Printing ink composition, laminate and packaging material

Abstract

To provide a printing ink composition which enables formation of a printed layer that is excellent in non-slip property, blocking resistance and heat resistance.SOLUTION: A printing ink composition contains a binder resin (A), urethane resin beads (B), and an organic solvent (C), wherein an average particle diameter of the urethane resin beads (B) is 0.5 to 35 μm, and a glass transition temperature thereof is -40 to 40°C, and a ratio of the mass of the urethane resin beads (B) to the mass of the binder resin (A) in terms of solid content is 0.01 to 3.0.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a printing ink composition, a laminate, and a packaging material. [Background technology]

[0002] When packaging materials are manufactured using a substrate such as a plastic film, printing is performed using printing ink such as gravure ink to decorate the substrate or to ensure necessary physical properties. Printing inks used in packaging materials are required to be able to form a printed layer that has excellent physical properties such as adhesion to the substrate, blocking resistance, heat resistance, and abrasion resistance. In recent years, there has also been a demand for printing inks with non-slip properties to prevent product loads from shifting when displayed, improve workability during transportation, and prevent consumers from slipping when picking up products.

[0003] Patent Document 1 reports that the slip resistance of the formed print layer can be improved by adding a specific binder resin and a hydrocarbon wax with a penetration of 7 or more to the ink composition. Patent Document 1 also reports that the inclusion of resin beads in the ink composition can improve the printing tone transfer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-166508 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the printed layer formed from the ink composition of Patent Document 1 does not necessarily have excellent non-slip properties, blocking resistance, and heat resistance. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a printing ink composition capable of forming a printed layer that is excellent in non-slip properties, blocking resistance, and heat resistance, and a laminate and packaging material using the same. [Means for solving the problem]

[0006] The present invention has the following aspects. [1] A printing ink composition containing a binder resin (A), urethane resin beads (B), and an organic solvent (C), the urethane resin beads (B) have an average particle size of 0.5 to 35 μm and a glass transition temperature of −40 to 40° C., A printing ink composition in which the ratio of the mass of the urethane resin beads (B) to the mass of the binder resin (A) converted into solid content is 0.01 to 3.0. [2] The printing ink composition according to [1], wherein the content of the binder resin (A) in terms of solid content is 5 to 30 mass % relative to the total mass of the printing ink composition. [3] The printing ink composition according to [1] or [2], wherein the binder resin (A) contains at least one resin selected from the group consisting of polyurethane resins, vinyl chloride-vinyl acetate copolymers, (meth)acrylic resins, polyamide resins, and nitrocellulose resins. [4] The printing ink composition according to any one of [1] to [3], wherein the static friction coefficient between the printed surfaces of a printed material formed by using the printing ink composition on a plastic film to form a printed layer is 1.0 or more. [5] The printing ink composition according to any one of [1] to [4] above, further comprising a hydrocarbon wax. [6] The printing ink composition according to any one of [1] to [5] above, further comprising silica. [7] The printing ink composition according to any one of [1] to [6] above, further comprising a chlorinated polyolefin. [8] The printing ink composition according to any one of [1] to [7] above, further comprising a fatty acid amide. [9] The printing ink composition according to any one of [1] to [8], further comprising a chelating agent.

[10] The printing ink composition according to any one of [1] to [9] above, further comprising a rosin derivative.

[11] The printing ink composition according to any one of [1] to [9] above, further comprising a terpene resin.

[12] The printing ink composition according to any one of [1] to [9] above, further comprising a curing agent.

[13] The printing ink composition according to any one of [1] to [9], wherein the organic solvent (C) contains at least two solvents selected from the group consisting of ester-based solvents, ketone-based solvents, and alcohol-based solvents.

[14] The printing ink composition according to any one of [1] to [9] above, which is for gravure printing.

[15] A plastic film; a printing layer formed on the plastic film from the printing ink composition according to any one of [1] to

[14] ; A laminate comprising:

[16] A packaging material comprising the laminate described in

[15] above. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a printing ink composition capable of forming a printed layer that is excellent in non-slip properties, blocking resistance, and heat resistance, and a laminate and packaging material using the same. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described. The following embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to these embodiments. The present invention can be implemented in various forms without departing from the spirit of the present invention. In this specification, the binder resin content is always calculated as a solid content. "Solid content" refers to the non-volatile content. "Non-volatile content" refers to the components excluding volatile media such as organic solvents, and is the component that will ultimately form the printing layer (ink layer). Specifically, non-volatile content is measured in accordance with JIS K 5601-1-2:2008. In this specification, the term "printed layer" means a layer formed from a printing ink composition. In this specification, the term "printed coating film" refers to the portion of the printed layer excluding the urethane resin beads (B). In this specification, "(meth)acrylic" is meant to include both "acrylic" and "methacrylic".

[0009] [Printing ink composition] A printing ink composition according to one embodiment of the present invention (hereinafter also simply referred to as "ink composition") contains a binder resin (A), urethane resin beads (B), and an organic solvent (C). The ink composition may further contain components other than the binder resin (A), the urethane resin beads (B), and the organic solvent (C) (hereinafter also referred to as "optional components"), as necessary.

[0010] <Binder resin (A)> The binder resin (A) may be a binder resin known as a binder resin for printing ink. The binder resin (A) preferably contains at least one resin selected from the group consisting of polyurethane resins, vinyl chloride-vinyl acetate copolymers, (meth)acrylic resins, polyamide resins, and nitrocellulose resins. Each resin will be described in detail later.

[0011] The binder resin (A) preferably contains at least two types of binder resins. By combining at least two types of binder resins, a printing coating film having an excellent balance of various coating film properties can be formed. As a combination of at least two types of binder resins, a combination of a polyurethane resin and a vinyl chloride-vinyl acetate copolymer, a combination of a (meth)acrylic resin and a vinyl chloride-vinyl acetate copolymer, a combination of a polyamide resin and a nitrocellulose resin, or a combination of a polyurethane resin and a nitrocellulose resin is preferred.

[0012] The content of the binder resin (A) (in terms of solid content) is preferably 5 to 30 mass%, more preferably 6 to 27 mass%, and particularly preferably 7 to 25 mass%, relative to the total mass of the ink composition. The content of the binder resin (A) (in terms of solid content) is preferably 18 to 70 mass%, more preferably 19 to 60 mass%, and particularly preferably 20 to 54 mass%, relative to the solid content of the ink composition. When the content of the binder resin (A) is at least the above lower limit, the adhesion to the substrate and the printability of the ink composition are improved. When the content of the binder resin (A) is at most the above upper limit, the blocking resistance is improved.

[0013] The total content (in terms of solid content) of the polyurethane resin, vinyl chloride-vinyl acetate copolymer, (meth)acrylic resin, polyamide resin, and nitrocellulose resin is preferably 60% by mass or more, more preferably 70% by mass or more, and particularly preferably 80% by mass or more, based on the total mass (in terms of solid content) of the binder resin (A). The upper limit is not particularly limited, and may be 100% by mass.

[0014] When the binder resin (A) contains a polyurethane resin and a vinyl chloride-vinyl acetate copolymer, the ratio expressed as the mass of the polyurethane resin (in terms of solid content) / the mass of the vinyl chloride-vinyl acetate copolymer (in terms of solid content) (hereinafter also referred to as the "polyurethane resin / vinyl chloride-vinyl acetate copolymer ratio") is preferably 0.5 to 8, more preferably 1 to 7, and particularly preferably 1.5 to 6. When the polyurethane resin / vinyl chloride-vinyl acetate copolymer ratio is equal to or greater than the above lower limit, the adhesion to the substrate is better. When the polyurethane resin / vinyl chloride-vinyl acetate copolymer ratio is equal to or less than the above upper limit, the blocking resistance and heat resistance are better.

[0015] When the binder resin (A) contains a (meth)acrylic resin and a vinyl chloride-vinyl acetate copolymer, the ratio expressed as the mass of the (meth)acrylic resin (in terms of solid content) / the mass of the vinyl chloride-vinyl acetate copolymer (in terms of solid content) (hereinafter also referred to as the "(meth)acrylic resin / vinyl chloride-vinyl acetate copolymer ratio") is preferably 0.5 to 8, more preferably 1 to 7, and particularly preferably 1.5 to 6. When the (meth)acrylic resin / vinyl chloride-vinyl acetate copolymer ratio is equal to or greater than the above lower limit, adhesion to the substrate is superior. When the (meth)acrylic resin / vinyl chloride-vinyl acetate copolymer ratio is equal to or less than the above upper limit, blocking resistance is superior.

