WO2018212011A1 - Liquid ink composition, printed matter, and laminate stack - Google Patents

Abstract

The present invention addresses the problem of providing a liquid ink composition which facilitates recovery of volatile solvents in the ink composition and which has both excellent ink transferability and laminate strength. The present invention provides a liquid ink composition comprising a polyurethane resin (A) and an organic solvent (B), characterized in that the polyurethane resin (A) includes, as reactive materials, an alkanolamine, a polyester polyol, and/or a polyether polyol, has a weight average molecular weight in a range of 30000 to 70000, a urea bond concentration of 0.8 mmol/g or less, and a hydroxyl value of 11.0 mgKOH/g or less.

Description

Liquid ink composition, printed matter and laminate laminate

The present invention relates to a liquid ink composition for gravure inks and flexographic inks for soft packaging laminates. In particular, the present invention relates to a liquid ink composition that facilitates recovery of a volatile solvent in the ink composition and has excellent ink transfer properties and laminate strength.

In recent years, the stratospheric ozone surrounding the global environment has decreased, contrary to this, air pollution problems associated with nitrogen oxides, which are the cause of the increase in tropospheric ozone, forest damage due to acid rain that photochemical ozone is implicated, etc. While VOC is a general term for volatile organic compounds, the countermeasures are focused on, and it is related to air pollution, global warming, and many other environmental problems. Various efforts are also made from this aspect.
Also in the gravure and flexographic printing industry, it is desired to take measures against VOC generation sources from the printing site by adopting low-VOC materials such as highly concentrated ink and water-based ink, and sealing the printing unit. Furthermore, there is an increasing demand for recovering the solvent in used or residual ink and using it for recycling.

Thus, a solvent recovery and reuse type printing ink composition is disclosed in which 95% or more of the volatile components contain two organic solvent components (see, for example, Patent Document 1).
Also disclosed is an organic solvent-based printing ink composition in which an ester solvent containing ethyl acetate as a main component and an alcohol solvent containing n-propyl alcohol as a main component are used in a specific mass ratio range (for example, Patent Documents 2 and 3). Furthermore, a solvent recovery reusable printing ink composition comprising two or more solvents selected from hydrocarbon solvents, ketone solvents, ester solvents, alcohol solvents and glycol solvents is disclosed (for example, (See Patent Document 4). However, these are simplified and simplified solvent compositions to facilitate solvent recovery, and the basic properties such as ink transferability and laminate strength required for printing ink during printing are never enough. It can not be said.

JP 2008-019427 A JP 2008-266370 A JP 2008-265032 A WO2007 / 145214

An object of the present invention is to provide a liquid ink composition having both excellent ink transferability and laminate strength while facilitating recovery of a volatile solvent in the ink composition.

The present invention has been found to contain a liquid ink composition containing a polyurethane resin (A) having a specific physical property value using a specific reaction raw material and an organic solvent (B), and is effective in solving the problem. It was.

That is, the present invention is a liquid ink composition containing a polyurethane resin (A) and an organic solvent (B), wherein the polyurethane resin (A) comprises an alkanolamine, a polyester polyol and / or a polyether polyol as a reaction raw material. A liquid ink composition having a weight average molecular weight in the range of 30,000 to 70,000, a urea bond concentration of 0.8 mmol / g or less, and a hydroxyl value of 11.0 mgKOH / g or less About.

Furthermore, the present invention relates to a liquid ink composition in which the alkanolamine is an alkanolamine having two or more hydroxyl groups.

Furthermore, the present invention relates to a liquid ink composition in which the polyester polyol has a number average molecular weight of 3000 to 7000.

Furthermore, this invention relates to the liquid ink composition containing the vinyl chloride vinyl acetate copolymer resin (C) which further has a hydroxyl group.

Further, in the present invention, the vinyl chloride vinyl acetate copolymer resin (C) having a hydroxyl group has a hydroxyl value of 50 to 200 mgKOH / g, and the content ratio of the vinyl chloride component in the copolymer resin is 80 to The present invention relates to a liquid ink composition that is 95% by mass.

Furthermore, this invention relates to the liquid ink composition whose amine value of the said polyurethane resin (A) is 6.5 mgKOH / g or less.

Furthermore, the present invention provides the organic solvent (B) wherein the ester solvent (b-1) is 90% by mass or more of the total amount of the organic solvent (B) and the alcohol solvent (b-2) is the organic solvent (b-2). B) 0.1% by mass or more of the total amount, and the ester solvent (b-1) is any one or more selected from the group consisting of ethyl acetate, n-propyl acetate, butyl acetate, propylene glycol monomethyl ether acetate And the alcohol-based solvent (b-2) is one or more selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-butanol. .

Furthermore, this invention relates to the printed matter formed by printing this liquid ink composition.

Furthermore, the present invention relates to a laminate laminate having a printed layer formed by printing the liquid ink composition.

According to the present invention, it is possible to provide a liquid ink composition that can easily recover the volatile solvent in the ink composition and has both excellent ink transferability and laminate strength.

The present invention will be described in detail. “Ink” used in the following description means “printing ink”. In the present invention, “liquid ink” is a low-grade ink used for a printing method in which ink is once attached to a plate and then transferred to a paper, such as a gravure printing method using a gravure plate or a flexographic printing method using a flexo plate. This refers to ink having a viscosity (approximately 1000 mPa · s or less), and representative examples include gravure ink or flexographic ink.
Further, “part” means “part by mass”.

The liquid ink composition of the present invention is a liquid ink composition containing a polyurethane resin (A) and an organic solvent (B), wherein the polyurethane resin (A) is an alkanolamine, a polyester polyol and / or a polyether polyol. And a weight average molecular weight in the range of 30000 to 70000, a urea bond concentration of 0.8 mmol / g or less, and a hydroxyl value of 11.0 mgKOH / g or less. Is.

In the polyurethane resin (A) used in the liquid ink composition of the present invention, it is essential to use alkanolamine and polyester polyol and / or polyether polyol as reaction raw materials.
The number average molecular weight of the polyester polyol is preferably 3000 to 7000.

