JP7608147B2 - Liquid printing inks, printed matter and laminates - Google Patents

Description

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

In addition to traditional paper cup containers for food, such as yogurt and milk cartons, in recent years, packaging materials for food, confectionery, household goods, pet food, and industrial products that have previously been made of plastic film are increasingly being replaced by packaging materials that combine paper, from the perspective of environmental issues.
Among these, many of them, particularly those intended for storing liquids or liquid-like substances, have a structure in which both sides of the paper are laminated with polyolefin film to prevent leakage of the contents. The paper itself is also acid-resistant and further treated with a sizing agent to enhance its water resistance.

These packaging materials are subjected to gravure printing or flexographic printing to impart designs and messages to the materials in order to appeal to consumers for sales promotion.
In the printing configuration used for such printing, after direct printing on paper, the printed surface is generally subjected to dry lamination processing using an adhesive, extrusion lamination processing using an anchor coating agent, etc. Therefore, the liquid printing inks used, such as gravure printing inks and flexographic printing inks, are required to have various suitabilities after extrusion lamination processing in addition to printability on acid-resistant paper.

Moreover, in recent years, there has been a demand for biomass packaging materials, and printing inks used on packaging materials are also being required to use biomass materials rather than 100% petroleum-derived materials. There is a growing movement to improve various printing properties themselves by using biomass materials.

As a printing ink suitable for the above printing, for example, Patent Document 1 discloses a paper gravure rotary printing ink composition containing a binder resin containing a vinyl chloride-vinyl acetate copolymer and an acrylic resin, and a specific amount of glycerin. The ink composition uses a specific amount of glycerin as an additive to prevent the ink from penetrating into highly hydrophobic base paper, and provides excellent lamination strength to laminated products even when printed on highly hydrophobic base paper.
However, even with this composition, the laminate strength sometimes does not meet the requirements. Furthermore, these inks do not take into account the possibility of improving the properties with biomass raw materials.

JP 2013-213111 A

The problem that this invention aims to solve is to provide a liquid printing ink that is particularly suitable for paper-film composite packaging materials in which a film is laminated after printing directly on paper, that has adhesion, stability over time, resistance to offset, and lamination strength, and that is improved with biomass raw materials.

As a result of intensive research by the inventors to solve the above problems, they discovered that the above problems can be solved by a liquid printing ink containing vinyl chloride-vinyl acetate copolymer resin and acrylic resin as the main binder resins and an organic solvent, containing specific amounts of the vinyl chloride-vinyl acetate copolymer resin, a specific rosin resin, and a chelate compound, and by setting the boiling point of some of the high boiling point solvent to 200°C or higher, thereby completing the present invention.

That is, the present invention relates to a liquid printing ink containing a vinyl chloride-vinyl acetate copolymer resin and an acrylic resin as a main binder resin and an organic solvent, and characterized in that the liquid printing ink satisfies the following requirements:
(1) The ink contains 1 to 12% by mass of vinyl chloride-vinyl isobutyl ether copolymer resin based on the total solids content of the ink.
(2) The ink contains a rosin-based resin having an acid value of 190 mgKOH/g or less and a softening point of 160° C. or less in an amount of 1 to 25% by mass based on the total solids content of the ink.
(3) The ink contains a chelating compound in an amount of 1 to 10% by mass based on the total solid content of the ink.
(4) Contains an organic solvent with a boiling point of 200°C or higher.

The present invention also relates to a liquid printing ink in which the chelate compound is a titanium chelate compound.

The present invention also relates to a printed matter produced by printing with the liquid printing ink.

The present invention also relates to a paper print produced by printing the liquid printing ink on paper.

The present invention also relates to a laminate in which a polyolefin layer is extrusion laminated onto the paper print.

The liquid printing ink of the present invention has excellent adhesion, stability over time and resistance to offset, and has excellent lamination strength, particularly when used with paper-film composite packaging materials in which paper is directly printed and then laminated with a film.
Moreover, because rosin-based resins are natural materials, they can also contribute to the movement to improve the use of biomass raw materials.

(Definition of words)
In the present invention, the liquid printing ink refers to a liquid ink such as gravure ink or flexographic ink that is applied to a printing method using a printing plate, and is preferably gravure ink or flexographic ink. The liquid printing ink of the present invention does not contain an active energy curable component, i.e., is an active energy ray non-reactive liquid ink.
In the present invention, all "parts" refer to "parts by mass,""total amount of ink" refers to the total amount of ink including all volatile components such as organic solvents, and "total amount of ink solids" refers to the total amount of only non-volatile components, excluding volatile components.

(Binder resin)
The binder resin used in the present invention is vinyl chloride-vinyl acetate copolymer resin and acrylic resin as main binder resins, and in addition,
(1) The ink contains 1 to 12 mass % of vinyl chloride-vinyl isobutyl ether copolymer resin based on the total solids content of the ink.
(2) The ink contains a rosin-based resin having an acid value of 190 mgKOH/g or less and a softening point of 160° C. or less in an amount of 1 to 25% by mass based on the total solids content of the ink.
This is a characteristic of the site.

(Vinyl chloride-vinyl acetate copolymer resin)
The vinyl chloride-vinyl acetate copolymer resin is not particularly limited as long as it is a copolymer of vinyl chloride and vinyl acetate. The molecular weight is preferably 5,000 to 100,000 in weight average molecular weight, more preferably 10,000 to 70,000. In 100% by mass of the solid content of the vinyl chloride-vinyl acetate copolymer resin, the structure derived from vinyl acetate monomer is preferably 1 to 30% by mass, and the structure derived from vinyl chloride monomer is preferably 70 to 95% by mass. In this case, the solubility in organic solvents is improved, and further, the adhesion to the substrate, the coating properties, the scratch resistance, etc. are improved.
From the viewpoint of solubility in organic solvents, it is also preferable that the polyvinyl alcohol contains a hydroxyl group derived from a vinyl alcohol structure. The hydroxyl value is preferably 20 to 200 mgKOH/g. The glass transition temperature is preferably 50°C to 90°C.
The amount of vinyl chloride-vinyl acetate copolymer resin added is 5 to 20% by mass, preferably 10 to 15% by mass, based on the ink solids content. Vinyl chloride-vinyl acetate copolymer resin contributes particularly to the lamination strength of the ink, and it is particularly effective to add it in this range.

