Aqueous resin composition, aqueous coating liquid for plastic film, and laminate

Abstract

The present invention provides an aqueous resin composition that can be suitably used for an aqueous coating solution capable of forming a coating layer that has excellent substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, as well as transparency. [Solution] This aqueous resin composition is used in an aqueous coating solution that produces a coating film with a haze value of 15% or less. The aqueous resin composition contains an emulsion of polyolefin resin (polyolefin resin emulsion) having a melting point of 60 to 97°C and an acid value of 13 to 60 mgKOH / g, as well as a polyethylene wax and / or paraffin wax. Based on the mass of the solids in the aqueous resin composition, the polyolefin resin content is 60 to 95 mass% and the wax content is 4 to 25 mass%, with the mass ratio of polyolefin resin:wax being 1:0.043 to 1:0.300.

Description

[Technical Field]

[0001] The present invention relates to an aqueous resin composition, an aqueous coating liquid, and a laminate. [Background technology]

[0002] Plastic and other resin containers, packaging materials, and labels are lightweight, durable, and easily mass-produced, making them indispensable in a variety of fields, including food, cosmetics, and daily necessities. For example, biaxially oriented polypropylene (OPP) is a glossy, moisture-resistant, and transparent material used in packaging films for vegetables and fruits, and the transparent windows in paper craft packs. Polyethylene terephthalate (PET) is also highly transparent, allowing for a clear view of the contents, making it widely used in food packaging for salads, prepared dishes, sushi, sashimi, and other foods. Polystyrene (PS) is another general-purpose resin, and its transparency is utilized in a variety of applications, including small food containers, dessert cups, and DVD cases.

[0003] Furthermore, from the viewpoint of protecting the global environment, there is a growing demand for water-based inks used in printing on the above-mentioned resin containers and packaging materials, which emit less organic solvents during printing and leave less solvent remaining in the printed material.

[0004] Various proposals have been made to improve the physical properties of aqueous inks, including aqueous inks themselves, aqueous pigment dispersions for incorporation into aqueous inks, and aqueous varnish compositions. For example, a water-based printing ink composition for lamination has been proposed, which prevents the printed water-based ink from adhering to the laminated surface when the printed surface is laminated to impart durability and moisture resistance after printing on paper containers, packaging paper, craft tape, etc. (Patent Document 1). Another proposal has been made of an aqueous pigment ink for inkjet textile printing, which has excellent wet rub fastness and can be used to print on substrates such as plain paper, coated paper, and specialty paper, as well as fabrics, wood substrates, metal substrates, glass substrates, and plastic substrates (Patent Document 2). Other proposals include an aqueous pigment dispersion that can achieve both gloss and lightfastness in an inkjet printing ink, and an inkjet printing ink using the aqueous pigment dispersion (Patent Document 3). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-140497 [Patent Document 2] International Publication No. 2020 / 090212 [Patent Document 3] Patent Publication No. 2021-31616 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, in order to improve the various physical properties of aqueous inks, aqueous inks and additives to be contained in aqueous inks have long been studied. The present inventors investigated forming a printed layer using the aqueous ink composition proposed in Patent Document 1, the aqueous pigment ink proposed in Patent Document 2, the inkjet printing ink proposed in Patent Document 3, and the like. As a result, it was found that printed layers formed using the above-mentioned conventional inks were not good in at least one of properties such as adhesion to the substrate (hereinafter referred to as "substrate adhesion"), blocking resistance, heat resistance, scratch resistance, and transparency, and that there was still room for improvement.

[0007] On the other hand, in packaging materials such as shrink labels, a hot melt adhesive is often applied to a film on which an ink-printed layer is provided. Therefore, in order to make an ink suitable for such applications, it is also required that when the hot melt adhesive is applied, a printed layer can be formed that can exhibit appropriate adhesive properties due to the hot melt adhesive (hereinafter, this property will be referred to as "hot melt adhesive properties").

[0008] Therefore, the present invention aims to provide an aqueous resin composition that can be suitably used for an aqueous coating solution capable of forming a coating layer that has good substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, as well as transparency. [Means for solving the problem]

[0009] That is, the present invention provides an aqueous resin composition used for an aqueous coating solution having a coating film haze value of 15% or less, the aqueous resin composition comprising a resin emulsion and a wax, wherein the resin emulsion comprises a polyolefin resin emulsion containing a polyolefin resin having a melting point of 60 to 97°C and an acid value of 13 to 60 mgKOH / g, the wax comprising at least one wax selected from the group consisting of polyethylene-based waxes and paraffin-based waxes, the content of the polyolefin resin being 60 to 95 mass% and the content of the wax being 4 to 25 mass% relative to the mass of the solids content of the aqueous resin composition, and the mass ratio of the content of the wax to the content of the polyolefin resin being polyolefin resin:wax=1:0.043 to 1:0.300. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide an aqueous resin composition that can be suitably used for an aqueous coating solution capable of forming a coating layer that has excellent substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, as well as transparency. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view schematically showing an example of the arrangement of layers constituting a laminate according to one embodiment of the present invention. [Figure 2] FIG. 3 is a cross-sectional view schematically showing another example of the arrangement of layers constituting the laminate of one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0013] In this disclosure, the term "aqueous" in "aqueous resin composition" and "aqueous coating liquid" refers to the inclusion of an aqueous medium. "Aqueous medium" refers to a liquid medium containing at least water. "Liquid medium" refers to water and volatilizable liquids such as organic solvents. "Volatile content" refers to volatilizable components, such as water and organic solvents, contained in the aqueous resin composition or aqueous coating liquid. Specifically, the heating residue obtained by a measurement method conforming to JIS K 5601-1-2:2008 is defined as the solid content (also referred to as the non-volatile content), and the remaining content is defined as the volatile content. "Coating layer" refers to a layer formed by applying an aqueous resin composition or an aqueous coating liquid using the aqueous resin composition by printing, coating, or the like, and volatilizing the volatile content in the aqueous resin composition or aqueous coating liquid.

[0014] In the present disclosure, the term "aqueous resin composition" refers to a composition used in an aqueous coating solution (a resin composition for aqueous coating solutions). The aqueous coating solution refers to a liquid material to be applied to a substrate and is obtained using an aqueous resin composition. Specifically, depending on the type, application, and coating method of the aqueous coating solution, an aqueous coating solution can be prepared by adding appropriate additives to the aqueous resin composition or by adding a liquid medium to adjust the viscosity to an appropriate level. Examples of aqueous coating solutions include aqueous inks, aqueous varnishes, aqueous mediums, aqueous primers, and aqueous reducers. For example, when preparing an aqueous ink as the aqueous coating solution, the aqueous ink can be prepared using a resin composition for aqueous inks in which a colorant (pigment and / or dye) is added to the aqueous resin composition. In the present disclosure, a composition in which a colorant is added to the aqueous resin composition may be referred to as a "resin composition for aqueous inks." Therefore, in the case of the above-mentioned resin composition for aqueous ink, the content (mass%) of component A relative to the solid content of the aqueous resin composition in the present disclosure can be defined as the content (mass%) of component A relative to the mass of the solid content (excluding colorant) of the resin composition for aqueous ink.

[0015] In this disclosure, "acrylic resin" refers to a polymer containing a monomer unit 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." The symbol "to" indicating a numerical range means that the numerical values ​​before and after it are included as the lower and upper limits. The lower and upper limits of the numerical ranges in this disclosure can be arbitrarily combined to form a new numerical range.

[0016] The present inventors have investigated aqueous resin compositions for aqueous coating solutions that can form transparent coating layers with excellent substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance. Specifically, they conducted experiments and studies using aqueous resin compositions containing a resin emulsion and a wax. As a result, they found that the desired aqueous resin composition can be obtained by incorporating a polyolefin resin emulsion containing a polyolefin resin having a melting point and acid value within a specific range and a specific wax in a specific amount and mass ratio relative to the mass of the solids of the aqueous resin composition.

[0017] <Aqueous resin composition> An aqueous resin composition according to one embodiment of the present invention (sometimes simply referred to as "aqueous resin composition" in the present disclosure) is a composition used in an aqueous coating solution that produces a coating film with a haze value of 15% or less. This aqueous resin composition contains a resin emulsion and a wax. The resin emulsion contains a polyolefin resin emulsion containing a polyolefin resin having a melting point of 60 to 97°C and an acid value of 13 to 60 mgKOH / g. The wax contains at least one wax selected from the group consisting of polyethylene waxes and paraffin waxes. The aqueous resin composition contains 60 to 95% by mass of the polyolefin resin and 4 to 25% by mass of the wax relative to the mass of the solids. The mass ratio of the wax to the polyolefin resin is polyolefin resin:wax = 1:0.043 to 1:0.300.

[0018] By using the aqueous resin composition having the above-described configuration, it is possible to obtain an aqueous coating solution capable of forming a coating layer that has excellent substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, as well as transparency.

[0019] Specifically, a coating layer having transparency has a haze value of 15% or less. Preferably, the haze value is 10% or less. The haze value is determined by measuring the haze values ​​(=measured value-haze value of substrate) at three points on a coating film formed by applying an aqueous coating liquid containing an aqueous resin composition onto a plastic film substrate by flexographic printing or gravure printing at room temperature (25°C) using a haze computer (trade name "H2-2P", manufactured by Suga Test Instruments Co., Ltd.), and calculating the average of these values.

[0020] Furthermore, as a coating layer with good scratch resistance, specifically, an aqueous resin composition having excellent scratch resistance can be provided, in which a coating film obtained by applying an aqueous coating liquid containing the aqueous resin composition is rubbed widthwise with a hard object, and after 10 strokes, the ratio of the area of ​​the coating film that has fallen off to the test area of ​​the coating film is less than 20%. Below, preferred configurations of the aqueous resin composition will be described, mainly from the viewpoint of facilitating the production of a coating layer having the above-mentioned properties.

[0021] [Resin emulsion] The aqueous resin composition contains a resin emulsion. The resin, which is a dispersoid (solid content) dispersed in the dispersion medium (aqueous medium) in the resin emulsion, is a component that constitutes the solid content of the aqueous resin composition. The resin emulsion contains at least a polyolefin resin emulsion containing a specific polyolefin resin described below. In addition to the specific polyolefin resin emulsion described below, the aqueous resin composition may also contain other polyolefin resin emulsions (other polyolefin resin emulsions), an acrylic resin emulsion described below, and a urethane resin emulsion.

[0022] (Polyolefin resin emulsion) The aqueous resin composition contains a polyolefin resin emulsion. This polyolefin resin emulsion is an emulsion of a polyolefin resin having a melting point of 60 to 97°C and an acid value of 13 to 60 mgKOH / g. This specific polyolefin resin and its emulsion may be simply referred to as a "polyolefin resin" and a "polyolefin resin emulsion," respectively. The polyolefin resin emulsion is an emulsion formed by colloidal dispersion of a polyolefin resin in an aqueous resin composition. Use of this specific polyolefin resin emulsion contributes to the formation of a coating layer that has excellent substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, and is also transparent.

[0023] The melting point of the polyolefin resin is 60 to 97°C. Using a polyolefin resin with a melting point within this range contributes to the formation of a coating layer with excellent substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance. If the melting point of the polyolefin resin is less than 60°C, the coating layer will have poor blocking resistance and heat seal blocking resistance, and will also have insufficient substrate adhesion, hot melt adhesive properties, and scratch resistance. On the other hand, if the melting point of the polyolefin resin exceeds 97°C, the coating layer will have poor substrate adhesion and scratch resistance on an OPP substrate. The melting point of the polyolefin resin is preferably 63 to 90°C, and more preferably 67 to 80°C, from the viewpoint of easily obtaining a coating layer with even better substrate adhesion, blocking resistance, heat seal blocking resistance, and scratch resistance. The melting point of the polyolefin resin can be measured by differential scanning calorimetry (DSC).

[0024] The acid value of the polyolefin resin is 13 to 60 mgKOH / g. Using a polyolefin resin with an acid value within this range contributes to the formation of a coating layer with excellent substrate adhesion, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, and also improves the storage stability of the aqueous resin composition. If the acid value of the polyolefin resin is less than 13 mgKOH / g, the coating layer will have poor substrate adhesion, hot melt adhesive properties, and scratch resistance. On the other hand, if the acid value of the polyolefin resin exceeds 60 mgKOH / g, the storage stability of the aqueous resin composition, substrate adhesion to PET and PS substrates, heat seal blocking resistance to PET substrates, hot melt adhesive properties to PET substrates, and scratch resistance to PET and PS substrates will be poor. The acid value of the polyolefin resin is preferably 14 to 55 mgKOH / g, and more preferably 16 to 45 mgKOH / g from the viewpoint of easily obtaining a coating layer with better substrate adhesion, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance. The acid value of the polyolefin resin is the amount of potassium hydroxide, expressed in milligrams, required to neutralize acid groups such as carboxy groups per gram of sample solid content, and is measured in accordance with JIS K 5601-2-1:1999.