When the number average molecular weight of the polyester polyol is less than 3000, the film of the polyurethane resin (A) tends to be hard and the adhesion to the polyester film tends to be lowered. When the number average molecular weight is larger than 7000, the polyurethane resin film tends to be brittle, and the blocking resistance of the ink film tends to be lowered. When the polyester polyol is less than 1 part by mass with respect to 100 parts by mass of the polyurethane resin (A), the solubility of the polyurethane resin (A) in ketones, esters, and alcohol-based solvents decreases, and thus a particularly high-performance barrier. The adhesion on the film tends to decrease. Further, the re-solubility of the ink film in the solvent is lowered, and the tone reproducibility of the printed matter tends to be lowered. On the other hand, if it exceeds 50 parts by mass, the ink film tends to be excessively soft and the anti-blocking tendency tends to be poor.

In addition, the number average molecular weight of the said polyester polyol shows the value measured on condition of the following by 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.
"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 “TSKgel G2000” (7.8 mm ID × 30 cm) × 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 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

As said polyester polyol, what is obtained by a well-known esterification reaction with the compound and polybasic acid which have 2 or more of hydroxyl groups can be used, for example.
The compound having two or more hydroxyl groups is used as a chain extender. For example, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6 -Glycols such as hexanediol, diethylene glycol, triethylene 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, 1,4-butanediol, 2-butyl-2-ethyl-1,3-propanediol, 1, 2-propanediol, 2-methyl-1,3- Lopandiol, neopentyl glycol, 2-isopropyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3- Glycols having a branched structure such as hexanediol, 2-ethyl-1,6-hexanediol, 3,5-heptanediol, 2-methyl-1,8-octanediol; trimethylolpropane, trimethylolethane, pentaerythritol, Aliphatic polyols such as sucrose, methylene glycol, glycerin, sorbitol; bisphenol A, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenylsulfone, hydrogenated bisphenol A, hydroquinone Good The number average molecular weight of such families polyol compounds can be used in the range of 50-400. These chain extenders may be used alone or in combination of two or more.
Examples of the polybasic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, phthalate Acids, anhydrides of these acids, and the like can be used. These polybasic acids may be used alone or in combination of two or more.

The polyether polyol preferably has a number average molecular weight of 100 to 4000. Although details will be described later, examples of the polyether polyol include polyether polyols of polymers or copolymers such as ethylene oxide, propylene oxide, and tetrahydrofuran. Specifically, known general-purpose materials such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol may be used, and polyethylene glycol is preferable. By containing the polyester polyol and / or polyether polyol in the above range, the adhesion particularly on the base film is greatly improved, and as a result, the blocking resistance and the laminate strength are improved.

Similarly, when the number average molecular weight of the polyether polyol is less than 100, the film of the polyurethane resin (A) tends to be hard, and the adhesion to the polyester film tends to be lowered. When the number average molecular weight is greater than 4000, the polyurethane resin film tends to be brittle, and the blocking resistance of the ink film tends to be lowered. When the polyester polyol is less than 1 part by mass with respect to 100 parts by mass of the polyurethane resin (A), the solubility of the polyurethane resin (A) in ketones, esters, and alcohol-based solvents decreases, and thus a particularly high-performance barrier. The adhesion on the film tends to decrease. Further, the re-solubility of the ink film in the solvent is lowered, and the tone reproducibility of the printed matter tends to be lowered. On the other hand, if it exceeds 50 parts by mass, the ink film tends to be excessively soft and the anti-blocking tendency tends to be poor. In addition, the number average molecular weight of polyether polyol was measured on the same conditions by the gel permeation chromatography (GPC) method similarly to the said polyester polyol.

Examples of the polyether polyol include polymer polyols such as methylene oxide, ethylene oxide, and tetrahydrofuran, or copolymer polyether polyols.

Further, it is preferable to use a polyester polyol and / or a polyether polyol in a proportion of 1 to 50% by mass with respect to the total amount of the polyurethane resin (A).

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 that are generally used in the production of polyurethane resins. It is done. For example, 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4′-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3- Phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, cyclohexane-1 , 4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, Melyl diisocyanate, isophorone diisocyanate (3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate; 5-isocyanato-1- (isocyanomethyl) -1,3,3-trimethylcyclohexane;), dicyclohexylmethane-4 , 4'-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, 4,4-diphenylmethane diisocyanate, tolylene diisocyanate, bis-chloromethyl-diphenylmethane Diisocyanate, which is a diisocyanate, 2,6-diisocyanate-benzyl chloride, or dimer acid with carboxyl groups converted to isocyanate groups Aneto and the like. These diisocyanate compounds can be used alone or in admixture of two or more.

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, dicyclohexylmethane-4,4′-diamine. 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 hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine It can be also used. These chain extenders can be used alone or in admixture of two or more.

An alkanolamine is essential as a terminal blocking agent for the purpose of stopping the reaction used for the polyurethane resin (A) in the liquid ink composition of the present invention. Examples of the alkanolamine include monoethanolamine, diethanolamine, and dipropanolamine. Furthermore, 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 supplementary reaction terminator. These end blockers can be used alone or in admixture of two or more.
Furthermore, if an alkanolamine having two or more hydroxyl groups is used, the adhesiveness and laminate strength of the ink composition can be further improved. By having two or more hydroxyl groups, compared with the case of one hydroxyl group, when the printed material printed with the liquid ink composition of the present invention is dry-laminated with a laminating adhesive, it reacts with the curing agent of the laminating adhesive Since the number of points increases, the laminate strength is improved. Examples of the alkanolamine having two or more hydroxyl groups include diethanolamine and dipropanolamine.

The polyurethane resin (A) in the liquid ink composition of the present invention is obtained by, for example, reacting polyethylene glycol and a combination polyol with a diisocyanate compound in an excess ratio of an isocyanate group to obtain a prepolymer of a terminal isocyanate group. Polymer is used in an appropriate solvent, that is, an ester solvent such as ethyl acetate, propyl acetate or butyl acetate, which is usually used as a solvent for gravure ink; a ketone solvent such as acetone, methyl ethyl ketone or methyl isobutyl ketone; methanol, ethanol In chain solvents such as alcohol solvents such as isopropyl alcohol and n-butanol; hydrocarbon solvents such as toluene, xylene, methylcyclohexane and ethylcyclohexane; Is prepared by a two-stage method in which a reaction is carried out with a terminal blocking agent, or a one-stage method in which polyethylene glycol and a combination polyol, diisocyanate compound, chain extender and / or terminal blocking agent are reacted at once in a suitable solvent. The Among these methods, it is preferable to use a two-stage method in order to obtain a uniform polyurethane resin. When the polyurethane resin is produced by a two-stage method, the reaction is performed so that the total (equivalent ratio) of amino groups of the chain extender and / or end-capping agent is 1 / 0.9 to 1.3. It is preferable. When the equivalent ratio of isocyanate group to amino group is less than 1 / 1.3, the chain extender and / or the end-capping agent remain unreacted, the polyurethane resin turns yellow, or the odor after printing May occur.
In recent years, it is more preferable not to use an aromatic solvent or a ketone solvent such as toluene or xylene from the viewpoint of the working environment.

