JP2011202143A - Ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition excellent in the aggregation control, film fixability, and/or clogging resilience of ink.SOLUTION: The ink composition is used which contains a hardly water-soluble alkanediol of a carbon number 7-10, and an alkylene glycol monoalkyl ether.

Description

Background of the Invention

TECHNICAL FIELD The present invention relates to an ink composition, and more particularly to an ink composition comprising a slightly water-soluble alkanediol and an alkylene glycol monoalkyl ether.

Background Art As an ink jet recording method, a method of discharging ink using electrostatic attraction (electric field control method), a method of discharging ink using driving pressure of a piezo element (drop on demand method or pressure) Various ink jet recording methods such as a pulse method) and a method of ejecting ink using a pressure generated by forming and growing bubbles by high heat (bubble or thermal jet method) are known. As a result, an extremely accurate image can be obtained. In addition, a pigment (hereinafter referred to as a metallic pigment) comprising a metallic powder having a metallic luster, such as aluminum (hereinafter also simply referred to as a metallic powder), and a coloring material for imparting any other color tone in an inkjet recording ink. May also be used).

  In order to impart a metallic luster glitter decoration or the like to an image obtained by an ink jet ink, an ink jet ink containing a fragment of a laminate having a metal vapor-deposited layer and a resin layer is disclosed (for example, JP-A-11-343436). Publication (refer patent document 1). In addition, for the purpose of improving the permeability to media, there has been reported a technique in which an acetylene glycol surfactant or a polyether-modified organosiloxane surfactant is added to a metallic pigment ink (for example, JP 2005-68252 (patent document 2)). Furthermore, a method for producing scaly metal flakes that does not curl and has a high aspect ratio and a technique for providing scaly metal flakes have been reported (for example, JP-A-2005-298906 (Patent Documents). 3)).

  Various ink-jet inks have been developed and used. For example, an inkjet ink using γ-butyrolactone (for example, JP 2009-227813 A (Patent Document 4)) has been known so far. The lactone solvent or lactam solvent may dissolve or swell the plastic member of the head, which may cause problems such as a decrease in head life and a decrease in print quality.

Japanese Patent Laid-Open No. 11-343436 JP 2005-68252 A JP 2005-298906 A JP 2009-227813 A

  The inventors of the present invention have recently made an ink composition containing a slightly water-soluble alkanediol having 7 to 10 carbon atoms and an alkylene glycol monoalkyl ether, thereby preventing ink aggregation, film fixability, and / or The knowledge that clogging recovery is excellent was obtained. The present invention is based on these findings.

  Accordingly, an object of the present invention is to provide an ink composition that is excellent in suppressing ink aggregation, film fixability, and / or clogging recovery.

  The ink composition according to the present invention is an ink composition comprising a slightly water-soluble alkanediol having 7 to 10 carbon atoms and an alkylene glycol monoalkyl ether.

  ADVANTAGE OF THE INVENTION According to this invention, the ink composition excellent in the aggregation suppression of an ink, film fixing property, and / or clogging recovery property can be provided.

Detailed description of the invention

Ink Composition The ink composition according to the present invention is an ink composition containing a slightly water-soluble alkanediol having 7 to 10 carbon atoms and an alkylene glycol monoalkyl ether. Ink composition suppression, film fixability, and / or clogging recovery can be achieved by including, as essential components, a water-soluble alkanediol having 7 to 10 carbon atoms and an alkylene glycol monoalkyl ether in the ink composition. Excellent. Hereinafter, each component contained in the ink composition of the present invention will be described.

<Slightly water-soluble alkanediol>
The ink composition according to the present invention comprises a slightly water-soluble alkanediol having 7 to 10 carbon atoms. Examples of the slightly water-soluble alkanediol include 1,2-heptanediol, 1,2-octanediol, 1,8-octanediol, 5-methyl-1,2-hexanediol, 4-methyl-1, Examples include 2-hexanediol and 4,4-dimethyl-1,2-pentanediol. Among these, from the viewpoint of gloss, a water-insoluble 1,2-alkanediol having 7 to 10 carbon atoms is more preferable, and 1,2-octanediol is more preferable.

  The slightly water-soluble alkanediol is preferably contained in an amount of 0.1 to 10.0% by weight, more preferably 1.0 to 6.0% by weight, based on the entire ink composition. By containing the poorly water-soluble alkanediol in an amount of 2.0 to 4.0% by weight based on the entire ink composition, the ink aggregation is further suppressed, film fixing property, and / or clogging recovery property is further improved.

<Alkylene glycol monoalkyl ether>
The ink composition according to the present invention comprises an alkylene glycol monoalkyl ether. The alkylene glycol monoalkyl ether is not particularly limited, and examples thereof include triethylene glycol monomethyl ether, diethylene glycol monobutyl ether, and diethylene glycol monoisobutyl ether. From the viewpoint of cohesiveness, monomethyl ether of alkylene glycol is more preferable, and from the viewpoint of environmental toxicity and ecotoxicity, triethylene glycol monomethyl ether is preferable. According to a preferred embodiment of the present invention, the alkylene glycol monoalkyl ether has a latent heat of vaporization of 80 cal / g or less and a molecular weight of 170 or less. By using an alkylene glycol monoalkyl ether whose latent heat of vaporization and molecular weight are within the above ranges, the ink composition of the present invention is excellent in the efficiency of heat evaporation vaporization drying and blast diffusion vaporization drying immediately after printing, environmental toxicity and ecotoxicity. Becomes lower.

  The alkylene glycol monoalkyl ether is preferably contained in an amount of 30% by weight or more, more preferably 50% by weight or more, and still more preferably 80% by weight or more based on the entire ink composition. Further, the alkylene glycol monoalkyl ether having a latent heat of vaporization of 80 cal / g or less and a molecular weight of 170 or less, which is a preferred embodiment of the present invention, is preferably contained in an amount of 30% by weight or more based on the total ink composition. More preferably, it is contained in an amount of at least 80% by weight, more preferably at least 80% by weight. This is because the main solvent is preferably contained in a larger amount than the other solvents contained in the ink.

<Metal foil piece>
According to a preferred aspect of the present invention, the ink composition of the present invention preferably includes a metal foil piece. When a metal foil piece is included in the ink composition of the present invention, it is more preferable that the following color pigment is not included in the ink composition of the present invention. The metal foil piece is not particularly limited as long as the effect of the present invention is exhibited, but the composite pigment base material having a structure in which a release resin layer and a metal or metal compound layer are sequentially laminated on a sheet-like base material surface. What peeled and crushed from the sheet-like base material at the interface between the sheet-like base material and the peeling resin layer is preferable.