[0025] The content of polyolefin resin, which is the solid content of the polyolefin resin emulsion in the aqueous resin composition, is 60 to 95% by mass based on the mass of the solid content of the aqueous resin composition. If the content of polyolefin resin is less than 60% by mass relative to the mass of the solid content of the aqueous resin composition, the coating layer will have poor substrate adhesion, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, and will not have sufficient transparency. On the other hand, if the content of polyolefin resin is more than 95% by mass relative to the mass of the solid content of the aqueous resin composition, the coating layer will have poor blocking resistance, heat seal blocking resistance, and scratch resistance. By setting the content of polyolefin resin to 60 to 95% by mass relative to the mass of the solid content of the aqueous resin composition, it is possible to contribute to the formation of a coating layer that has good substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, and that is also transparent. The content of the polyolefin resin relative to the mass of the solid content of the aqueous resin composition is preferably 65 to 92 mass % from the viewpoints of improving substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, scratch resistance, and transparency.

[0026] Specific examples of polyolefin resins include polyethylene (PE), polypropylene (PP), polybutylene, polybutene, hydrogenated polybutene, polyisobutylene, hydrogenated polyisobutylene, and olefin copolymers. These may be used alone or in combination of two or more. Examples of polyethylene include low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and linear low-density polyethylene (LLDPE). Examples of polypropylene include atactic polypropylene, isotactic polypropylene, syndiotactic polypropylene, oxidized polypropylene, chlorinated polypropylene, crosslinked polypropylene, and modified polypropylene. Examples of olefin copolymers include ethylene-vinyl acetate copolymers, ionomer resins, ethylene-acrylic acid copolymers, ethylene-methyl acrylate copolymers, ethylene-methacrylic acid copolymers, ethylene-propylene copolymers, ethylene-α-olefin copolymers, propylene-α-olefin copolymers, and polypropylene-polyethylene copolymers, as well as olefin copolymers obtained by copolymerizing two or more of ethylene, propylene, and butylene. The various polyolefin resins listed above may also be modified polyolefin resins in which amino groups, carboxy groups, hydroxy groups, acryloyl groups, or polymer chains have been introduced into the polyolefin chain; oxidized polyolefin resins in which a portion of the polyolefin chain has been oxidized; and halogenated polyolefin resins in which a portion of the polyolefin chain has been treated with a halogen.

[0027] The aqueous resin composition uses an emulsion of the polyolefin resin listed above. The polyolefin resin emulsion may be an emulsion of a resin obtained using raw materials obtained from fossil fuels, or may be an emulsion of a resin obtained from raw materials derived from biomass. The polyolefin resin emulsion may be one produced according to a conventional method, or a commercially available product may be used. Among polyolefin resin emulsions, at least one selected from the group consisting of polypropylene resin emulsion, polyethylene resin emulsion, and polypropylene-polyethylene copolymer resin emulsion is preferred. In other words, the polyolefin resin preferably contains at least one selected from the group consisting of polypropylene resin, polyethylene resin, and polypropylene-polyethylene copolymer.

[0028] The polypropylene resin emulsion is an emulsion formed by colloidal dispersion of a polypropylene resin in an aqueous resin composition. The aqueous resin composition may contain the polypropylene resin emulsion alone or in combination with other polyolefin resin emulsions, such as a polyethylene resin emulsion or a polypropylene-polyethylene copolymer resin emulsion, which will be described later.

[0029] The polyethylene resin emulsion is an emulsion formed by colloidal dispersion of polyethylene resin in an aqueous resin composition. The aqueous resin composition may contain the polyethylene resin emulsion alone or in combination with other polyolefin resin emulsions, such as the polypropylene resin emulsion described above or the polypropylene-polyethylene copolymer resin emulsion described below.

[0030] A polypropylene-polyethylene copolymer resin emulsion is an emulsion formed by colloidal dispersion of a polypropylene-polyethylene copolymer resin in an aqueous resin composition. The arrangement of monomer units in the polypropylene-polyethylene copolymer is not particularly limited, and may be any of a block copolymer, an alternating copolymer, a random copolymer, and a graft copolymer. In the aqueous resin composition, the polypropylene-polyethylene copolymer resin emulsion may be used alone or in combination with other polyolefin resin emulsions, such as the above-mentioned polypropylene resin emulsions or polyethylene resin emulsions.

[0031] Examples of commercially available polyolefin resin emulsions include the "Arrowbase" series (manufactured by Unitika Ltd.), the "Auroren" series (manufactured by Nippon Paper Industries Co., Ltd.), and the "Aptlock" series (manufactured by Mitsubishi Chemical Corporation).

[0032] (acrylic resin emulsion) The aqueous resin composition may further contain an acrylic resin emulsion, if necessary. The acrylic resin emulsion is a type of water-dispersible acrylic resin, and for example, an emulsion-type acrylic resin having a core-shell structure can be used. The core-shell acrylic resin emulsion is configured such that the core portion contains a hydrophobic acrylic resin with a relatively high molecular weight, and the shell portion contains a hydrophilic acrylic resin with a relatively low molecular weight. The core portion and the shell portion may be bonded by a crosslinking agent.

[0033] By incorporating an acrylic resin emulsion into the aqueous resin composition along with the polyolefin resin emulsion, a coating layer with improved blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance is more likely to be obtained. From this perspective, the acrylic resin emulsion preferably contains an acrylic resin having a glass transition temperature (sometimes abbreviated as "Tg" in this disclosure) of 75°C or higher. The glass transition temperature of the acrylic resin is more preferably 80°C or higher and preferably 140°C or lower. The glass transition temperature of the acrylic resin is measured in accordance with JIS K 7121 as follows. Using a differential scanning calorimeter, the glass transition temperature is determined from the intersection of the baseline and the tangent to the endothermic curve in the DSC curve obtained by heating 10 mg of the acrylic resin emulsion from -100°C to 160°C at a temperature of 20°C / min.

[0034] When an acrylic resin emulsion containing an acrylic resin having a glass transition temperature of 75°C or higher is added to an aqueous resin composition, the content of the acrylic resin in the aqueous resin composition is preferably lower than the content of the polyolefin resin. Specifically, the content of the acrylic resin in the aqueous resin composition is preferably 35% by mass or less, more preferably 32% by mass or less, and preferably 10% by mass or more, relative to the content of the polyolefin resin. By adding the acrylic resin emulsion to the aqueous resin composition at the above-mentioned specific ratio relative to the content of the polyolefin resin, a coating layer having even better blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance is easily obtained. The above mass ratio can be calculated by {acrylic resin content / polyolefin resin content} × 100, based on the total mass of the aqueous resin composition, or {acrylic resin content / polyolefin resin content} × 100, based on the mass of the solids content of the aqueous resin composition.

[0035] The acrylic resin in the acrylic resin emulsion is obtained by polymerizing a monomer component containing (meth)acrylate and, if necessary, a monomer other than (meth)acrylate. When producing an acrylic resin having an acid value, it is preferable to use an unsaturated carboxylic acid as the monomer other than (meth)acrylate. The polymerization method is not particularly limited, but examples include methods in which the monomer component is polymerized by solution polymerization, bulk polymerization, emulsion polymerization, etc. in the presence of a known radical polymerization initiator. Among these, emulsion polymerization is preferred. Emulsion polymerization is a method in which the monomer component is polymerized in an aqueous medium in the presence of an emulsifier. The acrylic resin emulsion may be produced by separately producing a core portion and a shell portion and then combining them. Alternatively, it may be produced by multi-stage emulsion polymerization. The acrylic resin emulsion may be a self-crosslinking type.

[0036] Commercially available acrylic resin emulsions may be used. Examples of commercially available acrylic resin emulsions include those manufactured by Seiko PMC Corporation under the trade names "Hi-Loss XE-JE-1056," "Hi-Loss X-KE-1148," "Hi-Loss XJ-140A," "Hi-Loss X-ME-2039," "Hi-Loss X-PE-2109," and "Hi-Loss X-PE-1126"; those manufactured by Covestro Coating Resins under the trade names "Neocryl XK-110," "Neocryl A-662," and "Neocryl XK-12"; and those manufactured by BASF Japan under the trade names "Joncryl PDX-7734," "Joncryl PDX-7158," and "Joncryl PDX-7630A." One type of acrylic resin emulsion may be used alone, or two or more types may be used in combination.

[0037] (urethane resin emulsion) The aqueous resin composition may further contain a urethane resin emulsion, if necessary. By incorporating a urethane resin emulsion into the aqueous resin composition together with the polyolefin resin emulsion described above, a coating layer with better substrate adhesion and lamination suitability is more easily obtained. The urethane resin emulsion is a type of water-dispersible urethane resin, and for example, an emulsion-type urethane resin having a core-shell structure can be used. A core-shell urethane resin emulsion is composed of a core containing a relatively high-molecular-weight hydrophobic urethane resin and a shell containing a relatively low-molecular-weight hydrophilic urethane resin. The core and shell may be bonded by a crosslinking agent. By incorporating a urethane resin emulsion into the aqueous resin composition together with the polyolefin resin emulsion described above, a coating layer with improved dry laminate strength is more easily obtained. Dry laminate strength refers to the adhesive strength between the coating layer and the film in a laminate (laminate film) obtained by a dry lamination method in which a film such as a sealant film is pressure-laminated onto a coating layer provided on a substrate via an adhesive layer.

[0038] The dry laminate strength between a substrate (a second substrate described below) and a coating layer formed by applying an aqueous coating liquid using an aqueous resin composition to a substrate (a first substrate described below) via an adhesive layer is preferably 0.8 to 2.0 N / 15 mm. By setting the dry laminate strength within the above range, a laminate that does not easily peel can be obtained. From this perspective, the dry laminate strength is more preferably 1.2 to 2.0 N / 15 mm.

[0039] From the viewpoint of more easily increasing the dry laminate strength described above, the urethane resin emulsion preferably contains a urethane resin with a glass transition temperature of 30 to 120°C. The glass transition temperature of the urethane resin is more preferably 40 to 110°C, and even more preferably 50 to 100°C. The glass transition temperature of the urethane resin is measured in accordance with JIS K 7121 as follows. Using a differential scanning calorimeter, 10 mg of the urethane resin emulsion is heated from -100°C to 160°C at a rate of 20°C / min to obtain a DSC curve, and the glass transition temperature is determined from the intersection of the baseline and the tangent to the endothermic curve.

[0040] When the aqueous resin composition contains a urethane resin emulsion, the content of the urethane resin in the aqueous resin composition is preferably 55% by mass or less, more preferably 53% by mass or less, and preferably 20% by mass or more, relative to the content of the polyolefin resin. By incorporating the urethane resin emulsion in the aqueous resin composition at the above-mentioned specific mass ratio relative to the content of the polyolefin resin, a coating layer with further improved dry laminate strength is likely to be obtained. The mass ratio can be calculated by {urethane resin content / polyolefin resin content} × 100, based on the total mass of the aqueous resin composition, or {urethane resin content / polyolefin resin content} × 100, based on the mass of the solids content of the aqueous resin composition.

[0041] The urethane resin emulsion can be obtained by reacting a diisocyanate such as isophorone diisocyanate, a polyol such as polycarbonate diol, a diol such as diethylene glycol, and a diol monocarboxylic acid such as dimethylolpropanoic acid, and then self-emulsifying the mixture in alkaline water while chain-extending with isophorone diamine.Urethane resin emulsions with dispersed particle diameters (number average particle diameters) of 10 to 200 nm can be used.

[0042] As the urethane resin emulsion, a commercially available product may be used. Examples of commercially available urethane resin emulsions include "WBR-2120C" and "WBR-2122C" manufactured by Taisei Fine Chemical Co., Ltd., and "Takelac W-5030" manufactured by Mitsui Chemicals, Inc. One type of urethane resin emulsion may be used alone, or two or more types may be used in combination.

[0043] 〔wax〕 The aqueous resin composition contains a wax. The wax is a component that constitutes the solid content of the aqueous resin composition. The wax includes at least one wax selected from the group consisting of polyethylene waxes and paraffin waxes.

