Aqueous coating agents and laminates

Abstract

The present invention provides an aqueous coating agent that exhibits excellent adhesion to various substrates, provides excellent release properties of the adherend in a temperature environment close to room temperature, and can form a release layer that maintains excellent release properties even after heat treatment at temperatures exceeding the aforementioned temperature. [Solution] The aqueous coating agent of the present invention contains an acid-modified polyolefin resin (A), an acrylic resin having a long-chain alkyl group (B), and an aqueous medium (C), wherein the content of the acrylic resin having a long-chain alkyl group (B) is 20 to 60 parts by mass per 100 parts by mass of the acid-modified polyolefin resin (A).

Description

Technical Field

[0001] The present invention relates to an aqueous coating agent and a laminate.

Background Art

[0002] Adhesive tapes (or adhesive sheets) are used in various scenarios including the manufacturing processes of electronic components such as semiconductor devices and precision instruments. Until use, a release sheet is laminated on the adhesive surface of such an adhesive tape for the purpose of protecting the adhesive surface.

[0003] The release sheet has a configuration in which a release layer for facilitating peeling from the adhesive tape is provided on the surface of the base material. Conventionally, silicone-based release agents have been widely used for such release layers. However, when a release sheet containing a silicone-based release agent in the release layer is used for an adhesive tape, low-molecular-weight silicone compounds contained in the silicone-based release agent may migrate to the adhesive surface of the adhesive tape and contaminate the adhesive tape. And when an adhesive tape contaminated with a low-molecular-weight silicone compound is used for an electronic component, it is known that low-molecular siloxane causes contact failure of the electronic component. Therefore, using a non-silicone-based release agent for the resin layer of the release sheet has been under consideration.

[0004] Patent Document 1 describes a release film obtained by applying a coating solution obtained by dissolving an acrylic resin containing a long-chain alkyl group as a non-silicone-based release resin in a solvent to the surface of a base material film and drying by heating.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, the release film described in Patent Document 1 was not entirely satisfactory in terms of release properties after heat treatment and the residual adhesion rate of the adhesive tape after peeling it off the release film. With the increasing complexity of electronic component manufacturing processes, it is becoming necessary to apply adhesive tape to a release layer of a release sheet and then subject it to processes such as pressing and infrared / UV irradiation. Since these processes include heat treatment, the release layer of the release sheet to which the adhesive tape is attached is also exposed to high temperatures. Therefore, the release layer is required to have the same degree of release properties after heat treatment as before heat treatment (i.e., the property of being able to peel off with the same strength as before heat treatment). In particular, for release sheets that have release layers on both sides of the substrate, release properties after heat treatment are essential. By setting the peel strength so that each release layer formed on both sides of the substrate exhibits release properties at different temperatures, it becomes possible to exhibit the release properties of any of the two release layers during the manufacturing process and accurately peel off only the laminate of that release layer. If the peel strength changes due to heat treatment or over time, peel control becomes difficult, and unintended peeling may lead to failure of the production machine. Furthermore, if a release sheet is attached to adhesive tape and then peeled off, the components of the release sheet can transfer to the adhesive tape, causing poor adhesion of the tape.

[0007] Therefore, the object of the present invention is to provide an aqueous coating agent that has excellent adhesion to various substrates, excellent release properties of the adherend in a temperature environment close to room temperature (5 to 40°C), and can form a coating film that maintains excellent release properties even after heat treatment at temperatures exceeding the aforementioned temperature. Another object of the present invention is to provide an aqueous coating agent capable of forming a coating film that has excellent release properties for the adherend and can maintain a high residual adhesion rate of the adhesive tape that is the adherend (i.e., the adhesion rate of the adhesive surface of the adhesive tape or adhesive sheet after peeling it off after being attached to the coating film). Another object of the present invention is to provide a laminate that exhibits excellent adhesion to various substrates, has excellent release properties of the adherend in a temperature environment close to room temperature (5 to 40°C), and maintains excellent release properties even after heat treatment at temperatures exceeding the aforementioned temperature. Another object of the present invention is to provide a laminate that exhibits excellent release properties of the adherend and can maintain a high residual adhesion rate of the adhesive tape that is the adherend. [Means for solving the problem]

[0008] The inventors of this invention conducted intensive research to solve the above problems and found that an aqueous coating agent obtained by mixing a specific amount of an acrylic resin having a long-chain alkyl group with an acid-modified polyolefin resin can solve the above problems. The present invention was completed based on these findings.

[0009] In other words, the present invention comprises an acid-modified polyolefin resin (A), an acrylic resin having a long-chain alkyl group (B), and an aqueous medium (C). The present invention provides an aqueous coating agent in which the content of an acrylic resin (B) having a long-chain alkyl group is 20 to 60 parts by mass per 100 parts by mass of an acid-modified polyolefin resin (A).

[0010] The present invention also relates to a laminate comprising a coating film on part or all of at least one surface of a substrate layer, The present invention provides a laminate in which the coating film contains an acid-modified polyolefin resin (A) and an acrylic resin (B) having a long-chain alkyl group, wherein the content of the acrylic resin (B) having a long-chain alkyl group is 20 to 60 parts by mass per 100 parts by mass of the acid-modified polyolefin resin (A).

[0011] The present invention also provides a laminate in which the base layer is a thermoplastic resin film or a metal foil. [Effects of the Invention]

[0012] The coating film obtained from the aqueous coating agent of the present invention exhibits excellent adhesion to the substrate, release properties of the adherend, and release properties after heat treatment. Therefore, it can be suitably used as a material for forming release layers such as release films and release sheets used in processes that include heat treatment. [Modes for carrying out the invention]

[0013] [Water-based coating agent] The aqueous coating agent of the present invention contains an acid-modified polyolefin resin (A), an acrylic resin having a long-chain alkyl group (B), and an aqueous medium (C).

[0014] (Acid-modified polyolefin resin (A)) The acid-modified polyolefin resin (A) is obtained by acid-modifying a polyolefin resin with an unsaturated carboxylic acid.

[0015] The acid-modified polyolefin resin (A) has a structure in which at least an olefin and an unsaturated carboxylic acid are copolymerized. The form of the copolymerization is not limited and includes, for example, random copolymerization, radical copolymerization, block copolymerization, graft copolymerization, etc.

