CN114341279B - Aqueous liquid printing ink, printed matter and laminate - Google Patents

Abstract

An aqueous liquid printing ink comprising a colorant, a binder resin and an aqueous medium, wherein the aqueous liquid printing ink satisfies (1) to (3). (1) The total amount of the aqueous liquid printing ink contains 10 mass% or less of an organic solvent. (2) The aqueous medium contains water and an organic solvent (A) having a solubility in water (100 ml at 25 ℃) of 1 to 30 (g/100 ml). (3) The ratio of the organic solvent (a) to the other organic solvents (B) was 10: 90-100: 0.

Description

Aqueous liquid printing ink, printed matter and laminate

Technical Field

The present invention relates to an aqueous liquid printing ink such as an aqueous gravure ink and an aqueous flexographic ink, and a laminate using the same.

Background

In recent years, there has been a demand for aqueous printing inks of aqueous type which use as little organic solvent as possible from the viewpoints of environmental problems, resource saving, labor safety, disaster prevention, and the like. The aqueous printing ink is widely used for permeable printing of wrapping paper, coated paper, corrugated paper, etc., and the use of the aqueous printing ink is also expanding in the field of gravure printing of impermeable plastic film substrates, mainly for wrapping material applications.

The aqueous printing ink is insufficient in drying property and printing adaptability to a film substrate as compared with a solvent type printing ink using an organic solvent as a main solvent. Since water has a low drying rate and a high surface tension, there is a tendency that the leveling property is poor for an impermeable substrate such as a plastic film. In addition, foaming of the ink during continuous contact of the printing plate with the ink at the time of printing is also problematic.

In order to adjust leveling properties of an aqueous printing ink to a substrate, a commercially available leveling agent (also referred to as a surface conditioner or the like) is generally used, and in order to adjust foaming, an antifoaming agent is used, but these agents remain in the coating film after the ink coating film, and thus, there are cases where physical properties of the ink coating film after printing are adversely affected. As an aqueous printing ink composition which is an aqueous ink and has good drying and leveling properties and good fine line reproducibility and dot reproducibility when printed on a plastic film, there is known an aqueous printing ink composition which contains an aqueous binder resin varnish and a pigment as main components, and further contains 0.01 to 5% by weight, based on the solid content, of a fluorine-containing acrylic copolymer resin obtained by copolymerizing a fluoroalkyl (meth) acrylate monomer with another polymerizable monomer (for example, see patent literature 1), but which also remains in the ink film, and thus may adversely affect the physical properties of the ink film after printing.

As an aqueous printing ink using a mixed solvent of water and alcohol, for example, an ink described in patent document 2 is known. However, the purpose of the ink of patent document 2 is to provide a printing ink using an alcohol solvent to water ratio of 50: 50-100: 0, and is excellent in drying property, printing stability and physical properties, and is capable of easily recovering a volatile solvent during printing and recycling the solvent contributing to environmental protection, and is completely different from the ink of the present invention for the purpose of suppressing foaming and improving leveling property to a substrate.

Patent document 1: japanese patent laid-open No. 10-158565

Patent document 2: WO2012/008339

Disclosure of Invention

Problems to be solved by the invention

The present invention addresses the problem of providing an aqueous liquid printing ink which has excellent leveling properties even when using a small amount of an organic solvent, does not foam the ink during printing, and has excellent physical properties of an ink coating film after printing, and a laminate using the aqueous liquid printing ink.

Means for solving the problems

The present inventors have found that the above problems are solved by an aqueous liquid printing ink comprising a colorant, a binder resin and an aqueous medium, wherein the aqueous medium comprises an organic solvent (a) having a solubility in water (in 100ml of water and at 25 ℃) of 1 to 30, and the ratio of water to the organic solvent (a) is 90: 10-100: 0, and the organic solvent (a) is contained in an amount of 10 mass% or less based on the total amount of the aqueous liquid printing ink.

That is, the present invention relates to an aqueous liquid printing ink which contains a colorant, a binder resin and an aqueous medium, and satisfies (1) to (3).

(1) The total amount of the aqueous liquid printing ink contains 10 mass% or less of an organic solvent.

(2) The aqueous medium contains water and an organic solvent (A) having a solubility in water (100 ml at 25 ℃) of 1 to 30 (g/100 ml).

(3) The ratio of the organic solvent (a) to the other organic solvents (B) was 10: 90-100: 0.

The present invention also relates to an aqueous liquid printing ink, wherein the organic solvent (a) is 1-butanol and/or isobutanol.

The present invention also relates to an aqueous liquid printing ink containing an acrylic resin or a urethane resin as the binder resin.

Furthermore, the present invention relates to an aqueous liquid printing ink, which is applied to flexographic printing or gravure printing.

The present invention also relates to a printed matter obtained by printing the aqueous liquid printing ink on a substrate.

The present invention also relates to a laminate comprising 1 or more printed layers on a plastic film, wherein at least 1 of the printed layers is a printed layer of the aqueous liquid printing ink.

Effects of the invention

The aqueous liquid printing ink of the present invention is excellent in leveling property even when using a small amount of an organic solvent, free from bubbling of ink during printing, and excellent in physical properties of an ink film after printing.

Detailed Description

The present invention will be described in detail. The term "ink" used in the following description is intended to mean "aqueous liquid printing ink". In addition, "parts" all represent "parts by mass" and "%" all represent "% by mass".

(aqueous Medium)

The aqueous medium used in the aqueous liquid printing ink of the present invention is an aqueous medium containing water as a main component, and is characterized in that the aqueous liquid printing ink satisfies the following (1) to (3).

(1) The total amount of the aqueous liquid printing ink contains 10 mass% or less of an organic solvent.

(2) The aqueous medium contains water and an organic solvent (A) having a solubility in water (100 ml at 25 ℃) of 1 to 30 (g/100 ml).

(3) The ratio of the organic solvent (a) to the other organic solvents (B) was 10: 90-100: 0.

(1) The organic solvent (a) is preferably contained in an amount of 10 mass% or less based on the total amount of the aqueous liquid printing ink. Among them, from the viewpoint of solubility in water, the solubility is preferably 8 mass% or less, most preferably 6 mass% or less, and the lower limit is preferably 1 mass% or more, more preferably 3 mass% or more.

(2) The aqueous medium preferably contains water and an organic solvent (A) having a solubility in water (100 ml 25 ℃) of 1 to 30 (g/100 ml).

In the present invention, the solubility in water is expressed in g (grams) dissolved in 100ml of water at 25 ℃. Examples of the organic solvent (A) having a solubility of 1 to 30 in water at 25℃include 1-butanol (solubility: 6.57 g.multidot.100 mL), isobutanol (solubility: 8.5 g.multidot.100 mL), 1-pentanol (2.2 g/100 mL), 2-methyl-2-pentanol (3.24 g/100 mL), 3-methyl-3-pentanol (4.5 g/100 mL), methyl ethyl ketone (22.3 g/100 mL) and the like. Among them, 1-butanol (solubility: 6.57g/100 ml) and isobutanol (solubility: 8.5g/100 ml) are preferable.

These organic solvents (a) may be used in combination of 2 or more kinds as needed.

(3) The ratio of the organic solvent (a) to the other organic solvents (B) is preferably 10: 90-100: 0. Among them, 30: 70-100: 0, most preferably 50: 50-100: 0.

The aqueous liquid printing ink of the present invention, which is excellent in leveling property, free from bubbling of ink during printing, and excellent in physical properties of an ink coating film after printing, can be obtained by satisfying the above aqueous media (1) to (3), but it is not yet confirmed that this is inferred as follows.

That is, in the present invention, as defined in the above (2), by using an organic solvent having a slightly low solubility in water (a liquid having a solubility in water in the range of 1 to 30 is generally considered to have a low solubility) in a ratio of 1 or less with respect to water, it is possible to achieve balance of surface tension and to be effective in defoaming.

In the present invention, the number of the components, among others,

(1) The total amount of the aqueous liquid printing ink contains 8 wt% or less of an organic solvent (A),

(2) Wherein the organic solvent (A) is 1-butanol and/or isobutanol,

(3) More preferably, the ratio of the organic solvent (a) to the other organic solvent (B) is 30: 70-100: a combination of proportions of 0,

in addition, in the case of the optical fiber,

(1) The total amount of the aqueous liquid printing ink contains 6 wt% or less of an organic solvent (A),

(2) Wherein the organic solvent (A) is 1-butanol and/or isobutanol,

(3) Most preferably, the ratio of the organic solvent (a) to the other organic solvents (B) is 50: 50-100: 0.

