JP2016121225A - Ink composition, ink set, and image formation method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition that enables recording with excellent color development and reduced setoff by means of an inkjet recording device.SOLUTION: An ink composition according to the present invention comprises an organic solvent with a 50% distillation point of 300°C or higher and an iodine value of 100 or more, a polymerization initiator, and a colorant.SELECTED DRAWING: None

Description

  The present invention relates to an ink composition, an ink set, and an image forming method.

  Conventionally, a printing method using an ink jet recording method is performed by causing ink droplets to fly and adhere to a recording medium such as paper. In addition, due to recent advances in ink jet recording system technology, ink jet recording apparatuses using an ink jet recording system are also being used in the field of high-definition image recording (image printing), which previously used photography and offset printing. Yes.

  In inkjet recording, various types of ink are used depending on the type and purpose of the recording medium. Examples of the ink include water-based inks mainly containing water, oil-based inks mainly containing organic solvents (non-aqueous solvents), and curable inks mainly containing polymerizable compounds. As an example, Patent Document 1 discloses an inkjet ink in which a pigment and resin particles are blended in a non-aqueous medium. In Patent Document 1, after the ink is attached to a recording medium, the pigment is fixed to the recording medium with a resin by heating.

JP 2001-311023 A

  Non-aqueous (oil-based) inks adhere to a medium such as paper, and the organic compound used in the solvent tends to maintain fluidity. There was a case where it was swept away in an untouched area. For example, there is a case where a color material flows on the back surface of the recording surface of the recording medium and the set-off occurs.

  In the ink described in Patent Document 1, attempts are made to prevent the flow of the pigment by the resin particles. However, after the pigment and the resin particles are attached to the recording medium, the resin is melted in the recording medium, In this case, since the pigment is allowed to meet the resin and the resin is solidified, the movement of the pigment in the recording medium cannot always be prevented efficiently. In addition, the ink of the same document employs resin particles to fix the pigment, and there are certain restrictions on the selection of the type of resin particles, such as melting temperature, particle diameter, and blending amount.

  One of the objects according to some embodiments of the present invention is to provide an ink composition, an ink set, and an image forming method capable of recording with good color development and reduced set-off by an inkjet recording apparatus. It is in.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following aspects or application examples.

[Application Example 1] One aspect of the ink composition according to the present invention is an ink composition for inkjet recording,
An organic solvent having a 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher, a polymerization initiator, and a coloring material are included.

  Such an ink composition can polymerize (solidify) an organic solvent having a high iodine value (corresponding to a so-called semi-drying oil and / or drying oil) with a polymerization initiator. Thereby, it is possible to suppress the color material from moving in the recording medium, and it is possible to perform recording with good color development and reduced set-off.

[Application Example 2] In Application Example 1,
The organic solvent may be contained in an amount of 20% by mass or more.

  Since such an ink composition is more easily solidified, it is possible to perform recording with better color development and reduced set-off.

[Application Example 3] In Application Example 1 or Application Example 2,
The iodine value of the organic solvent may be 130 or more.

  Since such an ink composition is more easily solidified, it is possible to perform recording with better color development and reduced set-off.

[Application Example 4] In any one of Application Examples 1 to 3,
The organic solvent may be contained in an amount of 60% by mass or more.

  Since such an ink composition is more easily solidified, it is possible to perform recording with better color development and reduced set-off.

[Application Example 5] In any one of Application Examples 1 to 4,
The polymerization initiator may be an azo compound.

  Such an ink composition can easily perform the polymerization (solidification) of the organic solvent, and can perform recording with good color development and reduced set-off.

Application Example 6 One aspect of the image forming method according to the present invention is as follows.
An image forming method using the ink composition according to any one of Application Examples 1 to 5,
Attaching the ink composition to a recording medium with an inkjet recording apparatus;
Heating the ink composition attached to the recording medium, or irradiating the ink composition attached to the recording medium with light;
including.

  According to such an image forming method, an organic solvent having a high iodine value (so-called semi-drying oil and / or drying oil) can be polymerized (solidified) by the polymerization initiator. Thereby, it is possible to suppress the movement of the color material in the recording medium, and it is possible to perform recording with good color development and reduced offset.

[Application Example 7] One aspect of the ink set according to the present invention is as follows.
A first liquid containing an organic solvent having a 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher, and a coloring material;
A second liquid containing the organic solvent and a polymerization initiator;
including.

According to such an ink set, the organic solvent having a large iodine value (so-called semi-drying oil and / or drying oil) contained in the first liquid is polymerized (solidified) by the polymerization initiator contained in the second liquid. Can do. Thereby, it is possible to suppress the movement of the color material in the recording medium, and it is possible to perform recording with good color development and reduced offset.

Application Example 8 One aspect of the image forming method according to the present invention is as follows.
An image forming method using the ink set according to Application Example 7,
Attaching the first liquid to a recording medium by an inkjet recording apparatus;
Attaching the second liquid to a recording medium with an inkjet recording apparatus;
including.

  If it does in this way, the organic solvent (what is called semi-drying oil and / or drying oil) with a large iodine number contained in the 1st liquid can be polymerized (solidified) with the polymerization initiator contained in the 2nd liquid. Thereby, it is possible to suppress the movement of the color material in the recording medium, and it is possible to perform recording with good color development and reduced offset.

[Application Example 9] In Application Example 8,
The step of attaching the first liquid and the step of attaching the second liquid may be performed in this order, the reverse order, or simultaneously.

[Application Example 10] In Application Example 8 or Application Example 9,
After the first liquid and the second liquid adhere to the recording medium, or at the same time as the first liquid and the second liquid adhere to the recording medium,
The method may include a step of heating the first liquid and the second liquid attached to the recording medium, or irradiating light to the first liquid and the second liquid attached to the recording medium.

  In this way, the organic solvent can be solidified more easily.

[Application Example 11] In any one of Application Examples 8 to 10,
Wherein the recording medium, wherein the first liquid is deposited amount of 7 mg / inch ² or more 15 mg / inch ² or less, the second liquid may be deposited in an amount of 7 mg / inch ² or more 15 mg / inch ² or less.

  Embodiments of the present invention will be described below. Embodiment described below demonstrates an example of this invention. In addition, the present invention is not limited to the following embodiments, and includes various modifications that are implemented within a range that does not change the gist of the present invention. Note that not all of the configurations described below are essential configurations of the present invention.

1. Ink composition The ink composition of this embodiment contains an organic solvent, a polymerization initiator, and a coloring material. The ink composition of the present embodiment is an ink composition for inkjet recording.

1.1. Organic Solvent The ink composition of the present embodiment includes an organic solvent having a 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher.

Organic solvents with a 50% distillation point of 300 ° C or higher include linseed oil, tung oil, soybean oil, soybean oil methyl, soybean oil isobutyl, rapeseed oil, ethyl oleate, isostearyl alcohol, oleyl alcohol, isopalmitic acid, isostearic acid , Isoarachidic acid, isohexaconic acid, isopropyl isostearate, methyl linoleate, isobutyl linoleate, isobutyl tall oil and the like.

