JP7129771B2 - liquid ink composition - Google Patents

Description

TECHNICAL FIELD The present invention relates to a liquid ink composition that can be used as a laminate gravure ink for flexible packaging or a flexographic ink.

Gravure inks and flexographic inks are widely used for the purpose of imparting aesthetic properties and functionality to printed materials. When a gravure or flexographic printed material is used as a packaging material, particularly as a food packaging material, it is generally subjected to lamination. In this case, various printing materials and lamination processes are used depending on the type of contents and purpose of use.

Conventionally, printing inks containing polyurethane resin as a binder have been widely used for such laminates because of their excellent adhesion to various printed materials, lamination strength of various laminates, and suitability for boiling and retorting.

For example, Patent Literature 1 discloses a printing ink composition for lamination comprising, as a main binder resin, an organic solvent-soluble polyurethane polyurea resin obtained by reacting a polymeric diol, an organic diisocyanate, and a diamine as a chain extender. It is After that, various studies were made to improve the physical properties of the laminate. In Patent Document 2, in a polyurethane resin obtained from a polymeric diol and an organic diisocyanate, adhesion is improved by using a polyester polyol obtained from 3-methyl-1,5-pentanediol and a dibasic acid as a polymeric diol compound. , hydrolysis resistance, and improved resolubility.
Patent Document 3 discloses a polyurethane resin obtained by reacting a polyester polyol obtained by polycondensing 2-butyl-2-ethyl-1,3-propanediol with a polycarboxylic acid with a polyisocyanate.
Patent Document 4 discloses a polyurethane resin obtained from a polyester diol obtained from 2,4-diethyl-1,5-pentanediol and dicarboxylic acid and an organic diisocyanate compound.
Patent Literature 5 describes a flexible packaging laminate ink composition comprising, as essential components, a polypropylene glycol-containing polyurethane resin and a vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group.
Patent Documents 6 and 7 describe a polyester-based urethane resin with a specified range of urea bond concentration as a printing ink binder for laminated cans.
Patent Documents 8 and 9 describe polyurethane resins obtained by reacting a specific diol component with an organic diisocyanate and an amine-based chain extender.

However, with the recent diversification of packaging substrates, printing inks used for decoration or surface protection are required to have a high level of performance. The current situation is that there is nothing to do.
Moreover, especially in recent years, the demand for environment-friendly products for the purpose of countermeasures against global warming and reduction of environmental load is increasing. However, in the prior art, in addition to basic printability, while improving adhesion to various substrates, laminate strength, and retort suitability, some of the raw materials of liquid ink compositions are plant-derived. It is by no means easy to satisfy the improvement of environmental responsiveness by incorporating ingredients.

JP-A-55-25453 JP-A-63-161065 JP-A-6-41264 JP-A-2000-273382 JP 2005-298618 A JP-A-11-172184 Japanese Patent Application Laid-Open No. 2002-294129 JP-A-6-80921 JP-A-11-279472

An object of the present invention is to provide a liquid ink composition having adhesion to various functional film substrates, lamination strength, retort resistance, and good printability.

The inventors of the present invention have made intensive studies to solve the above problems, and as a result, in a liquid ink composition, polyurethane resin (A) and vinyl chloride vinyl acetate copolymer resin (B) using polyester polyol as a reaction raw material In the liquid ink composition containing, the polyester polyol is found to be effective in solving the problem by using a polycarboxylic acid having 7 or more carbon atoms and two or more carboxyl groups as a raw material.

That is, the present invention provides a liquid ink composition containing a polyurethane resin (A) using a polyester polyol as a reaction raw material and a vinyl chloride-vinyl acetate copolymer resin (B), wherein the polyester polyol has 7 carbon atoms. As described above, the present invention relates to a liquid ink composition characterized by using a polycarboxylic acid having two or more carboxyl groups as a raw material.

Moreover, the present invention further relates to a liquid ink composition containing less than 10% by mass of water (C) based on the total amount of the composition.

The present invention also relates to a liquid ink composition containing 1 to 40% by mass of a polyether polyol as a component of the polyurethane resin (A) with respect to the total amount of the polyurethane resin (A).

The present invention also relates to a liquid ink composition wherein the polyether polyol has a number average molecular weight of 100-3500.

Moreover, the present invention further relates to a liquid ink composition containing a colorant (D) and an organic solvent (E).

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

Further, in the present invention, the vinyl chloride-vinyl acetate copolymer resin (B) has a hydroxyl group, the hydroxyl value is 50 to 200 mg equivalent KOH, and the content of the vinyl chloride component in the copolymer resin is It relates to a liquid ink composition that is 80 to 95% by mass.