In the aqueous medium used in the present invention, the other organic solvent (B) is a water-miscible organic solvent having a solubility in water (100 ml at 25 ℃) other than 1 to 30 (g/100 ml), and may be used within a range not impairing the effect of the present invention.

Examples of the organic solvent which is completely miscible with water and has a solubility of 30 (g/100 ml) or more in water (100 ml 25 ℃) include monofunctional alcohols such as methanol, ethanol, n-propanol (hereinafter also referred to as NPA) and isopropanol (hereinafter also referred to as IPA), various diols, and polyhydric alcohols such as glycerin.

Examples of the diols include ethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, 1, 4-butanediol, 1, 6-hexanediol, 1, 8-octanediol, 1, 9-nonanediol, 1, 10-decanediol, 1, 12-dodecanediol, propylene glycol, 1, 2-butanediol, 3-methyl-1, 3-butanediol, 1, 2-pentanediol, 2-methyl-1, 3-propanediol, 1, 2-hexanediol, dipropylene glycol, diethylene glycol, and the like.

Examples of the aromatic diol which is an adduct of bisphenol A and an alkylene oxide having 2 or 3 carbon atoms (average molar number of addition of 1 to 16) of bisphenol A include polyoxypropylene-2, 2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2, 2-bis (4-hydroxyphenyl) propane.

Further, alicyclic diols such as cyclohexanediol and hydrogenated bisphenol A are mentioned.

Further, ethers include ethylene glycol monomethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol monoisobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monoisobutyl ether, propylene glycol monomethyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and ethyl carbitol.

Further, lactones such as gamma-butyrolactone and the like can be mentioned.

Among them, methanol, ethanol, n-propanol (hereinafter, also referred to as NPA), isopropanol (hereinafter, also referred to as IPA), propylene glycol monomethyl ether (1-methoxy 2-propanol) (also referred to as PGM), and ethylene glycol are preferable.

Further, as the solvent having a solubility of less than 1 (g/100 ml) in water (100 ml 25 ℃), for example, an aromatic solvent such as toluene, an acetate such as butyl acetate (excluding propyl acetate and ethyl acetate having a solubility of 1g/100ml or more), and a hydrocarbon solvent containing an alkane may be used as long as it is miscible with the organic solvent a in the aqueous ink.

Among them, toluene, butyl acetate, methylcyclohexane are preferable.

The other organic solvents (B) may be used in combination of 2 or more kinds as needed.

(colorant)

The aqueous liquid printing ink of the invention contains a colorant. Examples of the colorant include dyes, inorganic pigments, and organic pigments used in usual inks, paints, and recording agents. Among them, pigments such as inorganic pigments and organic pigments are preferable.

Examples of the organic pigment include pigments such as soluble azo pigments, insoluble azo pigments, phthalocyanine pigments, halogenated phthalocyanine pigments, anthraquinone pigments, anthroquinone pigments, dianthrone pigments, anthrapyrimidine pigments, perylene pigments, perinone pigments, quinacridone pigments, thioindigo pigments, dioxazine pigments, isoindolinone pigments, quinophthalone pigments, azomethine azo pigments, flavanones pigments, diketopyrrolopyrrole pigments, isoindoline pigments, indanthrone pigments, and carbon black pigments. Examples of the dye include carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, solid transparent (Cromophtal) yellow, solid transparent red, phthalocyanine blue, phthalocyanine green, dioxazine violet, quinacridone magenta, quinacridone red, indanthrene blue, pyrimidine yellow, thioindigo red, thioindigo magenta, perylene red, perylene orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, and fluorescent pigment. In addition, both non-acid treated pigments and acid treated pigments may be used. Specific examples of the organic pigment which is preferable as the organic pigment are given below.

Examples of the black pigment include c.i. pigment black 1, c.i. pigment black 6, c.i. pigment black 7, c.i. pigment black 9, c.i. pigment black 20, and the like.

Examples of the blue pigment include c.i. pigment blue 15 and c.i. pigment blue 15: 1. c.i. pigment blue 15: 2. c.i. pigment blue 15: 3. c.i. pigment blue 15: 4. c.i. pigment blue 15: 5. c.i. pigment blue 15: 6. c.i. pigment blue 16, c.i. pigment blue 17: 1. c.i. pigment blue 22, c.i. pigment blue 24: 1. c.i. pigment blue 25, c.i. pigment blue 26, c.i. pigment blue 60, c.i. pigment blue 61, c.i. pigment blue 62, c.i. pigment blue 63, c.i. pigment blue 64, c.i. pigment blue 75, c.i. pigment blue 79, c.i. pigment blue 80, and the like.

Examples of the green pigment include c.i. pigment green 1, c.i. pigment green 4, c.i. pigment green 7, c.i. pigment green 8, c.i. pigment green 10, and c.i. pigment green 36.

Examples of the red pigment include c.i. pigment red 1, c.i. pigment red 2, c.i. pigment red 3, c.i. pigment red 4, c.i. pigment red 5, c.i. pigment red 6, c.i. pigment red 7, c.i. pigment red 8, c.i. pigment red 9, c.i. pigment red 10, c.i. pigment red 11, c.i. pigment red 12, c.i. pigment red 15, c.i. pigment red 16, c.i. pigment red 17, c.i. pigment red 18, c.i. pigment red 19, c.i. pigment red 20, c.i. pigment red 21, c.i. pigment red 22, c.i. pigment red 23, c.i. pigment red 31, c.i. pigment red 32, c.i. pigment red 38, c.i. pigment red 41, c.i. pigment red 43, c.i. pigment red 46, c.i. pigment red 48. 1. C.i. pigment red 48: 2. c.i. pigment red 48: 3. c.i. pigment red 48: 4. c.i. pigment red 48: 5. c.i. pigment red 48: 6. c.i. pigment red 49, c.i. pigment red 49: 1. c.i. pigment red 49: 2. c.i. pigment red 49: 3. c.i. pigment red 52, c.i. pigment red 52: 1. c.i. pigment red 52: 2. c.i. pigment red 53, c.i. pigment red 53: 1. c.i. pigment red 53: 2. c.i. pigment red 53: 3. c.i. pigment red 54, c.i. pigment red 57: 1. c.i. pigment red 58, c.i. pigment red 58: 1. c.i. pigment red 58: 2. c.i. pigment red 58: 3. c.i. pigment red 58: 4. c.i. pigment red 60: 1. c.i. pigment red 63, c.i. pigment red 63: 1. c.i. pigment red 63: 2. c.i. pigment red 63: 3. c.i. pigment red 64: 1. c.i. pigment red 68, c.i. pigment red 81: 1. c.i. pigment red 83, c.i. pigment red 88, c.i. pigment red 89, c.i. pigment red 95, c.i. pigment red 112, c.i. pigment red 114, c.i. pigment red 119, c.i. pigment red 122, c.i. pigment red 123, c.i. pigment red 136, c.i. pigment red 144, c.i. pigment red 146, c.i. pigment red 147, c.i. pigment red 149, c.i. pigment red 150, c.i. pigment red 164, c.i. pigment red 166, c.i. pigment red 168, c.i. pigment red 169, c.i. pigment red 170, c.i. pigment red 171, c.i. pigment red c.i. pigment red 172, c.i. pigment red 175, c.i. pigment red 176, c.i. pigment red 177, c.i. pigment red 178, c.i. pigment red 179, c.i. pigment red 180, c.i. pigment red 181, c.i. pigment red 182, c.i. pigment red 183, c.i. pigment red 184, c.i. pigment red 185, c.i. pigment red 187, c.i. pigment red 188, c.i. pigment red 190, c.i. pigment red 192, c.i. pigment red 193, c.i. pigment red 194, c.i. pigment red 200, c.i. pigment red 202, c.i. pigment red 206 c.i. pigment red 207, c.i. pigment red 208, c.i. pigment red 209, c.i. pigment red 210, c.i. pigment red 211, c.i. pigment red 213, c.i. pigment red 214, c.i. pigment red 216, c.i. pigment red 215, c.i. pigment red 216, c.i. pigment red 220, c.i. pigment red 221, c.i. pigment red 223, c.i. pigment red 224, c.i. pigment red 226, c.i. pigment red 237, c.i. pigment red 238, c.i. pigment red 239, c.i. pigment red 240, c.i. pigment red 242, c.i. pigment red 245 c.i. pigment red 247, c.i. pigment red 248, c.i. pigment red 251, c.i. pigment red 253, c.i. pigment red 254, c.i. pigment red 255, c.i. pigment red 256, c.i. pigment red 257, c.i. pigment red 258, c.i. pigment red 260, c.i. pigment red 262, c.i. pigment red 263, c.i. pigment red 264, c.i. pigment red 266, c.i. pigment red 268, c.i. pigment red 269, c.i. pigment red 270, c.i. pigment red 271, c.i. pigment red 272, c.i. pigment red 279, and the like.