[0016] Examples of the olefins include alkenes such as ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, and 1-octene (for example, alkenes having 2 to 10 carbon atoms); and cycloalkenes such as norbornene. These can be used individually or in combination of two or more. In the present invention, alkenes having 2 to 6 carbon atoms, such as ethylene, propylene, isobutylene, 1-butene, 1-pentene, and 1-hexene, are preferred, alkenes having 2 to 4 carbon atoms, such as ethylene, propylene, isobutylene, and 1-butene, are more preferred, and ethylene and / or propylene are even more preferred.

[0017] Examples of the unsaturated carboxylic acid include unsaturated mono- or dicarboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, fumaric acid, and crotonic acid; unsaturated carboxylic acid anhydrides such as maleic anhydride and itaconic anhydride; half esters, half amides, etc. of the unsaturated dicarboxylic acid. In the present invention, among them, at least one selected from acrylic acid, methacrylic acid, maleic acid, and maleic anhydride is preferable, and acrylic acid and / or maleic anhydride are more preferable.

[0018] From the viewpoint of improving the adhesion to the substrate, the proportion of the constituent unit derived from olefin in the total amount of the constituent units constituting the acid-modified polyolefin resin (A) is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, and particularly preferably 90% or more. The upper limit value of the proportion is, for example, 99% by mass.

[0019] From the viewpoints of improving the releasability and the adhesion to the substrate, the proportion of the constituent unit derived from unsaturated carboxylic acid in the total amount of the constituent units constituting the acid-modified polyolefin resin (A) is preferably 0.1 to 25% by mass, more preferably 0.5 to 15% by mass, still more preferably 1 to 8% by mass, and particularly preferably 1 to 5% by mass.

[0020] The acid-modified polyolefin resin (A) may contain other constituent units in addition to the constituent unit derived from olefin and the constituent unit derived from unsaturated carboxylic acid. From the reason of improving the adhesion to the thermoplastic resin substrate, it is preferable to contain a constituent unit derived from (meth)acrylate.

[0021] Examples of the (meth)acrylic acid ester include ester compounds of (meth)acrylic acid and an alcohol having 1 to 30 carbon atoms. In the present invention, from the viewpoint of easy availability, ester compounds of (meth)acrylic acid and an alcohol having 1 to 20 carbon atoms are preferred. Specific examples of the ester compound include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, octyl (meth)acrylate, dodecyl (meth)acrylate, stearyl (meth)acrylate and the like. These can be used alone or in combination of two or more. In the present invention, among them, from the viewpoint of improving the adhesion to the base film, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl (meth)acrylate, octyl (meth)acrylate are more preferred, ethyl (meth)acrylate and butyl (meth)acrylate are more preferred, and ethyl (meth)acrylate is particularly preferred. In this specification, "(meth)acrylic acid" means "acrylic acid" and "methacrylic acid".

[0022] From the viewpoints of improving the releasability and the adhesion to the base material, the proportion of the constituent unit derived from the (meth)acrylic acid ester in the total amount of the constituent units constituting the acid-modified polyolefin resin (A) is preferably 0.5 to 40% by mass, more preferably 1 to 35% by mass, still more preferably 3 to 30% by mass, still more preferably 3 to 20% by mass, particularly preferably 3 to 15% by mass, and most preferably 3 to 10% by mass.

[0023] The acid-modified polyolefin resin (A) may also contain one or more constituent units derived from other monomers in addition to the above-mentioned constituent units. Examples of other monomers include dienes; maleic acid esters such as dimethyl maleate, diethyl maleate, and dibutyl maleate; (meth)acrylamides; alkyl vinyl ethers such as methyl vinyl ether and ethyl vinyl ether; vinyl esters such as vinyl formate, vinyl acetate, vinyl propionate, vinyl pivalate, and vinyl versatate; vinyl alcohols obtained by saponifying the vinyl esters with a basic compound; 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, (meth)acrylonitrile, styrene, substituted styrene, carbon monoxide, sulfur dioxide, etc. The content of constituent units derived from other monomers is, for example, 10% by mass or less of the total amount of constituent units of the modified polyolefin resin (A).

[0024] As the acid-modified polyolefin resin (A), at least one selected from ethylene-(meth)acrylic acid copolymer resin, ethylene-(meth)acrylic acid ester-maleic anhydride copolymer resin, ethylene-maleic anhydride copolymer resin, ethylene-propylene-butene-maleic anhydride copolymer resin, propylene-maleic anhydride copolymer resin, propylene-butene-maleic anhydride copolymer resin, α-olefin-ethylene-maleic anhydride copolymer resin, α-olefin-ethylene-(meth)acrylic acid copolymer resin, etc. is preferred. The polyolefin resin may be chlorinated in the range of 5 to 40% by mass.

[0025] When the acid-modified polyolefin resin (A) contains ethylene-derived constituent units (A2) and (meth)acrylic acid ester-derived constituent units (A3), the total content of the constituent units (A2) and (A3) is preferably 99 to 85% by mass of the total amount of constituent units constituting the acid-modified polyolefin resin (A), and more preferably 98 to 95% by mass.

[0026] When the acid-modified polyolefin resin (A) contains constituent units (A2) derived from ethylene and constituent units (A3) derived from (meth)acrylic acid ester, the mass ratio (A2) / (A3) of the constituent units (A2) to (A3) is preferably 55 / 45 to 96 / 4, and more preferably 80 / 20 to 95 / 5.

[0027] The melt flow rate of the acid-modified polyolefin resin (A) (at 190°C and a 2160g load) is not particularly limited, but from the viewpoint of improving release properties and adhesion to the substrate, it is preferably 0.01 to 9000 g / 10 min, more preferably 0.1 to 5000 g / 10 min, more preferably 1 to 500 g / 10 min, even more preferably 2 to 300 g / 10 min, and particularly preferably 2 to 200 g / 10 min.

[0028] The melting point of the acid-modified polyolefin resin (A) is not particularly limited, but it is preferably 150°C or lower from the viewpoint of substrate adhesion and haze.

