Laminate printing ink composition for soft packaging, and printed matter

Abstract

To provide a laminate printing ink composition for soft packaging which allows for obtaining a printed matter that is excellent in storage stability, as well as, excellent in extrusion laminate strength with respect to an OPP film, a PET film and an NY film, and also excellent in adhesion with respect to the OPP film.SOLUTION: There is provided a laminate printing ink composition for soft packaging containing a pigment, a polyurethane resin, and polymerized rosin ester. Therein: the polymerized rosin ester contains polymerized rosin ester A having an acid value of 50 mgKOH / g or less and a softening point of 95°C to 165°C; and a content of the polymerized rosin ester A is 0.2 mass% to 5.5 mass% with respect to the total solid content mass of the laminate printing ink composition for soft packaging.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a printing ink composition for laminated flexible packaging and a printed matter. [Background technology]

[0002] Packaging materials using various plastic films are used for food, confectionery, household goods, pet food, etc., from the viewpoints of design, economy, content protection, transportability, etc. Furthermore, gravure printing or flexographic printing is applied to many packaging materials with the intention of adding designs, messages, etc. that will appeal to consumers.

[0003] To obtain the packaging material, front printing is performed in which printing is done on the front surface of the base film of the packaging material, or back printing is performed in which an adhesive or anchor agent is applied as necessary to the printed surface on the back surface of the base film of the packaging material and the film is then laminated.

[0004] In reverse printing, colored inks and white ink are printed in sequence on various films such as various general-purpose films (polyester, nylon), aluminum foil, and various high-performance films (films coated with inorganic or organic barrier agents), and then a polyethylene film, polypropylene film, or the like is laminated on the white ink printing layer for the purpose of heat sealing by dry lamination using an adhesive or extrusion lamination using an anchor coating agent.

[0005] For example, Patent Document 1 discloses a white ink composition containing a pigment dispersion (A) containing a titanium oxide pigment (a) and rosins (b), and a polyurethane resin (B), wherein the rosins have an acid value of 150 to 175 mgKOH / g and a weight average molecular weight of 120 to 500. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2013-194121 A Summary of the Invention [Problem to be solved by the invention]

[0007] An ink composition is required to have a performance (storage stability) that is resistant to changes in properties such as clouding, thickening, and gelation over time. In the invention described in Patent Document 1, storage stability is not sufficiently discussed, and there is room for improvement.

[0008] Furthermore, from the standpoint of environmental impact and safety, packaging materials that do not use chlorine-based resins are being considered. When chlorine-based resins are not used, the use of OPP (oriented polypropylene) film, PET (polyethylene terephthalate) film, and NY (nylon) film may be considered. However, the invention described in Patent Document 1 does not fully discuss the extrusion lamination strength for OPP films, PET films, and NY films, and there is room for improvement. Furthermore, there was not enough discussion about the adhesiveness to OPP film, leaving room for improvement.

[0009] Therefore, an object of the present invention is to provide a laminate printing ink composition for flexible packaging which can give printed matter having excellent storage stability, excellent extrusion lamination strength to OPP film, PET film, and NY film, and excellent adhesion to OPP film. [Means for solving the problem]

[0010] The present inventors have discovered that in a laminate printing ink composition for flexible packaging containing a pigment, a polyurethane resin, and a polymerized rosin ester, all of the above-mentioned problems can be solved by including polymerized rosin ester A having an acid value and softening point within specific ranges, and further by setting the content of the polymerized rosin ester A within a specific range relative to the total solids mass, and have thus completed the present invention.

[0011] That is, the present invention is a laminate printing ink composition for flexible packaging comprising a pigment, a polyurethane resin, and a polymerized rosin ester, wherein the polymerized rosin ester comprises polymerized rosin ester A having an acid value of 50 mgKOH / g or less and a softening point of 95°C to 165°C, and the content of the polymerized rosin ester A is 0.2% by mass to 5.5% by mass relative to the total solids mass of the flexible packaging laminate printing ink composition.

[0012] In the flexible packaging laminate printing ink composition of the present invention, the polymerized rosin ester A preferably has an acid value of 20 mgKOH / g or less. The content of the polymerized rosin ester A is preferably 0.7% by mass to 5.0% by mass based on the total solid content mass of the flexible packaging laminate printing ink composition. The present invention also relates to a printed matter obtained by printing the flexible packaging laminate printing ink composition on a flexible packaging substrate. Effect of the Invention

[0013] The present invention can provide a laminate printing ink composition for flexible packaging which can give printed matter having excellent storage stability, excellent extrusion lamination strength to OPP film, PET film, and NY film, and excellent adhesion to OPP film. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] <Laminate printing ink composition for flexible packaging> The flexible packaging laminate printing ink composition of the present invention is a flexible packaging laminate printing ink composition comprising a pigment, a polyurethane resin, and a polymerized rosin ester, wherein the polymerized rosin ester comprises polymerized rosin ester A having an acid value of 50 mgKOH / g or less and a softening point of 95°C to 165°C, and the content of the polymerized rosin ester A is 0.2% by mass to 5.5% by mass relative to the total solids mass of the flexible packaging laminate printing ink composition. The flexible packaging laminate printing ink composition of the present invention can give printed matter that has excellent extrusion lamination strength to OPP film, PET film, and NY film (hereinafter also simply described as "excellent lamination strength to film") and also has excellent adhesion to OPP film (hereinafter also simply described as "excellent adhesion"). Each component will be described in detail below.

