Aqueous liquid compositions, coating solutions, laminates, and labels used for coating plastic substrates.

Abstract

The present invention provides an aqueous liquid composition for use in coating plastic substrates, which exhibits excellent storage stability, reduced powdering, adhesion, moisture resistance, blocking resistance, and plate cleaning properties. [Solution] An aqueous liquid composition for use in coating plastic substrates, comprising: an aqueous binder resin (A) selected from the group consisting of aqueous urethane resin, aqueous acrylic resin, and aqueous acrylic urethane resin; a large particle size wax (B); a small particle size wax (C); and a resin (D) having a polymerization chain including a hydrophobic portion and a hydrophilic portion including an acid group, wherein the large particle size wax (B) has an average particle size of 2.0 μm or more and 10.0 μm or less, and a penetration degree of 5 or more and 30 or less; the small particle size wax (C) has an average particle size of 0.1 μm or more and less than 2.0 μm, and a penetration degree of 0.1 or more and less than 15; and the solid content of resin (D) relative to the total mass of solid content of the aqueous liquid composition is 0.1 to 10% by mass.

Description

Technical Field

[0001] The present invention relates to an aqueous liquid composition, a coating liquid, a laminate, and a label used for coating a plastic substrate.

Background Art

[0002] Conventionally, label display has been used to display various information such as product names, logos of manufacturers, other designs, and raw materials on packaging containers for foods such as beverages, prepared foods, and bento boxes, daily necessities such as cosmetics and toiletries. Labels are generally manufactured by printing on a paper substrate or a plastic substrate. As labels using a plastic substrate, for example, labels printed on a heat-shrinkable film (shrink film) that shrinks by applying heat, and body-wrap labels that are formed by winding a printed strip of plastic film around a packaging container and attaching it are frequently used.

[0003] In recent years, compared with organic solvent-based inks, the demand for aqueous inks with less organic solvent emissions during printing and less residual solvent in the substrate has been increasing. For example, Patent Document 1 discloses an aqueous gravure printing ink composition for paper containers containing a colorant, an alkali-soluble water-soluble resin, an emulsion-type aqueous resin, a specific wax, and an aqueous medium. Further, Patent Document 2 discloses an aqueous varnish composition containing two types of waxes with different particle sizes and a silicone additive.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Water-based inks have a property of easily penetrating paper, and therefore, various studies have been conducted on water-based inks for printing on paper substrates. Conventional water-based inks adhere well to paper, but do not adhere well to plastic substrates. For this reason, it is difficult to use ink compositions for paper for coating plastic substrates. Furthermore, the inventors of this invention have found that in the case of labels printed with ink on plastic substrates, there is a problem in the process of attaching them to packaging containers where the ink coating comes into contact with the metal roll (guide roll) that guides the moving film (label), causing a phenomenon in which powdery foreign matter adheres to the metal roll (also called "powdering"). The present invention aims to provide an aqueous liquid composition for use in coating plastic substrates that exhibits excellent storage stability, reduced powdering, adhesion, moisture friction resistance, blocking resistance, and plate cleaning properties. [Means for solving the problem]

[0006] The present invention has the following aspects. [1] An aqueous liquid composition used for coating plastic substrates, A water-based binder resin (A) is at least one selected from the group consisting of water-based urethane resin, water-based acrylic resin, and water-based acrylic urethane resin, Large particle size wax (B) and small particle size wax (C), The material contains a resin (D) having a polymer chain containing a hydrophobic portion and a hydrophilic portion containing an acid group, The aforementioned large-particle wax (B) has an average particle size of 2.0 μm or more and 10.0 μm or less, and a penetration degree of 5 or more and 30 or less. The aforementioned small particle size wax (C) has an average particle size of 0.1 μm or more and less than 2.0 μm, and a penetration degree of 0.1 or more and less than 15. The acid value of the aforementioned resin (D) is 1 to 245 mg KOH / g. An aqueous liquid composition used for coating plastic substrates, wherein the content of the resin (D) relative to the total mass of the solids in the aqueous liquid composition is 0.1 to 18% by mass. [2] The aqueous liquid composition according to [1], wherein the aqueous binder resin (A) comprises both the aqueous urethane resin and the aqueous acrylic urethane resin, and the mass ratio of the solid content of the aqueous urethane resin to the aqueous acrylic urethane resin is 1:0.3 to 1:20. [3] The aqueous liquid composition according to [1], wherein the aqueous binder resin (A) contains the aqueous acrylic resin, and the aqueous acrylic resin contains both a water-soluble acrylic resin and a water-dispersible acrylic resin, and the mass ratio of the solid content of the water-soluble acrylic resin to the water-dispersible acrylic resin is 1:0.8 to 1:25. [4] The aqueous liquid composition according to any one of [1] to [3], wherein the mass ratio of the solid content of the large-particle wax to the small-particle wax is 1:0.1 to 1:10. [5] The aqueous liquid composition according to any one of [1] to [4], wherein the resin (D) comprises one or more selected from the group consisting of polyethylene glycol-modified styrene maleic acid copolymer, styrene maleic acid copolymer, phosphate ester of polyether-modified styrene maleic acid copolymer, and styrene maleic acid copolymer having a phosphate ester. [6] An aqueous liquid composition according to any one of [1] to [5], for use with a curing agent. [7] The aqueous liquid composition according to [6], wherein the curing agent comprises one or more selected from the group consisting of carbodiimide curing agents, aziridine curing agents, and isocyanate curing agents. [8] A coating solution comprising the aqueous liquid composition described in any one of the above items [1] to [7]. [9] A laminate having a plastic substrate and a coating layer on the plastic substrate consisting of the coating liquid described in [8].

[10] A label obtained using the laminate described in [9] above.

[11] A label for food and beverages, as described in

[10] .

[12] The label on the body of the bottle, as described in

[10] . [Effects of the Invention]

[0007] According to the present invention, there can be provided an aqueous liquid composition for coating on a plastic substrate, which is excellent in storage stability, powder spraying reduction property, adhesion, wet rubbing resistance, blocking resistance, and plate washing property, and a coating liquid, a laminate, and a label using the same.

Brief Description of Drawings

[0008] [Figure 1] It is a cross-sectional view schematically showing an example of the laminate of the present invention. [Figure 2] It is a cross-sectional view schematically showing an example of the laminate of the present invention.

Modes for Carrying Out the Invention

[0009] Hereinafter, the present invention will be described in detail. The following embodiments are merely illustrative for explaining the present invention, and it is not intended to limit the present invention only to these embodiments. The present invention can be implemented in various modes without departing from the gist thereof. The following definitions of terms apply throughout this specification and the claims.

[0010] "Aqueous" in the aqueous liquid composition means containing an aqueous medium. "Aqueous medium" means a liquid medium containing water. "Liquid medium" means a volatile liquid such as water or an organic solvent. "Volatile content" means components that volatilize, such as water and organic solvents, among the components contained in the aqueous liquid composition. Specifically, the heating residue obtained by a measuring method conforming to JIS K 5601-1-2:2008 is taken as the solid content (also referred to as non-volatile content), and the rest is taken as the volatile content. "(Meth)acrylate" is a general term for "acrylate" and "methacrylate". "~" indicating a numerical range means including the numerical values described before and after it as the lower limit value and the upper limit value. The lower and upper limit values of the numerical ranges disclosed in this specification can be arbitrarily combined to form a new numerical range.

[0011] The weight average molecular weight of the aqueous binder resin is the weight average molecular weight in terms of standard polystyrene molecular weight and is measured by gel permeation chromatography (GPC). The glass transition temperature of the aqueous binder resin is measured in accordance with JIS K 7121:2012 as follows. That is, using a differential scanning calorimeter, the glass transition temperature is determined from the intersection of the baseline and the tangent of the endothermic curve in the curve (DSC curve) obtained by heating 10 mg of the aqueous binder resin from -100 °C to 160 °C at a rate of 20 °C / min. The acid value of the aqueous binder resin is the amount of potassium hydroxide required to neutralize acid groups such as carboxyl groups per 1 g of the solid content of the sample, expressed in milligrams, and is measured in accordance with JIS K 5601-2-1:1999.

[0012] The average particle diameter of the wax is the particle diameter (median diameter: D50) of the number-based cumulative frequency of 50% calculated from the obtained particle diameter distribution by measuring the particle diameter distribution based on the number by the Coulter counter method. The Coulter counter method is a method of electrically measuring the particle diameter and particle diameter distribution of particles from the change in the electrical signal when the particles pass through pores by passing the wax particles dispersed in the solution through the pores. The penetration of the wax is measured by a method compliant with JIS K-2235-6.3-93. Specifically, the sample is kept at a constant temperature, a load of 100 g is applied to a specified needle, and the needle is allowed to penetrate into the sample for 5 seconds, and the depth of penetration of the needle is measured. The temperature of the sample is 25 °C.

[0013] ≪Aqueous liquid composition used for coating a plastic substrate≫ The aqueous liquid composition (hereinafter also simply referred to as "aqueous liquid composition") used for coating a plastic substrate according to an embodiment of the present invention contains an aqueous binder resin (A), a large particle diameter wax (B), a small particle diameter wax (C), and a resin (D). A water-based liquid composition can be mixed with a coloring agent to create a water-based ink. In other words, a water-based liquid composition means a composition that does not contain a coloring agent. A water-based liquid composition without a coloring agent can also be used as a water-based medium or water-based varnish, which are color-adjusting liquids for water-based inks. The aqueous liquid composition of this embodiment is used for coating plastic substrates. The type of plastic substrate can be appropriately selected depending on the application and is not particularly limited. Details of the plastic substrate will be described later.

[0014] <Water-based binder resin (A)> The aqueous binder resin (A) is at least one selected from the group consisting of aqueous urethane resin, aqueous acrylic resin, and aqueous acrylic urethane resin. In this specification, "water-based urethane resin" is a general term encompassing "water-soluble urethane resin" and "water-dispersible urethane resin (urethane resin emulsion, urethane resin dispersion)." The same applies to "water-based acrylic resin" and "water-based acrylic urethane resin." The water-based binder resin (A) contributes to improving the adhesion between the coated layer and the plastic substrate. It also contributes to the cleanability of the coating solution on the printing plate.

