JP2007099836A - Ink composition, ink set and ink-jet image printing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ink set maintaining its long-term storage stability and excellent fixability and enabling high-quality printed images to be formed. <P>SOLUTION: An ink composition is provided, being characterized by containing a compound ≤1,000 in molecular weight having two or more carbamoyl groups. The ink set comprises multiple liquids comprising at least a first liquid and a second liquid, wherein the first liquid contains the compound ≤1,000 in molecular weight having two or more carbamoyl groups. An ink-jet image printing method is also provided, comprising the following practice: Using the above ink set, the first and the second liquids are simultaneously applied on a printing medium, or either one of them is applied and the other is then applied, thus forming printed images. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ink composition, an ink set, and an image recording method, and in particular, can form an ink composition, an ink set, and a high-quality image used in a multi-liquid aggregation type inkjet image recording method. The present invention relates to a possible image recording method.

  An ink jet system that discharges ink from an ink discharge port such as a nozzle is small and inexpensive, and is used in many printers because it can form an image without contact with a print medium. Among these ink jet systems, the piezoelectric ink jet system that ejects ink using deformation of piezoelectric elements and the thermal ink jet system that ejects ink using the boiling phenomenon of ink due to thermal energy are excellent in high resolution and high speed printability. Has characteristics.

  Currently, high speed and high image quality are important issues when printing on non-water-absorbing recording media such as plain paper or plastic with an inkjet printer. In particular, if it takes a long time to dry the droplets after printing, image bleeding tends to occur, and droplet ejection interference occurs due to mixing between adjacent ink droplets, which not only prevents sharp image formation. In the case of using a non-water-absorbing recording medium, there is a practical problem such that it is necessary to dry without overlapping the recorded matter immediately after printing because the drying of the solvent is extremely slow.

  Ink jet ink that is cured and fixed by radiation rather than volatilization of the ink solvent has been proposed as one of the methods for accelerating the curing of the ink in order to suppress image bleeding and droplet ejection interference (for example, Patent Document 1). reference.). However, since the pigment dispersion is used as the coloring component, the nozzles are clogged due to the aggregation of the pigment, and it is difficult to discharge the ink stably.

  For this reason, in order to perform image formation excellent in transparency and color tone without using a pigment, an ultraviolet curable ink using a dye as a colorant is also disclosed (for example, see Patent Document 2). This ink has a problem that an undesirable polymerization reaction easily occurs during storage and storage stability is not sufficient. Furthermore, since conductive salts are contained and the solubility in these inks may be poor, there is a concern of poor printing due to precipitation in a long-term storage state.

  For the purpose of achieving both storage stability and high-speed drying properties, a technique has been proposed in which a two-component ink is used to react both on a recording medium. For example, after a liquid having a basic polymer is adhered, A method for recording an ink containing a dye (for example, see Patent Document 3), a method for applying an ink containing an anionic compound and a colorant after applying a liquid composition containing a cationic substance (for example, a patent) Reference 4), and a recording method using an ink containing a photocurable resin on one side and a photopolymerization initiator on the other (for example, see Patent Document 5).

  However, these methods are intended to suppress blurring of the image by precipitation of the dye itself, and cannot sufficiently prevent deterioration in image quality due to droplet ejection interference. Ink-jet recording continuously discharges ink (liquid) droplets as droplet n1, droplet n2, droplet n3,..., Droplet nx, and droplets n1 and droplets on a recording medium. n2, droplet n3,... forms a line or image with the droplet nx. In this case, droplet ejection interference refers to droplets that are deposited adjacent to each other. This is a phenomenon in which the droplets n1 and n2 (for example, the droplets n1 and n2) are united to reduce the surface energy (to reduce the surface area). Since the movement of the droplets occurs when adjacent droplets coalesce, deviation from the landing position, particularly when a thin line is drawn with ink containing a colorant, non-uniform line width occurs. Furthermore, the ejected ink liquid tends to diffuse on the recording medium over time, and when the time to cure by actinic rays is long, the dot diameter becomes larger than the intended one, and is formed with dots. There was a problem that the line to be thickened.

Further, the method as described in Patent Document 3 includes an aqueous solvent, so that the drying speed is slow, and the precipitated dye is likely to be unevenly distributed on the recording medium, which may cause deterioration in image quality. .
Japanese Patent Laid-Open No. 5-214279 U.S. Pat. No. 4,303,924 Japanese Unexamined Patent Publication No. 63-60783 JP-A-8-174997 Japanese Patent No. 3478495

Another object of the present invention is to maintain long-term storage stability and excellent fixability, as well as blurring and changes in droplet ejection shape (line width) that may occur when a time interval is left until exposure after printing. An object of the present invention is to provide an ink set capable of forming a high-quality image and an ink composition used for the ink set.
Another object of the present invention is to suppress bleeding and change in droplet ejection shape (thickening of the line width) that may occur when the time interval until exposure after printing is maintained while maintaining excellent fixability. Another object of the present invention is to provide an ink jet image recording method capable of forming a high-quality image having no stickiness and excellent scratch resistance.

The object is achieved by the present invention described below.
That is, the present invention
<1> An ink composition comprising a compound having two or more carbamoyl groups and having a molecular weight of 1,000 or less.

<2> The ink composition according to <1>, wherein the compound having two or more carbamoyl groups and having a molecular weight of 1,000 or less is a compound represented by the following general formula (1) or (2): It is a thing.

(In the general formulas (1) and (2), R _{1 to} R ₈ each independently represents a hydrogen atom, an alkyl group or an aryl group. L ₁ represents an n + 1 valent linking group, and L ₂ represents an m + 1 valent linking group. M and n represent an integer of 1 or more.)

<3> At least _one of R ₁ and R ₄ in the general formula (1) or at least one of R ₆ and R ₇ in the general formula (2) is a hydrogen atom <2 >.
<4> The ink composition according to any one of <1> to <3>, which contains a polymerization initiator.

<5> The ink composition according to any one of <1> to <4>, which contains a high-boiling organic solvent that satisfies the following conditions (1) and (2).
Condition (1): The viscosity at 25 ° C. is 100 mPa · s or less, or the viscosity at 60 ° C. is 30 mPa · s or less.
Condition (2): The boiling point is higher than 100 ° C.
<6> The ink composition according to any one of <1> to <5>, wherein the ink is for inkjet recording.

<7> An ink set including at least a first liquid and a second liquid and including a plurality of types of liquids, wherein the first liquid contains a compound having a molecular weight of 1000 or less and having two or more carbamoyl groups. This is an ink set.
<8> The ink set according to <7>, wherein the compound having two or more carbamoyl groups and having a molecular weight of 1,000 or less is a compound represented by the following general formula (1) or (2): .

(In the general formulas (1) and (2), R _{1 to} R ₈ each independently represents a hydrogen atom, an alkyl group or an aryl group. L ₁ represents an n + 1 valent linking group, and L ₂ represents an m + 1 valent linking group. M and n represent an integer of 1 or more.)

<9> At least _one of R ₁ and R ₄ in the general formula (1) or at least one of R ₆ and R ₇ in the general formula (2) is a hydrogen atom <8 > Ink set described in the above.
<10> The ink according to any one of <7> to <9>, wherein the second liquid contains a polymerizable or crosslinkable material (hereinafter collectively referred to as a polymerizable compound). Is a set.

<11> The ink set according to any one of <7> to <10>, wherein the second liquid contains a colorant.
<12> The content of the colorant in the first liquid is an amount that is 0 or more and 0.5 or less in terms of the solution absorbance at the maximum absorption wavelength when the ink solution having a thickness of 1 cm is transmitted. The ink set according to any one of <7> to <11>, which is characterized.

<13> At least one of the first liquid and the second liquid contains a high-boiling organic solvent that satisfies the following conditions (1) and (2): <7> to <12> It is an ink set as described in any one.
Condition (1): The viscosity at 25 ° C. is 100 mPa · s or less, or the viscosity at 60 ° C. is 30 mPa · s or less.
Condition (2): The boiling point is higher than 100 ° C.

<14> The ink set according to <13>, wherein the high-boiling organic solvent is contained in the first liquid.
<15> The ink set according to any one of <7> to <14>, wherein the colorant is a pigment.

<16> The ink set according to any one of <7> to <15>, wherein a water-insoluble liquid is used as the plurality of types of liquid solvents.
<17> The ink set according to any one of <7> to <16>, wherein the ink set is for inkjet recording.

<18> The ink set according to any one of <7> to <17>, which includes at least a first liquid and a second liquid, and includes a plurality of types of liquids. This is an inkjet image recording method in which an image is formed by applying a second liquid onto a recording medium at the same time, or applying one of them first and then the other.
<19> The inkjet image according to <18>, wherein the second liquid is ejected by an inkjet nozzle at the same time as or after the first liquid is applied on the recording medium. It is a recording method.

<20> The means for applying the first liquid onto the recording medium is application using a coating apparatus, and the second liquid is ejected by an inkjet nozzle after the first liquid is applied. The inkjet image recording method according to <18> or <19>.
<21> The inkjet according to any one of <18> to <20>, wherein the means for applying the first liquid and the second liquid onto the recording medium is ejection by an inkjet nozzle. Image recording method.

<22> The inkjet image recording method according to any one of <18> to <21>, wherein a step of applying energy to the image formed on the recording medium to fix the image is provided. It is.
<23> The inkjet image recording method according to <22>, wherein the energy is imparted by light irradiation or heating.

According to the present invention, while maintaining long-term storage stability and excellent fixing properties, it is possible to suppress blurring and changes in droplet ejection shape (thickening of the line width) that may occur when a time interval is left until exposure after printing. Thus, an ink set capable of forming a high-quality image and an ink composition used for the ink set can be provided.
In addition, according to the present invention, while maintaining excellent fixability, changes in droplet ejection shape (thickening of the line width) that can occur when there is a time interval between exposure and exposure after printing are suppressed, and stickiness is achieved. There can be provided an ink jet image recording method capable of forming a high-quality image excellent in scratch resistance.

  The ink composition of the present invention (hereinafter sometimes simply referred to as “ink composition”) is an ink composition comprising a compound having two or more carbamoyl groups and having a molecular weight of 1,000 or less. The ink composition is preferably used for ink jet recording, and preferably contains a polymerization initiator. Moreover, it is preferable to contain the high boiling point organic solvent mentioned later. Furthermore, you may contain various additives as needed.

  Further, the ink set of the present invention (hereinafter sometimes simply referred to as “ink set”) is preferably used for inkjet recording, and includes at least a first liquid and a second liquid, and includes a plurality of types. An ink set comprising a liquid, wherein the first liquid contains a compound having a molecular weight of 1000 or less and having two or more carbamoyl groups. In the ink set, the second liquid preferably contains a colorant, the first liquid contains a compound having a molecular weight of 1000 or less having two or more carbamoyl groups, and substantially contains the colorant. More preferably, the second liquid contains a colorant. By such a preferable aspect, it is possible to effectively suppress bleeding and droplet ejection interference, and it is possible to obtain an image without color separation.