  The 50% distillation point is a value according to JIS K0066 “Method for Distillation Test of Chemical Products”. The 50% distillation point is, as a general rule, the temperature at which the container solvent evaporates at 50% under normal pressure. The amount of solvent evaporation is small. Therefore, the ink composition of the present embodiment is suppressed in evaporation of the organic solvent and has good storage stability. For example, drying at the nozzle of the ink jet recording apparatus is suppressed, and discharge stability is also improved.

  Examples of the organic solvent having an iodine value of 100 or more include organic solvents classified into so-called dry oil and semi-dry oil.

  The iodine value is an index indicating the amount of unsaturated bonds, and those having an iodine value of 130 or more are sometimes referred to as drying oils, and those having 100 or more and less than 130 are sometimes referred to as semi-drying oils. A dry oil is an oil that hardens when left in the air, and a semi-dry oil is an oil whose fluidity decreases when left in the air.

Organic solvents having an iodine value of 130 or more include linseed oil (180), tung oil (170), coconut oil, shiso oil, walnut oil, coconut oil, safflower oil, sunflower oil, soybean oil (133), and isobutyl soybean oil. (130) etc. can be illustrated. Corn oil as the organic solvent having an iodine value of less than 100 or more 130, cottonseed oil, sesame oil, soybean oil methyl (120), can be exemplified rapeseed (100) or the like (in parentheses, the value of an iodine value _(gI 2/100 g) is there.).

  The iodine value is a value according to JIS K0070 “Testing Method for Acid Value, Saponification Value, Ester Value, Iodine Value, Hydroxyl Value, and Unsaponified Product of Chemical Products”. The iodine value is a value obtained by converting the amount of halogen bonded to 100 g of sample into the number of g of iodine, and corresponds to the amount of unsaturated bonds (carbon-carbon double bonds) contained in the sample. To do.

  Organic solvents contained in the ink composition of the present embodiment having a 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher include linseed oil, tung oil, soybean oil, soybean oil isobutyl, Examples include soybean oil methyl and rapeseed oil.

  An organic solvent having a 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher can be used alone or in combination of two or more. If an organic solvent having a 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher is contained at least 10% by mass or more based on the total amount of the ink composition, an effect based on solidification can be obtained. However, when the content is 20% by mass or more, more preferably 40% by mass or more, and still more preferably 60% by mass or more, the organic solvent can be solidified more easily and the fluidity of the ink composition can be more easily suppressed. Become.

  The ink composition more preferably contains an organic solvent having a 50% distillation point of 300 ° C. or higher and an iodine value of 130 or higher. Examples of such organic solvents include linseed oil, tung oil, soybean oil, soybean oil isobutyl, and the like. When such an organic solvent is used, it is easier to solidify the organic solvent and it becomes easier to suppress the fluidity of the ink composition.

1.2. Polymerization initiator The ink composition of the present embodiment contains a polymerization initiator. The polymerization initiator can be used without limitation as long as it can generate radicals and active species of acids. The unsaturated bond of the organic solvent described above is polymerized by the active species generated by the polymerization initiator. As a result, the polymerization based on the double bond of the organic solvent can be started more reliably than by relying on oxygen in the atmosphere, and the viscosity of the ink composition can be quickly increased to suppress the flow of the ink composition. Can do.

  The method for generating the active species of the polymerization initiator may be either light (radiation) irradiation and / or heating. Hereinafter, the photopolymerization initiator and the thermal polymerization initiator will be described.

  As a photoinitiator, the substance which produces the active species which causes superposition | polymerization of an unsaturated bond by light can be mentioned. Examples of the photopolymerization initiator include benzophenone, benzoin, acetophenone, thioxanthone, alkylphenone, acylphosphine oxide titanocene, oxime ester, oxyphenylacetate, and cation. Also, triethanolamine, methyldiethanolamine, triisopropanolamine, 4,4-dimethylaminobenzophenone, ethyl 4,4-diethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate (n-butoxy) Initiators such as 2-ethylhexyl 4-dimethylaminobenzoate and triphenylamine may be used. Furthermore, conventionally known initiators such as aryl alkyl ketones, oxime ketones, S-phenyl thiobenzoate, titanocene, aromatic ketones, thioxanthones, benzylquinone derivatives, and ketocoumarins can be used.

  Specific examples of the photopolymerization initiator include acetophenone, 2,2-diethoxyacetophenone, p-dimethylaminoacetophenone, benzophenone, 2-chlorobenzophenone, p, p′-dichlorobenzophenone, p, p′-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-propyl ether, benzoin isobutyl ether, benzoin n-butyl ether, benzyl methyl ketal, 2,2-dimethoxy-1,2-diphenyl Ethan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) benzyl] phenyl 2-methylpropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1, 2-dimethylamino-2- (4-methylbenzyl) -1- (4- Morpholin-4-yl-phenyl) butan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6- Dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, 2-methyl-1- [4- (methylthio) phenyl] 2-morpholinopropan-1-one, thioxanthone, 2-chlorothioxanthone, 2-hydroxy 2-Methyl-1-phenyl-1-one, 1- (4-isopropylphenyl) -2- Dorokishi-2-methylpropan-1-one, methyl benzo fill formate, azo-bis-isobutyronitrile Lilo nitrile, benzoyl peroxide, di -tert- butyl peroxide, and the like.

Examples of commercially available photopolymerization initiators include IRGACURE 651 (2,2-dimethoxy-1,2-diphenylethane-1-one), IRGACURE 184 (1-hydroxy-cyclohexyl-phenyl-ketone), DAROCUR 1173 ( 2-hydroxy-2-methyl-1-phenyl-propan-1-one), IRGACURE 2959 (1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1 -One), IRGACURE 127 (2-hydroxy-1- {4- [4- (2-hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one), IRGACURE 907 ( 2-Methyl-1- (4-methylthiophenyl) -2-morpholinopropane -1-one), IRGACURE 369 (2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1), IRGACURE 379 (2- (dimethylamino) -2-[(4-methyl Phenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone), DAROCUR TPO (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide), IRGACURE 819 (bis (2,4 , 6-trimethylbenzoyl) -phenylphosphine oxide), IRGACURE 784 (bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) ) -Phenyl) titanium), IRGACURE OXE 01 (1.2-octa Dione, 1- [4- (phenylthio)-, 2- (O-benzoyloxime)]), IRGACURE OXE 02 (ethanone, 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3) -Yl]-, 1- (O-acetyloxime)), IRGACURE 754 (oxyphenylacetic acid, 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester and oxyphenylacetic acid, 2- (2-hydroxyethoxy) Ethyl ester mixture) (Ciba Japan KK), DETX-S (2,4-diethylthioxanthone) (Nippon Kayaku Co., Ltd.), Lucirin TPO , LR8883, LR8970 (above, manufactured by BASF) and Ubekrill P36 (manufactured by UCB).

  These radical photopolymerization initiators can be used alone or in combination of two or more. Some of the illustrated radical photopolymerization initiators function as a cationic photopolymerization initiator.