  The metal foil pieces contained in the ink composition of the present invention are not particularly limited as long as the effects of the present invention are exhibited, but the average thickness is 30 to 100 nm, and the 50% volume average particle diameter is 1.0 to 4.0 μm. And the maximum particle size in the particle size distribution is preferably 12 μm or less, and from the viewpoint of improving the recording stability, the average thickness is 30 to 100 nm, and the 50% volume average particle size is 1.0 to 2.0 μm. More preferably, the maximum particle size in the particle size distribution is 10 μm or less. Here, the particle diameter can be measured by a light scattering method, for example, using Microtrac UPA (Microtrac Inc.). The content of the metal foil pieces contained in the ink composition of the present invention is not particularly limited as long as the effect of the present invention is exhibited, but is preferably 1.0 to 10.0% by weight with respect to the ink composition. It is more preferably 0 to 8.0% by weight.

  As long as the metal or metal compound used for the metal or metal compound layer of the composite pigment base material for producing the metal foil piece contained in the ink composition of the present invention has a function such as having a metallic luster, etc. Although not particularly limited, aluminum, silica, titanium, zinc, copper, nickel, silver, gold, platinum, chromium, tin, indium, etc. are used, and these simple metals, metal compounds, or alloys thereof and As an example, at least one of these mixtures can be mentioned.

  The metal or metal compound layer can be formed by a vacuum deposition method, an ion plating method, or a sputtering method, and among them, it is preferably formed by a vacuum deposition method. The thickness of these metal or metal compound layers is not particularly limited, but is preferably in the range of 30 to 150 nm. By setting the thickness of the metal or metal compound layer in the range of 30 to 150 nm, the reflectivity and glossiness are excellent, the performance as a metal pigment is improved, and the dispersion stability of the metal foil pieces is improved.

  The release resin layer in the composite pigment base material for producing the metal foil piece used in the present invention is an undercoat layer of the metal or metal compound layer, but improves the peelability from the sheet-like substrate surface. It is a peeling layer for making it. The resin used for this release resin layer is not particularly limited, but for example, polyvinyl alcohol, polyvinyl butyral, polyethylene glycol, polyacrylic acid, polyacrylamide, cellulose derivative, polyvinyl butyral, acrylic acid copolymer, or A modified nylon resin is preferred. A layer is formed by applying a solution of one or a mixture of two or more of the above resins and drying. The coating solution can contain additives such as a viscosity modifier.

  The release resin layer is applied by commonly used gravure coating, roll coating, blade coating, extrusion coating, dip coating, spin coating, or the like. After coating and drying, the surface is smoothed by calendaring if necessary. Although the thickness of the resin layer for peeling is not specifically limited, 0.5-50 micrometers is preferable, More preferably, it is 1-10 micrometers. By setting the thickness of the peeling resin layer to 0.5 to 50 μm, the amount as a dispersion resin is sufficient, and even when rolled, it is difficult to peel off at the interface with the pigment layer.

  Although it does not specifically limit as a sheet-like base material in the composite pigment base material for manufacturing the metal foil piece contained in the ink composition by this invention, Polytetrafluoroethylene, polyethylene, a polypropylene, a polyethylene terephthalate, a polyethylene naphthalate And a release film such as a polyamide film such as polyester film such as 66 nylon and 6 nylon, a polycarbonate film, a triacetate film, and a polyimide film. Preferable sheet-like base material includes polyethylene terephthalate or a copolymer thereof.

  Although the thickness of these sheet-like base materials is not specifically limited, 10-150 micrometers is preferable. If it is 10 μm or more, there is no problem in handleability in the process or the like, and if it is 150 μm or less, it is rich in flexibility and there is no problem in roll formation, peeling and the like.

  The metal or metal compound layer may be sandwiched between protective layers. Examples of the protective layer include a silicon oxide layer and a protective resin layer. Although a silicon oxide layer will not be specifically limited if it is a layer containing a silicon oxide, It is preferable to form from silicon alkoxides, such as tetraalkoxysilane, or its polymer by a sol-gel method. A silicon oxide layer coating film is formed by applying an alcohol solution in which the silicon alkoxide or a polymer thereof is dissolved and baking it.

  The protective resin layer is not particularly limited as long as it is a resin that does not dissolve in the dispersion medium, and examples thereof include those formed from polyvinyl alcohol, polyethylene glycol, polyacrylic acid, polyacrylamide, or a cellulose derivative. Among them, those formed from polyvinyl alcohol or cellulose derivatives are preferable. A layer obtained by applying an aqueous solution of one or a mixture of two or more of the above resins and performing drying or the like is formed. The coating solution can contain additives such as a viscosity modifier. The silicon oxide and the resin are applied by the same method as the application of the release resin layer.

  Although the thickness of the said protective layer is not specifically limited, The range of 50-150 nm is preferable. By setting the thickness of the protective layer in the range of 50 to 150 nm, the mechanical strength is sufficient, so that the pulverization / dispersion is easy, and it is difficult to peel off at the interface with the metal or metal compound layer.

  Further, a color material layer may be provided between the “protective layer” and the “metal or metal compound layer”. The color material layer is introduced to obtain an arbitrary colored composite pigment, and in addition to the metallic luster and glitter of the metal foil pieces contained in the ink composition according to the present invention, a color that can impart an arbitrary color tone and hue. If it can contain a material, it will not specifically limit. As the color material used for the color material layer, either a dye or a pigment may be used. Moreover, as a dye and a pigment, a well-known thing can be used suitably. In this case, the “pigment” used in the color material layer means a natural pigment, a synthetic organic pigment, a synthetic inorganic pigment, or the like defined in the field of general pigment chemistry. This is different from that processed into a laminated structure.

  Examples of inorganic pigments that can be used in the color material layer include carbon blacks (CI pigment black 7) such as furnace black, lamp black, acetylene black, and channel black, iron oxide, and titanium oxide. it can. Organic pigments include insoluble azo pigments, condensed azo pigments, azo lakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments. Polycyclic pigments, dye chelates (for example, basic dye chelates, acid dye chelates, etc.), dye rakes (basic dye rakes, acid dye rakes), nitro pigments, nitroso pigments, aniline black, daytime Examples thereof include a light fluorescent pigment. The above pigments can be used alone or in combination of two or more. Further, any pigment that is not described in the color index can be used as long as it is insoluble in the ink composition.

