JP5844238B2 - Ink composition, image forming method and printed matter - Google Patents

Description

The present invention relates to an active energy ray-curable ink composition that can be used for ink jet recording, an image forming method using the ink composition, and a print formed by the ink composition.

As an image recording method for forming an image on a recording medium such as paper based on an image data signal, there are an electrophotographic method, a sublimation type and a melt type thermal transfer method, an ink jet method and the like.
The electrophotographic system requires a process of forming an electrostatic latent image on a photosensitive drum by charging and exposure, and there is a problem that the system becomes complicated and consequently the manufacturing cost becomes high. In addition, although the thermal transfer system is inexpensive, there are problems such as high running costs and waste materials due to the use of ink ribbons.
On the other hand, the ink-jet method has an advantage that the ink can be used efficiently and the running cost is low because the ink is ejected only on the required image portion and the image is directly formed on the recording medium. In addition, it has less noise and is excellent as an image recording method.

Among the ink compositions used for image recording by the inkjet method, the active energy ray-curable aqueous ink composition is used for image printing, pretreatment for imparting printability to the recording medium, and protection of the printed image. -It can be used suitably for decoration post-processing, etc., and since it has water as the main component, it has excellent safety, such as being able to be applied to high-density inkjet recording due to its low viscosity, It is a technology with potential.
In recent years, an ink image formed on a resin recording medium by an ink composition has been increasingly used for applications such as large-area advertisements and outdoor advertisements. Particularly in the case of outdoor advertising, high water resistance is required. In addition, when a large area print or a large number of prints is formed continuously, a process for removing stains on the printing apparatus with an organic solvent is required, but the organic solvent used for cleaning is scattered and formed. If the ink adheres to the ink image, the image with low solvent resistance dissolves and removes the solvent adhering and can cause image failure such as white spots, so the image has both high water resistance and solvent resistance. There is a need for an ink composition that can form.

Examples of basic constituent materials of the active energy ray-curable water-based ink composition include water, a polymerizable substance, a polymerization initiator that generates radicals by active energy rays and starts polymerization, and a coloring material (pigment or dye). be able to. Among these, a polymerizable substance and a polymerization initiator may be prepared in an emulsion state, or may be present in a solution state given water solubility by an appropriate substituent.
Such a polymerization initiator is essential for a UV curable ink composition, but is a low molecular weight component, so that it may generate an odor when energy is applied, and it satisfies both sensitivity and stability. Ink compositions that exhibit excellent curability even in systems that do not contain a polymerization initiator have been desired.

  As an example of the active energy ray-curable ink composition containing a polymerizable substance, for example, an ink composition containing an active energy ray polymerizable substance having a specific maleimide structure is described (for example, Patent Documents 1 to 3). reference.). An ink composition containing a compound having a maleimide structure is stable and excellent in curability because a crosslinked structure is formed due to the maleimide structure during image formation.

JP 2007-119449 A JP 2000-335085 A JP 2012-51992 A

  However, from the viewpoint of forming an image excellent in solvent resistance with reduced sensitivity and with reduced sensitivity, even without containing a polymerization initiator as an essential component, with high sensitivity, There is room for improvement.

The present invention has been made in light of the above circumstances, exhibits high sensitivity and excellent curability even under low energy application conditions, suppresses the occurrence of bleeding when forming an image, and is excellent in solvent resistance. It is an object of the present invention to provide an ink composition suitable for an ink jet recording method in which an image is formed.
In addition, the present invention provides an image forming method in which the occurrence of bleeding at the time of forming an image is suppressed and an image excellent in solvent resistance is formed even under conditions of low energy application, and the bleeding is reduced and the It is an object of the present invention to provide a printed material having an image excellent in solvent property.

Specific means for solving the above problems are as follows.
<1> (a) Polymer compound containing a repeating unit having a partial structure represented by the following general formula (1) (b) Two partial structures represented by the following general formula (2) in the molecule An active energy ray-curable ink composition comprising the compound as described above and (c) an organic solvent.

In General Formula (1), R ^a and R ^b each represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and at least one of R ^a and R ^b represents an alkyl group having 1 to 4 carbon atoms. R ^a and R ^b may be bonded to each other to form a 4- to 6-membered alicyclic structure. * Indicates a binding site to the main chain or side chain in the polymer compound.

(In General Formula (2), R ¹ and R ² each independently represents an alkyl group, an alkoxy group, or an acyloxy group, or R ¹ and R ² are bonded to each other to form a ring, Represents a divalent linking group selected from an alkylene group and —O—, and R ¹ and R ² are not single bonds, and R ³ , R ⁴ , R ⁵ and R ⁶ are each independently In the compound which represents a hydrogen atom, an alkyl group, an alkoxy group, or an acyloxy group, and any one of R ³ and R ⁴ has two or more partial structures represented by (b) general formula (2) in the molecule. Represents a single bond or a divalent linking group bonded to another partial structure, and two or more of R ³ , R ⁴ , R ⁵ and R ⁶ are not bonded to each other to form a ring.

<2> The activity according to <1>, wherein the compound (b) having at least two partial structures represented by the general formula (2) in the molecule is a polymer compound containing a repeating unit having a conjugated diene structure. Energy ray curable ink composition.
<3> The active energy ray-curable ink according to <1> or <2>, wherein the repeating unit having a partial structure represented by the general formula (1) is a repeating unit represented by the following general formula (3): Composition.

In the general formula (3), ^{R a} and ^{R b} are respectively the same as ^{R a} and ^{R b} in the general formula (1). R ^c represents a hydrogen atom or a methyl group. Z represents a single bond, —COO — ** or —CONR ^d — **, R ^d represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and ** represents a bonding position with X. X represents an alkylene group having a linear, branched or cyclic structure, and the alkylene group may contain —O— in the alkylene chain and may be substituted with an alkyl group having 4 or less carbon atoms .

<4> The active energy ray-curable ink composition according to any one of <1> to <3>, further comprising (d) water.
<5> (a) The polymer compound containing a repeating unit having a hydrophilic group contained in the polymer compound is selected from the group consisting of alcoholic hydroxyl groups, alkyl-substituted carbamoyl groups, carboxyl groups, sulfo groups, and salts thereof. The active energy ray-curable ink composition according to any one of <1> to <4>, which is a polymer compound further including a repeating unit having at least one hydrophilic group.
<6> A compound in which the compound (b) having two or more partial structures represented by the general formula (2) in the molecule contains a repeating unit having a partial structure represented by the following general formula (2-1) The active energy ray-curable ink composition according to any one of <1> to <5>, which is a molecular compound. In the following general formula (2-1), * represents a binding site with a repeating unit.

<7> The active energy ray-curable ink composition according to any one of <1> to <6>, further comprising (e) a colorant.
<8> The active energy ray-curable ink composition according to any one of <1> to <7>, which is for inkjet recording.
<9> The active energy ray-curable ink composition according to any one of <1> to <8>, which is for printing on a non-permeable recording medium.

< 10 > An ink application process for applying the ink composition according to any one of <1> to <9> onto a recording medium, and a heat source at 60 ° C. or higher for the ink composition applied on the recording medium. A drying step of removing at least a part of the liquid component contained in the ink composition, and an irradiation step of irradiating the ink composition applied and dried on the recording medium with active energy rays. Including image forming method.

<11> onto a recording medium, <1> to printed matter having images formed by the active energy ray-curable ink composition according to any one of <9>.

According to the present invention, an ink jet recording that exhibits high sensitivity and excellent curability even under low energy application conditions, suppresses the occurrence of bleeding when forming an image, and forms an image with excellent solvent resistance. An active energy ray-curable ink composition suitable for the method can be provided.
In addition, according to the present invention, the occurrence of bleeding at the time of forming an image is suppressed even under conditions of low energy application, and the image forming method in which an image excellent in solvent resistance is formed, and the bleeding is reduced. Thus, it is possible to provide a print having an image excellent in solvent resistance.

Hereinafter, the active energy ray-curable ink composition of the present invention (hereinafter also simply referred to as “ink composition”), an image forming method, and a printed material will be described.
In addition, in this specification, when mentioning the amount of each component in the composition, when there are a plurality of substances corresponding to each component in the composition, the present in the composition unless otherwise specified. It means the total amount of multiple substances.
In the ink composition of the present invention, the solid content means the total mass of all components excluding the solvent among the components contained in the ink composition at 25 ° C. The solid content in the present specification includes liquid components such as low molecular weight components other than the solvent.
In the present specification, a numerical range indicated using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively.
In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended purpose of the process is achieved even if it cannot be clearly distinguished from other processes. It is.

In the present specification, when a “substituent” is described, it is used in a sense including an unsubstituted one and a substituent further unless otherwise specified. For example, an “alkyl group” is used to include both an unsubstituted alkyl group and a substituted alkyl group, and the same applies to other substituents.
“(Meth) acryl” means either or both of acrylic and methacrylic.

[Ink composition]
The ink composition of the present invention includes (a) a polymer compound containing a repeating unit having a partial structure represented by the following general formula (1), and (b) a partial structure represented by the following general formula (2) as a molecule. It is an active energy ray-curable ink composition containing a compound having two or more therein, and (c) an organic solvent.

In General Formula (1), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and at least one of R ^a and R ^b represents an alkyl group having 1 to 4 carbon atoms. Represent. R ^a and R ^b may be bonded to each other to form a 4- to 6-membered alicyclic structure. * Indicates a binding site to the main chain or side chain in the polymer compound.

(In General Formula (2), R ¹ and R ² each independently represents an alkyl group, an alkoxy group, or an acyloxy group, or R ¹ and R ² are bonded to each other to form a ring, Represents a divalent linking group selected from an alkylene group and —O—, and R ¹ and R ² are not single bonds, and R ³ , R ⁴ , R ⁵ and R ⁶ are each independently hydrogen atom, an alkyl group, an alkoxy group, or acyloxy ^group, any of R ^3, R 4, 2 or more of ^{R 5} and ^{R 6} are not able to form a ring together .R ³ and ^{R 4} One of them represents a single bond or a divalent linking group that binds to another partial structure in the compound (b).)

In the present specification, a polymer compound containing a repeating unit having a partial structure represented by the general formula (1) may be referred to as a “specific copolymer”. In addition, a compound having two or more partial structures represented by the general formula (2) in the molecule may be referred to as a “specific diene compound”.
As described later, (a) the specific copolymer is used for the purpose in addition to the repeating unit having a partial structure represented by the general formula (1) (hereinafter sometimes referred to as repeating unit (a-1)). Accordingly, the resin may further include one or more selected from a repeating unit (a-2) having a hydrophilic group and a repeating unit (a-3) having a hydrophobic group.
(A) The specific copolymer does not have the partial structure represented by the general formula (2) in the same molecule. This is because, when a polymer compound having the partial structure represented by the general formula (1) and the structure represented by the general formula (2) in the same molecule is produced, the structure represented by the general formula (1) , The partial structure represented by the general formula (2) reacts and unintentional polymerization or cross-linking occurs, so that stable production is difficult. This is because there is a problem that ink jetting properties of the used ink composition are impaired, which is not preferable.

The ink composition of the present invention contains the above-described components, thereby suppressing the occurrence of bleeding when forming an image, forming an image excellent in solvent resistance, and suitable for an ink jet recording method. used.
Here, in the present invention, the solvent resistance of the image means the durability of the formed image with respect to the organic solvent.

Although the action mechanism of the present invention is not clear, the present inventors presume as follows.
The specific copolymer in the present invention includes a repeating unit (a-1) having a partial structure represented by the general formula (1) which is a structure capable of being polymerized by irradiation with active energy rays such as ultraviolet rays. To do. These partial structures are cured by dimerization reaction with each other by applying energy. Furthermore, in the present invention, the specific diene compound having two or more partial structures capable of causing Diels-Alder reaction by heat coexists in the molecule, so that (a) the specific copolymer is added to the dimerization reaction. And (b) when the specific diene compound is dried by a heat source of 60 ° C. or higher, the Diels-Alder reaction occurs and both react with each other to form a crosslinked structure. It is presumed that the cross-linked structure is efficiently formed even under low energy application conditions, and the insolubilization (solvent resistance) of the image due to the improvement of the cross-linking density is further improved.
In addition, since the curing reaction by the formation of the crosslinked structure in the ink composition of the present invention does not contain a polymerization initiator as an essential component, both thermal crosslinking and photocrosslinking proceed to form an image. This is considered to be excellent in suppressing the occurrence of bleeding. Furthermore, as long as (a) a specific copolymer or (b) a specific diene compound can be dissolved and (c) an organic solvent is included, the present invention can be applied to both a water-based ink composition and a non-water-based ink composition. Also, for example, since the reaction proceeds as described above even in a system that does not contain a polymerization initiator, it is possible to make a system that is a low molecular weight component and does not contain a reactive polymerization initiator. In such a case, there is also an advantage that there is no fear of generation of odor caused by a polymerization initiator or a low molecular weight polymerizable compound.

The ink composition of the present invention contains (a) a specific copolymer, (b) a specific diene compound, and (c) an organic solvent, and further, as long as the effects of the present invention are not impaired, Various liquid or solid compounds may be included as additives. Examples of the additive include (d) water and (e) a colorant. By including (e) a colorant, a colored image can be obtained with the ink composition of the present invention. Further, as will be described later, other components may be included for various purposes.
Hereinafter, the ink composition of the present invention will be described in detail.