[0015] (Pigments) The flexible packaging laminate printing ink composition of the present invention contains a pigment.

[0016] The pigment is not particularly limited, and may be appropriately selected from pigments that have been conventionally used in the field of laminate printing ink compositions for flexible packaging. Examples of the pigments include inorganic color pigments, organic color pigments, and extender pigments. Examples of the inorganic color pigments include titanium oxide, red iron oxide, antimony red, cadmium red, cadmium yellow, cobalt blue, Prussian blue, ultramarine blue, carbon black, and graphite. Examples of the organic color pigments include soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments. Examples of the extender pigments include calcium carbonate, kaolin clay, barium sulfate, aluminum hydroxide, and talc.

[0017] The content of the pigment is preferably 30 to 85% by mass based on the total solid content by mass of the flexible packaging laminate printing ink composition. By containing it in the above range, it is possible to ensure sufficient storage stability while providing excellent color development. The content of the pigment is more preferably 45 to 80% by mass based on the total solid content by mass of the flexible packaging laminate printing ink composition. In this specification, the solid content means the components excluding volatile components such as water and solvents.

[0018] (Polyurethane resin) The flexible packaging laminate printing ink composition of the present invention contains a polyurethane resin.

[0019] As the polyurethane resin, a polyurethane resin having a urea bond with an amino group at the terminal thereof, which has been conventionally used in the field of laminate printing ink compositions for flexible packaging, can be used.

[0020] The polyurethane resin preferably has a urethane group concentration of 0.30 mmol / g or more, more preferably 0.35 mmol / g or more, and even more preferably 0.50 mmol / g or more. In addition, it is preferably 2.40 mmol / g or less, more preferably 2.00 mmol / g or less, and even more preferably 1.70 mmol / g or less. Urethane group concentrations of less than 0.30 mmol / g are relatively uncommon, and those exceeding 2.40 mmol / g tend to result in reduced adhesion to films.

[0021] From the viewpoint of storage stability, the polyurethane resin is preferably a polyurethane resin having an amino group at the terminal (having an amine value). Among such polyurethane resins having amino groups, polyurethane resins having one or more types selected from a primary amino group, a secondary amino group, and a tertiary amino group at the molecular terminal, particularly one or more types selected from a primary amino group and a secondary amino group at the molecular terminal, are more preferred. Further, it is more preferable that the polyurethane resin has a hydroxyl group and at least one type of amino group selected from a primary amino group, a secondary amino group and a tertiary amino group at the molecular terminal. The polyurethane resin can be provided with favorable storage stability by having a specific functional group such as the amino group.

[0022] The amine value of the polyurethane resin is preferably 1.00 to 15.00 mgKOH / g, more preferably 1.50 mgKOH / g or more, even more preferably 2.00 mgKOH / g or more, most preferably 2.50 mgKOH / g or more, and is preferably 14.00 mgKOH / g or less, more preferably 13.00 mgKOH / g or less. By setting the amine value within the above range, it is possible to obtain a printed matter having excellent extrusion lamination strength and printability.

[0023] In this specification, the amine value means the amine value per 1 g of solid content, and refers to a value converted into the equivalent amount of potassium hydroxide after measuring by potentiometric titration (e.g., COMTITE (AUTO TITRATOR COM-900, BURET B-900, TITSTATION K-900), Hiranuma Sangyo Co., Ltd.) using a 0.1 N aqueous hydrochloric acid solution.

[0024] The polyurethane resin is preferably, for example, a polyurethane polyurea resin.

[0025] The polyurethane polyurea resin has at least one type of amino group selected from a primary amino group and a secondary amino group at the molecular terminal. The polyurethane polyurea resin is preferably a polyurethane polyurea resin having a hydroxyl group and at least one type selected from a primary amino group and a secondary amino group at the molecular terminal. As the polyurethane polyurea resin, a polyurethane polyurea obtained by synthesizing a urethane prepolymer by reacting an organic diisocyanate compound described below with a polymeric diol compound described below, and then reacting this with a chain extender and a reaction terminator described below can be suitably used.

