JP2020055970A - Printing ink for laminate - Google Patents

Abstract

To provide a printing ink for a laminate, which has all of adhesiveness to a film, lamination adaptability and printability with fluidity maintained even at a high concentration.SOLUTION: The printing ink for a laminate comprises a chlorinated polyolefin (A), at least one compound selected from the group consisting of an ethylene vinyl acetate copolymer (B1), a chlorinated ethylene vinyl acetate copolymer (B2) and a copolymer (B3) of vinyl chloride and isobutyl vinyl ether, a rosin (C1) and/or a rosin derivative (C2), and an organic solvent (D). The acid value of the rosin (C1) and the rosin derivative (C2) is 200 mgKOH/g or more.SELECTED DRAWING: None

Description

  The present invention relates to a printing ink for lamination that can be used as a gravure ink or flexo ink for flexible packaging, and more particularly, to a film having excellent adhesion to a film substrate, suitability for lamination, and excellent printability while maintaining fluidity even at a high concentration. The present invention relates to a printing ink for lamination for a substrate.

  In recent years, gravure inks and flexographic inks have been widely used for the purpose of imparting functionalities such as aesthetics and surface protection to a printed material of a soft packaging film. Gravure printing, flexo-printed printing medium, especially when used as a laminating ink based on plastic film among packaging materials, substrate adhesion according to the diversification of film substrate types, even in high concentration It is required to be excellent in printability while maintaining fluidity. In the case of performing dry lamination using a urethane-based adhesive or the like after printing to impart film strength or airtightness, post-processing suitability such as lamination strength is also required.

For example, a printing ink containing chlorinated polypropylene as a main resin has been conventionally used because of its high adhesion to a base material and low raw material cost (for example, Patent Documents 1 to 6). It is said that pigment dispersibility is improved by using an acid-modified chlorinated polyolefin resin as the pigment dispersion resin (for example, Patent Document 2).
Further, studies have been made to improve printability even when toluene having high solubility is not contained (for example, Patent Documents 3 to 5).
Further, Patent Literature 6 is cited as an improvement in plate clogging which affects highlight transferability. However, improvement in density reduction caused by the phenomenon of plate clogging cannot be said to be sufficient. It is desired to develop a laminating printing ink which does not cause a decrease in fluidity even at a high concentration while maintaining the above-mentioned properties.

Japanese Patent No. 2506404 JP 2002-294128 A JP 2006-57056 A Japanese Patent No. 46672335 Japanese Patent No. 46672336 JP-A-2006-188274

  An object of the present invention is to provide a laminating printing ink that has both adhesion to a film, suitability for lamination, and printability that maintains fluidity even at a high concentration.

  The laminating printing ink of the present invention comprises a chlorinated polyolefin (A), an ethylene-vinyl acetate copolymer (B1), a chlorinated ethylene-vinyl acetate copolymer (B2), and a copolymer of vinyl chloride and isobutyl vinyl ether ( B3) a printing ink for lamination containing at least one selected from the group consisting of rosin (C1) and / or rosin derivative (C2), and organic solvent (D), wherein rosin (C1 ) And the rosin derivative (C2) were found to be effective in solving the problem by specifying the acid value.

  That is, in the present invention, the printing ink for lamination of the present invention is a chlorinated polyolefin (A), an ethylene-vinyl acetate copolymer (B1), a chlorinated ethylene-vinyl acetate copolymer (B2), and vinyl chloride and isobutyl vinyl ether. And a rosin (C1) and / or a rosin derivative (C2), and an organic solvent (D). And a rosin derivative (C1) and a rosin derivative (C2) having an acid value of 200 mgKOH / g or more.

  Furthermore, the present invention relates to a laminating printing ink in which the total amount of the rosin (C1) and / or the rosin derivative (C2) is 0.1 to 5% by mass of the total amount of the ink.

  Further, the present invention relates to a printing ink for lamination, wherein the organic solvent (D) does not contain an aromatic hydrocarbon solvent.

  Furthermore, the present invention relates to a printed material obtained by printing the printing ink for lamination on a plastic film using a gravure printing machine.