  In the ink set of the present invention, from the viewpoint of obtaining excellent fixability, at least one of a plurality of types of liquids (including the first liquid and the second liquid) used in the image recording method is used. It is preferable that a polymerization initiator for curing the polymerizable compound is contained, and it is more preferable that the second liquid contains a polymerizable compound. The polymerization initiator is preferably contained in a liquid not containing a polymerizable compound (preferably the first liquid) from the viewpoint of storage stability of the liquid.

  In the present invention, if a low-boiling organic solvent (boiling point: 100 ° C. or lower) is included as the solvent used for the plurality of liquids, the curability may be affected, and if a water-soluble solvent is included, volatilization occurs. Since it takes time, and quick drying may not be obtained, it is preferable to constitute the liquid without using these solvents.

Furthermore, the inkjet image recording method of the present invention (hereinafter sometimes simply referred to as “image recording method”) uses a plurality of types of liquids including at least the first liquid and the second liquid, An inkjet image recording method for forming an image on a recording medium.
In the image recording method, at least one of the plurality of types of liquids contains a polymerizable compound, and the first liquid and the second liquid are simultaneously applied onto a recording medium, or one of them is the first. In addition, an image is formed by applying the other to the other.

Note that the application of the first liquid and the second liquid onto the recording medium is performed simultaneously with or after the application of the first liquid, and the second liquid is ejected by an inkjet nozzle. And more preferable from the viewpoint of suppression of droplet ejection interference and color separation.
Hereinafter, in describing the present invention in detail, the components constituting the ink composition or ink set of the present invention will be described first.

<Compound with a molecular weight of 1000 or less having two or more carbamoyl groups>
In the inkjet image recording method of the present invention, the first liquid contains a compound having a molecular weight of 1000 or less having substantially no colorant and two or more carbamoyl groups, while coloring the second liquid. It is preferable to contain an agent.
By applying the first liquid and the second liquid that satisfy the above conditions, bleeding and droplet ejection interference can be effectively suppressed, and an image without color separation can be obtained.

The compound having two or more carbamoyl groups and having a molecular weight of 1,000 or less (hereinafter sometimes referred to as “the compound according to the present invention”) is not particularly limited, but is preferably an alkylcarboxylic acid amide compound or an arylcarboxylic acid amide compound. Can be mentioned.
The carbamoyl group preferably has 2 to 32 carbon atoms, more preferably 4 to 20 carbon atoms, and particularly preferably 8 to 18 carbon atoms. Specific examples of the carbamoyl group include, for example, methylcarbamoyl group, ethylcarbamoyl group, n-propylcarbamoyl group, isopropylcarbamoyl group, n-butylcarbamoyl group, n-butylcarbamoyl group, s-butylcarbamoyl group, i-buty Examples thereof include a rucarbamoyl group, a t-butylcarbamoyl group, an n-amylcarbamoyl group, an isoamylcarbamoyl group, a phenylcarbamoyl group, an n-octylcarbamoyl group, a 2-ethylhexylcarbamoyl group, and a cyclohexylcarbamoyl group.
Of the compounds according to the present invention, a molecular weight of 800 or less is more preferred, and a molecular weight of 500 or less is particularly preferred.

  The compound having two or more carbamoyl groups and having a molecular weight of 1,000 or less is preferably a compound represented by the following general formula (1) or (2).

In general formula (1) and (2), R < ₁ > -R < ₈ > represents a hydrogen atom, an alkyl group, or an aryl group each independently. L ₁ represents an n + 1 valent linking group, L ₂ represents an m + 1 valent linking group, and m and n represent an integer of 1 or more.

In general formula (1) and (2), R < ₁ > -R < ₈ > represents a hydrogen atom, an alkyl group, or an aryl group each independently. These may have a substituent, and as the substituent of the alkyl group, an alkoxyl group, aryloxy group, halogen atom, arylamino group, amino group, carbamoyl group, hydroxyl group, acyloxy group, alkoxycarbonyl group, acylamino Group, etc., and aryl group, alkoxy group, and acyloxy group are preferable. Examples of the substituent of the aryl group include the alkyl group and the like in addition to the substituents exemplified in the substituent of the alkyl group, and among them, an alkyl group, an alkoxy group, and an acyloxy group are preferable.

The alkyl group represented by R _{1 to} R ₈ preferably has 1 to 32 carbon atoms, more preferably 2 to 24, and particularly preferably 4 to 18 carbon atoms. Specific examples of the alkyl group include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, t-butyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n -Decyl group, n-dodecyl group, octadecyl group, benzyl group, hydroxyethyl group, hydroxybutyl group, methoxyethyl group, ethoxyethyl group, 2-chloroethyl group, 3-chloropropyl group, acetoxyethyl group, acetoxybutyl group, Preferred examples include phenyloxyethyl group, phenyloxybutyl group, phenylethyloxyethyl group, and the like. N-butyl group, t-butyl group, n-hexyl group, n-octyl group, 2-ethylhexyl group, n-decyl And the group n-dodecyl is particularly preferred.

  The aryl group preferably has 6 to 32 carbon atoms, more preferably 6 to 24, and particularly preferably 6 to 18. Specific examples of the aryl group include phenyl group, naphthyl group, 2-methoxyphenyl group, 2-decyloxyphenyl group, 4-methoxyphenyl group, 2-octyloxynaphthyl group, dimethylaminophenyl group, 2-dodecylthiophenyl group. Group, 4- (4-methylphenylthioxy) phenyl group, 2-methoxy-4-dodecylthiooxyphenyl group, 2-phenoxyethoxyphenyl group, 2-dodecyloxyphenyl group, 2-octadecyloxyphenyl group, 2, 5-dibenzyloxyphenyl group, 2,5-dicyclohexylmethyloxyphenyl group, 2-methoxy-4- (2-ethylhexanoylamino) phenyl group, 2-butoxy-4-benzyloxycarbonylaminophenyl group, 2-octyloxy-4-butyloxycarbonylaminopheny Group, and the like.

The compound having two or more carbamoyl groups and having a molecular weight of 1,000 or less is at least _one of R ₁ and R ₄ in the general formula (1), or at least one of R ₆ and R ₇ in the general formula (2). Is more preferably a hydrogen atom.

  Specific examples of the compound having a molecular weight of 1,000 or less and having two or more carbamoyl groups include the following exemplified compounds: 1-1 to 1-22, and 2-1 to 2-7.

  The compound having two or more carbamoyl groups and having a molecular weight of 1,000 or less can be synthesized by a known synthesis method (see Experimental Chemistry Vol. 22, pages 137-173: edited by Chemical Society of Japan). For example, a method of condensing the carboxylic acid and the amine using a condensing agent (for example, dicyclohexylcarbodiimide), a method of causing the carboxylic acid halogen compound to act on the amine, a method of causing the amine to act on the acid anhydride, etc. Can be mentioned. In addition, carboxylic acids or their derivatives, amines, condensing agents and the like for synthesizing these compounds are generally available as reagents from, for example, Tokyo Chemical Industry Co., Ltd.

The compound having a molecular weight of 1,000 or less and having two or more carbamoyl groups is contained in at least the first liquid in the ink set, and further, other than the first liquid and the second liquid among the plurality of kinds of liquids. It may be contained in the liquid.
The amount of the compound having a molecular weight of 1000 or less having two or more carbamoyl groups is preferably 1% by mass to 90% by mass, more preferably 10% by mass to 75% by mass, and further preferably 20% by mass with respect to the entire ink composition. ˜50 mass% is particularly preferred. If the amount is less than this amount, the effect of the present invention cannot be exhibited sufficiently. If the amount is more than this amount, the viscosity becomes high.

<Polymerization initiator>
The ink composition of the present invention preferably contains a polymerization initiator.
In the ink set of the present invention, as described above, at least one of a plurality of types of liquids (including the first liquid and the second liquid) used is polymerized or crosslinked. It is preferable to contain the polymerization initiator hardened | cured by. Further, from the viewpoint of storage stability of the liquid, the polymerization initiator is more preferably contained in a liquid that does not substantially contain a polymerizable compound, and the polymerization is performed by applying energy to both on the recording medium. (Crosslinking) ・ Curing reaction occurs.

The polymerization initiator used in the present invention refers to a compound that generates an initiation species such as a radical by energy of light, heat, or both, and initiates and accelerates polymerization or crosslinking of the polymerizable compound. As the polymerization initiator in the present invention, a known thermal polymerization initiator, a compound having a bond with small bond dissociation energy, a photopolymerization initiator, or the like can be selected and used.
Examples of such radical generator include organic halogen compounds, carbonyl compounds, organic peroxide compounds, azo polymerization initiators, azide compounds, metallocene compounds, hexaarylbiimidazole compounds, organic boric acid compounds, disulfonic acid compounds, onium salts. Compounds and the like.

  Preferred examples of the polymerization initiator in the present invention include the following photopolymerization initiators. For example, light of acetophenone derivative, benzophenone derivative, benzyl derivative, benzoin derivative, benzoin ether derivative, benzyldialkyl ketal derivative, thioxanthone derivative, acylphosphine oxide derivative, metal complex, p-dialkylaminobenzoic acid, azo compound, peroxide compound, etc. Examples of the polymerization initiator include acetophenone derivatives, benzyl derivatives, benzoin ether derivatives, benzyl dialkyl ketal derivatives, thioxanthone derivatives, and acyl phosphine oxide derivatives, and acetophenone derivatives, benzoin ether derivatives, benzyl dialkyl ketal derivatives, acyl phosphine oxide derivatives. Is particularly preferred.

  Examples of specific compounds of such photopolymerization initiators include acetophenone, 2,2-diethoxyacetophenone, p-dimethylaminoacetophenone, p-dimethylaminopropiophenone, benzophenone, p, p′-dichloro. Benzophenone, p, p'-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin isopropyl ether, benzoin-n-propyl ether, benzoin isobutyl ether, benzyldimethyl ketal, 1-hydroxy-cyclohexyl phenyl ketone, tetramethyl Thiuram monosulfide, thioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,2-dimethylpropioyl diphenyl phosphite Oxide, 2-methyl-2-ethylhexanoyl diphenylphosphine oxide, 2,6-dimethylbenzoyldiphenylphosphine oxide, 2,6-dimethoxybenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, 2,3,6-trimethylbenzoyl-diphenylphosphine oxide, bis (2,3,6-trimethylbenzoyl) -phenyl Phosphine oxide, 2,4,6-trimethoxybenzoyl-diphenylphosphine oxide, 2,4,6-trichlorobenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzo Irnaphthyl phosphonate, bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -finyl) titanium, p-dimethylamino Examples include benzoic acid, p-diethylaminobenzoic acid, azobisisobutyronitrile, 1,1′-azobis (1-acetoxy-1-phenylethane), benzoin peroxide, and di-tert-butyl peroxide.