[0044] The inclusion of a polyethylene wax and / or a paraffin wax in the aqueous resin composition contributes to the formation of a coating layer with good blocking resistance, heat seal blocking resistance, and scratch resistance. If the aqueous resin composition does not contain the polyethylene wax and the paraffin wax but instead contains another wax (e.g., carnauba wax), the coating layer will have poor heat seal blocking resistance and scratch resistance.

[0045] The wax content in the aqueous resin composition is 4 to 25% by mass, based on the mass of the solid content of the aqueous resin composition. By setting the wax content within this range relative to the mass of the solid content of the aqueous resin composition, it is possible to contribute to the formation of a coating layer that has good heat seal blocking resistance and scratch resistance and that is also transparent. If the wax content is less than 4% by mass relative to the mass of the solid content of the aqueous resin composition, the coating layer will have poor heat seal blocking resistance and scratch resistance. On the other hand, if the wax content exceeds 25% by mass relative to the mass of the solid content of the aqueous resin composition, the coating layer will have poor transparency. The wax content relative to the mass of the solid content of the aqueous resin composition is preferably 4 to 15% by mass from the viewpoint of easily obtaining a coating layer with better substrate adhesion, hot melt adhesive properties, and transparency, and is preferably 5 to 25% by mass from the viewpoint of easily obtaining a coating layer with better blocking resistance. The wax content is the total content of waxes including polyethylene wax and paraffin wax, and is preferably the total content of polyethylene wax and paraffin wax.

[0046] The mass ratio of the wax content to the polyolefin resin content is polyolefin resin:wax = 1:0.043 to 1:0.300. By setting the mass ratio of the wax content to the polyolefin resin content within this range, a coating layer with better substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, scratch resistance, and transparency can be obtained. If the ratio of the wax content to the polyolefin resin content is less than 0.043, the coating layer will have poor blocking resistance, heat seal blocking resistance, and scratch resistance. On the other hand, if the ratio of the wax content to the polyolefin resin content is more than 0.300, the substrate adhesion, heat seal blocking resistance, hot melt adhesive properties, scratch resistance, and transparency will be poor.

[0047] (Polyethylene wax) The aqueous resin composition preferably contains the above-mentioned aqueous dispersion of polyethylene wax, i.e., the polyethylene wax dispersed in particulate form in the aqueous resin composition. In this case, the average particle size of the polyethylene wax is preferably 0.3 to 8 μm. When the average particle size of the polyethylene wax is within the above range, a coating layer with even better transparency, blocking resistance, and scratch resistance is more likely to be obtained. From the viewpoint of improving the transparency of the coating layer, the average particle size of the polyethylene wax is more preferably 0.3 to 3.5 μm, and from the viewpoint of improving the blocking resistance and scratch resistance of the coating layer, the average particle size of the polyethylene wax is more preferably 0.7 to 8 μm.

[0048] In the present disclosure, the average particle size of wax is the particle size at a cumulative frequency of 50% on a volume basis (median size: D50), which is calculated from the particle size distribution measured on a volume basis by the Coulter Counter method, and is also referred to as the volume-average particle size. The Coulter Counter method is a method in which wax particles dispersed in a liquid 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.

[0049] The penetration of the polyethylene wax is preferably 0.3 to 13, more preferably 1 to 12, and from the viewpoint of scratch resistance, even more preferably 2 to 11. In the present disclosure, the penetration of the wax can be a value measured at a sample temperature of 25°C by a method in accordance with JIS K 2235:2009.

[0050] The polyethylene wax may be produced by a conventional method or may be a commercially available product, such as the "CHEMIPEARL" series (aqueous dispersion of polyethylene wax manufactured by Mitsui Chemicals, Inc.).

[0051] When a polyethylene wax is contained in the aqueous resin composition, the content of the polyethylene wax in the aqueous resin composition is preferably 0.2 to 15% by mass, more preferably 0.4 to 10% by mass, and even more preferably 0.5 to 8% by mass, based on the mass of the solids of the aqueous resin composition. By controlling the content of the polyethylene wax within the above range relative to the mass of the solids of the aqueous resin composition, a coating layer with better heat seal blocking resistance and scratch resistance is easily obtained. From this perspective, an aqueous resin composition containing a polyethylene wax in the above range can be suitably used for the aqueous coating liquid that forms the coating layer in the laminates having a reverse-printing configuration and a front-printing configuration, which will be described later. In particular, by containing a polyethylene wax in the aqueous resin composition, the blocking resistance of the laminates having a reverse-printing configuration, which will be described later, can be further improved.

[0052] (paraffin wax) The melting point of the paraffin wax is preferably 50 to 120°C. By using a paraffin wax having a melting point within the above range, a coating layer with even better heat seal blocking resistance is more likely to be obtained. From the viewpoint of improving heat seal blocking resistance, the melting point of the paraffin wax is more preferably 50 to 100°C. If the melting point of the paraffin wax is less than 50°C, the heat seal blocking resistance may be slightly reduced. On the other hand, if the melting point of the paraffin wax is more than 120°C, the heat seal blocking resistance may be slightly reduced, but the evaluation results showed that all of the objectives of the present invention can be achieved. The melting point of the paraffin wax can be measured by differential scanning calorimetry (DSC).

[0053] The paraffin wax may be produced by a conventional method or may be a commercially available product. As with polyethylene wax, a paraffin wax aqueous dispersion may also be used. Examples of commercially available paraffin waxes include the "AQUACER" series (manufactured by Big Chemie Japan).

[0054] When a paraffin wax is contained in the aqueous resin composition, the content of the paraffin wax in the aqueous resin composition is preferably 1 to 24% by mass, more preferably 3 to 22% by mass, based on the mass of the solids of the aqueous resin composition. By setting the content of the paraffin wax within the above range relative to the mass of the solids of the aqueous resin composition, a coating layer with better heat seal blocking resistance and scratch resistance is easily obtained. From this perspective, an aqueous resin composition containing a paraffin wax in the above range can be suitably used in the aqueous coating liquid that forms the coating layer of the surface-printed laminate described below. In particular, by including a paraffin wax in the aqueous resin composition, the heat seal blocking resistance and scratch resistance of the surface-printed laminate described below can be further improved.

[0055] On the other hand, from the viewpoint of making it easier to increase the dry laminate strength of the coating layer, the content of the paraffin wax relative to the mass of the solid content of the aqueous resin composition is preferably 0 to 10 mass%, more preferably 0 to 5 mass%. By setting the content of the paraffin wax relative to the mass of the solid content of the aqueous resin composition to 0 to 10 mass%, it is possible to achieve the above-mentioned dry laminate strength of 1.2 N / 15 mm or more. From this viewpoint, an aqueous resin composition in which the content of the paraffin wax relative to the solid content is limited to the above range can be suitably used for the aqueous coating liquid that forms the coating layer in a laminate having the configuration of a laminate film described below.

[0056] [Film-forming aid] The aqueous resin composition preferably further contains a coalescing aid. When the aqueous resin composition contains a coalescing aid, a coating layer with even better transparency is more easily obtained. The boiling point of the coalescing aid is preferably 70 to 260°C, more preferably 90 to 245°C, and from the viewpoint of improving substrate adhesion, blocking resistance, and transparency, even more preferably 130 to 240°C. The coalescing aid with a boiling point of 70 to 260°C is a component that constitutes the volatile matter in the aqueous resin composition.

[0057] When the aqueous resin composition contains a coalescing agent, the content of the coalescing agent in the aqueous resin composition relative to the content of the wax is preferably a mass ratio of 0.05 to 2.5, and more preferably 0.1 to 2.5 from the viewpoint of the transparency of the coating layer. When the mass ratio of the coalescing agent content to the wax content is within the above range, the film adhesion and heat seal blocking resistance of the coating layer are improved. The above mass ratio can be determined by the content of coalescing agent / the content of wax in the aqueous resin composition.

[0058] Examples of film-forming aids having a boiling point of 70 to 260°C include dimethyl glycol (DMG, also known as 1,2-dimethoxyethane; boiling point 85.2°C), dimethyl diglycol (DMDG, also known as diethylene glycol dimethyl ether; boiling point 162°C), dimethyl triglycol (DMTG, also known as triethylene glycol dimethyl ether; boiling point 216°C), methyl ethyl diglycol (MEDG, also known as diethylene glycol methyl ethyl ether; boiling point 176°C), diethyl diglycol (DEDG, also known as diethylene glycol diethyl ether; boiling point 188.9°C), and dibutyl diglycol. Examples of suitable coal-forming agents include coal (DBDG, also known as diethylene glycol dibutyl ether; boiling point 255°C), dimethylpropylene diglycol (DMFDG, also known as dipropylene glycol dimethyl ether; boiling point 175°C), propylene glycol (PG; boiling point 188.2°C), dipropylene glycol n-butyl ether (DPnB; boiling point 230°C), propylene glycol monomethyl ether (PM; boiling point 121°C), isopropyl alcohol (IPA; boiling point 82.4°C), ethanol (boiling point 78°C), and polyethylene glycol having a number average molecular weight of 200 (PEG200; boiling point 250°C). These may be used alone or in combination of two or more. When multiple coal-forming agents are used in combination, the preferred boiling points mentioned above refer to the boiling points of each agent, and the mass ratio of the coal-forming agent content to the wax content refers to the total content of the multiple coal-forming agents relative to the wax content.

[0059] Among the above specific examples, the coalescent preferably contains at least one selected from the group consisting of diethyl diglycol, propylene glycol, dipropylene glycol n-butyl ether, propylene glycol monomethyl ether, isopropyl alcohol, ethanol, and polyethylene glycol.Furthermore, the coalescent more preferably contains at least one selected from the group consisting of diethyl diglycol, propylene glycol, and dipropylene glycol n-butyl ether.

[0060] [Surfactant] The aqueous resin composition may further contain a surfactant, if necessary. The surfactant is a component that constitutes the solid content of the aqueous resin composition. By adding a surfactant to the aqueous resin composition, the surface tension of the aqueous resin composition or the aqueous coating liquid can be adjusted, and the transparency of the coating layer can be easily improved. Examples of surfactants include organic surfactants, silicone surfactants, acetylene glycol surfactants, fluorine surfactants, and alkylene oxide surfactants. One of these surfactants may be used alone, or two or more may be used in combination. Among these, organic surfactants are preferred from the viewpoint of easily obtaining a coating layer with better transparency. Commercially available surfactant products can be preferably used because of their ease of availability.

[0061] The organic surfactant is preferably at least one selected from the group consisting of anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, and semi-polar surfactants.

[0062] More specifically, examples of anionic surfactants include saturated or unsaturated fatty acid salts (e.g., sodium laurate, sodium stearate, sodium oleate, sodium linolenate, etc.), alkyl sulfates, alkylbenzenesulfonic acids (e.g., hexylbenzenesulfonic acid, octylbenzenesulfonic acid, dodecylbenzenesulfonic acid, etc.) and salts thereof, polyoxyalkylene alkyl ether sulfates, polyoxyalkylene alkenyl ether sulfates, polyoxyethylene alkyl sulfate ester salts, sulfosuccinic acid alkyl ester salts, polyoxyalkylene sulfosuccinic acid alkyl ester salts, polyoxyalkylene alkylphenyl ether sulfates, alkanesulfonates, octyltrimethylammonium hydroxide, dodecyltrimethylammonium hydroxide, Examples of the salt include oxides, alkyl sulfonates, polyoxyethylene alkylphenyl ether sulfates, polyoxyalkylene alkyl ether acetates, alkyl phosphates, polyoxyalkylene alkyl ether phosphates, acyl glutamates, α-acyl sulfonates, alkyl sulfonates, alkyl aryl sulfonates, α-olefin sulfonates, alkyl naphthalene sulfonates, alkanesulfonates, alkyl or alkenyl sulfates, alkyl amide sulfates, alkyl or alkenyl phosphates, alkyl amide phosphates, alkylyl alkyl taurine salts, N-acyl amino acid salts, sulfosuccinates, alkyl ether carboxylates, amide ether carboxylates, α-sulfofatty acid ester salts, alanine derivatives, glycine derivatives, and arginine derivatives. Examples of the salt include alkali metal salts such as sodium salts, alkaline earth metal salts such as magnesium salts, alkanolamine salts such as triethanolamine salts, and even ammonium salts.

[0063] Examples of cationic surfactants include quaternary ammonium salts such as alkyltrimethylammonium chloride and benzalkonium chloride, and amine salts such as stearic acid diethylaminoethylamide.