The present invention also relates to a liquid ink composition in which the organic solvent (E) does not contain an aromatic group-free organic solvent and/or a ketone solvent.

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

In addition, the present invention relates to a laminated laminate comprising said printed matter.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to obtain a liquid ink composition having adhesion to various functional film substrates, lamination strength, retort resistance, and good printability.

The present invention will be described in detail. Note that "ink" used in the following description all means "printing ink". Moreover, all "parts" indicate "parts by mass".

The present invention provides a liquid ink composition containing a polyurethane resin (A) using a polyester polyol as a reaction raw material and a vinyl chloride-vinyl acetate copolymer resin (B), wherein the polyester polyol has 7 or more carbon atoms, and The liquid ink composition is characterized by using a polycarboxylic acid having two or more carboxyl groups as a raw material.

Specifically, the liquid ink composition of the present invention comprises a polyurethane resin (A) and a vinyl chloride vinyl acetate copolymer resin (B) mixed with various organic solvents such as ethyl acetate, methyl ethyl ketone, toluene and IPA, and optionally water ( C), and various additives are premixed using a dispersing stirrer. Water may be added in advance to the organic solvent to obtain 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 dispersing stirrer and further stirring. In the case of an ink composition, the ink composition is obtained by adding the colorant (D) and sufficiently dispersing it.

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 optionally a monovalent active hydrogen compound.

The polyester polyol, which is the reaction raw material of the polyurethane resin (A) used in the liquid ink composition of the present invention, is essentially made of a polycarboxylic acid having 7 or more carbon atoms and two or more carboxyl groups, Obtained by reacting with a compound having two or more hydroxyl groups.
Polyester polyol can further increase the lamination strength by introducing an ester group to increase the polarity. Therefore, it is possible to combine appropriate flexibility and lamination strength.

Examples of polycarboxylic acids 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 suberic acid. , azelaic acid, sebacic acid, dimer acid and other aliphatic dicarboxylic acids, trimellitic acid and its anhydrides and other tricarboxylic acids, benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid and anhydrides of these acids, etc. can be used. These polybasic acids may be used alone or in combination of two or more. Among them, sebacic acid and dimer acid are preferable in terms of obtaining adhesion to a wide variety of film substrates and high laminate strength, and these may be used alone or in combination.

Other polyvalent carboxylic acids may be used for the polyester polyol, if necessary, and various known polyvalent carboxylic acids generally used in the production of polyester polyols may be used. The above may be used in combination. Examples include adipic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid and glutaric 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, 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, 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, Sorbitol and the like can be used. These compounds may be used alone or in combination of two or more.

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, even more preferably in the range of 900 to 6,000. .
In the present invention, the number-average and weight-average molecular weights are values measured by gel permeation chromatography (GPC) under the following conditions.

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" (7.8mm I.D. x 30cm) x 1 "TSKgel G4000" (7.8mm I.D. x 30cm) x 1 "TSKgel G3000" (7.8mm I.D. x 30cm) x 1 Book "TSKgel G2000" (7.8 mm I.D. x 30 cm) x 1 Detector: RI (differential refractometer)
Column temperature: 40°C
Eluent: Tetrahydrofuran (THF)
Flow rate: 1.0 mL/min Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was created 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

Furthermore, it is more preferable to contain polyether polyol as a constituent component of the polyurethane resin (A) in an amount of 1 to 40% by mass based on the polyurethane resin (A). As the polyether polyol, various known ether polyols generally used for producing polyurethane resins can be used, and one or more of them may be used in combination. Examples thereof include polyether polyols of polymers or copolymers such as ethylene oxide, propylene oxide and tetrahydrofuran. When the polyether polyol is 1% by mass or more based on 100% by mass of the polyurethane resin (A), the urethane resin has good solubility in ketone, ester, and alcohol solvents, and the ink film is formed in the solvent. re-dissolution in the toner is unlikely to decrease, and tone reproducibility of printed matter is unlikely to deteriorate. Moreover, if it is 40 mass % or less, blocking resistance will hardly fall.

Further, the polyether polyol preferably has a number average molecular weight of 100 to 3,500. When the polyether polyol has a number average molecular weight of 100 or more, the film of the polyurethane resin (A) does not harden and the adhesiveness to the polyester film does not easily decrease. If the number average molecular weight is 3500 or less, the tendency of the film of the polyurethane resin (A) to become brittle can be suppressed, and the blocking resistance of the ink film tends to be less likely to decrease.