(Acrylic resin)
The acrylic resin is not particularly limited as long as it is a copolymer of a polymerizable monomer mainly composed of a (meth)acrylic acid ester. Examples of the polymerizable monomer include alkyl ester compounds of (meth)acrylic acid such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, decyl (meth)acrylate, and lauryl (meth)acrylate, (meth)acrylic acid amide derivatives containing at least one N-substituted methylol group such as N-methylol (meth)acrylamide, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, dipropylaminoethyl (meth)acrylate, and dimethylaminopropyl. Examples of the monomer include (meth)acrylate, aminoalkyl esters of (meth)acrylic acid such as diethylaminopropyl (meth)acrylate and dipropylaminopropyl (meth)acrylate, mono- or diesters of (meth)acrylic acid of glycols such as diethylene glycol and dipropylene glycol, styrene derivatives such as styrene and α-methylstyrene, hydroxyalkyl ester compounds of (meth)acrylic acid such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate and 3-hydroxypropyl (meth)acrylate, and vinyl compounds having an acid group such as acrylic acid, methacrylic acid, maleic acid and itaconic acid. The polymerization method is not particularly limited, and those obtained by known methods such as bulk polymerization, solution polymerization, emulsion polymerization and suspension polymerization can be used.
The weight average molecular weight of the acrylic resin is preferably in the range of 5,000 to 200,000, and more preferably in the range of 10,000 to 100,000.
The amount of acrylic resin added is 10 to 50% by mass, preferably 30 to 40% by mass, based on the solid content of the ink. The acrylic resin contributes particularly to the ink's anti-offset properties and adhesion to acid-resistant paper, and it is particularly effective to add the acrylic resin in this range.

(Vinyl chloride-vinyl isobutyl ether copolymer resin)
The vinyl chloride-vinyl isobutyl ether copolymer resin used in the present invention is not particularly limited as long as it is a copolymer of vinyl chloride and vinyl isobutyl ether. The molecular weight is preferably 5,000 to 100,000 in weight average molecular weight, more preferably 10,000 to 70,000. In 100% by mass of the solid content of the vinyl chloride-vinyl isobutyl ether copolymer resin, the structure derived from vinyl isobutyl ether is preferably 1 to 30% by mass, and the structure derived from vinyl chloride monomer is preferably 70 to 95% by mass.
The amount of vinyl chloride-vinyl isobutyl ether copolymer resin added is 1 to 12% by mass relative to the ink solid content as described above, and preferably 4 to 8% by mass. Vinyl chloride-vinyl isobutyl ether copolymer resin contributes particularly to improving the lamination strength of the ink as well as the gloss of the printed matter, and it is particularly effective to add it in this range.

(rosin resin)
The rosin resin used in the present invention is not particularly limited as long as it has an acid value of 190 mgKOH/g or less and a softening point of 160°C or less, and rosin and/or rosin derivatives that are commonly used for printing inks can be used. Specifically, rosin or rosin derivatives are rosins or carboxyl group-containing derivatives thereof. Rosins include gum rosin, wood rosin, tall oil rosin, disproportionated rosin, hydrogenated rosin, and polymers thereof. Rosin derivatives include carboxyl group-containing derivatives such as rosin derivatives to which unsaturated carboxylic acids such as maleic acid, fumaric acid, itaconic acid, crotonic acid, etc. have been added.
The acid value of the rosin-based resin is preferably 100 mgKOH/g or less, and more preferably 50 mgKOH/g or less. On the other hand, there is no particular lower limit, but as long as it is 20 mgKOH/g or more, it can be used without any particular limit.

In the present invention, it is preferable to use a rosin-modified maleic acid resin, which is a maleic acid derivative of rosin, or a rosin-modified fumaric acid resin, which is a fumaric acid derivative of rosin. The rosin-modified maleic acid resin or rosin-modified fumaric acid resin used in the present invention is not particularly limited, and any known rosin-modified maleic acid resin or rosin-modified fumaric acid resin can be used. The rosin-modified maleic acid resin or rosin-modified fumaric acid resin preferably has an acid value of 25 mgKOH/g or more and 320 mgKOH/g or less, and particularly preferably has an acid value of 100 mgKOH/g or more and 320 mgKOH/g or less.
The amount of the rosin resin added is preferably 1 to 25% by mass, and more preferably 5 to 15% by mass, based on the ink solids content.

Commercially available rosin-based resins include Marquid No. 1, 2, 5, 6, 8, 31, 32, 33, 34, 3002, etc. manufactured by Arakawa Chemical Industries Co., Ltd., and Harima Chemical Co., Ltd.'s Harimac R-80, T-80, R-100, M-453, M-130A, 135GN, 145P, R-120AH, Haritac 4851, 4821, 4740, 28JA, etc.

In the present invention, there are no particular limitations other than the blending of the vinyl chloride-vinyl acetate copolymer resin, the acrylic resin, the vinyl chloride-vinyl isobutyl ether copolymer resin, and the rosin-based resin in predetermined amounts, and known binder resins can also be used in combination. Examples include cellulose-based resins such as cellulose acetate propionate (CAP) and cellulose acetate butyronate (CAB), polyurethane resins, polyamide-based resins, chlorinated polypropylene resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, and vinyl chloride-based resins such as polyvinyl chloride resins, polyester resins, alkyd resins, ketone resins, cyclized rubber, chlorinated rubber, butyral, and petroleum resins.

