Aqueous liquid composition for plastic base material coating, aqueous varnish, aqueous medium, aqueous primer, aqueous ink, laminate, label and packaging material

Abstract

To provide an aqueous liquid composition which is excellent in glossiness, heat resistance and friction resistance of a coating film, has good adhesion to a plastic base material, can reduce tangling of a sheet, good storage stability of liquid, and good dispersibility when being blended with a pigment.SOLUTION: An aqueous liquid composition for plastic base material coating contains an acrylic resin (A) having an acid value (mgKOH / g) of 80 or more and 260 or less, an acrylic emulsion resin (B) having an acid value (mgKOH / g) of 10 or more and less than 80 and a glass transition temperature of 0 to 60°C, a solvent (C) represented by R1-O-(AO)n-R2, an aqueous medium (D) (excluding solvent (C)), a large particle diameter wax (E) having an average particle diameter of 1.5 μm or more, and a small particle diameter wax (F) having an average particle diameter of less than 1.5 μm, wherein with respect to the total mass of the solid content, a solid content of the acrylic resin (A) is 8.2 to 60 mass%, a solid content of the acrylic emulsion resin (B) is 20 to 82 mass%, a mass ratio B / A of the solid content is 0.25 to 10, and a mass ratio of a volatile component / C is 3 to 20.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an aqueous liquid composition for plastic substrates, an aqueous varnish, an aqueous medium, an aqueous primer, an aqueous ink, a laminate, a label and a packaging material. [Background technology]

[0002] Generally, printing is classified by the type of printing plate, with relief printing, intaglio printing, and lithographic printing being the most common printing methods. Other special printing methods include stencil printing such as silkscreen printing. For example, relief printing, such as flexography, uses a plate with raised image areas (the areas that become letters and pictures). Specifically, the area to be printed is raised higher than the rest, and ink is applied to this area with a roller, which is then pressed down onto the surface to be printed, transferring the ink to the surface.

[0003] With regard to inks used in printing, due to the growing awareness of reducing environmental impact in recent years, there has been an increasing demand for water-based inks that reduce organic solvent emissions during printing and residual solvents in the substrate. Because water-based inks have the property of easily penetrating paper, they have generally been used on paper substrates such as cardboard and paper bags. In addition, in flexographic printing, ink can seep into recessed areas rather than raised areas, and the ink that accumulates in the recessed areas can transfer to non-image areas, resulting in print smears (also known as plate entanglement). To date, water-based inks for flexographic printing (also called water-based flexographic inks) that improve plate entanglement and blocking have been proposed (Patent Document 1). In addition, water-based liquid inks that have viscosity stability, abrasion resistance, etc. have been proposed (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-203051 [Patent Document 2] Japanese Patent Publication No. 2019-094423 Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Documents 1 and 2, improvements to the properties of water-based flexographic inks, such as reduced plate entanglement, blocking resistance, abrasion resistance, and stability over time, have been investigated, but have not necessarily been sufficient. For example, conventional water-based flexographic inks have not achieved effects such as gloss and heat resistance on the printed surface. According to the findings of the present inventors, it is difficult to simultaneously satisfy these properties while also improving the storage stability of the ink composition and the dispersibility when a pigment is blended therein.

[0006] An object of the present invention is to provide an aqueous liquid composition for coating plastic substrates, which provides a coating film with excellent gloss, heat resistance, and abrasion resistance, has good adhesion to plastic substrates, reduces plate tangling when used in flexographic printing, and also has good storage stability of the liquid and good dispersibility when a pigment is blended therein. [Means for solving the problem]

[0007] The present invention has the following aspects. [1] An aqueous liquid composition used for coating a plastic substrate, an acrylic resin (A) having an acid value of 80 mgKOH / g or more and 260 mgKOH / g or less; an acrylic emulsion resin (B) having an acid value of 10 mgKOH / g or more and less than 80 mgKOH / g and a glass transition temperature of 0 to 60°C; a solvent (C) represented by the following formula (c1); an aqueous medium (D) (excluding the solvent (C)); A large particle size wax (E) having an average particle size of 1.5 μm or more; and a small particle size wax (F) having an average particle size of less than 1.5 μm, the content of the solid content of the acrylic resin (A) is 8.2 to 60 mass% and the content of the solid content of the acrylic emulsion resin (B) is 20 to 82 mass% relative to the total mass of the solid content of the aqueous liquid composition; B / A, which represents a mass ratio of the solid content of the acrylic emulsion resin (B) to the solid content of the acrylic resin (A), is 0.25 / 1 to 10 / 1; An aqueous liquid composition for coating a plastic substrate, wherein the mass ratio of the total volatile matter to the solvent (C) is volatile matter / C, which is 3 / 1 to 20 / 1. R 1 -O-(AO)nR 2 (c1) (R in the formula 1 , R 2 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R 1 and R 2 may be the same or different, A is a linear or branched alkylene group having 2 to 4 carbon atoms, n is an integer of 1 to 6, and when n is 2 or greater, the n As may be the same or different. [2] The aqueous liquid composition according to [1], wherein the acrylic resin (A) has a weight average molecular weight of 2,000 to 20,000. [3] The aqueous liquid composition according to [1] or [2], wherein the solvent (C) has a flash point of 0 to 140°C. [4] The aqueous liquid composition according to any one of [1] to [3], which has a flash point of more than 60°C. [5] The aqueous liquid composition according to any one of [1] to [4], wherein the total mass of the solid content of the aqueous liquid composition is 10 to 40 mass% relative to the total mass of the aqueous liquid composition. [6] The aqueous liquid composition according to any one of [1] to [5], wherein the boiling point of the solvent (C) is 170 to 250°C, and the content of the solvent (C) is 1 to 22 mass% relative to the total mass of the aqueous liquid composition. [7] The aqueous liquid composition according to any one of [1] to [6], wherein the solvent (C) comprises at least one selected from the group consisting of alkylene glycols, dialkylene glycols, monoalkylene glycol monoalkyl ethers, and dialkylene glycol monoalkyl ethers. [8] The large particle size wax (E) has an average particle size of 1.5 μm or more and 5 μm or less, and a penetration of 7 to 12, The aqueous liquid composition according to any one of [1] to [7], wherein the small particle size wax (F) has an average particle size of 0.4 μm or more and less than 1.5 μm and a penetration of 0.3 to 7. [9] The aqueous liquid composition according to any one of [1] to [8], wherein the total content of the solid content of the large particle size wax (E) and the solid content of the small particle size wax (F) is 1 to 20 mass% relative to the total mass of the solid content in the aqueous liquid composition.

[10] The aqueous liquid composition according to any one of [1] to [9], wherein C / (E+F), which represents the mass ratio of the content of the solvent (C) to the total content of the solid contents of the large particle wax (E) and the small particle wax (F), is 0.5 / 1 to 15 / 1.

[11] The aqueous liquid composition according to any one of [1] to

[10] , which is used together with a curing agent.

[12] The aqueous liquid composition according to any one of [1] to

[11] , which is used for one or more selected from aqueous varnishes, aqueous mediums, and aqueous primers.

[13] An aqueous ink comprising the aqueous liquid composition according to any one of [1] to

[11] and a pigment.

[14] A laminate having a printed layer formed by printing the water-based ink according to

[13] on a plastic substrate.

[15] The laminate according to

[14] , further comprising a white printed layer formed on the printed layer by printing a white ink for whitening.

[16] A laminate having a white printing layer formed by printing a white ink for whitening on a plastic substrate, and a printing layer formed by printing the water-based ink described in

[13] on top of the white printing layer.

[17] A laminate comprising a primer layer formed on a plastic substrate by applying an aqueous primer made of the aqueous liquid composition described in any one of [1] to

[11] , a printed layer formed on the primer layer by printing the aqueous ink described in

[13] , and a white printed layer formed on the printed layer by printing a white ink for underlining.

[18] A laminate comprising a primer layer formed on a plastic substrate by applying an aqueous primer made of the aqueous liquid composition described in any one of [1] to

[11] , a white printed layer formed on the primer layer by printing a white ink for underlayment, and a printed layer formed on the white printed layer by printing the aqueous ink described in

[13] .

[19] A laminate according to any one of

[14] to

[18] , having as an uppermost layer a varnish layer formed by applying an aqueous varnish made of the aqueous liquid composition according to any one of [1] to

[11] .

[20] The laminate according to any one of

[14] to

[19] , wherein the printed layer has a 60-degree specular gloss of 70% or more.