[0064] Nonionic surfactants include polyoxyalkylene ethers, polyoxyalkylene alkyl ethers, polyoxyalkylene fatty acid esters, polyoxyalkylene fatty acid diesters, polyoxyalkylene resin acid esters, polyoxyalkylene (hydrogenated) castor oils, polyoxyalkylene alkylphenols, polyoxyalkylene alkylphenyl ethers, polyoxyalkylene phenylphenyl ethers, polyoxyalkylene alkyl esters, polyoxyalkylene alkyl esters, sorbitan fatty acid esters, and polyoxyalkylene sorbitan alkyl esters. Examples of the surfactants include polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene glycerin fatty acid esters, polyglycerin alkyl ethers, polyglycerin fatty acid esters, sucrose fatty acid esters, fatty acid alkanolamides, alkyl glucosides, polyoxyalkylene fatty acid bisphenyl ethers, polypropylene glycol, diethylene glycol, fluorine-based surfactants, polyoxyethylene-polyoxypropylene block polymers, and alkyl polyoxyethylene-polyoxypropylene block polymer ethers.

[0065] Examples of amphoteric surfactants include imidazoline-type, amidobetaine-type, alkylbetaine-type, alkylamidobetaine-type, alkylsulfobetaine-type, amidosulfobetaine-type, hydroxysulfobetaine-type, carbobetaine-type, phosphobetaine-type, aminocarboxylic acid-type, and amidoamino acid-type amphoteric surfactants. Specific examples include imidazoline-type amphoteric surfactants such as 2-undecyl-N,N,N-(hydroxyethylcarboxymethyl)-2-imidazoline sodium and 2-cocoyl-2-imidazolinium hydroxide-1-carboxyethyloxy disodium salt; alkylbetaine-type amphoteric surfactants such as lauryl dimethylaminoacetic acid betaine and myristyl betaine; coconut oil fatty acid amidopropyl dimethylaminoacetic acid betaine, palm kernel oil fatty acid amidopropyl dimethylaminoacetic acid betaine, beef tallow fatty acid amidopropyl dimethylaminoacetic acid betaine, hardened beef tallow fatty acid amidopropyl dimethylaminoacetic acid betaine, lauryl dimethylaminoacetic acid betaine, and the like. amidobetaine-type amphoteric surfactants such as carboxylic acid amidopropyl dimethylaminoacetic acid betaine, myristate amidopropyl dimethylaminoacetic acid betaine, palmitate amidopropyl dimethylaminoacetic acid betaine, stearate amidopropyl dimethylaminoacetic acid betaine, and oleate amidopropyl dimethylaminoacetic acid betaine; alkyl sulfobetaine-type amphoteric surfactants such as coconut oil fatty acid dimethyl sulfopropyl betaine; alkyl hydroxysulfobetaine-type amphoteric surfactants such as lauryl dimethylaminohydroxysulfobetaine; phosphobetaine-type amphoteric surfactants such as lauryl hydroxyphosphobetaine;N-Lauroyl-N'-hydroxyethyl-N'-carboxymethylethylenediamine sodium, N-oleoyl-N'-hydroxyethyl-N'-carboxymethylethylenediamine sodium, N-Cocoyl-N'-hydroxyethyl-N'-carboxymethylethylenediamine sodium, N-Lauroyl-N'-hydroxyethyl-N'-carboxymethylethylenediamine potassium, N-Oleoyl-N'-hydroxyethyl-N'-carboxymethylethylenediamine potassium, N-Lauroyl-N'-hydroxyethyl-N'-carboxymethylethylenediamine sodium, N-Oleoyl-N'-hydroxyethyl-N'-carboxymethylethylenediamine sodium, N-Cocoyl-N-hydroxyethyl-N'-carboxymethylethylenediamine sodium Examples include amide amino acid type amphoteric surfactants such as sodium dimethylethylenediamine, N-lauroyl-N-hydroxyethyl-N',N'-dicarboxymethylethylenediamine monosodium, N-oleoyl-N-hydroxyethyl-N',N'-dicarboxymethylethylenediamine monosodium, N-cocoyl-N-hydroxyethyl-N',N'-dicarboxymethylethylenediamine monosodium, N-lauroyl-N-hydroxyethyl-N',N'-dicarboxymethylethylenediamine disodium, N-oleoyl-N-hydroxyethyl-N',N'-dicarboxymethylethylenediamine disodium, and N-cocoyl-N-hydroxyethyl-N',N'-dicarboxymethylethylenediamine disodium;

[0066] Examples of semi-polar surfactants include alkylamine oxide surfactants, alkylamine oxides, alkylamidoamine oxides, and alkylhydroxyamine oxides, and alkyldimethylamine oxides having 10 to 18 carbon atoms and alkoxyethyldihydroxyethylamine oxides having 8 to 18 carbon atoms are preferably used.Specifically, dodecyl dimethylamine oxide, dimethyloctylamine oxide, diethyldecylamine oxide, bis-(2-hydroxyethyl)dodecylamine oxide, dipropyltetradecylamine oxide, methylethylhexadecylamine oxide, dodecylamidopropyldimethylamine oxide, cetyldimethylamine oxide, stearyldimethylamine oxide, tallow dimethylamine oxide, dimethyl-2-hydroxyoctadecylamine oxide, lauryldimethylamine oxide, myristyldimethylamine oxide, stearyldimethylamine oxide, isostearyldimethylamine oxide, coconut fatty acid alkyl dimethylamine oxide, caprylic acid amidopropyl dimethylamine oxide, capric acid amidopropyl dimethylamine oxide, lauric acid amidopropyl dimethylamine oxide, myristic acid amidopropyl dimethylamine oxide, palmitic acid amidopropyl dimethylamine oxide, stearyl Examples include phosphoric acid amidopropyl dimethylamine oxide, isostearic acid amidopropyl dimethylamine oxide, oleic acid amidopropyl dimethylamine oxide, ricinoleic acid amidopropyl dimethylamine oxide, 12-hydroxystearic acid amidopropyl dimethylamine oxide, coconut fatty acid amidopropyl dimethylamine oxide, palm kernel oil fatty acid amidopropyl dimethylamine oxide, castor oil fatty acid amidopropyl dimethylamine oxide, lauric acid amidoethyl dimethylamine oxide, myristic acid amidoethyl dimethylamine oxide, coconut fatty acid amidoethyl dimethylamine oxide, lauric acid amidoethyl diethylamine oxide, myristic acid amidoethyl diethylamine oxide, coconut fatty acid amidoethyl diethylamine oxide, lauric acid amidoethyl dihydroxyethylamine oxide, myristic acid amidoethyl dihydroxyethylamine oxide, and coconut fatty acid amidoethyl dihydroxyethylamine oxide.

[0067] When the aqueous resin composition further contains a surfactant, the content of the solid content of the surfactant is preferably 0.01 to 6 mass % relative to the mass of the solid content of the aqueous resin composition, from the viewpoint of easily obtaining a coating layer with better transparency.

[0068] [Curing Agents and Crosslinking Agents] The aqueous resin composition may further contain at least one selected from the group consisting of a curing agent and a crosslinking agent (hereinafter, sometimes referred to as "curing agent and / or crosslinking agent"). Alternatively, the aqueous resin composition may be used together with a curing agent and / or a crosslinking agent without containing a curing agent or a crosslinking agent. For example, as a two-component type, an aqueous coating liquid may be prepared by mixing the aqueous resin composition and a curing agent and / or a crosslinking agent, and the resulting aqueous coating liquid may be applied to a substrate such as a plastic film. The use of a curing agent and / or a crosslinking agent makes it easier to obtain an aqueous coating liquid capable of forming a coating film with excellent coating film properties such as substrate adhesion, water resistance, and abrasion resistance.

[0069] (hardening agent) Examples of curing agents 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. Among these, isocyanate-based curing agents, carbodiimide-based curing agents, and aziridine-based curing agents are preferred from the viewpoint of two-component stability. These curing agents may be used alone or in combination of two or more. Among these, isocyanate-based curing agents are preferred from the viewpoint of excellent pot life, and aziridine-based curing agents are preferred from the viewpoint of easily obtaining a coating film that is excellent in wet friction resistance and dry friction resistance.

[0070] The isocyanate-based curing agent may be a polyvalent isocyanate compound, which may be produced by a known method or may be a commercially available product. Specific commercially available isocyanate curing agents include those manufactured by Mitsui Chemicals, Inc. under the trade 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 Industries Co., Ltd. under the trade names "Aquanate 100," "Aquanate 110," "Aquanate 200," and "Aquanate 210"; those manufactured by Asahi Kasei Corporation under the trade 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 trade name "Bayhydur 3100," "Bayhydur 302," "Bayhydur 304," "Bayhydur 305," "Bayhydur XP2451 / 1," "Bayhydur XP2487 / 1," "Bayhydur XP2547," "Bayhydur XP2655," and "Bayhydur XP2700"; BASF products under the trade names "Basonat HW100," "Basonat HA100," and "Basonat HW1180PC," and Dainichiseika Color & Chemicals Mfg. Co., Ltd. under the trade name "Hydric FC Hardener." Examples of isocyanate curing agents include a single type used alone, or two or more types may be used in combination.

[0071] Specific examples of blocked isocyanate curing agents include isocyanate curing agents blocked with a blocking agent (e.g., alcohol compounds, phenol compounds, oxime compounds, lactam compounds, pyrazole compounds, active methylene compounds, etc.) These blocked isocyanate curing agents may be used alone or in combination of two or more.

[0072] A carbodiimide curing agent is a compound containing two or more carbodiimide groups in one molecule. Specific examples of carbodiimide curing agents include poly(4,4'-diphenylmethanecarbodiimide), poly(dicyclohexylmethanecarbodiimide), and poly(diisopropylcarbodiimide). Commercially available carbodiimide curing agents include the "Carbodilite" series manufactured by Nisshinbo Chemical Inc. and the "AB Hardener" series manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. These carbodiimide curing agents may be used alone or in combination of two or more.

[0073] An oxazoline-based curing agent is a compound containing two or more oxazoline groups per molecule. Specific examples of oxazoline-based curing agents include polyhydric oxazolines such as 2,2'-bis-(2-oxazoline), 2,2'-methylene-bis-(2-oxazoline), and 2,2'-(1,4-phenylene)-bis(2-oxazoline), as well as polymers or copolymers having oxazoline-group-containing monomer units such as 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, and 2-isopropenyl-5-ethyl-2-oxazoline. Each oxazoline-group-containing monomer may be used alone, or two or more types may be used. Furthermore, a copolymer of an oxazoline-group-containing monomer and another monomer copolymerizable with this monomer may also be used. 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.

[0074] Epoxy curing agents are compounds containing two or more epoxy groups per molecule. Specific examples of epoxy curing agents include bisphenol A epoxy compounds, bisphenol F 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 curing agents include the "jER" series manufactured by Mitsubishi Chemical Corporation and the "Denacol EX" series manufactured by Nagase ChemteX Corporation. These epoxy curing agents may be used alone or in combination.

[0075] An aziridine curing agent is a compound containing two or more aziridine groups per molecule. Specific examples of aziridine curing agents include 2,2-bishydroxymethylbutanol-tris[3-(1-aziridinyl)propionate] and 4,4'-bis(ethyleneiminocarbonylamino)diphenylmethane. Commercially available aziridine curing agents include the "ChemiTite" series manufactured by Nippon Shokubai and the "Hydric RA Hardener" manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd. These aziridine curing agents may be used alone or in combination of two or more.

[0076] When an aqueous resin composition and a curing agent are used in combination, the aqueous resin composition and the curing agent are preferably mixed so that the solid content of the curing agent is 0.1 to 10 parts by mass per 100 parts by mass of the total mass of the aqueous resin composition. The amount of curing agent used is more preferably 0.3 to 7 parts by mass, and even more preferably 0.5 to 7 parts by mass. By using an amount of curing agent within the above range, an aqueous coating liquid that is excellent in fluidity during coating and in pot life after mixing with the curing agent is easily obtained.

[0077] (Crosslinking agent) Examples of the crosslinking agent include an isocyanate-based crosslinking agent, a blocked isocyanate-based crosslinking agent, a carbodiimide-based crosslinking agent, an oxazoline-based crosslinking agent, an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, a silane coupling agent, and a titanium coupling agent. Among these, an isocyanate-based crosslinking agent is preferred from the viewpoint of easily obtaining a coating layer with good abrasion resistance.

