JPWO2016052144A1 - Non-aqueous ink composition, image forming method, and printed matter using the same - Google Patents

Abstract

The non-aqueous ink composition contains an ink-soluble polymer fluorescent dye having a site that emits fluorescence in a repeating unit and an organic solvent, and does not substantially absorb visible light. The image forming method includes an ink application step of applying the non-aqueous ink composition onto a recording medium, and a step of drying the non-aqueous ink composition applied onto the recording medium. The printed matter has an image formed by applying the non-aqueous ink composition or recorded by the image forming method.

Description

  The present invention relates to a non-aqueous ink composition, an image forming method, and a print using the same.

  The image recording method based on the ink jet method is an image recording method in which an ink composition (ink) is ejected from a droplet ejection head based on an image data signal, and an image is directly formed on a recording medium such as paper. The ink jet method does not require a printing plate, and has an advantage that ink can be used efficiently and running cost is low because ink is ejected only to the required image portion. Furthermore, the image recording apparatus is also relatively inexpensive, can be downsized, and has low noise. As described above, the ink jet method is excellent in various respects as an image recording method.

Among the ink compositions used for image recording by the ink jet method, the water-based ink composition has low odor and is excellent in safety, so that it is widely used not only for industrial use but also for home use. In recent years, with the advancement of inkjet technology, it has become possible to easily create high-definition, high-color, high-quality images. For this reason, it is possible to easily duplicate a printed matter, and it is desired to develop a genuine appraisal means in order to prevent unauthorized duplication. In addition, with the automation of product management and delivery, the development of means for entering information on products and cargo packaging without deteriorating the appearance of the printed object is also underway. As an ink composition suitable for such an application, a colorless ink composition containing an invisible fluorescent dye can be given. In this method, information can be written without damaging the appearance by irradiating light of a specific wavelength and reading a light emission pattern, so authenticity information, product information, transportation information, etc. are printed invisible and read. It is possible.
For example, Patent Document 1 proposes to use a water-based ink using a fluorescent dye such as rhodamine B.

JP 58-49765 A

However, in the water-based ink described in Patent Document 1, since the fluorescent dye has a low molecular weight, if the binder is not used in combination, the image may be peeled off, or the dye may penetrate into the recording medium and blur may occur. There was a problem with the stability of the image under wet conditions. In addition, the water-based ink described in Patent Document 1 has improved rub resistance on a permeation base, but when printing on a non-penetration base, the ink composition does not fix on the recording medium, and the base There was a problem of poor adhesion and abrasion resistance. Furthermore, when printing is performed on a substrate such as inkjet paper where bleeding is difficult to suppress, there is a problem that blurring occurs and a clear image cannot be obtained.
On the other hand, when the processing time for drying and fixing ink becomes shorter as the speed of the apparatus increases, the next recording medium is overlaid on the recording medium on which the recorded image is not dried. In this case, a phenomenon of stacker blocking in which the previous recorded image is transferred to the back surface of the next recording medium or the recording media stick to each other occurs. Resistance to such a phenomenon is called blocking resistance. In order to prevent this, ink that dries and fixes quickly is required.

  The present invention has been made in view of the above circumstances, and is a non-aqueous ink composition that has fluorescence and emits light with little blur when recording an image, and provides a uniform image quality. In addition, the present invention provides a non-aqueous ink composition having good substrate adhesion even when printed on a non-permeable substrate, excellent image abrasion resistance, and excellent image fastness and blocking resistance under high humidity conditions. For the purpose. It is another object of the present invention to provide an image forming method using the non-aqueous ink composition of the present invention, a non-aqueous ink composition of the present invention, and a print obtained by the image forming method.

  The present inventors have described in detail the phenomenon with respect to the substrate when using a composition in which a conventional fluorescent colorant (fluorescent dye) or pigment is dispersed in a solvent, or a composition in which polymer fine particles are incorporated as an emulsion or latex. It was examined. As a result, the present invention is based on the knowledge that an ink composition is excellent in various properties by incorporating a polymer in which a fluorescent dye is chemically bonded to the composition, that is, a polymer fluorescent dye in a dissolved state. It came.

The above problem has been solved by the following means.
<1> A non-aqueous ink composition which contains an ink-soluble polymer fluorescent dye having a fluorescent site in a repeating unit and an organic solvent and does not substantially absorb visible light.
<2> The non-aqueous ink composition according to <1>, wherein the glass transition temperature of the polymeric fluorescent dye is 40 ° C. or higher.
<3> The nonaqueous ink according to <1> or <2>, wherein the content of the polymeric fluorescent dye is 0.5% by mass or more and 5.0% by mass or less with respect to the total mass of the nonaqueous ink composition. Composition.
<4> The non-aqueous ink composition according to any one of <1> to <3>, wherein the polymer fluorescent dye has a repeating unit represented by the following general formula (1).

In General Formula (1), R ¹ represents a hydrogen atom or a methyl group, and X represents a phenylene group, —COO—, or —CONR ² —. Here, R ² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y represents a single bond or a linear or branched alkylene group having 1 to 8 carbon atoms. In the alkylene group, —O—, —OC (═O) —, —CH (OH) —, —NH—, Alternatively, -NHC (= O)-may be included. Z represents a fluorescent dye residue.
<5> The content of the repeating unit represented by the general formula (1) in the polymer fluorescent dye is 5% by mass or more and 30% by mass or less with respect to the total mass of the polymer fluorescent dye, according to <4>. Non-aqueous ink composition.
<6> The non-aqueous ink composition according to any one of <1> to <5>, which is for inkjet.
<7> An ink application step of applying the nonaqueous ink composition according to any one of <1> to <6> onto a recording medium, and drying the nonaqueous ink composition applied onto the recording medium. And an image forming method.
<8> A printed matter formed on the recording medium by the non-aqueous ink composition according to any one of <1> to <6>.
<9> A printed matter having an image recorded by the image forming method according to <7>.

In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value.
In this specification, “(meth) acrylate” represents both and / or acrylate and methacrylate, and “(meth) acryl” represents both and / or acryl and methacryl.
In this specification, the term “process” is not limited to an independent process, and is included in the term if the intended action of the process is achieved even when it cannot be clearly distinguished from other processes. .

According to the present invention, a clear and uniform image quality in which bleeding of an image recorded by the ink jet method is suppressed is obtained, excellent in abrasion resistance, and furthermore, when stored under a high humidity condition, blocking resistance. A non-aqueous ink composition having good substrate adhesion and image fastness can be provided.
In addition, according to the present invention, bleeding of an image to be recorded is suppressed, the image is excellent in abrasion resistance, and further has good blocking resistance and excellent substrate adhesion and image fastness when stored under high humidity conditions. An image forming method capable of forming an image and a printed matter in which bleeding is suppressed, excellent in abrasion resistance, blocking resistance, fastness and glossiness can be provided.

<< Non-aqueous ink composition >>
The non-aqueous ink composition of the present invention (hereinafter, also simply referred to as “ink composition” or “ink”) has an ink-soluble polymer fluorescent dye (hereinafter referred to as “high-density fluorescent dye”) having a site that emits fluorescence in a repeating unit. And a non-aqueous ink composition that contains an organic solvent and does not substantially absorb visible light.

In the present invention, the “ink-soluble polymer” does not exist in a non-aqueous ink composition in the form of particles or fine particles, but dissolves in an organic solvent in the non-aqueous ink composition to form particles. When the ink composition is measured with a particle size measuring device such as a dynamic light scattering device, the particle size is not observed. In the present invention, a dense particle size analyzer FPAR-1000 manufactured by Otsuka Electronics Co., Ltd. was used. As the numerical values of the viscosity and the refractive index used for the measurement, the numerical values of the refractive index and the viscosity of the liquid component in the ink composition were used.
In other words, the ink-soluble polymer does not exist in the form of fine particles dispersed in a composition by dispersing fine particles with a surfactant, but a latex or emulsified dispersion in which insoluble fine particles are dispersed in the composition. It differs from the aspect of inclusion.
Further, the “non-aqueous ink composition” means an ink composition that does not substantially contain water in the ink composition, and the water content in the ink composition is relative to the total amount of the ink composition. It is preferably 1.0% or less, and more preferably 0.5% or less.