  Examples of the thermal polymerization initiator include substances that generate active species that cause polymerization of unsaturated bonds by heat. Examples of thermal polymerization initiators that generate active species by heat include peroxides and azo compounds.

Organic peroxides include benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, t-butyl peroxide, 2-ethylhexanoate methyl ethyl ketone peroxide, cyclohexanone peroxide, methylcyclohexanone peroxide, methyl Acetoacetate peroxide, acetylacetate peroxide, 1,1-bis (t-hexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-hexylperoxy) -cyclohexane, 1,1 -Bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) -2-methylcyclohexane, 1,1-bis (t-butylperoxy)- Cyclohexane, 1,1-bis (t-butyl Luperoxy) cyclododecane, 1,1-bis (t-butylperoxy) butane, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, p-menthane hydroperoxide, diisopropylbenzene hydro Peroxide, 1,1,3,3-tetramethylbutyl hydroperoxide, cumene hydroperoxide, t-hexyl hydroperoxide, t-butyl hydroperoxide, α, α'-bis (t-butylperoxy) Diisopropylbenzene, dicumyl peroxide, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2 , 5-bis (t-butylperoxy) hexyne-3, a Sobutyryl peroxide, 3,5,5-trimethylhexanoyl peroxide, octanoyl peroxide, lauroyl peroxide, stearoyl peroxide, succinic acid peroxide, m-toluoyl benzoyl peroxide, benzoyl peroxide, di-n -Propyl peroxydicarbonate, diisopropyl peroxydicarbonate, bis (4-t-butylcyclohexyl) peroxydicarbonate, di-2-ethoxyethyl peroxydicarbonate, di-2-ethoxyhexyl peroxydicarbonate, di -3-methoxybutyl peroxydicarbonate, di-s-butylperoxydicarbonate, di (3-methyl-3-methoxybutyl) peroxydicarbonate, α, α'-bis (neodecano) Luperoxy) diisopropylbenzene, cumylperoxyneodecanoate, 1,1,3,3-tetramethylbutylperoxyneodecanoate, 1-cyclohexyl-1-methylethylperoxyneodecanoate, t-hexylper Oxyneodecanoate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t
-Butyl peroxypivalate, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexanoate, 1-cyclohexyl-1-methylethylperoxy-2-ethylhexanoate, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-hexylperoxyisopropyl Monocarbonate, t-butylperoxyisobutyrate, t-butylperoxymalate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate, t-butylperoxy Isopropyl monocarbonate, t-butylperoxy-2-ethylhexyl monocarbo Tert-butyl peroxyacetate, t-butylperoxy-m-toluylbenzoate, t-butylperoxybenzoate, bis (t-butylperoxy) isophthalate, 2,5-dimethyl-2,5-bis (M-toluylperoxy) hexane, t-hexylperoxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, t-butylperoxyallyl monocarbonate, t-butyltrimethylsilyl peroxide, 3,3 ′, 4,4′-tetra (t-butylperoxycarbonyl) benzophenone, 2,3-dimethyl-2,3-diphenylbutane and the like can be mentioned.

  Examples of inorganic peroxides include ammonium persulfate, sodium persulfate, and potassium persulfate.

  Examples of the azo compound include 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 1-[(1-cyano-1-methylethyl) azo] formamide, 1,1′-azobis (cyclohexane-1-carbohydrate). Nitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobisisobutyronitrile, azobisisovaleronitrile, 2,2′-azobis (2,4-dimethylvaleronitrile) ), 2,2′-azobis (2,4-dimethyl-4-methoxyvaleronitrile), 2,2′-azobis (2-methylpropionamidine) dihydrochloride, 2,2′-azobis (2-methyl-N) -Phenylpropionamidine) dihydrochloride, 2,2'-azobis [N- (4-chlorophenyl) -2-methylpropionamidine]] Hydrochloride, 2,2′-azobis [N- (4-hydrophenyl) -2-methylpropionamidine]] dihydrochloride, 2,2′-azobis [2-methyl-N- (phenylmethyl) propionamidine] dihydro Chloride, 2,2′-azobis [2-methyl-N- (2-propenyl) propionamidine] dihydrochloride, 2,2′-azobis [N- (2-hydroxyethyl) -2-methylpropionamidine]] dihydro Chloride, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydro Chloride, 2,2′-azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl Propane] dihydrochloride, 2,2′-azobis [2- (3,4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (5-hydroxy-3) , 4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2′-azobis {2- [1- (2-hydroxyethyl) -2-imidazolin-2-yl] propane} dihydrochloride 2,2′-azobis [2- (2-imidazolin-2-yl) propane], 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxyethyl ] Propionamide}, 2,2′-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) ethyl] propionamide}, 2,2′-azobis [2- Methyl-N- (2-hydroxyethyl) propionamide], 2,2′-azobis (2-methylpropionamide), 2,2′-azobis (2,4,4-trimethylpentane), 2,2′- Azobis (2-methylpropane), dimethyl 2,2-azobis (2-methylpropionate), 4,4'-azobis (4-cyanopentanoic acid), 2,2'-azobis [2- (hydroxymethyl) Propionitrile] and the like.

  These thermal radical polymerization initiators can be used alone or in combination of two or more. Some of the exemplified thermal radical polymerization initiators function as thermal cationic polymerization initiators. Examples of the compound that can be a polymerization initiator for cationic polymerization and radical polymerization by such heat include 2,2'-azobisdimethylvaleronitrile and the like.

  The ink composition of the present embodiment is an azo compound (for example, 2,2′-azo) among the various polymerization initiators from the viewpoint of allowing the organic solvent to be polymerized (solidified) more easily. It is preferable to contain bisisobutyronitrile (Wako Pure Chemical Industries, Ltd .: V-60 etc.).

  The content of the polymerization initiator contained in the ink composition is preferably 1% by mass to 20% by mass and more preferably 3% by mass to 15% by mass with respect to the entire ink composition. preferable. By setting it as the said range, superposition | polymerization of the above-mentioned organic solvent can be started rapidly, and the flow of an ink composition can be suppressed.

1.3. Colorant The colorant contained in the ink composition of this embodiment may be either a pigment or a dye.

  Examples of the pigment include organic pigments such as azo, phthalocyanine, condensed polycyclic, nitro, nitroso, hollow resin particles, and polymer particles (brilliant carmine 6B, lake red C, watching red, disazo yellow, hansa). Yellow, phthalocyanine blue, phthalocyanine green, alkali blue, aniline black, etc.); metals such as cobalt, iron, chromium, copper, zinc, lead, titanium, vanadium, manganese, nickel, titanium oxide, zinc oxide, antimony oxide, Metal oxides and sulfides such as zinc sulfide and zirconium oxide, and carbon blacks (CI pigment black 7) such as furnace carbon black, lamp black, acetylene black, and channel black, as well as loess, ultramarine blue, And bitumen etc. It can be used as the inorganic pigment.