[0029] The weight-average molecular weight of the acid-modified polyolefin resin (A) is not particularly limited, but is preferably 2000 or more, more preferably 5000 or more, and especially preferably 10000 or more, from the viewpoint of substrate adhesion and release properties after heat treatment. The upper limit of the weight-average molecular weight is, for example, 1 million, and preferably 500,000.

[0030] Commercially available products can be used as the acid-modified polyolefin resin (A). Examples of commercially available products include Bondine HX-8290, TX-8030, and HX-8210 from Arkema Corporation, and A-5515, A-5260, and A-5320H from the Lucant series from Mitsui Chemicals, Inc.

[0031] The acid-modified polyolefin resin (A) can be used as an aqueous dispersion by dispersing it in an aqueous medium. In this case, the number-average particle size (mn) of the acid-modified polyolefin resin (A) in the aqueous dispersion is, for example, 5 to 500 nm. The lower limit of the number-average particle size is preferably 7 nm, more preferably 10 nm, more preferably 15 nm, even more preferably 40 nm, even more preferably 60 nm, particularly preferably 70 nm, and most preferably 75 nm, from the viewpoint of improving release properties and adhesion to the substrate. The upper limit of the number-average particle size is preferably 300 nm, more preferably 200 nm, even more preferably 100 nm, particularly preferably 90 nm, and most preferably 80 nm.

[0032] The weight-average particle size (mw) of the acid-modified polyolefin resin (A) in an aqueous dispersion is, for example, 5 to 800 nm. The lower limit of the number-average particle size is preferably 10 nm, more preferably 30 nm, more preferably 50 nm, even more preferably 80 nm, and even more preferably 95 nm, from the viewpoint of improving release properties and adhesion to the substrate. The upper limit of the number-average particle size is preferably 500 nm, more preferably 300 nm, even more preferably 200 nm, and particularly preferably 110 nm.

[0033] (Acrylic resin having long-chain alkyl groups (B)) Acrylic resin (B) having long-chain alkyl groups (hereinafter sometimes simply referred to as "long-chain alkyl-containing acrylic resin (B)") is an acrylic resin having long-chain alkyl groups in its side chains and / or terminals.

[0034] The long-chain alkyl-containing acrylic resin (B) may be a polymer obtained by homopolymerization or copolymerization of (meth)acrylic acid monomers having long-chain alkyl groups, or it may be a graft polymer in which long-chain alkyl groups are graft polymerized, or a block polymer in which long-chain alkyl groups are added to the terminals.

[0035] The long-chain alkyl-containing acrylic resin (B) contains at least one structural unit derived from a (meth)acrylic acid monomer having a long-chain alkyl group. The content of the structural unit derived from the (meth)acrylic acid monomer having a long-chain alkyl group is, for example, 50% by mass or more of the total amount of structural units constituting the long-chain alkyl-containing acrylic resin (B).

[0036] The long-chain alkyl group in the long-chain alkyl-containing acrylic resin (B) has, for example, 6 or more carbon atoms, preferably 10 or more, and more preferably 14 or more carbon atoms. The upper limit of the carbon number is, for example, 25, preferably 22. The long-chain alkyl group includes both linear and branched long-chain alkyl groups.

[0037] Examples of the long-chain alkyl groups include linear or branched long-chain alkyl groups such as hexyl, octyl, decyl, lauryl, octadecyl, behenyl, myristyl, palmityl, stearyl, and isostearyl groups.

[0038] Examples of (meth)acrylic acid monomers having long-chain alkyl groups include octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, octadecyl (meth)acrylate, behenyl (meth)acrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, and isostearyl (meth)acrylate. These can be contained individually or in combination of two or more.

[0039] The long-chain alkyl-containing acrylic resin (B) may also have constituent units derived from other monomers in addition to the aforementioned constituent units.

[0040] Other monomers include, for example, alkenyl (meth)acrylate esters having a double bond group, alkyl (meth)acrylate esters having an alkyl group with 5 or fewer carbon atoms, and monomers having a hydroxyl group in the molecule (hydroxyl group-containing monomers).

[0041] Examples of (meth)acrylate alkenyl esters having a double bond include oleyl (meth)acrylate, erucyl (meth)acrylate, eleostearyl (meth)acrylate, and elaidyl (meth)acrylate.

[0042] Examples of alkyl (meth)acrylate esters having an alkyl group with 5 or fewer carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, and n-hexyl (meth)acrylate. These can be contained individually or in combination of two or more.

[0043] The weight-average molecular weight of the long-chain alkyl-containing acrylic resin (B) is preferably between 10,000 and 1,000,000.

[0044] As the long-chain alkyl-containing acrylic resin (B), an aqueous dispersion is preferred due to its excellent dispersion stability. The volume-average particle size (mv) in water is preferably 50 to 1000 nm, more preferably 100 to 900 nm, and even more preferably 200 to 800 nm. The particle size can be measured using dynamic light scattering.

[0045] Furthermore, as for the long-chain alkyl-containing acrylic resin (B), from the viewpoint of obtaining a coating film with excellent mold release properties, the volume-average particle size (mv) is preferably 200 to 500 nm, more preferably 200 to 400 nm, and even more preferably 250 to 350 nm.

[0046] Furthermore, as for the long-chain alkyl-containing acrylic resin (B), from the viewpoint of improving the residual adhesion rate of the adhesive tape that is the adherend, the volume-average particle diameter (mv) is preferably 300 to 800 nm, more preferably 400 to 800 nm, even more preferably 500 to 800 nm, and particularly preferably 600 to 800 nm.

[0047] (Aqueous medium (C)) The aqueous medium is a medium whose main component is water, and may contain a water-soluble organic solvent from the viewpoint of improving the dispersibility of the acid-modified polyolefin resin (A).

[0048] A water-soluble organic solvent is an organic solvent whose solubility in water at 20°C is, for example, 20 g / L or more, and an organic solvent with a solubility of 100 g / L or more at 20°C is preferred.

