JP2019218453A - Liquid ink composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid ink composition having both adhesion to various functional film substrates and blocking resistance without using a silane coupling agent. A liquid ink composition containing a polyurethane resin (A) and a vinyl chloride vinyl acetate copolymer resin (B) having a hydroxyl group, wherein the polyurethane resin (A) has two or more carbon atoms of 6 or less. A polyurethane resin (a1) using a polycarboxylic acid having a carboxyl group as a reaction raw material and a polyurethane resin (a2) using a polycarboxylic acid having two or more carboxyl groups having 7 or more carbon atoms as a reaction raw material are used in combination. A liquid ink composition characterized by this. [Selection diagram] None

Description

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

  Gravure inks and flexographic inks are widely used for the purpose of imparting aesthetic and functional properties to a printing medium. In the case where the gravure or flexo-printed printing medium is used as a food packaging material among packaging materials, lamination is generally performed. In this case, various printing materials and laminating processes are used depending on the type of the contents and the purpose of use.

  In recent years, packaging materials have been diversified, and the adhesion and blocking resistance of the printing ink to the printing substrate (when the ink-printed film is stored in a wound state, the ink film will The phenomenon of shifting) is becoming more severe year by year, including from the viewpoint of work efficiency. Among them, in recent years, among films used for film packages, high-functional films having various barrier properties tend to increase. These high-performance films are coated with an inorganic or organic barrier coating agent on the surface, and when these high-performance films are used as raw materials for gravure printing or flexographic printing, the adhesion between the film raw materials and the ink is generally low. In many cases, it is hindered as compared with conventional films, and often causes troubles of the blocking phenomenon. These high-performance films exist in a wide variety of applications and applications, such as oxygen barriers that block air to prevent deterioration of contents and water vapor barriers that block water vapor for food and electronic components. In addition, many of them are technically undisclosed, and it is difficult to deal with them compared with general film printing.

  Conventionally, in such a laminated product for flexible packaging, a silane coupling agent was added to a printing ink using a polyurethane resin as a binder, thereby improving the high adhesiveness to a printing medium and the lamination strength. (For example, Patent Document 1: JP-A-2001-2971). However, while the types of high-performance films are diversified, the adhesiveness to a printing medium is still insufficient. It is desired to be able to maintain high adhesion to a wider range of high-performance films.

JP-A-2001-2971

  An object of the present invention is to provide a liquid ink composition having both adhesion to various and diversified functional film substrates and blocking resistance without using a silane coupling agent.

  The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, in a liquid ink composition, a polyurethane resin (A) using a polyester polyol as a reaction raw material and a vinyl chloride-vinyl acetate copolymer resin (B) It has been found that it is effective for solving the problem to use a polyurethane resin (A) in which two kinds of polyurethane resins each having a carboxyl group having a different carbon number as a reaction raw material are used in combination. .

  That is, the present invention is a liquid ink composition containing a polyurethane resin (A) and a vinyl chloride-vinyl acetate copolymer resin (B) having a hydroxyl group, wherein the polyurethane resin (A) has 6 or less carbon atoms and 2 A polyurethane resin (a1) using a polycarboxylic acid having two or more carboxyl groups as a reaction raw material and a polyurethane resin (a2) using a polycarboxylic acid having 7 or more carbon atoms and having two or more carboxyl groups as a reaction raw material. It relates to a liquid ink composition characterized by being used in combination.

  In the present invention, the mass ratio of the polyurethane resin (a1) to the polyurethane resin (a2) may be in a range of (a1) / (a2) = 20/80 to (a1) / (as) = 80/20. The present invention relates to a liquid ink composition.

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

  Further, the present invention further provides a liquid ink composition wherein the polyurethane resin (A) further uses a polyether polyol as a reaction raw material, and the mass ratio of the polyether polyol is 1 to 40% by mass of the total amount of the polyurethane resin (A). About.

  The present invention also relates to a liquid ink composition wherein the polyurethane resin (A) further uses a polyether polyol as a reaction raw material, and the polyether polyol has a number average molecular weight of 100 to 3,500.

  The present invention also provides the liquid ink composition according to any one of the above, further comprising a coloring agent (C) and an organic solvent (D).