Examples of violet pigments include c.i. pigment violet 1, c.i. pigment violet 2, c.i. pigment violet 3, and c.i. pigment violet 3: 1. c.i. pigment violet 3: 3. c.i. pigment violet 5: 1. c.i. pigment violet 13, c.i. pigment violet 19 (gamma, beta), c.i. pigment violet 23, c.i. pigment violet 25, c.i. pigment violet 27, c.i. pigment violet 29, c.i. pigment violet 31, c.i. pigment violet 32, c.i. pigment violet 36, c.i. pigment violet 37, c.i. pigment violet 38, c.i. pigment violet 42, c.i. pigment violet 50, and the like.

Examples of the yellow pigment include c.i. pigment yellow 1, c.i. pigment yellow 3, c.i. pigment yellow 12, c.i. pigment yellow 13, c.i. pigment yellow 14, pigment yellow 17, c.i. pigment yellow 24, c.i. pigment yellow 42, c.i. pigment yellow 55, c.i. pigment yellow 62, c.i. pigment yellow 65, c.i. pigment yellow 74, c.i. pigment yellow 83, c.i. pigment yellow 86, c.i. pigment yellow 93, c.i. pigment yellow 94, c.i. pigment yellow 95, c.i. pigment yellow 109, c.i. pigment yellow 110, c.i. pigment yellow 117, c.i. pigment yellow 120, pigment yellow 125, c.i. pigment yellow 128, c.i. pigment yellow 129, c.i. pigment yellow 138, c.i. pigment yellow 139, c.i. pigment yellow 147, c.i. pigment yellow 148, c.i. pigment yellow 150, c.i. pigment yellow 166, c.i. pigment yellow 180, c.i. pigment yellow 155, c.i. pigment yellow 180, c.i. pigment yellow 166, c.i. pigment yellow 213.

Examples of orange pigments include c.i. pigment orange 5, c.i. pigment orange 13, c.i. pigment orange 16, c.i. pigment orange 34, c.i. pigment orange 36, c.i. pigment orange 37, c.i. pigment orange 38, c.i. pigment orange 43, c.i. pigment orange 51, c.i. pigment orange 55, c.i. pigment orange 59, c.i. pigment orange 61, c.i. pigment orange 64, c.i. pigment orange 71, and c.i. pigment orange 74.

Examples of the brown pigment include c.i. pigment brown 23, c.i. pigment brown 25, and c.i. pigment brown 26.

Among them, preferred pigments are c.i. pigment black 7,

examples of the blue pigment include c.i. pigment blue 15 and c.i. pigment blue 15: 1. c.i. pigment blue 15: 2. c.i. pigment blue 15: 3. c.i. pigment blue 15: 4. c.i. pigment blue 15:6,

examples of the green pigment include c.i. pigment green 7,

as the red pigment, c.i. pigment red 57: 1. c.i. pigment red 48: 1. c.i. pigment red 48: 2. c.i. pigment red 48: 3. c.i. pigment red 146, c.i. pigment red 242, c.i. pigment red 185, c.i. pigment red 122, c.i. pigment red 178, c.i. pigment red 149, c.i. pigment red 144, c.i. pigment red 166,

examples of the violet pigment include c.i. pigment violet 23, c.i. pigment violet 37,

Examples of the yellow pigment include c.i. pigment yellow 83, c.i. pigment yellow 14, c.i. pigment yellow 180, c.i. pigment yellow 139,

examples of the orange pigment include c.i. pigment orange 38, c.i. pigment orange 13, c.i. pigment orange 34, and c.i. pigment orange 64, and at least one or two or more selected from these are preferably used.

Examples of the inorganic pigment include white inorganic pigments such as titanium oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, lithopone, antimony white, and gypsum. Among the inorganic pigments, titanium oxide is particularly preferably used. Titanium oxide is white, and is preferable in terms of coloring power, masking power, chemical resistance, and weather resistance, and is preferably treated with silica and/or alumina from the viewpoint of printing performance.

Examples of the inorganic pigment other than white include aluminum particles, mica (mica), bronze powder, chrome vermilion, chrome yellow, cadmium red, ultramarine blue, deep blue, red lead, iron oxide yellow, iron black, zirconium, and aluminum is powder or paste, and is preferably used in paste form from the viewpoint of handling properties and safety, and from the viewpoint of brightness and concentration, whether a floating agent or a non-floating agent is used is appropriately selected.

The average particle diameter of the pigment is preferably in the range of 10 to 200nm, more preferably about 50 to 150 nm.

The pigment is preferably contained in a proportion of 1 to 60% by weight, based on the total weight of the ink composition, and 10 to 90% by weight, based on the weight ratio of the solid content in the ink composition, in terms of a sufficient amount to ensure the concentration and tinting strength of the liquid printing ink. In addition, these pigments may be used singly or in combination of 2 or more.

(Binder resin)

The aqueous liquid printing ink of the invention contains a binder resin. The binder resin is not particularly limited, and acrylic copolymers such as urethane resins, polyvinyl alcohols, polyvinyl pyrrolidone, polyacrylic acid, acrylic acid-acrylonitrile copolymers, potassium acrylate-acrylonitrile copolymers, vinyl acetate-acrylic acid ester copolymers, and acrylic acid-alkyl acrylate copolymers used in usual aqueous liquid printing inks can be used; styrene-acrylic resins such as styrene-acrylic copolymers, styrene-methacrylic-alkyl acrylate copolymers, styrene- α -methylstyrene-acrylic copolymers, and styrene- α -methylstyrene-acrylic-alkyl acrylate copolymers; styrene-maleic acid; styrene-maleic anhydride; vinyl naphthalene-acrylic copolymers; vinyl naphthalene-maleic acid copolymers; vinyl acetate copolymers such as vinyl acetate-ethylene copolymers, vinyl acetate-fatty acid vinyl ethylene copolymers, vinyl acetate-maleic acid ester copolymers, vinyl acetate-crotonic acid copolymers, and vinyl acetate-acrylic acid copolymers, and salts thereof. These may be used in combination as appropriate according to desired physical properties.

Among them, the use of an acrylic resin or a urethane resin as the binder resin is preferable.

(acrylic resin)

The acrylic resin is not particularly limited, and examples thereof include homo-or copolymerization of (meth) acrylic acid esters and copolymers obtained by copolymerizing (meth) acrylic acid esters with copolymerizable vinyl monomers. In addition, for the purpose of imparting water dispersibility and water solubility, a copolymer having an acid value is preferable.

In the present invention, "(meth) acrylate" means either or both of acrylate and methacrylate, and "(meth) acrylic acid" means either or both of acrylic acid and methacrylic acid.

Examples of the (meth) acrylic acid ester and the vinyl monomer copolymerizable with the (meth) acrylic acid ester include alkyl (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, t-butyl (meth) acrylate, isopropyl (meth) acrylate, isobutyl (meth) acrylate, and the like; aromatic (meth) acrylates such as benzyl (meth) acrylate; hydroxy-containing monomers such as 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate; alkyl polyalkylene glycol mono (meth) acrylates such as methoxypolyethylene glycol mono (meth) acrylate and methoxypolypropylene glycol mono (meth) acrylate; fluorine-based (meth) acrylates such as perfluoroalkyl ethyl (meth) acrylate; aromatic vinyl compounds such as styrene, styrene derivatives (p-dimethylsilylstyrene, (p-vinylphenyl) methyl sulfide, p-hexynylstyrene, p-methoxystyrene, p-t-butyldimethylsilyloxy styrene, o-methylstyrene, p-t-butylstyrene, and α -methylstyrene), vinylnaphthalene, vinylanthracene, and 1, 1-diphenylethylene; (meth) acrylate compounds such as glycidyl (meth) acrylate, epoxy (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylene glycol tetra (meth) acrylate, 2-hydroxy-1, 3-diacryloyloxypropane, 2-bis [4- (acryloyloxymethoxy) phenyl ] propane, 2-bis [4- (acryloyloxyethoxy) phenyl ] propane, dicyclopentenyl (meth) acrylate tricyclodecyl (meth) acrylate, tris (acryloyloxyethyl) isocyanurate, and urethane (meth) acrylate; (meth) acrylic esters having an alkylamino group such as dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate and the like; vinyl pyridine compounds such as 2-vinyl pyridine, 4-vinyl pyridine and naphthylvinyl pyridine; conjugated dienes such as 1, 3-butadiene, 2-methyl-1, 3-butadiene, 2, 3-dimethyl-1, 3-butadiene, 1, 3-pentadiene, 1, 3-hexadiene, and 1, 3-cyclohexadiene. These monomers may be used in an amount of 1 or 2 or more.

