Coating agent for paper substrates or plastic substrates, and paper substrates, plastic substrates, containers and packaging materials having a coating layer of said coating agent

Abstract

Provided is a coating agent for a paper substrate or plastic substrate, the coating agent containing a binder resin (A), an antibacterial agent (B), and an organic solvent, wherein: the binder resin (A) is a combination selected from among a urethane-based resin / vinyl chloride-based resin, a urethane-based resin / cellulose-based resin, a polyamide-based resin / cellulose-based resin, an acrylic resin / cellulose-based resin and a vinyl chloride-based resin / cellulose-based resin; and the antibacterial agent (B) is at least one selected from the group consisting of a fatty acid metal salt, a metal complex of a heteroatom-containing ligand and a metal ion, and a metal complex of a heteroatom-containing ligand and a fatty acid metal salt.

Description

[Technical Field]

[0001] The present invention relates to a coating agent for paper or plastic substrates that can be used as gravure ink or flexographic ink for flexible packaging. [Background technology]

[0002] In recent years, there has been a demand for imparting functionality to the surfaces of various substrates, and this is necessary to improve the surface properties of plastic materials, molded products, paper substrates, film substrates, packaging materials, etc. A widely known method for imparting these functions to the surface of a substrate is to attach a polymer film or the like having various functions to the surface. However, this method requires time and effort to attach the film, and often results in insufficient adhesion to the substrate and processability, and is also expensive. On the other hand, coating is also known as a method of imparting functionality to the surface of these substrates. Coating methods are highly convenient because they can be applied to desired areas of substrates, not only before molding or processing, but also after molding or processing. However, coating methods often have inferior functionality and durability compared to films. As substrates, film substrates such as polyester films, nylon films, and polyolefin films, which are widely used particularly for food packaging and coating consumer goods, are desired to have physical functionality such as water repellency, oil repellency, stain resistance, antistatic properties, antireflection properties, and scratch resistance, as well as hygienic properties such as antibacterial properties, antifungal properties, and deodorizing properties.

[0003] On the other hand, photocatalytic systems (TiO2, etc.) and metal systems (Ag, etc.) are known as so-called antibacterial agents using compounds with antibacterial, antifungal, and deodorizing functions (for example, Patent Document 1). These metals or metal compounds are applied directly to the target object, or mixed with a binder resin to form a coating composition, which is then applied to the target object. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-182846 Summary of the Invention [Problem to be solved by the invention]

[0005] When inorganic metal compounds, which are conventional antibacterial agents, are directly applied to an object to be treated, problems arise such as a change in the color of the object, a rough feel to the touch, and reduced abrasion resistance and scratch resistance. Furthermore, even when a coating composition is prepared from an inorganic metal compound and a binder resin, the coating layer obtained from the coating composition has a cloudy color due to the inorganic metal compound, and when the binder resin is a transparent resin, the transparency is impaired. The present invention provides a coating agent for paper substrates or plastic substrates that has antibacterial properties due to an antibacterial agent of an inorganic metal compound, and also has transparency, adhesion, scratch resistance, and abrasion resistance. [Means for solving the problem]

[0006] As a result of intensive research by the present inventors to solve the above-mentioned problems, the present invention provides a coating agent for paper substrates or plastic substrates, which contains a binder resin (A) that combines two types of resins, an antibacterial agent (B), and an organic solvent, wherein the antibacterial agent (B) is in the form of a fatty acid metal salt or a metal complex.

[0007] That is, the present invention provides a coating composition comprising a binder resin (A), an antibacterial agent (B), and an organic solvent, the binder resin (A) is a combination selected from the group consisting of a urethane resin / vinyl chloride resin, a urethane resin / cellulose resin, a polyamide resin / cellulose resin, an acrylic resin / cellulose resin, and a vinyl chloride resin / cellulose resin; the antibacterial agent (B) is at least one selected from the group consisting of a fatty acid metal salt, a metal complex of a heteroatom-containing ligand and a metal ion, and a metal complex of a heteroatom-containing ligand and a fatty acid metal salt; The coating agent for paper substrates or plastic substrates is characterized in that the metal of the fatty acid metal salt, the metal of the metal complex of the heteroatom-containing compound ligand and a metal ion, and the metal of the metal complex of the heteroatom-containing compound ligand and a fatty acid metal salt are each independently lithium, sodium, potassium, rubidium, cesium, boron, magnesium, aluminum, calcium, manganese, iron, cobalt, nickel, tin, antimony, copper, silver, zinc, molybdenum, vanadium, strontium, zirconium, barium, bismuth, lead, gold, platinum, or a rare earth.

[0008] The present invention also relates to a coating agent for paper substrates or plastic substrates according to claim 1, wherein the metal of the fatty acid metal salt, the metal of the metal complex of the heteroatom-containing compound ligand and a metal ion, and the metal of the metal complex of the heteroatom-containing compound ligand and a fatty acid metal salt are each independently bismuth, neodymium, magnesium, cobalt, copper, silver, zinc, lead, yttrium, lanthanum, praseodymium, samarium, or gadolinium.

[0009] The present invention also relates to a coating agent for paper substrates or plastic substrates, wherein the fatty acid metal salt is a metal salt of a fatty acid having 1 to 22 carbon atoms.

[0010] The present invention also relates to a coating agent for paper substrates or plastic substrates, wherein the fatty acid metal salt is a metal salt of formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, 2-ethylbutyric acid, heptanoic acid, octanoic acid, 2-ethylhexanoic acid, isononanoic acid, neodecanoic acid, naphthenic acid, stearic acid, or oleic acid.

[0011] The present invention also relates to a coating agent for paper substrates or plastic substrates, wherein the heteroatom-containing ligand is one or more amine ligands selected from the group consisting of picolinic acid, 2-{[(2-dimethylamino)ethyl]methylamino}ethanol, 1,2-propanediamine, 1,2-cyclohexanediamine, monoethanolamine, diethanolamine, triethanolamine, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 2,4-dimethylimidazole, 1,4-diethylimidazole, 8-quinolinol, 5-chloro-8-quinolinol, 2,2'-bipyridyl and its derivatives, and 2,2'-[propane-1,2-diylbis(azanylylidenemethanylylidene)]diphenol and its derivatives.

[0012] The present invention also relates to a coating agent for paper substrates or plastic substrates, which contains the isocyanate compound (E).

[0013] The present invention also relates to a paper substrate or a plastic substrate coated with the coating agent.

[0014] The present invention also relates to the paper substrate or plastic substrate, which further has a printed ink layer.

[0015] The present invention also relates to containers and packaging materials using paper or plastic substrates. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a coating agent for paper substrates or plastic substrates that has antibacterial properties due to the antibacterial agent of an inorganic metal compound, and also has transparency, adhesion, scratch resistance, and abrasion resistance. DETAILED DESCRIPTION OF THE INVENTION

[0017] (Definition of words) In the present invention, all "parts" refer to "parts by mass," "total amount of coating agent" refers to the total amount of coating agent including all volatile components such as organic solvents, and "total amount of solids in coating agent" refers to the total amount of only non-volatile components, excluding volatile components.

[0018] (Binder resin (A)) The binder resin (A) used in the coating agent for paper substrates or plastic substrates of the present invention is preferably any combination selected from urethane resin / vinyl chloride resin, urethane resin / cellulose resin, polyamide resin / cellulose resin, acrylic resin / cellulose resin, or vinyl chloride resin / cellulose resin.

[0019] (urethane resin) The urethane resin is not particularly limited as long as it is a polyurethane resin obtained by reacting a polyol with a polyisocyanate. Examples of polyols that can be used include various known polyols that are commonly used in the production of polyurethane resins, and one or more of these may be used in combination. Examples of suitable polyols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, and dipropylene glycol. Saturated or unsaturated low molecular weight polyols (1) such as ethylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, and pentaerythritol; these low molecular weight polyols (1) and sebacic acid, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, and trimellitic acid. polyester polyols (2) obtained by dehydration condensation or polymerization of polycarboxylic acids such as methyl acrylate, pyromellitic acid, or their anhydrides; polyester polyols (3) obtained by ring-opening polymerization of cyclic ester compounds, for example, lactones such as polycaprolactone, polyvalerolactone, and poly(β-methyl-γ-valerolactone); polycarbonate polyols (4) obtained by reacting the low-molecular-weight polyols (1) or the like with, for example, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, or the like; polybutadiene glycols (5); glycols (6) obtained by adding ethylene oxide or propylene oxide to bisphenol A; and acrylic polyols (7) obtained by copolymerizing, in one molecule, one or more hydroxyethyl groups, hydroxypropyl acrylate, hydroxybutyl acrylate, or the like, or the corresponding methacrylic acid derivatives, with, for example, acrylic acid, methacrylic acid, or an ester thereof.