Various known polyols commonly used in the production of polyurethane resins can be used as the combination polyol used as needed in the polyurethane resin (A) used in the liquid ink composition of the present invention. Or you may use 2 or more types together. 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-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4-butylenediol, diethylene glycol, triethylene glycol , dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, pentaerythritol, and other saturated or unsaturated low-molecular-weight polyols (1) these low-molecular-weight polyols (1), adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, and spelic acid , azelaic acid, sebacic acid, trimellitic acid, pyromellitic acid and other polycarboxylic acids or polyester polyols obtained by dehydration condensation or polymerization with these anhydrides (2); cyclic ester compounds such as polycaprolactone, Polyester polyols (3) obtained by ring-opening polymerization of lactones such as polyvalerolactone and poly(β-methyl-γ-valerolactone); Polycarbonate polyols obtained by reaction with diphenyl carbonate, ethylene carbonate, phosgene, etc. (4); Polybutadiene glycols (5); Glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A (6); 1 molecule Acrylic obtained by copolymerizing one or more of hydroxyethyl, hydroxypropyl acrylate, acrylic hydroxybutyl, etc., or their corresponding methacrylic acid derivatives, etc. with, for example, acrylic acid, methacrylic acid, or an ester thereof and polyol (7).

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. be done. For example, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-2,5-phenylene diisocyanate, 1 -methyl-2,6-phenylene diisocyanate, 1-methyl-3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene diisocyanate, 1-isopropyl-2,4-phenylene diisocyanate, 1,3-dimethyl-2 ,4-phenylene diisocyanate, 1,3-dimethyl-4,6-phenylene diisocyanate, 1,4-dimethyl-2,5-phenylene diisocyanate, 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 polyisocyanates ; tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di(isocyanate methyl)cyclohexane, 1,4-di(isocyanatomethyl)cyclohexane, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 3, 3'-dimethyl-4,4'-dicyclohexylmethane Aliphatic or alicyclic polyisocyanates such as diisocyanates can be used. These polyisocyanates may be used alone or in combination of two or more. Among these, it is preferable to use aliphatic polyisocyanate and/or alicyclic polyisocyanate from the point that moderate flexibility can be obtained, and isophorone diisocyanate and hexamethylene diisocyanate are used from the point that the adhesive strength can be further improved. is more preferable.

Chain extenders used in the polyurethane resin (A) in the ink composition for flexible packaging laminates of the present invention include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4, In addition to 4'-diamine, etc., 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylene Amines having a hydroxyl group in the molecule such as diamine, 2-hydroxypyropyrethylenediamine, di-2-hydroxypyropyrethylenediamine and di-2-hydroxypropylethylenediamine can also be used. These chain extenders can be used alone or in combination of two or more.
A monovalent active hydrogen compound can also be used as a terminal blocker for the purpose of terminating the reaction. Examples of such compounds include dialkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol. Furthermore, amino acids such as glycine and L-alanine can be used as a reaction terminator, especially when it is desired to introduce a carboxyl group into the polyurethane resin. These terminal blocking agents can be used alone or in combination 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 optionally a monovalent active hydrogen compound. For example, a polyester polyol or a combined polyol and a diisocyanate compound are reacted in a proportion in which the isocyanate groups are excessive to obtain a prepolymer having terminal isocyanate groups, and the obtained prepolymer is dissolved in an appropriate solvent, that is, a liquid ink solvent. 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, Hydrocarbon solvents such as xylene, methylcyclohexane, ethylcyclohexane; or a two-step method of reacting with a chain extender and (or) a 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 blocking agent are reacted together in a suitable solvent among the above. Among these methods, the two-step method is preferred for obtaining a uniform polyurethane resin (A). Further, when the polyurethane resin (A) is produced by a two-step method, the total (equivalent ratio) of the amino groups of the chain extender and (or) terminal blocker is 1/0.9 to 1.3. is preferably reacted with. If the equivalent ratio of the isocyanate group to the amino group is less than 1/1.3, the chain extender and/or the terminal blocker remain unreacted, causing yellowing of the polyurethane resin and odor after printing. 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 of the resulting ink composition and the strength and oil resistance of the printed film are difficult to decrease. The viscosity of the ink composition used does not become too high, and the glossiness of the printed film can be easily maintained. The weight average molecular weight of the polyurethane resin (A) is the 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 relative to the total amount of the composition is 4% by mass or more relative to the total amount of the composition from the viewpoint of ensuring sufficient adhesion of the ink to the substrate to be printed. From the viewpoint of appropriate ink viscosity and work efficiency during ink production and printing, the content is preferably 25% by mass or less, more preferably 6 to 15% by mass.