Examples of other preferable photopolymerization initiators include the photopolymerization initiators described on pages 65 to 148 of “UV Curing System” (published by General Technology Center Co., Ltd .: 1989) by Kiyosuke Kato. Can be mentioned.
As the polymerization initiator, those having excellent sensitivity are preferable. For example, those not causing thermal decomposition at a temperature of 80 ° C. or lower are preferable from the viewpoint of storage stability, and thermal decomposition is not caused at temperatures up to 80 ° C. It is preferable to select a polymerization initiator.
A polymerization initiator can be used 1 type or in combination of 2 or more types. Further, as long as the effects of the present invention are not impaired, a known sensitizer can be used in combination for the purpose of improving sensitivity.

  The polymerization initiator is preferably contained in a liquid different from the polymerizable compound described later, but the addition amount in the liquid is 0.5 to 20 masses from the viewpoints of stability over time, curability, and curing speed. % Is preferable, 1 to 15% by mass is more preferable, and 3 to 10% by mass is particularly preferable. When the content is too large, precipitation or separation with time may occur, or performance such as strength and rubbing resistance of the ink after curing may be deteriorated.

(High boiling point organic solvent)
The ink composition of the present invention can contain a high-boiling organic solvent that satisfies the following conditions (1) and (2).
Further, in the ink set of the present invention, a high boiling point organic solvent satisfying the following conditions (1) and (2) may be contained in any one or more of the plurality of liquids. Preferably, at least one of the first liquid or the second liquid contains a high-boiling organic solvent that satisfies the following conditions (1) and (2), and the first liquid has the following conditions: It is more preferable to contain a high boiling point organic solvent that satisfies the conditions (1) and (2).
Condition (1) The viscosity at 25 ° C. is 100 mPa · s or less, or the viscosity at 60 ° C. is 30 mPa · s or less.
Condition (2) The boiling point is higher than 100 ° C.

By containing the high-boiling organic solvent, it is possible to improve the effect of preventing bleeding and thickening of the line width, stickiness and scratch resistance.
In addition, from the viewpoint of further suppressing the occurrence of bleeding and thickening of the line width, the high boiling point organic solvent is more preferably contained in a liquid not containing a polymerizable compound.

  A high boiling point organic solvent having a viscosity at 25 ° C. of more than 100 mPa · s or a viscosity at 60 ° C. of more than 30 mPa · s may increase the viscosity and hinder the application of the liquid onto the recording medium. On the other hand, in the case of a high boiling point organic solvent having a boiling point of 100 ° C. or lower, the boiling point becomes too low and it may evaporate during image formation, and the effect of avoiding bleeding and line width increase according to the present invention may not be obtained. From the environmental aspect, it is desirable that the organic solvent evaporate and not be released into the atmosphere.

  Of the conditions (1), the viscosity at 25 ° C. is preferably 70 mPa · s or less, more preferably 40 mPa · s or less, and particularly preferably 20 mPa · s or less. . The viscosity at 60 ° C. is further preferably 20 mPa · s or less, and particularly preferably 10 mPa · s or less. Moreover, the boiling point which is the condition of (2) is more preferably 150 ° C or higher, and particularly preferably 170 ° C or higher. Furthermore, the high-boiling organic solvent preferably has a melting point of 80 ° C. or less, and preferably has a water solubility (25 ° C.) of 4 g or less. The solubility of water is further preferably 3 g or less, more preferably 2 g or less, and particularly preferably 1 g or less.

Here, “viscosity” in the present invention refers to the viscosity determined by the following means.
The viscosity is a value measured using a RE80 viscometer manufactured by Toki Sangyo Co., Ltd. The RE80 type viscometer is a conical rotor / flat plate type viscometer corresponding to the E type. The number of revolutions is measured at 10 rpm using one rotor. However, for those having a viscosity higher than 60 mPa · s, the rotational speed is appropriately changed to 5, 2.5, 1, 0.5 and measured.
In the present invention, “water solubility” is the saturation concentration of water in a high-boiling organic solvent at 25 ° C., and means the mass (g) of water that can be dissolved in 100 g of the high-boiling organic solvent at 25 ° C. .

  In the ink set of the present invention, the amount of the high-boiling organic solvent used is preferably 5 to 2000% by mass, more preferably 10 to 1000% by mass in terms of the coating amount, based on the colorant to be used.

  In the present invention, the high-boiling organic solvent is preferably a compound represented by the following formulas [S-1] to [S-9].

In the formula [S-1], R ₁₁ , R ₁₂ and R ₁₃ each independently represents an aliphatic group or an aryl group. A, b and c each independently represent 0 or 1;
In the formula [S-2], R ₁₄ and R ₁₅ each independently represents an aliphatic group or an aryl group, and R ₁₆ represents a halogen atom (F, Cl, Br, I and the same shall apply hereinafter), an alkyl group, an alkoxy group. Represents an aryloxy group, an alkoxycarbonyl group or an aryloxycarbonyl group, and d represents an integer of 0 to 3. When d is plural, plural R ₁₆ may be the same or different.

In the formula [S-3], Ar represents an aryl group, e represents an integer of 1 to 6, and R ₁₇ represents an e-valent hydrocarbon group or a hydrocarbon group bonded to each other through an ether bond.
In the formula [S-4], R ₁₈ represents an aliphatic group, f represents an integer of 1 to 6, and R ₁₉ represents a hydrocarbon group bonded to each other by an f-valent hydrocarbon group or an ether bond.

In the formula [S-5], g represents an integer of 2 to 6, R ₂₀ represents a g-valent hydrocarbon group (excluding an aryl group), and R ₂₁ represents an aliphatic group or an aryl group.
In the formula [S-6], R ₂₂ , R ₂₃ and R ₂₄ each independently represents a hydrogen atom, an aliphatic group or an aryl group. X represents —CO— or —SO ₂ —. R ₂₂ and R ₂₃ or R ₂₃ and R ₂₄ may be bonded to each other to form a ring.

In the formula [S-7], R ₂₅ represents an aliphatic group, an alkoxycarbonyl group, an aryloxycarbonyl group, an alkylsulfonyl group, an arylsulfonyl group, an aryl group or a cyano group, R ₂₆ represents a halogen atom, an aliphatic group, An aryl group, an alkoxy group or an aryloxy group is represented, and h represents an integer of 0 to 3. When h is plural, plural R ₂₆ may be the same or different.

In the formula [S-8], R ₂₇ and R ₂₈ each independently represents an aliphatic group or an aryl group, R ₂₉ represents a halogen atom, an aliphatic group, an aryl group, an alkoxy group or an aryloxy group, i represents an integer of 0 to 4. When i is plural, the plural R ₂₉ may be the same or different.
In the formula [S-9], R ₃₀ and R ₃₁ each independently represents an aliphatic group or an aryl group. j represents 1 or 2; R ₃₀ and R ₃₁ may be bonded to each other to form a ring.

In the above formulas [S-1] to [S-9], when R _{11 to} R ₁₆ , R ₁₈ and R _{21 to} R ₃₁ are an aliphatic group or a group containing an aliphatic group, the aliphatic group is linear. These may be branched or cyclic, and may contain an unsaturated bond or may have a substituent. Examples of the substituent include a halogen atom, an aryl group, an alkoxy group, an aryloxy group, an alkoxycarbonyl group, a hydroxyl group, an acyloxy group, and an epoxy group.

In the above formulas [S-1] to [S-9], R _{11 to} R ₁₆ , R ₁₈ and R _{21 to} R ₃₁ are cyclic aliphatic groups, that is, cycloalkyl groups, or groups containing cycloalkyl groups. In some cases, the cycloalkyl group may contain an unsaturated bond in the 3- to 8-membered ring, and may have a substituent or a bridging group. Examples of the substituent include a halogen atom, an aliphatic group, a hydroxyl group, an acyl group, an aryl group, an alkoxy group, an epoxy group, and an alkyl group, and examples of the cross-linking group include methylene, ethylene, isopropylidene, and the like.

In the above formulas [S-1] to [S-9], when R _{11 to} R ₁₆ , R ₁₈ , R _{21 to} R ₃₁ , Ar is an aryl group or a group containing an aryl group, the aryl group is a halogen atom, an aliphatic group It may be substituted with a substituent such as a group, an aryl group, an alkoxy group, an aryloxy group or an alkoxycarbonyl group.

In the above formulas [S-3], [S-4], and [S-5], when R ₁₇ , R _19, or R ₂₀ is a hydrocarbon group, the hydrocarbon group is a cyclic structure (for example, a benzene ring or a cyclopentane ring). , A cyclohexane ring) or an unsaturated bond, and may have a substituent. Examples of the substituent include a halogen atom, a hydroxyl group, an acyloxy group, an aryl group, an alkoxy group, an aryloxy group, and an epoxy group.

Hereinafter, among the high boiling point organic solvents represented by the formulas [S-1] to [S-9], particularly preferred high boiling point organic solvents will be described.
In the formula [S-1], R ₁₁ , R ₁₂ and R ₁₃ are each independently an aliphatic group having 1 to 24 (preferably 4 to 18) carbon atoms (for example, n-butyl, n-hexyl, n-octyl, EH-octyl, 2-ethylhexyl, 3,3,5-trimethylhexyl, 3,5,5-trimethylhexyl, n-dodecyl, n-octadecyl, benzyl, oleyl, 2-chloroethyl, 2,3- Dichloropropyl, 2-butoxyethyl, 2-phenoxyethyl, cyclopentyl, cyclohexyl, 4-t-butylcyclohexyl, 4-methylcyclohexyl), or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (For example, phenyl, cresyl, p-nonylphenyl, xylyl, cumenyl, p-methoxyphenyl, p-methoxycarbonylpheny Each group) is preferred. Among these, R ₁₁ , R ₁₂ and R ₁₃ are particularly n-hexyl, n-octyl, EH-octyl, 2-ethylhexyl, 3,5,5-trimethylhexyl, n-dodecyl, 2-chloroethyl, 2- More preferred are butoxyethyl, cyclohexyl, phenyl, cresyl, p-nonylphenyl, and cumenyl groups.
a, b, and c are each independently 0 or 1, and more preferably, all of a, b, and c are 1.