[0026] Examples of the organic diisocyanate compound include aromatic diisocyanate compounds such as tolylene diisocyanate, alicyclic diisocyanate compounds such as 1,4-cyclohexane diisocyanate, isophorone diisocyanate, and dicyclohexylmethane-4,4-diisocyanate (hydrogenated MDI), aliphatic diisocyanate compounds such as hexamethylene diisocyanate, and aromatic aliphatic diisocyanate compounds such as α,α,α',α'-tetramethylxylylene diisocyanate. These organic diisocyanate compounds can be used alone or in combination of two or more. Among them, alicyclic diisocyanate compounds, aliphatic diisocyanate compounds, and aromatic aliphatic diisocyanate compounds are more preferred.

[0027] Examples of the polymer diol compound include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, polyether diol compounds such as alkylene oxide adducts of bisphenol A with ethylene oxide and propylene oxide, polyester diols obtained by condensation reaction of one or more dibasic acids such as adipic acid, sebacic acid, and phthalic anhydride with one or more glycols such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, and 3-methyl-1,5-pentanediol, polyester diol compounds such as polycaprolactone diols, etc. These polymer diol compounds can be used alone or in combination of two or more. In addition to the above-mentioned polymeric diol compounds, one or more of alkanediols such as 1,4-pentanediol, 2,5-hexanediol, and 3-methyl-1,5-pentanediol, and low molecular weight diol compounds such as ethylene glycol, propylene glycol, 1,4-butanediol, and 1,3-butanediol can be used in combination. The polymer diol compound preferably has a number average molecular weight of 1,000 to 8,000, more preferably 1,000 to 5,500, and even more preferably 1,000 to 4,000. Moreover, as the polymer diol compound, one containing 3-methyl-1,5-pentylene adipate diol can be selected.

[0028] The polyurethane polyurea resin may contain a chain extender and a reaction terminator.

[0029] The chain extender may be any of the known chain extenders used in polyurethane polyurea resins as binders for printing ink compositions. Examples of the chain extender include, among polyamine compounds, aliphatic diamines such as ethylenediamine, propylenediamine, tetramethylenediamine, and hexamethylenediamine; alicyclic diamines such as isophoronediamine and 4,4'-dicyclohexylmethanediamine; aromatic diamines such as toluylenediamine; aromatic aliphatic diamines such as xylylenediamine; diamines having a hydroxyl group such as N-(2-hydroxyethyl)ethylenediamine (aminoethylethanolamine), N-(2-hydroxyethyl)propylenediamine, and N,N'-di(2-hydroxyethyl)ethylenediamine; and diol compounds such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, and triethylene glycol.

[0030] The reaction terminator is preferably one which introduces a primary amino group and / or a secondary amino group at the terminal. Examples of polyamine compounds include aliphatic diamines such as ethylenediamine, propylenediamine, tetramethylenediamine, and hexamethylenediamine; alicyclic diamines such as isophoronediamine and 4,4'-dicyclohexylmethanediamine; polyamines such as diethylenetriamine and triethylenetetratriamine; aromatic diamines such as toluylenediamine; aromatic aliphatic diamines such as xylenediamine; and diamines having a hydroxyl group such as N-(2-hydroxyethyl)ethylenediamine (aminoethylethanolamine) and N-(2-hydroxyethyl)propylenediamine.

[0031] When reacting the organic diisocyanate compound with the polymer diol compound, the use ratio of each is preferably such that the equivalent ratio of isocyanate groups:hydroxyl groups (isocyanate index) is usually within the range of 1.2:1.0 to 3.0:1.0.

[0032] A catalyst can be used in the reaction between the organic diisocyanate compound and the polymer diol compound. Examples of the catalyst include titanium compounds such as dibutyltitanium dichloride, tetrabutyltitanium, and butoxytitanium trichloride, dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, tributyltin acetate, tributyltin chloride, triethyltin ethoxide, and tributary tin compounds. Examples of suitable tin compounds include tin compounds such as dibutyltin ethoxide, dioctyltin oxide, tributyltin trichloroacetate, and tin 2-ethylhexanoate; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; amine compounds such as 1,8-diazabicyclooctane and dimethylaminopyridine; and further, iron 2-ethylhexanoate, iron acetylacetonate, cobalt benzoate, cobalt 2-ethylhexanoate, zinc naphthenate, zinc 2-ethylhexanoate, and zirconium naphthenate.

[0033] The polyurethane polyurea resin preferably has a weight average molecular weight of 10,000 to 70,000, and more preferably 20,000 to 60,000. The weight average molecular weight is measured, for example, as a polystyrene equivalent value by gel permeation chromatography (GPC).

[0034] From the viewpoint of lamination strength and adhesiveness to the film, the content of the polyurethane resin is preferably 5 to 60 mass % in solid content relative to the total solid content mass of the flexible packaging laminate printing ink composition, and more preferably 20 to 55 mass %.