The weight average molecular weight of the polyurethane resin (A) thus obtained is in the range of 30,000 to 70,000, more preferably in the range of 35,000 to 65,000. When the weight average molecular weight of the polyurethane resin is less than 30,000, the blocking resistance of the ink composition obtained, the strength of the printed film and the oil resistance tend to be low, and when it exceeds 70,000, There is a tendency for the viscosity of the resulting ink composition to increase and the gloss of the printed film to decrease.
In addition, the measurement of the weight average molecular weight (polystyrene conversion) by GPC (gel permeation chromatography) in this invention was performed on condition of the following using the Tosoh Corporation HLC8220 system.
Separation column: 4 TSKgelGMH _HR- N manufactured by Tosoh Corporation are used. Column temperature: 40 ° C. Moving layer: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow rate: 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.

It is essential that the urea bond concentration of the polyurethane resin (A) used in the liquid ink composition of the present invention is 0.8 mmol / g or less and the hydroxyl value is 11.0 mgKOH / g or less. When the urea bond concentration exceeds 0.8 mmol / g, the hardness of the composition increases more than necessary and the flexibility of the laminate tends to decrease, and the fluidity also deteriorates. There is a tendency that the highlight transferability of the printed matter also decreases due to a change in the viscosity of the ink. When the hydroxyl value exceeds 11.0 mgKOH / g, the water resistance tends to decrease and the laminate strength after retort tends to decrease. From the viewpoint of maintaining adhesiveness and laminate strength, the urea bond concentration is more preferably in the range of 0.3 to 0.8 mmol / g, and the hydroxyl value is more preferably in the range of 0.5 to 10.0 mgKOH / g. preferable.
The relationship of urea bond concentration can be calculated by the following equation (1).

Urea binding concentration = [(X1 / eq1 + X2 / eq2 + ... Xi / eqi)-{(W1 x OH1 + W2 x OH2 + ... + Wi x OHi) / 56100}] x 1000 / S Equation (1)

When a plurality of isocyanate compounds and polyols are used, they are calculated as isocyanate compound 1, isocyanate compound 2 to isocyanate compound i, and polyol 1, polyol 2 to polyol i, respectively.

In the formula (1), each is as follows.

X1: Mass of isocyanate compound 1
eq1: Isocyanate equivalent of isocyanate compound 1
X2: Mass of isocyanate compound 2
eq2: Isocyanate equivalent of isocyanate compound 2
Xi: Mass of isocyanate compound i
eqi: Isocyanate equivalent of isocyanate compound i
W1: Mass of polyol 1
OH1: hydroxyl value of polyol 1
W2: Mass of polyol 2
OH2: hydroxyl value of polyol 2
Wi: Mass of polyol i
OHi: hydroxyl value of polyol i
S: Mass of urethane resin solids

Furthermore, the amine value of the polyurethane resin (A) used in the liquid ink composition of the present invention is preferably 6.5 mgKOH / g or less. When the amine value exceeds 6.5 mgKOH / g, the blocking resistance tends to be inferior. The range of 1.0 to 5.0 mgKOH / g is more preferable, and 1.0 to 3.5 mgKOH / g is more preferable from the viewpoint of maintaining the plate fogging property, adhesiveness and extrusion laminate strength while maintaining good blocking resistance. The range of g.

The content of the polyurethane resin (A) used in the liquid ink composition of the present invention in the ink is 5% by mass or more with respect to the total mass of the ink from the viewpoint of sufficient adhesion of the ink to the printing medium. From the viewpoint of the ink viscosity and the work efficiency during ink production and printing, it is preferably 50% by mass or less, and more preferably in the range of 10 to 40% by mass.

As the organic solvent (B) used in the liquid ink composition of the present invention, various organic solvents can be used, for example, aromatic organic solvents such as toluene and xylene, ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone. Solvent, ester solvent such as ethyl acetate, n-propyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, alcohol solvent such as n-propanol, inopropanol, n-butanol, propylene glycol monomethyl ether, etc. Can be used alone or in a mixture of two or more.

The organic solvent (B) is prepared from the ester solvent (b-1) in the total amount of the organic solvent (B) from the viewpoint of easy adjustment of drying property at a suitable evaporation rate during printing and solubility of the polyurethane resin. 90% by mass or more, and 0.1% by mass or more of the alcoholic solvent (b-2) based on the total amount of the organic solvent (B), and the ester solvent (b-1) is ethyl acetate, n-propyl acetate, One or more selected from the group consisting of butyl acetate and propylene glycol monomethyl ether acetate, and the alcohol solvent (b-2) is selected from ethanol, 1-propanol, 2-propanol, 1-butanol and 2-butanol. It is preferable that any one or more selected from the group consisting of the following groups, and if limited to the above-described configuration containing no ketones, the waste solvent is less colored and easy to purify and more efficiently. Can be collected.
If the ester solvent (b-1) / alcohol solvent (b-2) are used together under the above conditions, the water has a low azeotropic point, so that water mixed during printing can be easily removed. Further, it can be recovered as a mixed solvent at a high yield, and can be easily reused as a diluting solvent.
For example, 2-isopropyl isopropyl alcohol (IPA) and 1-propanol normal propyl alcohol (NPA) are separated by isopropyl acetate (IPAC) and normal propyl acetate (NPAC) in the purification step after recovery, respectively. Therefore, when the ester solvent is normal propyl acetate (NPAC), the purification process can be further simplified by selecting normal propyl alcohol (NPA) as the alcohol solvent (b-2).