  According to the present invention, it is possible to provide a printing ink for laminating, which has both adhesion to a film, suitability for lamination, and printability while maintaining fluidity even at a high concentration, and a printed material obtained by printing the printing ink.

  The present invention will be described in detail. In the following description, "ink" means "printing ink for lamination". All “parts” indicate “parts by mass”, and all “%” indicate “% by mass”.

  The laminating printing ink of the present invention comprises a chlorinated polyolefin (A), an ethylene-vinyl acetate copolymer (B1), a chlorinated ethylene-vinyl acetate copolymer (B2), and a copolymer of vinyl chloride and isobutyl vinyl ether ( B3) a printing ink for lamination containing at least one selected from the group consisting of rosin (C1) and / or rosin derivative (C2), and organic solvent (D), wherein rosin (C1 ) And the rosin derivative (C2) have an acid value of 200 mgKOH / g or more.

  The chlorinated polyolefin (A) used in the printing ink for lamination of the present invention will be described. The chlorinated polyolefin (A) can be obtained by introducing a chlorine atom into the polyolefin, and the polyolefin is not particularly limited and may be, for example, an α-olefin such as ethylene, propylene, 1-butene, and 4-methyl-1-pentene. A resin composed of a copolymer of a system unsaturated hydrocarbon or a homopolymer can be used. As the copolymer, propylene-α-butene copolymer, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-vinyl acetate copolymer, ethylene-1-butene copolymer, polyethylene , Poly-4-methyl-1pentene and the like can be mentioned as examples.

The method for producing the chlorinated polyolefin (A) includes a solution chlorination method in which a polyolefin is dissolved in an organic solvent such as carbon tetrachloride and chlorination, a method in which the polyolefin is chlorinated in an aqueous suspension state, and a method in which the polyolefin is in a bulk state. Any method may be used.
The chlorinated polyolefin (A) may be an acid-modified chlorinated polyolefin resin in which α, β-unsaturated carboxylic acid and / or a derivative thereof and chlorine are introduced into the polyolefin.
Further, as a method for producing the acid-modified chlorinated polyolefin, for example, a polyolefin is acid-modified with an α, β-unsaturated carboxylic acid and / or a derivative thereof to obtain an acid-modified polyolefin, and then a chlorinated solvent such as chloroform. May be blown with chlorine gas to introduce chlorine into the acid-modified polyolefin.

  Examples of the α, β-unsaturated carboxylic acid and / or its derivative include fumaric acid, maleic acid, maleic anhydride, citraconic acid, citraconic anhydride, mesaconic acid, itaconic acid, itaconic anhydride, aconitic acid, and anhydride. Examples thereof include aconitic acid, hymic acid anhydride, (meth) acrylic acid, and (meth) acrylate.

As the chlorinated polyolefin (A) used in the laminating printing ink of the present invention, a chlorinated polyolefin having a chlorine content of 5 to 50% by mass is preferably used.
Representative examples of the chlorinated polyolefin (A) include a chlorinated polypropylene resin. The chlorinated polypropylene resin preferably has a chlorination degree of 30 to 45% and a weight average molecular weight of 5,000 to 50,000.
The chlorination degree is the mass% of chlorine atoms in the chlorinated polypropylene resin. If the chlorination degree is less than 30%, the solubility in the organic solvent tends to decrease, and if it exceeds 45%, the adhesion to the film substrate tends to decrease. When the weight average molecular weight is less than 5,000, the effect of adhesion to the film substrate is hardly obtained, and when it exceeds 50,000, the solubility, particularly the solubility in an ester solvent or an alcohol solvent, tends to decrease.