(Cellulose-based resin)
Examples of cellulose resins include cellulose acetate propionate, cellulose acetate butyrate and other cellulose ester resins, nitrocellulose (also called soluble cellulose), hydroxyalkylcellulose, and carboxyalkylcellulose. The cellulose ester resin preferably has an alkyl group, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, and a hexyl group, and the alkyl group may further have a substituent.
Of the above, the cellulose-based resin is preferably cellulose acetate propionate, cellulose acetate butyrate, or nitrocellulose. Nitrocellulose is particularly preferred. The molecular weight is preferably 5,000 to 200,000 in weight average molecular weight, more preferably 10,000 to 50,000. Also, the glass transition temperature is preferably 120°C to 180°C. When used in combination with the polyurethane resin (A) of the present invention, it is expected that the blocking resistance, scratch resistance, and other physical properties of the ink film will be improved.
Nitrocellulose (soluble nitrocellulose) is preferably obtained by reacting natural cellulose with nitric acid to replace three hydroxyl groups in the six-membered ring of the anhydrous glucopyranose group in the natural cellulose with nitric acid groups to produce a nitric acid ester.

The use of nitrocellulose (nitrocellulose) provides high dispersibility in pigments, and is therefore particularly suitable for use as a coating agent for surface printing, as it can improve the strength of the printing ink coating. The nitrocellulose (nitrocellulose) preferably has a nitrogen content of 10 to 13% by mass and an average degree of polymerization of 30 to 500, and more preferably has a nitrogen content of 10 to 13% by mass and an average degree of polymerization of 45 to 290.

The amount of nitrocellulose (soluble cellulose) added is 0.1 to 5% by mass, preferably 0.5 to 2% by mass, based on the ink solids.

(Polyurethane resin)
The polyurethane resin is not particularly limited as long as it is a polyurethane resin obtained by reacting a polyol with a polyisocyanate. As the polyol, for example, various known polyols generally used in the production of polyurethane resins can be used, and one or more kinds may be used in combination. For example, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5 pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, dipropionate, etc. Saturated or unsaturated low molecular weight polyols (1), such as ethylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, and pentaerythritol; these low molecular weight polyols (1) and sebacic acid, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, and trimellitic acid. polyester polyols (2) obtained by dehydration condensation or polymerization of polyvalent carboxylic acids such as pyromellitic acid or their anhydrides; polyester polyols (3) obtained by ring-opening polymerization of cyclic ester compounds, for example lactones such as polycaprolactone, polyvalerolactone, poly(β-methyl-γ-valerolactone); polycarbonate polyols (4) obtained by reacting the low molecular weight polyols (1) or the like with, for example, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, or the like; polybutadiene glycols (5); glycols (6) obtained by adding ethylene oxide or propylene oxide to bisphenol A; and acrylic polyols (7) obtained by copolymerizing, in one molecule, one or more hydroxyethyl groups, hydroxypropyl acrylate, hydroxybutyl acrylate, or the like, or the corresponding methacrylic acid derivatives, with, for example, acrylic acid, methacrylic acid, or an ester thereof.

Examples of polyisocyanates include various known aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates that are commonly used in the production of polyurethane resins. For example, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-2,5-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene diisocyanate, 1-isopropyl-2,4-phenylene diisocyanate, 1,3-dimethyl-2,4-phenylene diisocyanate, 1,3-dimethyl-4,6-phenylene diisocyanate, etc. anate, 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, Aromatic polyisocyanates such as 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, and diphenylmethane-2,4-diisocyanate; tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, and 1,3-cyclopentylene diisocyanate. , 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di(isocyanatemethyl)cyclohexane, 1,4-di(isocyanatemethyl)cyclohexane, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate, and other aliphatic or alicyclic polyisocyanates can be used. These polyisocyanates may be used alone or in combination of two or more. Among these, these diisocyanate compounds can be used alone or in a mixture of two or more.

Chain extenders can also be used. Examples of chain extenders include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, and the like. In addition, amines having a hydroxyl group in the molecule, such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine, can also be used. These chain extenders can be used alone or in combination of two or more.

Furthermore, a monovalent active hydrogen compound can be used as a terminal blocking agent for the purpose of stopping the reaction. Examples of such compounds include dialkylamines such as di-n-butylamine, and alcohols such as ethanol and isopropyl alcohol. Furthermore, when it is particularly desired to introduce a carboxyl group into the polyurethane resin, amino acids such as glycine and L-alanine can be used as a reaction stopping agent. These terminal blocking agents can be used alone or in combination of two or more.
The weight average molecular weight of the polyurethane resin is preferably in the range of 10,000 to 100,000, and more preferably in the range of 15,000 to 80,000.
The amount of polyurethane resin added is preferably 0.1 to 30% by mass, and more preferably 5 to 15% by mass, based on the total amount of the ink.

(polyester resin)
The polyester resin is not particularly limited as long as it is a polyester resin obtained by reacting an alcohol with a carboxylic acid using a known esterification polymerization reaction.
Examples of the alcohol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-butyl-1,3propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,2-pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, pentaerythritol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, spiroglycol, and isosorbide. These may be used alone or in combination of two or more. Among these, polyfunctional alcohols are preferred.
Examples of the carboxylic acid include formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oleic acid, linoleic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, and 1,4-cyclohexanedicarboxylic acid. These may be used alone or in combination of two or more. Among these, polyfunctional carboxylic acids are preferred.
The weight average molecular weight of the polyester resin is preferably 500 to 6000, more preferably 1400 to 5500. The amount of the polyester resin added is preferably 0.15 to 40% by mass, more preferably 1.0 to 35% by mass, based on the total amount of the ink.

(Chlorinated polyolefin resin)
The chlorinated polyolefin resin used in the present invention is not particularly limited as long as it is a polyolefin resin in which at least a part of hydrogen atoms is replaced by chlorine atoms. The weight average molecular weight of the chlorinated polyolefin is preferably 5,000 to 100,000, more preferably 5,000 to 70,000, and even more preferably 7,000 to 50,000. In addition, the chlorine content of the chlorinated polyolefin resin is preferably 25 to 45% by mass in order to improve adhesion to the substrate. In addition, from the viewpoint of solubility in organic solvents, the chlorine content is more preferably 26 to 43% by mass. Here, the chlorine content refers to the mass % of chlorine atoms in 100% by mass of the chlorinated polyolefin resin. In addition, from the viewpoint of balance with blocking resistance, the chlorinated polyolefin resin is contained in the ink solid content of 0.1 to 30% by mass, preferably 1 to 10% by mass.