  Further, the present invention relates to a liquid ink composition wherein the polycarboxylic acid having 6 or less carbon atoms and having two or more carboxyl groups is any of succinic acid, succinic anhydride, and adipic acid, or a mixture thereof. .

  The present invention also relates to a liquid ink composition wherein the polycarboxylic acid having 7 or more carbon atoms and having two or more carboxyl groups is sebacic acid or dimer acid.

  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 Is from 80 to 95% by mass.

  The present invention also relates to a liquid ink composition wherein the organic solvent (D) does not contain an aromatic organic solvent and / or a ketone-based 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 laminate comprising the printed matter.

  ADVANTAGE OF THE INVENTION According to this invention, the liquid ink composition which has both the adhesiveness with respect to various functional film base materials which are diversified and the blocking resistance can be provided, without using a silane coupling agent.

(Definition of words)
In the present invention, the liquid ink refers to a liquid ink applied to a printing method using a printing plate, such as a gravure ink or a flexographic ink, and is preferably a gravure ink or a flexographic ink. Further, the liquid ink of the present invention does not contain an active energy curable component, that is, a liquid ink which is not reactive with active energy rays.
In the following description, “ink” means “printing ink”. In addition, all “parts” indicate “parts by mass”.

  The present invention provides a liquid ink composition containing a polyurethane resin (A) and a vinyl chloride-vinyl acetate copolymer resin (B), wherein the polyurethane resin (A) has a carbon number of 6 or less and two or more carboxyl groups. Characterized in that a polyurethane resin (a1) using a polycarboxylic acid having a carboxylic acid as a reaction raw material and a polyurethane resin (a2) using a polycarboxylic acid having 7 or more carbon atoms and having two or more carboxyl groups as a reaction raw material are used in combination. Liquid ink composition.

  Specifically, the liquid ink composition of the present invention is obtained by converting the polyurethane resin (A) and the vinyl chloride-vinyl acetate copolymer resin (B) into various organic solvents such as ethyl acetate, methyl ethyl ketone, toluene, and IPA, and optionally water ( C) and various additives are previously mixed using a dispersion stirrer. Water may be added to an organic solvent in advance to be a water-containing organic solvent, or a specific amount of water may be separately added. In the case of a varnish composition, a varnish composition can be obtained by adding various additives while stirring the solution with a dispersion stirrer and further stirring. In the case of an ink composition, the ink composition is obtained by adding the colorant (D) and sufficiently dispersing the same.

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

The polyurethane resin (A) used in the liquid ink composition of the present invention comprises: a polyurethane resin (a1) containing a polycarboxylic acid having 6 or less carbon atoms and having two or more carboxyl groups as a reaction raw material; It is essential to blend two types of polyurethane resins (a2) using a polycarboxylic acid having two or more carboxyl groups as a reaction raw material, and each of the polyurethane resins reacts with a compound having two or more hydroxyl groups. It is obtained.
Polyester polyol can further increase the laminate strength by introducing an ester group to increase the polarity, but uses a polycarboxylic acid having 7 or more carbon atoms and having two or more carboxyl groups as a raw material. By doing so, it is possible to combine moderate flexibility and lamination strength, while using a polycarboxylic acid having 6 or less carbon atoms and having two or more carboxyl groups as a raw material prevents excessive softening of the resin. The anti-blocking property after printing can be improved.

Examples of polycarboxylic acids having 6 or less carbon atoms and having two or more carboxyl groups include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, and anhydrides of these acids. Things can be used.
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, and pimelic acid. , Suberic acid, azelaic acid, sebacic acid, aliphatic dicarboxylic acids such as dimer acid, tricarboxylic acids such as trimellitic acid and anhydrides thereof, benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid and the like. An anhydride or the like can be used.
Among them, a polycarboxylic acid having 6 or less carbon atoms, succinic acid, succinic anhydride, adipic acid, used alone and in combination, as a polycarboxylic acid having 7 or more carbon atoms, sebacic acid, dimer acid alone and its use When used together, it is preferred in that it can achieve both adhesion to a wide variety of films, blocking resistance, and high lamination strength.