In the formula [S-2], R ₁₄ and R ₁₅ are each independently an aliphatic group having 1 to 24 (preferably 4 to 18) carbon atoms (for example, the same as the aliphatic groups mentioned for R ₁ above). Group, heptyl, ethoxycarbonylmethyl, 1,1-diethylpropyl, 2-ethyl-1-methylhexyl, cyclohexylmethyl, 1-ethyl-1,5-dimethylhexyl, 3,5,5-trimethylcyclohexyl, menthyl, bornyl , 1-methylcyclohexyl group), or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, the aryl group mentioned for R ₁₁ , 4-t-butylphenyl, 4-t-octyl). Phenyl, 1,3,5-trimethylphenyl, 2,4, -di-t-butylphenyl, 2,4, -di-t-pentylphenyl). Among these, R ₁₄ and R ₁₅ are more preferably aliphatic groups, and more preferably n-butyl, heptyl, 2-ethylhexyl, n-dodecyl, 2-butoxyethyl, and ethoxycarbonylmethyl groups.

R ₁₆ is a halogen atom (preferably a chlorine atom), an alkyl group having 1 to 18 carbon atoms (for example, methyl, isopropyl, t-butyl, or n-dodecyl group), an alkoxy group having 1 to 18 carbon atoms (for example, Methoxy, n-butoxy, n-octyloxy, methoxyethoxy, benzyloxy groups), aryloxy groups having 6 to 18 carbon atoms (for example, phenoxy, p-tolyloxy, 4-methoxyphenoxy, 4-t-butylphenoxy) Each group), an alkoxycarbonyl group having 2 to 19 carbon atoms (for example, each group of methoxycarbonyl, n-butoxycarbonyl, 2-ethylhexyloxycarbonyl) or an aryloxycarbonyl group having 6 to 25 carbon atoms. Among these, R ₁₆ is further preferably an alkoxycarbonyl group, and more preferably an n-butoxycarbonyl group.
d is preferably 0 or 1.

In the formula [S-3], Ar represents an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, phenyl, 4-chlorophenyl, 2,4-dichlorophenyl, 4-methoxyphenyl, 1-naphthyl, 4 -N-butoxyphenyl, 1,3,5-trimethylphenyl, 2- (2-n-butoxycarbonylphenyl) phenyl), and among these, Ar is phenyl, 2,4-dichlorophenyl, 2- ( 2-n-butoxycarbonylphenyl) phenyl is more preferred.
e is preferably an integer of 1 to 4 (preferably 1 to 3).

R ₁₇ is e-valent hydrocarbon group [for example the aliphatic group exemplified for R ₁₄ carbon atoms 2 to 24 (preferably 2 to 18), n-octyl group, an aryl group as listed for the above-described R _14, - (CH ₂ ) ₂ −,

Or an e-valent hydrocarbon group having 4 to 24 (preferably 4 to 18) carbon atoms bonded to each other via an ether bond [for example, —CH ₂ CH ₂ OCH ₂ CH ₂ —, —CH ₂ CH ₂ (OCH ₂ CH _{2) 3 -, - CH 2} CH 2 CH 2 OCH 2 CH 2 CH 2 -,

Is preferred. Among these, R ₁₇ is more preferably an alkyl group, and particularly preferably n-butyl, n-octyl, and 2-ethylhexyl groups.

In the above formula [S-4], R ₁₈ is an aliphatic group having 1 to 24 (preferably 1 to 17) carbon atoms (for example, methyl, n-propyl, 1-hydroxyethyl, 1-ethylpentyl, n-heptyl, n-undecyl, n-tridecyl, pentadecyl, 8,9-epoxyheptadecyl, cyclopropyl, cyclohexyl and 4-methylcyclohexyl groups) are preferred. Among these, R ₁₈ is particularly n-heptyl, n-tridecyl. , 1-hydroxyethyl, 1-ethylpentyl, and 8,9-epoxyheptadecyl are preferable.
f is preferably an integer of 1 to 4 (preferably 1 to 3).

R ₁₉ is a hydrocarbon group having 2 to 24 (preferably 2 to 18) f-valent carbon atoms or a hydrocarbon group linked to each other by an ether bond having 4 to 24 (preferably 4 to 18) f-valent carbon atoms. (For example, the groups listed for R ₁₇ , 1-methyl-2-methoxyethyl, 2-hexyldecyl) are preferable, and among these, R ₁₉ is particularly 2-ethylhexyl, 2-hexyldecyl, 1- Methyl-2-methoxyethyl,

Is preferred.
In the formula [S-5], g is preferably 2 to 4, more preferably 2 or 3.
R ₂₀ represents a g-valent hydrocarbon group [for example, —CH ₂ —, — (CH ₂ ) ₂ —, — (CH ₂ ) ₄ —, — (CH ₂ ) ₇ —, — (CH ₂ ) ₈ —,

Among these, R ₂₀ is particularly — (CH ₂ ) ₄ —, — (CH ₂ ) ₈ —,

Is preferred.
R ₂₁ is an aliphatic group having 1 to 24 carbon atoms (preferably 4 to 18), or an aryl group having 6 to 24 carbon atoms (preferably 6 to 18 carbon atoms) (for example, the aliphatic groups mentioned above for R ₁₄ ; Aryl group), and among these, R ₂₁ is more preferably an alkyl group, and in particular, n-butyl, n-octyl and 2-ethylhexyl groups are preferred.

In the formula [S-6], R ₂₂ represents a hydrogen atom, an aliphatic group having 1 to 24 carbon atoms (preferably 3 to 20) [for example, n-propyl, 1-ethylpentyl, n-undecyl, n-pentadecyl. 2,4-di-t-pentylphenoxymethyl, 4-t-octylphenoxymethyl, 3- (2,4-di-t-butylphenoxy) propyl, 1- (2,4-di-t-butylphenoxy) Propyl, cyclohexyl, 4-methylcyclohexyl, each group of 8-N, N-diethylcarbamoyloctyl], or an aryl group having 6 to 24 (preferably 6 to 18) carbon atoms (for example, the aryl group mentioned for Ar, 3-methylphenyl, 2-(N, N-di -n- octylcarbamoyl) each group) are preferred phenyl, among these, R ₁₂ is especially, n- undecyl 8-N, N-diethylcarbamoyl-octyl, 3-methylphenyl, 2-(N, N-di -n- octylcarbamoyl) each group of phenyl preferred.

R ₂₃ and R ₂₄ are each a hydrogen atom, an aliphatic group having 1 to 24 carbon atoms (preferably 1 to 18 carbon atoms) (for example, methyl, ethyl, isopropyl, n-butyl, n-hexyl, n-octyl, 2-ethylhexyl). , N-dodecyl, n-tetradecyl, cyclopentyl, and cyclopropyl groups) or an aryl group having 6 to 18 carbon atoms (preferably 6 to 15) (for example, phenyl, 1-naphthyl, and p-tolyl groups). Among these, R ₂₃ and R ₂₄ are particularly preferably methyl, ethyl, n-butyl, n-octyl, n-tetradecyl, and phenyl groups.

R ₂₃ and R ₂₄ may be bonded to each other to form a pyrrolidine ring, piperidine ring or morpholine ring together with the nitrogen atom, and R ₂₂ and R ₂₃ may be bonded to each other to form a pyrrolidone ring or piperidine ring together with the nitrogen atom. May be.
X is —CO— or —SO ₂ —, and preferably X is —CO—.

In the formula [S-7], R ₂₅ represents an aliphatic group having 1 to 24 (preferably 3 to 18) carbon atoms (for example, methyl, isopropyl, t-butyl, t-pentyl, t-hexyl, t-octyl, 2 -Butyl, 2-hexyl, 2-octyl, 2-dodecyl, 2-hexadecyl, t-pentadecyl, cyclopentyl, and cyclohexyl groups), an alkoxycarbonyl group having 2 to 24 carbon atoms (preferably 5 to 17 carbon atoms) (for example, n-butoxycarbonyl, 2-ethylhexyloxycarbonyl, n-dodecyloxycarbonyl groups), aryloxycarbonyl groups having 7 to 24 carbon atoms (preferably 7 to 18) (for example, phenoxycarbonyl, naphthoxycarbonyl, Each group of diloxycarbonyl), alkyl having 1 to 24 (preferably 1 to 18) carbon atoms A sulfonyl group (for example, each group of methylsulfonyl, n-butylsulfonyl, n-dodecylsulfonyl), an arylsulfonyl group having 6 to 30 carbon atoms (preferably 6 to 24) (for example, p-tolylsulfonyl, p-dodecylphenylsulfonyl) , Each group of p-hexadecyloxyphenylsulfonyl), an aryl group having 6 to 32 carbon atoms (preferably 6 to 24 carbon atoms) (for example, each group of phenyl and p-tolyl), 3 to 18 carbon atoms (more preferably 5 to 17) cycloalkyl group (for example, each group of cyclopentyl and cyclohexyl), aryl group having 6 to 32 carbon atoms (preferably 6 to 24 carbon atoms) (for example, each group of phenyl and p-tolyl) 1 carbon atom To 24 (preferably 1 to 18) alkoxy groups (eg methoxy, n-butoxy, 2-ethylhexyloxy, Benzyloxy, n-dodecyloxy, n-hexadecyloxy) or aryloxy groups having 6 to 32 (preferably 6 to 24) carbon atoms (for example, phenoxy, pt-butylphenoxy, pt-octyl) Each group of phenoxy, m-pentadecylphenoxy, p-dodecyloxyphenoxy) or a cyano group is preferable, and among these, R ₂₅ is more preferably an aliphatic group, and in particular, t-butyl, hexyl, octyl, and nonyl. Each group is preferred.

In the formula [S-8], R ₂₇ and R ₂₈ are the same as the examples other than the hydrogen atom in R ₂₃ and R ₂₄ , and among these, R ₂₇ and R ₂₈ are more preferably an aliphatic group, In particular, n-butyl, n-octyl, and n-dodecyl are preferable. However, R ₂₇ and R ₂₈ are not bonded to each other to form a ring.

R ₂₉ is the same as R ₂₆ described above. Among them, R ₂₉ is more preferably an alkyl group or an alkoxy group, and particularly preferably n-octyl, methoxy, n-butoxy and n-octyloxy groups.
i is preferably an integer of 1 to 3.

In the formula [S-9], R ₃₀ and R ₃₁ are the same as R ₁₁ , R ₁₂ and R ₁₃ when they are not bonded to form a ring. Among these, R ₃₀ and R ₃₁ are In particular, methyl, ethyl, butyl, hexyl and octyl groups are preferred.
R ₃₀ and R ₃₁ may be bonded to each other to form a ring, and the formed ring is preferably a 5-membered ring or a 6-membered ring.
j represents 1 or 2, and preferably j is 1.

  Specific examples (exemplary compounds: S-1 to 53) of the high boiling point organic solvent used in the present invention are shown below.

  In the present invention, the high-boiling organic solvent may be used alone or in combination of two or more [for example, tricresyl phosphate and dibutyl phthalate, trioctyl phosphate and di (2-ethylhexyl) sebacate, dibutyl phthalate and poly (Nt-butylacrylamide)] may be used.