[21] A laminate comprising a plastic substrate, one or both of a primer layer not containing a pigment and provided in contact with the plastic substrate, and a varnish layer not containing a pigment and provided as the top layer, and a printed layer containing a pigment, and at least one of the primer layer, the varnish layer, and the printed layer containing the pigment is a layer formed by applying a coating liquid containing the aqueous liquid composition described in any one of [1] to

[11] .

[22] The laminate according to

[21] , wherein the layer formed by applying a coating liquid containing the aqueous liquid composition has a 60 degree specular gloss of 70% or more.

[23] A label or packaging material obtained by using the laminate according to any one of

[14] to

[22] above. [Effects of the Invention]

[0008] The present invention provides an aqueous liquid composition for coating plastic substrates, which provides a coating film with excellent gloss, heat resistance, and abrasion resistance, has good adhesion to plastic substrates, reduces plate entanglement when used in flexographic printing, and also has good storage stability and dispersibility when a pigment is blended therein. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view schematically illustrating an example of a laminate of the present invention. [Figure 2] FIG. 2 is a cross-sectional view schematically showing another example of the laminate of the present invention. [Figure 3] FIG. 2 is a cross-sectional view schematically showing another example of the laminate of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] The term "aqueous" in the aqueous liquid composition means that it 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 of the aqueous liquid composition, such as water and organic solvents. 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 remaining content is defined as the volatile content. "Acrylic resin" means a polymer containing monomer units derived from (meth)acrylate. "(Meth)acrylate" is a general term for "acrylate" and "methacrylate." "(Meth)acrylic acid" is a general term for "acrylic acid" and "methacrylic acid." "(Meth)acrylamide" is a general term for "acrylamide" and "methacrylamide." The symbol "to" indicating a range of values ​​means that the values ​​before and after it are included as the lower and upper limits. The lower and upper limits of the ranges disclosed in this specification can be combined in any way to create new ranges.

[0012] The weight average molecular weight of the 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 a resin is measured in accordance with JIS K 7121:2012 as follows: A differential scanning calorimeter is used to measure 10 mg of the resin to be measured, and the temperature is raised from −100° C. to 160° C. at a rate of 20° C. / min to obtain a curve (DSC curve), from which the baseline and the tangent to the endothermic curve intersect. The acid value of a resin is the amount of potassium hydroxide required to neutralize acid groups such as carboxyl groups per gram of solid content of a sample, expressed in milligrams, and is measured in accordance with JIS K 5601-2-1:1999.

[0013] 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 for electrically measuring the particle size and particle size distribution of wax particles dispersed in a solution by passing them through a fine hole and observing the change in the electrical signal as the particles pass through. The wax penetration is measured according to 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 then penetrated into the sample for 5 seconds, and the depth of penetration is measured. The sample temperature is 25°C.

[0014] <Aqueous liquid composition for coating plastic substrates> An aqueous liquid composition for coating plastic substrates according to one embodiment of the present invention (hereinafter also simply referred to as "aqueous liquid composition") contains an acrylic resin (A), an acrylic emulsion resin (B), a solvent (C), a large particle size wax (E), a small particle size wax (F), and water. A pigment can be blended into the aqueous liquid composition to produce an aqueous ink. The aqueous liquid composition does not contain a pigment and can be used as an aqueous medium, an aqueous varnish, an aqueous primer, or the like, which is a liquid for adjusting the hue of an aqueous ink. If necessary, the composition may further contain optional components within the range that does not impair the effects of the present invention. The aqueous liquid composition of the present embodiment is used for coating a plastic substrate. The type of plastic substrate can be appropriately selected depending on the application and is not particularly limited. Details of the plastic substrate will be described later.

[0015] <Acrylic resin (A)> The acrylic resin (A) is an acrylic resin (excluding acrylic emulsion resins) with an acid value of 80 mgKOH / g or more and 260 mgKOH / g or less. The acrylic resin (A) contributes to the dispersibility of pigments, the storage stability of the coating liquid, the reduction of plate entanglement, and the gloss of the coating layer. Examples of the acrylic resin (A) include a homopolymer of (meth)acrylate, a copolymer of two or more kinds of (meth)acrylate, and a copolymer of (meth)acrylate and a monomer other than (meth)acrylate. The proportion of (meth)acrylate units to the total mass of all monomer units constituting the acrylic resin is preferably 10 to 100 mass%, more preferably 20 to 100 mass%.

[0016] 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.

[0017] Examples of monomers other than (meth)acrylates include conjugated diene compounds such as 1,3-butadiene, isoprene, and chloroprene; aromatic vinyl compounds such as styrene, α-methylstyrene, halogenated styrene, and divinylbenzene; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; acrylamides such as N,N-dimethyl(meth)acrylamide and N,N-diethyl(meth)acrylamide; unsaturated carboxylic acids such as (meth)acrylic acid, itaconic acid, maleic acid, and fumaric acid; and unsaturated carboxylic acid esters such as diethyl maleate, dibutyl maleate, dibutyl fumarate, diethyl itaconate, and dibutyl itaconate. These monomers may be used alone or in combination of two or more.

[0018] The acid value of the acrylic resin (A) is 80 mgKOH / g or more and 260 mgKOH / g or less, preferably 100 to 255 mgKOH / g, and more preferably 120 to 250 mgKOH / g from the viewpoint of dispersibility and storage stability. When the acid value of the acrylic resin (A) is equal to or greater than the above-mentioned lower limit, the dispersibility of the pigment and the storage stability of the coating liquid are easily improved. In addition, the reduction in plate smearing and the heat resistance of the coating layer are easily improved. When the acid value of the acrylic resin (A) is equal to or less than the above-mentioned upper limit, the adhesion to the plastic substrate and the abrasion resistance of the coating layer are easily improved. When the acid value of the acrylic resin (A) is within the above-mentioned range, the dispersibility, storage stability, reduction in plate smearing, adhesion, heat resistance, and abrasion resistance of the coating layer are easily improved. If the acid value of the acrylic resin (A) is less than 80 mgKOH / g, the dispersibility, storage stability, and heat resistance will be poor, and if it exceeds 260 mgKOH / g, the abrasion resistance will be poor.

[0019] The glass transition temperature of the acrylic resin (A) is preferably 0 to 140° C., more preferably 10 to 130° C., even more preferably 20 to 120° C., and particularly preferably 50 to 110° C. When the glass transition temperature of the acrylic resin (A) is at least the lower limit, the blocking resistance of the coating layer is likely to be improved, and when it is at most the upper limit, the adhesion to the plastic substrate is likely to be improved.

[0020] The weight-average molecular weight of the acrylic resin (A) is preferably 2,000 to 20,000, more preferably 5,000 to 20,000. When the weight-average molecular weight of the acrylic resin (A) is at least the above-mentioned lower limit, the solvent resistance and blocking resistance of the coating layer are easily improved, and when it is at most the above-mentioned upper limit, the adhesion to plastic films is easily improved.

[0021] The acrylic resin (A) is 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 the monomer component is polymerized by a solution polymerization method, a bulk polymerization method, an emulsion polymerization method, or the like in the presence of a known radical polymerization initiator. The acrylic resin (A) may be a self-crosslinking type.

[0022] As the acrylic resin (A), 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 acrylic resin (A) may be used alone or in combination of two or more kinds.

[0023] <Acrylic emulsion resin (B)> The acrylic emulsion resin (B) is an acrylic emulsion resin having an acid value of 10 mgKOH / g or more and less than 80 mgKOH / g and a glass transition temperature of 0 to 60° C. The acrylic emulsion resin (B) contributes to the adhesion to the plastic substrate and the heat resistance and abrasion resistance of the coating layer. As the acrylic emulsion resin (B), it is preferable to use a water-dispersible acrylic emulsion resin. As the water-dispersible acrylic emulsion resin, for example, a core-shell type resin having an acrylic resin in the shell portion can be suitably used.

[0024] The acid value of the acrylic emulsion resin (B) is 10 mgKOH / g or more but less than 80 mgKOH / g, preferably 15 to 80 mgKOH / g, and more preferably 25 to 75 mgKOH / g from the viewpoint of adhesion and heat resistance. When the acid value of the acrylic emulsion resin (B) is equal to or greater than the lower limit, the dispersibility of the pigment and the storage stability and heat resistance of the coating liquid are easily improved, while when it is equal to or less than the upper limit, the adhesion to the plastic substrate is easily improved. In addition, by keeping the acid value of the acrylic emulsion resin (B) within the above range, the dispersibility, storage stability, heat resistance and adhesion of the coating film are easily improved. When the acid value of the acrylic emulsion resin (B) is less than 10 mgKOH / g, the storage stability and heat resistance are poor, and when it is 80 mgKOH / g or more, the adhesion is poor.