[0035] (Polymerized rosin ester) The flexible packaging laminate printing ink composition of the present invention contains a polymerized rosin ester. The polymerized rosin ester includes polymerized rosin ester A having an acid value of 50 mgKOH / g or less and a softening point of 95°C to 165°C. By incorporating a specific amount of polymerized rosin ester A having an acid value and softening point within the above ranges, it is possible to obtain a printed material that has excellent lamination strength and adhesion to the film.

[0036] The polymerized rosin ester A has an acid value of 50 mgKOH / g or less. The polymerized rosin ester A preferably has an acid value of 20 mgKOH / g or less. In this specification, the acid value is a theoretical acid value calculated arithmetically from the amount of potassium hydroxide in milligrams theoretically required to neutralize 1 g of resin.

[0037] The polymerized rosin ester A has a softening point of 95°C to 165°C. The polymerized rosin ester A preferably has a softening point of 115 to 160°C. In this specification, the softening point is measured in accordance with ASTM E28-92.

[0038] The polymerized rosin ester is an ester resin derived from rosin, and is preferably one obtained by esterifying polymerized rosin with glycerin or pentaerythritol. The polymerized rosin is a derivative containing a dimerized resin acid derived from rosin, and any known rosin or rosin derivative can be used. These can be used alone or in combination.

[0039] Examples of the rosin include gum rosin, tall oil rosin, wood rosin, etc. Generally, rosin is an amber-colored amorphous resin obtained from pine trees, and since it is obtained naturally, it is a mixture, but it may be used after being isolated into its constituent components, namely abietic acid, neoabietic acid, palustric acid, pimaric acid, isopimaric acid, sandaracopimaric acid, and dehydroabietic acid, and these are also defined as rosin in this specification.

[0040] The content of the polymerized rosin ester A is 0.2% by mass to 5.5% by mass based on the total solid content mass of the flexible packaging laminate printing ink composition. By ensuring that the content of the polymerized rosin ester A is within the above range, it is possible to provide storage stability while imparting extrusion lamination strength to OPP (oriented polypropylene) films, PET (polyethylene terephthalate) films, and NY (nylon) films, as well as adhesion to OPP films. The content of the polymerized rosin ester A is preferably 0.7% by mass to 5.0% by mass based on the total solid content mass of the flexible packaging laminate printing ink composition. As long as the content of polymerized rosin ester A is satisfied, a polymerized rosin ester that does not satisfy the requirements of an acid value of 50 mgKOH / g or less and a softening point of 95°C to 165°C (polymerized rosin ester other than polymerized rosin ester A) may be contained.

[0041] In addition to the polymerized rosin ester, polymerized rosin may be contained. The content of the polymerized rosin is preferably 0.25% by mass to 2.5% by mass based on the total solid content mass of the flexible packaging laminate printing ink composition.

[0042] (others) The flexible packaging laminate printing ink composition of the present invention may contain water and a solvent.

[0043] Examples of the solvent that can be used include toluene, ketone-based organic solvents (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ester-based organic solvents (e.g., methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, isobutyl acetate, etc.), alcohol-based organic solvents (methanol, ethanol, n-propanol, isopropanol, butanol, etc.), and hydrocarbon-based solvents (toluene, methylcyclohexane, etc.). In consideration of environmental issues and the printability and drying properties of the ink, it is preferable to use a mixed solvent of an ester-based organic solvent and an alcohol-based organic solvent as the organic solvent for the laminate printing ink composition for flexible packaging during printing, in which the ratio of the ester-based organic solvent / the alcohol-based organic solvent is in the range of 50 / 50 to 95 / 5, and it is more preferable to use the mixed solvent in which the ratio of the ester-based organic solvent / the alcohol-based organic solvent is in the range of 60 / 40 to 85 / 15. In addition, the mixed solvent may be mixed in such a ratio that the alcohol-based organic solvent is the main component, if necessary. For example, a mixed solvent of an ester-based organic solvent and an alcohol-based organic solvent may be used in such a ratio that the ester-based organic solvent / alcohol-based organic solvent is 5 / 95 to 50 / 50.

[0044] The flexible packaging laminate printing ink composition of the present invention may contain additives. Examples of the additives include various additives such as antifoaming agents, tackifiers, crosslinking agents, lubricants, antiblocking agents, antistatic agents, and surfactants. The content of the additives is about 0.01% by mass to 5% by mass relative to the total mass of the flexible packaging laminate printing ink composition.

[0045] (Method for producing a laminate printing ink composition for flexible packaging) The flexible packaging laminate printing ink composition of the present invention can be produced by using the above-mentioned various materials in various dispersing and kneading devices that have been generally used in the past. The flexible packaging laminate printing ink composition of the present invention has a viscosity of 10 to 1,000 mPa s. When printing by gravure printing, it is preferable to dilute it with an organic solvent so that the viscosity is appropriate depending on the printing conditions at the ambient temperature during printing, specifically, until the Zahn cup No. 3 outflow time is 12 to 23 seconds / 25°C, or about 14 to 16 seconds / 25°C in high-speed printing.