  In the ink set of the present invention, the mass ratio of the colorant to the high-boiling organic solvent is preferably 1: 0.01 to 1: 1, and 1: 0. More preferably, it is 0.05 to 1: 0.5.

  Examples of other high boiling point organic solvents used in the present invention and / or methods for synthesizing these high boiling point organic solvents include, for example, U.S. Pat. Nos. 2,322,027 and 2,533,514. 2,772,163, 2,835,579, 3,594,171, 3,676,137, 3,689,271, 3, 700,454, 3,748,141, 3,764,336, 3,765,897, 3,912,515, 3,936,303, 4,004,928, 4,080,209, 4,127,413, 4,193,802, 4,207,393, 4,220 No.711, No.4,239,851, No.4,278,75 No. 4,353,979, No. 4,363,873, No. 4,430,421, No. 4,430,422, No. 4,464,464, No. 4 No. 4,483,918, No. 4,540,657, No. 4,684,606, No. 4,728,599, No. 4,745,049, No. 4,935,321. 5,013,639, European Patent Nos. 276,319A, 286,253A, 289,820A, 309,158A, 309,159A, 309, No. 160A, No. 509,311A, No. 510,576A, East German Patent Nos. 147,009, No. 157,147, No. 159,573, No. 225,240A, British Patent No. 2 , 091,124A, etc. 47335, 50-26530, 51-25133, 51-26036, 51-27921, 51-27922, 51-149028, 52-46816, 53-1520 53-1521, 53-15127, 53-146622, 54-91325, 54-106228, 54-118246, 55-59464, 56-64333, 56-81836, 59-204041, 61-84441, 62-118345, 62-247364, 63-167357, 63-214744, 63-301941, 64 -9452, 64-9454, 64-68745, JP-A-1-101543, 1-102454 No. 2-792, No. 2-4239, No. 2-43541, No. 4-29237, No. 4-30165, No. 4-232946, No. 4-346338, etc. ing.

<Colorant>
The ink set of the present invention preferably contains a colorant in at least one ink (liquid).
In addition, in the ink set of the present invention, as described above, the first liquid contains a compound having a molecular weight of 1000 or less and substantially containing no colorant and having two or more carbamoyl groups. The liquid preferably contains a colorant.

  The fact that the first liquid does not substantially contain a colorant does not exclude the inclusion of colorless and transparent dyes / pigments, and a very small amount that cannot be visually recognized. It may be 0.5 or less, preferably 0.1 or less, and particularly preferably 0.01 or less, in terms of the solution absorbance at the maximum absorption wavelength in the visible light region that has passed through the ink solution.

Here, the absorbance is a value represented by the following expression, where I0 and I are the light intensities before and after the sample incidence, respectively.
Absorbance = −log (I0 / I)
Since the absorbance varies depending on the cell length of the measurement solution, in the present text, the absorbance in a solution having a thickness of 1 cm is used as the value.

  Further, the colorant can be contained in another liquid other than the first liquid and the second liquid. However, from the viewpoint of suppression of bleeding and droplet ejection interference, the other liquid containing the colorant and the second liquid preferably do not substantially contain a compound having a molecular weight of 1000 or less and having two or more carbamoyl groups. The content is substantially 0 to 10% by mass, more preferably 0 to 5% by mass, and particularly preferably 0 to 1% by mass. .

  The colorant used in the present invention is not particularly limited, and can be appropriately selected from known water-soluble dyes, oil-soluble dyes and pigments as long as they can achieve a hue and color density suitable for the intended use of the ink. be able to. Among these, the liquid constituting the ink set of the present invention is preferably a water-insoluble liquid and does not contain an aqueous solvent from the viewpoint of ink droplet stability and quick-drying. It is preferable to use an oil-soluble dye or pigment that is easily dispersed and dissolved in a water-soluble liquid.

(Oil-soluble dye)
There is no restriction | limiting in particular in the oil-soluble dye which can be used for this invention, Arbitrary things can be used. Hereinafter, oil-soluble dyes that can be used in the present invention are exemplified for each hue.
Examples of yellow dyes include phenols, naphthols, anilines, pyrazolones, pyridones, aryl or heteryl azo dyes having open-chain active methylene compounds as coupling components; open-chain active methylene compounds as coupling components. Azomethine dyes; methine dyes such as benzylidene dyes and monomethine oxonol dyes; quinone dyes such as naphthoquinone dyes and anthraquinone dyes, and the like. Other dye species include quinophthalone dyes, nitro / nitroso dyes, Examples include acridine dyes and acridinone dyes.

  Examples of magenta dyes include aryl or heteryl azo dyes having phenols, naphthols, and anilines as coupling components; azomethine dyes having pyrazolones and pyrazolotriazoles as coupling components; arylidene dyes, styryl dyes, and merocyanine dyes Methine dyes such as oxonol dyes; carbonium dyes such as diphenylmethane dyes, triphenylmethane dyes, xanthene dyes, quinone dyes such as naphthoquinone, anthraquinone and anthrapyridone, condensed polycyclic dyes such as dioxazine dyes Etc.

  Examples of cyan dyes include indoaniline dyes, indophenol dyes, or azomethine dyes having pyrrolotriazoles as coupling components; polymethine dyes such as cyanine dyes, oxonol dyes, and merocyanine dyes; diphenylmethane dyes, triphenylmethane dyes, xanthenes Examples thereof include carbonium dyes such as dyes; phthalocyanine dyes; anthraquinone dyes; aryl or heteryl azo dyes having phenols, naphthols and anilines as coupling components, and indigo / thioindigo dyes.

  Each of the above-mentioned dyes may exhibit yellow, magenta, and cyan colors only after a part of the chromophore group is dissociated. In this case, the counter cation may be an alkali metal or ammonium. It may be an inorganic cation, may be an organic cation such as pyridinium or quaternary ammonium salt, and may further be a polymer cation having them in a partial structure.

  In the ink set of the present invention, the content of the dye when an oil-soluble dye is used as the colorant is preferably in the range of 0.05 to 20% by mass in terms of solid content in the second liquid. 0.1 to 15% by mass is more preferable, and 0.2 to 6% by mass is particularly preferable. Moreover, as content in the case where it contains in another liquid other than a 1st liquid and a 2nd liquid, the range of 0-1 mass% in conversion of solid content in this liquid is preferable.

(Pigment)
An embodiment in which a pigment is used as the colorant is also preferable from the viewpoint that aggregation easily occurs when a plurality of liquids are mixed.
As the pigment used in the present invention, either an organic pigment or an inorganic pigment can be used, and as the black pigment, a carbon black pigment or the like is preferably exemplified. In general, pigments of three primary colors of black and cyan, magenta, and yellow are used, but pigments having other hues such as red, green, blue, brown, white, gold, silver, etc. The metallic luster pigment, colorless or light-colored extender pigment, and the like can also be used depending on the purpose.

In addition, particles having silica, alumina, resin, or the like as a core material and having a dye or pigment fixed on the surface, an insoluble raked product of a dye, a colored emulsion, a colored latex, or the like can also be used as a pigment.
Furthermore, resin-coated pigments can also be used. This is called a microcapsule pigment, and is also available as a commercial product from Dainippon Ink and Chemicals, Toyo Ink, etc.

  The volume average particle diameter of the pigment particles contained in the liquid in the present invention is preferably in the range of 10 to 250 nm, more preferably 50 to 200 nm, from the viewpoint of the balance between optical density and storage stability. . Here, the volume average particle diameter of the pigment particles can be measured by a measuring device such as LB-500 (manufactured by HORIBA).

The content in the case of using a pigment as the colorant is preferably in the range of 0.1% by mass to 20% by mass in terms of solid content in the second liquid, from the viewpoint of optical density and jet stability. More preferably, it is in the range of 1% by mass to 10% by mass. Moreover, as content in the case where it contains in another liquid other than a 1st liquid and a 2nd liquid, the range of 0-1 mass% in conversion of solid content in this liquid is preferable.
The colorant may be used alone or in combination of two or more. Further, different colorants may be used for each liquid, or the same may be used.

<Polymerizable compound>
The ink composition of the present invention preferably contains a polymerizable compound.
In the ink set of the present invention, it is preferable that at least one of a plurality of types of liquids including the first liquid and the second liquid contains a polymerizable compound, and the second liquid is polymerizable. It is more preferable to contain a compound. The polymerizable compound has a function of causing a polymerization reaction or a crosslinking reaction and curing by an initiating species such as a radical generated from the polymerization initiator.

  As the polymerizable compound, known polymerizable compounds such as a radical polymerization reaction, a cationic polymerization reaction, and a dimerization reaction can be applied. Addition polymerizable compound having at least one ethylenically unsaturated double bond, epoxy compound, oxetane compound, oxirane compound, polymer compound having maleimide group in side chain, photodimerization adjacent to aromatic nucleus is possible Cinnamyl group having an unsaturated double bond, a polymer compound having a cinnamylidene group or a chalcone group in the side chain, and the like, more preferably an addition polymerizable compound having at least one ethylenically unsaturated double bond, It is particularly preferable that the compound is selected from compounds having at least one ethylenically unsaturated bond, more preferably two or more (monofunctional or polyfunctional compound). Specifically, it can be appropriately selected from those widely known in the industrial field according to the present invention, for example, monomers, prepolymers, that is, dimers, trimers and oligomers, or mixtures thereof, and Those having a chemical form such as a copolymer of

  The polymerizable compound preferably has a polymerizable group such as an acryloyl group, a methacryloyl group, an allyl group, a vinyl group, or an internal double bond group (such as maleic acid) in the molecule, and among them, an acryloyl group or a methacryloyl group. A compound having a group is preferable because a curing reaction can be caused with low energy.

As the polyfunctional polymerizable compound that can be used in the present invention, a vinyl group-containing aromatic compound, a (meth) acrylate that is an ester of a divalent or higher alcohol and (meth) acrylic acid, a divalent or higher amine, and a ) (Meth) acrylamide, which is an amide with acrylic acid, polyester (meth) acrylate in which (meth) acrylic acid is introduced into ester or polycaprolactone obtained by combining polybasic acid and dihydric alcohol, alkylene oxide and polyhydric alcohol It is obtained by introducing (meth) acrylic acid into the ether obtained by bonding of (meth) acrylic acid into the ether obtained by introducing the (meth) acrylic acid into the epoxy resin, or by reacting a divalent or higher alcohol with an epoxy-containing monomer. Epoxy (meth) acrylate, urethane acrylate with urethane bond Amino resin acrylate, acrylic resin acrylate, alkyd resin acrylate, spirane resin acrylate, silicone resin acrylate, reaction product of unsaturated polyester and photopolymerizable monomer, and reaction product of waxes and polymerizable monomer (Meth) acrylate, polyester (meth) acrylate, polyether (meth) acrylate, epoxy acrylate, urethane acrylate, acrylic resin acrylate, silicone resin acrylate, reaction product of unsaturated polyester and the photopolymerizable monomer is preferred, Particularly preferred are acrylates, polyester acrylates, polyether acrylates, epoxy acrylates and urethane acrylates.
In this specification, when referring to either or both of acrylic acid and methacrylic acid, “(meth) acrylic acid” may be used.