Furthermore, in the liquid ink composition of the present invention, in addition to the polyurethane resin (A), the hydroxyl-containing vinyl chloride-vinyl acetate copolymer resin (B) is essential, thereby further improving retort resistance.

The vinyl chloride-vinyl acetate copolymer resin (B) having a hydroxyl group has a hydroxyl value of 50 to 200 mgKOH/g and a vinyl chloride component content ratio in the copolymer resin of 80 to 95% by weight. is preferred.

The vinyl chloride-vinyl acetate copolymer resin having hydroxyl groups used in the present invention can be obtained by two 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. The vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group determines the properties of the resin film and the dissolution behavior of the resin depending on the monomer ratio of vinyl chloride, vinyl acetate and vinyl alcohol. That is, vinyl chloride imparts toughness and hardness to the resin coating, vinyl acetate imparts adhesiveness and flexibility, and vinyl alcohol imparts good solubility in polar solvents.

When the liquid ink composition of the present invention is used as a laminating ink for flexible packaging, it is necessary to satisfy all of these properties such as adhesion, blocking resistance, lamination strength, boil retort suitability, and printability. A vinyl vinyl acetate copolymer resin has an appropriate monomer ratio. That is, the amount of vinyl chloride is preferably 80 to 95 parts by mass with respect to 100 parts by mass of a vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group. If the content is 80 parts by mass or more, the toughness of the resin coating can be maintained, and blocking resistance can be secured. When the content is 95 parts by mass or less, the resin film does not become too hard and the adhesiveness is less likely to decrease. Moreover, the hydroxyl value obtained from vinyl alcohol is preferably 50 to 200 mgKOH/g. If it is 50 mgKOH/g or more, the solubility in polar solvents is good, and the printability tends to be stable. If it is 200 mgKOH/g or less, good boiling and retort suitability can be maintained without lowering the water resistance.

Water (C) may be added to the liquid ink composition of the present invention together with the organic solvent as a volatile component. By adding water (C), it is possible to control the drying property of the ink, and particularly in gravure printing, it is possible to clearly reproduce the gradation portion with a small amount of ink transfer, which is a characteristic of gravure printing. The amount of water (C) to be added is preferably in the range of 0.3 to 10% by mass based on the total amount of the ink composition from the viewpoint of good printability. When the amount of water added is 0.3% by mass or more, the reproducibility of the gradation portion tends to be good without lowering the effect of suppressing drying of the ink, and the amount of water added is 10% of the total amount of the ink composition. If it is less than mass %, it can also suppress that ink stability falls.
Moreover, by adding such water (C), it is possible to reduce the amount of organic solvent components used, which leads to environmental friendliness. Water (C) may be added in advance to the organic solvent (D) to form a water-containing organic solvent, or a specific amount may be added separately.

Examples of the coloring agent (D) used in the present invention include organic and inorganic pigments and dyes used in general inks, paints, recording agents, and the like. Examples of organic pigments include azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethineazo, ditopyrrolopyrrole, and isoindoline pigments. pigments. Copper phthalocyanine is used for indigo ink, and C.I. I. Pigment No Yellow 83 is preferably used.

Examples of inorganic pigments include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, red iron oxide, aluminum, and mica (mica). A bright pigment (Metashine; Nippon Sheet Glass Co., Ltd.) obtained by coating glass flakes or massive flakes as a base material with a metal or a metal oxide can also be used. From the viewpoint of cost and coloring power, it is preferable to use titanium oxide for white ink, carbon black for black ink, aluminum for gold and silver inks, and mica for pearl ink. Although aluminum is in the form of powder or paste, it is preferable to use it in the form of paste from the standpoint of handling and safety, and whether to use leafing or non-leafing is appropriately selected from the viewpoint of brightness and density.
The coloring agent is preferably contained in an amount sufficient to ensure the density and coloring power of the ink, that is, in a proportion of 1 to 50% by weight based on the total weight of the ink. Moreover, a coloring agent can be used individually or in combination of 2 or more types.

Next, the organic solvent (E) used in the present invention will be explained. In the ink composition for flexible packaging laminates of the present invention, for example, aromatic organic solvents, ketone-based solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, and Alcohol solvents such as ester solvents, n-propanol, inopropanol, n-butanol, and propylene glycol monomethyl ether can be mentioned, and these can be used alone or in combination of two or more. In recent years, from the viewpoint of work environment, it is desirable not to use aromatic solvents such as toluene and xylene and ketone solvents.