In the laminating printing ink of the present invention, any one selected from the group consisting of ethylene vinyl acetate copolymer (B1), chlorinated ethylene vinyl acetate copolymer (B2), and copolymer of vinyl chloride and isobutyl vinyl ether (B3) One or more can be used.
The ethylene-vinyl acetate copolymer (B1) is a resin containing a structural unit derived from ethylene and a structural unit derived from vinyl acetate in specific amounts.
As the ethylene-vinyl acetate copolymer (B1), those having a vinyl acetate content of 20% by mass or more and 50% by mass or less of the whole copolymer are preferable. When the content of vinyl acetate is 20% by mass or more, the adhesiveness and transferability of the ink film tend to be maintained, and when the content of vinyl acetate is 50% by mass or less, the lamination strength of the ink decreases. Can be retained.
Furthermore, it is more preferable that the content of vinyl acetate is 30% by mass or more and 40% by mass or less of the whole copolymer.
In addition, the content of the structural unit derived from vinyl acetate is based on the measuring method specified in JIS K7192: 1999.

  The chlorinated ethylene-vinyl acetate copolymer (B2) used in the present invention is obtained by further introducing a chlorine atom into the ethylene-vinyl acetate copolymer (B1) to obtain a chlorinated ethylene-vinyl acetate copolymer (B2). Can be done.

The printing ink for lamination of the present invention contains any one of an ethylene vinyl acetate copolymer (B1), a chlorinated ethylene vinyl acetate copolymer (B2), and a copolymer of vinyl chloride and isobutyl vinyl ether (B3). And two or three of these may be used in combination.
In particular, when a hydrocarbon solvent such as methylcyclohexane is used in the printing ink for lamination of the present invention, the use of the ethylene vinyl acetate copolymer (B1) and the chlorinated ethylene vinyl acetate copolymer (B2) together causes It is more preferable from the viewpoints of clogging, laminating strength and adhesiveness. The ratio between the ethylene vinyl acetate copolymer and the chlorinated ethylene vinyl acetate copolymer is more preferably from 10/90 to 40/60 in terms of solids weight ratio.

It is essential that the printing ink for lamination of the present invention contains a rosin (C1) and / or a rosin derivative (C2) for the purpose of improving the ink transfer property observed in plate clogging.
Examples of the rosin (C1) include rosin, hydrogenated rosin, acid-modified rosin, and ester rosin.
Examples of the rosin include unmodified rosins such as tall oil rosin, gum rosin, and wood rosin having a resin acid such as abietic acid, levopimaric acid, palustric acid, neoabietic acid, dehydroabietic acid, or dihydroabietic acid as a main component.
The hydrogenated rosin can be used as hydrogenated rosin.
Examples of the acid-modified rosin include fumaropimaric acid obtained by adding fumaric acid to rosin by a Diels-Alder addition reaction and maleopimaric acid obtained by adding maleic acid.
Among the acid-modified rosins, rosin maleate is particularly preferred.
Examples of the esterified rosin include a glycerin ester obtained by esterifying rosin and glycerin, and a pentaerythritol ester obtained by esterifying with pentaerythritol.

  As the rosin derivative (C2), an unsaturated carboxylic acid-modified rosin obtained by reacting the above rosins with an unsaturated carboxylic acid such as maleic acid, fumaric acid or acrylic acid can be used. As the polyhydric alcohol, any one having a dihydric or higher alcoholic hydroxyl group can be used, and specifically, glycerin, trimethylolethane, trimethylolpropane, diethylene glycol, triethylene glycol, Examples thereof include 6-hexanediol and pentaerythritol.

The rosin (C1) and the rosin derivative (C2) used in the laminating printing ink of the present invention must have an acid value of 200 mgKOH / g or more.
Generally, a pigment used as a coloring material of a laminating printing ink has a high surface polarity, so that the binder used in the laminating printing ink of the present invention is hardly adsorbed on the pigment surface. When the pigment component is increased to increase the concentration, the fluidity tends to deteriorate. As a result, the amount of the solvent used for diluting the ink to the viscosity at the time of printing increases, and high-density printing tends to be difficult.
The acid groups of the high acid value rosin and its derivatives have excellent wettability to the pigment surface, and can produce an ink having good fluidity even at a high pigment concentration. In particular, recently, there has been a demand to reduce the amount of ink used and the amount of discharged organic solvent by increasing the concentration of the ink, and high-density ink is effective for reproducing beautiful pictures.
Therefore, if the rosin and / or rosin derivative has an acid value of 200 mgKOH / g or more and an upper limit of 400 mgKOH or less, a low-viscosity ink can be obtained due to high pigment dispersibility, and high-density printing can be performed.