  Further, “substantially does not absorb visible light” means that it does not substantially absorb light in the visible light wavelength region. In the present invention, an ultraviolet-visible spectrophotometer is used, and it is 2000 times as large as the ink composition. When the absorbance in the visible light region (380 to 780 nm) of the diluted product is measured, it means that the absorbance value is less than 0.2. In this invention, the value measured in the range of 380 nm-780 nm using Shimadzu Corp. make and ultraviolet visible spectrophotometer UV-2550 is used. When printing is performed using such an ink composition, it is possible to obtain a printed material in which the printed portion and the non-printed portion cannot be distinguished under the condition where the excitation light is not irradiated. In this specification, the fact that such a printed part cannot be distinguished from a non-printed part may be described as “invisible”.

  As a result, when printing is performed using the non-aqueous ink composition of the present invention, since the polymer fluorescent dye is contained in the ink composition, the printed portion is invisible when the printed matter is observed with visible light. However, when the printed matter is irradiated with excitation light such as ultraviolet light, the fluorescent portion in the polymer fluorescent dye emits fluorescence, and necessary character information and image information can be read out.

In the present invention, by using an ink-soluble polymer fluorescent dye, the mechanism of action that cannot be obtained with a fine particle dispersion of the polymer fluorescent dye is not clear, but is presumed as follows.
In ink-jet printing, in order to obtain a high-definition image without bleeding, it is necessary to prevent liquid diffusion in the in-plane direction of the base material in a permeable base material such as paper. When low-molecular fluorescent dyes or particulate fluorescent dyes are used for low-viscosity inks, it is estimated that bleeding occurs because the ink droplets maintain low viscosity after landing on the substrate. Is done.
On the other hand, when the ink-soluble polymer fluorescent dye of the present invention is used, when the ink droplets land on the substrate, the viscosity rapidly increases with the progress of penetration and drying. It is presumed that the penetration of the ink is suppressed and the bleeding can be reduced. Further, even when a non-permeable base material such as vinyl chloride is used, bleeding can be suppressed due to the characteristic that the viscosity rapidly increases. Furthermore, when printed on a non-permeable substrate, the polymer fluorescent dye is a polymer compound, so that it has film-forming properties and is excellent in adhesion to a printing material and abrasion resistance.

<Ink-soluble polymer fluorescent dye having a fluorescent site in the repeating unit>
The ink composition of the present invention contains at least an ink-soluble polymer fluorescent dye having a fluorescent site in a repeating unit.
The polymeric fluorescent dye of the present invention is a polymeric compound that has a fluorescent site in its repeating unit and dissolves in the ink composition. By dissolving in the ink composition, the viscosity increases in the drying step, and bleeding can be suppressed. The polymer compound in the present invention refers to a compound in which three or more monomer units are bonded by a covalent bond and does not have a single molecular weight.

The polymeric fluorescent dye of the present invention has a site emitting fluorescence in a repeating unit. A known fluorescent dye that substantially does not absorb visible light can be arbitrarily selected as the site that emits fluorescence. By dissolving a polymer fluorescent dye obtained by introducing a fluorescent dye into a polymer compound in the ink, unevenness caused by precipitation in the ink or crystallization during drying can be effectively suppressed. As the fluorescent dye to be introduced into the polymer compound, an organic fluorescent dye is preferable, and among them, an acridone dye, a fluorescein dye, a rhodamine dye, a 9-hydroxyphenanthrene dye, an acridine dye, a coumarin dye, a benzofurazan dye, a resorufin dye, and a dansyl dye. Benzofuran dye, cyanine dye, merocyanine dye, rhodacyanine dye, oxonol dye, styryl dye, pyromethene dye, and the like.
Among these, an acridone dye, a fluorescein dye, a rhodamine dye, a 9-hydroxyphenanthrene dye, a coumarin dye, a benzofuran dye, a merocyanine dye, a styryl dye, and an acridine dye are preferable, and an acridone dye, a coumarin dye, and a fluorescein dye are more preferable.

  The polymeric fluorescent dye in the present invention is preferably a polymeric compound having a repeating unit represented by the following general formula (1).

In General Formula (1), R ¹ represents a hydrogen atom or a methyl group, and X represents a phenylene group, —COO—, or —CONR ² —. Here, R ² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y represents a single bond or a linear or branched alkylene group having 1 to 8 carbon atoms. In the alkylene group, —O—, —OC (═O) —, —CH (OH) —, —NH—, Alternatively, -NHC (= O)-may be included. Z represents a fluorescent dye residue.

  The polymeric fluorescent dye in the present invention is prepared by synthesizing a monomer having an ethylenically unsaturated group (for example, a vinyl group, acryloyl or methacryloyl group) having a fluorescent dye moiety that gives a repeating unit represented by the general formula (1) Depending on the case, it is preferably produced by copolymerization with other vinyl monomers.

R ¹ is preferably a hydrogen atom.

X represents a phenylene group, —COO—, or —CONR ² —. Here, R ² represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, preferably a hydrogen atom. X is preferably a phenylene group or —COO— from the viewpoint of polymerizability.

  Y represents a single bond, a linear or branched alkylene group having 1 to 8 carbon atoms, and in the alkylene group, —O—, —OC (═O) —, —CH (OH) —, —NH—, — NHC (= O)-may be contained. 1-6 are more preferable and, as for carbon number of Y, 1-4 are the most preferable.

The repeating unit represented by the general formula (1) in the present invention is a polymerization of a monomer having an ethylenically unsaturated group (for example, a vinyl group, acryloyl or methacryloyl group) that gives the repeating unit represented by the general formula (1). Or it can synthesize | combine by reaction with the polymer which has the reactive functional group (beta) which reacts with this specific functional group (alpha) in the side chain, and the compound which has a fluorescent dye part and specific functional group (alpha).
In the former case, a monomer having an ethylenically unsaturated group and a fluorescent dye portion is synthesized in advance. This monomer includes, for example, a fluorescent dye having a reactive functional group γ, a monomer having a reactive functional group δ and an ethylenically unsaturated group that react with the reactive functional group γ by an addition reaction, a substitution reaction, or a condensation reaction. Can be synthesized. On the other hand, in the latter case, a polymer is synthesized in advance with a monomer unit having a reactive functional group β, and a fluorescent dye having a specific functional group α that reacts with the reactive functional group β by an addition reaction, a substitution reaction or a condensation reaction; By this reaction, a fluorescent dye site is introduced into the polymer.
That is, Y is a partial structure formed by the reaction of a reactive functional group site in the monomer or polymer and a reactive site in the fluorescent dye or a structure containing this.

Preferable specific examples of Y include a single bond, a linear or branched alkyl group having 1 to 8 carbon atoms, —CH ₂ CH ₂ O—, —CH ₂ CH ₂ OCH ₂ —, —CH ₂ CH (OH) CH. ₂ O—, —CH ₂ CH (OH) CH ₂ NH—, —CH ₂ CH (OH) CH ₂ OCH ₂ —, —CH ₂ OCH ₂ CH (OH) CH ₂ O—, —CH ₂ CH ₂ OCH _{2 CH (OH) CH 2 O -} , - CH 2 CH 2 C (= O) OCH 2 CH (OH) CH 2 O -, - CH 2 CH 2 OC (= O) CH 2 CH 2 C (= O) OCH ₂ CH (OH) CH ₂ O—, —CH ₂ CH ₂ NHC (═O) OCH ₂ —, —CH ₂ CH ₂ NHC (═O) OCH ₂ CH ₂ —, —CH ₂ CH ₂ NHC (═O) NH—, —CH ₂ CH ₂ NHC (═O) NHCH ₂ — Etc.