[0046] (Storage stability) The flexible packaging laminate printing ink composition of the present invention has excellent storage stability. The storage stability can be evaluated by the following method. The flexible packaging laminate printing ink composition is collected in a glass bottle and stored at an ambient temperature of 60°C for 14 days, after which the flexible packaging laminate printing ink composition is visually inspected. If no separation of the components is observed, the composition is deemed to have excellent storage stability.

[0047] <Printed material> The printed matter of the present invention is obtained by printing the flexible packaging laminate printing ink composition of the present invention on a flexible packaging substrate.

[0048] Examples of the above-mentioned flexible packaging substrate include polyester films such as polyethylene terephthalate (PET) film, polyolefin films such as polyethylene (PE) film, oriented polypropylene (OPP) film, and non-oriented polypropylene (CPP) film, and resin films such as polyamide films such as nylon (NY) film, the above-mentioned resin films having a metal layer such as aluminum, and the above-mentioned resin films having a transparent vapor deposition layer.

[0049] The printed matter of the present invention can be obtained, for example, by printing the flexible packaging laminate printing ink composition of the present invention on the flexible packaging substrate by gravure printing, followed by drying with a dryer.

[0050] A resin film or the like can be laminated by various methods on the side of the printed matter of the present invention on which the laminate printing ink composition for flexible packaging is printed to form a sealant layer, thereby obtaining a laminate for a packaging bag or the like. The lamination process may be an extrusion lamination method in which a molten polymer is laminated onto the surface of a printed material, with or without applying an anchor coating agent, or a dry lamination method in which an adhesive is applied onto the surface of a printed material, and then a film-like polymer is laminated.

[0051] The above-mentioned extrusion lamination method is a method in which a molten polymer is laminated on the surface of a printed material containing a layer of a printing ink composition by using a known extrusion laminator, after or without coating an anchor coating agent such as a titanium-based, urethane-based, imine-based or polybutadiene-based agent as necessary, and further, the molten resin can be laminated in a sandwich shape with other materials as an intermediate layer.

[0052] As the molten polymer used in the above extrusion lamination method, conventionally used resins such as low density polyethylene, ethylene-vinyl acetate copolymer, polypropylene, etc. can be used.

[0053] The dry lamination method is a method in which an adhesive such as a urethane-based or isocyanate-based adhesive is applied to the surface of a layer formed from a laminate printing ink composition, and then a resin film is laminated thereon using a known dry laminating machine. In particular, to obtain a packaging material (laminate) for retort use, aluminum foil can be sandwiched between the flexible packaging substrate and the resin film to be laminated. Such a laminated product (laminate) can be used for boiling and retort use after being made into a bag and filled with the contents.

[0054] Examples of the resin film include oriented and unoriented polyolefins such as polyethylene and polypropylene, polyester, nylon, cellophane, vinylon, etc. Furthermore, with regard to these resin films, films obtained by processing in advance such as coating or kneading an antifogging agent, or surface coating or kneading a matting agent can also be used. As the resin film, films in which a barrier layer formed by depositing metal or coating a barrier resin on various printing plastic films can be used.

[0055] (Physical properties of printed matter) The printed matter of the present invention has excellent extrusion lamination strength to OPP films, PET films, and NY films. The extrusion laminate strength can be evaluated by the following method.

[0056] 100 parts by mass of the flexible packaging laminate printing ink composition is diluted with a mixed solvent (ethyl acetate / propyl acetate / isopropyl alcohol = 50 / 25 / 25, mass ratio) and the viscosity is adjusted to 15 seconds using Zahn Cup No. 3 manufactured by Rigo Co., Ltd. The diluted laminate printing ink composition for flexible packaging is printed on the treated surface of various films (OPP film, PET film, NY film) using a gravure printing machine under the following conditions, and dried to obtain a print. (Printing method / printing conditions) Printing room environment: Temperature 25°C, humidity 50% Coating machine: Gravure printing machine Coating speed: 150m / min Printing plate: Direct 175 lines, 28μm, solid plate Drying temperature: 55℃

[0057] The various films used are as follows: OPP film: Corona discharge treated biaxially oriented polypropylene film (P-2161, Toyobo Co., Ltd.) 1. Thickness: 25μm PET film: Polyethylene terephthalate film (E-5102, Toyobo Co., Ltd.) with corona discharge treatment on one side, thickness 12 μm NY film: Nylon film (N-1102, manufactured by Toyobo Co., Ltd.), thickness 15 μm

[0058] For each printed material, a polyethyleneimine-based anchor coating agent (Epomin P-1000, Nippon Shokubai Co., Ltd.) was used for the OPP film and PET film, and an isocyanate-based anchor coating agent (Takelac A-3210 and Takenate A-3070, Mitsui Chemicals, Inc.) was used for the PET film and NY film, and molten polyethylene was laminated using an extrusion laminator to obtain a laminated product. These laminated products are left at 40° C. for 1 day and then cut to a width of 15 mm, and the T-peel strength is measured as the extrusion laminate strength using a peel tester (manufactured by Yasuda Seiki Seisakusho).