  As the black pigment, carbon black is preferable. Specific examples of carbon black include # 2300, # 900, HCF88, # 33, # 40, # 45, # 52, MA7, MA8, MA100, # 2200B manufactured by Mitsubishi Chemical, Raven 5750, 5250 , 5000, 3500, 1255, 700, etc., Regal 400R, 330R, 660R, Mogu L, 700, Monarch 800, 880, 900, 1000, 1100, 1300, manufactured by Cabot Corporation , 1400, etc. Color Black FW1, FW2V, FW18, FW200, Color Black S150, S160, S170, Printex 35, U, V, 140U, Special Black 6, 5 4A, same Etc. can be mentioned, may be used as these alone or in combination of two or more.

  Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 4, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 128, 129, 138, 150, 151, 154, 155, 180, 185, etc., preferably C.I. I. One or a mixture of two or more selected from the group consisting of CI Pigment Yellow 74, 109, 110, 128, and 138. Examples of magenta and light magenta pigments include C.I. I. Pigment Red, 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 15: 1, 112, 122, 123, 168, 184, 202, 209 and C.I. I. Pigment violet 19 and the like, preferably C.I. I. Pigment red 122, 202, 209, and C.I. I. One or a mixture of two or more selected from the group consisting of pigment violet 19.

  Examples of cyan and light cyan pigments include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 15:34, 16, 22, 60, and C.I. I. Bat blue 4, 60 and the like, preferably C.I. I. Pigment Blue 15: 3, 15: 4, and one or a mixture of two or more selected from the group consisting of 60. As pigments used in white ink, titanium dioxide, calcium carbonate, calcium sulfate, zinc oxide, barium sulfate, barium carbonate, silica, alumina, kaolin, clay, talc, clay, aluminum hydroxide, magnesium carbonate, white hollow resin emulsion Preferably, it is one or a mixture of two or more selected from the group consisting of these. In addition, the pigments of the respective colors can be mixed and used in order to adjust the color tone. For example, pigment black 7 and pigment blue 15: 3 can be mixed for the purpose of changing the color tone of reddish black to blue.

  The pigment that can be used in the color material layer preferably has an average particle diameter in the range of 10 to 500 nm, more preferably about 50 to 300 nm. Here, the average particle diameter is measured by a light scattering method, and can be measured using, for example, Microtrac UPA (Microtrac Inc.). Further, the content of the pigment used in the ink composition of the present invention may be appropriately determined according to the type of the ink composition such as the dark and light ink composition, but is 1.5 to 20% by weight in the ink composition. , Preferably 3 to 10% by weight.

  A method for forming the color material layer is not particularly limited, but it is preferable to form the color material layer by coating. Further, when the color material used in the color material layer is a pigment, it is preferable to further include a color material dispersion resin, and as the color material dispersion resin, polyvinyl butyral, an acrylic acid copolymer, or the like is preferable. In this case, the color material layer is prepared by dispersing or dissolving a pigment, a color material dispersing resin and other additives as necessary in a solvent, and forming a uniform liquid film by spin coating as a solution, followed by drying. It is preferable to prepare as a resin thin film. In the production of the composite pigment base material for producing the metal foil piece contained in the ink composition of the present invention, the above-mentioned color material layer and protective layer are both formed by coating in terms of work efficiency. preferable.

  As the composite pigment base material for producing the metal foil piece contained in the ink composition of the present invention, a layer structure having a plurality of sequential laminated structures of the release resin layer and the metal or metal compound layer is also possible. . At that time, the total thickness of the laminated structure composed of a plurality of metals or metal compound layers, that is, the metal or metal compound layer-exfoliation resin layer-metal or metal excluding the sheet-like base material and the exfoliation resin layer immediately above it. Metal compound layer (repeated) ... Release resin layer-The thickness of the metal or metal compound layer is preferably 5000 nm or less. When it is 5000 nm or less, even when the composite pigment base material is rolled up, it is difficult to cause cracking and peeling and is excellent in storage stability. In addition, when pigmented, it is excellent in glitter and preferable. Moreover, although the structure where the resin layer for peeling and the metal or metal compound layer were laminated | stacked one by one on both surfaces of the sheet-like base material surface is also mentioned, it is not limited to these.

  The metal foil pieces contained in the ink composition according to the present invention are peeled off from the sheet-like substrate and pulverized at the interface between the sheet-like substrate of the composite pigment base and the release resin layer. It can be obtained by miniaturization. The peeling treatment method is not particularly limited, but is a method by immersing the composite pigment raw material in a liquid, or performing ultrasonic treatment at the same time as immersing in the liquid. A method of performing pulverization is preferred. In the metal foil pieces obtained as described above, the release resin layer has a role of a protective colloid, and a stable dispersion can be obtained simply by performing a dispersion treatment in a solvent. In the ink composition using the metal foil piece, the resin derived from the peeling resin layer also has a function of imparting adhesiveness to a recording medium such as paper.

<Coloring pigment>
According to a preferred aspect of the present invention, there is provided an ink composition containing a color pigment together with the metal foil piece, or an ink composition containing only the color pigment without containing the metal foil piece. According to a more preferred embodiment of the present invention, there is provided an ink composition containing only the color pigment without including the metal foil piece. Examples of the pigment contained in the color pigment include the same pigments that can be used for the color material layer, and examples thereof include natural pigments, synthetic organic pigments, and synthetic inorganic pigments.

  As the inorganic pigment that can be used for the color pigment, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, channel black, iron oxide, titanium oxide, and the like can be used. . Organic pigments include insoluble azo pigments, condensed azo pigments, azo lakes and chelate azo pigments, phthalocyanine pigments, perylene and perinone pigments, anthraquinone pigments, quinacridone pigments, dioxane pigments, thioindigo pigments, isoindolinone pigments, and quinophthalone pigments. Polycyclic pigments, dye chelates (for example, basic dye chelates, acid dye chelates, etc.), dye rakes (basic dye rakes, acid dye rakes), nitro pigments, nitroso pigments, aniline black, daytime Examples thereof include a light fluorescent pigment. The above pigments can be used alone or in combination of two or more. Further, any pigment that is not described in the color index can be used as long as it is insoluble in the ink composition.

  As the black pigment, carbon black is preferable. Specific examples of carbon black include # 2300, # 900, HCF88, # 33, # 40, # 45, # 52, MA7, MA8, MA100, # 2200B manufactured by Mitsubishi Chemical, Raven 5750, 5250 , 5000, 3500, 1255, 700, etc., Regal 400R, 330R, 660R, Mogu L, 700, Monarch 800, 880, 900, 1000, 1100, 1300, manufactured by Cabot Corporation , 1400, etc. Color Black FW1, FW2V, FW18, FW200, Color Black S150, S160, S170, Printex 35, U, V, 140U, Special Black 6, 5 4A, same Etc. can be mentioned, may be used as these alone or in combination of two or more.