[0016] When the binder resin (A) contains a polyamide resin and a nitrocellulose resin, the ratio expressed as the mass of the polyamide resin (solid content equivalent) / the mass of the nitrocellulose resin (solid content equivalent) (hereinafter also referred to as the "polyamide resin / nitrocellulose resin ratio") is preferably 0.5 to 9, more preferably 0.7 to 7.5, and particularly preferably 1 to 6. When the polyamide resin / nitrocellulose resin ratio is equal to or greater than the above lower limit, the adhesion to the substrate, the kneading resistance, and the gloss are more excellent. When the polyamide resin / nitrocellulose resin ratio is equal to or less than the above upper limit, the blocking resistance, the heat resistance, and the abrasion resistance are more excellent.

[0017] When the binder resin (A) contains a polyurethane resin and a nitrocellulose resin, the ratio expressed as the mass of polyurethane resin (solid content equivalent) / the mass of nitrocellulose resin (solid content equivalent) (hereinafter also referred to as the "polyurethane resin / nitrocellulose resin ratio") is preferably 0.5 to 9, more preferably 0.6 to 7.5, and particularly preferably 0.7 to 6. When the polyurethane resin / nitrocellulose resin ratio is equal to or greater than the above lower limit, adhesion to the substrate and kneading resistance are improved. When the polyurethane resin / nitrocellulose resin ratio is equal to or less than the above upper limit, blocking resistance, heat resistance, and abrasion resistance are improved.

[0018] (Polyurethane resin) Examples of polyurethane resins in the binder resin (A) include thermoplastic polyurethane resins soluble in organic solvents obtained by reacting a polyisocyanate compound with a polyol compound. Polyurethane resins can be produced by known methods. For example, a polyurethane resin can be obtained by reacting a polyisocyanate compound with a polyol compound, and then, if necessary, reacting the resulting reaction product (urethane prepolymer) with a chain extender and a reaction terminator.

[0019] Examples of polyisocyanate compounds include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-xylylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4-diphenylether diisocyanate, 2-nitrodiphenyl-4,4-diisocyanate, 2,2-diphenylpropane-4,4-diisocyanate, 3,3-dimethyldiphenylmethane-4,4-diisocyanate, 4,4-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, and naphthylene. Examples of suitable polyisocyanate compounds include aromatic diisocyanates such as 1,4-diisocyanate, naphthylene-1,5-diisocyanate, and 3,3-dimethoxydiphenyl-4,4-diisocyanate; aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate; and alicyclic diisocyanates such as isophorone diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. Polyurethane resins may contain one type of polyisocyanate compound alone or a combination of two or more types.

[0020] Examples of polyol compounds include polyester polyols, polycarbonate polyols, polyether polyols, etc. The polyurethane resin may contain one type of polyol compound alone or a combination of two or more types.

[0021] Examples of polyester polyols include polyester polyols and polyesteramide polyols obtained by dehydration polycondensation of polycarboxylic acids with polyhydric alcohols or secondary or tertiary amines. Specific examples of polycarboxylic acids include succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, orthophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, hexahydroorthophthalic acid, naphthalenedicarboxylic acid, and trimellitic acid, as well as their acid esters and acid anhydrides, and one or more of these can be used. Specific examples of polyhydric alcohols include low molecular weight alcohols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanedimethanol, ethylene oxide or propylene oxide adducts of bisphenol A, trimethylolpropane, glycerin, and pentaerythritol; and low molecular weight amino alcohol compounds such as monoethanolamine and diethanolamine. One or more of these may be used. Specific examples of secondary and tertiary amines include low molecular weight amine compounds such as hexamethylenediamine, xylylenediamine, and isophoronediamine. One or more of these may be used. Further, examples of polyester polyols include lactone-based polyester polyols obtained by ring-opening polymerization of cyclic ester (lactone) monomers such as ε-caprolactone and γ-valerolactone using low-molecular-weight alcohol compounds and low-molecular-weight aminoalcohol compounds as initiators.

[0022] Examples of polycarbonate polyols include those obtained by dehydrochlorination of a low molecular weight alcohol compound with phosgene, and those obtained by transesterification of a low molecular weight alcohol compound with a carbonic acid diester. Examples of low molecular weight alcohol compounds include those used in the synthesis of polyester polyols. Examples of carbonic acid diesters include diethylene carbonate, dimethyl carbonate, diethyl carbonate, and diphenyl carbonate.

[0023] Examples of polyether polyols include those obtained by ring-opening polymerization of cyclic ethers (e.g., alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran) using at least one initiator selected from the group consisting of low-molecular-weight alcohol compounds, low-molecular-weight amine compounds, low-molecular-weight amino alcohol compounds, and phenols (e.g., polyoxyethylene polyols, polyoxypropylene polyols, polytetramethylene ether polyols, polyoxyethylene polyoxypropylene polyols, etc.). Examples of low-molecular-weight alcohol compounds, low-molecular-weight amine compounds, and low-molecular-weight amino alcohol compounds include those similar to those used in the synthesis of polyester polyols. Further examples include polyester ether polyols using the aforementioned polyester polyols or polycarbonate polyols as initiators.

[0024] The chain extender may be a compound having two or more functional groups (such as amino groups or hydroxyl groups) in the molecule that are reactive with isocyanate groups. Examples of the chain extender include diamine compounds such as ethylenediamine, 1,3-propylenediamine, 1,4-butylenediamine, hexamethylenediamine, isophoronediamine, and 2-ethylaminoethylamine; polyamine compounds such as diethylenetriamine and triethylenetetramine; low-molecular-weight diol compounds such as ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, and triethylene glycol; aminoethylethanolamine; and aminopropylethanolamine. The polyurethane resin may contain one type of chain extender alone or a combination of two or more types.

[0025] Examples of the reaction terminator include monoalkylamines such as n-propylamine and n-butylamine, dialkylamines such as di-n-butylamine, alkanolamines such as monoethanolamine and diethanolamine, and monoalcohols such as methanol and ethanol. The polyurethane resin may contain one type of reaction terminator alone or two or more types in combination.

[0026] The number average molecular weight of the polyurethane resin is preferably 3,000 to 50,000, more preferably 4,000 to 30,000, and particularly preferably 5,000 to 25,000. When the number average molecular weight of the polyurethane resin is at least the above lower limit, the blocking resistance and heat resistance are more excellent. When the number average molecular weight of the polyurethane resin is at most the above upper limit, the adhesion to the substrate is more excellent. In this specification, the number average molecular weight is a value calculated in terms of standard polystyrene determined by gel permeation chromatography (GPC).

[0027] The hydroxyl value of the polyurethane resin is preferably 50 mgKOH / g or less, more preferably 30 mgKOH / g or less, and particularly preferably 20 mgKOH / g or less. When the hydroxyl value of the polyurethane resin is the above upper limit or less, the blocking resistance and the stability of the ink composition are better. In this specification, the hydroxyl value is a value measured in accordance with JIS K 1557-1.

[0028] The amine value of the polyurethane resin is preferably 10 mgKOH / g or less, more preferably 5 mgKOH / g or less, and particularly preferably 3 mgKOH / g or less. When the amine value of the polyurethane resin is the above upper limit or less, the printability is more excellent. In this specification, the amine value is a value measured by neutralization titration using hydrochloric acid in accordance with JIS K 7237.

[0029] (Vinyl chloride-vinyl acetate copolymer) Vinyl chloride-vinyl acetate copolymer is a polymer obtained by polymerizing polymerizable monomers including vinyl chloride and vinyl acetate, and contains vinyl chloride units and vinyl acetate units. The vinyl chloride-vinyl acetate copolymer may contain a polymerizable monomer unit (another polymerizable monomer) other than the vinyl chloride unit and the vinyl acetate unit, as necessary. The other polymerizable monomer is not particularly limited as long as it is copolymerizable with vinyl chloride and vinyl acetate.

[0030] Examples of vinyl chloride-vinyl acetate copolymers include vinyl chloride-vinyl acetate copolymers, vinyl chloride-vinyl acetate-vinyl alcohol copolymers, vinyl chloride-vinyl acetate-(meth)acrylic acid hydroxyalkyl ester copolymers, and vinyl chloride-vinyl acetate-unsaturated dicarboxylic acid copolymers. Among these, vinyl chloride-vinyl acetate-vinyl alcohol copolymers are preferred. One type of vinyl chloride-vinyl acetate copolymer may be used alone, or two or more types may be used in combination.

[0031] The content of vinyl chloride units is preferably 50 to 98 mass %, more preferably 70 to 98 mass %, and particularly preferably 80 to 95 mass %, based on the total mass of the vinyl chloride-vinyl acetate copolymer. When the content of vinyl chloride units is equal to or greater than the above lower limit, blocking resistance is improved. When the content of vinyl chloride units is equal to or less than the above upper limit, adhesion to substrates and kneading resistance are improved.

[0032] The content of vinyl acetate units is preferably 0.1 to 20% by mass, more preferably 0.3 to 10% by mass, and particularly preferably 0.5 to 5% by mass, based on the total mass of the vinyl chloride-vinyl acetate copolymer. When the content of vinyl acetate units is equal to or greater than the lower limit, adhesion to the substrate and kneading resistance are improved. When the content of vinyl acetate units is equal to or less than the upper limit, blocking resistance is improved.