[0078] Specific examples of isocyanate-based crosslinking agents include polyvalent isocyanate compounds. Specific examples of blocked isocyanate-based crosslinking agents include blocked isocyanate-based crosslinking agents with blocking agents (e.g., alcohol-based compounds, phenol-based compounds, oxime-based compounds, lactam-based compounds, pyrazole-based compounds, and active methylene compounds). Specific examples of carbodiimide-based crosslinking agents include the "Carbodilite" series manufactured by Nisshinbo Chemical Inc. Specific examples of oxazoline-based crosslinking agents include the "Epocross" series manufactured by Nippon Shokubai Co., Ltd. Specific examples of epoxy-based crosslinking agents include the "jER" series manufactured by Mitsubishi Chemical Corporation. Specific examples of aziridine-based crosslinking agents include the "ChemiTite" series manufactured by Nippon Shokubai Co., Ltd. Specific examples of silane coupling agents include 3-glycidoxypropyltrimethoxysilane. A specific example of the titanium coupling agent is titanium di-2-ethylhexoxybis(2-ethyl-3-hydroxyhexoxide), etc. These cross-linking agents may be used alone or in combination of two or more.

[0079] When the aqueous resin composition and the crosslinking agent are used in combination, the aqueous resin composition and the crosslinking agent are preferably mixed so that the solid content of the crosslinking agent is 0.1 to 10 parts by mass relative to 100 parts by mass of the total mass of the aqueous resin composition. The amount of the crosslinking agent used is more preferably 0.3 to 7 parts by mass, and even more preferably 0.5 to 7 parts by mass.

[0080] [Aqueous medium] The aqueous resin composition contains the polyolefin resin emulsion described above, and therefore contains an aqueous medium containing at least water. The aqueous medium may be the aqueous medium contained in the polyolefin resin emulsion described above, and in resin emulsions such as acrylic resin emulsions and urethane resin emulsions that are used as needed. Furthermore, when an aqueous dispersion of wax is used as the wax described above, the aqueous resin composition may contain the aqueous medium in the aqueous dispersion of wax in addition to the aqueous medium in the resin emulsion. Furthermore, the aqueous resin composition may contain an aqueous medium such as water used to adjust the viscosity and solid content, separate from the aqueous medium in the resin emulsion or the aqueous dispersion of wax.

[0081] As the aqueous medium, water or a mixed solvent of water and an organic solvent can be used. The organic 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 60 to 100% by mass, more preferably 70 to 100% by mass, and even more preferably 80 to 100% by mass.

[0082] [Other ingredients] (colorant) The aqueous resin composition may contain at least one colorant selected from the group consisting of pigments and dyes. By adding a colorant to the aqueous resin composition, a resin composition for an aqueous ink can be obtained, and the aqueous ink can be prepared using the resin composition for an aqueous ink.

[0083] Both organic and inorganic pigments can be used as pigments. Examples of organic pigments include azo pigments such as monoazo and condensed azo; threne pigments such as anthraquinone, perinone, perylene, and thioindigo; phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; quinacridone pigments; dioxazine pigments; isoindolinone pigments; pyrrolopyrrole pigments; aniline black; and organic fluorescent pigments. Examples of inorganic pigments include natural products such as clay, baryte, mica, and talc; ferrocyanides such as Prussian blue; sulfides such as zinc sulfide; sulfates such as barium sulfate; oxides such as chromium oxide, zinc white, titanium oxide, and iron oxide; hydroxides such as aluminum hydroxide; silicates such as calcium silicate and ultramarine; carbonates such as calcium carbonate and magnesium carbonate; carbon such as carbon black and graphite; metal powders such as aluminum powder, bronze powder, and zinc powder; and calcined pigments. These pigments may be used alone or in combination of two or more.

[0084] When the aqueous resin composition is used as a resin composition for aqueous ink containing a coloring material such as a pigment, the content of the coloring material relative to the total mass of the aqueous resin composition (resin composition for aqueous ink) is preferably 1 to 60 mass%. When an organic pigment is used as the coloring material, the content of the organic pigment relative to the total mass of the aqueous resin composition (resin composition for aqueous ink) is preferably 1 to 35 mass%. When an inorganic pigment such as titanium oxide or barium sulfate is used as the coloring material, the content of the inorganic pigment is preferably 10 to 60 mass% relative to the total mass of the aqueous resin composition (resin composition for aqueous ink).

[0085] (Other additives) The aqueous resin composition may further contain other additives as necessary. Examples of other additives include plasticizers, antiblocking agents, dispersants, antisettling agents, leveling agents, antifoaming agents, matting agents, pH adjusters, antioxidants, ultraviolet absorbers, light stabilizers, preservatives, antifungal agents, rust inhibitors, flame retardants, color developers, chelating agents, and coupling agents. These additives may be used alone or in combination of two or more.

[0086] The content of the additive is not particularly limited, but is, for example, preferably 0 to 20 mass %, more preferably 0 to 15 mass %, and even more preferably 0 to 10 mass %, relative to the total mass of the aqueous resin composition.

[0087] [Total solids] The total solids content (total mass of solids) of the aqueous resin composition is preferably 3 to 60 mass%, more preferably 5 to 50 mass%, and even more preferably 5 to 40 mass%, based on the total mass of the aqueous resin composition, and from the viewpoint of improving storage stability in particular. By setting the total solids content of the aqueous resin composition within the above range, storage stability and ink fluidity can be improved. If the total solids content of the aqueous resin composition is less than 3 mass%, based on the total mass of the aqueous resin composition, the drying properties of the coating film upon application tend to be insufficient. On the other hand, if the total solids content of the aqueous resin composition is more than 60 mass%, based on the total mass of the aqueous resin composition, the fluidity of the aqueous coating liquid tends to be insufficient, but the evaluation results showed that all of the objectives of the present invention can be achieved.

[0088] [Component Contents in Aqueous Resin Composition] From the viewpoint of easily obtaining the desired coating layer, the content of the polyolefin resin having a melting point of 60 to 97°C and an acid value of 13 to 60 mgKOH / g in the aqueous resin composition is preferably 2 to 57 mass%, more preferably 3 to 46 mass%, based on the total mass of the aqueous resin composition, and from the viewpoint of substrate adhesion, even more preferably 3 to 38 mass%. Furthermore, the content of wax (total of polyethylene-based wax and paraffin-based wax) in the aqueous resin composition is preferably 0.2 to 15 mass%, more preferably 0.4 to 12 mass%, based on the total mass of the aqueous resin composition, and from the viewpoint of heat seal blocking resistance, even more preferably 0.5 to 10 mass%. The content of the film-forming aid in the aqueous resin composition is preferably 0.2 to 15 mass%, more preferably 0.4 to 12 mass%, based on the total mass of the aqueous resin composition, and from the viewpoint of transparency, even more preferably 0.5 to 10 mass%.

[0089] (Method of producing aqueous resin composition) The aqueous resin composition can be prepared by mixing the polyolefin resin emulsion and wax, as well as other components used as needed, in a conventional manner so that the desired content of each component is achieved. The polyolefin resin emulsion and wax may each be liquid, or the wax may be solid. That is, the aqueous resin composition may be prepared by pre-mixing a liquid component with a solid component to form a liquid, or by mixing all liquid components to form a liquid. Components used as needed other than the polyolefin resin emulsion and wax include the acrylic resin emulsion, urethane resin emulsion, film-forming agent, surfactant, curing agent, crosslinking agent, aqueous medium, colorant, and other additives.

[0090] It is also possible to provide a solid resin composition obtained by drying the aqueous resin composition. This solid resin composition contains the polyolefin resin and the wax, and the polyolefin resin content in the solid resin composition is 60 to 95 mass % and the wax content is 4 to 25 mass %. The mass ratio of the wax content to the polyolefin resin content is polyolefin resin:wax = 1:0.043 to 1:0.300.

[0091] By using the aqueous resin composition described above, it is possible to easily prepare an aqueous coating liquid capable of forming a coating layer that has excellent substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, as well as transparency. Examples of such aqueous coating liquids include the aqueous varnish, aqueous medium, aqueous primer, and aqueous reducer described below, as well as aqueous ink containing a colorant. The aqueous medium is used as a hue-adjusting liquid by mixing with the aqueous ink. The aqueous varnish is used to form a varnish layer such as an overcoat layer, and the aqueous primer is used to form a primer layer that is applied to the substrate before printing with ink or the like.

[0092] <Water-based coating liquid> An aqueous coating fluid according to one embodiment of the present invention (sometimes simply referred to as "aqueous coating fluid" in the present disclosure) contains the aqueous resin composition described above. Accordingly, the aqueous coating fluid contains at least a resin emulsion containing the polyolefin resin emulsion described above, and a polyethylene wax and / or a paraffin wax. Furthermore, the aqueous coating fluid forms a coating film having a haze value of 15% or less.

[0093] Depending on the type, application, and coating method of the aqueous coating liquid, various aqueous coating liquids can be prepared by adding a liquid medium (e.g., an aqueous medium) to the aqueous resin composition as needed to adjust the viscosity, or by adding appropriate additives (e.g., the other additives mentioned above). Alternatively, depending on the type, application, and coating method of the aqueous coating liquid, various aqueous coating liquids can be prepared by mixing the polyolefin resin emulsion and wax, as well as other components used as needed, in a conventional manner to achieve the desired component contents. Components used as needed in addition to the polyolefin resin emulsion and wax include the acrylic resin emulsion, urethane resin emulsion, film-forming aid, surfactant, curing agent, crosslinking agent, aqueous medium, colorant, and other additives mentioned above. Suitable aqueous coating liquids include those for flexographic or gravure printing, and include aqueous varnishes, aqueous media, aqueous primers, aqueous reducers, and aqueous inks containing colorants.

[0094] The aqueous varnish, aqueous medium, aqueous primer, and aqueous reducer can be prepared without substantially containing a colorant in the aqueous resin composition. Therefore, when the aqueous coating liquid is an aqueous varnish, aqueous medium, aqueous primer, or aqueous reducer, the content of each component relative to the mass of the solids of the aqueous coating liquid can be the same as the content of each component relative to the mass of the solids of the aqueous resin composition. For example, the content of the polyolefin resin can be 60 to 95 mass% and the content of the wax can be 4 to 25 mass% relative to the mass of the solids of the aqueous coating liquid that is an aqueous varnish, aqueous medium, aqueous primer, or aqueous reducer.

[0095] On the other hand, aqueous inks can be easily prepared using a resin composition for aqueous inks obtained by adding a coloring material such as a pigment to an aqueous resin composition. Therefore, when the aqueous coating liquid is an aqueous ink, the content of each component relative to the mass of the solids of the aqueous ink excluding the coloring material can be the same as the content of each component relative to the mass of the solids of the aqueous resin composition described above. For example, the content of the polyolefin resin can be 60 to 95 mass% and the content of the wax can be 4 to 25 mass% relative to the mass of the solids of the aqueous ink (excluding the coloring material).

[0096] In addition, the wax content relative to the polyolefin resin content in the aqueous coating liquid, which is the above-mentioned aqueous varnish, aqueous medium, aqueous primer, aqueous reducer, or aqueous ink, can be set to a mass ratio of polyolefin resin:wax = 1:0.043 to 1:0.300.

[0097] The aqueous coating solution of this embodiment can form a coating layer that exhibits excellent substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, as well as transparency. By adopting the preferred configuration described above for the aqueous resin composition, the aqueous coating solution can also easily produce a coating layer with the above properties. Furthermore, an aqueous coating solution having a paraffin wax content of 0 to 10% by mass (preferably 0 to 5% by mass) relative to the solids content of the aqueous coating solution (excluding colorants when the aqueous coating solution is an aqueous ink) can form a coating layer with high dry laminate strength in addition to the above properties. Furthermore, an aqueous coating solution containing a urethane resin emulsion in which the urethane resin content is 55% by mass or less relative to the polyolefin resin content can also form a coating film with high dry laminate strength in addition to the above properties.

[0098] As described above, the aqueous coating liquid of this embodiment is suitable for flexographic printing or gravure printing and can be used as an aqueous ink, aqueous varnish, aqueous medium, aqueous primer, or aqueous reducer. That is, the aqueous coating liquid is suitable for flexographic printing or gravure printing, and can be used not only as an aqueous ink containing a colorant such as a pigment, but also as an aqueous varnish, aqueous medium, aqueous primer, or aqueous reducer that is substantially free of colorant. Coated products such as printed matter can be produced by combining the aqueous ink of this embodiment, which contains a colorant, with at least one of the aqueous varnish, aqueous medium, aqueous primer, and aqueous reducer of this embodiment that does not contain a colorant. From the standpoint of compatibility, it is particularly preferable to combine the aqueous ink of this embodiment, which has the same composition of components other than the colorant, with at least one of the aqueous varnish, aqueous medium, aqueous primer, and aqueous reducer of this embodiment.