[0049] Specific examples of organic solvents include alcohols such as methanol, ethanol, n-propanol, isopropanol (IPA), and n-butanol; ketones such as methyl ethyl ketone and cyclohexanone; ethers such as tetrahydrofuran and dioxane; and glycol monoethers such as ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether. Among these, alcohols are preferred from the viewpoint of low-temperature drying properties, and at least one selected from ethanol, isopropanol (IPA), and n-propanol is particularly preferred.

[0050] When an organic solvent is included, its content is preferably 1 to 40 parts by mass, more preferably 2 to 30 parts by mass, and particularly preferably 3 to 20 parts by mass, based on 100 parts by mass of the total of the solids (for example, acid-modified polyolefin resin (A) and long-chain alkyl-containing acrylic resin (B)) and water.

[0051] (others) The aqueous coating agent of the present invention may contain components other than those listed above, if necessary. These components may include, for example, crosslinking agents, polymers other than those listed in (A) and (B), pigments, dyes, antistatic agents, leveling agents, defoaming agents, anti-smearing agents, thickeners, pigment dispersants, ultraviolet absorbers, and other additives. Furthermore, the aqueous coating agent of the present invention may also contain organic or inorganic compounds other than those listed above, as long as this does not impair its storage stability.

[0052] Examples of crosslinking agents include self-crosslinking compounds, compounds having multiple functional groups in the molecule that react with carboxyl groups contained in the acid-modified polyolefin resin (A), and metal complexes having polyvalent coordination sites. Examples of crosslinking agents include melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, oxazoline compounds, isocyanate compounds, zirconium salt compounds, silane coupling agents, and titanate coupling agents. These can be contained individually or in combination of two or more. In the present invention, epoxy compounds, oxazoline compounds, isocyanate compounds, and titanate coupling agents are preferred, with oxazoline compounds being more preferred.

[0053] The crosslinking agent content is 0.1 to 50 parts by mass, preferably 0.5 to 30 parts by mass, per 100 parts by mass of acid-modified polyolefin resin (A), from the viewpoint of improving chemical resistance, release properties, and the residual adhesion rate of the adhesive tape that is adhered to.

[0054] The crosslinking agent content is, for example, 0.1 parts by mass or more per 100 parts by mass of acid-modified polyolefin resin (A), preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 3 parts by mass or more, from the viewpoint of improving chemical resistance. The upper limit of the crosslinking agent content is, for example, 20 parts by mass, preferably 15 parts by mass, more preferably 10 parts by mass, and even more preferably 8 parts by mass, from the viewpoint of improving release properties.

[0055] Examples of polymers other than those described in (A) and (B) above include polyvinyl acetate, ethylene-vinyl acetate copolymer, polyvinyl chloride, polyvirinidene chloride, ethylene-(meth)acrylic acid copolymer, styrene-maleic acid resin, styrene-butadiene resin, butadiene resin, acrylonitrile-butadiene resin, poly(meth)acrylonitrile resin, (meth)acrylamide resin, chlorinated polyethylene resin, chlorinated polypropylene resin, polyester resin, urethane resin (polyether type, polyester type, polycarbonate type), modified nylon resin, phenolic resin, silicone resin, epoxy resin, etc. These can be contained individually or in combination of two or more. These can be added to aqueous coating agents in a dispersed state in water or dissolved in a solution. Alternatively, two or more may be used in combination.

[0056] Examples of pigments include inorganic pigments such as titanium dioxide, zinc oxide, chromium oxide, cadmium sulfide, calcium carbonate, barium carbonate, barium sulfate, clay, talc, lead yellow, iron oxide, and carbon black; and organic pigments such as azo, diazo, condensed azo, thioindigo, indanthrone, quinacridone, anthraquinone, benzimidazole, perylene, perinone, phthalocyanine, halogenated phthalocyanine, anthrapyridine, and dioxazine. These can be included individually or in combination of two or more.

[0057] Examples of dyes include direct dyes, reactive dyes, acid dyes, cationic dyes, vat dyes, and mordant dyes. These can be included individually or in combination of two or more.

[0058] Examples of antistatic agents include conductive polymers, metal oxides, surfactants, and carbon-based materials.

[0059] (conductive polymer) The conductive polymer is not particularly limited, but π-conjugated conductive polymers (i.e., conductive polymers whose main chain is composed of a π-conjugated system) are preferred. Examples of π-conjugated conductive polymers include polypyrrole-based conductive polymers, polythiophene-based conductive polymers, polyacetylene-based conductive polymers, polyphenylene-based conductive polymers, polyphenylene-vinylene-based conductive polymers, polyaniline-based conductive polymers, polyacene-based conductive polymers, polythiophene-vinylene-based conductive polymers, and copolymers thereof. These can be used individually or in combination of two or more.

[0060] Examples of polythiophene-based conductive polymers include polythiophene, poly(3-methylthiophene), poly(3-ethylthiophene), poly(3-propylthiophene), poly(3-butylthiophene), poly(3-hexylthiophene), poly(3-heptylthiophene), poly(3-octylthiophene), poly(3-decylthiophene), poly(3-dodecylthiophene), poly(3-octadecylthiophene), poly(3-bromothiophene), poly(3-chlorothiophene), and poly(3- Iodothiophene, poly(3-cyanothiophene), poly(3-phenylthiophene), poly(3,4-dimethylthiophene), poly(3,4-dibutylthiophene), poly(3-hydroxythiophene), poly(3-methoxythiophene), poly(3-ethoxythiophene), poly(3-butoxythiophene), poly(3-hexyloxythiophene), poly(3-heptyloxythiophene), poly(3-octyloxythiophene), poly(3-decyloxythiophene), poly(3-dodecylthiophene) Poly(3,4-Octadecyloxythiophene), Poly(3,4-Dihydroxythiophene), Poly(3,4-Dimethoxythiophene), Poly(3,4-Diethoxythiophene), Poly(3,4-Dipropoxythiophene), Poly(3,4-Dibutoxythiophene), Poly(3,4-Dihexyloxythiophene), Poly(3,4-Diheptyloxythiophene), Poly(3,4-Dioctyloxythiophene), Poly(3,4-Didecyloxythiophene), Poly(3,4- Examples include poly(3,4-ethylenedioxythiophene), poly(3,4-propylenedioxythiophene), poly(3,4-butylenedioxythiophene), poly(3-methyl-4-methoxythiophene), poly(3-methyl-4-ethoxythiophene), poly(3-carboxythiophene), poly(3-methyl-4-carboxythiophene), poly(3-methyl-4-carboxyethylthiophene), and poly(3-methyl-4-carboxybutylthiophene).