[0025] The glass transition temperature of the acrylic emulsion resin (B) is 0 to 60°C, and preferably 10 to 50°C from the viewpoints of gloss, adhesion, heat resistance, and abrasion resistance. When the glass transition temperature of the acrylic emulsion resin (B) is at least the lower limit, the heat resistance and abrasion resistance of the coating layer are easily improved, and when it is at most the upper limit, the adhesion to the plastic substrate and the reduction of plate entanglement are easily improved. When the glass transition temperature of the acrylic emulsion resin (B) is less than 0°C, the heat resistance and abrasion resistance are poor, and when it is more than 60°C, the adhesion is poor.

[0026] The acrylic emulsion resin (B) 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 using a polymer emulsifier method. As the acrylic emulsion resin (B), commercially available products can also be used. Commercially available acrylic emulsion resins (B) include, for example, products manufactured by Seiko PMC Corporation under the 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" and BASF Japan Ltd. product names: "Joncryl PDX-7616A," "Joncryl PDX-7356," "Joncryl PDX-7777," "Joncryl PDX-7357," "Joncryl PDX-7182," "Joncryl PDX-7326," "Joncryl PDX-7732," "Joncryl PDX-7741," "Joncryl PDX-7787," "Joncryl PDX-7734," "Joncryl PDX-7615," and "Joncryl PDX-77 Examples of such products include "Joncryl PDX-75," "Joncryl PDX-7692," "Joncryl PDX-7630A," "Joncryl PDX-7158," "Joncryl 352D," "Joncryl PDX-7199," "Joncryl PDX-7358," "Joncryl PDX-7667," "Joncryl PDX-7700," "Joncryl PDX-7696," "Joncryl PDX-7780," "Joncryl PDX-7177," and "Joncryl PDX-7430," and Aica Kogyo Co., Ltd. products under the 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," and "Ultrasol UL-1097."

[0027] <Solvent (C)> The solvent (C) is a glycol-based solvent represented by the following formula (c1): The solvent (C) may be used alone or in combination of two or more kinds. The solvent (C) contributes to reducing plate entanglement. R 1 -O-(AO)nR 2 (c1) In formula (c1), R 1 , R 2 are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R 1 and R 2 may be the same or different from each other. A is a linear or branched alkylene group having 2 to 4 carbon atoms, and n is an integer of 1 to 6. When n is 2 or more, the n As may be the same or different. A preferably has 2 or 3 carbon atoms, and more preferably 3. n is preferably 1 to 5, more preferably 1 to 4, and even more preferably 1 to 3.

[0028] Examples of the solvent (C) include alkylene glycol, dialkylene glycol, trialkylene glycol, monoalkylene glycol monoalkyl ether, polyalkylene glycol monoalkyl ether, and the like. Alkylene glycol (n=1, R 1 , R 2 is a hydrogen atom), propylene glycol, butylene glycol, etc. Dialkylene glycol (n=2, R 1 , R 2 is a hydrogen atom), dipropylene glycol, diethylene glycol, etc. Trialkylene glycol (n=3, R 1 , R 2 is a hydrogen atom), examples of which include tripropylene glycol and triethylene glycol. Monoalkylene glycol monoalkyl ether (n=1, R 1 , R 2wherein one is a hydrogen atom and the other is an alkyl group), examples thereof include propylene glycol monoalkyl ethers such as propylene glycol monomethyl ether (also known as methyl propylene glycol), propylene glycol monoethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether. Polyalkylene glycol monoalkyl ether (n=2 or more, R 1 , R 2 wherein one is a hydrogen atom and the other is an alkyl group), examples thereof include dipropylene glycol monoalkyl ethers such as dipropylene glycol monomethyl ether and dipropylene glycol monoethyl ether; tripropylene glycol monoalkyl ethers such as tripropylene glycol monomethyl ether and tripropylene glycol monoethyl ether; and diethylene glycol monoalkyl ethers such as diethylene glycol monomethyl ether, diethylene glycol monoethyl ether and diethylene glycol monobutyl ether.

[0029] The aqueous liquid composition preferably has a flash point of more than 60° C. If the flash point is more than 60° C., the composition does not fall under the category of dangerous goods under the United Nations Recommendations on Dangerous Goods, and is easy to handle. In order to make it easier to make the flash point of the aqueous liquid composition exceed 60° C., the flash point of the solvent (C) is preferably 0° C. or higher, more preferably 10° C. or higher, and even more preferably 20° C. or higher. In terms of drying properties, the upper limit of the flash point of the solvent (C) is preferably 140° C. or lower, more preferably 135° C. or lower, and even more preferably 130° C. or lower. When two or more compounds are used as the solvent (C), the above values ​​are the flash points of the respective compounds.

[0030] The boiling point of the solvent (C) is preferably 170 to 250° C., more preferably 170 to 245° C., and from the viewpoint of drying properties, even more preferably 170 to 240° C. If the boiling point of the solvent (C) is not less than the above lower limit, the plate entanglement reduction property is easily improved, and if it is not more than the above upper limit, the drying properties are easily improved.

[0031] The solvent (C) preferably has a solubility in water at 20°C (unit: g / 100 g-H2O) of 5 g / 100 g-H2O or more, more preferably 30 g / 100 g-H2O or more, and from the viewpoint of compatibility, even more preferably 50 g / 100 g-H2O or more.

[0032] In terms of compatibility in the aqueous liquid composition, the solvent (C) preferably contains at least one selected from the group consisting of alkylene glycol, dialkylene glycol, monoalkylene glycol monoalkyl ether, and dialkylene glycol monoalkyl ether. In particular, it is more preferable that the solvent (C) contains a solvent (C') which is at least one selected from propylene glycol, dipropylene glycol, and propylene glycol monomethyl ether. The content of solvent (C') relative to the total mass of solvent (C) may be 50 mass% or more, 60 mass% or more, 70 mass% or more, 80 mass% or more, 90 mass% or more, or 95 mass% or more, or may be 100 mass%.

[0033] <Aqueous medium (D)> The aqueous liquid composition of this embodiment contains an aqueous medium. The aqueous medium (D) contributes to reducing plate entanglement. Examples of aqueous media include water and mixed solvents of water and organic solvents (excluding solvent (C)). The organic solvent in the mixed solvent is not particularly limited as long as it is soluble in water, and examples include alcohol-based solvents such as methanol, ethanol, propanol, n-butanol, and i-butanol; and ketone-based solvents such as acetone. 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% by mass, more preferably from 70 to 100% by mass, and even more preferably from 80 to 100% by mass.

[0034] <Wax> As the wax to be contained in the aqueous liquid composition, a large particle size wax (E) and a small particle size wax (F) having different average particle sizes are used in combination. The large particle size wax (E) and the small particle size wax (F) may be made of the same material or different materials, but from the viewpoint of compatibility, they are preferably made of the same material.

[0035] Examples of materials for the large particle size wax (E) and the small particle size wax (F) 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); and carboxylic acid esters or partial esters of polyhydric alcohols obtained by reacting polyhydric alcohols (such as glycerin and pentaerythritol) with long-chain fatty acids. The large particle size wax (E) and the small particle size wax (F) may be produced by a known method, may be a natural product, or may be a commercially available product. The large particle size wax (E) or the small particle size wax (F) may also be obtained by adjusting the particle size of a commercially available wax compound.

[0036] Examples of polyethylene waxes include high density polymerized polyethylene, low density polymerized polyethylene, oxidized polyethylene, acid-modified polyethylene, and special monomer-modified polyethylene. Fischer-Tropsch wax is a wax produced by the Fischer-Tropsch process using carbon monoxide and hydrogen as raw materials, and has a nearly saturated, unbranched, linear molecular structure. Paraffin wax can be produced by known methods for producing paraffin wax, such as solvent fractionation, distillation fractionation, and urea dewaxing.

[0037] Commercially available polyethylene waxes include those manufactured by Mitsui Chemicals, Inc. under the product names "Chemipearl W100," "Chemipearl W200," "Chemipearl W300," "Chemipearl W308," "Chemipearl W400," "Chemipearl W401," "Chemipearl W500," "Chemipearl W640," "Chemipearl W700," and "Chemipearl 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 "JonCrylwax 4" manufactured by BASF Japan.

