JP7043844B2 - Liquid ink composition - Google Patents

Description

The present invention relates to a liquid ink composition that can be used as a laminated ink for flexible packaging. It is particularly useful as a gravure printing ink for front printing.

Gravure inks and flexographic inks are widely used for the purpose of imparting beauty and functionality to the printed material of a flexible packaging film. When a gravure-printed or flexo-printed object is used as a flexible packaging material for foods and sanitary goods, among packaging materials, the packaging material that touches the contents to prevent contact with the contents is used for product packaging. Front printing is performed by printing the design only on the outside of the packaging material without printing on the back side, which is the side.
The gravure printing ink composition for front printing is required to have film strength and various resistances because the ink film printed on the front side of the film substrate is directly rubbed by an external force or corrodes with other substances. To.

That is, adhesiveness to various film substrates, blocking resistance that does not adhere to each other when the front printing surface and the printing surface, or the front printing surface and the back surface of the film are in close contact with each other, on a vinyl chloride table cloth. PVC blocking resistance that does not adhere when the product is placed, alcohol resistance that does not peel off the pattern when alcohol adheres to the printed surface, organic solvent or oil adheres, in the food at the packaging stage It is desired to have oil resistance and the like so that the pattern does not melt or peel off when the oil component of the above adheres.
And while maintaining the above performance, it is excellent in halftone dot reproducibility without blurring the highlight points that hit the small halftone dots even in high-speed printing, and it is excellent that printing stains on non-printed parts without patterns are less likely to occur. It is desirable to have printability as well.
For example, an invention of a gravure ink composition using a urethane resin and a cellulose derivative (for example, Patent Documents 1 and 2), a surface printing gravure ink composition containing a polyurethane resin, a vinyl chloride vinyl acetate copolymer, rosin, and a chelate. (For example, Patent Documents 3 and 4) and an invention of a surface printing gravure ink composition using an ester-based resin and an ester-based dispersant (for example, Patent Document 5) have been made, but all of them have various resistances. It cannot be said that the above-mentioned printability is compatible with each other. Above all, it is not easy to achieve both heat seal resistance against heat seal, blocking resistance against vinyl chloride and printability in film bag making, which has been increasing in recent years. ..

Japanese Unexamined Patent Publication No. 2007-246822 Japanese Unexamined Patent Publication No. 2002-294128 Japanese Unexamined Patent Publication No. 2012-012597 Japanese Unexamined Patent Publication No. 2013-256551 Japanese Unexamined Patent Publication No. 2017-039896

The subject of the present invention is not only excellent various ink coating properties such as substrate adhesion to a substrate film, but also high heat resistance, blocking resistance against vinyl chloride, and high halftone dots in high-speed printing. Liquid ink compositions and liquid ink compositions that have excellent halftone dot reproducibility without blurring of light spots, have a glossy stamp surface, and are less likely to cause printing stains on non-printed areas without patterns. Regarding printed matter that is printed.

As a result of diligent research to solve the above-mentioned problems, the present inventors have contained a polyurethane resin (A) and a vitrified cotton (B) using a specific polyester polyol as a reaction raw material in a liquid ink composition. It has been found that it is effective to solve the problem that the polyester polyol is a liquid ink composition using a polycarboxylic acid having 7 or more carbon atoms and two or more carboxyl groups as a raw material.

That is, it is a liquid ink composition containing a polyurethane resin (A) and nitrocellulose (B) using a polyester polyol as a reaction raw material, wherein the polyester polyol has 7 or more carbon atoms and two or more carboxyl groups. The present invention relates to a liquid ink composition characterized by using a polycarboxylic acid as a raw material.

The present invention further relates to a liquid ink composition containing a colorant (C) and an organic solvent (D).

The present invention further relates to a liquid ink composition containing a chelate compound (E) and a plasticizer (F).

The present invention also relates to a liquid ink composition in which the polycarboxylic acid is sebacic acid and / or dimer acid.

The present invention further relates to a liquid ink composition containing 0.1 to 3.0% by mass of fatty acid amide (G) in the total amount of the composition.

The present invention also relates to a liquid ink composition in which the organic solvent (H) does not contain an organic solvent having no aromatic group.

Further, the present invention further relates to a liquid ink composition, wherein the organic solvent contains an alcohol (I) having a specific evaporation rate of 100 or less when the evaporation rate of butyl acetate is 100.

The present invention also relates to a printed matter obtained by printing the liquid ink composition.

According to the present invention, in addition to various excellent ink coating properties such as substrate adhesion to a substrate film, heat resistance, blocking resistance to vinyl chloride, and highlight points that hit small halftone dots even in high-speed printing. Prints liquid ink compositions and liquid ink compositions that have excellent halftone dot reproducibility without blurring, gloss on the stamp surface, and are less likely to cause printing stains on non-printed areas without patterns. It is possible to provide printed matter.

The present invention will be described in detail. The "inks" used in the following description all refer to "printing inks". Further, "parts" all indicate "parts by mass".

The present invention is a liquid ink composition containing a polyurethane resin (A) and nitrified cotton (B) using a polyester polyol as a reaction raw material, wherein the polyester polyol has 7 or more carbon atoms and has two carboxyl groups. It is a liquid ink composition characterized by using the above-mentioned polycarboxylic acid as a raw material.

The liquid ink composition of the present invention specifically comprises polyurethane resin (A) and nitrocellulose (B) with isopropyl alcohol, ethyl acetate, normal propyl acetate, methylcyclohexane, etc., water as necessary, and various additives. Is premixed using a dispersion stirrer. Water may be added to the organic solvent in advance to form a water-containing organic solvent, or a specific amount of water may be added separately. In the case of a varnish composition, the varnish composition can be obtained by adding various additives while stirring the solution with a dispersion stirrer and further stirring. In the case of an ink composition, an ink composition is obtained by adding the colorant (D) and sufficiently dispersing the colorant (D).

The polyurethane resin (A) used in the liquid ink composition of the present invention is obtained by reacting a polyol, a polyisocyanate, a chain extender, and if necessary, a monovalent active hydrogen compound.

The polyester polyol as a reaction raw material of the polyurethane resin (A) used in the liquid ink composition of the present invention is essential to use a polycarboxylic acid having 7 or more carbon atoms and two or more carboxyl groups as a raw material. It is obtained by reacting with a compound having two or more hydroxyl groups.
The polyester polyol can further increase the laminating strength by introducing an ester group to increase the polarity, but the raw material is a polycarboxylic acid having 7 or more carbon atoms and 2 or more carboxyl groups. Therefore, it is possible to have both appropriate flexibility and laminating strength.

