Aqueous liquid composition, coating liquid, laminate, and label for use in coating plastic substrates

Abstract

The present invention provides an aqueous liquid composition that is used for coating plastic substrates and has excellent storage stability, powdering reduction properties, adhesion, wet friction resistance, blocking resistance, and plate cleanability. [Solution] An aqueous liquid composition used for coating onto plastic substrates, comprising: an aqueous binder resin (A) which is at least one selected from the group consisting of an aqueous urethane resin, an aqueous acrylic resin, and an aqueous acrylic urethane resin; a large particle size wax (B); a small particle size wax (C); and a resin (D) having a polymer chain containing a hydrophobic portion and a hydrophilic portion containing 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 needle penetration of 5 or more and 30 or less, and 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 needle penetration of 0.1 or more and less than 15, and the content of the solid content of the resin (D) relative to the total mass of the solid content of the aqueous liquid composition is 0.1 to 10 mass%.

Description

[Technical field]

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

[0002] Conventionally, labels have been used on packaging containers for daily necessities such as beverages, foods such as prepared dishes and bento boxes, cosmetics, toiletries, etc., to display various information such as the product name, the manufacturer's logo or other designs, ingredients, etc. Labels are generally produced by printing on a paper or plastic substrate. Commonly used labels using a plastic base material include, for example, labels printed on heat-shrinkable film (shrink film) that shrinks when heat is applied, and wrap-around labels in which a strip of printed plastic film is wrapped around a packaging container and affixed to the container.

[0003] In recent years, there has been an increasing demand for water-based inks, which emit less organic solvent during printing and leave less residual solvent on the substrate compared to organic solvent-based inks. For example, Patent Document 1 discloses an aqueous gravure printing ink composition for paper containers that contains a colorant, an alkali-soluble water-soluble resin, an emulsion-type aqueous resin, a specific wax, and an aqueous medium. Patent Document 2 discloses an aqueous varnish composition that contains two types of wax with different particle sizes and a silicone additive. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-128701 A [Patent Document 2] JP 2023-178658 A Summary of the Invention [Problem to be solved by the invention]

[0005] Since water-based inks have the property of easily penetrating paper, various studies have been conducted on water-based inks for printing on paper substrates. Conventional water-based inks are easily able to adhere to paper, but are poorly able to adhere to plastic substrates. For this reason, it is difficult to use ink compositions for paper to coat plastic substrates. The inventors of the present application have also found that, in the process of attaching a label printed with ink to a packaging container, the metal roll (guide roll) that guides the running film (label) comes into contact with the ink coating, which can easily cause a phenomenon in which powdery foreign matter adheres to the metal roll (also known as "powdering"). An object of the present invention is to provide an aqueous liquid composition which is used for coating plastic substrates and which has excellent storage stability, powdering reduction properties, adhesion, wet friction resistance, blocking resistance and plate cleanability. [Means for solving the problem]

[0006] The present invention has the following aspects. [1] An aqueous liquid composition for use in coating a plastic substrate, comprising: An aqueous binder resin (A) which is at least one selected from the group consisting of an aqueous urethane resin, an aqueous acrylic resin, and an aqueous acrylic urethane resin; A large particle size wax (B) and a small particle size wax (C), (D) a resin having a polymer chain containing a hydrophobic portion and a hydrophilic portion containing an acid group; 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 index 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 index of 0.1 or more and less than 15, The acid value of the resin (D) is 1 to 245 mgKOH / g, An aqueous liquid composition used for coating a plastic substrate, wherein the content of the solid content of the resin (D) is 0.1 to 18 mass % based on the total mass of the solid content of the aqueous liquid composition. [2] The aqueous liquid composition according to [1], wherein the aqueous binder resin (A) contains both the aqueous urethane resin and the aqueous acrylic urethane resin, and the mass ratio of the aqueous urethane resin to the aqueous acrylic urethane resin in terms of the solid content 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, the aqueous acrylic resin contains both a water-soluble acrylic resin and a water-dispersible acrylic resin, and the mass ratio of the water-soluble acrylic resin to the water-dispersible acrylic resin in terms of the solid content 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 contents of the large particle size wax and the small particle size 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 at least one selected from the group consisting of polyethylene glycol-modified styrene-maleic acid copolymers, styrene-maleic acid copolymers, phosphate esters of polyether-modified styrene-maleic acid copolymers, and styrene-maleic acid copolymers having a phosphate ester. [6] The aqueous liquid composition according to any one of [1] to [5], for use together 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-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 [1] to [7] above. [9] A laminate comprising a plastic substrate and a coating layer formed on the plastic substrate, the coating layer being made of the coating liquid according to [8].

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

[11] The label described in

[10] , which is a label for food or beverage products.

[12] The label described in

[10] , which is a waist-wrap label. Effect of the Invention

[0007] According to the present invention, it is possible to provide an aqueous liquid composition which is used for coating plastic substrates and which has excellent storage stability, powdering reduction properties, adhesion, wet friction resistance, blocking resistance, and plate cleanability, as well as a coating liquid, a laminate, and a label which use the same. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view illustrating a schematic example of a laminate of the present invention. [Diagram 2] FIG. 1 is a cross-sectional view illustrating a schematic example of a laminate of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will be described in detail below. The following embodiments are merely examples for explaining the present invention, and are not intended to limit the present invention to these embodiments. The present invention can be implemented in various forms without departing from the spirit of the present invention. The following definitions of terms apply throughout the specification and claims.

[0010] The term "aqueous" in the aqueous liquid composition means that the composition contains an aqueous medium. "Aqueous medium" means a liquid medium that contains water. The term "liquid medium" refers to a volatilizable liquid such as water or an organic solvent. The term "volatile content" refers to volatile components such as water and organic solvents among the components contained in the aqueous liquid composition. Specifically, the heating residue obtained by a measurement method conforming to JIS K 5601-1-2:2008 is defined as the solid content (also called the non-volatile content), and the rest is defined as the volatile content. "(Meth)acrylate" is a general term for "acrylate" and "methacrylate". The symbol "~" indicating a range of numerical values ​​means that the numerical values ​​before and after it are included as the lower limit and upper limit. The lower and upper limits of the numerical ranges disclosed in this specification can be combined in any manner to create new numerical ranges.

[0011] The weight average molecular weight of the aqueous binder resin is a weight average molecular weight converted into a 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: A differential scanning calorimeter is used to measure the glass transition temperature from the intersection point between the baseline and the tangent of the endothermic curve in a curve (DSC curve) obtained by heating 10 mg of the aqueous binder resin from -100°C to 160°C at a temperature 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 gram of solid content of the sample, expressed in milligrams, and is measured in accordance with JIS K 5601-2-1:1999.

[0012] The average particle size of wax is the particle size at 50% cumulative frequency (median size: D50) calculated from the particle size distribution measured by the Coulter counter method. The Coulter counter method is a method in which wax particles dispersed in a solution are passed through a fine hole, and the particle size and particle size distribution of the particles are electrically measured from the change in the electrical signal when the particles pass through the hole. The wax penetration is measured according to the method specified in JIS K-2235-6.3-93. Specifically, the sample is kept at a constant temperature, a 100g load is applied to a specified needle, which is inserted into the sample for 5 seconds, and the depth to which the needle penetrates is measured. The sample temperature is 25°C.

[0013] <Aqueous liquid composition used for coating plastic substrates> The aqueous liquid composition used for coating a plastic substrate in one embodiment of the present invention (hereinafter, also simply referred to as "aqueous liquid composition") contains an aqueous binder resin (A), a large particle size wax (B), a small particle size wax (C), and a resin (D). A colorant can be added to the aqueous liquid composition to produce an aqueous ink. In other words, the aqueous liquid composition means a composition that does not contain a colorant. An aqueous liquid composition that does not contain a colorant can also be used as an aqueous medium or aqueous varnish, which is a liquid for adjusting the hue of an aqueous ink. The aqueous liquid composition of the present embodiment is used for coating a plastic substrate. The type of the 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 an aqueous urethane resin, an aqueous acrylic resin, and an aqueous acrylic urethane resin. In this specification, the term "aqueous urethane resin" is a general term for "water-soluble urethane resin" and "water-dispersible urethane resin (urethane resin emulsion, urethane resin dispersion)." The same applies to "aqueous acrylic resin" and "aqueous acrylic urethane resin." The aqueous binder resin (A) contributes to improving the adhesion between the coating layer and the plastic substrate, and also contributes to the plate washability of the coating liquid.