[(A) Polymer compound containing a repeating unit having a partial structure represented by the general formula (1) (specific copolymer)]
The specific copolymer contained in the ink composition of the present invention will be described in detail.
The specific copolymer is preferably a vinyl polymer, polyurethane, polyester, polyether, or polyamide, and more preferably a vinyl polymer or polyurethane.

(Repeating unit (a-1) having a partial structure represented by the general formula (1))
(A) The specific copolymer includes a repeating unit (a-1) having a partial structure represented by the following general formula (1).

In General Formula (1), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and at least one of R ^a and R ^b represents an alkyl group having 1 to 4 carbon atoms. Represent. R ^a and R ^b may be bonded to each other to form a 4- to 6-membered alicyclic structure. * Indicates a binding site to the main chain or side chain in the polymer compound.

In general formula (1), the C1-C4 alkyl group represented by R ^<a> or R ^<b > may be a linear structure or a branched structure. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group. Among these alkyl groups, an alkyl group having 1 to 2 carbon atoms (methyl group and ethyl group) is preferable, and an alkyl group having 1 carbon atom (methyl group) is particularly preferable.

In general formula (1), the alkyl group represented by R ^a or R ^b may or may not have a substituent, but preferably does not have a substituent.

R ^a and R ^b may be bonded to each other to form a 4- to 6-membered alicyclic structure.

As R ^a and R ^b , an aspect in which both are alkyl groups having 1 to 4 carbon atoms, or R ^a and R ^b are bonded to each other to form a 4- to 6-membered alicyclic structure. It is more preferable that both R ^a and R ^b are alkyl groups having 1 to 2 carbon atoms, and it is still more preferable that both R ^a and R ^b are alkyl groups having 1 carbon atom.

  Specific examples of the partial structure represented by the general formula (1) are shown below, but the present invention is not limited to these.

  The specific copolymer may have an aspect having a plurality of partial structures represented by the general formula (1) in the side chain.

  The repeating unit (a-1) having a partial structure represented by the general formula (1) is preferably a repeating unit represented by the following general formula (3).

In General Formula (3), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and at least one of R ^a and R ^b represents an alkyl group having 1 to 4 carbon atoms. Represent. R ^a and R ^b may be bonded to each other to form a 4- to 6-membered alicyclic structure. R ^c represents a hydrogen atom or a methyl group. Z represents a single bond, —COO — **, or —CONR ^d — **, R ^d represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and ** represents a bonding position with X. X represents an alkylene group having a linear, branched or cyclic structure, and the alkylene group may contain —O— in the alkylene chain and may be substituted with an alkyl group having 4 or less carbon atoms .

In General Formula (3), R ^a and R ^b each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and at least one of R ^a and R ^b represents an alkyl group having 1 to 4 carbon atoms. Represent. R ^a and R ^b may combine with each other to form a 4- to 6-membered ring structure.
^{R a} and ^{R b} in the general formula (3), the have each the same meaning as ^{R a} and ^{R b} in the general formula (1), and preferred ranges are also the same.

In the general formula (3), R ^c represents a hydrogen atom or a methyl group. R ^c is preferably a methyl group.
In General Formula (3), Z represents a single bond, —COO — **, or —CONR ^d — **, R ^d represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and ** represents X Represents the binding position. Z is preferably -COO-**.

Further, R ^d in the —CONR ^d — ** represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The alkyl group having 1 to 4 carbon atoms represented by R ^d may have a linear structure or a branched structure. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, and a t-butyl group. R ^d is preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms, that is, a methyl group or an ethyl group, and particularly preferably a hydrogen atom. If R ^d represents an alkyl group, the alkyl group may have a substituent, may not have a substituent, but preferably does not have a substituent.

  In the general formula (3), X represents a divalent organic group. Examples of the divalent organic group include an alkylene group or an aralkylene group, and an alkylene group having 2 to 20 carbon atoms or an aralkylene group having 7 to 12 carbon atoms is preferable. X is more preferably an alkylene group.

  When X represents an alkylene group, the alkylene group preferably has 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, and still more preferably 2 to 8 carbon atoms. When the carbon number of the alkylene group represented by X is within this range, the mobility of the partial structure represented by the general formula (1) present at the end of the side chain in the specific copolymer is improved. The effect is further improved.

The alkylene group represented by X may have a linear structure, a branched chain in the alkylene chain, or a cyclic structure. In addition, the alkylene group may contain a bond selected from —O—, —COO—, —OC (═O) —, and —CONH— in the alkylene chain. The alkylene group may be substituted with an alkyl group having 4 or less carbon atoms, a hydroxyl group, or a chlorine atom.
In the present invention, X, which is a divalent organic group in the general formula (3), represents an alkylene group having a linear, branched or cyclic structure, and the alkylene group contains —O— in the alkylene chain. Alternatively, it may be substituted with an alkyl group having 4 or less carbon atoms.

As the repeating unit represented by the general formula (3), R ^a and R ^b are each independently an alkyl group having 1 to 2 carbon atoms, R ^c is a methyl group, and Z is —COO — **. And X is preferably an alkylene group having 2 to 12 carbon atoms.

The content of the repeating unit (a-1) having a partial structure represented by the general formula (1) contained in the specific copolymer (preferably the repeating unit represented by the general formula (3)) is determined by the ink composition. The cured film (image) formed by the above is appropriately selected according to the intended properties. That is, the content of the repeating unit (a-1) having a partial structure represented by the general formula (1) is based on the total mass of the specific copolymer from the viewpoint of the strength and flexibility of the formed image. 20% by mass to 85% by mass, more preferably 30% by mass to 80% by mass, and further preferably 40% by mass to 70% by mass.
The content of the repeating unit having the partial structure represented by the general formula (1) may be increased as long as a stronger image is obtained, for example, within the above content range, and a more flexible image is obtained. In some cases, it is better to use less.

  The specific copolymer may contain only 1 type of repeating unit (a-1) which has a partial structure represented by General formula (1), and may contain 2 or more types.

The repeating unit (a-1) having a partial structure represented by the general formula (1) is copolymerized using a monomer having a partial structure represented by the general formula (1) as one of the copolymerization components. By doing so, it can be introduced into the specific copolymer. When the repeating unit (a-1) represented by the general formula (1) is a repeating unit represented by the general formula (3), the following general formula (3 ′) is used for the synthesis of the specific copolymer. The monomer represented can be used.
The partial structure represented by the general formula (1) can also be introduced into the copolymer by a method using a polymer reaction. Examples of such a method include a method obtained by reacting a prepolymer having a primary amino group with a corresponding anhydride, a functional group that reacts with a functional group in the prepolymer to form a bond and a general formula ( Examples thereof include a method of reacting a compound having a partial structure represented by 1) with a prepolymer.

In the general formula ^{(3 '), R a,} R b, R c, Z and X, ^R a in the formula ^{(3), R b, R} c, are respectively the Z and X synonymous, preferable ranges It is the same.

  Preferable examples of the monomer represented by the general formula (3 ′) include monomers (3′-1) to (3′-11) shown below, but the present invention is not limited thereto. .

  Monomers containing a partial structure represented by the general formula (1) represented by the monomers (3′-1) to (3′-11) are disclosed in, for example, JP-A-52-988, It can be produced with reference to the method described in JP-A-4-251258.

The specific copolymer (a) according to the present invention may contain other repeating units in addition to the repeating unit (a-1) as long as the effects of the present invention are not impaired. When the ink composition of the present invention is water-based, or when a hydrophilic organic solvent is used, it may contain a repeating unit (a-2) having a hydrophilic group.
(Repeating unit having a hydrophilic group (a-2))
The hydrophilic group contained in the repeating unit (a-2) having a hydrophilic group in the present invention is not particularly limited as long as it is a group having a function of enhancing the hydrophilicity of the specific copolymer, and is a nonionic hydrophilic group. It may be an ionic hydrophilic group (for example, an anionic hydrophilic group or a cationic hydrophilic group). Among these, it is preferable to have at least one hydrophilic group selected from alcoholic hydroxyl groups, alkyl-substituted carbamoyl groups, carboxyl groups, sulfo groups, and salts thereof.

Hereinafter, the hydrophilic group that the repeating unit (a-2) may contain will be described.
Nonionic hydrophilic groups include, but are not particularly limited to, for example, residues obtained by removing one hydrogen atom from a heterocyclic structure containing a nitrogen atom or oxygen atom, an amide group, a carbamoyl group, an alkyl-substituted carbamoyl group, an alcohol Nonionic hydrophilic groups such as a functional hydroxyl group or a group having a polyalkyleneoxy structure.

  Examples of the heterocyclic structure in the residue obtained by removing one hydrogen atom from a heterocyclic structure containing a nitrogen atom or an oxygen atom include lactones such as γ-butyrolactone; cyclic ureas such as 2-pyrrolidone and ethylene urea; ethylene carbonate , Cyclic carbonates such as propylene carbonate, cyclic ethers such as tetrahydrofuran and 1,4-dioxane; and the like.

  As the amide group, an amide group having 2 to 10 carbon atoms is preferable, and a hydrogen atom is preferably bonded to a nitrogen atom in the amide group.

  The alkyl-substituted carbamoyl group is a monoalkylcarbamoyl group in which a hydrogen atom bonded to a nitrogen atom of a carbamoyl group is substituted with an alkyl group, or two hydrogen atoms bonded to a nitrogen atom of a carbamoyl group are substituted with an alkyl group And a dialkylcarbamoyl group formed. The alkyl group may further have a substituent such as a hydroxyl group. Among these alkyl-substituted carbamoyl groups, a monoalkylcarbamoyl group substituted with an alkyl group having 1 to 8 carbon atoms or an alkyl group having 1 to 4 carbon atoms substituted with a hydroxyl group is preferable.

  Although it does not specifically limit as group which has a polyalkyleneoxy structure, The polyalkyleneoxy structure which has a C1-C4 alkyleneoxy group in a repeating unit is preferable. One type of alkyleneoxy group in the polyalkyleneoxy structure may be used, or a plurality of types of alkyleneoxy groups may be combined. The terminal group of the polyalkyleneoxy structure is preferably a hydroxyl group or an alkoxy group, more preferably a hydroxyl group or a methoxy group.

  Although it does not specifically limit as an ionic hydrophilic group, For example, ionic hydrophilic groups, such as a carboxyl group, a sulfo group, a phosphoric acid group, a phosphonic acid group, a phenolic hydroxyl group, or a quaternary ammonium group, are mentioned. The ionic hydrophilic group may form a salt.

  When the ionic hydrophilic group forms a salt, examples of the counter salt include onium salts such as alkali metal salts (Li, Na, K, etc.), ammonium salts, pyridinium salts, and phosphonium salts. Among these, alkali metal salts (Li, Na, K, etc.) or ammonium salts are preferable.

  Among these hydrophilic groups, an amide group, a carbamoyl group, an alkyl-substituted carbamoyl group, an alcoholic hydroxyl group, a group having a polyalkyleneoxy structure, a carboxyl group, a sulfo group, and a salt thereof are preferable. A carbamoyl group, a carboxyl group, a sulfo group, and salts thereof are more preferable. Particularly preferred are carboxyl groups and salts thereof.

  The repeating unit (a-2) having a hydrophilic group is preferably a repeating unit represented by the following general formula (4).

In general formula (4), R ^cy represents a hydrogen atom or a methyl group. Z ^y represents —COO — ***, —CONR ^dy — ***, or a single bond, and R ^dy represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. R ^y represents a group selected from the group consisting of a single bond, an alkylene group, an arylene group, and an aralkylene group. A represents a hydrophilic group. *** represents a position where Z ^y is bonded to R ^y .

The general formula (4) will be described in detail.
In general formula (4), R ^cy represents a hydrogen atom or a methyl group.

In the general formula (4), Z ^y represents —COO — ***, —CONR ^dy — ***, or a single bond, and is preferably —COO — ***. Incidentally, *** is a position ^{where Z y} is bonded to ^{R y.}

R ^dy represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. The alkyl group having 1 to 4 carbon atoms may have a linear structure or a branched structure. Specifically, it represents a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, or a t-butyl group. R ^dy is preferably a hydrogen atom or an alkyl group having 1 to 2 carbon atoms (that is, a methyl group or an ethyl group), and particularly preferably a hydrogen atom.

R ^dy may or may not have a substituent, but preferably does not have a substituent. Examples of the substituent that R ^dy may have include an aryl group having 6 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a hydroxyl group, a carboxyl group, and a halogen atom (F, Cl, Br, I, etc.). Etc.

In General Formula (4), R ^y represents a single bond or a group selected from the group consisting of an alkylene group, an arylene group, and an aralkylene group, an alkylene group having 1 to 20 carbon atoms, and an arylene having 6 to 20 carbon atoms. It is preferably a group or an aralkylene group having 7 to 20 carbon atoms.
When ^Ry is a group selected from the group consisting of an alkylene group, an arylene group, and an aralkylene group, these groups may or may not have a substituent. The alkylene group, arylene group, and aralkylene group represented by R ^y may have an ether bond, an ester bond, an amide bond, or a urethane bond in the structure.
In the general formula (4), R ^y is preferably a single bond.

When ^Ry is a group selected from the group consisting of an alkylene group, an arylene group, and an aralkylene group, these groups may further have a substituent. Examples of the substituent include an aryl group having 6 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a hydroxyl group, a carboxyl group, a halogen atom (F, Cl, Br, I, etc.) and the like.