Furthermore, in the liquid ink composition of the present invention, a vinyl chloride vinyl acetate copolymer resin (C) may be added.
The vinyl chloride vinyl acetate copolymer resin (C) preferably has a hydroxyl group, the hydroxyl value is 50 to 200 mg KOH / g, and the content ratio of the vinyl chloride component in the copolymer resin is 80 to 95 mass. % Is preferable. When the vinyl chloride / vinyl acetate copolymer resin (C) is present, the cohesive strength of the ink film increases and the blocking resistance tends to be good. Furthermore, by using a blocking agent in combination, the improvement in blocking resistance is further improved.

The vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group used in the liquid ink composition of the present invention can be obtained by two kinds of methods. One is obtained by copolymerizing vinyl chloride monomer, vinyl acetate monomer and vinyl alcohol in appropriate proportions. The other is obtained by copolymerizing vinyl chloride and vinyl acetate and then partially saponifying vinyl acetate. In the vinyl chloride vinyl acetate copolymer resin having a hydroxyl group, the properties of the resin film and the resin dissolution behavior are determined by the monomer ratio of vinyl chloride, vinyl acetate and vinyl alcohol. That is, vinyl chloride imparts toughness and hardness of the resin coating, vinyl acetate imparts adhesion and flexibility, and vinyl alcohol imparts good solubility in polar solvents.

When liquid ink is used as a laminating ink for soft packaging, it needs to satisfy all of these properties: adhesiveness, anti-blocking, laminate strength, boil retort suitability, printability, vinyl chloride vinyl acetate copolymer with hydroxyl groups The resin has a proper monomer ratio. That is, the vinyl chloride content is preferably 80 to 95% by mass relative to the vinyl chloride vinyl acetate copolymer resin having a hydroxyl group. If it is less than 80% by mass, the toughness of the resin film is inferior and the blocking resistance is lowered. If it exceeds 95% by mass, the resin coating becomes too hard and the adhesiveness is lowered. The hydroxyl value obtained from vinyl alcohol is preferably 50 to 200 mgKOH / g. If it is less than 50 mgKOH / g, the solubility in a polar solvent is poor and the printability is poor. When it exceeds 200 mgKOH / g, the water resistance is lowered and the suitability for boil and retort becomes poor.

Examples of the resin used together as necessary in the liquid ink composition of the present invention include resins other than the polyurethane resin and vinyl chloride-vinyl acetate copolymer resin, such as chlorinated polypropylene resin, ethylene-vinyl acetate copolymer Combined 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, chlorinated rubber, butyral, petroleum resin, etc. Can be mentioned. The combined resins can be used alone or in admixture of two or more. The content of the combined resin is preferably 1 to 50% by mass, more preferably 2 to 40% by mass, based on the total mass of the ink.

Examples of the color pigment used in the liquid ink composition of the present invention include organic and inorganic pigments and dyes used in general inks, paints, and recording agents. Organic pigments include azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethine azo, dictopyrrolopyrrole, isoindoline, etc. Pigments. Indigo ink is copper phthalocyanine, and transparent yellow ink is C.I. I. Pigment No. Yellow83 is preferably used.

Examples of the inorganic pigment include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, bengara, aluminum, mica (mica), and the like. Further, a luster pigment (Metashine; Nippon Sheet Glass Co., Ltd.) having glass or block flake as a base material and coated with metal or metal oxide can be used. From the viewpoints of cost and coloring power, it is preferable to use titanium oxide for white ink, carbon black for black ink, aluminum for silver ink, and mica for pearl ink. Aluminum is in the form of powder or paste, but is preferably used in the form of paste from the viewpoint of handling and safety, and whether to use leafing or non-leafing is appropriately selected from the viewpoint of brightness and concentration.
The colorant is preferably contained in an amount sufficient to ensure the density and coloring power of the ink, that is, 1 to 50% by mass relative to the total mass of the ink. Moreover, a coloring agent can be used individually or in combination of 2 or more types.

In the present invention, a combination resin, extender pigment, pigment dispersant, leveling agent, antifoaming agent, wax, plasticizer, infrared absorber, ultraviolet absorber, fragrance, flame retardant and the like can also be included as necessary. .

In order to stably disperse the colored pigment in the organic solvent, the resin alone can be dispersed, but a dispersant can also be used in combination in order to disperse the pigment stably. As the dispersant, anionic, nonionic, cationic, amphoteric surfactants can be used. For example, a comb-structure polymer compound obtained by adding polyester to polyethyleneimine, or an alkylamine derivative of an α-olefin maleic acid polymer may be used. Specific examples include Solsperz series (ZENECA), Ajisper series (Ajinomoto), and homogenol series (Kao). Further, BYK series (Bic Chemie), EFKA series (EFKA), and the like can be used as appropriate. The dispersant is preferably contained in the ink in an amount of 0.05% by mass or more based on the total mass of the ink from the viewpoint of the storage stability of the ink and 5% by mass or less from the viewpoint of the suitability for lamination. The range is from 1 to 2% by mass.

The liquid ink composition of the present invention can be produced by dissolving and / or dispersing a resin, a color pigment 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 other compounds as necessary. it can.

The particle size distribution of the pigment in the pigment dispersion is adjusted by appropriately adjusting the size of the grinding media of the disperser, the filling rate of the grinding media, the dispersion treatment time, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, and the like. be able to. As a 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.
In the case where bubbles or unexpectedly large particles are included in the ink, it is preferably removed by filtration or the like in order to reduce the quality of the printed matter. A conventionally well-known filter can be used.

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

As the hue of the liquid ink composition of the present invention, there are five basic colors of yellow, red, indigo, black, and white, depending on the type of pigment used, and red (orange) as a color outside the process gamut. There are three colors: grass (green) and purple. Further, transparent yellow, peony, vermilion, brown, gold, silver, pearl, almost transparent medium for adjusting color density (including extender pigments if necessary), etc. are prepared as base colors. The boil retort ink is appropriately selected in consideration of pigment migration and heat resistance. The base ink of each hue is diluted with a diluting solvent to a viscosity and density suitable for gravure printing or flexographic printing, and is supplied alone or mixed to each printing unit.

The liquid ink composition of the present invention can be obtained as a printed matter and a coating by applying the printing and application to the various film and sheet-like substrates using the printing method described above, and drying and fixing by drying in an oven. Can do. Film and sheet base materials include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate, polycarbonate and polylactic acid, polystyrene resins such as polystyrene, AS resin and ABS resin, nylon, polyamide and poly Examples include vinyl chloride, polyvinylidene chloride, cellophane, paper, aluminum, and composite materials thereof.