[0015] [Water-based urethane resin] The aqueous urethane resin may be, for example, a reaction product of a polyisocyanate compound and a polyol compound. The polyisocyanate compound is an organic compound having at least two isocyanate groups in one molecule. The polyol compound is an organic compound having at least two hydroxyl groups in one molecule.

[0016] Examples of the polyisocyanate compound include aliphatic, alicyclic, aromatic, etc. Specific examples of the polyisocyanate compound 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; 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 1,4-bis(isocyanatemethyl)cyclohexane, 1,3-bis(isocyanatemethyl)cyclohexane; m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4- or 2,6-tolylene diisocyanate, 4,4'-toluidine diisocyanate, dianisidine diisocyanate, 4, Examples of the polyisocyanate include aromatic diisocyanates such as 4'-diphenyl ether diisocyanate, polyisocyanate compounds obtained by polymerizing the above diisocyanates to have an allophanate structure, a nurate structure, a biuret structure, or the like, triisocyanates such as 1,3,5-triisocyanate benzene, 2,4,6-triisocyanate toluene, and 1,3,5-triisocyanate hexane, and polyisocyanates such as 4,4'-diphenyl dimethyl methane-2,2'-5,5'-tetraisocyanate, etc. These polyisocyanate compounds may be used alone or in combination of two or more.

[0017] Examples of the polyol compound 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 an initiator; 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 polyester polyols obtained by dehydration condensation of 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 with the corresponding acid anhydrides or dimer acids; polyolefin polyols, such as polyethylene polyols and polypropylene polyols; polyether ester polyols obtained by reacting the above dibasic acids or their dialkyl esters with the above polyether polyols; and polycarbonate polyols obtained by reacting the above glycols with methyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, or the like. These polyol compounds may be used alone 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 from the viewpoint of achieving a particularly excellent balance between the blocking resistance of the coating layer and the adhesion to the plastic substrate, further preferably 20,000 to 80,000. When the weight average molecular weight of the aqueous urethane resin is equal to or more than the lower limit, the blocking resistance of the coating layer is improved, and when it is equal to or less than 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 from the viewpoint of achieving a particularly excellent balance between the blocking resistance of the coating layer and the adhesion to the plastic substrate, further preferably 40 to 100° C. When the glass transition temperature of the aqueous urethane resin is equal to or higher than the above lower limit, the blocking resistance of the coating layer is improved, and when it is equal to or lower than the above 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 mgKOH / g, and more preferably 1 to 50 mgKOH / g, from the viewpoint of particularly excellent balance of adhesion of the coating layer to the plastic substrate, crosslinking density with the curing agent, and coating liquid stability when the curing agent is added. When the aqueous urethane resin has an acid value, good water solubility is obtained. In addition, when the curing agent (E) described later is used in combination, a robust coating layer is obtained by crosslinking with the curing agent.

[0021] The aqueous urethane resin can be obtained, for example, by reacting a polyisocyanate compound with a polyol compound by a known method. Alternatively, a silanol group may be introduced by reacting a reaction product of a polyisocyanate compound and a polyol compound with a hydrolyzable silicon group-containing compound. The hydrolyzable silicon group-containing compound is a compound that contains a hydrolyzable silicon group, and preferably contains an active hydrogen group in addition to the hydrolyzable silicon group. The hydrolyzable silicon group includes a group in which a hydrolyzable group generated when hydrolyzed in the presence or absence of a silanol condensation catalyst is bonded to a silicon atom.The hydrolyzable group includes, for example, a hydrogen atom, a halogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an aminooxy group, a mercapto group, an alkenyloxy group, etc.Usually, one to three hydrolyzable groups are bonded to one silicon atom. Examples of the active hydrogen group include an amino group, a hydroxyl group, and a mercapto group.

[0022] As the aqueous urethane resin, commercially available products may be used, such as "HYDRAN WLS-210" manufactured by DIC Corporation, "NEOSTICKER 400" and "NEOSTICKER 200" manufactured by NICCA Chemical Co., Ltd., "SUPERFLEX 500M" manufactured by Daiichi Kogyo Seiyaku Co., Ltd., and "TAKELACK W-5661", "TAKELACK WS-5000", "TAKELACK W-6010", "TAKELACK WS-5100", "TAKELACK WS-4000", and "TAKELACK W-635" manufactured by Mitsui Chemicals, Inc. The aqueous urethane resin may be used alone or in combination of two or more kinds.

[0023] [Water-based acrylic urethane resin] Examples of the aqueous acrylic urethane resin include a reaction product of a polyisocyanate compound, a polyol compound, and a hydroxy group-containing (meth)acrylate, or a reaction product of a polyisocyanate compound and a hydroxy group-containing (meth)acrylate. Examples of the polyisocyanate compound include the polyisocyanate compounds exemplified above in the explanation of the aqueous urethane resin. Examples of the polyol compound include the polyol compounds exemplified above in the explanation of the aqueous urethane resin.

[0024] Examples of the hydroxy group-containing (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. Furthermore, as the aqueous acrylic urethane resin, for example, a core-shell type resin having an acrylic resin in the core portion and a urethane resin in the shell portion 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 from the viewpoint of achieving a particularly excellent balance between the solvent resistance, water resistance, blocking resistance, and adhesion to the plastic substrate of the coating layer, is even more preferably 10,000 to 80,000. When the weight-average molecular weight of the aqueous acrylic urethane resin is equal to or greater than the lower limit, the solvent resistance and blocking resistance of the coating layer are improved, and when it is equal to or less than 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 from the viewpoint of achieving a particularly excellent balance between the blocking resistance of the coating layer and the adhesion to the plastic substrate, further preferably −20 to 90° C. When the glass transition temperature of the aqueous acrylic urethane resin is equal to or higher than the above lower limit, the blocking resistance of the coating layer is improved, and when the glass transition temperature is equal to or lower than the above 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 mgKOH / g, and more preferably 1 to 60 mgKOH / g, from the viewpoint of particularly excellent balance between adhesion of the coating layer to the plastic substrate and stability of the coating liquid when a curing agent is added. When the aqueous acrylic urethane resin has an acid value, good water solubility is obtained. In addition, when a curing agent (E) described later is used in combination, a robust coating layer is obtained by crosslinking with the curing agent.

[0028] The aqueous acrylic urethane resin can be obtained by reacting a polyisocyanate compound, a polyol compound, and a hydroxyl group-containing (meth)acrylate, or a polyisocyanate compound and a hydroxyl group-containing (meth)acrylate, by a known method.

[0029] The aqueous acrylic urethane resin may be a commercially available product, such as "WEM-200U", "WEM-505C", or "WEM-3000" manufactured by Taisei Fine Chemical Co., Ltd., or "NeoPack E-315" manufactured by Covestro Coating Resins. The aqueous acrylic urethane resin may be used alone or in combination of two or more kinds.

[0030] [Water-based acrylic resin] "Water-based acrylic resin" is a general term for "water-soluble acrylic resin" and "water-dispersible acrylic resin (acrylic resin emulsion, acrylic resin dispersion)." The acrylic resin is a polymer or copolymer containing a (meth)acrylate unit. For example, it may be a homopolymer of (meth)acrylate, a copolymer of two or more kinds of (meth)acrylate, or a copolymer of (meth)acrylate and a monomer other than (meth)acrylate. The ratio of the (meth)acrylate unit to the total mass of all monomer units constituting the acrylic resin is preferably 10 to 100% by mass, 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 alone 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; cyanide vinyl 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 alone or in combination of two or more.

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

[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 achieving a particularly excellent balance of pigment dispersibility, fluidity and resolubility of the coating liquid, blocking resistance of the coating layer, and adhesion to plastic substrates.