[0033] The glass transition temperature of the vinyl chloride-vinyl acetate copolymer is preferably 40 to 110°C, more preferably 50 to 100°C, and particularly preferably 60 to 90°C. When the glass transition temperature of the vinyl chloride-vinyl acetate copolymer is equal to or higher than the above lower limit, the blocking resistance and heat resistance are more excellent. When the glass transition temperature of the vinyl chloride-vinyl acetate copolymer is equal to or lower than the above upper limit, the adhesion to the substrate is more excellent.

[0034] The number average molecular weight of the vinyl chloride-vinyl acetate copolymer is preferably 10,000 to 100,000, more preferably 15,000 to 80,000, and particularly preferably 20,000 to 50,000. When the number average molecular weight of the vinyl chloride-vinyl acetate copolymer is at least the above lower limit, the blocking resistance and heat resistance are more excellent. When the number average molecular weight of the vinyl chloride-vinyl acetate copolymer is at most the above upper limit, the adhesion to the substrate is more excellent.

[0035] ((Meth)acrylic resin) The (meth)acrylic resin is a polymer obtained by polymerizing a polymerizable monomer containing a (meth)acrylic acid ester, and contains a (meth)acrylic acid ester unit. The (meth)acrylic resin may contain a polymerizable monomer unit (another polymerizable monomer) other than the (meth)acrylic acid ester unit, as necessary. The other polymerizable monomer is not particularly limited as long as it is copolymerizable with the (meth)acrylic acid ester. The (meth)acrylic resin may be modified.

[0036] Examples of (meth)acrylic resins include homopolymers of (meth)acrylic acid esters, copolymers of multiple types of (meth)acrylic acid esters, copolymers of (meth)acrylic acid esters and (meth)acrylic acid esters with other monomers, urethane-modified (meth)acrylic resins, and silicone-modified (meth)acrylic resins. One type of (meth)acrylic resin may be used alone, or two or more types may be used in combination.

[0037] Examples of (meth)acrylic acid esters include (meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, and stearyl (meth)acrylate; (meth)acrylic acid aralkyl esters such as benzyl (meth)acrylate; (meth)acrylic acid aryl esters such as phenyl (meth)acrylate and naphthyl (meth)acrylate; and (meth)acrylic acid hydroxyalkyl esters such as 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate, but are not limited thereto. The above (meth)acrylic acid esters may be used alone or in combination of two or more.

[0038] Examples of other polymerizable monomers include, but are not limited to, styrene-based monomers such as styrene, α-methylstyrene, vinyltoluene, and derivatives thereof; unsaturated carboxylic acid-based monomers such as (meth)acrylic acid, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acrylamide, methacrylamide, acrylonitrile, and methacrylonitrile. The above-mentioned other polymerizable monomers may be used alone or in combination of two or more.

[0039] The (meth)acrylic resin preferably has a hydroxyl group and is preferably a (meth)acrylic polyol. The hydroxyl value of the (meth)acrylic resin is preferably 1 to 130 mgKOH / g, more preferably 10 to 120 mgKOH / g, and particularly preferably 50 to 110 mgKOH / g. When the hydroxyl value of the (meth)acrylic resin is at least the above lower limit, the adhesion to the substrate is better. When the hydroxyl value of the (meth)acrylic resin is at most the above upper limit, the blocking resistance and the stability of the ink composition are better.

[0040] The acid value of the (meth)acrylic resin is preferably 30 mgKOH / g or less, more preferably 20 mgKOH / g or less, and particularly preferably 10 mgKOH / g or less. When the acid value of the (meth)acrylic resin is the above upper limit or less, the stability of the ink composition is superior. In this specification, the acid value is a value measured in accordance with JIS K 1557.

[0041] The glass transition temperature of the (meth)acrylic resin is preferably 5 to 100°C, more preferably 10 to 70°C, and particularly preferably 15 to 40°C. When the glass transition temperature of the (meth)acrylic resin is at least the above lower limit, the blocking resistance and heat resistance are more excellent. When the glass transition temperature of the (meth)acrylic resin is at most the above upper limit, the adhesion to the substrate is more excellent.

[0042] The weight-average molecular weight (Mw) of the (meth)acrylic resin is preferably 10,000 to 300,000, more preferably 20,000 to 280,000, and particularly preferably 40,000 to 250,000. When the weight-average molecular weight (Mw) of the (meth)acrylic resin is at least the above lower limit, the blocking resistance and heat resistance are more excellent. When the weight-average molecular weight (Mw) of the (meth)acrylic resin is at most the above upper limit, the adhesion to the substrate is more excellent. In this specification, the weight average molecular weight is a value calculated as a standard polystyrene by gel permeation chromatography (GPC).

[0043] (Polyamide resin) The polyamide resin may be, for example, a thermoplastic polyamide resin which is a polycondensation product of a polybasic acid and a polyamine and is soluble in an organic solvent. Examples of polybasic acids include adipic acid, sebacic acid, azelaic acid, phthalic anhydride, isophthalic acid, suberic acid, glutaric acid, fumaric acid, pimelic acid, oxalic acid, malonic acid, succinic acid, maleic acid, terephthalic acid, 1,4-cyclohexyldicarboxylic acid, trimellitic acid, dimer acid, hydrogenated dimer acid, etc. In addition to these polybasic acids, monocarboxylic acids such as acetic acid, propionic acid, lauric acid, palmitic acid, benzoic acid, and cyclohexanecarboxylic acid can also be used in combination. Examples of polyamines include polyamines. Examples of polyamines include aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, and methylaminopropylamine; aliphatic polyamines such as diethylenetriamine and triethylenetetramine; alicyclic polyamines such as cyclohexylenediamine and isophoronediamine; and aromatic polyamines such as xylylenediamine, phenylenediamine, and diaminodiphenylmethane. In addition to these polyamines, primary or secondary monoamines such as n-butylamine, octylamine, dielamine, monoethanolamine, monopropanolamine, diethanolamine, and dipropanolamine can also be used in combination.

[0044] Specific examples of polyamide resins include thermoplastic polyamide resins using fatty acids made from plant materials or polymerized fatty acids made from such fatty acids. Examples of fatty acids made from plant materials include tall oil, soybean oil, coconut oil, palm oil, cashew nut oil, rice bran, and cocoa beans. Examples of polymerized fatty acids include dimer acids and hydrogenated dimer acids obtained by reducing dimer acids with hydrogen. The polyamide resins may be used alone or in combination of two or more.

[0045] The weight-average molecular weight of the polyamide resin is preferably 500 to 50,000, more preferably 700 to 30,000, and particularly preferably 1,000 to 10,000. When the weight-average molecular weight of the polyamide resin is equal to or greater than the lower limit, the abrasion resistance and heat resistance are more excellent. When the weight-average molecular weight of the polyamide resin is equal to or less than the upper limit, the adhesion to and solubility in a substrate are more excellent.

[0046] The acid value of the polyamide resin is preferably 30 mgKOH / g or less, more preferably 20 mgKOH / g or less, and particularly preferably 15 mgKOH / g or less. When the acid value of the polyamide resin is the above upper limit or less, the stability of the ink composition is superior.

[0047] The amine value of the polyamide resin is preferably 30 mgKOH / g or less, more preferably 20 mgKOH / g or less, and particularly preferably 15 mgKOH / g or less. When the amine value of the polyamide resin is the above upper limit or less, the printability is more excellent.

[0048] The softening point of the polyamide resin is preferably 80 to 160° C., more preferably 85 to 150° C., and particularly preferably 90 to 140° C. When the softening point of the polyamide resin is equal to or higher than the lower limit, the heat resistance and blocking resistance are more excellent. When the softening point of the polyamide resin is equal to or lower than the upper limit, the adhesion to the substrate is more excellent. In this specification, the softening point is a value measured in accordance with JIS K 2207.