When ^Ry is an alkylene group having 1 to 20 carbon atoms, the alkylene group may have a linear structure, a branched structure, or a cyclic structure. When ^Ry is an alkylene group, the number of carbon atoms is more preferably 2 to 12, and further preferably 2 to 8. Specific examples of the alkylene group for R ^y include —CH ₂ —, —C ₂ H ₄ —, —C (CH ₃ ) ₂ —CH ₂ —, —CH ₂ C (CH ₃ ) ₂ CH ₂ —, —C. _{6 H 12 -, - C 4} H 7 (C 4 H 9) C 4 H 8 -, C 18 H 36 -, 1,4-trans- cyclohexylene _{group, -C 2 H 4 -OCO-C} 2 H 4 _{-, - C 2 H 4 -OCO} -, - C 2 H 4 -O-C 5 H 10 -, - CH 2 -O-C 5 H 9 (C 5 H 11) -, - C 2 H 4 -CONH _{-C 2 H 4 -, - C} 4 H 8 -OCONH-C 6 H 12 -, - CH 2 -OCONHC 10 H 20 -, - CH 2 CH (OH) CH 2 -, and the like.

When ^Ry is an arylene group having 6 to 20 carbon atoms, the arylene group preferably has 6 to 18 carbon atoms, more preferably 6 to 14 carbon atoms, and particularly preferably 6 to 10 carbon atoms. . Specific examples of the arylene group represented by R ^y include a phenylene group, a biphenylene group, —C ₆ H ₄ —CO—C ₆ H ₄ —, a naphthylene group, and the like.

When ^Ry is an aralkylene group having 7 to 20 carbon atoms, the aralkylene group preferably has 7 to 18 carbon atoms, more preferably 7 to 14 carbon atoms, and particularly preferably 7 to 10 carbon atoms. . Specific examples of the aralkylene group represented by R ^y _{is, -C 3 H 6 -C 6 H} 4 -, - C 2 H 4 -C 6 H 4 -C 6 H 4 -, - CH 2 -C 6 H _{4 -C 6 H 4 -C 2 H} 4 -, - C 2 H 4 -OCO-C 6 H 4 - , and the like.

  Examples of the hydrophilic group represented by A in the general formula (4) include the hydrophilic groups described above, and the preferred range is also the same.

When the specific copolymer has a repeating unit represented by the general formula (4), the content of the repeating unit represented by the general formula (4) in the specific copolymer is as follows.
When the hydrophilic group A in General formula (4) is an ionic hydrophilic group, content of the repeating unit represented by General formula (4) is 5 mass%-50 mass% in a specific copolymer. It is preferably 5% by mass to 40% by mass, more preferably 1% by mass to 20% by mass.
When the hydrophilic group A in the general formula (4) is a nonionic hydrophilic group, the specific copolymer preferably has 20% by mass to 95% by mass, more preferably 30% by mass to 80% by mass, 30 mass%-70 mass% is especially preferable.

  The repeating unit represented by the general formula (4) is derived from a monomer represented by the following general formula (4 ′), and the specific copolymer is obtained by including these monomers as a copolymerization component. The repeating unit (a-2) is introduced therein.

In the general formula ^{(4 '), R cy,} Z y, R y, and A, ^R cy in the general formula ^{(4), Z y, R} y, and A and have the same meanings, the preferred range is also the same is there.

  Preferable examples of the monomer represented by the general formula (4 ′) include the following monomer compounds, but the present invention is not limited thereto.

  Methoxypolyethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, poly (ethylene glycol-co-propylene glycol) (meth) acrylate, 2-hydroxyethyl (meth) acrylate, glycerol (meth) Acrylate (meth) acryloyloxyethyl ethylene urea, vinylpyrrolidone, 3- (meth) acryloyloxy-γ-butyrolactone, acrylamide, tert-butylacrylamide, N, N-dimethyl (meth) acrylamide, diacetone acrylamide, (meth) Sodium acrylate, potassium (meth) acrylate, tetrabutylammonium (meth) acrylate, mono (meth) acryloyloxyethyl succinic acid, Sodium (meth) acryloyloxyethyl succinate, sodium mono (meth) acryloyloxyethyl phthalate, (meth) acryloyloxyethyl acid phosphate, sodium 2-acrylamido-2-methylpropanesulfonate, 2-acrylamide- Examples include 2-methylpropane sulfonic acid, styrene sulfonic acid, sodium styrene sulfonate, and vinyl benzoic acid.

  As the monomer represented by the general formula (4 ′), a commercially available compound can be used, and the monomer can be produced by a generally known method.

  In the present invention, in addition to the monomer represented by the general formula (4 ′), unsaturated dicarboxylic acids such as maleic acid, maleic anhydride, and fumaric acid, and anhydrides thereof, and further derived therefrom. Dicarboxylic acid salts can also be preferably used.

The content of the repeating unit (a-2) having a hydrophilic group in the specific copolymer varies depending on the type of the hydrophilic group, but the specific copolymer may be water-soluble. preferable.
Here, that the specific copolymer exhibits water solubility means that the specific copolymer can be dissolved in 3% by mass or more in water at 25 ° C.

When the specific copolymer includes a repeating unit (a-2) having a hydrophilic group, the content of the repeating unit (a-2) is preferably 8% by mass to 25% by mass, and 10% by mass. More preferably, it is -23 mass%, It is further more preferable that it is 10 mass%-20 mass%. When the ink composition of the present invention is a non-aqueous ink composition, (a) the specific copolymer does not necessarily include the repeating unit (a-2).
When the content of the repeating unit (a-2) having a hydrophilic group is in the above range, the polarity of the specific copolymer is more appropriately maintained, and the formed image is more suitable in the aqueous ink composition. Expresses water resistance.
The specific copolymer may contain only one type of repeating unit (a-2) having a hydrophilic group, or may contain two or more types.

(Repeating unit having a hydrophobic group (a-3))
The specific copolymer may contain a repeating unit (a-3) having a hydrophobic group. When the ink composition of the present invention is a non-aqueous ink composition, it preferably contains a repeating unit (a-3). Even when the aqueous ink composition is used, the repeating unit (a-3) is useful for improving the water resistance of the formed image.
By including a repeating unit having a hydrophobic functional group, the polarity of the specific copolymer is more appropriately maintained, and the ink image formed by the ink composition is further excellent in water resistance and non-absorbing recording. It also has excellent adhesion to the medium.

The repeating unit (a-3) having a hydrophobic group has a solubility (25 ° C.) in water of a homopolymer having only a repeating unit (a-3) having a weight average molecular weight of 10,000 or more. It is preferably a repeating unit derived from a vinyl monomer that is less than 0.0% by mass. Any repeating unit derived from the vinyl monomer can be used without limitation, and among them, a repeating unit derived from a monomer selected from alkyl esters of (meth) acrylic acid and aralkyl esters is preferred.
Among these, from the viewpoint of adjusting the polarity of the specific copolymer within an appropriate range, the hydrophobic group is preferably a monomer having 5 to 22 carbon atoms having an alkyl group, and having 8 carbon atoms having an alkyl group. A monomer having ˜22 is more preferred, and a monomer having a total carbon number of 8-14 having an alkyl group is more preferred. That is, in the case of alkyl acrylate, it is an ester having an alkyl group having 4 to 19 carbon atoms, and an ester having an alkyl group having 4 to 13 carbon atoms is preferred. In the case of alkyl methacrylate, it is an ester having an alkyl group having 4 to 18 carbon atoms, and an ester having an alkyl group having 4 to 10 carbon atoms is preferred.
The alkyl group may be linear or branched, and may be cyclic. Further, it may be an aralkyl ester such as a benzyl group or a phenoxyethyl group.

  Although the repeating unit (a-3) which has a hydrophobic group which a specific copolymer can contain is illustrated below, the repeating unit (a-3) which has a hydrophobic group in this invention is not limited to these. Specific examples of the repeating unit (a-3) having a hydrophobic group include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl ( (Meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) Acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, isobornyl methacrylate, tetrahydrofurfuryl (meth) acrylate, aceto (Meth) acrylic acid esters such as cetoxyethyl (meth) acrylate, styrenes such as styrene, α-methylstyrene, 4-methylstyrene, vinyl ethers such as chloroethyl vinyl ether, etc. 5 to 22 (meth) acrylic acid alkyl esters, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate , N-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate , Benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, etc. are preferable, n-propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate , Tert-butyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, and the like are more preferable. Moreover, n-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, phenoxyethyl (meth) acrylate Is particularly preferred.

The specific copolymer may contain only 1 type of repeating unit (a-3) which has a hydrophobic group, and may contain 2 or more types.
From the viewpoint of reducing the polarity of the copolymer, the repeating unit (a-3) having a hydrophobic group is preferably in the range of 5% by mass to 72% by mass, and 20% by mass to 65% by mass in the specific copolymer. Is more preferable, and 25% by mass to 60% by mass is most preferable.

  The weight average molecular weight of the specific copolymer contained in the ink composition of the present invention is preferably in the range of 5,000 to 150,000 from the viewpoint of water resistance, and the ejection stability when applied to the inkjet method is improved. From the viewpoint of enhancing, a range of 5,000 to 100,000 is more preferable.

  In addition, the weight average molecular weight of a specific copolymer is measured by a gel permeation chromatograph (GPC). GPC uses HLC-8020GPC (manufactured by Tosoh Corporation), TSKgel SuperHZM-H, TSKgel SuperHZ4000, TSKgel SuperHZ200 (4.6 mm ID × 15 cm, Tosoh Corporation) as columns and THF (tetrahydrofuran) as an eluent. , And the column oven set temperature is 40 ° C. Standard polystyrene was used for calculation of molecular weight.

  Specific examples of the specific copolymer [Exemplary Compounds A-1 to A-6] are shown together with the weight average molecular weight and the SP value, but the specific copolymer in the present invention is limited to these. is not. In the following exemplary compounds, the copolymerization ratios indicated using a, b, c, d and e are based on mass.

  The specific copolymer includes, for example, a monomer for forming the repeating unit (a-1) having a partial structure represented by the general formula (1), and a repeating unit (optionally having a hydrophilic group) A monomer for forming a-2) and a monomer for forming a repeating unit (a-3) having a hydrophobic group optionally used are polymerized by a known polymerization method and necessary Accordingly, the acid group can be obtained by neutralizing with an alkali metal hydroxide or the like. Specifically, for example, a method according to the polymerization method described in JP-A-52-988, JP-A-55-154970, Langmuir Vol. 18, No. 14, pages 5414-5421 (2002), etc. A specific copolymer can be produced.

The ink composition of the present invention may contain only one type of specific copolymer, or may contain two or more types in combination.
As content of the specific copolymer in the ink composition of this invention, it is preferable that it is 2 mass%-20 mass% with respect to the total mass of an ink composition, and it is from a viewpoint of suppressing bleeding and sclerosis | hardenability. 5 mass%-20 mass% are more preferable, and 5 mass%-15 mass% are still more preferable.

[(B) Compound having 2 or more partial structures represented by the following general formula (2) in the molecule (specific diene compound)]
The specific diene compound contained in the ink composition of the present invention will be described in detail.

In the general formula (2), R ¹ and R ² each independently represent an alkyl group, an alkoxy group, or an acyloxy group, or R ¹ and R ² are bonded to each other to form a ring, alkylene Represents a divalent linking group selected from a group and —O—, and neither R ¹ nor R ² is a single bond. R ³ , R ⁴ , R ⁵ and R ⁶ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, or an acyloxy group, and any one of R ³ and R ⁴ is represented by (b) the general formula (2) Represents a single bond or a divalent linking group that binds to another partial structure in a compound having two or more partial structures represented by Two or more of R ³ , R ⁴ , R ⁵ and R ⁶ are not bonded to each other to form a ring. When two or more of these are bonded to form a ring structure, the reactivity of the curing reaction is lowered, and it is difficult to obtain the excellent effect of the present invention.

In the present invention, (a) the partial structure represented by the general formula (1) of the specific copolymer is a diene isomer in the Diels-Alder reaction, and (b) the general formula (2) of the specific diene compound. The partial structure represented by is a conjugated diene. The partial structure represented by the general formula (2) is not particularly limited as long as it is a known structure that reacts with a maleimide structure included in the partial structure represented by the general formula (1) and a Diels-Alder reaction. The following structure is used.
As the conjugated diene represented by the general formula (2) used in the present invention, any known conjugated diene generally used in Diels-Alder reaction can be arbitrarily used.
In the general formula (2), the substituents represented by R ¹ and R ² are each independently a hydrogen atom, an alkyl group, an alkoxy group, or an acyloxy group, or R ¹ and R ² are bonded to each other. And a single bond or a divalent linking group forming a ring, at least one of which is an alkylene group or —O—.

