Gravure printing inks and printed materials using them

Abstract

To provide a gravure printing ink excellent in storage stability, friction resistance, heat resistance, oil resistance and printing aptitude of the ink, in particular, excellent in adhesiveness to a substrate, antiblocking property to a vinyl chloride film, and antiblocking property to an antifogging film when printed and wound.SOLUTION: A gravure printing ink contains a binder resin, a bisamide, a chelating agent, and an organic solvent, wherein the binder resin contains two kinds of resins formed of a combination of a polyurethane resin and a vinyl chloride resin, a combination of a polyamide resin and a cellulose resin, or a combination of a polyurethane resin and a cellulose resin, and the chelating agent contains an acetylacetone-based titanium chelate and an acetoacetate alkyl-based titanium chelate.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to gravure printing ink and printed materials using the same. [Background technology]

[0002] In recent years, it has become common for product packaging and other wrapping materials to be printed for decorative or surface protection purposes. Furthermore, the design, aesthetic appeal, and sense of luxury of printed materials can stimulate consumer purchasing intent, and therefore have significant industrial value.

[0003] On the other hand, food manufacturers and printing and processing companies are increasingly demanding higher quality and performance from surface printing inks due to the diversification of packaging materials and the sophistication of packaging technology. Surface printing inks include flexographic inks, offset inks, gravure printing inks, and others, but gravure printing inks are widely used from a productivity standpoint because of their good printing speed.

[0004] Gravure printing inks require various performance characteristics, including not only print quality but also adhesion to the substrate, blocking resistance to prevent ink from bleeding or adhering to the back of the substrate when printed and wound up, abrasion resistance to prevent damage to the printed surface, heat resistance during bag making, and oil resistance to oils and fats.

[0005] As gravure printing inks with excellent adhesion and various resistances, for example, gravure printing inks containing a binder resin in which polyurethane resin and cellulose derivative and / or vinyl chloride-vinyl acetate copolymer are in a specified ratio, a chelating agent and a polyamide resin having a specific mass-average molecular weight (Patent Document 1), a gravure printing ink composition in which the content ratio of polyamide resin and cellulose derivative using either tall oil fatty acid or rice bran fatty acid as a reaction raw material and the content of each ink composition are specified (Patent Document 2), a gravure printing ink composition containing a binder resin and hydrocarbon wax, with the hardness (penetration) and content of the hydrocarbon wax specified (Patent Document 3), and a gravure printing ink composition containing a pigment, binder resin, hydrocarbon wax and chlorinated polyolefin resin, with the physical properties and content of the hydrocarbon wax and chlorinated polyolefin resin specified (Patent Document 4) have been proposed. However, with these technologies, it was difficult to satisfy the requirements for adhesion to the substrate and blocking resistance when printing on anti-fog films coated or kneaded with surfactants, or when the winding load of the printed anti-fog film and the environmental conditions (temperature and humidity) were affected. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 6599678 [Patent Document 2] Patent No. 6707680 [Patent Document 3] Japanese Patent Publication No. 2018-053014 [Patent Document 4] Japanese Patent Publication No. 2019-059923 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention aims to provide a gravure printing ink that exhibits good storage stability, abrasion resistance, heat resistance, oil resistance, and printability, and is particularly excellent in adhesion to substrates, resistance to blocking on vinyl chloride sheets, and resistance to blocking on anti-fogging films when printed and wound up. [Means for solving the problem]

[0008] As a result of diligent research into the aforementioned problems, the inventors have found that the above problems can be solved by using the gravure printing ink described below, and have thus come to present invention.

[0009] In other words, the present invention relates to a gravure printing ink containing a binder resin, a bisamide, a chelating agent, and an organic solvent, wherein the binder resin comprises two types of resins consisting of a combination of polyurethane resin and vinyl chloride resin, a combination of polyamide resin and cellulose resin, or a combination of polyurethane resin and cellulose resin, and the chelating agent comprises acetylacetone-based titanium chelate and alkyl acetoacetate-based titanium chelate.

[0010] The present invention also relates to the above-mentioned gravure printing ink, wherein the molecular weight of the bisamide is 600 to 2,000.

[0011] The present invention also relates to the above-mentioned gravure printing ink, wherein the bisamide content is 0.1 to 5% by mass of the total mass of the printing ink.

[0012] The present invention also relates to the above-mentioned gravure printing ink, wherein the bisamide has an unsaturated hydrocarbon group.

[0013] The present invention also relates to the above-mentioned gravure printing ink, wherein the chelating agent content is 0.1 to 5% by mass of the total mass of the printing ink.

[0014] The present invention further relates to the above-mentioned gravure printing ink, which contains hydrocarbon wax particles.

[0015] The present invention further relates to the above gravure printing ink containing an antifoaming agent.

[0016] The present invention also relates to a printed matter having a printing layer made of the above gravure printing ink on a substrate. [Advantages of the Invention]

[0017] According to the present invention, it is possible to provide a gravure printing ink having good storage stability, abrasion resistance, heat resistance, oil resistance, and printing suitability of the ink, particularly excellent adhesion to a substrate, blocking resistance to a vinyl chloride sheet, and blocking resistance to an anti-fogging film when printed and wound up. [Embodiments for Carrying Out the Invention]

[0018] Hereinafter, embodiments of the present invention will be described in detail. However, the description of the constituent elements described below is an 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.

[0019] In the following description, "gravure printing ink" may be abbreviated as "ink composition" or "ink". Further, "part" means "part by mass" unless otherwise specified, and "%" means "% by mass".

[0020] The gravure printing ink of the present invention is particularly preferably used as a gravure printing ink for front printing. In the present invention, "front printing" refers to a printing method in which when printing on a plastic substrate or a paper substrate, a printed pattern or design can be confirmed when viewed from the printing layer side. When it is a laminate or a packaging bag, the outermost surface becomes the printing layer. The layer obtained by printing the gravure printing ink may be referred to as a "printing layer", an "ink layer", or an "ink film", which are synonymous.

[0021] [Binder Resin] Binder resin refers to the binding resin in the ink. In this invention, the binder resin includes two types of resins, consisting of a combination of polyurethane resin and vinyl chloride resin, a combination of polyamide resin and cellulose resin, or a combination of polyurethane resin and cellulose resin.

[0022] <Polyurethane resin> When the ink of the present invention contains a polyurethane resin, the polyurethane resin plays a role in improving printability and lamination strength. A polyurethane resin is a resin having urethane bonds, and examples include a polyurethane resin composed of a polyol and a polyisocyanate, or a polyurethane urea resin obtained by reacting a urethane polymer of terminal isocyanates composed of a polyol and an isocyanate with a chain extender such as a polyamine. Examples of manufacturing methods include those described in Japanese Patent Publication No. 2013-256551 and Japanese Patent Publication No. 2016-043600. A preferred form of the polyurethane resin is a polyurethane resin having urethane bonds obtained by reacting a polyol component containing an aliphatic diol with a polyisocyanate.

[0023] (Polyol) Polyols preferably have an average of 1.7 to 2.3 hydroxyl groups per molecule, and more preferably an average of 2. Examples of polyols include polyether polyols such as polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran, etc., polyester polyols which are dehydration condensates of glycols such as diethylene glycol, triethylene glycol, dipropylene glycol, and dipropylene glycol with dibasic acids, polycarbonate polyols, polybutadiene glycols, polyols obtained by adding ethylene oxide or propylene oxide to bisphenol A, dimer diols, castor oil polyols, hydrogenated castor oil polyols, and various other known polyols. These can be used individually or in combination of two or more. The polyol may also contain biomass-derived compounds or raw materials (biomass raw materials) as constituent elements.