[0020] Examples of polyisocyanates include various known aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates that are generally used in the production of polyurethane resins. For example, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-2,5-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene diisocyanate, 1-isopropyl-2,4-phenylene diisocyanate, 1,3-dimethyl-2,4-phenylene diisocyanate, 1,3-dimethyl-4,6-phenylene diisocyanate, 1,4-dimethyl-2,5-phenylene diisocyanate, diethylbenzene diisocyanate, diisopropylbenzene diisocyanate, 1-methyl-3,5-diethylbenzene diisocyanate, 3 -Methyl-1,5-diethylbenzene-2,4-diisocyanate, 1,3,5-triethylbenzene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 1-methyl-naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate, 1,1-dinaphthyl-2,2'-diisocyanate Aromatic polyisocyanates such as cyanate, biphenyl-2,4'-diisocyanate, biphenyl-4,4'-diisocyanate, 3-3'-dimethylbiphenyl-4,4'-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, diphenylmethane-2,4-diisocyanate; tetramethylene diisocyanate, hexamethylene diisocyanate, etc. and aliphatic or alicyclic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di(isocyanatemethyl)cyclohexane, 1,4-di(isocyanatemethyl)cyclohexane, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, and 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate. These polyisocyanates may be used alone or in combination of two or more. Among these, these diisocyanate compounds can be used alone or in combination of two or more.

[0021] Chain extenders can also be used. Examples of chain extenders include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, and dicyclohexylmethane-4,4'-diamine, as well as amines having a hydroxyl group in the molecule, such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, and di-2-hydroxypropylethylenediamine. These chain extenders can be used alone or in combination of two or more.

[0022] Monovalent active hydrogen compounds can also be used as end-capping agents for the purpose of terminating the reaction. Examples of such compounds include dialkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol. Furthermore, when it is particularly desired to introduce carboxyl groups into the polyurethane resin, amino acids such as glycine and L-alanine can be used as reaction terminators. These end-capping agents can be used alone or in combination. The weight average molecular weight of the urethane resin is preferably 10,000 to 100,000, and more preferably in the range of 15,000 to 80,000.

[0023] A particularly preferred urethane resin is urethane resin (A) obtained by reacting a polyester polyol, which is made from a polycarboxylic acid having 7 or more carbon atoms and two or more carboxyl groups and a compound having two or more hydroxyl groups as reaction raw materials, with a polyisocyanate.

[0024] Examples of polycarboxylic acids having 7 or more carbon atoms and two or more carboxyl groups include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, and anhydrides of these acids; aliphatic dicarboxylic acids such as pimelic acid, suberic acid, azelaic acid, sebacic acid, and dimer acid; tricarboxylic acids such as trimellitic acid and anhydrides thereof; benzenetetracarboxylic acid, benzenepentacarboxylic acid, benzenehexacarboxylic acid, and anhydrides of these acids. These polybasic acids may be used alone or in combination. Among these, sebacic acid and dimer acid are preferred because they provide adhesion to a wide variety of film substrates, and these may be used alone or in combination.

[0025] The polyester polyol may contain other polycarboxylic acids as needed, and may contain any of various known polycarboxylic acids commonly used in the production of polyester polyols, and may contain one or more of these in combination, such as adipic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, and glutaric acid.

[0026] Furthermore, with the recent rise in global awareness of environmental issues, attention is being paid to raw materials derived from biomass resources such as plants, rather than petroleum-derived raw materials that contribute to global warming, and these raw materials can also be used. Examples of polycarboxylic acids derived from biomass resources include succinic acid and succinic anhydride.

[0027] Examples of the compound having two or more hydroxyl groups include glycols such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol; 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,2-butanediol, 1,3-butanediol, and 2-butyl-2- Glycols having a branched structure such as ethyl-1,3-propanediol, 1,2-propanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-isopropyl-1,4-butanediol, 2,4-dimethyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-ethyl-1,6-hexanediol, 3,5-heptanediol, and 2-methyl-1,8-octanediol; glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, and sorbitol can be used. These compounds may be used alone or in combination of two or more.

[0028] As with polycarboxylic acids, compounds having two or more hydroxyl groups can also be derived from biomass resources such as plants. Examples of compounds having two or more hydroxyl groups derived from biomass resources include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, and glycerin.

[0029] The number average molecular weight of the polyester polyol is preferably in the range of 500 to 8,000, more preferably in the range of 800 to 7,000, and even more preferably in the range of 900 to 6,000.

[0030] Furthermore, it is more preferable that the polyurethane resin contains a polyether polyol in an amount of 1 to 40% by mass relative to the polyurethane resin as a constituent component. Various known ether polyols commonly used in the production of polyurethane resins can be used as the polyether polyol, and one or more of them may be used in combination. Examples include polyether polyols of polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran, etc. It is more preferable that the number average molecular weight of the polyether polyol is 100 to 3,500.

[0031] The polyol, polyisocyanate compound, chain extender, terminal blocking agent, etc., which are optionally used in combination with the polyurethane resin used in the coating agent of the present invention, can be the same as those described above. The weight average molecular weight of the polyurethane resin is preferably within the range of 10,000 to 100,000, and more preferably within the range of 15,000 to 95,000.

[0032] The amount of these urethane resins added is preferably 0.15 to 40% by mass, more preferably 1.0 to 35% by mass, based on the total amount of the coating agent.

[0033] (Vinyl chloride resin) As a vinyl chloride resin, a vinyl chloride-vinyl acetate copolymer resin is preferred because it is versatile. There are no particular limitations on the vinyl chloride-vinyl acetate copolymer resin, so long as it is a copolymer of vinyl chloride and vinyl acetate. The weight-average molecular weight is preferably 5,000 to 100,000, and more preferably 10,000 to 70,000. In 100% by mass of the solids content of the vinyl chloride-vinyl acetate copolymer resin, the vinyl acetate monomer-derived structure is preferably 1 to 30% by mass, and the vinyl chloride monomer-derived structure is preferably 70 to 95% by mass. This improves solubility in organic solvents, and further improves adhesion to substrates, coating properties, scratch resistance, and the like. From the viewpoint of solubility in organic solvents, those containing hydroxyl groups derived from a vinyl alcohol structure are also preferred. The hydroxyl value is preferably 20 to 200 mgKOH / g. The glass transition temperature is preferably 50 to 90°C. The amount of vinyl chloride-vinyl acetate copolymer resin added is preferably 0.15 to 40% by mass, more preferably 1.0 to 35% by mass, based on the total amount of the coating agent.

[0034] (cellulose resin) Examples of cellulose-based resins include cellulose acetate propionate, cellulose acetate butyrate, and other cellulose ester resins, nitrocellulose (also known as soluble cellulose), hydroxyalkyl cellulose, and carboxyalkyl cellulose. The cellulose ester resin preferably has an alkyl group, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, and a hexyl group, and the alkyl group may further have a substituent. Of the above, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferred as cellulose-based resins. Nitrocellulose is particularly preferred. The weight-average molecular weight of the cellulose-based resin is preferably 5,000 to 200,000, more preferably 10,000 to 50,000. The glass transition temperature of the cellulose-based resin is preferably 120°C to 180°C. When used in combination with the polyurethane resin (A) of the present invention, improvements in blocking resistance, scratch resistance, and other physical properties of the ink film can be expected. Nitrocellulose (nitrocellulose) is preferably obtained as a nitric acid ester by reacting natural cellulose with nitric acid to replace three hydroxyl groups in the six-membered ring of the anhydroglucopyranose group in the natural cellulose with nitric acid groups.

[0035] The use of nitrocellulose (nitrocellulose) provides high dispersibility in pigments, and is therefore suitable for use as a coating agent for surface printing, as it can improve the strength of the printing ink film. The nitrocellulose (nitrocellulose) preferably has a nitrogen content of 10 to 13% by mass and an average degree of polymerization of 30 to 500, and more preferably has a nitrogen content of 10 to 13% by mass and an average degree of polymerization of 45 to 290.