Examples of the polycarboxylic acid having 7 or more carbon atoms and two or more carboxyl groups include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and anhydrides of these acids, pimelic acid, and sveric acid. , Azelaic acid, sebacic acid, dimer acid and other aliphatic dicarboxylic acids, trimellitic acid and its anhydrides and the like, benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid and anhydrides of these acids and the like. Can be used. These polybasic acids may be used alone or in combination of two or more. Above all, when sebacic acid or dimer acid is used, it is preferable in that adhesion to a wide variety of various film substrates and high laminating strength can be obtained, and these may be used alone or in combination.

As the polyester polyol, other polyvalent carboxylic acids may be used if necessary, and various known polyvalent carboxylic acids generally used for producing polyester polyols can be used, and one or two kinds can be used. The above may be used together. Examples thereof include adipic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid and the like.

In addition, as global awareness of environmental issues has increased in recent years, attention has been focused on raw materials derived from biomass resources such as plants instead of petroleum-derived raw materials that affect global warming, and it is also possible to use these raw materials. It is possible. Examples of the polyvalent carboxylic acid derived from the biomass resource include succinic acid and anhydrous succinic acid.

Examples of the compound having two or more hydroxyl groups include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and tri. Glycols such as ethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol; 2-methyl-1,5-pentanediol, 3-methyl-1, 5-pentanediol, 1,2-butanediol, 1,3-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 2-methyl-1,3-propane Diol, neopentane glycol, 2-isopropyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3- Glycols with branched structures such as hexanediol, 2-ethyl-1,6-hexanediol, 3,5-heptanediol, 2-methyl-1,8-octanediol; glycerin, trimethylolpropane, trimethylolethane, penta Ellisritol, sorbitol and the like can be used. These compounds may be used alone or in combination of two or more.

Further, as with the polyvalent carboxylic acid, it is also possible to use a raw material derived from a biomass resource such as a plant for a compound having two or more hydroxyl groups. Examples of the compound having two or more hydroxyl groups derived from biomass resources include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, and glycerin.

The number average molecular weight of the polyester polyol is preferably in the range of 500 to 8,000, more preferably in the range of 800 to 7,000, and even more preferably in the range of 900 to 6,000. ..
In the present invention, the number average and the weight average molecular weight show the values measured under the following conditions by the gel permeation chromatography (GPC) method.

Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation)
Column: The following columns manufactured by Tosoh Corporation were connected in series and used.
"TSKgel G5000" (7.8 mm ID x 30 cm) x 1 "TSKgel G4000" (7.8 mm ID x 30 cm) x 1 "TSKgel G3000" (7.8 mm ID x 30 cm) x 1 This "TSKgel G2000" (7.8 mm ID x 30 cm) x 1 Detector: RI (Differential Refractometer)
Column temperature: 40 ° C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL / min Injection amount: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

[Standard polystyrene]
"TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

Further, it is more preferable that the polyether polyol is contained in the range of 1 to 40% by mass with respect to the polyurethane resin (A) as a constituent component of the polyurethane resin (A). As the polyether polyol, various known ether polyols generally used for producing a polyurethane resin can be used, and one kind or two or more kinds may be used in combination. Examples thereof include polyether polyols of polymers such as ethylene oxide, propylene oxide and tetrahydrofuran, or copolymers. When the content of the polyether polyol is 1% by mass or more with respect to 100% by mass of the polyurethane resin (A), the solubility of the urethane resin in a ketone, ester, or alcohol-based solvent is good, and the solvent of the ink film is also good. The resolubility in the printed matter is unlikely to decrease, and the tone reproducibility of the printed matter is unlikely to deteriorate. Further, if it is 40% by mass or less, the blocking resistance is unlikely to decrease.

Further, it is more preferable that the number average molecular weight of the polyether polyol is 100 to 3500. When the number average molecular weight of the polyether polyol is 100 or more, the film of the polyurethane resin (A) does not become hard and the adhesiveness to the polyester film does not easily decrease. When the number average molecular weight is 3500 or less, the tendency of the polyurethane resin (A) to become brittle can be suppressed, and the blocking resistance of the ink film tends to be difficult to decrease.

As the combined polyol used as necessary for the polyurethane resin (A) used in the liquid ink composition of the present invention, various known polyols generally used for producing a polyurethane resin can be used, and one type thereof. Alternatively, two or more types may be used in combination. For example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2butyl-1,3-propanediol, 1,3-butanediol. , 1,4-Butandiol, Neopentyl Glycol, Pentandiol, 3-Methyl-1,5 Pentandiol, Hexadiol, Octanediol, 1,4-Butindiol, 1,4-butylenediol, Diethylene Glycol, Triethylene Glycol , Dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, pentaeslitol and other saturated or unsaturated low molecular weight polyols. And / or low molecular weight polyols (1) derived from biomass resources, these low molecular weight polyols (1), adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malon. Dehydration condensation of polyvalent carboxylic acids such as acids, glutaric acid, pimelli acid, speric acid, azelaic acid, sebacic acid, trimellitic acid, pyromellitic acid or their anhydrides and / or polyvalent carboxylic acids derived from biomass resources. Alternatively, polyester polyols obtained by polymerization (2); polyester obtained by ring-opening polymerization of cyclic ester compounds such as polycaprolactone, polyvalerolactone, and lactones such as poly (β-methyl-γ-valerolactone). Polycols (3); Polycarbonate polyols (4) obtained by reacting the low molecular weight polyols (1) with, for example, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgen, etc .; Polybutadiene glycols (5); Bisphenol Glycols obtained by adding ethylene oxide or propylene oxide to A (6); one or more hydroxyethyls, hydroxypropulate acrylates, acrylic hydroxybutyls, etc., or their corresponding methacrylic acid derivatives, etc. in one molecule. And, for example, acrylic polyol (7) obtained by copolymerizing with acrylic acid, methacrylic acid or an ester thereof.

Examples of the diisocyanate compound used in the polyurethane resin (A) in the liquid ink composition of the present invention include various known aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates generally used for producing polyurethane resins. Be done. For example, 1,3-phenylenedis isocyanate, 1,4-phenylenedi isocyanate, 1-methyl-2,4-phenylenedi isocyanate, 1-methyl-2,6-phenylenediisocyanate, 1-methyl-2,5-phenylenediisocyanate, 1 -Methyl-2,6-phenylene diisocyanate, 1-methyl-3,5-phenylenedi isocyanate, 1-ethyl-2,4-phenylenedi isocyanate, 1-isopropyl-2,4-phenylenediisocyanate, 1,3-dimethyl-2 , 4-Hexamethylene diisocyanate, 1,3-dimethyl-4,6-phenylenediisocyanis, 1,4-dimethyl-2,5-phenylenediisocyanate, diethylbenzene diisocyanate, diisopropylbenzene diisocyanate, 1-methyl-3,5-diethylbenzene diisocyanate, 3-Methyl-1,5-diethylbenzene-2,4-diisocyanate, 1,3,5-triethylbenzene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 1-methyl -Naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate, 1,1-dinaphthyl-2,2'-diisocyanate, biphenyl-2,4'-diisocyanate, biphenyl-4 , 4'-Diisocyanate, 3-3'-dimethylbiphenyl-4,4'-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, diphenylmethane-2,4-diisocyanate and other aromatic polyisocyanes Texamethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexamethylene diisocyanate, 1,4-cyclohexamethylene diisocyanate, 1,3-di (isocyanis). Methyl) cyclohexane, 1,4-di (hexamethylene) cyclohexane, lysine diisocyanis, isophoron diisocyanis, 4,4'-dicyclohexamethylene diisocyanate, 2,4'-dicyclohexammethane diisocyanate, 2,2'-dicyclohexammethane diisocyanis, 3, 3'-dimethyl-4,4'-dicyclohexamethylene Aliphatic compounds such as diisocyanate or alicyclic polyisocyanates can be used. These polyisocyanates may be used alone or in combination of two or more. Among these, an aliphatic polyisocyanate and / or an alicyclic polyisocyanate is preferably used from the viewpoint of obtaining appropriate flexibility, and isophorone diisocyanate or hexamethylene diisocyanate is used from the viewpoint of further improving the adhesive strength. Is more preferable.