The base material may be subjected to vapor deposition coating treatment and / or polyvinyl alcohol coating treatment on the surface of metal oxide or the like, and may further be subjected to surface treatment such as corona treatment.

Furthermore, the usual extrusion lamination (extrusion laminating) method in which molten polyethylene resin is laminated on the printed surface of the printed material through various anchor coating agents such as imine, isocyanate, polybutadiene, and titanium, and urethane on the printed surface The printing ink of the present invention was used by a known laminating process such as a dry laminating method in which an adhesive such as a system is applied and a plastic film is laminated, or a direct laminating method in which a molten polypropylene is directly pressed and laminated on a printing surface. Laminate laminate is obtained

The liquid ink composition of the present invention can easily separate and recover the ester / alcohol component when recovering the mixed solvent and generated VOC gas generated in the printing and drying processes as a liquid.

The present invention will be described more specifically with reference to examples. Hereinafter, both “parts” and “%” are based on mass.
The hydroxyl value is the amount of hydroxyl group in 1 g of resin calculated by back titrating the remaining acid with alkali when the hydroxyl group in the polyurethane resin is acetylated with an excess of acetyl reagent. It is shown by the number of mg, and conforms to JISK0070.
The amine value indicates the number of mg of potassium hydroxide (KOH) equivalent to the equivalent amount of hydrochloric acid required to neutralize the amino group contained in 1 g of polyurethane resin. As the measurement method, 30 mL of neutral ethanol was added to and dissolved in a sample accurately weighed P grams, and the resulting solution was titrated with a 0.2 mol / L ethanolic hydrochloric acid solution (titer f). . The time when the color of the solution changed from green to yellow was regarded as the end point, and the amine value was determined by the following (formula 2) using the titration amount (HmL) at this time.
In addition, the said sample refers to the polyurethane resin solution obtained by each synthesis example, and calculates it by solid content mass conversion 30%.
Amine value = (H × f × 0.2 × 56.108) /P/0.3 [mg KOH / g] Formula (2)

(Synthesis Example 1: Preparation of polyurethane resin solution X1)
A polyester polyol 228.71 having a number average molecular weight of 3700 obtained from adipic acid and neopentyl glycol was added to a 1 liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth reflux condenser, and a nitrogen gas introduction tube. Parts and 12.03 parts of polyethylene glycol (PEG # 1000) having a number average molecular weight of 1000 were charged, and the temperature was raised to 50 ° C. while stirring and flowing nitrogen gas. Subsequently, 42.98 parts of isophorone diisocyanate was added, and the mixture was reacted at 90 ° C. until NCO%, which is a residual ratio of isocyanate groups, reached 3.40%. After cooling, 152.77 parts of n-propyl acetate was added to obtain a urethane prepolymer solution (A1) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. 19.44 parts, 2.48 parts of diethanolamine, 414.00 parts of n-propyl acetate, 143.00 parts of n-propyl alcohol, and 436.50 parts of urethane prepolymer solution (A1) are added and reacted at 45 ° C. for 4 hours. A polyurethane resin solution having a solid content of 30%, a weight average molecular weight of 31,600, an amine value of 3.2 (mgKOH / g), a urea bond concentration of 0.8 mmol / g, and a hydroxyl value of 7.4 (mgKOH / g) X1) was obtained.

(Synthesis Example 2: Preparation of polyurethane resin solution X2)
A polyester polyol 725.00 having a number average molecular weight of 3700 obtained from adipic acid and neopentyl glycol was added to a 1 liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. And 38.15 parts of polyethylene glycol (PEG # 1000) having a number average molecular weight of 1000 were charged, and the temperature was raised to 50 ° C. while stirring and flowing nitrogen gas. Subsequently, 124.01 parts of isophorone diisocyanate was added, and the reaction was continued at 90 ° C. until NCO%, which is the residual ratio of isocyanate groups, reached 2.83%. After cooling, 477.70 parts of n-propyl acetate was added to obtain a urethane prepolymer solution (A2) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. 52.77 parts, diethanolamine 4.85 parts, n-propyl acetate 1286 parts, n-propyl alcohol 441 parts were added, urethane prepolymer solution (A2) 13364.86 parts were added, and reacted at 45 ° C. for 4 hours. Polyurethane resin solution (X2) having a solid content of 30%, a weight average molecular weight of 42,500, an amine value of 3.2 (mgKOH / g), a urea bond concentration of 0.7 mmol / g, and a hydroxyl value of 4.7 (mgKOH / g) Got.

(Synthesis Example 3: Preparation of polyurethane resin solution X3)
A polyester polyol 228.71 having a number average molecular weight of 3700 obtained from adipic acid and neopentyl glycol was added to a 1 liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth reflux condenser, and a nitrogen gas introduction tube. Parts and 12.03 parts of polyethylene glycol (PEG # 1000) having a number average molecular weight of 1000 were charged, and the temperature was raised to 50 ° C. while stirring and flowing nitrogen gas. Subsequently, 35.32 parts of isophorone diisocyanate was added, and the mixture was reacted at 90 ° C. until NCO%, which is a residual ratio of isocyanate groups, reached 2.43%. After cooling, 148.65 parts of n-propyl acetate was added to obtain a urethane prepolymer solution (A3) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. 14.23 parts, 1.50 parts of diethanolamine, 396.00 parts of n-propyl acetate, 136.00 parts of n-propyl alcohol, and 424.71 parts of urethane prepolymer solution (A3) are added and reacted at 45 ° C. for 4 hours. A polyurethane resin solution having a solid content of 30%, a weight average molecular weight of 47,000, an amine value of 3.2 (mgKOH / g), a urea bond concentration of 0.6 mmol / g, and a hydroxyl value of 5.5 (mgKOH / g) X3) was obtained.

(Synthesis Example 4: Preparation of polyurethane resin solution X4)
Number average molecular weight obtained from adipic acid and 3-methyl-1,5-pentanediol in a 1 liter four-necked flask equipped with a stirrer, thermometer, Dimroth type reflux condenser, and nitrogen gas inlet tube 264.2 parts of 5100 polyester polyol was charged, nitrogen gas was passed, and the temperature was raised to 50 ° C. with stirring. Subsequently, 28.01 parts of isophorone diisocyanate was added, and the mixture was reacted at 90 ° C. until NCO%, which is a residual ratio of isocyanate groups, reached 1.99%. After cooling, 157.34 parts of n-propyl acetate was added to obtain a urethane prepolymer solution (A4) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. 10.96 parts, 2.36 parts of diethanolamine, 413.00 parts of n-propyl acetate, 143.00 parts of n-propyl alcohol, and 449.55 parts of urethane prepolymer solution (A4) are added and reacted at 45 ° C. for 4 hours. A polyurethane resin solution having a solid content of 30%, a weight average molecular weight of 41,100, an amine value of 1.5 (mgKHO / g), a urea bond concentration of 0.5 mmol / g, and a hydroxyl value of 8.2 (mgKOH / g) X4) was obtained.