Chlorinated polyolefin resins have flexible alkyl groups as branched structures, making them flexible even at low temperatures and contributing to improved adhesion to substrates. There are no particular limitations on the structure of the polyolefin resin in the chlorinated polyolefin resin. For example, resins containing homopolymers or copolymers of α-olefin-based unsaturated hydrocarbons such as polypropylene, poly-1-butene, and poly-4-methyl-1-pentene are preferred. Among these, chlorinated polypropylene resins containing a polypropylene structure (i.e., a chlorinated polypropylene structure) are particularly preferred.

(Vinyl resin)
Furthermore, vinyl resins other than the vinyl chloride-vinyl acetate copolymer resin and the vinyl chloride-vinyl isobutyl ether copolymer resin may be used. For example, vinyl chloride resins such as polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene chloride, chlorinated polyethylene, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride-styrene copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-styrene-maleic anhydride terpolymer, vinyl chloride-styrene-acrylonitrile copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-isoprene copolymer, vinyl chloride-chlorinated propylene copolymer, vinyl chloride-vinylidene chloride-vinyl acetate terpolymer, vinyl chloride-maleic acid ester copolymer, vinyl chloride-methacrylic acid ester copolymer, vinyl chloride-acrylonitrile copolymer, vinyl chloride-various vinyl ether copolymer, and blends thereof or other chlorine-free synthetic resins such as acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl (meth)acrylate copolymer, blends with polyester, block copolymers, graft copolymers, and the like can be mentioned. These vinyl chloride resins may be used in mixtures of two or more kinds, or may be used in mixtures with other synthetic resins.

The vinyl acetate resin is a copolymer of vinyl acetate monomer alone or a copolymer of vinyl acetate monomer and a polymerizable unsaturated monomer. Examples of unsaturated monomers include long-chain (meth)acrylic monomers such as alkyl (meth)acrylate monomers, such as n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate; hydroxyl group-containing (meth)acrylic monomers, such as 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 1,4-butanediol mono(meth)acrylate, and (poly)ethylene glycol mono(meth)acrylate; carboxyl group-containing monomers, such as (meth)acrylic acid, maleic acid, and maleic anhydride; vinyl monomers, such as styrene, acrylonitrile, and vinyl chloride; and ethylene. These may be used alone or in combination of two or more.

The molecular weight of the vinyl resin is preferably 5,000 to 100,000, more preferably 10,000 to 70,000, in terms of weight average molecular weight.
The amount of vinyl resin added is 1 to 30% by mass, preferably 10 to 15% by mass, based on the ink solid content.

(Hardening agent)
A hardener may be used in combination with the binder resin. The hardener may be any hardener generally used in organic solvent-based gravure inks, but the most commonly used hardener is an isocyanate-based hardener.
The amount of the isocyanate compound added is preferably in the range of 0.3% by mass to 10.0% by mass, and more preferably 1.0% by mass to 7.0% by mass, based on the solid content of the liquid printing ink, from the viewpoint of curing efficiency.
The total amount of the binder resin is preferably in the range of 0.15 to 50% by mass, and most preferably in the range of 1 to 40% by mass, based on the ink solids content.

(Chelate Compounds)
The present invention is characterized in that the chelate compound is contained in an amount of 1 to 4 mass % based on the total solid content of the ink. By containing the chelate compound in this range, a balance with the rosin-based resin added for biomass contribution can be achieved, resulting in an ink with improved lamination strength and ink offset.

The chelating agent is preferably a metal chelating agent. As the metal chelating agent, a titanium-based chelating agent, a zirconium-based chelating agent, or an aluminum-based chelating agent can be used. Among them, a titanium-based chelating agent is preferable.
Titanium-based chelating agents are classified into alkoxides, acylates, and chelate complexes, but as the chelating agent used in the present invention, chelate complexes are more preferable than alkoxides and acylates, and specific examples of chelate complexes include titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetoacetate, and phosphate titanium complexes. The titanium ethylacetoacetate and phosphate titanium complexes can be free of acetylacetone and are therefore safer. Among these, titanium chelate complexes are preferred.
The content is more preferably 1 to 10% by mass, and most preferably 2 to 6% by mass, based on the total solid content of the ink.

(Organic solvent)
The organic solvent used in the liquid printing ink of the present invention preferably contains an organic solvent having a boiling point of 200° C. or higher. An organic solvent having a boiling point of 200° C. or higher does not volatilize, making it possible to suppress penetration into highly hydrophobic paper substrates such as acid-resistant paper.
Examples of organic solvents having a boiling point of 200° C. or higher include glycerol (290° C.), diethylene glycol monobutyl ether (271° C.), triethylene glycol monomethyl ether (249° C.), triethylene glycol dimethyl ether (216° C.), and diethylene glycol monoisopropyl ether (207° C.).
Among these, glycerol (also called glycerin) is particularly preferred. The amount of glycerol added is 1 to 20% by mass, preferably 5 to 10% by mass, based on the ink solids.

On the other hand, using only an organic solvent with a boiling point of 200° C. or higher will result in a decrease in drying properties after printing, so it is preferable to use an organic solvent with a boiling point of less than 200° C. in combination.
The organic solvent having a boiling point of less than 200° C. is not particularly limited, and examples thereof include aromatic hydrocarbon organic solvents such as toluene, xylene, Solvesso #100, Solvesso #150, etc.; aliphatic hydrocarbon organic solvents such as hexane, methylcyclohexane, heptane, octane, decane, etc.; and various ester-based organic solvents such as methyl acetate, ethyl acetate, isopropyl acetate, normal propyl acetate, butyl acetate, amyl acetate, ethyl formate, butyl propionate, etc. Examples of water-miscible organic solvents include various organic solvents such as alcohols, such as methanol, ethanol, propanol, butanol, and isopropyl alcohol, ketones, such as acetone, methyl ethyl ketone, and cyclohexanone, and glycol ethers, such as ethylene glycol (mono, di) methyl ether, ethylene glycol (mono, di) ethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono, di) methyl ether, diethylene glycol (mono, di) ethyl ether, propylene glycol (mono, di) methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol (mono, di) methyl ether. These can be used alone or in combination of two or more.