Examples of the chain extender used in the polyurethane resin (A) in the liquid ink composition of the present invention include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, and dicyclohexylmethane-4,4'-diamine. In addition, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2- Amines having a hydroxyl group in the molecule, such as hydroxypyrropyrethylenediamine, di-2-hydroxypyrropyrethylenediamine, and di-2-hydroxypropylethylenediamine, can also be used. These chain extenders can be used alone or in admixture of two or more.
Further, a monovalent active hydrogen compound can also be used as a terminal blocking agent for the purpose of stopping the reaction. Examples of such compounds include dialkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol. Further, especially when it is desired to introduce a carboxyl group into the polyurethane resin, amino acids such as glycine and L-alanine can be used as a reaction terminator. These terminal blockers can be used alone or in admixture of two or more.

The polyurethane resin (A) used in the liquid ink composition of the present invention is obtained by reacting a polyol, a polyisocyanate, a chain extender, and if necessary, a monovalent active hydrogen compound. For example, a polyester polyol and a combined polyol and a diisocyanate compound are reacted at a ratio of an excess of isocyanate groups to obtain a prepolymer having a terminal isocyanate group, and the obtained prepolymer is placed in a suitable solvent, that is, a solvent for liquid ink. Ester solvents such as ethyl acetate, propyl acetate and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; alcohol solvents such as methanol, ethanol, isopropyl alcohol and n-butanol; toluene, A hydrocarbon solvent such as xylene, methylcyclohexane, ethylcyclohexane; or a two-step method of reacting with a chain extender and / or terminal blocker in a mixed solvent thereof, or a polyester polyol and a combined polyol, a diisocyanate compound, It is produced by a one-step method in which a chain extender and / or a terminal sealant are reacted at once in a suitable solvent among the above. Among these methods, in order to obtain a uniform polyurethane resin (A), the two-step method is preferable. Further, when the polyurethane resin (A) is produced by the two-step method, the total (equivalent ratio) of the amino groups of the chain extender and / or the terminal blocker shall be 1 / 0.9 to 1.3. It is preferable to react with. When the equivalent ratio of isocyanate group to amino group is less than 1 / 1.3, the chain extender and / or terminal blocker remain unreacted, the polyurethane resin turns yellow, and the odor after printing is generated. It may occur.

The weight average molecular weight of the polyurethane resin (A) thus obtained is preferably in the range of 10,000 to 100,000, more preferably in the range of 15,000 to 95,000. When the weight average molecular weight of the polyurethane resin (A) is 10,000 or more, the blocking resistance, the strength of the printing film, the oil resistance, etc. of the obtained ink composition are unlikely to decrease, and when it is 100,000 or less, the obtained ink composition is obtained. The viscosity of the ink composition to be obtained does not become too high, and the gloss of the printing film can be easily maintained. The weight average molecular weight of the polyurethane resin (A) indicates a value obtained by measuring in the same manner as the number average molecular weight of the polyester polyol.
The content of the polyurethane resin (A) used in the liquid ink composition of the present invention with respect to the total amount of the composition is 4% by mass or more with respect to the total amount of the composition from the viewpoint of sufficiently adhering the ink to the printed matter. From the viewpoint of appropriate ink viscosity and work efficiency during ink production / printing, it is preferably 25% by mass or less, and more preferably 6 to 15% by mass.

Further, in the liquid ink composition of the present invention, nitric acid cotton (B) is indispensable in addition to the polyurethane resin (A).

By adding the nitrocellulose (B), high dispersibility of the pigment can be obtained. Therefore, when used as a gravure printing ink for front printing, the heat resistance and oil resistance of the printing ink coating film can be improved. It is suitable.
The nitricized cotton (B) preferably has a nitrogen content of 10 to 13% by mass and an average degree of polymerization of 30 to 500, and more preferably has a nitrogen content of 10 to 13% by mass and an average degree of polymerization of 45 to 290. The amount of the nitrocellulose (B) added is preferably 0.05 to 10% by mass with respect to the solid content of the ink. More preferably, it is 0.1 to 3% by mass.

The colorant (C) used in the liquid ink composition of the present invention may be either a color pigment or a white pigment. If a white pigment is added, it can also be used as a white ink corresponding to the background of a pattern, for example, for example, front printing and gravure printing. If these pigments are not added, it can also be used as an overcoat varnish.

Examples of the coloring pigment used in the liquid ink composition of the present invention include organic pigments and dyes used in general inks, paints, recording agents and the like. Organic pigments include azo-based, phthalocyanine-based, anthraquinone-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindoleinone-based, quinophthalone-based, azomethine-azo-based, dictopyrrolopyrrole-based, and isoindoline-based. Pigments can be mentioned.

As a color index name,
C. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 42, 74, 83;
C. I. Pigment Orange 16;
C. I. Pigment Red 5, 22, 38, 48: 1, 48: 2, 48: 4, 49: 1, 53: 1, 57: 1, 63: 1, 81, 101;
C. I. Pigment Violet 19, 23;
C. I. Pigment Blue 23, 15: 1, 15: 3, 15: 4, 17: 1, 18, 27, 29
C. I. Pigment Green 7, 36, 58, 59;
C. I. Pigment Black 7;
C. I. Pigment White 4, 6, 18 and the like.

For indigo ink, C.I. I. Pigment Blue 15: 3 (copper phthalocyanine), yellow ink is C.I. from the viewpoint of cost and light resistance. I. Pigment Yellow83, C.I. for red ink. I. It is preferable to use Pigment Red 57: 1. It is preferable to use carbon black for black ink, aluminum for gold and silver ink, and mica (mica) for pearl ink from the viewpoint of cost and coloring power. Although aluminum is in the form of powder or paste, it is preferable to use it in the form of paste from the viewpoint of handleability and safety, and whether to use reefing or non-reefing is appropriately selected from the viewpoint of brightness and concentration.

