Gravure or flexographic ink

Abstract

To provide a gravure or flexo ink that exhibits superior storage stability, laminate strength during lamination and heat sealing strength, and plate blocking resistance and plate clogging resistance during printing.SOLUTION: A gravure or flexo ink comprises a pigment, a polyurethane resin, a vinyl chloride copolymer resin and / or a cellulose resin, and an acidic compound, wherein the acidic compound comprises a block copolymer having a structure derived from polyether and / or polyester.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to gravure or flexographic inks that are excellent in storage stability, laminating strength and heat-sealing strength when laminated, and plate-fogging property and plate-clogging property during printing.

Background Art

[0002] In printing inks, paints, etc., by dispersing pigments in a fine state, printed matter or coated articles are given appropriate properties such as clear color tones and gloss. Also, by dispersing pigments in a stable state, the fluidity of printing inks and paints is improved, and printing suitability such as plate-fogging property and printing effects such as plate-clogging are improved. Especially in white ink, the pigment content is very high, and it can be said that maintaining a stable dispersion state is essential. Furthermore, a dispersion in a stable state is generally excellent in storage stability and laminating strength. Also, in laminating applications, since heat-sealing after lamination is also assumed, laminating inks are required to have heat resistance in addition to plate-fogging property and storage stability. However, there has never been a product that satisfies all of these characteristics, which has been a problem.

[0003] In order to solve such problems, various pigment dispersants have been developed. For example, although the pigment derivatives disclosed in Patent Document 1 and the polyesters disclosed in Patent Documents 2 and 3 show certain effects as pigment dispersants, when finer pigments are used for the purpose of obtaining higher-quality printing inks and paints, their effects were not sufficient. Furthermore, due to the increasing interest in environmental problems in recent years, the organic solvents used in printing inks and paints are changing from those mainly composed of aromatic systems such as toluene to those mainly composed of ester systems or alcohol systems, which is extremely disadvantageous for dispersing pigments. In such printing inks and paints, the effects of the above-mentioned pigment dispersants were not satisfactory.

[0004] Furthermore, Patent Document 4 discloses a pigment dispersion containing a phosphate ester containing a polyether and / or polyester, but it states that the dispersibility is improved by using a basic functional group-containing organic dye derivative in combination, and the phosphate ester containing a polyether and / or polyester alone did not show any effect.

[0005] Furthermore, Patent Document 5 discloses a white ink containing a phosphate ester having a polyalkylene ether structure, but it does not describe heat seal strength, plate coverage, or plate clogging. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Special Publication No. 41-2466 [Patent Document 2] Special Publication No. 54-34009 [Patent Document 3] Special Publication No. 63-30057 [Patent Document 4] Japanese Patent Publication No. 2003-183562 [Patent Document 5] Japanese Patent Publication No. 2021-138785 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The present invention aims to provide a gravure or flexographic ink that offers excellent storage stability, lamination strength and heat seal strength when laminated, and excellent plate coverage and plate clogging during printing. [Means for solving the problem]

[0008] In other words, the present invention relates to a gravure or flexographic ink containing a pigment, a polyurethane resin, a vinyl chloride copolymer resin and / or a cellulose resin, and an acidic compound, wherein the acidic compound includes a block copolymer having a structure derived from a polyether and / or polyester.

[0009] The present invention also relates to the above-mentioned gravure or flexographic ink, characterized in that the pigment contains titanium dioxide.

[0010] The present invention also relates to the above-mentioned gravure or flexographic ink, characterized in that the polyurethane resin contains a structure derived from a dibasic acid, and the dibasic acid contains sebacic acid.

[0011] The present invention also relates to the above-mentioned gravure or flexographic ink, characterized in that the sebacic acid content is 50% by mass or more of the total mass of dibasic acids.

[0012] The present invention also relates to the above-mentioned gravure or flexographic ink, characterized in that the polyurethane resin contains a structure derived from polyisocyanate, and the polyisocyanate includes aromatic polyisocyanate and aliphatic polyisocyanate.

[0013] The present invention also relates to the above-mentioned gravure or flexographic ink, characterized in that the content of the aromatic polyisocyanate is 50% by mass or more of the total mass of the polyisocyanate.

[0014] The present invention further relates to the above-mentioned gravure or flexographic ink, characterized in that it contains a fatty acid amide.

[0015] The present invention further relates to the above-mentioned gravure or flexographic ink, characterized in that it contains chlorinated polypropylene resin.

[0016] The present invention also relates to the gravure or flexo ink as described above, wherein the acidic compound has a phosphate group.

[0017] The present invention also relates to the gravure or flexo ink as described above, wherein the block copolymer contains a structure derived from lactone.

[0018] The present invention also relates to a printed matter having a printing layer made of the above gravure or flexo ink on a substrate 1.

[0019] The present invention also relates to a laminate having at least a substrate 1, a printing layer made of the above gravure or flexo ink, and a substrate 2 in this order.

Effects of the Invention

[0020] According to the present invention, it has been possible to provide a gravure or flexo ink excellent in storage stability, laminate strength and heat seal strength when laminated, and plate scumming property and plate clogging property during printing.

Modes for Carrying Out the Invention

[0021] Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents as long as it does not exceed the gist thereof. In addition, the "gravure or flexo ink" may be simply described as "ink", which is synonymous.

[0022] The present invention is characterized by being a gravure or flexo ink containing an acidic compound containing a pigment, a polyurethane resin, a vinyl chloride copolymer resin and / or a cellulose-based resin, and a block copolymer having a structure derived from a polyether and / or a polyester. In the present invention, the binder resin refers to the binder resin component in the gravure or flexo ink, and the polyurethane resin, the vinyl chloride copolymer resin and / or the cellulose-based resin are binder resins.

[0023] In this invention, combining an acidic compound containing a block copolymer having a structure derived from polyurethane resin, vinyl chloride copolymer resin and / or cellulose resin, polyether and / or polyester improves pigment dispersibility and storage stability. This is presumed to be because the block copolymer portion of the acidic compound is compatible with the pigment or polyurethane resin, and the acidic group portion is compatible with vinyl chloride copolymer resin and / or cellulose resin, resulting in an interaction that significantly improves the pigment dispersibility of the ink. As a result of this improved pigment dispersibility, lamination strength, heat seal strength, plate coverage, and plate clogging are improved. Furthermore, if the polyurethane resin contains a structure derived from a dibasic acid, and contains 50% or more by mass of sebacic acid in the total mass of the dibasic acid, and if the polyurethane resin contains a structure derived from a polyisocyanate, and the polyisocyanate contains both aromatic and aliphatic polyisocyanates, then the laminate strength and heat seal strength are improved. This is presumed to be due to the interaction between the hydrophobic structure derived from sebacic acid and the substrate, and the interaction between the structure derived from sebacic acid and the structure derived from isocyanate. However, this explanation is based solely on speculation and does not limit the invention in any way.

[0024] (Pigment) Examples of pigments used in the gravure or flexographic ink of the present invention include inorganic pigments and organic pigments.

[0025] Examples of the inorganic pigments mentioned above include zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, aluminum particles, mica, bronze powder, chrome vermilion, lead yellow, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, titanium dioxide, and zinc oxide, with titanium dioxide being preferred among them.