  Examples of yellow pigments include C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 4, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 128, 129, 138, 150, 151, 154, 155, 180, 185, etc., preferably C.I. I. One or a mixture of two or more selected from the group consisting of CI Pigment Yellow 74, 109, 110, 128, and 138. Examples of magenta and light magenta pigments include C.I. I. Pigment Red, 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 15: 1, 112, 122, 123, 168, 184, 202, 209 and C.I. I. Pigment violet 19 and the like, preferably C.I. I. Pigment red 122, 202, 209, and C.I. I. One or a mixture of two or more selected from the group consisting of pigment violet 19.

  Examples of cyan and light cyan pigments include C.I. I. Pigment blue 1, 2, 3, 15: 3, 15: 4, 15:34, 16, 22, 60, and C.I. I. Bat blue 4, 60 and the like, preferably C.I. I. Pigment Blue 15: 3, 15: 4, and one or a mixture of two or more selected from the group consisting of 60. As pigments used in white ink, titanium dioxide, calcium carbonate, calcium sulfate, zinc oxide, barium sulfate, barium carbonate, silica, alumina, kaolin, clay, talc, clay, aluminum hydroxide, magnesium carbonate, white hollow resin emulsion Preferably, it is one or a mixture of two or more selected from the group consisting of these. In addition, the pigments of the respective colors can be mixed and used in order to adjust the color tone. For example, pigment black 7 and pigment blue 15: 3 can be mixed for the purpose of changing the color tone of reddish black to blue.

  Like the pigment that can be used for the color material layer, the pigment that can be used for the color pigment preferably has an average particle diameter in the range of 10 to 500 nm, more preferably about 50 to 300 nm. is there. Here, the average particle diameter is measured by a light scattering method, and can be measured using, for example, Microtrac UPA (Microtrac Inc.). Further, the content of the pigment used in the ink composition of the present invention may be appropriately determined according to the type of the ink composition such as the dark and light ink composition, but is 1.5 to 20% by weight in the ink composition. , Preferably 3 to 10% by weight.

<Other ingredients>
The ink composition of the present invention preferably contains substantially no water. Here, “substantially free of water” means that a trace amount of water is contained at a contamination level or a level equivalent to this in a range that does not inhibit the dispersion of the metal foil pieces in addition to the case where water is not included at all. Including the case where it is included. The content of water contained in the ink composition of the present invention is preferably, for example, 0 to 0.1% by weight.

  The ink composition according to the present invention may contain a penetrant in addition to the above components.

  As the penetrant, glycol ethers having a latent heat of vaporization of 80 cal / g or less or a molecular weight of 170 or less can be suitably used.

  Specific examples of glycol ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-iso-propyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol mono-iso-butyl ether, ethylene glycol mono-tert -Butyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-propyl ether, diethylene glycol mono-iso-propyl ether, diethylene glycol mono-tert-butyl ether, triethylene glycol mono-n-butyl ether, Propylene glycol monomethyl ester Ter, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, propylene glycol mono-iso-propyl ether, propylene glycol mono-n-butyl ether, propylene glycol mono-tert-butyl ether, dipropylene glycol monomethyl ether, dipropylene Glycol monoethyl ether, dipropylene glycol mono-n-propyl ether, dipropylene glycol-iso-propyl ether, dipropylene glycol mono-n-butyl ether, dipropylene glycol mono-tert-butyl ether, 1-methyl-1-methoxybutanol These can be used, and these can be used as one kind or a mixture of two or more kinds.

Among the above glycol ethers, polyhydric alcohol alkyl ethers are preferred, and ethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether , Propylene glycol monobutyl ether, triethylene glycol monomethyl ether, or triethylene glycol mono-n-butyl ether is preferred.
Needless to say, some of the above-mentioned alkylene glycol monoalkyl ethers can also function as penetrants when added to the ink composition.
In addition, the glycol ethers as the penetrant may overlap with the alkylene glycol monoalkyl ether used from the viewpoint of suppressing the aggregation of the ink, but some glycol ethers have both effects. .

  The amount of the penetrant added to the ink composition of the present invention is preferably less than 30% by weight based on the ink composition. Penetration agents such as glycol ethers having a latent heat of vaporization of 80 cal / g or less or a molecular weight of 170 or less have a viscosity of the solvent itself higher than that of an alkylene glycol monoalkyl ether having a latent heat of vaporization of 80 cal / g or less and a molecular weight of 170 or less. Is expensive. Therefore, it is preferable that the content of the penetrant such as glycol ethers having a latent heat of evaporation of 80 cal / g or less or a molecular weight of 170 or less in the ink composition is less than 30% by weight, the viscosity of the ink can be suppressed.

  Examples of the fixing resin include acrylic resin, styrene-acrylic resin, rosin-modified resin, terpene resin, polyester resin, polyamide resin, epoxy resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer, polyvinyl butyral, polyvinyl alcohol. And polyurethane. Further, non-aqueous emulsion type polymer fine particles (NAD = Non Aqueous Dispersion) can also be used as the fixing resin. This is a dispersion in which fine particles such as a polyurethane resin, an acrylic resin, and an acrylic polyol resin are stably dispersed in an organic solvent. The fixing resin is preferably added in an amount of 0.1 to 10% by weight in the ink composition in order to further improve the fixability of the pigment to the recording medium.

  Further, as the fixing resin, the ink composition of the present invention may contain a fibrous resin. The fiber-based resin is not particularly limited as long as the effect of the present invention is exhibited, but a cellulose ester resin is preferable. Examples of the cellulose ester resin include resins such as cellulose acetate (CA), cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB), cellulose propionate (CP), and cellulose triacetate (CAT). Among these, cellulose acetate butyrate (CAB) resin (hereinafter sometimes referred to as “CAB resin”) is preferable. These fibrous resins can be used as viscosity modifiers. By using the CAB resin, an image having a clear glossiness can be formed.

  Although the said CAB resin is not specifically limited as long as there exists an effect of this invention, It is preferable to have a 16.5-48% butylated rate, and a 16.5-39% butylated rate is more preferable. When the CAB resin has a butylation ratio in this range, that is, 16.5% or more, the CAB resin can be dissolved in the organic solvent, and sufficiently exhibits a function as a viscosity modifier. Can do. In addition, when the butylated rate of the CAB resin is in this range, that is, 48% or less, the solubility of the CAB resin in the organic solvent does not become too high, so that a desired viscosity can be obtained and good. A metallic image having glossiness can be obtained.