Z represents a fluorescent dye residue. As the fluorescent dye residue, a group obtained by removing one hydrogen atom from a known fluorescent dye can be arbitrarily selected, but it can be easily introduced into a polymer compound, and can be dissolved in an ink composition and can be stored stably. The fluorescent dye is preferably an organic fluorescent dye from the viewpoint of the properties and the selectivity of the organic solvent of the ink composition.
Specifically, an acridone dye, fluorescein dye, rhodamine dye, 9-hydroxyphenanthrene dye, acridine dye, coumarin dye, benzofurazan dye, resorufin dye, dansyl dye, benzofuran dye, cyanine dye, merocyanine dye, rhodacyanine dye, oxonol dye, A group obtained by removing one hydrogen atom from a known fluorescent dye such as a styryl dye or a pyromethene dye is preferred. Among these, an acridone dye, a fluorescein dye, a rhodamine dye, a 9-hydroxyphenanthrene dye, a coumarin dye, a benzofuran dye, a merocyanine dye, a styryl dye, and a group obtained by removing one hydrogen atom from an acridine dye are more preferable. A group obtained by removing one hydrogen atom from a dye or a fluorescein dye is more preferable.

  Z is preferably a group represented by the following general formulas (a-1) to (a-5).

In general formulas (a-1) to (a-5), Ra to Rc each independently represents an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or a halogen atom. m1 and m2 each independently represents an integer of 0 to 4. m3 represents an integer of 0-2. L ¹ represents a single bond or a phenylene group. The ring to which L ¹ is bonded may be any of Cy ^{1 to} Cy ³ . A ¹ is = O or ^{= N + (Rd1) (Rd2} ) X α - represents, the X _alpha represents a halogen atom. A ² represents —OH or —N (Rd 1) (Rd 2). Here, Rd1 and Rd2 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. B ¹ represents a carbon atom or a nitrogen atom.

Specific examples of the repeating unit of the general formula (1) in the present invention include the following structures, but the present invention is not limited thereto.

  The content of the repeating unit of the general formula (1) that can be used in the polymer fluorescent dye used in the present invention is 5% by mass to 30% by mass with respect to all the repeating units constituting the polymer fluorescent dye. The range is preferable, and the range of 5% by mass to 20% by mass is more preferable.

The polymeric fluorescent dye in the present invention includes a repeating unit having no fluorescent moiety (hereinafter, appropriately referred to as “other repeating unit”) from the viewpoint of adjusting solubility, viscosity, and film performance. preferable.
The other repeating unit is not particularly limited as long as it is a repeating unit derived from a monomer having no hydrophilic group in the molecule. The other repeating unit may contain only 1 type and may contain 2 or more types. As a monomer which does not have a hydrophilic group, the monomer which contains at least 1 of a chain aliphatic group, a cyclic aliphatic group, and an aromatic group in a molecule | numerator, and does not contain a hydrophilic group is mentioned, for example. In addition, since the polymeric fluorescent dye in this invention does not have a crosslinked structure, it is required that other repeating units do not contain a crosslinkable group.

  Specific examples of monomers that form “other repeating units” (hereinafter sometimes referred to as “other copolymerizable monomers”) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl ( Alkyl (meth) acrylate such as (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, ethylhexyl (meth) acrylate, etc. ) Acrylate; aromatic ring-containing (meth) acrylates such as benzyl (meth) acrylate and phenoxyethyl (meth) acrylate; styrenes such as styrene, α-methylstyrene and chlorostyrene; dialkylamino such as dimethylaminoethyl (meth) acrylate Archi (Meth) acrylate; N-hydroxymethyl (meth) acrylamide, N-hydroxyethyl (meth) acrylamide, N-hydroxyalkyl (meth) acrylamide such as N-hydroxybutyl (meth) acrylamide; N-methoxymethyl (meth) acrylamide N-ethoxymethyl (meth) acrylamide, N- (n-, iso) butoxymethyl (meth) acrylamide, N-methoxyethyl (meth) acrylamide, N-ethoxyethyl (meth) acrylamide, N- (n-, iso ) (Meth) acrylamide such as N-alkoxyalkyl (meth) acrylamide such as butoxyethyl (meth) acrylamide.

The polymeric fluorescent dye in the present invention is preferably a vinyl polymer in view of the dischargeability and production suitability of the ink composition.
The polymeric fluorescent dye in the present invention can be obtained, for example, by a known polymerization method such as a radical polymerization method using a monomer having a hydrophilic group and a monomer having no hydrophilic group. The polymeric fluorescent dye of the present invention can also be obtained by neutralizing a part of the dissociable hydrophilic group among the hydrophilic groups with an alkali metal hydroxide or the like as necessary. A known radical polymerization method can be used for the polymeric fluorescent dye of the present invention without limitation.

  The polymeric fluorescent dye in the present invention preferably has a weight average molecular weight of 3,000 to 100,000, more preferably a weight average molecular weight of 5,000 to 80,000, and 5,000 to 50,000. 000 is particularly preferred. When adjusted to this range, it tends to be excellent in abrasion resistance and ejection properties and to suppress bleeding.

  The weight average molecular weight is measured by gel permeation chromatography (GPC). For GPC measurement, for example, HLC-8020GPC (manufactured by Tosoh Corporation) is used, and TSKgel SuperHZM-H, TSKgel SuperHZ4000, TSKgel SuperHZ200 (manufactured by Tosoh Corporation, 4.6 mm IDφ15 cm) are used as columns and THF (tetrahydrofuran) is used as an eluent. ) Can be used.

  The glass transition temperature (Tg) of the polymeric fluorescent dye in the present invention is preferably 40 ° C. or higher, more preferably 50 to 150 ° C., and most preferably 60 to 130 ° C. In this range, the mechanical properties of the film such as blocking resistance and abrasion resistance tend to be improved. The glass transition temperature can be measured by a known method, but in the present invention, a numerical value measured using a differential scanning calorimeter (DSC-6220, manufactured by Seiko Instruments Inc.) using 5 mg of the sample was used.

  The polymeric fluorescent dye in the invention is preferably contained in the range of 0.1% by mass to 20% by mass, more preferably 0.5% by mass to 10% by mass, with respect to the total amount of the ink composition. A mass% to 5 mass% is most preferred. Within this range, both color developability and dischargeability can be achieved. The ink composition of the present invention needs to be substantially invisible when the printed matter is not irradiated with excitation light. However, the polymer fluorescent dye that absorbs visible light is low so as to be substantially invisible. It can also be used by using in concentration.

<Organic solvent>
The ink composition of the present invention contains an organic solvent. Examples of the organic solvent include alcohol compounds, ketone compounds, ester compounds, lactone compounds, lactam compounds, carbonate compounds, ureido compounds, urethane compounds, amine compounds, glycol compounds, glycol ether compounds, aromatic compounds, hydrocarbon solvents, reactions. A known organic solvent such as a reactive diluent can be used.
Of these, ketone compounds, lactone compounds, lactam compounds, carbonate compounds, ureido compounds, urethane compounds, glycol compounds, and glycol ether compounds are preferred in the present invention.

(Ketone compound)
The organic solvent that can be used in the ink composition of the present invention is preferably a ketone compound. The ketone compound is preferable because it is chemically stable, has high solubility of the polymeric fluorescent dye and high solubility of the non-permeable base material, and can improve dischargeability and adhesion.
The ketone compound may be an aliphatic ketone compound or an aromatic ketone compound, but an aliphatic ketone compound is preferred.
The total number of carbon atoms of the ketone compound is preferably 3 to 10, more preferably 4 to 10, and still more preferably 4 to 7.
The ketone compound is preferably a compound represented by Rα-C (═O) —Rβ. Here, Rα and Rβ each independently represent an alkyl group having 1 to 5 carbon atoms, and may be linear or branched. Rα and Rβ may combine with each other to form a ring.
Examples of the ketone compound include acetone, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, pinacholine, diethyl ketone, ethyl n-propyl ketone, ethyl isopropyl ketone, diisobutyl ketone, isopropyl isobutyl ketone, and cyclohexanone.
Among these, methyl ethyl ketone, methyl isobutyl ketone, methyl isopropyl ketone, and cyclohexanone are preferable, and methyl ethyl ketone and cyclohexanone are more preferable.