As carbon black, no. 2300, no. 900, MCF88, No. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, no. 2200B (Mitsubishi Chemical Co., Ltd.), Raven 5750, Raven 5250, Raven 5000, Raven 3500, Raven 1255, Raven 700, etc. (above, Columbia Carbon Co., Ltd.), Rega1 400R, Rega1 330R, Regal 1660R, Mul 6000L , Monarch 700, Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. (above, manufactured by Cabot Corporation), Color Black FW1, Color Black
FW2, Color Black FW2V, Color Black FW18, Color Black FW200, Color B1ack S150, Color Black S160, Color Black S170, Printex 35, Printex U, Printex V, Printex 140U, Special Black 6, Special Black 5, Special Black 4A, Special Black 4 (manufactured by Degussa) or the like.

Examples of white pigments include C.I. I. Pigment White 1 (basic lead carbonate), 4 (zinc oxide), 5 (mixture of zinc sulfide and barium sulfate), 6 (titanium oxide), 6: 1 (titanium oxide containing other metal oxides), 7 (Zinc sulfide), 18 (calcium carbonate), 19 (clay), 20 (titanium mica), 21 (barium sulfate), 22 (natural barium sulfate), 23 (
Gloss white), 24 (alumina white), 25 (gypsum), 26 (magnesium oxide / silicon oxide), 27 (silica), 28 (anhydrous calcium silicate) and the like.

  Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 4, 5, 6, 7, 10, 11, 12, 13, 14, 16, 17, 24, 34, 35, 37, 53, 55, 65, 73, 74, 75, 81, 83, 93, 94, 95, 97, 98, 99, 108, 109, 110, 113, 114, 117, 120, 124, 128, 129, 133, 138, 139, 147, 151, 153, 154, 167, 172, 180 and the like.

  Examples of magenta pigments include C.I. I. Pigment Red 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 30, 31, 32, 37, 38, 40, 41, 42, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 88, 112, 114, 122, 123, 144, 146, 149, 150, 166, 168 170, 171, 175, 176, 177, 178, 179, 184, 185, 187, 202, 209, 219, 224, 245, and C.I. I. Pigment violet 19, 23, 32, 33, 36, 38, 43, 50 and the like.

  Examples of cyan pigments include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 1, 15: 2, 15: 3, 15:34, 15: 4, 16, 18, 22, 25, 60, 65, 66, and C.I. I. Bat Blue 4, 60 and the like.

  Examples of pigments other than black, white, yellow, magenta and cyan include C.I. I. Pigment green 7, 10, and C.I. I. Pigment brown 3, 5, 25, 26, and C.I. I. Pigment orange 1, 2, 5, 7, 13, 14, 15, 16, 24, 34, 36, 38, 40, 43, 63 and the like.

  When preparing an ink composition using a pigment, a pigment dispersion in which a pigment is dispersed in advance may be prepared, and the pigment dispersion may be added to the ink composition and contained. As a method for obtaining such a pigment dispersion, a method of dispersing a self-dispersed pigment in a dispersion medium without using a dispersant, a method of dispersing a pigment in a dispersion medium using a polymer dispersant, and a surface treatment are performed. There is a method of dispersing a pigment in a dispersion medium. In addition, dyes may be used as coloring materials, and dyes that can be used in ink compositions include direct dyes, acid dyes, food dyes, basic dyes, reactive dyes, oil-soluble dyes, disperse dyes, building dyes. Various dyes that are usually used in ink jet recording, such as dyes, soluble vat dyes, and reactive disperse dyes, can be used.

  The content of the color material contained in the ink composition of the present embodiment is not particularly limited. The content of the color material is, for example, 0.01% by mass or more and 80% by mass or less, preferably 0.1% by mass or more and 50% by mass or less, more preferably 1% by mass or more and 30% by mass or less.

1.4. Other Components The ink composition of the present embodiment can contain other organic solvents, surfactants, sensitizers, resins and the like in addition to the organic solvent, the polymerization initiator, and the coloring material.

1.4.1. Other Organic Solvent The ink composition of the present embodiment may contain various organic solvents in addition to the organic solvent having a 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher. it can. As such an organic solvent, for example, as an organic solvent having a 50% distillation point of 280 ° C. or less, “AF-4, AF-7, Naphthezol M, Naphthezol L, Teclean N-16, Teclean N, manufactured by Nippon Petrochemical Co., Ltd. -20, Teclean N-22, 0 Solvent L, 0 Solvent M, 0 Solvent H, Isosol 300, Isosol 400, Clean Sol G ", Exxon" Exxol D80, Solvesso 200, Isopar M, Isopar L ", etc. Can be mentioned. In addition, an organic solvent having a 50% distillation point of 280 ° C. or lower may be contained. Examples of the organic solvent having a 50% distillation point of 280 ° C. or lower include diethylene glycol monobutyl ether, ethylene glycol monobutyl ether, propylene glycol monobutyl ether, A propylene glycol dibutyl ether or the like having a 50% distillation point of 280 ° C. or lower can be selected. In addition, an organic solvent having an iodine value of less than 100 may be included, and examples of such an organic solvent include coconut oil, olive oil, tonsil oil, peanut oil, and coconut oil.

  In addition, the ink composition of the present embodiment may contain an alcohol solvent or an ester solvent. For example, isomyristyl alcohol, isopalmityl alcohol, isostearyl alcohol, isoicosyl alcohol, isohexacosanol, You may contain castor oil etc. Furthermore, the ink composition of the present embodiment may contain an aliphatic hydrocarbon solvent, an aromatic hydrocarbon solvent, and the like. Specific examples of the aliphatic hydrocarbon solvent include commercially available teclean N-16, teclean N-20, teclean N-22, Nisseki Naphthezol L, Nisseki Naphthezol M, Nisseki Naphthezol H, No. 0 Solvent L, 0 No. Solvent M, No. 0 Solvent H, Nisseki Isosol 300, Nisseki Isosol 400, AF-4, AF-5, AF-6, AF-7 (all are trade names, manufactured by Nippon Oil Corporation); IsoparG, IsoparH , IsoparL, IsoparM, ExxolD40, ExxolD80, Exxol100, ExxolD130, ExxolD140 (all trade names, manufactured by Exxon) and the like. Specific examples of the aromatic hydrocarbon solvent include Nisseki Cleansol G (alkylbenzene) (trade name, manufactured by Nippon Oil Corporation).

  Even when the ink composition of the present embodiment contains such an organic solvent having a low iodine value, the organic solvent having the above 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher is polymerized. By doing so, since it is taken in into the network (network structure) of a molecule | numerator, the fluidity | liquidity of an ink composition can be suppressed.

1.4.2. Surfactant The ink composition of the present embodiment may contain a surfactant. In particular, when a pigment is contained as a coloring material, the surfactant can function as a pigment dispersant.