[0038] <Large particle wax (E)> The large particle size wax (E) preferably has an average particle size of 1.5 μm or more and 5 μm or less, and a penetration of 7 to 12. The large particle size wax (E) contributes to the abrasion resistance and gloss of the coating layer. The average particle size of the large particle size wax (E) is more preferably 1.5 to 4.5 μm. When the average particle size of the large particle size wax (E) is at least the lower limit of the above range, it is easy to improve abrasion resistance. When it is at most the upper limit of the above range, it is easy to improve gloss. When the average particle size of the large particle size wax (E) is less than 1.5 μm, abrasion resistance is poor. The penetration of the large particle size wax (E) is more preferably 8 to 12, and even more preferably 8 to 11. When the penetration of the large particle size wax (E) is at least the lower limit of the above range, the abrasion resistance is easily improved. When it is at most the upper limit of the above range, the blocking resistance is easily improved.

[0039] <Small particle size wax (F)> The small particle size wax (F) preferably has an average particle size of 0.4 μm or more and less than 1.5 μm, and a penetration of 0.3 to 7. The small particle size wax (F) contributes to the abrasion resistance and gloss of the coating layer. The average particle size of the small particle size wax (F) is more preferably 0.6 to 1.5 μm. When the average particle size of the small particle size wax (F) is equal to or greater than the lower limit of the above range, glossiness is easily increased. When it is equal to or less than the upper limit of the above range, abrasion resistance is easily increased. When the average particle size of the small particle size wax (F) is 1.5 μm or more, glossiness is poor. The penetration of the small particle size wax (F) is more preferably 1 to 7, and even more preferably 1 to 6. When the penetration of the small particle size wax (F) is at least the lower limit of the above range, the abrasion resistance is easily improved. When it is at most the upper limit of the above range, the blocking resistance is easily improved.

[0040] <Optional ingredients> The aqueous liquid composition may contain optional components other than the above components, if necessary. As optional components, known additives for use in coating solutions for plastic substrates can be used, such as thickeners, anti-settling agents, UV absorbers, antioxidants, leveling agents, viscoelasticity modifiers, surface tension modifiers, rheology modifiers, light stabilizers, antifoaming agents, lubricants, dispersants, stabilizers, pH adjusters, fillers, antifungal agents, antistatic agents, metal fine particles, and magnetic powders. The optional components may be used alone or in combination of two or more.

[0041] <Composition of aqueous liquid composition> [Total solids] The total solid content (total mass of solids) of the aqueous liquid composition is preferably 10 to 40 mass %, more preferably 15 to 35 mass %, relative to the total mass of the aqueous liquid composition. When the total solid content of the aqueous liquid composition is equal to or greater than the lower limit of the above range, stability is likely to be improved. When it is equal to or less than the upper limit of the above range, adhesion to plastic substrates is likely to be improved.

[0042] [Acrylic resin (A)] The solid content of the acrylic resin (A) relative to the total solid content of the aqueous liquid composition is 8.2 to 60 mass%, preferably 8.5 to 59 mass%, and more preferably 9 to 58 mass% from the viewpoints of dispersibility, storage stability, adhesion, heat resistance, and abrasion resistance. When the solid content of the acrylic resin (A) is at or above the lower limit of the above range, the dispersibility of the pigment and the storage stability of the coating liquid are likely to be improved. When it is at or below the upper limit of the above range, the adhesion to the plastic substrate and the heat resistance and abrasion resistance of the coating layer are likely to be improved. When the solid content of the acrylic resin (A) relative to the total solid content of the aqueous liquid composition is less than 8.2 mass%, dispersibility and storage stability are poor, and when it exceeds 60 mass%, the adhesion to the plastic substrate and the heat resistance and abrasion resistance of the coating layer are poor.

[0043] [Acrylic emulsion resin (B)] The solid content of the acrylic emulsion resin (B) relative to the total solid content of the aqueous liquid composition is 20 to 82 mass%, preferably 24 to 81 mass%, and more preferably 28 to 80 mass% from the viewpoints of dispersibility, adhesion, heat resistance, and abrasion resistance. When the solid content of the acrylic emulsion resin (B) is at or above the lower limit of the above range, adhesion to the plastic substrate and heat resistance and abrasion resistance of the coating layer are improved, while when it is at or below the upper limit of the above range, pigment dispersibility is easily improved. When the solid content of the acrylic emulsion resin (B) relative to the total solid content of the aqueous liquid composition is less than 20 mass%, adhesion, heat resistance, and abrasion resistance are poor, and when it exceeds 82 mass%, dispersibility is poor.

[0044] [B / A] B / A, which represents the mass ratio of the solid content of the acrylic emulsion resin (B) to the solid content of the acrylic resin (A) contained in the aqueous liquid composition, is 0.25 / 1 to 10 / 1, preferably 0.3 / 1 to 9.5 / 1, and more preferably 0.35 / 1 to 9 / 1 from the viewpoints of dispersibility, adhesion, heat resistance, and abrasion resistance. When B / A is equal to or greater than the lower limit of the above range, adhesion, heat resistance, and abrasion resistance are likely to be improved. When B / A is equal to or less than the upper limit of the above range, dispersibility is likely to be improved. When B / A, which represents the mass ratio of the solid content of the acrylic emulsion resin (B) to the solid content of the acrylic resin (A), is less than 0.25 / 1, adhesion, heat resistance, and abrasion resistance are poor, and when it exceeds 10 / 1, dispersibility is poor.

[0045] [Solvent (C)] The content of the solvent (C) is preferably 1 to 22% by mass, and more preferably 4 to 21% by mass, relative to the total mass of the aqueous liquid composition, from the viewpoint of reducing plate tangling. When the content of the solvent (C) is equal to or greater than the lower limit of the above range, adhesion to the plastic substrate and wet rub resistance of the coating layer are likely to be improved. When the content is equal to or less than the upper limit of the above range, plate tangling is likely to be reduced.

[0046] [Total volatiles / solvent (C)] The total volatile content is the total of the components of the aqueous liquid composition other than the total solid content, and is the sum of the solvent (C), the aqueous medium, and other volatile components. The ratio volatiles / C, which represents the mass ratio of the total volatiles to the solvent (C), is 3 / 1 to 20 / 1, and is more preferably 3 / 1 to 19.5 / 1 from the viewpoints of plate entanglement reduction, abrasion resistance, and adhesion. When the ratio volatiles / C is equal to or greater than the lower limit of the above range, plate entanglement reduction is likely to be improved. When the ratio is equal to or less than the upper limit of the above range, adhesion to the plastic substrate and abrasion resistance of the coating layer are likely to be improved. When the ratio volatiles / C, which represents the mass ratio of the total volatiles to the solvent (C), is less than 3 / 1, plate entanglement reduction is poor, and when it is 20 / 1, abrasion resistance and adhesion are poor.

[0047] [Large particle size wax (E) + Small particle size wax (F)] The total content of the solid content of the large particle size wax (E) and the solid content of the small particle size wax (F) relative to the total solid content of the aqueous liquid composition is preferably 1 to 20 mass%, and more preferably 2 to 18 mass% from the viewpoints of dispersibility and storage stability. When the total wax solid content relative to the total solid content of the aqueous liquid composition is equal to or greater than the lower limit of the above range, dispersibility and storage stability are likely to be improved. When it is equal to or less than the upper limit of the above range, adhesion, heat resistance, and abrasion resistance are likely to be improved.

[0048] [C / (E+F)] C / (E+F), which represents the mass ratio of the content of the solvent (C) to the total content of the solids of the large particle wax (E) and the small particle wax (F), is preferably 0.5 / 1 to 15 / 1, more preferably 0.5 / 1 to 14 / 1. When C / (E+F) is in the above range, the dispersibility of the pigment, the storage stability, heat resistance, and abrasion resistance of the coating liquid are likely to be improved.

[0049] [Application] The aqueous liquid composition of this embodiment can be used as an aqueous medium. The aqueous medium is used as a hue adjusting liquid by mixing with an aqueous ink. The aqueous liquid composition of this embodiment can also be suitably used as an aqueous varnish for forming a varnish layer or an aqueous primer for forming a primer layer.

[0050] <Method for producing aqueous liquid composition> The aqueous liquid composition of this embodiment can be obtained by mixing, for example, an acrylic resin (A), an acrylic emulsion resin (B), a solvent (C), an aqueous medium (D), a large particle size wax (E), a small particle size wax (F), 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.