[0024] The number-average molecular weight of the polyol is preferably 300 or more, more preferably 500 to 6000, and even more preferably 1000 to 3000, in order to maintain the solubility of the polyurethane resin and its resistance to blocking on the anti-fogging substrate.

[0025] In the present invention, polyester polyols are preferred among polyols from the viewpoint of adhesion to polyester films and polyolefin films used as substrates. Furthermore, when two or more polyols are used in combination, it is more preferable that the polyester polyol be present in an amount of 40% by mass or more of the total mass of polyols, from the viewpoint of adhesion to the substrate and blocking resistance.

[0026] The polyester polyol preferably contains polyester-derived structural units consisting of a dibasic acid, including an aliphatic dibasic acid having 5 to 11 carbon atoms, and a diol. More preferably, the aliphatic dibasic acid has 6 to 10 carbon atoms, resulting in good adhesion to the substrate and good blocking resistance to the anti-fogging film. Furthermore, as the number of carbon atoms in the aliphatic dibasic acid increases, alcohol resistance improves.

[0027] (Aliphatic diols) The polyol constituting the polyurethane resin preferably contains an aliphatic diol. Examples of aliphatic diols include linear diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, and 1,9-nonanediol; branched diols such as 1,2-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, butylethylpropanediol, and methylnonanediol; and alicyclic diols such as cyclohexanedimethanol and cyclohexanediol. Multiple types may be used in combination. Among these, aliphatic diols having an alkyl group with 1 to 6 carbon atoms as a substituent are preferred because they have excellent adhesion to the substrate, enhance the solubility of the polyurethane resin, and improve printability. More specifically, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, butylethylpropanediol, 2-methyl-1,3-propanediol, and neopentyl glycol are preferably used.

[0028] Furthermore, it is preferable to use a combination of an aliphatic diol with a molecular weight of 180 or less and other polyols. Examples of other polyols include aromatic diols and aliphatic diols with a molecular weight exceeding 180, and these may be used in combination. Structural units derived from aliphatic diols with a molecular weight of 180 or less enhance the density of urethane bonds, imparting crystallinity and cohesiveness, while other polyol-derived structural units contribute to flexibility and adhesion. Therefore, both blocking resistance and substrate adhesion can be achieved, and oil resistance is also good. The content of aliphatic diol-derived structural units with a molecular weight of 180 or less in the total amount of polyol-derived structural units is preferably 10 to 60% by mass, and more preferably 20 to 40% by mass. A content of 10% by mass or more improves the cohesiveness of the urethane bonds obtained by reaction with isocyanate, resulting in excellent blocking resistance to anti-fogging films. A content of 60% by mass or less allows for good maintenance of the polyurethane resin's solubility in solvents.

[0029] (Polyisocyanate) As the polyisocyanate, diisocyanates are preferred. For example, aromatic diisocyanates such as 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyli isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylenediisocyanate, 1,4-phenylenediisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropyl diisocyanate, methylene diisocyanate, and 2,2,4 Examples include aliphatic diisocyanates such as trimethylhexamethylene diisocyanate, alicyclic diisocyanates such as cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanate-methyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer isocyanates obtained by converting the carboxyl group of a dimer acid to an isocyanate group. Among these, isophorone diisocyanate and hexamethylene diisocyanate are preferred.

[0030] To obtain the polyurethane resin used in the present invention, the reaction can be carried out such that the reaction molar ratio (molar equivalent of NCO / molar equivalent of OH) between NCO derived from polyisocyanate and OH derived from polyol is preferably 0.5 to 3, more preferably 1.05 to 2. Then, if necessary, the chain can be extended with a polyamine as described later. Furthermore, a reaction stopper can be used to prevent overreaction.

[0031] The above urethane formation reaction may be carried out in an organic solvent or without a solvent. When using an organic solvent, it is advisable to select it appropriately in terms of temperature, viscosity during the reaction, and control of side reactions. When carrying out the urethane formation reaction without a solvent, it is desirable to raise the temperature to a viscosity that allows for sufficient stirring in order to obtain a uniform polyurethane resin. The urethane formation reaction is preferably carried out for 10 minutes to 5 hours, and the endpoint of the reaction can be determined by viscosity measurement, NCO-derived peak by IR measurement, NCO% measurement by titration, etc.

[0032] The polyamines used for chain extension are preferably aliphatic diamines such as ethylenediamine, 1,4-butanediamine, isophoronediamine, and aminoethylethanolamine. Glycols such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, and triethylene glycol can also be used as chain extenders. Other reaction stoppers include monoalcohols such as methanol and ethanol, alkylamines such as n-propylamine, n-butylamine, and di-n-butylamine, and alkanolamines such as monoethanolamine and diethanolamine.

[0033] The polyurethane resin preferably has a weight-average molecular weight of 8,000 to 80,000, and more preferably 10,000 to 60,000. The glass transition temperature is preferably 0°C or lower, more preferably -40°C to -5°C, and even more preferably -35°C to -10°C. This is because it provides good affinity with vinyl chloride resins or cellulose resins. Furthermore, the polyurethane resin is preferably one having amino groups and / or hydroxyl groups. If it has amino groups, the amine value is preferably 0.5 to 20 mg KOH / g, and more preferably 1 to 15 mg KOH / g. If it has hydroxyl groups, the hydroxyl value is preferably 0.5 to 30 mg KOH / g, and more preferably 1 to 20 mg KOH / g. When the amine value and / or hydroxyl value are within the above ranges, the adhesion to the substrate is improved.

[0034] <Polyamide resin> The polyamide resin used in the present invention is not limited to the following, but is preferably a thermoplastic polyamide soluble in organic solvents that can be obtained by polycondensation of a polybasic acid and a polyhydric amine. In particular, it is more preferably a polyamide resin containing a reaction product of an acid component containing polymerized fatty acids and / or dimer acids and an aliphatic and / or aromatic polyamine, and even more preferably a polyamide resin that partially contains primary and secondary monoamines.

[0035] The polybasic acids used as raw materials for polyamide resins are not limited to the following, but include adipic acid, sebacic acid, azelaic acid, phthalic anhydride, isophthalic acid, suberic acid, glutaric acid, fumaric acid, pimelic acid, oxalic acid, malonic acid, succinic acid, maleic acid, terephthalic acid, 1,4-cyclohexyldicarboxylic acid, trimellitic acid, dimeric acid, hydrogenated dimeric acid, polymerized fatty acids, etc. Among these, polyamide resins containing structures derived from dimeric acid or polymerized fatty acids are preferred, and it is more preferable that the polyamide resin contains 50% by mass or more of such structures. Here, polymerized fatty acids are obtained by cyclization reactions of unsaturated fatty acids, etc., and include monobasic fatty acids, dimerized polymerized fatty acids (dimeric acid), trimerized polymerized fatty acids, etc. The fatty acids constituting polymerized fatty acids or dimeric acid can preferably be derived from natural oils such as soybean oil, palm oil, or rice bran oil, and those obtained from oleic acid or linoleic acid are preferred. In addition to polybasic acids, monocarboxylic acids can also be used in combination. Examples of monocarboxylic acids that can be used in combination include acetic acid, propionic acid, lauric acid, palmitic acid, benzoic acid, and cyclohexanecarboxylic acid.

