Method for manufacturing gravure or flexographic inks, printed materials, and laminates.

Abstract

The present invention aims to provide a method for manufacturing printed materials that satisfies all requirements of trapping properties, long-run suitability, blocking resistance, and laminate strength. [Solution] A method for producing gravure or flexographic ink comprising a pigment, a binder resin, a hydrocarbon wax, and an organic solvent, comprising a dispersion step of mill-dispersing the hydrocarbon wax in the presence of the organic solvent to adjust the average particle size (D50) of the hydrocarbon wax in the particle size distribution to 4 μm to 20 μm.

Description

Technical Field

[0001] The present invention relates to a method for producing gravure or flexographic ink, printed matter, and a laminate.

Background Art

[0002] Gravure or flexographic inks are widely used for the purpose of imparting cosmetic and functional properties to paper or plastic substrates. When the ink is used for packaging materials, especially packages such as food packaging, after printing the ink on a substrate such as a plastic film to obtain printed matter, the obtained printed matter is laminated with another plastic film to obtain a laminated packaging material. Since the substrates such as plastic films and the laminate structure are appropriately selected from various types according to the contents of the package and the purpose of use, gravure or flexographic inks having good physical properties are required regardless of the type of substrate.

[0003] Physical properties required for laminating ink include printing suitability such as plate fouling property and printing stain property, and printing effects such as adhesion to the film and blocking resistance. Since gravure printing and flexographic printing are methods of winding up printed matter, high pressure is applied inside the wound-up printed matter, causing blocking where the ink migrates to the overlapping substrates. In surface printing applications, it is known to improve blocking by using a wax component. However, when a wax component is used in laminating ink, concerns such as poor laminate appearance, insufficient laminate strength, and trapping property arise. Therefore, there are few examples of using a wax component in laminating ink.

[0004] In Patent Document 1, by applying a fatty acid amide or a hydrocarbon wax to a gravure ink for lamination containing a polyurethane resin and a terpene phenol resin, plate fouling property, misting property, laminate strength, and blocking resistance are achieved. However, the particle size distribution and particle diameter of the hydrocarbon wax used are not described, and it is not shown whether the same effect is obtained in inks that do not use terpene phenol resin.

[0005] Furthermore, Patent Document 2 describes how blocking resistance, abrasion resistance, and retort resistance are achieved by applying a hydrocarbon wax with adjusted average particle size to a laminating ink containing polyurethane resin and a vinyl chloride / vinyl acetate copolymer or a vinyl chloride / acrylic copolymer. However, the method for adjusting the average particle size of the hydrocarbon wax is not described, and there is no mention of trapping properties or suitability for long runs.

[0006] Furthermore, Patent Document 3 describes an invention for a method of producing a wax dispersion liquid with uniform and fine particle size, which is used as a wax dispersion liquid to be added to gravure ink. This method involves dispersing wax in an alcohol-based solvent at a liquid temperature of 40°C or lower. However, there are concerns regarding blocking resistance and lamination strength due to the extremely small particle size.

[0007] However, no gravure ink for lamination containing hydrocarbon wax has yet been invented that satisfies all of the following requirements for trapping properties, long-run suitability, blocking resistance, and lamination strength when used to produce printed materials or laminates. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2018-053014 [Patent Document 2] Patent No. 7346795 [Patent Document 3] Japanese Patent Application Publication No. 6-277879 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] The objective of this invention is to provide a method for manufacturing printed materials that achieves a balance of trapping properties, long-run suitability, blocking resistance, and lamination strength. [Means for solving the problem]

[0010] As a result of diligent research into the aforementioned problems, the inventors have found that all of the aforementioned problems can be solved by the manufacturing method described below, and have thus come to the present invention.

[0011] A method for producing gravure or flexographic ink, comprising a pigment, a binder resin, a hydrocarbon wax, and an organic solvent, The present invention relates to a method for producing gravure or flexographic ink, comprising a dispersion step of mill-dispersing the hydrocarbon wax in the presence of the organic solvent to adjust the average particle size (D50) of the hydrocarbon wax to 4 μm to 20 μm.

[0012] The present invention relates to a method for producing gravure or flexographic ink, wherein the penetration degree of the hydrocarbon wax is 1 to 14.

[0013] The present invention relates to a method for producing gravure or flexographic ink, wherein the hydrocarbon wax is polyethylene wax and / or Fischer-Tropsch wax.

[0014] The present invention relates to a method for producing gravure or flexographic ink, wherein, in the dispersion process, the ratio (D80 / D50) of the particle size of the hydrocarbon wax with a cumulative frequency of 80% (D80) to the average particle size (D50) is 3.0 or less.

[0015] This invention relates to a method for producing gravure or flexographic ink, wherein, in the dispersion step, the particle size (D80) of the hydrocarbon wax with a cumulative frequency of 80% in the particle size distribution is 60 μm or less.

[0016] The present invention relates to a method for producing gravure or flexographic ink, wherein the binder resin contains a polyurethane resin.

[0017] The present invention relates to a method for producing gravure or flexographic ink, wherein the polyurethane resin contains structural units derived from polyester polyols, which are condensation reaction products of a dibasic acid and a diol.

[0018] The present invention relates to a method for producing the gravure or flexographic ink, wherein the binder resin contains a vinyl chloride copolymer resin and / or a cellulose-based resin.

[0019] The present invention relates to a method for producing the gravure or flexographic ink, wherein the organic solvent contains an ester-based organic solvent and / or an alcohol-based organic solvent.

[0020] The present invention relates to a method for producing a printed matter, comprising a step 1 of producing an ink by the method for producing the gravure or flexographic ink, and a step 2 of printing the ink on a substrate 1 after step 1.

[0021] The present invention relates to a method for producing a laminate, comprising a step 1 of producing an ink by the method for producing the gravure or flexographic ink, a step 2 of producing a printed matter by printing the ink on a substrate 1 after step 1, and a step 3 of laminating a substrate 2 on the printed matter after step 2. [Effect of the Invention]

[0022] According to the present invention, it has become possible to provide a method for producing a printed matter having trapping properties, long-run suitability, antiblocking properties, and laminate strength. [Embodiments for Carrying Out the Invention]

[0023] 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.

[0024] Hereafter, gravure or flexographic ink may be simply abbreviated as "ink," but they are synonymous. Also, in this specification, "D50" refers to the particle size at a cumulative frequency of 50% determined from particle size distribution measurement, and may also be called the average particle size. Also, in this specification, "D80" refers to the particle size at a cumulative frequency of 80% determined similarly from particle size distribution measurement. Printed materials obtained by printing with gravure or flexographic ink may be simply abbreviated as "printed material," but they are synonymous. In this specification, "solids" refers to the total mass of non-volatile components in the total mass of gravure or flexographic ink.