[0099] <Laminate> A laminate according to one embodiment of the present invention (sometimes simply referred to as a "laminate" in the present disclosure) includes a substrate and a coating layer disposed on the substrate, the coating layer comprising a coating layer formed from the aqueous coating liquid described above. The coating layer in the laminate preferably comprises a coating layer formed from the aqueous coating liquid for flexographic printing or gravure printing described above, i.e., a coating layer formed by flexographic printing or gravure printing of the aqueous coating liquid described above. Disposing a coating layer on a substrate includes a configuration in which a coating layer is formed by applying the aqueous coating liquid described above to the surface of a substrate, as well as a configuration in which a coating layer formed from the aqueous coating liquid described above is provided on the surface of a substrate via another layer. Using the aqueous coating liquid described above for the coating layer makes it possible to obtain a laminate having a coating layer that is transparent and exhibits good substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance.

[0100] For example, by printing an aqueous ink as an aqueous coating liquid on the surface of a substrate by a common printing method such as gravure printing or flexographic printing, a printed layer bearing a desired design, information, etc. can be formed as a coating layer. This makes it possible to obtain a printed matter as a laminate comprising the substrate and the printed layer having the above-mentioned properties provided on the substrate.

[0101] The laminate will be described in more detail below with reference to the drawings. Figures 1 and 2 are cross-sectional views each showing a schematic example of the arrangement of layers constituting a laminate according to one embodiment of the present invention. Therefore, the laminate shown in Figures 1 and 2 may have layers not shown between the layers shown in the figures. Note that the dimensional ratios in Figures 1 and 2 are different from the actual ones for the sake of convenience. When the laminate in Figures 1 and 2 is used as a label or packaging material, the surface that is visible is referred to as the front surface, and the opposite surface is referred to as the back surface.

[0102] 1 includes a substrate 11 and a coating layer 12 formed from the aqueous coating fluid of one embodiment of the present invention (hereinafter, may be referred to as "the present aqueous coating fluid") described above, which is disposed on the substrate 11. A laminate 20 shown in FIG. 2 includes a first substrate 21, a coating layer 22 formed from the aqueous coating fluid of one embodiment of the present invention (the present aqueous coating fluid), which is disposed on the first substrate 21, and a second substrate 23 disposed on the coating layer 22.

[0103] The coating layer 12 in the laminate 10 and the coating layer 22 in the laminate 20 may have a single layer structure or a multi-layer structure in which the aqueous coating liquid is applied in multiple layers. The thickness of the coating layers 12 and 22 (the total thickness in the case of a multi-layer structure in which the coating liquid is applied in multiple layers) is, for example, preferably 0.2 to 15 μm, more preferably 0.3 to 10 μm, even more preferably 0.5 to 5 μm, and particularly preferably 1 to 2 μm.

[0104] The laminates 10 and 20 may further include layers other than the substrates 11, 21, and 23 and the coating layers 12 and 22. Examples of such layers include other coating layers, such as pattern layers formed using printing ink, and vapor-deposited layers formed by vapor-depositing metals or metal oxides, such as aluminum or silica. For example, in the laminates 10 and 20, other coating layers or vapor-deposited layers may be provided on the surface of the substrates 11 and 21 on the side on which the coating layers 12 and 22 are provided, or on the surface opposite to that surface. Furthermore, in the laminate 20, an adhesive layer (not shown) formed by applying an adhesive to the surface of the coating layer 22 or the surface of the second substrate 23 may be provided between the coating layer 22 and the second substrate 23.

[0105] The laminate 10 may be configured such that the substrate 11 is the outermost layer and the coating layer 12 formed from the aqueous coating liquid is visible from the substrate 11 side (reverse printing configuration), or may be configured such that the coating layer 12 formed from the aqueous coating liquid is the outermost layer of the laminate 10 (front printing configuration). Either configuration can be suitably used.

[0106] (Reverse printing configuration) Specific examples of the reverse printing configuration include a laminate 10 comprising a substrate 11 and a first coating layer provided on the back surface of the substrate 11; a laminate 10 further comprising a second coating layer provided on the back surface of the first coating layer; a laminate 10 further comprising a primer layer formed between the substrate 11 and the first coating layer by applying a primer to the back surface of the substrate 11 before providing the first coating layer; and a laminate 10 further comprising a varnish layer, which serves as the outermost layer, formed on the back surface of the second coating layer by applying a varnish. In these specific examples of the reverse printing configuration, at least one of the first coating layer, second coating layer, primer layer, and varnish layer can be a coating layer 12 formed from the aqueous coating liquid. In order to make the properties of the coating layer 12 formed from this aqueous coating liquid more meaningful, in each of the above specific examples of the reverse printing configuration, it is preferable that the layer (first coating layer or primer layer) provided on the reverse side of the substrate 11 and the varnish layer that forms the outermost layer be a coating layer 12 formed from this aqueous coating liquid.

[0107] In a preferred example of the laminate 10 having the reverse printing configuration, the first coating layer can be a color print layer printed using color ink containing a coloring material such as a pigment to impart design and functionality. In this case, the substrate 11 in the laminate 10 is preferably a plastic film or the like that is transparent enough to allow the first coating layer, which is the color print layer, to be visible. Furthermore, in a preferred example of the laminate 10 having the reverse printing configuration, the second coating layer is preferably a white print layer formed by printing a white ink on the back surface of the first coating layer for purposes such as protecting the first coating layer, which is the color print layer, imparting hiding properties, and further improving the sharpness of the image of the color print layer. At least one of the color ink, white ink, primer, and varnish used in the laminate 10 having the reverse printing configuration may be the aqueous coating liquid, and known coating materials may also be used for the others. For example, the white ink may be a known white ink, or may be an aqueous coating liquid (aqueous ink) containing a coloring material such as a white pigment (for example, titanium oxide).

[0108] (Surface printing composition) Suitable examples of the surface printing configuration include a laminate 10 comprising a substrate 11 and a second coating layer provided on the surface of the substrate 11; a laminate 10 further comprising a first coating layer provided on the surface of the second coating layer; a laminate 10 further comprising a primer layer formed between the substrate 11 and the second coating layer by applying a primer to the surface of the substrate 11 before providing the second coating layer; and a laminate 10 further comprising a varnish layer, which serves as the outermost layer, formed by applying a varnish to the surface of the first coating layer. In these specific examples of the surface printing configuration, at least one of the first coating layer, second coating layer, primer layer, and varnish layer can be a coating layer 12 formed from the aqueous coating liquid. From the viewpoint of making the properties of the coating layer 12 formed from this aqueous coating liquid more meaningful, it is preferable that in each of the specific examples of the surface printing configuration described above, the primer layer, the first coating layer, and the varnish layer are coating layers 12 formed from this aqueous coating liquid.

[0109] In the specific example of the surface-printed laminate 10, the first coating layer can be a color print layer printed using a color ink containing a coloring material such as a pigment, for example, to impart design and functionality. Furthermore, in the specific example of the surface-printed laminate 10, the second coating layer provided on the surface of the substrate 11 is preferably a white print layer formed by printing a white ink on the surface of the substrate 11, for example, to impart hiding power to the first coating layer, which is a color print layer, or to further improve the sharpness of the image of the color print layer. The present aqueous coating liquid may be used for at least one of the color ink, white ink, primer, and varnish used in the surface-printed laminate 10, and known materials may also be used for the others. For example, the white ink may be a known white ink, or the present aqueous coating liquid (water-based ink) containing a coloring material such as a white pigment (e.g., titanium oxide) may also be used.

[0110] In each of the specific examples of the reverse printing configuration and the front printing configuration described above, the first coating layer may be provided on the entire surface of the layer on which it is to be provided (for example, the substrate 11 or primer layer in the reverse printing configuration, the second coating layer in the front printing configuration, etc.), or may be provided on only a portion of the surface. When the first coating layer is provided on only a portion of the surface of the layer on which it is to be provided, it is preferable that another coating layer, such as the above-mentioned varnish layer, be provided in the area of ​​the layer on which the first coating layer is not provided.

[0111] Each coating layer is obtained by applying a coating liquid (such as the above-mentioned aqueous coating liquid, as well as known inks, primers, and varnishes) and drying it. Furthermore, the same coating liquid may be applied (overcoated). The method for applying the coating liquid is not particularly limited, and known coating methods such as gravure printing, flexographic printing, brush coating, gravure coating, knife coating, reverse coating, die coating, bar coating, spray coating, flow coating, dip coating, spin coating, and curtain coating can be used. Multiple coating methods may be used for one laminate, depending on the type of coating liquid. Among the above-mentioned coating methods, gravure printing and flexographic printing are preferred due to their high quality and productivity.

[0112] 2 is a laminate 20 including a first substrate 21, a second substrate 23, and a coating layer 22 formed from the present aqueous coating liquid disposed therebetween, and is a laminate 20 having a so-called laminate film configuration. As described above, the laminate 20 may include layers other than the first substrate 21, the second substrate 23, and the coating layer 22. Examples of other layers include a pattern layer made of printing ink, an adhesive layer made of an adhesive, and a vapor-deposited layer formed by vapor-depositing a metal such as aluminum or silica or a metal oxide.

[0113] The laminate 20 preferably comprises a first substrate 21, a coating layer 22 formed from the present aqueous coating liquid and placed on the first substrate 21, an adhesive layer (not shown) formed from an adhesive and placed on the coating layer 22, and a second substrate 23 provided on the adhesive layer.

[0114] When the laminate 20 is to be a laminate film having the above-described configuration, it can be easily produced, for example, by the following method. First, the aqueous coating liquid is applied to a first substrate 21 using the above-described coating method to form a coating layer 22. Next, an adhesive is applied to the coating layer 22 using the above-described coating method to form an adhesive layer, and a second substrate 23 is bonded to the adhesive layer to produce a laminate film. Other layers may be provided between the first substrate 21 and the coating layer 22, between the coating layer 22 and the adhesive layer, and between the adhesive layer and the second substrate 23.

[0115] The method for laminating the second substrate 23 is not particularly limited, and suitable examples include extrusion lamination, dry lamination, and non-solvent lamination. In the extrusion lamination method, an anchor coating agent is applied to the coating layer 22 instead of the adhesive (adhesive layer), and then molten polyethylene resin, molten polypropylene resin, or the like is extruded and laminated, or without coating. In the dry lamination method, an adhesive diluted with an organic solvent to an appropriate viscosity is applied to the coating layer 22, dried, and then a sealant film (resin layer) as the second substrate 23 is laminated by thermocompression. In the non-solvent lamination method, a solventless adhesive is applied to the coating layer 22, and then a sealant film as the second substrate 23 is laminated by thermocompression.

[0116] (base material) Examples of materials for the substrate 11 that can be used in the laminate 10 and the first substrate 21 and second substrate 23 that can be used in the laminate 20 include polyethylenes such as high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE); polypropylene; polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polylactic acid; polyamide (NY); celluloses such as cellophane; polystyrene (PS); ethylene-vinyl acetate copolymer resin; ethylene-vinyl alcohol copolymer resin; polycarbonate; polyimide; polyvinyl chloride; etc. The materials for the substrates 11, 21, and 23 can be selected appropriately depending on the application of the laminates 10 and 20, etc.

[0117] Among the above, polyolefin films such as polyethylenes and polypropylene are preferred as the substrates 11, 21, and 23. It is preferable to use those that have been corona-treated. The substrates 11, 21, and 23 used in the production of the laminates 10 and 20 may all be made from recycled materials that have been used as printed matter and then recovered. The substrates 11, 21, and 23 used in the production of the laminates 10 and 20 may be stretched or unstretched. Furthermore, the substrates 11, 21, and 23 may be, as needed, vapor-deposited with a metal or metal oxide such as silica, alumina, or aluminum, or may have the vapor-deposited surface coated with a paint such as polyvinyl alcohol.

[0118] The shapes of the substrates 11, 21, and 23 are not particularly limited, and substrates of a shape suitable for the purpose can be used. Specific examples of the shape of the substrate include film and sheet shapes. The film- and sheet-shaped substrates 11, 21, and 23 are suitable for use as labels printed with various information such as product names, contents, and manufacturers. Specific examples of the shape of the substrate include various containers and packaging materials such as cups, plates, bowls, and bottles, and lids such as caps. By forming a coating layer using the aqueous coating liquid of this embodiment on the surface of the substrate by a general printing method such as gravure printing or flexographic printing, a laminate can be obtained that has a desired design, information, and the like, and that has excellent substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, as well as transparency.