[0036] Examples of polyhydric amines used as raw materials for polyamide resins include polyamines. Examples of polyamines include aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, and methylaminopropylamine; aliphatic polyamines such as diethylenetriamine and triethylenetetramine; alicyclic polyamines such as cyclohexylenediamine and isophoronediamine; aromatic aliphatic polyamines such as xylylenediamine; and aromatic polyamines such as phenylenediamine and diaminodiphenylmethane. Furthermore, the formulation may also contain primary or secondary monoamines. Examples of primary or secondary monoamines include n-butylamine, octylamine, diethylamine, monoethanolamine, monopropanolamine, diethanolamine, and dipropanolamine.

[0037] In polyamide resins, the molecular weight distribution of the tetrahydrofuran-soluble portion, measured by gel permeation chromatography (GPC), preferably has an area ratio (area percentage) of molecular weights of 3,000 or less of 10-50% of the total peak area of ​​the molecular weight distribution curve, and more preferably 20-40%. In the low molecular weight range of 3,000 or less, polyamide resins melt at low temperatures, making them easier to wet and spread on the substrate, resulting in good adhesion to the substrate. In one embodiment, the ink contains a polyamide resin, a cellulose resin, a fatty acid amide, and a chelating agent with a molecular weight of 3,000 or less and an area percentage of 10 to 50%, thereby achieving both adhesion to the substrate and resistance to blocking. The area ratio is the area percentage within the range of Log(3,000) or less in a molecular weight distribution diagram where the vertical axis is the area percentage (%) of molecular weight M and the horizontal axis is the common logarithm LogM of molecular weight M.

[0038] The measurement conditions for the above GPC can be a polystyrene-based measurement method, with RI reflection as the detection method, an efflux rate of 0.1 to 0.5 ml / min, a column temperature of 30 to 50°C, and a Showa Denko Shodex GPC-104 measuring instrument.

[0039] The polyamide resin is preferably contained in an amount of 10 to 50% by mass, and more preferably 25 to 45% by mass, relative to the total solid content of the ink composition. When the amount is 10% by mass or more, the drying properties of the printing ink are improved, and when it is 50% by mass or less, the fluidity and leveling properties of the printing ink are improved, resulting in good storage stability and printability.

[0040] Furthermore, the polyamide resin preferably has a softening point of 80 to 140°C, and more preferably 90 to 130°C. In the above embodiment, the ink film becomes stronger. When the softening point is 80°C or higher, the surface tack breakage of the ink film of the printed material is good, preventing blocking. When the softening point is 140°C or lower, the ink film becomes flexible, improving adhesion to the substrate. Note that the softening point is the value measured according to JIS K2207 (ring-ball method). Preferred polyamide resins include the Rheomide series (manufactured by Kao Corporation) and the Polymide series (manufactured by Sanyo Chemical Industries, Ltd.).

[0041] <Vinyl chloride resin> The vinyl chloride resin used in the present invention is not particularly limited as long as it contains structural units derived from vinyl chloride and structural units derived from other monomers. Among these, vinyl chloride-vinyl acetate copolymer resins are preferred.

[0042] (Vinyl chloride-vinyl acetate copolymer resin) Vinyl chloride-vinyl acetate copolymer resin is obtained by copolymerizing vinyl chloride monomer and vinyl acetate monomer. The weight-average molecular weight of the vinyl chloride-vinyl acetate copolymer resin is preferably 5,000 to 100,000, and more preferably 20,000 to 70,000. 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 100% by mass of the solid content of the vinyl chloride-vinyl acetate copolymer resin. In this case, solubility in organic solvents is improved, and the adhesion to the substrate and the physical properties of the ink layer are also improved.

[0043] Furthermore, vinyl chloride-vinyl acetate copolymer resins preferably have hydroxyl groups, and vinyl chloride-vinyl acetate copolymer resins having hydroxyl groups can be obtained by further using vinyl alcohol in copolymerization or by saponifying a portion of the vinyl acetate. When the vinyl chloride-vinyl acetate copolymer resin has hydroxyl groups, its hydroxyl value is preferably 50 to 180 mg KOH / g, and more preferably 70 to 160 mg KOH / g.

[0044] The monomer ratios of vinyl chloride, vinyl acetate, and vinyl alcohol affect the properties of the resin coating and its dissolution behavior. For example, vinyl chloride imparts toughness and hardness to the resin coating, vinyl acetate imparts adhesion and flexibility, and vinyl alcohol imparts good solubility in polar solvents. Furthermore, the glass transition temperature of the vinyl chloride-vinyl acetate copolymer resin is preferably 50°C to 90°C.

[0045] In one embodiment, the combination of the polyurethane resin and the vinyl chloride resin functions effectively as a binder resin. When other resins are used in combination, it is preferable that the total amount of polyurethane resin and vinyl chloride resin be 60% by mass or more, and more preferably 80% by mass or more, of the total amount of binder resin. This is because it results in good adhesion to the substrate. Furthermore, when the binder resin contains the above-mentioned polyurethane resin and vinyl chloride resin, the mass ratio of their solid content (polyurethane resin / vinyl chloride resin) is preferably 95 / 5 to 50 / 50. This blending ratio results in good adhesion to the substrate, blocking resistance, and printability.

[0046] <Cellulose resin> Examples of cellulose-based resins include cellulose acetate propionate, cellulose acetate butyrate and other cellulose ester resins, nitrocellulose, hydroxyalkylcellulose, and carboxyalkylcellulose. Cellulose ester resins preferably have an alkyl group, and examples of such alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, and hexyl groups, and the alkyl group may also have substituents. Of the above, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferred as cellulose-based resins. Nitrocellulose is particularly preferred. The weight-average molecular weight of the cellulose resin is preferably 5,000 to 200,000, and more preferably 10,000 to 50,000. Furthermore, the glass transition temperature of the cellulose resin is preferably 120°C to 180°C. In one embodiment, the combined use of the cellulose resin with a polyamide resin or polyurethane resin further improves the ink film properties such as blocking resistance, scratch resistance, and heat resistance.

[0047] (Nitrocellulose) The above-mentioned nitrocellulose is preferably obtained as a nitrate ester by reacting natural cellulose with nitric acid, thereby substituting three hydroxyl groups in the six-membered ring of the anhydrous glucopyranose group in the natural cellulose with nitrate groups, and is preferably in the range of 20 to 200, and more preferably 30 to 150, with an average degree of polymerization in the range of 20 to 200. When the average degree of polymerization of nitrocellulose is 20 or higher, the strength of the ink layer and the abrasion resistance are improved. When the average degree of polymerization of nitrocellulose is 200 or lower, the solubility in solvents, the low-temperature stability of the ink, and the compatibility with the co-used resin are improved. The molecular weight of the nitrocellulose is preferably 5,000 to 200,000 by weight average, and more preferably 10,000 to 50,000. Furthermore, the glass transition temperature of the nitrocellulose is preferably 120°C to 180°C, and the nitrogen content is preferably 10.5 to 12.5% ​​by mass. Preferred nitrocellulose resins include the TR series (manufactured by TNC Industrial) and the DLX series (manufactured by Nobel Enterprises).