[0025] The present invention relates to a method for producing gravure or flexographic ink, comprising a pigment, a binder resin, a hydrocarbon wax, and an organic solvent. By including the hydrocarbon wax, which has undergone a process of adjusting the D50 to 4-20 μm by mill dispersion in the presence of the organic solvent, the long-term stability of the finished ink is improved, and the trapping properties are enhanced by improving the wetting spread of the ink on the film. Furthermore, good printability can be maintained even during long printing periods, improving long-run suitability. In addition, by adjusting the D80 / D50 to 3.0 or less, a good dispersion state with less aggregation is achieved, further improving the stability of the finished ink. It should be noted that this consideration is based solely on speculation and does not limit the invention in any way.

[0026] This invention will be explained in the following manufacturing steps. Step 1) A step of manufacturing ink by a gravure or flexographic ink manufacturing method. Step 2) A step of printing the ink obtained in Step 1 onto the substrate 1 to manufacture a printed material. Step 3) A step of manufacturing a laminate by laminating the substrate 2 onto the printed material obtained in Step 2.

[0027] (Gravure or flexographic ink) The gravure or flexographic ink of the present invention comprises a pigment, a binder resin, a hydrocarbon wax, and an organic solvent. Furthermore, 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 may be suitably included as needed. Gravure ink is preferred to obtain the effects of the present invention to the fullest extent.

[0028] (Pigment) The gravure or flexographic ink in this invention preferably contains a pigment as a coloring agent, and the use of inorganic or organic pigments is preferred. The CI pigments listed in the color index can be used as appropriate. Examples of inorganic pigments include titanium dioxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, aluminum hydroxide, chromium oxide, silica, carbon black, aluminum, and mica. Titanium dioxide is preferred as a white pigment in terms of coloring power, opacity, chemical resistance, and weather resistance, and titanium dioxide with a basic pigment surface is even more preferred. Aluminum is available in powder or paste form, but it is preferred to use it in paste form for ease of handling and safety, and it can be either leafing or non-leafing. Barium sulfate, calcium carbonate, and aluminum hydroxide are called extender pigments and are used as fillers to improve fluidity, strength, and optical properties. 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, dianthraquinone pigments, anthrapyrimidine pigments, perylene pigments, perinone pigments, quinacridone pigments, thioindigo pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, azomethine azo pigments, flavanthrone pigments, diketopyrrolopyrrole pigments, isoindoline pigments, indanthrone pigments, and carbon black pigments. Other examples 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, and those listed in the color index can be used in combination as needed.

[0029] The pigment is preferably included in an amount sufficient to ensure the ink's concentration and coloring power, i.e., in a ratio of 1 to 50% by mass relative to the total mass of the printing ink, and more preferably in a ratio of 3 to 25% by mass.

[0030] (Binder resin) The binder resin used in the present invention preferably contains a polyurethane resin. The binder resin in the present invention refers to the binding resin and is preferably a thermoplastic resin soluble in organic solvents. Furthermore, the content of the binder resin in the total solids mass is preferably 20 to 80% by mass, more preferably 25 to 75% by mass, and even more preferably 30 to 70% by mass.

[0031] (Polyurethane resin) The polyurethane resin used in this invention preferably contains structural units derived from polyester polyols, which are condensation reaction products of dibasic acids and diols. The content of dibasic acid-derived structural units is preferably 8% by mass or more, more preferably 10% by mass or more, and even more preferably 13% by mass or more, based on the total mass of the polyurethane resin. Furthermore, the content of dibasic acid-derived structural units is preferably 30% by mass or more, more preferably 35% by mass or more, and even more preferably 40% by mass or more, based on the total mass of polyols constituting the polyurethane resin. This is because a coating film with a balanced combination of flexibility and toughness is formed, improving the laminate strength. The polyurethane resin is preferably a polyurethane resin obtained by a condensation reaction between a polyol and a polyisocyanate, or a polyurethane resin (urethane urea resin) obtained by a reaction (called chain extension) between a urethane prepolymer having isocyanate groups at the ends, which is a condensation reaction product of a polyol and a polyisocyanate, and a polyamine. It is particularly preferable that the polyol contains a high molecular weight polyol. Using a polyurethane resin has a significant effect on substrate adhesion, long-run suitability, blocking resistance, and laminate strength.

[0032] In the present invention, multiple types of polyurethane resins may be used in combination. The total content of polyurethane resin solids in the total solids of gravure or flexographic ink is preferably 15 to 65% by mass, more preferably 20 to 60% by mass, and even more preferably 25 to 55% by mass. The total content of polyurethane resin solids in the total solids of binder resin is preferably 20 to 100% by mass, more preferably 30 to 95% by mass, and even more preferably 50 to 90% by mass. Being within the above ranges results in good long-run suitability and blocking resistance. The weight-average molecular weight (Mw) of the polyurethane resin is preferably 10,000 to 200,000, more preferably 11,000 to 180,000, and even more preferably 12,000 to 150,000. Furthermore, the amine value of the polyurethane resin is preferably 1 to 20 mg KOH / g, more preferably 1.5 to 15 mg KOH / g, and even more preferably 1.7 to 10 mg KOH / g.

[0033] (Polyol) The polyol includes a polyester polyol containing dibasic acid-derived structural units, and it is more preferable that the weight-average molecular weight of the polyester polyol is 400 to 10,000. It is preferable that the total mass of the polyol contains 50% by mass or more of the polyester polyol, and more preferably 70% by mass or more. Furthermore, other polyols besides the polyester polyol may be used in combination. Examples of such polyols include polyether polyols, polycarbonate polyols, and polyolefin polyols. It is preferable that the polyol other than the polyester polyol is used in an amount of 50% by mass or less of the total mass of the polyol. Among polyols used in combination with the polyester polyol, polyether polyols are preferred, and among polyether polyols, polytrimethylene glycol, polytetramethylene glycol, polypropylene glycol, polyethylene glycol, and copolymers thereof are more preferred.

[0034] (Polyester polyol) The polyester polyol is preferably a condensation product of a dibasic acid and a diol. By using a polyester polyol, which is a condensation product of a dibasic acid and a diol, as the polyol, the polyurethane resin contains constituent units derived from the dibasic acid.

[0035] (Dibasic acid) Examples of dibasic acids include adipic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, oxalic acid, succinic acid, malonic acid, glutaric acid, dimer acid, pimelic acid, superiric acid, azelaic acid, trimellitic acid, pyromellitic acid, and others. In particular, the inclusion of sebacic acid and dimer acid is preferred. This improves laminate strength and blocking resistance.

[0036] (Diol) The diol constituting the above polyester polyol preferably includes both branched and linear diols. This results in a tough coating film for the polyurethane resin, improving blocking resistance and laminate strength. Here, a linear diol refers to a diol that does not have substituents such as branched alkyl groups, and suitable examples include alkylene glycol, dialkylene glycol, and trialkylene glycol. A branched diol refers to a diol in which at least one hydrogen atom of the hydrocarbon group of alkylene glycol is substituted with an atom other than hydrogen. Since linear diols impart crystallinity and branched diols impart flexibility, polyurethane resins using these form a well-balanced coating film, improving blocking resistance, long-run suitability, and laminate strength.