[0061] Examples of polypyrrole-based conductive polymers include polypyrrole, poly(N-methylpyrrole), poly(3-methylpyrrole), poly(3-ethylpyrrole), poly(3-n-propylpyrrole), poly(3-butylpyrrole), poly(3-octylpyrrole), poly(3-decylpyrrole), poly(3-dodecylpyrrole), poly(3,4-dimethylpyrrole), poly(3,4-dibutylpyrrole), poly(3-carboxypyrrole), poly(3-methyl-4-carboxypyrrole), poly(3-methyl-4-carboxyethylpyrrole), poly(3-methyl-4-carboxybutylpyrrole), poly(3-hydroxypyrrole), poly(3-methoxypyrrole), poly(3-ethoxypyrrole), poly(3-butoxypyrrole), poly(3-hexyloxypyrrole), and poly(3-methyl-4-hexyloxypyrrole).

[0062] Examples of polyaniline-based conductive polymers include polyaniline, poly(2-methylaniline), poly(3-isobutylaniline), poly(2-anilinesulfonic acid), and poly(3-anilinesulfonic acid).

[0063] Among the π-conjugated conductive polymers mentioned above, poly(3,4-ethylenedioxythiophene) is particularly preferred in terms of conductivity, transparency, and heat resistance.

[0064] From the viewpoint of improving conductivity, conductive polymers are preferably used in combination with dopants, and in particular, a composite of conductive polymer and dopant (conductive composite) is preferred. Polystyrene sulfonic acid (PSS) is preferred as a dopant for π-conjugated conductive polymers.

[0065] The weight-average molecular weight of polystyrene sulfonic acid is preferably between 20,000 and 1,000,000. The content ratio of polystyrene sulfonic acid in the conductive composite is preferably in the range of 1 to 10,000 parts by mass per 10 parts by mass of π-conjugated conductive polymer. The conductive composite may contain one type of polystyrene sulfonic acid or two or more types.

[0066] In a composite of a π-conjugated conductive polymer and polystyrene sulfonic acid, it is believed that at least some of the sulfonic acid groups of the polystyrene sulfonic acid are coordinated to the π-conjugated conductive polymer. The PEDOT / PSS combination is preferred as the conductive composite.

[0067] In the aqueous coating agent of the present invention, the content of the conductive polymer (e.g., conductive composite) is preferably 10 to 1000 parts by mass per 100 parts by mass of the acid-modified polyolefin resin (A).

[0068] (Metal oxides) Examples of metal oxides include tin oxide, antimond-doped tin oxide, tungsten oxide, molybdenum oxide, vanadium oxide, indium-doped tin oxide, tin-doped indium oxide, aluminum-doped tin oxide, tungsten-doped tin oxide, titanium oxide-cerium oxide-tin oxide complex, and titanium oxide-tin oxide complex; zinc oxide compounds such as aluminum-doped zinc oxide, antimond-doped zinc oxide, gallium-doped zinc oxide, and indium-doped zinc oxide; indium oxide compounds such as fluorine-doped indium oxide and cadmium-doped indium oxide; and titanium oxide compounds such as niobium-doped titanium oxide.

[0069] The shape of the metal oxide can be, for example, particulate. Its size is not particularly limited, but since transparency increases as the particle size decreases, the average particle size is preferably 200 nm or less, more preferably 50 nm or less, and even more preferably 20 nm or less.

[0070] Commercially available metal oxides can be used. Examples of such commercial products include "AS11T" (tin oxide ultrafine particle aqueous dispersion) manufactured by Unitika Ltd., "SN-100D" (antimond-doped tin oxide-based ultrafine particle aqueous dispersion) manufactured by Ishihara Sangyo Co., Ltd., "ITO" (tin oxide-doped indium ultrafine particles) manufactured by CI Kasei Co., Ltd., and "23-K" (aluminum-doped zinc oxide ultrafine particles) manufactured by Hakusui Tech Co., Ltd.

[0071] In the aqueous coating agent of the present invention, the metal oxide content is preferably 30 to 1500 parts by mass per 100 parts by mass of acid-modified polyolefin resin (A).

[0072] (Surfactants) Surfactants generally include those used in emulsion polymerization and emulsifiers. Examples of surfactants include cationic surfactants, anionic surfactants, nonionic surfactants, amphoteric surfactants, fluorinated surfactants, and reactive surfactants. These can be used individually or in combination of two or more.

[0073] Examples of anionic surfactants include sulfate ester salts of higher alcohols, higher alkyl sulfonic acids and their salts, alkylbenzene sulfonic acids and their salts, polyoxyethylene alkyl sulfate salts, polyoxyethylene alkylphenyl ether sulfate salts, and vinyl sulfosuccinates.

[0074] Examples of nonionic surfactants include compounds having a polyoxyethylene structure such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyethylene glycol fatty acid esters, ethylene oxide-propylene oxide copolymers (including random copolymers, block copolymers, and graft copolymers), and polyoxyethylene fatty acid amides, as well as sorbitan derivatives such as polyoxyethylene sorbitan fatty acid esters.

[0075] Examples of amphoteric surfactants include lauryl betaine and lauryl dimethylamine oxide.

[0076] Examples of reactive surfactants include compounds having reactive double bonds, such as allylalkylphenol polyethylene oxide adducts and their sulfate ester salts, and allyldialkylphenol polyethylene oxide adducts and their sulfate ester salts.

[0077] In the aqueous coating agent of the present invention, the surfactant content is preferably 0.01 to 20 parts by mass per 100 parts by mass of acid-modified polyolefin resin (A).

[0078] (Carbon-based materials) Examples of carbon-based materials include carbon nanotubes, fullerenes, graphene, carbon fibers, and carbon black. Among these, carbon nanotubes are preferred because they provide high conductivity.