[0015] [Water-based urethane resin] Examples of aqueous urethane resins include reaction products of polyvalent isocyanate compounds and polyol compounds. A polyvalent isocyanate compound is an organic compound having at least two isocyanate groups in one molecule. A polyol compound is an organic compound having at least two hydroxyl groups in one molecule.

[0016] Examples of polyvalent isocyanate compounds include aliphatic, alicyclic, and aromatic polyvalent isocyanate compounds. Specific examples of polyvalent isocyanate compounds include aliphatic diisocyanates such as trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methyl caproate; hydrogenated diisocyanates. Diphenylmethane diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-cyclopentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate), 4,4'-methylenebis(cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexyl Alicyclic diisocyanates such as san diisocyanate, 1,4-bis(isocyanate-methyl)cyclohexane, 1,3-bis(isocyanate-methyl)cyclohexane; m-phenylenediisocyanate, p-phenylenediisocyanate, 4,4'-diphenyldiisocyanate, 1,5-naphthalenediisocyanate, 4,4'-diphenylmethanediisocyanate, 2,4- or 2,6-tolylenediisocyanate, 4,4'-toluidinediisocyanate, dianisidinediisocyanate, 4, Examples include aromatic diisocyanates such as 4'-diphenyl ether diisocyanate; polyvalent isocyanate compounds having allophanate, nurate, or biuret structures obtained by polymerizing the above diisocyanates; triisocyanates such as 1,3,5-triisocyanatebenzene, 2,4,6-triisocyanatetoluene, and 1,3,5-triisocyanatehexane; and polyisocyanates such as 4,4'-diphenyldimethylmethane-2,2'-5,5'-tetraisocyanate. These polyvalent isocyanate compounds may be used individually or in combination of two or more.

[0017] Examples of polyol compounds include polyether polyols obtained by polymerizing oxirane compounds such as ethylene oxide, propylene oxide, butylene oxide, and tetrahydrofuran using low molecular weight polyols such as ethylene glycol, propylene glycol, trimethylolpropane, and glycerin as initiators; ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, octanediol, 1,9-nonanediol, 1,8-nonanediol, 1,4-cyclohexanediol, 1,4 Examples include polyester polyols obtained by dehydrating and condensing saturated or unsaturated glycols such as cyclohexanedimethanol, bisphenol A, and hydrogenated bisphenol A with dibasic acids such as adipic acid, maleic acid, fumaric acid, phthalic anhydride, isophthalic acid, terephthalic acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, and suberic acid, or their corresponding acid anhydrides or dimer acids; polyolefin polyols such as polyethylene polyols and polypropylene polyols; polyether ester polyols obtained by reacting the dibasic acids or their dialkyl esters with the polyether polyols; and polycarbonate polyols obtained by reacting the glycols with methyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, etc. These polyol compounds may be used individually or in combination of two or more.

[0018] The weight-average molecular weight of the aqueous urethane resin is preferably 3,000 to 100,000, more preferably 7,000 to 90,000, and even more preferably 20,000 to 80,000, from the viewpoint of particularly excellent balance between the blocking resistance of the coating layer and adhesion to the plastic substrate. If the weight-average molecular weight of the aqueous urethane resin is above the lower limit, the blocking resistance of the coating layer is improved, and if it is below the upper limit, the adhesion of the coating layer to the plastic substrate is improved.

[0019] The glass transition temperature of the aqueous urethane resin is preferably -10 to 130°C, more preferably 20 to 120°C, and even more preferably 40 to 100°C, from the viewpoint of particularly excellent balance between the blocking resistance of the coating layer and adhesion to the plastic substrate. If the glass transition temperature of the aqueous urethane resin is above the lower limit, the blocking resistance of the coating layer is improved, and if it is below the upper limit, the adhesion of the coating layer to the plastic substrate is improved.

[0020] The aqueous urethane resin preferably has an acid value, preferably 1 to 60 mg KOH / g, and more preferably 1 to 50 mg KOH / g, from the viewpoint of having an excellent balance of adhesion of the coating layer to the plastic substrate, crosslinking density with the curing agent, and stability of the coating liquid when the curing agent is added. The aqueous urethane resin having an acid value provides good water solubility. Furthermore, when using the curing agent (E) described later in combination, a robust coating layer can be obtained by crosslinking with the curing agent.

[0021] Aqueous urethane resins can be obtained, for example, by reacting a polyvalent isocyanate compound with a polyol compound using a known method. Alternatively, a silanol group may be introduced by reacting a hydrolyzable silicon group-containing compound with the reaction product of a polyvalent isocyanate compound and a polyol compound. A hydrolyzable silicon group-containing compound is a compound containing a hydrolyzable silicon group, and it is preferable that it further contains an active hydrogen group in addition to the hydrolyzable silicon group. Hydrolyzable silicon groups include groups in which the hydrolyzable group produced upon hydrolysis, either in the presence or absence of a silanol condensation catalyst, is bonded to a silicon atom. Examples of hydrolyzable groups include hydrogen atoms, halogen atoms, alkoxy groups, acyloxy groups, ketoximate groups, amino groups, amide groups, aminooxy groups, mercapto groups, and alkenyloxy groups. Typically, one to three hydrolyzable groups are bonded to a single silicon atom. Examples of active hydrogen groups include amino groups, hydroxyl groups, and mercapto groups.

[0022] Commercially available water-based urethane resins may be used. Examples of commercially available products include "Hydran WLS-210" from DIC Corporation; "Neo Sticker 400" and "Neo Sticker 200" from Nikka Chemical Co., Ltd.; "Superflex 500M" from Daiichi Kogyo Seiyaku Co., Ltd.; and "Takerack W-5661," "Takerack WS-5000," "Takerack W-6010," "Takerack WS-5100," "Takerack WS-4000," and "Takerack W-635" from Mitsui Chemicals, Inc. Water-based urethane resin may be used alone or in combination of two or more types.

[0023] [Water-based acrylic urethane resin] Examples of aqueous acrylic urethane resins include reaction products of a polyvalent isocyanate compound, a polyol compound, and a hydroxyl group-containing (meth)acrylate, or reaction products of a polyvalent isocyanate compound and a hydroxyl group-containing (meth)acrylate. Examples of polyvalent isocyanate compounds include those previously exemplified in the description of aqueous urethane resins. Examples of polyol compounds include those previously exemplified in the description of aqueous urethane resins.

[0024] Examples of hydroxyl group-containing (meth)acrylates include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Furthermore, as the water-based acrylic urethane resin, a core-shell type resin having an acrylic resin core and a urethane resin shell may be used.

[0025] The weight-average molecular weight of the aqueous acrylic urethane resin is preferably 5,000 to 120,000, more preferably 10,000 to 100,000, and even more preferably 10,000 to 80,000, from the viewpoint of particularly excellent balance between solvent resistance, water resistance, blocking resistance, and adhesion to the plastic substrate of the coating layer. If the weight-average molecular weight of the aqueous acrylic urethane resin is above the lower limit, the solvent resistance and blocking resistance of the coating layer are improved, and if it is below the upper limit, the adhesion of the coating layer to the plastic substrate is improved.

[0026] The glass transition temperature of the aqueous acrylic urethane resin is preferably -30 to 100°C, more preferably -30 to 90°C, and even more preferably -20 to 90°C, from the viewpoint of particularly excellent balance between the blocking resistance of the coating layer and adhesion to the plastic substrate. If the glass transition temperature of the aqueous acrylic urethane resin is above the lower limit, the blocking resistance of the coating layer is improved, and if it is below the upper limit, the adhesion of the coating layer to the plastic substrate is improved.

[0027] The aqueous acrylic urethane resin preferably has an acid value, preferably 1 to 100 mg KOH / g, and more preferably 1 to 60 mg KOH / g, from the viewpoint of having an excellent balance between the adhesion of the coating layer to the plastic substrate and the stability of the coating solution when a curing agent is added. The aqueous acrylic urethane resin having an acid value provides good water solubility. Furthermore, when using the curing agent (E) described later in combination, a robust coating layer can be obtained by crosslinking with the curing agent.

[0028] Aqueous acrylic urethane resins can be obtained by reacting a polyvalent isocyanate compound with a polyol compound with a hydroxyl group-containing (meth)acrylate, or a polyvalent isocyanate compound with a hydroxyl group-containing (meth)acrylate, by known methods.

[0029] Commercially available water-based acrylic urethane resins may be used. Examples of commercially available products include "WEM-200U," "WEM-505C," and "WEM-3000" from Taisei Fine Chemical Co., Ltd., and "NeoPack E-315" from Covestro Coating Resins. Water-based acrylic urethane resin may be used alone or in combination of two or more types.

[0030] [Water-based acrylic resin] "Water-based acrylic resin" is a general term encompassing both "water-soluble acrylic resin" and "water-dispersible acrylic resin (acrylic resin emulsion, acrylic resin dispersion)." Acrylic resin is a polymer or copolymer containing (meth)acrylate units. Examples include a homopolymer of (meth)acrylate, a copolymer of two or more (meth)acrylates, and a copolymer of (meth)acrylate and a monomer other than (meth)acrylate. The ratio of (meth)acrylate units to the total mass of all monomer units constituting the acrylic resin is preferably 10 to 100% by mass, and more preferably 20 to 100% by mass.

[0031] Examples of (meth)acrylates include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and lauryl (meth)acrylate; cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate; aryl (meth)acrylates such as phenyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; and hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. These (meth)acrylates may be used individually or in combination of two or more.

[0032] Examples of monomers other than (meth)acrylates include conjugated diene compounds such as 1,3-butadiene, isoprene, and chloroprene; aromatic vinyl compounds such as styrene, α-methylstyrene, halogenated styrene, and divinylbenzene; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; acrylamides such as N,N-dimethyl(meth)acrylamide and N,N-diethyl(meth)acrylamide; unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, maleic acid, and fumaric acid; and unsaturated carboxylic acid esters such as diethyl maleate, dibutyl maleate, dibutyl fumarate, diethyl itaconate, and dibutyl itaconate. These monomers may be used individually or in combination of two or more.

[0033] [Water-soluble acrylic resin] The acid value of the water-soluble acrylic resin is preferably 10 to 300 mg KOH / g, more preferably 50 to 280 mg KOH / g, even more preferably 80 to 260 mg KOH / g, and particularly preferably 100 to 250 mg KOH / g from the viewpoint of having an excellent balance between the adhesion of the coating layer to the plastic substrate and the stability of the coating solution when a curing agent is added.