[0049] (nitrocellulose resin) As the nitrocellulose resin, those having the type and viscosity symbol specified in JIS K 6703:1995 of H1 / 8, H1 / 4, H1 / 2, H1 or H2 are preferred, those having H1 / 4, H1 / 2, H1 or H2 are more preferred, and those having H1 / 2, H1 or H2 are particularly preferred. The type is determined according to the nitrogen content in the nitrocellulose resin. If the nitrogen content is 10.7% or more and less than 11.5%, the nitrocellulose resin is classified as type L. If the nitrogen content is 11.5% or more and 12.2% or less, the nitrocellulose resin is classified as type H. The viscosity symbol is defined according to the time (fall time) it takes for a specified steel ball to fall between the marked lines in a nitrocellulose resin solution having a specified solid content concentration. In the case of a nitrocellulose resin of the above type and viscosity symbol H1 / 8, the time it takes for a steel ball to fall into a nitrocellulose resin solution with a solid content concentration of 25% by mass is 1.6 to 2.9 seconds. In the case of a nitrocellulose resin of the above type and viscosity symbol H1 / 4, the time it takes for a steel ball to fall into a nitrocellulose resin solution with a solid content concentration of 25% by mass is 3.0 to 8.9 seconds. In the case of a nitrocellulose resin of the above type and viscosity symbol H1 / 2, the time it takes for a steel ball to fall into a nitrocellulose resin solution with a solid content of 20% by mass is 3.0 to 4.9 seconds, or the time it takes for a steel ball to fall into a nitrocellulose resin solution with a solid content of 25% by mass is 9.0 to 22.0 seconds. In the case of a nitrocellulose resin of the above type and viscosity symbol H1, the time it takes for a steel ball to fall into a nitrocellulose resin solution with a solid content concentration of 20% by mass is 5.1 to 9.0 seconds. In the case of a nitrocellulose resin of the type and viscosity symbol H2, the time it takes for a steel ball to fall into a nitrocellulose resin solution with a solid content of 12.2% by mass is 1.5 to 2.5 seconds, or the time it takes for a steel ball to fall into a nitrocellulose resin solution with a solid content of 20% by mass is 15.0 to 40.0 seconds. If the nitrocellulose resin type is L, its compatibility with ink may be slightly reduced. If the nitrocellulose resin has a viscosity lower than H1 / 8, its abrasion resistance, heat resistance, and blocking resistance may be slightly reduced. If the nitrocellulose resin has a viscosity higher than H2, its adhesion to the substrate, its rubbing resistance, and the stability of the ink composition may be slightly reduced. The nitrocellulose resin may be used alone or in combination of two or more kinds.

[0050] <Urethane resin beads (B)> The urethane resin beads (B) are made by molding polyurethane resin into beads. In this embodiment, when a printed layer is formed using the ink composition, the urethane resin beads (B) are exposed from the surface of the printed coating film. The exposed urethane resin beads (B) interfere with each other, making it difficult for printed objects to slip against each other, thereby exhibiting non-slip properties.

[0051] The average particle size of the urethane resin beads (B) is 0.5 to 35 μm, preferably 1.5 to 16 μm, and particularly preferably 2 to 12 μm. When the average particle size of the urethane resin beads (B) is equal to or greater than the above lower limit, the non-slip properties are excellent. When the average particle size of the urethane resin beads (B) is equal to or less than the above upper limit, the heat resistance, blocking resistance, abrasion resistance, adhesion to substrates, and printability are excellent. In this specification, the average particle size of the urethane resin beads (B) means the particle size at 50% cumulative value (D50) in the volume-based particle size distribution, and can be determined by a laser diffraction / scattering method.

[0052] The glass transition temperature of the urethane resin beads (B) is −40 to 40° C., preferably −20 to 25° C., and particularly preferably −17 to 20° C. When the glass transition temperature of the urethane resin beads (B) is equal to or higher than the above lower limit, the heat resistance and blocking resistance are excellent. When the glass transition temperature of the urethane resin beads (B) is equal to or lower than the above upper limit, the non-slip properties are excellent.

[0053] The ratio (hereinafter also referred to as "(B) / (A)") expressed as the mass of the urethane resin beads (B) / the mass of the binder resin (A) converted into solid content is 0.01 to 3.0, preferably 0.1 to 2.0, and particularly preferably 0.3 to 1.5. When (B) / (A) is equal to or greater than the above lower limit, the non-slip properties are excellent. When (B) / (A) is equal to or less than the above upper limit, the heat resistance and printability are excellent.

[0054] <Organic solvent (C)> The organic solvent (C) may be any solvent that does not dissolve the urethane resin beads (B), and may be appropriately selected from known organic solvents. Examples include ketone solvents, hydrocarbon solvents, ester solvents, ether solvents, glycol ether solvents, and alcohol solvents, and these may be used alone or in combination.

[0055] Examples of ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Examples of hydrocarbon solvents include aromatic hydrocarbon solvents such as toluene and xylene; aliphatic hydrocarbon solvents such as n-hexane, n-heptane, and n-octane; and alicyclic hydrocarbon solvents such as cyclohexane, methylcyclohexane, and cyclooctane. Examples of the ester solvent include methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, and isobutyl acetate. Examples of the ether solvent include tetrahydrofuran, dioxane, diethyl ether, and methyl ethyl ether. Examples of glycol ether solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, and propylene glycol monomethyl ether. Examples of alcohol-based solvents include monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, and n-butanol; and polyhydric alcohols such as ethylene glycol, propylene glycol, and glycerin.

[0056] From an environmental perspective, the organic solvent (C) preferably contains substantially no toluene, and particularly preferably contains substantially no aromatic hydrocarbon solvents. That is, the ink composition preferably contains substantially no toluene, and particularly preferably contains substantially no aromatic hydrocarbon solvents. The phrase "substantially free of" means that the ink composition is not intentionally blended in. The ink composition may contain trace amounts of aromatic hydrocarbon solvents such as toluene due to contamination of raw materials, but it is preferable that the ink composition does not contain any aromatic hydrocarbon solvents.

[0057] When a polyurethane resin and a vinyl chloride-vinyl acetate copolymer are used in combination as the binder resin (A), or when a (meth)acrylic resin and a vinyl chloride-vinyl acetate copolymer are used in combination, the organic solvent (C) preferably contains at least two solvents selected from the group consisting of ester-based solvents, ketone-based solvents, and alcohol-based solvents. As a combination of at least two organic solvents, a combination of an ester-based organic solvent and an alcohol-based organic solvent, or a combination of an ester-based organic solvent, a ketone-based organic solvent and an alcohol-based organic solvent is preferred.

[0058] When the organic solvent (C) contains at least two solvents selected from the group consisting of ester-based solvents, ketone-based solvents, and alcohol-based solvents, the content of the ester-based organic solvent is preferably 5 to 80 mass% relative to the total mass of the organic solvent (C). The content of the ketone-based organic solvent is preferably 5 to 80 mass% relative to the total mass of the organic solvent (C). The content of the alcohol-based organic solvent is preferably 0 to 50 mass% relative to the total mass of the organic solvent (C).

[0059] When a polyamide resin and a nitrocellulose resin are used in combination as the binder resin (A), the organic solvent (C) preferably contains at least two solvents selected from the group consisting of hydrocarbon solvents, ester solvents, and alcohol solvents. In this case, the content of the hydrocarbon solvent is preferably 5 to 90 mass% relative to the total mass of the organic solvent (C). The content of the ester solvent is preferably 5 to 70 mass% relative to the total mass of the organic solvent (C). The content of the alcohol organic solvent is preferably 0 to 50 mass% relative to the total mass of the organic solvent (C).

[0060] When a polyurethane resin and a nitrocellulose resin are used in combination as the binder resin (A), the organic solvent (C) preferably contains at least one solvent selected from the group consisting of ester-based solvents and alcohol-based solvents. In this case, the content of the ester-based solvent is preferably 5 to 90 mass % relative to the total mass of the organic solvent (C), and the content of the alcohol-based organic solvent is preferably 0 to 50 mass % relative to the total mass of the organic solvent (C).

[0061] The content of the organic solvent (C) in the ink composition can be appropriately set in consideration of the content of the solids in the ink composition. The solid content of the ink composition is, for example, 20 to 60 mass % relative to the total mass of the ink composition.

[0062] <Optional ingredients> Examples of optional components include hydrocarbon wax, silica, chlorinated polyolefin, fatty acid amide, chelating agent, rosin derivative, terpene resin, slow-drying solvent, curing agent, pigment, pigment derivative, extender pigment, anti-settling agent, ultraviolet absorber, antioxidant, antistatic agent, leveling agent, thickener, antifoaming agent, plasticizer, dispersant, stabilizer, etc. These optional components may be used alone or in combination of two or more. The ink composition may be a so-called medium ink composition that does not contain a pigment.

[0063] (hydrocarbon wax) To further improve rub resistance, the ink composition may contain a hydrocarbon wax. Examples of hydrocarbon waxes include polyethylene wax, Fischer-Tropsch wax, paraffin wax, microcrystalline wax, and polypropylene wax. Among these, polyethylene wax and Fischer-Tropsch wax are preferred. Examples of polyethylene waxes include high-density polymerized polyethylene, low-density polymerized polyethylene, oxidized polyethylene, acid-modified polyethylene, and special monomer-modified polyethylene. Fischer-Tropsch wax is a wax produced by the Fischer-Tropsch process using carbon monoxide and hydrogen as raw materials, and has a nearly saturated, unbranched, linear molecular structure. These hydrocarbon waxes may be used alone or in combination.