(Glycol ether compound)
As the organic solvent that can be used in the ink composition of the present invention, a glycol ether compound is preferable. By further including a glycol ether compound in the ink composition of the present invention, the discharge properties and the like are further improved. Although this mechanism is not clear, it is presumed as follows. However, the following description is just a guess, and the present invention is not limited to this. By using a glycol ether compound as an organic solvent, by suppressing the precipitation of the ink composition by improving the solubility of the polymeric fluorescent dye, and the volatility of the solvent in the vicinity of the nozzle of the inkjet head, It is considered that the discharge properties and the like are further improved.

The glycol ether compound is a compound having the following structure in the molecule.

  In general formula (2), k represents 2 or 3. n represents an integer of 1 to 4.

  Examples of glycol ether compounds include monoalkyl ethers or dialkyl ethers of either polyoxyethylene glycol or polyoxypropylene glycol. Specifically, an organic solvent represented by the following general formula (α), (β) or (γ) is preferable.

  As the organic solvent, polyoxyethylene glycol dialkyl ether represented by the following general formula (α) (hereinafter also referred to as “compound represented by the general formula (α)”) is preferable.

^{_{R 21 - (OC 2 H 4}} ) na -OR 22 ··· formula (alpha)

In the general formula (α), R ²¹ and R ²² each independently represents an alkyl group having 1 to 3 carbon atoms. na represents the integer of 1-4 and 2 or 3 is preferable.

The alkyl group having 1 to 3 carbon atoms represented by R ²¹ and R ²² may be linear or branched, and examples thereof include a methyl group, an ethyl group, and a propyl group.

Specific examples of the polyoxyethylene glycol dialkyl ether represented by the general formula (α) include diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol diethyl ether, tetraethylene glycol diethyl ether, Examples include diethylene glycol ethyl methyl ether, triethylene glycol ethyl methyl ether, tetraethylene glycol ethyl methyl ether, diethylene glycol-di-n-propyl ether, and diethylene glycol-di-iso-propyl ether. Among these, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and diethylene glycol ethyl methyl ether are preferable.
Specific examples of the polyoxypropylene glycol dialkyl ether represented by the general formula (α) include propylene glycol dimethyl ether, propylene glycol diethyl ether, and dipropylene glycol dimethyl ether.

  Examples of preferable organic solvents include polyoxyethylene glycol monoalkyl ether and polyoxypropylene glycol monoalkyl ether. Specifically, polyoxyethylene glycol monoalkyl ether represented by the following general formula (β) and / or polyoxypropylene glycol monoalkyl ether represented by the following general formula (γ) are preferable.

^{_{R 31 - (OC 2 H 4}} ) nb -OH ··· formula (beta)
^{_{R 41 - (OC 3 H 6}} ) nc -OH ··· formula (gamma)

In the general formula (β), R ³¹ represents an alkyl group having 1 to 6 carbon atoms, and nb represents an integer of 1 to 6. R ³¹ may be linear or branched. Among the alkyl groups having 1 to 6 carbon atoms represented by R ³¹ , an alkyl group having 1 to 4 carbon atoms is preferable, and for example, a methyl group, an ethyl group, a propyl group, and a butyl group are preferable. Examples of the polyoxyethylene glycol monoalkyl ether represented by the general formula (β) include triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monobutyl ether, and pentaethylene glycol monomethyl ether. And hexaethylene glycol monomethyl ether.

In the general formula (γ), R ⁴¹ represents an alkyl group having 1 to 4 carbon atoms, and nc represents 2 or 3. R ⁴¹ may be linear or branched. Among the alkyl groups having 1 to 4 carbon atoms represented by R ⁴¹ , for example, a methyl group, an ethyl group, a propyl group, and a butyl group are preferable.
Examples of the polyoxypropylene glycol monoalkyl ether represented by the general formula (γ) include polypropylene glycol monoalkyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monopropyl ether, and dipropylene glycol. Examples include monobutyl ether and tripropylene glycol monomethyl ether.

In addition to the above, (poly) alkylene glycol monoalkyl ether monoalkyl ester compounds may be mentioned. Specifically, diethylene glycol monomethyl ether monomethyl ester, diethylene glycol monoethyl ether monomethyl ester, diethylene glycol monomethyl ether monoethyl ester, diethylene glycol monomethyl ether monobutyl ester, diethylene glycol monobutyl ether monomethyl ester, diethylene glycol monobutyl ether monoethyl ester, dipropylene glycol monomethyl ether Monomethyl ester, dipropylene glycol monoethyl ether monomethyl ester, dipropylene glycol monobutyl ether monomethyl ester, dipropylene glycol monoethyl ether monoethyl ester, dipropylene glycol monoethyl ether monobutyl ester, trie Ren glycol monomethyl ether monomethyl ester, triethylene glycol monoethyl ether monomethyl ester, triethylene glycol monobutyl ether monomethyl ester, tetraethylene glycol monomethyl ether monomethyl ester, tetraethylene glycol monoethyl ether monomethyl ester, tetraethylene glycol monobutyl ether monomethyl ester, etc. Illustrated.
Of these, di- or tripropylene glycol-based compounds are preferable in terms of higher safety compared to di- or triethylene glycol-based compounds, and are particularly suitable as organic solvents in inks.

The compound represented by the general formula (α) is preferably a compound having a boiling point of 150 ° C. or higher under atmospheric pressure, and more preferably a compound having a boiling point of 180 ° C. or higher under atmospheric pressure. The upper limit is not particularly limited, but is preferably a compound having a boiling point of 240 ° C. or lower under atmospheric pressure for the purpose of ink jet recording. Further, the density at 20 ° C. is preferably 0.9 g / cm ³ or more.

The compound represented by the general formula (β) is preferably a compound having a boiling point of 200 to 305 ° C. under atmospheric pressure and a boiling point of 240 to 305 ° C. under atmospheric pressure from the viewpoint of imparting volatilization inhibition to the ink. Is more preferable.
The compound represented by the general formula (γ) is preferably a compound having a boiling point of 170 to 245 ° C. under atmospheric pressure and a boiling point of 180 to 240 ° C. under atmospheric pressure from the viewpoint of imparting volatilization inhibition to the ink. Is more preferable.

  Among the glycol ether compounds, diethylene glycol diethyl ether and triethylene glycol diethyl ether among the compounds represented by the general formula (α) are more preferable, and dipropylene among the compounds represented by the general formula (β) or (γ). Glycol monomethyl ether and triethylene glycol monomethyl ether are preferred.

  The ink composition of the present invention preferably contains at least one organic solvent selected from the group consisting of the following general formulas (3) and (4), more preferably an organic solvent represented by the following general formula (3). preferable.

  First, the organic solvent represented by the general formula (3) will be described.

In General Formula (3), R ² and R ³ each independently represent —C (Rx) (Ry) —, —NR ⁵ —, or —O—. However, R ² and R ³ are not simultaneously —C (Rx) (Ry). Here, Rx and Ry each independently represent a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and R ⁵ represents a hydrogen atom, a hydroxy group, an alkyl group having 1 to 3 carbon atoms, or a hydroxyalkyl having 1 to 3 carbon atoms. Represents a group. R ⁴ is _{-C m H 2m -, - C} m H 2m-2 - , or _-C m _{H 2m-4} - represents a hydrocarbon group represented, m is an integer of 2-8.

Examples of the alkyl group in Rx and Ry include a methyl group, an ethyl group, an n-propyl group, and an isopropyl group.
Of Rx and Ry, both are hydrogen atoms, or one is a hydrogen atom and the other is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably both are hydrogen atoms.