[0051] <Pigment / Water-based ink> The aqueous ink of this embodiment contains the aqueous liquid composition of this embodiment and a pigment. Examples of pigments include conventional organic and inorganic pigments used in general inks, paints, and recording materials. Examples of organic pigments include phthalocyanine pigments (e.g., phthalocyanine blue and phthalocyanine green), azo pigments (e.g., monoazo and condensed azo), threne pigments (e.g., anthraquinone, perinone, perylene, and thioindigo), quinacridone pigments, dioxazine pigments, isoindolinone pigments, pyrrolopyrrole pigments, aniline black, and organic fluorescent pigments. Examples of inorganic pigments include natural products (e.g., clay), ferrocyanides (e.g., Prussian blue), sulfides (e.g., zinc sulfide), sulfates, oxides (e.g., titanium oxide, chromium oxide, zinc oxide, and iron oxide), hydroxides (e.g., aluminum hydroxide), silicates (e.g., ultramarine), carbonates, carbon (e.g., carbon black and graphite), metal powders (e.g., aluminum powder, bronze powder, and zinc powder), and calcined pigments.

[0052] The content of the pigment is preferably 1 to 60% by mass relative to the total mass of the water-based ink. When an organic pigment is used as the pigment, 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 the pigment, the content of the inorganic pigment is preferably 10 to 60% by mass relative to the total mass of the water-based ink.

[0053] The content of solvent (C) is preferably 1 to 20 mass% relative to the total mass of the water-based ink, and more preferably 5 to 19 mass% from the viewpoint of reducing plate tangling. When the content of solvent (C) is equal to or greater than the lower limit of the above range, adhesion to the plastic substrate and wet rub resistance of the coating layer are likely to be improved. When the content is equal to or less than the upper limit of the above range, plate tangling is likely to be reduced.

[0054] The aqueous ink of this embodiment may be used as is as a liquid (coating liquid) to be applied to a plastic substrate, or may be diluted with water or an alcohol solvent before use, or a mixture of the aqueous ink and an aqueous medium may be used as a coating liquid.

[0055] <Water-based ink / water-based medium> When an aqueous ink and an aqueous medium are mixed, the combination of the aqueous medium and the aqueous ink to be mixed is preferably the aqueous medium of this embodiment and the aqueous ink of this embodiment. The composition of the aqueous ink other than the pigment may be the same as or different from the composition of the aqueous medium. It is more preferable that they are the same. The composition of the coating liquid obtained by mixing the aqueous medium of this embodiment with the aqueous ink of this embodiment is preferably the preferred composition of the aqueous ink of this embodiment.

[0056] <Curing agent> The aqueous liquid composition of this embodiment may be used together with a curing agent. For example, a coating liquid may be prepared by mixing the aqueous liquid composition with a curing agent, and the resulting coating liquid may be applied to a plastic substrate. Alternatively, a coating liquid may be prepared by mixing an aqueous ink containing the aqueous liquid composition of this embodiment and a pigment with a curing agent. Use of a curing agent further improves the coating film properties such as water resistance and abrasion resistance of the coating layer, as well as adhesion to plastic substrates.

[0057] As the curing agent, those known in the field of coating liquids can be used, and examples thereof include isocyanate-based curing agents, blocked isocyanate-based curing agents, carbodiimide-based curing agents, oxazoline-based curing agents, epoxy-based curing agents, and aziridine-based curing agents. The curing agents may be used alone or in combination of two or more.

[0058] <Laminate> 1 to 3 are cross-sectional views each showing a schematic representation of an embodiment of the laminate of the present invention, and the dimensional ratios in Figs. 1 to 3 are different from the actual ratios for the sake of convenience of explanation. When the laminates of FIGS. 1 to 3 are used as labels or packaging materials, the surface that is visible is referred to as the front surface, and the opposite surface is referred to as the back surface. The laminate 10 in FIG. 1 includes a plastic film 11 that is a plastic substrate, and a coating layer 12 provided on the back surface of the plastic film 11. The laminate 20 in Figure 2 comprises a plastic film 21 as a substrate, a first coating layer 22 provided on the back surface of the plastic film 21, and a second coating layer 23 provided on the back surface of the first coating layer 22. The laminate 30 in Figure 3 comprises a plastic film 31 as a substrate, a second coating layer 33 provided on the surface of the plastic film 31, and a first coating layer 32 provided on the surface of the second coating layer 33.

[0059] In the laminates 20, 30, the first coating layers 22, 32 are, for example, color printed layers printed using a coating liquid containing a pigment to impart design, functionality, and the like. The second coating layers 23, 33 are white coating layers (white printed layers) formed using white ink for the purposes of protecting the color printed layers and imparting hiding properties. The plastic film 21 in the laminate 20 has transparency sufficient to allow the first coating layer 22, which is a color print layer, to be visible.

[0060] The coating layer 12 in the laminate 10 and the first coating layers 22 and 32 in the laminates 20 and 30 are coating layers (hereinafter also referred to as "the present coating layers") formed using a coating liquid containing the aqueous liquid composition of this embodiment described above. The coating layer 12 and the first coating layers 22 and 32 may have a single-layer structure or a multi-layer structure in which the coating liquid is applied multiple times. The thickness (total thickness) of the coating layer 12 and the first coating layers 22 and 32 is, for example, preferably 0.2 to 15 μm, more preferably 0.3 to 10 μm, and even more preferably 0.3 to 8 μm.

[0061] In the laminates 20 and 30, the composition of the second coating layers 23 and 33 laminated in contact with the main coating layers (first coating layers 22 and 32) is not particularly limited. From the viewpoint of gloss, the second coating layers 23 and 33 are preferably coated using a water-based ink containing an acrylic resin as a binder resin. The thickness of the second coating layers 23 and 33 is preferably 0.2 to 3.0 μm, more preferably 0.3 to 2.0 μm, and even more preferably 0.3 to 1.5 μm.

[0062] <Plastic substrate> The type of plastic film 11, 21, 31 that is the plastic substrate can be appropriately selected depending on the use of the laminate 10, 20, 30, etc. Examples of materials for the plastic films 11, 21, and 31 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.

[0063] When the laminates 10, 20, 30 are used as heat-shrinkable labels (shrink labels), the plastic films 11, 21, 31 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, 30 are used as drum-wrapped labels (roll labels), the plastic films 11, 21, 31 can be either stretched or unstretched plastic films, such as biaxially stretched PP film (OPP film) and unstretched PP film. When the laminates 10, 20, 30 are used as packaging materials, the plastic films 11, 21, 31 are preferably high-density polyethylene films, low-density polyethylene films, linear polyethylene films, or biaxially oriented polyester films.

[0064] The plastic films 11, 21, and 31 may have a single-layer structure or a laminate structure. That is, the plastic films 11, 21, and 31 may be single-layer films or laminate films. When the plastic films 11 and 21 are laminate films, they may be configured by laminating two or more films of the same type, or by laminating two or more films of different types. Examples of preferred film combinations include a combination in which a polyester film is used on the front side of plastic films 11, 21, and 31 and a polystyrene film or polyolefin film is used on the back side of plastic films 11, 21, and 31, and a combination in which a cyclic polyolefin film is used on the front side of plastic films 11, 21, and 31 and a polyethylene film or polypropylene film is used on the back side of plastic films 11, 21, and 31.

[0065] The plastic films 11, 21, and 31 may be subjected to surface treatment such as corona discharge treatment, plasma treatment, flame treatment, and solvent treatment, if necessary.

[0066] When the laminates 10, 20, 30 are used as labels, the thickness of the plastic films 11, 21, 31 is preferably 5 to 100 μm, more preferably 12 to 60 μm, and even more preferably 12 to 50 μm. When the laminates 10, 20, 30 are used as packaging materials, the thickness of the plastic films 11, 21, 31 is preferably 5 to 100 μm, more preferably 12 to 80 μm, and even more preferably 20 to 70 μm.

[0067] [60 degree specular gloss] The present coating layer (e.g., color print layer, white print layer, varnish layer, medium layer, primer layer) formed using a coating liquid (e.g., aqueous ink, aqueous varnish, aqueous medium, aqueous primer) containing the aqueous liquid composition of this embodiment has excellent surface gloss. Specifically, using the present coating layer as the measurement subject, a 60-degree specular gloss of 70% or more can be obtained as measured by the method described in the Examples below. The gloss is preferably 75% or more. By ensuring that the gloss is above the above lower limit, the appearance will be excellent.