[0026] The titanium dioxide used may be of the anatase, rutile, or brookite crystal structure. Among these, rutile titanium dioxide is preferred due to its good pigment dispersibility. In the industrial production of titanium dioxide, rutile ore or ilmenite ore (FeTiO3) is used as the raw material. There are two main manufacturing methods: the chlorine method and the sulfuric acid method, and either method may be used. Furthermore, to improve printability in gravure printing, titanium oxide pigments that are surface-treated are preferable. In particular, those surface-treated with at least one metal selected from Si, Al, Zn, Zr, and their oxides are preferred.

[0027] Furthermore, the titanium dioxide pigment preferably has an oil absorption capacity of 14 to 35 ml / 100g, and more preferably 17 to 32 ml / 100g, as measured by the method specified in JIS K5101. Also, the average particle size (median particle size) measured by transmission electron microscopy is preferably 0.2 to 0.3 μm. The total content of the titanium dioxide pigment is preferably 10 to 60% by weight, and more preferably 10 to 45% by weight, per 100% by weight of the ink. Multiple types of titanium dioxide pigments may also be used in combination. Furthermore, from the viewpoint of whiteness concentration, lamination strength, and residual solvent, the mass ratio of titanium dioxide pigment to binder resin (titanium dioxide / binder resin) is preferably 2.8 to 5, more preferably 3 to 4.5, and even more preferably 3.2 to 4.

[0028] Examples of organic pigments mentioned above include, but are not limited to, soluble azo pigments, insoluble azo pigments, azo pigments, phthalocyanine pigments, halogenated phthalocyanine pigments, anthraquinone pigments, anthancerone pigments, dianthaquinonyl pigments, anthrapyrimidine pigments, perylene pigments (perylene red, perinone orange), perinone pigments, quinacridone pigments (quinacridone magenta, quinacridone red), thioindigo pigments (thioindigo bordeaux, thioindigo magenta), dioxazine pigments, isoindolinone pigments, quinophthalone pigments, azomethine azo pigments, flavanthrone pigments, diketopyrrolopyrrole pigments, isoindoline pigments, indanthrone pigments, carbon black pigments, and aniline black pigments. Examples of commercially available products 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.

[0029] (Polyurethane resin) In this invention, the polyurethane resin functions as a binder resin, and its weight-average molecular weight is preferably 10,000 to 100,000. More preferably, it is 30,000 to 80,000. When the weight-average molecular weight is within the range of 10,000 to 100,000, the laminate strength tends to improve. Furthermore, the polyurethane resin is preferably contained in an amount of 1 to 25% by mass, and more preferably in an amount of 3 to 20% by mass, relative to the total mass of the ink.

[0030] The polyurethane resin in the present invention is preferably a polyurethane resin obtained by a condensation reaction between a polyol and a polyisocyanate, or a polyurethane resin (polyurethane urea resin) obtained by a reaction (called chain extension) between a urethane prepolymer having isocyanate groups at the terminals, which is a condensation product of a polyol and a polyisocyanate, and a polyamine. The polyol preferably includes a high molecular weight polyol, and more preferably the high molecular weight polyol has a weight-average molecular weight of 400 to 10000.

[0031] Examples of polyols include polyester polyols, polyether polyols, polycaprolactone diols, polycarbonate polyols, polyolefin polyols, castor oil polyols, hydrogenated castor oil polyols, dimer diols, and hydrogenated dimer diols. Among these, polyester polyols are preferred. It is preferable that the total mass of the raw material polyols contain 50% by mass or more of polyester polyols, and even more preferable that it contains 70% by mass or more.

[0032] (Polyester polyol) Examples of polyester polyols include condensates obtained by the esterification reaction of polybasic acids and diols. The polybasic acid preferably includes a dibasic acid, and the dibasic acid preferably includes sebacic acid, and more preferably contains 50% by mass or more of sebacic acid in the total mass of the dibasic acid, and particularly preferably 65% ​​by mass or more. Furthermore, it is also preferable to use other dibasic acids besides sebacic acid, such as adipic acid, phthalic anhydride, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, pimelic acid, azelaic acid, suberic acid, glutaric acid, 1,4-cyclohexyldicarboxylic acid, dimer acid, and hydrogenated dimer acid. Adipic acid and succinic acid are more preferred as dibasic acids to be used in combination with sebacic acid.

[0033] Preferably, the diol includes both branched and linear diols. This results in better laminate strength in the laminate. Here, a branched diol refers to a diol in which at least one hydrogen atom of the hydrocarbon group of an alkylene glycol is substituted with a non-hydrogen atom, and a linear diol refers to a diol having two or more atoms, including alkylene glycols, dialkylene glycols, trialkylene glycols, and other diols.

[0034] Suitable examples of the above-mentioned branched diols include 2-butyl-2-ethyl-1,3-propanediol (also written as BEPG), 2-methyl-1,3-propanediol (also written as MPO), 3-methyl-1,5-pentanediol (also written as MPD), neopentyl glycol (also written as NPG), 1,2-propylene glycol (also written as PG), 2,4-diethyl-1,5-pentanediol, 1,3-butanediol, and dipropylene glycol. In particular, it is preferable that the branched diol be at least one selected from MPO, MPD, BEPG, NPG, PG, and 2,4-diethyl-1,5-pentanediol, and it is even more preferable to use NPG and / or BEPG, and it is especially preferable to use NPG.

[0035] The linear diol mentioned above is preferably an alkylene glycol, and examples of such compounds include ethylene glycol (also written as EG), diethylene glycol, 1,3-propanediol (also written as 1,3-PD), 1,4-butanediol (also written as 1,4-BD), 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,4-butynediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, and the like. Among these, linear diols with 8 or fewer carbon atoms, preferably 6 or fewer carbon atoms, are preferred, such as EG, 1,3-PD, 1,4-BD, 1,5-pentanediol, 1,6-hexanediol, and 1,8-octanediol.

[0036] Diisocyanates are preferred as the polyisocyanates mentioned above, and various known aromatic, aliphatic, or alicyclic diisocyanates can be used as such compounds. For example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzylu isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropyl diisocyanate, methylene diisocyanate, 2,2,4-tri Representative examples include methylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanate-methyl)cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer isocyanates obtained by converting the carboxyl group of a dimer acid to an isocyanate group. These can be used individually or in combination of two or more. In particular, it is preferable to use aromatic isocyanates and aliphatic isocyanates in combination, with tolylene diisocyanate or 4,4'-diphenylmethane diisocyanate being preferred as the aromatic isocyanate and isophorone diisocyanate as the aliphatic isocyanate. Furthermore, it is preferable that aromatic isocyanates are present in 50% by mass or more of the total mass of polyisocyanate, more preferably 70% by mass or more, and even more preferably 80% by mass or more. The use of aromatic isocyanates improves the heat seal strength. The total mass of polyisocyanates in the total mass of polyurethane resin raw materials is preferably 0.1 to 20% by mass, more preferably 0.5 to 15% by mass, and even more preferably 1 to 10% by mass.