[0037] Suitable branched diols include 2-butyl-2-ethyl-1,3-propanediol (hereinafter also referred to as BEPG), 2-methyl-1,3-propanediol (hereinafter also referred to as MPO), 3-methyl-1,5-pentanediol (hereinafter also referred to as MPD), neopentyl glycol (hereinafter also referred to as NPG), 1,2-propylene glycol (hereinafter also referred to as PG), 2,4-diethyl-1,5-pentanediol, 1,3-butanediol, and dipropylene glycol. In the present invention, it is preferable to use at least one branched diol selected from MPO, MPD, BEPG, NPG, PG, and 2,4-diethyl-1,5-pentanediol, more preferably NPG and / or BEPG, and even more preferably NPG.

[0038] The linear diol is preferably an alkylene glycol, and suitable 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, with EG, 1,3-PD, 1,4-BD, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, and the like being preferred. Furthermore, from the viewpoint of blocking resistance, EG, 1,3-PD, and 1,4-BD are more preferred.

[0039] (Polyisocyanate) The polyisocyanate preferably contains a diisocyanate. Examples of such diisocyanates include aliphatic diisocyanates such as tetramethylene diisocyanate, isopropyl diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate. Alicyclic diisocyanates such as cyclohexane-1,4-diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate, and dimer diisocyanates obtained by converting the carboxyl group of a dimer acid to an isocyanate group; Examples include aromatic diisocyanates such as α,α,α',α'-tetramethylxylylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyli isocyanate, dimethyldiphenylmethane diisocyanate, tetramethyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, o-xylylene diisocyanate, and 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate. Among these, alicyclic or aromatic aliphatic diisocyanates are preferred from the viewpoint of ease of reaction control and a good balance of performance in the resulting polyurethane resin, and isophorone diisocyanate and α,α,α',α'-tetramethylxylylene diisocyanate are particularly preferred. At least one type of diisocyanate may be used, and two or more types can be used in combination.

[0040] (Polyamines) Diamines are preferred as polyamines, and suitable 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 suitably used. These diamines can be used individually or in combination of two or more, but isophoronediamine is preferred. Furthermore, it is also preferable to use polyamines having 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, in combination with the above-mentioned diamines.

[0041] (Other binder resins) In the present invention, it is also preferable to use other binder resins in combination with the binder resin. By using other binder resins in combination, the flexibility and toughness of the coating film can be controlled, and significant effects can be imparted to blocking resistance, long-run suitability, and laminate strength. Examples of such resins are not limited to the following, but can be preferably listed as cellulose resins, polyamide resins, vinyl chloride copolymer resins, rosin resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, acrylic resins, styrene resins, dammar resins, styrene-maleic acid copolymer resins, polyester resins, alkyd resins, terpene resins, phenol-modified terpene resins, ketone resins, cyclized rubbers, chlorinated rubbers, butyral, polyacetal resins, petroleum resins, and modified resins thereof. Among these, vinyl chloride copolymer resins and / or cellulose resins are preferred. Among vinyl chloride copolymer resins, vinyl chloride-vinyl acetate copolymer resins and vinyl chloride-acrylic copolymer resins are preferred. These resins can be used individually or in mixtures of two or more types.

[0042] In binder resins, the solid content mass ratio of polyurethane resin to other binder resins is preferably 99:1 to 15:85, more preferably 95:5 to 20:80, and even more preferably 85:15 to 30:70. This is because it improves blocking resistance, long-run suitability, and laminate strength.

[0043] (Vinyl chloride-vinyl acetate copolymer resin) The vinyl chloride-vinyl acetate copolymer resin has vinyl chloride units and vinyl acetate units. It is also preferable that it has vinyl alcohol units. The mass ratio of vinyl chloride units to vinyl acetate units (vinyl chloride units:vinyl acetate units) is preferably 98:2 to 70:30, and more preferably 95:5 to 80:20, from the viewpoint of improving the blocking resistance of the coating film and suppressing a decrease in adhesion to the support (substrate) film. The weight-average molecular weight is preferably 5,000 to 50,000, and more preferably 10,000 to 35,000. The content of vinyl chloride-vinyl acetate copolymer resin in the total solids of the gravure or flexographic ink is preferably 1 to 50% by mass, more preferably 3 to 45% by mass, and even more preferably 5 to 40% by mass.

[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 also preferably has a hydroxyl value of 20 to 200 mg KOH / g, and a glass transition temperature of 50°C to 90°C. The content of the vinyl chloride-acrylic copolymer resin in the total solids of the gravure or flexographic ink is preferably 1 to 50% by mass, more preferably 3 to 45% by mass, and even more preferably 5 to 40% by mass.

[0045] In the following explanation, (meth)acrylic and (meth)acrylate refer to methacrylic and acrylic, methacrylate and acrylate, respectively.

[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 and improve the storage stability of the ink. These can be used individually or in combination of two or more. Other acrylic monomers may be included as needed.

[0047] (Cellulose resin) Cellulose resins include, for example, acyl-substituted celluloses such as nitrocellulose, cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate; alkyl-substituted celluloses such as methylcellulose and ethylcellulose; and celluloses having hydroxyl groups such as benzylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, and hydroxymethylpropylcellulose. Nitrocellulose, acyl-substituted cellulose, and / or alkyl-substituted cellulose are particularly preferred. Furthermore, the degree of hydroxyl group substitution in the cellulose resin is preferably around 30-85%. At least one type of cellulose resin may be used, and two or more types can be used in combination.

[0048] The weight-average molecular weight of the cellulose resin is preferably 10,000 to 500,000. As the molecular weight increases, it becomes more difficult to dissolve in organic solvents and tends to become more viscous, thus limiting the content. Therefore, the weight-average molecular weight is more preferably 10,000 to 300,000, and even more preferably 10,000 to 100,000. The content of the cellulose resin in the total solids of the gravure or flexographic ink is preferably 1 to 50% by mass, more preferably 3 to 45% by mass, and even more preferably 5 to 40% by mass.

[0049] (Hydrogen-based wax) In this invention, the gravure or flexographic ink contains a hydrocarbon wax. Hydrocarbon waxes include natural waxes and synthetic waxes. Specifically, natural waxes include paraffin wax, microcrystalline wax, montane wax, carnauba wax, candelilla wax, rice wax, and wood wax. Synthetic waxes include polyethylene wax, polypropylene wax, Fischer-Tropsch wax, polytetrafluoroethylene wax, and amide wax. Polyethylene wax and Fischer-Tropsch wax are preferred from the viewpoint of blocking resistance and trapping properties. Furthermore, plate coverage in gravure printing is also improved. The penetration (hardness) of the hydrocarbon wax is preferably 1 to 14, more preferably 2 to 12, and even more preferably 4 to 8 (unit: 10). -1 (mm). This is because the trapping properties are further improved. Here, penetration refers to the value obtained according to JIS K2207. Furthermore, the hydrocarbon wax content is preferably 0.1% to 15% by mass as solid content of hydrocarbon wax in the total solid content of gravure or flexographic ink, more preferably 0.5% to 10% by mass, and even more preferably 1% to 8% by mass. This is because when the hydrocarbon wax content is within the above range, blocking resistance and long-run suitability are improved. Furthermore, the hydrocarbon wax has a density of 900 to 990 kg / m³ at 23°C as specified in JIS K7112 (Method B). 3Preferably, it is 920-990 kg / m 3 It is even more preferable that the melting point in DSC measurement is 90 to 150°C, and more preferably 100 to 130°C.