R ⁵ is preferably a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a hydroxyalkyl group having 1 to 3 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. Note that the alkyl group of R ⁵ may be substituted with a substituent other than a hydroxy group.

Among R ² and R ³ , at least one is preferably —O— or —NR ⁵ —, one is —O— and the other is —C (Rx) (Ry) —, or one is —NR ⁵ —. The other is more preferably -C (Rx) (Ry)-, one is -O- and the other is particularly preferably -C (Rx) (Ry). Moreover, the case where both are -O- is also preferable.
When R ² and R ³ are both —O—, the organic solvent represented by the general formula (3) is a cyclic carbonate compound.

M in R ⁴ is preferably an integer of 2 to 6, more preferably an integer of 2 to 4, and still more preferably 2 or 3.
The hydrocarbon group for R ⁴ may be linear or branched.
R ⁴ is _-C m _{H 2m} - or _-C m _{H 2m-2} - are _preferred, -C _{m H 2m} - are more preferred.
Specific examples of R ⁴ are preferably an ethylene group, a 1-methylethylene group, a 2-methylethylene group, and a propylene group (trimethylene group). Of these, an ethylene group, a 1-methylethylene group, and a 2-methylethylene group are particularly preferable.

The organic solvent represented by the general formula (3) is a cyclic carbonate compound, a cyclic urea compound (preferably a 2-imidazolidinone compound), a cyclic urethane compound (preferably a 2-oxazolidinone compound), a cyclic amide compound, or a cyclic ester. Compounds, cyclic carbonate compounds, cyclic urea compounds and cyclic urethane compounds are preferred, and cyclic ester compounds are particularly preferred.
Specific examples of the organic solvent represented by the general formula (3) include ethylene carbonate, propylene carbonate, 3-methyl-2-oxazolidinone, 3-ethyl-2-oxazolidinone, 3-propyl-2-oxazolidinone, 1, 3 -Dimethyl-2-imidazolidinone, 2-pyrrolidone, 1-methyl-2-pyrrolidone, γ-butyrolactone, α-methyl-γ-butyrolactone, α, α-dimethyl-γ-butyrolactone, β-methyl-γ-butyrolactone , Γ-valerolactone and the like. However, the present invention is not limited to these.

  Next, the organic solvent represented by the general formula (4) will be described.

In General Formula (4), R ⁶ represents —NR ⁸ — or —O—. Here, R ⁸ represents a hydrogen atom, a hydroxy group, an alkyl group having 1 to 3 carbon atoms, or a hydroxyalkyl group having 1 to 3 carbon atoms. R ⁷ is _{-C n H 2n -, - C} n H 2n-2 - or _-C n _{H 2n-4} - represents a hydrocarbon group represented, n represents an integer of 2-8.

R ⁸ has the same meaning as R ⁵ in formula (3), and the preferred range is also the same.
R ⁶ is preferably —NR ⁸ —.
R ⁷ is _{-C n H 2n -, - C} n H 2n-2 - or _-C n _{H 2n-4} - represents a hydrocarbon group represented by, n is an integer of 2-8, the general formula (3) in the _-C m _H in _{^{R 4 2m -, - C m}} H 2m-2 - , or _-C m _{H 2m-4} - has the same meaning as the hydrocarbon group represented by, and the preferred range is also the same.

  Specific examples of the organic solvent represented by the general formula (4) include succinimide compounds such as N-ethylsuccinimide, glutaric anhydride, 3-methylglutaric anhydride, and the like. However, the present invention is not limited to these.

  By containing the organic solvent represented by the general formula (3) or (4), especially the organic solvent represented by the general formula (3), an ink composition excellent in ejection property, solvent resistance and adhesion Can be obtained.

  In addition to the above, triethyl citrate can also be used as a preferred organic solvent in terms of imparting volatilization inhibiting properties to the ink.

The total content of the organic solvent in the ink composition of the present invention (preferably an ink composition for inkjet recording) is preferably 50% by mass or more, and more preferably 70% by mass or more. The upper limit is preferably 99.95% by mass, and more preferably 98% by mass.
When the proportion of the organic solvent is within this range, the adhesion of the image formed by the ink composition of the present invention to the substrate is improved.

(Hydrocarbon solvent)
Examples of other organic solvents that can be contained in the ink composition of the present invention include hydrocarbon solvents. When using a hydrocarbon solvent, 1 mass%-30 mass% are preferable with respect to all the organic solvents, and 3 mass%-20 mass% are more preferable.

  A hydrocarbon solvent is a compound composed of only carbon and hydrogen atoms, usually a distillate from a natural or synthetic hydrocarbon mixture consisting of a single component or mixture, depending on its molecular structure, alkane, Alkenes, alkynes, cycloalkanes, aromatic hydrocarbons and the like are included. Examples of such hydrocarbon solvents include paraffins such as normal paraffin and isoparaffin, naphthene, paraffin and naphthene mixed solvents. The property of the hydrocarbon solvent may be fluid or solid. Among these, isoparaffinic solvents, normal paraffinic solvents, liquid paraffinic solvents, paraffin and naphthene mixed solvents are preferable, and these are readily available as commercial products.

In the present invention, it is preferable to use a plurality of organic solvents in combination, and it is preferable to use a ketone compound and / or an organic solvent represented by the general formula (3) in combination.
In this case, the organic solvent represented by the general formula (3) is preferably the above cyclic ester compound or cyclic amide compound, and it is also preferable to further use the cyclic ester compound and the cyclic amide compound together.
In the total mass of the organic solvent, the ketone compound is preferably 10% by mass to 80% by mass, more preferably 25 to 75% by mass, and further preferably 25% by mass to 50% by mass. In this case, the remainder is preferably an organic solvent represented by the general formula (3). Moreover, 0-30 mass parts is preferable with respect to 100 mass parts of cyclic ester compounds.

  In the present invention, a reactive diluent can also be used as the organic solvent. When a reactive diluent is used, the ink composition is preferably an active energy ray-curable ink composition to which a photopolymerization initiator described later is added. For example, an active energy ray such as a UV curable ink jet printer is used. It is preferable to perform printing with a printing machine equipped with an apparatus for irradiating the light. By using an active energy ray-curable ink composition, it is possible to obtain a curable composition that is more excellent in abrasion resistance and blocking resistance.

  As the reactive diluent, a polymerizable monomer can be used, and examples of the polymerization method include known polymerization methods such as radical polymerization, cationic polymerization, and anionic polymerization. Among these, radical polymerizable compounds are preferably used. The reactive diluent can be used alone or in combination. The reactive diluent may be a monofunctional compound or a polyfunctional compound. When the proportion of the monofunctional compound is large, the cured product tends to be flexible, and when the proportion of the polyfunctional compound is large, the curability tends to be excellent. Accordingly, the ratio between the monofunctional compound and the polyfunctional compound is arbitrarily determined according to the application.

As the reactive diluent, for example, various known radical polymerizable monomers that cause a polymerization reaction by an initiation species generated from a photo radical initiator can also be used.
Examples of the radical polymerizable monomer include vinyl compounds such as (meth) acrylate compounds, (meth) acrylamide compounds, aromatic vinyl compounds, N-vinyl compounds, and vinyl ethers.

Examples of these include (meth) acrylate compounds, (meth) acrylamide compounds, vinyl ether compounds, styrene compounds, N-vinyl compounds and the like described in JP-A-2008-208190 and 2008-266561. It is done.
Among these, in the present invention, it is preferable to use one or more monomers selected from a (meth) acrylate compound, a (meth) acrylamide compound, and a vinyl ether compound as the radical polymerizable monomer.

  Examples of the cationic polymerizable monomer include JP-A Nos. 6-9714, 2001-220526, 2001-40068, 2001-55507, 2001-310937, and 2001-310938. No. 2001, No. 2001-310937, No. 2001-220526, No. 2001-31892, No. 2003-341217, No. 2008-266561, etc. Compounds, oxetane compounds and the like.