In order to introduce 1 or more acid groups selected from the carboxylic acid groups in which the carboxyl groups and the carboxylic acid ester groups in which the carboxyl groups are neutralized with a basic compound, a (meth) acrylic monomer having a carboxyl group such as (meth) acrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, β - (meth) acryloyloxyethyl succinate, β - (meth) acryloyloxyethyl phthalate, or the like may be copolymerized to obtain a copolymer having an acid value.

In the case of introducing an acidic group, the amount of the monomer is preferably adjusted so that the acid value falls within a desired range, as will be described in detail later.

The copolymer can be produced, for example, by polymerizing various monomers in the presence of a polymerization initiator at a temperature range of 50 to 180 ℃, and more preferably at a temperature range of 80 to 150 ℃. Examples of the polymerization method include bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Examples of the polymerization system include random copolymers, block copolymers, and graft copolymers.

The copolymer used in the present invention may be of a core-shell type. In the core-shell resin of the present invention, the polymer (a 2) is dispersed in an aqueous medium by the polymer (a 1), and in general, the polymer (a 1) is present at the outermost part of the resin particles to form a shell part, and a part or all of the polymer (a 2) often forms a core part. Hereinafter, in the present invention, the resin forming the shell portion is referred to as a polymer (a 1), and the resin forming the core portion is referred to as a polymer (a 2).

[ Polymer (a 1) constituting the Shell portion ]

The core-shell resin used in the present invention is preferably composed of a polymer (a 1) constituting a shell portion, the polymer (a 1) containing an acrylic resin having 1 or more hydrophilic groups selected from a carboxyl group and a carboxylate group formed by neutralizing the carboxyl group. In this case, the acid value of the shell portion is preferably in the range of 40mgKOH/g or more and 250mgKOH/g or less, more preferably 120mgKOH/g or less.

The carboxyl group of the polymer (a 1) constituting the shell portion is preferably neutralized with an alkaline compound to form a carboxylate group.

As the basic compound that can be used for the neutralization, for example, ammonia, triethylamine, morpholine, monoethanolamine, diethylethanolamine, etc. can be used, and ammonia and triethylamine are preferably used in order to further improve the hot water resistance, corrosion resistance, and chemical resistance of the coating film.

The amount of the basic compound used is preferably in a range of [ basic compound/carboxyl group ] =0.2 to 2 (molar ratio) relative to the total amount of carboxyl groups in the polymer (a 1), in order to further improve the water dispersion stability of the obtained core-shell resin.

Among the above-mentioned monomers having a polymerizable unsaturated double bond, a monomer obtained by polymerizing a (meth) acrylic monomer containing a (meth) acrylic monomer having a carboxyl group is preferably used. In particular, as the polymer (a 1), a polymer obtained by polymerizing a combination of methyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylic acid is used in order to adjust the glass transition temperature (Tg 1) of the polymer (a 1) to a range of 20 to 100 ℃, and it is more preferable in terms of forming a coating film excellent in film forming property and excellent in hot water resistance, corrosion resistance, and chemical resistance.

[ Polymer (a 2) constituting the core ]

The polymer (a 2) constituting the core may be a copolymer of an acrylic monomer or the like similar to the acrylic resin.

In this case, the weight average molecular weight of the core is preferably in the range of 200000 ～ 3000000, more preferably 800000 or more. Tg is preferably in the range of-30℃to 30 ℃.

The polymer (a 2) constituting the core may be a copolymer of an acrylic monomer or the like similar to the acrylic resin, and is preferably produced using an aqueous medium. Specifically, the polymer can be produced by supplying the above-mentioned monomer, polymerization initiator, and the like to a reaction vessel containing an aqueous medium at once or sequentially, and polymerizing the monomers. In this case, the monomer, the aqueous medium, and the reactive surfactant or the like as needed may be mixed in advance to prepare a pre-emulsion, which is supplied to a reaction vessel containing the aqueous medium together with a polymerization initiator or the like to perform polymerization.

Examples of the polymerization initiator that can be used for producing the polymer (a 2) include radical polymerization initiators such as persulfates, organic peroxides, and hydrogen peroxide, and azo initiators such as 4,4 '-azobis (4-cyanovaleric acid) and 2,2' -azobis (2-amidinopropane) dihydrochloride. The radical polymerization initiator may be used as a redox polymerization initiator in combination with a reducing agent described later.

Examples of the persulfate include potassium persulfate, sodium persulfate, and ammonium persulfate. Examples of the organic peroxide include benzoyl peroxide, lauroyl peroxide, decanoyl peroxide, t-butylcumene peroxide, diisopropylbenzene peroxide, t-butyllaurate peroxide, t-butylbenzoate peroxide, cumene hydroperoxide, p-menthane hydroperoxide, and t-butylhydroperoxide.

Examples of the reducing agent include ascorbic acid and its salts, erythorbic acid and its salts (sodium salt, etc.), tartaric acid and its salts, citric acid and its salts, metal salts of formaldehydesulfoxylate, sodium thiosulfate, sodium bisulfate, ferric chloride, etc.

The amount of the polymerization initiator to be used is preferably small, and is preferably 0.01 to 0.5 mass% based on the total amount of the monomers used for producing the vinyl polymer (a 2), from the viewpoint of maintaining excellent corrosion resistance of the obtained coating film. In the case where the polymerization initiator and the reducing agent are used in combination, the total amount of these components is preferably within the above range.

In addition, in the production of the above-mentioned pre-emulsion, a reactive surfactant, an anionic surfactant, a nonionic surfactant, a cationic surfactant, a zwitterionic surfactant, or the like may be used.

The acid value of the copolymer is preferably 20mgKOH/g or more and 120mgKOH/g or less, more preferably 25 mgKOH/g or more. When the acid value is 20mgKOH/g or more, the friction resistance, water friction resistance and scratch resistance of the laminate can be improved when the curing agent is added.

The acid value here means the number of milligrams of potassium hydroxide required for neutralization of the acidic component contained in 1g of the resin.

The weight average molecular weight of the copolymer is preferably in the range of 5000 to 100000. If the weight average molecular weight is 5000 or more, the heat resistance of the resin film will not decrease, and the friction resistance and the water friction resistance of the laminate will tend to be maintained. If the thickness is 100000 or less, the substrate adhesion and scratch resistance of the laminate tend to be both achieved.

The glass transition temperature (Tg) of the copolymer is preferably in the range of 0℃to 55 ℃. If the Tg of the copolymer is 0 ℃ or less, the film strength can be maintained, and the water friction resistance of the laminate is not lowered, and if the Tg is 55 ℃ or less, the compatibility with other printed layers is not lowered, and the friction resistance, water friction resistance, and scratch resistance of the laminate tend to be well maintained.

The glass transition temperature (Tg 1) is a calculated glass transition temperature, and is a value calculated by the following method.

(formula 1) 1/Tg (K) = (W1/T1) + (W2/T2) +. Cndot. Wn/Tn

(formula 2) Tg (°c) =tg (K) -273

W1, W2 in formula 1 the term Wn represents the mass% of each monomer relative to the total mass of the monomers used in the production of the polymer, T1, T2 Tn represents the glass transition temperature (K) of the homopolymer of each monomer. The values of T1, T2, ··Tn were as described in Polymer Handbook (fourth edition, code J.Brandrup, E.H.Immergut, E.A.Grulke).