Examples of resins that are optionally used in the flexible packaging laminate ink composition of the present invention include resins other than the aforementioned polyurethane resins and vinyl chloride-vinyl acetate copolymer resins, such as chlorinated polypropylene resins and ethylene-acetic acid resins. 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, chlorinated rubber, butyral, petroleum resin etc. 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.

In the present invention, a combined resin, extender pigment, pigment dispersant, leveling agent, antifoaming agent, wax, plasticizer, infrared absorber, ultraviolet absorber, aromatic agent, flame retardant, etc. can also be included, 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. Anionic, nonionic, cationic, and amphoteric surfactants can be used as dispersants. 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 Solspers series (ZENECA), Ajisper series (Ajinomoto), Homogenol series (Kao), and the like. BYK series (BYK-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 relative to 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 lamination suitability, and more preferably 0%. .1 to 2% by weight.

The liquid ink composition of the present invention can be produced by dissolving and/or dispersing a resin, colorant, etc. in an organic solvent. Specifically, an ink can be produced by producing a pigment dispersion by dispersing a pigment in an organic solvent using a polyurethane resin, and blending other compounds into the obtained pigment dispersion as necessary. 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 processing time, the ejection speed of the pigment dispersion, the viscosity of the pigment dispersion, and the like. be able to. As the dispersing machine, commonly used roller mills, ball mills, pebble mills, attritors, sand mills and the like can be used.
If air bubbles or unexpected coarse particles are contained in the ink, it is preferable to remove them by filtration or the like, as they reduce the quality of printed matter. A conventionally known filter can be used.

The viscosity of the ink produced by the above method is preferably in the range of 10 mPa·s or more from the viewpoint of preventing sedimentation of the pigment and appropriately dispersing the pigment, and in the range of 1000 mPa·s or less from the viewpoint of work efficiency during ink production and printing. preferable. The above viscosity is measured at 25° C. with a B-type viscometer manufactured by Tokimec.
The viscosity of the ink can be adjusted by appropriately selecting the types and amounts of raw materials used, such as polyurethane resins, colorants, organic solvents, and the like. Also, the viscosity of the ink can be adjusted by adjusting the particle size and particle size distribution of the pigment in the ink.

Among the liquid ink compositions of the present invention, when the coloring agent (D) is used, the hue is yellow, red, indigo, black, or white as the basic process color, depending on the type of coloring agent (D) used. There are 5 colors, and 3 colors of red (orange), grass (green), and purple are available as process gamut external colors. Further, transparent yellow, peony, vermillion, brown, gold, silver, pearl, almost transparent medium for adjusting color density (including extender pigment if necessary), etc. are prepared as base colors. The ink for boiling retort is appropriately selected in consideration of the migration property and heat resistance of the pigment. 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 supplied to each printing unit singly or in combination.

Plastic films that can be used as substrates are not particularly limited, and examples include polyamide resins such as Ny6, nylon 66, and nylon 46, polyethylene phthalate (PET), polyethylene naphthalate, polytrimethylene terephthalate, and polytrimethylene naphthalate. , 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). polyolefin resins such as polyolefin resins such as polypropylene (PP) and polyethylene, films made of thermoplastic resins such as polyimide resins, polyarylate resins or mixtures thereof, and laminates thereof. A film made of polypropylene can be preferably used.
These films may be either unstretched films or stretched films, and the manufacturing method thereof is not limited. Also, the thickness of the base film is not particularly limited, but it is usually in the range of 1 to 500 μm.
In addition, if the printed surface of the film is subjected to corona discharge treatment, the adhesiveness to the substrate can be further improved, which is preferable. Also, silica, alumina, or the like may be vapor-deposited.

EXAMPLES The present invention will be described more specifically with reference to Examples. Hereinafter, "parts" and "%" are based on mass.
The measurement of the weight average molecular weight (in terms of polystyrene) by GPC (gel permeation chromatography) in the present invention was carried out under the following conditions using an HLC8220 system manufactured by Tosoh Corporation.
Separation column: Four TSKgelGMH _HR -N manufactured by Tosoh Corporation are used. Column temperature: 40°C. Moving bed: 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.
Viscosity was measured at 25° C. with a B-type viscometer manufactured by Tokimec.

[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 32.3 parts of isophorone diisocyanate were placed in a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube. 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. solution. Next, the urethane prepolymer solution was added to a mixture of 8.47 parts of isophoronediamine, 0.46 parts of di-n-butylamine, 143 parts of ethyl acetate and 115 parts of isopropyl alcohol, and the reaction was stirred at 45°C for 5 hours. to obtain a polyurethane resin solution A-1. The obtained polyurethane resin solution A-1 had a resin solid content concentration of 29.9 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 mg KOH/g) and hexamethylene diisocyanate 26.26. 3 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 3.07% by mass. and Next, the urethane prepolymer solution was added to a mixture of 8.09 parts of isophoronediamine, 0.38 parts of di-n-butylamine, 136 parts of ethyl acetate and 110 parts of isopropyl alcohol, and the reaction was stirred at 45°C for 5 hours. to obtain a polyurethane resin solution A-2. 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 48,000.