  The weight average molecular weight of the CAB resin is preferably 60,000 to 90,000, and more preferably 70,000 to 80,000. By being in this range, a desired viscosity can be obtained.

  The addition amount of the CAB resin is preferably 0.01% by weight or more and 10% by weight or less, and more preferably 0.1% by weight or more and 5% by weight or less in the ink composition. When the addition amount of the CAB resin is within the above range, the fixability of the pigment to the recording medium can be improved.

  The ink composition of the present invention preferably contains at least one glycerin, polyalkylene glycol, or saccharide. The total amount of the one or more types of glycerin, polyalkylene glycol, or saccharide is preferably added in an amount of 0.1 to 10% by weight in the ink composition. With such a preferable configuration, it is possible to stabilize ink discharge and improve the image quality of the recorded matter while suppressing drying of the ink and preventing clogging.

The polyalkylene glycol is a linear polymer compound having a repeating structure of an ether bond in the main chain, and is produced, for example, by ring-opening polymerization of a cyclic ether. Specific examples of the polyalkylene glycol include polymers such as polyethylene glycol and polypropylene glycol, ethylene oxide-propylene oxide copolymers and derivatives thereof. As the copolymer, any copolymer such as a random copolymer, a block copolymer, a graft copolymer, and an alternating copolymer can be used. Preferable specific examples of the polyalkylene glycol include those represented by the following formula.
_{HO- (C n H 2n O)} m -H
(In the above formula, n represents an integer of 1 to 5, m represents an integer of 1 to 100)
In the above formula, (C _n H _2n O) _m may be one constant or a combination of two or more numbers within the range of the integer value n. For example, when n is 3, it is (C ₃ H ₆ O) _m , and when n is a combination of 1 and 4, it is (CH ₂ O—C ₄ H ₈ O) _m . Further, the integer value m may be one constant or a combination of two or more numbers within the range. For example, in the above example, when m is a combination of 20 and 40, it is (CH ₂ O) _20- (C ₂ H ₄ O) ₄₀ , and when m is a combination of 10 and 30, (CH ₂ O ) ₁₀ - _(a C ₄ H 8 _{O) 30.} Further, the integer values n and m may be arbitrarily combined within the above range.

  Examples of the saccharide include monosaccharides such as pentose, hexose, heptose, and octose; polysaccharides such as disaccharide, trisaccharide, and tetrasaccharide; or sugar alcohols that are derivatives thereof, reduced derivatives such as deoxyacid, aldonic acid, uronic acid, and the like. Examples include oxidized derivatives, dehydrated derivatives such as glycosene, amino acids, thiosugars, and the like. As the sugar alcohol, a crystalline sugar alcohol that is solid at room temperature is suitable. One or more selected from the group consisting of maltitol, sorbitol, xylitol, erythritol, trehalose, isotrehalose, neotrehalose, and sucrose are preferred, and selected from the group consisting of trehalose or isotrehalose, neotrehalose, and sucrose It is more preferable from a dry viewpoint that it further contains 1 type, or 2 or more types. Polysaccharides refer to sugars in a broad sense and include substances that exist widely in nature, such as alginic acid, dextrin, and cellulose.

  The ink composition of the present invention preferably contains at least one acetylene glycol surfactant and / or polyorganosiloxane surfactant. The surfactant is preferably added in an amount of 0.01 to 10% by weight based on the pigment content in the ink composition. By adopting such a suitable configuration, the wettability of the ink composition to the recording medium is improved, and quick fixability can be obtained. Preferred examples of the acetylene glycol surfactant include Surfynol 465, Surfynol 104 (both manufactured by Air Products and Chemicals, Inc.), Olphine STG, Olphine E1010 (manufactured by Nisshin Chemical Co., Ltd.), and the like. Polyorganosiloxane has a straight chain in which the side chain or terminal is a methyl group or a part of the side chain is a phenyl group or hydrogen group, and the side chain or terminal is an organic group (amino group, epoxy group, polyether group). Etc.). Examples include polydimethylsiloxane, polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, amino-modified polydimethylsiloxane, carboxyl-modified polydimethylsiloxane, carbinol-modified polydimethylsiloxane, and the like.

  Commercially available polyorganosiloxane surfactants may be used, such as Olfine PD-501, Olfine PD-502, Olfine PD-570 (all manufactured by Nissin Chemical Industry Co., Ltd.), etc. Can be used.

（式中、Ｒは水素原子またはメチル基を表し、ａは２〜１１の整数を表し、ｍは２〜５０の整数を表し、ｎは１〜５の整数を表す。）
で表される一種または二種以上の化合物を含んでなるか、または、上記式（Ｉ）の化合物において、Ｒが水素原子またはメチル基であり、ａが２〜１３の整数であり、ｍは２〜５０の整数であり、ｎは１〜５の整数である一種または二種以上の化合物を含んでなることがより好ましい。また、上記式（Ｉ）の化合物において、Ｒが水素原子またはメチル基であり、ａが２〜１３の整数であり、ｍは２〜５０の整数であり、ｎは１〜８の整数である一種または二種以上の化合物を含んでなることがより好ましい。あるいは、上記式（Ｉ）の化合物において、Ｒがメチル基であり、ａが６〜１８の整数、であり、ｍが０であり、ｎが１である一種または二種以上の化合物を含んでなることがより好ましい。このような特定のポリオルガノシロキサン系界面活性剤を使用することにより、記録媒体として印刷本紙に印刷した場合であっても、インクの凝集むらがより改善される。 Further, as the polyorganosiloxane surfactant, the following formula (I):

(In the formula, R represents a hydrogen atom or a methyl group, a represents an integer of 2 to 11, m represents an integer of 2 to 50, and n represents an integer of 1 to 5).
Or in the compound of the above formula (I), R is a hydrogen atom or a methyl group, a is an integer of 2 to 13, and m is More preferably, it is an integer of 2 to 50, and n comprises one or more compounds that are integers of 1 to 5. In the compound of the above formula (I), R is a hydrogen atom or a methyl group, a is an integer of 2 to 13, m is an integer of 2 to 50, and n is an integer of 1 to 8. More preferably, it comprises one or more compounds. Or in the compound of the said formula (I), R is a methyl group, a is an integer of 6-18, m is 0, n contains 1 type or 2 or more types of compounds. More preferably. By using such a specific polyorganosiloxane-based surfactant, even when printing is performed on printing paper as a recording medium, ink aggregation unevenness is further improved.