Of these, from the standpoint of both work hygiene during printing and the harmfulness of packaging materials, it is more preferable to use ethyl acetate, propyl acetate, isopropanol, normal propanol, etc., and not to use aromatic solvents such as toluene or ketone solvents such as methyl ethyl ketone.
The organic solvent having a boiling point of 200° C. or less is used to adjust the ink viscosity to a desired level during printing, and there is no particular restriction on the amount added.

(Coloring Agent)
The liquid printing ink of the present invention preferably contains a colorant. The colorant is preferably a pigment, and examples thereof include inorganic pigments and organic pigments used in general inks, paints, and recording materials. Examples of organic pigments include soluble azo-based, insoluble azo-based, azo-based, phthalocyanine-based, halogenated phthalocyanine-based, anthraquinone-based, anthanthrone-based, dianthraquinonyl-based, anthrapyrimidine-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine azo-based, flavanthrone-based, diketopyrrolopyrrole-based, isoindoline-based, indanthrone-based, and carbon black-based pigments. In addition, examples of the pigments include carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, chromophthal yellow, chromophthal red, phthalocyanine blue, phthalocyanine green, dioxazine violet, quinacridone magenta, quinacridone red, indanthrone blue, pyrimidine yellow, thioindigo bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, and daylight fluorescent pigments. In addition, both non-acid-treated pigments and acid-treated pigments can be used. Specific examples of preferred organic pigments are listed below.

Examples of black pigments include C.I. Pigment Black 1, C.I. Pigment Black 6, C.I. Pigment Black 7, C.I. Pigment Black 9, and C.I. Pigment Black 20.

Examples of indigo pigments include C.I. Pigment Blue 15, C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:5, C.I. Pigment Blue 15:6, C.I. Pigment Blue 16, C.I. Pigment Blue 17:1, C.I. Pigment Blue 22, C.I. Pigment Blue 24:1, C.I. Pigment Blue 25, C.I. Pigment Blue 26, C.I. Pigment Blue 60, C.I. Pigment Blue 61, C.I. Pigment Blue 62, C.I. Pigment Blue 63, C.I. Pigment Blue 64, C.I. Pigment Blue 75, C.I. Pigment Blue 79, C.I. Pigment Blue 80, etc.

Examples of green pigments include C.I. Pigment Green 1, C.I. Pigment Green 4, C.I. Pigment Green 7, C.I. Pigment Green 8, C.I. Pigment Green 10, and C.I. Pigment Green 36.

Examples of red pigments include C.I. Pigment Red 1, C.I. Pigment Red 2, C.I. Pigment Red 3, C.I. Pigment Red 4, C.I. Pigment Red 5, C.I. Pigment Red 6, C.I. Pigment Red 7, C.I. Pigment Red 8, C.I. Pigment Red 9, C.I. Pigment Red 10, C.I. Pigment Red 11, C.I. Pigment Red 12, C.I. Pigment Red 15, C.I. Pigment Red 16, C.I. Pigment Red 17, C.I. Pigment Red 18, C.I. Pigment Red 19, C.I. Pigment Red 20, C.I. Pigment Red 21, C.I. Pigment Red 22, C.I. Pigment Red 23, C.I. Pigment Red 31, C.I. Pigment Red 32, C.I. Pigment Red 38, C.I. Pigment Red 41, C.I. Pigment Red 43, C.I. Pigment Red 46, C.I. Pigment Red 48, C.I. Pigment Red 48:1, C.I. Pigment Red 48:2, C.I. Pigment Red 48:3, C.I. Pigment Red 48:4, C.I. Pigment Red 48:5, C.I. Pigment Red 48:6, C.I. Pigment Red 49, C.I. Pigment Red 49:1, C.I. C.I. Pigment Red 49:2, C.I. Pigment Red 49:3, C.I. Pigment Red 52, C.I. Pigment Red 52:1, C.I. Pigment Red 52:2, C.I. Pigment Red 53, C.I. Pigment Red 53:1, C.I. Pigment Red 53:2, C.I. Pigment Red 53:3, C.I. Pigment Red 54, C.I. Pigment Red 57, C.I. Pigment Red 57:1, C.I. Pigment Red 58, C.I. Pigment Red 58:1, C.I. Pigment Red 58:2, C.I. Pigment Red 58:3, C.I. Pigment Red 58:4, C.I. C.I. Pigment Red 60:1, C.I. Pigment Red 63, C.I. Pigment Red 63:1, C.I. Pigment Red 63:2, C.I. Pigment Red 63:3, C.I. Pigment Red 64:1, C.I. Pigment Red 68, C.I. Pigment Red 68, C.I. Pigment Red 81:1, C.I. Pigment Red 83, C.I. Pigment Red 88, C.I. Pigment Red 89, C.I. Pigment Red 95, C.I. Pigment Red 112, C.I. Pigment Red 114, C.I. Pigment Red 119, C.I. Pigment Red 122, C.I. Pigment Red 123, C.I. Pigment Red 136, C.I. Pigment Red 144, C.I. Pigment Red 146, C.I. Pigment Red 147, C.I. Pigment Red 149, C.I. Pigment Red 150, C.I. Pigment Red 164, C.I. Pigment Red 166, C.I. Pigment Red 168, C.I. Pigment Red 169, C.I. Pigment Red 170, C.I. Pigment Red 171, C.I. Pigment Red 172, C.I. Pigment Red 175, C.I. Pigment Red 176, C.I. Pigment Red 177, C.I. Pigment Red 178, C.I. Pigment Red 179, C.I. Pigment Red 180, C.I. Pigment Red 181, C.I. Pigment Red 182, C.I. Pigment Red 183, C.I. Pigment Red 184, C.I. Pigment Red 185, C.I. Pigment Red 187, C.I. Pigment Red 188, C.I. Pigment Red 190, C.I. Pigment Red 192, C.I. Pigment Red 193, C.I. Pigment Red 194, C.I. Pigment Red 200, C.I. Pigment Red 202, C.I. Pigment Red 206, C.I. Pigment Red 207, C.I. Pigment Red 208, C.I. Pigment Red 209, C.I. Pigment Red 210, C.I. Pigment Red 211, C.I. Pigment Red 213, C.I. Pigment Red 214, C.I. Pigment Red 216, C.I. Pigment Red 215, C.I. Pigment Red 216, C.I. Pigment Red 220, C.I. Pigment Red 221, C.I. Pigment Red 223, C.I. Pigment Red 224, C.I. Pigment Red 226, C.I. Pigment Red 237, C.I. Pigment Red 238, C.I. Pigment Red 239, C.I. Pigment Red 240, C.I. Pigment Red 242, C.I. Pigment Red 245, C.I. Pigment Red 247, C.I. Pigment Red 248, C.I. Pigment Red 251, C.I. Pigment Red 253, C.I. Pigment Red 254, C.I. Pigment Red 255, C.I. Pigment Red 256, C.I. Pigment Red 257, C.I. Pigment Red 258, C.I. Pigment Red 260, C.I. Pigment Red 262, C.I. Pigment Red 263, C.I. Pigment Red 264, C.I. Pigment Red 266, C.I. Pigment Red 268, C.I. Pigment Red 269, C.I. Pigment Red 270, C.I. Pigment Red 271, C.I. Pigment Red 272, C.I. Pigment Red 279, etc.