Among these, as R ¹ and R ² , a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms is preferable, and a hydrogen atom, an alkyl group having 1 to 2 carbon atoms, or A C1-C2 alkoxy group is preferable.
In addition, when R ¹ and R ² are a divalent linking group forming a ring, each independently represents a single bond, an alkylene group or —O—. Among these, R ¹ is an alkylene group having 1 to 2 carbon atoms or —O—, and R ² is a single bond, that is, R ¹ and R ² are bonded to each other to form a cyclopentadiene. An embodiment in which a ring, a cyclohexadiene ring or a furan ring is formed is preferred, and R ¹ is —O— and R ² is a single bond, that is, R ¹ and R ² are bonded to each other to form a furan ring. The aspect which forms is more preferable.
R ^{3 to} R ⁶ are an alkyl group, an alkoxy group, or an acyloxy group, and among them, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or an acyloxy group having 1 to 4 carbon atoms is preferable. And an alkyl group having 1 to 4 carbon atoms and an alkoxy group having 1 to 4 carbon atoms are more preferable. R ^{3 to} R ⁶ do not form a ring by bonding the rings together. When R ^{3 to} R ⁶ each represent an alkyl group, an alkoxy group, or an acyloxy group, these may further have a substituent, and examples of the substituent that can be introduced include a hydroxyl group and a halogen atom. It is done.
Here, either one of R ³ and R ⁴ represents a divalent linking group or a single bond that binds to (b) another partial structure in the specific diene compound.
In the present invention, when (b) the specific diene compound is a low molecular compound, (b) the specific diene compound is a compound represented by the following general formula (2-2) or general formula (2-3). Is preferred.

In the general formula (2-2), ^{Q 1} represents a ^{p 1} divalent linking group, ^{p 1} represents an integer of 2 or more. p ¹ is preferably 2 to 6, more preferably 2 to 4, and still more preferably 2 or 3.
In the general formula (2-3), ^{Q 2} represents a ^{p 2} divalent linking group, ^{p 2} is an integer of 2 or more. p ² is preferably 2 to 6, more preferably 2 to 4, and still more preferably 2 or 3.
Here, in the compound represented by the general formula (2-2) or the general formula (2-3), the conjugated diene structure represented by the general formula (2) is bonded to the linking group Q ¹ or Q ^2. A compound having a plurality of diene structures in the molecule.
The linking groups Q ¹ and Q ² are not particularly limited as long as they are independently a group that can be linked to the structure represented by the general formula (2). Examples of Q ¹ and Q ² include structures in which p ¹ or p ² hydrogens are removed from a branched or straight chain alkyl group having 1 to 12 carbon atoms, respectively, to form Q ¹ and Q ² . The alkyl group may contain an ether group, an ester group, an amino group, an amide bond, a silyl ether group, a thiol group, or the like in the structure.

  Examples of the compound represented by the general formula (2-2) and the structure represented by the general formula (2-3) include compounds having the following structures, but the present invention is not limited thereto. Absent.

An embodiment in which the (b) specific diene compound used in the ink composition of the present invention is a polymer compound is also preferable. (B) Since the specific diene compound is a polymer compound, a large number of diene structures represented by the general formula (2) can be introduced into the compound, so that the curability is further improved.
When the polymer compound has a partial structure represented by the general formula (2), the introduction site is arbitrary, and may be included as a constituent element of the main chain, which is a so-called pendant structure included in the side chain of the polymer. May be included at the terminal of the polymer compound, but the mobility of the partial structure becomes better, the number of introductions can be easily limited, and the number of structures included in one molecule. From the viewpoint of being easy to increase, it is preferable to introduce the polymer compound as a repeating unit.
When the structure represented by the general formula (2) is contained as a repeating unit of the polymer compound, the polymer compound is obtained by homopolymerizing or copolymerizing the monomer having the structure represented by the general formula (2). And a compound having a partial structure capable of forming a covalent bond with the functional group and a structure represented by the general formula (2) using a method having a specific functional group in the repeating unit of the polymer compound And a method of introducing the structure represented by the general formula (2) into the polymer compound.
In the present invention, when a polymer compound is used as the specific diene compound (b), the structure represented by the general formula (2) is represented by the general formula (2-1) from the viewpoint of stability during synthesis. A structure is preferred. In the case of the structure represented by the general formula (2-1), for example, when a vinyl polymer, polyurethane, polyester, or polyamide is synthesized, a monomer having a structure represented by the general formula (2-1) is polymerized. Even in this case, the partial structure can be easily introduced into the polymer compound without causing a side reaction. In the general formula (2-1), * represents a binding site with a repeating unit. The structure represented by the general formula (2-1) may be directly bonded to the main chain of the repeating unit at the position indicated by *, or may be bonded to the main chain via an appropriate linking group. It may be bonded to the side chain at the position indicated by *. From the viewpoint of good mobility of the structure represented by the general formula (2-1), the structure is preferably connected at a position away from the main chain by about 2 to 8 atoms. It is preferable that it is bonded to the main chain via an appropriate linking group and bonded to the side chain.
Examples of the polymer compound having a partial structure represented by the general formula (2-1) used in the present invention include the following compounds, but the present invention is not limited thereto.

The ink composition of the present invention may contain only one (b) specific diene compound, or may contain two or more kinds in combination.
The content of (b) the specific diene compound in the ink composition of the present invention includes (a) the partial structure represented by the general formula (1) of the specific copolymer and (b) the general content of the specific diene compound. The partial structure represented by the formula (2) is preferably in an amount in a molar ratio of 9: 1 to 2: 1, and in an amount of 8: 1 to 3: 1. More preferably, the amount is in the range of 8: 1 to 4: 1. (B) When the content of the diene compound is in the above range, the balance between thermal curing and photocuring in the ink composition becomes better, and curability and suppression of image bleeding are further improved.
As described above, it is important from the viewpoint of reactivity that the (a) specific copolymer and the (b) specific diene compound coexist in the ink composition. For example, the general formula (1) In the copolymer including the repeating unit having the partial structure represented by the formula (2) and the repeating unit having the partial structure represented by the general formula (2), the reaction site is fixed, so that the excellent effect of the present invention is difficult to obtain. .

(B) The specific diene compound is a method of polymerizing a vinyl monomer having a specific diene structure such as (2-1) such as furfuryl methacrylate by a known method such as radical polymerization or ionic polymerization, or a specific diene structure. A method of synthesizing polyurethanes, polyureas, polyesters, and polyamides having specific diene structure by polymerizing with diol or diamine and diisocyanate or dicarboxylic acid, a method of introducing a specific diene structure by post-reaction to a polymer compound having a functional group, etc. In addition to a known method, it can also be obtained as a commercial product. For example, as a low molecular weight compound, 2,2-di (2-furyl) propane manufactured by Tokyo Chemical Industry Co., Ltd. Examples thereof include difurfuryl disulfide manufactured by Kogyo Co., Ltd. and Tokyo Chemical Industry Co., Ltd.
The presence of the (b) specific diene compound in the ink composition can be confirmed by an analysis means such as NMR.

[(C) Organic solvent]
The ink composition of the present invention contains an organic solvent.
<Water-soluble organic solvent>
When the ink composition of the present invention is a water-based ink composition, it is preferable to contain a water-soluble organic solvent as the organic solvent. The water-based ink composition preferably further contains (d) water described later as a main solvent in addition to (c) the organic solvent.
Here, the water-soluble organic solvent means an organic solvent having a solubility in water at 25 ° C. of 10% by mass or more.

Examples of water-soluble organic solvents that can be used in the present invention include the following.
Alcohols (eg, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol, hexanol, cyclohexanol, benzyl alcohol, etc.),
Polyhydric alcohols (for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin, hexanetriol, thiodiglycol, 2- Methylpropanediol, etc.)
Polyhydric alcohol ethers (for example, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, tripropylene Glycol monomethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monobutyl ether, ethylene glycol Monophenyl ether, propylene glycol monophenyl ether, etc.),

-Amines (eg, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentane Methyldiethylenetriamine, tetramethylpropylenediamine, etc.),
Amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide, etc.), methoxypropionamide, N-methylmethoxypropionamide, N, N-dimethylmethoxypropionamide, n-butoxypropionamide, N-methyl n-butoxypropionamide, N, N-dimethyl n-butoxypropionamide, etc.), heterocycles (for example, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexylpyrrolidone, 2-oxazolidone, 1, 3-dimethyl-2-imidazolidinone, γ-butyrolactone, propylene carbonate, ethylene carbonate, ethylene urea, etc.),
・ Sulphoxides (for example, dimethyl sulfoxide),
-Sulfones (for example, sulfolane),
・ Others (urea, acetonitrile, acetone, etc.)

  Preferable water-soluble organic solvents include polyhydric alcohol ethers and heterocyclic rings, and these may be used in combination.

Among the polyhydric alcohol ethers, so-called glycol ethers are preferable, specifically, tripropylene glycol monomethyl ether, dipropylene glycol monomethyl ether, and dipropylene glycol dimethyl ether are preferable, and 2-dipropylene glycol monomethyl ether is more preferable.
As the heterocyclic ring, 2-pyrrolidone, γ-butyrolactone, propylene carbonate, ethylene urea and the like are preferable, and 2-pyrrolidone and γ-butyrolactone are particularly preferable.
In particular, a solvent having a high boiling point can be preferably used, and the boiling point at normal pressure is preferably 120 ° C. or higher, more preferably 150 ° C. or higher.

  One or more water-soluble organic solvents may be used in combination. When the water-soluble organic solvent is added, the addition amount in the ink composition is preferably 1% by mass to 60% by mass, and more preferably 2% by mass to 35% by mass.

[Other ingredients]
In addition to the essential components (a) specific copolymer, (b) specific diene compound, and (c) organic solvent, the ink composition of the present invention contains water, Colorants and known additives can be used in combination. Hereinafter, other components that can be used in the ink composition of the present invention will be described.

[(D) Water]
The ink composition of the present invention may contain water. When the ink composition of the present invention is a water-based ink composition, water is contained as a main solvent.
(D) As water, it is preferable to use ion-exchange water, distilled water, etc. which do not contain an impurity.
When the ink composition of the present invention contains water, it is contained as a main solvent of the water-based ink composition, and therefore the content is preferably 10% by mass to 97% by mass, and 30% by mass to 95% by mass. %, More preferably 50% by mass to 85% by mass.
In addition, the non-aqueous ink composition may contain water for the purpose of improving the solubility of the combination component, and the preferable content in that case is appropriately selected depending on the combination component. It is 5 mass% or less, ie, it is the range of 0 mass%-5 mass%.

[(E) Colorant]
The ink composition of the present invention may contain (e) one or more colorants, and a color ink composition is obtained by containing a colorant.
Examples of the colorant include dyes and pigments, and pigments are preferable from the viewpoint of durability such as heat resistance, light resistance, and water resistance.

  When a pigment is used as the colorant, the pigment can be contained in the ink composition as a pigment dispersion. Use of a pigment dispersion as a colorant is preferable from the viewpoint of improving solvent resistance. As the pigment dispersion, a self-dispersed pigment can be used in addition to a pigment dispersed with a pigment dispersant.

(Pigment)
As the pigment used as the colorant, generally used organic pigments, inorganic pigments, and those obtained by dyeing resin particles with a dye can be used. Usually, any commercially available pigment can be used, and further, a pigment pretreated with a commercially available pigment dispersion or surface treatment agent, for example, a pigment dispersed in an insoluble resin or the like as a dispersion medium, Or what grafted resin to the pigment surface etc. can be used unless the effect of this invention is impaired.
Examples of these pigments include, for example, “Pigment Dictionary” (2000), edited by Seijiro Ito. Herbst, K.M. Hunger “Industrial Organic Pigments”, JP 2002-12607 A, JP 2002-188025 A, JP 2003-26978 A, and JP 2003-342503 A3.

  Examples of organic pigments and inorganic pigments that can be used in the present invention include C.I. I. Pigment Yellow 1 (Fast Yellow G, etc.), C.I. I. A monoazo pigment such as C.I. Pigment Yellow 74; I. Pigment Yellow 12 (disaji yellow, etc.), C.I. I. Pigment yellow 17, C.I. I. Pigment yellow 97, C.I. I. Pigment yellow 3, C.I. I. Pigment yellow 16, C.I. I. Pigment yellow 83, C.I. I. Pigment yellow 155, C.I. I. Disazo pigments such as C.I. Pigment Yellow 219; I. Azo lake pigments such as C.I. Pigment Yellow 100 (eg Tartrazine Yellow Lake); I. Pigment yellow 95 (condensed azo yellow, etc.), C.I. I. Pigment yellow 93, C.I. I. Pigment yellow 94, C.I. I. Pigment yellow 128, C.I. I. Condensed azo pigments such as C.I. Pigment Yellow 166; I. Acidic dye lake pigments such as C.I. Pigment Yellow 115 (such as quinoline yellow lake); I. Basic dye lake pigments such as C.I. Pigment Yellow 18 (Thioflavin Lake, etc.); I. Anthraquinone pigments such as CI Pigment Yellow 24 (Flavantrone Yellow), isoindolinone pigments such as Isoindolinone Yellow 3RLT (Y-110), C.I. I. Quinophthalone pigments such as C.I. Pigment Yellow 138 (Kinophthalone Yellow); I. An isoindoline pigment such as C.I. Pigment Yellow 139 (isoindoline yellow); I. Nitroso pigments such as C.I. Pigment Yellow 153 (nickel nitroso yellow, etc.); I. Metal complex salt azomethine pigments such as C.I. Pigment Yellow 117 (copper azomethine yellow, etc.); I. Pigment yellow 120 (benzimidazolone yellow) C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 175, C.I. I. Pigment yellow 180, C.I. I. Pigment yellow 181, C.I. I. An acetolone pigment such as C.I. Pigment Yellow 194; I. And nickel azo pigments such as CI Pigment Yellow 150. Among these, C.I. I. Pigment yellow 74, C.I. I. Pigment yellow 120, C.I. I. Pigment yellow 150, C.I. I. Pigment yellow 151, C.I. I. Pigment yellow 154, C.I. I. Pigment yellow 155, C.I. I. Pigment Yellow 180 or the like is preferably used.