[0050] (Polyethylene wax) Polyethylene wax is classified into ethylene polymerized polyethylene and pyrolysis-type low-density polyethylene. Ethylene polymerized polyethylene is further divided into high-density polymerized polyethylene, low-density polymerized polyethylene, oxidized polyethylene, acid-modified polyethylene, and special monomer-modified polyethylene, and any of these types may be used, or they may be used in combination. Acid-modified polyethylene is preferably copolymerized with acidic monomers such as acrylic acid, methacrylic acid, maleic acid, and maleic anhydride during the polymerization of ethylene, and special monomer-modified polyethylene is preferably copolymerized with acrylic acid esters, styrene monomers, vinyl acetate, etc., during the polymerization of ethylene. In particular, it is preferable to include at least one selected from the group consisting of high-density polymerized polyethylene, low-density polymerized polyethylene, oxidized polyethylene, acid-modified polyethylene, and special monomer-modified polyethylene. It is also preferable for polyethylene wax to have an acid value. If it has an acid value, it is preferably 0.5 to 70 mg KOH / g. Furthermore, polyethylene wax with a molecular weight of 1000 to 8000 by viscosity method is particularly preferable, and a number-average molecular weight of 500 to 6000 determined by GPC measurement is preferable.

[0051] (Fischer-Tropsch Wax) Fischer-Tropsch wax is a wax produced using carbon monoxide and hydrogen as raw materials by the Fischer-Tropsch process, and has a nearly saturated, unbranched, linear molecular structure. Due to its linear structure, it has a high melting point, low viscosity, and hardness. Fischer-Tropsch wax exhibits extremely high thermal stability, showing almost no degradation even when exposed to heat for long periods. It is also preferable for Fischer-Tropsch wax to have an acid value. If it has an acid value, it is preferably 0.5 to 50 mg KOH / g. Furthermore, it is preferable that the number-average molecular weight of Fischer-Tropsch wax, as determined by GPC measurement, is 400 to 2000.

[0052] (Measurement of particle size) In this invention, the particle size of hydrocarbon waxes refers to the particle size measured by laser diffraction / scattering, which can be measured using, for example, the MT3300EXII manufactured by MicrotracMRB. In particular, in the particle size distribution of hydrocarbon waxes, the particle size at a cumulative frequency of 50% is described as D50 and the average particle size, and the particle size at a cumulative frequency of 80% is described as D80.

[0053] (Particle size of hydrocarbon waxes) From the viewpoint of solving the problems of the present invention, the average particle size (D50) of the hydrocarbon wax obtained by mill dispersion in the presence of an organic solvent is preferably 4 μm to 20 μm, more preferably 8 μm to 18 μm, and even more preferably 10 μm to 16 μm. By using a hydrocarbon wax with an average particle size (D50) of 4 to 20 μm, the trapping properties and long-run suitability of gravure or flexographic inks are improved. The particle size (D80) of hydrocarbon wax at a cumulative frequency of 80% obtained by mill dispersion in the presence of an organic solvent is preferably 60 μm or less, more preferably 55 μm or less, and even more preferably 50 μm or less. The particle size (D80) of hydrocarbon wax at a cumulative frequency of 80% is preferably 5 μm or more, more preferably 7 μm or more, and even more preferably 10 μm or more. When D80 is within the above range, the dispersion state of the gravure or flexographic ink is good, and the trapping properties and long-run suitability are improved. The ratio of the particle size at a cumulative frequency of 80% (D80) to the average particle size (D50) (D80 / D50), obtained by mill dispersion in the presence of an organic solvent, is preferably 3.0 or less, more preferably 2.8 or less, and even more preferably 2.5 or less. Furthermore, D80 / D50 is preferably 1.0 or more. When D80 / D50 is 3.0 or less, the gravure or flexographic ink dispersion state is good, and a uniform gravure or flexographic ink can be obtained.

[0054] (Dispersion process of hydrocarbon waxes) The present invention provides a method for producing gravure or flexographic ink, which includes a dispersion step of mill-dispersing a hydrocarbon wax in the presence of an organic solvent to adjust the average particle size (D50) in the particle size distribution to 4 to 20 μm. In this invention, mill dispersion refers to dispersion using a mill dispersion apparatus (also called a mill disperser) described later, and the same dispersion conditions as for conventional pigment dispersion can be used. For example, a hydrocarbon wax with an average particle size (D50) greater than 20 μm, an organic solvent, and other raw materials as needed are put into the mill disperser, and mill dispersion is started. Once dispersion has progressed to a certain extent, the average particle size (D50) of the hydrocarbon wax is checked by particle size distribution measurement, and if the target value has not been reached, dispersion is continued and the particle size distribution is measured again. By repeating this process until the average particle size (D50) reaches the target value, the average particle size (D50) of the hydrocarbon wax can be adjusted to 4 to 20 μm. Similarly, the ratio of the particle size at cumulative frequency of 80% (D80) to the average particle size (D50) (D80 / D50), and the particle size at cumulative frequency of 80% (D80), can be adjusted to the desired range by repeating mill dispersion and particle size distribution measurements until the target value is reached. Dispersion methods using a mill disperser include batch dispersion, path dispersion, and cyclic dispersion; any of these methods may be used, or two or more methods may be combined. Furthermore, the dispersion process of hydrocarbon waxes may be separate from the ink manufacturing process, or it may be carried out simultaneously with the ink manufacturing process.

[0055] (Organic solvent used in the dispersion process of hydrocarbon waxes) There are no particular restrictions on the organic solvent used in the dispersion process of hydrocarbon waxes; the information described for organic solvents included in gravure and flexographic inks can be applied. Ester-based organic solvents and alcohol-based organic solvents are preferred, and ester-based organic solvents are even more preferred. Among alcohol-based organic solvents, n-propanol and isopropyl alcohol are preferred, and among ester-based organic solvents, ethyl acetate and n-propyl acetate are preferred.

[0056] (Mill dispersion device) Examples of mill dispersion devices include dispersers, roller mills, ball mills, pebble mills, attritors, sand mills, and bead mills. Sand mills and bead mills, in particular, are preferred due to their high dispersibility. The media to be incorporated is not particularly limited, but steel beads and ceramic beads such as zirconia with a diameter of 0.2 to 4.0 mm are preferred. There are also no particular restrictions on operating conditions such as the amount of beads incorporated, rotation speed, and discharge rate.