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

[0036] The water-soluble acrylic resin can be obtained by polymerizing a monomer component containing a (meth)acrylate and, if necessary, a monomer other than the (meth)acrylate. The polymerization method is not particularly limited, but examples thereof include a method in which a monomer component is polymerized in the presence of a known radical polymerization initiator by a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, or the like. The water-soluble acrylic resin may be of the self-crosslinking type.

[0037] As the water-soluble acrylic resin, a commercially available product may be used. Examples of commercially available products include those manufactured by Seiko PMC Corporation under the product names "Hi-Loss-X PL-1231", "Hi-Loss-X BL-2300", "Hi-Loss-X NL-1253", "Hi-Loss-X M-30", "Hi-Loss-X YL-1098", "Hi-Loss-X QL-1358", "Hi-Loss-X GL-2439", "Hi-Loss-X VL-1147", and "Hi-Loss-X NL-1189"; and those manufactured by BASF Japan Ltd. under the product names "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". The water-soluble acrylic resin may be used alone or in combination of two or more kinds.

[0038] [Water-dispersible acrylic resin] As the water-dispersible acrylic resin, for example, a core-shell type resin having an 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 mgKOH / g, more preferably 5 to 150 mgKOH / g, and even more preferably 10 to 100 mgKOH / g from the viewpoint of achieving a particularly excellent balance between the adhesion of the coating layer to the plastic substrate and the stability of the coating liquid 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 from the viewpoint of obtaining a particularly excellent balance of the solvent resistance, water resistance, blocking resistance, and adhesion to plastic substrates of the coating layer, it is further preferably 20,000 to 390,000.

[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., particularly preferably 0 to 70° C., and most preferably 5 to 60° C. from the viewpoint of achieving a particularly excellent balance between the blocking resistance of the coating layer and the adhesion to the plastic substrate.

[0042] The water-dispersible acrylic resin can be produced by a known method using, for example, a polymer emulsifier method, a two-stage emulsion polymerization method, etc. For example, it can be produced by a method of synthesizing a core-shell type water-dispersible acrylic resin by a polymer emulsifier method.

[0043] Commercially available water-dispersible acrylic resins can also be used. Commercially available water-dispersible acrylic resins include, for example, the product names "Hi-Loss-X QE-1042", "Hi-Loss-X M-141", "Hi-Loss-X TE-1048", "Hi-Loss-X KE-1062", "Hi-Loss-X X-436", "Hi-Loss-X KE-1060", "Hi-Loss-X HE-1335", "Hi-Loss-X RE-1075", "Hi-Loss-X PE-1304", "Hi-Loss-X KE-2536", "Hi-Loss-X J-140A", "Hi-Loss-X TE-1102", "Hi-Loss-X RE-218", "Hi-Loss-X NE-2009", "Hi-Loss-X JE-1056", "Hi-Loss-X KE-1148", "Hi-Loss-X ME-2039", "Hi-Loss-X UE-1051", and "Hi-Loss-X PE-1126", BASF Japan Ltd. product names: "Jonkryl PDX-7616A", "Jonkryl PDX-7356", "Jonkryl PDX-7777", "Jonkryl PDX-7357", "Jonkryl PDX-7182", "Jonkryl PDX-7326", "Jonkryl PDX-7732", "Jonkryl PDX-7741", "Jonkryl PDX-7787", "Jonkryl PDX-7734", "Jonkryl PDX-7615", "Jonkryl PDX-77 75", "Johncryl PDX-7692", "Johncryl PDX-7630A", "Johncryl PDX-7158", "Johncryl 352D", "Johncryl PDX-7199", "Johncryl PDX-7358", "Johncryl PDX-7667", "Johncryl PDX-7700", "Johncryl PDX-7696", "Johncryl PDX-7780", "Johncryl PDX-7177", "Johncryl PDX-7430", and Aica Kogyo Co., Ltd. product names "Ultrasol A-25", "Ultrasol A-35", "Ultrasol A-40", "Ultrasol A-50", "Ultrasol C-63", "Ultrasol C-70", "Ultrasol D-32", "Ultrasol D-40", "Ultrasol GP-300", "Ultrasol UL-1097", etc. The water-dispersible acrylic resin may be used alone or in combination of two or more kinds.

[0044] <Wax> As the wax to be contained in the aqueous liquid composition, a large particle size wax (B) and a small particle size wax (C) which are different from each other in average particle size and penetration are used in combination. The large particle size wax (B) and the small particle size wax (C) may be the same or different in material, but are preferably the same in terms of powdering reduction and compatibility.

[0045] Examples of the materials of the large particle size wax (B) and the small particle size wax (C) include animal and vegetable waxes such as beeswax, lanolin wax, spermaceti, candelilla wax, carnauba wax, rice wax, Japan wax, and jojoba oil; mineral and petroleum waxes such as montan 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 montan wax derivatives, paraffin wax derivatives, and microcrystalline wax derivatives; hydrogenated waxes such as hydrogenated castor oil and hydrogenated castor oil derivatives; polytetrafluoroethylene wax (PTFE); carboxylic acid esters or partial esters of polyhydric alcohols obtained by reacting polyhydric alcohols (glycerin, pentaerythritol, etc.) with long-chain fatty acids; and the like. The large particle size wax (B) and the small particle size wax (C) may be produced by a known method, may be a natural product, or may be a commercially available product. The large particle size wax (B) or the small particle size wax (C) may be obtained by adjusting the particle size of a commercially available wax compound.

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

[0047] Commercially available polyethylene waxes include those manufactured by Mitsui Chemicals under the product names "CHEMIPERL W100", "CHEMIPERL W200", "CHEMIPERL W300", "CHEMIPERL W308", "CHEMIPERL W400", "CHEMIPERL W401", "CHEMIPERL W500", "CHEMIPERL W640", "CHEMIPERL W700", and "CHEMIPERL W800"; and those manufactured by BYK under the product names "CERAFLOUR925", "CERAFLOUR925N", "CERAFLOUR927N", and "CERAFLOUR929". , "CERAFLOUR929N", "CERAFLOUR950", "CERAFLOUR960", "CERAFLOUR961", "CERAFLOUR988", "CERAFLOUR991", "CERAFLOUR1000", "AQUACER531", "AQUACER537", "AQUACER552", "AQUACER840", "AQUACER1547", "AQUAMAT208"; and the product name "John Kryllwax 4" made by BASF Japan.

[0048] <Large particle size wax (B)> 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 index of 5 or more and 30 or less. The average particle size of the large particle size 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. When the average particle size of the large particle size wax (B) is equal to or more than the lower limit of the above range, the powdering reduction property is improved. In addition, the wet friction resistance is improved. When it is equal to or less than the upper limit of the above range, the powdering reduction property and the wet friction resistance are improved. In addition, the blocking resistance is improved. When the average particle size of the large particle size wax (B) is less than 2.0 μm, the powdering reduction property and the wet friction resistance are inferior, and when it exceeds 10.0 μm, the powdering reduction property, the blocking resistance and the wet friction resistance are inferior. The penetration degree of the large particle size wax (B) is preferably 5 or more and less than 7 from the viewpoint of wet friction resistance. From the viewpoint of reducing powdering and improving adhesion, it is more preferably 7 or more and 28 or less. When the penetration degree of the large particle size wax (B) is equal to or more than the lower limit of the above range, the reduction in powdering is improved. In addition, the wet friction resistance is improved. When it is equal to or less than the upper limit of the above range, the reduction in powdering is improved. In addition, the blocking resistance is improved. When the penetration degree of the large particle size wax (B) is less than 5, the reduction in powdering and the wet friction resistance are poor, and when it exceeds 30, the reduction in powdering and the blocking resistance are poor.