The glass transition temperature of the homopolymer of each monomer was not shown in Polymer Hand Book, but was measured by the method according to JIS K7121 using a differential scanning calorimeter "DSC Q-100" (manufactured by TA instruments Co., ltd.). Specifically, for the polymer from which the solvent was completely removed by vacuum suction, the change in heat was measured at a temperature rise rate of 20 ℃/min in the range of-100 ℃ to +200 ℃, and the point at which a straight line equidistant from the straight line extending from each base line in the longitudinal axis direction intersects with the curve of the stepwise change portion of the glass transition was regarded as the glass transition temperature.

(urethane resin)

Examples of the urethane resin include a polyol such as a polyether polyol, a polyester polyol, and a polycarbonate polyol, a polyol having a hydrophilic group such as an anionic group, a cationic group, a polyoxyethylene group, and a polyoxyethylene-polyoxypropylene group, and a urethane resin obtained by reacting a polyisocyanate. The weight average molecular weight of the urethane resin is not particularly limited, and is usually 5000 to 200000, more preferably 20000 to 150000.

Examples of the polyether polyol include compounds obtained by addition polymerization of cyclic ether compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1, 3-butanediol, 1, 4-butanediol, 1, 6-hexanediol, neopentyl glycol, glycerol, trimethylolethane, trimethylolpropane, sorbitol, sucrose, aconite, and trimellitic acid (Japanese text: fabryotic acid), phosphoric acid, ethylenediamine, diethylenetriamine, triisopropanolamine, pyrogallol, dihydroxybenzoic acid, hydroxyphthalic acid, 1,2, 3-propanetriol, and the like, and compounds obtained by ring-opening polymerization of the cyclic ether compounds with a cationic catalyst, a protonic acid, a Lewis acid, and the like, with at least 2 active hydrogen groups such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexene (Japanese text: taraxarun).

The polyester polyol is obtained by a dehydration condensation reaction of a diol compound, a dicarboxylic acid, a hydroxycarboxylic acid compound or the like, a ring-opening polymerization reaction of a cyclic ester compound such as epsilon-caprolactone or the like, and copolymerizing a polyester obtained by these reactions. Examples of the diol compound as a raw material of the polyester polyol include ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, dihydroxyethoxybenzene, 1, 4-cyclohexanediol, 1, 4-cyclohexanedimethanol, bisphenol a, hydrogenated bisphenol a, hydroquinone, and alkylene oxide adducts thereof.

Examples of dicarboxylic acids as the raw materials of the polyester polyol include succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, fumaric acid, 1, 3-cyclopentanedicarboxylic acid, 1, 4-cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 1, 4-naphthalenedicarboxylic acid, 2, 5-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, diphthalic acid, and 1, 2-bis (phenoxy) ethane-p, p' -dicarboxylic acid.

Examples of the hydroxycarboxylic acid as a raw material of the polyester polyol include p-hydroxybenzoic acid and p- (2-hydroxyethoxy) benzoic acid.

As the polycarbonate polyol, for example, a polycarbonate polyol obtained by reacting a carbonate with a low molecular weight polyol, preferably a linear aliphatic diol, can be used.

As the above-mentioned carbonate, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclic carbonate, diphenyl carbonate, and the like can be used.

Examples of the low molecular weight polyol capable of reacting with the above carbonate include lower molecular weight dihydroxy compounds such as ethylene glycol, diethylene glycol, triethylene glycol, 1, 2-propylene glycol, 1, 3-propylene glycol, dipropylene glycol, 1, 4-butanediol, 1, 3-butanediol, 1, 2-butanediol, 2, 3-butanediol, 1, 5-pentanediol, 1, 5-hexanediol, 2, 5-hexanediol, 1, 6-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 1, 9-nonanediol, 1, 10-decanediol, 1, 11-undecanediol, 1, 12-dodecanediol, 1, 4-cyclohexanediol, 1, 4-cyclohexanedimethanol, hydroquinone, resorcinol, bisphenol-A, bisphenol-F, 4' -biphenol, polyether polyols such as polyethylene glycol, polypropylene glycol, polyoxytetramethylene glycol, polyester polyols such as polyhexamethylene adipate, polyhexamethylene succinate, polycaprolactone, and the like.

The polycarbonate structure is preferably used in the range of 10 to 90 mass% relative to the total mass of the polyol and the polyisocyanate used in the production of the polycarbonate-based urethane resin.

The urethane resin has a hydrophilic group in order to impart dispersion stability in the aqueous liquid printing ink. As the hydrophilic group, a group commonly called an anionic group, a cationic group, or a nonionic group can be used, and among them, an anionic group or a cationic group is preferably used.

Examples of the anionic group include a carboxyl group, a carboxylate group, a sulfonate group, and among these, a carboxylate group and a sulfonate group which are partially or completely neutralized with a basic compound or the like are preferably used in order to maintain good water dispersibility.

Examples of the basic compound that can be used to neutralize the carboxyl group and the sulfonic acid group that are the anionic groups include organic amines such as ammonia, triethylamine, pyridine, and morpholine, alkanolamines such as monoethanolamine, and metal base compounds including Na, K, li, ca.

The cationic group may be, for example, a tertiary amino group. Examples of the acid that can be used for neutralizing a part or all of the tertiary amino groups include formic acid and acetic acid. As the quaternizing agent used in quaternizing a part or all of the tertiary amino groups, for example, dialkylsulfuric acids such as dimethyl sulfuric acid and diethyl sulfuric acid can be used.

Examples of the nonionic group include polyoxyalkylene groups such as polyoxyethylene, polyoxypropylene, polyoxybutylene, poly (oxyethylene-oxypropylene) and polyoxyethylene-polyoxypropylene. Among them, polyoxyalkylene groups having oxyethylene units are preferably used in view of further improving hydrophilicity.

When the hydrophilic group is present in an amount of 0.5 to 30% by mass based on the entire urethane resin, further excellent water dispersibility is imparted, and a range of 1 to 20% by mass is more preferable.

In addition, a crosslinking agent described later may be used depending on the desired physical properties. In the case of using the crosslinking agent, it is preferable to use, as the urethane resin, a urethane resin having a functional group capable of undergoing a crosslinking reaction with a functional group of the crosslinking agent.

Examples of the functional group include a carboxyl group, a carboxylate group, and the like which can be used as the hydrophilic group. The carboxyl group and the like contribute to the water-dispersible stability of the urethane resin in an aqueous medium, and also function as the functional group when they undergo a crosslinking reaction, and can undergo a part of the crosslinking reaction of the crosslinking agent.

In the case of using a carboxyl group or the like as the functional group, a urethane resin having an acid value of 2 to 55 is preferable as the urethane resin, and a urethane resin having an acid value of 15 to 50 is preferable from the viewpoint of improving the fastness. The acid value in the present invention is a theoretical value calculated based on the amount of the acid group-containing compound such as the carboxyl group-containing polyol used in the production of the urethane resin.

The urethane resin can be produced, for example, by reacting a polyol and a polyisocyanate with a chain extender as needed.

As the chain extender, polyamines, other active hydrogen atom-containing compounds, and the like can be used.

Examples of the polyamine include diamines such as ethylenediamine, 1, 2-propylenediamine, 1, 6-hexamethylenediamine, piperazine, 2, 5-dimethylpiperazine, isophoronediamine, 4' -dicyclohexylmethane diamine, 3' -dimethyl-4, 4' -dicyclohexylmethane diamine, and 1, 4-cyclohexanediamine; n-hydroxy methyl amino ethyl amine, N-hydroxy ethyl amino ethyl amine, N-hydroxy propyl amino propyl amine, N-ethyl amino ethyl amine, N-methyl amino propyl amine; diethylenetriamine, dipropylenetriamine, triethylenetetramine; hydrazine, N' -dimethylhydrazine, 1, 6-hexamethylenebishydrazine; succinic dihydrazide, adipic dihydrazide, glutaric dihydrazide, sebacic dihydrazide, isophthalic dihydrazide; beta-semicarbazide propionyl hydrazine, 3-semicarbazide-propyl-hydrazino formate, semicarbazide-3-semicarbazide methyl-3, 5-trimethylcyclohexane, preferably ethylenediamine is used.