[0036] The amount of nitrocellulose (nitrocellulose) added is preferably 0.15 to 40% by mass, more preferably 1.0 to 35% by mass, based on the total amount of the coating agent.

[0037] (Polyamide resin) The polyamide resin is, for example, a thermoplastic polyamide soluble in an organic solvent, which can be obtained by polycondensation of a polybasic acid and a polyamine. In particular, a polyamide resin containing a reaction product of an acid component containing a polymerized fatty acid and / or a dimer acid with an aliphatic and / or aromatic polyamine is preferred, and one containing a portion of primary and secondary monoamines is even more preferred. Polybasic acids used as raw materials for polyamide resins include, but are not limited to, 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, and polymerized fatty acid. Among these, polyamide resins containing a structure derived from dimer acid or polymerized fatty acid as the main component (50% by weight or more in the polyamide resin) are preferred. Here, polymerized fatty acid is obtained by, for example, the cyclization reaction of unsaturated fatty acid, and includes monobasic fatty acid, dimerized polymerized fatty acid (dimer acid), trimerized polymerized fatty acid, and the like. Fatty acids constituting dimer acid or polymerized fatty acid include those derived from natural oils such as soybean oil, palm oil, and rice bran oil, with those derived from oleic acid and linoleic acid being preferred. The polybasic acid may be used in combination with a monocarboxylic acid, such as acetic acid, propionic acid, lauric acid, palmitic acid, benzoic acid, or cyclohexanecarboxylic acid.

[0038] Examples of polyamines include polyamines and primary or secondary monoamines. Examples of polyamines used in polyamide resins include aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, and methylaminopropylamine, and aliphatic polyamines such as diethylenetriamine and triethylenetetramine. Examples of alicyclic polyamines include cyclohexylenediamine and isophoronediamine. Examples of aromatic aliphatic polyamines include xylylenediamine, and examples of aromatic polyamines include phenylenediamine and diaminodiphenylmethane. Examples of primary and secondary monoamines include n-butylamine, octylamine, diethylamine, monoethanolamine, monopropanolamine, diethanolamine, and dipropanolamine. The amount of polyamide resin added is preferably 0.15 to 40% by mass, more preferably 1.0 to 35% by mass, based on the total amount of the coating agent.

[0039] (acrylic resin) The acrylic resin is not particularly limited as long as it is a copolymer of polymerizable monomers whose main component is a (meth)acrylic acid ester. Examples of polymerizable monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, iso-octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, iso-nonyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, and phenoxyethyl (meth)acrylate. The polymerization method is also not particularly limited, and resins obtained by known methods such as bulk polymerization, solution polymerization, emulsion polymerization, and suspension polymerization can be used. The weight average molecular weight of the acrylic resin is preferably 5,000 to 200,000, and more preferably in the range of 10,000 to 100,000. The amount of acrylic resin added is preferably 0.15 to 40% by mass, more preferably 1.0 to 35% by mass, based on the total amount of the coating agent.

[0040] In the combinations selected from the group consisting of urethane resin / vinyl chloride resin, urethane resin / cellulose resin, polyamide resin / cellulose resin, acrylic resin / cellulose resin, and vinyl chloride resin / cellulose resin, the total amount of the two resins in 100% by mass of the binder resin (A) is preferably 80 to 100% by mass, and most preferably 90 to 100% by mass.

[0041] Furthermore, the mass ratio of urethane resin / vinyl chloride resin, urethane resin / cellulose resin, polyamide resin / cellulose resin, acrylic resin / cellulose resin, and vinyl chloride resin / cellulose resin is preferably 95 / 5 to 20 / 80, more preferably 90 / 10 to 50 / 50. This combination provides excellent abrasion resistance, blocking resistance, heat resistance, oil resistance, and other basic properties desired for a coating agent.

[0042] (Polyester resin) Furthermore, a polyester resin may be added as needed. The polyester resin is not particularly limited as long as it is a polyester resin obtained by reacting an alcohol with a carboxylic acid using a known esterification polymerization reaction. Examples of alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-butyl-1,3propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,2-pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4-butylenediol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, pentaerythritol, 1,4-cyclohexanediol, 1,2-cyclohexanediol, 1,4-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, spiroglycol, and isosorbide. These may be used alone or in combination of two or more. Among these, polyfunctional alcohols are preferred. Examples of carboxylic acids include formic acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, oleic acid, linoleic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, and 1,4-cyclohexanedicarboxylic acid. These may be used alone or in combination of two or more. Among these, polyfunctional carboxylic acids are preferred. The weight average molecular weight of the polyester resin is preferably 500 to 6000, more preferably 1400 to 5500.

[0043] (rosin-based resin) Furthermore, a rosin-based resin may be added as needed. The rosin-based resin is not particularly limited as long as it is a resin having a rosin skeleton, but rosin-modified maleic acid resin, rosin ester, rosin phenol, polymerized rosin, etc. are preferred. The softening point (measured by the ring and ball method) is preferably 90 to 200°C.

[0044] (hardening agent) A curing agent may be used in combination with the binder resin (A). The curing agent may be any of those commonly used in organic solvent-based gravure inks, but the most commonly used are isocyanate-based curing agents. The amount of the isocyanate compound added is preferably in the range of 0.3% by mass to 10.0% by mass, more preferably 1.0% by mass to 7.0% by mass, based on the solid content of the coating agent, from the viewpoint of curing efficiency. The binder resin (A) is preferably used in an amount of 0.15 to 50% by mass, and most preferably 1 to 40% by mass, based on the coating agent for paper substrates or plastic substrates of the present invention.

[0045] [Antibacterial agent] The antibacterial agent used in the present invention is one or more selected from the group consisting of fatty acid metal salts, metal complexes of heteroatom-containing ligands and metal ions, and metal complexes of heteroatom-containing ligands and fatty acid metal salts, wherein the metals in the fatty acid metal salts, the metal complexes of heteroatom-containing compound ligands and metal ions, and the metal complexes of heteroatom-containing compound ligands and fatty acid metal salts are each independently lithium, sodium, potassium, rubidium, cesium, boron, magnesium, aluminum, calcium, manganese, iron, cobalt, nickel, tin, antimony, copper, silver, zinc, molybdenum, vanadium, strontium, zirconium, barium, bismuth, lead, gold, platinum, or a rare earth.

[0046] The antibacterial agent takes the form of a fatty acid metal salt or metal complex, and when added to a coating composition containing a binder resin, it is thought that the antibacterial properties of the metal and the high compatibility of the fatty acid or complex ligand with organic substances impart antibacterial properties to the resulting coating layer while reducing the impact on appearance, such as the loss of transparency of the coating layer, caused by the antibacterial agent.

[0047] In the present invention, the term "antibacterial" encompasses the effect of reducing the number of bacteria, the effect of inactivating bacteria, the effect of reducing the infectivity of bacteria, and the like.

[0048] In the present invention, the target bacteria for antibacterial treatment are not particularly limited and may be either bacteria or fungi. Examples of bacteria include gram-negative bacteria such as Escherichia coli, Pseudomonas aeruginosa, Salmonella, Moraxella, and Legionella; and gram-positive bacteria such as Staphylococcus aureus and Clostridium bacteria. Examples of fungi include yeasts such as Candida, Rhodotorula, and baker's yeast; and molds such as red mold and black mold.

[0049] The antibacterial agent used in the present invention will now be described.

[0050] (Fatty acid metal salts) The fatty acid metal salt, which is an antibacterial agent used in the present invention, is, for example, a compound represented by the following general formula (1).

[0051] [ka] (In the general formula (1), R 1 is a hydrogen atom or an alkyl group having 1 to 21 carbon atoms, n1 is an integer ranging from 1 to 4, M 1 is lithium, sodium, potassium, rubidium, cesium, boron, magnesium, aluminum, calcium, manganese, iron, cobalt, nickel, tin, antimony, copper, silver, zinc, molybdenum, vanadium, strontium, zirconium, barium, bismuth, lead, gold, platinum, or a rare earth.

[0052] In the general formula (1), when n1 is an integer of 2 or more, a plurality of R 1 may be the same as or different from each other.

[0053] R 1 The alkyl group having 1 to 21 carbon atoms may be a linear alkyl group, a branched alkyl group, or may contain an alicyclic structure.