  Examples of those exhibiting red or magenta color include C.I. I. Monoazo pigments such as CI Pigment Red 3 (Toluidine Red, etc.); I. Pigment red 1, C.I. I. Pigment red 4, C.I. I. B-naphthol pigments such as C.I. Pigment Red 6; I. Disazo pigments such as C.I. Pigment Red 38 (Pyrazolone Red B, etc.); I. Pigment Red 53: 1 (Lake Red C, etc.) and C.I. I. Pigment Red 57: 1 (Brilliant Carmine 6B etc.), C.I. I. Pigment red 52: 1, C.I. I. Azo lake pigments such as C.I. Pigment Red 48 (B-oxynaphthoic acid lake, etc.); I. Pigment red 144 (condensed azo red, etc.), C.I. I. Pigment red 166, C.I. I. Pigment red 220, C.I. I. Pigment red 214, C.I. I. Pigment red 221, C.I. I. Condensed azo pigments such as C.I. Pigment Red 242, C.I. I. Pigment Red 174 (Phloxine B lake, etc.), C.I. I. Acidic dye lake pigments such as C.I. Pigment Red 172 (Erythrosin Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Red 81 (Rhodamine 6G 'lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Red 177 (eg, dianthraquinonyl red); I. Thioindigo pigments such as C.I. Pigment Red 88 (Thioindigo Bordeaux, etc.); I. Perinone pigments such as CI Pigment Red 194 (perinone red, etc.)

C. I. Pigment red 149 (perylene scarlet, etc.), C.I. I. Pigment red 179, C.I. I. Pigment red 178, C.I. I. Pigment red 190, C.I. I. Pigment red 224, C.I. I. Pigment red 123, C.I. I. Perylene pigments such as C.I. Pigment Red 224; I. Pigment violet 19 (unsubstituted quinacridone), C.I. I. Pigment red 122 (quinacridone magenta, etc.), C.I. I. Pigment red 262, C.I. I. Pigment red 207, C.I. I. Quinacridone pigments such as CI Pigment Red 209, and quinacridone pigments which are solid solutions of the plurality of quinacridone pigments; I. Isoindolinone pigments such as CI Pigment Red 180 (isoindolinone red 2BLT, etc.); I. Alizarin lake pigments such as C.I. Pigment Red 83 (Madalake, etc.); I. Pigment red 171, C.I. I. Pigment red 175, C.I. I. Pigment red 176, C.I. I. Pigment red 185, C.I. I. Naphtholone pigments such as C.I. Pigment Red 208; I. Naphthol AS lake pigments such as C.I. Pigment Red 247; I. Pigment red 2, C.I. I. Pigment red 5, C.I. I. Pigment red 21, C.I. I. Pigment red 170, C.I. I. Pigment red 187, C.I. I. Pigment red 256, C.I. I. Pigment red 268, C.I. I. Naphthol AS pigments such as C.I. Pigment Red 269; I. Pigment red 254, C.I. I. Pigment red 255, C.I. I. Pigment red 264, C.I. I. And diketopyrrolopyrrole pigments such as CI Pigment Red 27. Among these, C.I. I. Pigment violet 19 (unsubstituted quinacridone), C.I. I. Pigment red 122 (quinacridone magenta, etc.), C.I. I. Pigment red 262, C.I. I. Pigment red 207, C.I. I. A quinacridone pigment such as CI Pigment Red 209 and a quinacridone pigment which is a solid solution containing a plurality of these quinacridone pigments are preferred.

  Examples of pigments exhibiting blue or cyan colors include C.I. I. Disazo pigments such as C.I. Pigment Blue 25 (Dianisidine Blue, etc.); I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Pigment blue 15: 6, C.I. I. Phthalocyanine pigments such as C.I. Pigment Blue 16 (phthalocyanine blue, etc.); I. Acidic dye lake pigments such as C.I. Pigment Blue 24 (Peacock Blue Lake, etc.); I. Basic dye lake pigments such as C.I. Pigment Blue 1 (Viclotia Pure Blue BO Lake, etc.); I. Anthraquinone pigments such as C.I. Pigment Blue 60 (Indantron Blue, etc.); I. And alkali blue pigments such as CI Pigment Blue 18 (Alkali Blue V-5: 1). Among these, C.I. I. Pigment blue 15, C.I. I. Pigment blue 15: 1, C.I. I. Pigment blue 15: 2, C.I. I. Pigment blue 15: 3, C.I. I. Pigment blue 15: 4, C.I. I. Copper phthalocyanine pigments such as CI Pigment Blue 15: 6 are preferred.

Examples of the pigment exhibiting green include C.I. I. Pigment green 7 (phthalocyanine green), C.I. I. Phthalocyanine pigments such as C.I. Pigment Green 36 (phthalocyanine green); I. Pigment green 8 (nitroso green), C.I. I. And azo metal complex pigments such as CI Pigment Green 10.
Examples of orange pigments include C.I. I. An isoindoline pigment such as C.I. Pigment Orange 66 (isoindoline orange); I. Anthraquinone pigments such as C.I. Pigment Orange 51 (dichloropyrantron orange); I. Pigment orange 2, C.I. I. Pigment orange 3, C.I. I. Β-naphthol pigments such as C.I. Pigment Orange 5; I. Pigment orange 4, C.I. I. Pigment orange 22, C.I. I. Pigment orange 24, C.I. I. Pigment orange 38, C.I. I. Naphthol AS pigments such as CI Pigment Orange 74; I. Isoindolinone pigments such as CI Pigment Orange 61; I. Perinone pigments such as C.I. Pigment Orange 43; I. Pigment orange 15, C.I. I. Disazo pigments such as CI Pigment Orange 16; I. Pigment orange 48, C.I. I. Quinacridone pigments such as CI Pigment Orange 49; I. Pigment orange 36, C.I. I. Pigment orange 62, C.I. I. Pigment orange 60, C.I. I. Pigment orange 64, C.I. I. An acetolone pigment such as C.I. Pigment Orange 72; I. Pigment orange 13, C.I. I. And pyrazolone pigments such as CI Pigment Orange 34.
Examples of the pigment exhibiting brown include C.I. I. Pigment brown 25, C.I. I. And naphthron pigments such as CI Pigment Brown 32.

Examples of pigments exhibiting black color include carbon black, titanium black, C.I. I. Indazine pigments such as CI Pigment Black 1 (aniline black); I. Pigment black 31, C.I. I. And perylene pigments such as CI Pigment Black 32. Among these, carbon black is preferable.
Examples of the white pigment include basic lead carbonate (2PbCO ₃ Pb (OH) ₂ , so-called silver white), zinc oxide (ZnO, so-called zinc white), titanium oxide (TiO ₂ , so-called titanium white), and titanium. Strontium acid (SrTiO ₃ , so-called titanium strontium white) can be used, and among these, titanium oxide is preferable. The inorganic particles used for the white pigment may be a simple substance or, for example, oxides such as silicon, aluminum, zirconium and titanium, organometallic compounds, and composite particles with organic compounds.

  Here, titanium oxide has a smaller specific gravity than other white pigments, a large refractive index, and is chemically and physically stable, so that it has a large hiding power and coloring power as a pigment. Excellent durability against other environments. Therefore, it is preferable to use titanium oxide as the white pigment. Of course, other white pigments (may be other than the listed white pigments) may be used as necessary.

Since the non-white pigment has a better color developability as the average particle size is smaller, if the pigment dispersion is applied to a pigment dispersion other than white, the average particle size of the pigment contained in the pigment dispersion is: The thickness is preferably about 0.01 μm to 0.4 μm, more preferably 0.02 μm to 0.3 μm.
The maximum particle diameter of the pigment is 3 μm or less, preferably 1 μm or less. The particle size of the pigment can be adjusted by selecting a pigment, a dispersant, a dispersion medium, setting dispersion conditions, and filtering conditions. Further, when the ink composition of the present invention is prepared as a white ink composition, the average particle size of the pigment contained in the pigment dispersion is 0.05 μm to The thickness is preferably about 1.0 μm, more preferably about 0.1 μm to 0.4 μm. Also when it is set as a white pigment dispersion, it is preferable that the maximum particle diameter of a pigment is 3 micrometers or less, Preferably it is 1 micrometer or less.

(Dispersant)
When a pigment is used as the colorant, a pigment dispersant may be used as necessary when preparing a dispersion of pigment particles. Examples of the pigment dispersant that can be used include higher fatty acid salts, Alkyl sulfate, alkyl ester sulfate, alkyl sulfonate, sulfosuccinate, naphthalene sulfonate, alkyl phosphate, polyoxyalkylene alkyl ether phosphate, polyoxyalkylene alkyl phenyl ether, polyoxyethylene polyoxypropylene Activators such as glycol, glycerin ester, sorbitan ester, polyoxyethylene fatty acid amide, amine oxide, or styrene, styrene derivatives, vinyl naphthalene derivatives, acrylic acid, acrylic acid derivatives, maleic acid, maleic acid derivatives, itaconic acid, itaconic acid Conductor, fumaric acid, block copolymer of two or more monomers selected from fumaric acid derivatives include random copolymers and salts thereof.

  A self-dispersing pigment can also be used in the ink composition of the present invention. The self-dispersing pigment as used in the present invention refers to a pigment that can be dispersed without a dispersant, and particularly preferably pigment particles having a polar group on the surface.

The pigment particles having a polar group on the surface as used in the present invention are a pigment whose surface is directly modified with a polar group, or an organic substance having an organic pigment mother nucleus, which is bonded directly or via a joint. (Hereinafter referred to as pigment derivative).
Examples of the polar group include a sulfonic acid group, a carboxylic acid group, a phosphoric acid group, a boric acid group, and a hydroxyl group, preferably a sulfonic acid group and a carboxylic acid group, and more preferably a sulfonic acid group.

  Examples of a method for obtaining pigment particles having a polar group on the surface include, for example, WO 97/48769, JP-A-10-110129, JP-A-11-246807, JP-A-11-57458, 11-189739, JP-A-11-323232, JP-A-2000-265094, etc., oxidize the pigment particle surface with an appropriate oxidizing agent, so that at least a part of the pigment surface has a sulfonic acid group or The method of introduce | transducing polar groups, such as the salt, is mentioned. Specifically, carbon black is oxidized with concentrated nitric acid, or in the case of a color pigment, oxidized with sulfamic acid, sulfonated pyridine salt, amidosulfuric acid or the like in sulfolane or N-methyl-2-pyrrolidone. Can be prepared. In these reactions, the pigment dispersion can be obtained by removing and purifying the substance that has been excessively oxidized and becomes water-soluble. Moreover, when a sulfonic acid group is introduced to the surface by oxidation, the acidic group may be neutralized with a basic compound as necessary.

  As other methods for obtaining pigment particles having polar groups on the surface, the pigment particles described in JP-A-11-49974, JP-A-2000-273383, JP-A-2000-303014, etc. are treated with a treatment such as milling. Examples thereof include a method of adsorbing on the surface, a method of dissolving a pigment together with a pigment derivative in a solvent, and a method of crystallizing in a poor solvent. Any method can easily obtain pigment particles having a polar group on the surface. be able to.

  The polar group on the pigment surface may be free or in a salt state, or may have a counter salt. Examples of the counter salt include inorganic salts (lithium, sodium, potassium, magnesium, calcium, aluminum, nickel, ammonium) and organic salts (triethylammonium, diethylammonium, pyridinium, triethanolammonium, etc.), preferably 1 A counter salt having a valence.

  The content of the colorant with respect to the total amount of the ink composition of the present invention is preferably 0.5% by mass to 10% by mass, and more preferably 0.5% by mass to 5% by mass.

As described above, the ink composition of the present invention can exhibit good performance even in a system that does not contain a polymerization initiator, but is applied to a system containing a polymerization initiator and other polymerizable compounds described later. May be.
(Polymerization initiator)
The ink composition of the present invention may contain one or more polymerization initiators as long as the effects of the present invention are not impaired. The polymerization initiator is preferably water-soluble, and the degree of water solubility is preferably 0.5% by mass or more, preferably 1% by mass or more, preferably 3% by mass in distilled water at 25 ° C. It is particularly preferable to dissolve the above. The polymerization initiator in the present invention may be a thermal polymerization initiator or a photopolymerization initiator, but is preferably a photopolymerization initiator. Moreover, it can be used even in a state where a non-aqueous polymerization initiator is dispersed.

  As the photopolymerization initiator in the present invention, it is preferable to use a polymerization initiator selected from the group consisting of α-hydroxyketones, α-aminoketones and acylphosphine oxides. Specifically, 1- [4- (2-hydroxyethyl) -phenyl] -2-hydroxy-2-methyl] -1-propan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2- A water-soluble polymerization initiator such as methyl-1-phenylpropan-1-one or a non-aqueous polymerization initiator of [bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide] can also be used. .

  Moreover, as a photoinitiator, you may use a commercial item, for example, Irgacure 29595 (brand name) (1- [4- (2-hydroxyethyl) -phenyl] -2-hydroxy-2-methyl]- 1-propan-1-one, manufactured by BASF), Darocur 1173 (trade name) (2-hydroxy-2-methyl-1-phenylpropan-1-one, manufactured by BASF), Irgacure 817DW (trade name) ([Bis An aqueous dispersion of (2,4,6-trimethylbenzoyl) -phenylphosphine oxide] manufactured by BASF).