  In the compound of the above formula (I), a is an integer of 2 to 5, m is an integer of 20 to 40, n is an integer of 2 to 4, and a is an integer of 7 to 11. M is an integer of 30 to 50, n is an integer of 3 to 5, a is an integer of 9 to 13, m is an integer of 2 to 4, and n is an integer of 1 to 2 It is more preferable to use a certain compound or a compound in which a is an integer of 6 to 10, m is an integer of 10 to 20, and n is an integer of 4 to 8. By using such a compound, the unevenness of ink aggregation can be further improved.

  In the compound of the above formula (I), R is a hydrogen atom, a is an integer of 2 to 5, m is an integer of 20 to 40, and n is an integer of 2 to 4, Alternatively, it is more preferable to use a compound in which a is an integer of 7 to 11, m is an integer of 30 to 50, and n is an integer of 3 to 5. By using such a compound, it is possible to further improve the uneven aggregation and bleeding of the ink.

  In the compound of the above formula (I), R is a methyl group, a is an integer of 9 to 13, m is an integer of 2 to 4, and n is an integer of 1 to 2, Alternatively, it is more preferable to use a compound in which a is an integer of 6 to 10, m is an integer of 10 to 20, and n is an integer of 4 to 8. By using such a compound, it is possible to further improve the uneven aggregation and bleeding of the ink.

  Furthermore, in the compound of the above formula (I), it is more preferable to use a compound in which R is a methyl group, a is an integer of 6 to 12, m is 0, and n is 1. By using such a compound, it is possible to further improve the uneven aggregation and bleeding of the ink.

  Moreover, in the compound of the said formula (I), R is a hydrogen atom, a is an integer of 7-11, m is an integer of 30-50, n is an integer of 3-5, , R is a methyl group, a is an integer of 9 to 13, m is an integer of 2 to 4, n is an integer of 1 to 2, R is a methyl group, and a is 6 It is most preferable to use a mixture of a compound having an integer of 10 to 10, m being an integer of 10 to 20, and n being an integer of 4 to 8. By using such a compound, it is possible to further improve the uneven aggregation and bleeding of the ink.

The ink composition of the present invention is preferably one in which the above metal foil pieces are dispersed and contained in a liquid medium of a slightly water-soluble alkanediol and an alkylene glycol monoalkyl ether. In addition to the above liquid medium, the following liquid medium may be further used in the ink composition of the present invention. The liquid medium further used in the ink composition of the present invention may be aqueous or organic. However, from the viewpoint of ensuring the reliability of the ink, it should be organic. Is preferred. The organic liquid medium is preferably a polar organic solvent, for example, alcohols (for example, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, or fluorinated alcohol), ketones (for example, acetone, methyl ethyl ketone, or Cyclohexanone, etc.), carboxylic acid esters (eg, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, or ethyl propionate), or ethers (eg, diethyl ether, dipropyl ether, tetrahydrofuran, or Dioxane etc.) can be used. Other preferable organic solvents include, for example, a mixture of a diethylene glycol compound that is liquid at normal temperature and pressure and a dipropylene glycol compound that is liquid at normal temperature and pressure as described in WO 2002/055619. it can.

  In the case where an organic liquid medium is used, a nonionic polyoxyethylene derivative can also be included. The polyoxyethylene derivative is preferably a compound that is liquid at normal temperature and pressure. The polyoxyethylene derivative can impart re-solubility to the oil-based ink composition.

Examples of the polyoxyethylene derivatives include polyoxyethylene alkyl ethers such as polyoxyethylene cetyl ether (for example, Nissan Nonion P-208, manufactured by NOF Corporation), polyoxyethylene oleyl ether (for example, Nissan Nonion). E-202S, E-205S, manufactured by NOF Corporation), or polyoxyethylene lauryl ether (for example, Emulgen 106, 108, manufactured by Kao Corporation), polyoxyethylene alkylphenol ether, for example, polyoxyethylene octylphenol ether (for example, , Nissan Nonion HS-204.5, HS-206, HS-208, manufactured by NOF Corporation, sorbitan monoester, for example, sorbitan monocaprylate (for example, Nissan Nonion C) -08R, manufactured by NOF Corporation), or sorbitan monolaurate (for example, Nissan Nonion LP-20R, manufactured by NOF Corporation), polyoxyethylene sorbitan monoester, for example, polyoxyethylene sorbitan monostearate (for example, Nissan Nonion OT-221, manufactured by Nippon Oil & Fats Co., Ltd., polycarboxylic acid polymer activator (Floren G-700, manufactured by Kyoeisha Chemical Co., Ltd.), polyoxyethylene higher alcohol ether (for example, Emulgen 707, 709, Kao Corporation) Company), tetraglycenline oleate (for example, Poem J-4581, manufactured by Riken Vitamin Co., Ltd.), nonylphenol ethoxylate (for example, Adekatol NP-620, NP-650, NP-660, NP-675, NP-683) NP-68 , Manufactured by Asahi Denka Kogyo Co., Ltd.), aliphatic phosphate esters (for example, Adeka Coal CS-141E, TS-230E, manufactured by Asahi Denka Kogyo Co., Ltd.), sorbitan sesquiolate (for example, Sorgen 30, manufactured by Daiichi Kogyo Seiyaku Co., Ltd. ), Sorbitan monooleate (for example, Sorgen 40, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polyethylene glycol sorbitan monolaurate (for example, Sorgen TW-20, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), polyethylene glycol sorbitan monooleate (for example, , Sorgen TW-80, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). Furthermore, an acetylene glycol surfactant can be used as the polyoxyethylene derivative. Specific examples thereof include Surfynol 104, 82, 420, 440, 465, 485, or TG (all manufactured by Air Products and Chemicals, Inc.), Orphin STG, Orphine E1010 (all manufactured by Nisshin Chemical Co., Ltd.) ).

  In addition, as the polyoxyethylene derivative, other commercially available products can be used. Specific examples thereof include Nissan Nonion A-10R, A-13R (manufactured by Nippon Oil & Fats Co., Ltd.), Floren TG-740W. , D-90 (manufactured by Kyoeisha Chemical Co., Ltd.), Emulgen A-90, A-60 (manufactured by Kao Corporation), or Neugen CX-100 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

  In the case where an organic liquid medium is used, the content of the polyoxyethylene derivative in the ink composition of the present invention can be appropriately selected depending on the re-solubility to be imparted, but the pigment content in the ink composition Preferably it is 5-200 weight% with respect to quantity, More preferably, it is 30-120 weight%.