Examples of the other active hydrogen-containing compounds include glycols such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1, 3-propanediol, 1, 3-butanediol, 1, 4-butanediol, hexamethylenediol, neopentyl glycol, sucrose, methylene glycol, glycerin, and sorbitol; bisphenol A, 4' -dihydroxybiphenyl, 4' -dihydroxydiphenyl ether, 4' -dihydroxydiphenyl sulfone, hydrogenated bisphenol A, hydroquinone, and other phenols, water, and the like.

The chain extender is preferably used in a range of 1.9 or less (equivalent ratio), more preferably in a range of 0.0 to 1.0 (equivalent ratio), and even more preferably in a range of 0.5 mass%, based on the equivalent weight of the amino group and the active hydrogen atom-containing group of the chain extender, relative to the equivalent weight of the isocyanate group of the urethane prepolymer obtained by reacting the polyol with the polyisocyanate.

The chain extender may be used when or after reacting the polyol with the polyisocyanate. In addition, the chain extender may be used when the urethane resin obtained above is dispersed in an aqueous medium to be made aqueous.

Examples of the polyhydric alcohol other than the above-mentioned polyhydric alcohol include polyhydric alcohols having relatively low molecular weights such as ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, dihydroxyethoxybenzene, 1, 4-cyclohexanediol, 1, 4-cyclohexanedimethanol, bisphenol A, hydrogenated bisphenol A, hydroquinone, alkylene oxide adducts thereof, glycerin, trimethylolethane, trimethylolpropane, sorbitol, pentaerythritol, and the like. These polyols may be used alone or in combination of 2 or more.

As the polyisocyanate that reacts with the above polyol to form a urethane resin, for example, 2 or more kinds of aromatic diisocyanates such as benzene diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, etc., aliphatic or aliphatic ring structure-containing diisocyanates such as hexamethylene diisocyanate, lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate, etc., can be used alone or in combination.

The binder resin is preferably 5 to 50% by mass in terms of the solid content of the aqueous liquid printing ink of the present invention. If the content is 5% by mass or more, the strength of the ink coating film is not lowered, and the substrate adhesion, water friction resistance and the like are also well maintained. Conversely, if the content is 50% by mass or less, the decrease in coloring power can be suppressed, and the increase in viscosity can be avoided, and the workability is not lowered. Of these, 5 to 40% by mass is more preferable, and 5 to 20% by mass is most preferable.

(surfactant)

In the present invention, a surfactant may be added depending on desired physical properties. The surfactant is not particularly limited, and surfactants commonly used in the art can be used, and among them, acetylene-based surfactants and alcohol alkoxylate-based surfactants are preferable.

Specific examples of the alkyne-based surfactant used in the present invention include 2, 5-dimethyl-3-hexyne-2, 5-diol, 3, 6-dimethyl-4-octyne-3, 6-diol, 2,4,7, 9-tetramethyl-5-decyne-4, 7-diol, 3, 5-dimethyl-1-hexyne-3-ol, 3-methyl-1-butyne-3-ol, 3-methyl-1-pentyne-3-ol, 3-hexyne-2, 5-diol, and 2-butyne-1, 4-diol. Further, commercially available Products include alkylene oxide non-modified acetylenic diol surfactants such as Surfynol 61, 82 and 104 (all of which are manufactured by Air Products Co., ltd.),

Alkylene oxide-modified acetylene glycol-based surfactants such as Surfynol 420, 440, 465, 485, TG, 2502, dynol 604, 607, surfynol SE, MD-20, OLFINE E1004, E1010, PD-004, EXP4300, PD-501, PD-502, SPC (all manufactured by Nissan chemical Co., ltd.), mountain and mountain ash, E40, E60, E81, E100, E200 (all manufactured by Kawaken Fine Chemicals Co., ltd.). Among them, alkylene oxide-modified acetylenic diol-based surfactants are preferable.

The alcohol alkoxylate-based surfactant used in the present invention is specifically DYNWET800 (BYK-Chemie Japan Co.).

These alkyne-based surfactants and alcohol alkoxylate-based surfactants may be used alone or in combination of 2 or more.

The total amount of the alkyne-based surfactant and/or the alcohol alkoxylate-based surfactant added is preferably 0.1 to 1% by mass of the total amount of the ink. These alkyne-based surfactants may be used alone or in combination of 2 or more, and if the total amount of the alkyne-based surfactant and/or the alcohol alkoxylate-based surfactant added is 0.1 mass% or more of the total amount of the ink, the coatability with the substrate is improved, and the adhesion with the substrate can be maintained. If the total amount of the alkyne-based surfactant and/or the alcohol alkoxylate-based surfactant added is 1 mass% or less of the total amount of the ink, the abrasion resistance, water-resistant friction and scratch resistance are not reduced.

Other acrylic polymer surfactants (e.g., POLYFLOWS-314 Co., ltd.) and modified silicone surfactants (e.g., POLYFLOW KL-401 Co., ltd.) may be used as needed.

For the above reasons, the total amount of the surfactant used is preferably 0.1 to 1% by mass of the total amount of the ink.

(wax)

In the present invention, wax may be added according to desired physical properties. The wax is preferably a carbon-based wax, and examples of the carbon-based wax include liquid paraffin, natural paraffin, synthetic paraffin, microcrystalline wax, polyethylene wax, fluorocarbon wax, ethylene-propylene copolymer wax, tetrafluoroethylene resin wax, and Fischer-Tropsch wax. These waxes may be used alone or in combination of 2 or more, and the total amount of these waxes added is preferably 0.5 to 5% by mass of the total amount of the ink. If the total amount of the wax added is 0.5 mass% or more of the total amount of the ink, abrasion resistance, water abrasion resistance and scratch resistance can be maintained. If the total amount of wax added is 5 mass% or less of the total amount of ink, adhesion to the substrate, abrasion resistance, water abrasion resistance, and scratch resistance can be maintained.

(curing agent)

In the present invention, a curing agent may be added according to desired physical properties. The acid-reactive curing agent used in the present invention is not particularly limited, and a known curing agent that can react with an acid group used in an aqueous medium can be used. Examples thereof include epoxy-based curing agents, carbodiimide-based curing agents, and oxazoline-based curing agents.

The epoxy curing agent is not particularly limited as long as it is a compound having at least 1 epoxy group. Examples of the epoxy curing agent include epoxy resins such as bisphenol a diglycidyl ether, modified bisphenol a diglycidyl ether, phenolic type glycidyl ether, glycerol polyglycidyl ether, and polyglycidyl ether.

The carbodiimide curing agent is not particularly limited as long as it is a compound having at least 1 carbodiimide group (-n=c=n-). As the carbodiimide-based curing agent, a polycarbodiimide compound having at least 2 carbodiimide groups is preferable.

The oxazoline-based curing agent is not particularly limited as long as it is a compound having an oxazoline skeleton. Specifically, the oxazoline-based curing agent includes eporos series manufactured by japan catalyst corporation.

Examples of the epoxy compound include diglycidyl ether of bisphenol a and its oligomer, diglycidyl ether of hydrogenated bisphenol a and its oligomer, diglycidyl phthalate, diglycidyl isophthalate, diglycidyl terephthalate, diglycidyl parahydroxybenzoate, diglycidyl tetrahydrophthalate, diglycidyl hexahydrophthalate, diglycidyl succinate, diglycidyl adipate, diglycidyl sebacate, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1, 4-butanediol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, polyalkylene glycol diglycidyl ether, triglycidyl trimellitate, triglycidyl isocyanurate, 1, 4-diglycidyl oxybenzene, diglycidyl ureide, triglycidyl ether, triglycidyl ethane triglycidyl ether, trimethylolpropane triglycidyl ether, pentaerythritol tetraglycidyl ether, and triglycidyl ether of an alkylene oxide adduct.

The amount of the curing agent used in the present invention is preferably in the range of 0.1 to 10.0 mass%, more preferably in the range of 0.5 to 9.0 mass%, in terms of the solid content of the total ink.

If the amount is 0.1 mass% or more, the effect as a curing agent can be obtained, whereas if it is 10.0 mass% or less, the substrate adhesion, abrasion resistance, and water friction resistance tend to be maintained.

In addition to the above, the present invention may contain extender pigments, pigment dispersants, leveling agents, antifoaming agents, plasticizers, infrared absorbers, ultraviolet absorbers, fragrances, flame retardants, and the like. Among them, fatty acid amides such as oleamide, stearamide, erucamide and the like for imparting abrasion resistance, slidability and the like, silicon-based and non-silicon-based antifoaming agents for suppressing foaming at the time of printing, various dispersants for improving wetting of pigments and the like are useful.