  Examples of the pigment dispersant (surfactant) include a hydroxyl group-containing carboxylic acid ester, a salt of a long-chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a salt of a long chain polyaminoamide and a polar acid ester, and a high molecular weight Unsaturated acid ester, polymer copolymer, modified polyurethane, modified polyacrylate, polyether ester type anionic activator, naphthalene sulfonic acid formalin condensate salt, aromatic sulfonic acid formalin condensate salt, polyoxyethylene alkyl phosphoric acid Esters, polyoxyethylene nonylphenyl ether, polyester polyamines, stearylamine acetate, and the like can be used.

  Specific examples of the pigment dispersant (surfactant) include Solsperse 17000, Solsperse 18000, Solsperse 13940, Solsperse 28000 (all trade names, manufactured by Lubrizol); Florene DOPA-15B (trade name, manufactured by Kyoeisha Chemical Co., Ltd.) DA-703-50, DA-7300, DA234 (all trade names, manufactured by Enomoto Kasei Co., Ltd.); Disperbyk-101 (trade names, manufactured by Byk Chemie), Hinoact (trade names, manufactured by Kawaken Fine Chemical Co., Ltd.), etc. It is done. Among these, a pigment dispersant having a polyesteramine structure can be particularly preferably used, and specific examples include Solsperse 18000, Solsperse 13940, Solsperse 28000 (all trade names, manufactured by Lubrizol Corporation) and the like.

1.4.3. Sensitizer The ink composition of the present embodiment may contain a sensitizer. Examples of the sensitizer include quinone compounds, anthracene compounds, 4-methoxy-1-naphthol, fluorene, pyrene, and stilbene.

  As an anthracene compound, for example, anthracene, 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, 2-ethyl-9,10-dimethoxyanthracene, 2-ethyl-9,10- Diethoxyanthracene, 2-ethyl-9,10-dipropoxyanthracene, 4′-nitrobenzyl-9,10-dimethoxyanthracene-2-sulfonate, 4′-nitrobenzyl-9,10-diethoxyanthracene-2-sulfonate And 4'-nitrobenzyl-9,10-dipropoxyanthracene-2-sulfonate.

  Among these, 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, and 9,10-dipropoxyanthracene are preferable from the viewpoints of excellent solubility in the ink composition and high sensitizing action. Commercially available products of these sensitizers include anthracure UVS-1331, 1221, 1101, and ET-2111 (manufactured by Kawasaki Kasei Kogyo Co., Ltd.).

  When a sensitizer is used, the total amount of the polymerization initiator and the sensitizer is 3% by mass or more, preferably 6% by mass or more, more preferably 10% by mass or more based on the total amount of the ink composition. It is preferable to do.

1.4.4. Resin The ink composition of the present embodiment may contain a resin. Examples of the resin include urethane resin, styrene acrylic resin, acrylic resin and the like.

  The urethane resin is not particularly limited as long as it has a urethane bond in the molecule, but in addition to the urethane bond, a polyether type urethane resin having an ether bond in the main chain, and a polyester type urethane having an ester bond in the main chain. Resin, polycarbonate-type urethane resin containing a carbonate bond in the main chain, and the like can also be used.

  Examples of commercially available urethane resins include Sancure 2710 (manufactured by Nihon Lubrizol), Permarin UA-150 (manufactured by Sanyo Chemical Industries), Superflex 150, 420, 460, 470, 610, 700 (and above, Ichi Kogyo Seiyaku Co., Ltd.), NeoRez R-9660, R-9637, R-940 (above, manufactured by Enomoto Kasei Co., Ltd.), Adekabon titer HUX-380, 290K (above, made by ADEKA Corporation), Takerak (R) ) W-605, W-635, WS-6021 (above, manufactured by Mitsui Chemicals, Inc.) and the like.

Examples of commercially available styrene acrylic resins and acrylic resins include Mobile Vinyl 966A, Mobile Vinyl 7320 (manufactured by Nippon Synthetic Chemical Co., Ltd.), Microgel E-1002, Microgel E-5002 (manufactured by Nippon Paint Co., Ltd.), Bon Coat 4001 Boncoat 5454 (above, manufactured by DIC Corporation), SAE1014 (manufactured by Zeon Corporation), Cybinol SK-200 (manufactured by Seiden Chemical Co., Ltd.), Jonkrill 7100, Jonkrill 390, Jonkrill 711, Jonkrill 511, John Krill 7001, John Krill 632, John Krill 741, John Krill 450, John Krill 840, John Krill 74J, John Krill HRC-1645J, John Krill 734, John Krill 852, John Krill 7600 John Crill 775, John Crill 537J, John Crill 1535, John Crill PDX-7630A, John Crill 352J, John Crill 352D, John Crill PDX-7145, John Crill 538J, John Crill 7640, John Crill 7641, John Crill 631, John Crill 790, Jonkrill 780, Jonkrill 7610 (above, manufactured by BASF), NK binder R-5HN (made by Shin-Nakamura Chemical Co., Ltd.), and the like.

1.4.5. Others The ink composition of the present embodiment may contain a thermal polymerization inhibitor. The thermal polymerization inhibitor can be used to suppress thermal polymerization or temporal polymerization of the organic solvent described above.

  Specific examples of the thermal polymerization inhibitor include 4-methoxyphenol, hydroquinone, alkyl or aryl-substituted hydroquinone, t-butylcatechol, pyrogallol, 2-hydroxybenzophenone, 4-methoxy-2-hydroxybenzophenone, and first chloride. Copper, phenothiazine, chloranil, naphthylamine, β-naphthol, 2,6-di-t-butyl-4-cresol, 2,2, -methylenebis (4-methyl-6-t-butylphenol), pyridine, nitrobenzene, dinitrobenzene , Picric acid, 4-toluidine, methylene blue, copper and organic chelating agent reactant, methyl salicylate, and phenothiazine, nitroso compound, chelate of nitroso compound and Al, and the like. Examples of the thermal radical polymerization inhibitor include Irgastab UV-10 and UV-22 (manufactured by Ciba Specialty Chemicals).

  The ink composition of the present embodiment may contain a chain transfer agent. As the chain transfer agent, known N-phenylglycines, phenoxyacetic acids, thiophenoxyacetic acids, mercaptothiazole, and the like can be used. Specifically, chain transfer agents having a carboxyl group such as mercaptosuccinic acid, mercaptoacetic acid, mercaptopropionic acid, methionine, cysteine, thiosalicylic acid and derivatives thereof; mercaptoethanol, mercaptopropanol, mercaptobutanol, mercaptopropanediol, mercapto Chain transfer agents having a hydroxyl group such as butanediol, hydroxybenzenethiol and derivatives thereof; 1-butanethiol, butyl-3-mercaptopropionate, methyl-3-mercaptopropionate, 2,2- (ethylenedioxy) Diethanethiol, ethanethiol, 4-methylbenzenethiol, dodecyl mercaptan, propanethiol, butanethiol, pentanethiol, 1-octanethiol, cyclopentanethiol Cyclohexane thiol, thioglycerol, 4,4-like thiobisbenzenethiol the like.

  The ink composition of this embodiment may contain a polymerization accelerator. Although it does not specifically limit as a polymerization accelerator, Darocur EHA, EDB (made by Ciba Specialty Chemicals) etc. are mentioned.