  Examples of the compound having two or more hydroxyl groups include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and triethylene glycol. Glycols such as ethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-cyclohexanediol and 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-a Propyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-ethyl-1 Glycols having a branched structure such as 2,6-hexanediol, 3,5-heptanediol, 2-methyl-1,8-octanediol; glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, sorbitol and the like can be used. it can. 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 700 to 7,000, and still more preferably in the range of 800 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" (7.8 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 Book “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 volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass)
Standard sample: A calibration curve was prepared using the following standard polystyrene.

[Standard polystyrene]
"TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation
"TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation
Tosoh Corporation "TSKgel Standard Polystyrene A-5000"
"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

A polyurethane resin (a) containing a polycarboxylic acid having 6 or less carbon atoms and having 2 or more carboxyl groups used as a raw material for reaction in the liquid ink composition of the present invention, and a carboxyl group having 7 or more carbon atoms and 2 or more carboxyl groups Is preferably in the range of (a1) / (a2) = 20/80 to (a1) / (a2) = 80/20 using a polycarboxylic acid having the following formula as a reaction raw material. .
If the mass ratio of the polyurethane resin (a1) to the polyurethane resin (a2) is in the range of (a1) / (a2) = 20/80 to (a1) / (a2) = 80/20, It is possible to maintain adhesion to various functional film substrates which are diversified while suppressing blocking resistance.

  Furthermore, it is more preferable that the polyether polyol is contained in the polyurethane resin (a1) and (a2) in a range of 1 to 40% by mass based on the polyurethane resin. As the polyether polyol, various known ether polyols generally used for producing a polyurethane resin can be used, and one kind or two or more kinds may be used in combination. For example, polymer or copolymer polyether polyols such as ethylene oxide, propylene oxide, and tetrahydrofuran are exemplified. When the amount of the polyether polyol is 1% by mass or more with respect to 100% by mass of the polyurethane resin, the solubility of the urethane resin in ketone, ester, and alcohol-based solvents is good, and the reconstitution of the ink film in the solvent is also good. The solubility is hardly reduced, and the tone reproducibility of the printed matter is hardly deteriorated. When the content is 40% by mass or less, the blocking resistance is hardly reduced.

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

  Examples of the diisocyanate compound used for the polyurethane resin (A) in the liquid ink composition of the present invention include various known aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates generally used in the production of polyurethane resins. Can be 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, -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 1,4-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, Aromatic polyisocyanates such as diisocyanate; tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate 1,3-di (isocyanatomethyl) 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 An aliphatic or alicyclic polyisocyanate such as diisocyanate can be used. These polyisocyanates may be used alone or in combination of two or more. Among them, it is preferable to use aliphatic polyisocyanate and / or alicyclic polyisocyanate from the viewpoint of obtaining appropriate flexibility, and to use isophorone diisocyanate or hexamethylene diisocyanate from the viewpoint of further improving adhesive strength. Is more preferable.

Examples of the chain extender used for the polyurethane resin (A) in the liquid ink composition of the present invention include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4′-diamine. In addition, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, Also amines having a hydroxyl group in the molecule such as hydroxypropyl ethylenediamine, di-2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine Can 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 blocking agent for terminating the reaction. Such compounds include, for example, dialkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol. Furthermore, when it is desired to introduce a carboxyl group into the polyurethane resin, an amino acid such as glycine or L-alanine can be used as a reaction terminator. 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 if necessary, a monovalent active hydrogen compound. For example, a polyester polyol and a combined polyol and a diisocyanate compound are reacted in an isocyanate group excess ratio to obtain a prepolymer having terminal isocyanate groups, and the obtained prepolymer is dissolved in an appropriate solvent, that is, a solvent for a liquid ink. Ester solvents such as ethyl acetate, propyl acetate and butyl acetate; ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone; alcohol solvents such as methanol, ethanol, isopropyl alcohol and n-butanol; toluene, Hydrocarbon-based solvents such as xylene, methylcyclohexane, and ethylcyclohexane; or a two-step method of reacting with a chain extender and / or a terminal blocking agent in a mixed solvent thereof, or a polyester polyol. Le and combination polyol, diisocyanate compound, a chain extender and (or) endblocker is produced by one-step process of reacting at a time in a suitable solvent of the above. Among these methods, the two-stage method is preferred for obtaining a uniform polyurethane resin (A). When the polyurethane resin (A) is produced by a two-step method, the total (equivalent ratio) of amino groups of the chain extender and / or the terminal blocking agent is 1 / 0.9 to 1.3. Is preferably reacted. When the equivalent ratio of the isocyanate group to the amino group is smaller than 1 / 1.3, the chain extender and / or the terminal blocking agent remain unreacted, and the polyurethane resin yellows 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, and more preferably in the range of 15,000 to 95,000. If the weight average molecular weight of the polyurethane resin (A) is 10,000 or more, the blocking resistance of the obtained ink composition, the strength of the printed film, oil resistance, and the like are not easily reduced. The viscosity of the resulting ink composition does not become too high, and the gloss of the printed film is easily maintained. The weight average molecular weight of the polyurethane resin (A) indicates a value obtained by measuring the same as the number average molecular weight of the polyester polyol.
The content of the polyurethane resin (A) with respect to the total amount of the composition used in the liquid ink composition of the present invention is at least 4% by mass with respect to the total amount of the composition from the viewpoint of sufficient adhesion of the ink to a printing medium. From the viewpoints of appropriate ink viscosity and working efficiency during ink production and printing, the content is preferably 25% by mass or less, and more preferably 6 to 15% by mass.