The rosin (C1) and the rosin derivative (C2) used in the printing ink for lamination of the present invention will be described. The total amount of the rosin (C1) and / or the rosin derivative (C2) is preferably in the range of 0.1 to 5% by mass of the total amount of the ink. By adding 0.1% by mass or more of the total amount of rosin (C1) and / or rosin derivative (C2), the adhesiveness and transferability of the ink film tend to be maintained, and by adding the total amount to 5% by mass or less. The lamination strength of the ink can be maintained.
The softening points of the rosin (C1) and the rosin derivative (C2) are preferably from 100 to 170C. When the softening point is 100 ° C. or higher, the tendency of the ink coating film to be softened and the blocking property to be reduced can be suppressed. When the softening point is 170 ° C. or lower, the tendency for the solubility in a solvent to be reduced can be avoided. Storage stability tends to be maintained.

  The organic solvent used in the printing ink for lamination of the present invention is not particularly limited, and for example, aromatic hydrocarbons such as toluene, xylene, Solvesso # 100, Solvesso # 150, hexane, methylcyclohexane, heptane, octane, Examples thereof include various organic solvents such as aliphatic hydrocarbons such as decane, and esters such as methyl acetate, ethyl acetate, isopropyl acetate, normal propyl acetate, butyl acetate, amyl acetate, ethyl formate, and butyl propionate. Examples of water-miscible organic solvents include alcohols such as methanol, ethanol, propanol, butanol and isopropyl alcohol, ketones such as acetone, methyl ethyl ketone and cyclohexanone, ethylene glycol (mono, di) methyl ether, and ethylene glycol (mono, di) ethyl. Ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono, di) methyl ether, diethylene glycol (mono, di) ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono, Di) methyl ether, propylene glycol (mono, di) methyl ether, propylene glycol Over mono propyl ether, propylene glycol monobutyl ether, dipropylene glycol (mono, di) include various organic solvents glycol ether such as methyl ether. These can be used alone or in combination of two or more.

Among them, from the viewpoint of solubility in the chlorinated polyolefin (A), ethylene-vinyl acetate copolymer (B1), and chlorinated ethylene-vinyl acetate copolymer (B2), a mixed solution of methylcyclohexane / cyclohexane / methylethylketone / ethylacetate; Or, toluene / cyclohexane / methyl ethyl ketone is more preferable. If the amount is less than 10% by mass of the total amount of the ink, glycol ethers can be added for drying adjustment.
It is more preferable not to use an aromatic hydrocarbon solvent such as toluene and xylene from the viewpoint of both work hygiene during printing and harmfulness of the packaging material.
Furthermore, use of hydrocarbon solvents such as methylcyclohexane and ethylcyclohexane may be avoided from the viewpoint of odor. In this case, from the viewpoints of solubility and ink stability, the chlorinated ethylene-vinyl acetate copolymer (B2) is more preferable than the ethylene-vinyl acetate copolymer (B1) or the copolymer of vinyl chloride and isobutyl vinyl ether (B3). Preferably, it is used.
The chlorination degree is preferably in the range of 5 to 40. Within this range, the dispersibility of the pigment and the solubility in a non-methylcyclohexane solvent will be good. Here, the chlorination degree of the chlorinated ethylene-vinyl acetate copolymer (B2) in the present invention is the mass% of chlorine atoms in the ethylene-vinyl acetate copolymer.

  The pigment used in the printing ink for lamination of the present invention may be either a color pigment or a white pigment. If a white pigment is added, for example, back printing gravure printing can be used as a white ink corresponding to the background of a picture.

  Examples of the coloring pigment used in the printing ink for lamination of the present invention include organic pigments and dyes used in general inks, paints, recording agents, and the like. As organic pigments, azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethineazo, dictopyrrolopyrrole, isoindoline and the like Pigments.