[0048] In one embodiment, a combination of the polyamide resin and the cellulose resin, or a combination of the polyurethane resin and the cellulose resin, functions effectively as a binder resin. When the binder resin includes a combination of the polyamide resin and the cellulose resin, or a combination of the polyurethane resin and the cellulose resin, the solid content mass ratio (polyamide resin or polyurethane resin) / (cellulose resin) is preferably 95 / 5 to 40 / 60. This combination and blending ratio results in good adhesion to the substrate, as well as good resistance to various aspects of the printing ink layer, such as blocking resistance, abrasion resistance, and heat resistance.

[0049] <Bisamide> The gravure printing ink of the present invention contains bisamide. The bisamide content is preferably 0.1 to 5% by mass, and more preferably 0.2 to 3% by mass, in the ink composition. When the bisamide content is 0.1% by mass or more, blocking resistance is improved, and when it is 5% by mass or less, printability and oil resistance are improved.

[0050] Also, the molecular weight of the bisamide is preferably 600 or more and 2,000 or less, more preferably 650 or more and 1,500 or less, and even more preferably 1,000 or less. When a mixture of plural bisamides is used, the above molecular weight refers to the weight average molecular weight. When the molecular weight of the bisamide is 600 or more, the blocking resistance is improved. When the molecular weight is 2,000 or less, it is likely to orient on the surface of the ink film after printing, exhibiting slipperiness and resulting in good blocking resistance and abrasion resistance. By using the binder resin and the bisamide within the above molecular weight range in combination, the blocking resistance is further improved. The bisamide has more amide groups in one molecule than the monoamide and a relatively lower molecular weight than the polyamide having more amide groups in one molecule. Therefore, it is considered that there are many amide groups oriented on the surface of the ink film, and the blocking resistance is further improved due to the interaction with the substrate contacting the ink film.

[0051] The bisamide is preferably represented by the following general formula (1) or general formula (2). General formula (1) R 6 -CONH-R 2 -HNCO-R 3 General formula (2) R 4 -NHCO-R 5 -CONH-R 6 (In the formula, R 1 , R 3 , R 4 , and R 6 represent aliphatic hydrocarbon groups having 10 to 25 carbon atoms, which may be the same or different, and R 2 and R 5 represent an alkylene group or an arylene group.)

[0052] Examples of bisamides include methylenebisstearate, ethylenebiscaprate, ethylenebislaurate, ethylenebisstearate, ethylenebishydroxystearate, ethylenebisbehenamide, hexamethylenebisstearate, hexamethylenebisbehenamide, hexamethylenebishydroxystearate, ethylenebisoleamide, ethylenebiserucamide, hexamethylenebisoleamide, N,N'-distearyladipamide, N,N'-distearylsebacinamide, N,N'-dioleyladipamide, and N,N'-dioleylsebacinamide.

[0053] The melting point of bisamides is preferably 50°C to 150°C. Examples 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), and hexamethylenebishydroxystearate (melting point Examples include ethylenebisoleamide (melting point 119°C), ethylenebiserucamide (melting point 120°C), hexamethylenebisoleamide (melting point 110°C), N,N'-distearyladibamide (melting point 141°C), N,N'-distearylsebacinamide (melting point 136°C), N,N'-dioleyladibamide (melting point 118°C), and N,N'-dioleylsebacinamide (melting point 113°C).

[0054] The fatty acids constituting the bisamide are preferably saturated fatty acids having 10 to 22 carbon atoms and / or unsaturated fatty acids having 16 to 25 carbon atoms, and more preferably saturated fatty acids having 12 to 18 carbon atoms and / or unsaturated fatty acids having 18 to 22 carbon atoms. Examples of saturated fatty acids include lauric acid, palmitic acid, stearic acid, behenic acid, and hydroxystearic acid, while examples of unsaturated fatty acids include oleic acid and erucic acid. Bisamides comprising at least one fatty acid selected from the group consisting of lauric acid, palmitic acid, stearic acid, behenic acid, hydroxystearic acid, oleic acid, and erucic acid are particularly preferred. Furthermore, the presence of unsaturated fatty acids is preferable in terms of solubility in organic solvents and printability.

[0055] Furthermore, the present invention may include bisamides other than those represented by the above general formula (1) or general formula (2), as long as the effects and functions of the present invention are not impaired, and known bisamides can be used.

[0056] <Chelating agent> The gravure printing ink of the present invention contains a chelating agent. The inclusion of a chelating agent improves the cohesive force of the ink film, enhancing adhesion to the substrate, as well as improving the abrasion resistance and oil resistance of the ink film. As the chelating agent, an organotitanium compound having a Ti-OC type bond in one molecule is preferred.

[0057] Specific examples of organotitanium compounds include titanium alkoxides such as tetraisopropyl titanate, tetran-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, tetramethyl titanate, and tetrastearyl titanate, as well as titanium chelates such as triethanolamine titanate, titanium acetylacetonate, titanium lactate, octylene glycol titanate, titanium tetraacetylacetonate, titanium ethylacetoacetate, diisopropoxytitanium bis(acetylacetonate), propanedioxytitanium bis(ethylacetylacetoate), and diisopropoxytitanium bis(ethylacetoacetate). Among these, acetylacetone-based titanium chelates such as titanium acetylacetonate, titanium tetraacetylacetonate, and diisopropoxytitanium bis(acetylacetonate), and alkyl acetoacetate-based titanium chelates such as titanium ethylacetoacetate, propanediokistitanium bis(ethylacetylacetate), and diisopropoxytitanium bis(ethylacetoacetate) are preferred.

[0058] In the present invention, by using the above-mentioned acetylacetone-based titanium chelate and alkyl acetoacetate-based titanium chelate in combination, the storage stability, solubility, and printability of the ink are improved. The mass ratio of acetylacetone-based titanium chelate to alkyl acetoacetate-based titanium chelate (acetylacetone-based titanium chelate / alkyl acetoacetate-based titanium chelate) is not particularly limited, but is preferably 99:1 to 1:99, more preferably 90:10 to 10:90, even more preferably 80:20 to 20:80, and particularly preferably 30:70 to 70:30.

[0059] Furthermore, by using the bisamide in combination with the acetylacetone-based titanium chelate and alkyl acetoacetate-based titanium chelate, blocking resistance is further improved. In order to achieve both adhesion to the substrate and blocking resistance, the mass ratio of the bisamide to the acetylacetone-based titanium chelate and alkyl acetoacetate-based titanium chelate (total amount of bisamide / acetylacetone-based titanium chelate and alkyl acetoacetate-based titanium chelate) is preferably 10:90 to 90:10, and more preferably 15:85 to 85:15.

[0060] The chelating agent content is preferably 0.1 to 5% by mass of the total mass of the gravure printing ink. When the chelating agent content is 0.1% by mass or more, adhesion to the substrate and blocking resistance are improved, and when it is 5.0% by mass or less, the storage stability and printability of the ink are improved.

[0061] <Hydroxide wax particles> The gravure printing ink of the present invention preferably uses hydrocarbon wax particles. Examples of hydrocarbon waxes include polyolefin wax and paraffin wax, and the content of hydrocarbon wax particles is preferably 0.1 to 3% by mass, and more preferably 0.3 to 2.5% by mass, of the total mass of the gravure printing ink. By using hydrocarbon wax particles in combination with the binder resin of the present invention, the abrasion resistance of the ink film is further improved.