  Further, in the liquid ink composition of the present invention, in addition to the polyurethane resin (A), the vinyl chloride-vinyl acetate copolymer resin (B) having a hydroxyl group is essential, so that the retort suitability is further improved.

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

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

  When the liquid ink composition of the present invention is used as a laminating ink for flexible packaging, adhesiveness, blocking resistance, laminating strength, boil retort suitability, printability, all of these properties must be satisfied. The 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 based on 100 parts by mass of the vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group. When the amount is 80 parts by mass or more, the toughness of the resin film can be maintained and the blocking resistance can be secured. If it is at most 95 parts by mass, the resin film will not be too hard, and the adhesiveness will not easily decrease. The hydroxyl value obtained from vinyl alcohol is preferably from 50 to 200 mgKOH / g. When it is 50 mgKOH / g or more, the solubility in a polar solvent is good, and the printability is easily stabilized. When the content is 200 mgKOH / g or less, the boil and retort suitability can be kept good 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), the drying properties of the ink can be controlled, and especially in gravure printing, a gradation portion having a small amount of ink transfer, which is a characteristic of the gravure printing, can be reproduced beautifully. The amount of the water (C) added is preferably in the range of 0.3 to 10% by mass of the total amount of the ink composition from the viewpoint of improving printability. If the amount of the water is 0.3% by mass or more, the reproducibility of the gradation portion tends to be good without decreasing the effect of suppressing the drying of the ink. When the amount is not more than% by mass, it is possible to suppress a decrease in ink stability.
Further, by adding such water (C), it is possible to reduce the amount of the organic solvent used, which leads to environmental friendliness. The 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 separately added.

  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. As organic pigments, azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethineazo, dictopyrrolopyrrole, isoindoline and the like Pigments. Copper phthalocyanine for indigo ink and C.I. I. Pigment No Yellow 83 is preferably used.

Examples of the inorganic pigment include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, red iron, aluminum, and mica (mica). In addition, a glitter pigment (metashine; Nippon Sheet Glass Co., Ltd.) having glass flakes or massive flakes as a base material and coated with metal or metal oxide can be used. It is preferable to use titanium oxide for the white ink, carbon black for the black ink, aluminum for the gold and silver inks, and mica (mica) for the pearl ink from the viewpoint of cost and coloring power. Aluminum is in powder or paste form, but is preferably used in paste form from the viewpoint of handling and safety. Whether leafing or non-leafing is used is appropriately selected from the viewpoint of brightness and density.
It is preferable that the coloring agent is contained in an amount sufficient to secure the concentration and coloring power of the ink, that is, 1 to 50% by weight based on the total weight of the ink. The coloring agents can be used alone or in combination of two or more.

  Next, the organic solvent (E) used in the present invention will be described. In the ink composition for laminating flexible packaging of the present invention, for example, aromatic organic solvents, acetone, methyl ethyl ketone, ketone solvents such as methyl isobutyl ketone, ethyl acetate, n-propyl acetate, butyl acetate, propylene glycol monomethyl ether acetate and the like Examples include ester solvents, alcohol solvents such as n-propanol, inopropanol, n-butanol, and propylene glycol monomethyl ether, and these can be used alone or in a mixture of two or more. In recent years, from the viewpoint of working environment, it is desirable not to use aromatic solvents such as toluene and xylene and solvents such as ketones.