Examples of purple pigments include C.I. Pigment Violet 1, C.I. Pigment Violet 2, C.I. Pigment Violet 3, C.I. Pigment Violet 3:1, C.I. Pigment Violet 3:3, C.I. Pigment Violet 5:1, C.I. Pigment Violet 13, C.I. Pigment Violet 19 (γ type, β type), C.I. Pigment Violet 23, C.I. Pigment Violet 25, C.I. Pigment Violet 27, C.I. Pigment Violet 29, C.I. Pigment Violet 31, C.I. Pigment Violet 32, C.I. Pigment Violet 36, C.I. Pigment Violet 37, C.I. Pigment Violet 38, C.I. Pigment Violet 42, C.I. Pigment Violet 50, etc.

Examples of yellow pigments include C.I. Pigment Yellow 1, C.I. Pigment Yellow 3, C.I. Pigment Yellow 12, C.I. Pigment Yellow 13, C.I. Pigment Yellow 14, Pigment Yellow 17, C.I. Pigment Yellow 24, C.I. Pigment Yellow 42, C.I. Pigment Yellow 55, C.I. Pigment Yellow 62, C.I. Pigment Yellow 65, C.I. Pigment Yellow 74, C.I. Pigment Yellow 83, C.I. Pigment Yellow 86, C.I. Pigment Yellow 93, C.I. Pigment Yellow 94, C.I. Pigment Yellow 95, C.I. Pigment Yellow 109, C.I. Pigment Yellow 110, C.I. Pigment Yellow 117, C.I. Pigment Yellow 120, Pigment Yellow 125, C.I. Pigment Yellow 128, C.I. Pigment Yellow 129, C.I. Pigment Yellow 137, C.I. Pigment, Yellow 138, C.I. Pigment Yellow 139, C.I. Pigment Yellow 147, C.I. Pigment Yellow 148, C.I. Pigment Yellow 150, C.I. Pigment Yellow 151, C.I. Pigment Yellow 153, C.I. Pigment Yellow 154, C.I. Pigment Yellow 155, C.I. Pigment Yellow 166, C.I. Pigment Yellow 168, C.I. Examples of the pigments include C.I. Pigment Yellow 174, C.I. Pigment Yellow 180, C.I. Pigment Yellow 185, and C.I. Pigment Yellow 213.

Examples of orange pigments include C.I. Pigment Orange 5, C.I. Pigment Orange 13, C.I. Pigment Orange 16, C.I. Pigment Orange 34, C.I. Pigment Orange 36, C.I. Pigment Orange 37, C.I. Pigment Orange 38, C.I. Pigment Orange 43, C.I. Pigment Orange 51, C.I. Pigment Range 55, C.I. Pigment Orange 59, C.I. Pigment Orange 61, C.I. Pigment Orange 64, C.I. Pigment Orange 71, and C.I. Pigment Orange 74.

Examples of brown pigments include C.I. Pigment Brown 23, C.I. Pigment Brown 25, and C.I. Pigment Brown 26.

Among them, preferred pigments include C.I. Pigment Black 7 as a black pigment,
As indigo pigments, C.I. Pigment Blue 15, C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:6,
As a green pigment, C.I. Pigment Green 7,
Red pigments include C.I. Pigment Red 57:1, C.I. Pigment Red 48:1, C.I. Pigment Red 48:2, C.I. Pigment Red 48:3, C.I. Pigment Red 146, C.I. Pigment Red 242, C.I. Pigment Red 185, C.I. Pigment Red 122, C.I. Pigment Red 178, C.I. Pigment Red 149, C.I. Pigment Red 144, C.I. Pigment Red 166,
As purple pigments, C.I. Pigment Violet 23, C.I. Pigment Violet 37,
Yellow pigments include C.I. Pigment Yellow 83, C.I. Pigment Yellow 14, C.I. Pigment Yellow 180, C.I. Pigment Yellow 139,
Orange pigments include C.I. Pigment Orange 38, C.I. Pigment Orange 13, C.I. Pigment Orange 34, C.I. Pigment Orange 64,
It is preferable to use at least one or two or more selected from these groups.

Inorganic pigments include white inorganic pigments such as titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, lithopone, antimony white, and gypsum. Among inorganic pigments, the use of titanium oxide is particularly preferred. Titanium oxide exhibits a white color and is preferred in terms of coloring power, hiding power, chemical resistance, and weather resistance, and from the standpoint of printing performance, the titanium oxide is preferably treated with silica and/or alumina.

Examples of inorganic pigments other than white include aluminum particles, mica, bronze powder, chrome vermilion, yellow lead, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, and zircon. Aluminum is in powder or paste form, but it is preferable to use it in paste form from the standpoint of ease of handling and safety, and whether leafing or non-leafing is used is selected appropriately from the standpoint of brightness and concentration.