  Specific examples of the polyfunctional polymerizable compound include, for example, divinylbenzene, 1,3-butanediol diacrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, trimethylolpropane triacrylate, and dipentaerythritol hexaacrylate. 1,6-acryloylaminohexane, hydroxypivalate ester neopentylglycol diacrylate, polyester acrylate having a (meth) acryloyl group at the molecular chain end of a polyester having a molecular weight of 500 to 30,000 consisting of a dibasic acid and a dihydric alcohol, polyethylene Glycol diacrylate, epoxy acrylate containing bisphenol (A or S, F) skeleton having a molecular weight of 450 to 30,000, skeleton of phenol novolac resin Epoxy acrylate with a molecular weight of 600 to 30,000 with the reaction of a polyvalent isocyanate and a hydroxyl group (meth) acrylate monomer having a molecular weight of 350 to 30,000, also urethane-modified product having a urethane bond in the molecule.

  Examples of the monofunctional polymerizable monomer that can be used in the present invention include (meth) acrylate, styrene, acrylamide, vinyl group-containing monomers (vinyl esters, vinyl ethers, N-vinyl amide, etc.), (meth) acrylic acid, and the like. (Meth) acrylate, acrylamide, vinyl esters and vinyl ethers are preferable, and (meth) acrylate and acrylamide are particularly preferable. These polymerizable monomers may have a substituent, and examples of the substituent that can be introduced include a halogen atom, a hydroxyl group, an amide group, and a carboxylic acid group.

  Specific examples of the monofunctional polymerizable monomer include, for example, hydroxyethyl acrylate, glycidyl acrylate, tetrahydrofurfuryl acrylate, dicyclopentenyl acrylate, 2-acryloyloxyethyl phosphate, allyl acrylate, N, N-dimethylaminoethyl acrylate. N, N-dimethylacrylamide, N, N-diethylaminopropylacrylamide, N-butoxymethylacrylamide, acryloylmorpholine, 2-hydroxyethyl vinyl ether, N-vinylformamide, N-vinylacetamide, 2-cyclohexylcarbamoyloxyethyl acrylate, ester Acrylate containing polybutyl acrylate moiety in the ester and acrylate containing polydimethylsiloxane moiety in the ester Such as theft and the like.

Only 1 type may be used for a polymeric compound and it may use it in combination of 2 or more type.
The content of the polymerizable compound contained in any one or more of the plurality of types of liquids is preferably in the range of 20 to 98% by mass in terms of solid content in all liquids, and is 40 to 95% by mass. The range is more preferable, and the range of 50 to 90% by mass is further preferable.

<Ink set>
The ink set of the present invention includes at least the first liquid (ink) and the second liquid (ink) described above, and includes a plurality of types of liquids. The plurality of types of liquids according to the present invention contain virtually no colorant and contain the first liquid containing the compound (a) according to the present invention and the colorant (b). It is preferable to use a plurality of kinds of liquids including at least the second liquid, and to contain the polymerizable compound (c) in at least one of the plurality of kinds of liquids.
Here, a two-liquid type consisting of a first liquid and a second liquid will be described as an example.
(1) A combination in which the compound (a) and the polymerizable compound (c) according to the present invention are contained in the first liquid, and the colorant (b) is contained in the second liquid,
(2) A combination in which the compound (a) according to the present invention is contained in the first liquid, and the colorant (b) and the polymerizable compound (c) are contained in the second liquid,
(3) A combination in which the compound (a) and the polymerizable compound (c) according to the present invention are contained in the first liquid, and the colorant (b) and the polymerizable compound (c) are contained in the second liquid,
Is mentioned.

In each of the above (1) to (3), the first liquid and / or the second liquid preferably further contains a polymerization initiator, but from the viewpoint of storage stability, (1) or ( In the aspect of 2), it is more preferable that the polymerizable compound (c) is contained in a liquid that does not contain the polymerizable compound (c).
When using three or more liquids, the first and / or second liquid may contain a polymerization initiator, and the first and / or second liquid does not contain a polymerization initiator. You may contain in a 3rd liquid. Alternatively, the polymerization initiator may be contained in the first and / or second liquid and contained in the third liquid.
By applying the first liquid and the second liquid that satisfy the above conditions, it is possible to effectively suppress bleeding and thickening of the line width, and an image having excellent stickiness and scratch resistance can be obtained.

<Other ingredients>
In addition to the components described above, the following additives can be used in combination with the ink composition of the present invention or the plurality of liquids in the ink set of the present invention in accordance with the purpose.
(Storage stabilizer)
In the present invention, a storage stabilizer can be added for the purpose of suppressing undesirable polymerization during storage of a plurality of types of liquids. The storage stabilizer is preferably used in the same liquid as the polymerizable compound, and it is preferable to use a storage stabilizer that is soluble in the liquid or other coexisting components.

  Storage stabilizers include quaternary ammonium salts, hydroxyamines, cyclic amides, nitriles, substituted ureas, heterocyclic compounds, organic acids, hydroquinones, hydroquinone monoethers, organic phosphines, copper compounds, and the like. Specific examples include benzyltrimethylammonium chloride, diethylhydroxylamine, benzothiazole, 4-amino-2,2,6,6-tetramethylpiperidine, citric acid, hydroquinone monomethyl ether, hydroquinone monobutyl ether, and copper naphthenate. It is done.

  The addition amount of the storage stabilizer is preferably adjusted as appropriate based on the activity of the polymerization initiator used, the polymerizability of the polymerizable compound, and the type of the storage stabilizer. However, the storage stability and the curability of the ink during liquid mixing are preferred. From the standpoint of balance, the amount is preferably 0.005 to 1% by mass in terms of solid content in the liquid, more preferably 0.01 to 0.5% by mass, and still more preferably 0.01 to 0.2% by mass. .

(Conductive salts)
Conductive salts are solid compounds that improve conductivity. In the present invention, it is preferable not to use it substantially because there is a great concern of precipitation during storage, but it is possible to increase the solubility of conductive salts or use a highly soluble liquid component. If it is good, an appropriate amount may be added. Examples of conductive salts include potassium thiocyanate, lithium nitrate, ammonium thiocyanate, dimethylamine hydrochloride and the like.

(solvent)
The solvent can be used for improving the polarity, viscosity, surface tension, solubility and dispersibility of the coloring material, adjusting the conductivity and adjusting the printing performance. The solvent is preferably a water-insoluble liquid and does not contain an aqueous solvent from the viewpoint of ink droplet ejection stability and quick drying, and the above-described high boiling point organic solvents are particularly preferable.

  The low boiling point organic solvent is an organic solvent having a boiling point of 100 ° C. or lower. There is a concern that the low boiling point organic solvent affects the curability, and it is desirable not to use the low boiling point organic solvent in consideration of environmental pollution. When used, it is preferable to use a highly safe solvent, and a highly safe solvent is a solvent having a high management concentration (an index indicated by the work environment evaluation criteria), preferably 100 ppm or more, More preferably, it is 200 ppm or more. Specific examples include alcohols, ketones, esters, ethers, hydrocarbons, and the like, and specific examples include methanol, 2-butanol, acetone, methyl ethyl ketone, ethyl acetate, and tetrahydrofuran.

  One or a plurality of solvents may be used in combination, and the amount used in the case of using the water and / or low boiling point organic solvent is preferably 0 to 20% by mass, and 0 to 10% by mass in each liquid. More preferably, it is particularly preferred that it is substantially free. Here, “substantially not containing” means accepting the presence of inevitable impurities. When water is contained in the liquid, the time stability that the liquid becomes turbid due to non-uniformity over time, precipitation of the dye, etc., and the viewpoint of the drying property when using a non-water-absorbing recording medium Is not preferable.

(Other additives)
As other additives, known additives such as a solvent, a polymer, a surface tension adjuster, an ultraviolet absorber, an antioxidant, a fading inhibitor, and a pH adjuster can be used in combination.
Regarding the surface tension adjusting agent, ultraviolet absorber, antioxidant, anti-fading agent, and pH adjusting agent, known compounds may be appropriately selected and used. For example, JP-A-2001-181549 discloses a specific example. The additives described can be used.

In addition to the above, a set of compounds that react by mixing to form aggregates or thicken can be contained in different liquids. The set of compounds has a feature of rapidly forming aggregates or rapidly thickening the liquid, thereby more effectively suppressing occurrence of droplet ejection interference with adjacent droplets. be able to.
Examples of reaction of a set of compounds that react by mixing to produce aggregates or thicken are represented by acid / base reactions, hydrogen bonding reactions with carboxylic acid / amide group-containing compounds, and boronic acids / diols. Crosslinking reaction, reaction by electrostatic interaction with cations / anions, and the like.

<Inkjet image recording method>
Next, the inkjet image recording method of the present invention will be described.
The inkjet image recording method of the present invention uses a plurality of types of liquids including the first liquid and the second liquid described above, and simultaneously applies the first liquid and the second liquid onto the recording medium, Alternatively, an image is formed by applying either one first and the other after that.

In addition, the first liquid containing a compound having a molecular weight of 1000 or less having no coloring agent and having 2 or more carbamoyl groups and a compound having a molecular weight of 1000 or less having 2 or more carbamoyl groups, And a second liquid containing a colorant, it is possible to effectively suppress bleeding and thickening of the line width, and color separation with excellent stickiness and scratch resistance quality. An image without it can be obtained.
In the above, the second liquid containing the colorant is preferably applied onto the recording medium by jetting with an ink jet nozzle, and moreover, at the same time as or after applying the first liquid. The second liquid is preferably ejected by an ink jet nozzle from the viewpoints of suppression of bleeding and line width, as well as stickiness and scratch resistance.

(Liquid application means)
Here, the means for applying the first liquid onto the recording medium in the image recording method will be described. As described above, the second liquid applying means will be described by way of example of jetting with an ink jet nozzle, which is a preferred embodiment.
The providing means is not particularly limited, but specific examples include the following two points.

(I) Coating using a coating device In the inkjet image recording method of the present invention, a first liquid is coated on a recording medium using a coating device, and then the second liquid is ejected by an inkjet nozzle. A mode of forming an image is preferable.
The coating device is not particularly limited and may be appropriately selected from known coating devices according to the purpose. For example, IP doctor coater, blade coater, rod coater, knife coater, squeeze coater, impregnation coater, reverse roll coater , Transfer roll coater, gravure coater, kiss roll coater, cast coater, spray coater, curtain coater, extrusion coater and the like. For other coating techniques, you can refer to “Coating Engineering” by Yuji Harasaki.
Moreover, there is no restriction | limiting in particular as said inkjet nozzle, A well-known nozzle can be suitably selected according to the objective.