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

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

  In order to stably disperse the pigment in the organic solvent, the above resin alone can be dispersed, but a dispersant may be used in combination to further stably disperse the pigment. As the dispersant, an anionic, nonionic, cationic, amphoteric or other surfactant can be used. For example, a comb-shaped polymer compound obtained by adding a polyester to polyethyleneimine, or an alkylamine derivative of an α-olefin maleic acid polymer can be used. Specific examples include the Solspers series (ZENECA), the Addisper series (Ajinomoto), and the homogenol series (Kao). Also, BYK series (Big 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 weight or more based on the total weight of the ink from the viewpoint of storage stability of the ink, and 5% by weight or less from the viewpoint of lamination suitability. 0.1 to 2% by weight.

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

The particle size distribution of the pigment in the pigment dispersion is adjusted by appropriately adjusting the size of the pulverizing medium of the disperser, the filling rate of the pulverizing medium, the dispersion processing time, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, and the like. be able to. As the disperser, generally used, for example, a roller mill, a ball mill, a pebble mill, an attritor, a sand mill and the like can be used.
If bubbles or unexpectedly large particles are included in the ink, it is preferable to remove the ink by filtration or the like in order to reduce the quality of the printed matter. A conventionally known filter can be used.

The viscosity of the ink produced by the above method is in a range of not less than 10 mPas from the viewpoint of preventing sedimentation of the pigment and dispersing the pigment appropriately, and not more than 1000 mPas from the viewpoint of work efficiency during ink production and printing. preferable. The viscosity is a viscosity measured at 25 ° C. with a 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. Also, the viscosity of the ink can be adjusted by adjusting the particle size and particle size distribution of the pigment in the ink.

  When the colorant (D) is used in the liquid ink composition of the present invention, the hue may be yellow, red, indigo, indigo, black, or white depending on the type of the colorant (D) used. There are five colors, and there are three colors of red (orange), grass (green), and purple as process gamut outer colors. Further, a transparent yellow, a peony, a vermilion, a brown, a gold, a silver, a pearl, an almost transparent medium for color density adjustment (including an extender if necessary) and the like 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 concentration suitable for gravure printing or flexographic printing, and supplied to each printing unit alone or in a mixture.

The plastic film that can be used as the base material is not particularly limited. Examples thereof include polyamide resins such as Ny6, nylon 66, and nylon 46, polyethylene phthalate (PET), polyethylene naphthalate, polytrimethylene terephthalate, and polytrimethylene naphthalate. Biodegradation typified by polyester resins such as polybutylene terephthalate and polybutylene naphthalate, polyhydroxycarboxylic acids such as polylactic acid, and aliphatic polyester resins such as poly (ethylene succinate) and poly (butylene succinate) Film made of a thermoplastic resin such as a conductive resin, a polyolefin resin such as polypropylene (PP) and polyethylene, a polyimide resin, a polyarylate resin or a mixture thereof, and a laminate of these. Ester, polyamide, polyethylene, of polypropylene film can be suitably used.
These films may be unstretched films or stretched films, and their production methods are not limited. Also, the thickness of the base film is not particularly limited, but usually may be in the range of 1 to 500 μm.
Further, it is preferable that the printed surface of the film is subjected to a corona discharge treatment, since the substrate adhesion can be further improved. Further, silica, alumina, or the like may be deposited.
As a printing method, printing can be performed by a printing method using a known plate such as gravure printing or flexographic printing, but printing by a gravure printing method is particularly preferable. As the cylinder used for gravure printing, a known cylinder such as an engraving type or a corrosion type is used.

The present invention will be described more specifically with reference to examples. Hereinafter, both “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 performed using HLC8220 system manufactured by Tosoh Corporation under the following conditions.
Separation column: Four 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 microliter. Detector: Differential refractometer.
The viscosity was measured at 25 ° C. with a Tokimec B-type viscometer.