[0079] Carbon nanotubes include single-walled carbon nanotubes and multi-walled carbon nanotubes. The average diameter of the carbon nanotubes is preferably 0.5 to 100 nm. The average length of the carbon nanotubes is preferably 0.1 to 1000 μm.

[0080] In the aqueous coating agent of the present invention, the carbon-based material content is preferably 10 to 200 parts by mass per 100 parts by mass of acid-modified polyolefin resin (A).

[0081] (Manufacturing of water-based coating agents) The aqueous coating agent of the present invention can be manufactured by uniformly mixing and dispersing an acid-modified polyolefin resin (A) and a long-chain alkyl-containing acrylic resin (B) in an aqueous medium.

[0082] The aqueous coating agent of the present invention can be prepared, for example, by mixing an aqueous dispersion of an acid-modified polyolefin resin (A) with an aqueous dispersion or aqueous solution of a long-chain alkyl-containing acrylic resin (B), and adding an aqueous medium as needed; or by mixing the acid-modified polyolefin resin (A) and the long-chain alkyl-containing acrylic resin (B), and then adding an aqueous medium and stirring and heating. While either of the above methods can easily prepare an aqueous coating agent with a desired component ratio, the former method is simpler and therefore preferred.

[0083] Commercially available products can be used as aqueous dispersions of acid-modified polyolefin resin (A). Examples of commercially available products include the Superclon series (E-723, E-503, etc.) and Zaixen series (Zaixen A, Zaixen L) from Nippon Paper Chemicals Co., Ltd., and the Chemipearl series (S-100, S-75N, etc.) from Mitsui Chemicals, Inc.

[0084] Commercially available products may be used as the aqueous dispersion or aqueous solution of the long-chain alkyl-containing acrylic resin (B). Examples of commercially available products include "ARUFON UF-5000 series" from Toagosei Co., Ltd., "Piroyl 1010," "Piroyl 1010S," and "Piroyl 406" from Lion Specialty Chemicals Co., Ltd., and "Rezem series" from Chukyo Oil & Fat Co., Ltd.

[0085] In an aqueous coating agent, it is preferable that at least a portion of the carboxyl groups or carboxylic acid anhydride groups contained in the acid-modified polyolefin resin (A) form a salt with a basic compound. When the carboxyl groups of the acid-modified polyolefin resin (A) form a salt with a basic compound and become anionic, the aggregation of the acid-modified polyolefin resin (A) is suppressed by electrostatic repulsion, and its dispersibility is improved.

[0086] As for the basic compound, from the viewpoint of improving the adhesion of the release layer to the substrate, ammonia or organic amine compounds that volatilize during the formation of the release layer are preferred, and organic amine compounds with a boiling point of 30 to 250°C (preferably 50 to 200°C) are particularly preferred.

[0087] Examples of organic amine compounds include triethylamine (TEA), N,N-dimethylethanolamine, aminoethanolamine, N-methyl-N,N-diethanolamine, isopropylamine, iminobispropylamine, ethylamine, diethylamine, 3-ethoxypropylamine, 3-diethylaminopropylamine, sec-butylamine, propylamine, methylaminopropylamine, 3-methoxypropylamine, monoethanolamine, morpholine, N-methylmorpholine, and N-ethylmorpholine.

[0088] The amount of basic compound added is preferably 0.3 to 3 equivalents, more preferably 0.5 to 2 equivalents, and particularly preferably 0.6 to 1.5 equivalents, relative to the carboxyl groups in the acid-modified polyolefin resin (A) (1 mole of carboxylic acid anhydride group is considered to be 2 moles of carboxyl groups).

[0089] The solid content concentration of the aqueous coating agent (for example, the total concentration of acid-modified polyolefin resin (A) and long-chain alkyl-containing acrylic resin (B)) is adjusted as appropriate depending on the film formation conditions, the desired thickness and performance of the coating film, etc., and is not particularly limited, but in order to maintain the viscosity of the aqueous coating agent appropriately and exhibit good coating film formation ability, 10 to 60% by mass is preferred, 15 to 50% by mass is more preferred, and 15 to 30% by mass is particularly preferred.

[0090] The aqueous coating agent contains an acid-modified polyolefin resin (A) and an acrylic resin having a long-chain alkyl group (B), wherein the content of the acrylic resin having a long-chain alkyl group (B) is 20 to 60 parts by mass, preferably 20 to 50 parts by mass, and more preferably 30 to 40 parts by mass, per 100 parts by mass of the acid-modified polyolefin resin (A).

[0091] In other words, the mass ratio (A / B) of the acid-modified polyolefin resin (A) to the long-chain alkyl-containing acrylic resin (B) in the aqueous coating agent is 100 / 20 to 100 / 60. By setting the ratio of the long-chain alkyl-containing acrylic resin (B) to 100 parts by mass of the acid-modified polyolefin resin (A) to 20 parts by mass or more, the release properties of the aqueous coating agent can be improved. Furthermore, by setting the ratio of the long-chain alkyl-containing acrylic resin (B) to 60 parts by mass or less, the adhesion to the substrate and transparency can be improved. The aforementioned mass ratio (A / B) is preferably 100 / 20 to 100 / 50, and more preferably 100 / 30 to 100 / 40.

[0092] The aqueous coating agent of the present invention may be subjected to treatments such as gamma ray irradiation, UV irradiation, or plasma irradiation as needed.

[0093] (Laminated structure) The laminate of the present invention has a configuration in which a coating film formed from the aqueous coating agent is laminated on a part or all of at least one surface of the base layer.

[0094] The laminate is a laminate comprising a coating film, wherein the coating film contains an acid-modified polyolefin resin (A) and an acrylic resin having a long-chain alkyl group (B), and the content of the acrylic resin having a long-chain alkyl group (B) is 20 to 60 parts by mass, preferably 20 to 50 parts by mass, and more preferably 30 to 40 parts by mass, per 100 parts by mass of the acid-modified polyolefin resin (A).

[0095] In other words, the mass ratio (A / B) of the acid-modified polyolefin resin (A) and the long-chain alkyl-containing acrylic resin (B) in the coating film is 100 / 20 to 100 / 60, preferably 100 / 20 to 100 / 50, and more preferably 100 / 30 to 100 / 40.