(method for producing aqueous liquid printing ink)

The aqueous liquid printing ink of the present invention is a pigment dispersion obtained by dispersing a mixture containing a pigment, an aqueous medium, a dispersant, a defoaming agent, and the like in a dispersing machine. The pigment dispersion obtained is mixed with additives such as a resin, an aqueous medium, and optionally a leveling agent, by stirring. As the dispersing machine, a bead mill, an Eiger mill, a sand mill, a γ mill, an attritor, and the like, which are generally used for the production of gravure ink and flexographic ink, are used.

When the aqueous liquid printing ink of the present invention is used as a flexographic ink, the viscosity thereof may be 7 to 25 seconds, more preferably 10 to 20 seconds, at 25 ℃ using Zahn Cup #4 manufactured by the clutch company. The surface tension of the obtained flexographic ink at 25℃is preferably 25 to 50mN/m, more preferably 33 to 43 mN/m. The lower the surface tension of the ink, the higher the wettability of the ink to a substrate such as a film, but if the surface tension is lower than 25mN/m, the dots adjacent to each other in the halftone dot portion tend to be easily connected to each other due to the wetting expansion of the ink, and the contamination of the printing surface called dot bridge tends to be caused. On the other hand, if the surface tension exceeds 50mN/m, the wettability of the ink to a substrate such as a film is lowered, which tends to cause dishing.

On the other hand, when the aqueous liquid printing ink of the present invention is used as a gravure ink, the viscosity thereof may be 7 to 25 seconds, more preferably 10 to 20 seconds, at 25 ℃ using Zahn Cup #3 manufactured by the clutch company. The surface tension of the obtained gravure ink at 25℃is preferably 25 to 50mN/m, and more preferably 33 to 43mN/m, similarly to the flexographic ink. The lower the surface tension of the ink, the higher the wettability of the ink to a substrate such as a film, but if the surface tension is lower than 25mN/m, there is a tendency that dots adjacent to each other in halftone dot portions are easily connected to each other due to the wetting and spreading of the ink, which tends to cause contamination of a printing surface called dot bridge. On the other hand, if the surface tension exceeds 50mN/m, the wettability of the ink to a substrate such as a film is lowered, which tends to cause dishing.

(printed matter)

The aqueous liquid printing ink of the present invention is printed on a substrate and a printing layer is provided to obtain a printed matter. In general, an ink is applied to a substrate by a gravure printing method or a flexography printing method, and dried and fixed by drying in an oven to obtain a printed layer. The drying temperature is usually about 40 to 60 ℃.

Examples of the substrate include films made of polyamide resins such as nylon 6, nylon 66, nylon 46, etc., thermoplastic resins such as polyethylene terephthalate (PET), polyethylene naphthalate, polypropylene terephthalate, polypropylene naphthalate, polybutylene terephthalate, polyester resins such as polybutylene naphthalate, biodegradable resins typified by aliphatic polyester resins such as polyhydroxycarboxylic acid such as polylactic acid, poly (ethylene succinate), poly (butylene succinate), etc., polyolefin resins such as polypropylene (PP), polyethylene, etc., polyimide resins, polyarylate resins, or mixtures thereof, and laminates thereof, and among these, films made of polyesters, polyamides, polyethylene, and polypropylene can be preferably used.

These films may be unstretched films or stretched films, and the production method thereof is not limited. The thickness of the base film is not particularly limited, and is usually in the range of 1 to 500. Mu.m.

In addition, if the printed surface of the film is subjected to corona discharge treatment, the adhesion to the substrate can be further improved, which is preferable. In addition, silica, alumina, and the like may be vapor deposited.

The substrate may be a paper such as a poster, a leaflet, a CD jacket, a direct mail advertisement, a booklet, a cosmetic, a drink, a pharmaceutical, a toy, or packaging for equipment, a coated paper, a paper such as a paper-like, a tissue, or a thick paper, or a synthetic paper.

In the laminate obtained by laminating a plurality of substrates including a printed matter having the print layer, the print layer may be located on the outermost layer of the laminate (so-called front print), or may be a laminate in which the print layer is located between a plurality of substrates (so-called back print). The aqueous liquid printing ink of the present invention is an ink which can be applied to any of the above-mentioned compositions.

[ example ]

Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, "part" means "part by mass" and "%" means "% by mass".

In the present invention, measurement of the weight average molecular weight (in terms of polystyrene) by GPC (gel permeation chromatography) was performed under the following conditions using HLC8220 system manufactured by eastern co.

Separation column: 4 TSKgelGMHHR-N manufactured by Tosoh corporation was used. Column temperature: 40 ℃. Mobile phase: and tetrahydrofuran, manufactured by Wako pure chemical industries, ltd. Flow rate: 1.0 ml/min. Sample concentration: 1.0 mass%. Sample injection amount: 100 microliters. A detector: differential refractometer.

The acid value of the acrylic resin represents the number of milligrams of potassium hydroxide required for neutralization of the acidic component contained in 1g of the resin, and the respective dried water-soluble resins were calculated by potentiometric titration with a potassium hydroxide-ethanol solution based on JIS K2501.

The glass transition temperature (Tg) is a calculated glass transition temperature, and is a value calculated by the following method.

(formula 1) 1/Tg (K) = (W1/T1) + (W2/T2) +. Cndot. Wn/Tn

(formula 2) Tg (°c) =tg (K) -273

W1, W2 in formula 1 the term Wn represents the mass% of each monomer relative to the total mass of the monomers used in the production of the polymer, T1, T2 Tn represents the glass transition temperature (K) of the homopolymer of each monomer. The values of T1, T2, ··Tn were as described in Polymer Handbook (fourth edition, code J.Brandrup, E.H.Immergut, E.A.Grulke).

The glass transition temperature of the homopolymer of each monomer was not shown in Polymer Hand Book, but was measured by a method according to JIS K7121 using a differential scanning calorimeter "DSC Q-100" (manufactured by TA instruments Co., ltd.). Specifically, for the polymer from which the solvent was completely removed by vacuum suction, the change in heat was measured at a temperature rise rate of 20 ℃/min in the range of-100 ℃ to +200 ℃, and the point at which a straight line equidistant from the straight line extending from each base line in the longitudinal axis direction intersects with the curve of the stepwise change portion of the glass transition was regarded as the glass transition temperature.

Synthesis example 1: preparation of Shell acrylic resin (Polymer a 1)

The reaction vessel was equipped with a stirrer, a thermometer, a dropping funnel, and a reflux tube, and 60.0 parts of n-propyl acetate was charged. While stirring under nitrogen atmosphere, the temperature was raised to 90 ℃. On the other hand, 36.0 parts of methyl methacrylate, 10.0 parts of ethyl methacrylate, 20.0 parts of n-butyl methacrylate, 10.0 parts of isobutyl methacrylate, 10.0 parts of 2-ethylhexyl acrylate, 14.0 parts of acrylic acid, and 1.0 part of azobisisobutyronitrile were dissolved in 40.0 parts of n-propyl acetate, and the mixture was added dropwise using a dropping funnel over 4 hours. After the completion of the dropwise addition, the reaction was further carried out for 6 hours. After the completion of the reaction, the reaction mixture was cooled, and 8.0 parts of 30% aqueous ammonia was added to the obtained acrylic resin solution to neutralize the aqueous ammonia. Ion-exchanged water was further added thereto, and solvent substitution was performed while heating, thereby obtaining an aqueous solution of an acrylic resin having a solid content of 55%. The acid value was 105mgKOH/g, tg was 65℃and the weight-average molecular weight was 16000.

[ Synthesis example 2: preparation of core-Shell acrylic emulsion (Ac 1)

A reaction vessel into which 121.2 parts of the aqueous acrylic resin solution prepared in Synthesis example 1 was charged was equipped with a stirrer, a thermometer, a dropping funnel, and a reflux tube, and 195.5 parts of ion-exchanged water was added. While stirring under nitrogen atmosphere, the temperature was raised to 75 ℃. Next, 30.0 parts of methyl methacrylate, 20.0 parts of ethyl methacrylate, 25.0 parts of n-butyl acrylate, 25.0 parts of 2-ethylhexyl acrylate, and 3.3 parts of 30% ammonium persulfate were added dropwise over 4 hours using a dropping funnel. After completion of the dropwise addition, the reaction was further carried out for 6 hours to obtain a core-shell type acrylic emulsion aqueous solution having a solid content of 40%. The acid value was 42mgKOH/g, tg was 10℃and the weight-average molecular weight was 1200000.