[0057] (Organic solvents contained in gravure and flexographic inks) The gravure and flexographic inks of the present invention preferably contain an organic solvent as the main component of the liquid medium (50% by mass or more of the total medium). This is to improve printing performance. The organic solvent used is preferably a mixed solvent consisting of two or more organic solvents, and known organic solvents such as aromatic organic solvents, ketone organic solvents, ester organic solvents, alcohol organic solvents, and glycol ether solvents can be used. Among these, organic solvents that do not contain aromatic organic solvents such as toluene and xylene (non-toluene organic solvents) are more preferable. Even more preferable are organic solvents that do not contain aromatic organic solvents and / or ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone. The total mass content of the organic solvent is preferably 1 to 80% by mass of the total mass of the gravure or flexographic ink. In this invention, to improve printability, the organic solvent contained in the gravure and flexographic inks is preferably an ester-based organic solvent and / or an alcohol-based organic solvent. In particular, a mixed solvent of an ester-based organic solvent and an alcohol-based organic solvent is preferred. The preferred mass ratio of the ester-based organic solvent to the alcohol-based organic solvent (ester-based organic solvent / alcohol-based organic solvent) is 40 / 60 to 90 / 10.

[0058] (Ester-based organic solvents) Examples of ester-based organic solvents include ethyl acetate, n-propyl acetate, isopropyl acetate, and isobutyl acetate. Ethyl acetate and n-propyl acetate are particularly preferred, as they improve trapping properties. The content of the ester-based organic solvent is preferably 1 to 75% by mass of the total mass of the gravure or flexographic ink.

[0059] (Alcohol-based organic solvents) Examples of alcohol-based organic solvents include methanol, ethanol, n-propanol, isopropyl alcohol, and n-butanol. The content of the alcohol-based organic solvent is preferably 1 to 40% by mass of the total mass of the gravure or flexographic ink.

[0060] (Isocyanate-based curing agent) The gravure or flexographic ink of the present invention may contain a curing agent, and more preferably contains an isocyanate-based curing agent. This is to impart a crosslinked structure to the printed material using the isocyanate-based curing agent, thereby improving the laminate properties. If the binder resin is a polyurethane resin containing structural units derived from polyester polyol and has hydroxyl groups, amino groups, or other active hydrogen groups, the laminate strength is improved by crosslinking with these active hydrogen groups, or by self-crosslinking with the isocyanate-based curing agent alone if it does not have such active hydrogen groups.

[0061] The following describes preferred embodiments of the isocyanate-based curing agent. The weight-average molecular weight of the isocyanate-based curing agent is preferably 800 to 8000, more preferably 1000 to 4500, and even more preferably 1500 to 4000.

[0062] Suitable isocyanates include polyisocyanates containing adduct-type polyisocyanates (adduct form), biuret-type polyisocyanates (biuret form), isocyanurate-type polyisocyanates (isocyanurate form), and bifunctional polyisocyanates. Examples of adduct-type polyisocyanates, biuret-type polyisocyanates, and isocyanurate-type polyisocyanates include adduct-type polyisocyanates obtained from the reaction of trimethylolpropane or other polyols with diisocyanates, biuret-type polyisocyanates obtained by dimerization of diisocyanates linked by biuret bonds, and isocyanurate-type polyisocyanates obtained from the cyclic trimerization reaction of diisocyanates. The diisocyanate may be any of the above-mentioned diisocyanates, and among them, tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), hydrogenated diphenylmethane diisocyanate (hydrogenated MDI), hexamethylene diisocyanate (HDI), isophorone diisocyanate, xylylene diisocyanate (XDI), hydrogenated xylylene diisocyanate (hydrogenated XDI), etc. Adduct-type polyisocyanates, biuret-type polyisocyanates, and isocyanurate-type polyisocyanates may be used in combination, and may also be used in combination with other polyisocyanates.

[0063] Furthermore, the mass ratio of the polyester polyurethane resin to the isocyanate curing agent is preferably 99:1 to 60:40, more preferably 98:2 to 65:35, and even more preferably 95:5 to 70:30. This is because, within this range, the effects of crosslinking and adhesion to the substrate are good, and it is believed that sufficient effects are achieved in terms of laminate strength.

[0064] <Process 1> <Process for manufacturing gravure or flexographic ink> In the process for manufacturing gravure or flexographic inks of the present invention, ink can be manufactured by dissolving and / or dispersing raw materials in an organic solvent. Specifically, for example, a pigment dispersion can be manufactured by mixing and dispersing a pigment, polyurethane resin, organic solvent, and other raw materials such as other binder resins and additives as needed. Gravure or flexographic ink can then be manufactured by further blending a polyurethane resin and other binder resins and additives as needed into the obtained pigment dispersion. As a disperser, commonly used mill dispersers described in the (Mill Dispersion Equipment) section, such as roller mills, ball mills, pebble mills, attritors, sand mills, etc., can be used. In the present invention, hydrocarbon wax may be used by adding a wax dispersion liquid, prepared in advance by mill dispersion, to gravure or flexographic ink manufactured without hydrocarbon wax during printing, or it may be used as one of the raw materials in the gravure or flexographic ink manufacturing process.

[0065] <Process 2> <Process of printing gravure or flexographic ink onto substrate 1> In the process of printing gravure or flexographic ink according to the present invention, the ink obtained in step 1 is printed onto a substrate 1 using a gravure printing method or a flexographic printing method, thereby enabling the production of a suitable printed material.

[0066] (Base material 1) The substrates to which this invention can be applied are not limited to plastic substrates, paper substrates, metals, etc. Examples of plastic substrates include polyamide resins such as nylon 6, nylon 66, and nylon 46 (Ny), polyester resins such as polyethylene phthalate (PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate, biodegradable resins such as polyhydroxycarboxylic acids like polylactic acid, aliphatic polyester resins such as polyethylene succinate and polybutylene succinate, cellulose resins such as diacetylcellulose and triacetylcellulose, polyolefin resins such as polypropylene (PP) and polyethylene, polyimide resins, polyarylate resins, or mixtures thereof. Among these, films made of polyester, polyamide, and polypropylene are particularly suitable. These films may be unstretched or stretched films, and their manufacturing methods are not limited. The thickness of the substrate is also not particularly limited, but is usually in the range of 1 to 500 μm.

[0067] (Gravure version) In the gravure printing described above, 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 and laser, and they can be set as desired according to the design.

[0068] (Gravure printing machine) In a gravure printing press, each printing unit is equipped with the above-mentioned gravure plate and doctor blade, and a fussier roll can be used for the gravure plate as needed. There are multiple printing units, and each unit has an oven drying unit. The drying temperature is preferably around 35 to 70°C. Printing is performed by rotary printing using a roll printing method. The type of plate and doctor blade can be selected as appropriate, according to the specifications.