[0064] The penetration (hardness) of the hydrocarbon wax at 25° C. is preferably from 0.1 to 30, more preferably from 0.1 to 28, and particularly preferably from 0.1 to 25. When the penetration (hardness) of the hydrocarbon wax is the above upper limit or less, the abrasion resistance is more excellent. In this specification, the penetration (hardness) is a value measured in accordance with JIS K 2207.

[0065] The melting point of the hydrocarbon wax is preferably 50 to 160°C, more preferably 80 to 150°C, and particularly preferably 100 to 140°C. When the melting point of the hydrocarbon wax is equal to or higher than the lower limit, the heat resistance and blocking resistance are more excellent. When the melting point of the hydrocarbon wax is equal to or lower than the upper limit, the abrasion resistance is more excellent.

[0066] When the ink composition contains a hydrocarbon wax, the content of the hydrocarbon wax is preferably 0.1 to 10 mass %, more preferably 0.2 to 8 mass %, and particularly preferably 0.3 to 5 mass %, based on the solid content of the ink composition. When the content of the hydrocarbon wax is equal to or greater than the above lower limit, the abrasion resistance is superior. When the content of the hydrocarbon wax is equal to or less than the above upper limit, the printability and heat resistance are superior.

[0067] (silica) For the purpose of imparting a matte finish and further improving blocking resistance, silica can be contained in the ink composition. Silica may be either naturally occurring or synthetic. The synthetic method may be either a dry method or a wet method. Known dry methods include the combustion method and the arc method, and known wet methods include the precipitation method and the gel method, and silica synthesized by either method may be used. Furthermore, silica may be either crystalline or amorphous, and may be either hydrophobic or hydrophilic. These silicas may be used alone or in combination of two or more types.

[0068] The average particle size of the silica is preferably 0.1 to 10 μm, more preferably 1 to 8 μm, and particularly preferably 2 to 6 μm. When the average particle size of the silica is equal to or greater than the lower limit, it is easy to obtain the effect of imparting a matte finish and the effect of further improving blocking resistance. When the average particle size of the silica is equal to or less than the upper limit, printability is more excellent. In this specification, the average particle size of silica means the particle size at 50% cumulative value (D50) in the volume-based particle size distribution, and can be determined by a laser diffraction / scattering method.

[0069] When the ink composition contains silica, the content of silica is preferably 1 to 10 mass %, more preferably 1.5 to 8 mass %, and particularly preferably 2 to 5 mass %, based on the solid content of the ink composition. When the content of silica is equal to or greater than the lower limit, it is easy to obtain the effect of imparting a matte finish and the effect of further improving blocking resistance. When the content of silica is equal to or less than the upper limit, the ink fluidity and printability are more excellent.

[0070] (chlorinated polyolefin) For the purpose of further improving adhesion to the substrate, the ink composition may contain a chlorinated polyolefin. Chlorinated polyolefins are polyolefins in which at least some of the hydrogen atoms have been substituted with chlorine atoms. The polyolefins constituting the chlorinated polyolefins are preferably homopolymers or copolymers of α-olefin-based unsaturated hydrocarbons such as polypropylene, poly-1-butene, and poly-4-methyl-1-pentene, with polypropylene being more preferred. These chlorinated polyolefins may be used alone or in combination of two or more.

[0071] The weight-average molecular weight of the chlorinated polyolefin is preferably 1,000 to 100,000, more preferably 2,000 to 80,000, and particularly preferably 3,000 to 50,000. When the weight-average molecular weight of the chlorinated polyolefin is equal to or greater than the lower limit, the adhesion to the substrate is better. When the weight-average molecular weight of the chlorinated polyolefin is equal to or less than the upper limit, the compatibility is better.

[0072] The chlorine content of the chlorinated polyolefin is preferably 10 to 60 mass%, more preferably 15 to 55 mass%, and particularly preferably 20 to 50 mass%. When the chlorine content of the chlorinated polyolefin is equal to or higher than the above lower limit, the compatibility is better. When the chlorine content of the chlorinated polyolefin is equal to or lower than the above upper limit, the adhesion to the substrate is better. The chlorine content of the chlorinated polyolefin is the proportion (mass %) of chlorine atoms relative to the total mass of the chlorinated polyolefin.

[0073] When the ink composition contains a chlorinated polyolefin, the content of the chlorinated polyolefin is preferably 0.4 to 10 mass%, more preferably 0.6 to 8 mass%, and particularly preferably 0.8 to 7 mass%, based on the solid content of the ink composition. When the content of the chlorinated polyolefin is equal to or greater than the above lower limit, adhesion to the substrate is better. When the content of the chlorinated polyolefin resin is equal to or less than the above upper limit, blocking resistance is better.

[0074] (fatty acid amides) For the purpose of further improving the releasability and blocking resistance, the ink composition may contain a fatty acid amide. Examples of fatty acid amides include saturated fatty acid monoamides such as lauric acid amide, palmitic acid amide, stearic acid amide, oleic acid amide, erucic acid amide, behenic acid amide, hydroxystearic acid amide, and N-stearyl stearic acid amide; unsaturated fatty acid monoamides such as N-oleyl palmitic acid amide, N-stearyl oleic acid amide, and N-oleyl stearic acid amide; methylene bisstearic acid amide, ethylene biscapric acid amide, ethylene bislauric acid amide, and ethylene bisstearic acid amide. Examples of the fatty acid bisamide include saturated fatty acid bisamides such as ethylene bishydroxystearamide, ethylene bisbehenamide, hexamethylene bisstearamide, hexamethylene bisbehenamide, N,N'-distearyl adipamide, and N,N'-distearyl sebacate amide; and unsaturated fatty acid bisamides such as ethylene bisoleamide, ethylene biserucamide, hexamethylene bisoleamide, N,N'-dioleyl adipamide, and N,N'-dioleyl sebacate amide. These fatty acid amides may be used alone or in combination of two or more.

[0075] When the ink composition contains a fatty acid amide, the content of the fatty acid amide is preferably 0.4 to 5 mass%, more preferably 0.6 to 4.5 mass%, and particularly preferably 0.8 to 4 mass%, based on the solid content of the ink composition. When the content of the fatty acid amide is equal to or greater than the above lower limit, the release properties and blocking resistance are improved. When the content of the fatty acid amide is equal to or less than the above upper limit, the stability of the ink composition at low temperatures is improved.

[0076] (chelating agent) For the purpose of further improving heat resistance and blocking resistance, a chelating agent may be contained in the ink composition. Examples of the chelating agent include metal chelate compounds. Examples of the metal component of the metal chelate compound include titanium, aluminum, iron, etc. Among these, titanium is preferred. Examples of titanium chelate compounds include tetraisopropyl titanate, tetra-normal-butyl titanate, butyl titanate dimer, tetra(2-ethylhexyl) titanate, tetramethyl titanate, tetrahexyl titanate, tetraheptyl titanate, tetrastearyl titanate, triethanolamine titanate, titanium acetylacetate, titanium ethylacetoacetate, titanium lactate, octylene glycol titanate, titanium acetylacetonate, titanium tetraacetylacetonate, titanium ethylacetoacetate, dodecylbenzenesulfonic acid titanium compounds, and titanium phosphate complexes. Among these, titanium acetylacetonate is preferred due to its high reactivity and its effectiveness in increasing the bond strength within the printed layer as well as the strength between the printed layer and the substrate. These chelating agents may be used alone or in combination of two or more.

[0077] When the ink composition contains a chelating agent, the content of the chelating agent is preferably 0.5 to 10 mass%, more preferably 0.8 to 8 mass%, and particularly preferably 1 to 5 mass%, based on the solid content of the ink composition. When the content of the chelating agent is equal to or greater than the above lower limit, the heat resistance and blocking resistance are more excellent. When the content of the chelating agent is equal to or less than the above upper limit, the stability and yellowing resistance of the ink composition are more excellent.

[0078] (rosin derivatives) For the purpose of further improving adhesion to the substrate and gloss, the ink composition may contain a rosin derivative. Examples of rosin derivatives include rosin-modified maleic acid resin, rosin-modified fumaric acid resin, rosin-modified phenolic resin, rosin ester, hydrogenated rosin, polymerized rosin, etc. These rosin derivatives may be used alone or in combination of two or more.

[0079] The softening point of the rosin derivative is preferably 80 to 200°C, more preferably 85 to 180°C, and particularly preferably 90 to 150°C. When the softening point of the rosin derivative is equal to or higher than the above lower limit, the blocking resistance and heat resistance are more excellent. When the softening point of the rosin derivative is equal to or lower than the above upper limit, the adhesion to the substrate is more excellent.

[0080] The acid value of the rosin derivative is preferably 350 mgKOH / g or less, more preferably 200 mgKOH / g or less, and particularly preferably 100 mgKOH / g or less. When the acid value of the rosin derivative is the above upper limit or less, the stability of the ink composition is superior.