[0054] R 1 The hydrogen atom or alkyl group having 1 to 21 carbon atoms is used in the production of the fatty acid metal salt. 1It corresponds to a carboxylic acid residue obtained by removing the carboxyl group (COOH) from a carboxylic acid having 1 to 22 carbon atoms, represented by COOH. Examples of the carboxylic acid residue include formic acid residue, acetic acid residue, propionic acid residue, butanoic acid residue, pentanoic acid residue, hexanoic acid residue, 2-ethylbutyric acid residue, heptanoic acid residue, octanoic acid residue, acrylic acid residue, methacrylic acid residue, octylic acid residue (2-ethylhexanoic acid residue), neodecanoic acid residue, naphthenic acid residue, isononanoic acid residue, tung oil acid residue, tall oil fatty acid residue, coconut oil fatty acid residue, soybean oil fatty acid residue, linseed oil fatty acid residue, safflower oil fatty acid residue, dehydrated castor oil fatty acid residue, tung oil fatty acid residue, lauric acid residue, myristic acid residue, palmitic acid residue, stearic acid residue, isostearic acid residue, and oleic acid residue.

[0055] R 1 The alkyl group having 1 to 21 carbon atoms is preferably an alkyl group having 1 to 15 carbon atoms, more preferably an alkyl group having 1 to 11 carbon atoms, from the viewpoint of adhesion to substrates, which will be described later. R 1 is preferably a formic acid residue, an acetic acid residue, a propionic acid residue, a butanoic acid residue, a pentanoic acid residue, a hexanoic acid residue, a 2-ethylbutyric acid residue, a heptanoic acid residue, an octanoic acid residue, a 2-ethylhexanoic acid residue, an isononanoic acid residue, a neodecanoic acid residue, a naphthenic acid residue, a stearic acid residue, or an oleic acid residue.

[0056] M 1 is lithium, sodium, potassium, rubidium, cesium, boron, magnesium, aluminum, calcium, manganese, iron, cobalt, nickel, tin, antimony, copper, silver, zinc, molybdenum, vanadium, strontium, zirconium, barium, bismuth, lead, gold, platinum or a rare earth, preferably bismuth, neodymium, magnesium, cobalt, copper, silver, zinc, lead, yttrium, lanthanum, praseodymium, samarium or gadolinium, more preferably bismuth, neodymium, magnesium, cobalt, silver, copper, lead, yttrium, lanthanum, praseodymium, samarium or gadolinium. If the metal in the fatty acid metal salt is bismuth, neodymium, magnesium, lanthanum, gadolinium, or samarium, coloration due to the addition of an antibacterial agent can be made less likely to occur.

[0057] In the present invention, rare earth means one or more elements selected from scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), and lutetium (Lu).

[0058] n1 is M 1 is a value determined by the ionic valence of the metal atom, for example, M 1 If is boron, n1 is 3, and M 1 If is cobalt, n1 is 2.

[0059] The fatty acid metal salts used in the present invention as antibacterial agents also include fatty acid metal borate salts, which are compounds represented by the following general formula (2):

[0060] [ka] (In the general formula (2), R 2 is a hydrogen atom or an alkyl group having 1 to 21 carbon atoms, M 2 is boron, magnesium, aluminum, calcium, manganese, iron, cobalt, nickel, tin, antimony, copper, zinc, molybdenum, vanadium, strontium, zirconium, barium, bismuth, lead, gold, platinum, or a rare earth.

[0061] In the general formula (2), R 2 The alkyl group having 1 to 21 carbon atoms is R 1Similarly, in the general formula (2), M 2 The metal is M in the general formula (1). 1 It is the same as the metal.

[0062] When a fatty acid metal salt is used as the antibacterial agent in the present invention, one type of fatty acid metal salt may be used alone, or two or more types of fatty acid metal salts having different structures may be used.

[0063] The fatty acid metal salt can be produced by a known method, or a commercially available product may be used.

[0064] (metal complexes) The antibacterial agents used in the present invention, namely, a metal complex of a heteroatom-containing ligand and a metal ion and a metal complex of a heteroatom-containing ligand and a fatty acid metal salt, are compounds in which a metal ion or a fatty acid metal salt and a heteroatom-containing ligand form a complex through a coordinate bond.

[0065] The metal ions that form the metal complex with the heteroatom-containing ligand can be the same metal ions as those of the fatty acid metal salts explained as the antibacterial agent used in the present invention. As the fatty acid metal salt in which the heteroatom-containing ligand forms a metal complex, the same fatty acid metal salts as those explained as the antibacterial agent used in the present invention can be used.

[0066] The heteroatom-containing ligand that forms the metal complex may be a ligand that contains one or more heteroatoms selected from the group consisting of nitrogen, oxygen, sulfur, and phosphorus in the molecule. Examples of such heteroatom-containing ligands include N-methylmorpholine, pyridine, 1,8-diazabicyclo[5.4.0]undecene-7 (DBU), 1,5-diazabicyclo[4.3.0]nonene-5 (DBN), 1,4-diazabicyclo[2.2.2]octane (DABCO), 4-dimethylaminoamine (DMAP), dicyandiamide (DICY), tri-n-butylamine, dimethylbenzylamine, butylamine, 1,2-propanediamine, 1,2-cyclohexanediamine, octylamine, monoethanolamine, diethanolamine, triethanolamine, 2-[[(2-dimethylamino)ethyl]methylamino]ethanol, picolinic acid, 2,2'-[propane-1,2-diylbis(azanylylidenemethanylylidene)]diphenoxyethanol alcohol, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 2,4-dimethylimidazole, 1,4-diethylimidazole, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-(N-phenyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropylmethyldimethoxysilane, tetramethylammonium hydroxide, 8-quinolinol amine compounds such as 5-chloro-8-quinolinol, 2,2'-bipyridyl and its derivatives, 2,2'-[propane-1,2-diylbis(azanylylidenemethanylylidene)]diphenol and its derivatives, and 2,2'-methylenebis[6-(2h-benzotriazol-2-yl)-4-tert-octylphenol]; quaternary ammonium salts such as trioctylmethylammonium chloride and trioctylmethylammonium acetate; phosphine compounds such as trimethylphosphine, tributylphosphine, and triphenylphosphine; phosphonium salts such as tetramethylphosphonium chloride, tetraethylphosphonium chloride, tetrapropylphosphonium chloride, tetrabutylphosphonium chloride, tetrabutylphosphonium bromide, trimethyl(2-hydroxypropyl)phosphonium chloride, triphenylphosphonium chloride, and benzylphosphonium chloride; and sulfur-based compounds such as thiolactic acid, 2-aminothiophenol, and 2,2'-dithiodianiline.

[0067] The heteroatom-containing ligand is preferably one or more amine ligands selected from picolinic acid, 2-{[(2-dimethylamino)ethyl]methylamino}ethanol, 1,2-propanediamine, 1,2-cyclohexanediamine, monoethanolamine, diethanolamine, triethanolamine, imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 2,4-dimethylimidazole, 1,4-diethylimidazole, 8-quinolinol, 5-chloro-8-quinolinol, 2,2′-bipyridyl and its derivatives, and 2,2′-[propane-1,2-diylbis(azanylylidenemethanylylidene)]diphenol and its derivatives.

[0068] The heteroatom-containing ligand that forms the metal complex may be of one type alone or of two or more types that are different in structure from each other.

[0069] In the metal complex, the ratio (molar ratio) of the metal ion or fatty acid metal salt to the heteroatom-containing ligand is, for example, in the range of 0.1 to 12 moles, preferably 0.3 to 10 moles, and more preferably 0.5 to 10 moles, of the heteroatom-containing ligand per mole of the metal atom of the metal ion or fatty acid metal salt.

[0070] When the metal ion in the metal complex is an aluminum ion, the aluminum complex is preferably one or more selected from aluminum chelate compounds represented by the following general formula (3-1) and aluminum chelate compounds represented by the following general formula (3-2).

[0071] [ka] (In the general formulas (3-1) and (3-2), R 311 ~R 316 and R 321 ~R 326 are each independently an alkyl group having 1 to 22 carbon atoms or an alkoxy group having 1 to 22 carbon atoms.

[0072] R 311 ~R 316 and R 321 ~R 326 The alkylene group moiety of the alkyl group having 1 to 22 carbon atoms and the alkoxy group having 1 to 22 carbon atoms may be linear or branched, or may contain an alicyclic structure. 311 ~R 316 and R 321 ~R 326 The alkyl group and the alkylene group portion of the alkoxy group preferably have 1 to 9 carbon atoms.

[0073] R 311 ~R 316 and R 321 ~R 326 The alkyl group having 1 to 22 carbon atoms is preferably a methyl group or an ethyl group.