  The content of the polymerization initiator in the ink composition of the present invention is preferably 0% by mass to 10% by mass, more preferably 0.1% by mass to 6% by mass with respect to the total amount of the ink composition, and 0.5 A mass% to 4 mass% is preferred.

[Radically polymerizable compound]
In addition to (a) the specific copolymer and (b) the specific diene compound, the ink composition of the present invention may further contain a radical polymerizable compound as long as the effects of the present invention are not impaired.

  The radically polymerizable compound used in the ink composition of the present invention is not limited as long as it is a compound in which a polymerization reaction proceeds by radicals.

  A radically polymerizable compound can be used 1 type or in mixture of multiple. Moreover, the radically polymerizable compound may be a monofunctional compound or a polyfunctional compound. When the proportion of the monofunctional compound is large, the cured product tends to be flexible, and when the proportion of the polyfunctional compound is large, the curability tends to be excellent. Accordingly, the ratio between the monofunctional compound and the polyfunctional compound is arbitrarily determined according to the application.

The radically polymerizable compound as an optional component that can be used in the present invention includes, for example, various known radically polymerizable compounds that cause a polymerization reaction by a partial structure represented by the general formula (1) and an initiation species generated from a polymerization initiator. Can be used.
As the radically polymerizable compound, not only a radically polymerizable monomer but also a radically polymerizable oligomer can be added. The radical polymerizable oligomer is a compound having at least one radical polymerizable group at the end of the oligomer and having a weight average molecular weight in the range of 400 to 10,000.

  Preferred examples of the radically polymerizable compound include compounds having an ethylenically unsaturated bond capable of radical polymerization. More specifically, it is a compound having at least one ethylenically unsaturated bond capable of radical polymerization in the molecule.

  Examples of radical polymerizable compounds include unsaturated carboxylic acids such as acrylic acid, methacrylic acid, itaconic acid, crotonic acid, isocrotonic acid, maleic acid, unsaturated carboxylic acid esters, and salts thereof; having an ethylenically unsaturated group Anhydrous; (meth) acrylamide; styrene derivatives; vinyl ethers, N-vinyl and the like.

  Examples of the radical polymerizable compound include a radical polymerizable monofunctional monomer and a radical polymerizable polyfunctional monomer.

  Examples of the radical polymerizable monofunctional monomer include acrylamide, 2-hydroxyethyl acrylamide, 2-hydroxymethyl acrylamide, t- in addition to the polymerizable compounds described in the following (2-1-1) to (2-1-27). Butylacrylamide, 3-dimethylaminopropylacrylamide, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, methoxy oligoethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, polyethylene glycol (meth) acrylate, tetrahydrofur Furyl acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and the like can be used.

  Radical polymerizable polyfunctional monomers include (meth) acrylates such as oligoethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, bis [2- (methacryloyloxy) ethyl] phosphate, and methylene bisacrylate. Known compounds such as acrylamides such as 4,7,10-trioxa-1,13-tridecanbisacrylamide and vinyl ethers such as triethylene glycol divinyl ether can be used.

  Moreover, although the following compounds are also mentioned as radically polymerizable polyfunctional monomers other than the above, this invention is not limited to these.

  As the radical polymerizable oligomer, it is preferable to use at least one selected from polyester oligomers, urethane oligomers, modified polyether oligomers, acrylic oligomers, and epoxy oligomers.

The radically polymerizable compound preferably has a (meth) acryloyloxy group or a (meth) acrylamide group, and more preferably has a plurality of (meth) acryloyloxy groups or (meth) acrylamide groups.
Here, the (meth) acryloyloxy group represents at least one of an acryloyloxy group and a methacryloyloxy group, and the (meth) acrylamide group represents at least one of an acrylamide group and a methacrylamide group.

  The radically polymerizable compound having a (meth) acryloyloxy group preferably used in the present invention is more preferably a compound represented by the following general formula (M-1).

In the general formula ^{(M-1), Q} 1 represents a ^{n 1} valent connecting ^{group, R 1 m} is a hydrogen atom or a methyl group. N ¹ represents an integer of 1 or more.

Compound represented by the general formula (M-1) are unsaturated monomers are those bound to the linking group Q ¹ by an ester bond. R ^1m represents a hydrogen atom or a methyl group, preferably a hydrogen atom. The valency ^{n 1} of the linking group ^{Q 1, n} 1 = 2 or more is ^{preferable, n} 1 = 2 or 6, more preferably ^{less, n} 1 = 2 to 4 is more preferred.

Furthermore, the linking group Q ¹ is not particularly limited as long as it is capable of linking groups and (meth) acryloyloxy structure. Specific examples include residues from which n ¹ hydrogen atoms or hydroxyl groups have been removed from the following compound group X.

-Compound group X-
Ethylene glycol, edylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,4-pentanediol, 1,3-pentanediol, 2,4-pentanediol, 3-methyl, 1,5- Pentanediol, 2-methyl, 2,4-pentanediol, 1,6-hexanediol, 1,5-hexanediol, 2,5-hexanediol, glycerin, 1,2,4-butanediol, 1,2, 5-pentanetriol, 1,2,6-hexanetriol, trimethylolpropane, tri Thiolethane, ditrimethylolpropane, ditrimethylolethane, thiodiglycol, neopentylglycol, pentaerythritol, dipentaerythritol, and their condensates, polyols such as sugars, ethylenediamine, diethylenetriamine, triethylenetetramine, polyethyleneimine, polypropylenediamine Such as polyamines.

  Furthermore, saturated or unsaturated such as methylene, ethylene, propylene, butylene group or the like substituted or unsubstituted alkylene chain having 4 or less carbon atoms, pyridine ring, imidazole ring, pyrazine ring, piperidine ring, piperazine ring, morpholine ring, etc. The functional group etc. which have the heterocyclic ring of can be illustrated.

Among these, the linking group Q ¹ is preferably a residue of a polyol containing an oxyalkylene group (preferably an oxyethylene group), and contains three or more oxyalkylene groups (preferably an oxyethylene group). A residue of a polyol is particularly preferable.

  The radically polymerizable compound having a (meth) acrylamide group preferably used in the present invention is more preferably a compound represented by the following general formula (M-2).

In the general formula ^{(M-2), Q} 2 represents a ^{n 2} divalent linking ^{group, R 2m} represents a hydrogen atom or a methyl group. N ² represents an integer of 1 or more.

The compound represented by formula (M-2), the unsaturated monomer, in which bonded to the linking group Q ² by an amide bond. R ^2m represents a hydrogen atom or a methyl group, and preferably a hydrogen atom. The valence ^{n 2} of the linking group ^{Q 2, n} 2 = 2 or more ^{preferably, n} 2 = 2 or 6, more preferably ^{less, n} 2 = 2 to 4 is more preferred.

The connecting group Q ² is not particularly limited as long as it is capable of linking groups and (meth) acrylamide structure. Specific examples include residues from which n ² hydrogen atoms or hydroxyl groups have been removed from the compound group X described above.

Among these, the linking group Q ² is preferably a residue of a polyol containing an oxyalkylene group (preferably an oxyethylene group), and contains 3 or more oxyalkylene groups (preferably an oxyethylene group). A residue of a polyol is particularly preferable.

  When the ink composition of the present invention further contains a radical polymerizable compound, the content ratio is preferably 20% by mass or less based on the total mass of the ink composition from the viewpoint of curability. It is more preferably at most 10 mass%, more preferably at most 10 mass%.

[Surfactant]
The ink composition of the present invention can contain a surfactant.
As surfactants preferably used, anionic surfactants such as dialkylsulfosuccinates, alkylnaphthalenesulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, Nonionic surfactants such as polyoxyethylene / polyoxypropylene block copolymers, and cationic surfactants such as alkylamine salts and quaternary ammonium salts. In particular, an anionic surfactant and a nonionic surfactant can be preferably used.

In the present invention, a polymer surfactant can also be used, and the following water-soluble resins are mentioned as preferred polymer surfactants. As the water-soluble resin, styrene-acrylic acid-acrylic acid alkyl ester copolymer, styrene-acrylic acid copolymer, styrene-maleic acid-acrylic acid alkyl ester copolymer, styrene-maleic acid copolymer are preferably used. Polymer, styrene-methacrylic acid-acrylic acid alkyl ester copolymer, styrene-methacrylic acid copolymer, styrene-maleic acid half ester copolymer, vinyl naphthalene-acrylic acid copolymer, vinyl naphthalene-maleic acid copolymer Etc.
In the present invention, a silicone surfactant having a polyalkylsiloxane, a fluorine surfactant having a fluorinated alkyl group, and the like can be preferably used. The fluorine-based surfactant is also available as a commercial product, and examples thereof include ZONYL FSN (trade name: Aldrich).

  In the ink composition of the present invention, when a surfactant is used, the content thereof is preferably 0.1% by mass or more and 5% by mass or less based on the solid content of the ink composition.

[Sensitizing dye]
In the present invention, a known sensitizing dye can be used in combination, and a sensitizing dye is preferably used in combination. As solubility of a sensitizing dye, what dissolve | melts 0.5 mass% or more at room temperature with distilled water is preferable, and what dissolve | melts 1 mass% or more is more preferable. Those that dissolve 3% by mass or more are particularly preferable. Further, as the sensitizing dye, a water-insoluble sensitizing dye can be dispersed and used.

  Examples of known sensitizing dyes that can be used in combination include N- [2-hydroxy-3- (3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy) propyl] -N, N, N. -Trimethylaluminum chloride, benzophenone, thioxanthone, anthraquinone derivatives and 3-acylcoumarin derivatives, terphenyl, styryl ketone and 3- (aroylmethylene) thiazoline, camphorquinone, eosin, rhodamine and erythrosine, and their modified forms And dispersions thereof. Moreover, the compound represented by the general formula (i) described in JP-A 2010-24276 and the compound represented by the general formula (I) described in JP-A-6-107718 can also be suitably used. .

  In addition to the components described above, the ink composition of the present invention has an object of improving ejection stability, print head and ink cartridge compatibility, storage stability, image storage stability, and other various performances as necessary. Depending on the type, various known additives such as viscosity modifiers, surface tension modifiers, specific resistance modifiers, film forming agents, preservatives, dispersants, UV absorbers, antioxidants, fading inhibitors, anticorrosives Agents, rust preventives, solid wetting agents, silica fine particles and the like can be appropriately selected and used. For example, oil droplet fine particles such as liquid paraffin, dioctyl phthalate, tricresyl phosphate, silicone oil, No. 5, JP-A 57-87988 and JP-A 62-261476, UV absorbers described in JP-A 57-74192, JP-A 57-87989, Japanese Patent Application Laid-Open No. 60-72785, Japanese Patent Application Laid-Open No. 61-14659, Japanese Patent Application Laid-Open No. 1-95091, Japanese Patent Application Laid-Open No. 3-13376, etc. JP-A 59-52689, JP-A 62-280069, JP-A 61-242871, JP-A 4-219266, and the like, optical brighteners, sulfuric acid, phosphoric acid, Examples include pH adjusters such as citric acid, sodium hydroxide, potassium hydroxide, and potassium carbonate.

<Method for Preparing Ink Composition>
The method for preparing the ink composition of the present invention is not particularly limited, and each component is mixed with a container drive medium mill such as a ball mill, a centrifugal mill or a planetary ball mill, a high-speed rotating mill such as a sand mill, or a medium agitation such as a stirring tank mill. It can be prepared by stirring, mixing and dispersing with a simple disperser such as a mill or a disper. About the addition order of each component, it is arbitrary. Preferably, a pigment, a polymer dispersant and an organic solvent are premixed and then subjected to a dispersion treatment, and the obtained dispersion is mixed together with a resin containing a specific copolymer, water, and an organic solvent. In this case, at the time of addition or after addition, the mixture is uniformly mixed with a simple agitator such as a three-one motor, a magnetic stirrer, a disper, or a homogenizer. You may mix using mixers, such as a line mixer. Further, in order to make the dispersed particles finer, they may be mixed using a dispersing machine such as a bead mill or a high-pressure jet mill. Depending on the type of pigment or polymer dispersant, a resin may be added during premixing before pigment dispersion.

  The ink composition of the present invention preferably has a surface tension at 25 ° C. of 20 mN / m to 40 mN / m. The surface tension is measured under the condition of 25 ° C. using an Automatic Surface Tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.). The viscosity is preferably 1 mPa · s to 40 mPa · s, and more preferably 3 mPa · s to 30 mPa · s. The viscosity of the ink composition is measured under conditions of 25 ° C. using VISCOMETER TV-22 (manufactured by TOKI SANGYOCO. LTD).

<Image forming method>
The image forming method of the present invention includes an ink application step of applying the ink composition of the present invention on a recording medium, and drying the ink composition applied on the recording medium using a heat source of 60 ° C. or higher. A drying step of removing at least a part of the liquid component contained in the composition; and an irradiation step of irradiating the applied and dried ink composition with active energy rays. By performing these steps, an image of the ink composition fixed on the recording medium is formed.

(Ink application process)
Hereinafter, the ink application process in the image forming method of the present invention will be described.
The ink application process in the present invention is not limited as long as it is a process of applying the ink composition of the present invention onto a recording medium.

  As an embodiment of applying the ink composition of the present invention on a recording medium, an embodiment of applying an ink composition by an inkjet method onto a recording medium is particularly preferable.

  In the image forming method of the present invention, the ink jet recording apparatus used when the ink jet method is applied in the ink application process is not particularly limited, and a known ink jet recording apparatus capable of achieving the target resolution is arbitrarily selected. Can be used. That is, any known inkjet recording apparatus including a commercially available product can discharge the ink composition onto the recording medium in the image forming method of the present invention.