  Furthermore, the ink composition of the present embodiment can contain known and publicly used components that can be used in general oil-based inks. Examples of such components include wetting agents, penetrating solvents, pH adjusting agents, preservatives, fungicides, and the like. Furthermore, the ink composition of the present embodiment includes a leveling additive, a matting agent, a polyester resin, a polyurethane resin, a vinyl resin, an acrylic resin, and a rubber resin for adjusting film properties as necessary. , Waxes can be contained.

1.5. Physical properties of ink composition The ink composition of the present embodiment is used in an ink jet recording method. Therefore, the viscosity is 30 mPa · s or less at 25 ° C., more preferably 1 mPa · s or more and 20 mPa · s or less, and further preferably 2 mPa · s or more and 10 mPa · s or less. Within this range, it is possible to ensure the ejection stability of the ink composition in the step of ejecting the ink composition and depositing the ink composition on the recording medium by the ink jet recording apparatus. The viscosity of the ink composition of the present embodiment can be adjusted by the blending amount of each component.

1.6. Action Effect, etc. The ink composition of this embodiment can polymerize (solidify) an organic solvent having a large iodine value (so-called semi-drying oil and / or drying oil) with a polymerization initiator. Thereby, it is possible to suppress the movement of the color material in the recording medium, and it is possible to perform recording with good color development and reduced offset.

  Moreover, since the 50% distillation point contains an organic solvent having a temperature of 300 ° C. or higher, volatilization of the entire organic solvent is easily suppressed, and odors and the like are less likely to be generated. Further, volatilization of the entire organic solvent is easily suppressed, and clogging of the nozzles of the ink jet recording apparatus can be suppressed.

2. Ink Set The ink set according to the present embodiment includes a first liquid containing an organic solvent having a 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher, and a coloring material, an organic solvent, and polymerization. And a second liquid containing an initiator.

  The first liquid of the ink set of the present embodiment is a composition obtained by removing the polymerization initiator from the above ink composition. Therefore, detailed description is omitted. In addition, the polymerization initiator contained in the second liquid of the ink set of the present embodiment is the same as the polymerization initiator contained in the ink composition described above, and thus the description thereof is omitted.

  The organic solvent contained in the second liquid of the ink set of the present embodiment is not particularly limited, and the above-described organic solvent having a 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher, “1 Organic solvents exemplified in the section “4.1. Other organic solvents” can be used. Further, the 50% distillation point and iodine value of the organic solvent contained in the second liquid of the ink set of the present embodiment are not limited, but the 50% distillation point is 300 ° C. or higher and the iodine value is 100. Employing the above organic solvent is preferable because the fluidity of the mixed liquid can be more efficiently lowered when the first liquid and the second liquid are attached to the recording medium. Furthermore, it is more preferable to use an organic solvent having a low iodine value (for example, 80 or less) as the organic solvent contained in the second liquid of the ink set of the present embodiment, since it is difficult to solidify before the second liquid is used.

  According to such an ink set, the organic solvent having a large iodine value (so-called semi-drying oil and / or drying oil) contained in the first liquid is polymerized (solidified) by the polymerization initiator contained in the second liquid. Can do. Thereby, it is possible to suppress the movement of the color material in the recording medium, and it is possible to perform recording with good color development and reduced offset.

  The surfactant, sensitizer, resin, polymerization inhibitor, etc. described in the section “1.4. Other components” may be blended in one or both of the first liquid and the second liquid. And can be appropriately blended according to the purpose. In addition, the ink set of the present embodiment can appropriately include other colors of ink.

3. Image Forming Method The image forming method according to this embodiment is performed using the above-described ink composition or using the above-described ink set. In addition to the steps described below, the image forming method according to the present embodiment may include a step of attaching another liquid, a drying step, and the like as necessary.

3.1. Image Forming Method Using Ink Composition The above-described image forming method using an ink composition includes a step of attaching an ink composition to a recording medium by an ink jet recording apparatus, and heating the ink composition attached to the recording medium. Or irradiating the ink composition attached to the recording medium with light. The image forming method of the present embodiment may include both a step of heating the ink composition and a step of irradiating the ink composition with light, and the number and order thereof are also arbitrary.

3.1.1. The step of attaching the ink composition The step of attaching the ink composition is performed using an ink jet recording apparatus. The ink jet recording apparatus is not particularly limited, and a known apparatus can be appropriately used. This step is performed so that the ink composition can be discharged from at least one nozzle of the ink jet recording apparatus. Further, the recording medium to which the ink jet recording method of the present embodiment is applied is not particularly limited, and can be applied to various fabrics, various papers, and the like.

3.1.2. Step of Heating Ink Composition The step of heating the ink composition is not particularly limited as long as it is a method capable of generating active species from a thermal polymerization initiator present in the ink composition. In this step, for example, a heat roller or the like is provided in the ink jet recording apparatus, and after the ink composition adheres to the recording medium, a method of heating with a heroler, after the ink composition adheres to the recording medium, warm air is applied to the recording medium. Can be performed by a method of spraying, a method of combining them, or the like. Furthermore, forced air heating, radiation heating, conductive heating, high frequency heating, microwave heating, or the like may be used. The heating may be performed in the ink jet recording apparatus, or may be performed in an apparatus other than the ink jet recording apparatus.

  Although the temperature range at the time of applying heat in this step depends on the type of polymerization initiator and the type of media, for example, it is 60 ° C or higher, preferably 60 ° C to 150 ° C, more preferably 80 ° C to It is in the range of 120 ° C.

3.1.3. The step of irradiating the ink composition with light The step of irradiating the ink composition with light is not particularly limited as long as it is a method capable of generating active species from the photopolymerization initiator present in the ink composition. This step can be performed by, for example, an ink jet recording apparatus provided with an ultraviolet irradiation device capable of performing irradiation with ultraviolet rays as light (radiation). The position where the ultraviolet irradiation device of the ink jet recording apparatus is provided is not limited. For example, in the case of the serial type, the side of the carriage, on the downstream side in the recording medium conveyance direction as viewed from the head, and in the case of the line type, the head When viewed from the side or the head, it can be the downstream side in the recording medium conveyance direction. The light irradiation may be performed in an inkjet recording apparatus, or may be performed in an apparatus other than the inkjet recording apparatus.

  Examples of the light used in this step include ultraviolet light, visible light, far ultraviolet light, g-line, h-line, i-line, KrF excimer laser light, ArF excimer laser light, and the like. Although it does not restrict | limit especially as an irradiation light source of light, The light source from which the light of a wavelength of 385-420 nm is obtained is more preferable from viewpoints, such as a maintenance.

When visible light is used as the light, the amount of light applied to the ink composition is 10 mJ / cm ² or more and 20,000 mJ / cm ² or less, and preferably 50 mJ / cm ² or more and 15,000 mJ / cm. It can be performed within a range of ² or less.