[0119] (Labels, packaging materials) The laminate of this embodiment is useful as, for example, a label or packaging material. Specifically, the laminate is suitable as containers for storing food products, soft drinks, cosmetics, seasonings, medicines, sanitary products, etc.; labels to be attached to these containers; resin bags (packaging materials) for storing foods such as bread, rice balls, and prepared dishes; etc.

[0120] Label applications include various labels attached to packaging containers for food and beverage products such as beverages, seasonings, prepared dishes, and boxed lunches, cosmetics, and daily necessities. Labels are particularly suitable as labels for products whose packaging containers are plastic bottles, for example, labels for bottled food and beverage products. Examples of bottled food and beverage products include beverages, liquid seasonings (dressings, noodle soup base, soy sauce, liquid miso, etc.), and cooking oil. Labels may be in the form of, for example, wrap labels or shrink labels. Applications for packaging materials include food and beverage products such as confectionery, sweet breads, vegetables, and prepared dishes, daily necessities such as cosmetics, pharmaceuticals, and hygiene products.

[0121] As described above, one embodiment of the present invention can have the following configuration. [1] An aqueous resin composition used in an aqueous coating solution having a coating film haze value of 15% or less, Contains a resin emulsion and a wax, the resin emulsion comprises a polyolefin resin emulsion containing a polyolefin resin having a melting point of 60 to 97°C and an acid value of 13 to 60 mgKOH / g, the wax includes at least one selected from the group consisting of polyethylene-based waxes and paraffin-based waxes, the content of the polyolefin resin is 60 to 95 mass% and the content of the wax is 4 to 25 mass% relative to the mass of the solid content of the aqueous resin composition; The aqueous resin composition, wherein the content of the wax relative to the content of the polyolefin resin is, in mass ratio, polyolefin resin: wax=1:0.043 to 1:0.300. [2] The aqueous resin composition according to [1] above, wherein the polyolefin resin comprises at least one selected from the group consisting of polypropylene resin, polyethylene resin, and polypropylene-polyethylene copolymer. [3] A water dispersion of the polyethylene wax is contained, The aqueous resin composition according to the above [1] or [2], wherein the polyethylene wax has an average particle size of 0.3 to 8 μm. [4] The aqueous resin composition according to any one of the above [1] to [3], wherein the paraffin wax has a melting point of 50 to 120°C. [5] The aqueous resin composition according to any one of the above [1] to [4], wherein the content of the paraffin wax relative to the mass of the solid content of the aqueous resin composition is 0 to 10 mass %. [6] The aqueous resin composition according to any one of the above [1] to [5], further comprising a film-forming aid having a boiling point of 70 to 260°C. [7] The aqueous resin composition according to the above [6], wherein the content of the film-forming aid in the aqueous resin composition is 0.05 to 2.5 in terms of mass ratio to the content of the wax. [8] The aqueous resin composition according to [6] or [7] above, wherein the film-forming aid comprises at least one selected from the group consisting of diethyl diglycol, propylene glycol, dipropylene glycol n-butyl ether, propylene glycol monomethyl ether, isopropyl alcohol, ethanol, and polyethylene glycol. [9] Further, a surfactant is contained, The aqueous resin composition according to any one of the above [1] to [8], wherein the content of the surfactant is 0.01 to 6% by mass relative to the mass of the solid content of the aqueous resin composition.

[10] The resin emulsion further comprises an acrylic resin emulsion containing an acrylic resin having a glass transition temperature of 75°C or higher; The aqueous resin composition according to any one of the above [1] to [9], wherein the content of the acrylic resin in the aqueous resin composition is 35 mass % or less relative to the content of the polyolefin resin.

[11] The resin emulsion further includes a urethane resin emulsion containing a urethane resin, The aqueous resin composition according to any one of the above [1] to

[10] , wherein the content of the urethane resin in the aqueous resin composition is 55 mass % or less relative to the content of the polyolefin resin.

[12] The aqueous resin composition according to any one of the above [1] to

[11] , further comprising at least one selected from the group consisting of a curing agent and a crosslinking agent.

[13] The aqueous resin composition according to any one of the above [1] to

[12] , which has excellent scratch resistance, wherein a coating film obtained by applying the aqueous coating liquid containing the aqueous resin composition is rubbed widthwise with a hard object, and after 10 strokes, the ratio of the area of ​​the coating film that has fallen off to the test area of ​​the coating film is less than 20%.

[14] A solid resin composition obtained by drying the aqueous resin composition according to any one of the above [1] to

[13] .

[15] An aqueous coating solution having a haze value of 15% or less, An aqueous coating liquid containing the aqueous resin composition according to any one of the above [1] to

[13] .

[16] For flexographic or gravure printing, and The aqueous coating liquid according to

[15] above, which is an aqueous varnish, an aqueous medium, an aqueous primer, an aqueous reducer, or an aqueous ink containing a coloring material.

[17] A coating film comprising: a substrate; and a coating layer disposed on the substrate; A laminate comprising a coating layer formed from the aqueous coating liquid described in

[16] above.

[18] The laminate according to the above

[17] , which is a label or packaging material. [Example]

[0122] Hereinafter, one embodiment of the present invention will be specifically described based on examples, but one embodiment of the present invention is not limited to these examples.

[0123] <Preparation of various raw materials> (Polyolefin resin emulsion) Commercially available polyolefin resin emulsions P-1 to P-10 shown in Table 1 below were prepared.

[0124] TIFF0007808718000001.tif80170

[0125] (Other resin emulsions) Commercially available acrylic resin emulsions A-1 to A-4 and urethane resin emulsions U-1 and U-2 shown in Table 2 below were prepared.

[0126] TIFF0007808718000002.tif81170

[0127] (Water dispersion of wax) Commercially available aqueous wax dispersions W-1 to W-8 shown in Table 3 below were prepared.

[0128] TIFF0007808718000003.tif69170

[0129] The following compounds were used as film-forming aids. Diethyldiglycol (hereinafter referred to as DEDG; boiling point 188.9°C) Propylene glycol (hereinafter referred to as "PG"; boiling point 188.2°C) Dipropylene glycol n-butyl ether (hereinafter referred to as "DPnB"; boiling point 230°C) Isopropyl alcohol (hereinafter referred to as "IPA"; boiling point 82.4°C) Propylene glycol monomethyl ether (hereinafter referred to as "PM"; boiling point 121°C) Ethanol (boiling point 78°C) Polyethylene glycol with a number average molecular weight of 200 (hereinafter referred to as "PEG200"; boiling point 250°C)

[0130] Additionally, the following optional ingredients were used: Solvent: Water Pigment: CI Pigment Blue 15:3 (hereinafter also referred to as "PB15:3"; product name "Heliogen Blue D7088", manufactured by BASF Japan Ltd., solid content 100% by mass) Pigment: Titanium oxide (solid content 100% by mass) Surfactant: Non-ionic organic surfactant (product name "TegoWet505", manufactured by BASF Japan) Defoaming agent: BYK-094 (manufactured by BYK Japan, solid content 100% by mass) Thickener: Tafigel PUD45D (manufactured by MUNZING CHEMIE, solid content 40% by mass)

[0131] <Preparation of aqueous resin composition> The components were mixed to obtain mixtures having the compositions (units: parts by mass) shown in the upper rows of Table 4 (Tables 4-1 to 4-7). The resulting mixtures were kneaded using a paint shaker to prepare aqueous resin compositions for each of the Examples and Comparative Examples.

[0132] The "solid content (%)," "polyolefin resin content (%)," and "wax content (%)" shown in the lower part of Table 4 represent the solid content, polyolefin resin, and wax content (% by mass) based on the total mass of the aqueous resin composition, respectively. Furthermore, the content (%) of each component in the solid content, such as the "polyolefin resin content (%) in the solid content" shown in the lower part of Table 4, represents the content (% by mass) of each component based on the solid content of the aqueous resin composition (excluding the pigment, if any). Furthermore, the "coalescence aid / wax" shown in the lower part of Table 4 represents the mass ratio of the coalescence aid content to the wax content in the aqueous resin composition. Similarly, the "acrylic resin content (%) relative to the polyolefin resin content" and the "urethane resin content (%) relative to the polyolefin resin content" represent the ratio (% by mass) of the acrylic resin and urethane resin content to the polyolefin resin content in the aqueous resin composition, respectively.

[0133] TIFF0007808718000004.tif246170

[0134] TIFF0007808718000005.tif245170

[0135] TIFF0007808718000006.tif246170

[0136] TIFF0007808718000007.tif245170

[0137] TIFF0007808718000008.tif230170

[0138] TIFF0007808718000009.tif229170

[0139] TIFF0007808718000010.tif229170

[0140] <Preparation of aqueous coating liquid and production of laminate> (Water-based coating liquid and laminate G for gravure printing) Each aqueous resin composition was diluted with a diluting solvent (water) to a viscosity of 25 seconds at 25°C measured using a Zahn cup #3 to prepare an aqueous coating solution for printing. Using a gravure printing machine (product name "K Printing Proofer," manufactured by Matsuo Sangyo Co., Ltd.) equipped with a Helio 250 lines / inch gravure engraving plate, the prepared aqueous coating solution was gravure printed onto the treated surface of the substrate shown below, followed by drying at 25°C for 24 hours to form a printed layer. In this way, each aqueous resin composition (each aqueous coating solution) was used to obtain a laminate G (see FIG. 1), which is a printed product comprising a substrate and a printed layer provided on the substrate.

[0141] (Water-based coating liquid and laminate F for flexographic printing) Each aqueous resin composition prepared was diluted with water so that the viscosity at 25°C measured using a Zahn cup #4 was 20 seconds, to prepare an aqueous coating liquid for printing. Using an anilox roll with a cell volume of 6 cc, the prepared aqueous coating liquid was printed by flexography on the treated surface of the substrate shown below, and then dried at 25°C for 24 hours to form a printed layer. In this way, each aqueous resin composition (each aqueous coating liquid) was used to obtain Laminate F (see Figure 1), which is a printed product comprising a substrate and a printed layer provided on the substrate.

[0142] For the laminate G and laminate F, the following substrates were used. OPP: OPP film with one side corona discharge treated (product name "FOR", manufactured by Futamura Chemical Co., Ltd., thickness 30 μm) PET: PET film with one side corona discharge treated (product name "Ester Film 8102", manufactured by Toyobo Co., Ltd., thickness 12 μm) PS: PS film with one side corona discharge treated (product name "GMGS", manufactured by Gunze Co., Ltd., thickness 50 μm)

[0143] <Laminate film manufacturing> For Examples 8 to 12 and 17, laminate G was produced in the same manner as described above, and then a dry laminating adhesive (product name "Seikabond E372 / C-76", manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.) was applied to the printed layer of laminate G (the surface opposite to the substrate) in a dry coating amount of 3 g / m. 2 An adhesive layer was formed by gravure printing so that the pattern was as follows. Next, an LLDPE film (product name "TUX HC", manufactured by Mitsui Chemicals Tocello, Inc., thickness 60 μm) was thermocompressed onto the adhesive layer as a second substrate. After that, aging was carried out at 40°C for 48 hours. In this way, a laminate film (see Figure 2) was obtained, which was a printed material in which the first substrate (OPP or PET), printed layer, adhesive layer, and second substrate (LLDPE) were laminated in this order.

[0144] <Evaluation> The fluidity and storage stability of each aqueous resin composition in the Examples and Comparative Examples, as well as the substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, scratch resistance, and haze of the coating layer (printed layer) in the laminate (printed material) were evaluated as follows. The evaluation results are shown in Table 5 (Tables 5-1 to 5-7).

[0145] (Liquidity) After each aqueous resin composition was produced, it was stored at 25°C for 24 hours, and then the fluidity was visually confirmed and evaluated according to the following evaluation criteria. Good: Good fluidity. △: Thixotropy is observed and fluidity is partially impaired. ×: No fluidity.

[0146] (Storage stability) After each aqueous resin composition was produced, it was stored in a thermo-hygrostat at a cycle of 0°C to 40°C for one month, and then the fluidity was visually inspected and evaluated according to the following evaluation criteria. Good: Good fluidity. △: Some liquidity is impaired. ×: No fluidity.

