JP2020200357A - Liquid ink composition - Google Patents

Abstract

To provide a liquid ink composition having both adhesion to a wide variety of functional film substrates and anti-blocking properties without using a silane coupling agent.SOLUTION: A liquid ink composition includes a polyurethane resin (A) and a vinyl chloride vinyl acetate copolymer resin (B) having a hydroxy group. The polyurethane resin (A) uses a polyurethane resin (a1) using, as a reaction raw material, polycarboxylic acid having two or more carboxyl groups whose number of carbon atoms is 6 or less, together with a polyurethane resin (a2) using, as a reaction raw material, polycarboxylic acid having two or more carboxyl groups whose number of carbon atoms is 7 or more.SELECTED DRAWING: 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 cosmeticity and functionality to a printed object. When the gravure- or flexographic-printed object to be printed is used as a food packaging material among packaging materials, it is generally laminated. In this case, various printed materials and laminating processes are used depending on the type of contents and the purpose of use.

In recent years, packaging materials have been diversified, and the adhesion and blocking resistance of printing ink to the printing substrate (when the film on which the ink is printed is stored in a wound state, the ink film becomes a non-printing surface. The conditions for the transition phenomenon) are becoming stricter year by year, including from the viewpoint of improving work efficiency. Among them, among the films used for film packages in recent years, the number of high-performance films imparted with various barrier properties tends to increase. An inorganic or organic barrier coating agent is applied to the surface of these high-performance films, and when gravure printing or flexographic printing is performed using these high-performance films as raw fabrics, the adhesion between the raw fabrics and the ink is generally good. It is often hindered compared to typical films, and often induces troubles in the blocking phenomenon. These high-performance films exist in a wide variety of applications for foods and electronic parts, such as oxygen barriers that block air to prevent deterioration of the contents and water vapor barriers that block water vapor, depending on the type of industry and purpose. In addition, many of them are technically private, and it is difficult to deal with them compared to general film printing.

Conventionally, in such a laminated product for flexible packaging, by adding a silane coupling agent to a printing ink using a polyurethane resin as a binder, high adhesion to an object to be printed and laminating strength have been improved. It is exemplified (for example, Patent Document 1: Japanese Patent Application Laid-Open No. 2001-2971). However, while the types of high-performance films are diversifying, the adhesiveness to the printed material is still not sufficient. It is desired that high adhesiveness can be maintained for a wider range of high-performance films.

Japanese Unexamined Patent Publication No. 2001-2971

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

As a result of intensive studies to solve the above-mentioned problems, the present inventors have made a polyurethane resin (A) and a vinyl chloride vinyl acetate copolymer resin (B) using a polyester polyol as a reaction raw material in a liquid ink composition. It was found that it is effective to solve the problem that the polyurethane resin (A) is a liquid ink composition containing the above-mentioned materials and it is effective to use two kinds of polyurethane resins using carboxyl groups having different carbon atoms as reaction raw materials in combination. It was.

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. 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 seven or more carbon atoms and having two or more carboxyl groups as a reaction raw material. ) Is used in combination with respect to a liquid ink composition.

Further, in the present invention, the molar ratio of the polyurethane resin (a1) to the polyurethane resin (a2) ranges from (a1) / (a2) = 20/80 to (a1) / (a2) = 80/20. With respect to a liquid ink composition.

The present invention further relates to a liquid ink composition containing less than 10% by mass of water in the total amount of the composition.

Further, in the present invention, 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). Regarding.

The present invention further relates to a liquid ink composition in which 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 3500.

The liquid ink composition according to any one of the present invention, which further contains a colorant (C) and an organic solvent (D).

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

The present invention also relates to a liquid ink composition in which the polycarboxylic acid having 7 or more carbon atoms and having 2 or more carboxyl groups is sebacic acid or dimer acid.

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

The present invention also relates to a liquid ink composition in which the organic solvent (D) does not contain an aromatic 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 made of the printed matter.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a liquid ink composition having both adhesion to various functional film substrates and blocking resistance 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 flexo ink, and is preferably a gravure ink or a flexo ink. Further, the liquid ink of the present invention does not contain an active energy curable component, that is, is an active energy ray non-reactive liquid ink.
The "inks" used in the following description all refer to "printing inks". Moreover, all "parts" indicate "mass parts".

The present invention is a liquid ink composition containing a polyurethane resin (A) and a vinyl chloride vinyl acetate copolymer resin (B), wherein the polyurethane resin (A) has two or more carboxyls having 6 or less carbon atoms. A polyurethane resin (a1) using a polycarboxylic acid having a 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. It is a liquid ink composition characterized by.