[0037] The polyamines mentioned above are preferably organic diamines, and examples of such diamines include ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, and dicyclohexylmethane-4,4'-diamine. 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-hydroxypyropyrethylenediamine, and di-2-hydroxypyropyrethylenediamine, can also be used. These organic diamines can be used individually or in combination of two or more, but isophoronediamine is preferred. Furthermore, polyfunctional amines with three or more amino groups, such as diethylenetriamine, iminobispropylamine (IBPA, 3,3'-diaminodipropylamine), N-(3-aminopropyl)butane-1,4-diamine (spermidine), 6,6-iminodihexylamine, 3,7-diazanonane-1,9-diamine, and N,N'-bis(3-aminopropyl)ethylenediamine, can also be used in combination with the above-mentioned organic diamines.

[0038] In the present invention, the polyurethane resin preferably has amino groups. When the polyurethane resin has amino groups, its amine value is preferably 0.5 to 15 mg KOH / g, and more preferably 1 to 13 mg KOH / g. Within this range, the lamination strength to the substrate tends to improve.

[0039] Monoamines may be used as reaction stoppers in chain extension reactions using polyamines. Examples of reaction stoppers include dialkylamines such as dibutylamine, diethylamine, and dipropylamine, as well as amines having hydroxyl groups such as monoethanolamine, diethanolamine, 2-amino-2-methyl-1-propanol, and tri(hydroxymethyl)aminomethane.

[0040] (Biomass-derived raw materials) In addition, available biomass-derived raw materials include sebacic acid, succinic acid, dimer acid, EG, PG, 1,3-PD, 1,4-BD, NPG, ethanol, pentylene glycol, 1,10-decanediol, dimer diol, isosorbide, lactic acid, 1,5-pentamethylene diisocyanate, and dimer isoanate.

[0041] (Vinyl chloride copolymer resin and / or cellulose resin) In the present invention, in addition to polyurethane resin, vinyl chloride copolymer resin and / or cellulose resin are used in combination. The content of the vinyl chloride copolymer resin and cellulose resin is preferably 0.3 to 15% by mass, more preferably 0.5 to 10% by mass, and more preferably 1 to 8% by mass, of the total mass of the ink. From the viewpoint of pigment dispersibility, the mass ratio of the polyurethane resin to the total mass of the vinyl chloride copolymer resin and cellulose resin (polyurethane resin mass: total mass of vinyl chloride copolymer resin and cellulose resin) is preferably 97:3 to 30:70, more preferably 95:5 to 50:50, and even more preferably 90:10 to 70:30. The total mass of polyurethane resin, vinyl chloride copolymer resin, and cellulose resin is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, of the total mass of the binder resin.

[0042] (Vinyl chloride copolymer resin) The vinyl chloride copolymer resin used in the present invention is not particularly limited as long as it contains structural units derived from vinyl chloride monomer and structural units derived from other monomers, and examples include vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-acrylic copolymer resin, and vinyl chloride-vinyl acetate-vinyl alcohol copolymer resin. Among these, it is preferable to use vinyl chloride-vinyl acetate copolymer resin or vinyl chloride-acrylic copolymer resin.

[0043] (Vinyl chloride-vinyl acetate copolymer resin) The vinyl chloride-vinyl acetate copolymer resin is a copolymer of vinyl chloride and vinyl acetate, and its weight-average molecular weight is preferably 5,000 to 100,000, and more preferably 20,000 to 70,000. Of the 100% by mass 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 99% by mass. In the above range, solubility in organic solvents is improved, and adhesion to the substrate, film properties, and laminate strength are also improved. Furthermore, to improve solubility in organic solvents, it is even more preferable to have hydroxyl groups derived from vinyl alcohol through saponification or copolymerization, and the hydroxyl value is preferably 20 to 200 mg KOH / g. In addition, the glass transition temperature is preferably 50°C to 90°C.

[0044] (Vinyl chloride-acrylic copolymer resin) The vinyl chloride-acrylic copolymer resin mainly consists of a copolymer resin of vinyl chloride monomer and acrylic monomer, and it is preferable that the acrylic monomer contains (meth)acrylate hydroxyalkyl ester to improve adhesion to the substrate and solubility in organic solvents. The acrylic monomer may be incorporated into the main chain of polyvinyl chloride in blocks or randomly, or it may be graft polymerized into the side chain of polyvinyl chloride. The vinyl chloride-acrylic copolymer resin preferably has a weight-average molecular weight of 10,000 to 100,000, and more preferably 30,000 to 70,000. It is also preferable that the hydroxyl value be 20 to 200 mg KOH / g and the glass transition temperature be 50°C to 90°C.

[0045] Furthermore, the structure derived from vinyl chloride monomer in the vinyl chloride-acrylic copolymer resin is preferably 70 to 95% by mass of 100% by mass of the solid content of the vinyl chloride-acrylic copolymer resin. In this case, solubility in organic solvents is improved, and adhesion to the substrate, film properties, and laminate strength are also improved.

[0046] The above acrylic monomers preferably include those having a hydroxyl group. Examples include hydroxyalkyl esters of (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, and 8-hydroxyoctyl (meth)acrylate, as well as glycol mono(meth)acrylates such as polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, and 1,4-cyclohexanedimethanol mono(meth)acrylate, caprolactone-modified (meth)acrylate, and hydroxyethylacrylamide. Among these, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 2-hydroxypropyl acrylate are more preferred because they improve solubility in solvents. These can be used individually or in combination of two or more. Other acrylic monomers may be included as needed.

[0047] (Cellulose resin) Examples of cellulose-based resins include nitrocellulose, cellulose acetate propionate, cellulose acetate butyrate, hydroxyalkylcellulose, and carboxyalkylcellulose. Examples of alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, and hexyl groups, and the alkyl group may also have substituents. Among these, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferred. The mass-average molecular weight of the cellulose resin is preferably 5,000 to 200,000, more preferably 10,000 to 10,000, and even more preferably 15,000 to 80,000. The glass transition temperature of the cellulose resin is preferably 120°C to 180°C, more preferably 130°C to 170°C. By using the aforementioned polyurethane resin and cellulose-based resin in combination, the plate coverage, plate clogging resistance, and blocking resistance are improved.

[0048] (Nitrocellulose) Nitrocellulose is preferably obtained as a nitrate ester by reacting natural cellulose with nitric acid, in which three hydroxyl groups in the six-membered ring of the anhydrous glucopyranose group in the natural cellulose are replaced with nitrate groups. Furthermore, the nitrogen content is preferably 10.5 to 12.5% ​​by mass.

[0049] In addition to polyurethane resin, vinyl chloride copolymer resin, and / or cellulose-based resin, various other resins can be used in combination with the ink of the present invention, depending on the application and substrate. Examples of resins that can be used include chlorinated polypropylene resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, polyamide resin, cellulose-based resin, nitrocellulose resin, acrylic resin, polyester resin, alkyd resin, rosin-based resin, rosin-modified maleic acid resin, terpene resin, phenol-modified terpene resin, ketone resin, cyclized rubber, chlorinated rubber, polybutyral, petroleum resin, and modified resins thereof. Among these, chlorinated polypropylene resin is preferred, as it improves lamination strength and heat seal strength. These resins can be used individually or in combination of two or more, and their content is preferably 1 to 6% by mass of the total mass of the ink.