[0147] (Adhesion to substrate) After attaching cellophane tape (manufactured by Nichiban Co., Ltd.) to the printed layer of the prepared laminate F, the cellophane tape was quickly peeled off, and the condition of the printed layer remaining on the substrate film was visually inspected, and the adhesion of the printed layer to the substrate was evaluated according to the evaluation criteria shown below. 5: The printing layer has not peeled off at all. 4: The ratio of the area of ​​the peeled printed layer to the adhesive area of ​​the cellophane tape (peeling ratio) is more than 0% and less than 20%. 3: The ratio of the area of ​​the peeled printed layer to the adhesive area of ​​the cellophane tape (peeling ratio) is 20% or more and less than 50%. 2: The ratio of the area of ​​the peeled printed layer to the adhesive area of ​​the cellophane tape (peeling ratio) is 50% or more and less than 70%. 1: The ratio of the area of ​​the peeled printed layer to the adhesive area of ​​the cellophane tape (peeling ratio) is 70% or more and less than 100%.

[0148] (blocking resistance) The printed layer of the prepared laminate F was placed on the non-printed side of the same base film, and the resulting laminate was subjected to a spring-type blocking test (OPP: 4 kgf / cm 3 PET: 7kgf / cm 3 ) and stored at a temperature of 40°C for 24 hours. After storage, the base film was peeled off from the printed layer of Laminate F, and the state of the printed layer transferred to the non-printed surface of the base film was visually inspected, and the blocking resistance of the printed layer (retention of the printed layer) was evaluated according to the evaluation criteria shown below. 5: The printed layer is not transferred to the non-printed surface of the base film. 4: The ratio of the area of ​​the printed layer transferred to the non-printed surface to the area of ​​the overlapping printed layer and the non-printed surface of the base film is more than 0% and less than 20%. 3: The ratio of the area of ​​the printed layer transferred to the non-printed surface to the area of ​​the overlapping printed layer and the non-printed surface of the base film is 20% or more and less than 50%. 2: The ratio of the area of ​​the printed layer transferred to the non-printed surface to the area of ​​the overlapping printed layer and the non-printed surface of the base film is 50% or more and less than 70%. 1: The ratio of the area of ​​the printed layer transferred to the non-printed surface to the area of ​​the overlapping printed layer and the non-printed surface of the base film is 70% or more but less than 100%.

[0149] (Heat seal blocking resistance) The printed layer of the prepared laminate F was superimposed on a 100 μm-thick untreated PET film (product name "Ester Film E5000", manufactured by Toyobo Co., Ltd.), and pressure-bonded using a heat seal tester (product name "TP-701-C", manufactured by Tester Sangyo Co., Ltd.) at 90°C, 0.3 MPa, and for 3 minutes. After pressure-bonding, the PET film was peeled off from the printed layer of laminate F, and the state of the printed layer transferred to the PET film was visually confirmed. The heat seal blocking resistance (heat resistance) of the printed layer was evaluated according to the following evaluation criteria. 5: The printed layer is not transferred to the PET film. 4: The ratio of the area of ​​the printed layer transferred to the PET film to the area of ​​the pressed printed layer is more than 0% and less than 20%. 3: The ratio of the area of ​​the printed layer transferred to the PET film to the area of ​​the pressure-bonded printed layer is 20% or more and less than 50%. 2: The ratio of the area of ​​the printed layer transferred to the PET film to the area of ​​the pressure-bonded printed layer is 50% or more and less than 70%. 1: The ratio of the area of ​​the printed layer transferred to the PET film to the area of ​​the pressure-bonded printed layer is 70% or more but less than 100%.

[0150] (hot melt adhesive) The printed layer of the prepared laminate F and a 100 μm thick PET film coated with a hot melt adhesive using a coater were placed between the hot melt adhesive layer and sealed using a heat seal tester (product name "TP-701-C", manufactured by Tester Sangyo Co., Ltd.) at 90 ° C, 0.2 MPa, and 1 second to prepare 10 mm wide strip-shaped test pieces. Using a universal tensile tester (product name "E3-L", manufactured by Toyo Seiki Seisakusho Co., Ltd.), the prepared test pieces were subjected to tensile peeling (T-peel) at a tensile speed of 300 mm / min, and the average load at peeling was measured. The hot melt adhesive properties of the printed layer were then evaluated according to the following evaluation criteria. 5: The average load during peeling is 6.0 N / 10 mm or more. 4: The average load at the time of peeling is 4.5 N / 10 mm or more and less than 6.0 N / 10 mm. 3: The average load at the time of peeling is 3.0 N / 10 mm or more and less than 4.5 N / 10 mm. 2: The average load at the time of peeling is 1.5 N / 10 mm or more and less than 3.0 N / 10 mm. 1: The average load at the time of peeling is less than 1.5 N / 10 mm.

[0151] (scratch resistance) The printed layer of the prepared laminate F was rubbed with a fingernail in the width direction 10 times, after which the condition of the printed layer was visually inspected, and the scratch resistance of the printed layer was evaluated according to the evaluation criteria shown below. 5: No falling off of the printed layer. 4: The percentage of the area of ​​the printed layer that has fallen off is greater than 0% and less than 20% of the test area of ​​the printed layer. 3: The ratio of the area of ​​the fallen printed layer to the test area of ​​the printed layer is 20% or more but less than 50%. 2: The ratio of the area of ​​the fallen printed layer to the test area of ​​the printed layer is 50% or more but less than 70%. 1: The ratio of the area of ​​the fallen printed layer to the test area of ​​the printed layer is 70% or more but less than 100%.

[0152] (Hayes) The haze (%) of the prepared laminate F was measured using a haze computer (product name "H2-2P", manufactured by Suga Test Instruments Co., Ltd.) in accordance with the provisions of JIS K-7136 (single beam, C light source measurement). The haze (%) of the same substrate as that used for laminate F was measured using the same method, and the haze value of the substrate was subtracted from the haze value of laminate F to obtain the haze (%) of the printed layer. The haze (%) of the printed layer was then evaluated according to the evaluation criteria shown below. 5: The haze of the printed layer is 10% or less. 4: The haze of the printed layer is more than 10% and 15% or less. 3: The haze of the printed layer is more than 15% and less than 20%. 2: The haze of the printed layer is more than 20% and 25% or less. 1: The haze of the printed layer is more than 25%.

[0153] (dry laminate strength) The laminate film was cut into strip-shaped test pieces 15 mm wide. Using a universal tensile tester (product name "E3-L" manufactured by Toyo Seiki Seisakusho, Ltd.), the test pieces were subjected to tensile peeling (T-peel) at a tensile speed of 300 mm / min, and the average load during peeling was measured. The dry laminate strength was then evaluated according to the following evaluation criteria. The evaluation results are shown in Table 6. 5: The average load during peeling is 2.0 N / 15 mm or more. 4: The average load at the time of peeling is 1.6 N / 15 mm or more and less than 2.0 N / 15 mm. 3: The average load at the time of peeling is 1.2 N / 15 mm or more and less than 1.6 N / 15 mm. 2: The average load at the time of peeling is 0.8 N / 15 mm or more and less than 1.2 N / 15 mm. 1: The average load at the time of peeling is less than 0.8 N / 15 mm.

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[0162] As shown in the results in Table 5, the aqueous resin compositions of Examples 1 to 29 had good fluidity and storage stability. Furthermore, by using the aqueous resin compositions of the Examples, aqueous coating solutions capable of forming coating layers (printed layers) that had good substrate adhesion, blocking resistance, heat seal blocking resistance, hot melt adhesive properties, and scratch resistance, as well as transparency, were obtained.

[0163] Furthermore, as shown in the results in Table 6, by using the aqueous resin compositions of Examples 8 to 12 and 17, aqueous coating solutions capable of forming coating layers (printed layers) with moderately high dry laminate strength were obtained, thereby resulting in laminate films with high dry laminate strength.

[0164] (Application example 1) Laminates (Laminates G-2 and F-2, respectively) having a second printed layer were produced by printing an aqueous coating liquid using the same aqueous resin composition as in Examples 1 to 29 on the printed layer (first coated layer) in Laminates G and F of Examples 1 to 29 using the same printing method as for the first coated layer. The second coated layers in Laminates G-2 and F-2 also gave results similar to those obtained in Examples 1 to 29, in which the first coated layer was evaluated.

[0165] (Application example 2) Examples 10 to 13, which used polyethylene wax, and Examples 14 to 16, which used paraffin wax, were compared and examined, dividing them into cases where the coating layer was the outermost layer (surface printing) and where the substrate was the outermost layer (reverse printing). Examples 10 to 13, which used polyethylene wax, were superior in reverse printing from the standpoints of blocking resistance and dry lamination strength, while Examples 14 to 16, which used paraffin wax, were superior in front printing from the standpoints of heat seal resistance and scratch resistance.

Claims

1. An aqueous resin composition used in an aqueous coating solution for plastic films that forms a coating film having a haze value of 15% or less as measured in accordance with the provisions of JIS K-7136, Contains a resin emulsion and a wax, the resin emulsion comprises a polyolefin resin emulsion containing a polyolefin resin having a melting point of 60 to 97°C and an acid value of 13 to 60 mgKOH / g; the wax includes at least one selected from the group consisting of polyethylene-based waxes and paraffin-based waxes, the content of the polyolefin resin is 60 to 95% by mass and the content of the wax is 4 to 25% by mass relative to the mass of the solid content of the aqueous resin composition; The aqueous resin composition, wherein the content of the wax relative to the content of the polyolefin resin is, in mass ratio, polyolefin resin: wax=1:0.043 to 1:0.

300.

2. 2. The aqueous resin composition according to claim 1, wherein the polyolefin resin comprises at least one selected from the group consisting of polypropylene resin, polyethylene resin, and polypropylene-polyethylene copolymer.

3. containing the polyethylene wax in water, 2. The aqueous resin composition according to claim 1, wherein the polyethylene wax has an average particle size of 0.3 to 8 μm.

4. 2. The aqueous resin composition according to claim 1, wherein the paraffin wax has a melting point of 50 to 120°C.

5. 2. The aqueous resin composition according to claim 1, wherein the content of the paraffin wax relative to the mass of the solid content of the aqueous resin composition is 0 to 10 mass %.

6. 2. The aqueous resin composition according to claim 1, further comprising a film-forming aid having a boiling point of 70 to 260°C.

7. 7. The aqueous resin composition according to claim 6, wherein the content of the film-forming aid in the aqueous resin composition is 0.05 to 2.5 in terms of mass ratio to the content of the wax.

8. 7. The aqueous resin composition according to claim 6, wherein the film-forming aid comprises at least one selected from the group consisting of diethyl diglycol, propylene glycol, dipropylene glycol n-butyl ether, propylene glycol monomethyl ether, isopropyl alcohol, ethanol, and polyethylene glycol.

9. Further, it contains a surfactant, 2. The aqueous resin composition according to claim 1, wherein the content of the surfactant is 0.01 to 6% by mass relative to the mass of the solid content of the aqueous resin composition.

10. the resin emulsion further comprises an acrylic resin emulsion containing an acrylic resin having a glass transition temperature of 75°C or higher; 2. The aqueous resin composition according to claim 1, wherein the content of the acrylic resin in the aqueous resin composition is 35% by mass or less relative to the content of the polyolefin resin.

11. the resin emulsion further comprises a urethane resin emulsion containing a urethane resin, 2. The aqueous resin composition according to claim 1, wherein the content of the urethane resin in the aqueous resin composition is 55% by mass or less relative to the content of the polyolefin resin.

12. The aqueous resin composition according to claim 1, further comprising at least one selected from the group consisting of a curing agent and a crosslinking agent.

13. 2. The aqueous resin composition according to claim 1, wherein the coating film obtained by applying the aqueous coating liquid containing the aqueous resin composition is rubbed in the width direction with a hard object, and after 10 reciprocating strokes, the ratio of the area of ​​the coating film that has fallen off to the test area of ​​the coating film is less than 20%.

14. An aqueous coating solution for plastic films that forms a coating film having a haze value of 15% or less as measured in accordance with the provisions of JIS K-7136, An aqueous coating liquid for plastic films, comprising the aqueous resin composition according to any one of claims 1 to 13.

15. for flexographic or gravure printing, and 15. The aqueous coating liquid for plastic films according to claim 14, which is an aqueous varnish, an aqueous medium, an aqueous primer, an aqueous reducer, or an aqueous ink containing a coloring material.

16. A substrate and a coating layer disposed on the substrate, the substrate is a plastic film, A laminate comprising a coating layer formed from the aqueous coating liquid for plastic films according to claim 15.

17. The laminate according to claim 16, which is a label or packaging material.

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