[0049] <Small particle size wax (C)> 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 index of 0.1 or more and less than 15. The average particle size of the small particle size 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 powdering reduction and adhesion, and preferably 1.2 μm or more and less than 2.0 μm from the viewpoint of wet friction resistance. When the average particle size of the small particle size wax (C) is equal to or more than the lower limit of the above range, the powdering reduction and wet friction resistance are improved. When it is equal to or less than the upper limit of the above range, the powdering reduction is improved. In addition, the wet friction resistance is improved. When the small particle size wax (C) has an average particle size of less than 0.1 μm, the powdering reduction and wet friction resistance are poor, and when it is 2.0 μm or more, the powdering reduction and wet friction resistance are poor. The penetration of the small particle size wax (C) is preferably 0.1 or more and less than 12 from the viewpoint of wet 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. When the penetration of the small particle size wax (C) is equal to or more than the lower limit of the above range, the powdering reduction property is improved. In addition, blocking resistance is improved. When it is equal to or less than the upper limit of the above range, the powdering reduction property and wet friction resistance are improved. When the penetration of the small particle size wax (C) is less than 0.1, blocking resistance and powdering reduction property are inferior, and when it is 15 or more, the powdering reduction property and wet friction resistance are inferior.

[0050] <Resin (D)> The resin (D) is an additive (dusting reduction assistant) that contributes to the effect of reducing the powdering phenomenon (dusting reduction property) when used together with the large particle size wax (B) and the small particle size wax (C). The powdering phenomenon is a phenomenon in which a powdery foreign matter adheres to a metal roll (guide roll) that guides a long laminate, which has a coating layer on a plastic film (plastic substrate), during a label attachment process in which the long laminate is cut and attached to a packaging container when the coating layer comes into contact with the metal roll. This powdery foreign matter is thought to originate from the solid content in the coating layer. When powdering occurs, it becomes necessary to remove the foreign matter adhering to the metal roll. In addition, the foreign matter on the metal roll may transfer to and adhere to the laminate, in which case the foreign matter on the laminate must also be removed. Therefore, by reducing the powdering phenomenon, the removal work is no longer necessary, and the productivity in the process of attaching labels to packaging containers can be improved.

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

[0052] Examples of the hydrophobic portion present in the polymer chain include structural units derived from hydrophobic monomers, polyolefin chains, and the like. The hydrophobic monomer may be an ethylenically unsaturated monomer having an aromatic ring, such as styrene, α-methylstyrene, vinyltoluene, or a derivative thereof. The polyolefin chain includes a polyethylene chain and a polypropylene chain.

[0053] The hydrophilic portion of the resin (D) contains acid groups. The hydrophilic portion present in the polymer chain may be a structural unit derived from an acid group-containing ethylenically unsaturated monomer. Specific examples of the acid group-containing ethylenically unsaturated monomer include maleic anhydride, maleic acid, maleic acid monoester, and derivatives thereof. The hydrophilic moieties attached to the polymer chain include phosphate esters.

[0054] Examples of the 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 above copolymers or resins used as the resin (D) also have a surfactant function and a dispersing function. The resin (D) may be used alone or in combination of two or more kinds.

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

[0056] The acid value of resin (D) is 1 to 245 mgKOH / g, and from the viewpoints of powdering reduction, wet abrasion resistance, and plate cleanability, it is more preferably 1 to 220 mgKOH / g. If the acid value of resin (D) is less than 1 mgKOH / g, the powdering reduction, adhesion, wet abrasion resistance, and plate cleanability are poor, and if it exceeds 245 mgKOH / g, the powdering reduction, wet abrasion resistance, blocking resistance, and plate cleanability are poor.

[0057] The molecular weight of resin (D) is preferably 3000 to 50,000, and from the viewpoint of improving the stability of the two-component composition, more preferably 5000 to 30,000. When the molecular weight of resin (D) is equal to or more than the lower limit of the above range, blocking resistance is improved, and when it is equal to or less than the upper limit, adhesion is improved.

[0058] The resin (D) may be a synthetic product produced by a known method, or a commercially available product. Examples of commercially available products include BYK products under the names "DISPERBYK-190", "DISPERBYK-194N" and "DISPERBYK-2010" and EVONIC products under the names "Tego Disperse 655" and "Tego Disperse 760W".

[0059] <Aqueous medium> The aqueous liquid composition of the present embodiment contains an aqueous medium. Examples of the aqueous medium 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, and examples thereof 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 alone or in combination of two or more. The content of water relative to the total mass of the aqueous medium is preferably from 60 to 100 mass %, more preferably from 70 to 100 mass %, and even more preferably from 80 to 100 mass %.

[0060] <Optional ingredients> The aqueous liquid composition may contain optional components other than the above components, if necessary. As optional components, additives known in the art for coating liquids for plastic substrates can be used. Examples of additives include thickeners, antisettling agents, UV absorbers, antioxidants, leveling agents, viscoelasticity regulators, surface tension regulators, rheology regulators, light stabilizers, antifoaming agents, lubricants, dispersants, stabilizers, pH regulators, fillers, antifungal agents, antistatic agents, metal fine particles, magnetic powders, etc. The optional components may be used alone or in combination of two or more.

[0061] <Composition of the aqueous liquid composition> [Water-based binder resin (A)] The content of the solid content of the aqueous binder resin (A) is preferably 40 to 90 mass%, more preferably 45 to 88 mass%, based on the total mass of the solid content of the aqueous liquid composition (also referred to as the total solid content). When the solid content of the aqueous binder resin (A) in the aqueous liquid composition is equal to or more than the lower limit of the above range, the drying property of the coating film during coating is improved. In addition, the adhesion between the coating layer and the plastic substrate is excellent. When the solid content is equal to or less than the upper limit of the above range, the fluidity of the aqueous liquid composition is improved.

[0062] From the viewpoints of wet friction resistance and blocking resistance, it is preferable to use both an aqueous urethane resin and an aqueous acrylic urethane resin as the aqueous binder resin (A). When the aqueous binder resin (A) contains both an aqueous urethane resin and an aqueous acrylic urethane resin, the aqueous urethane resin:aqueous acrylic urethane resin, which represents the mass ratio of the solid contents of the aqueous urethane resin and the aqueous acrylic urethane resin, is preferably 1:0.3 to 1:20, and more preferably 1:0.3 to 1:5 in terms of wet friction resistance and blocking resistance. From the viewpoints of powdering reduction, wet friction resistance, and blocking resistance, 1:0.3 to 1:1.5 is particularly preferred. When the mass ratio of the aqueous acrylic urethane resin to the aqueous urethane resin is equal to or greater than the lower limit of the above range, wet friction resistance and blocking resistance are improved, and when it is equal to or less than the upper limit, two-liquid 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 water-soluble acrylic resin to the water-dispersible acrylic resin, which represents the solid content of the water-soluble acrylic resin and the water-dispersible acrylic resin, is preferably 1:0.8 to 1:25 from the viewpoint of wet friction resistance and blocking resistance. When the mass ratio of the water-dispersible acrylic resin to the water-soluble acrylic resin is equal to or more than the lower limit of the above range, the wet friction resistance and blocking resistance are improved, and when it is equal to or less than the upper limit, the wet friction resistance and blocking resistance are improved.

[0064] The aqueous liquid composition may contain a known aqueous binder resin other than the aqueous urethane resin, the aqueous acrylic resin, and the aqueous acrylic urethane resin, as long as the effect of the present invention is not impaired. For example, the total amount of the solid content of the aqueous urethane resin, the aqueous acrylic resin, and the aqueous acrylic urethane resin may be, for example, 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, or 90 mass% or more, or may be 100 mass%, based on the total mass of the solid content of the aqueous binder resin (A). When the aqueous binder resin (A) contains both an aqueous urethane resin and an aqueous acrylic urethane resin, the total amount of the solid contents of the aqueous urethane resin and the aqueous acrylic urethane resin relative to the total mass of the solid contents of the aqueous binder resin (A) may be, for example, 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, or 90 mass% or more, or may be 100 mass%. When the aqueous binder resin (A) contains both a water-soluble acrylic resin and a water-dispersible acrylic resin, the total amount of the solid contents of the water-soluble acrylic resin and the water-dispersible acrylic resin relative to the total mass of the solid contents of the aqueous binder resin (A) may be, for example, 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, or 90 mass% or more, or may be 100 mass%.