[0034] The weight-average molecular weight of the water-soluble acrylic resin is preferably 1,000 to 500,000, more preferably 3,000 to 200,000, and even more preferably 5,000 to 100,000, from the viewpoint of having an excellent balance of pigment dispersibility, coating liquid fluidity, resolubility, blocking resistance of the coating layer, and adhesion to the plastic substrate.

[0035] The glass transition temperature of the water-soluble acrylic resin is preferably 0 to 140°C, more preferably 10 to 130°C, even more preferably 20 to 120°C, and particularly preferably 50 to 110°C from the viewpoint of having an excellent balance between the blocking resistance of the coating layer and adhesion to the plastic substrate.

[0036] Water-soluble acrylic resins are obtained by polymerizing monomer components that include (meth)acrylate and, if necessary, monomers other than (meth)acrylate. The polymerization method is not particularly limited, but examples include polymerizing monomer components in the presence of a known radical polymerization initiator using solution polymerization, bulk polymerization, emulsion polymerization, etc. The water-soluble acrylic resin may be of the self-crosslinking type.

[0037] Commercially available water-soluble acrylic resins may be used. Examples of commercially available products include those manufactured by Seikoh PMC Co., Ltd., such as "Hyros-X PL-1231", "Hyros-X BL-2300", "Hyros-X NL-1253", "Hyros-X M-30", "Hyros-X YL-1098", "Hyros-X QL-1358", "Hyros-X GL-2439", "Hyros-X VL-1147", and "Hyros-X NL-1189"; and those manufactured by BASF Japan Ltd., such as "Joncryl 52J", "Joncryl PDX-6157", "Joncryl 60J", "Joncryl 70J", "Joncryl JDX-6180", "Joncryl HPD-196", "Joncryl HPD-96J", "Joncryl PDX-6137A", "Joncryl 6610", "Joncryl JDX-6500", and "Joncryl PDX-6102B". Water-soluble acrylic resins may be used individually or in combination of two or more types.

[0038] [Water-dispersible acrylic resin] As a water-dispersible acrylic resin, for example, a core-shell type resin having acrylic resin in the shell portion can be suitably used.

[0039] The acid value of the water-dispersible acrylic resin is preferably 1 to 200 mg KOH / g, more preferably 5 to 150 mg KOH / g, and even more preferably 10 to 100 mg KOH / g, from the viewpoint of having an excellent balance between the adhesion of the coating layer to the plastic substrate and the stability of the coating solution when a curing agent is added.

[0040] The weight-average molecular weight of the water-dispersible acrylic resin is preferably 5,000 to 1,150,000, more preferably 10,000 to 500,000, and even more preferably 20,000 to 390,000, from the viewpoint of having an excellent balance of solvent resistance, water resistance, blocking resistance, and adhesion to the plastic substrate of the coating layer.

[0041] The glass transition temperature of the water-dispersible acrylic resin is preferably -20 to 100°C, more preferably -15 to 90°C, even more preferably -10 to 80°C, and particularly preferably 0 to 70°C. From the viewpoint of having an excellent balance between the blocking resistance of the coating layer and adhesion to the plastic substrate, 5 to 60°C is most preferred.

[0042] Water-dispersible acrylic resins can be produced by known methods, such as the polymer emulsifier method or the two-stage emulsion polymerization method. For example, they can be produced using a method that synthesizes core-shell type water-dispersible acrylic resins using the polymer emulsifier method.

[0043] Commercially available water-dispersible acrylic resins can also be used. Examples of commercially available water-dispersible acrylic resins include those manufactured by Seikoh PMC Co., Ltd., such as "Hyros-X QE-1042", "Hyros-X M-141", "Hyros-X TE-1048", "Hyros-X KE-1062", "Hyros-X X-436", "Hyros-X KE-1060", "Hyros-X HE-1335", "Hyros-X RE-1075", "Hyros-X PE-1304", "Hyros-X KE-2536", "Hyros-X J-140A", "Hyros-X TE-1102", "Hyros-X RE-218", "Hyros-X NE-2009", "Hyros-X JE-1056", "Hyros-X KE-1148", "Hyros-X ME-2039", "Hyros-X UE-1051", and "Hyros-X Product names manufactured by BASF Japan Ltd.: "PE-1126", "Joncryl PDX-7616A", "Joncryl PDX-7356", "Joncryl PDX-7777", "Joncryl PDX-7357", "Joncryl PDX-7182", "Joncryl PDX-7326", "Joncryl PDX-7732", "Joncryl PDX-7741", "Joncryl PDX-7787", "Joncryl PDX-7734", "Joncryl PDX-7615", "Joncryl PDX-77 Examples include "75", "Joncryl PDX-7692", "Joncryl PDX-7630A", "Joncryl PDX-7158", "Joncryl 352D", "Joncryl PDX-7199", "Joncryl PDX-7358", "Joncryl PDX-7667", "Joncryl PDX-7700", "Joncryl PDX-7696", "Joncryl PDX-7780", "Joncryl PDX-7177", "Joncryl PDX-7430", and product names from Aica Kogyo Co., Ltd. such as "Ultrasole A-25", "Ultrasole A-35", "Ultrasole A-40", "Ultrasole A-50", "Ultrasole C-63", "Ultrasole C-70", "Ultrasole D-32", "Ultrasole D-40", "Ultrasole GP-300", and "Ultrasole UL-1097". Water-dispersible acrylic resins may be used individually or in combination of two or more types.

[0044] <wax> As the wax to be contained in the aqueous liquid composition, a combination of a large-particle wax (B) and a small-particle wax (C) having different average particle sizes and penetration degrees is used. The materials of the large-particle wax (B) and the small-particle wax (C) may be the same or different. From the viewpoint of reducing powdering and compatibility, it is preferable that they be the same.

[0045] Examples of materials for the large-particle wax (B) and small-particle wax (C) include animal and plant-based waxes such as beeswax, lanolin wax, whale wax, candelilla wax, carnauba wax, rice wax, wood wax, and jojoba oil; mineral and petroleum-based waxes such as montane wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, and petrolatum; synthetic hydrocarbon waxes such as Fischer-Tropsch wax, polyethylene wax, oxidized polyethylene wax, and oxidized polypropylene wax; modified waxes such as montane wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives; hydrogenated waxes such as hydrogenated castor oil and hydrogenated castor oil derivatives; polytetrafluoroethylene wax (PTFE); and carboxylic acid esters or partial esters of polyhydric alcohols obtained by the reaction of polyhydric alcohols (glycerin, pentaerythritol, etc.) with long-chain fatty acids. The large-particle wax (B) and small-particle wax (C) may be manufactured by known methods, may be natural products, or may be commercially available products. The large-particle wax (B) or small-particle wax (C) may also be obtained by adjusting the particle size of a commercially available wax compound.

[0046] Examples of polyethylene waxes include high-density polymerized polyethylene, low-density polymerized polyethylene, oxidized polyethylene, acid-modified polyethylene, and special monomer-modified polyethylene. Fischer-Tropsch wax is a wax produced using carbon monoxide and hydrogen as raw materials by the Fischer-Tropsch process, and has a nearly saturated, unbranched, linear molecular structure. Paraffin wax can be produced by known methods of producing paraffin wax, such as solvent fractionation, distillation fractionation, and urea dewaxing.

[0047] Commercially available polyethylene waxes include the following products from Mitsui Chemicals, Inc.: "Chemipearl W100", "Chemipearl W200", "Chemipearl W300", "Chemipearl W308", "Chemipearl W400", "Chemipearl W401", "Chemipearl W500", "Chemipearl W640", "Chemipearl W700", and "Chemipearl W800"; and the following products from BYK: "CERAFLOUR925", "CERAFLOUR925N", "CERAFLOUR927N", and "CERAFLOUR929". Examples include "CERAFLOUR929N", "CERAFLOUR950", "CERAFLOUR960", "CERAFLOUR961", "CERAFLOUR988", "CERAFLOUR991", "CERAFLOUR1000", "AQUACER531", "AQUACER537", "AQUACER552", "AQUACER840", "AQUACER1547", "AQUAMAT208", and the BASF Japan product name "Joncryl Wax 4".

[0048] <Large particle size wax (B)> Large particle size wax (B) has an average particle size of 2.0 μm or more and 10.0 μm or less, and a penetration degree of 5 or more and 30 or less. The average particle size of the large-particle wax (B) is preferably 2.0 μm or more and less than 8.5 μm from the viewpoint of reducing powdering and improving adhesion. From the viewpoint of blocking resistance, it is preferably 8.5 μm or more and 10 μm or less. If the average particle size of the large-particle wax (B) is above the lower limit of the above range, powdering reduction is improved. In addition, moisture friction resistance is improved. If it is below the upper limit of the above range, powdering reduction and moisture friction resistance are improved. In addition, blocking resistance is improved. If the average particle size of the large-particle wax (B) is less than 2.0 μm, powdering reduction and moisture friction resistance are poor, and if it is greater than 10.0 μm, powdering reduction, blocking resistance, and moisture friction resistance are poor. The penetration degree of the large-particle wax (B) is preferably 5 or more and less than 7 from the viewpoint of moisture friction resistance. From the viewpoint of reducing powdering and improving adhesion, it is more preferably 7 or more and 28 or less. If the penetration degree of the large-particle wax (B) is above the lower limit of the above range, powdering reduction is improved. In addition, moisture friction resistance is improved. If the penetration degree is below the upper limit of the above range, powdering reduction is improved. In addition, blocking resistance is improved. If the penetration degree of the large-particle wax (B) is less than 5, powdering reduction and moisture friction resistance are poor, and if it is greater than 30, powdering reduction and blocking resistance are poor.