[0059] For OPP film (using a polyethyleneimine-based anchor coating agent), if the peel strength is 100 g / 15 mm or more, it is judged to have extremely excellent extrusion laminate strength, and if the peel strength is 50 g / 15 mm or more and less than 100 g / 15 mm, it is judged to have excellent extrusion laminate strength.

[0060] For PET film (using a polyethyleneimine-based anchor coating agent), if the peel strength is 200 g / 15 mm or more, it is judged to have extremely excellent extrusion laminate strength, and if the peel strength is 120 g / 15 mm or more and less than 200 g / 15 mm, it is judged to have excellent extrusion laminate strength.

[0061] For PET film (using an isocyanate-based anchor coating agent), if the peel strength is 500 g / 15 mm or more, it is judged to have extremely excellent extrusion laminate strength, and if the peel strength is 300 g / 15 mm or more and less than 500 g / 15 mm, it is judged to have excellent extrusion laminate strength.

[0062] For NY film (using an isocyanate-based anchor coating agent), if the peel strength is 500 g / 15 mm or more, it is judged to have extremely excellent extrusion laminate strength, and if the peel strength is 300 g / 15 mm or more and less than 500 g / 15 mm, it is judged to have excellent extrusion laminate strength.

[0063] The printed matter of the present invention has excellent adhesion to OPP films. Adhesion can be evaluated by the following method.

[0064] 100 parts by mass of the flexible packaging laminate printing ink composition is diluted with a mixed solvent (ethyl acetate / propyl acetate / isopropyl alcohol = 50 / 25 / 25, mass ratio) and the viscosity is adjusted to 15 seconds using Zahn Cup No. 3 manufactured by Rigo Co., Ltd. The diluted laminate printing ink composition for flexible packaging is printed on the treated surface of the OPP film using a gravure printing machine, and then dried to obtain a print. The printing method, printing conditions, and OPP film used were the same as those used in the evaluation method for extrusion lamination strength.

[0065] Cellophane tape (LP-12, manufactured by Nichiban Co., Ltd.) is applied to the printed surface of the printed matter (the surface printed with the laminate printing ink composition for flexible packaging), and the evaluation is based on the degree to which the printed film peels off from the OPP film when the tape is quickly peeled off. If the percentage of the area of ​​the printed ink that has peeled off from the OPP film is less than 5% of the area of ​​the printed surface where cellophane tape is applied, it is determined to have excellent adhesion. EXAMPLES

[0066] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" means "% by mass" and "parts" means "parts by mass".

[0067] The materials used in preparing the flexible packaging laminate printing ink compositions of the Examples and Comparative Examples are as follows. <Pigments> Titanium oxide (rutile type titanium oxide, silica alumina treatment, average particle size 0.3 μm) PB15:4 (CI Pigment Blue 15:4) <Polymerized rosin ester> (Polymerized rosin ester A) Polymerized rosin ester 1 (acid value 10-20mgKOH / g, softening point 100-110℃) Polymerized rosin ester 2 (acid value 35-50mgKOH / g, softening point 95-105℃) Polymerized rosin ester 3 (acid value 16mgKOH / g or less, softening point 117℃~127℃) Polymerized rosin ester 4 (acid value 20mgKOH / g or less, softening point 120℃~130℃) Polymerized rosin ester 5 (acid value 10-16mgKOH / g, softening point 130℃-140℃) Polymerized rosin ester 6 (acid value 10-16mgKOH / g, softening point 150℃-165℃) (Polymerized rosin ester other than polymerized rosin ester A) Polymerized rosin ester 7 (acid value 10-25mgKOH / g, softening point 168℃-173℃) Polymerized rosin ester 8 (acid value 0.7-7mgKOH / g, softening point 82-88℃) Polymerized rosin ester 9 (acid value 115-130mgKOH / g, softening point 153-165℃) (polymerized rosin) Polymerized rosin (Dimalex resin, manufactured by Rika Hercules) (Mixed Solvent) Mixed solvent [ethyl acetate / propyl acetate / IPA (isopropyl alcohol) = 50 parts by weight / 25 parts by weight / 25 parts by weight] (water) Water (purified water)

[0068] (Production of Polyurethane Resin A) A four-neck flask equipped with a stirrer, a cooling tube, and a nitrogen gas inlet tube was charged with 100 parts by mass of polypropylene glycol having a number average molecular weight of 2,000 and 16.7 parts by mass of isophorone diisocyanate, and reacted at 90 to 100°C for 6 hours while introducing nitrogen gas. After adding 210.8 parts by mass of propyl acetate and 70.3 parts by mass of isopropyl alcohol, the mixture was cooled to near room temperature, and a mixture of 3.5 parts by mass of isophoronediamine and 0.4 parts by mass of aminoethylethanolamine was added and stirred for 20 minutes to obtain polyurethane resin A (solid content 30% by mass).