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

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

[0067] (ratio of large particle size wax to small particle size wax) The mass ratio of the large particle wax to the small particle wax, which represents the solid content mass ratio of the large particle wax to the small particle wax contained in the aqueous liquid composition, is preferably 1:0.1 to 1:10, more preferably 1:1 to 1:3 from the viewpoint of improving adhesion, and even more preferably from 1:3 to 1:8 from the viewpoint of improving blocking resistance. When the mass ratio of the small particle wax to the large particle wax is 0.1 or more of the above range of 1:0.1, the two-liquid stability, adhesion, and plate cleaning properties are improved. When the mass ratio of the small particle wax to the large particle wax is 10 or less of the above range of 1:10, the powdering reduction, adhesion, wet friction resistance, and blocking resistance are improved.

[0068] [Resin (D)] The content of the solid content of the resin (D) relative to the total mass of the solid content of the aqueous liquid composition (total solid content) is 0.1 to 18 mass%, preferably 1 to 10 mass%, and more preferably 3 to 7 mass% from the viewpoint of powdering reduction and adhesion improvement. When the solid content of the resin (D) in the total solid content of the pigment-free aqueous liquid composition is equal to or more than the lower limit of the above range, the two-component stability and powdering reduction are improved. In addition, the plate washability is improved. When it is equal to or less than the upper limit of the above range, the powdering reduction is improved. In addition, the adhesion, wet friction resistance, and blocking resistance between the coating layer and the plastic substrate are improved. When the solid content of the resin (D) in the total solid content of the aqueous liquid composition is less than 0.1 mass%, the two-component stability, plate washability, and powdering reduction are inferior, and when it exceeds 10 mass%, the powdering reduction, adhesion, wet friction resistance, and blocking resistance are inferior.

[0069] [Total solids] The total solid content of the aqueous liquid composition is preferably 10% by mass or more and 60% by mass or less, more preferably 15% by mass or more and 50% by mass or less, based on the total mass of the aqueous liquid composition. When the total solid content of the aqueous liquid composition is equal to or more than the lower limit of the above range, the drying property of the coating film during application is improved. When the total solid content is equal to or less than the upper limit of the above range, the fluidity of the aqueous liquid composition is improved.

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

[0071] <Hardening agent (E)> The aqueous liquid composition of the present embodiment may be used together with a curing agent (E). For example, the aqueous liquid composition and the curing agent (E) may be mixed to prepare a coating liquid, and the obtained coating liquid may be applied to a plastic substrate. Use of the curing agent (E) improves the coating film properties such as water resistance and abrasion resistance of the coating layer, as well as adhesion to plastic substrates.

[0072] As the curing agent (E), those known 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, aziridine-based curing agents, etc. Among these, from the viewpoint of two-liquid stability, isocyanate-based curing agents, carbodiimide-based curing agents, and aziridine-based curing agents are preferred. These curing agents (E) may be used alone or in combination of two or more. Among them, isocyanate-based curing agents are particularly excellent in pot life, and aziridine-based curing agents are particularly excellent in wet friction resistance and dry friction resistance.

[0073] Specific examples of the isocyanate-based curing agent include the polyisocyanate compounds exemplified above in the explanation of the aqueous acrylic urethane resin. Commercially available isocyanate-based curing agents include those manufactured by Mitsui Chemicals, Inc. under the product names "Takenate WD-720," "Takenate WD-725," "Takenate WD-726," "Takenate WD-730," "Takenate WD-220," "Takenate XWD-HS7," and "Takenate XWD-HS30"; those manufactured by Nippon Polyurethane Industry Co., Ltd. under the product names "Aquanate 100," "Aquanate 110," "Aquanate 200," and "Aquanate 210"; those manufactured by Asahi Kasei Corporation under the 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 those manufactured by Bayer MaterialScience under the product names "Bayhydur 3100", "Bayhydur 302", "Bayhydur 304", "Bayhydur 305", "Bayhydur XP2451 / 1", "Bayhydur XP2487 / 1", "Bayhydur XP2547", "Bayhydur XP2655", "Bayhydur XP2700"; BASF products under the names "Basonat HW100", "Basonat HA100", and "Basonat HW1180PC", and Dainichiseika Color & Chemicals Mfg. Co., Ltd. product under the name "Hydrick FC Hardener". The isocyanate-based curing agent may be used alone or in combination of two or more kinds.

[0074] Specific examples of blocked isocyanate curing agents include those blocked with a blocking agent of an isocyanate curing agent (e.g., an alcohol-based compound, a phenol-based compound, an oxime-based compound, a lactam-based compound, a pyrazole-based compound, an active methylene compound, etc.). These blocked isocyanate curing agents may be used alone or in combination of two or more.

[0075] A carbodiimide-based curing agent is a compound containing two or more carbodiimide groups in one 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 manufactured by Nisshinbo Chemical Inc. and the "AB Hardener" manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. These carbodiimide-based curing agents may be used alone or in combination of two or more kinds.

[0076] An oxazoline-based curing agent is a compound containing two or more oxazoline groups in one molecule. Specific examples of oxazoline-based curing agents include polyvalent oxazolines such as 2,2'-bis-(2-oxazoline), 2,2'-methylene-bis-(2-oxazoline), and 2,2'-(1,4-phenylene)-bis(2-oxazoline), and 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. The oxazoline-group-containing monomers may be used alone or in combination of two or more kinds. In addition, the oxazoline-group-containing monomer may be a copolymer of another monomer copolymerizable with the monomer. Commercially available oxazoline-based curing agents include the "Epocross" series manufactured by Nippon Shokubai Co., Ltd. These oxazoline-based curing agents may be used alone or in combination of two or more kinds.

[0077] An epoxy-based curing agent is a compound containing two or more epoxy groups in one molecule. Specific examples of epoxy-based curing agents include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, triglycidyl aminophenol, biphenyl diglycidyl ether, triglycidyl isocyanurate, polyglycidyl (meth)acrylate, and copolymers of glycidyl (meth)acrylate and vinyl monomers copolymerizable therewith. Commercially available epoxy-based curing agents include the "jER" series manufactured by Mitsubishi Chemical Corporation and the "Denacol EX" series manufactured by Nagase ChemteX Corporation. These epoxy-based curing agents may be used alone or in combination of two or more.

[0078] Aziridine-based hardeners are compounds that contain two or more aziridine groups in one molecule. Specific examples of aziridine-based hardeners include 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] and 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane. Commercially available aziridine-based hardeners include the "ChemiTite" series manufactured by Nippon Shokubai Co., Ltd. and "Hydrick RA Hardener" manufactured by Dainichiseika Color & Chemicals Co., Ltd. These aziridine-based curing agents may be used alone or in combination of two or more kinds.

[0079] When the aqueous liquid composition is used in combination with the curing agent (E), if the amount of the curing agent (E) used is too small, the curing reaction may not proceed sufficiently, whereas if the amount is too large, the water resistance of the coating layer may decrease. In order to prevent these inconveniences from occurring, it is preferable to mix the two 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, relative to 100 parts by mass of the total mass of the aqueous liquid composition. Furthermore, by setting the ratio of the curing agent within the above range, an aqueous liquid composition excellent in the fluidity of the coating liquid during coating and in the pot life of the coating liquid after mixing with the curing agent can be obtained.

[0080] <Water-based ink> The aqueous ink of the present embodiment contains the aqueous liquid composition of the present embodiment and a colorant. If necessary, the aqueous ink may further contain additives for aqueous inks in addition to the optional components listed above. Examples of colorants include conventionally known organic pigments and inorganic pigments used in general inks, paints, and recording materials. Examples of organic pigments include organic pigments such as phthalocyanine pigments (phthalocyanine blue, phthalocyanine green, etc.), azo pigments (monoazo, condensed azo, etc.), threne pigments (anthraquinone, perinone, perylene, thioindigo, etc.), quinacridone pigments, dioxazine pigments, isoindolinone pigments, pyrrolopyrrole pigments, aniline black, and organic fluorescent pigments; and inorganic pigments such as natural products (clay, etc.), ferrocyanides (princess blue, etc.), sulfides (zinc sulfide, etc.), sulfates, oxides (titanium oxide, chromium oxide, zinc oxide, iron oxide, etc.), hydroxides (aluminum hydroxide, etc.), silicates (ultramarine blue, etc.), carbonates, carbon (carbon black, graphite, etc.), metal powders (aluminum powder, bronze powder, zinc powder, etc.), and calcined pigments.