As the color index name,
C. I. Pigment Yellow 1, 3, 12, 13, 14, 17, 42, 74, 83;
C. I. Pigment Orange 16;
C. I. Pigment Red 5, 22, 38, 48: 1, 48: 2, 48: 4, 49: 1, 53: 1, 57: 1, 63: 1, 81, 101;
C. I. Pigment Violet 19, 23;
C. I. Pigment Blue 23, 15: 1, 15: 3, 15: 4, 17: 1, 18, 27, 29
C. I. Pigment Green 7, 36, 58, 59;
C. I. Pigment Black 7;
C. I. Pigment White 4, 6, 18 and the like.

  For indigo ink, C.I. I. Pigment Blue 15: 3 (copper phthalocyanine) and yellow ink are C.I. I. Pigment Yellow 83, Crimson Ink for C.I. I. Pigment Red 57: 1 is preferably used. It is preferable to use carbon black for the black ink, aluminum for the gold and silver inks, and mica (mica) for the pearl ink from the viewpoint of cost and coloring power. Aluminum is in powder or paste form, but is preferably used in paste form from the viewpoint of handleability and safety. Whether to use leafing or non-leafing is appropriately selected from the viewpoint of brightness and density.

Examples of the white pigment used in the laminating printing ink of the present invention include, for example, titanium oxide, zinc sulfide, lead white, zinc white, lithopone, antimony white, basic lead sulfate, basic lead silicate, and barium sulfate. , Calcium carbonate, gypsum, silica, and the like.
The average particle size of the pigment is preferably in the range of 10 to 400 nm, more preferably about 50 to 350 nm.
The amount of the coloring pigment is preferably in the range of 1 to 20% by mass of the total amount of the ink in order to obtain sufficient image density and light resistance of a printed image.

  In the present invention, if necessary, a combination resin, an extender, a pigment dispersant, a leveling agent, an antifoaming agent, a wax, a plasticizer, an infrared absorber, an ultraviolet absorber, an aromatic agent, a flame retardant, and the like can also be included. .

  Examples of the resin used as needed in the laminating printing ink of the present invention include resins other than the chlorinated polyolefin, ethylene vinyl acetate copolymer, chlorinated ethylene vinyl acetate copolymer rosin, for example, polyurethane resin , Vinyl acetate resin, acrylic resin, polyester resin, alkyd resin, polyvinyl chloride resin, ketone resin, cyclized rubber, chloride rubber, butyral, petroleum resin and the like. The combined resins can be used alone or in combination of two or more. The content of the combined resin is preferably from 1 to 25% by mass, more preferably from 2 to 15% by mass, based on the total mass of the ink.

  In order to stably disperse the pigment in the organic solvent, the resin can be dispersed alone, but a dispersant may be used in combination to further stably disperse the pigment. As the dispersant, an anionic, nonionic, cationic, amphoteric or other surfactant can be used. For example, a comb-shaped polymer compound obtained by adding a polyester to polyethyleneimine, or an alkylamine derivative of an α-olefin maleic acid polymer can be used. Specific examples include the Solspers series (LUBRIZOL), the Addisper series (Ajinomoto), and the homogenol series (Kao). Also, BYK series (Big Chemie), EFKA series (EFKA) and the like can be used as appropriate. The dispersant is preferably contained in the ink in an amount of 0.05% by mass or more based on the total mass of the ink from the viewpoint of storage stability of the ink, and 5% by mass or less from the viewpoint of suitability for lamination. 0.1 to 2% by mass.

  The printing ink for lamination of the present invention can be produced by dissolving and / or dispersing each resin, colorant and the like in an organic solvent. Specifically, it is possible to manufacture a pigment dispersion in which a pigment is dispersed in an organic solvent with each resin, and to manufacture an ink by blending the obtained pigment dispersion with other compounds as necessary. it can.