[0062] <Antifoaming agent> The gravure printing ink of the present invention preferably contains an antifoaming agent. The antifoaming agent prevents foam generated during printing from transferring to the printed material, which would result in printing defects (poor leveling). Examples of antifoaming agents include oil-based antifoaming agents, polymer-based antifoaming agents, and silicone-based antifoaming agents. In the present invention, it is preferable to use a polymer-based antifoaming agent and / or a silicone-based antifoaming agent, and from the viewpoint of compatibility, a polymer-based antifoaming agent is more preferable.

[0063] <Colorants, Pigments> The gravure printing ink of the present invention may contain a colorant. Pigments are preferred as colorants. The pigments usable in the present invention are not particularly limited, and various inorganic and organic pigments that can be used in printing inks and paints can be suitably used. Examples of inorganic pigments include colored pigments such as titanium dioxide, red iron oxide, Prussian blue, ultramarine, carbon black, and graphite, and extender pigments such as calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, and talc. Suitable organic pigments include soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments. However, the pigments are not limited to these, and those listed by their generic names in the color index can be used as appropriate. The pigment content is preferably 0.5 to 50% by mass in the total amount of ink.

[0064] <Additives> Various additives may be used in the gravure printing ink of the present invention as needed. Examples of additives include pigment dispersants, extender pigments, inorganic fine particles, leveling agents, and adhesion aids. Specifically, examples of additives include pigment dispersants to improve the dispersibility of pigments, extender pigments to improve drying properties and film opacity, inorganic fine particles to provide anti-slip properties, leveling agents to improve leveling properties, and adhesion aids to improve adhesion to the substrate.

[0065] <Organic solvents> The solvents used in the ink composition of the present invention mainly include alcohol-based organic solvents such as methanol, ethanol, n-propanol, isopropanol, and butanol; ketone-based organic solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester-based organic solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; aliphatic hydrocarbon-based organic solvents such as n-hexane, n-heptane, and n-octane; and alicyclic hydrocarbon-based organic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane, and cyclooctane. It is preferable to use a mixture of these solvents, taking into consideration the solubility and drying properties of the binder resin. It is preferable that these organic solvents be contained in an amount of 20% by mass or more of the total amount of ink. Furthermore, in order to address odor and environmental concerns during printing, it is preferable that the organic solvent mainly consists of a mixed solvent of ester-based organic solvent and alcohol-based organic solvent, and that the mass ratio (ester-based organic solvent: alcohol-based organic solvent) is preferably 50:50 to 90:10.

[0066] <Manufacturing of gravure printing inks> One method for producing the gravure printing ink of the present invention involves first uniformly stirring and mixing a composition containing a pigment, a binder resin, a fatty acid amide, a chelating agent, an organic solvent, and optionally a pigment dispersant, an antifoaming agent, etc., using a bladed agitator. Then, the mixture is dispersed using various kneading machines, such as a bead mill, ball mill, sand mill, attritor, roll mill, pearl mill, etc., and further mixing in other resins and additives. In particular, it is preferable to include a step of kneading and dispersing the pigment-containing composition using a bead mill.

[0067] <Base material> The printing ink of the present invention can be printed on a substrate to produce a printed material. The substrate is not particularly limited, but is preferably a film substrate. Examples include polyolefin substrates such as polyethylene and polypropylene, polyester substrates such as polyethylene terephthalate, polycarbonate, and polylactic acid, polystyrene-based substrates such as polystyrene, AS resin, and ABS resin, film substrates such as nylon substrates, polyamide substrates, polyvinyl chloride substrates, polyvinylidene chloride substrates, and cellophane substrates, and film substrates made of composite materials thereof. The plastic substrate may have metals or metal oxides such as silica, alumina, and aluminum deposited on it, and the deposited surface may be further coated with a paint such as polyvinyl alcohol. Generally, the surface of the substrate to be printed is often subjected to surface treatment such as corona treatment. Furthermore, the substrate can also be a film obtained by processing a plastic film in advance by coating or kneading an anti-fogging agent, or surface coating or kneading a matting agent. Furthermore, the base material may be a single layer or a laminate (base material layer) in which two or more base materials are stacked. The base materials constituting the base material layer may be the same or different. In particular, a polyolefin substrate is preferred. The polyolefin substrate may or may not be surface-treated.

[0068] The above-mentioned anti-fogging agent is preferably a surfactant, and for example, one or more ionic surfactants such as polyhydric alcohol fatty acid esters such as sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene fatty acid esters, glycerin fatty acid esters, or ethylene oxide adducts may be used.

[0069] <Printed material> A printed material can be obtained by printing the gravure printing ink of the present invention onto a substrate to form a printed layer. For example, a printed material can be obtained by printing on a substrate using the gravure printing ink of the present invention, and then removing volatile components to form a printed layer. Gravure printing is preferred as the printing method. The gravure printing ink of the present invention is diluted with a diluent solvent to a viscosity and concentration suitable for gravure printing, and supplied to each printing unit, either alone or in mixtures, for printing. After that, the ink layer is fixed by drying in an oven to obtain a printed material. Furthermore, inks that do not contain colorants such as pigments are also called overprint varnishes (OP varnishes) and can be used to form an OP layer. Specifically, after forming the above-mentioned ink layer containing a colorant, printing is performed to cover the ink layer, and the OP layer can be formed by drying in an oven. [Examples]

[0070] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the present invention, parts and % refer to parts by mass and mass %, respectively, unless otherwise noted. Examples 10, 11, 27, 28, 29, 44, and 45 are for reference only.

[0071] <Weight-average molecular weight and number-average molecular weight> The weight-average molecular weight (Mw) and number-average molecular weight (Mn) were determined by GPC (gel permeation chromatography). The molecular weight distribution was measured using Showa Denko's "Shodex GPC-104," and the polystyrene-equivalent molecular weight was determined. The measurement conditions are shown below. Columns: Use the following multiple columns linked in series. Two Shodex LF-404 tubes manufactured by Showa Denko. Showa Denko Shodex LF-G Detector: RI (Differential Refractometer), Column temperature: 40°C, Eluent: Tetrahydrofuran Flow rate: 0.3mL / min

[0072] <Preparation of polyurethane resin solution (PU1)> In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 103.2 parts of polyester polyol, a condensate of 3-methyl-1,5-pentanediol and adipic acid with a number average molecular weight of 2000, 35.2 parts of neopentyl glycol, 121.4 parts of isophorone diisocyanate, 0.03 parts of stannous ethylhexylate, and 65.1 parts of ethyl acetate were charged. The mixture was reacted at 90°C for 2 hours under a nitrogen stream, and 165.3 parts of ethyl acetate was added and cooled to obtain 490.2 parts of a solvent solution of the terminal isocyanate prepolymer. Next, the obtained 490.2 parts of the terminal isocyanate prepolymer was gradually added at room temperature to a mixture of 33.6 parts of isophorone diamine, 1.2 parts of di-n-butylamine, 237.5 parts of ethyl acetate, and 200.6 parts of isopropyl alcohol, and the mixture was then reacted at 50°C for 1 hour. Subsequently, 5.3 parts of isophorone diisocyanate were added to adjust the viscosity, and then the solid content was adjusted to 30% with a solvent of ethyl acetate / isopropyl alcohol mixed in a mass ratio of 1 / 2 to obtain a polyurethane resin solution (PU1) with a weight-average molecular weight of 40,000.