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

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 has a polyurethane resin (a1) using a polycarboxylic acid having 6 or less carbon atoms and two or more carboxyl groups as a reaction raw material, and a polyurethane resin (a1) having two or more carbon atoms. It is essential to blend two types of polyurethane resin (a2), which is a polyurethane resin (a2) using a polycarboxylic acid having 7 or more and 2 or more carboxyl groups as a reaction raw material, and each polyurethane resin is a compound having 2 or more hydroxyl groups. Obtained by reacting with.
The polyester polyol can further increase the lamination strength by introducing an ester group to increase the polarity, but the raw material is a polycarboxylic acid having 7 or more carbon atoms and 2 or more carboxyl groups. By doing so, it is possible to obtain both appropriate flexibility and laminate strength, and by using a polycarboxylic acid having 6 or less carbon atoms and two or more carboxyl groups as a raw material, excessive softening of the resin is prevented. It is possible to improve the blocking resistance after printing.

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 anhydrous of these acids. You can use things.
Examples of polycarboxylic acids having 7 or more carbon atoms and 2 or more carboxyl groups include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and anhydrides of these acids, and pimeric acid. , Suberic acid, azelaic acid, sebacic acid, dimeric acid and other aliphatic dicarboxylic acids, trimellitic acid and its anhydrides and other tricarboxylic acids, benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid and these acids. Anhydride or the like can be used.
Among them, the polycarboxylic acid succinic acid having 6 or less carbon atoms, succinic anhydride, and adipic acid are used alone or in combination thereof, and as the polycarboxylic acid having 7 or more carbon atoms, sebacic acid and dimer acid are used alone and the same. When used in combination, it is preferable 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 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 with branched structures such as hexanediol, 2-ethyl-1,6-hexanediol, 3,5-heptanediol, 2-methyl-1,8-octanediol; glycerin, trimethylrolpropane, trimethylolethane, penta Ellisritol, 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 700 to 7,000, and even more preferably in the range of 800 to 6,000. ..
In the present invention, the number average and the weight average molecular weight show the values measured under the following conditions by the gel permeation chromatography (GPC) method.

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

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

A polyurethane resin (a) using a polycarboxylic acid having 6 or less carbon atoms and having two or more carboxyl groups as a reaction raw material used in the liquid ink composition of the present invention and two or more carboxyl groups having 7 or more carbon atoms. The molar ratio of the polyurethane resin (b) using the polycarboxylic acid having the above as a reaction raw material is preferably in the range of (a1) / (a2) = 20/80 to (a1) / (a2) = 80/20. ..
If the molar 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, after printing. While suppressing blocking resistance, it is possible to maintain adhesion to a wide variety of functional film substrates.

Further, it is more preferable that the polyether polyol is contained in the range of 1 to 40% by mass with respect to the polyurethane resin as a constituent component of each of the polyurethane resins (a1) and (a2). As the polyether polyol, various known ether polyols generally used in the production of polyurethane resin can be used, and one kind or two or more kinds may be used in combination. Examples thereof include polyether polyols of polymers such as ethylene oxide, propylene oxide and tetrahydrofuran, or copolymers. When the content of the polyether polyol is 1% by mass or more with respect to 100% by mass of the polyurethane resin, the solubility of the urethane resin in a ketone, ester, or alcohol solvent is good, and the ink film is reconstituted in the solvent. Solubility does not easily decrease, and the tone reproducibility of printed matter does not deteriorate easily. Further, if it is 40% by mass or less, the blocking resistance is unlikely to decrease.

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 film of the polyurethane resin does not become hard and the adhesiveness to the polyester film is less likely to 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 be difficult to decrease.