Examples of the white pigment used in the liquid ink composition of the present invention include titanium oxide, zinc sulfide, lead white, zinc flower, lithobon, antimony white, basic lead sulfate, basic lead silicate, and barium sulfate. , Calcium carbonate, gypsum, silica, etc.
The average particle size of the pigment is preferably in the range of 10 to 200 nm, more preferably about 50 to 150 nm.
The amount of the coloring pigment added is preferably in the range of 1 to 20% by mass of the total amount of the ink in order to obtain a sufficient image density and light resistance of the printed image.

The organic solvent used in the liquid ink composition of the present invention is not particularly limited, and is, for example, aromatic hydrocarbons such as toluene, xylene, Solbesso # 100 and Solbesso # 150, hexane, methylcyclohexane, heptane, octane, and the like. Examples thereof include aliphatic hydrocarbon-based solvents such as decane, and various ester-based organic solvents such as methyl acetate, ethyl acetate, isopropyl acetate, normal propyl acetate, butyl acetate, amyl acetate, ethyl formate, and butyl propionate. Also, as water-mixable organic solvents, alcohol-based solvents such as methanol, ethanol, propanol, butanol, and isopropyl alcohol, ketone-based solvents such as acetone, methyl ethyl ketone, and cyclohaxanone, ethylene glycol (mono, di) methyl ether, and ethylene glycol (mono, di) ethyl. Ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono, di) methyl ether, diethylene glycol (mono, di) ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono, di) Examples thereof include various glycol ether-based organic solvents such as di) methyl ether, propylene glycol (mono, di) methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol (mono, di) methyl ether. These can be used alone or in combination of two or more.

Above all, it is preferable to contain an alcohol which does not contain an aromatic hydrocarbon-based organic solvent and has a specific evaporation rate of 100 or less when the evaporation rate of butyl acetate is 100.
By containing an alcohol having a specific evaporation rate of 100 or less, it is possible to maintain the highlight transition property with a halftone dot area of 10% or less and maintain the highlight improvement.
The mechanism is as follows. First of all,
1) After the ink is transferred to the film, about half of the ink remains in the cell of the gravure plate.
2) The solvent contained in the remaining ink volatilizes until it comes into contact with the ink in the ink pan again, and the ink becomes semi-dry. Furthermore, since the solvent volatilizes from the solvent having a high evaporation rate, the solvent having a slow volatilization rate remains in the ink pan.
3) At this time, if a solvent having high resin solubility remains, the semi-dry ink is redissolved when it comes into contact with the ink again to prevent the ink from solidifying in the cell.
Since the volatilization rate of a general-purpose alcohol having a specific evaporation rate of more than 100 when the evaporation rate of butyl acetate is 100 is high, the above mechanism tends to be difficult to function.
Secondly, alcohol having a specific evaporation rate of 100 or less when the evaporation rate of butyl acetate is 100 has a low ratio of hydroxyl groups (alcohol groups) in one molecule of alcohol, so that the solubility of the polyurethane resin is improved. It tends to increase.

In terms of work hygiene during printing and harmfulness of packaging materials, use ethyl acetate, propyl acetate, isopropanol, normal propanol, etc., and do not use aromatic solvents such as toluene or ketone solvents such as methyl ethyl ketone. Is more preferable.
Above all, a mixed solution of isopropyl alcohol / ethyl acetate / normal propyl acetate / methylcyclohexane is more preferable from the viewpoint of solubility in polyurethane resin and nitrified cotton. Further, glycol ethers can be added as long as it is less than 10% by mass of the total amount of the composition for drying adjustment.

Further, the liquid ink composition of the present invention may contain the chelate compound (E) and the plasticizer (F).

When the liquid ink composition of the present invention is used as a front-printing gravure ink, the ink film is exposed to the outside because it is printed on the front side of the packaging material, and is in direct contact with various substances. Therefore, in addition to the adhesion of the base material to the film, tough film physical properties such as heat resistance and oil resistance are required. In particular, in recent years, there has been a demand for printing inks having high heat resistance to heat sealing during film bag making and oil resistance to oil contained in foods.
Therefore, in the liquid ink composition of the present invention, it is preferable to add a chelate cross-linking agent in order to secure the physical characteristics of the film, and a chelate-type metal organic compound for the purpose of improving the cohesive force is preferable. As the metal chelate compound, an organic titanium-based compound, an organic zirconium-based compound, or an organoaluminum-based compound can be used. If a chelate-type metal-organic compound is used, the cross-linking reaction is completed without heating, while a stable cross-linking reaction is obtained in which hydrolysis at room temperature is unlikely to occur, especially when amine is present in the molecule. The effect is great.

The titanium chelate has a Ti—OC bond in one molecule, and by having this alkoxy group, it has a role of strengthening the intramolecular or intramolecular cross-linking bond of the resin. Examples of the titanium chelate include titanium alkoxide and titanium acylate. Examples of the titanium alkoxide include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, tetramethyl titanate, and tetrastearyl titanate, as well as triethanolamine titanate, titanium acetyl acetate, and titanium ethyl acet acetate. , Titanium lactate, octylene glycol titanate, titanium tetraacetyl acetate, titanium phosphate compound and the like. Among the organic titanium compounds, titanium phosphate compounds and titanium acetyl acetate are preferable. Examples of commercially available products include titanium TAA chelating agents (manufactured by BORICA): titanium acetylacetonate CAS: 17927-27-9 and the like. The blending amount of the chelate cross-linking agent is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 3.0% by mass, based on the total amount of the composition.

Further, in the liquid ink composition of the present invention, a plasticizer (F) may be added in order to enhance the fluidity, adhesiveness, and abrasion resistance of the composition. In the case of a polymer such as a polyurethane resin, by adding a plasticizer (F), thickening can be suppressed, and the flexibility and flexibility of the ink-dried film after printing can be maintained.
Examples of the plasticizer (F) include fatty oils such as castor oil, phthalates such as dioctylphthalate, phosphate esters, fatty acid esters such as adipic acid esters and sebacic acid esters, polyesters, and epoxys. Examples thereof include epoxy systems such as chemical vegetable oils, citrate esters such as tributyl acetylcitrate, and sulfonic acid amide systems such as N-butylbenzene sulphonamide and N-ethyltoluene sulphonamide. Of these, citric acid esters, epoxidized vegetable oils, phosphoric acid esters and sulfonic acid amides are preferable.
The blending amount of the plasticizer (F) is preferably 0.01 to 10.0% by mass, more preferably 0.1 to 5.0% by mass, and 0.5 to 3.0% of the total amount of the composition. It is more preferable if it is by mass%. These plasticizers (F) may be used alone or in combination of two or more.