Examples of the ink jet recording apparatus that can be used in the present invention include an apparatus including an ink supply system, a temperature sensor, and a heating unit.
Examples of the ink supply system include an original tank containing the ink composition of the present invention, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, a piezo-type inkjet head, and the like. The piezo-type inkjet head preferably has a multi-size dot of 1 to 100 pl, more preferably 8 to 30 pl, preferably 320 × 320 to 4,000 × 4,000 dpi (dot per inch), more preferably 400 × 400. ˜1,600 × 1,600 dpi, more preferably 720 × 720 dpi. The dpi referred to in the present invention represents the number of dots per 2.54 cm (1 inch).

In the ink application step, it is desirable that the discharged ink composition has a constant temperature. Therefore, the ink jet recording apparatus preferably includes a means for stabilizing the ink composition temperature. The parts to be kept at a constant temperature are all the piping systems and members from the ink tank (intermediate tank if there is an intermediate tank) to the nozzle ejection surface. That is, heat insulation and heating can be performed from the ink supply tank to the inkjet head portion.
The temperature control method is not particularly limited, but for example, it is preferable to provide a plurality of temperature sensors in each piping portion and perform heating control according to the flow rate of the ink composition and the environmental temperature. The temperature sensor can be provided near the ink supply tank and the nozzle of the inkjet head. Moreover, it is preferable that the head unit to be heated is thermally shielded or insulated so that the apparatus main body is not affected by the temperature from the outside air. In order to shorten the printer start-up time required for heating or to reduce the loss of thermal energy, it is preferable to insulate from other parts and reduce the heat capacity of the entire heating unit.

  The ink composition is discharged using the ink jet recording apparatus, and the ink composition is preferably heated to 25 to 80 ° C., more preferably 25 to 50 ° C., and the viscosity of the ink composition is preferably 3 mPa · s to It is preferable to carry out after lowering to 15 mPa · s, more preferably 3 mPa · s to 13 mPa · s. In particular, it is preferable to use an ink composition having a viscosity of 50 mPa · s or less at 25 ° C. as the ink composition of the present invention, since it can be discharged satisfactorily. By using this method, high ejection stability can be realized.

  The temperature of the ink composition during ejection is preferably constant, and the control range of the temperature of the ink composition is more preferably ± 5 ° C. of the set temperature, more preferably ± 2 ° C. of the set temperature, and most preferably set. A temperature of ± 1 ° C. is appropriate.

In the present invention, the recording medium is not particularly limited, and a known recording medium can be used as a support or a recording material. Examples of the recording medium include paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, polyvinyl chloride resin, two Cellulose acetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic on which the above metals are laminated or deposited A film etc. are mentioned.
Since the ink composition of the present invention contains (a) a specific copolymer and can suppress bleeding, it can be suitably used for non-permeable recording media. Here, the non-permeable recording medium means a recording medium having such a property that the ink composition does not penetrate inside when the ink composition is applied to the surface.
The non-permeable recording medium is preferably a plastic substrate such as polyvinyl chloride, polyethylene terephthalate, or polyethylene, more preferably a polyvinyl chloride resin substrate, and even more preferably a polyvinyl chloride resin sheet or film.

(Drying process)
The image forming method of the present invention further includes an ink drying step (also referred to as “heat drying step”) after the ink application step and before the irradiation step. The drying step is a step in which the ink composition applied on the recording medium is dried using a heat source of 60 ° C. or higher to remove at least a part of the liquid component contained in the ink composition. "Does not necessarily mean that a liquid component such as a solvent is completely removed. The upper limit of the temperature of the heat source is not particularly limited, but when a resin sheet or the like is used as a non-absorbent recording medium, it is preferably 120 ° C. or lower from the viewpoint of suppressing deformation of the recording medium, and 100 ° C. More preferably, it is as follows.
In the heating and drying process, the ink composition discharged onto the recording medium is heated by (c) the organic solvent and water used in combination as needed, and the amount of liquid contained in the ink composition is reduced. Is done.

A process of heating and drying the discharged ink composition of the present invention (heat drying process) will be described.
The heating means is not particularly limited as long as (c) the organic solvent and water used in combination can be dried as necessary, and is not particularly limited. Non-contact heating by wind, infrared lamp, heat oven or the like can be used. In the case of non-contact heating, heating is usually performed from the ink image forming surface side, but heating may also be performed from the non-forming surface of the ink image, or heating may be performed by transporting through the heating zone.
The heating temperature is 60 ° C or higher, more preferably about 60 ° C to 100 ° C, and still more preferably about 60 ° C to 80 ° C. The temperature of the ink image rises by the heat drying step, and is represented by (a) the partial structure represented by the general formula (1) in the specific copolymer and (b) the general formula (2) of the specific diene compound. A Diels-Alder reaction occurs between the conjugated diene structure and a crosslinked structure is formed. Since this reaction is an exothermic reaction, the Diels-Alder reaction itself is sequentially promoted and the reaction proceeds in a chain and the temperature of the ink image rises. Therefore, the curing reaction by the subsequent exposure is efficiently advanced. The For this reason, the curing reaction proceeds with high sensitivity even by low energy exposure.
In this specification, the heating temperature in the drying step is a value obtained by measuring the temperature of the support surface. The surface temperature of the support is measured by a conventional method using a contact thermocouple thermometer, a non-contact thermometer, or the like.
The drying / heating time can be appropriately set in consideration of the composition and printing speed of the ink composition to be used.

The ink composition in which the organic solvent and the like are reduced by the drying process is further photofixed by irradiating active energy rays in the irradiation process.
(Irradiation process)
Hereinafter, the irradiation step in the image forming method of the present invention will be described.
The irradiation step in the present invention is not limited as long as it is a step of irradiating the ink composition applied on the recording medium with active energy rays.

  Examples of active energy rays that can be used in the irradiation step include ultraviolet rays (hereinafter also referred to as UV light), visible light glands, electron beams, and the like, and UV light is preferably used.

  Although the peak wavelength of UV light depends on the absorption characteristics of the sensitizing dye used as necessary, it is preferably, for example, 200 nm to 405 nm, more preferably 220 nm to 390 nm, and 220 nm to 350 nm. More preferably. In this invention, when not using a sensitizing dye and a photoinitiator together, it is preferable that it is 200 nm-310 nm, and 200 nm-280 nm are more preferable.

UV light is the illumination intensity on the exposed surface is, for ^{example, 10mW / cm 2 ~2,000mW / cm} 2, ^is preferably a suitably be irradiated with ^{20mW / cm 2 ~1,000mW / cm 2} . In addition, as described above, in the crosslinking reaction is accelerated by the drying process, for ^example, be efficiently curing reaction proceeds even by 20mW / cm ² ~400mW / cm 2 as low energy deposition invention It can be said that it is one of the features.

  As the UV light source, a mercury lamp, a gas / solid laser or the like is mainly used, and a mercury lamp, a metal halide lamp and a UV fluorescent lamp are widely known. In addition, replacement with GaN-based semiconductor ultraviolet light-emitting devices is very useful industrially and environmentally. LED (UV-LED) and LD (UV-LD) are small, have long life, high efficiency, and low cost. Yes, it is expected as a UV light source. In the present invention, when a sensitizing dye and a photopolymerization initiator are used in combination, a metal halide lamp, a high pressure mercury lamp, a medium pressure mercury lamp, a low pressure mercury lamp, and a UV-LED are preferable, and a sensitizing dye and a photopolymerization initiator are used in combination. If not, a medium pressure mercury lamp or a low pressure mercury lamp is preferred, and a low pressure mercury lamp is particularly preferred.

In the irradiation step, the ink composition of the present invention applied on the recording medium is irradiated with such UV light, for example, for 0.01 seconds to 120 seconds, preferably 0.1 seconds to 90 seconds. Is appropriate.
As the irradiation conditions and the basic irradiation method, the irradiation conditions and the irradiation method disclosed in JP-A-60-132767 can be similarly applied to the present invention. Specifically, a method in which a light source is provided on both sides of a head unit including an ink ejection device and the head unit and the light source are scanned by a so-called shuttle method, or a method in which a separate light source without driving is used is preferable. The irradiation with the active energy ray is performed after a certain period of time (for example, 0.01 seconds to 120 seconds, preferably 0.01 seconds to 60 seconds) after ink landing and heat drying.

[Printed matter]
The printed matter of the present invention is characterized by having an image formed by the ink composition of the present invention or an image formed by the image forming method of the present invention. The printed matter of the present invention has an image with reduced bleeding and excellent solvent resistance.
For this reason, the ink composition of the present invention or the printed product of the present invention can be suitably used for forming molded articles that are subjected to heat molding in addition to general applications.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, “part” and “%” are based on mass.

Specific copolymers A-1 to A-5, comparative polymer C-1, specific diene compounds B-1 and B-2 used in the examples were synthesized as follows.
The specific copolymers A-1 to A-6 are the compounds listed above as exemplary compounds A-1 to A-6 of the specific copolymer. The structures of the specific diene compounds B-1 to B-3 are shown below.

[Synthesis Example 1: Synthesis of specific copolymers A-1 to A-5]
<Synthesis of Monomers 1 and 2>
Toluene 75 g and dimethylmaleic anhydride 42.0 g (manufactured by Sigma-Aldrich Japan) were introduced into a 500 ml three-necked flask equipped with a Dean-Stark distillation tube and stirred with a stirrer (Shinto Kagaku Co., Ltd .: Three-One Motor). While heating, the temperature was raised to 50 ° C. 2-Amino-1-propanol (25.0 g) was added dropwise over 30 minutes, followed by stirring for 4 hours. After dropping the temperature to 60 ° C, 0.042 g of p-methoxyphenol (Wako Pure Chemical Industries) and 6.2 g of sulfuric acid (Wako Pure Chemical Industries) are added, and 43.0 g of methacrylic acid (Wako Pure Chemical Industries) is added in 30 minutes. It was dripped. After completion of the dropwise addition, the temperature was raised until the solvent was refluxed, and the reaction was performed for 3 hours. The reaction solution was neutralized with 29 g of a 50 w / v% aqueous sodium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd.), and 200 ml of toluene and 100 ml of water were added to separate the solution. The organic layer was washed twice with saturated brine, 30 mg of p-methoxyphenol was added to the organic layer, and the solvent was distilled off under reduced pressure in vacuo to obtain 64.5 g of monomer 1.
The monomer 3 was synthesized in the same manner using 6-aminopropanol instead of 3-amino-1-propanol used in the synthesis of the monomer 1. The production of each target product was confirmed by ¹ H NMR.

<Synthesis of Specific Copolymer A-1>
2-pyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd.) 20 g was added to a three-necked flask equipped with 200 mL of the above stirrer substituted with nitrogen. After heating to 80 ° C. under a nitrogen stream, 20 g of 2-pyrrolidone, 10.0 g of the monomer 1 6.8 g of n-butyl methacrylate (manufactured by Wako Pure Chemical Industries), 3.2 g of methacrylic acid, 3-mercaptopropionic acid 0 A mixed solution of 0.030 g (manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.079 g of dimethyl 2,2′-azobisisobutyrate (manufactured by Wako Pure Chemical Industries, Ltd.) was added dropwise over 3 hours. After dropping, 2 hours and 4 hours later, 0.050 g of dimethyl 2,2′-azobisisobutyrate was added, and the reaction was further performed for 2 hours. Next, 30 g of the obtained solution in a 200 ml eggplant-shaped flask, 0.70 g of sodium bicarbonate (manufactured by Wako Pure Chemical Industries) and 20 g of water were added and stirred at 60 ° C. After dissolution of the polymer, the solid content was adjusted to 20% by addition of water to obtain an aqueous solution of the specific copolymer A-1. Further, the solution after polymerization was measured by GPC, and it was confirmed that the weight average molecular weight was 72,300.

<Synthesis of Specific Copolymers A-2 to A-6>
About specific copolymer A-2-A-6, it polymerizes by adjusting the quantity of a raw material monomer and a mercaptopropionic acid suitably so that it may become the structure described as structural formula of each copolymer, and predetermined neutralization The amount of sodium hydrogen carbonate was adjusted so as to obtain a 20% aqueous solution.

[Synthesis Example 2: Synthesis of Comparative Polymer C-1]
7.00 g of 2-pyrrolidone was added to a three-necked flask equipped with 500 mL of the agitator purged with nitrogen. After raising the temperature to 80 ° C. under a nitrogen stream, a mixed solution of 7.0 g of 2-pyrrolidone, 10.0 g of methacrylic acid, 0.022 g of 3-mercaptopropionic acid, and 0.02 g of dimethyl 2,2′-azobisisobutyrate is taken over 2 hours. And dripped. After dropping, 2 hours and 4 hours later, 0.013 g of dimethyl 2,2′-azobisisobutyrate was added, and the reaction was further carried out at 90 ° C. for 2 hours. Subsequently, 8.75 g of glycidyl methacrylate, 0.05 g of tetrabutylammonium bromide, 0.05 g of p-methoxyphenol and 15.0 g of 2-pyrrolidone were added and reacted at 60 ° C. for 2 hours. Further, 4.59 g of sodium hydrogen carbonate, 40.1 g of water and 11.1 g of 2-pyrrolidone were added, heated at 50 ° C. for 2 hours, and 20% aqueous solution of comparative polymer C-1 (structure will be described later). Got.