The particle size distribution of the pigment in the pigment dispersion is adjusted by appropriately adjusting the size of the pulverization medium of the disperser, the filling rate of the pulverization medium, the dispersion treatment time, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, and the like. be able to. As the disperser, a commonly used roller mill, ball mill, pebble mill, attritor, sand mill, or the like can be used.
When bubbles or unexpectedly large particles are included in the ink, it is preferable to remove the ink by filtration or the like in order to reduce the quality of the printed matter. A conventionally known filter can be used.

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

As a plastic film that can be used as a base material, polypropylene (PP) is mainly used, but there is no particular limitation. For example, polyamide resins such as nylon 6, nylon 66, and nylon 46, polyethylene phthalate (PET), Polyester resins such as polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polyhydroxycarboxylic acids such as polylactic acid, poly (ethylene succinate), poly (butylene succinate) ), A film made of a thermoplastic resin such as a biodegradable resin represented by an aliphatic polyester resin, a polyolefin resin such as polyethylene, a polyimide resin, a polyarylate resin, or a mixture thereof, or a product of these films. Body including but among them, polyesters, polyamides, polyethylene, films of polypropylene can be preferably used.
These films may be unstretched films or stretched films, and their production methods are not limited. Also, the thickness of the base film is not particularly limited, but usually may be in the range of 1 to 500 μm.
Further, it is preferable that the printed surface of the film is subjected to a corona discharge treatment because the adhesion of the substrate can be further improved. Further, silica, alumina, or the like may be deposited.
In addition, as a printing method, printing can be performed by a printing method using a known plate such as gravure printing or flexographic printing, but printing by a gravure printing method is particularly preferable. As the cylinder used for gravure printing, a known cylinder such as an engraving type or a corrosion type is used.
In addition, the printing ink for lamination of the present invention may have a viscosity of 5 to 19 seconds at 25 ° C. in a Zaancup # 4 manufactured by Rigo Co., and more preferably 8 to 8 at the time of the base ink of the meat mixture. 18 seconds. If the viscosity is expressed in millipascal seconds, it may be in the range of 50 to 240 (mPa · s) at 25 ° C., and more preferably in the range of 80 to 220 (mPa · s).
The viscosity when the base ink of the continuous meat mixture is diluted and adjusted into a printing ink using a mixed solvent as appropriate is in the range of 13 to 18 seconds at 25 ° C. with Zaan Cup # 3 manufactured by Rigo Co., and 60 to 100 (mPa). -The range of s) is preferred.

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

(Preparation of resin solution of ethylene-vinyl acetate copolymer (B1))
As a resin solution of the ethylene-vinyl acetate copolymer (B1), Evaflex EV40W manufactured by DuPont-Mitsui Polychemicals; ethyl acetate / methyl ethyl ketone / methyl cyclohexane = 20/20 / A resin solution (B1L) was added at a mass ratio of 40 and dissolved to a solid content of 20%.

(Preparation of Resin Solution of Chlorinated Ethylene Vinyl Acetate Copolymer (B2))
As a resin solution of the chlorinated ethylene-vinyl acetate copolymer (B2), ethyl acetate / normal propyl acetate / methyl ethyl ketone = 20/20/40 was applied to CEVA B-3 (chlorination degree: 30 to 40) manufactured by Zhuzhou North Plastic Co., Ltd. And a resin solution (B2L) dissolved to a solid content of 20% was prepared.

(Preparation of copolymer (B3) solution of vinyl chloride and isobutyl vinyl ether)
20 parts of Raloflex MP-45 (manufactured by BASF), which is a copolymer of vinyl chloride and isobutyl vinyl ether, and 80 parts of a mixed solvent of ethyl acetate / normal propyl acetate / methylcyclohexane = 20/20/40 are added and sufficiently stirred. Then, a resin solution (B3L) of a copolymer of vinyl chloride and isobutyl vinyl ether having a solid content of 20% was prepared.

(Adjustment of mixed solvent I)
As a mixed solvent I used for the base ink and the ink preparation after the mixing, a mixed solvent I was prepared by mixing normal propyl acetate / methyl ethyl ketone / methyl cyclohexane = 25/25/50 in a mass ratio.