(Synthesis Example 5: Preparation of polyurethane resin solution X5)
Number average molecular weight obtained from adipic acid and 3-methyl-1,5-pentanediol in a 1 liter four-necked flask equipped with a stirrer, thermometer, Dimroth type reflux condenser, and nitrogen gas inlet tube 264.2 parts of 5100 polyester polyol was charged, nitrogen gas was passed, and the temperature was raised to 50 ° C. with stirring. Subsequently, 28.01 parts of isophorone diisocyanate was added, and the mixture was reacted at 90 ° C. until NCO%, which is the residual ratio of isocyanate groups, reached 1.98%. After cooling, 157.34 parts of n-propyl acetate was added to obtain a urethane prepolymer solution (A5) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. 10.27 parts, 3.16 parts of diethanolamine, 414.00 parts of n-propyl acetate, 143.00 parts of n-propyl alcohol, and 449.55 parts of urethane prepolymer solution (A5) were added and reacted at 45 ° C. for 4 hours. A polyurethane resin solution having a solid content of 30%, a weight average molecular weight of 62,800, an amine value of 1.5 (mgKOH / g), a urea bond concentration of 0.5 mmol / g, and a hydroxyl value of 11.0 (mgKOH / g) X5) was obtained.

(Synthesis Example 6: Preparation of polyurethane resin solution X6)
Number average molecular weight obtained from adipic acid and 3-methyl-1,5-pentanediol in a 1 liter four-necked flask equipped with a stirrer, thermometer, Dimroth type reflux condenser, and nitrogen gas inlet tube 404.70 parts of 5100 polyester polyol was charged, nitrogen gas was passed, and the temperature was raised to 50 ° C. while stirring. Subsequently, 37.37 parts of isophorone diisocyanate was added, and the mixture was reacted at 90 ° C. until NCO%, which is a residual ratio of isocyanate groups, reached 1.62%. After cooling, 238.04 parts of n-propyl acetate was added to obtain a urethane prepolymer solution (A6) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. 14.15 parts, diethanolamine 2.88 parts, n-propyl acetate 620.00 parts, n-propyl alcohol 215.00 parts, urethane prepolymer solution (A6) 680.11 parts are added and reacted at 45 ° C. for 4 hours. A polyurethane resin solution having a solid content of 30%, a weight average molecular weight of 31,600, an amine value of 2.0 (mgKOH / g), a urea bond concentration of 0.3 mmol / g, and a hydroxyl value of 6.7 (mgKOH / g) X6) was obtained.

(Synthesis Example 7: Preparation of polyurethane resin solution X7)
Number average molecular weight obtained from adipic acid and 3-methyl-1,5-pentanediol in a 1 liter four-necked flask equipped with a stirrer, thermometer, Dimroth type reflux condenser, and nitrogen gas inlet tube 264.20 parts of 5100 polyester polyol was charged, nitrogen gas was passed, and the temperature was raised to 50 ° C. while stirring. Subsequently, 28.01 parts of isophorone diisocyanate was added, and the reaction was continued at 90 ° C. until the NCO%, which is the residual ratio of isocyanate groups, reached 1.99%. After cooling, 157.34 parts of n-propyl acetate was added to obtain a urethane prepolymer solution (B2) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. 10.96 parts, 1.37 parts of monoethanolamine, 411.00 parts of n-propyl acetate, 142.00 parts of n-propyl alcohol, and 449.55 parts of urethane prepolymer solution (B2) are added at 45 ° C. for 4 hours. A polyurethane resin having a solid content of 30%, a weight average molecular weight of 48,000, an amine value of 1.5 (mgKOH / g), a urea bond concentration of 0.5 mmol / g, and a hydroxyl value of 4.1 (mgKOH / g) upon reaction. A solution (X7) was obtained.

(Synthesis Comparative Example 1: Preparation of polyurethane resin solution Y1)
A polyester polyol 228.71 having a number average molecular weight of 3700 obtained from adipic acid and neopentyl glycol was added to a 1 liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth reflux condenser, and a nitrogen gas introduction tube. Parts and 12.03 parts of polyethylene glycol (PEG # 1000) having a number average molecular weight of 1000 were charged, and the temperature was raised to 50 ° C. while stirring and flowing nitrogen gas. Subsequently, 46.81 parts of isophorone diisocyanate was added, and the reaction was continued at 90 ° C. until the NCO%, which is the residual ratio of isocyanate groups, reached 3.60%. After cooling, 154.84 parts of n-propyl acetate was added to obtain a urethane prepolymer solution (B1) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. 20.89 parts, 2.51 parts of diethanolamine, 426.000 parts of n-propyl acetate, 145.00 parts of n-propyl alcohol, and 442.39 parts of urethane prepolymer solution (B1) were added and reacted at 45 ° C. for 4 hours. A polyurethane resin solution having a solid content of 30%, a weight average molecular weight of 31,800, an amine value of 3.2 (mgKOH / g), a urea bond concentration of 0.9 mmol / g, and a hydroxyl value of 7.4 (mgKOH / g) Y1) was obtained.

(Synthesis Comparative Example 2: Preparation of polyurethane resin solution Y2)
In a 1 liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth reflux condenser, and a nitrogen gas introduction tube, 107.41 parts of a polyester polyol having a number average molecular weight of 2000 obtained from adipic acid and propylene glycol And 107.41 parts of polypropylene glycol (PPG # 1000) having a number average molecular weight of 1000 were charged, and the temperature was raised to 50 ° C. while stirring and flowing nitrogen gas. Subsequently, 56.11 parts of tolylene diisocyanate was added, and the reaction was continued at 90 ° C. until the NCO%, which is the residual ratio of isocyanate groups, reached 4.80%. After cooling, 82.5 parts of ethyl acetate was added to obtain a urethane prepolymer solution (B3) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. 27.67 parts, 1.41 parts of diethanolamine, 327.47 parts of ethyl acetate, 290.00 parts of isopropyl alcohol, 416.82 parts of urethane prepolymer solution (B3) were added and reacted at 45 ° C. for 4 hours to obtain a solid content. A polyurethane resin solution (Y2) having 30%, a weight average molecular weight of 32,400, an amine value of 4.5 (mgKOH / g), a urea bond concentration of 1.1 mmol / g, and a hydroxyl value of 5.0 (mgKOH / g) is obtained. It was.