  In the ink composition of the present invention, only one type of polymerizable monomer may be used, or two or more types may be used in combination, but two or more types may be used from the viewpoint of adjusting the curing sensitivity of the ink and the physical properties of the cured film. These polymerizable compounds are preferably used in combination. It is also preferable to use a polyfunctional polymerizable monomer having a plurality of polymerizable functional groups and a monofunctional polymerizable monomer in view of curing speed, viscosity of the ink composition, and film physical properties of the print sample.

  When a reactive diluent is used, the content of the reactive diluent in the ink composition of the present invention is preferably 50% by mass to 95% by mass, more preferably 70% by mass to the total amount of the ink composition. 92% by mass.

  A reactive diluent may be used in combination with another organic solvent. When the reactive diluent and the organic solvent are used in combination, the reactive diluent is preferably 2% by mass to 50% by mass, more preferably 2% by mass to 40% by mass with respect to the total amount of the ink composition. .

It is preferable to use a polymerization initiator in combination with the non-aqueous ink composition of the present invention from the viewpoint of improving the curing sensitivity.
<Polymerization initiator>
The non-aqueous ink composition of the present invention preferably contains a polymerization initiator for radical polymerization or cationic polymerization, and more preferably contains a photopolymerization initiator.
The photopolymerization initiator in the present invention is a compound that undergoes a chemical change through the action of an active energy ray or interaction with the electronically excited state of a sensitizing dye, and generates at least one of radicals, acids, and bases. It is.

  The photopolymerization initiator is an active energy ray to be irradiated, for example, ultraviolet rays having a wavelength of 200 to 400 nm, far ultraviolet rays, g rays, h rays, i rays, KrF excimer laser rays, ArF excimer laser rays, electron rays, X rays. Those having sensitivity to a molecular beam or an ion beam can be appropriately selected and used.

  As the photopolymerization initiator, those known to those skilled in the art can be used without limitation, and for example, the photopolymerization initiators described in JP-A-2008-208190 and 2008-266561 can be used, and aromatics can be used. Ketones, aromatic onium salt compounds, organic peroxides, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon halogen bond, etc. are preferred. Particularly preferred are aromatic ketones, ketoxime salt compounds, and aromatic onium salt compounds.

  The photoinitiator as a polymerization initiator can be used individually by 1 type or in combination of 2 or more types. The content of the photopolymerization initiator in the ink composition is preferably in the range of 1 to 20% by mass, more preferably 3 to 15% by mass with respect to the mass of the reactive diluent. It is particularly preferably 10 to 10% by mass.

  In the ink composition of the present invention, various additives such as a sensitizing dye and a co-sensitizer can be further used depending on the purpose. As the sensitizing dye, for example, sensitizing dyes described in paragraph Nos. 0228 to 0237 of JP 2010-13630 A can be preferably used. Examples of the co-sensitizer include the co-sensitizers described in paragraph numbers 0238 to 0240 of JP 2010-13630 A.

  When a reactive diluent is used, a polymerization inhibitor may be added to the ink composition of the present invention. Polymerization inhibitors include phenolic hydroxyl group-containing compounds, quinones, N-oxide compounds, piperidine-1-oxyl free radical compounds, pyrrolidine-1-oxyl free radical compounds, N-nitrosophenylhydroxylamines, And a compound selected from the group consisting of cationic dyes. As content in the ink composition of a polymerization inhibitor, 1000-20000 ppm is preferable with respect to the total mass of an ink composition, 2000-17000 ppm is more preferable, 4000-15000 ppm is more preferable.

(Other ingredients)
The non-aqueous ink composition of the present invention includes a polymer binder, a surfactant, and a surface condition as necessary, in addition to the above-described polymeric fluorescent dye, organic solvent and various additives, as long as the effects of the present invention are not impaired. Agents, leveling agents, antifoaming agents, antioxidants, pH adjusting agents, charge imparting agents, bactericides, antiseptics, deodorants, charge adjusting agents, wetting agents, anti-skinning agents, perfumes, pigment derivatives, etc. An additive may be added as an optional component.

(Polymer binder)
The ink composition of the present invention may further contain a polymer binder. The polymer binder is not limited as long as it is a polymer compound that can be dissolved in the ink composition and develops film properties after image formation. Specific examples include polyacrylate, polyurethane, polyester, polyether, and the like. As the polymer binder, it is preferable to use a polyacrylate or the like which is an alkyl (meth) acrylate homopolymer or copolymer. From the viewpoint of adjusting the physical properties of the ink film after image formation, the ink composition of the present invention preferably contains a polymer binder.

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

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

<Image forming method>
The image forming method of the present invention includes an ink applying step of applying the non-aqueous ink composition of the present invention onto a recording medium, and a step of drying the non-aqueous ink composition applied onto the recording medium. By performing these steps, an image of the ink composition fixed on the recording medium is formed.

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

  The ink jet recording apparatus that can be used in the image forming method of the present invention is not particularly limited, and a known ink jet recording apparatus that can achieve the target resolution can be arbitrarily selected and used. That is, any known ink jet recording apparatus including a commercially available product can discharge the ink composition onto the recording medium in the ink jet recording method of the present invention.

Examples of the ink jet recording apparatus that can be used in the present invention include an apparatus including an ink supply system, a temperature sensor, and a heating unit.
The ink supply system includes, for example, an original tank containing the ink composition of the present invention, a supply pipe, an ink supply tank immediately before the inkjet head, a filter, and a piezo-type inkjet head. The piezo-type inkjet head preferably has a multi-size dot of 1 to 100 pl, more preferably 8 to 30 pl, preferably 320 × 320 to 4,000 × 4,000 dpi, more preferably 400 × 400 to 1,600 ×. It can be driven so that it can discharge at a resolution of 1,600 dpi, more preferably 720 × 720 dpi. In the present invention, dpi represents the number of dots per 2.54 cm.

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

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

  Viscosity fluctuation of the ink composition has a great influence on the change of the droplet size and the change of the droplet discharge speed, and thus causes the image quality deterioration. Therefore, it is necessary to keep the temperature of the ink composition during ejection as constant as possible. Therefore, in the present invention, the temperature control range of the ink composition is preferably set to ± 5 ° C. of the set temperature, more preferably ± 2 ° C. of the set temperature, and further preferably set temperature ± 1 ° C. .

  In the present invention, the recording medium is not particularly limited, and a known recording medium can be used as a support or a recording material. Examples of the recording medium include paper, paper laminated with plastic (eg, polyethylene, polypropylene, polystyrene, etc.), metal plate (eg, aluminum, zinc, copper, etc.), plastic film (eg, polyvinyl chloride resin, two Cellulose acetate, cellulose triacetate, cellulose propionate, cellulose butyrate, cellulose acetate butyrate, cellulose nitrate, polyethylene terephthalate, polyethylene, polystyrene, polypropylene, polycarbonate, polyvinyl acetal, etc.), paper or plastic on which the above metals are laminated or deposited A film etc. are mentioned. Among them, since the ink composition of the present invention has excellent adhesion, it can be suitably used as a recording medium for a non-absorbing (non-penetrable) recording medium. From the viewpoint of adhesion, polyvinyl chloride, polyethylene terephthalate. A plastic substrate such as polyethylene is preferable, a polyvinyl chloride resin substrate is more preferable, and a polyvinyl chloride resin sheet or film is more preferable.