Examples of the diisocyanate compound used in the polyurethane resin (A) in the liquid ink composition of the present invention include various known aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates generally used in the production of polyurethane resins. Be done. For example, 1,3-phenylenediocyanate, 1,4-phenylenediocyanate, 1-methyl-2,4-phenylenediocyanate, 1-methyl-2,6-phenylenediocyanate, 1-methyl-2,5-phenylenediocyanate, 1 -Methyl-2,6-phenylenediisocyanate, 1-methyl-3,5-phenylenediocyanate, 1-ethyl-2,4-phenylenediocyanate, 1-isopropyl-2,4-phenylenediocyanide, 1,3-dimethyl-2 , 4-phenylenediisocyanis, 1,3-dimethyl-4,6-phenylenediisocyanate, 1,4-dimethyl-2,5-phenylenediisocyanate, diethylbenzene diisocyanate, diisopropylbenzenediisocyanate, 1-methyl-3,5-diethylbenzenediisocyanate, 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'-diisocyanis, 3-3'-dimethylbiphenyl-4,4'-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, diphenylmethane-2,4-diisocyanate and other aromatic polyisocyanes Tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di (isocyanis) Methyl) cyclohexane, 1,4-di (isocyanisethylene methyl) cyclohexane, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexamethylene diisocyanate, 2,4'-dicyclohexamethylene diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 3, 3'-dimethyl-4,4'-dicyclohexylmethane Aliphatic compounds such as diisocyanates or alicyclic polyisocyanates can be used. These polyisocyanates may be used alone or in combination of two or more. Among these, an aliphatic polyisocyanate and / or an alicyclic polyisocyanate is preferably used from the viewpoint of obtaining appropriate flexibility, and isophorone diisocyanate or hexamethylene diisocyanate is used from the viewpoint of further improving the adhesive strength. Is more preferable.

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

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

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

Further, in the liquid ink composition of the present invention, the retort resistance is further improved by requiring the vinyl chloride vinyl acetate copolymer resin (B) having a hydroxyl group in addition to the polyurethane resin (A).

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

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 a vinyl alcohol in an appropriate ratio. The other is obtained by copolymerizing vinyl chloride and vinyl acetate and then partially saponifying the vinyl acetate. In the vinyl chloride vinyl acetate copolymer resin having a hydroxyl group, the properties of the resin film and the resin dissolution behavior are determined by the monomer ratio of vinyl chloride, vinyl acetate and vinyl alcohol. That is, vinyl chloride imparts toughness and hardness of the resin film, 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 performances such as adhesiveness, blocking resistance, laminating strength, boil retort suitability, and printability. Therefore, chloride having a hydroxyl group The vinyl acetate copolymer resin has an appropriate monomer ratio. That is, 80 to 95 parts by mass of vinyl chloride is preferable with respect to 100 parts by mass of the vinyl chloride vinyl acetate copolymer resin having a hydroxyl group. If it is 80 parts by mass or more, the toughness of the resin film can be maintained and blocking resistance can be ensured. If it is 95 parts by mass or less, the resin film does not become too hard and the adhesiveness is unlikely to decrease. 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 a polar solvent is good, and the printability is easily stable. If it is 200 mgKOH / g or less, the water resistance does not decrease and the boil and retort suitability can be kept good.

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 property of the ink can be controlled, and particularly in gravure printing, the gradation portion having a small amount of ink transfer, which is a feature thereof, can be clearly reproduced. The amount of 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. When the amount of water added is 0.3% by mass or more, the reproducibility of the gradation portion tends to be good without reducing the effect of suppressing the drying of the ink, and the amount of water added is 10 of the total amount of the ink composition. If it is mass% or less, it is possible to suppress a decrease in ink stability.
Further, by adding such water (C), it is possible to reduce the organic solvent component 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 colorant (D) used in the present invention include organic and inorganic pigments and dyes used in general inks, paints, recording agents and the like. Organic pigments include azo-based, phthalocyanine-based, anthraquinone-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine-azo-based, dictopyrrolopyrrole-based, and isoindoline-based. Pigments can be mentioned. Copper phthalocyanine for indigo ink and C.I. for transparent yellow ink in terms of cost and light resistance. I. It is preferable to use Pigment No Yellow 83.

Examples of the inorganic pigment include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, red iron oxide, aluminum, mica (mica) and the like. Further, a brilliant pigment (Metashine; Nippon Sheet Glass Co., Ltd.) in which a metal or a metal oxide is coated on a glass flake or a lump flake as a base material can be used. It is preferable to use titanium oxide for white ink, carbon black for black ink, aluminum for gold and silver ink, and mica (mica) for pearl ink from the viewpoint of cost and coloring power. Although aluminum is in the form of powder or paste, it is preferably used in the form of paste from the viewpoint of handleability and safety, and whether to use leafing or non-leafing is appropriately selected from the viewpoint of brightness and concentration.
The colorant is preferably contained in an amount sufficient to secure 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. In addition, the colorants 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 liquid ink composition of the present invention, for example, an aromatic organic solvent, a ketone solvent such as acetone, methyl ethyl ketone, methyl isobutyl ketone, an ester solvent such as ethyl acetate, n-propyl acetate, butyl acetate, propylene glycol monomethyl ether acetate, etc. Examples thereof include alcohol solvents such as n-propanol, inopropanol, n-butanol, and propylene glycol monomethyl ether, which can be used alone or in admixture 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 of ketones.