[0081] Additives for water-based inks include dispersants, surface conditioners, and defoamers.

[0082] The content of the colorant is preferably 1 to 60% by mass based on the total mass of the water-based ink. When an organic pigment is used as the colorant, the content of the organic pigment is preferably 1 to 35% by mass relative to the total mass of the water-based ink. When an inorganic pigment such as titanium oxide or barium sulfate is used as a colorant, the content of the inorganic pigment is preferably 10 to 60 mass % based on the total mass of the water-based ink.

[0083] When the water-based ink and the curing agent (E) are used in combination, it is preferable to mix the two 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 comprises the aqueous liquid composition of this embodiment. The aqueous medium is used as a hue adjusting liquid that does not contain a colorant by mixing with the aqueous ink. However, the use of the aqueous medium is not limited to color matching, and it is also preferable to use it as an aqueous varnish. In the combination of the aqueous medium and the aqueous ink to be mixed, the combination of the aqueous medium of this embodiment and the aqueous ink of this embodiment is preferable, and it is more preferable that the composition of the aqueous liquid composition in the aqueous ink is the same as the composition of the aqueous medium. When the mixture of the water-based ink and the water-based medium is used in combination with the curing agent (E), the two are mixed 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 mixture of the water-based ink and the water-based medium. When using the aqueous varnish and the curing agent (E) in combination, it is preferable to mix the two 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 aqueous varnish.

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

[0086] <Laminate> An example of a laminate having a plastic substrate according to one embodiment of the present invention and a coating layer made of a coating liquid is shown in Figures 1 and 2. In this specification, the term "coating layer made of a coating liquid" refers to a layer made of components other than volatile components in the coating liquid. For ease of explanation, the dimensional ratios in Figures 1 and 2 are different from the actual ones. The laminate 10 in Figure 1 comprises a plastic film 11 which is a plastic substrate, and a coating layer 12 provided on one side 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 side of the plastic film 21, and a second coating layer 23 provided on the first coating layer. In the laminates 10 and 20, the coating layer 12 or the second coating layer 23 may be the outermost layer on the viewing side, or the plastic films 11 and 21 may be the outermost layer 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 on the outer side of the coating layer 12 and the second coating layer 23, that is, the first coating layer 12 and the second coating layer 23 are attached on the inner side (the side in contact with the packaging container). In addition, other coating layers may be provided on the surfaces of the plastic films 11 and 21 by coating a composition containing a matting agent such as a varnish composition or an extender pigment. Here, the surface of the plastic film 11 means the surface opposite to the surface of the plastic film 11 on which the coating layer 12 is provided. The surface of the plastic film 21 means the surface opposite to the surface of the plastic film 21 on which the first coating layer 22 is provided. In addition, the surface of the plastic film 11 on which the coating layer 12 is provided is referred to as the back surface of the plastic film 11, and the surface of the plastic film 21 on which the first coating layer 22 is provided is referred to as the back surface of the plastic film 21.

[0088] <Plastic substrate> The type of the plastic films 11, 21 that are the plastic substrates can be appropriately selected depending on the application of the laminates 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); celluloses 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, 20 are used as heat-shrinkable labels (shrink labels), the plastic films 11, 21 are preferably uniaxially shrinkable polystyrene films, uniaxially shrinkable PET films, uniaxially shrinkable polyolefin films, or uniaxially shrinkable polyvinyl chloride films. When the laminates 10, 20 are used as a drum-wrapped label (roll label), the plastic films 11, 21 can be either oriented or unoriented plastic films, such as biaxially oriented PP film (OPP film) and unoriented PP film.

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

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

[0092] The thickness of the plastic films 11, 21 is preferably from 5 to 100 μm, more preferably from 12 to 60 μm, and even more preferably from 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 the present embodiment described above will also be referred to as the "present coating layer." The coating layer 12 of the laminate 10 is a main coating layer. At least the second coating layer 23 of the laminate 20 is a 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 main coating layer is preferably from 0.2 to 3.0 μm, more preferably from 0.3 to 2.0 μm, and even more preferably from 0.3 to 1.5 μm.

[0094] (First coating layer) The first coating layer 22 may be a main coating layer formed using a coating liquid containing the aqueous liquid composition of the present embodiment described above, or 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 main coating layers. In the laminate 20, for example, the first coating layer 22 is a coating layer (hereinafter also referred to as a "color coating layer") formed using an ink composition in order to impart design, functionality, etc. to the laminate 20, 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 imparting hiding properties. The first coating layer 22 may have a single-layer structure or a multi-layer structure. 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 of manufacturing laminate> The method for producing a laminate includes a 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 of the laminate 10 in Fig. 1 includes a step of forming a coating layer 12 on one surface of a plastic film 11 using a coating liquid. The manufacturing method of the laminate 20 in Fig. 2 includes a step (1) of forming a first coating layer 22 on one surface of a plastic film 21 using a first coating liquid, and a step (2) of forming a second coating layer 23 on the first coating layer 22 using a second coating liquid.

[0096] 1, for example, a coating liquid is applied onto one surface of a plastic film 11 and dried to form a coating layer 12. After a coating liquid is applied onto one surface of a plastic film 11 and dried to form a coating layer 12, the same coating liquid may be further applied (recoated).

[0097] The method for applying the coating liquid is not particularly limited, and any known coating method can be used, 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, curtain coating method, etc. Among these, flexographic printing is preferred because of 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 on one side of the plastic film 11, and examples thereof include reduced pressure 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 method for producing the laminate 20 in FIG. 2 includes the above-mentioned step (1) and step (2) in this order. In step (1), for example, a coating liquid is applied onto one surface of a plastic film 21, and then dried to form a first coating layer 22. In step (2), for example, a coating liquid is applied further onto the first coating layer 22, and then dried to form a second coating layer 23. Step (1) may be performed once, or may be repeated two or more times. That is, the coating liquid may be applied in multiple layers. Step (2) may be performed once, or may be repeated two or more times. That is, the coating liquid may be applied in multiple layers. The same methods as those used in the method for producing the laminate 10 can be applied as the coating method and drying method in steps (1) and (2).

[0100] <Modification> The laminate is not limited to the above-mentioned embodiment. For example, in the case of the laminate 10 shown in Fig. 1, the coating layer 12 is provided on the entire one side of the plastic film 11, but the coating layer 12 may be provided on a part of the one side of the plastic film 11. In this case, it is preferable that another coating layer is provided in the area on the 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 of a varnish composition.

[0101] Similarly, in the case of the laminate 20 shown in Fig. 2, the second coating layer 23 is provided over the entirety of one surface of the first coating layer 22, but the second coating layer 23 may be provided over only a portion of one surface of the first coating layer 22. In this case, it is preferable that another coating layer is provided in the region of one surface of the first coating layer 22 where the second coating layer 23 is not provided. The other coating layer may be, for example, a layer formed from a varnish composition.

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

[0103] <label> A label according to one embodiment of the present invention is obtained by using the laminate according to the present embodiment described above. The label can be used for various types of labels attached to packaging containers for beverages, seasonings, prepared foods, boxed lunches, and other foods and beverages, as well as daily necessities such as cosmetics. In particular, the label is suitable for use as a label for products whose packaging container is a plastic bottle, for example, as a label for bottled beverages and beverages. Examples of bottled beverages and beverages include beverages, liquid seasonings (dressings, noodle soup, soy sauce, liquid miso, etc.), and edible oils. The label may be in the form of, for example, a wrap label or a shrink label.