[0074] R 311 ~R 316 and R 321 ~R 326 The alkoxy group having 1 to 22 carbon atoms is preferably a methoxy group, an ethoxy group, or an oleyloxy group.

[0075] Specific examples of aluminum chelate compounds include aluminum tris(acetylacetonate), aluminum tris(ethylacetoacetate), aluminum monoacetylacetonate bis(ethylacetoacetate), aluminum monoacetylacetonate bisoleylacetoacetate, ethylacetoacetate aluminum diisopropylate, and alkylacetoacetate aluminum diisopropylate.

[0076] The antibacterial agent used in the present invention is preferably a water-insoluble antibacterial agent. When the antibacterial agent is water-insoluble, it has excellent durability of antibacterial activity even when exposed to water such as rain. In this application, "water-insoluble" means that the amount of water required to dissolve 1 g of the antibacterial agent at 20°C is 10 ml or more.

[0077] The antibacterial agents, ie, a metal complex of a heteroatom-containing ligand and a metal ion and a metal complex of a heteroatom-containing ligand and a fatty acid metal salt, can be produced by a known method, for example, by reacting a metal or a fatty acid metal salt with a heteroatom-containing ligand. Alternatively, commercially available metal complexes may be used.

[0078] (organic solvent) The organic solvent used in the coating agent for paper substrates or plastic substrates of the present invention is not particularly limited, and examples include aromatic hydrocarbon organic solvents such as toluene, xylene, Solvesso #100, Solvesso #150, etc.; aliphatic hydrocarbon organic solvents such as hexane, methylcyclohexane, heptane, octane, decane, etc.; and various ester organic solvents such as methyl acetate, ethyl acetate, isopropyl acetate, normal propyl acetate, butyl acetate, amyl acetate, ethyl formate, butyl propionate, etc. Examples of water-miscible organic solvents include alcohols such as methanol, ethanol, propanol, butanol, and isopropyl alcohol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and glycol ethers such as ethylene glycol (mono- and di-)methyl ether, ethylene glycol (mono- and di-)ethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono- and di-)methyl ether, diethylene glycol (mono- and di-)ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono- and di-)methyl ether, propylene glycol (mono- and di-)methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol (mono- and di-)methyl ether. These can be used alone or in combination of two or more.

[0079] From the viewpoints of both work hygiene during printing and the harmfulness of packaging materials, it is more preferable to use ethyl acetate, propyl acetate, isopropanol, normal propanol, etc., and not to use aromatic solvents such as toluene or ketone solvents such as methyl ethyl ketone.

[0080] Among these, a mixture of isopropyl alcohol, ethyl acetate, and methoxypropanol is more preferable from the viewpoint of solubility in polyurethane resin and soluble nitrocellulose. Also, glycol ethers can be added in an amount of less than 10% by mass of the total coating agent to adjust the dryness. The coating agent for paper substrates or plastic substrates of the present invention may also contain waxes, chelating crosslinking agents, extender pigments, leveling agents, defoamers, plasticizers, infrared absorbers, ultraviolet absorbers, fragrances, flame retardants, and the like, for the purpose of imparting the coating agent with desired basic physical properties.

[0081] (Method of manufacturing a coating agent for paper substrates or plastic substrates) The coating agent for paper substrates or plastic substrates of the present invention can be produced by dissolving and / or dispersing the binder resin (A), the antibacterial agent (B), etc. in an organic solvent. As a dispersing machine, a commonly used one, such as a roller mill, a ball mill, a pebble mill, an attritor, or a sand mill, can be used.

[0082] The coating agent for paper substrates or plastic substrates of the present invention can be applied to substrates such as plastic materials, molded products, film substrates, and packaging materials by a common coating method, specifically, gravure roll coating (gravure coater), flexo roll coating (flexo coater), reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dip coating, brush coating, etc. Among these, from an industrial viewpoint, it is preferable to use gravure roll coating (gravure coater) and flexo roll coating (flexo coater).

[0083] Alternatively, a coating layer may be provided on a substrate by impregnating the substrate with the overcoating agent of the present invention. When the coating agent of the present invention is applied using a gravure coater, the viscosity thereof may be 12 to 30 seconds, more preferably 15 to 20 seconds, at 25° C. using a Zahn Cup #3 manufactured by Rigo Co., Ltd. When the coating agent of the present invention is applied using a flexo coater, the viscosity may be 7 to 40 seconds, more preferably 10 to 20 seconds, at 25°C using a Zahn Cup #4 manufactured by Rigo Co., Ltd.

[0084] The thickness of the coating layer of the present invention can be adjusted appropriately depending on the application and the material of the substrate, but is preferably in the range of 0.1 μm to 5 μm, more preferably 0.3 μm to 3 μm, and even more preferably 0.5 to 2 μm.

[0085] Since the coating agent for paper substrates or plastic substrates of the present invention has excellent dispersibility, the coating layer formed using the coating agent is likely to have a structure in which part of the antibacterial agent (B) is exposed, allowing the coating layer of the present invention to maximize its antibacterial effect.

[0086] (Coating agent for paper substrate or plastic substrate of the present invention) The substrate used in the present invention is a paper substrate or a plastic substrate.

[0087] (Paper base material) The paper base material is produced using natural fibers for papermaking, such as wood pulp, on a known papermaking machine, but the papermaking conditions are not particularly specified. Examples of natural fibers for papermaking include wood pulps such as softwood pulp and hardwood pulp, non-wood pulps such as Manila hemp pulp, sisal hemp pulp, and flax pulp, and pulps obtained by chemically modifying these pulps. Pulp types that can be used include chemical pulps produced by sulfate cooking, acidic, neutral, or alkaline sulfite cooking, and soda cooking, as well as ground pulp, chemi-ground pulp, and thermomechanical pulp. Also, various commercially available high-quality papers, coated papers, lined papers, impregnated papers, cardboards, paperboards, etc. can be used.

[0088] (Plastic substrate) The plastic substrate may be any substrate used for plastic materials, molded products, film substrates, packaging materials, etc. However, when using gravure roll coating (gravure coater) or flexo roll coating (flexo coater), film substrates that are commonly used in the gravure and flexo printing fields can be used as they are. Specific examples include films and laminates made of polyamide resins such as nylon 6, nylon 66, and nylon 46; polyester resins such as polyethylene terephthalate (hereinafter sometimes referred to as PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate; biodegradable resins such as polyhydroxycarboxylic acids such as polylactic acid, aliphatic polyester resins such as poly(ethylene succinate) and poly(butylene succinate); and thermoplastic resins such as polyolefin resins such as polypropylene and polyethylene, polyimide resins, polyarylate resins, and mixtures thereof. Among these, films made of polyethylene terephthalate (PET), polyester, polyamide, polyethylene, and polypropylene are preferred. These substrate films are made from either petroleum-derived or plant-derived raw materials, but either is acceptable in the present invention. These substrate films may be unstretched or stretched, and their manufacturing method is not limited. The thickness of the substrate film is also not particularly limited, but is generally within the range of 1 to 500 μm. The substrate film is preferably subjected to a corona discharge treatment, and may be vapor-deposited with aluminum, silica, alumina, or the like.

[0089] The substrate may also be a laminate (sometimes referred to as a laminate film) having a laminated structure in which the above-mentioned paper substrate or film substrate is laminated by dry lamination, solventless lamination, or extrusion lamination. The laminate may also include a metal foil, a metal vapor deposition film layer, an inorganic vapor deposition film layer, an oxygen absorbing layer, an anchor coat layer, a printed layer, a varnish layer, or the like. While there are many types of such laminates depending on the application, the configuration most commonly used today for food packaging and household goods is as follows: (F) represents the paper substrate or film substrate, (P) represents the printed or varnish layer, (M) represents the metal or inorganic layer of the metal foil or vapor deposition film layer, (AD) represents the adhesive layer, and (AD2) represents the hot-melt adhesive, heat seal agent, or cold seal agent. Specific embodiments of the laminate film can have the following configurations, but are not limited to these.