[Preparation Example 1: Preparation of indigo pigment dispersion]
10 parts of an indigo pigment Fastogen BlueFA5380 (manufactured by DIC), 15 parts of a resin solution (B1L) of an ethylene-vinyl acetate copolymer (B1), 10 parts of a resin solution (B2L) of a chlorinated ethylene-vinyl acetate copolymer (B2), 15 parts of the mixed solution I was added, and the mixture was kneaded with a mighty mill (manufactured by Inoue Seisakusho) to prepare an indigo pigment dispersion.

[Adjustment Example 2: Preparation of rosin solution (R1)]
50 parts of pine crystal KE-604 (acid value 230 mgKOH / g, manufactured by Arakawa Chemical Industry Co., Ltd.), which is a rosin derivative (C2), and 50 parts of isopropyl alcohol were sufficiently stirred to prepare a rosin solution (R1).

[Adjustment Example 3: Preparation of rosin solution (R2)]
As rosin (C1), 50 parts of Marquid # 33 (acid value 310 mg KOH / g, manufactured by Arakawa Chemical Industry Co., Ltd.), which is rosin maleate, and 50 parts of isopropyl alcohol were added and sufficiently stirred to prepare a rosin solution (R2).

[Preparation Example 4: Preparation of rosin solution (R3)]
As rosin (C1), 50 parts of Marquid N0.5 (acid value: 25 mg KOH / g or less, manufactured by Arakawa Chemical Industries, Ltd.), which is a rosin maleate, and 50 parts of ethyl alcohol were added and sufficiently stirred to prepare a rosin solution (R3). .

[Adjustment Example 5: Preparation of rosin solution (R4)]
50 parts of pine crystal KR-614 (acid value: 175 mg KOH / g, manufactured by Arakawa Chemical Industry Co., Ltd.), which is a rosin derivative (C2), and 50 parts of isopropyl alcohol were added and sufficiently stirred to prepare a rosin solution (R4).

[Example 1]
Indigo pigment dispersion 12 parts, rosin solution (R1) 1 part, ethylene vinyl acetate copolymer resin solution (B1L) 15 parts, vinyl chloride and isobutyl vinyl ether copolymer solution (B3L) 15 parts, mixed solvent I A total of 58 parts of 15 parts were added and stirred to prepare an indigo base ink.
Subsequently, the above-mentioned indigo base ink was used as a chlorinated polyolefin (A) as Supercron 360T (chlorination degree 31, solid content 60% (using ethyl acetate solvent), CAS No. 68442-33-1, chlorinated polypropylene, Japan) 5 parts, a copolymer solution (B3L) of vinyl chloride and isobutyl vinyl ether (8 parts) and 29 parts of mixed solvent I were added, and a total of 100 parts were sufficiently stirred to prepare an indigo ink.

[Examples 2 to 8]
In Examples 2 to 8, indigo inks were prepared in the same procedure as in Example 1 based on the formulations shown in Tables 1 and 2. In Examples 6 and 8, chlorinated polyolefin (A), Supercron E (chlorination degree: 29.5, solid content: 20% (using toluene), CAS No. 68442-33-1, chlorinated polypropylene) , Nippon Paper Industries Co., Ltd.) and a predetermined amount of toluene in addition to the mixed solvent I.

[Comparative Examples 1 to 4]
In Comparative Examples 1 to 4, indigo inks were produced in the same procedure as in Example 1 based on the formulations shown in Table 2.

  Using the prepared indigo inks of Examples 1 to 8 and Comparative Examples 1 to 4, evaluation tests were performed according to the following procedures.

[Evaluation item 1: Confirmation of ink viscosity]
The viscosity (unit: seconds) of the indigo ink at 25 ° C. based on the blending amounts shown in Tables 1 and 2 was confirmed with Zahn Cup # 4 (manufactured by Rigo Co., Ltd.).