[0073] <Preparation of polyurethane resin solution (PU2)> In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 103.2 parts of a biomass-derived polyester polyol, a condensate of 3-methyl-1,5-pentanediol and sebacic acid with a number-average molecular weight of 2000, 35.2 parts of neopentyl glycol, 121.4 parts of isophorone diisocyanate, 0.03 parts of stannous 2-ethylhexylate, and 65.1 parts of ethyl acetate were charged. The mixture was reacted at 90°C for 2 hours under a nitrogen stream, and 165.3 parts of ethyl acetate was added and cooled to obtain 490.2 parts of a solvent solution of the terminal isocyanate prepolymer. Next, the obtained 490.2 parts of the terminal isocyanate prepolymer was gradually added at room temperature to a mixture of 33.6 parts of isophorone diamine, 1.2 parts of di-n-butylamine, 237.5 parts of ethyl acetate, and 200.6 parts of isopropyl alcohol, and the mixture was then reacted at 50°C for 1 hour. Subsequently, 5.3 parts of isophorone diisocyanate were added to adjust the viscosity, and then the solid content was adjusted to 30% with a solvent of ethyl acetate / isopropyl alcohol mixed in a mass ratio of 1 / 2 to obtain a polyurethane resin solution (PU2) with a weight-average molecular weight of 40,000.

[0074] <Preparation of polyamide resin solution> A polyamide resin with the following specifications was synthesized, with reference to the examples in Japanese Patent Publication No. 6255123. Polyamide resin (1): (Mw) 7,172, (Mn) 1,928 Polyamide resin (2): (Mw) 13,604, (Mn) 2,269 30 parts of each polyamide resin were mixed and dissolved in 70 parts of a mixed solvent consisting of n-propyl acetate, ethyl acetate, isopropyl alcohol, and methylcyclohexane in a mass ratio of 20:20:20:40 to obtain polyamide resin solutions (PA1) and (PA2) with a solid content of 30%. Both polyamide resins (1) and (2) contain constituent units derived from dimer acid and have a softening point of 100 to 130°C. For polyamide resin (1), the area percentage of the total peak area in the molecular weight distribution curve for molecules with a molecular weight of 3,000 or less was 35.0%. For polyamide resin (2), the area percentage of the total peak area in the molecular weight distribution curve for molecules with a molecular weight of 3,000 or less was 27.9%.

[0075] <Preparation of vinyl chloride-vinyl acetate copolymer resin solution> 20 parts of vinyl chloride-vinyl acetate copolymer resin (manufactured by Nisshin Chemical Co., Ltd., product name Solvine TA5R) were mixed and dissolved in 80 parts of ethyl acetate to obtain a vinyl chloride-vinyl acetate copolymer resin solution with a solid content of 20%.

[0076] <Preparation of Nitrocellulose Solution> Thirty parts of nitrocellulose wetted with isopropyl alcohol (manufactured by TNC INDUSTRIAL, product name NC TR2) were mixed and dissolved in 70 parts of a mixed solvent consisting of n-propyl acetate:ethyl acetate:isopropyl alcohol:methylcyclohexane = 20:20:20:40 (mass ratio) to obtain a nitrocellulose solution with a solid content of 20%.

[0077] <Fatty acid amide> Bisamide(1):Hexamethylenebisoleamide (molecular weight) 650 Bisamide (2): A mixture of bisamides, in which fatty acids with a C6-C18 distribution are amide-bonded to hexamethylenediamine, and triamides, in which azelaic acid is amide-bonded. (Mw) 1,500 Bisamide(3): Ethylene bisstearamide (molecular weight) 590 Bisamide(4): Ethylenebislauric acid amide (molecular weight) 425 Monoamide: Palmitic acid amide (molecular weight) 250 Polyamide: (Mw) 3,800 (Manufactured by Sanyo Chemical Industries, Ltd., product name: Polyamide S-2460)

[0078] <Chelating agent> Titanium chelate (1): Diisopropoxytitanium bis(acetylacetonate) Titanium chelate (2): Diisopropoxytitanium bis(ethylacetoacetate)

[0079] <Hydrocarbon wax> Polyethylene wax (manufactured by Mitsui Chemicals, product name: High Wax 320MP) Paraffin wax (Micro Powders Co., Ltd., product name MP-22XF)

[0080] <Antifoaming agent> Polymer-based defoaming agent (manufactured by BYK, product name BYK-1752) Silicone-based defoaming agent (BASF product name EFKA SI2741)

[0081] <Example 1> Gravure printing ink (Ink S1) was prepared by kneading 46.7 parts of a mixed solvent consisting of 10 parts of phthalocyanine blue pigment (Toyo Color's Lionol Blue FG-7400G (CI Pigment Blue 15:4)), 34 parts of polyurethane resin (PU1), 6 parts of vinyl chloride-vinyl acetate copolymer resin solution, 1 part of bisamide (1), 0.5 parts of titanium chelate (1), 1 part of titanium chelate (2), 0.7 parts of polyethylene wax, 0.1 part of polymer-based defoamer, and n-propyl acetate:ethyl acetate:isopropyl alcohol:methylcyclohexane = 35:30:20:15 (mass ratio) in a sand mill (Eiger mill).

[0082] <Example 2> Gravure printing ink (Ink S2) was prepared by kneading 46.7 parts of a mixed solvent consisting of 10 parts of phthalocyanine blue pigment (Toyo Color's Lionol Blue FG-7400G (CI Pigment Blue 15:4)), 34 parts of polyurethane resin (PU2), 6 parts of vinyl chloride-vinyl acetate copolymer resin solution, 1 part of bisamide (1), 0.5 parts of titanium chelate (1), 1 part of titanium chelate (2), 0.7 parts of polyethylene wax, 0.1 part of polymer-based defoamer, and n-propyl acetate:ethyl acetate:isopropyl alcohol:methylcyclohexane = 35:30:20:15 (mass ratio) in a sand mill (Eiger mill).

[0083] <Examples 3-17> Gravure printing ink compositions (inks S3 to S17) were obtained in the same manner as in Example 1, except that the raw materials and mixing ratios listed in Table 1 were changed.

[0084] [Table 1]

[0085] <Example 18> Gravure printing ink (Ink S18) was obtained by kneading 23.3 parts of a mixed solvent consisting of 10 parts of phthalocyanine blue pigment (Toyo Color Co., Ltd. Lionol Blue FG-7400G (CI Pigment Blue 15:4)), 32 parts of polyamide resin solution (PA1), 31 parts of nitrocellulose solution, 2 parts of bisamide (1), 0.3 parts of titanium chelate (1), 0.7 parts of titanium chelate (2), 0.5 parts of paraffin wax, 0.2 parts of polymer-based defoamer, and n-propyl acetate:ethyl acetate:isopropyl alcohol:methylcyclohexane = 20:20:20:40 (mass ratio) in a sand mill (Eiger mill).

[0086] <Example 19> Gravure printing ink (Ink S19) was obtained by kneading 23.3 parts of a mixed solvent consisting of 10 parts of phthalocyanine blue pigment (Toyo Color Co., Ltd. Lionol Blue FG-7400G (CI Pigment Blue 15:4)), 32 parts of polyamide resin solution (PA2), 31 parts of nitrocellulose solution, 2 parts of bisamide (1), 0.3 parts of titanium chelate (1), 0.7 parts of titanium chelate (2), 0.5 parts of paraffin wax, 0.2 parts of polymer-based defoamer, and n-propyl acetate:ethyl acetate:isopropyl alcohol:methylcyclohexane = 20:20:20:40 (mass ratio) in a sand mill (Eiger mill).