[0069] (Production of Polyurethane Resin B) A four-neck flask equipped with a stirrer, a cooling tube, and a nitrogen gas inlet tube was charged with 50 parts by mass of polypropylene glycol having a number average molecular weight of 2,000, 50 parts by mass of polyester polyol (Curapol, manufactured by Kuraray Co., Ltd.) having a number average molecular weight of 2,000 which is a condensate of 3-methyl-1,5-pentanediol and adipic acid, and 16.7 parts by mass of isophorone diisocyanate, and the mixture was reacted at 90 to 100°C for 6 hours while introducing nitrogen gas. After adding 210.8 parts by mass of propyl acetate and 70.3 parts by mass of isopropyl alcohol, the mixture was cooled to near room temperature, and a mixture of 3.5 parts by mass of isophoronediamine and 0.4 parts by mass of aminoethylethanolamine was added and stirred for 20 minutes to obtain polyurethane resin B (solid content 30% by mass).

[0070] (Production of polyurethane resin C) A four-neck flask equipped with a stirrer, a cooling tube, and a nitrogen gas inlet tube was charged with 100 parts by mass of a polyester polyol (Kurapol, manufactured by Kuraray Co., Ltd.) having a number average molecular weight of 2,000, which is a condensate of 3-methyl-1,5-pentanediol and adipic acid, and 16.7 parts by mass of isophorone diisocyanate, and the reaction was carried out at 90 to 100°C for 6 hours while introducing nitrogen gas. After adding 210.8 parts by mass of propyl acetate and 70.3 parts by mass of isopropyl alcohol, the mixture was cooled to near room temperature, and a mixture of 3.5 parts by mass of isophoronediamine and 0.4 parts by mass of aminoethylethanolamine was added and stirred for 20 minutes to obtain polyurethane resin C (solid content 30% by mass).

[0071] (Examples 1 to 12, Comparative Examples 1 to 6) The pigment and polyurethane resin were kneaded using a paint conditioner (manufactured by Red Devil Co., Ltd.). Thereafter, rosin ester and / or dimerized rosin, antifoaming agent, water, and mixed solvent were added to obtain a laminate printing ink composition for flexible packaging. The materials used in each of the examples and comparative examples and their contents are shown in Table 1.

[0072] <Storage stability> Each flexible packaging laminate printing ink composition was placed in a glass bottle and stored at an ambient temperature of 60°C for 14 days. The storage stability of the flexible packaging laminate printing ink composition was then visually confirmed and evaluated according to the following criteria. The results are shown in Table 1. ○: No separation of components observed. ×: Separation of components is observed.

[0073] <Creating printed materials> 100 parts by mass of each flexible packaging laminate printing ink composition was diluted with a mixed solvent (ethyl acetate / propyl acetate / isopropyl alcohol = 50 / 25 / 25, mass ratio), and the viscosity was adjusted to 15 seconds using Zahn Cup No. 3 manufactured by Rigo Co., Ltd. The diluted flexible packaging laminate printing ink composition was printed on the treated surfaces of various films (OPP film, PET film, NY film) using a gravure printing machine under the following conditions, and dried to obtain prints. (Printing method / printing conditions) Printing room environment: Temperature 25°C, humidity 50% Coating machine: Gravure printing machine Coating speed: 150m / min Printing plate: Direct 175 lines, 28μm, solid plate Drying temperature: 55℃

[0074] The following films were used. OPP film: Corona discharge treated biaxially oriented polypropylene film (P-2161, Toyobo Co., Ltd.) 1. Thickness: 25μm PET film: Polyethylene terephthalate film (E-5102, Toyobo Co., Ltd.) with corona discharge treatment on one side, thickness 12 μm NY film: Nylon film (N-1102, manufactured by Toyobo Co., Ltd.), thickness 15 μm

[0075] <Extrusion laminate strength> For each printed material, a polyethyleneimine-based anchor coating agent (Epomin P-1000, Nippon Shokubai Co., Ltd.) was used for the OPP film and PET film, and an isocyanate-based anchor coating agent (Takelac A-3210 and Takenate A-3070, Mitsui Chemicals, Inc.) was used for the PET film and NY film, and molten polyethylene was laminated using an extrusion laminator to obtain a laminated product. These laminated products were left at 40°C for 1 day and then cut to a width of 15 mm, and the T-peel strength was measured as the extrusion laminate strength using a peel tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) and evaluated according to the following criteria. The results are shown in Table 1. OPP film (using polyethyleneimine anchor coating agent (Imine AC)) ◎: 100g / 15mm or more ○: 50g / 15mm or more, less than 100g / 15mm ×: Less than 50g / 15mm PET film (polyethyleneimine anchor coating agent (imine AC) used) ◎:200g / 15mm or more ○: 120g / 15mm or more, less than 200g / 15mm ×: Less than 120g / 15mm PET film (using isocyanate anchor coating agent (isocyanate AC)) ◎: 500g / 15mm or more ○: 300g / 15mm or more and less than 500g / 15mm ×: Less than 300g / 15mm NY Film (using isocyanate anchor coating agent (Isocyanate AC)) ◎: 500g / 15mm or more ○: 300g / 15mm or more and less than 500g / 15mm ×: Less than 300 g / 15 mm