[0096] The aqueous coating agent exhibits good adhesion to various substrates. Therefore, by applying the aqueous coating agent and drying the coating film to remove the aqueous medium, a coating film with good adhesion to the substrate can be formed. The laminate of the coating film and substrate obtained in this way can be suitably used as a release film, release sheet, etc.

[0097] The substrate constituting the substrate layer is not particularly limited and can be, for example, paper, synthetic paper, thermoplastic resin films or molded products, glass, metal, aluminum foil or other metal foils (including metal foils that have been treated with rust prevention treatment, electrolyte resistance coating, etc.). Since the aqueous coating agent can form a coating film with excellent adhesion even with relatively low heat treatment, it can also be applied to substrates with relatively low heat resistance, such as thermoplastic resins with a melting point of 180°C or lower, such as polyethylene and polypropylene.

[0098] Among the aforementioned substrates, synthetic paper, thermoplastic resin film, and metal foil are preferred, thermoplastic resin film and metal foil are more preferred, and thermoplastic resin film is even more preferred.

[0099] Examples of thermoplastic resins constituting the aforementioned thermoplastic resin film include nylon 6, nylon 66, nylon 46, polyethylene terephthalate, polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate polyethylene succinate, polyglycolic acid, polylactic acid, polypropylene, polyethylene, polyurethane, polyimide resin, polycarbonate resin, polyarylate resin, ABS resin, acrylic resin, and mixtures thereof.

[0100] The thermoplastic resin film can be either an unstretched or stretched film, and the manufacturing method is not limited. While there are no particular limitations on the thickness of the thermoplastic resin film, it is typically in the range of 5 to 500 μm.

[0101] Thermoplastic resin films may contain fillers. Inorganic fillers are preferred, and examples include calcium carbonate, clay, silica, diatomaceous earth, talc, titanium dioxide, barium titanate, barium sulfate, and alumina.

[0102] The thermoplastic resin film may be subjected to various functional treatments such as barrier coatings, easy-adhesion coatings, antistatic coatings, and UV-shielding coatings, or various vapor deposition treatments such as silica, alumina, and aluminum. The aqueous coating agent also exhibits good adhesion to the treated surface.

[0103] The aqueous coating agent can be uniformly coated onto the substrate surface by known film formation methods, such as gravure roll coating, reverse roll coating, wire bar coating, lip coating, air knife coating, curtain flow coating, spray coating, dipping coating, or brush application, and if necessary, left to stand at room temperature before being subjected to drying or heat treatment for drying and baking, thereby forming a uniform coating film that adheres closely to the substrate surface.

[0104] For the aforementioned heat treatment, a conventional hot air circulation type oven or an infrared heater or other heating device can be used. By drying the coating film at a temperature of 50 to 200°C (preferably 100 to 180°C), sufficient adhesion to the substrate layer and release properties can be obtained. After drying, an aging treatment may be performed at 60 to 80°C to improve adhesion and promote the reaction.

[0105] The coating applied to the substrate can be subjected to stretching treatment. The stretching temperature is, for example, 70 to 120°C, and the stretching ratio is, for example, 2.5 to 7 times.

[0106] The thickness of the coating film on the laminate is not particularly limited, but from the viewpoint of improving release properties, it is preferably 0.1 μm or more, more preferably 0.2 μm or more, even more preferably 0.3 μm or more, and particularly preferably 0.5 μm or more. Furthermore, from the viewpoint of suppressing the decrease in workability due to prolonged drying time and suppressing the occurrence of cracks, the thickness of the coating film is preferably 20 μm or less, more preferably 15 μm or less, even more preferably 10 μm or less, and particularly preferably 5 μm or less.

[0107] The coating film on the laminate has good release properties to various adherends, and the peel strength of the adhesive tape obtained by the method described in the examples is, for example, 0.7 N / 25 mm or less, preferably 0.6 N / 25 mm or less, and more preferably 0.4 N / 25 mm or less.

[0108] The coating film on the laminate has excellent heat resistance, and the peel strength of the adhesive tape after heat treatment by the method described in the examples is, for example, 1.4 N / 25 mm or less, preferably 1.0 N / 25 mm or less, more preferably 0.8 N / 25 mm or less, even more preferably 0.5 N / 25 mm or less, and particularly preferably 0.3 N / 25 mm or less.

[0109] The laminate of the present invention can be used as a protective material for adhesive materials and liquid crystal display components (polarizing plates, phase difference polarizing plates, phase difference plates, etc.); a process material for prepregs used in the pressing process of printed circuit boards and structural materials for aircraft, etc.; and a release sheet for transfer printing, etc. The laminate of the present invention can be used particularly suitably as a protective material for adhesive materials.

[0110] Adhesive materials include adhesive tapes, adhesive sheets, adhesive tapes, and adhesive tapes. These materials generally consist of an adhesive formed in sheet form, and the adhesive layer may be laminated on a substrate made of paper, cloth, resin material, etc., or it may be substrate-less. Examples of adhesives included in the adhesive layer include acrylic adhesives, natural rubber adhesives, synthetic rubber adhesives, and silicone adhesives. The adhesive layer may also contain tackifiers such as rosin-based, coumarone-indene-based, terpene-based, petroleum-based, styrene-based, phenol-based, and xylene-based adhesives along with the adhesive.

[0111] Release films and release sheets are required to have release properties that allow them to be peeled off at the desired peel strength. For example, in the field of so-called "heavy peeling," it is preferable that the initial peel strength with acrylic adhesive materials and the peel strength after 24 hours at 70°C be 2.0 to 5.0 N / cm (5.0 to 12.5 N / 25 mm). In the field of so-called "light peeling" and "ultra-light peeling," it is required that the initial peel strength with acrylic adhesive materials and the peel strength after 24 hours at 70°C be 0.02 to 0.28 N / cm (0.05 to 0.7 N / 25 mm).

[0112] The laminate of the present invention, when a sample obtained by attaching the adhesive layer of a resin tape having an acrylic adhesive layer to the surface of the laminate is peeled off at 25°C under conditions of a peel angle of 180 degrees and a peel speed of 300 mm / min, exhibits a peel strength of, for example, 0.7 N / 25 mm or less, preferably 0.5 N / 25 mm or less, and more preferably 0.3 N / 25 mm or less.