(Synthesis Comparative Example 3: Preparation of polyurethane resin solution Y3)
A polyester polyol 228.71 having a number average molecular weight of 3700 obtained from adipic acid and neopentyl glycol was added to a 1 liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth reflux condenser, and a nitrogen gas introduction tube. Parts and 12.03 parts of polyethylene glycol (PEG # 1000) having a number average molecular weight of 1000 were charged, and the temperature was raised to 50 ° C. while stirring and flowing nitrogen gas. Subsequently, 41.46 parts of isophorone diisocyanate was added, and the mixture was reacted at 90 ° C. until NCO%, which is a residual ratio of isocyanate groups, reached 2.50%. After cooling, 151.96 parts of n-propyl acetate was added to obtain a urethane prepolymer solution (B4) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. 18.57 parts, 3.99 parts of diethanolamine, 417.00 parts of n-propyl acetate, 142.00 parts of n-propyl alcohol, and 434.17 parts of urethane prepolymer solution (B4) are added and reacted at 45 ° C. for 4 hours. 30% solid content, weight average molecular weight 32,500, amine value 3.2 (mgKOH / g), urea bond concentration 0.8 mmol / g, hydroxyl value 12.0 (mgKOH / g) polyurethane resin solution (Y3 )

(Synthesis Comparative Example 4: Preparation of polyurethane resin solution Y4)
A polyester polyol 228.71 having a number average molecular weight of 3700 obtained from adipic acid and neopentyl glycol was added to a 1 liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth reflux condenser, and a nitrogen gas introduction tube. Parts and 12.03 parts of polyethylene glycol (PEG # 1000) having a number average molecular weight of 1000 were charged, and the temperature was raised to 50 ° C. while stirring and flowing nitrogen gas. Subsequently, 25.51 parts of isophorone diisocyanate was added, and the mixture was reacted at 90 ° C. until NCO%, which is a residual ratio of isocyanate groups, reached 1.20%. After cooling, 143.37 parts of n-propyl acetate was added to obtain a urethane prepolymer solution (B4) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. 6.35 parts, 1.07 parts of diethanolamine, 367.00 parts of n-propyl acetate, 128.00 parts of n-propyl alcohol and 409.62 parts of urethane prepolymer solution (B4) are added and reacted at 45 ° C. for 4 hours. 30% solid content, weight average molecular weight 71,000, amine value 0.7 (mgKOH / g), urea bond concentration 0.3 mmol / g, hydroxyl value 3.6 (mgKOH / g) polyurethane resin solution (Y4 )

(Synthesis Comparative Example 5: Preparation of polyurethane resin solution Y5)
A polyester polyol 228.71 having a number average molecular weight of 3700 obtained from adipic acid and neopentyl glycol was added to a 1 liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth reflux condenser, and a nitrogen gas introduction tube. Parts and 12.03 parts of polyethylene glycol (PEG # 1000) having a number average molecular weight of 1000 were charged, and the temperature was raised to 50 ° C. while stirring and flowing nitrogen gas. Subsequently, 25.51 parts of isophorone diisocyanate was added, and the mixture was reacted at 90 ° C. until NCO%, which is a residual ratio of isocyanate groups, reached 1.20%. After cooling, 143.37 parts of n-propyl acetate was added to obtain a urethane prepolymer solution (B5) having an isocyanate group at the terminal.
Subsequently, 1-amino-3-aminomethyl-3,5,5-trimethylcyclohexane was added to a 1-liter four-necked flask equipped with a stirrer, a thermometer, a Dimroth type reflux condenser, and a nitrogen gas introduction tube. Add 5.35 parts, diethanolamine 0.30 parts, n-propyl acetate 364.00 parts, n-propyl alcohol 127.00 parts, urethane prepolymer solution (B4) 409.62 parts, and react at 45 ° C. for 4 hours. 30% solid content, weight average molecular weight 25,000, amine value 3.7 (mgKOH / g), urea bond concentration 0.3 mmol / g, hydroxyl value 12.9 (mgKOH / g) polyurethane resin solution (Y5 )

(Preparation of vinyl chloride vinyl acetate copolymer resin solution)
Vinyl chloride vinyl acetate copolymer resin having a hydroxyl group used in combination with a polyurethane resin (resin monomer composition is mass% vinyl chloride / vinyl acetate / vinyl alcohol = 92/3/5, hydroxyl value (mgKOH) = 64) is acetic acid. A 15% solution was made with n-propyl, and this was made into a vinyl acetate resin solution (V1).

Example 1
Fastogen Blue FA5375 10.00 parts, vinyl chloride vinyl acetate copolymer resin 30.00 parts n-propyl acetate 15% solution (V1), n-propyl acetate / n-propyl alcohol mixed solvent (weight ratio 90/10) 10 0.000 part was stirred and mixed, and after kneading with a paint conditioner, 30.00 parts of polyurethane resin composition X1 and 20.00 parts of a mixed solvent of n-propyl acetate / n-propyl alcohol (weight ratio 90/10) were stirred. By mixing, an indigo ink composition was obtained. This was diluted with n-propyl acetate, and adjusted at 25 ° C. to 16 seconds with Zaan Cup # 3 (manufactured by Hogosha).
Hereinafter, in accordance with the formulation of Table 3, Examples 2 to 7 were performed in the same procedure as in Example 1, Examples 8 to 14 were performed according to the formulation of Table 4, and Comparative Examples 1, 3 to 5 were performed according to the formulation of Table 5. The ink was adjusted. Examples 8 to 14 and Comparative Example 2 were diluted with ethyl acetate / isopropyl alcohol = 50/50 (mass ratio), further diluted with ethyl acetate, and Zahn Cup # 3 at 25 ° C. as in Example 1. The time was adjusted to 16 seconds (manufactured by Fengsha). Tables 3 to 5 show the ester / alcohol solvent ratio (mass ratio) in the final indigo ink.