Examples of resins used in combination with the liquid ink composition of the present invention as necessary include resins other than the polyurethane resin and vinyl chloride-vinyl acetate copolymer resin, for example, chlorinated polypropylene resin and ethylene-vinyl acetate copolymer weight. Combined resin, vinyl acetate resin, polyamide resin, acrylic resin, polyester resin, alkyd resin, polyvinyl chloride resin, rosin resin, rosin-modified maleic acid resin, ketone resin, cyclized rubber, rubber chloride, 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, if necessary, a combined resin, extender pigment, pigment dispersant, leveling agent, defoamer, wax, plasticizer, infrared absorber, ultraviolet absorber, fragrance, flame retardant and the like can also be included. ..

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

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

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

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

When the colorant (D) is used in the liquid ink composition of the present invention, the hue may be yellow, red, indigo, ink, or white depending on the type of the colorant (D) used. There are 5 colors, and there are 3 colors of red (orange), grass (green), and purple as the outer color of the process gamut. Furthermore, transparent yellow, peony, vermilion, brown, gold, silver, pearl, and almost transparent medium for adjusting the color density (including extender pigment if necessary) are prepared as base colors. The ink for boil retort is appropriately selected in consideration of pigment migration and heat resistance. The base ink of each hue is diluted with a diluting solvent to a viscosity and concentration suitable for gravure printing or flexographic printing, and is supplied to each printing unit alone or mixed.

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

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

[Synthesis of polyurethane resin (a1)]
(Synthesis Example 1) a1-1
80 parts of polyester polyol (hydroxyl value: 57 mgKOH / g) made from neopentyl glycol and succinic acid, neopentyl glycol and succinate in a four-necked flask equipped with a stirrer, thermometer, recirculation cooler and nitrogen gas introduction tube. 20 parts of polyester polyol (hydroxyl value: 110 mgKOH / g) made from acid and 22.5 parts of isophorone diisocyanate are charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to urethane having an isocyanate group content of 2.84% by mass. After producing the prepolymer, 66 parts of ethyl acetate was added thereto to prepare a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 7.25 parts of isophorone diamine, 0.27 parts of di-n-butylamine, 131 parts of ethyl acetate and 106 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. The polyurethane resin solution 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
80 parts of polyester polyol (hydroxyl value: 57 mgKOH / g) made from neopentyl glycol and adipic acid, neopentyl glycol and adipine in a four-necked flask equipped with a stirrer, thermometer, recirculation cooler and nitrogen gas introduction tube. 20 parts of polyester polyol (hydroxyl value: 110 mgKOH / g) made from acid and 22.5 parts of isophorone diisocyanate are charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to urethane having an isocyanate group content of 2.84% by mass. After producing the prepolymer, 66 parts of ethyl acetate was added thereto to prepare a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 7.25 parts of isophorone diamine, 0.27 parts of di-n-butylamine, 131 parts of ethyl acetate and 106 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. The polyurethane resin solution 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
90 parts of polyester polyol (hydroxyl value: 20 mgKOH / g) and 10 parts of polyethylene glycol (hydroxyl value: 20 mgKOH / g) made from neopentyl glycol and adipic acid in a 4-port flask equipped with a stirrer, thermometer, recirculation cooler and nitrogen gas introduction tube. Hydroxy group value: 56 mgKOH / 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, and then acetic acid. 61.5 parts of ethyl was added to make a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 7.09 parts of isophorone diamine, 0.92 parts of di-n-butylamine, 124 parts of ethyl acetate and 100 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. The polyurethane resin solution 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
100 parts of polyester polyol (hydroxyl value: 108 mgKOH / g) and isophorone diisocyanate 32.3 made from neopentyl glycol and sebacic acid in a four-necked flask equipped with a stirrer, thermometer, recirculation cooler and nitrogen gas introduction tube. Parts are charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 3.08% by mass, and then 71.2 parts of ethyl acetate is added thereto to make the urethane prepolymer uniform. It was made into a solution. Next, the urethane prepolymer solution was added to a mixture consisting of 8.47 parts of isophorone diamine, 0.46 parts of di-n-butylamine, 143 parts of ethyl acetate and 115 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. To obtain a polyurethane resin solution a2-1. 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
100 parts of polyester polyol (hydroxyl value: 122 mgKOH / g) made from neopentyl glycol and dimer acid and hexamethylene diisocyanate in a four-necked flask equipped with a stirrer, a thermometer, a recirculation cooler and a nitrogen gas introduction tube. Three 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 then 68 parts of ethyl acetate was added thereto to form a uniform solution of the urethane prepolymer. And said. Next, the urethane prepolymer solution was added to a mixture consisting of 8.09 parts of isophorone diamine, 0.38 parts of di-n-butylamine, 136 parts of ethyl acetate and 110 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. To obtain a polyurethane resin solution a2-2. 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
90 parts of polyester polyol (hydroxyl value: 20 mgKOH / g) and 10 parts of polyethylene glycol (hydroxyl value: 20 mgKOH / g) made from neopentyl glycol and sebacic acid in a four-necked flask equipped with a stirrer, thermometer, recirculation cooler and nitrogen gas introduction tube. Hydroxy group value: 56 mgKOH / 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, and then acetic acid. 61.5 parts of ethyl was added to make a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 7.09 parts of isophorone diamine, 0.92 parts of di-n-butylamine, 124 parts of ethyl acetate and 100 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 ° C. for 5 hours. The polyurethane resin solution 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)
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 resin monomer composition by weight%) is acetic acid. A 15% solution was made with ethyl, which was made into a vinyl 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 vinyl chloride vinyl chloride copolymer resin solution A-1 having a hydroxyl group (15% solution), 10 phthalocyanine blue pigments A total of 100 parts of a mixture of parts (FASTGEN Blue LA5380 manufactured by DIC Co., Ltd.), 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 Zahn Cup # 3 (manufactured by Rigosha) with a mixed solvent of ethyl acetate / isopropyl alcohol = 50/50 (mass ratio), and the plate depth was 35 μm gravure. A biaxially stretched polyester film U (hereinafter referred to as PET) in which various barrier films (W, X, Y, Z) shown in Tables 1 to 4 are subjected to corona treatment on the vapor-deposited side and one side by a gravure calibrator equipped with a plate. For the film, E-5100 manufactured by Toyo Spinning Co., Ltd. (thickness 12 μm) and biaxially stretched polypropylene film V (hereinafter, OPP film, manufactured by Toyo Spinning Co., Ltd. P2161 thickness 20 μm), print on the corona-treated surface side, and print 1 After being left for a day, a cellophane tape (12 mm width made by Nichiban) was attached to the printed surface, and the appearance of the printed film when the tape was rapidly peeled off was visually judged in the following five stages.