[Synthesis of polyurethane resin (a1)]
(Synthesis Example 1) a1-1
In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, 80 parts (hydroxyl value: 57 mgKOH / g) of a polyester polyol made from neopentyl glycol and succinic acid, neopentyl glycol and succinic acid 20 parts of a polyester polyol (hydroxyl value: 110 mgKOH / g) and 22.5 parts of isophorone diisocyanate prepared from an acid are charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to obtain a urethane having an isocyanate group content of 2.84% by mass. After preparing the prepolymer, 66 parts of ethyl acetate was added thereto to obtain a uniform urethane prepolymer solution. Next, the urethane prepolymer solution was added to a mixture consisting 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 mixture was stirred and reacted at 45 ° C. for 5 hours. Thus, a polyurethane resin solution a1-1 was obtained. The obtained polyurethane resin solution a1-1 had a resin solid content concentration of 30.1% by mass and a weight average molecular weight of the resin solid content of 30,000.

(Synthesis Example 2) a1-2
In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas inlet tube, 80 parts (hydroxyl value: 57 mg KOH / g) of a polyester polyol made from neopentyl glycol and adipic acid, neopentyl glycol and adipine 20 parts of a polyester polyol (hydroxyl value: 110 mgKOH / g) and 22.5 parts of isophorone diisocyanate prepared from an acid are charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to obtain a urethane having an isocyanate group content of 2.84% by mass. After preparing the prepolymer, 66 parts of ethyl acetate was added thereto to obtain a uniform urethane prepolymer solution. Next, the urethane prepolymer solution was added to a mixture consisting 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 mixture was stirred and reacted at 45 ° C. for 5 hours. Thus, a polyurethane resin solution a1-2 was obtained. The obtained polyurethane resin solution a1-2 had a resin solid content concentration of 30.1% by mass and a weight average molecular weight of the resin solid content of 30,000.

(Synthesis Example 3) a1-3
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 adipic 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 urethane prepolymer solution. Next, the urethane prepolymer solution was added to a mixture consisting 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 mixture was stirred and reacted at 45 ° C. for 5 hours. Thus, a polyurethane resin solution a1-3 was obtained. The obtained polyurethane resin solution a1-3 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 of polyurethane resin (a2)]
(Synthesis Example 4) a2-1
In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 100 parts of a polyester polyol (hydroxyl value: 108 mgKOH / g) made of neopentyl glycol and sebacic acid and 32.3 of isophorone diisocyanate were used. The mixture was reacted at 90 ° C. for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 3.08% by mass, and then 71.2 parts of ethyl acetate was added thereto to homogenize the urethane prepolymer. The solution was used. Next, the urethane prepolymer solution was added to a mixture consisting 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 mixture was stirred and reacted at 45 ° C. for 5 hours. Thus, a polyurethane resin solution a2-1 was obtained. The obtained polyurethane resin solution a2-1 had a resin solid content concentration of 29.9% by mass and a weight average molecular weight of the resin solid content of 54,000.

(Synthesis Example 5) a2-2
In a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 100 parts of a polyester polyol (hydroxyl value: 122 mg KOH / g) made of neopentyl glycol and dimer acid and hexamethylene diisocyanate 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 68 parts of ethyl acetate was added thereto to obtain a uniform urethane prepolymer solution. And Next, the urethane prepolymer solution was added to a mixture consisting 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 mixture was stirred and reacted at 45 ° C. for 5 hours. Thus, a polyurethane resin solution a2-2 was obtained. The obtained polyurethane resin solution a2-2 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 6) a2-3
In a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube, 90 parts of a polyester polyol (hydroxyl value: 20 mg KOH / g) and 10 parts of polyethylene glycol made from neopentyl glycol and sebacic acid ( (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 urethane prepolymer solution. Next, the urethane prepolymer solution was added to a mixture consisting 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 mixture was stirred and reacted at 45 ° C. for 5 hours. Thus, a polyurethane resin solution a2-3 was obtained. The obtained polyurethane resin solution a2-3 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.

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

[Example 1]
6 parts of the obtained polyurethane resin solution a1-1, 24 parts of the polyurethane resin solution a2-1, 30 parts of a vinyl chloride-vinyl acetate copolymer resin solution A-1 (15% solution) having a hydroxyl group, and a phthalocyanine blue pigment 10 A mixture of 100 parts of FASTGEN Blue LA5380 (manufactured by DIC Corporation), 27 parts of ethyl acetate, and 3 parts of water was kneaded to prepare an indigo printing ink.