The pigment is preferably contained in an amount sufficient to ensure the concentration and coloring power of the liquid printing ink, i.e., 1 to 60% by mass of the total mass of the ink, or 10 to 90% by mass in terms of the weight ratio of solids in the ink. These pigments can be used alone or in combination of two or more kinds.

The liquid printing ink of the present invention may further contain, if necessary, an extender pigment, a leveling agent, a defoaming agent, a plasticizer, an infrared absorbing agent, an ultraviolet absorbing agent, an aromatic agent, a flame retardant, and the like.
For example, when an appropriate amount of silica is added as the extender pigment, the abrasion resistance tends to be further improved.

The liquid printing ink of the present invention can be produced by dissolving and/or dispersing a binder resin, a pigment, etc., in an organic solvent. Specifically, a pigment dispersion is produced in which a pigment is dispersed in an organic solvent using a binder resin, and the resulting pigment dispersion can be mixed with other compounds, etc., as necessary, to produce the ink.

The particle size distribution of the pigment in the pigment dispersion can be adjusted by appropriately adjusting the size of the grinding media of the dispersing machine, the packing rate of the grinding media, the dispersion treatment time, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, etc. As the dispersing machine, for example, a commonly used roller mill, ball mill, pebble mill, attritor, sand mill, etc. can be used.
When air bubbles or unexpectedly large particles are contained in the ink, they degrade the quality of the printed matter, so it is preferable to remove them by filtration, etc. As the filter, a conventionally known filter can be used.

The viscosity of the ink produced by the above method is preferably in the range of 10 mPa·s or more from the viewpoint of preventing sedimentation of the pigment and adequately dispersing it, and 1000 mPa·s or less from the viewpoint of workability during ink production and printing. The above viscosity is measured at 25° C. using a B-type viscometer manufactured by Tokimec Co., Ltd.
The viscosity of the ink can be adjusted by appropriately selecting the types and amounts of raw materials used, binder resins, pigments, organic solvents, etc. The viscosity of the ink can also be adjusted by adjusting the particle size and particle size distribution of the pigments in the ink.

(Printed matter and laminates)
The liquid printing ink of the present invention is printed on any substrate to obtain a printed matter. The substrate used in the present invention is not particularly limited, and may be a paper or plastic substrate normally used in the gravure/flexographic printing field, or a soft packaging substrate used in the food packaging field, but is particularly excellent in printability for paper. For example, the paper may be high-quality paper, kraft paper, pure white roll paper, glassine paper, parchment paper, Manila cardboard, white cardboard, coated paper, art paper, imitation paper, thin paper, thick paper, polyethylene coated paper, various synthetic papers, acid-resistant paper, etc., used for printing on packaging materials and packages for cosmetics, beverages, medicines, toys, equipment, etc.

Printing on paper can be done by the well-known gravure printing or flexographic printing. The thickness of the printing ink formed by the gravure printing or flexographic printing method is, for example, 10 μm or less, preferably 5 μm or less.

A printed matter printed with the liquid printing ink of the present invention can be subjected to a corona treatment or the like as necessary, and then a resin for extrusion lamination can be extrusion laminated onto the printed surface without the use of an adhesive to obtain a laminated product.
The resin used in the extrusion lamination preferably includes at least one of polyethylene resin, polypropylene resin, mixed resin of polyethylene and polypropylene, ethylene-vinyl acetate copolymer resin, ethylene-(meth)acrylic acid copolymer resin, ethylene-methyl(meth)acrylate copolymer resin, ethylene-ethyl(meth)acrylate copolymer resin, ethylene-vinyl alcohol copolymer resin, polyamide resin, polyvinyl alcohol resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, polyester acrylate resin, epoxy acrylate resin, urethane acrylate resin, polyether acrylate resin, diallyl phthalate resin, nitrocellulose resin, polyurethane resin, polyester resin, acrylic resin, chlorinated polyolefin resin, vinyl chloride-vinyl acetate copolymer, and rosin-based resin. The resin may be the same as or different from the substrate. The resin is preferably polyethylene resin. The thickness of the laminate is not particularly limited, but is generally 1 to 100 μm.

It is also possible to use adhesives, and similar laminated products can be obtained by using the usual extrusion lamination method in which polyethylene resin is laminated onto the printed surface via various anchor coating agents such as imine-based, isocyanate-based, polybutadiene-based, and titanium-based.

The laminate of the present invention can be used for the aforementioned paper cup containers for food, food, confectionery, household goods, pet food, or packaging materials for industrial products, as well as for agricultural, civil engineering, fishing, automobile interior and exterior use, marine, daily necessities, building interior and exterior use, housing equipment, medical care and medical equipment, pharmaceuticals, home appliances, furniture, stationery and office supplies, sales promotion, commercial use, electrical and electronic industry, and industrial materials.

The present invention will be described more specifically with reference to examples. In the following, "parts" and "%" are all based on mass.
In the present invention, the weight average molecular weight (converted into polystyrene) was measured by gel permeation chromatography (GPC) using an HLC8220 system manufactured by Tosoh Corporation under the following conditions.
Separation column: Four TSKgel GMHHR-N columns manufactured by Tosoh Corporation were used. Column temperature: 40° C. Mobile phase: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow rate: 1.0 ml/min. Sample concentration: 0.4% by mass. Sample injection amount: 100 microliters. Detector: differential refractometer.
The acid value was determined in accordance with JIS K0070, and the softening point was determined in accordance with JIS K6863.