  When visible light having a wavelength of 385 to 420 nm is used as the light, for example, the form Firefly (wavelength 400 nm) manufactured by Phoseon can be used as the visible light source. Light irradiation can also be performed by a visible light semiconductor element such as a light emitting diode (LED) or a semiconductor laser.

  When ultraviolet rays are used as light, examples of irradiation with ultraviolet rays include lamps such as metal halide lamps, xenon lamps, carbon arc lamps, chemical lamps, low-pressure mercury lamps, and high-pressure mercury lamps. For example, a commercially available product such as H lamp, D lamp, V lamp manufactured by Fusion System, SubZero 055 manufactured by Integration, or the like can be used. Also, ultraviolet irradiation can be performed by an ultraviolet light emitting semiconductor element such as an ultraviolet light emitting diode (ultraviolet LED) or an ultraviolet light emitting semiconductor laser.

3.2. Image Forming Method Using Ink Set The above-described image forming method using an ink set includes a step of attaching a first liquid to a recording medium by an ink jet recording apparatus and a step of attaching a second liquid to the recording medium by an ink jet recording apparatus. And including.

  Both the step of attaching the first liquid and the step of attaching the second liquid are performed using an ink jet recording apparatus. The ink jet recording apparatus is not particularly limited, and a known apparatus can be appropriately used. This step is performed so that the first liquid and the second liquid can be discharged from at least one nozzle of the ink jet recording apparatus, respectively.

  The step of attaching the first liquid and the step of attaching the second liquid may be performed in any order, or may be performed simultaneously. However, the first liquid and the second liquid attached to the recording medium in the step of attaching the first liquid and the step of attaching the second liquid are attached so that at least a part of the first liquid and the second liquid are mixed on the recording medium. Further, the number of times of the step of attaching the first liquid and the step of attaching the second liquid is not limited, and the time interval at which the step is performed is not particularly limited.

The amount of the first liquid and the second liquid attached to the recording medium can be appropriately set depending on the amount of the organic solvent having a high iodine value contained in both and the amount of the polymerization initiator contained in the second liquid. For example, the amount of the first liquid attached to the recording medium in the step of attaching the first liquid is 1 mg / inch ^{2 to} 30 mg / inch ² , preferably 4 mg / inch ^{2 to} 20 mg / inch ² and more preferably. Is 7 mg / inch ² or more and 15 mg / inch ² or less. The amount of the second liquid attached to the recording medium in the step of attaching the second liquid is 1 mg / inch ^{2 to} 30 mg / inch ² , preferably 4 mg / inch ^{2 to} 20 mg / inch ² and more preferably. Is 7 mg / inch ² or more and 15 mg / inch ² or less. If the amount of the first liquid and the second liquid attached to the recording medium is within this range, it is easy to reduce the fluidity of the organic solvent, and the effect of retaining the coloring material on the surface side of the recording medium is obtained. Can do.

3.2.2. The process of heating the 1st liquid and the 2nd liquid, The process of irradiating light to the 1st liquid and the 2nd liquid The process of heating the 1st liquid and the 2nd liquid, The process of irradiating light to the 1st liquid and the 2nd liquid Are respectively the same as “3.1.2. Step of heating ink composition” and “3.1.3. Step of irradiating light to ink composition”. This step is a step of heating the area where the first liquid and the second liquid are adhered on the recording medium or a step of irradiating the area with light, and “3.1.2. Step of Heating Ink Composition” In the description of “3.1.3. Step of irradiating light to ink composition”, detailed description is omitted by replacing the ink composition with the first liquid and the second liquid.

3.3. Effects and the like According to such an image forming method, an organic solvent having a high iodine value (so-called semi-drying oil and / or drying oil) can be polymerized (solidified) with a polymerization initiator. Thereby, it is possible to suppress the movement of the color material in the recording medium, and it is possible to perform recording with good color development and reduced offset.

4). EXAMPLES Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

4.1. Preparation of Ink Composition The ink compositions of Examples 1 to 14 and Comparative Examples 1 to 4 were mixed with the organic solvent described in Table 1 in a container in the amount shown in the table, and Solsperse 13940 (dispersant: Avicia) and carbon black (MA100: manufactured by Mitsubishi Chemical Corporation), polymerization initiator (IRGACURE819 (photopolymerization initiator: manufactured by Ciba Japan)) or V-60 (thermal polymerization initiator: manufactured by Wako Pure Chemical Industries, Ltd.) )), A sensitizer (Anthracure UVS-121: Kawasaki Kasei Kogyo Co., Ltd.) is added so as to have the composition shown in the table, mixed and stirred with a magnetic stirrer for 2 hours, and then filtered through a membrane filter having a pore size of 5 μm. It was prepared by.

4.2. Preparation of 1st liquid The 1st liquid of Examples 15-19 and the comparative example 5 puts the organic solvent of Table 2 into the container with the compounding quantity of a table | surface, and mixes it, Solsperse 13940 (dispersing agent: Avicia company) And carbon black (MA100: manufactured by Mitsubishi Chemical Corporation) so as to have the composition shown in the table, and mixed and stirred for 2 hours with a magnetic stirrer, and then filtered through a membrane filter having a pore size of 5 μm.

4.3. Preparation of Second Liquid In the second liquids of Examples 15 to 19 and Comparative Example 5, the organic solvents described in Table 2 were mixed in a container in the amount shown in the table, and this was mixed with a polymerization initiator (IRGACURE 819 (photopolymerization). Initiator: manufactured by Ciba Japan) or V-60 (thermal polymerization initiator: manufactured by Wako Pure Chemical Industries, Ltd.)) is added so as to have the composition shown in the table, and after mixing and stirring with a magnetic stirrer for 2 hours, pore size It was prepared by filtering through a 5 μm membrane filter.

4.4. Evaluation method ≪OD value≫
About the ink composition of Examples 1-14 and Comparative Examples 1-4, the prepared ink composition is introduce | transduced into the cartridge of an inkjet printer (The Seiko Epson Corporation make, type PX-B700), and is connected to the said cartridge. After confirming ejection from a plurality of nozzles, a solid pattern was printed on one sheet of A4 paper (plain paper: Xerox P paper manufactured by Fuji Xerox Co., Ltd.). The coating amount (adhesion amount) of the ink composition at that time is shown in Table 1.

  In Examples (Examples 1 to 6 and 13) in which IRGACURE 819 (photopolymerization initiator) was used as the polymerization initiator, the surface of the printer exit was adjusted so that the entire recording surface of the recording medium could be irradiated with light having a wavelength of 450 nm. A light source was attached, and the recording medium was conveyed so that the light was irradiated after the ink composition was attached.

  In addition, in the examples (Examples 7 to 12 and 14) using V-60 (thermal polymerization initiator) as a polymerization initiator, a heater fan is installed at the printer outlet so that hot air of about 100 ° C. is blown onto the recording medium. The recording medium was transported so that the ink composition was heated after the ink composition was attached.

Furthermore, in the examples where no polymerization initiator is used (Comparative Examples 1 to 4), the entire recording surface of the recording medium is
The recording medium was conveyed by irradiating light with a wavelength of 0 nm and blowing hot air of about 100 ° C. on the recording medium.