[0069] (Flexographic version) The plates used for the above flexographic printing include photosensitive resin plates that utilize UV ​​curing with 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 screen ruling of 75 lpi or higher is used. Any type of sleeve or cushioning tape can be used to attach the plate.

[0070] (Flexographic printing press) Flexographic printing presses include CI-type multi-color flexographic printing presses and unit-type multi-color flexographic printing presses. Ink supply methods include chamber type and two-roll type, and the appropriate printing press can be used.

[0071] <Process 3> <Step of laminating substrate 2 onto a gravure or flexographic ink printed material> In the process of laminating a substrate 2 onto a gravure or flexographic ink printed material of the present invention, an adhesive layer is further provided on the printed ink surface obtained by printing printing ink on a substrate 1, and the substrate 2 is bonded (laminated) to produce a laminate. Here, the substrate 2 may be the same as or different from the substrate 1. Typical examples of lamination processes include extrusion lamination, dry lamination, and non-solvent lamination. Extrusion lamination is a method in which an anchor coating agent is applied to the printing ink layer of a printed material, and molten polyethylene resin, molten polypropylene resin, etc., is extruded onto it, simultaneously bonding it to the substrate and creating a laminate. Dry lamination and non-solvent lamination are methods in which an adhesive is applied to the printing ink layer of a printed material, dried, and then heat-pressed onto a sealant to create a laminate. The difference between dry lamination and non-solvent lamination is whether or not they contain organic solvents or other volatile media.

[0072] (adhesive layer) The adhesive layer can be made from molten polyethylene resin, molten polypropylene resin, a urethane adhesive, an acrylic adhesive, or an anchor coat layer. Among these, an adhesive layer made from molten polyethylene resin is preferred. As the urethane adhesive, a two-component adhesive consisting of a mixture of polyol and isocyanate curing agent is preferred, with polyester-based and polyether-based polyols being examples. Specifically, examples include TM-250HV / CAT-RT86L-60, TM-550 / CAT-RT37, and TM-314 / CAT-14B manufactured by Toyo Morton Co., Ltd.

[0073] (Base material 2) Substrate 2 can be the same as that of substrate 1, and may be the same or different. It is preferable that it be a thermoplastic substrate (sometimes referred to as a sealant), and unoriented polyethylene substrates, unoriented polypropylene substrates, unoriented polyester substrates, etc., are preferred. [Examples]

[0074] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way to these examples unless it exceeds the essence of the invention. In the present invention, parts and % refer to parts by mass and mass %, respectively, unless otherwise noted.

[0075] (Measurement methods for various measurement parameters)

[0076] (Amine value) The amine value was determined according to JIS K0070, using the following method, which is the same amount of potassium hydroxide (mg) as the equivalent amount of hydrochloric acid 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: S g). 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 a 0.2 mol / L ethanolic hydrochloric acid solution (titer: f). The endpoint was defined as the point where the solution color changed from green to yellow, and the titration volume (A mL) at this point was used to determine the amine value using the following formula (Equation 1). (Equation 1) Amine value = (A × f × 0.2 × 56.108) / S [mgKOH / g]

[0077] (Weight average molecular weight Mw) The weight-average molecular weight (Mw) was determined by measuring the molecular weight distribution using a GPC (gel permeation chromatography) instrument (HLC-8220, manufactured by Tosoh Corporation) and calculating the converted molecular weight using polystyrene as the standard substance. The measurement conditions are shown below. Columns: The following columns were used, connected in series. TSKgelSuperAW2500 manufactured by Tosoh Corporation TSKgel SuperAW3000 manufactured by Tosoh Corporation TSKgel SuperAW4000 manufactured by Tosoh Corporation TSKgelguard Column Super AWH manufactured by Tosoh Corporation Detector: RI (Differential Refractometer) Measurement conditions: Column temperature 40°C Eluent: Tetrahydrofuran Flow rate: 1.0mL / min

[0078] (Particle size distribution of hydrocarbon waxes (D50, D80)) The particle size distribution (D50, D80) of hydrocarbon waxes was measured using a MicrotracMRB MT3300EXII particle size analyzer, and the particle size at a cumulative frequency of 50% (D50) and 80% (D80) was determined. The measurement conditions are shown below. Particle permeability: transparent Particle shape: non-spherical

[0079] (Synthesis Example 1) (Synthesis of Polyester Polyurethane Resin Solution) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 30.4 parts by mass of polyester polyol PO1 (a condensate of 1,3-PD:NPG:SeA = 1:1:4 (mass ratio) dissolved in ethyl acetate solids with 73.5% solid content, number average molecular weight 3000), 0.1 parts by mass of 1,3-PD, 3.7 parts by mass of isophorone diisocyanate (hereinafter abbreviated as IPDI), and 0.01 parts by mass of catalyst (stannous ethylhexylate 2) were charged. The mixture was reacted at 90°C for 3 hours under a nitrogen stream, 1.1 parts by mass of ethyl acetate and 6.5 parts by mass of n-propyl acetate were added, and the mixture was cooled to obtain a solution of the terminal isocyanate prepolymer. Next, to a solution prepared by mixing 1.6 parts by mass of isophorone diamine (hereinafter also abbreviated as IPDA), 0.2 parts of dibutylamine (hereinafter also abbreviated as DBA), 21.2 parts of ethyl acetate, 6.5 parts of n-propyl acetate, and 28.7 parts of isopropyl alcohol, the entire amount of the terminal isocyanate prepolymer solution obtained above was gradually added at room temperature, and then the mixture was reacted at 40°C for 1 hour to obtain a polyester polyurethane resin solution (solid content 28% by mass, weight-average molecular weight Mw 60000).

[0080] (Synthesis Example 2) (Synthesis of Polyether Polyurethane Resin Solution) In a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 22.4 parts by mass of polypropylene glycol (hereinafter abbreviated as PPG, number average molecular weight 3000), 8 parts by mass of ethyl acetate, 0.1 parts by mass of 1,3-PD, 3.7 parts by mass of IPDI, and 0.01 parts by mass of catalyst (stannous ethylhexyl 2-ethylhexylate) were charged. The mixture was reacted at 90°C for 3 hours under a nitrogen stream, 1.1 parts by mass of ethyl acetate and 6.5 parts by mass of n-propyl acetate were added, and the mixture was cooled to obtain a solution of the terminal isocyanate prepolymer. Next, the entire amount of the obtained terminal isocyanate prepolymer solution was gradually added at room temperature to a solution prepared by mixing 1.6 parts by mass of IPDA, 0.2 parts of DBA, 21.2 parts of ethyl acetate, 6.5 parts of n-propyl acetate, and 28.7 parts of isopropyl alcohol. The mixture was then reacted at 40°C for 1 hour to obtain a polyether polyurethane resin solution (solid content 28% by mass, weight-average molecular weight Mw 60000).