(Synthesis Example 3) A-3
100 parts of polyester polyol (hydroxyl value: 122 mg KOH/g) and isophorone diisocyanate made from neopentyl glycol, sebacic acid and dimer acid as raw materials are placed in a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube. 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. A homogenous solution of the polymer was obtained. Next, the urethane prepolymer solution was added to a mixture of 13.26 parts of isophoronediamine, 0.46 parts of di-n-butylamine, 159 parts of ethyl acetate and 127 parts of isopropyl alcohol, and the reaction was stirred at 45°C for 5 hours. Thus, a polyurethane resin solution A-3 was obtained. The obtained polyurethane resin solution A-3 had a resin solid content concentration of 30.1 mass % and a weight average molecular weight of the resin solid content of 32,000.

(Synthesis Example 4) A-4
In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, 95 parts of polyester polyol made from neopentyl glycol and sebacic acid (hydroxyl value: 35 mg KOH / g) and 5 parts of polyethylene glycol ( Hydroxyl value: 111 mg KOH/g) and 17.5 parts of isophorone diisocyanate 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 3.08% by mass. 63.2 parts of ethyl was added to obtain a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 7.55 parts of isophoronediamine, 0.72 parts of di-n-butylamine, 127 parts of ethyl acetate and 103 parts of isopropyl alcohol, and the reaction was stirred at 45°C for 5 hours. Thus, a polyurethane resin solution A-4 was obtained. The obtained polyurethane resin solution A-4 had a resin solid content concentration of 30.1% by mass and a weight average molecular weight of the resin solid content of 70,000.

(Synthesis Example 5) A-5
In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, 90 parts of a polyester polyol made from neopentyl glycol and sebacic acid (hydroxyl value: 20 mg KOH / g) and 10 parts of polyethylene glycol ( Hydroxyl value: 56 mg KOH/g) and 14.2 parts of isophorone diisocyanate 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 3.08% by mass. 61.5 parts of ethyl was added to obtain a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 7.09 parts of isophoronediamine, 0.92 parts of di-n-butylamine, 124 parts of ethyl acetate and 100 parts of isopropyl alcohol, and the reaction was stirred at 45°C for 5 hours. Thus, a 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
In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, 70 parts of a polyester polyol made from neopentyl glycol and sebacic acid (hydroxyl value: 128 mgKOH/g) and 30 parts of polytetramethylene glycol were added. (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 produce a urethane prepolymer having an isocyanate group content of 2.15% by mass. 76.8 parts of ethyl acetate was added to the solution to obtain a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 6.9 parts of isophoronediamine, 0.33 parts of di-n-butylamine, 150 parts of ethyl acetate and 122 parts of isopropyl alcohol, and the reaction was stirred at 45° C. for 5 hours. Thus, a polyurethane resin solution A-6 was obtained. The obtained polyurethane resin solution A-6 had a resin solid content concentration of 30.2 mass % and a weight average molecular weight of the resin solid content of 95,000.

(Synthesis Example 7) A-7
95 parts of polyester polyol (hydroxyl value: 122 mgKOH/g) and polyethylene glycol made from neopentyl glycol, sebacic acid and dimer acid were added to a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube. 5 parts (hydroxyl value: 278 mgKOH/g) and 37.2 parts of isophorone diisocyanate 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 3.10% by mass. 73.9 parts of ethyl acetate was added thereto to obtain a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 8.72 parts of isophoronediamine, 0.54 parts of di-n-butylamine, 148 parts of ethyl acetate and 120 parts of isopropyl alcohol, and the reaction was stirred at 45°C for 5 hours. Thus, a polyurethane resin solution A-7 was obtained. The obtained polyurethane resin solution A-7 had a resin solid content concentration of 30.1 mass % and a weight average molecular weight of the resin solid content of 25,000.