[0050] (Acidic compounds containing block copolymers) In the present invention, the acidic compound includes a block copolymer having a structure derived from a polyether and / or polyester. When the structure derived from the polyether is denoted as A and the structure derived from the polyester is denoted as B, it is preferable that the structure takes the form of AB, ABA, or BAB.

[0051] In the present invention, examples of monomers used for structure formation derived from polyethers include polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether, polytetramethylene glycol monomethyl ether, and polybutylene glycol monomethyl ether. Among these, polyethylene glycol monomethyl ether and polypropylene glycol monomethyl ether are preferred.

[0052] Monomers used for structure formation derived from polyester include polymers of propiolactone, valerolactone, caprolactone, or mixtures thereof, or polymers of aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and azelaic acid, aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, or their lower alcohol esters, with ethylene glycol, 1,3-propylene glycol, 1,4-butylene glycol, 1,6-hexane glycol, diethylene glycol, neopentyl glycol, or ethylene oxide adducts of bisphenol A, or mixtures thereof. Among these, valerolactone and caprolactone are preferred, and ε-caprolactone and ε-valerolactone are particularly preferred.

[0053] In the present invention, examples of block copolymers having a structure derived from polyether include those using polyethylene glycol monomethyl ether and polypropylene glycol monomethyl ether, those using polyethylene glycol monomethyl ether and polytetramethylene glycol monomethyl ether, and those using polyethylene glycol monomethyl ether and polybutylene glycol monomethyl ether. Examples of block copolymers having structures derived from polyethers and polyesters include those using polyethylene glycol monomethyl ether and ε-caprolactone, those using polypropylene glycol monomethyl ether and ε-caprolactone, those using polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether and ε-caprolactone, those using polyethylene glycol monomethyl ether and ε-valerolactone, those using polypropylene glycol monomethyl ether and ε-valerolactone, those using polyethylene glycol monomethyl ether, polypropylene glycol monomethyl ether and ε-valerolactone, and those using polyethylene glycol monomethyl ether, ε-caprolactone and ε-valerolactone.

[0054] In the present invention, examples of acidic groups in an acidic compound include phosphate groups, carboxyl groups, and sulfo groups, with phosphate groups being preferred.

[0055] From the viewpoint of pigment dispersibility, the content of the acidic compound is preferably 0.01 to 3% by mass, and more preferably 0.1 to 1% by mass, in the ink solids of the present invention. Furthermore, from the viewpoint of pigment dispersibility, the mass ratio of the acidic compound to the pigment (acidic compound:pigment) is preferably 0.1:99.9 to 1:99, and more preferably 0.1:99.9 to 0.5:99.5.

[0056] (Fatty acid amide) The fatty acid amides are not particularly limited as long as they are those commonly used in this field. Although the fatty acid amides are dissolved or dispersed in the ink, they are thought to orient themselves on the surface of the printed film after ink printing, improving the resistance to blocking against substrates that overlap on the printing roll. Furthermore, during this process, some of the fatty acid amides bind to the block copolymer portion of the acidic compound and / or the sebaciate portion of the sebaciate-based polyester polyol in the urethane resin, improving pigment dispersibility and thus enhancing storage stability. As a result, substrate adhesion is improved, and lamination strength and heat seal strength are expected to increase. The fatty acid amide content in the ink of the present invention is preferably 0.02 to 2% by mass, more preferably 0.04 to 1.7% by mass, and more preferably 0.1 to 1.5% by mass, relative to the ink solids.

[0057] Examples of fatty acid amides include bisamides, monoamides, substituted amides, methylolamides, and esteramides. It is preferable that at least one selected from the group consisting of bisamides, monoamides, and substituted amides is used to improve blocking resistance.

[0058] <Monoamide> Monoamides are represented by the following general formula (1). General formula (1) R1-CONH2 (In the formula, R1 represents the residue obtained by removing the COOH group from a fatty acid.) Examples of monoamides include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, and erucic acid amide.

[0059] <Substituted amides> Substitutive amides are represented by the following general formula (2). General formula (2) R2-CONH-R3 (In the formula, R2 and R3 represent residues obtained by removing the COOH group from a fatty acid, and may be the same or different.) Examples of substituted amides include N-oleyl palmitate amide, N-stearyl stearate amide, N-stearyl oleate amide, N-oleyl stearate amide, and N-stearyl erucate amide.

[0060] <Bisamide> Bisamides are represented by the following general formula (3) or general formula (4). General formula (3) R4-CONH-R5-HNCO-R6 General formula (4) R7-NHCO-R8-CONH-R9 (In the formula, R4, R6, R7, and R9 represent residues obtained by removing the COOH group from a fatty acid, and may be the same or different, while R5 and R8 represent alkylene or arylene groups having 1 to 10 carbon atoms.) Examples of bisamides include methylenebisstearate, ethylenebiscaprate, ethylenebislaurate, ethylenebisstearate, ethylenebishydroxystearate, ethylenebisbehenamide, hexamethylenebisstearate, hexamethylenebisbehenamide, hexamethylenehydroxystearate, ethylenebisoleamide, ethylenebiserucamide, hexamethylenebisoleamide, N,N'-distearyladipamide, N,N'-distearylsebacinamide, N,N'-dioleyladipamide, and N,N'-dioleylsebacinamide.

[0061] Furthermore, the allerene group is preferably at least one selected from phenylene group, toluene group, and m-xylylene group.

[0062] The melting point of fatty acid amides is preferably 50°C to 150°C. Examples of suitable monoamides include lauric acid amide (melting point 87°C), palmitic acid amide (melting point 100°C), stearic acid amide (melting point 101°C), behenic acid amide (melting point 110°C), hydroxystearate amide (melting point 107°C), oleic acid amide (melting point 75°C), and erucic acid amide (melting point 81°C). Examples of substituted amides include N-oleyl palmitamide (melting point 68°C), N-stearyl stearate amide (melting point 95°C), N-stearyl oleamide (melting point 67°C), N-oleyl stearate amide (melting point 74°C), and N-stearyl erucamide (melting point 69°C). Examples of bisamides include methylenebisstearate (melting point 142°C), ethylenebisstearate (melting point 145°C), ethylenebishydroxystearate (melting point 145°C), ethylenebisbehenamide (melting point 142°C), hexamethylenebisstearate (melting point 140°C), hexamethylenebisbehenamide (melting point 142°C), hexamethylenehydroxystearate (melting point 135°C), and ethylenebisoleamide (melting point 119°C). Examples include ethylenebiserucamide (melting point 120°C), hexamethylenebisoleamide (melting point 110°C), N,N'-distearyl adipic acid amide (melting point 141°C), N,N'-distearyl sebacinamide (melting point 136°C), N,N'-dioleyl adipic acid amide (melting point 118°C), and N,N'-dioleyl sebacinamide (melting point 113°C). Among the above, those with a weight-average molecular weight of 200 to 800 are preferred in order to maintain lamination strength. More preferably, it is 250 to 700.