Further, in the liquid ink composition of the present invention, fatty acid amide (G) is preferably added in the range of 0.1 to 3.0% by mass, preferably 0.5 to 2.0% by mass, based on the total amount of the composition. Is more preferable. If the content is less than 0.1% by mass, the PVC blocking resistance may be lowered, and if it is 3.0% by mass or more, the oil resistance tends to be lowered.
The fatty acid amide (G) used in the liquid ink composition of the present invention may be a very general one which is a polycondensate of a polycarboxylic acid such as a polymerized fatty acid or various vegetable fatty acids and a polyamine. Examples of the polymerized fatty acid include dimer acid and hydrogenated dimer acid.
The various vegetable fatty acids may be any of tall oil fatty acids, palm oil fatty acids, coconut oil fatty acids, soybean oil fatty acids, cocoa fatty acids, rice bran fatty acids, and mixed fatty acids of these natural fats and oils as reaction raw materials.

The fatty acid amide (G) is preferably a polyamide resin having a number average molecular weight of 500 to 10,000, and more preferably 1,000 to 10,000.
If the number average molecular weight of the polyamide resin is less than 500, the PVC blocking resistance tends to decrease, and if it is 10,000 or more, the ink stability and oil resistance tend to decrease.

The fatty acid amide (G) mainly contains a polymerized fatty acid, an acid component that may partially contain an aliphatic, alicyclic and aromatic dicarboxylic acid or an aliphatic monocarboxylic acid, and mainly an aliphatic or alicyclic. It may be a reaction of a group, an aromatic fatty acid and an aromatic polyamine alone or a mixture thereof, and an amine component which may partially contain primary and secondary monoamines.
The polymerized fatty acid is obtained by polymerizing an unsaturated fatty acid having 16 to 22 carbon atoms or an ester thereof, and includes a monobasic fatty acid, a dimerized polymerized fatty acid, a trimerized polymerized fatty acid and the like.

Examples of the aliphatic dicarboxylic acid include succinic acid, maleic acid, adipic acid, dimer acid, and azelaic acid.
Examples of the alicyclic dicarboxylic acid include cyclohexanedicarboxylic acid, and examples of the aromatic dicarboxylic acid include isophthalic acid and terephthalic acid.
Further, examples of the aliphatic monocarboxylic acid include acetic acid, stearic acid, oleic acid, linoleic acid, palmitic acid, propionic acid and the like.

Further, as the polyamine which is an amine component, the aliphatic diamines such as ethylenediamine, propylenediamine and hexamethylenediamine, the aliphatic polyamines such as diethylenetriamine and triethylenetetramine are the alicyclic diamines such as cyclohexylene diamine and isophoronediamine. Examples thereof include xylylene diamine, which is an aromatic aliphatic diamine, and phenylenediamine and diaminodiphenylmethane, which are aromatic diamines.
Examples of the primary and secondary monoamines include mono- and di-alkylamines such as butylamine, octylamine and diethylamine, mono-propanolamines such as monoethanolamine, monopropanolamine, diethanolamine and dipropanolamine, and di-alkanolamines. be able to.
Further, if a polyamide resin having a hydroxyl group in the molecule using alkanolamine as a primary or secondary monoamine component is used, the reactivity with the chelating agent tends to be further increased, and the hydroxyl value in that case is 0.5 to. It is preferably in the range of 10.

Further, from the viewpoint of high-speed printing suitability, it is preferably 20% by mass or less with respect to the total amount of the above-mentioned polyurethane resin and cellulosic resin, and further preferably 10% by mass or less if the PVC blocking resistance can be maintained. ..

The liquid ink composition of the present invention is preferably added with a fatty acid amide (G) and used in combination with a polyurethane resin because heat resistance, oil resistance and vinyl chloride blocking resistance can be improved.
Examples of the fatty acid amide (G) include saturated fatty acid amides, unsaturated fatty acid amides, and modified fatty acid amides. Among them, the use of modified fatty acid amides is resistant to vinyl chloride on a soft vinyl chloride sheet used for table cloths. It is particularly preferable to improve the blocking property, and specifically, lauric acid amide (weight average molecular weight 199.3 CAS No. 1120-16-7) or the like is preferable.

Examples of the resin used in combination with the liquid ink composition of the present invention as needed include the polyurethane resin and resins other than nitrified cotton, for example, vinyl chloride-vinyl acetate copolymer resin, chlorinated polypropylene resin, and ethylene-acetic acid. Vinyl copolymer resin, vinyl acetate resin, polyamide resin, acrylic resin, polyester resin, alkyd resin, polyvinyl chloride resin, rosin resin, rosin-modified maleic acid resin, ketone resin, cyclized rubber, rubber chloride, butyral, petroleum Resin and the like can be mentioned. The combined resin can be used alone or in combination of two or more. The content of the combined resin is preferably 1 to 25% by weight, more preferably 2 to 15% by weight, based on the total weight of the ink.

The present invention may further include a combined resin, extender pigment, pigment dispersant, leveling agent, defoaming agent, wax, plasticizer, infrared absorber, ultraviolet absorber, fragrance agent, flame retardant and the like, if necessary. ..

In order to stably disperse the pigment in the organic solvent, the resin alone can be dispersed, but a dispersant can also be used in combination to stably disperse the pigment. As the dispersant, a surfactant such as anionic, nonionic, cationic or amphoteric can be used. For example, a comb-shaped structure polymer compound obtained by adding polyester to polyethyleneimine, an alkylamine derivative of an α-olefin maleic acid polymer, or the like can be mentioned. Specific examples thereof include the Sol Spurs series (ZENECA), the Azisper series (Ajinomoto), and the Homogenol series (Kao). Further, BYK series (Big Chemie), EFKA series (EFKA) and the like can also be used as appropriate. The dispersant is preferably contained in the ink in an amount of 0.05% by weight or more based on the total weight of the ink from the viewpoint of storage stability of the ink and 5% by weight or less from the viewpoint of laminating suitability, and more preferably 0. It is in the range of 1 to 2% by weight.

The liquid ink composition of the present invention can be produced by dissolving and / or dispersing a resin, a colorant, or the like in an organic solvent. Specifically, it is possible to produce a pigment dispersion in which a pigment is dispersed in an organic solvent with a polyurethane resin, and to produce an ink by blending the obtained pigment dispersion with another compound or the like as necessary. can.

The particle size distribution of the pigment in the pigment dispersion is adjusted by appropriately adjusting the size of the crushed media of the disperser, the filling rate of the crushed media, the dispersion treatment time, the discharge rate of the pigment dispersion, the viscosity of the pigment dispersion, and the like. be able to. As the disperser, generally used, for example, a roller mill, a ball mill, a pebble mill, an attritor, a sand mill and the like can be used.
If the ink contains air bubbles or unexpectedly coarse particles, it is preferable to remove them by filtration or the like in order to deteriorate the quality of the printed matter. As the filter, a conventionally known one can be used.