(Comparative Synthesis 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 were placed in a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube. 20 parts of polyester polyol (hydroxyl value: 110 mgKOH/g) and 22.5 parts of isophorone diisocyanate, which are made from acid, are charged and reacted at 90° C. for 10 hours under a nitrogen stream to produce urethane with an isocyanate group content of 2.84% by mass. After the prepolymer was produced, 66 parts of ethyl acetate was added thereto to obtain a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 7.25 parts of isophoronediamine, 0.27 parts of di-n-butylamine, 131 parts of ethyl acetate and 106 parts of isopropyl alcohol, and the reaction was stirred at 45°C for 5 hours. Thus, a polyurethane resin solution H-1 was obtained. The obtained polyurethane resin solution H-1 had a resin solid content concentration of 30.1 mass % and a weight average molecular weight of the resin solid content of 30,000.

(Comparative Synthesis Example 2) H-2
In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, 97 parts of polyester polyol (hydroxyl value: 140 mg KOH / g) made from neopentyl glycol and adipic acid as raw materials and 3 parts of polyethylene glycol ( Hydroxyl value: 160 mgKOH/g) and 39.7 parts of isophorone diisocyanate 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 3.23% by mass. 75.2 parts of ethyl was added to obtain a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture of 9.71 parts of isophoronediamine, 0.11 parts of di-n-butylamine, 152 parts of ethyl acetate and 122 parts of isopropyl alcohol, and the reaction was stirred at 45°C for 5 hours. Thus, a polyurethane resin solution H-2 was obtained. The obtained polyurethane resin solution H-2 had a resin solid content concentration of 30.0 mass % and a weight average molecular weight of the resin solid content of 25,000.

(Adjustment of vinyl chloride vinyl acetate copolymer resin solution)
A vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group used in combination with a polyurethane resin (vinyl chloride/vinyl acetate/vinyl alcohol = 92/3/5, hydroxyl value (mgKOH) = 64 in terms of weight percent of the resin monomer) is mixed with acetic acid. A 15% solution was made with ethyl, and this was used as a vinyl chloride resin solution (B-1).

[Example 1]
30 parts of the resulting polyurethane resin solution A-1, 30 parts of vinyl chloride-vinyl acetate copolymer resin solution A-1 having a hydroxyl group (15% solution), 10 parts of phthalocyanine blue pigment (FASTGEN Blue LA5380 manufactured by DIC Corporation) ), 27 parts of ethyl acetate, and 3 parts of water were kneaded to prepare a blue printing ink.

[Evaluation item 1: Adhesion to various films]
The viscosity of the resulting liquid indigo ink was adjusted to 16 seconds (25°C) with a Zahn cup #3 (manufactured by Rigosha) with ethyl acetate, and the results shown in Tables 1 and 2 were obtained using a gravure proofreader equipped with a gravure plate with a plate depth of 35 µm. Various barrier films (W, X, Y, Z) shown, biaxially oriented polyester film U with corona treatment on one side (hereinafter referred to as PET film, E-5100 manufactured by Toyobo Co., Ltd., thickness 12 μm), biaxially oriented polypropylene When a print made with film V (hereinafter referred to as OPP film, P2161 manufactured by Toyobo Co., Ltd., thickness 20 μm) was left for one day, and cellophane tape (12 mm width manufactured by Nichiban) was attached to the printed surface and quickly peeled off. The state of the appearance of the printed film was visually evaluated in the following five stages.

5: The printed film was not peeled off at all.
4: 70% or more to less than 90% of the printed film remained on the film.
3: 50% or more to less than 70% of the printed film remained on the film.
2: 30% or more to less than 50% of the printed film remained on the film.
1: Only less than 30% of the print film remained.

Barrier film to be evaluated W: Alumina deposited transparent PET film IB-PET-PUB (thickness: 12 μm) manufactured by Dai Nippon Printing Co., Ltd.
X: Silica deposition transparent PET film manufactured by Mitsubishi Plastics Co., Ltd. Tech Barrier TX-R (thickness: 12 μm)
Y: Oike Industry Co., Ltd. Silica deposition transparent PET film MOS-TEB (thickness: 12 μm)
Z: Aluminum oxide deposited transparent PET film GL-ARH (thickness: 12 μm) manufactured by Toppan Printing Co., Ltd.

[Evaluation item 2: Lamination strength PET/CPP, OPP/CPP]
An ether-based dry lamination adhesive Dick Dry LX-401A/SP-60 (manufactured by DIC) was applied to the printed matter so that the coating amount was ^2.5 g/m Office) to laminate an unstretched polypropylene film (hereinafter referred to as CPP: P1128 20 μm manufactured by Toyobo Co., Ltd.) and aged at 40 ° C. for 3 days to obtain a laminate, then cut into a width of 15 mm and pulled at a speed of 300 mm / min. A 90 degree peel test was performed at
The larger the numerical value, the higher the lamination strength.