[0090] (F) / (P) / (F) (F) / (P) / (AD) / (F), (F) / (P) / (AD) / (F) / (AD) / (F), (F) / (P) / (AD) / (M) / (AD) / (F), (F) / (P) / (AD) / (M), (F) / (P) / (AD) / (F) / (AD) / (M) / (AD) / (F), (F) / (P) / (AD) / (M) / (AD) / (F) / (AD) / (F), (M) / (P) / (AD) / (M), (M) / (P) / (AD) / (F) / (AD) / (M), (P) / (F) (P) / (F) / (P) (P) / (F) / (AD) / (F), (P) / (F) / (AD) / (F) / (AD) / (F) (F) / (P) / (F) / (AD2) (F) / (P) / (AD2) (F) / (P) / (AD) / (M) / (AD2)

[0091] The single-layer paper substrate or film substrate, or laminate having a laminate structure, is variously expressed, depending on the industry, method of use, etc., as functional film, flexible packaging film, shrink film, film for packaging daily necessities, film for packaging pharmaceuticals, film for packaging food, cartons, posters, flyers, CD jackets, direct mail, pamphlets, fine paper, coated paper, art paper, imitation paper, tissue paper, cardboard, and various synthetic papers used for packaging of cosmetics, beverages, pharmaceuticals, toys, equipment, etc., but the coating agent for paper substrates or plastic substrates of the present invention can be used without any particular limitation. In this case, it is preferable that the coating agent for paper substrates or plastic substrates of the present invention is coated on the surface that will become the outermost layer when these are used to make containers or packaging materials.

[0092] As mentioned above, many laminates having a laminate structure have a printed layer formed on a paper substrate or a film substrate. However, the coating agent for paper substrates or plastic substrates of the present invention can also be preferably coated onto a substrate having such a printed ink layer.

[0093] There are no particular limitations on the printing ink used in the printing ink layer, and it is possible to coat the printing layer with offset lithographic ink, gravure printing ink, flexographic printing ink, inkjet printing ink, etc. In particular, when gravure roll coating (gravure coater) or flexographic roll coating (flexo coater) is used as the coating method, it is industrially preferable to combine it with gravure printing ink or flexographic printing ink, as this allows for in-line printing. Gravure printing ink and flexographic printing ink (hereinafter referred to as liquid printing ink) are formed from printing inks that consist of binder resins, pigments, solvents, and, if necessary, additives.

[0094] (liquid printing ink) Liquid printing inks used for gravure printing and flexographic printing are broadly divided into organic solvent-based liquid printing inks, which use organic solvents as the main solvent, and water-based liquid printing inks, which use water as the main solvent.

[0095] (organic solvent-based liquid printing ink) Organic solvent-based liquid printing inks are prepared by dispersing a mixture containing the modified pigment used in the present invention, as well as the binder resin, organic solvent medium, dispersant, antifoaming agent, etc., described below, in a disperser to obtain a pigment dispersion. To the resulting pigment dispersion, a resin, an aqueous medium, and, if necessary, additives such as a leveling agent, are added, followed by stirring and mixing. Dispersers commonly used in the production of gravure and flexographic printing inks, such as a bead mill, Eiger mill, sand mill, gamma mill, or attritor, are used for production.

[0096] The viscosity of organic solvent-based liquid printing inks, whether used as gravure inks or flexographic inks, is preferably in the range of 10 mPa·s or more to prevent pigment sedimentation and ensure adequate dispersion, and 1000 mPa·s or less to ensure efficient operation during ink production and printing. The above viscosity was measured at 25°C using a Tokimec B-type viscometer.

[0097] The viscosity of the ink can be adjusted by appropriately selecting the types and amounts of raw materials used, binder resins, pigments, organic solvents, etc. The viscosity of the ink can also be adjusted by adjusting the particle size and particle size distribution of the pigments in the ink.

[0098] (Creating printed materials) Organic solvent-based liquid printing inks have excellent adhesion to various substrates and can be used for printing on paper, synthetic paper, thermoplastic resin films, plastic products, steel plates, etc., and are useful as inks for gravure printing using gravure printing plates made by electronic engraving or the like, or for flexographic printing using flexographic printing plates made by resin or the like.

[0099] The film thickness of the printing ink formed by gravure printing or flexographic printing using the organic solvent-based liquid printing ink is, for example, 10 μm or less, and preferably 5 μm or less.

[0100] (binder resin) Binder resins for organic solvent-based liquid printing inks are not particularly limited, and include commonly used resins for general liquid printing inks, such as polyurethane resins, acrylic resins, vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-acrylic copolymer resins, chlorinated polypropylene resins, cellulose resins, polyamide resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, styrene resins, dammar resins, styrene-maleic acid copolymer resins, polyester resins, alkyd resins, polyvinyl chloride resins, rosin resins, rosin-modified maleic acid resins, terpene resins, phenol-modified terpene resins, ketone resins, cyclized rubber, chlorinated rubber, butyral, polyacetal resins, petroleum resins, and modified resins thereof. These resins can be used alone or in combination.

[0101] Among the above, preferred is a binder resin containing at least one selected from the group consisting of polyurethane resins, cellulose resins, polyamide resins, vinyl chloride-vinyl acetate copolymer resins, vinyl chloride-acrylic copolymer resins, ethylene-vinyl acetate copolymer resins, vinyl acetate resins, acrylic resins, styrene resins, styrene-maleic acid copolymer resins, dammar resins, rosin resins, rosin-modified maleic acid resins, ketone resins, and cyclized rubbers. The content of the binder resin is in the range of 1 to 50 mass % in terms of the solid content of the organic solvent-based liquid printing ink, and more preferably 2 to 40 mass %.

[0102] (organic solvent) The organic solvent for organic solvent-based liquid printing ink is not particularly limited, and examples thereof include aromatic hydrocarbon organic solvents such as toluene, xylene, Solvesso #100, Solvesso #150, etc.; aliphatic hydrocarbon organic solvents such as hexane, methylcyclohexane, heptane, octane, decane, etc.; and various ester organic solvents such as methyl acetate, ethyl acetate, isopropyl acetate, normal propyl acetate, butyl acetate, amyl acetate, ethyl formate, butyl propionate, etc. Examples of water-miscible organic solvents include alcohols such as methanol, ethanol, propanol, butanol, and isopropyl alcohol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, and glycol ethers such as ethylene glycol (mono- and di-)methyl ether, ethylene glycol (mono- and di-)ethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono- and di-)methyl ether, diethylene glycol (mono- and di-)ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono- and di-)methyl ether, propylene glycol (mono- and di-)methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol (mono- and di-)methyl ether. These can be used alone or in combination of two or more.

[0103] Organic solvent-based liquid printing inks may further contain waxes, chelating crosslinking agents, extender pigments, leveling agents, antifoaming agents, plasticizers, infrared absorbers, ultraviolet absorbers, fragrances, flame retardants, and the like, as required.

[0104] (coloring agent) The organic solvent-based liquid printing ink uses the above-mentioned modified pigment as a colorant, but may also use in combination with other organic pigments and / or inorganic pigments that are used in general inks, paints, recording agents, etc. Examples of organic pigments include soluble azo pigments, insoluble azo pigments, azo pigments, phthalocyanine pigments, halogenated phthalocyanine pigments, anthraquinone pigments, anthanthrone pigments, dianthraquinonyl pigments, anthrapyrimidine pigments, perylene pigments, perinone pigments, quinacridone pigments, thioindigo pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, azomethine azo pigments, flavanthrone pigments, diketopyrrolopyrrole pigments, isoindoline pigments, indanthrone pigments, and carbon black pigments. Other examples include carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, cromophtal yellow, cromophtal red, phthalocyanine blue, phthalocyanine green, dioxazine violet, quinacridone magenta, quinacridone red, indanthrone blue, pyrimidine yellow, thioindigo bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, daylight fluorescent pigments, etc. In addition, both non-acid-treated pigments and acid-treated pigments can be used.

[0105] Examples of inorganic pigments include white inorganic pigments such as titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, lithopone, antimony white, and gypsum. Among inorganic pigments, titanium oxide is particularly preferred. Titanium oxide exhibits a white color and is preferred in terms of coloring power, hiding power, chemical resistance, and weather resistance. From the viewpoint of printing performance, titanium oxide that has been treated with silica and / or alumina is preferred. Examples of inorganic pigments other than white include aluminum particles, mica, bronze powder, chrome vermilion, yellow lead, cadmium yellow, cadmium red, ultramarine, Prussian blue, red iron oxide, yellow iron oxide, iron black, and zircon. Aluminum is in powder or paste form, but it is preferably used in paste form from the standpoints of handleability and safety, and whether leafing or non-leafing aluminum is used is selected appropriately from the standpoints of brightness and concentration. The average particle size of the pigment is preferably in the range of 10 to 200 nm, and more preferably about 50 to 150 nm. The pigment is preferably contained in an amount sufficient to ensure the concentration and coloring strength of the organic solvent-based liquid printing ink, i.e., 1 to 60% by mass of the total mass of the ink, or 10 to 90% by mass in terms of the solids mass ratio in the ink. These pigments can be used alone or in combination of two or more types.