[Evaluation item 1: Adhesion to various films]
The viscosity of the obtained liquid indigo ink was adjusted to 16 seconds (25 ° C.) with a mixed solvent of ethyl acetate / isopropyl alcohol = 50/50 (mass ratio) using Zahn Cup # 3 (manufactured by Rigo Co., Ltd.), and the plate depth was 35 μm. The biaxially stretched polyester film U (hereinafter referred to as PET) having a corona treatment on one side and on the vapor deposition side of each of the barrier films (W, X, Y, Z) shown in Tables 1 to 4 by a gravure calibrator equipped with a plate. The film, E-5100 manufactured by Toyobo Co., Ltd., thickness 12 μm), and the biaxially stretched polypropylene film V (hereinafter, OPP film, P2161 manufactured by Toyobo Co., Ltd., thickness 20 μm) are printed on the corona-treated surface side, and the printed matter is printed on the surface. After standing for a day, a cellophane tape (Nichiban 12 mm width) was adhered to the printing surface, and the appearance of the printed film when this was rapidly peeled off was evaluated in the next five steps. It was visually judged on the floor.

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

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

[Evaluation item 2: Blocking resistance]
Films are superimposed so that the printed surface and the non-printed surface of the same printed matter produced by the adhesiveness to various films of evaluation item 1 are in contact with each other, and a weight of 10 kgf / cm ² is applied thereto. After the passage of time, after taking out, the state of transfer of the ink to the non-printing surface was visually evaluated in the following three stages.

：: No transfer was observed at 0% of the amount of ink transferred to the non-printing surface. Δ: Transfer of less than 20% was observed. X: Transfer of 20% or more transferred.

[Examples 1 to 6, Comparative Examples 1 to 6]
Using a polyurethane resin having a configuration shown in Table 1, inks were produced in the same procedure as in Example 1 by the composition of Examples 1 to 6 shown in Table 2 and Comparative Examples 1 to 6 shown in Table 3. .
The results of each evaluation are also shown.

  The liquid ink composition of the present invention has both good adhesion to various functional film substrates and blocking resistance after printing.

  The liquid ink composition of the present invention can be widely used for industrial products such as food packaging materials, sanitary products, cosmetics, and electronic components, for which demands for various film compositions are expected.

Claims (12)

A liquid ink composition containing a polyurethane resin (A) and a vinyl chloride-vinyl acetate copolymer resin (B) having a hydroxyl group, wherein the polyurethane resin (A) has two or more carboxyl groups having 6 or less carbon atoms. A polyurethane resin (a1) using a polycarboxylic acid having the same as a reaction raw material and a polyurethane resin (a2) using a polycarboxylic acid having a carbon number of 7 or more and having two or more carboxyl groups as a reaction raw material. Liquid ink composition.
The mass ratio of the polyurethane resin (a1) and the polyurethane resin (a2) is in the range of (a2) / (a2) = 20/80 to (a1) / (a2) = 80/20. Liquid ink composition.
3. The liquid ink composition according to claim 1, further comprising water in an amount of less than 10% by mass of the total amount of the composition.
The liquid ink composition according to any one of claims 1 to 3, wherein the mass ratio of the polyether polyol is 1 to 40% by mass of the total amount of the polyurethane resin (A).
The liquid ink composition according to any one of claims 1 to 4, wherein the polyether polyol has a number average molecular weight of 100 to 3,500.
The liquid ink composition according to any one of claims 1 to 5, further comprising a colorant (C) and an organic solvent (D).
7. The polycarboxylic acid having 6 or less carbon atoms and having two or more carboxyl groups is succinic acid, succinic anhydride, or adipic acid, or a mixture thereof. Liquid ink composition.
The liquid ink composition according to any one of claims 1 to 7, wherein the polycarboxylic acid having 7 or more carbon atoms and having two or more carboxyl groups is sebacic acid, dimer acid, or a mixture thereof.
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. The liquid ink composition according to any one of claims 1 to 8, wherein
The liquid ink composition according to any one of claims 1 to 9, wherein the organic solvent (D) does not include an aromatic organic solvent and / or a ketone-based solvent.
A printed matter obtained by printing the liquid ink composition according to any one of claims 1 to 10.
  A laminate comprising the printed matter according to claim 11.