[0087] <Examples 20-34> A gravure printing ink composition (inks S20-S34) was obtained in the same manner as in Example 18, except that the raw materials and mixing ratios were changed as shown in Table 2.

[0088] [Table 2]

[0089] <Example 35> Gravure printing ink (Ink S35) was prepared by kneading 37.4 parts of a mixed solvent consisting of 10 parts of phthalocyanine blue pigment (Toyo Color's Lionol Blue FG-7400G (CI Pigment Blue 15:4)), 34 parts of polyurethane resin (PU2), 15 parts of nitrocellulose solution, 1 part of bisamide (1), 0.5 parts of titanium chelate (1), 1 part of titanium chelate (2), 1 part of polyethylene wax, 0.1 part of polymer-based defoamer, and n-propyl acetate:ethyl acetate:isopropyl alcohol:methylcyclohexane = 35:30:20:15 (mass ratio) in a sand mill (Eiger mill).

[0090] <Example 36> Gravure printing ink (Ink S36) was prepared by kneading 37.4 parts of a mixed solvent consisting of 10 parts of phthalocyanine blue pigment (Toyo Color's Lionol Blue FG-7400G (CI Pigment Blue 15:4)), 34 parts of polyurethane resin (PU1), 15 parts of nitrocellulose solution, 1 part of bisamide (1), 0.5 parts of titanium chelate (1), 1 part of titanium chelate (2), 1 part of polyethylene wax, 0.1 part of polymer-based defoamer, and n-propyl acetate:ethyl acetate:isopropyl alcohol:methylcyclohexane = 35:30:20:15 (mass ratio) in a sand mill (Eiger mill).

[0091] <Examples 37-51> A gravure printing ink composition (inks S37-S51) was obtained in the same manner as in Example 35, except that the raw materials and mixing ratios were changed as shown in Table 3.

[0092] [Table 3]

[0093] <Comparative Examples 1-7> Gravure printing ink compositions (inks T1 to T7) were obtained in the same manner as in Example 1, except that the raw materials and mixing ratios were changed as shown in Table 4.

[0094] <Comparative Examples 8-14> Gravure printing ink compositions (inks T8 to T14) were obtained in the same manner as in Example 18, except that the raw materials and mixing ratios were changed as shown in Table 4.

[0095] <Comparative Examples 15-21> Gravure printing ink compositions (inks T15 to T21) were obtained in the same manner as in Example 35, except that the raw materials and mixing ratios were changed as shown in Table 4.

[0096] [Table 4]

[0097] <Manufacturing (printing) of gravure printed materials for cover printing> The gravure printing ink obtained in Example 1 was diluted with a diluent solvent (n-propyl acetate:ethyl acetate:isopropyl alcohol:methylcyclohexane = 35:30:20:15 (mass ratio)), adjusted to 15 seconds in a Zahn cup No. 3, and used as a diluted ink for printing. Next, a polypropylene film (D-SHNY01, 28 μm, manufactured by DIC Corporation) or an anti-fog film (AF-CV2C, 30 μm, manufactured by Futamura Chemical Co., Ltd.) that had undergone corona discharge treatment was printed using a gravure proofing press with an etching plate depth of 30 microns (drying temperature 50°C, printing speed 50 m / min) to obtain printed materials.

[0098] Polypropylene film prints and anti-fog film prints were obtained in the same manner as described above, except that the gravure printing inks obtained in Examples 2-17, Examples 35-51, Comparative Examples 1-7, and Comparative Examples 15-21 were used.

[0099] The gravure printing ink obtained in Example 18 was diluted with a diluent solvent (n-propyl acetate:ethyl acetate:isopropyl alcohol:methylcyclohexane = 20:20:20:40 (mass ratio)), adjusted to 15 seconds in a Zahn cup No. 3, and used as a diluted ink for printing. Next, a polypropylene film (D-SHNY01, 28 μm, manufactured by DIC Corporation) or an anti-fog film (AF-CV2C, 30 μm, manufactured by Futamura Chemical Co., Ltd.) that had undergone corona discharge treatment was printed using a gravure proofing press with an etching plate depth of 30 microns (drying temperature 50°C, printing speed 50 m / min) to obtain printed materials.

[0100] Polypropylene film prints and anti-fog film prints were obtained in the same manner as described above, except that the gravure printing inks obtained in Examples 19-34 and Comparative Examples 8-14 were used.

[0101] The gravure printing inks and printed materials obtained in Examples 1-51 and Comparative Examples 1-21 were evaluated as described below. The results are shown in Tables 1-4.

[0102] <Adhesiveness> Adhesion was evaluated by the degree to which the ink coating peeled off the polypropylene film printed in Examples 1-51 and Comparative Examples 1-21 when adhesive tape (product name: cellophane tape) was applied to the ink coating surface and rapidly peeled off. The evaluation was performed after the prints were left to stand at 25°C for 24 hours after printing. A. The ink layer is not removed from the film. B. Products in which less than 5% of the ink layer has been peeled from the film. C. Products in which the area peeled from the ink layer film is 5% or more but less than 15%. D. Cases where the area peeled from the ink layer film is 15% or more but less than 50%. E. Products in which 50% or more of the ink layer has been peeled off from the film. Furthermore, A, B, and C are within a range that does not pose any practical problems.

[0103] <PVC blocking resistance> The printed materials printed on the polypropylene films of Examples 1-51 and Comparative Examples 1-21 were cut into 4cm squares, and the ink-coated surface of the printed material was placed on top of a soft polyvinyl chloride sheet cut to the same size, and a load of 0.5kg / cm² was applied. 2After applying a load and leaving it in a 50°C / 80%RH atmosphere for 24 hours, the printed surface and the vinyl chloride sheet were peeled apart, and the PVC blocking resistance was evaluated based on the degree of ink film peeling. A. The ink layer is not removed from the film. B. Products in which less than 5% of the ink layer has been peeled from the film. C. Products in which the area peeled from the ink layer film is 5% or more but less than 15%. D. Cases where the area peeled from the ink layer film is 15% or more but less than 50%. E. Products in which 50% or more of the ink layer has been peeled off from the film. Furthermore, A, B, and C are within a range that does not pose any practical problems.

[0104] <Anti-fog film blocking properties> The gravure prints printed on the anti-fog films of Examples 1-51 and Comparative Examples 1-21 were printed at a density of 40 kg / cm². 2 The printed material was wound up under a load, left in a 50°C atmosphere for 24 hours, and then the printed and unprinted sides of the wound material were separated. The degree of ink peeling was used to evaluate the blocking resistance. A. The ink layer is not removed from the film. B. Products in which less than 5% of the ink layer has been peeled from the film. C. Products in which the area peeled from the ink layer film is 5% or more but less than 15%. D. Cases where the area peeled from the ink layer film is 15% or more but less than 50%. E. Products in which 50% or more of the ink layer has been peeled off from the film. Furthermore, A, B, and C are within a range that does not pose any practical problems.

[0105] <Abrasion resistance> The ink layer surface of each gravure print printed on polypropylene film in Examples 1-51 and Comparative Examples 1-21 was placed on high-quality paper and evaluated using a Japan Society for the Promotion of Science (JSPS) type friction resistance tester. The evaluation conditions were a load of 500g × 100 cycles of friction, and the degree to which the ink layer peeled off from the film after friction was evaluated. A. Those in which less than 5% of the ink layer has been peeled from the film. B. Products in which the area peeled from the ink layer film is 5% or more but less than 15%. C. Products in which the area peeled from the ink layer film is 15% or more but less than 25%. D. Cases where the area peeled from the ink layer film is 25% or more but less than 50%. E. Products in which 50% or more of the ink layer has been peeled off from the film. Furthermore, A, B, and C are within a range that does not pose any practical problems.