[0068] <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 method for producing the laminate 10 of 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 Figure 2 includes a step (1) of forming a first coating layer 22 on one side 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. The manufacturing method of the laminate 30 in Figure 3 includes a step (2) of forming a second coating layer 33 on one side of a plastic film 31 using a second coating liquid, and a step (1) of forming a first coating layer 32 on the second coating layer 33 using a first coating liquid.

[0069] Each coating layer is obtained by applying a coating layer and drying it. The same coating liquid may be applied (reapplied) in multiple layers. The method for applying the coating liquid is not particularly limited, and known coating methods can be used, such as gravure printing, flexographic printing, brush coating, gravure coating, die coating, bar coating, spray coating, flow coating, dip coating, spin coating, curtain coating, etc. Among these, flexographic printing is preferred because of its high quality and productivity.

[0070] The drying method is not particularly limited as long as it can remove the aqueous medium contained in the applied coating liquid, 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.

[0071] <Laminate> The laminate is not limited to the above-described embodiment. For example, in the laminate 10 shown in FIG. 1, the coating layer 12 is provided over the entire surface of one side of the plastic film 11, but the coating layer 12 may also be provided over a portion of the other side of the plastic film 11. In this case, it is preferable that another coating layer is provided in the area of ​​the other side of the plastic film 11 where the coating layer 12 is not provided. Another coating layer may also be provided on the surface of the first coating layer 12 opposite the plastic film 11 side. For example, a varnish layer formed from a varnish composition may be used.

[0072] Similarly, in the laminate 20 shown in Fig. 2, the first coating layer 22 is provided over the entire surface of one side of the plastic film 21, but the first coating layer 22 may also be provided over a portion of one side of the plastic film 21. Another coating layer may be provided on the surface of the second coating layer 23 opposite to the first coating layer 22 side (visible side). For example, a varnish layer formed from a varnish composition may be used.

[0073] In the laminate 30 shown in Fig. 3, the first coating layer 32 is provided over the entire second coating layer 33, but the first coating layer 32 may also be provided over a portion of the second coating layer 33. Another coating layer may be provided on the surface of the first coating layer 32 opposite to the second coating layer 33 side (visible side). For example, a varnish layer formed from a varnish composition may be used.

[0074] <White ink for underlay> White ink is used to apply a white ink to the side of the color layer opposite the visible side to provide a white underlay (also called a white coating layer or white printing layer) in order to further improve the sharpness of images, etc. of color printing layers printed on plastic substrates.This white ink is called white underlay white ink. The white ink for underlay is preferably an ink containing an acrylic resin from the viewpoint of adhesion to the substrate and abrasion resistance. The white pigment is not particularly limited, but titanium oxide is preferred. In the reverse printing illustrated in FIG. 2, for example, a white printing layer is formed by printing a white ink for overprinting on a printing layer (color printing layer) printed with the water-based ink of the present invention. In the surface printing illustrated in FIG. 3, for example, a white ink for underlining is printed on a substrate to form a white printed layer, and then the aqueous ink of the present invention is printed thereon to form a printed layer (color printed layer). As the white ink for underlayment, a water-based ink containing the water-based liquid composition of the present invention and a white pigment can be used.

[0075] <Primer layer> 1 to 3, a primer layer may be provided on the substrate. The aqueous primer (aqueous liquid composition) of the present invention can be used as the primer composition for forming the primer layer. In the reverse printing illustrated in Figure 2, for example, the aqueous primer of the present invention is applied to a plastic substrate to form a primer layer, the aqueous ink of the present invention is printed on top of that to form a printing layer (color printing layer), and a white ink for overprinting is printed on top of that to form a white printing layer. In the surface printing illustrated in Figure 3, for example, the aqueous primer of the present invention is applied to a plastic substrate to form a primer layer, a white ink for underlining is printed on the substrate to form a white printing layer, and the aqueous ink of the present invention is printed on top of that to form a printing layer (color printing layer).

[0076] <Varnish layer> 1 to 3, a varnish layer may be provided as the uppermost layer. The aqueous varnish (aqueous liquid composition) of the present invention can be used as the varnish composition for forming the varnish layer. In the laminate illustrated in FIG. 1, for example, a color print layer is formed on a plastic substrate, and a varnish layer, which serves as the top layer, is formed thereon. In the reverse printing illustrated in FIG. 2, for example, a color print layer is formed on a plastic substrate, a white print layer is formed thereon, and a varnish layer, which serves as the top layer, is formed thereon. In the surface printing illustrated in FIG. 3, for example, a white print layer is formed on a plastic substrate, a color print layer is formed thereon, and a varnish layer, which serves as the top layer, is formed thereon. In addition, in the laminate illustrated in Figure 1, for example, a varnish layer may be formed on the surface opposite to the coating layer on the plastic substrate coated with a coating liquid containing the aqueous liquid composition of the present invention. In the reverse printing illustrated in FIG. 2, for example, a varnish layer may be formed on the surface of the plastic substrate opposite to the color print layer. In the surface printing illustrated in FIG. 3, for example, a varnish layer may be formed on the surface opposite to the white print layer on the plastic substrate.

[0077] <label> A label according to one embodiment of the present invention is obtained by using the laminate according to this embodiment described above. Label applications include various labels attached to packaging containers for beverages, seasonings, prepared foods, boxed lunches, and other food and beverage products, as well as daily necessities such as cosmetics. The labels are particularly suitable for products whose packaging containers are plastic bottles, such as labels for bottled beverages. Examples of bottled beverages include beverages, liquid seasonings (dressings, noodle soup bases, soy sauce, liquid miso paste, etc.), and cooking oils. The label may be in the form of, for example, a wrap label or a shrink label.

[0078] <Packaging material> The packaging material can be used for various products such as food, daily necessities, miscellaneous goods, and hygiene products. The shape of the packaging material is not particularly limited, and examples thereof include bottom-sealed bags, side-sealed bags, three-side-sealed bags, pillow bags, gusset bags, square-bottom bags, and stand-up bags.

[0079] According to this embodiment, as shown in the examples described later, an acrylic resin (A) having a specific acid value and an acrylic resin (B) having a specific acid value and a specific glass transition temperature are combined in a specific ratio as the binder resin, a specific solvent (C) and an aqueous medium (D) are combined as the medium so that the volatile content / C ratio is a specific ratio, and a large particle size wax (E) and a small particle size wax (F) having a specific average particle size are used in combination. This results in an aqueous liquid composition for coating plastic substrates that has excellent gloss, heat resistance, and abrasion resistance of the coating film, has good adhesion to plastic substrates, reduces plate tangling when used in flexographic printing, and also has good storage stability of the liquid and good dispersibility when a pigment is added. [Example]

[0080] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples as long as it does not depart from the gist of the invention. In the following, "NV" stands for non-volatile content (solid content). "%", which is a unit of content, means "% by mass" unless otherwise specified. "Parts" means "parts by mass" unless otherwise specified.

[0081] [Raw materials used] <Acrylic resin (A)> The following compounds were used as the acrylic resin (A) and the comparative component (A'). A-1: BASF Japan Ltd., product name "Joncryl 52J", weight average molecular weight 1,700, acid value 238 mg KOH / g, glass transition temperature 56°C, solid content 60% by mass. A-2: Seiko PMC Corporation, product name "Hi-Loss X-NL-1189", weight average molecular weight 11,000, acid value 90 mg KOH / g, glass transition temperature 28°C, solid content 29% by mass. A-3: Manufactured by BASF Japan Ltd., product name "Joncryl PDX-6157", weight average molecular weight 6,000, acid value 205 mg KOH / g, glass transition temperature 84°C, solid content 34% by mass. A'-4: Seiko PMC Corporation, product name "Hi-Loss X-AW-36H", weight average molecular weight 15,000, acid value 60 mg KOH / g, glass transition temperature 53°C, solid content 25% by mass. A'-5: Seiko PMC Corporation, product name "Hi-Loss X-UL-1191", weight average molecular weight 6,500, acid value 270 mg KOH / g, glass transition temperature 128°C, solid content 32% by mass.