  Here, an ejection method (inkjet recording method) by the inkjet nozzle will be described. In the present invention, for example, a charge control method that ejects ink using electrostatic attraction, a drop-on-demand method (pressure pulse method) that uses the vibration pressure of a piezo element, and an electric signal is converted into an acoustic beam into ink. Known systems such as an acoustic ink jet system that irradiates and discharges ink using radiation pressure, and a thermal ink jet (bubble jet (registered trademark)) system that uses ink to form bubbles by heating ink and generate pressure Are preferably used.

The ink jet recording method includes a method of ejecting a large number of low-density inks called photo inks in a small volume, a method of improving the image quality using a plurality of inks having substantially the same hue and different concentrations, and a colorless and transparent type. A method using ink is included.
Further, the liquid other than the first liquid and the second liquid may be applied onto the recording medium by any method such as application by the application device or injection by an ink jet nozzle, and the application timing is particularly high. Although it is not necessarily limited, when it contains a coloring agent, the means by the injection with an inkjet nozzle is preferable, and it is preferable to apply | coat after apply | coating a 1st liquid.

(Ii) Ejection by Inkjet Nozzle A mode in which an image is formed by ejecting the first liquid by an inkjet nozzle and simultaneously or subsequently ejecting the second liquid by an inkjet nozzle is preferable.
The ink jet nozzle is the same as described above.
The ink set of the present invention is preferably a mode in which the means (ii), the means for applying the first liquid and the second liquid onto the recording medium, is ejected by an ink jet nozzle. It is more preferable that all other liquids are ejected from the inkjet nozzle. By ejecting with an inkjet nozzle, the excellent effect is remarkably exhibited.

In the case of the means (i), at least the second liquid is applied onto the recording medium already coated with the first liquid by such an ink jet recording method, and an image is formed. On the other hand, in the case of the means (ii), at least the first liquid and the second liquid are applied onto the recording medium simultaneously or sequentially by such an ink jet recording method to form an image.
When two or more kinds of liquids are ejected onto a recording medium by the ink jet recording method, the liquids are applied so as to contact each other. There is no restriction | limiting in particular in the aspect which 2 or more types of liquids contact, You may spray so that it may mutually adjoin, You may spray so that it may become the same area | region as the application | coating area | region of one liquid.

  The timing of jetting is arbitrary and may be simultaneous or sequential. However, in the case of jetting sequentially, the next liquid may be jetted within 1 second after jetting the first liquid. preferable. The mass of the droplet is not particularly limited and is selected according to the sharpness of the image to be formed. In general, the mass per droplet of one liquid is about 0.5 pl to 10 pl. Is preferred.

  In the present invention, as the ratio of the application amounts for a plurality of types of liquids for forming an image by one droplet ejection, in the case of the two-liquid type, the mass of the first liquid application amount and the second liquid application amount The ratio is preferably in the range of 0.5: 5 to 5: 0.5 from the viewpoint of reactivity and viscosity.

Note that the preferred physical properties of all liquids (inks) including the first liquid and the second liquid ejected onto the recording medium by the ink jet recording method differ depending on the printing apparatus. The viscosity (25 ° C.) is preferably 5 to 100 mPa · s, and more preferably 10 to 80 mPa · s. The surface tension of the ink composition is preferably 20 to 60 mN / m, and more preferably 30 to 50 mN / m.
More preferable physical properties are when the difference in viscosity (25 ° C.) is within 25 mPa · s and the difference in surface tension is within 20 mN / m in the relationship between the first liquid and the second liquid.

(Energy application process)
In the image recording method, from the viewpoint of obtaining excellent fixability, a step of fixing the image by applying energy after image formation can be provided. By applying energy, polymerization and curing reaction in the aggregate can be promoted, and a stronger image can be formed more efficiently. Such energy application is preferably performed by light irradiation or heating.

  By applying energy such as exposure and heating, the generation of active species due to decomposition of the polymerization initiator in the mixed liquid is promoted, and the increase in the active species and the temperature increase cause the polymerization of the polymerizable compound resulting from the active species. The polymerization curing reaction is accelerated.

In the present invention, ultraviolet light, visible light, or the like can be used as an exposure light source for proceeding polymerization of the polymerizable compound. In addition, energy can be applied by irradiating radiation other than light, for example, α rays, γ rays, X rays, electron beams, etc. Among them, it is cost and safety to use ultraviolet rays and visible rays. In view of the above, it is more preferable to use ultraviolet rays. The amount of energy required for the curing reaction varies depending on the type and content of the polymerization initiator, but is generally about 1 to 500 mJ / cm ² .

In addition, when energy is applied by heating, it is preferable to heat for 0.1 seconds to 1 second under the condition that the temperature of the recording medium surface is in a temperature range of 40 to 80 ° C.
This heating is performed using a non-contact type heating means, and preferably a heating means for passing through a heating furnace such as an oven, a heating means for performing whole surface exposure with ultraviolet light to visible light to infrared light, and the like. Used. Here, examples of the light source used for the exposure as the heating means include a metal halide lamp, a xenon lamp, a tungsten lamp, a carbon arc lamp, and a mercury lamp.

(recoding media)
In the present invention, both an ink-permeable recording medium and an ink-impermeable recording medium can be used. Examples of the ink-permeable recording medium include plain paper, inkjet exclusive paper, coated paper, electrophotographic co-paper, cloth, non-woven fabric, porous film, polymer absorber and the like. These are described as “recording materials” in Japanese Patent Application Laid-Open No. 2001-181549.

  The excellent effect of the present invention is remarkably exhibited in an ink-impermeable recording medium. Examples of the ink-impermeable recording medium include art paper, synthetic resin, rubber, resin-coated paper, glass, metal, ceramics, and wood. In addition, in order to add a function, a base material obtained by combining and combining a plurality of these materials can also be used.

As the synthetic resin, any synthetic resin can be used. For example, polyesters such as polyethylene terephthalate and polybutadiene terephthalate, polyolefins such as polyvinyl chloride, polystyrene, polyethylene, polyurethane, and polypropylene, acrylic resins, polycarbonates, acrylonitrile-butadiene- Examples include styrene copolymer, diacetate, triacetate, polyimide, cellophane, celluloid, etc. The thickness and shape of these synthetic resin substrates may be in the form of a film, card or block, and are not limited in any way. Never happen. These synthetic resins may be transparent or opaque.
As a usage form of the synthetic resin, it is also preferable to use a film used for so-called soft packaging, and various non-absorbable plastics and films thereof can be used. Examples of various plastic films include PET films and OPS films. , OPP film, PNy film, PVC film, PE film, TAC film and the like. As other plastics, polycarbonate, acrylic resin, ABS, polyacetal, PVA, rubbers and the like can be used.

  Examples of the resin-coated paper include a transparent polyester film, an opaque polyester film, an opaque polyolefin resin film, and a paper support obtained by laminating both sides of a paper with a polyolefin resin. Particularly preferred is a polyolefin resin on both sides of the paper. It is a paper support laminated with.

Hereinafter, a paper support laminated with polyethylene, which is representative of the most preferred polyolefin, will be described.
As the base paper used for the paper support, wood pulp is used as a main raw material, and paper is made using synthetic pulp such as polypropylene or synthetic fiber such as nylon or polyester in addition to wood pulp as necessary. As the wood pulp, any of LBKP, LBSP, NBKP, NBSP, LDP, NDP, LUKP, and NUKP can be used, but it is preferable to use more LBKP, NBSP, LBSP, NDP, and LDP with a large amount of short fibers. preferable. However, the ratio of LBSP and / or LDP is preferably 10% by mass or more and 70% by mass or less.
The pulp is preferably a chemical pulp (sulfate pulp or sulfite pulp) with few impurities, and a pulp having a whiteness improved by bleaching is also useful.

  In the base paper, sizing agents such as higher fatty acids and alkyl ketene dimers, white pigments such as calcium carbonate, talc and titanium oxide, paper strength enhancing agents such as starch, polyacrylamide and polyvinyl alcohol, fluorescent whitening agents, polyethylene glycols A water retaining agent such as a dispersant, a softening agent such as a quaternary ammonium, and the like can be appropriately added.

  The freeness of the pulp used for papermaking is preferably 200 to 500 ml as defined by CSF, and the fiber length after beating is a 24 mesh residual mass and a 42 mesh residual mass defined in JIS P8207. 30 to 70 mass% is preferable. In addition, it is preferable that the mass% of 4 mesh remainder is 20 mass% or less.

The basis weight of the base paper is preferably 30 to 250 g, and particularly preferably 50 to 200 g. The thickness of the base paper is preferably 40 to 250 μm. The base paper can be given a high smoothness by calendering at the paper making stage or after paper making. The density of the base paper is generally 0.7 to 1.2 g / m ² (according to the method defined in JIS P8118).
Furthermore, the base paper stiffness is preferably 20 to 200 g under the conditions specified in JIS P8143 (1998 edition).

A surface sizing agent may be applied to the surface of the base paper. As the surface sizing agent, the same sizing agents that can be added to the base paper can be used.
The pH of the base paper is preferably 5 to 9 when measured by a hot water extraction method defined in JIS P8113 (1998 edition).

  The polyethylene covering the front and back surfaces of the base paper is mainly low-density polyethylene (LDPE) and / or high-density polyethylene (HDPE), but some other LLDPE, polypropylene, etc. can also be used.

  The polyethylene layer on the coating layer side is preferably one in which rutile or anatase type titanium oxide is added to polyethylene to improve opacity and whiteness, as is widely done in photographic paper. Here, as a titanium oxide content, about 1-20 mass% is preferable with respect to polyethylene, and 2-15 mass% is more preferable.

  Polyethylene-coated paper can be used as glossy paper, or matte or silky surface that can be obtained with ordinary photographic printing paper by applying a so-called molding process when polyethylene is melt-extruded and coated on the base paper surface. Those formed can also be used.

  The amount of polyethylene used on the front and back of the base paper is selected to optimize the film thickness of the aqueous coating composition and the curl under low and high humidity after providing the back layer, but the aqueous coating according to the present invention The polyethylene layer on the side on which the composition is applied is preferably 20 to 40 μm, and the back layer side is preferably in the range of 10 to 30 μm.

  Any metal can be used as the metal, but these composite materials such as aluminum, iron, gold, silver, copper, nickel, titanium, chromium, molybdenum, silicone, lead, zinc, or stainless steel are preferable. Used.

EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not restrict | limited to these.
(Example)
An ink jet recording ink as shown below was prepared and the same experiment was performed. Below, the prescription of the ink liquid using a pigment is shown.