[0063] Furthermore, the fatty acids constituting the fatty acid amide are preferably saturated fatty acids having 12 to 20 carbon atoms and / or unsaturated fatty acids having 16 to 25 carbon atoms, and more preferably saturated fatty acids having 16 to 18 carbon atoms and / or unsaturated fatty acids having 18 to 22 carbon atoms. Particularly preferred saturated fatty acids are lauric acid, palmitic acid, stearic acid, behenic acid, and hydroxystearic acid, and particularly preferred unsaturated fatty acids are oleic acid and erucic acid. The most preferred fatty acid amide is one consisting of at least one fatty acid selected from the group consisting of palmitic acid, stearic acid, behenic acid, hydroxystearic acid, oleic acid, and erucic acid.

[0064] (Organic solvents) The ink of the present invention preferably contains an organic solvent as a liquid medium. The organic solvent used is preferably a mixed solvent, and any known organic solvents can be used, such as aromatic organic solvents like toluene and xylene, ketone organic solvents like methyl ethyl ketone and methyl isobutyl ketone, ester organic solvents like ethyl acetate, n-propyl acetate, isopropyl acetate, isobutyl acetate, methanol, ethanol, n-propanol, isopropanol, and n-butanol. Among these, organic solvents that do not contain aromatic organic solvents such as toluene and xylene (non-toluene organic solvents) are more preferred. Even more preferably, the organic solvent does not contain aromatic organic solvents and / or ketone organic solvents such as methyl ethyl ketone (hereinafter also referred to as MEK), and it is preferable that the organic solvent contains an ester organic solvent as a main component (50% by mass or more of the total mass of the organic solvent). A mixture containing both an ester organic solvent and an alcohol organic solvent is particularly preferred.

[0065] (Other additives) The ink of the present invention may also optionally contain additives such as leveling agents, defoaming agents, waxes, silane coupling agents, plasticizers, light stabilizers, silica particles, infrared absorbers, ultraviolet absorbers, fragrances, flame retardants, and curing agents.

[0066] (Ink manufacturing method) The ink of the present invention can be manufactured by, for example, pre-mixing titanium dioxide, a binder resin containing polyurethane resin, and an organic solvent using a stirring mixer, then dispersing the mixture with a pigment using a disperser such as a bead mill, and finally adding and mixing the binder resin, various additives, and organic solvents to the resulting dispersion. Commonly used dispersers such as roller mills, ball mills, pebble mills, attritors, and sand mills can be used. The particle size distribution of the pigment in the pigment dispersion can be adjusted by appropriately adjusting the size of the disperser's grinding media, the packing rate of the grinding media, the dispersion processing time, the discharge speed of the pigment dispersion, and the viscosity of the pigment dispersion.

[0067] The viscosity of the ink of the present invention is preferably in the range of 10 mPa·s or more at 25°C from the viewpoint of preventing pigment sedimentation and ensuring appropriate dispersion, and 1000 mPa·s or less from the viewpoint of workability during ink manufacturing and printing. A viscosity of 20 to 500 mPa·s is even more preferable. The above viscosity can be the viscosity value measured at 25°C using a Tokimec Type B viscometer.

[0068] (Hardening agent) The ink of the present invention is also preferably used as a two-component ink by adding a curing agent to improve the laminate strength. Preferably, polyisocyanates are used as curing agents. For example, tolylene diisocyanate (hereinafter also referred to as TDI), diphenylmethane diisocyanate (hereinafter also referred to as MDI), hexamethylene diisocyanate (hereinafter also referred to as HDI), or their respective adduct-type polyisocyanates (adduct form), biuret-type polyisocyanate (biuret form), isocyanurate-type polyisocyanate (isocyanurate form), etc., can be suitably used. For example, adduct forms obtained from the reaction of 1 mole of trimethylolpropane and 3 moles of HDI, biuret forms obtained from the reaction of 1 mole of water and 3 moles of HDI, and isocyanurate forms obtained from the cyclic trimerization reaction of HDI are suitable examples. When used as a two-component type, the amount of polyisocyanate-based curing agent added is preferably 0.5 to 10% by mass, and preferably 0.5 to 5% by mass, relative to the total amount of the ink of the present invention.

[0069] (Gravure or flexographic ink printing) The inks in this invention are suitable for printing using gravure printing or flexographic printing methods. In gravure printing, the inks are diluted with a diluent solvent to a viscosity and concentration suitable for printing, and supplied to each printing unit either alone or in mixtures.

[0070] (Gravure printing) When using the ink of the present invention for gravure printing, a gravure plate is used. In this invention, the gravure plate is a cylindrical metal plate, and recesses are created in each color by engraving, etching, or laser. There are no restrictions on the use of engraving or laser, and they can be arbitrarily set according to the pattern. Line screens of 100 to 300 lines / inch are used as appropriate, and higher line screens allow for higher-resolution printing. (Gravure printing machine) A printing press equipped with the above-mentioned gravure plates can be suitably used. Typically, a printing unit is installed for each color, and each unit is equipped with a doctor blade that scrapes off ink as the gravure plate rotates. The substrate passes through each printing unit, is intaglio printed, and then becomes a film winding. Depending on the case, a fussier roll can be used for the gravure plate. In addition, each unit is equipped with a drying oven, and the printed substrate is dried by passing it through the oven. The drying temperature is usually around 40 to 60°C.

[0071] (Flexographic printing) In this invention, the plates used for flexographic printing include photosensitive resin plates that utilize ultraviolet curing by a UV light source, or elastomer material plates that use a direct laser engraving method. Regardless of the method of forming the image portion of the flexographic plate, a screening screen count of 75 lpi or higher is used. Any type of sleeve or cushioning tape can be used to attach the plate. (Flexographic printing press) Flexographic printing presses include CI-type multi-color flexographic printing presses and unit-type multi-color flexographic printing presses, and ink supply methods include chamber systems and two-roll systems.

[0072] (base material) The ink of the present invention is printed on a substrate 1 to form a printed material. Alternatively, it is preferable to form a laminate having the substrate 1, a printed layer made of the ink of the present invention, and a substrate 2 in that order, by the method described later. The substrate 1 can be polyethylene and polypropylene or other polyolefin substrates, polycarbonate substrates, polyester substrates (such as polyethylene terephthalate and polylactic acid), polystyrene substrates, polystyrene-based substrates such as AS resin or ABS resin, polyamide substrates, polyvinyl chloride substrates, polyvinylidene chloride substrates, cellophane substrates, paper substrates or aluminum foil substrates, or a film or sheet made of a composite material thereof. Among these, polyester substrates and polyamide substrates, which have high glass transition temperatures, are preferably used.

[0073] The above-mentioned substrate 1 may have a metal oxide or the like vapor-deposited coating applied to its surface and / or a coating applied with polyvinyl alcohol, for example, GL-AE manufactured by Toppan Printing Co., Ltd., which has aluminum oxide vapor-deposited onto the substrate surface, and IB-PET-PXB manufactured by Dai Nippon Printing Co., Ltd. Furthermore, substrates treated with additives such as antistatic agents and UV inhibitors as needed, or substrates whose surfaces have been corona-treated or low-temperature plasma-treated, can also be used.

[0074] Substrate 2 can be the same as that of substrate 1, and may be the same or different. It is preferable that substrate 2 is a thermoplastic substrate (sometimes referred to as a sealant), and unstretched polyethylene substrates, unstretched polypropylene substrates, unstretched polyester substrates, etc., are preferred.