[Synthesis Example 3: Synthesis of Specific Diene Compounds B-1 and B-2, Acquisition of Specific Diene Compound B-3]
Except for using furfuryl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) as a monomer having a furan group, a polymer B- having the following structure was synthesized in the same manner as the polymer A-1 shown in Synthesis Example 1. 1 and polymer B-2 were synthesized. The obtained specific diene compounds B-1 and B-2 were subjected to ¹ H-NMR and GPC measurements to produce a polymer with the desired structure, the weight average molecular weight of B-1 was 21,000, B- 2 was confirmed to be 35,000.
As the specific diene compound B-3, 2,2-di (2-furyl) propane (manufactured by Tokyo Chemical Industry Co., Ltd.) was used.

[Preparation of magenta pigment dispersant]
Magenta pigment CINQUASIA MAGENTA RT355 (mixed crystal of quinacridone, manufactured by BASF) 40 parts by mass, diethylene glycol diethyl ether (manufactured by Wako Pure Chemical Industries, Ltd.) 49 parts by mass, SOLPERSE 32000 (trade name: polyester polymer dispersant, Nippon Lubrizol) 11 parts by mass was stirred with a stirrer until uniform, and a pigment preliminary dispersion was prepared. The obtained preliminary dispersion was further dispersed in a vertical bead mill (manufactured by IMEX Co., Ltd., Ready Mill) using 0.1 mm zirconia beads for 3 to 6 hours to prepare a magenta pigment dispersion. When the volume average particle diameter of the pigment particles in the obtained pigment dispersion is measured by a dynamic light scattering method using a nanotrack particle size distribution measuring device UPA-EX150 (manufactured by Nikkiso Co., Ltd.), It was 180 nm. When this pigment dispersion is used, it is described as “M dispersion” in Tables 1 and 2 below.
As other colorants, the following commercial products were used.
-Magenta pigment dispersion with a solid content concentration of 14% (trade name: Projet Magenta APD 1000, manufactured by FUJIFILM Imaging Colorant Co., Ltd.)
-Cyan pigment dispersion having a solid content of 14% (trade name: Projet Cyan APD 1000 (manufactured by FUJIFILM Imaging Colorant Co., Ltd.)
Black pigment dispersion (trade name: Projet Black APD 1000, manufactured by Fuji Film Imaging Colorant Co., Ltd.)
-Yellow pigment dispersion with a solid content of 14% (trade name: Projet Yellow APD 1000, manufactured by Fuji Film Imaging Colorant Co., Ltd.)

[Examples 1 to 13, Comparative Examples 1 to 5]
1. Preparation of ink composition (a) Specific copolymer or comparative polymer compound, (b) Specific diene compound, (c) Organic solvent, (d) Water, (e) Colorant, Surfactant -The composition shown in Table 2 was mixed and stirred at 250 rpm using a mixer (Silverson L4R) to prepare crude ink compositions.
Each obtained crude ink composition is packed in a plastic disposable syringe and filtered through a polyvinylidene fluoride (PVDF) pore size 5 μm filter (Millex-SV, Millipore, diameter 25 mm) to obtain a finished product. Ink compositions of Examples 1 to 13 and Comparative Examples 1 to 8 were obtained.

[Examples 14-15, Comparative Examples 6-7]
1. Preparation of ink composition (a) Specific copolymer or comparative polymer compound, (b) Specific diene compound, (c) Organic solvent, (e) Colorant (Silverson Co., Ltd. L4R) was used for mixing and stirring at 250 revolutions / minute to prepare crude ink compositions.
Each obtained crude ink composition is packed in a plastic disposable syringe and filtered through a polyvinylidene fluoride (PVDF) pore size 5 μm filter (Millex-SV, Millipore, diameter 25 mm) to obtain a finished product. Ink compositions of Examples 14 to 15 and Comparative Examples 6 to 7 were obtained.

  “-” In Tables 1 and 2 indicates that the components shown in the corresponding column are not contained in the ink composition.

The detail of each compound used for Examples 1-15 and Comparative Examples 1-7 is shown below.
In addition, the composition ratio of each structural unit written together in the (a) specific copolymer and comparative polymer shown below is a mass reference | standard.

<(A) Specific copolymer>
The specific specific copolymers A-1 to A-6 obtained in Synthesis Example 1 were used.

<Comparative polymer>
The comparative polymer C-1 (the following structure) obtained in Synthesis Example 2 was used.

<(B) Specific diene compound>
The structures of the specific diene compounds B-1 and B-2, which are high molecular compounds obtained in Synthesis Example 2, and the specific diene compound B-3, which is a low molecular compound, are shown below.

(C) Organic solvent 2-pyrrolidone (manufactured by Wako Pure Chemical Industries, Ltd.)
・ Γ-butyrolactone (manufactured by BASF Japan Ltd.)
・ 2-Methyl-1,3-propanediol (manufactured by Tokyo Chemical Industry Co., Ltd.)
・ Diethylene glycol diethyl ether (manufactured by Tokyo Chemical Industry Co., Ltd.)

<(D) Water>
(D) Ion exchange water was used as water.

<Surfactant>
・ ZONYL FSN (trade name: Fluorosurfactant, Aldrich)

When the viscosity of the ink composition of each obtained Example was measured using VISCOMETER TV-22 (made by TOKI SANGYOCO.LTD), all were in the range of 4 mPa * s-10 mPa * s at room temperature (25 degreeC). there were.
Moreover, when the surface tension of the obtained ink composition of each Example was measured using Automatic Surface Tensiometer CBVP-Z (manufactured by Kyowa Interface Science Co., Ltd.), all were 20 mN / m at room temperature (25 ° C.). The range was ˜40 mN / m.

2. Evaluation The following evaluations were performed using the ink compositions obtained in Examples and Comparative Examples. The evaluation results are shown in Tables 1 and 2.

<Bludge suppression evaluation>
A commercially available inkjet printer (manufactured by Fuji Film Dimatics, product name: DMP-2831) was prepared as an inkjet recording apparatus.
Each obtained ink composition was loaded into the above-described ink jet printer and heated at 35 ° C., and the width in a direction perpendicular to the head scanning direction on a polyvinyl chloride substrate (Avery 400 GLOSS WHITE PERMANENT, manufactured by Avery Dennison) Twenty straight lines having a length of 100 μm and a length of 1 cm were printed at intervals of 100 μm. The shape of the obtained straight line was visually observed and evaluated according to the following criteria. Note that the levels of A and B are levels that have no practical problem.
-Evaluation criteria-
A: The linearity is high and the edge is hardly disturbed.
B: The edge of a straight line is slightly disturbed but not mixed with the adjacent straight line.
C: A thing with a large blur and a part mixed with the adjacent straight line.

<Solvent resistance evaluation>
Each of the obtained ink compositions was subjected to No. of K hand coater manufactured by RK PRINT COAT INSTRUMENTS. Using 2 bars, it was applied to an 8 cm square vinyl chloride sheet (Avery 400 GLOSS WHITE PERMANENT, manufactured by Avery Dennison Co., Ltd.) with a thickness of 12 μm. Further, after moisture was dried at 60 ° C. for 3 minutes, exposure was performed with a low-pressure mercury lamp under the condition of an energy of 1000 mJ / cm ² to obtain a printed matter having a cured film (solid image) on the vinyl chloride sheet.
The surface on the side having the cured film (image) in the obtained printed material was rubbed with a cotton swab impregnated with isopropyl alcohol and evaluated according to the following evaluation criteria. In addition, A and B are levels with no practical problem.
-Evaluation criteria-
A: No change was observed in the image even after rubbing 50 times or more.
B: The image density decreased after 20 to 49 rubbing.
C: The image density decreased after rubbing 10 to 19 times.
D: The image density was remarkably lowered after 0 to 9 rubbing.

<Low illuminance solvent resistance evaluation>
The obtained ink compositions of Examples and Comparative Examples were used as No. of K hand coater manufactured by RK PRINT COAT INSTRUMENTS. Using 2 bars, it was applied to an 8 cm square vinyl chloride sheet (Avery 400 GLOSS WHITE PERMANENT, manufactured by Avery Dennison Co., Ltd.) with a thickness of 12 μm. Furthermore, after moisture was dried at 70 ° C. for 3 minutes, exposure was performed with a low-pressure mercury lamp under the condition of an energy of 400 mJ / cm ² to obtain a printed matter having a cured film (solid image) on the vinyl chloride sheet.
The surface on the side having the cured film in the obtained printed material was rubbed with a cotton swab impregnated with isopropyl alcohol and evaluated according to the following evaluation criteria. The evaluation results are shown in the table. In addition, A and B are levels with no practical problem.
A: No change was observed in the image even after rubbing 50 times or more.
B: The image density decreased after 20 to 49 rubbing.
C: The image density decreased after rubbing 10 to 19 times.
D: The image density was remarkably lowered after 0 to 9 rubbing.

<Dischargeability>
As an inkjet recording apparatus, a commercially available inkjet printer (product name: DMP-2831 manufactured by FUJIFILM Dimatics) was used, and on a polyvinyl chloride substrate (Avery 400 GLOSS WHITE PERMANENT, manufactured by Avery Dennison) A solid image of 20 cm × 20 cm was printed. The formed image was visually evaluated according to the following evaluation criteria.
-Evaluation criteria-
A: No dot defect due to defective ejection was observed, and a good image was obtained.
B: The occurrence of dot missing due to ejection failure was slightly observed, but it was of a level that would not cause any practical problems.
C: An image that could not be put to practical use was generated due to occurrence of missing dots due to ejection failure.

  As shown in Tables 1 and 2, each of the ink compositions of Examples containing (a) a specific copolymer and (b) a specific diene compound bleeds in comparison with the ink composition of Comparative Example. It can be seen that an image formed by low-illuminance exposure exhibits excellent solvent resistance, as well as excellent suppression and solvent resistance.

Claims (11)

(A) a polymer compound containing a repeating unit having a partial structure represented by the following general formula (1), (b) a compound having two or more partial structures represented by the following general formula (2) in the molecule, And (c) an active energy ray-curable ink composition containing an organic solvent.


(In General Formula (1), R ^a and R ^b each represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and at least one of R ^a and R ^b represents an alkyl group having 1 to 4 carbon atoms. R ^a and R ^b may be bonded to each other to form a 4- to 6-membered alicyclic structure, and * represents a bonding site with a main chain or a side chain in the polymer compound.


(In General Formula (2), R ¹ and R ² each independently represents an alkyl group, an alkoxy group, or an acyloxy group, or R ¹ and R ² are bonded to each other to form a ring, Represents a divalent linking group selected from an alkylene group and —O—, and R ¹ and R ² are not single bonds, and R ³ , R ⁴ , R ⁵ and R ⁶ are each independently In the compound which represents a hydrogen atom, an alkyl group, an alkoxy group, or an acyloxy group, and any one of R ³ and R ⁴ has two or more partial structures represented by (b) general formula (2) in the molecule. Represents a single bond or a divalent linking group bonded to another partial structure, and two or more of R ³ , R ⁴ , R ⁵ and R ⁶ are not bonded to each other to form a ring. 2. The active energy ray curing according to claim 1, wherein the compound (b) having two or more partial structures represented by the general formula (2) in the molecule is a polymer compound containing a repeating unit having a conjugated diene structure. Type ink composition. The polymer compound containing the repeating unit (a) having a repeating unit having a partial structure represented by the general formula (1) is a polymer compound containing a repeating unit represented by the following general formula (3). Item 3. The active energy ray-curable ink composition according to Item 2.


(In the general formula (3), ^{R a} and ^{R b} are the same meanings as ^{R a} and ^{R b} in the general formula (1) .R ^c is .Z represents a hydrogen atom or a methyl group, a single bond, -COO-** or -CONR ^d -**, R ^d represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and ** represents a bonding position to X. X is a straight chain or branched Alternatively, it represents an alkylene group having a cyclic structure, and the alkylene group may contain —O— in the alkylene chain, and may be substituted with an alkyl group having 4 or less carbon atoms . The active energy ray-curable ink composition according to claim 1, further comprising (d) water. (A) The polymer compound containing a repeating unit having a partial structure represented by the general formula (1) is at least one selected from alcoholic hydroxyl groups, alkyl-substituted carbamoyl groups, carboxyl groups, sulfo groups, and salts thereof. The active energy ray-curable ink composition according to any one of claims 1 to 4, further comprising a repeating unit having a hydrophilic group. (B) A polymer compound in which the compound having two or more partial structures represented by the general formula (2) in the molecule includes a repeating unit having a partial structure represented by the following general formula (2-1) The active energy ray-curable ink composition according to any one of claims 1 to 5.
In the following general formula (2-1), * represents a binding site with a repeating unit.

The active energy ray-curable ink composition according to any one of claims 1 to 6, further comprising (e) a colorant. The active energy ray-curable ink composition according to any one of claims 1 to 7, which is for inkjet recording. The active energy ray-curable ink composition according to any one of claims 1 to 8, which is used for printing on a non-permeable recording medium. An ink application step of applying the ink composition according to any one of claims 1 to 9 onto a recording medium;
A drying step of drying the ink composition applied on the recording medium using a heat source of 60 ° C. or higher to remove at least part of the liquid component contained in the ink composition;
And an irradiation step of irradiating the ink composition applied to the recording medium and dried with an active energy ray. On a recording medium, printed matter having images formed by the active energy ray-curable ink composition according to any one of claims 1 to 9.