  When an organic liquid medium is used, the ink composition of the present invention can contain a dispersant. As the dispersant, any dispersant used in ordinary oil-based ink compositions, in particular, ink-jet recording oil-based ink compositions, can be used. Particularly, when the solubility parameter of the organic solvent is 8 to 11. It is preferable to use a dispersant that acts effectively. Commercially available products may be used as such dispersants. Specific examples thereof include polyester polymer compounds (Hinoact KF1-M, T-6000, T-7000, T-8000, T-8350P, T-8000E (manufactured by Takefu Fine Chemical Co., Ltd.), solsperse 20000, 24000, 32000, 32500, 33500, 34000, 35200 (manufactured by Avicia Co., Ltd.), disperbyk-161, 162, 163, 164, 166, 180, 190, 191, 192 (Bic Chemie), Floren DOPA-17, 22, 33, G-700 (Kyoeisha Chemical Co., Ltd.), Ajisper PB821, PB711 (Ajinomoto Co., Ltd.), LP4010, LP4050, LP4055, POLYMER400, 01,402,403,450,451,453 can be mentioned (manufactured by EFKA Chemicals, Inc.). In the ink composition of the present invention, the content of the dispersant can be appropriately selected depending on the pigment to be dispersed, but is preferably 5 to 200% by weight based on the content of the pigment in the ink composition. More preferably, it is 30 to 120% by weight.

  In the case where an organic liquid medium is used, the ink composition of the present invention can contain other additives contained in a normal oil-based ink composition. Such additives can include, for example, stabilizers (eg, antioxidants or UV absorbers), surfactants, and / or binder resins. As the antioxidant, for example, BHA (2,3-butyl-4-oxyanisole) or BHT (2,6-di-t-butyl-p-cresol) can be used, and as an ultraviolet absorber, For example, a benzophenone compound or a benzotriazole compound can be used. As the surfactant, any of anionic, cationic, amphoteric, or nonionic surfactants can be used. Furthermore, the viscosity of the oil-based ink composition of the present invention can be adjusted by the binder resin. The viscosity (viscosity at a temperature of 20 ° C.) of the oil-based ink composition of the present invention is, for example, 10 mPa · s, more preferably 5 mPa · s.

  The ink composition of the present invention can be prepared by a known conventional method. For example, first, after mixing a metal foil piece, a dispersant, and the liquid medium, a pigment dispersion is prepared by a ball mill, a bead mill, an ultrasonic wave, a jet mill or the like, and is prepared to have desired ink characteristics. . Subsequently, a binder resin, the liquid medium, and other additives (for example, a dispersion aid and a viscosity modifier) can be added with stirring to obtain a pigment ink composition. In addition, the composite pigment base may be sonicated in a liquid medium once to obtain a composite pigment dispersion, and then mixed with the necessary ink liquid medium. The ink composition may be directly subjected to ultrasonic treatment in an ink medium.

  The physical properties of the ink composition of the present invention are not particularly limited. For example, the surface tension is preferably 20 to 50 mN / m. When the surface tension is less than 20 mN / m, the ink composition may spread or ooze out on the surface of the inkjet recording printer head, making it difficult to eject ink droplets, and the surface tension is 50 mN / m. If it exceeds 1, the surface of the recording medium will not spread and good printing may not be possible.

Recording Method The ink composition according to the present invention is preferably used for inkjet recording, and can be applied to various inkjet recording systems. That is, an electric field control method that ejects ink using electrostatic attraction, a drop-on-demand method (or pressure pulse method) that ejects ink using the driving pressure of a piezo element, and a bubble due to high heat The present invention can be applied to various ink jet recording methods such as a bubble or thermal jet method in which ink is ejected using pressure generated by forming and growing.

  In the ink jet recording method using the ink composition according to the present invention, it is preferable to form an image using an ink jet head having a nozzle diameter of 30 μm or less. Moreover, it is preferable that ratio (average particle diameter / nozzle diameter) of the average particle diameter of the metal foil piece used for this invention and the nozzle diameter of an inkjet head is 0.15 or less.

  The ink jet recording apparatus usable in the present invention is not particularly limited as long as it can perform recording by ejecting ink droplets and attaching the droplets onto the recording medium. It is preferable to have a function capable of heating. Functions that can be heated include, for example, a print heater function that heats a recording medium by directly contacting a heat source, and irradiation with infrared rays and microwaves (electromagnetic waves having a maximum wavelength of about 2,450 MHz) without directly contacting the recording medium. Or a dryer function that blows warm air. The print heater function and the dryer function can be used independently or simultaneously. Thereby, the drying temperature at the time of printing can be adjusted.

Ink Set The ink set according to the present invention is preferably for ink jet recording, and comprises the above ink composition. The ink set may include one or a plurality of ink compositions according to the present invention, and may further include an ink set including one or more other ink compositions. Other ink compositions that may be included in the ink set according to the present invention include cyan, magenta, yellow, light cyan, light magenta, dark yellow, red, green, blue, orange, violet and other color ink compositions, black Examples thereof include an ink composition and a light black ink composition.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by these Examples.

Production of Aluminum Pigment Dispersion (1) On a PET film having a film thickness of 100 μm, a resin layer coating solution having the following composition was formed by spin coating, and then dried to form a resin thin film layer.

(Resin layer coating solution)
Sletsk BL-10
(Sekisui Chemical Co., Ltd. butyral resin) 3.0 wt%
Glycerin 2.0% by weight
IPA (isopropyl alcohol) remaining

(2) An aluminum vapor deposition layer having a film thickness of 70 nm was formed on the resin layer using a VE-1010 type vacuum vapor deposition apparatus (manufactured by Vacuum Device Inc.).
(3) A PET film having a laminate of a resin layer and an aluminum vapor deposition layer formed by the above method is simultaneously peeled, refined, and dispersed in an IPA using an ultrasonic disperser, and an aluminum pigment dispersion is obtained. Produced. The content of the metal foil piece (aluminum-containing) in the aluminum pigment dispersion obtained by this method was 5.0% by weight. For the organic solvent substitution step from isopropyl alcohol to triethylene glycol monomethyl ether, any known method such as a distillation substitution method or an ultrafiltration method may be used, but the distillation substitution method was used.