[0049] <Small particle size wax (C)> Small particle size wax (C) has an average particle size of 0.1 μm or more and less than 2.0 μm, and a penetration degree of 0.1 or more and less than 15. The average particle size of the small-particle wax (C) is preferably 0.1 μm or more and less than 0.8 μm from the viewpoint of blocking resistance, preferably 0.8 μm or more and less than 1.2 μm from the viewpoint of powder reduction and adhesion, and preferably 1.2 μm or more and less than 2.0 μm from the viewpoint of moisture friction resistance. If the average particle size of the small-particle wax (C) is above the lower limit of the above range, powder reduction and moisture friction resistance are improved. If it is below the upper limit of the above range, powder reduction is improved. In addition, moisture friction resistance is improved. If the average particle size of the small-particle wax (C) is less than 0.1 μm, powder reduction and moisture friction resistance are poor, and if it is 2.0 μm or more, powder reduction and moisture friction resistance are poor. The penetration degree of the small-particle wax (C) is preferably 0.1 or more and less than 12 from the viewpoint of moisture friction resistance, and more preferably 2.5 or more and less than 8 from the viewpoint of reducing powdering and improving adhesion. From the viewpoint of blocking resistance, it is preferably 8 or more and less than 15. If the penetration degree of the small-particle wax (C) is above the lower limit of the above range, powdering reduction is improved. In addition, blocking resistance is improved. If it is below the upper limit of the above range, powdering reduction and moisture friction resistance are improved. If the penetration degree of the small-particle wax (C) is less than 0.1, blocking resistance and powdering reduction are poor, and if it is 15 or more, powdering reduction and moisture friction resistance are poor.

[0050] <Resin (D)> Resin (D) is an additive (powder reduction aid) that, when used together with large-particle wax (B) and small-particle wax (C), contributes to reducing the powdering phenomenon (powdering reduction property). The powdering phenomenon occurs during the labeling process, in which a long laminate consisting of a coated layer on a plastic film (plastic substrate) is cut and attached to a packaging container. When the coated layer comes into contact with the metal roll (guide roll) that guides the long laminate, powdery foreign matter adheres to the metal roll. This powdery foreign matter is thought to originate from the solid components in the coated layer. When powdering occurs, it becomes necessary to remove the foreign matter adhering to the metal roll. In addition, foreign matter on the metal roll may migrate and adhere to the laminate, in which case it becomes necessary to remove the foreign matter from the laminate as well. Therefore, by reducing the powdering phenomenon, the removal work required for these products becomes unnecessary, and productivity in the labeling process for packaging containers can be improved.

[0051] Resin (D) is a compound having a polymer chain with a hydrophobic portion and a hydrophilic portion containing an acid group. The hydrophilic portion may be a constituent unit of the polymer chain, an atomic group bonded to the polymer chain, or both.

[0052] Examples of hydrophobic portions present in polymer chains include constituent units derived from hydrophobic monomers and polyolefin chains. Examples of hydrophobic monomers include ethylenically unsaturated monomers having an aromatic ring. Specific examples include styrene, α-methylstyrene, vinyltoluene, and their derivatives. Examples of polyolefin chains include polyethylene chains and polypropylene chains.

[0053] The hydrophilic portion of resin (D) contains acidic groups. Hydrophilic portions present in polymerization chains include constituent units derived from acid-group-containing ethylenically unsaturated monomers. Specific examples of acid-group-containing ethylenically unsaturated monomers include maleic anhydride, maleic acid, maleic acid monoesters, and their derivatives. Examples of hydrophilic portions bonded to the polymerization chain include phosphate esters.

[0054] Examples of resin (D) include styrene-maleic acid copolymers, polyethylene glycol-modified styrene-maleic acid copolymers, polypropylene glycol-modified styrene-maleic acid copolymers, phosphate esters of polyether-modified styrene-maleic acid copolymers, and styrene-maleic acid copolymers having phosphate esters. The copolymers or resins used as resin (D) also possess surfactant and dispersion functions. Resin (D) may be used alone or in combination of two or more types.

[0055] For example, it is preferable that resin (D) includes resin (D1), which is one or more resins selected from the group consisting of polyethylene glycol-modified styrene maleic acid copolymer, styrene maleic acid copolymer, phosphate ester of polyether-modified styrene maleic acid copolymer, and styrene maleic acid copolymer having a phosphate ester. The ratio of the total mass (solid content) of resin (D1) to the total mass (solid content) of resin (D) contained in the aqueous liquid composition may be, for example, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, and may also be 100% by mass.

[0056] The acid value of resin (D) is 1 to 245 mgKOH / g, with 1 to 220 mgKOH / g being more preferable from the viewpoint of reducing powdering, moisture friction resistance, and plate cleaning performance. If the acid value of resin (D) is less than 1 mgKOH / g, powdering reduction, adhesion, moisture friction resistance, and plate cleaning performance are poor, and if it is greater than 245 mgKOH / g, powdering reduction, moisture friction resistance, blocking resistance, and plate cleaning performance are poor.

[0057] The molecular weight of resin (D) is preferably 3,000 to 50,000, and more preferably 5,000 to 30,000 from the viewpoint of improving two-component stability. If the molecular weight of resin (D) is above the lower limit of the above range, blocking resistance is improved, and if it is below the upper limit, adhesion is improved.

[0058] The resin (D) may be a synthetic product manufactured by a known method, or a commercially available product may be used. Examples of commercially available products include BYK's "DISPERBYK-190," "DISPERBYK-194N," and "DISPERBYK-2010," and EVONIC's "TEGODISPERS 655" and "TEGODISPERS 760W."

[0059] <Aqueous medium> The aqueous liquid composition of this embodiment includes an aqueous medium. Examples of aqueous media include water and mixed solvents of water and organic solvents. The organic solvent in the mixed solvent is not particularly limited as long as it is soluble in water, but examples include alcohol-based solvents such as methanol, ethanol, propanol, n-butanol, and i-butanol; ketone-based solvents such as acetone; and glycol ether-based solvents such as propylene glycol monomethyl ether. These organic solvents may be used individually or in combination of two or more. The water content relative to the total mass of the aqueous medium is preferably 60 to 100% by mass, more preferably 70 to 100% by mass, and even more preferably 80 to 100% by mass.

[0060] <Optional ingredients> The aqueous liquid composition may contain optional components other than those listed above, as needed. As optional components, known additives for coating liquids for plastic substrates can be used. Examples of additives include thickeners, anti-settling agents, UV absorbers, antioxidants, leveling agents, viscoelastic modifiers, surface tension modifiers, rheology modifiers, light stabilizers, defoamers, lubricants, dispersants, stabilizers, pH adjusters, fillers, antifungal agents, antistatic agents, metal nanoparticles, magnetic powders, and the like. The optional components may be used individually or in combination of two or more.

[0061] <Composition of aqueous liquid composition> [Water-based binder resin (A)] The solid content of the aqueous binder resin (A) relative to the total mass of solids in the aqueous liquid composition (also called total solids) is preferably 40 to 90% by mass, and more preferably 45 to 88% by mass. If the solid content of the aqueous binder resin (A) in the aqueous liquid composition is above the lower limit of the above range, the drying performance of the coating film during coating is improved. In addition, the adhesion between the coating layer and the plastic substrate is excellent. If it is below the upper limit of the above range, the fluidity of the aqueous liquid composition is improved.

[0062] From the viewpoint of moisture resistance, friction resistance, and blocking resistance, it is preferable to use both water-based urethane resin and water-based acrylic urethane resin as the water-based binder resin (A). When the aqueous binder resin (A) contains both aqueous urethane resin and aqueous acrylic urethane resin, the mass ratio of the solids of the aqueous urethane resin to the aqueous acrylic urethane resin, expressed as aqueous urethane resin:aqueous urethane resin, is preferably 1:0.3 to 1:20, and more preferably 1:0.3 to 1:5 from the viewpoint of moisture friction resistance and blocking resistance. From the viewpoint of reducing powdering, moisture friction resistance, and blocking resistance, 1:0.3 to 1:1.5 is particularly preferred. When the mass ratio of aqueous acrylic urethane resin to aqueous urethane resin is above the lower limit of the above range, moisture friction resistance and blocking resistance are improved, and when it is below the upper limit, two-component stability is improved.

[0063] When the aqueous binder resin (A) contains both a water-soluble acrylic resin and a water-dispersible acrylic resin, the mass ratio of the solids of the water-soluble acrylic resin to the water-dispersible acrylic resin, expressed as water-soluble acrylic resin:water-dispersible acrylic resin, is preferably 1:0.8 to 1:25 from the viewpoint of moisture friction resistance and blocking resistance. When the mass ratio of the water-dispersible acrylic resin to the water-soluble acrylic resin is above the lower limit of the above range, moisture friction resistance and blocking resistance are improved, and when it is below the upper limit, moisture friction resistance and blocking resistance are improved.

[0064] The aqueous liquid composition may contain known aqueous binder resins other than aqueous urethane resin, aqueous acrylic resin, and aqueous acrylic urethane resin, to the extent that it does not impair the effects of the present invention. For example, the total amount of solids of aqueous urethane resin, aqueous acrylic resin, and aqueous acrylic urethane resin relative to the total mass of solids of aqueous binder resin (A) may be, for example, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, and may also be 100% by mass. When the aqueous binder resin (A) contains both aqueous urethane resin and aqueous acrylic urethane resin, the total amount of solids of the aqueous urethane resin and aqueous acrylic urethane resin relative to the total mass of solids of the aqueous binder resin (A) may be, for example, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, and may also be 100% by mass. When the aqueous binder resin (A) contains both a water-soluble acrylic resin and a water-dispersible acrylic resin, the total amount of solids of the water-soluble acrylic resin and the water-dispersible acrylic resin relative to the total mass of solids of the aqueous binder resin (A) may be, for example, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more, and may also be 100% by mass.

[0065] [Large particle size wax (B)] The solid content of the large-particle wax (B) relative to the total mass of solids in the aqueous liquid composition is preferably 3% to 25% by mass, more preferably 3% to 18% by mass, even more preferably 7% to 12% by mass from the viewpoint of improving adhesion, and even more preferably 3% to less than 7% by mass from the viewpoint of improving blocking resistance. When the solid content of the large-particle wax (B) in the total solids of the aqueous liquid composition is above the lower limit of the above range, powder reduction, moisture friction resistance, and blocking resistance are improved, and when it is below the upper limit of the above range, moisture friction resistance is improved.

[0066] [Small particle size wax (C)] The solid content of small-particle wax (C) relative to the total mass of solids in the aqueous liquid composition is preferably 3% to 35% by mass, more preferably 3% to 30% by mass, even more preferably 15% to less than 23% by mass from the viewpoint of improving adhesion, and even more preferably 23% to 29% by mass from the viewpoint of improving blocking resistance. When the solid content of small-particle wax (C) in the total solids of the aqueous liquid composition is above the lower limit of the above range, powder reduction, moisture friction resistance, and blocking resistance are improved, and when it is below the upper limit of the above range, powder reduction and blocking resistance are improved.