[0081] (Preparation Example 1) (Preparation of Wax Dispersion A1) Five parts by mass of wax (paraffin wax, product name: Paraffin Wax-125, manufactured by Nippon Seiro Co., Ltd.), 2.5 parts by mass of ethyl acetate, and 2.5 parts by mass of isopropanol were charged into a sand mill disperser (media: glass beads, particle size 0.8 mm) and dispersed by circulation. The particle size distribution was measured every 20 minutes, and the dispersion was stopped when the average particle size (D50) reached 7 μm and D80 reached 20 μm, to obtain wax dispersion A1 (solid content 50% by mass).

[0082] (Preparation Examples 2-18, Comparative Preparation Examples 1-3) (Preparation of wax dispersions A2-A18 and comparative wax dispersions B1-B3) Using the raw materials and dispersion method listed in Table 1, wax dispersions A2-A18 and comparative wax dispersions B1-B3 were obtained using the same procedure as in Preparation Example 1, with average particle sizes (D50) and D80 being the values ​​listed in Table 1. The amount of each raw material used was the same as in Preparation Example 1. The waxes used as raw materials and the dispersion conditions are described below. • Wax (Mitsui Chemicals, Ltd. Low-density polyethylene wax, product name 210P) • Wax (Mitsui Chemicals, Ltd., slightly acidic polyethylene wax, product name 220MP) • Wax (Mitsui Chemicals, Ltd. Low-density polyethylene wax, product name 320P) • Wax (Mitsui Chemicals, Ltd., slightly acidic polyethylene wax, product name 310MP) • Wax (High-density polyethylene wax, product name 400P, manufactured by Mitsui Chemicals, Inc.) • Wax (Mitsui Chemicals, Ltd., slightly acidic polyethylene wax, product name 320MP) • Wax (Manufactured by Micro Powder, Fischer-Tropsch Wax, Product Name MP-22C) • Wax (Mitsui Chemicals, Ltd., Polypropylene Wax, Product Name NP055) • Preparation Example 10: The raw materials listed in Table 1 were loaded into a sand mill disperser under the same conditions as in Preparation Example 1 and prepared by pass dispersion. • Comparative preparation example 3: The raw materials listed in Table 1 were placed in a container and mixed with a spatula without milling.

[0083] [Table 1]

[0084] [Example 1] (Manufacturing of gravure ink S1) Gravure ink S1 was prepared by stirring and mixing 10 parts by mass of pigment (manufactured by Toyo Color Co., Ltd., product name LIONOL BLUE FG-7358-G), 16 parts by mass of polyester polyurethane resin solution, 12 parts by mass of vinyl chloride-vinyl acetate copolymer resin solution (manufactured by Nisshin Chemical Industry Co., Ltd., product name Solvine TA5R, solid content 24% by mass), and 18 parts by mass of mixed solvent. After dispersion using a bead mill (sand mill), 6 parts by mass of wax dispersion A1, 20 parts by mass of polyester polyurethane resin solution, and 18 parts by mass of mixed solvent were added and stirred and mixed. The mixed solvent was a mixture of n-propyl acetate, ethyl acetate, isopropyl alcohol, and methylpropylene glycol, with a mass ratio of n-propyl acetate:isopropyl alcohol:methylpropylene glycol = 25:3:8.

[0085] [Examples 2-22, Comparative Examples 1-4] (Manufacturing of gravure inks S2-S22, T1-T4) Gravure inks S2-S22 and T1-T4 were obtained using the same method as for gravure ink S1, except for changes to the raw materials and mixing ratios listed in Tables 2 and 3. The abbreviations in the tables are as follows. • Cellulose resin solution: Nitrocellulose manufactured by ICI Novel Enterprises, product name DLX5-8, solids content 24% by mass

[0086] [Example 23] (Manufacturing of gravure ink S23) Gravure ink S23 was prepared by stirring and mixing 10 parts by mass of pigment (LIONOL BLUE FG-7358-G, manufactured by Toyo Color Co., Ltd.), 16 parts by mass of polyester polyurethane resin solution, 12 parts by mass of vinyl chloride-vinyl acetate copolymer resin solution (product name Solvine TA5R, manufactured by Nisshin Chemical Industry Co., Ltd., solids content 24% by mass), 3 parts by mass of wax (slightly acidic polyethylene wax, product name 320MP, manufactured by Mitsui Chemicals, Inc.), 1.5 parts by mass of ethyl acetate, 1.5 parts by mass of isopropanol, and 18 parts by mass of mixed solvent. After dispersion using a bead mill (sand mill), 20 parts by mass of polyester polyurethane resin solution and 18 parts by mass of mixed solvent were added and stirred and mixed. The mixed solvent was a mixture of n-propyl acetate, ethyl acetate, isopropyl alcohol, and methylpropylene glycol (mixing ratio: n-propyl acetate:isopropyl alcohol:methylpropylene glycol = 25:3:8). The dispersion time for Preparation Example 7 and the dispersion time for Example 23 were approximately the same. The D50 of the hydrocarbon wax contained in Example 23 was 13 μm and the D80 was 26 μm, which were the same values ​​as in Preparation Example 7.

[0087] (Printing with Gravure Ink S1) Using a gravure proofing machine equipped with a solid gravure printing plate for Helio 175 lines, the gravure ink S1 obtained in Example 1 was coated onto a PET (polyethylene terephthalate) film (manufactured by Toyobo Co., Ltd., product name: E-5102, film thickness: 12 μm) at a coating speed of 150 m / min to obtain a dry film thickness of approximately 2 μm. The film was then dried with hot air at 60°C (airflow 80%) to obtain a printed material.

[0088] (Printing with gravure inks S2-S23, T1-T4) The printed materials were obtained using the same method as for printing with gravure ink S1, except that gravure ink S1 was replaced with gravure inks S2-S23 and T1-T4.

[0089] (Fabrication of laminates using gravure ink S1) In the printed material using the gravure ink S1 obtained above, a methanol solution (1% solid content by mass) of a butadiene-based anchor coating agent (EL451, manufactured by Toyo Morton Co., Ltd.) was further applied to the printing ink layer and dried. Then, molten polyethylene (Sumikasen L417, manufactured by Sumitomo Chemical Co., Ltd.) was extruded at 320°C at a line speed of 100 m / min using an extrusion laminating machine (manufactured by Musashino Kikai Co., Ltd.) to a thickness of 15 μm, and a CPP film (FCMN, manufactured by Futamura Chemical Co., Ltd., with a film thickness of 20 μm) was bonded (laminated) onto the molten polyethylene to obtain a laminate using gravure ink S1.

[0090] (Fabrication of laminates using gravure inks S2-S23 and T1-T4) Each laminate was obtained using the same method as the laminate using gravure ink S1 described above, except that gravure ink S1 was replaced with gravure inks S2-S23 and T1-T4.

[0091] (Measurement and evaluation) The printed materials and laminates using the inks obtained in the above examples and comparative examples were evaluated as follows. The evaluation results are shown in Tables 2 and 3. Similarly, the gravure ink S23 obtained in Example 23, and the printed materials and laminates produced using it were evaluated, and the results were 5 for trapping properties, 5 for long-run suitability, 5 for blocking resistance, and 5 for laminate strength.