[Evaluation item 3: printability, blurring resistance, biaxially oriented polyester film (PET film)]
The viscosity of the obtained liquid indigo ink was diluted with a mixed organic solvent of ethyl acetate/isopropyl alcohol=50/50, and diluted with a Zahn cup #3 (manufactured by Rigosha Co., Ltd.) at 25° C. to a viscosity of 16 seconds. The resulting liquid indigo ink was applied to a biaxially oriented polyester film U (Toyobo Co., Ltd. Printing was performed on the treated surface of E-5100 (manufactured by Co., Ltd., thickness 12 μm). Then, the degree of transfer of the ink to the printed portion of the printed matter (the blurring degree) was visually evaluated in the following three stages. The blurring test was evaluated at a printing speed of 300 m/min with a circumference of the gravure plate of 600 mmφ.

A: No blurring occurred.
Δ: Slight blurring occurs.
x: Fragmentation occurs frequently.

[Evaluation item 4: retort resistance]
A urethane-based dry lamination adhesive Dick Dry LX-500/KW-75 (manufactured by DIC) was applied to the PET film printed matter so that the coating amount was 3.5 g/m ² , dried, and then dried using a dry lamination machine (( A two-layer laminate 1 was obtained by laminating an aluminum foil (hereinafter, AL: aluminum foil C manufactured by Toyo Aluminum Industry Co., Ltd., 15 μm) by Musashino Machine Design Office. Next, the adhesive was applied to the AL of the laminate 1 in the same manner, a non-stretched polypropylene film (hereinafter, R-CPP: ZK-93KM 50 μm manufactured by Toray Synthetic Film Co., Ltd.) was laminated, and aged at 40 ° C. for 5 days, A three-layer composite laminate 2 was obtained. Thereafter, the obtained laminate 2 was formed into a pouch having a size of 120 mm×120 mm, and 70 g of simulated food mixed with water/salad oil=1:1 (weight ratio) was filled and sealed. The prepared pouch was subjected to steam retort sterilization at 135° C. for 30 minutes, and then the degree of peeling was evaluated according to the following evaluation criteria.

○: No peeling.
Δ: There is small blister-like peeling.
x: Peeling is observed on the entire surface regardless of size.

[Examples 1 to 9, Comparative Examples 1 to 4]
Inks were prepared in the same procedure as in Example 1 using the compositions shown in Examples 1 to 9 and Comparative Examples 1 to 3 shown in Tables 1 and 2.
Each evaluation result is also written together.

The liquid ink composition of the present invention has adhesion to various functional film substrates, lamination strength, retort resistance, and good printability.

INDUSTRIAL APPLICABILITY The liquid ink composition of the present invention can be widely used for industrial products such as food packaging materials, sanitary products, cosmetics, electronic parts, etc., where demand for various film structures is expected.

Claims (9)

A liquid ink composition containing a polyurethane resin (A) using a polyester polyol as a reaction raw material, a vinyl chloride-vinyl acetate copolymer resin (B) , water (C), and an organic solvent (E) ,
Containing 0.3% by mass or more and less than 10% by mass of the water (C) of the total amount of the composition,
The polyester polyol uses a polycarboxylic acid having 7 or more carbon atoms and two or more carboxyl groups as a raw material,
Furthermore, as a constituent component of the polyurethane resin (A), 1 to 40% by mass of polyether polyol is contained with respect to the total amount of the polyurethane resin (A) (however, the polyurethane resin (A) does not contain a castor oil polyol-derived structure. )
A liquid ink composition characterized by: 2. A liquid ink composition according to claim 1, wherein said polyether polyol is a polymer or copolymer selected from ethylene oxide, propylene oxide and tetrahydrofuran. 3. The liquid ink composition according to claim 1, wherein the polyether polyol has a number average molecular weight of 100-3500. 4. The liquid ink composition according to any one of Claims 1 to 3 , further comprising a coloring agent (D 2 ) . The liquid ink composition according to any one of claims 1 to 4 , wherein the polycarboxylic acid is sebacic acid and/or dimer acid. The vinyl chloride-vinyl acetate copolymer resin (B) has a hydroxyl group, the hydroxyl value is 50 to 200 mg equivalent KOH, and the content of the vinyl chloride component in the copolymer resin is 80 to 95% by mass. A liquid ink composition according to any one of claims 1 to 5 . 7. The liquid ink composition according to any one of claims 1 to 6 , wherein the organic solvent (E) does not contain an aromatic group-containing organic solvent and/or a ketone solvent. A printed matter obtained by printing the liquid ink composition according to any one of claims 1 to 7 . A laminated laminate comprising the printed matter according to any one of claims 1 to 8 .