[0075] (Laminated structure) The laminate of the present invention is obtained by providing an adhesive layer on the printed layer of a printed material printed with gravure or flexographic ink, and bonding (laminating) it with a substrate 2. Typical examples of lamination processes include extrusion lamination, dry lamination, and non-solvent lamination. Extrusion lamination is a method of laminating by applying an anchor coating agent to the printed layer of a printed material and extruding molten polyethylene resin, molten polypropylene resin, etc., into it, while simultaneously bonding it with the substrate. Dry lamination and non-solvent lamination are methods of laminating by applying and drying an adhesive on the printed layer of a printed material and then heat-pressing it with a sealant. The difference between dry lamination and non-solvent lamination is whether or not they contain organic solvents or other volatile media.

[0076] (adhesive layer) The adhesive layer consists of a composition capable of bonding the ink and the substrate, and examples include a layer formed from molten polyethylene resin, molten polypropylene resin, a urethane adhesive, an acrylic adhesive, and an anchor coat layer. For example, it can be obtained by applying and drying a urethane adhesive. As the urethane adhesive, a two-component adhesive consisting of a mixture of a polyol and an isocyanate curing agent is preferred, and examples of polyols include polyester-based and polyether-based types. Specifically, examples include TM-250HV / CAT-RT86L-60, TM-550 / CAT-RT37, and TM-314 / CAT-14B manufactured by Toyo Morton Co., Ltd. [Examples]

[0077] The present invention will be described in detail below with reference to examples, but the following embodiments are only a few examples of the present invention, and the present invention is not limited to these embodiments. In the present invention, parts and % refer to parts by mass and mass %, respectively, unless otherwise noted.

[0078] <Method for measuring amine value> The amine value was determined according to the following method in accordance with JIS K0070, using the equivalent amount of hydrochloric acid and the same amount of potassium hydroxide in milligrams required to neutralize the amino groups contained in 1 g of resin. 0.5 to 2 g of the sample was accurately weighed (sample solid content: Sg). 50 mL of a methanol / methyl ethyl ketone = 60 / 40 (mass ratio) mixed solution was added to the accurately weighed sample and dissolved. Bromophenol blue was added to the resulting solution as an indicator, and the solution was titrated with 0.2 mol / L ethanolic hydrochloric acid solution (titer: f). The endpoint was defined as the point where the color of the solution changed from green to yellow, and the amine value was determined using the titration volume (A mL) at this point, according to the following formula (Equation 1). (Equation 1) Amine value = (A × f × 0.2 × 56.108) / S [mgKOH / g]

[0079] <Method for measuring number-average molecular weight (Mn) and mass-average molecular weight (Mw)> Number-average molecular weight (Mn) and mass-average molecular weight (Mw) were measured using the Showa Denko GPC (gel permeation chromatography) system "Shodex GPC System-21". GPC is a liquid chromatography method that separates and quantifies substances dissolved in a solvent based on the difference in their molecular size. Tetrohydrofuran was used as the solvent, and the molecular weight was determined in terms of polystyrene equivalents.

[0080] <Method for measuring hydroxyl value> The method was determined according to the method described in JIS K0070.

[0081] <Method for measuring acid value> The method was determined according to the method described in JIS K0070.

[0082] <Glass transition temperature> The glass transition temperature was determined from the peak value of the principal variance of the loss tangent (tanδ) obtained from dynamic viscoelastic temperature dispersion measurements using a viscoelastic spectrometer DVA-200 (manufactured by IT Measurement Control Co., Ltd.), measured at a frequency of 10 Hz, a heating rate of 10 °C / min, and a temperature range of -70 to 200 °C.

[0083] <Lamination Strength> For the laminate, the printed portion was cut to a width of 15 mm, and after separating the ink side from the substrate side, the peel strength (laminate strength) was measured using an Intesco 201 universal tensile tester. Peeling mode: 90° peeling, tensile speed: 300 mm / min

[0084] <Heat seal strength> For the laminate, the printed portion was cut out in 15mm x 100mm sections, folded so that the two base materials overlapped, and heat-sealed under the following conditions. The unsealed ends were then fixed to a small tensile testing machine, and the peel strength (heat seal strength) was evaluated under the following evaluation conditions. (Heat sealing conditions) Equipment: Heat seal tester manufactured by Tester Industries Co., Ltd. Seal width: 10mm from the folded part Heater temperature: 160℃, sealing pressure: 2kg / cm² 2 Seal time: 1 sec (Evaluation criteria) Peeling mode: 90° peeling, tensile speed: 300 mm / min

[0085] [Synthesis Example 1-1] (Synthesis of polyester polyol A1) In a round-bottom flask equipped with a stirrer, thermometer, water divider, and nitrogen gas inlet tube, 26 parts of neopentyl glycol (hereinafter also referred to as NPG), 26 parts of 1,3-propanediol (hereinafter also referred to as 1,3-PD), 8 parts of adipic acid, 40 parts of sebacic acid, and 0.002 parts of tetrabutyl titanate were charged, and esterification was carried out for 8 hours at 230°C under a nitrogen stream while removing water produced by condensation. After confirming that the acid value of the polyester was 15 or less, the vacuum was gradually increased using a vacuum pump to terminate the reaction. This yielded polyester polyol (A1) with a number average molecular weight of 2000, a hydroxyl value of 56.1 mgKOH / g, and an acid value of 0.3 mgKOH / g.

[0086] [Synthesis Examples 1-2 to 1-10] (Synthesis of polyester polyols A2-A10) Polyester polyols A2 to A10 were obtained using the same method as in Synthesis Example 1, except that the raw materials and preparation ratios listed in Table 1 were used.

[0087] [Table 1]

[0088] [Synthesis Example 2-1] (Synthesis of polyurethane resin B1) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 23.1 parts of polyester polyol A1, 0.6 parts of isophorone diisocyanate (hereinafter also referred to as IPDI), 2.3 parts of tolylene diisocyanate (hereinafter also referred to as TDI), and 7.5 parts of ethyl acetate were charged and reacted at 120°C for 6 hours under a nitrogen stream. 7.5 parts of propyl acetate were added and the mixture was cooled to obtain a solution of the terminal isocyanate prepolymer. Next, the obtained solution of the terminal isocyanate prepolymer was gradually added at room temperature to a mixture of 1.6 parts of isophorone diamine (hereinafter also abbreviated as IPDA), 0.2 parts of n-dibutylamine (hereinafter also abbreviated as DBA), 34 parts of ethyl acetate, and 23 parts of isopropyl alcohol (hereinafter also referred to as IPA). The mixture was then reacted at 50°C for 1 hour to obtain a polyurethane resin B1 solution with a solid content of 28%, a mass-average molecular weight of 65000, and an amine value of 5 mg KOH / g.