[0092] (Trapping properties) The trapping properties of printed materials using the inks obtained in Examples 1-23 and Comparative Examples 1-4 were evaluated in the 70%-100% gradation areas using a Keyence microscope (VHX-5000). The evaluation was performed on the solid color areas. 5 (Excellent): The printed area is even and free of inconsistencies. 4 (Good): There are slight inconsistencies in the printed areas. 3 (Acceptable): The printed area is uneven. 2 (Inferior): There are some noticeable inconsistencies in the printed areas. 1 (Unacceptable): There are large inconsistencies and mottled patterns throughout the printed area. Note that values ​​3-5 are within a range that does not pose any practical problems.

[0093] (Suitable for long-distance running) For gravure inks S1-S23 and T1-T4, a 1-hour printing test was conducted under the same conditions as for gravure ink S1 to evaluate their suitability for long-run printing. Visual inspection was performed to assess the degree of ink coverage during printing, as well as appearance defects such as color unevenness (a phenomenon where the printed material shows variations in shade) and streaks (a phenomenon where the printed material shows streaky unevenness) at the start and end of printing. 5 (Excellent): No overprinting whatsoever, and no color unevenness or streaks in the printed material from the start to the end of printing. 4 (Good): There is some plate overlap, and slight differences in color and streaks between the start and end of printing. 3 (Acceptable): There is plate overlap, and differences in color and streaks between the start and end of printing. 2 (Poor): There is noticeable color unevenness and streaking between the start and end of printing, as well as color bleeding. 1 (Unacceptable): There is significant color unevenness and streaking in the printed material between the start and end of printing, due to plate overlap. Note that values ​​3-5 are within a range that does not pose any practical problems.

[0094] (Blocking resistance) For printed materials using the inks obtained in Examples 1-23 and Comparative Examples 1-4, the non-corona discharge treated surface of a PET (polyethylene terephthalate) film (manufactured by Toyobo Co., Ltd., product name: E-5102, film thickness: 12 μm) and the printed surface of the printed material were subjected to a temperature test of 40°C and a pressure of 5 kg / cm². 2 The materials were pressed together for 24 hours under these conditions, and the resistance to peeling and the degree of peeling of the printed surface were evaluated. [Evaluation Criteria] 5 (Excellent): There is no peeling on the printed surface, and no resistance is felt. 4 (Good): There is no peeling on the printed surface, but some resistance can be felt. 3 (Acceptable): Less than 20% slight peeling on the printed surface. 2 (Not acceptable): There is light peeling of 20% to less than 50% on the printed surface and / or heavy peeling. 1 (Poor): More than 50% peeling on the printed surface. Note that values ​​3-5 are within a range that does not pose any practical problems.

[0095] (Lamination strength) For the laminates using the inks obtained in Examples 1-23 and Comparative Examples 1-4, cut sections 150 mm in length and 15 mm in width were used. The ink / PET film interface was peeled off at one end face to a width that could be held in place by the jig of a tensile testing machine, and the laminate strength in the 90° direction was measured using a tensile testing machine (small tensile testing machine manufactured by Intesco) at a peeling speed of 300 mm / min. 5 (Excellent): Lamination strength of 1.5 N / 15 mm or higher 4 (Good): Lamination strength is 1.0 N / 15 mm or higher, and less than 1.5 N / 15 mm. 3 (Acceptable): Lamination strength of 0.8 N / 15 mm or more, and less than 1.0 N / 15 mm. 2 (Not acceptable): Lamination strength of 0.5N / 15mm or more, and less than 0.8N / 15mm. 1 (Inferior): Laminate strength less than 0.5 N / 15 mm Note that values ​​3-5 are within a range that does not pose any practical problems.

[0096] [Table 2]

[0097] [Table 3]

[0098] Comparative Examples 1 and 2, in which the average particle size (D50) of the hydrocarbon wax obtained by mill dispersion in the presence of an organic solvent was not 4-20 μm, Comparative Example 3, which did not include the dispersion step of mill dispersion of hydrocarbon wax in the presence of an organic solvent, and Comparative Example 4, which did not include hydrocarbon wax, had practical problems in two or more of the following performance aspects: trapping properties, long-run suitability, blocking resistance, and laminate strength. In contrast, Examples 1-23, which included hydrocarbon wax and a dispersion step of mill dispersion of hydrocarbon wax in the presence of an organic solvent to adjust the average particle size to 4-20 μm, achieved practically acceptable performance in all aspects: trapping properties, long-run suitability, blocking resistance, and laminate strength. In other words, the present invention demonstrates that it is possible to provide a printed material manufacturing method that solves all the problems.

Claims

1. A method for producing gravure or flexographic ink, comprising a pigment, a binder resin, a hydrocarbon wax, and an organic solvent, A method for producing gravure or flexographic ink, comprising a dispersion step of mill-dispersing the hydrocarbon wax in the presence of the organic solvent to adjust the average particle size (D50) in the particle size distribution of the hydrocarbon wax to 4 μm to 20 μm.

2. A method for producing gravure or flexographic ink according to claim 1, wherein the penetration degree of the hydrocarbon wax is 1 to 14.

3. A method for producing gravure or flexographic ink according to claim 1 or 2, wherein the hydrocarbon wax is polyethylene wax and / or Fischer-Tropsch wax.

4. A method for producing gravure or flexographic ink according to claim 1 or 2, wherein in the dispersion step, the ratio (D80 / D50) of the hydrocarbon wax to the average particle size (D50) of the particle size distribution at a cumulative frequency of 80% (D80) is 3.0 or less.

5. A method for producing gravure or flexographic ink according to claim 1 or 2, wherein in the dispersion step, the particle size (D80) of the hydrocarbon wax with a cumulative frequency of 80% in the particle size distribution is 60 μm or less.

6. A method for producing gravure or flexographic ink according to claim 1, wherein the binder resin includes a polyurethane resin.

7. A method for producing a gravure or flexographic ink according to claim 6, wherein the polyurethane resin contains structural units derived from a polyester polyol, which is a condensation reaction product of a dibasic acid and a diol.

8. A method for producing gravure or flexographic ink according to claim 1 or 6, wherein the binder resin comprises a vinyl chloride copolymer resin and / or a cellulose-based resin.

9. A method for producing gravure or flexographic ink according to claim 1 or 2, wherein the organic solvent includes an ester-based organic solvent and / or an alcohol-based organic solvent.

10. A method for manufacturing a printed material, comprising: step 1 of manufacturing an ink by the method for manufacturing gravure or flexographic ink described in claim 1; and step 2 of printing the ink onto a substrate 1 after step 1.

11. A method for manufacturing a laminate, comprising: step 1, manufacturing an ink by the gravure or flexographic ink manufacturing method described in claim 1; step 2, manufacturing a printed material on which the ink is printed after step 1; and step 3, laminating the substrate 2 on the printed material after step 2.

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