<Preparation of Inkjet Recording Liquid (I-0) Containing Polymerizable Compound>
(A) <the following compound (Ac-1), molecular weight 8000>: 0.22 g
(B) Polymerizable compound: DPCA60 (Nippon Kayaku): 0.38 g
(C) Polymerizable compound: 1,6 hexanediol diacrylate: 11.60 g
(HDDA manufactured by Daicel UBC)
(D) N-ethyldiethanolamine: 0.20 g
(E) Colorant <Pigment: Copper phthalocyanine PB15: 3>: 1.40 g
The above components were mixed and dissolved with stirring to obtain a pigment cyan ink liquid (I-0). The viscosity of the liquid (I-0) was 19.6 mPa · s.

<Preparation of Inkjet Recording Liquid (I-1) Containing Polymerizable Compound>
An ink jet recording liquid (I-) was prepared in the same manner as the preparation of the ink jet recording liquid (I-0) containing a polymerizable compound except that 0.22 g of the acid compound (the compound (Ac-1)) was not used. 1) was obtained. When the viscosity was measured in the same manner as for I-0, the viscosity at 25 ° C. was 15.0 mPa · s.

<Preparation of Ink Composition for Inkjet Recording (II-1) Containing a Compound with a Molecular Weight of 1000 or Less Having Two or More Carbamoyl Groups>
(E) High boiling point organic solvent (Exemplary Compound (S-15)): 10 g
(F) The following polymerization initiator (TPO-L (initiator-1)): 1.8 g
(G) Compound having 2 or more carbamoyl groups and having a molecular weight of 1000 or less: 2 g
(Exemplary Compound 1-1)

<Preparation of ink compositions for ink jet recording (II-2) to (II-9) containing a compound having a molecular weight of 1,000 or less and having two or more carbamoyl groups>
In the preparation of the ink composition for ink-jet recording (II-1) containing a compound having a molecular weight of 1,000 or less and having two or more carbamoyl groups, Exemplified Compound 1-1 was replaced with the compound shown in Table 1 having the same mass. Prepared ink-jet recording liquids (II-2) to (II-9) in the same manner as the ink-jet recording ink composition (II-1). Table 1 shows the viscosity at 25 ° C. of compounds having a molecular weight of 1,000 or less having two or more carbamoyl groups used for the preparation of each ink composition, and liquids.

<Comparative ink liquid I-00 for one-component ink jet recording>
(A) Polymerizable compound: DPCA60 (Nippon Kayaku): 0.38 g
(B) Polymerizable compound: 1,6 hexanediol diacrylate: 11.60 g
(HDDA manufactured by Daicel UBC)
(C) N-ethyldiethanolamine: 0.20 g
(D) Colorant <Pigment: Copper phthalocyanine PB15: 3>: 1.40 g
(E) High boiling point organic solvent (Exemplary Compound (S-15)): 12.10 g
(F) Polymerization initiator (TPO-L (Exemplary compound-Initiator-1)): 1.81 g

<Comparative ink liquid I-000 for one-component inkjet recording>
(A) Polymerizable compound: DPCA60 (Nippon Kayaku): 0.38 g
(B) Polymerizable compound: 1,6 hexanediol diacrylate: 11.60 g
(HDDA manufactured by Daicel UBC)
(C) N-ethyldiethanolamine: 0.20 g
(D) Colorant <Pigment: Copper phthalocyanine PB15: 3>: 1.40 g
(E) High boiling point organic solvent (Exemplary Compound (S-15)): 10.10 g
(F) Polymerization initiator (TPO-L (Exemplary compound-Initiator-1)): 1.81 g
(G) N, N-dimethylaminopropylacrylamide: 2.0 g

<Comparison ink liquid for two-component ink jet recording (II-0)>
(A) Ethyl acetate: 10.0 g
(B) Polymerization initiator (TPO-L (Initiator-1)): 1.8 g
(C) N, N-dimethylaminopropylacrylamide: 2.0 g

<Evaluation>
The ink compositions (II-1) to (II-9) and (II-0) thus prepared were used as inkjet printers (microjet experimental machine, printing density: 300 dpi, droplet ejection frequency: 2 KHz, number of nozzles: 64, 2 Printed on the recording medium. Thereafter, the ink liquid (I-0) was printed so as to overlap the ink compositions (II-1) to (II-9) and (II-0) applied to the recording medium.
Similarly, the ink liquid (I-1) was printed so as to overlap the ink compositions (II-1) to (II-9) and (II-0).

The produced ink liquid (I-00) was printed on a recording medium with an ink jet printer (an experimental machine manufactured by Microjet Co., print density: 300 dpi, droplet ejection frequency: 2 KHz, number of nozzles: 64, two-row arrangement). In this case, however, only I-00 was printed alone.
The produced ink liquid (I-000) was printed in the same manner as the ink liquid (I-00). However, the droplet ejection frequency was 4 KHz. In this case, however, only I-000 was printed alone. At this time, the comparative ink I-000 was clogged with nozzles and could not be stably discharged.

As recording media, a polyethylene terephthalate (PET) sheet having a thickness of 60 μm, (trade name: PPL / Xerox film for laser printers, OHP FILM, manufactured by Fuji Xerox Co., Ltd.) and art paper (trade name: Tokuhishi art both sides, Mitsubishi paper Used).
After printing for 60 seconds, a metal halide lamp with a wavelength of 365 nm was used, and ultraviolet irradiation was performed at an ultraviolet light amount of ~ 500 mJ / cm ² . An image was formed. The obtained image was evaluated on the following items. The results are shown in Table 2.

<Evaluation of droplet ejection interference performance>
(Line thickness)
Liquid I and II liquids were overlaid in a line shape, and the condition of the droplet ejection shape was evaluated according to the following criteria when there was a time interval between exposure after printing. However, for (I-0) and (I-00), only one solution was ejected in a line.
A: The thickness of the line is uniform and is 0.3 mm or less.
(0.3 mm is approximately three times the spread. Here, the spread is a ratio to the ink droplet diameter just before reaching the recording medium.)
B: The line thickness is uniform, but the line thickness exceeds 0.3 mm.
C: There is a clear line variation from the liquid pool on the line.

<Sticky evaluation>
The printed surface was touched with a finger and evaluated according to the following criteria.
A: No stickiness B: Slightly sticky C: Remarkably sticky

<Abrasion resistance evaluation>
The PET or art paper on which the image was formed was rubbed 10 times with an eraser for an image 30 minutes after printing, and the change was observed and evaluated according to the following criteria.
A: No decrease in density B: Slight decrease in density C: Remarkable decrease in density

  From Table 2, an ink set comprising at least a first liquid and a second liquid and comprising a plurality of types of liquids, the first liquid containing a compound having a molecular weight of 1000 or less having two or more carbamoyl groups Then, it can be seen that the droplet ejection interference performance, stickiness and scratch resistance are all good.

Claims (23)

  An ink composition comprising a compound having two or more carbamoyl groups and having a molecular weight of 1,000 or less. 2. The ink composition according to claim 1, wherein the compound having two or more carbamoyl groups and having a molecular weight of 1,000 or less is a compound represented by the following general formula (1) or (2).

(In the general formulas (1) and (2), R _{1 to} R ₈ each independently represents a hydrogen atom, an alkyl group or an aryl group. L ₁ represents an n + 1 valent linking group, and L ₂ represents an m + 1 valent linking group. M and n represent an integer of 1 or more.) 3. At least _one of R ₁ and R ₄ in the general formula (1), or at least one of R ₆ and R ₇ in the general formula (2) is a hydrogen atom. Ink composition.   The ink composition according to claim 1, further comprising a polymerization initiator. The ink composition according to claim 1, comprising a high-boiling organic solvent that satisfies the following conditions (1) and (2).
Condition (1): The viscosity at 25 ° C. is 100 mPa · s or less, or the viscosity at 60 ° C. is 30 mPa · s or less.
Condition (2): The boiling point is higher than 100 ° C.   The ink composition according to claim 1, wherein the ink is for inkjet recording.   An ink set comprising at least a first liquid and a second liquid and comprising a plurality of types of liquids, wherein the first liquid contains a compound having a molecular weight of 1000 or less having two or more carbamoyl groups. Ink set. The ink set according to claim 7, wherein the compound having a molecular weight of 1000 or less and having two or more carbamoyl groups is a compound represented by the following general formula (1) or (2).

(In the general formulas (1) and (2), R _{1 to} R ₈ each independently represents a hydrogen atom, an alkyl group or an aryl group. L ₁ represents an n + 1 valent linking group, and L ₂ represents an m + 1 valent linking group. M and n represent an integer of 1 or more.) 9. At least _one of R ₁ and R ₄ in the general formula (1), or at least one of R ₆ and R ₇ in the general formula (2) is a hydrogen atom. Ink set.   The ink set according to claim 7, wherein the second liquid contains a polymerizable or crosslinkable material.   The ink set according to claim 7, wherein the second liquid contains a colorant.   The content of the colorant in the first liquid is an amount that is 0 or more and 0.5 or less in terms of the solution absorbance at the maximum absorption wavelength when transmitted through an ink solution having a thickness of 1 cm. The ink set according to any one of claims 7 to 11. The high-boiling organic solvent satisfying the following conditions (1) and (2) is contained in at least one of the first liquid or the second liquid. The ink set described.
Condition (1): The viscosity at 25 ° C. is 100 mPa · s or less, or the viscosity at 60 ° C. is 30 mPa · s or less.
Condition (2): The boiling point is higher than 100 ° C.   The ink set according to claim 13, wherein the high-boiling organic solvent is contained in the first liquid.   The ink set according to claim 7, wherein the colorant is a pigment.   The ink set according to claim 7, wherein a water-insoluble liquid is used as the plurality of types of liquid solvents.   The ink set according to any one of claims 7 to 16, wherein the ink set is for inkjet recording.   The ink set according to any one of claims 7 to 17, which includes at least a first liquid and a second liquid, and is composed of a plurality of types of liquids, wherein the first liquid and the second liquid are used. An inkjet image recording method in which an image is formed by applying simultaneously on a recording medium, or by applying either one first and the other after that.   19. The inkjet image recording method according to claim 18, wherein an image is formed by ejecting the second liquid by an inkjet nozzle at the same time as or after applying the first liquid onto the recording medium.   19. The means for applying the first liquid onto the recording medium is coating using a coating device, and the second liquid is ejected by an inkjet nozzle after coating the first liquid. Or the inkjet image recording method of 19.   The inkjet image recording method according to any one of claims 18 to 20, wherein the means for applying the first liquid and the second liquid onto the recording medium is ejection by an inkjet nozzle.   The inkjet image recording method according to any one of claims 18 to 21, further comprising a step of fixing energy by applying energy to an image formed on a recording medium.   The inkjet image recording method according to claim 22, wherein the energy is applied by light irradiation or heating.