[0104] <Action and effect> As will be shown in the examples described later, by providing a coating layer (printed layer) on a plastic substrate using the aqueous liquid composition of this embodiment, it is possible to reduce the powdering phenomenon during the label attachment process. By using an aqueous binder resin (A), a large particle size wax (B) and a small particle size wax (C) having specific average particle size and penetration, and a specific resin (D) in a specific content, the powdering phenomenon was reduced, especially by using not one but two types of wax with different sizes.

[0105] Furthermore, the aqueous liquid composition, aqueous ink, and aqueous medium of this embodiment have good storage stability, and the stability of the coating liquid (two-component stability) when a curing agent is used is also good. Furthermore, a coating liquid containing the aqueous liquid composition of this embodiment also exhibits excellent adhesion of the coating layer to plastic substrates, excellent wet friction resistance, and excellent plate washability. In addition, water-based inks generally dry more slowly than oil-based inks, and if the aqueous medium in the coating layer does not dry sufficiently, blocking is likely to occur when the laminate (printed matter) after printing is rolled up; however, the coating liquid containing the aqueous liquid composition of this embodiment also has 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 as long as it does not deviate from the gist of the invention. In the following, "NV" stands for non-volatile content (solid content). "%" as a unit of content means "% by mass" unless otherwise specified. "Parts" means "parts by mass" unless otherwise specified.

[0107] [Raw materials used] <Water-based binder resin (A)> The following compounds were used as the aqueous binder resin (A) and the comparative component (A'). A-1: Water-based urethane resin (manufactured by Mitsui Chemicals, Inc., product name "Takelac W-5661", solid content 35% by mass). Hereinafter, also referred to as "U". A-2: Water-based acrylic urethane resin (manufactured by Covestro Coating Resins, product name "NeoPack E-315", solid content 35% by mass). Hereinafter, also referred to as "AU." A-3: Water-soluble acrylic resin (manufactured by BASF, product name "Joncryl 70J", solid content 30% by mass). Hereinafter also referred to as "A". A-4: Water-dispersible acrylic resin (acrylic resin emulsion, Seiko PMC Corporation product name "Hi-Loss X-ME-2039", solid content 48.5% by mass). Hereinafter also referred to as "AE". A'-5: Polyester resin (manufactured by Unitika Ltd., product name "Elitel KT-8803", solid content 30% by mass, Tg 65°C, number average molecular weight 15,000). A'-6: Chlorinated polyolefin (manufactured by Nippon Paper Industries Co., Ltd., product name "Superchlorine E-415", solid content 30% by mass).

[0108] <Large particle size wax (B)> The following large particle size wax (B) and comparative component (B') produced in Production 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 level 1. ·B'-9: Average particle size 3.0μm, penetration 40.

[0109] <Small particle size wax (C)> The following large particle size wax (C) and comparative component (C') produced in Production 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 rate 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 the resin (D) and the comparative component (D'). D-1: Polyethylene glycol modified styrene-maleic acid copolymer (manufactured by BYK Japan Co., Ltd., product name "DISPERBYK-2010", acid value 20 mg KOH / g). D-2: Polyethylene glycol modified styrene-maleic acid copolymer (manufactured by BYK Japan Co., Ltd., product name "DISPERBYK-190", acid value 10 mg KOH / g). D-3: Styrene-maleic acid copolymer (manufactured by BYK 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 (EVONIK, product name "Tegodisperse 760W", acid value 1mgKOH / g, contains styrene-maleic acid copolymer). D'-6: Modified polyurethane solution (BYK Japan Co., Ltd., DISPERBYK-184, solid content 52 mass%, acid value 0 mg KOH / g). D'-7: High molecular weight unsaturated carboxylic acid (AFCONA-5266, solid content 98% or more, acid value 250 mg KOH / g, manufactured by AFCONA).

[0111] <Hardening agent (E)> As the curing agent (E), the following compound was used. E-1: Isocyanate compound (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., product name "Hydrick FC Hardener"). E-2: Carbodiimide compound (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., product name "AB Hardener"). E-3: Aziridine compound (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., product name "Hydrick RA Hardener").

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

[0113] <Optional ingredients> - Defoamer: Manufactured by BYK Japan Co., Ltd., product name "BYK-028". Leveling agent: EVONIC product name "Surfynol 420". Beads: Acrylic beads (manufactured by Aica Kogyo Co., Ltd., product name "Ganz Pearl GM-0401S"). -Thickener: MUNZING product name "Tafigel PUR 45".

[0114] [Evaluation method] <Storage stability> 200 mL of the aqueous ink or aqueous medium (aqueous liquid composition) was placed in a container (a 300 mL beaker) and left to stand for one week in an atmosphere at 25° C. After one week, the container was shaken and the state of the liquid was visually observed. Evaluation was based on the following criteria. ◎: Maintains the same condition as at the start of storage. ◯: Slight separation or sedimentation, or thickening was observed. △: Clear separation or sedimentation is observed. ×: Severe separation or sedimentation or solidification.

[0115] <Two-liquid stability> A coating liquid was prepared by mixing an aqueous ink or aqueous medium (aqueous liquid composition) and a curing agent in a container (a 300 mL beaker) in an atmosphere of 25°C. Immediately after preparation (on the first day), the container was shaken and the state of the liquid was visually observed. In addition, the coating liquid was used for flexographic printing on the first and second days (24 hours) after preparation. Evaluation was based on the following criteria. ◎: On the first day, no increase in viscosity was observed and the ink remained in the same condition as the water-based ink before mixing. The ink was printable on both the first and second days. ○: Slight increase in viscosity was observed on the first day, but printing was possible. Printing was possible on the second day as well. △: Slight viscosity increase was observed on the first day, but printing was possible. On the second day, the ink thickened or solidified, making printing difficult. ×: Viscosity or solidification occurs to the extent that printing becomes difficult from the first day.

[0116] <Pot life> A coating solution was prepared by mixing the water-based ink and the curing agent in a container (a 300 mL beaker) in a 25°C atmosphere. Usability was judged after each elapsed time (1 hour, 2 hours, 4 hours, and 6 hours). In other words, the coating solution after the elapse of a given time was used for flexographic printing to judge whether it was printable or not. The obtained coating layer was stored in a 25°C atmosphere for 8 hours and then visually observed. ⊚: There is no increase in viscosity of the coating solution, and there are no problems with the coating layer after storage. ◯: The coating layer thickened, but printable, and there were no problems with the coating layer after storage. △: Viscosity of the coating layer is increased, but printing is possible. Slight unevenness is observed in the coating layer after storage, but within the acceptable range. ×: Printing is not possible, or printable but solid matter beyond the permissible range is observed in the coating layer after storage.

[0117] [Evaluation of coating layer] <Dust reduction test> A laminate having a white coating layer on a plastic substrate was cut into a 1 cm width to prepare a test specimen. A Gakushin-type friction fastness tester (manufactured by Tester Sangyo Co., Ltd., product name "AB-301") was used to conduct a test in which a piece of black cotton cloth was rubbed against the coating layers of 10 test specimens. The operating conditions were a load of 200 g and 10 back and forth strokes per test specimen. After the test, the condition of the black cloth and the coating layers of the test specimens was visually observed and evaluated according to the following criteria. In this test, if the evaluation is ⊚ or ◯, the powdering phenomenon caused by contact between the metal roll of the label attachment machine and the coating layer is successfully reduced, and it can be judged that the aqueous liquid composition has good powdering reduction properties. ◎: No white stains on the black cloth. ○: Only a small amount of white powder was attached to the black cloth. Δ: Clear white deposits were observed on the black cloth, but there was no area where the coating layer was lost on the test specimen. ×: 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 18 mm wide cellophane tape (manufactured by Nichiban Co., Ltd.) was attached to the surface of the coating layer laminated on the plastic substrate and pressed with a finger, and then the cellophane tape was quickly peeled off and the condition of the coating layer remaining on the plastic substrate was visually confirmed. 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 did not peel off at all (peeling rate: 0%). ○: Peeling rate is more than 0% and less than 50%. Δ: Peeling rate is 50% or more and less than 100%. ×: Peeling rate is 100%.