  In addition, a PET film having a laminate of a resin layer and an aluminum vapor deposition layer formed by the above method is directly immersed in triethylene glycol monomethyl ether, and an ultrasonic disperser (manufactured by ASONE, “VS-150”) is used. The metal pigment dispersion may be prepared by simultaneously performing peeling, miniaturization, and dispersion treatment, and performing an integrated ultrasonic dispersion treatment time for 12 hours.

Preparation of metal foil piece-containing ink composition Using the aluminum pigment dispersion prepared by the above method, metal foil piece-containing ink compositions having the compositions shown in Tables 1 to 6 below were prepared. In addition, the numerical value in the following Tables 1-6 represents content (weight%) in an ink. The polyorganosiloxane-based surfactant used here is the formula (I) in which R is a methyl group, a is an integer of 6 to 18, m is an integer of 0, and n is 1. In the compound which is an integer and the above formula (I), R is a hydrogen atom, a is an integer of 7 to 11, m is an integer of 30 to 50, and n is an integer of 3 to 5. A compound, and in the above formula (I), R is a methyl group, a is an integer of 9 to 13, m is an integer of 2 to 4, and n is an integer of 1 to 2. Is a surfactant. The acetylene glycol surfactant used is Surfynol 420 (manufactured by Nissin Chemical Industry Co., Ltd.).

Examples 9-16
Examples 9 to 16 were prepared in the same manner except that 1,2-octanediol of Examples 1 to 8 in Tables 1 and 2 was replaced with 1,8-octanediol (see Table 3).

Comparative Examples 1-8
Comparative Examples 1 to 8 were produced in the same manner except that the triethylene glycol monomethyl ether of Examples 1 to 8 in Tables 1 and 2 was replaced with diethylene glycol diethyl ether (see Table 4).

Comparative Examples 9-16
Comparative Examples 9 to 16 were prepared in the same manner except that 1,2-octanediol of Comparative Examples 1 to 8 was replaced with γ-butyrolactone (see Table 5).

Comparative Examples 17-24
In Comparative Examples 17 to 24, a metal foil piece-containing ink composition was prepared based on the composition described in Table 6 above, using the aluminum pigment dispersion prepared by the above method.

Evaluation of Film Fixability Each metal foil piece-containing ink composition obtained above was mounted on an ink cartridge of an ink jet printer (PX-G900, manufactured by Seiko Epson Corporation), and about 128 g / m ² of Lumirror S10 (100 micron thick). ) At a resolution of 1440 × 720 dpi. As the printing conditions at this time, the ink discharge amount was adjusted so that the dot weight would be 3 ng in the unidirectional recording method in which the resolution of 720 × 180 dpi is obtained by one drive of the recording head. At this time, the ink adhesion amount was approximately 3.1 mg / inch ² .
A: In the environment of 20 ° C. and humidity of 30%, the recorded matter obtained is left to dry for 3 minutes and then rubbed with a finger, so that ink does not adhere to the finger.
B: In an environment where the temperature is 40 ° C. and the humidity is 30%, the obtained recorded matter is left to dry for 3 minutes and then rubbed with a finger.
C: In the environment of 40 ° C. and humidity of 30%, the printed matter obtained was left to dry for 10 minutes and then rubbed with a finger.
In the condition of D: B, ink adheres to the finger.
The evaluation results were as shown in Table 7 below. As can be seen from Table 7, the ink composition containing 1,2-octanediol suppresses ink repelling on the film, or is in an aggregated state, as compared with the ink composition containing 1,8-octanediol. In order to suppress the occurrence of the ink, the ink does not become a ball and the surface area increases, so that it is considered that the drying efficiency is improved.

Unevenness of ink aggregation Each metal foil piece-containing ink composition obtained above is mounted on an ink cartridge of an ink jet printer (PX-G900, manufactured by Seiko Epson Corporation), and about 128 g / m ² of Lumirror S10 (100 micron thick). In addition, printing was performed at a resolution of 1440 × 720 dpi. As the printing conditions at this time, the ink discharge amount was adjusted so that the dot weight was 3 ng in the recording method in which the resolution was 720 × 180 dpi by one drive of the recording head.
The amount of ink deposited on the obtained recorded matter was 3.1 mg / inch ² . Ink aggregation unevenness was evaluated according to the following criteria.
A: Even in the bidirectional recording method, there is no aggregation unevenness.
B: In the bidirectional recording method, uneven aggregation occurs. However, the unidirectional recording method does not cause uneven aggregation.
C: Even in the unidirectional recording method, uneven aggregation occurs. The evaluation results are as shown in Table 7 below.

Evaluation of Clogging Recoverability The ink cartridge was removed from the printer and moved to the ink replacement position to remove the cap from the head. In this state, it was left in an environment of 40 ° C. and 30% humidity for 1 day. Thereafter, clogging recovery was evaluated by button cleaning.
A: No more clogged nozzles within 10 button cleanings.
B: After 10 button cleanings, clogged nozzles remained.
C: When the ink cartridge was removed, the plastic member joining the head and the ink cartridge was damaged. For this reason, evaluation was impossible.
The evaluation results were as shown in Table 7 below.

The recording surface of the recording of each ink composition obtained in the evaluation the film fixability evaluation of gloss, using gloss meter (MINOLTA MULTI GLOSS 268), measuring the gloss at tilt angle 20 °, or less The evaluation was performed according to the criteria.
A: Glossiness of 200 or more B: Glossiness of less than 200 Evaluation results were as shown in Table 7 below.

  The same evaluation results were obtained for the fiber-based resin, regardless of the type of CA: cellulose acetate resin, CAB: cellulose acetate butyrate resin, and CP: cellulose propionate resin.

Claims (9)

  An ink composition comprising a hardly water-soluble alkanediol having 7 to 10 carbon atoms and an alkylene glycol monoalkyl ether.   The ink composition according to claim 1, wherein the hardly water-soluble alkanediol is a poorly water-soluble 1,2-alkanediol having 7 to 10 carbon atoms.   The ink composition according to claim 1, wherein the poorly water-soluble alkanediol is 1,2-octanediol.   The ink composition according to claim 1, further comprising a metal foil piece.   The ink composition according to any one of Claims 1 to 4, wherein the alkylene glycol monoalkyl ether is triethylene glycol monomethyl ether.   The ink composition according to any one of claims 1 to 5, further comprising at least one kind of glycerin, polyalkylene glycol, or saccharide.   The ink composition according to claim 1, further comprising at least one acetylene glycol surfactant and / or polyorganosiloxane surfactant.   The ink composition according to claim 1, wherein the ink composition is substantially free of water.   An ink set comprising the ink composition according to claim 1.