[0067] (Ratio of large-particle wax to small-particle wax) The mass ratio of large-particle wax to small-particle wax solids contained in the aqueous liquid composition, i.e., large-particle wax:small-particle wax, is preferably 1:0.1 to 1:10, more preferably 1:1 to 1:3 from the viewpoint of improving adhesion, and more preferably greater than 1:3 to 1:8 from the viewpoint of improving blocking resistance. When the mass ratio of small-particle wax to large-particle wax is 0.1 or more within the above range of 1:0.1, two-component stability, adhesion, and plate cleaning performance are improved. When the mass ratio of small-particle wax to large-particle wax is 10 or less within the above range of 1:10, powder reduction, adhesion, moisture friction resistance, and blocking resistance are improved.

[0068] [Resin (D)] The solid content of resin (D) relative to the total mass of solids in the aqueous liquid composition is 0.1 to 18% by mass, preferably 1 to 10% by mass, and more preferably 3 to 7% by mass from the viewpoint of reducing powdering and improving adhesion. If the solid content of resin (D) in the total solids of the aqueous liquid composition that does not contain pigment is above the lower limit of the above range, two-component stability and powdering reduction are improved. In addition, plate cleaning performance is improved. If it is below the upper limit of the above range, powdering reduction is improved. In addition, adhesion between the coating layer and the plastic substrate, moisture friction resistance, and blocking resistance are improved. If the solid content of resin (D) in the total solids of the aqueous liquid composition is less than 0.1% by mass, two-component stability, plate cleaning performance, and powdering reduction are poor, and if it is more than 10% by mass, powdering reduction, adhesion, moisture friction resistance, and blocking resistance are poor.

[0069] [Total solids] The total solids content of the aqueous liquid composition is preferably 10% to 60% by mass, and more preferably 15% to 50% by mass, based on the total mass of the aqueous liquid composition. If the total solids content of the aqueous liquid composition is above the lower limit of the above range, the drying performance of the coating film during application is improved. If it is below the upper limit of the above range, the fluidity of the aqueous liquid composition is improved.

[0070] <Method for producing aqueous liquid composition> The aqueous liquid composition of this embodiment can be obtained by mixing, for example, an aqueous binder resin (A), a large particle size wax (B), a small particle size wax (C), a resin (D), and an optional component, such that each component is present in a desired amount. The method of mixing each component is not particularly limited, and the components can be mixed by various methods.

[0071] <Hardening agent (E)> The aqueous liquid composition of this embodiment may be used together with a curing agent (E). For example, a coating liquid may be prepared by mixing the aqueous liquid composition with the curing agent (E), and the resulting coating liquid may be applied to a plastic substrate. Using a hardening agent (E) further improves the coating film's properties, such as water resistance and abrasion resistance, as well as its adhesion to the plastic substrate.

[0072] As the curing agent (E), any known curing agent in the field of coating liquids can be used, such as isocyanate-based curing agents, blocked isocyanate-based curing agents, carbodiimide-based curing agents, oxazoline-based curing agents, epoxy-based curing agents, and aziridine-based curing agents. Among these, isocyanate-based curing agents, carbodiimide-based curing agents, and aziridine-based curing agents are preferred from the viewpoint of two-component stability. These hardening agents (E) may be used individually or in combination of two or more types. Among these, isocyanate-based curing agents are particularly excellent in terms of pot life, while aziridine-based curing agents are particularly excellent in terms of resistance to both wet and dry friction.

[0073] Specific examples of isocyanate-based curing agents include the polyvalent isocyanate compounds previously exemplified in the explanation of water-based acrylic urethane resins. Commercially available isocyanate-based curing agents include: Mitsui Chemicals, Inc.'s product names "Takenate WD-720", "Takenate WD-725", "Takenate WD-726", "Takenate WD-730", "Takenate WD-220", "Takenate XWD-HS7", and "Takenate XWD-HS30"; Nippon Polyurethane Industries, Ltd.'s product names "Aquanate 100", "Aquanate 110", "Aquanate 200", and "Aquanate 210"; Asahi Kasei Corporation's product names "Duranate WB40-100", "Duranate WB40-80D", "Duranate WT20-100", "Duranate WT30-100", "Duranate WL70-100", "Duranate WR80-70P", and "Duranate WE50-100"; and Bayer Material Sciences' product name "Bayhydur Examples include "3100", "Bayhydur 302", "Bayhydur 304", "Bayhydur 305", "Bayhydur XP2451 / 1", "Bayhydur XP2487 / 1", "Bayhydur XP2547", "Bayhydur XP2655", and "Bayhydur XP2700"; BASF products such as "Basonat HW100", "Basonat HA100", and "Basonat HW1180PC", and Dainichi Seika Kogyo Co., Ltd.'s product name "Hydric FC Hardener". Isocyanate-based curing agents may be used individually or in combination of two or more types.

[0074] Specific examples of blocked isocyanate curing agents include blocks formed by blocking agents for isocyanate curing agents (e.g., alcohol compounds, phenolic compounds, oxime compounds, lactam compounds, pyrazole compounds, and active methylene compounds). These blocked isocyanate-based curing agents may be used individually or in combination of two or more types.

[0075] Carbodiimide-based curing agents are compounds containing two or more carbodiimide groups in a single molecule. Specific examples of carbodiimide-based curing agents include poly(4,4'-diphenylmethanecarbodiimide), poly(dicyclohexylmethanecarbodiimide), and poly(diisopropylcarbodiimide). Commercially available carbodiimide-based curing agents include the "Carbodilite" series from Nisshinbo Chemical Inc. and the "AB Hardener" product from Dainichi Seika Kogyo Co., Ltd. These carbodiimide-based curing agents may be used individually or in combination of two or more types.

[0076] Oxazoline-based curing agents are compounds containing two or more oxazoline groups in one molecule. Specific examples of oxazoline-based curing agents include polyhydric oxazolines such as 2,2'-bis-(2-oxazoline), 2,2'-methylene-bis-(2-oxazoline), and 2,2'-(1,4-phenylene)-bis(2-oxazoline), as well as polymers or copolymers having oxazoline group-containing monomer units such as 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. Each oxazoline group-containing monomer may be used individually, or two or more may be used together. Furthermore, copolymers of an oxazoline group-containing monomer with another monomer copolymerizable with this monomer may also be used. A commercially available oxazoline-based curing agent is the "Epocross" series manufactured by Nippon Shokubai Co., Ltd. These oxazoline-based curing agents may be used individually or in combination of two or more types.

[0077] Epoxy curing agents are compounds containing two or more epoxy groups in a single molecule. Specific examples of epoxy curing agents include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, triglycidylaminophenol, biphenyl diglycidyl ether, triglycidyl isocyanurate, polyglycidyl (meth)acrylate, and copolymers of glycidyl (meth)acrylate with vinyl monomers copolymerizable thereto. Commercially available epoxy curing agents include the "jER" series from Mitsubishi Chemical Corporation and the "Denacol EX" series from Nagase ChemteX Corporation. These epoxy hardeners may be used individually or in combination of two or more types.

[0078] Aziridine-based curing agents are compounds containing two or more aziridine groups in a single molecule. Specific examples of aziridine-based curing agents include 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] and 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane. Commercially available aziridine-based curing agents include the "Chemitite" series manufactured by Nippon Shokubai Co., Ltd. and the "Hydric RA Hardener" manufactured by Dainichi Seika Kogyo Co., Ltd. These aziridine-based curing agents may be used individually or in combination of two or more types.

[0079] When using an aqueous liquid composition in combination with a curing agent (E), if the amount of curing agent (E) used is too small, the curing reaction may not proceed sufficiently, and if it is too large, the water resistance of the coating layer may decrease. To minimize these problems, it is preferable to mix the curing agent (E) and the aqueous liquid composition such that the solid content of the curing agent (E) is 0.1 to 10 parts by mass, more preferably 0.3 to 7 parts by mass, and even more preferably 0.5 to 7 parts by mass, with respect to 100 parts by mass of the total mass of the aqueous liquid composition. Furthermore, by keeping the proportion of the curing agent within the above range, it is possible to obtain an aqueous liquid composition with excellent fluidity of the coating liquid during coating and a good pot life of the coating liquid after mixing with the curing agent.

[0080] Water-based ink The aqueous ink of this embodiment comprises the aqueous liquid composition of this embodiment and a colorant. Furthermore, if necessary, in addition to the optional components listed above, additives for aqueous inks may be appropriately included. Examples of colorants include conventionally known organic and inorganic pigments used in general inks, paints, and recording materials. Organic pigments include phthalocyanine pigments (phthalocyanine blue, phthalocyanine green, etc.), azo pigments (monoazo, condensed azo, etc.), slene pigments (anthraquinone, perinone, perylene, thioindigo, etc.), quinacridone pigments, dioxazine pigments, isoindolinone pigments, pyrrolopyrrole pigments, aniline black, organic fluorescent pigments, and other organic pigments; and inorganic pigments include natural products (clay, etc.), ferrocyanides (Prussian blue, etc.), sulfides (zinc sulfide, etc.), sulfates, oxides (titanium dioxide, chromium oxide, zinc oxide, iron oxide, etc.), hydroxides (aluminum hydroxide, etc.), silicates (ultramarine, etc.), carbonates, carbon (carbon black, graphite, etc.), metal powders (aluminum powder, bronze powder, zinc powder, etc.), and calcined pigments.

[0081] Examples of additives for water-based inks include dispersants, surface modifiers, and defoamers.

[0082] The colorant content is preferably 1 to 60% by mass relative to the total mass of the water-based ink. When using organic pigments as colorants, the content of the organic pigment is preferably 1 to 35% by mass relative to the total mass of the aqueous ink. When using inorganic pigments such as titanium dioxide or barium sulfate as colorants, the inorganic pigment content is preferably 10 to 60% by mass relative to the total mass of the water-based ink.

[0083] When using a water-based ink and a curing agent (E) in combination, it is preferable to mix them so that the solid content of the curing agent (E) is 0.1 to 10 parts by mass, more preferably 0.3 to 7 parts by mass, and even more preferably 0.5 to 7 parts by mass, per 100 parts by mass of the total mass of the water-based ink.