[Evaluation item 2: Calculation of solvent dilution ratio]
The solvent dilution ratio was calculated when the final adjustment was made with ethyl acetate using Zahn Cup # 4 (manufactured by Rigosha Co., Ltd.) so that the final time was 15 seconds (25 ° C.).
When the dilution ratio is high, the amount of the solvent contained in the ink at the time of printing is increased, so that the color density of the printed matter is low. When the dilution ratio is low, the color density is high. The solvent dilution rate is preferably 50% or less.

[Evaluation item 3: Adhesion to film]
The viscosities of the indigo inks shown in Tables 1 and 2 were measured using methyl cyclohexane / methyl ethyl ketone / ethanol = 40/40/20 (for Examples 6 and 8, toluene / methyl ethyl ketone / ethanol = 40/40/20) and Zahn cup # 3. The temperature was adjusted to 16 seconds (25 ° C.) with a gravure proofing machine equipped with a 22 μm deep gravure plate, and a biaxially stretched polypropylene film V (hereinafter, OPP film, P2161 manufactured by Toyobo Co., Ltd., thickness 20 μm) ) Is printed on the corona-treated surface side, and the produced printed matter is left for one day. Then, a cellophane tape (Nichiban 12 mm width) is attached to the printed surface, and the appearance of the printed film when this is rapidly peeled off is as follows. Was visually determined in five stages.

5: The printed film was not peeled at all.
4: 70% or more to less than 90% of the printed film remained on the film.
3: 50% or more to less than 70% of the printed film remained on the film.
2: 30% or more to less than 50% of the printed film remained on the film.
1: Less than 30% of the print film remained.

[Evaluation item 4: Lamination suitability]
Printed material produced with a biaxially stretched polypropylene film V (OPP film, manufactured by Toyobo Co., Ltd., P2161 20 μm thick) was thermally laminated with a polypropylene resin sheet, and the laminate strength was measured using an autograph manufactured by Shimadzu Corporation. .
The sample width was 15 mm, the peeling speed during measurement was 300 mm / min, and the lamination strength was measured.
The practical range is lamination strength of 1.0 N / 15 mm or more.

[Evaluation item 5: Concentration]
A blank sheet was placed below a printed material made of the biaxially stretched polypropylene film V (OPP film, P2161 manufactured by Toyobo Co., Ltd., thickness: 20 μm) of evaluation item 2, and an X-rite spectral densitometer (manufactured by X-Rite Co., Ltd.) from the non-printed surface )), The color density C value was measured. A color density C value of 2.00 or more is a practical range.

5: Color density C value is 2.17 or more 4: Color density C value is 2.15 or more 3: Color density C value is 2.00 or more
2: Color density C value is 1.90 or more 1: Color density C value is less than 1.9

  Tables 1 and 2 show the composition of each indigo ink and the evaluation results.

  From the above results, the laminated printing ink of the present invention is a printing ink whose viscosity is finally adjusted in 15 seconds with Zahn Cup # 4 (manufactured by Rigo Co., Ltd.) while maintaining the adhesion to the film substrate and the suitability for lamination. At the same time, a sufficient concentration was obtained.

  The laminated printing ink of the present invention can be widely used as various gravure printed materials for industrial products such as food packaging materials, sanitary products, cosmetics, and electronic components.

Claims (4)

Any one selected from the group consisting of chlorinated polyolefin (A), ethylene-vinyl acetate copolymer (B1), chlorinated ethylene-vinyl acetate copolymer (B2), and copolymer of vinyl chloride and isobutyl vinyl ether (B3) A laminating printing ink comprising at least one of rosin (C1) and / or a rosin derivative (C2), and an organic solvent (D),
The printing ink for lamination, wherein the rosin (C1) and the rosin derivative (C2) have an acid value of 200 mgKOH / g or more.
The printing ink for lamination according to claim 1, wherein the total amount of the rosin (C1) and / or the rosin derivative (C2) is 0.1 to 5% by mass of the total amount of the ink.
The printing ink for lamination according to claim 1 or 2, wherein the organic solvent (D) does not contain an aromatic hydrocarbon solvent.
  Printed matter obtained by printing the printing ink for lamination according to any one of claims 1 to 3 on a plastic film using a gravure printing machine.