also slightly observed, but the abrasion resistance of the image is within a practically acceptable range.
D: The scratch on the recorded image is remarkable, and the transfer of the ink to a recording medium on which no recording is performed is also remarkable, and the abrasion resistance of the image is extremely poor.

<Evaluation of image quality>
In each Example or Comparative Example, using a FE2001 (PET medium, manufactured by Futamura Chemical Co., Ltd.), a pretreatment liquid for printing described in Table 2 was applied using a wire bar coater so as to be about 1.7 g / m ^2. At 50 ° C. for 2 seconds. Thereafter, the characters (unicode: U + 9DF9) shown in FIG. 2 are output at 2 pt, 3 pt, 4 pt, and 5 pt, respectively, under the same image recording conditions as those in the above-described evaluation of the adhesion, and the following evaluation criteria are used. evaluated. pt means a DTP point indicating a font size, and 1 pt is 1/72 inch. The evaluation results are shown in Table 2 or Table 3.
A: 2 pt characters could be reproduced B: 3 pt characters could be reproduced, but 2 pt characters could not be reproduced.
C: 4 pt characters could be reproduced, but characters of 3 pt or less could not be reproduced.
D: 4 pt characters could not be reproduced.
The reproducibility means that the characters shown in FIG. 2 are visually confirmed from a place 0.5 m away, and the horizontal line indicated by 11 in FIG. Means that it can be confirmed that the horizontal lines represented by are printed separately from each other.

<Evaluation of transfer (blocking) of components contained in the pretreatment liquid for printing>
In each Example or Comparative Example, FE2001 (resin base material, polyethylene terephthalate (PET) medium, manufactured by Futamura Chemical Co., Ltd., width 500 mm, length 2000 m) was conveyed at 500 mm / sec and used for printing shown in Table 2. The pretreatment liquid is applied by a wire bar coater so as to have a coating amount of about 1.7 g / m ² (liquid coating amount), dried on a hot plate at 80 ° C. for 30 seconds, and formed into a roll so that the surface pressure becomes 50 kPa. It was wound up and left at room temperature (25 ° C.) for one day. Thereafter, the film was unwound, and the visual visibility was evaluated by the influence of the pretreatment liquid for printing on the back surface of the base material in contact with the application surface.

〔Evaluation criteria〕
After cutting out the point of 1000 m in A4 size (29.7 cm in the length direction of the base material and 21 cm in the width direction of the base material), it was visually checked and evaluated according to the following criteria A to C. The evaluation results are shown in Table 2 or Table 3.
The cutout position in the length direction was set to be the center in the length direction of the A4 size area at the above-described position of 1000 m.
The cutting position in the width direction was such that the center in the width direction of the cut out A4-size region was the center in the width direction of the resin base material.
A: Transfer cannot be confirmed on the entire A4 size, and the visibility of the transparent portion of the substrate is not impaired.
B: Transfer was slightly confirmed on the entire surface of A4 size, and the visibility of the transparent portion of the substrate was slightly impaired, but within the practically acceptable range.
C: Transfer was clearly confirmed over the entire A4 size, and the visibility of the transparent portion of the substrate was significantly impaired.

In Tables 2 and 3, the amount of the polymer aqueous dispersion and the amount of the flocculant indicate the solid content.
In Table 2, details of the compounds described in the column of flocculant are as follows: malonic acid (organic acid): malonic acid / acetic acid (organic acid) manufactured by Tokyo Chemical Industry Co., Ltd .: acetic acid / sulfuric acid manufactured by Tokyo Chemical Industry Co., Ltd. Magnesium (polyvalent metal salt): manufactured by Nacalai Tesque, Inc. magnesium sulfate heptahydrate / polyallylamine (cationic compound): manufactured by Nitto Bo Medical, PAA-HCL-01
In Tables 2 and 3, Z446 indicates Pluscoat Z446 (manufactured by Kyogo Chemical Industry Co., Ltd.). The plus coat Z446 is a 25% by mass aqueous dispersion, and is a resin that does not contain the structural unit I described above.