[0084] ≪Water-based medium, water-based varnish≫ The aqueous medium of this embodiment consists of the aqueous liquid composition of this embodiment. The aqueous medium is used as a hue-adjusting liquid that does not contain colorants, and is mixed with aqueous ink. However, the aqueous medium is not limited to color matching; it is also preferable to use it as an aqueous varnish. In the combination of aqueous medium and aqueous ink to be mixed, the combination of the aqueous medium and aqueous ink of this embodiment is preferred, and it is more preferable that the composition of the aqueous liquid composition in the aqueous ink and the composition of the aqueous medium are the same. When using a mixture of aqueous ink and aqueous medium in combination with a curing agent (E), it is preferable to mix the two such that the solid content of the curing agent (E) is 0.1 to 10 parts by mass, more preferably 0.3 to 7 parts by mass, and even more preferably 0.5 to 7 parts by mass, per 100 parts by mass of the total mass of the mixture of aqueous ink and aqueous medium. When using a water-based varnish and a hardener (E) in combination, it is preferable to mix them so that the solid content of the hardener (E) is 0.1 to 10 parts by mass, more preferably 0.3 to 7 parts by mass, and even more preferably 0.5 to 7 parts by mass, per 100 parts by mass of the total mass of the water-based varnish.

[0085] <Coating liquid> The coating liquid of this embodiment is a coating liquid used for coating plastic substrates, which can be used as an aqueous ink containing the aqueous liquid composition of this embodiment and a colorant, a hue-adjusting medium that does not contain a colorant, or an aqueous varnish not limited to color matching.

[0086] <Laminate> Figures 1 and 2 show an example of a laminate having a plastic substrate and a coating layer made of a coating liquid according to one embodiment of the present invention. In this specification, "coating layer made of a coating liquid" means a layer made of components from which volatile components of the coating liquid have been removed. Note that the dimensional ratios in Figures 1 and 2 differ from the actual dimensions for the sake of explanation. The laminate 10 in Figure 1 comprises a plastic film 11 which is a plastic substrate and a coating layer 12 provided on one surface of the plastic film 11. The laminate 20 in Figure 2 comprises a plastic film 21 which is a substrate, a first coating layer 22 provided on one surface of the plastic film 21, and a second coating layer 23 provided on top of the first coating layer. In the laminates 10 and 20, the coating layer 12 and the second coating layer 23 may be the outermost layers on the viewing side, or the plastic films 11 and 21 may be the outermost layers on the viewing side.

[0087] When the laminate is attached to a packaging container as a plastic label, it is preferable that the plastic films 11 and 21 are attached so that they are on the outside of the coating layer 12 and the second coating layer 23, that is, so that the first coating layer 12 and the second coating layer 23 are on the inside (the side that contacts the packaging container). Alternatively, other coating layers may be provided on the surfaces of the plastic films 11 and 21 by coating them with a composition containing a matting agent, such as a varnish composition or an extender pigment. Here, the surface of plastic film 11 means the surface opposite to the surface on which the coating layer 12 is provided. The surface of plastic film 21 means the surface opposite to the surface on which the first coating layer 22 is provided. Furthermore, the surface on which the coating layer 12 is provided on plastic film 11 is considered the back surface of plastic film 11, and the surface on which the first coating layer 22 is provided on plastic film 21 is considered the back surface of plastic film 21.

[0088] <Plastic substrate> The type of plastic film 11, 21, which is the plastic substrate, can be appropriately selected according to the application of the laminate 10, 20, and is not particularly limited. Examples of materials for the plastic films 11 and 21 include polyesters such as polyethylene terephthalate (PET), amorphous polyethylene terephthalate (A-PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polylactic acid; polyolefins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polypropylene (PP); cellulose such as cellophane; polystyrene (PS); ethylene-vinyl acetate copolymer resin; ethylene-vinyl alcohol copolymer resin; polyamide (Ny); polycarbonate; polyimide; and polyvinyl chloride.

[0089] When the laminates 10 and 20 are used as heat-shrinkable labels (shrink labels), the plastic films 11 and 21 are preferably uniaxially shrinkable polystyrene film, uniaxially shrinkable PET film, uniaxially shrinkable polyolefin film, or uniaxially shrinkable polyvinyl chloride film. When the laminates 10 and 20 are used as roll labels, the plastic films 11 and 21 can be either stretched or unstretched plastic films, such as biaxially oriented PP film (OPP film) and unstretched PP film.

[0090] The plastic films 11 and 21 may have a single-layer structure or a laminated structure. That is, the plastic films 11 and 21 may be single-layer films or laminated films. If the plastic films 11 and 21 are laminated films, they may be constructed by laminating two or more films of the same type, or by laminating two or more films of different types. Examples of preferred film combinations include a combination in which a polyester film is used on the surface side of plastic films 11 and 21 and a polystyrene film or polyolefin film is used on the back side of plastic films 11 and 21, and a combination in which a cyclic polyolefin film is used on the surface side of plastic films 11 and 21 and a polyethylene film or polypropylene film is used on the back side of plastic films 11 and 21.

[0091] The plastic films 11 and 21 may be subjected to surface treatments such as corona discharge treatment, plasma treatment, flame treatment, or solvent treatment, as needed.

[0092] The thickness of the plastic films 11 and 21 is preferably 5 to 100 μm, more preferably 12 to 60 μm, and even more preferably 12 to 50 μm.

[0093] (Coating layer, second coating layer) Hereinafter, the coating layer formed using the coating liquid containing the aqueous liquid composition of this embodiment described above will also be referred to as the "main coating layer." The coating layer 12 of the laminate 10 is the main coating layer. In the laminate 20, at least the second coating layer 23 is the main coating layer. The presence of the main coating layer as the outermost layer of the laminate provides a powdering reduction effect. The thickness of the coating layer is preferably 0.2 to 3.0 μm, more preferably 0.3 to 2.0 μm, and even more preferably 0.3 to 1.5 μm.

[0094] (First coating layer) The first coating layer 22 may be the main coating layer formed using a coating liquid containing the aqueous liquid composition of this embodiment described above, or it may be a coating layer formed using a different coating liquid. It is preferable that both the first coating layer 22 and the second coating layer 23 are the main coating layers. In the laminate 20, for example, the first coating layer 22 is a coating layer formed using an ink composition to impart design and functionality to the laminate 20 (hereinafter also referred to as the "color coating layer"), and the second coating layer 23 is a white coating layer formed using a white ink composition for the purpose of protecting the color coating layer and providing opacity. The first coating layer 22 may be a single layer or a laminated layer. The total thickness of the first coating layer 22 is preferably 0.2 to 15 μm, more preferably 0.3 to 10 μm, and even more preferably 0.3 to 8 μm.

[0095] <Method for manufacturing laminates> The method for manufacturing the laminate includes the step of applying a coating liquid containing the aqueous liquid composition of this embodiment onto a plastic substrate to form a coating layer. The manufacturing method for the laminate 10 in Figure 1 includes the step of forming a coating layer 12 on one surface of the plastic film 11 using a coating liquid. The manufacturing method for the laminate 20 in Figure 2 includes the step (1) of forming a first coating layer 22 on one surface of the plastic film 21 using a first coating liquid, and the step (2) of forming a second coating layer 23 on the first coating layer 22 using a second coating liquid.

[0096] In the manufacturing method of the laminate 10 shown in Figure 1, for example, a coating liquid is applied to one surface of the plastic film 11 and dried to form a coating layer 12. Alternatively, after applying the coating liquid to one surface of the plastic film 11 and drying to form the coating layer 12, the same coating liquid may be applied again (overcoat).

[0097] The coating method for the coating solution is not particularly limited, and known coating methods such as gravure printing, flexographic printing, brush coating, gravure coater method, die coater method, bar coater method, spray coating method, flow coating method, dip coating method, spin coating method, and curtain coating method can be used. Among these, flexographic printing is preferred due to its high quality and productivity.

[0098] The drying method is not particularly limited as long as it can remove the aqueous medium contained in the coating liquid applied to one surface of the plastic film 11, but examples include vacuum drying, pressure drying, heat drying, and air drying. The heating temperature is preferably 30 to 150°C, and more preferably 40 to 120°C.

[0099] The manufacturing method for the laminate 20 shown in Figure 2 includes steps (1) and (2) described above in this order. In step (1), for example, a coating liquid is applied to one surface of the plastic film 21 and dried to form a first coating layer 22. In step (2), for example, a coating liquid is applied on top of the first coating layer 22 and dried to form a second coating layer 23. Step (1) may be performed once or repeated two or more times. That is, the coating liquid may be applied in multiple layers. Step (2) may be performed once or repeated two or more times. That is, the coating liquid may be applied in multiple layers. The coating method and drying method in steps (1) and (2) can be the same as those used for the manufacturing method of the laminate 10.

[0100] <Variation> The laminate is not limited to the embodiments described above. For example, in the laminate 10 shown in Figure 1, the coating layer 12 is provided over the entire surface of one side of the plastic film 11, but the coating layer 12 may be provided on only a part of one side of the plastic film 11. In this case, it is preferable that another coating layer be provided in the area of ​​one side of the plastic film 11 where the coating layer 12 is not provided. The other coating layer may be, for example, a layer formed from a varnish composition.

[0101] Similarly, in the case of the laminate 20 shown in Figure 2, the second coating layer 23 is provided on the entire surface of one side of the first coating layer 22, but the second coating layer 23 may be provided on a part of the surface of one side of the first coating layer 22. In this case, it is preferable that another coating layer be provided in the area of ​​one side of the first coating layer 22 where the second coating layer 23 is not provided. Examples of other coating layers include layers formed from a varnish composition.

[0102] Furthermore, in the case of the laminate 10 shown in Figure 1, another coating layer may be provided on the surface of the coating layer 12 opposite to the plastic film 11. The other coating layer may be, for example, a layer formed from a varnish composition. Similarly, in the case of the laminate 20 shown in Figure 2, another coating layer may be provided on the surface of the second coating layer 23 opposite to the first coating layer 22. The other coating layer may be, for example, a layer formed from a varnish composition.