[0119] <Wet friction resistance test> Two days after forming the coating layer on the plastic substrate, the coating layer was rubbed with a black cotton cloth moistened with water using the Gakushin-type rub fastness tester. The operating conditions were: rub area 4 cm 2 After the test, the condition of the coating layer was visually observed, and the ratio of the area of ​​the fallen coating layer to the friction area (falling ratio) was calculated, and the wet friction resistance of the coating layer was evaluated according to the following criteria. ⊚: None of the coating layer fell off (fall-off rate: 0%). ○: Dropout rate is greater than 0% and less than 30%. △: Dropout rate is 30% or more and less than 50%. ×: Dropout rate is 50% or more.

[0120] <Blocking resistance test> A laminate having a white coating layer on a plastic substrate was laminated with the film used as the plastic substrate on the coating layer, and a test was performed in which the film was left to stand for 24 hours in a constant temperature chamber at 40°C without humidification while a load of 0.69 MPa was applied using a spring-loaded blocking tester. After the test, the blocking resistance of the coating layer was evaluated based on the peel resistance when the film was peeled off and the change in appearance of the coating layer (transfer to the film) according to the following criteria. ⊚: No peel resistance and no transfer of the coating layer to the film. ◯: There is a very slight resistance to peeling, but the coating layer does not transfer to the film. Δ: Slight peel resistance was felt, and slight transfer of the coating layer to the film was observed. ×: Strong resistance to peeling is felt, and most of the coating layer is transferred to the film.

[0121] <Plate cleaning test> The coating liquid was applied to an anilox roll and left for 6 hours at 20°C to form a coating film. The coating film was then rubbed and cleaned with a water-soaked melamine sponge. The ease of removing the coating film (plate cleanability) was evaluated according to the following criteria. ◎: The coating comes off with just a little rubbing. ○: The coating falls off after rubbing forcefully 20 times. △: The coating falls off after rubbing forcefully 50 times. ×: The coating film does not fall off.

[0122] <Production Example 1: Preparation of wax> 45 parts of a wax compound, pentaerythritol stearate 4-substituted (manufactured by Nippon Oil & Fats Corporation, product name "Unistar H-4 76"), 0.45 parts of 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 with a Disper Mixer (manufactured by Primix Corporation) to obtain a dispersion. The obtained dispersion was emulsified using a homogenizer (manufactured by Sugino Machine Co., Ltd.) under conditions of a temperature of 100° C. and a pressure of 4.9 MPa. Large particle size wax or small particle size wax was prepared while measuring the average particle size with a Coulter Counter type particle size distribution meter. The wax needle penetration depth was measured five times for each sample, and the three measured values ​​excluding the maximum and minimum values ​​were averaged to obtain the measurement result for each sample.

[0123] <Examples 1 to 33 and Comparative Examples 1 to 18> Examples 1 to 30 and Comparative Examples 1 to 14, 17, and 18 are examples in which aqueous inks containing an aqueous liquid composition and a pigment were prepared. Example 31 and Comparative Examples 15 and 16 are examples in which an aqueous liquid composition not containing a pigment was prepared as the aqueous medium. Examples 32 and 33 are examples in which the curing agent of Example 1 was changed.

[0124] A pre-dispersed mill base was prepared by mixing the aqueous binder (A), large particle size wax (B), small particle size wax (C), resin (D), defoamer, and, in the case of aqueous ink, pigment, according to the formulation shown in the table. The pre-dispersed mill base was then dispersed using a paint shaker device, after which a leveling agent, beads, thickener, and water were added to obtain an aqueous ink or aqueous medium. A mixture of the obtained water-based ink or water-based medium and a curing agent shown in the table was used as a coating liquid to produce a laminate by the following method.

[0125] (Manufacture of laminates) A recycled PET film (manufactured by Toyobo Co., Ltd., product name "Reshine", thickness 15 μm) was used as the plastic substrate. Cell volume 10.0cm 3 / m 2 A flexo hand proofer equipped with an anilox roll was used as an applicator to apply the coating solution of each example to one side of a plastic substrate so that the coating amount after drying was 2.0 g / m 2 The mixture was then dried for 1 minute with hot air from a dryer to form a coating layer (coating film), thereby obtaining a laminate (printed product). When the coating liquid was a water-based ink, a white coating layer was obtained, whereas when the coating liquid was a water-based medium, a thin white coating layer was obtained due to the inclusion of wax or the like.

[0126] (evaluation) The storage stability of the water-based ink or water-based medium was evaluated by the above method. The two-component stability of the coating liquid was evaluated by the above method. The coating layer of the laminate was evaluated for each item shown in the table by the above method. The results are shown in the table. A blank cell in the table means that the component is not blended (amount blended: 0 parts by mass). NV in the table means the non-volatile (solid) content of each component (unit: mass%). In the table, "(B) solid content / total solid content" means the content (unit: mass%) of the solid content of the large particle size wax (B) relative to the total mass of the solid content of the aqueous liquid composition. The same applies to "(C) solid content / total solid content" and "(D) solid content / total solid content." In the table, "(B):(C)" means the mass ratio of the solid contents of the large particle size wax (B) and the small particle size wax (C). In the table, "Urethane:acrylic urethane" refers to the mass ratio of the aqueous urethane resin to the aqueous 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 results in the table, Examples 1 to 33 were excellent in storage stability, powdering reduction, adhesion, wet friction resistance, blocking resistance, and plate cleanability. On the other hand, none of Comparative Examples 1 to 18 exhibited good storage stability, powdering reduction, adhesion, wet friction resistance, blocking resistance, and plate washability. In particular, the powdering reduction was inferior in all Comparative Examples compared to the evaluation of powdering reduction in the Examples.

[0142] (Application example) In Examples 1 to 33, a laminate was formed by forming one coating layer on a plastic film substrate, but laminates in which a second coating layer was formed in the same manner on the above coating layer (first coating layer) were also evaluated in the same manner as Examples 1 to 33, and it was found to be as excellent as Examples 1 to 33. The coating fluids for the second coating layer were the coating fluids of Examples 1 to 33, and it was confirmed that the coating fluids for the first coating layer and the second coating layer were excellent in the same manner as Examples 1 to 33, whether the combination was the same or different. [Explanation of symbols]

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

Claims

1. An aqueous liquid composition for use in coating a plastic substrate, comprising: An aqueous binder resin (A) which is at least one selected from the group consisting of an aqueous urethane resin, an aqueous acrylic resin, and an aqueous acrylic urethane resin; A large particle size wax (B) and a small particle size wax (C), and a resin (D) having a polymer chain containing a hydrophobic portion and a hydrophilic portion containing an acid group, 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 index 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 index of 0.1 or more and less than 15, The resin (D) has a hydrophobic portion having a constitutional unit derived from an ethylenically unsaturated monomer selected from the group consisting of styrene, α-methylstyrene, vinyltoluene, and derivatives thereof, a hydrophilic portion having a constitutional unit derived from an ethylenically unsaturated monomer selected from the group consisting of maleic anhydride, maleic acid, maleic acid monoester, and derivatives thereof, and has an acid value of 1 to 245 mgKOH / g; The aqueous liquid composition used for coating a plastic substrate, wherein the content of the solid content of the resin (D) is 0.1 to 18 mass% based on the total mass of the solid content of the aqueous liquid composition.

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

20.

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

25.

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

10.

5. The aqueous liquid composition according to claim 1, wherein the resin (D) comprises at least one selected from the group consisting of polyethylene glycol-modified styrene-maleic acid copolymers, styrene-maleic acid copolymers, phosphate esters of polyether-modified styrene-maleic acid copolymers, and styrene-maleic acid copolymers having phosphate esters.

6. The aqueous liquid composition according to claim 1 for use with a hardener.

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

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

9. A plastic substrate; A laminate comprising the plastic substrate and a coating layer formed from the coating liquid according to claim 8 .

10. A label obtainable using the laminate according to claim 9.

11. The label of claim 10 which is a label for a food or beverage product.

12. 11. The label of claim 10 which is a body wrap label.

Images