(Drying process)
The ink composition applied on the recording medium is preferably fixed by evaporating the solvent component by the heating means. A process of applying heat to the applied ink composition of the present invention for fixing will be described.
The heating means is not limited as long as the organic solvent can be dried, and a heat drum, hot air, an infrared lamp, a heat oven, a heat plate heating, or the like can be used.
The heating temperature is not particularly limited as long as the organic solvent present in the ink composition evaporates and the polymer fluorescent dye can form a film of a polymer binder to be added as necessary. If it is, the effect will be acquired and about 40 to 150 degreeC is preferable, More preferably, it is about 40 to 80 degreeC. If the temperature exceeds 100 ° C., the recording medium may be deformed and the like may cause problems in conveyance.
The heating time in the drying step is not particularly limited as long as the organic solvent present in the ink composition evaporates and a film of the resin agent can be formed, taking into account the composition and printing speed of the ink composition to be used. Can be set as appropriate.

(Printed matter)
The printed matter of the present invention has an image formed by applying the non-aqueous ink composition of the present invention or recorded by an image forming method. The printed matter of the present invention is a printed matter excellent in the solvent resistance of the recorded image and the adhesion to the substrate.

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

  The ink compositions used in Examples and Comparative Examples are shown below.

<Preparation of polymeric fluorescent dye>
(Synthesis of monomer A-1 having a fluorescent dye moiety in the repeating unit)
Monomer A-1 was synthesized as follows.

  9 (10H) acridone [Wako Pure Chemical Industries, Ltd.] 15 g and sodium hydroxide [Wako Pure Chemical Industries, Ltd.] 3.4 g were dissolved in 84 g of dimethyl sulfoxide [Wako Pure Chemical Industries, Ltd.] 84 g. And heated to 45 ° C. To this solution, 17.6 g of CMS-P (chloromethylstyrene, manufactured by Seimi Chemical Co., Ltd.) was added dropwise, and the mixture was further heated and stirred at 50 ° C. for 5 hours. This reaction solution was poured into a mixed solution of 30 g of distilled water and 30 g of methanol [manufactured by Wako Pure Chemical Industries, Ltd.] with stirring. The precipitate in the mixed solution was filtered off and washed with 300 g of a solution in which distilled water and methanol were mixed in the same mass. This precipitate was monomer A-1, and the yield was 17.5 g.

(Synthesis Example 1: Synthesis of polymeric fluorescent dye P-1)
Polymer fluorescent dye P-1 was synthesized as follows.

  In a 300 ml three-necked flask equipped with a stirrer and a condenser tube, 81.0 g (0.81 mol) of methyl methacrylate [manufactured by Wako Pure Chemical Industries, Ltd.] and 9.0 g (0.029 mol) of monomer A-1 And 126 g of methyl ethyl ketone (manufactured by Wako Pure Chemical Industries, Ltd.) were added and heated to 75 ° C. in a nitrogen atmosphere. Thereto, 1.20 g of dimethyl 2,2′-azobisisobutyrate [V-601, manufactured by Wako Pure Chemical Industries, Ltd.] dissolved in 8 g of methyl ethyl ketone was added and reacted for 2 hours. 0.50 g of dimethyl 2,2′-azobisisobutyrate dissolved in 6 g was added and reacted for 2 hours. Further, 0.50 g of dimethyl 2,2′-azobisisobutyrate dissolved in 0.6 g of methyl ethyl ketone was added, the temperature was raised to 80 ° C., and the mixture was heated and stirred for 4 hours to react all unreacted monomers. By adding methyl ethyl ketone to the solution after completion of the reaction and adjusting the concentration to 40% by mass, a polymer fluorescent dye solution (P-1) containing 40% by mass of polymer P-1 was obtained.

The composition of the obtained polymer was confirmed by ¹ H-NMR. The weight average molecular weight (Mw) determined by GPC was 35,000. The weight average molecular weight (Mw) was detected using a solvent THF and a differential refractometer with a GPC analyzer in which columns of TSKgel GMHxL, TSKgel G4000HxL, and TSKgel G2000HxL (all trade names of Tosoh Corporation) were connected in series. And obtained using polystyrene as a standard substance.
Moreover, the glass transition temperature of the obtained polymer was 105 degreeC as a result of measuring by Seiko Instruments Co., Ltd. DSC-6220.

(Synthesis Example 2: Synthesis of polymeric fluorescent dye P-2)
Polymer fluorescent dye P-2 was synthesized as follows.

  Synthesis example except that n-butyl methacrylate (manufactured by Wako Pure Chemical Industries, Ltd.) and methyl methacrylate were used instead of methyl methacrylate and the monomer amount was adjusted so that the mass ratio of P-2 was obtained. In the same manner as in Example 1, polymeric fluorescent dye P-2 (polymer P-2) was synthesized. The thus obtained polymeric fluorescent dye P-2 had a glass transition temperature of 35 ° C. and a weight average molecular weight (Mw) of 38,000.

(Synthesis Example 3: Synthesis of polymeric fluorescent dye P-3)
Polymer fluorescent dye P-3 was synthesized as follows.

  Synthesis example except that n-butyl methacrylate and tetrahydrofurfuryl methacrylate [manufactured by Tokyo Chemical Industry Co., Ltd.] were used instead of methyl methacrylate, and the monomer amount was adjusted so that the mass ratio of P-3 was obtained. In the same manner as in Example 1, polymeric fluorescent dye P-3 (polymer P-3) was synthesized. The thus obtained polymeric fluorescent dye P-3 had a glass transition temperature of 52 ° C. and a weight average molecular weight (Mw) of 42,000.

(Synthesis Example 4: Synthesis of polymeric fluorescent dye P-4)
Polymer fluorescent dye P-4 was synthesized as follows.

  The amount of methyl methacrylate and monomer A-1 is adjusted so that the mass ratio of P-4 can be obtained, and each amount of dimethyl 2,2′-azobisisobutyrate added multiple times is adjusted. A polymeric fluorescent dye P-4 (polymer P-4) was synthesized in the same manner as in Synthesis Example 1 except that 0.12 g was used. The thus obtained polymeric fluorescent dye P-4 had a glass transition temperature of 110 ° C. and a weight average molecular weight (Mw) of 90,000.

<Preparation of ink composition>
The raw materials described were mixed and stirred at 500 rpm using a mixer (Silverson L4R) so that the ratios shown in Table 1 below were obtained, to obtain an ink composition. Each of these was packed in a plastic disposable syringe and filtered through a polyvinylidene fluoride (PVDF) pore size 5 μm filter (Millipore Millex-SV, diameter 25 mm). Examples 1 to 11 and Comparative Examples 1 to 1 3 ink compositions were obtained.

In Table 1, BL represents γ-butyrolactone (manufactured by Wako Pure Chemical Industries, Ltd.), and MEK represents methyl ethyl ketone (manufactured by Wako Pure Chemical Industries, Ltd.). 2-Pyrrolidone manufactured by Wako Pure Chemical Industries, Ltd. was used. DEGDE indicates diethylene glycol diethyl ether [manufactured by Tokyo Chemical Industry Co., Ltd.]. In Table 1, PVC indicates that a polyvinyl chloride substrate was used.
The viscosity of the obtained ink composition is in the range of 3 to 8 mPa · s at room temperature, 10 mg of the ink solution is measured, and the visible light wavelength region (380 nm to 380 nm) of the solution made up to 20 ml with the same solvent composition is used. (780 nm) was less than 0.2 (measured using Shimadzu Corporation, UV-2550). Moreover, the particle size of the ink of the example was not observed with a dynamic light scattering measurement apparatus (FPAR-1000, manufactured by Otsuka Electronics Co., Ltd.).

<Evaluation of ink composition>
Each of the obtained ink compositions was printed on an 8 cm square plain paper [manufactured by Nippon Paper Industries Co., Ltd., trade name: Shiraoi, paper thickness 149 μm, using a K hand coater (bar No. 2) manufactured by RK PRINT COAT INSTRUMENTS. Then, a solid image (predetermined density image) was formed by coating a polyvinyl chloride substrate (Avery Dennison, AVERY 400 GLOSS WHITE PERMANENT, paper thickness 90 μm) with a thickness of 12 μm. Then, the water | moisture content was dried for 3 minutes at 60 degreeC.
Each ink composition was diluted 10 times with MEK (methyl ethyl ketone) to prepare a sample having a concentration of 1/10. Next, a solid image (1/10 density image) was formed using the sample by the same method as the formation of the solid image. Of the following evaluations, evaluations other than the density evaluation were performed without diluting each ink composition.