[0103] <label> A label according to one embodiment of the present invention is obtained using the laminate of this embodiment described above. The uses of labels include various labels attached to packaging containers for food and beverages such as drinks, condiments, prepared foods, and bento boxes, as well as daily necessities such as cosmetics. They are particularly suitable as labels for items whose packaging containers are plastic bottles, for example, as labels for bottled food and beverages. Examples of bottled food and beverages include beverages, liquid condiments (dressings, noodle soup bases, soy sauce, liquid miso, etc.), and cooking oils. The label can take the form of, for example, a wrap-around label or a shrink-wrap label.

[0104] <Effects and Effects> As shown in the examples described later, by using the aqueous liquid composition of this embodiment to form a coating layer (printed layer) on a plastic substrate, the powdering phenomenon during the label application process can be reduced. By using a water-based binder resin (A), along with large-particle wax (B) and small-particle wax (C) having specific average particle size and penetration degree, and by using a specific resin (D) in a specific amount, the powdering phenomenon was reduced, particularly by using two different sizes of wax instead of just one.

[0105] Furthermore, the aqueous liquid composition, aqueous ink, and aqueous medium of this embodiment exhibit good storage stability, and the coating solution using the curing agent also exhibits good stability (two-component stability). Furthermore, the coating solution containing the aqueous liquid composition of this embodiment exhibits excellent adhesion of the coating layer to the plastic substrate, as well as superior moisture resistance, friction resistance, and plate cleaning properties. Furthermore, water-based inks generally dry more slowly than oil-based inks, and if the water-based medium in the coating layer is not sufficiently dried, blocking is likely to occur when the laminate (printed material) is wound up after printing. However, the coating solution containing the water-based liquid composition of this embodiment also exhibits excellent blocking resistance. [Examples]

[0106] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. In the following, "NV" refers to non-volatile content (solids). Unless otherwise specified, "%" in the unit of content means "mass%". Unless otherwise specified, "parts" means "parts by mass".

[0107] [Raw materials used] <Water-based binder resin (A)> The following compounds were used as aqueous binder resin (A) and comparative component (A'). A-1: Water-based urethane resin (manufactured by Mitsui Chemicals, Inc., product name "Takelac W-5661", solids content 35% by mass). Hereafter also referred to as "U". A-2: Water-based acrylic urethane resin (manufactured by Covestro Coating Resins, product name "NeoPack E-315", solids content 35% by mass). Hereafter also referred to as "AU". A-3: Water-soluble acrylic resin (BASF Corporation, product name "Joncryl 70J", solids content 30% by mass). Hereafter also referred to as "A". A-4: Water-dispersible acrylic resin (acrylic resin emulsion, manufactured by Seikoh PMC, product name "Hyros X-ME-2039", solids content 48.5% by mass). Hereafter also referred to as "AE". A'-5: Polyester resin (manufactured by Unitika Corporation, product name "Elitel KT-8803", solids content 30% by mass, Tg 65℃, number average molecular weight 15000). A'-6: Chlorinated polyolefin (manufactured by Nippon Paper Industries, product name "Supercron E-415", solid content 30% by mass).

[0108] <Large particle size wax (B)> The following large-particle wax (B) and comparative component (B'), manufactured in Manufacturing Example 1 described below, were used. ·B-1: Average particle size 2.5μm, penetration degree 10. ·B-2: Average particle size 2.2μm, penetration 8.8. ·B-3: Average particle size 9.0μm, penetration rate 10. ·B-4: Average particle size 2.5μm, penetration 5.8. ·B-5: Average particle size 2.8μm, penetration 25. ·B'-6: Average particle size 1.0μm, penetration 12. ·B'-7: Average particle size 15.0μm, penetration 15. ·B'-8: Average particle size 2.5μm, penetration 1. ·B'-9: Average particle size 3.0μm, penetration 40.

[0109] <Small particle size wax (C)> The following large-particle wax (C) and comparative component (C'), manufactured in Manufacturing Example 1 described below, were used. ·C-1: Average particle size 1μm, penetration degree 3. ·C-2: Average particle size 0.2μm, penetration 2.7. ·C-3: Average particle size 1.8μm, penetration 2.9. ·C-4: Average particle size 1μm, penetration 0.5. ·C-5: Average particle size 0.8μm, penetration degree 13. ·C'-6: Average particle size 0.05μm, penetration degree 3. ·C'-7: Average particle size 3.0μm, penetration 3.2. ·C'-8: Average particle size 0.7μm, penetration 0.05. ·C'-9: Average particle size 1.3μm, penetration rate 17.

[0110] <Resin (D)> The following compounds were used as resin (D) and comparative component (D'). D-1: Polyethylene glycol-modified styrene-maleic acid copolymer (manufactured by BIC Chemie Japan Co., Ltd., product name "DISPERBYK-2010", acid value 20 mg KOH / g). • D-2: Polyethylene glycol-modified styrene-maleic acid copolymer (manufactured by BIC Chemie Japan Co., Ltd., product name "DISPERBYK-190", acid value 10 mg KOH / g). D-3: Styrene maleic acid copolymer (manufactured by BIC Chemie Japan Co., Ltd., product name "BYK194N", acid value 75 mg KOH / g). • D-4: Phosphate ester of polyether-modified styrene-maleic acid copolymer (manufactured by EVONIK, product name "Tegodisperse 655", acid value 190 mgKOH / g). • D-5: Aqueous solution containing a high-molecular-weight polymer and a nonionic surfactant (manufactured by EVONIK, product name "Tegodisperse 760W", acid value 1 mg KOH / g, containing styrene-maleic acid copolymer). • D'-6: Modified polyurethane solution (manufactured by BIC Chemie Japan Co., Ltd., DISPERBYK-184, solids content 52% by mass, acid value 0 mg KOH / g). D'-7: High molecular weight unsaturated carboxylic acid (AFCONA-5266, manufactured by AFCONA, with a solid content of 98% or more and an acid value of 250 mg KOH / g).

[0111] <Hardening agent (E)> The following compound was used as the curing agent (E). • E-1: Isocyanate compound (manufactured by Dainichi Seika Kogyo Co., Ltd., product name "Hydric FC Hardener"). • E-2: Carbodiimide compound (manufactured by Dainichi Seika Kogyo Co., Ltd., product name "AB Hardener"). • E-3: Aziridine compound (manufactured by Dainichi Seika Kogyo Co., Ltd., product name "Hydric RA Hardener").

[0112] <Coloring agent> Pigment: Titanium dioxide (manufactured by Sakai Chemical Industry Co., Ltd., product name "Tightone R-62N").

[0113] <Optional ingredients> • Antifoaming agent: Manufactured by Bic Chemie Japan Co., Ltd., product name "BYK-028". • Leveling agent: EVONIC Corporation, product name "Surfinol 420". Beads: Acrylic beads (manufactured by Aica Kogyo Co., Ltd., product name "Gantz Pearl GM-0401S"). • Thickening agent: MUNZING Co., Ltd., product name "Taffygel PUR 45".

[0114] [Evaluation Method] <Storage stability> 200 mL of water-based ink or water-based medium (water-based liquid composition) was placed in a container (a 300 mL beaker) and left to stand for one week in a 25°C atmosphere. After one week, the container was shaken and the state of the liquid was visually observed. It was evaluated according to the following criteria. ◎: Maintains the same condition as when storage began. ○: Slight separation, sedimentation, or thickening can be observed. △: Clear separation or sedimentation can be observed. ×: Severely separated or settled, or solidified.

[0115] <Two-liquid stability> A coating solution was prepared by mixing an aqueous ink or aqueous medium (aqueous liquid composition) with a curing agent in a container (a 300 mL beaker) at 25°C. Immediately after preparation (day 1), the state of the liquid was visually observed by shaking the container. The coating solution was also used for flexographic printing on day 1 and day 2 (24 hours after preparation). It was evaluated according to the following criteria. ◎: No thickening was observed on day 1, and the mixture remained in the same state as the water-based ink before mixing. It was printable on both day 1 and day 2. ○: A slight increase in viscosity is observed on day 1, but it is still printable. It remains printable on day 2 as well. △: On day 1, a slight increase in viscosity is observed, but printing is still possible. On day 2, the viscosity increases or solidifies, making printing difficult. ×: It thickens or solidifies to the point where printing becomes difficult from the first day.

[0116] <Pot life> A coating solution was prepared by mixing an aqueous ink and a hardener in a container (a 300 mL beaker) at a 25°C atmosphere. The suitability of the solution was determined at elapsed times (1 hour, 2 hours, 4 hours, and 6 hours). Specifically, the coating solution was used for flexographic printing after the predetermined time had elapsed, and its printability was determined. The resulting coating layer was stored at a 25°C atmosphere for 8 hours and then visually inspected. ◎: The coating liquid does not thicken, and the coating layer remains unaffected after storage. ○: Although the coating layer shows increased thickness, it is still printable, and the coating layer remains undamaged after storage. △: Thickening of the coating layer is observed, but it is still printable. Slight unevenness is observed in the coating layer after storage, but it is within an acceptable range. ×: Printing is not possible, or printing is possible, but solid matter exceeding acceptable limits is observed in the coating layer after storage.

[0117] [Evaluation of the coating layer] <Powdering Reduction Test> A laminate consisting of a white coating layer on a plastic substrate was cut into 1 cm wide strips to serve as a test specimen. A JSPS-type friction fastness tester (manufactured by Tester Sangyo Co., Ltd., product name "AB-301") was used to perform a test in which the coating layers of 10 test specimens were rubbed with a single black cotton cloth. The operating conditions were a load of 200g and 10 back-and-forth strokes per test specimen. After the test, the condition of the coating layers on the black cloth and test specimens was visually observed and evaluated according to the following criteria. In this test, if the evaluation is ◎ or ○, it can be concluded that the powdering phenomenon caused by contact between the metal roll of the labeling machine and the coating layer is well reduced, and that the water-based liquid composition has good powdering reduction properties. ◎: There are no white deposits on the black cloth. ○: There is only a small amount of white powder adhering to the black cloth. △: Although there are clear white deposits on the black cloth, there are no areas in the test specimen where the coating layer has been lost. ×: Clear white deposits were observed on the black cloth, and there were areas in the test specimen where the coating layer had been lost.