[0106] <Heat resistance> The glossy side of aluminum foil was applied to the ink layer surface of each gravure print printed on polypropylene film in Examples 1-51 and Comparative Examples 1-21, and evaluated using a heat seal tester. The evaluation conditions were a temperature of 170°C, a load of 2 kg, and a pressing time of 1 second. Heat resistance was evaluated based on the degree to which the ink layer adhered to the aluminum foil after pressing. A. Those in which the area of ​​the ink layer adhering to the aluminum foil is less than 5%. B. Those in which the area of ​​the ink layer attached to the aluminum foil is 5% or more but less than 15%. C. The area of ​​the ink layer adhering to the aluminum foil is 15% or more but less than 25%. D. The area of ​​the ink layer adhering to the aluminum foil is 25% or more but less than 50%. E. The ink layer has an adhesion area of ​​50% or more to the aluminum foil. Furthermore, A, B, and C are within a range that does not pose any practical problems.

[0107] <Oil resistance> Each gravure print printed on polypropylene film from Examples 1-51 and Comparative Examples 1-21 was cut to a size of 2 cm x 20 cm. Melted commercially available butter (Snow Brand Hokkaido Butter, manufactured by Snow Brand Megmilk Co., Ltd.) was applied to the entire surface of the ink layer, and after standing for 12 hours at 25°C, a cloth (Kanakin No. 3) was applied and evaluated using a Japan Society for the Promotion of Science (JSPS) type friction resistance tester. The evaluation conditions were a load of 200 g x 100 back-and-forth friction cycles, and oil resistance was evaluated from the degree to which the ink layer peeled off from the film after friction. A. Those in which less than 5% of the ink layer has been peeled from the film. B. Products in which the area peeled from the ink layer film is 5% or more but less than 15%. C. Products in which the area peeled from the ink layer film is 15% or more but less than 25%. D. Cases where the area peeled from the ink layer film is 25% or more but less than 50%. E. Products in which 50% or more of the ink layer has been peeled off from the film. Furthermore, A, B, and C are within a range that does not pose any practical problems.

[0108] <Printability> For the gravure printing inks obtained in Examples 1-51 and Comparative Examples 1-21, the viscosity was adjusted to 15 seconds (25°C) using a Zahn cup No. 3 with a diluting solvent (for Examples 1-17, Examples 35-51, Comparative Examples 1-7 and 15-21, n-propyl acetate:ethyl acetate:isopropyl alcohol:methylcyclohexane = 35:30:20:15 (mass ratio); for Examples 18-34 and Comparative Examples 8-14, n-propyl acetate:ethyl acetate:isopropyl alcohol:methylcyclohexane = 20:20:20:40 (mass ratio)). The area of ​​the plate overprint was visually determined and evaluated after 90 minutes of idle rotation of the printing plate on the printing press. A. The area of ​​the print cover cannot be visually confirmed. B. Those with a plate overlap area of ​​0% or more but less than 5% C. Those with a plate cover area of ​​5% or more but less than 10%. D. Those with a plate cover area of ​​10% or more but less than 20% E. Those with a plate overlap area of ​​20% or more. Furthermore, A, B, and C are within a range that does not pose any practical problems.

[0109] <Leveling properties> The leveling properties were evaluated using gravure printed materials printed on polypropylene films from Examples 1-51 and Comparative Examples 1-21. The evaluation was performed visually on 100% (solid) areas, and the evaluation criteria were as follows. (Evaluation Criteria) A. No irregular variations in density or pinhole-like defects are observed; a uniform film is formed. B. Some irregular variations in shading are observed, but no pinhole-like defects are found. C. Irregular variations in shading are observed, and slight pinhole-like defects are present. D. Pinhole-like defects are observed. E. Pinhole-like defects are observed everywhere. Furthermore, A, B, and C are within a range that does not pose any practical problems.

[0110] When evaluating the adhesion, PVC blocking resistance, abrasion resistance, heat resistance, and oil resistance of the anti-fogging film printed materials obtained in Examples 1-51 and Comparative Examples 1-21, the same evaluation results as those obtained for polypropylene film printed materials were obtained.

[0111] In particular, the gravure printing ink of the present invention has a film blocking resistance to fogging of printed materials of 40 kg / cm². 2 It demonstrated a unique effect, showing good performance even under harsh conditions such as winding the printed material under a load and leaving the wound material in a 50°C atmosphere for 24 hours.

[0112] The present invention provides a gravure printing ink that exhibits good storage stability, abrasion resistance, heat resistance, oil resistance, and printability, and in particular, excellent adhesion to the substrate, resistance to blocking on vinyl chloride sheets, and resistance to blocking on anti-fogging films when printed and wound up. Comparative Examples 1 and 2, which combined polyurethane resin and vinyl chloride resin and did not contain either resin, Comparative Examples 8 and 9, which combined polyamide resin and cellulose resin and did not contain either resin, Comparative Examples 15 and 16, which combined polyurethane resin and cellulose resin and did not contain either resin, Comparative Examples 3-5, 10-12, and 17-19, which did not contain bisamide, and Comparative Examples 6, 7, 13, 14, 20, and 21, which did not use titanium chelate in combination, all failed to meet the criteria.

Claims

1. A gravure printing ink for surface printing containing a pigment, a binder resin, a bisamide, a chelating agent, and an organic solvent, The binder resin contains two types of resins, consisting of a combination of polyurethane resin and vinyl chloride resin, a combination of polyamide resin and cellulose resin, or a combination of polyurethane resin and cellulose resin. The chelating agent includes acetylacetone-based titanium chelate and alkyl acetoacetate-based titanium chelate. The molecular weight of the bisamide is 600 to 2,000. The bisamide is represented by the following general formula (1) or general formula (2): General formula (1) R 1 -CONH-R 2 -HNCO-R 3 General formula (2) R 4 -NHCO-R 5 -CONH-R 6 (In the formula, R1, R3, R4, and R6 represent aliphatic hydrocarbon groups having 10 to 25 carbon atoms, and may be the same or different; R2 and R5 represent alkylene groups or arylene groups.) The mass ratio of the bisamide to the acetylacetone-based titanium chelate and the alkyl acetoacetate-based titanium chelate (total amount of bisamide / acetylacetone-based titanium chelate and alkyl acetoacetate-based titanium chelate) is 10:90 to 90:

10. Gravure printing ink for surface printing.

2. The gravure printing ink for surface printing according to claim 1, wherein the bisamide content is 0.1 to 5% by mass of the total mass of the printing ink.

3. The gravure printing ink for surface printing according to claim 1 or 2, wherein the bisamide has an unsaturated hydrocarbon group.

4. The gravure printing ink for surface printing according to claim 1 or 2, wherein the chelating agent content is 0.1 to 5% by mass of the total mass of the printing ink.

5. Furthermore, the gravure printing ink for surface printing according to claim 1 or 2, further comprising hydrocarbon wax particles.

6. Furthermore, the gravure printing ink for surface printing according to claim 1 or 2 contains an antifoaming agent.

7. A printed article having a printed layer on a substrate made of the gravure printing ink for surface printing described in claim 1 or 2.

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