[0089] [Synthesis Examples 2-2 to 2-16] (Synthesis of polyurethane resins B2-B16) Polyurethane resins B2 to B16 were obtained using the same procedure as in Synthesis Example 2-1, except that the raw materials and preparation ratios listed in Tables 2-1 and 2-2 were used. MDI: Diphenylmethane diisocyanate

[0090] [Table 2-1]

[0091] [Table 2-2]

[0092] [Synthesis Example 3-1] (Synthesis of acidic compound C1) Under a nitrogen atmosphere, 104 parts of polyethylene glycol monomethyl ether (PEG) with a number average molecular weight of 400, 780 parts of polypropylene glycol monomethyl ether (PPG) with a number average molecular weight of 600, 10 parts of ε-caprolactone, and 1.8 parts of dibutylsus laurate were heated and stirred, and the reaction was continued at 160°C until the solid content reached 98% or more, yielding a polyether-polyester monohydroxyblock copolymer (number average molecular weight: 900). To 900 parts of the polyether-polyester monohydroxyblock copolymer, 84.5 parts of polyphosphate containing 84% by mass of phosphorus pentoxide was added, and the mixture was reacted at 80°C for 5 hours while removing water, yielding an acidic compound C1 with a number average molecular weight of 1000 (solid content 100%, acid species: phosphate group).

[0093] [Synthesis Example 3-2] (Synthesis of acidic compound C2) Under a nitrogen atmosphere, 400 parts of polyethylene glycol monomethyl ether (PEG) with a number average molecular weight of 400, 7 parts of ε-caprolactone, and 1.8 parts of dibutylsus laurate were heated and stirred, and the reaction was continued at 160°C until the solid content reached 98% or more, yielding a polyether-polyester monohydroxyblock copolymer (number average molecular weight: 810). Next, 84.5 parts of polyphosphate containing 84% by mass of phosphorus pentoxide was added to 810 parts of the polyether-polyester monohydroxyblock copolymer, and the mixture was reacted at 80°C for 5 hours while removing water, yielding an acidic compound C2 with a number average molecular weight of 950 (solid content 100%, acid species: phosphate group).

[0094] [Synthesis Example 3-3] (Synthesis of acidic compound C3) Under a nitrogen atmosphere, 1150 parts of polypropylene glycol monomethyl ether (PPG) with a number average molecular weight of 1000, 8 parts of ε-caprolactone, and 1.8 parts of dibutylsus laurate were heated and stirred, and the reaction was continued at 160°C until the solid content reached 98% or more, yielding a polyether-polyester monohydroxyblock copolymer (number average molecular weight: 1150). Next, 84.5 parts of polyphosphate containing 84% by mass of phosphorus pentoxide was added to 1150 parts of the polyether-polyester monohydroxyblock copolymer, and the mixture was reacted at 80°C for 5 hours while removing water, yielding an acidic compound C3 with a number average molecular weight of 1200 (solid content 100%, acid species: phosphate group).

[0095] [Synthesis Example 3-4] (Synthesis of acidic compound C4) Under a nitrogen atmosphere, 112 parts of polyethylene glycol monomethyl ether (PEG) with a number average molecular weight of 400, 840 parts of polypropylene glycol monomethyl ether (PPG) with a number average molecular weight of 600, 10 parts of ε-valerolactone, and 1.8 parts of dibutylsus laurate were heated and stirred, and the reaction was continued at 160°C until the solid content reached 98% or more, yielding a polyether-polyester monohydroxyblock copolymer (number average molecular weight: 1050). Next, 84.5 parts of polyphosphate containing 84% by mass of phosphorus pentoxide was added to 950 parts of the polyether-polyester monohydroxyblock copolymer, and the mixture was reacted at 80°C for 5 hours while removing water, yielding an acidic compound C4 with a number average molecular weight of 1150 (solid content 100%, acid species: phosphate group).

[0096] [Synthesis Example 3-5] (Synthesis of acidic compound C5) Under a nitrogen atmosphere, 1280 parts of polyethylene glycol monomethyl ether (PEG) with a number average molecular weight of 800, 7 parts of ε-caprolactone, 4 parts of ε-valerolactone, and 1.8 parts of dibutylsus laurate were heated and stirred, and the reaction was continued at 160°C until the solid content reached 98% or more, yielding a polyether-polyester monohydroxyblock copolymer (number average molecular weight: 1280). Next, 84.5 parts of polyphosphate containing 84% by mass of phosphorus pentoxide was added to 1280 parts of the polyether-polyester monohydroxyblock copolymer, and the mixture was reacted at 80°C for 5 hours while removing water, yielding an acidic compound C5 with a number average molecular weight of 1350 (solid content 100%, acid species: phosphate group).

[0097] [Synthesis Example 3-6] (Synthesis of acidic compound C6) Under a nitrogen atmosphere, 26 parts of polyethylene glycol monomethyl ether (PEG) with a number average molecular weight of 400 and 7 parts of pyromellitic anhydride were heated and stirred, and the reaction was continued at 160°C until the solid content reached 98% or more, yielding a polyether monohydroxy compound (number average molecular weight: 850). Next, 84.5 parts of polyphosphate containing 84% by mass of phosphorus pentoxide were added to 850 parts of the polyether monohydroxy compound, and the reaction was carried out at 80°C for 5 hours while removing water, yielding an acidic compound C6 with a number average molecular weight of 950 (100% solid content, acid species: phosphate group).

[0098] [Synthesis Example 3-7] (Synthesis of acidic compound C7) Under a nitrogen atmosphere, 410 parts of polyethylene glycol monomethyl ether (PEG) with a number average molecular weight of 2000 and 22 parts of pyromellitic anhydride were heated and stirred, and the reaction was continued at 160°C until the solid content reached 98% or more, yielding acidic compound C7 (100% solid content, acid species: carboxyl group) with a number average molecular weight of 4000.

[0099] [Example 1] (Manufacturing of Ink S1) 30 parts of titanium dioxide pigment (Teika Corporation JR806, rutile-type titanium dioxide surface-treated with silica and alumina, oil absorption 21g / 100g), 10 parts of polyurethane resin B1 solution, 6 parts of vinyl chloride-acrylic copolymer resin solution (Wacker Chemie VINNOL E15 / 40A, vinyl chloride component:acrylic component = 84:16, solids content 24%), and 16 parts of mixed solvent (ethyl acetate / IPA = 75 / 25 (mass ratio)) were stirred and mixed, then kneaded in a sand mill. After mixing, 20 parts of polyurethane resin B1 solution, 17 parts of mixed solvent (ethyl acetate / isopropyl alcohol = 75 / 25 (mass ratio)), 0.1 parts of acidic compound (C1) containing block copolymer, 0.2 parts of fatty acid amide (palmitic acid amide), and chlorinated polypropylene resin solution (Nippon Paper Industries 370M) were added. 0.3 parts of a 50% solids solution were stirred and mixed to obtain white printing ink S1 (Tables 3-1 to 3 show the total amounts of each component).

[0100] [Examples 2-28] (Manufacturing of inks S2 to S28) Inks S2 to S28 were obtained in the same manner as in Example 1, except that the raw materials and mixing ratios listed in Tables 3-1 and 3-2 were used. Phthalocyanine: LIONOLBLUEFG-73, manufactured by Toyo Color Co., Ltd. Nitrocellulose solution: Nitrocellulose solution with a nitrogen content of 11% by mass (solids content 30%, solvent: isopropyl alcohol)

[0101] [Comparative Examples 1-6] (Manufacturing of inks SS1 to SS6) Inks SS1 to SS6 were obtained in the same manner as in Example 1, except that the raw materials and mixing ratios listed in Table 3-3 were used.