[0118] <Adhesion Test> A cellophane tape (manufactured by Nichiban Co., Ltd.) with a width of 18 mm was applied to the surface of the coating layer laminated on a plastic substrate and pressed down with a finger. After that, the cellophane tape was quickly peeled off, and the condition of the coating layer remaining on the plastic substrate was visually inspected. The ratio of the area of ​​the peeled coating layer to the adhesive area of ​​the cellophane tape (peeling ratio) was determined, and the adhesion of the coating layer was evaluated according to the following criteria. ◎: The coating layer has not peeled off at all (peeling rate is 0%). ○: The peeling rate is greater than 0% and less than 50%. △: The peeling rate is 50% or more but less than 100%. ×: The peeling rate is 100%.

[0119] <Moisture resistance friction test> Two days after forming the coating layer on the plastic substrate, a test was conducted using the aforementioned JSPS-type friction fastness tester, in which the coating layer was rubbed with a water-soaked black cotton cloth. The operating conditions were: friction area 4 cm² 2 The load was 200g and the test consisted of 100 back-and-forth cycles. After the test, the condition of the coating layer was visually observed, and the ratio of the area of ​​the detached coating layer to the friction area (detachment rate) was determined. The moisture friction resistance of the coating layer was then evaluated according to the following criteria. ◎: The coating layer has not peeled off at all (peeling rate is 0%). ○: The dropout rate is greater than 0% and less than 30%. △: The dropout rate is between 30% and 50%. ×: The dropout rate is 50% or higher.

[0120] <Blocking resistance test> A laminate consisting of a white coating layer on a plastic substrate was subjected to a test in which a film used as the plastic substrate was placed on top of the coating layer and a load of 0.69 MPa was applied using a spring-type blocking tester, and the laminate was left standing for 24 hours in a constant temperature chamber at 40°C without humidity. After the test, the blocking resistance of the coating layer was evaluated according to the following criteria based on the peel resistance when the film was peeled off and the change in the appearance of the coating layer (transfer to the film). ◎: No peeling resistance, and no transfer of the coating layer to the film. ○: There is a very slight resistance to peeling, but there is no transfer of the coating layer to the film. △: Slight peeling resistance is felt, and slight transition of the coating layer to the film can be observed. ×: Strong peeling resistance is felt, and a large portion of the coating layer migrates to the film.

[0121] <Print cleaning test> A coating solution was applied to an anilox roll and left at 20°C for 6 hours to form a coating film. Next, the coating film was cleaned by scrubbing with a melamine sponge moistened with water. The ease of removing the coating film (plate cleaning ability) was evaluated according to the following criteria. ◎: The paint film comes off with just a light rub. ○: If you rub it back and forth 20 times with force, the paint film will come off. △: The paint film will come off if you rub it back and forth 50 times with force. ×: The paint film does not peel off.

[0122] <Manufacturing Example 1: Preparation of Wax> 45 parts of pentaerythritol stearate tetrasubstituted compound (manufactured by Nippon Oil & Fats Co., Ltd., product name "Unistar H-4 76"), an anionic surfactant (manufactured by Clariant, product name "Hostapure SAS93"), and 105 parts of water were mixed, heated to 90°C, and stirred for 10 minutes in a disperser mixer (manufactured by Primix) to obtain a dispersion. The resulting dispersion was emulsified using a homogenizer (manufactured by Sugino Machine Co., Ltd.) at a temperature of 100°C and a pressure of 4.9 MPa. Large-particle-size waxes or small-particle-size waxes were prepared while measuring the average particle size using a Coulter counter type particle size analyzer. The degree of needle penetration of the wax was measured five times for each sample, and the three measurements excluding the maximum and minimum values ​​were averaged to obtain the measurement result for each sample.

[0123] <Examples 1-33, Comparative Examples 1-18> Examples 1-30 and Comparative Examples 1-14, 17, and 18 are examples of aqueous inks prepared from aqueous liquid compositions and pigments. Examples 31 and Comparative Examples 15 and 16 are examples in which an aqueous liquid composition without pigment was prepared as the aqueous medium. Examples 32 and 33 are variations of Example 1 in which the curing agent was changed.

[0124] A pre-dispersion mill base was prepared by mixing an aqueous binder (A), coarse-particle wax (B), fine-particle wax (C), resin (D), defoamer, and, in the case of aqueous ink, pigment, according to the formulation shown in the table. Next, the pre-dispersion mill base was dispersed in a paint shaker apparatus, and then a leveling agent, beads, thickener, and water were added to obtain an aqueous ink or aqueous medium. A mixture of the obtained aqueous ink or aqueous medium and the curing agent shown in the table was used as a coating solution, and a laminate was manufactured by the following method.

[0125] (Manufacturing of laminates) As the plastic substrate, recycled PET film (manufactured by Toyobo Co., Ltd., product name "ReShine", thickness 15 μm) was used. Cell volume 10.0cm 3 / m 2 Using a flexo hand proofer equipped with an anilox roll as an applicator, each example of the coating liquid was applied to one side of a plastic substrate, with a coating amount of 2.0 g / m² after drying. 2 The material was coated (printed) in this manner. Next, it was dried with hot air from a dryer for 1 minute to form a coating layer (coating film) and obtain a laminate (printed material). When the coating solution was water-based ink, a white coating layer was obtained. When the coating solution was water-based medium, a thin white coating layer was obtained because it contained wax, etc.

[0126] (evaluation) The storage stability of the water-based ink or water-based medium was evaluated using the method described above. The two-component stability of the coating solution was evaluated using the method described above. For the coating layer of the laminate, each item shown in the table was evaluated using the method described above. These results are shown in the table. A blank space in the table indicates that the ingredient is not included (amount: 0 parts by mass). NV in the table indicates the non-volatile content (solids) of each ingredient (unit: mass%). In the table, "(B) Solids / Total Solids" refers to the solids content of the large-particle wax (B) relative to the total mass of solids in the aqueous liquid composition (unit: mass%). The same applies to "(C) Solids / Total Solids" and "(D) Solids / Total Solids". In the table, "(B):(C)" indicates the mass ratio of solid content between large particle size wax (B) and small particle size wax (C). In the table, "Urethane:Acrylic Urethane" refers to the mass ratio of water-based urethane resin to water-based acrylic urethane resin.

[0127] [Table 1]

[0128] [Table 2]

[0129] [Table 3]

[0130] [Table 4]

[0131] [Table 5]

[0132] [Table 6]

[0133] [Table 7]

[0134] [Table 8]

[0135] [Table 9]

[0136] [Table 10]

[0137] [Table 11]

[0138] [Table 12]

[0139] [Table 13]

[0140] [Table 14]

[0141] As shown in the table, Examples 1-33 exhibited good storage stability, reduced powdering, adhesion, moisture resistance, blocking resistance, and plate cleaning properties. On the other hand, none of the Comparative Examples 1 to 18 exhibited good storage stability, powder reduction, adhesion, moisture friction resistance, blocking resistance, and plate cleaning performance. In particular, the powder reduction performance in all of the Comparative Examples was inferior to that evaluated in the Examples.

[0142] (Examples of application) In Examples 1 to 33, a single coating layer was formed on a plastic film substrate to create a laminate. However, when a second coating layer was formed on top of the first coating layer in the same manner, the laminate was evaluated in the same way as in Examples 1 to 33, and it was confirmed that it was just as excellent as in Examples 1 to 33. Furthermore, the coating solution for the second coating layer was the same as that used in Examples 1 to 33, and it was confirmed that the results were excellent in both combinations where the coating solution for the first coating layer and the coating solution for the second coating layer were the same, and in combinations where they were different, just as in Examples 1 to 33. [Explanation of Symbols]

[0143] 10 Laminate 11. Plastic film (plastic substrate) 12 Coating layers 20 Laminate 21 Plastic film (plastic substrate) 22 First coating layer 23. Second coating layer

Claims

1. An aqueous liquid composition used for coating plastic substrates, A water-based binder resin (A) is at least one selected from the group consisting of water-based urethane resin, water-based acrylic resin, and water-based acrylic urethane resin, Large particle size wax (B) and small particle size wax (C), The material contains a resin (D) having a polymer chain containing a hydrophobic portion and a hydrophilic portion containing an acid group, The aforementioned large-particle wax (B) has an average particle size of 2.0 μm or more and 10.0 μm or less, and a penetration degree of 5 or more and 30 or less. The aforementioned small-particle wax (C) has an average particle size of 0.1 μm or more and less than 2.0 μm, and a penetration degree of 0.1 or more and less than 15. The acid value of the aforementioned resin (D) is 1 to 245 mg KOH / g. An aqueous liquid composition used for coating plastic substrates, wherein the content of the resin (D) relative to the total mass of the solids in the aqueous liquid composition is 0.1 to 18% by mass.

2. The aqueous liquid composition according to claim 1, wherein the aqueous binder resin (A) comprises both the aqueous urethane resin and the aqueous acrylic urethane resin, and the mass ratio of the solid content of the aqueous urethane resin to the aqueous acrylic urethane resin is 1:0.3 to 1:

20.

3. The aqueous liquid composition according to claim 1, wherein the aqueous binder resin (A) comprises the aqueous acrylic resin, the aqueous acrylic resin comprises both a water-soluble acrylic resin and a water-dispersible acrylic resin, and the mass ratio of the solid content of the water-soluble acrylic resin to the water-dispersible acrylic resin is 1:0.8 to 1:

25.

4. The aqueous liquid composition according to claim 1, wherein the mass ratio of the solid content of the large-particle wax to the small-particle wax is 1:0.1 to 1:

10.

5. The aqueous liquid composition according to claim 1, wherein the resin (D) comprises one or more selected from the group consisting of polyethylene glycol-modified styrene maleic acid copolymer, styrene maleic acid copolymer, phosphate ester of polyether-modified styrene maleic acid copolymer, and styrene maleic acid copolymer having a phosphate ester.

6. The aqueous liquid composition according to claim 1, for use with a curing agent.

7. The aqueous liquid composition according to claim 6, wherein the curing agent comprises one or more selected from the group consisting of carbodiimide-based curing agents, aziridine-based curing agents, and isocyanate-based curing agents.

8. A coating liquid comprising the aqueous liquid composition according to any one of claims 1 to 7.

9. Plastic substrate and A laminate having a coating layer on the plastic substrate comprising the coating liquid described in claim 8.

10. A label obtained using the laminate described in claim 9.

11. The label according to claim 10, which is a label for food and beverages.

12. The label according to claim 10, which is a body wrap label.

Images