5: The print film did not peel off at all.
4: More than 70% to less than 90% of the printed film remained on the film.
3: More than 50% to less than 70% of the printed film remained on the film.
2: More than 30% to less than 50% of the printed film remained on the film.
1: The print film remained less than 30%.

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

[Evaluation item 2: Blocking resistance]
The films were laminated so that the printed surface and the non-printed surface of the same printed matter produced by the adhesion to various films of the evaluation item 1 were in contact with each other, and a load of 10 kgf / cm ² was applied for 12 hours in an environment of 40 ° C. After aging and taking out, the state of ink transfer to the non-printed surface was visually evaluated in the following three stages.

◯: No transfer is observed when the amount of ink transferred to the non-printed surface is 0% Δ: Less than 20% of the transfer is observed ×: 20% or more of the transfer amount is transferred

[Examples 1 to 6 and Comparative Examples 1 to 6]
Using the polyurethane resin having the composition shown in Table 1, ink was prepared in the same procedure as in Example 1 by blending the compositions 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 adhesion to a wide variety of functional film substrates and blocking resistance after printing.

The liquid ink composition of the present invention can be widely applied to industrial products such as food packaging materials, sanitary products, cosmetics, and electronic parts, for which demand for a wide variety of film configurations is 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 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 can be used in combination. A characteristic liquid ink composition.
The first aspect of claim 1, wherein the molar 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. Liquid ink composition.
The liquid ink composition according to claim 1 or 2, further comprising water in an amount of less than 10% by mass based on the total amount of the composition.
The invention according to any one of claims 1 to 3, 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). Liquid ink composition.
The liquid ink composition according to any one of claims 1 to 4, 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 3500.
The liquid ink composition according to any one of claims 1 to 5, further comprising a colorant (C) and an organic solvent (D).
The polycarboxylic acid having 6 or less carbon atoms and having two or more carboxyl groups is any one of succinic acid, succinic anhydride, adipic acid, or a mixture thereof, according to any one of claims 1 to 6. The liquid ink composition described.
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 2 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 thereof 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.
The liquid ink composition according to any one of claims 1 to 9, wherein the organic solvent (D) does not contain an aromatic 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 10.
A laminated laminate composed of the printed matter according to claim 11.