The viscosity of the ink produced by the above method may be in the range of 10 mPa · s or more from the viewpoint of preventing the pigment from settling and appropriately dispersing, and 1000 mPa · s or less from the viewpoint of workability efficiency during ink production and printing. preferable. The viscosity is a viscosity measured at 25 ° C. with a B-type viscometer manufactured by Tokimec.
The viscosity of the ink can be adjusted by appropriately selecting the type and amount of the raw material used, for example, a polyurethane resin, a colorant, an organic solvent, and the like. Further, the viscosity of the ink can be adjusted by adjusting the particle size and the particle size distribution of the pigment in the ink.

The plastic film that can be used as a base material is not particularly limited, and is, for example, a polyamide resin such as Ny6, nylon 66, or nylon 46, polyethylene phthalate (PET), polyethylene naphthalate, polytrimethylene terephthalate, or polytrimethylene naphthalate. Biodecomposition typified by polyester resins such as polybutylene terephthalate and polybutylene naphthalate, polyhydroxycarboxylic acids such as polylactic acid, and aliphatic polyester resins such as poly (ethylene succinate) and poly (butylene succinate). Examples thereof include films made of sex resins, polyolefin resins such as polypropylene (PP) and polyethylene, polyimide resins, polyarylate resins or thermoplastic resins such as mixtures thereof, and laminates thereof. Among them, polyesters, polyamides, polyethylenes, etc. A film made of polypropylene can be preferably used.
These films may be unstretched films or stretched films, and the production method thereof is not limited. Further, the thickness of the base film is not particularly limited, but usually it may be in the range of 1 to 500 μm.
Further, if the printed surface of the film is subjected to a corona discharge treatment, the adhesion to the substrate can be further improved, which is preferable. Further, silica, alumina and the like may be vapor-deposited.

The present invention will be described in more detail with reference to Examples. Hereinafter, both "part" and "%" are based on the mass standard.
The weight average molecular weight (in terms of polystyrene) was measured by GPC (gel permeation chromatography) in the present invention using the HLC8220 system manufactured by Tosoh Corporation under the following conditions.
Separation column: Uses 4 TSKgelGMH _HR -N manufactured by Tosoh Corporation. Column temperature: 40 ° C. Moving layer: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow velocity: 1.0 ml / min. Sample concentration: 1.0% by weight. Sample injection volume: 100 microliters. Detector: Differential refractometer.
The viscosity was measured at 25 ° C. with a Tokimec B-type viscometer.

[Synthesis of polyurethane resin (A)]
(Synthesis Example 1) A-1
100 parts of polyester polyol (hydroxyl value: 108 mgKOH / g) made from neopentyl glycol and sebacic acid and isophorone diisocyanate 32.3 in a four-necked flask equipped with a stirrer, thermometer, recirculation cooler and nitrogen gas introduction tube. Parts are charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 3.08% by mass, and then 71.2 parts of ethyl acetate is added thereto to make the urethane prepolymer uniform. It was made into a solution. Next, the urethane prepolymer solution was added to a mixture consisting of 8.47 parts of isophorone diamine, 0.46 parts of di-n-butylamine, 143 parts of ethyl acetate and 115 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. The polyurethane resin solution A-1 was obtained. The obtained polyurethane resin solution A-1 had a resin solid content concentration of 29.9% by mass and a weight average molecular weight of the resin solid content of 54,000.

(Synthesis Example 2) A-2
100 parts of polyester polyol (hydroxyl value: 122 mgKOH / g) made from neopentyl glycol, sebacic acid and dimer acid in a four-necked flask equipped with a stirrer, a thermometer, a recirculation cooler and a nitrogen gas introduction tube, and isophorone diisocyanate. 41.4 parts were charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 4.55% by mass, and then 76.2 parts of ethyl acetate was added to the urethane prepolymer. A uniform solution of the polymer was used. Next, the urethane prepolymer solution was added to a mixture consisting of 13.26 parts of isophorone diamine, 0.46 parts of di-n-butylamine, 159 parts of ethyl acetate and 127 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. The polyurethane resin solution A-2 was obtained. The obtained polyurethane resin solution A-2 had a resin solid content concentration of 30.1% by mass and a weight average molecular weight of the resin solid content of 32,000.

(Synthesis Example 3) A-3
100 parts of a polyester polyol made from 3-methyl-1,5-pentanediol and dimer acid (hydroxyl value: 122 mgKOH / g) in a four-necked flask equipped with a stirrer, a thermometer, a recirculation cooler and a nitrogen gas introduction tube. ) And 26.3 parts of hexamethylene diisocyanate are charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 3.07% by mass, and then 68 parts of ethyl acetate is added thereto. A uniform solution of urethane prepolymer was prepared. Next, the urethane prepolymer solution was added to a mixture consisting of 8.09 parts of isophorone diamine, 0.38 parts of di-n-butylamine, 136 parts of ethyl acetate and 110 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. A polyurethane resin solution A-3 was obtained. The obtained polyurethane resin solution A-3 had a resin solid content concentration of 30.1% by mass and a weight average molecular weight of the resin solid content of 48,000.

(Synthesis Example 4) A-4
100 parts of polyester polyol made from 3-methyl-1,5-pentanediol and sebacic acid (hydroxyl value: 108 mgKOH / g) in a four-necked flask equipped with a stirrer, thermometer, recirculation cooler and nitrogen gas introduction tube. ) And 32.3 parts of isophorone diisocyanate are charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 3.08% by mass, and then 71.2 parts of ethyl acetate is added thereto. In addition, a uniform solution of urethane prepolymer was prepared. Next, the urethane prepolymer solution was added to a mixture consisting of 8.47 parts of isophorone diamine, 0.46 parts of di-n-butylamine, 143 parts of ethyl acetate and 115 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. A polyurethane resin solution A-4 was obtained. The obtained polyurethane resin solution A-4 had a resin solid content concentration of 29.9% by mass and a weight average molecular weight of the resin solid content of 54,000.

(Synthesis Example 5) A-5
90 parts of polyester polyol (hydroxyl value: 20 mgKOH / g) made from neopentyl glycol, ethylene glycol which is a biomass raw material, and sebacic acid in a four-necked flask equipped with a stirrer, a thermometer, a recirculation cooler and a nitrogen gas introduction tube. ), 10 parts of polyethylene glycol (hydroxyl value: 56 mgKOH / g) and 14.2 parts of isophorone diisocyanate are charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to obtain a urethane prepolymer having an isocyanate group content of 3.08% by mass. After production, 61.5 parts of ethyl acetate was added thereto to prepare a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 7.09 parts of isophorondiamine, 0.92 parts of di-n-butylamine, 124 parts of ethyl acetate and 100 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. The polyurethane resin solution A-5 was obtained. The obtained polyurethane resin solution A-5 had a resin solid content concentration of 30.0% by mass and a weight average molecular weight of the resin solid content of 60,000.