[0082] <Acrylic emulsion resin (B)> The following compounds were used as the acrylic emulsion resin (B) and the comparative component (B'). B-1: BASF Japan Ltd., product name "Joncryl PDX-7777", acid value 71 mg KOH / g, glass transition temperature 40°C, solid content 46% by mass. B-2: Seiko PMC Corporation, product name "Hi-Loss XM-141", acid value 19 mg KOH / g, glass transition temperature 15°C, solid content 46% by mass. B-3: BASF Japan Ltd., product name "Joncryl PDX-7356", acid value 78 mg KOH / g, glass transition temperature 25°C, solid content 46% by mass. B-4: Manufactured by BASF Japan Ltd., product name "Joncryl PDX-7616A", acid value 30 mg KOH / g, glass transition temperature 9°C, solid content 44 mass%. B-5: Seiko PMC Corporation, product name "Hi-Loss X-QE-1042", acid value 33 mg KOH / g, glass transition temperature 53°C, solid content 41% by mass. B'-6: BASF Japan Ltd., product name "Joncryl PDX-7164", acid value 4 mg KOH / g, glass transition temperature 9°C, solid content 47% by mass. B'-7: Seiko PMC Corporation, product name "Hi-Loss X-HE-2342", acid value 125 mg KOH / g, glass transition temperature 16°C, solid content 44% by mass. B'-8: Seiko PMC Corporation, product name "Hi-Loss X-JE-1113", acid value 42 mg KOH / g, glass transition temperature -24°C, solid content 43% by mass. B'-9: Seiko PMC Corporation, product name "Hi-Loss X-NE-2186", acid value 59 mg KOH / g, glass transition temperature 107°C, solid content 52% by mass.

[0083] <Comparative resin> Urethane dispersion: Mitsui Chemicals, Inc., product name "Takelac W-6061", solid content 30% by mass.

[0084] <Solvent (C)> C-1: Propylene glycol, boiling point 188.2°C, flash point 99°C, solid content 0% by mass. · C-2: Dipropylene glycol, boiling point 231.8°C, flash point 138°C, solid content 0% by mass. · C-3: Methylpropylene glycol, boiling point 121°C, flash point 32°C, solid content 0% by mass.

[0085] <Large particle wax (E)> E-1: Mitsui Chemicals, Inc., product name "W-500", average particle size 2.5 μm, penetration 10, solid content 40% by mass. <Small particle size wax (F)> F-1: Mitsui Chemicals, Inc., product name "W-700", average particle size 1 μm, penetration less than 1, solid content 40% by mass. <Pigments> Pigment: Pigment Blue 15:3 (manufactured by BASF Japan Ltd., product name "Heliogen Blue D7088", solid content 100% by mass). Titanium oxide: Pigment White 6 (manufactured by Ishihara Sangyo Kaisha, Ltd., product name "CR-90", solid content 100% by mass) <Optional ingredients> Antifoaming agent: BYK-Chemie Japan Co., Ltd., product name "BYK-094", solid content 96% by mass. Curing agent: Carbodiimide curing agent (manufactured by Nisshinbo Chemical Inc., product name "Carbodilite E-02", non-volatile content 40% by mass)

[0086] [Evaluation method] <Dispersibility> The dispersibility of the pigment-containing water-based ink was evaluated by the following method. According to the composition shown in the table, acrylic resin (A), acrylic emulsion resin (B), solvent (C), aqueous medium (D), large particle wax (E), small particle wax (F), pigment, and other optional ingredients were mixed and dispersed using a bead mill (manufactured by Shinmaru Enterprises Co., Ltd., product name "Dynomill", using glass beads) to obtain an aqueous ink. The obtained aqueous ink was applied (thinly spread) on a plastic substrate, and the formed coating film (drawn product) was visually inspected and evaluated according to the following criteria. ◯: Dispersion treatment is possible using a bead mill, and the color development of the resulting water-based ink is good. △: Dispersion processing is possible using a bead mill, but the color development of the resulting water-based ink is insufficient (in the case of blue pigment, the coating film is whitish, and in the case of titanium oxide, the coating film has low gloss). ×: The dispersion liquid does not pass through the bead mill, causing clogging inside the Dyno Mill.

[0087] <Storage stability> The storage stability of the aqueous ink (or aqueous liquid composition when no pigment was blended) was evaluated using the following method. The aqueous ink obtained by the dispersion treatment was placed in a 250 ml plastic container and stored in an environment of 40°C for one month. After storage, the condition of the aqueous ink was visually inspected and evaluated according to the following evaluation criteria. ○: No change from the state before storage for one month. △: The viscosity has increased slightly compared to before storage for one month, but there is no change in appearance. ×: Viscosity has increased significantly or aggregates have formed compared to before storage for one month.

[0088] The printed layer formed by printing an aqueous ink (or an aqueous liquid composition when no pigment was added) on a plastic substrate was evaluated for gloss, plate entanglement reduction, adhesion, heat resistance, and abrasion resistance using the methods described below. <Glossiness> A gloss meter (BYK Gardner, product name "micro-TRI-gloss") was used to measure the 60° gloss (60° specular gloss) of the surface on the printed layer side, and the gloss of the printed layer was evaluated according to the following criteria: The higher the 60° gloss, the better the gloss. ○: 60° gloss is 70% or more. △: 60° gloss is 60% or more but less than 70%. ×: 60° gloss is less than 60%.

[0089] <Reduced plate entanglement> The aqueous ink obtained in each example (aqueous liquid composition when no pigment was blended) was used for printing in the following manner. Using a CI-type flexographic printing press (KBA-Flexotecnica), a print was made on the treated surface of a commercially available OPP film (Toyobo Co., Ltd., product name "Pylen P2161", thickness 20 μm) at a speed of 80 m / min for 10 minutes. The anilox roll was 1000 LPI, 4 cc / m 2 The drying conditions for the printed layer were an intercolor dryer at 90°C and a tunnel dryer at 90°C. The 5% halftone dot area of ​​the resulting print was visually observed, and the plate entanglement reduction ability was evaluated according to the following evaluation criteria. ◯: No thickening of the 5% halftone dots is observed, or some thickening is observed but the halftone dots are not connected to each other. △: 5% thickening of the dots is observed, and the dots are slightly connected to each other. ×: 5% The shape of the halftone dots is distorted and the halftone dots are clearly connected to each other.

[0090] <Adhesion> An 18 mm wide piece of cellophane tape (manufactured by Nichiban Co., Ltd.) was applied to the printed surface of the laminate obtained in each example and pressed with a finger, after which the cellophane tape was quickly peeled off and the condition of the printed layer remaining on the plastic substrate was visually inspected and evaluated according to the following evaluation criteria. ○: The ratio of the area of ​​the peeled printed layer to the adhesive area of ​​the cellophane tape (peeling ratio) was more than 0% and less than 10%. △: The ratio of the area of ​​the peeled printed layer to the adhesive area of ​​the cellophane tape (peeling ratio) was 10% or more and less than 30%. ×: The ratio of the area of ​​the peeled printed layer to the adhesive area of ​​the cellophane tape (peeling ratio) is 30% or more.

[0091] <Heat resistance> The glossy side of aluminum foil was placed on the printed surface of the laminate obtained in each example, and a load of 90°C and 0.2 MPa was applied for 1 second using a heat seal tester (manufactured by Tester Sangyo Co., Ltd.). The laminate was then peeled off by hand, and the presence or absence of peel resistance and the state of fusion of the printed layer were visually confirmed and evaluated according to the following criteria. ◯: There is no peel resistance and the printed layer is not fused. △: Weak peel resistance, no fusion of the printed layer. ×: Peel resistance observed, printed layer fused.

[0092] <Abrasion resistance> A cloth (No. 3 gold cloth) soaked in water was placed on the printed surface of the laminate obtained in each example, and rubbed 100 times back and forth under a load of 200 gf using a Gakushin-type rub fastness tester (manufactured by Tester Sangyo Co., Ltd.) The condition of the printed layer after rubbing was visually inspected, and the degree of peeling of the printed layer was evaluated according to the following criteria. ○: The loss of the printed layer was more than 0% and less than 10% of the friction area. △: The printed layer fell off in an area of ​​10% or more but less than 30% of the friction area. ×: The printed layer fell off in 30% or more of the friction area.

[0093] <Examples 1 to 44> Examples 1 to 26 are working examples, and Examples 27 to 44 are comparative examples. Examples 1 to 25 and 27 to 44 are examples in which aqueous inks containing an aqueous liquid composition and a pigment were prepared, while Example 26 is an example in which an aqueous liquid composition containing no pigment was prepared as the aqueous medium.

[0094] A water-based ink was obtained by mixing acrylic resin (A), acrylic emulsion resin (B), solvent (C), water (D), large particle size wax (E), small particle size wax (F), antifoaming agent, and pigment according to the formulation shown in the table. When no pigment was added, an aqueous medium was prepared by mixing acrylic resin (A), acrylic emulsion resin (B), solvent (C), water (D), large particle size wax (E), small particle size wax (F), and antifoaming agent according to the formulation shown in the table. The resulting aqueous ink or aqueous medium was used as a coating liquid to produce a laminate by the following method.