<Concentration>
The obtained predetermined density image and 1/10 density image were irradiated with a low-pressure mercury lamp, and the emission intensity was visually evaluated according to the following evaluation criteria.

Evaluation Criteria A: Sufficient blue light emission is observed in both the predetermined density image and the 1/10 density image B: The blue light emission is sufficiently observed in the predetermined density image, but the 1/10 density image is blue C: Slight blue emission even in the predetermined density image

<Glossy evaluation>
The glossiness of the image was evaluated by measuring the glossiness under the following conditions.
The prepared solid image and support were measured at a measurement angle of 60 ° using a gloss meter manufactured by Sheen Instruments, based on JIS Z8741. Evaluation was performed according to the following evaluation criteria. The evaluation B or higher is a practically acceptable level.

Evaluation criteria A: The difference in glossiness between the support and the printed part is -5 or more and 5 or less B: The difference in glossiness between the support and the printed part is -10 or more and less than -5, or more than 5 and 10 or less It is.
C: The difference in glossiness between the support and the printed part is less than −10 or more than 10.

<Blocking resistance evaluation>
The obtained two printed materials were overlapped so that the printed screens matched each other, and further pressurized at 30 ° C. for 1 hour at a pressure of 1 kg / cm ² . Thereafter, the two printed materials were peeled off, and the state of the image was observed while irradiating with a low-pressure mercury lamp. The following evaluation criteria were used for visual evaluation.

Evaluation criteria A: No peeling of the image and no sound when peeling the printed material B: No peeling of the image, but no sound when peeling the printed material C: No peeling of the image, but some images D: Image peeling occurs

<Evaluation of substrate adhesion>
As a method for evaluating the adhesion between the image and the substrate made of polyvinyl chloride, a cross hatch test (JIS K5600-5-6, 2004) was performed on the obtained solid image (predetermined density image). In addition, evaluation of base-material adhesiveness was evaluated in six steps of classification 0 to classification 5 according to JIS K5600-5-6 (2004). Here, the classification 0 means that the edge of the cut is completely smooth and there is no peeling in the eyes of any lattice.
The cross-hatch test was evaluated by cutting from the image to the depth reaching the substrate. The following evaluations A and B have no practical problem.

Evaluation criteria A: Classification 0 or 1 in JIS K5600-5-6 (2004)
B: Classification 2 or 3 in JIS K5600-5-6 (2004)
C: Classification 4 or 5 in JIS K5600-5-6 (2004)

<Bleeding evaluation>
As an ink jet recording apparatus, a commercially available ink jet printer (DMP-2831 manufactured by Fuji Film Dimatics) was prepared. The obtained ink composition was loaded into the inkjet printer and heated at 40 ° C. (Shiraoi, paper thickness 149 μm) and a polyvinyl chloride substrate (Avery Dennison, AVERY 400 GLOSS WHITE PERMANENT) Two thin lines having a width of 1 mm and a length of 5 cm were recorded in parallel at intervals of 0.5 mm on a paper thickness of 90 μm. After the discharge was stopped, the obtained fine line was visually evaluated according to the following evaluation criteria while being irradiated with a low-pressure mercury lamp.
Evaluation criteria A: A state in which there is almost no blur and the fine line is a straight line. B: A slight blur is present, but the fine line is almost a straight line and there is no problem in practical use. C: A part of the fine line becomes thick due to the blur. Combined and practically problematic

<Abrasion resistance>
The image of the fine line image obtained in the bleedability evaluation test was rubbed with a cotton swab 5 times in the minor axis direction of the fine line. evaluated.
Evaluation criteria A: No damage to the image and no transfer to the swab B: No damage to the image and transfer to the swab C: Damage to the image and transfer to the swab

<Image uniformity>
The image uniformity of a solid image having a normal density (predetermined density image) used in the density evaluation was evaluated based on the following criteria by visual inspection for color unevenness.

Evaluation criteria A: The image is uniform B: Unevenness occurs in part of the image, but there is no practical problem C: Unevenness occurs in the entire image, and there is a practical problem

  The results are summarized in Table 1.

As can be seen from Table 1, the ink composition of the present invention was as good as B or more in all evaluation items. Examples 1 to 9 using the polymeric fluorescent dye of the present invention are non-permeable substrates made of polyvinyl chloride compared to Comparative Examples 1 and 2 using monomer A-1 as the fluorescent dye. The substrate adhesion to the substrate is good.

The above problem has been solved by the following means.
<1> contains an ink-soluble polymer fluorescent dye having a fluorescent site in the repeating unit and an organic solvent , and does not substantially absorb visible light ; and
A non-aqueous ink composition in which the polymeric fluorescent dye has a repeating unit represented by the following general formula (1) .

In General Formula (1), R ¹ represents a hydrogen atom or a methyl group, and X represents a phenylene group, —COO—, or —CONR ² —. Here, R ² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y represents a single bond or a linear or branched alkylene group having 1 to 8 carbon atoms. In the alkylene group, —O—, —OC (═O) —, —CH (OH) —, —NH—, Alternatively, -NHC (= O)-may be included. Z represents a fluorescent dye residue.
<2> The non-aqueous ink composition according to <1>, wherein the glass transition temperature of the polymeric fluorescent dye is 40 ° C. or higher.
<3> The nonaqueous ink according to <1> or <2>, wherein the content of the polymeric fluorescent dye is 0.5% by mass or more and 5.0% by mass or less with respect to the total mass of the nonaqueous ink composition. Composition.
<4> The content of the repeating unit represented by formula in the polymeric fluorescent dye (1) is, relative to the total weight of the polymeric fluorescent dye, not more than 30 mass% to 5 mass% <1> to <3> The non-aqueous ink composition according to any one of 3> .
< 5 > The non-aqueous ink composition according to any one of <1> to < 4 >, which is for inkjet.
< 6 > An ink application step of applying the nonaqueous ink composition according to any one of <1> to < 5 > onto a recording medium, and drying the nonaqueous ink composition applied onto the recording medium. And an image forming method .

Claims (9)

  A non-aqueous ink composition that contains an ink-soluble polymer fluorescent dye having a site that emits fluorescence in a repeating unit, and an organic solvent, and does not substantially absorb visible light.   The non-aqueous ink composition according to claim 1, wherein the polymeric fluorescent dye has a glass transition temperature of 40 ° C. or higher.   3. The non-aqueous ink composition according to claim 1, wherein the content of the polymeric fluorescent dye is 0.5% by mass or more and 5.0% by mass or less with respect to the total mass of the non-aqueous ink composition. The non-aqueous ink composition according to claim 1, wherein the polymeric fluorescent dye has a repeating unit represented by the following general formula (1).

In General Formula (1), R ¹ represents a hydrogen atom or a methyl group, and X represents a phenylene group, —COO—, or —CONR ² —. Here, R ² represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y represents a single bond or a linear or branched alkylene group having 1 to 8 carbon atoms, and in the alkylene group, —O—, —OC (═O) —, —CH (OH) —, —NH— , Or -NHC (= O)-may be contained. Z represents a fluorescent dye residue.   The content of the repeating unit represented by the general formula (1) in the polymer fluorescent dye is 5% by mass or more and 30% by mass or less with respect to the total mass of the polymer fluorescent dye. Non-aqueous ink composition.   The non-aqueous ink composition according to claim 1, which is for inkjet. An ink application step of applying the non-aqueous ink composition according to any one of claims 1 to 6 onto a recording medium;
And a step of drying the non-aqueous ink composition applied on the recording medium.   A printed matter formed by applying the non-aqueous ink composition according to any one of claims 1 to 6 on a recording medium. A printed matter having an image recorded by the image forming method according to claim 7.