  Then, the OD value of the pattern was measured with a Gretag densitometer (manufactured by Gretag Macbeth).

  For Examples 15 to 19 and Comparative Example 5, the prepared first liquid and second liquid were respectively introduced into a cartridge of an inkjet printer (manufactured by Seiko Epson Corporation, type PX-B700), and communicated with the cartridge. After confirming that the second liquid adheres to the area after the first liquid adheres sequentially from the nozzle, the A4 paper (plain paper: Xerox P paper manufactured by Fuji Xerox Co., Ltd.) A solid pattern was printed. The application amounts (adhesion amounts) of the first liquid and the second liquid at that time are shown in Table 2.

  In the example using IRGACURE 819 (photopolymerization initiator) as the polymerization initiator (Example 17), a surface light source was mounted at the printer outlet so that the entire recording surface of the recording medium could be irradiated with light having a wavelength of 450 nm. The recording medium was conveyed so that the light was irradiated after the first liquid and the second liquid were attached.

  In the examples (Examples 15, 16, 18, and 19) using V-60 (thermal polymerization initiator) as the polymerization initiator, a heater fan is provided at the printer outlet so that hot air of about 100 ° C. is blown onto the recording medium. And the recording medium was conveyed so that the first liquid and the second liquid were heated after the first liquid and the second liquid were attached.

  Further, in an example in which no polymerization initiator is used (Comparative Example 5), the recording surface of the recording medium is irradiated with light having a wavelength of 450 nm, and hot air of about 100 ° C. is blown onto the recording medium to convey the recording medium. I went.

  Then, the OD value of the pattern was measured with a Gretag densitometer (manufactured by Gretag Macbeth).

In all cases, the evaluation criteria are as follows, and the results are shown in Tables 1 and 2.
○ ・ ・ ・ OD value 1.2 or more △ ・ ・ ・ OD value 1.0 or more and less than 1.2 × ・ ・ ・ OD value 1.0 or less

≪Inside-off≫
The OD value of the back surface of the A4 paper from which the OD value was measured was measured in the same manner. The evaluation criteria are as follows, and the results are shown in Tables 1 and 2.
○ ・ ・ ・ OD value less than 0.2 △ ・ ・ ・ OD value 0.2 or more and less than 0.3 × ・ ・ ・ OD value 0.3 or more

≪Storage stability≫
The ink composition of each example, the first liquid and the second liquid were put in a container and left at 40 ° C. for 1 week. Then, 10 g of each ink composition, the first liquid, and the second liquid were dropped on a mesh filter having a pore diameter of 10 μm, and the presence or absence of solid matter (foreign matter) precipitation was visually observed. .

The ink compositions of Examples 1 to 14 and Comparative Examples 1 to 4 were evaluated according to the following criteria, and the results are shown in Table 1.
○ ・ ・ ・ No solid matter △ ・ ・ ・ The number of solids is less than 5 × ・ ・ ・ The number of solids is 5 or more

The first liquid and the second liquid of Examples 15 to 19 and Comparative Example 5 were evaluated according to the following criteria, and the results are shown in Table 1.
○: No solids are observed in both the first and second liquids. Δ ... The total number of solids in the first and second liquids is less than 5. × ... The first and second liquids. The total number of liquid solids is 5 or more

≪Discharge stability≫
In each example and each comparative example, in the same manner as in the evaluation of the OD value, a test pattern was continuously printed on 30 sheets of A4 paper, and after the 30 sheets were printed, the nozzle check of the printer was performed, and the discharge stability was reduced as follows. Evaluation based on the criteria. The evaluation results are shown in Tables 1 and 2.
○ ・ ・ ・ No nozzle missing △ ・ ・ ・ No more than 5 nozzles missing, recovery after 1 cleaning × ・ ・ ・ No more than 10 nozzles missing, recovery after 2 or more cleanings

4.5. Evaluation result When Table 1 and Table 2 were seen, each Example was favorable in both color developability (OD value) and back-off. On the other hand, in each comparative example using no polymerization initiator, both the color developability (OD value) and the back-off were poor. In addition, it was found from the examples that the higher the ratio of the organic solvent having a higher iodine value, the better the color developability (OD value) and the back-off. Furthermore, when each Example was seen, even if it was a photoinitiator or a thermal-polymerization initiator, it turned out that a favorable result is obtained irrespective of the presence or absence of a sensitizer.

  These results are thought to be due to the fact that after the liquid adheres to the recording medium, the movement of the pigment accompanying the penetration of the organic solvent is suppressed. That is, it is considered that the pigment is kept in the vicinity of the surface of the recording medium due to the solidification of the organic solvent, and is less likely to be caused to flow due to permeation when the organic solvent adheres to the paper. In addition, this result may be partly due to the early binding of the recording medium and the pigment due to the solidification of the organic solvent.

  The present invention is not limited to the embodiments described above, and various modifications are possible. For example, the present invention includes substantially the same configuration (for example, a configuration having the same function, method and result, or a configuration having the same purpose and effect) as the configuration described in the embodiment. In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. In addition, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

Claims (11)

  An ink composition for inkjet recording, comprising an organic solvent having a 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher, a polymerization initiator, and a coloring material. In claim 1,
An ink composition comprising 20% by mass or more of the organic solvent. In claim 1 or claim 2,
An ink composition, wherein the organic solvent has an iodine value of 130 or more. In any one of Claims 1 to 3,
An ink composition comprising 60% by mass or more of the organic solvent. In any one of Claims 1 thru | or 4,
The ink composition, wherein the polymerization initiator is an azo compound. An image forming method using the ink composition according to any one of claims 1 to 5,
Attaching the ink composition to a recording medium with an inkjet recording apparatus;
Heating the ink composition attached to the recording medium, or irradiating the ink composition attached to the recording medium with light;
An image forming method. A first liquid containing an organic solvent having a 50% distillation point of 300 ° C. or higher and an iodine value of 100 or higher, and a coloring material;
A second liquid containing the organic solvent and a polymerization initiator;
An ink set for ink jet recording. An image forming method using the ink set according to claim 7,
Attaching the first liquid to a recording medium by an inkjet recording apparatus;
Attaching the second liquid to a recording medium with an inkjet recording apparatus;
An image forming method. In claim 8,
The image forming method, wherein the step of attaching the first liquid and the step of attaching the second liquid are performed in this order, in the reverse order, or simultaneously. In claim 8 or claim 9,
After the first liquid and the second liquid adhere to the recording medium, or at the same time as the first liquid and the second liquid adhere to the recording medium,
An image forming method, comprising: heating the first liquid and the second liquid attached to the recording medium, or irradiating the first liquid and the second liquid attached to the recording medium with light. . In any one of Claims 8 to 10,
On the recording medium, wherein the first liquid is deposited amount of 7 mg / inch ² or more 15 mg / inch ² or less, the second liquid is deposited in an amount of 7 mg / inch ² or more 15 mg / inch ² or less, the image forming method .