[0095] (Example of laminate manufacturing) An OPP film (manufactured by Toyobo Co., Ltd., product name "Pylen P2161", thickness 20 μm) was used as the plastic substrate. Cell volume 10.0cm 3 / m 2 A flexographic hand proofer equipped with an anilox roll of 1.0 g / m was used as an applicator, and the coating liquid of each example was applied to one side of the plastic substrate so that the coating amount after drying was 2.0 g / m. 2 The coating (printing) was then carried out by drying with hot air from a dryer for 1 minute to form a printed layer (coating film), thereby obtaining a laminate (printed product). When the coating liquid was an aqueous ink, a blue or white printed layer was obtained, and when the coating liquid was an aqueous medium, a nearly transparent or very thin white printed layer was obtained.

[0096] (evaluation) The dispersibility of the aqueous ink was evaluated using the method described above. The storage stability of the aqueous ink or aqueous medium was evaluated using the method described above. The printed layer of the laminate was evaluated for each item shown in the table using the method described above. 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 content (solid content) of each component (unit: mass%). It was confirmed that the flash points of the aqueous liquid compositions of Examples 1 to 44 were above 60°C.

[0097] [Table 1]

[0098] [Table 2]

[0099]

Table 3

[0100]

Table 4

[0101]

Table 5

[0102]

Table 6

[0103]

Table 7

[0104]

Table 8

[0105]

Table 9

[0106]

Table 10

[0107]

Table 11

[0108]

Table 12

[0109] [Table 13]

[0110] [Table 14]

[0111] As shown in the results in the table, in Examples 1 to 26, the aqueous liquid compositions and aqueous inks obtained had excellent coating film gloss, heat resistance, and abrasion resistance, and also had good adhesion to plastic substrates, reduced plate entanglement when used in flexographic printing, and also had good storage stability of the liquid and good dispersibility when a pigment was blended.

[0112] In Example 26, which is an example of an aqueous liquid composition containing no pigment, when B / A was set to less than 0.25, a similar tendency to that in Comparative Example 35 was observed. In addition, in Example 26, when volatile content / C was set to more than 20, a similar tendency to that in Comparative Example 38 was observed.

[0113] (Application example 1) In the laminate production example, a white printed layer was provided between the substrate and the printed layer, and a varnish layer (top layer) was further provided on the visible side of the printed layer to form a laminate. (Application example 2) In the laminate production example, a white printed layer was provided on the visible side of the printed layer, and a varnish layer (top layer) was further provided on the visible side of the white printed layer to form a laminate. In Application Examples 1 and 2, the white print layer was formed using the aqueous ink of Example 24, and the varnish layer was formed using the aqueous liquid composition of Example 26. The laminates obtained in Application Examples 1 and 2 were also evaluated to be excellent, similar to Examples 1 to 26. [Explanation of symbols]

[0114] 10, 20, 30 laminates 11, 21, 31 Plastic film (plastic substrate) 12 Coating layer 22, 32 First coating layer 23, 33 Second coating layer

Claims

1. An aqueous liquid composition used for coating a plastic substrate, an acrylic resin (A) having an acid value of 80 mgKOH / g or more and 260 mgKOH / g or less; an acrylic emulsion resin (B) having an acid value of 10 mgKOH / g or more and less than 80 mgKOH / g and a glass transition temperature of 0 to 60°C; a solvent (C) represented by the following formula (c1); an aqueous medium (D) (excluding the solvent (C)); a large particle size wax (E) having an average particle size of 1.5 μm or more; and a small particle size wax (F) having an average particle size of less than 1.5 μm, the content of the solid content of the acrylic resin (A) is 8.2 to 60 mass% and the content of the solid content of the acrylic emulsion resin (B) is 20 to 82 mass% relative to the total mass of the solid content of the aqueous liquid composition; B / A, which represents a mass ratio of the solid content of the acrylic emulsion resin (B) to the solid content of the acrylic resin (A), is 0.25 / 1 to 10 / 1; The aqueous liquid composition for coating a plastic substrate has a mass ratio of total volatile matter to the solvent (C), volatile matter / C, of ​​3 / 1 to 20 / 1. R １ -O-(AO)n-R ２ (c1) (R in the formula １ , R ２ are each independently a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, and R １ and R ２ may be the same or different, A is a linear or branched alkylene group having 2 to 4 carbon atoms, n is an integer of 1 to 6, and when n is 2 or more, the n As may be the same or different.

2. 2. The aqueous liquid composition according to claim 1, wherein the acrylic resin (A) has a weight average molecular weight of 2,000 to 20,000.

3. The aqueous liquid composition according to claim 1, wherein the solvent (C) has a flash point of 0 to 140°C.

4. 2. The aqueous liquid composition according to claim 1, having a flash point of greater than 60°C.

5. The aqueous liquid composition according to claim 1, wherein the total mass of the solid content of the aqueous liquid composition is 10 to 40 mass% relative to the total mass of the aqueous liquid composition.

6. The boiling point of the solvent (C) is 170 to 250 ° C., and the content of the solvent (C) is 1 to 22 mass% with respect to the total mass of the aqueous liquid composition. The aqueous liquid composition according to claim 1.

7. The aqueous liquid composition according to claim 1, wherein the solvent (C) comprises at least one selected from the group consisting of alkylene glycols, dialkylene glycols, monoalkylene glycol monoalkyl ethers, and dialkylene glycol monoalkyl ethers.

8. the large particle size wax (E) has an average particle size of 1.5 μm or more and 5 μm or less and a penetration of 7 to 12; 2. The aqueous liquid composition according to claim 1, wherein the small particle size wax (F) has an average particle size of 0.4 μm or more and less than 1.5 μm and a needle penetration of 0.3 to 7.

9. The aqueous liquid composition according to claim 1, wherein the total content of the solid content of the large particle size wax (E) and the solid content of the small particle size wax (F) is 1 to 20 mass% relative to the total mass of the solid content in the aqueous liquid composition.

10. The aqueous liquid composition according to claim 1, wherein C / (E+F), which represents the mass ratio of the content of the solvent (C) to the total content of the solids of the large particle wax (E) and the small particle wax (F), is 0.5 / 1 to 15 / 1.

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

12. The aqueous liquid composition according to claim 1, which is used for one or more selected from an aqueous varnish, an aqueous medium, and an aqueous primer.

13. A water-based ink comprising the aqueous liquid composition according to claim 1 and a pigment.

14. A laminate comprising a printed layer formed by printing the water-based ink according to claim 13 on a plastic substrate.

15. The laminate according to claim 14, further comprising a white printed layer formed on the printed layer by printing a white ink for whitening.

16. A laminate comprising a white printed layer formed by printing an underlay white ink on a plastic substrate, and a printed layer formed by printing the water-based ink according to claim 13 on the white printed layer.

17. 14. A laminate comprising: a primer layer formed on a plastic substrate by applying an aqueous primer comprising the aqueous liquid composition according to claim 1; a printed layer formed on the primer layer by printing the aqueous ink according to claim 13; and a white printed layer formed on the printed layer by printing a white ink for underlining.

18. A laminate comprising: a primer layer formed on a plastic substrate by applying an aqueous primer comprising the aqueous liquid composition according to claim 1; a white printed layer formed on the primer layer by printing a white ink for undercoating; and a printed layer formed on the white printed layer by printing the aqueous ink according to claim 13.

19. A laminate according to any one of claims 14 to 18, having as its uppermost layer a varnish layer formed by applying an aqueous varnish made from the aqueous liquid composition according to claim 1.

20. The laminate according to claim 14, wherein the printed layer has a 60-degree specular gloss of 70% or more.

21. A laminate comprising a plastic substrate, one or both of a primer layer containing no pigment and provided in contact with the plastic substrate, and a varnish layer containing no pigment and provided as the top layer, and a printed layer containing a pigment, and at least one of the primer layer, the varnish layer, and the printed layer containing the pigment is a layer formed by applying a coating liquid containing the aqueous liquid composition described in claim 1.

22. The laminate according to claim 21, wherein a layer formed by applying a coating liquid containing the aqueous liquid composition has a 60 degree specular gloss of 70% or more.

23. A label or packaging material obtainable using the laminate according to any one of claims 14 to 22.

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