[0102] [Creating printed materials using Ink S1] The viscosity of ink S1 was diluted with a mixed solvent (ethyl acetate / IPA = 75 / 25 (mass ratio)) to a viscosity of 15 seconds (at 25°C) in a Zahn cup #3 (manufactured by Rigosha). Using a gravure proofing machine equipped with a 30 μm gravure plate, the ink was printed onto the corona-treated side of a single-sided corona-treated polypropylene (OPP) film (Pyrene P2161, manufactured by Toyobo Co., Ltd.) and dried at 40-50°C to obtain a printed material using ink S1.

[0103] [Preparation of printed materials using inks S2-S28 and SS1-SS6] Printed materials using inks S2-S28 and SS1-SS6 were obtained in the same manner as the example of printed materials using ink S1 described above, except that inks S2-S28 and SS1-SS6 were used.

[0104] [Fabrication of laminates using ink S1] On the printed layer of a printed material using the above ink S1, an adhesive solution (30% non-volatile content) obtained by mixing 15 parts of adhesive (TM-250HV manufactured by Toyo Morton Co., Ltd.), 1 part of curing agent (CAT-RT86L-60 manufactured by Toyo Morton Co., Ltd.), and ethyl acetate was applied and dried to form an adhesive layer. An unstretched polypropylene (CPP) film (60 μm thick, surface corona discharge treated) was then laminated to this adhesive layer using a laminating machine and kept warm at 40°C for 4 days to produce a laminate using ink S1.

[0105] [Fabrication of laminates using inks S2-S28 and SS1-SS6] Laminates using inks S2-S28 and SS1-SS6 were prepared in the same manner as the laminate using ink S1, except that printed materials using inks S2-S28 and SS1-SS6 were used.

[0106] [evaluation] The above inks S1 to S28 (Examples), SS1 to SS6 (Comparative Examples), and laminates using them were evaluated for lamination strength, heat seal strength, plate coverage, plate clogging, and storage stability using the methods described below. The results are shown in Tables 3-1 to 3.

[0107] [Lamination strength] The above laminate was cut to a length of 150 mm and a width of 15 mm, and the laminate strength in the 90° direction was measured using a tensile testing machine. (Evaluation Criteria) 5: 1.5N / 15mm or more (excellent) 4: 1.0N / 15mm or more, less than 1.5N / 15mm (Good) 3: 0.8N / 15mm or more, less than 1.0N / 15mm (acceptable) 2: 0.5N / 15mm or more, less than 0.8N / 15mm (not acceptable) 1: Less than 0.5N / 15mm (poor) The practical level is 3 to 5.

[0108] [Heat seal strength] The above laminate was heat-sealed at 160°C with the polyethylene film side facing inward, cut into pieces 150 mm long and 15 mm wide, and the heat-seal strength in the 90° direction was measured using a tensile testing machine. (Evaluation Criteria) 5:40N / 15mm or more (excellent) 4: 30N / 15mm or more, less than 40N / 15mm (Good) 3: 20N / 15mm or more, less than 30N / 15mm (acceptable) 2: 10N / 15mm or more, less than 20N / 15mm (not acceptable) 1: Less than 10N / 15mm (poor) The practical level is 3 to 5.

[0109] [Picture overlap] The above inks S1-S28 (Examples) and SS1-SS6 (Comparative Examples) were diluted with a mixed solvent (ethyl acetate / IPA = 75 / 25 (mass ratio)) to a viscosity of 15 seconds (at 25°C) in a Zahn cup #3 (manufactured by Rigosha). This diluted ink was then visually inspected on a gravure printing press after 60 minutes of idle printing at a speed of 200 m / min. 5: No overlapping printings whatsoever (Excellent) 4: Slight plate bleed is visible at the edges of the image (Good) 3: Slight plate overlap is visible at the edges and within the image (acceptable) 2: Slight plate overlap is visible at the edges of the image, within the image area, and in non-image areas (unacceptable). 1: Significant plate overlap is visible throughout the entire plate (inferior). The practical level is 3 to 5.

[0110] [Printing density] Using the above inks S1 to S28 (Examples) and SS1 to SS6 (Comparative Examples), 100 m of each ink was printed onto OPP film at a speed of 30 m / 20 min using a gravure printing test machine (TS-1 type printing machine; manufactured by Higashitani Iron Works) with a gravure plate with a depth of 35 μm. After that, excess ink adhering to the gravure plate was lightly washed off with the above mixed solvent, and the clogging state of the cells was evaluated. 5: Less than 10% of the ink remains in the cell. 4: The remaining ink in the cell is between 10% and 30%. 3: The remaining ink in the cell is between 30% and 50%. 2: The remaining ink in the cell is between 50% and 70%. 1: More than 70% of the ink remains in the cell. The practical level is 3 to 5.

[0111] [Storage stability] As a measure of the storage stability of the ink, the state of pigment precipitate was evaluated. Specifically, inks S1-S28 (examples) and SS1-SS6 (comparative examples) were stored in sealed 70cc containers (round bottom, 3cm base diameter) at 40°C for two weeks, and the state of the precipitate was visually evaluated. 5: There is absolutely no sediment. 4. A soft sediment may form at the bottom, but it will disappear after shaking five times. 3: A soft sediment may form at the bottom, but it will disappear after shaking 10 times. 2. After shaking 10 times, any remaining precipitate is less than 5 mm in height from the bottom. 1: After shaking 10 times, any remaining precipitate is at least 5 mm high from the bottom. The practical level is 3 to 5.

[0112] Table 3-1

[0113] Table 3-2

[0114] Table 3-3

Claims

1. An organic solvent-based gravure ink for film containing a pigment, a polyurethane resin, a vinyl chloride copolymer resin and / or a cellulose resin, and an acidic compound, The acidic compound comprises a block copolymer containing a polyether-derived structure, a polyester structure derived from caprolactone and / or valerolactone, and a phosphate group. An organic solvent-based gravure ink for lamination and film.

2. The organic solvent-based gravure ink for film according to claim 1, wherein the pigment contains titanium dioxide.

3. The organic solvent-based gravure ink for film according to claim 1 or 2, wherein the polyurethane resin contains a structure derived from a dibasic acid, and the dibasic acid contains sebacic acid.

4. The organic solvent-based gravure ink for film according to claim 3, wherein the sebacic acid content is 50% by mass or more of the total mass of dibasic acids.

5. The organic solvent-based gravure ink for film according to claim 1 or 2, wherein the polyurethane resin contains a structure derived from polyisocyanate, and the polyisocyanate comprises an aromatic polyisocyanate and an aliphatic polyisocyanate.

6. The organic solvent-based gravure ink for film according to claim 5, wherein the content of aromatic polyisocyanate is 50% by mass or more of the total mass of polyisocyanate.

7. Furthermore, the organic solvent-based gravure ink for film according to claim 1 or 2 further contains a fatty acid amide.

8. Furthermore, the organic solvent-based gravure ink for film according to claim 1 or 2 further contains a chlorinated polypropylene resin.

9. A printed article having a printed layer on a substrate 1 made of an organic solvent-type gravure ink for film as described in claim 1 or 2.

10. A laminate comprising, at least, a substrate 1, a printing layer made of the organic solvent-type gravure ink for film described in claim 1 or 2, and a substrate 2, in this order.

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