[ Synthesis example 3: preparation of polyurethane resin solution (Pu)

186.9 parts of PLACCEL 212 (polycaprolactone diol, hydroxyl value 90mgKOH/g, manufactured by Daicel chemical Co., ltd.) and 100.0 parts of isophorone diisocyanate (abbreviated as IPDI) were charged. This was stirred and heated to 110 ℃. After 1 hour, it was cooled to 80℃and 20.1 parts of dimethylolpropionic acid (abbreviated as DMPA), 0.3 part of dibutyltin dilaurate and 76.8 parts of ethyl acetate were added and reacted at 80℃for 2 hours. To this was added 18.1 parts of BURNOCK DN-980S (hexamethylene diisocyanate-based polyisocyanate, manufactured by DIC Co., ltd., NCO content: 20%) and 408 parts of methyl ethyl ketone (abbreviated as MEK). The NCO group content at this time was 4.9% in terms of solid content.

This was cooled to 30℃or lower, 15.2 parts of triethylamine was added, and 1293 parts of ion-exchanged water was then added to obtain an oil-in-water (O/W) type emulsion. Then, 234 parts of a 5% aqueous diethylenetriamine solution was slowly added, and after the addition was completed, the temperature was raised to 60℃and stirring was continued for 30 minutes.

Next, distillation was performed under reduced pressure to remove a part of the solvent and water.

It is a slightly milky translucent liquid, taken in small amounts in a test tube, and when tetrahydrofuran (abbreviated as THF) is added, it appears cloudy, indicating that crosslinking occurs and becomes insoluble. The nonvolatile content was 39.6%, the viscosity was 160cps, the pH was 7.7, and the average particle diameter was 28.5nm.

[ example 1 ]

10.0 parts of phthalocyanine blue (LDB 30 manufactured by DIC corporation), 40.0 parts of core-shell acrylic emulsion (Ac 1), and 30.0 parts of water shown in table 1 were mixed with stirring, and after kneading with a sand mill, 14.0 parts of water, 1.0 parts of SURFYNOL 420 (manufactured by riken chemical industry co., ltd.) as an alkylene oxide-modified acetylenic diol surfactant, and 5.0 parts of isobutanol were mixed with stirring, and the resultant blue printing ink was confirmed to be 20 seconds with Zahn Cup #3 (manufactured by clutch corporation).

[ examples 2 to 28 ]

According to the formulations shown in tables 1 and 2, 40.0 parts of a core-shell acrylic emulsion (Ac 1) was used to obtain a blue printing ink in the same manner as in example 1. The resultant blue printing ink was confirmed to be 20 seconds by Zahn Cup #3 (manufactured by Congo.).

Examples 29 to 53

According to the formulations shown in tables 3 and 4, 40.0 parts of polyurethane resin solution (Pu) was used instead of the core-shell acrylic emulsion (Ac 1), and a blue printing ink was obtained in the same manner as in example 1. The resultant blue printing ink was confirmed to be 20 seconds by Zahn Cup #3 (manufactured by Congo.).

[ examples 54 to 66 ]

According to the formulation shown in Table 5, 30.0 parts of titanium oxide (TITANIX JR-708, manufactured by TAYCA Co., ltd.) and 35.0 parts of a core-shell acrylic emulsion (Ac 1) were added in place of phthalocyanine blue, and a white printing ink was obtained in the same manner as in example 1. The obtained white printing ink was confirmed to be 20 seconds by Zahn Cup #3 (manufactured by Congo.).

[ examples 67 to 79 ]

According to the formulation shown in Table 6, 30.0 parts of titanium oxide (TITANIX JR-708, manufactured by TAYCA Co., ltd.) and 35.0 parts of polyurethane resin solution (Pu) were added to obtain a white printing ink in the same manner as in example 1. The obtained white printing ink was confirmed to be 20 seconds by Zahn Cup #3 (manufactured by Congo.).

Comparative examples 1 to 12

According to the formulation shown in Table 7, 10.0 parts of phthalocyanine blue (LDB 30 manufactured by DIC Co., ltd.) was added without using any organic solvent (A), and a blue printing ink was obtained in the same manner as in example 1. The resultant blue printing ink was confirmed to be 20 seconds by Zahn Cup #3 (manufactured by Congo.).

[ comparative examples 13 to 24 ]

According to the formulation shown in Table 8, 30.0 parts of titanium oxide (TITANIX JR-708, manufactured by TAYCA Co., ltd.) was added without using any organic solvent (A), and a white printing ink was obtained in the same manner as in example 1. The obtained white printing ink was confirmed to be 20 seconds by Zahn Cup #3 (manufactured by Congo.).

< preparation of printed matter >

On a treated surface of a biaxially stretched polyethylene terephthalate film (manufactured by TOYOBO Co., ltd., E5100 12 μm) having been subjected to corona discharge treatment on one surface, a compressed solid plate of Helio70 lines/cm was used by a gravure small-sized single-color printer, and printing was performed at a printing speed of 50 m/min with the blue printing ink or the white printing ink thus obtained to obtain a printed matter.

The produced blue printing ink, white printing ink and each of the obtained printed matter were used to evaluate foaming and leveling properties of the ink.

< foaming >)

The bubbling of the gravure mini-monochrome printer, which was idling at 50 m/min for 15 minutes after the production of the printed matter, was visually evaluated on the ink tray.

(evaluation criterion)

5: hardly observed bubbles, disappeared in the observation

4: bubble is below 30% of the ink surface

3: bubble is 50% or less of the ink surface

2: the bubbles are 80% or more of the ink surface

1: bubble covers the entirety of the ink surface

< leveling Property >)

The leveling property of the ink on the film printing surface was evaluated visually from the viewpoint of uniformity of the color shading.

(evaluation criterion)

5: no color shade and good leveling property

4: the shade of the color was slightly observed but hardly evident

3: the shade of color was observed, but to the extent that there was no problem in use.

2: light color part is generated in a stripe shape, and the leveling is poor

1: the light color part is produced in a large quantity in a stripe shape, and the leveling is very poor

The compositions of the respective printing inks and the evaluation results of the printed matter thereof are shown in tables 1 to 8.

[ Table 1 ]

[ Table 2 ]

[ Table 3 ]

[ Table 4 ]

[ Table 5 ]

[ Table 6 ]

[ Table 7 ]

[ Table 8 ]

From the above results, the aqueous liquid ink of the present invention is excellent in leveling property even when using a small amount of an organic solvent, and can be printed without foaming of the ink during printing, which is not inferior to a solvent-based ink.

Industrial applicability

The aqueous liquid ink of the present invention can be widely used as various intaglio printed matters and flexographic printed matters for industrial products such as food packaging materials, sanitary products, cosmetics, and electronic parts.

Claims (4)

1. An aqueous liquid printing ink for gravure printing of packaging materials, which contains a pigment, an acrylic resin or a urethane resin as a binder resin, and an aqueous medium, wherein the aqueous liquid printing ink satisfies (1) to (3),

the binder resin is 5 to 50 mass% in terms of the solid content of the aqueous liquid printing ink,

the viscosity of the aqueous liquid printing ink at the time of printing is 7 to 25 seconds at 25 ℃ using Zahn Cup #3 manufactured by the Co-Ltd,

(1) The total amount of the aqueous liquid printing ink contains 10 mass% or less of an organic solvent,

(2) The aqueous medium contains water and an organic solvent A with the solubility of 1g/100ml to 30g/100ml in 100ml of water at 25 ℃, wherein the organic solvent A is 1-butanol and/or isobutanol,

(3) The mass ratio of the organic solvent A to the other organic solvents B is that the organic solvent A: other organic solvents b=10: 90-100: 0.

2. The aqueous liquid printing ink according to claim 1, wherein the organic solvent a is contained in an amount of 3 mass% or more and 10 mass% or less based on the total amount of the aqueous liquid printing ink.

3. A printed matter obtained by printing the aqueous liquid printing ink according to claim 1 or 2 on a substrate.

4. A laminate comprising 1 or more printed layers on a plastic film, wherein at least 1 of the printed layers is the printed layer of the aqueous liquid printing ink according to claim 1 or 2.