[0106] (Water-based liquid printing ink) The aqueous liquid printing ink is prepared by dispersing a mixture containing the modified pigment used in the present invention, as well as the binder resin, aqueous medium, dispersant, antifoaming agent, etc., which will be described later, in a disperser to obtain a pigment dispersion. The resulting pigment dispersion is then mixed with a resin, aqueous medium, and, if necessary, additives such as a leveling agent, and stirred. The disperser used for the production of gravure and flexographic printing inks is a bead mill, Eiger mill, sand mill, gamma mill, attritor, or the like, which are commonly used. When the aqueous liquid printing ink is used as a flexographic ink, its viscosity should be 7 to 25 seconds at 25°C using a Zahn Cup #4 (manufactured by Rigo Co., Ltd.), preferably 10 to 20 seconds. The surface tension of the resulting flexographic ink at 25°C is preferably 25 to 50 mN / m, more preferably 33 to 43 mN / m. The lower the surface tension of the ink, the better the ink's wetting ability to substrates such as films. However, if the surface tension is below 25 mN / m, the ink tends to spread and connect adjacent dots in halftone dot areas, which can easily cause a stain on the printed surface known as dot bridging. On the other hand, if the surface tension is above 50 mN / m, the ink's wetting ability to substrates such as films decreases, which can easily cause cissing.

[0107] On the other hand, when using an aqueous liquid printing ink as a gravure ink, its viscosity should be 7 to 25 seconds at 25°C using a Zahn Cup #3 (manufactured by Rigo Co., Ltd.), preferably 10 to 20 seconds. Furthermore, the surface tension of the resulting gravure ink at 25°C is preferably 25 to 50 mN / m, similar to that of flexographic ink, and more preferably 33 to 43 mN / m. The lower the surface tension of the ink, the better the ink's wetting ability to substrates such as film. However, if the surface tension is below 25 mN / m, the ink tends to spread and connect adjacent dots in halftone dot areas, which can easily cause a stain on the printed surface known as dot bridging. On the other hand, if the surface tension exceeds 50 mN / m, the ink's wetting ability to substrates such as film decreases, which can easily cause cissing.

[0108] (Creating printed materials) The aqueous liquid printing ink has excellent adhesion to various substrates and can be used for printing on paper, synthetic paper, thermoplastic resin films, plastic products, steel plates, etc., and is useful as an ink for gravure printing using a gravure printing plate made by electronic engraving or the like, or for flexographic printing using a flexographic printing plate made by a resin plate or the like.

[0109] The thickness of the printing ink formed by gravure printing or flexographic printing using the aqueous liquid ink is, for example, 10 μm or less, and preferably 5 μm or less.

[0110] (binder resin) The binder resin for aqueous liquid printing inks is not particularly limited, and examples of the binder resin that can be used in general aqueous liquid printing inks include urethane resins, polyvinyl alcohols, polyvinylpyrrolidones, polyacrylic acid, acrylic acid-acrylonitrile copolymers, potassium acrylate-acrylonitrile copolymers, acrylic ester polymer emulsions, polyester-based urethane dispersions, acrylic copolymers such as vinyl acetate-acrylic ester copolymers and acrylic acid-alkyl acrylate copolymers; styrene-acrylic acid resins such as styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene-methacrylic acid-acrylic acid alkyl ester copolymers, styrene-α-methylstyrene-acrylic acid copolymers, and styrene-α-methylstyrene-acrylic acid-acrylic acid alkyl ester copolymers; styrene-maleic acid; styrene-maleic anhydride; vinylnaphthalene-acrylic acid copolymers; vinylnaphthalene-maleic acid copolymers; vinyl acetate-ethylene copolymers, vinyl acetate-fatty acid vinylethylene copolymers, vinyl acetate-maleic ester copolymers, vinyl acetate-crotonic acid copolymers, and vinyl acetate-acrylic acid copolymers; and salts thereof. These binder resins can be used alone or in combination of two or more.

[0111] Among these, it is preferable to use an acrylic resin or a urethane resin as the binder resin because they are readily available, and in particular, an acrylic ester polymer emulsion or a polyester urethane dispersion is preferred.

[0112] The binder resin preferably accounts for 5 to 50% by mass, calculated as the solid content of the aqueous liquid printing ink. If it is 5% by mass or more, the strength of the ink coating is not reduced, and substrate adhesion, water abrasion resistance, and other properties are maintained at a good level. Conversely, if it is 50% by mass or less, a reduction in coloring power can be suppressed, high viscosity can be avoided, and workability is not impaired. Of these, a content of 5 to 40% by mass is even more preferable, and a content of 5 to 20% by mass is most preferable.

[0113] (aqueous medium) Examples of aqueous media for aqueous liquid printing inks include water, water-miscible organic solvents, and mixtures thereof. Examples of water-miscible organic solvents include alcoholic solvents such as methanol, ethanol, n-propanol, and isopropanol; ketone solvents such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol, and propylene glycol; alkyl ethers of polyalkylene glycols; and lactam solvents such as N-methyl-2-pyrrolidone. In the present invention, water alone may be used, or a mixture of water and a water-miscible organic solvent may be used, or a water-miscible organic solvent alone may be used. Furthermore, from the standpoints of safety and environmental impact, water alone or a mixture of water and a water-miscible organic solvent is preferred as the aqueous medium, with water alone being particularly preferred.

[0114] The aqueous liquid printing ink may also contain the above-mentioned colorants, extender pigments, pigment dispersants, leveling agents, antifoaming agents, plasticizers, infrared absorbers, ultraviolet absorbers, fragrances, flame retardants, etc. Among these, fatty acid amides such as oleic acid amide, stearic acid amide, erucic acid amide, etc., which impart abrasion resistance, slipperiness, etc., silicone-based and non-silicone antifoaming agents which suppress foaming during printing, and various dispersants which improve pigment wetting, etc., are useful. [Example]

[0115] The present invention will be explained in more detail with reference to the following examples. Hereinafter, "parts" and "%" are all based on mass.

[0116] (Preparation of vinyl chloride-vinyl acetate copolymer resin solution) As a vinyl chloride-vinyl acetate copolymer resin, Solvin A manufactured by Nissin Chemical Industry Co., Ltd. was dissolved in the following ratio to prepare a vinyl chloride-vinyl acetate copolymer resin solution. Solvine A 25 parts 75 parts methyl ethyl ketone

[0117] (Preparation of Cellulose-Based Resin Solution) As a cellulose-based resin, CAB-381-01 manufactured by Eastman Chemical Co. was dissolved in the following proportions to prepare a cellulose-based resin solution. CAB-381-01 20 copies 80 parts ethyl acetate

[0118] (Preparation of binder resin solution (A-1) 40 parts of the obtained vinyl chloride-vinyl acetate copolymer resin solution and 20 parts of the cellulose-based resin solution were added to prepare a binder resin solution (A-1).

[0119] (Preparation of polyurethane resin solution U) A four-neck flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube was charged with 100 parts of a polyester polyol (hydroxyl value: 108 mg KOH / g) derived from neopentyl glycol and sebacic acid, and 32.3 parts of isophorone diisocyanate. The mixture was reacted at 90°C for 10 hours under a nitrogen stream to produce a urethane prepolymer with an isocyanate group content of 3.08% by weight. 71.2 parts of ethyl acetate was then added to the mixture to form a homogeneous urethane prepolymer solution. The urethane prepolymer solution was then added to a mixture of 8.47 parts of isophorone diamine, 0.46 parts of di-n-butylamine, 143 parts of ethyl acetate, and 115 parts of isopropyl alcohol, and the mixture was stirred at 45°C for 5 hours to produce polyurethane resin solution U. The resulting polyurethane resin solution U had a resin solids concentration of 29.9% by weight and a weight-average molecular weight of 54,000.