[0081] When the ink composition contains a rosin derivative, the content of the rosin derivative is preferably 0.5 to 10 mass%, more preferably 0.8 to 8 mass%, and particularly preferably 1 to 7 mass%, based on the solid content of the ink composition. When the content of the rosin derivative is equal to or greater than the above lower limit, adhesion to the substrate and gloss are superior. When the content of the rosin derivative is equal to or less than the above upper limit, blocking resistance and heat resistance are superior.

[0082] (Terpene resin) For the purpose of further improving adhesion to the substrate, the ink composition may contain a terpene resin. Examples of terpene resins include polyterpene resins, aromatic modified terpene resins, and terpene phenol resins. Polyterpene resins are resins whose main component is a structural unit derived from a terpene monomer. Aromatic modified terpene resins are resins obtained by modifying polyterpene resins with aromatic monomers. Terpene phenol resins are resins obtained by copolymerizing terpene monomers and phenols. These terpene resins may be used alone or in combination of two or more.

[0083] The softening point of the terpene resin is preferably 80 to 200°C, more preferably 90 to 190°C, and particularly preferably 100 to 180°C. When the softening point of the terpene resin is equal to or higher than the above lower limit, the blocking resistance and heat resistance are more excellent. When the softening point of the terpene resin is equal to or lower than the above upper limit, the adhesion to the substrate is more excellent.

[0084] The acid value of the terpene resin is preferably 10 to 150 mgKOH / g, more preferably 20 to 100 mgKOH / g, and particularly preferably 30 to 80 mgKOH / g. When the acid value of the terpene resin is equal to or greater than the above lower limit, the adhesion to the substrate is superior. When the acid value of the terpene resin is equal to or less than the above upper limit, the stability of the ink composition is superior.

[0085] When the ink composition contains a terpene resin, the content of the terpene resin is preferably 0.5 to 10 mass%, more preferably 1 to 8 mass%, and particularly preferably 2 to 5 mass%, based on the solid content of the ink composition. When the content of the terpene resin is equal to or greater than the above lower limit, adhesion to the substrate is better. When the content of the terpene resin is equal to or less than the above upper limit, blocking resistance and heat resistance are better.

[0086] (slow-drying solvent) In order to reduce the residual solvent in the printed layer and to improve the leveling and gloss of the printed layer, a slow-drying solvent may be contained in addition to the organic solvent (C). A slow-drying solvent is a solvent whose evaporation rate is less than 0.1 when the evaporation rate of butyl acetate is taken as a reference value of 1. An example of a slow-drying solvent is ethylene glycol monobutyl ether (the evaporation rate is 0.08).

[0087] (hardening agent) For the purpose of further improving adhesion to the substrate, heat resistance, and abrasion resistance, the ink composition may contain a curing agent.

[0088] As the curing agent, an isocyanate-based curing agent is preferred. The isocyanate-based curing agent is a compound having two or more isocyanate groups in one molecule. Examples of the isocyanate-based curing agent include aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate (MDI), 2,2'-MDI, 2,4'-MDI, 2,4-tolylene diisocyanate (TDI), 2,6-TDI, m-xylylene diisocyanate (XDI), and 1,4-phenylene diisocyanate; isophorone diisocyanate (IPDI), 1,3-bis(isocyanatomethyl)cyclohexane (hydrogenated XDI), dicyclohexylmethane-4,4'-diisocyanate ( Examples of the isocyanate curing agent include alicyclic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), and 1-methylcyclohexane-2,4-diisocyanate (hydrogenated TDI); aliphatic diisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), and 2,4,4-trimethylhexamethylene diisocyanate; and isocyanate prepolymers such as adducts of various diisocyanates, isocyanurates of various diisocyanates, biurets of HDI, and allophanates of HDI. These isocyanate curing agents may be used alone or in combination of two or more.

[0089] When the ink composition contains a curing agent, the content of the curing agent is preferably 1 to 10 mass %, more preferably 2 to 9 mass %, and particularly preferably 3 to 8 mass %, based on the solid content of the ink composition. When the content of the curing agent is equal to or greater than the above lower limit, adhesion to the substrate, heat resistance, and abrasion resistance are improved. When the content of the curing agent is equal to or less than the above upper limit, blocking resistance and stability of the ink composition are improved.

[0090] <Static friction coefficient> The ink composition of this embodiment preferably has a static friction coefficient of 1.0 or more, more preferably 1.1 or more, and particularly preferably 1.2 or more, between the printed surfaces of a printed material in which a printing layer is formed on a plastic film using the ink composition of this embodiment. The upper limit of the static friction coefficient is not particularly limited, but is, for example, 2.0. When the static friction coefficient is equal to or greater than the above lower limit, the ink composition is useful for applications requiring non-slip properties. In this specification, the static friction coefficient is measured in accordance with JIS K 7125. Indicators of non-slip properties include the static friction coefficient, the dynamic friction coefficient, and the sliding angle, but the static friction coefficient is particularly important.

[0091] <Manufacturing method> The ink composition of this embodiment can be obtained, for example, by mixing a binder resin (A), urethane resin beads (B), an organic solvent (C), and, if necessary, optional components, and then dispersing the mixture as necessary. The method for mixing the components is not particularly limited, and the components can be mixed by various methods. The dispersion treatment method is not particularly limited, and can be carried out using a known disperser. Examples of dispersers include a paint shaker, ball mill, attritor, sand mill, bead mill, dyno mill, roll mill, ultrasonic mill, and high-pressure collision disperser. In this case, the dispersion treatment can be carried out once or multiple times using one type of disperser, or multiple times using two or more types of dispersers in combination. When the ink composition contains a curing agent, it is preferable to premix the components other than the curing agent, and then mix the resulting mixture with the curing agent just before applying the ink composition to a substrate (such as a plastic film) to form the ink composition. The time from mixing the mixture with the curing agent to applying the ink composition to a substrate varies depending on the type of curing agent, but is, for example, within 6 hours.

[0092] <Action and effect> The ink composition of the present embodiment described above contains the binder resin (A), urethane resin beads (B), and organic solvent (C), and since the (B) / (A) ratio is 0.01 to 3.0, it is possible to form a printed layer that is excellent in non-slip properties, blocking resistance, and heat resistance. Furthermore, the adhesion of the printed layer to the substrate and abrasion resistance, as well as the printability of the ink composition, are also excellent.

[0093] <Application> The ink composition of the present embodiment is used to form a print layer on a substrate. For example, the ink composition can be diluted with an organic solvent as needed, applied to a substrate, and dried to form a printed layer.

[0094] As the substrate, a plastic film is preferred because it is highly useful in that it can be imparted with non-slip properties. Examples of plastic films include polyolefin (e.g., polyethylene (PE), polypropylene (PP)), polyester (e.g., polyethylene terephthalate (PET)), polystyrene (PS), oriented polypropylene (OPP), polyamide (NY), etc. These plastic films may be used alone or in combination of two or more.

[0095] The organic solvent used to dilute the ink composition is preferably the same as the organic solvent (C) in the ink composition. The method for applying the ink composition or a diluted version thereof may be a known method, such as gravure printing, flexographic printing, brush coating, gravure coating, die coating, bar coating, spray coating, flow coating, dip coating, spin coating, curtain coating, etc. Of these, gravure printing is preferred. The drying method may be any method capable of removing the organic solvent (C) from the ink composition, and examples thereof include heat drying and natural drying. The heating temperature for heat drying is, for example, 40 to 70°C.

[0096] The average diameter of the urethane resin beads (B) in the ink composition of this embodiment is usually larger than the thickness of the printed coating film of the printed layer formed using the ink composition. The thickness of the printed coating film varies depending on the application method, but in the case of gravure printing, for example, it is about 1 to 3 μm. The thickness of the printed layer is thicker than the thickness of the printed coating film by the amount of the urethane resin beads (B), and is, for example, 2 to 8 μm. In this specification, the thickness of the printed layer is the average value measured at 10 points using a high-precision Digimatic Micrometer MDH-25MB, manufactured by Mitutoyo Corporation. The printed layer may be provided on one side or both sides of the substrate, and may be provided so as to cover the entire substrate or so as to cover a part of the substrate.

[0097] A laminate in which a printed layer is formed on a plastic film using the ink composition of this embodiment can be used, for example, as a packaging material, particularly a soft packaging material. Here, "flexible packaging" refers to packaging materials made of flexible materials, i.e., flexible packages, and is used to package food, daily necessities, etc. When the laminate is a packaging material, from the viewpoint of the usefulness of imparting non-slip properties to a plastic film, it is preferable that a printed layer formed from the ink composition of this embodiment is located on the surface of the packaging material. Here, the surface of the packaging material is the surface opposite to the surface (rear surface) that comes into contact with the packaged item when the packaged item is wrapped in the packaging material to form a package. [Example]

[0098] The present invention will be explained in more detail below by way of examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention.