From the results described in Table 2, in Examples 1 to 15 using a pretreatment liquid for printing containing a polymer containing the structural unit I represented by the formula I and water, the comparative example 1 It can be seen that the adhesiveness is excellent and the peeling of the image is suppressed.
Further, from the results of Examples 1, 2 and 4, and Example 5, it can be seen that when the polymer contains the structural unit II, an image having more excellent adhesion and abrasion resistance can be obtained.
Further, from the results of Examples 1, 2 and 3, and Example 5, it can be seen that when the polymer contains the structural unit III, an image having more excellent adhesion and abrasion resistance can be obtained.
From the results of Examples 1 and 2 and Examples 6 to 9, if the content of the structural unit I: the sum of the contents of the structural units II and III = 1: 1 to 1:40, the adhesion is obtained. Further, it can be seen that an image more excellent in suppressing transfer of components contained in the pretreatment liquid for printing can be obtained.
From the results of Example 1 and Examples 10 and 11, it can be seen that when the flocculant contains an organic acid, an image having more excellent abrasion resistance and image quality can be obtained.
From the results of Example 1 and Examples 12 to 15, the mass ratio of the solid content of the specific polymer to the solid content of the flocculant in the pretreatment liquid for printing is determined as follows: the specific polymer content: the flocculant content. = 10: 1 to 1: 2, it can be seen that an image can be obtained which is more excellent in abrasion resistance and image quality and more excellent in suppressing transfer of components contained in the pretreatment liquid for printing.
From the results of Example 1 and Example 16, it is understood that when dicarboxylic acid is contained as the organic acid, an image having more excellent image quality and abrasion resistance can be obtained.

From the results shown in Table 3, even when the printing pretreatment liquid does not contain a flocculant, the printing pretreatment liquid containing the polymer containing the structural unit I represented by the formula I and water. It can be seen that, in Examples 17 to 22 in which is used, the adhesiveness is excellent, the peeling of the image is suppressed, and an image with excellent image quality is obtained as compared with Comparative Example 2.
Further, from the results of Example 17 and Example 18, it can be seen that when the polymer contains the structural unit II and the structural unit III, an image with even better adhesion can be obtained.
From the results of Example 17 and Examples 19 to 22, if the content of the structural unit I: the sum of the contents of the structural units II and III = 1: 1 to 1:40, the adhesion is further improved. It can be seen that an excellent image can be obtained.

The disclosure of Japanese Patent Application No. 2017-129438 filed on June 30, 2017 is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards referred to in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

DESCRIPTION OF SYMBOLS 11 Supply part 12 Printing pretreatment liquid application part 13 Printing pretreatment liquid drying zone 14 Ink ejection part 15 Ink drying zone 16 Stacking part 20 Anilox roller 22 Application roller 24 Opposing rollers 30K, 30C, 30M, 30Y, 30A, 30B Ink ejection heads 41, 42, 43, 44, 45, 46 Conveying rollers

Claims (13)

A polymer containing a structural unit I represented by the following formula I,
A pretreatment liquid for printing, comprising: water.

In Formula I, Z ⁺ represents a counter cation that may be bonded to SO ₃ ⁻ or may be dissociated. The pretreatment liquid for printing according to claim 1, wherein the polymer further includes a structural unit II represented by the following formula II.
The pretreatment liquid for printing according to claim 1, wherein the polymer further includes a structural unit III represented by the following formula III.
The polymer comprises at least one of a structural unit II represented by the following formula II and a structural unit III represented by the following formula III, and in the polymer, the content of the structural unit I, the structural unit II and The molar ratio of the sum of the contents of the constituent units III to the sum of the contents of the constituent units I: the sum of the contents of the constituent units II and III = 1: 1 to 1:40. Pretreatment liquid for printing.
  The pretreatment for printing according to any one of claims 1 to 4, further comprising at least one coagulant selected from the group consisting of a salt of a polyvalent metal compound, an organic acid, and a cationic compound. liquid.   The mass ratio of the solid content of the polymer to the solid content of the flocculant in the pretreatment liquid for printing is such that the content of the polymer: the content of the flocculant = 10: 1 to 1: 2. 6. The pretreatment liquid for printing according to 5.   The printing pretreatment liquid according to claim 5, wherein the coagulant includes an organic acid.   The pretreatment liquid for printing according to any one of claims 5 to 7, wherein the organic acid includes a dicarboxylic acid. A printing substrate comprising a non-permeable medium and a solid containing a polymer containing a structural unit I represented by the following formula I.

In Formula I, Z ⁺ represents a counter cation that may be bonded to SO ₃ ⁻ or may be dissociated. A method for producing a printing substrate, comprising: a pretreatment step of applying the pretreatment liquid for printing according to claim 1 to a non-permeable medium. An ink composition containing a colorant and water, and
An ink set comprising the pretreatment liquid for printing according to any one of claims 1 to 8. A pretreatment step of applying the printing pretreatment liquid according to any one of claims 1 to 8 to a non-permeable medium,
An image recording step of discharging an ink composition containing a colorant and water onto the surface to which the printing pretreatment liquid has been applied by an inkjet method to record an image. An image recording method, comprising: ejecting an ink composition containing a colorant and water onto a surface to which the pretreatment liquid for printing according to claim 10 has been applied by an inkjet method to record an image.