The obtained liquid indigo ink is printed using a gravure printing machine (manufactured by DIC Engineering Co., Ltd.) equipped with a laser gravure plate having a plate depth of 35 μm, highlight transferability of printed matter, measurement of laminate strength, solvent recovery Efficiency was evaluated. The evaluation results are shown in Tables 3-5. Evaluation was performed by the following method.

(1) Highlight transferability Printed on a biaxially stretched polypropylene (OPP) film P2161 (thickness: 20 μm) manufactured by Toyobo Co., Ltd. Immediately after the start of printing, each highlight transferability after idling 2 hours and idling 4 hours Was visually evaluated. The evaluation criteria were as follows.
(Evaluation criteria)
5: Slight blur is not seen in the gradation part 4: Slight blur is seen in the gradation part 3: Smudge is seen in the gradation part 2: Smudge is noticeable in the gradation part 1: Scratch is seen in the gradation part Is often seen

(2) Measurement of laminate strength Biaxial stretching of the obtained liquid indigo ink with corona treatment on one side using a gravure printing machine (manufactured by DIC Engineering Co., Ltd.) equipped with a laser gravure plate having a plate depth of 25 μm. Printing was performed on the treated surface of a polyester film (E-5100 PET film having a thickness of 12 μm manufactured by Toyobo Co., Ltd.).
Aluminum foil and unstretched polypropylene film were printed on the printed biaxially stretched polyester film using urethane-based dry laminate adhesive Dick Dry LX-703VL / KR-90 (made by DIC) using a dry laminating machine (made by DIC Engineering). (Hereinafter, R-CPP: ZK-75 50 μm manufactured by Toray Synthetic Film Co., Ltd.) was laminated and aged at 40 ° C. for 3 days to obtain a laminate.
The obtained laminate was formed into a bag having a size of 120 mm × 120 mm and filled with 70 g of pseudo food containing vinegar, salad oil, and meat sauce in a weight ratio of 1: 1: 1. The prepared pouch was sterilized by steam retort at 135 ° C for 30 minutes, then the contents were taken out and the pouch was washed with water. went.
The produced laminate was made of PET substrate (F) / printing ink layer (I) / adhesive layer (Ad1) / aluminum foil (AL) / adhesive (Ad2) / R-CPP film from the PET film side of the substrate. In order.
A biaxially stretched polyester film (PET film: E-5100, 12 μm thick, manufactured by Toyobo Co., Ltd.) was used.
The larger the value, the higher the strength.
The abbreviations of the evaluation results in Tables 3 to 5 are as follows.

F Cut: An abbreviation for FILM CUT, which represents that the film is broken before the laminate peels during measurement. The laminate strength is higher as it exceeds the film strength, indicating superiority.
I / AL: It peeled with the measured value shown by the adhesive layer (Ad1) between printing ink layer (I) and aluminum foil (AL).
F / I: Peeling was performed between the PET substrate (F) / printing ink layer (I) with the measured values shown.

(3) Solvent recovery efficiency In advance, a solvent recovery tester (manufactured by Kureha Engineering) was connected by a duct from the exhaust port of the dryer of the gravure printing machine (manufactured by DIC Engineering). Printing was performed with a gravure plate having a plate depth of 35 μm under the same conditions as in the (1) highlight transferability test, and the pH of the solvent recovered by a recovery device after 4 hours of idling was measured. The pH was measured by adding 100 g of the recovered solvent to a separatory funnel containing 100 g of water, shaking the mixture for 2 minutes, separating the water, and measuring the pH of the water with a pH meter. The evaluation criteria were the following three stages.
(Evaluation criteria)
: PH 5 or more and less than pH 8.
(Triangle | delta): It is pH3 or more and less than pH5.
X: pH is less than 3.

From the above results, the liquid ink composition of the present invention has excellent volatile solvent recovery efficiency due to less dissolution of the dissolved component of the pigment in the solvent, and also has excellent ink transferability and laminate strength. Can be combined.

The liquid ink composition of the present invention can be widely used in industrial products such as food packaging materials, sanitary products, cosmetics, and electronic parts as gravure inks and flexographic inks suitable for solvent recovery and reuse that facilitates recovery of the solvent used. .

Claims (9)

1. A liquid ink composition containing a polyurethane resin (A) and an organic solvent (B), wherein the polyurethane resin (A) comprises an alkanolamine, a polyester polyol and / or a polyether polyol as reaction raw materials, and a weight average. The molecular weight is in the range of 30000-70000, the urea bond concentration is 0.8 mmol / g or less, and the hydroxyl value is 11.0 mgKOH / g or less.
   A liquid ink composition characterized by the above.
   
2. The liquid ink composition according to claim 1, wherein the alkanolamine is an alkanolamine having two or more hydroxyl groups.
   
3. The liquid ink composition according to claim 1, wherein the polyester polyol has a number average molecular weight of 3000 to 7000.
   
4. The liquid ink composition according to any one of claims 1 to 3, further comprising a vinyl chloride vinyl acetate copolymer resin (C) having a hydroxyl group.
   
5. The hydroxyl value of the vinyl chloride vinyl acetate copolymer resin (C) having a hydroxyl group is 50 to 200 mgKOH / g, and the content ratio of the vinyl chloride component in the copolymer resin is 80 to 95% by mass. Item 4. A liquid ink composition according to any one of Items 1 to 4.
   
6. The liquid ink composition according to any one of claims 1 to 5, wherein the amine value of the polyurethane resin (A) is 6.5 mgKOH / g or less.
   
7. In the organic solvent (B), the ester solvent (b-1) is 90% by mass or more of the total amount of the organic solvent (B), and the alcohol solvent (b-2) is 0.02% of the total amount of the organic solvent (B). Containing 1% by mass or more,
   The ester solvent (b-1) is any one or more selected from the group consisting of ethyl acetate, n-propyl acetate, butyl acetate, propylene glycol monomethyl ether acetate,
   7. The alcohol solvent (b-2) is any one or more selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol and 2-butanol. The liquid ink composition as described in one.
   
8. A printed matter obtained by printing the liquid ink composition according to any one of claims 1 to 7.
   
9. A laminate laminate having a printed layer formed by printing the liquid ink composition according to any one of claims 1 to 7.