Example 1
Vinyl chloride-vinyl isobutyl ether copolymer resin (weight average molecular weight 100.16, chlorine % of vinyl isobutyl ether polymer: 4) 2 parts, Solvine A (manufactured by Nissin Chemical Industry Co., Ltd.) as vinyl chloride-vinyl acetate copolymer resin 4 parts, rosin resin-1 (acid value 39 mgKOH/g or less, softening point 130 to 140°C) 3 parts, acrylic resin (styrene-acrylic resin, weight average molecular weight 53,300, acid value 40.5 mgKOH/g) 11 parts, methacrylic acid ester copolymer (acid value 4 or more A total of 100 parts of red liquid printing ink was prepared by adding 1 part of red azo pigment (C.I. Pigment Red 146, manufactured by DIC Corporation) (glass transition temperature 47°C), 8 parts of a mixed solvent of methyl ethyl ketone, ethyl acetate, isopropyl alcohol, ethanol and 1-methoxypropanol in a mass ratio of 42/29/14/10/5 as other organic solvents and kneading the mixture. Then, 2 parts of glycerin (boiling point 290°C) as an organic solvent with a boiling point of 200°C or higher, 0.5 parts of wax composed of an oxide of low molecular weight ethylene propylene copolymer, and 1 part of titanium tetraacetylacetonate (manufactured by Matsumoto Fine Chemical Co., Ltd.) as a chelating compound were added.

[Examples 2 to 3, Comparative Examples 1 to 10]
According to the formulations shown in Tables 1 to 3, red liquid printing inks were prepared using the same raw materials and procedures as in Example 1.
In Comparative Example 3, 3 parts of rosin resin-2 (acid value 200 mgKOH/g or less, softening point 135 to 145°C) were used in place of 3 parts of rosin resin-1 (acid value 39 mgKOH/g or less, softening point 130 to 140°C) in Example 1, and in Comparative Example 4, 3 parts of rosin resin-3 (acid value 25 mgKOH/g or less, softening point 165°C or higher) were used.

[Method for producing printed matter and laminated matter]
The viscosity of each liquid printing ink was adjusted to 15 seconds (liquid temperature 25°C) using a dedicated dilution solvent made by mixing methyl ethyl ketone/propyl acetate/ethyl acetate in a mass ratio of 30/30/40 with a Zahn cup #3 (manufactured by Rigo Co., Ltd.). Using a gravure proofing machine equipped with a halftone screen of 175 lines and 25μ gravure solid plate, the ink was printed on acid-resistant paper (285g/ ^m2 ) and dried at 40°C to obtain a printed matter. On the obtained printed matter, molten low-density polyethylene resin was extrusion laminated to a thickness of 20μm according to a conventional method to obtain the desired laminated product.

[Evaluation item 1: Adhesion]
Cellophane tape (manufactured by Nichiban, 18 mm width) was applied to the printed surface of the obtained print, and the tape was quickly peeled off, and the condition of the printed surface was visually evaluated.
(Evaluation Criteria)
5: Paper layer peeled off.
4: About 90% of the paper layer peeled off.
3: Approximately 80% of the paper peels off.
2: About half of the paper peeled off or the ink layers peeled off.
1: Ink delamination.

[Evaluation item 2: offset]
The printed surface of the obtained print was placed on the back surface of the base paper, and a 200 g weight was dropped from a height of 30 cm onto the test piece from the back surface of the printed surface using a DuPont impact tester, and the degree of color bleeding onto the back surface of the base paper was visually determined.
(Evaluation Criteria)
5: No ink removed 4: About 20% of the ink removed 3: About 30% of the ink removed 2: About half of the ink removed 1: More than 80% of the ink removed

[Evaluation item 3: Stability over time]
The stock solution of each liquid printing ink was stored at room temperature and in a thermostatic chamber at 40° C. for 4 weeks, and a comparison with the initial viscosity was made using a Zahn Cup #4 manufactured by Rigo Co., Ltd.
(Evaluation Criteria)
5: Viscosity over time is 1.2 times or less than the initial viscosity 4: Viscosity over time is 1.3 times or less than the initial viscosity 3: Viscosity over time is 1.7 times or less than the initial viscosity 2: Viscosity over time is 2.0 times or less than the initial viscosity 1: Viscosity over time is 3.0 times or more than the initial viscosity

[Evaluation item 4: Laminate strength]
The laminated printed matter was cut to a length of 1.5 cm, and the strength was measured using a Tensilon tensile strength tester at a peel speed of 300 mm/min and a peel angle of 90 degrees. Units: gf/15 mm width
Additionally, the peel interface after strength measurement was also visually inspected.
5: The film broke before the peeling interface peeled off (PE break)
4: Paper peeling occurred. Peel strength was 200 gf/15 mm width or more. 3: Paper peeling occurred. Peel strength was 160 gf/15 mm or more and less than 200 gf/15 mm width. 2: Paper peeling occurred. Peel strength was less than 160 gf/15 mm width. 1: Ink cohesive failure occurred. Peel strength was less than 160 gf/15 mm width.

The formulation of each red liquid printing ink, the mass percentage of each resin and titanium chelate relative to the ink solids content, and the evaluation results are shown in Tables 1 to 3. All parts other than the organic solvent are shown as parts by mass of the solids content.
The blank spaces in the table indicate that no blend was used.

In Table 3, the "PE break" in the laminate strength for Comparative Example 7 indicates that the film broke before the peel interface peeled off, making the laminate strength unmeasurable.

The above results show that the liquid printing ink of the present invention has excellent adhesion, stability over time, and resistance to offset, and the laminate strength of the laminate obtained by laminating the printed material is excellent.

Claims (5)

A liquid printing ink containing a vinyl chloride-vinyl acetate copolymer resin and an acrylic resin as a main binder resin and an organic solvent having a boiling point of less than 200°C , the liquid printing ink being characterized in that it satisfies the following:
(1) The ink contains 1 to 12 mass% vinyl chloride-vinyl isobutyl ether copolymer resin based on the total non-volatile components .
(2) The ink contains 1 to 25% by mass of a rosin-based resin having an acid value of 190 mg KOH/g or less and a softening point of 160° C. or less, based on the total nonvolatile components of the ink .
(3) The ink contains a chelating compound in an amount of 1 to 10 mass% based on the total non-volatile components .
(4) Contains a non-volatile organic solvent with a boiling point of 200°C or higher. The liquid printing ink according to claim 1, wherein the chelate compound is a titanium chelate compound. A printed matter printed with the liquid printing ink according to claim 1 or 2. A paper print produced by printing the liquid printing ink according to claim 1 or 2 on paper. A laminate in which a polyolefin layer is extrusion laminated onto the paper print according to claim 4.