[0076] <Adhesion to OPP film> 100 parts by mass of each laminate printing ink composition for flexible packaging was diluted with a mixed solvent (ethyl acetate / propyl acetate / isopropyl alcohol = 50 / 25 / 25, mass ratio), and the viscosity was adjusted to 15 seconds using a Zahn cup No. 3 manufactured by the company. Using a gravure printing machine on the treated surface of the OPP film, the diluted laminate printing ink composition for flexible packaging was printed and dried to obtain a printed matter. Note that the printing method, printing conditions, and the OPP film used are the same as those in the evaluation method of the extrusion lamination strength.

[0077] A cellophane tape (LP-12, manufactured by Nichiban Co., Ltd.) was attached to the printed surface (the surface printed with the laminate printing ink composition for flexible packaging) of each printed matter, and the degree of peeling of the printed film from the OPP film when this was rapidly peeled off was evaluated according to the following criteria. The results are shown in Table 1. 〇: The ratio of the area where the printed ink peeled off from the OPP film to the area of the portion where the cellophane tape was attached to the printed surface is less than 5%. ×: The ratio of the area where the printed ink peeled off from the OPP film to the area of the portion where the cellophane tape was attached to the printed surface is 5% or more.

[0078]

Table 1

[0079] As shown in Table 1, in a laminate printing ink composition for flexible packaging containing a pigment, a polyurethane resin, and a polymerized rosin ester, by containing a polymerized rosin ester A having an acid value and a softening point in a specific range, and further setting the content of the polymerized rosin ester A in a specific range, it was confirmed that a laminate printing ink composition for flexible packaging can be obtained which has excellent storage stability, excellent extrusion lamination strength with respect to OPP film, PET film, and NY film, and also excellent adhesion to OPP film, and a printed matter can be obtained.

[0080] The present specification discloses the following:

[0081] The present disclosure (1) is a laminate printing ink composition for flexible packaging, comprising a pigment, a polyurethane resin, and a polymerized rosin ester, wherein the polymerized rosin ester comprises polymerized rosin ester A having an acid value of 50 mgKOH / g or less and a softening point of 95°C to 165°C, and the content of the polymerized rosin ester A is 0.2% by mass to 5.5% by mass relative to the total solids mass of the flexible packaging laminate printing ink composition. The present disclosure (2) is the laminate printing ink composition for flexible packaging according to the present disclosure (1), wherein the polymerized rosin ester A has an acid value of 20 mgKOH / g or less. The present disclosure (3) is the flexible packaging laminate printing ink composition according to the present disclosure (1) or (2), wherein the content of the polymerized rosin ester A is 0.7 mass% to 5.0 mass% relative to the total solid content mass of the flexible packaging laminate printing ink composition. The present disclosure (4) is a printed matter obtained by printing the flexible packaging laminate printing ink composition according to any one of the present disclosures (1) to (3) on a flexible packaging substrate. [Industrial Applicability]

[0082] The flexible packaging laminate printing ink composition of the present invention has excellent storage stability, excellent extrusion lamination strength to OPP film, PET film, and NY film, and can provide a flexible packaging laminate printing ink composition that can give a printed item that also has excellent adhesion to OPP film.

Claims

1. A laminate printing ink composition for flexible packaging comprising a pigment, a polyurethane resin, and a polymerized rosin ester, The polymerized rosin ester includes a polymerized rosin ester A having an acid value of 50 mgKOH / g or less and a softening point of 95° C. to 165° C., The content of the polymerized rosin ester A is 0.2% by mass to 5.5% by mass based on the total solid content mass of the flexible packaging laminate printing ink composition. A laminate printing ink composition for flexible packaging.

2. The flexible packaging laminate printing ink composition according to claim 1, wherein the polymerized rosin ester A has an acid value of 20 mgKOH / g or less.

3. The flexible packaging laminate printing ink composition according to claim 1 or 2, wherein the content of the polymerized rosin ester A is 0.7% by mass to 5.0% by mass based on the total solid content mass of the flexible packaging laminate printing ink composition.

4. A printed matter obtained by printing the flexible packaging laminate printing ink composition according to claim 1 or 2 on a flexible packaging substrate.

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