(Synthesis Example 6) A-6
70 parts of polyester polyol made from neopentyl glycol, ethylene glycol which is a biomass raw material, sebacic acid and dimer acid in a four-necked flask equipped with a stirrer, a thermometer, a recirculation cooler and a nitrogen gas introduction tube (hydroxyl value: 128 mgKOH / g), 30 parts of polytetramethylene glycol (hydroxyl value: 278 mgKOH / g) and 42.5 parts of isophorone diisocyanate were charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to have an isocyanate group content of 2.15% by mass. After producing the urethane prepolymer of the above, 76.8 parts of ethyl acetate was added thereto to prepare a uniform solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 6.9 parts of isophorone diamine, 0.33 parts of di-n-butylamine, 150 parts of ethyl acetate and 122 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. A-6 polyurethane resin solution was obtained. The obtained polyurethane resin solution A-6 had a resin solid content concentration of 30.2% by mass and a weight average molecular weight of the resin solid content of 95,000.

(Synthetic Comparative Example 1) H-1
80 parts of polyester polyol (hydroxyl value: 57 mgKOH / g) made from neopentyl glycol and adipic acid, neopentyl glycol and adipine in a four-necked flask equipped with a stirrer, thermometer, recirculation cooler and nitrogen gas introduction tube. 20 parts of polyester polyol (hydroxyl value: 110 mgKOH / g) made from acid and 22.5 parts of isophorone diisocyanate are charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to make urethane having an isocyanate group content of 2.84% by mass. After producing the prepolymer, 66 parts of ethyl acetate was added thereto to prepare a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 7.25 parts of isophorone diamine, 0.27 parts of di-n-butylamine, 131 parts of ethyl acetate and 106 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. The polyurethane resin solution H-1 was obtained. The obtained polyurethane resin solution H-1 had a resin solid content concentration of 30.1% by mass and a weight average molecular weight of the resin solid content of 30,000.

(Synthetic Comparative Example 2) H-2
97 parts of polyester polyol (hydroxyl value: 140 mgKOH / g) made from ethylene glycol and adipic acid, which are biomass raw materials, and polyethylene glycol in a four-necked flask equipped with a stirrer, thermometer, recirculation cooler and nitrogen gas introduction tube. After charging 3 parts (hydroxyl value: 160 mgKOH / g) and 39.7 parts of isophorone diisocyanate and reacting them under a nitrogen stream at 90 ° C. for 10 hours to produce a urethane prepolymer having an isocyanate group content of 3.23% by mass. 75.2 parts of ethyl acetate was added thereto to prepare a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 9.71 parts of isophorone diamine, 0.11 part of di-n-butylamine, 152 parts of ethyl acetate and 122 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. The polyurethane resin solution H-2 was obtained. The obtained polyurethane resin solution H-2 had a resin solid content concentration of 30.0% by mass and a weight average molecular weight of the resin solid content of 25,000.

(Preparation of nitrocellulose solution N)
Industrial vitrified cotton H1 / 2 (nitrocellulose, solid content 30%, viscosity 9.0 to 14.9% at a solution concentration of 25.0% by JIS K-6703, manufactured by Taihei Chemicals Limited) in 37.5 parts , 62.5 parts of a mixed solution of isopropyl alcohol / ethyl acetate / normal propyl acetate / methyl cyclohexane (ratio of 25/25/13/10 by weight) was added and sufficiently mixed to prepare a nitrocellulose solution N.

(Preparation of rosin resin solution R)
50 parts of rosin resin (trade name: NEOCITE F-896, manufactured by Gangnam Kasei Co., Ltd.) was dissolved in 50 parts of isopropyl alcohol to obtain a rosin resin solution having a solid content of 50%.

[Examples 1 to 6, Comparative Examples 1 and 2: Ink adjustment method]
Mixtures of the synthesized polyurethane resin solutions Pu1 to Pu8 mixed at the blending ratios shown in Table 1 are kneaded using a mighty mill (manufactured by Inoue Seisakusho Co., Ltd.), and Examples 1 to 6 and Comparative Examples 1 and 2 are used. The indigo inks described in the above were prepared, and the following evaluations were carried out for each of them.

[Gloss]
The glossiness was measured using a gloss meter Micro-Tri-Gloss (measurement angle 60 °) manufactured by BYK in accordance with JIS Z8741: 1997.
(Evaluation criteria)
5: Glossiness is 45 or more (extremely good)
4: Glossiness is 35 or more and less than 45 (good)
3: Glossiness is 25 or more and less than 35 (usable)
2: Glossiness is 15 or more and less than 25 (defective)
1: Glossiness is less than 15 (extremely poor)

[Base adhesiveness]
The indigo ink shown in Table 1 is applied to a biaxially stretched polypropylene film (FOR thickness 20 μm manufactured by Futamura Chemical Co., Ltd.) having a corona discharge treatment on one side with a bar coater # 10, and left for 24 hours to prepare a printed matter. did.
Next, after attaching cellophane tape (manufactured by Nichiban Co., Ltd.) to this printed surface, the tape was quickly peeled off and the state of the printed surface was visually evaluated. Evaluation 4 or higher is the practical range.
(Evaluation criteria)
5: The print film does not peel off from the film at all.
4: As the area ratio of the printed film, less than 20% is peeled off from the film.
3: The area ratio of the printing film is 20% or more and less than 50% is the film.
Peel off from.
2: As the area ratio of the printing film, 50% or more and less than 80% is the film.
Peel off from.
1: As the area ratio of the printed surface, 80% or more is peeled off from the film.

[Blocking resistance]
The indigo ink shown in Table 1 is diluted with a mixed organic solvent consisting of ethyl acetate / normal propyl acetate / cyclohexane in the same ratio as that used for ink production, and diluted with Zahn Cup No. 3 manufactured by Rigo Co., Ltd. for 16 seconds. did. Using an MD type gravure printing machine (manufactured by Fuji Machinery Co., Ltd.) equipped with a laser gravure plate having a plate depth of 25 μm, a biaxially stretched polypropylene film (Futamura Chemical Co., Ltd. FOR) was subjected to corona discharge treatment on one side. Printing was performed on the treated surface having a thickness of 20 μm).
Next, the obtained printed matter was cut into a size of 4 cm × 4 cm, and the ink-coated surface and the untreated surface of the same film cut to the same size were overlapped with each other and 10 kg / cm with a vise. After tightening with the load of ^c and leaving it in an atmosphere of 40 ° C. and 80% humidity for 24 hours, the printed surface and the plastic film were peeled off by hand, and the blocking resistance was evaluated from the degree of ink peeling.
(Evaluation criteria)
5: There is no peeling of the printed film, and no peeling resistance is felt.
4: There is no peeling of the printed film, but no peeling resistance is felt.
3: The print film peels off a little, and peeling resistance is felt.
2: The print film is peeled off, and the peeling resistance is strongly felt.
1: The print film is almost peeled off, and the peeling resistance is strongly felt.