[0099] [Raw materials used] The following raw materials were used: <Binder resin (A)> A1-1: Polyurethane resin (manufactured by San Nopco Ltd., product name "Sanprene IB", glass transition temperature: -38°C, hydroxyl value: 4.2 mg KOH / g). A1-2: Polyurethane resin (manufactured by San Nopco Ltd., product name "Sanprene IB", glass transition temperature: -45°C, hydroxyl value: 11.1 mgKOH / g). A2-1: (Meth)acrylic resin (manufactured by Mitsubishi Chemical Corporation, trade name "Dianal AL", glass transition temperature: 25°C, hydroxyl value: 100 mg KOH / g). A3-1: Vinyl chloride-vinyl acetate copolymer (Nissin Chemical Industry Co., Ltd., product name "Solbine", glass transition temperature: 78°C). A3-2: Vinyl chloride-vinyl acetate copolymer (Nissin Chemical Industry Co., Ltd., product name "Solbine", glass transition temperature: 76°C). A4-1: Polyamide resin (Kao Corporation, product name "Reomaid S-8200"). A5-1: Polyurethane resin (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., product name "Seikabond A-155"). A6-1: Nitrocellulose resin (manufactured by Kimia Corporation, product name "RS1 / 2", type and viscosity symbol: H1 / 2).

[0100] <Resin beads (B)> B-1: Urethane resin beads (manufactured by Negami Chemical Industrial Co., Ltd., product name "Art Pearl C-1000T", average particle size: 3 μm, glass transition temperature: -13°C). B-2: Urethane resin beads (manufactured by Negami Chemical Industrial Co., Ltd., product name "Art Pearl C-800T", average particle size: 6 μm, glass transition temperature: -13°C). B-3: Urethane resin beads (manufactured by Negami Chemical Industrial Co., Ltd., product name "Art Pearl C-400T", average particle size: 15 μm, glass transition temperature: -13°C). B-4: Urethane resin beads (manufactured by Negami Chemical Industrial Co., Ltd., product name "Art Pearl MM-120T", average particle size: 2 μm, glass transition temperature: 22°C). B-5: Urethane resin beads (manufactured by Negami Chemical Industrial Co., Ltd., product name "Art Pearl MM-110SMA", average particle size: 1 μm). B-6: Urethane resin beads (manufactured by Negami Chemical Industrial Co., Ltd., product name "Art Pearl C-300T", average particle size: 22 μm, glass transition temperature: -13°C). B-7: Urethane resin beads (manufactured by Negami Chemical Industrial Co., Ltd., product name "Art Pearl P-800T", average particle size: 6 μm, glass transition temperature: -34°C). B-8: Urethane resin beads (manufactured by Negami Chemical Industrial Co., Ltd., product name "Art Pearl CE-800T", average particle size: 6 μm, glass transition temperature: 34°C). B-9: Cross-linked methyl methacrylate resin beads (manufactured by Sekisui Chemical Co., Ltd., product name "Techpolymer MBX-5", average particle size: 5 μm). B-10: Benzoquanamine-formaldehyde condensate resin beads (manufactured by Nippon Shokubai Co., Ltd., product name "Eposter M05", average particle size: 5 μm).

[0101] <Organic solvent (C)> C-1: A mixed solvent of ethyl acetate, methyl ethyl ketone, and isopropanol in a ratio of 2:2:1 (by mass). C-2: A mixed solvent of ethyl acetate and isopropanol in a ratio of 4:1 (by mass). C-3: A mixed solvent of methylcyclohexane, n-propyl acetate, and isopropanol in a ratio of 5:3:2 (by mass). C-4: A mixed solvent of methylcyclohexane and n-propyl acetate in a ratio of 6:4 (by mass). C-5: A mixed solvent of ethyl acetate, n-propyl acetate, and isopropanol in a ratio of 6:2:2 (by mass).

[0102] <Optional ingredients> Hydrocarbon wax: Mitsui Chemicals, Inc., product name "Hiwax 220P", penetration: 13, melting point: 110°C. Silica: Manufactured by Tosoh Silica Corporation, product name "Nipsil E-220", average particle size: 4.9 μm. Chlorinated polyolefin: Manufactured by Nippon Paper Industries Co., Ltd., product name "Superchlorine 370M". Fatty acid amide S-1: Manufactured by NOF Corporation, product name "Alflo S-10". Fatty acid amide S-2: Stearic acid amide, manufactured by Nippon Fine Chemical Co., Ltd., trade name "Neutron S". Chelating agent: Titanium chelating compound, manufactured by Matsumoto Fine Chemical Co., Ltd., product name "Orgatix TC-115". Rosin derivative: Maleated rosin ester, manufactured by Harima Chemicals Co., Ltd., product name "Haritac 4740". Terpene resin: Arakawa Chemical Industries, Ltd., product name "Tamanol 803L", softening point: 150°C, acid value: 50mgKOH / g. Curing agent: Polyisocyanate (manufactured by Mitsui Chemicals, Inc., product name "Takenate D-160N"). Extender pigment: Calcium carbonate, manufactured by Shiraishi Kogyo Co., Ltd., product name "Homocal-D". Pigment: Titanium oxide, manufactured by Teika Corporation, product name "Titanix JR-600A". Plasticizer: Fuji Amide Chemical Co., Ltd., product name "Topsizer No. 3". Antifoaming agent: BYK-1751, manufactured by BYK Japan Co., Ltd. · Slow-drying solvent: Ethylene glycol monobutyl ether (butyl cellosolve).

[0103] [Examples 1 to 55] <Preparation of Ink Composition> According to the formulations shown in Tables 1 to 10, binder resin (A), resin beads (B), organic solvent (C), and optional ingredients (except for the curing agent) were mixed, and the resulting mixture was kneaded in a paint shaker, followed by mixing in a curing agent to obtain an ink composition. The curing agent was mixed in immediately before dilution in the production of the next printed matter (A). In Tables 1 to 10, the contents of components other than the organic solvent (C) are calculated as solid content. A blank cell indicates that the component is not blended.

[0104] <Creation of printed matter (A)> Printed materials were produced using an ink composition containing a polyurethane resin and a vinyl chloride-vinyl acetate copolymer as the binder resin (A), and an ink composition containing a (meth)acrylic resin and a vinyl chloride-vinyl acetate copolymer as the binder resin (A), according to the following procedure. As a substrate, a PET film (manufactured by Toyobo Co., Ltd., product name "E5102", thickness: 25 μm) having one side subjected to a corona discharge treatment was prepared. The prepared ink composition was diluted with the same organic solvent (C) as that incorporated into the ink composition so that the viscosity at 25°C measured using Zahn cup #3 was 17 seconds. The diluted ink composition was applied to the corona discharge-treated surface of a substrate using a gravure printing machine (manufactured by Matsuo Sangyo Co., Ltd., product name "K Printing Proofer") equipped with a gravure engraving plate with a mesh of 175 lines / inch (33 μm), and the resulting coating was dried with hot air at 80°C for 10 seconds to form a printed layer (thickness: 2 to 8 μm), yielding a printed matter (laminate). The resulting coating was then aged at 40°C for 48 hours.

[0105] <Creating printed matter (B)> Printed materials were prepared according to the following procedure using an ink composition containing a combination of a polyamide resin and a nitrocellulose resin as the binder resin (A), and an ink composition containing a combination of a polyurethane resin and a nitrocellulose resin. As a substrate, an OPP film (trade name "FOR", manufactured by Futamura Chemical Co., Ltd., thickness: 25 μm) having one side subjected to a corona discharge treatment was prepared. The prepared ink composition was diluted with the same organic solvent (C) as that blended into the ink composition so that the viscosity at 25°C measured using Zahn cup #3 was 17 seconds. The diluted ink composition was applied to the corona discharge-treated surface of the substrate using a gravure printing machine (manufactured by Matsuo Sangyo Co., Ltd., product name "K Printing Proofer") equipped with a gravure engraving plate with a mesh of 175 lines / inch (33 μm), and then dried with hot air at 80°C for 10 seconds to form a printed layer (thickness: 2 to 8 μm), yielding a printed matter (laminate).

[0106] <Evaluation of friction coefficient> The printed surfaces of the printed materials were placed together, and the static and dynamic coefficients of friction were measured by sliding the printed materials against each other under conditions of a 200 g load and 100 mm / min in accordance with JIS K 7125. The coefficient of friction of printed material (A) was evaluated after aging. The preferred value of the static friction coefficient is as described above, and the dynamic friction coefficient is preferably 0.5 or more, more preferably 0.6 or more.