[0120] (Preparation of nitrocellulose solution N) To 37.5 parts of industrial nitrocellulose H1 / 2 (nitrocellulose, solids content 70%, viscosity at 25.0% solution concentration 9.0-14.9% according to JIS K-6703, product of Taihei Chemical Products Co., Ltd.), 62.5 parts of a mixture of isopropyl alcohol / ethyl acetate / normal propyl acetate / methylcyclohexane (weight ratio 25 / 25 / 13 / 10) was added and mixed thoroughly to prepare nitrocellulose solution N.

[0121] (Preparation of rosin resin solution R) 50 parts of rosin resin (trade name: NEOCITE F-896, manufactured by Konan Kasei Co., Ltd.) was dissolved in 50 parts of isopropyl alcohol to obtain a rosin resin solution R with a solid content of 50%.

[0122] 40 parts of the obtained polyurethane resin solution U, 25 parts of the nitrocellulose solution N, and 5 parts of the rosin resin solution R were mixed to prepare a binder resin solution (A-2).

[0123] (Antibacterial agent: Preparation of fatty acid metal salt (Nd)) 224.8 parts by mass of neodecanoic acid and 60.0 parts by mass of neodymium oxide were reacted at 130°C, and after dehydration under reduced pressure at 130°C, 306.9 parts by mass of cyclohexane was added to obtain 570.0 parts by mass of a neodymium neodecanoate solution (fatty acid metal salt (Nd)). The neodymium content in the obtained fatty acid metal salt (Nd) was 8.8% by mass.

[0124] <Examples 1 and 2, Comparative Examples 1 to 4: Examples of Coating Agents> (Example 1: Method for preparing coating agent) A total of 100 parts of the binder resin solution (A-1), 60 parts of ethyl acetate, 16 parts of Monocizer ATBC (a plasticizer for inks manufactured by DIC Corporation), 2.5 parts of LUWAX AF-31 (a polyethylene wax manufactured by BASF), 2 parts of an antibacterial agent (a fatty acid metal salt (Nd)), 0.2 parts of an amide-based anti-settling agent, and the remainder methyl ethyl ketone were mixed and stirred to prepare a coating agent (1).

[0125] (Film coating method) The viscosity of coating agent (1) was adjusted to 16 seconds using a Zahn cup #3 dilution solvent of methyl ethyl ketone / ethyl acetate = 1 / 1, and then 4 parts of the isocyanate "Takenate D-160N" (manufactured by Mitsui Chemicals, Inc.) was added as a curing agent. The mixture was coated onto a polyethylene terephthalate (PET) film (E5102 12 μm, manufactured by Toyobo Co., Ltd.) using a 175 lines / inch gravure printing plate, and the organic solvent was dried to produce the film of Example 1.

[0126] Example 2 A coating agent was prepared in the same manner as in Example 1, except that the binder resin solution (A-2) was used instead of the binder resin solution (A-1) in Example 1. The viscosity was then adjusted to 16 seconds using a Zahn cup #3 diluted solvent of methyl ethyl ketone / ethyl acetate / isopropyl alcohol = 2 / 2 / 1. The coating agent was then coated on the treated surface of a biaxially oriented polypropylene film (Futamura Chemical Co., Ltd., FOR, thickness 20 μm) that had been corona discharge treated on one side, to prepare a film of Example 2.

[0127] (Comparative Examples 1, 2 to 4: Preparation of Coating Agent and Film Fabrication) The coating agents and films were prepared in the same manner as in Example 1, except that in Comparative Example 1 no antibacterial agent was added, in Comparative Example 2 0.5 parts of Zeomic LJ-10N (average particle size 8μ, manufactured by Sinanen Zeomic Co., Ltd.) which is a silver-based inorganic antibacterial agent was used, in Comparative Examples 3 and 4 0.5 parts of Zeomic AJ-10N (average particle size 2μ, manufactured by Sinanen Zeomic Co., Ltd.) which is a silver-based inorganic antibacterial agent was used, and in Comparative Example 4 1 part of LUWAX AF-31 (polyethylene wax manufactured by BASF) was used.

[0128] (Evaluation method) The films of Examples 1 and 2 and Comparative Examples 1 to 4 prepared by the above methods were evaluated as follows.

[0129] [Transparency] The haze value of the coating film surface prepared on the film was measured using a haze meter NDH7000 manufactured by Nippon Denshoku Industries Co., Ltd., and the transparency was evaluated. The lower the haze value, the higher the transparency, and a haze value of less than 15 is within the practical range.

[0130] [Adhesion] After cellophane tape (manufactured by Nichiban Co., Ltd.) was applied to the surface of the coating film prepared on the film, the tape was quickly peeled off, and the state of the film surface was visually evaluated. (Evaluation criteria) ◯: The coating film did not peel off from the film at all. △: Less than 30% of the coating film area peeled off from the film. ×: 30% or more of the area of ​​the coating film peeled off from the film.

[0131] [Scratch resistance] The surface of the coating film prepared on the film was rubbed back and forth with a fingernail 20 times, and the state of removal of the coating agent was visually evaluated. (Evaluation criteria) ◯: The coating film did not peel off from the film at all. △: Less than 30% of the coating film area peeled off from the film. ×: 30% or more of the area of ​​the coating film peeled off from the film.

[0132] [Abrasion resistance] The coating surface of each film was rubbed with fine paper using a Gakushin-type abrasion resistance tester, and the degree of peeling of the coating layer was visually determined (100 times back and forth with a load of 200g). (Evaluation criteria) ◯: The coating film did not peel off from the film at all. △: Less than 30% of the coating film area peeled off from the film. ×: 30% or more of the area of ​​the coating film peeled off from the film.

[0133] (Antibacterial test) Tests were conducted in accordance with the JIS Z2801-2010 Test Method for Plastic Products, etc., "Antibacterial Products - Antibacterial Test Methods - Antibacterial Effect" (mainly "5. Test Methods") using films coated with the coating agents of the Examples and Comparative Examples as samples. The bacterial strains in the test solution were Escherichia coli (NBRC3972) and Staphylococcus aureus (NBRC12732). The bacterial solution (bacterial solution NB concentration 1 / 100NB) was dropped onto the antibacterial coating surface of the sample, and the film was placed over the sample to ensure the bacterial solution was in close contact. The sample was then incubated at 35±1°C and a relative humidity of 90% or higher for 24 hours. The bacterial solution was then washed out, and the viable bacteria count per 1 cm2 of sample was measured. When the obtained antibacterial activity value was 2.0 or more, it was defined as having an antibacterial effect, and this was used as the evaluation criterion. The antibacterial activity value is calculated using the following formula. Antibacterial activity value (R) = Ut - At Ut: logarithm of viable bacteria count after incubation of uncoated antibacterial coating sample At: logarithm of viable cell count after incubation of antimicrobial-added sample

[0134] The evaluation was conducted on the following three levels: Antibacterial activity value (R) of 3.0 or more: Antibacterial Antibacterial activity value (R) is 2.0 or more but less than 3.0: High possibility of antibacterial activity Antibacterial activity value (R) less than 2.0: no antibacterial activity

[0135] The composition of the coating agent and the physical properties of the film having the coating layer are shown in Tables 1 and 2.

[0136] [Table 1]

[0137] [Table 2]

[0138] As a result, it is shown that the coating agent of the present invention has antibacterial properties, transparency, adhesion, scratch resistance, and abrasion resistance. On the other hand, Comparative Examples 2 and 3, which contained an inorganic antibacterial agent, were inferior in abrasion resistance and scratch resistance, and also decreased in transparency. Comparative Example 4 used an inorganic antibacterial agent with a small particle size and increased the amount of wax, which resulted in improved abrasion resistance and scratch resistance, but poor transparency.

Claims

1. Contains a binder resin (A), an antibacterial agent (B), and an organic solvent, the binder resin (A) is a combination selected from the group consisting of a urethane resin / vinyl chloride resin, a urethane resin / cellulose resin, a polyamide resin / cellulose resin, an acrylic resin / cellulose resin, and a vinyl chloride resin / cellulose resin; the antibacterial agent (B) is a metal salt of neodecanoic acid, The metal of the metal salt is selected from bismuth, neodymium, magnesium, lanthanum, gadolinium and samarium. A coating agent for paper substrates or plastic substrates, characterized in that

2. The coating agent for paper substrates or plastic substrates according to claim 1, further comprising an isocyanate compound (E).

3. A paper substrate or a plastic substrate coated with the coating agent according to claim 1.

4. The paper substrate or plastic substrate according to claim 3, further comprising a printed ink layer.

5. A container or packaging material using the paper substrate or plastic substrate according to claim 3 or 4.

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