[PVC blocking resistance]
A load of 0.5 kg / cm ² was applied by superimposing the printed surface and the city's soft vinyl chloride sheet (manufactured by Doit) cut to the same size as each printed matter used in the blocking resistance evaluation. After being left for 24 hours in an atmosphere of 50 ° C. and 80% humidity, the printed surface and the polyvinyl chloride sheet were peeled off, and the vinyl chloride blocking resistance was evaluated from the degree of ink peeling.
(Evaluation criteria)
5: The printed film did not peel off at all.
4: The area where the printed film is peeled off from the film is 20% or more and less than 50%.
3: The area where the printed film is peeled off from the film is 50% or more and less than 75%.
2: The area where the printed film is peeled off from the film is 75% or more and less than 90%.
1: The area where the print film is peeled off from the film is 90% or more.

[Alcohol resistance]
The printed surface of each printed matter was rubbed 100 times under a load of 200 g with a cloth impregnated with ethanol using a Gakushin type friction resistance tester, and the alcohol suitability was evaluated from the change in the printed surface.
Evaluation 4 or higher is the practical range.
(Evaluation criteria)
5: No change on the printed surface or the cover cloth.
4: There is no change on the printed surface, but the applied cloth is colored.
3: Streaks are observed on the printed surface.
2: Thick and streaky scratches are observed on the printed surface.
1: Surface scratches are observed on the printed surface.

〔Heat-resistant〕
The indigo ink shown in Table 1 was applied to a biaxially stretched polypropylene film (FOR thickness 20 μm manufactured by Futamura Chemical Co., Ltd.) having a corona discharge treatment on one side with a bar coater # 10, and left for 24 hours to prepare a printed matter. did.
Next, using a heat seal tester equipped with a hot plate having a heat gradient of 80 to 200 ° C. on this printed surface, the printed surface and the aluminum foil, and the printed surface and the printed surface were pressed at a pressure of 2.0 kg / cm ² . Pressed for 1 second. The heat resistance was evaluated from the lowest temperature at which the ink on the printing surface transferred to the aluminum foil.
(Evaluation criteria)
5: 180 ° C or higher.
4: Those with a temperature of 160 ° C or higher and lower than 180 ° C.
3: Those with a temperature of 140 ° C or higher and lower than 160 ° C.
2: Those with a temperature of 120 ° C or higher and lower than 140 ° C.
1: Less than 120 ° C.

〔Oil resistance〕
The printed surface of each printed matter is rubbed 100 times under a load of 200 g with a cloth soaked with edible salad oil: butter at a ratio of 1: 1 using a Gakushin type friction resistance tester, and the oil resistance is evaluated from the change in the printed surface. did. Evaluation 4 or higher is the practical range.
(Evaluation criteria)
5: No change on the printed surface or the cover cloth.
4: There is no change on the printed surface, but the applied cloth is colored.
3: Streaks are observed on the printed surface.
2: Thick and streaky scratches are observed on the printed surface.
1: Surface scratches are observed on the printed surface.

[Printability test: Cassoulet test]
Isopropyl alcohol: normal propyl alcohol: ethyl acetate: normal propyl acetate: cyclohexane = (mass ratio 6 parts: 5 parts: 20 parts: 15 parts: 15 parts: the same ratio as when the indigo ink shown in Table 1 was used for ink preparation: It was diluted with a mixed organic solvent consisting of 10 parts) and diluted with Zahn Cup No. 3 manufactured by Rigo Co., Ltd. for 16 seconds. Using an MD type gravure printing machine (manufactured by Fuji Machinery Co., Ltd.) equipped with a laser gravure plate having a plate depth of 25 μm, a biaxially stretched polypropylene film (Futamura Chemical Co., Ltd. FOR) was subjected to corona discharge treatment on one side. Printing was performed on the treated surface having a thickness of 20 μm).
In the blur test, the ratio of the blur area in the highlight printed portion (halftone dot area less than 10%) and the degree of stain on the non-printed portion were visually evaluated when the printing speed was 200 m / min at a circumference of 600 mmφ of the gravure plate. .. Evaluation 4 or higher is the practical range.
(Evaluation criteria)
5: There is no blurring and there is no stain on the non-printed part.
4: Some blurring is seen, or some stains are seen on the non-printed part.
3: A little blurring is seen, and a little stain is seen on the non-printed part.
2: Blurring is seen, and stains are seen on the non-printed part.
1: A lot of blurring is seen, and a lot of stains are also seen in the non-printed part.

Table 1 shows the composition of each indigo ink and the evaluation results.

表中の略語を記す。
・可塑剤 ＡＴＢＣ：アセチルクエン酸トリブチル（トリブチル＝２－アセトキシ－１，２，３－プロパントリカルボキシラート 旭化成ファインケム（株）社製
・可塑剤 Ｓｉｂｅｒｃｉｚｅｒ Ｃ６：Ｎ－エチルｏ／ｐ－トルエンスルホンアミド、Ｍｅｒｃｋ社製

Write the abbreviations in the table.
-Plasticizer ATBC: Tributyl acetylcitrate (tributyl = 2-acetoxy-1,2,3-propanetricarboxylate, manufactured by Asahi Kasei Finechem Co., Ltd.-Plasticizer Sibercizer C6: N-ethylo / p-toluenesulfonamide, Made by Merck

From the above results, it has excellent heat resistance, blocking resistance against vinyl chloride, excellent halftone dot reproducibility without blurring of highlight points that hit small halftone dots even in high-speed printing, glossy stamp surface, and non-printing without patterns. It is possible to provide a liquid ink composition having printability such that printing stains on the portion are less likely to occur, and a printed matter obtained by printing the liquid ink composition.

Claims (7)

A liquid ink composition containing a polyurethane resin (A) using a polyester polyol as a reaction raw material, a nitrified cotton (B) , and an organic solvent (D) , wherein the polyester polyol has 7 or more carbon atoms and is carboxyl. Using polycarboxylic acid having two or more groups as a raw material
A liquid ink composition, wherein the organic solvent (D) contains an alcohol (I) having a specific evaporation rate of 100 or less when the evaporation rate of butyl acetate is 100 .
The liquid ink composition according to claim 1, further comprising a colorant (C) .
The liquid ink composition according to claim 1 or 2, further comprising a chelate compound (E) and a plasticizer (F).
The liquid ink composition according to any one of claims 1 to 3, wherein the polycarboxylic acid is sebacic acid and / or dimer acid.
The liquid ink composition according to any one of claims 1 to 4, further comprising 0.1 to 3.0% by mass of the fatty acid amide (G) in the total amount of the composition.
The liquid ink composition according to any one of claims 1 to 5, wherein the organic solvent (D) does not contain an organic solvent having an aromatic group.
A printed matter obtained by printing the liquid ink composition according to any one of claims 1 to 6 .