[0107] <Slip angle evaluation> The printed surfaces of the printed materials were placed together, and the sliding angle was measured using a friction measuring instrument (manufactured by Toyo Seiki Co., Ltd., product name "Friction Measuring Instrument AN") in accordance with JIS P 8147:2010 "8 Inclination Method." The sliding angle of printed material (A) was evaluated after aging. The sliding angle is preferably 30° or more, and more preferably 35° or more.

[0108] <Evaluation of adhesion to substrate> After applying cellophane tape (manufactured by Nichiban Co., Ltd.) to the printed surface of the printed matter, the cellophane tape was quickly peeled off and the state of the printed layer remaining on the substrate was visually inspected and the adhesion to the substrate was evaluated according to the following evaluation criteria: For printed matter (A), the adhesion was evaluated after aging. 5: The ratio of the area of ​​the peeled printing layer to the total area of ​​the printing layer is 0% or more and less than 5%. 4: The ratio of the area of ​​the peeled printing layer to the total area of ​​the printing layer is 5% or more and less than 20%. 3: The ratio of the area of ​​the peeled printing layer to the total area of ​​the printing layer is 20% or more and less than 50%. 2: The ratio of the area of ​​the peeled printing layer to the total area of ​​the printing layer is 50% or more and less than 80%. 1: The ratio of the area of ​​the peeled printing layer to the total area of ​​the printing layer is 80% or more and 100% or less.

[0109] <Evaluation of blocking resistance> The printed side of a printed item is overlapped with the non-printed side of the same printed item and the load is 4kg / cm 2A load of 1000 kJ / cm was applied to the printed matter (A) and the printed matter (B) was stored in a thermostatic oven at 40°C for 24 hours. The printed and non-printed surfaces were then peeled away, and the state of adhesion of the printed layer to the non-printed surface (ink absorption) was visually confirmed. Blocking resistance was evaluated according to the following evaluation criteria. For printed matter (A), blocking resistance was evaluated before aging. 5: Ink absorption onto the non-printed surface is 0% or more and less than 10% of the total area of ​​the printed layer. 4: Ink absorption onto the non-printed surface is 10% or more but less than 20% of the total area of ​​the printed layer. 3: Ink absorption onto the non-printed surface is 20% or more but less than 50% of the total area of ​​the printed layer. 2: Ink absorption onto the non-printed surface is 50% or more but less than 80% of the total area of ​​the printed layer. 1: Ink absorption onto the non-printed surface is 80% or more and 100% or less of the total area of ​​the printed layer.

[0110] <Heat resistance evaluation 1 (printed matter (A))> The printed surface of the aged printed matter (A) was placed on a soft aluminum foil, and a heat seal tester (manufactured by Tester Sangyo Co., Ltd., product name "TP-701-C Heat Seal Tester") was used to measure the temperature at 140 to 180°C and 2 kg / cm2 on the aluminum foil. 2 After that, the printed surface was peeled off from the aluminum foil, and the state of ink absorption onto the aluminum foil was visually confirmed, and the heat resistance was evaluated according to the evaluation criteria shown below. 5: The ink did not come off even when heated to 180°C. 4: When heated to 170°C, the ink did not come off, but when heated to 180°C, the ink came off. 3: When heated to 160°C, the ink did not come off, but when heated to 170°C, the ink came off. 2: When heated to 150°C, the ink did not come off, but when heated to 160°C, the ink came off. 1: Ink removal occurred when heated below 150°C.

[0111] <Heat resistance evaluation 2 (printed matter (B))> The printed surface of the printed matter (B) was placed on a soft aluminum foil, and a heat seal tester (manufactured by Tester Sangyo Co., Ltd., product name "TP-701-C Heat Seal Tester") was used to measure the temperature at 110 to 150°C and 2 kg / cm2 on the aluminum foil. 2 After that, the printed surface was peeled off from the aluminum foil, and the state of ink absorption onto the aluminum foil was visually confirmed, and the heat resistance was evaluated according to the evaluation criteria shown below. 5: No ink was removed even when heated to 150°C. 4: When heated to 140°C, the ink did not come off, but when heated to 150°C, the ink came off. 3: When heated to 130°C, the ink did not come off, but when heated to 140°C, the ink came off. 2: When heated to 120°C, the ink did not come off, but when heated to 130°C, the ink came off. 1: Ink removal occurred when heated below 120°C.

[0112] <Evaluation of abrasion resistance> A rubbing test was conducted on the printed surface of the printed matter, using a Gakushin-type rubbing fastness tester (manufactured by Tester Sangyo Co., Ltd., product name "AB-301"), in which a load of 200 gf was applied and a black cloth (cotton No. 3-1: gold cloth No. 3) was rubbed back and forth 100 times. The appearance of the printed layer was then visually inspected, and the rub resistance was evaluated according to the following evaluation criteria. The rub resistance of printed matter (A) was evaluated after aging. 5: The area of ​​the printed layer that has migrated to the black cloth (gold cloth No. 3) is 0% or more and less than 10%. 4: The area of ​​the printed layer that has migrated to the black cloth (gold cloth No. 3) is 10% or more but less than 20%. 3: The area of ​​the printed layer that has migrated to the black cloth (gold cloth No. 3) is 20% or more but less than 50%. 2: The area of ​​the printed layer that has migrated to the black cloth (gold cloth No. 3) is 50% or more but less than 80%. 1: The area ratio of the printed layer that has migrated to the black cloth (gold cloth No. 3) is 80% or more and 100% or less.

[0113] <Evaluation of printability> The prepared ink composition was diluted with the same organic solvent (C) as that incorporated into the ink composition so that the viscosity at 25°C measured using Zahn Cup #3 was 17 seconds. The diluted ink composition was supplied to the ink pan of a five-color gravure printing press (manufactured by Fuji Machine Industry Co., Ltd.) equipped with a commercially available steel doctor blade and a plate with only non-image areas, and the plate was run idle at 150 m / min for 30 minutes. Thereafter, the occurrence of streaky stains (doctor streaks) on the plate surface was visually inspected, and the printability was evaluated according to the following evaluation criteria. 5: No doctor lines or 1-2 thin doctor lines were observed. 4: Three to five thin doctor lines were observed. 3: Six or more thin doctor lines or one or two thick doctor lines were observed. 2: Three to five thick doctor lines were observed. 1: Six or more thick doctor lines were identified.

[0114] The evaluation results are shown in Tables 1 to 10.

[0115] [Table 1]

[0116] [Table 2]

[0117] [Table 3]

[0118] [Table 4]

[0119] [Table 5]

[0120] [Table 6]

[0121] [Table 7]

[0122] [Table 8]

[0123] [Table 9]

[0124] [Table 10] [Industrial Applicability]

[0125] The printing ink composition of the present invention can form a printed layer that is excellent in non-slip properties, adhesion to a substrate, blocking resistance, heat resistance, and abrasion resistance. The printing ink composition of the present invention also has excellent printability. The printing ink composition of the present invention is particularly useful for gravure printing.

Claims

1. A printing ink composition comprising a binder resin (A), urethane resin beads (B), and an organic solvent (C), the urethane resin beads (B) have an average particle size of 0.5 to 35 μm and a glass transition temperature of −40 to 40° C., A printing ink composition in which the ratio of the mass of the urethane resin beads (B) to the mass of the binder resin (A) expressed in terms of solid content is 0.01 to 3.

0.

2. 2. The printing ink composition according to claim 1, wherein the content of the binder resin (A) in terms of solid content is 5 to 30 mass % relative to the total mass of the printing ink composition.

3. 2. The printing ink composition according to claim 1, wherein the binder resin (A) contains at least one resin selected from the group consisting of polyurethane resins, vinyl chloride-vinyl acetate copolymers, (meth)acrylic resins, polyamide resins, and nitrocellulose resins.

4. 2. The printing ink composition according to claim 1, wherein the static friction coefficient between the printed surfaces of a printed material formed by using the printing ink composition on a plastic film and a printed layer thereon is 1.0 or more.

5. 2. The printing ink composition according to claim 1, further comprising a hydrocarbon wax.

6. The printing ink composition according to claim 1, further comprising silica.

7. The printing ink composition according to claim 1, further comprising a chlorinated polyolefin.

8. 2. The printing ink composition according to claim 1, further comprising a fatty acid amide.

9. The printing ink composition according to claim 1, further comprising a chelating agent.

10. The printing ink composition according to claim 1, further comprising a rosin derivative.

11. The printing ink composition according to claim 1, further comprising a terpene resin.

12. The printing ink composition according to claim 1, further comprising a curing agent.

13. 2. The printing ink composition according to claim 1, wherein the organic solvent (C) comprises at least two solvents selected from the group consisting of ester-based solvents, ketone-based solvents, and alcohol-based solvents.

14. 2. The printing ink composition according to claim 1, which is for gravure printing.

15. A plastic film, a printing layer formed from the printing ink composition according to any one of claims 1 to 14 on the plastic film; A laminate comprising:

16. A packaging material comprising the laminate according to claim 15.

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