[0113] It is preferable that the laminate of the present invention does not experience blocking when wound into a roll.

[0114] The laminate of the present invention is preferably highly transparent, and more preferably has a haze value of 10% or less, and more preferably 5% or less, in order to allow visual confirmation of the presence of air bubbles and foreign matter when used in bonding with an adherend.

[0115] Furthermore, the laminate of the present invention is often handled by being wound into a roll, but it is preferable that the components of the coating film do not migrate to the back surface of the substrate when wound into a roll. Such migration of coating film components to the back surface, that is, detachment of coating film components from the substrate, can be easily determined by applying an adhesive tape to the coating film surface, holding it under certain conditions, peeling off the adhesive tape, and measuring the remaining adhesion rate of the adhesive tape. In other words, the less the adhesiveness of the adhesive tape decreases, the less the coating film has detached and / or the adhesive tape could be peeled off smoothly without roughening the surface of the adhesive tape. The degree of decrease in the adhesiveness of the adhesive tape can be determined from the adhesion when it is reapplied. Furthermore, if the same evaluation is performed in a high-temperature environment and it is determined that it has sufficient adhesion, it can be said that the laminate has excellent heat resistance.

[0116] The residual adhesion rate of the laminate of the present invention, obtained by the method described in the examples, is, for example, 80% or more, preferably 90% or more.

[0117] The laminate of the present invention can be suitably used, for example, as a release film or a release sheet.

[0118] When the laminate of the present invention is used as a release sheet for transfer printing, various functional layers such as a printing layer, electrodes, and a protective layer are formed on the coating film by coating or the like. The functional layers formed on the coating film are then heat-pressed onto the object to be transferred, and the coating film is then peeled off from the functional layers to transfer the functional layers to the object to be transferred. In this way, the laminate of the present invention can be used for foil stamping, also known as stamping foil. The functional layers can be provided using, for example, metallic foil, pigment foil, multicolor printing foil, hologram foil, electrostatic discharge foil, half-mirror metallic foil, etc.

[0119] The laminate of the present invention exhibits excellent release properties and release properties after heat treatment, making it suitable for a wide range of applications including automobile manufacturing, electronic equipment manufacturing, medical equipment, and food packaging. It is particularly suitable for use on substrates and components of electronic equipment, printed circuit board surfaces, and display substrates. In addition to release applications, it can be used in a wide range of other applications, such as delate tack layers and heat seal layers for food and industrial packaging, as a coating for corrugated cardboard surfaces and films to create smooth and sealing layers, as an ink binder, as a primer for hard coat layers, as wallpaper for building materials, and as a water-repellent coating for concrete.

[0120] The configurations and combinations thereof described above are merely examples, and additions, omissions, substitutions, and modifications to the configurations are permitted as appropriate, without departing from the spirit of the present invention. Furthermore, the present invention is not limited by its embodiments. [Examples]

[0121] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Various characteristics were measured or evaluated by the following methods.

[0122] 1. Acid-modified polyolefin resin (1) Composition 1 The results were determined by 1H-NMR analysis (Varian, 300 MHz). Measurements were taken at 120°C using orthodichlorobenzene (d4) as the solvent.

[0123] 2. Aqueous dispersion of acid-modified polyolefin resin (1) Solid content concentration of aqueous dispersion An appropriate amount of aqueous dispersion was weighed, heated at 150°C until the mass of the residual material (solids) reached a constant weight, and the solids concentration was determined. (2) Average particle size of aqueous dispersion The number-average particle size (mn), weight-average particle size (mw), and volume-average particle size (mv) were determined using a Nikkiso Co., Ltd. Microtrac particle size analyzer UPA150 (MODEL No. 9340, dynamic light scattering method). The refractive index of the resin used for particle size calculation was set to 1.50.

[0124] 3. Characteristics of water-based coating agents (1) Storage stability The aqueous coating agent was left at 25°C for 6 months, and its appearance was visually observed over time to evaluate its storage stability according to the following criteria. <Evaluation Criteria> Good ○: No change Acceptable (△): It was usable after 1 hour of preparation, but solidification, gelation, or aggregation occurred after 2 hours. Unacceptable ×: Solidification, gelation, or aggregation occurred 30 minutes after preparation.

[0125] 4. Characteristics of coatings and laminates In the following evaluations, a biaxially oriented polyethylene terephthalate film (Emblet S-50, manufactured by Unitika Ltd., 50 μm thick, hereinafter referred to as "PET film") was used as the thermoplastic resin film base.

[0126] (1) Adhesion to substrate (tape peel test) An aqueous coating agent was applied to the corona-treated surface of a PET film using a Meyer bur so that the film thickness after drying would be 3 μm. The mixture was then dried at 60°C for 30 seconds to obtain a laminate of the aqueous coating agent and the PET film. Immediately after obtaining the laminate, TESA tape (TESA7475, manufactured by Tesa Tape Co., Ltd.) was applied to the coated surface, and then the tape was peeled off in one swift motion. The degree of peeling of the coated surface was then visually observed, and the adhesion to the substrate was evaluated according to the following criteria. <Evaluation Criteria> Good: No peeling at all. OK △: Partial peeling Not possible ×: Completely peel off

[0127] (2) Transparency (haze value) A PET film with a haze value of 1.0% was coated with an aqueous coating agent using a Meyer bur to achieve a film thickness of 2 μm after drying. The coating was then dried at 100°C for 30 seconds to prepare test specimens. The overall haze value (%) of the obtained test specimens was measured using a turbidimeter NDH2000 manufactured by Nippon Denshoku Industries Ltd. in accordance with JIS K7105, and the transparency was evaluated according to the following criteria. <Evaluation Criteria> Good (○): 1-5% Possible△: More than 5%, less than 10% Not possible ×: More than 10%

[0128] (3) Blocking resistance A aqueous coating agent was applied to a PET film using a Meyer burr to achieve a dry film thickness of 5 μm. The film was then dried at 100°C for 30 seconds to obtain a laminate of the aqueous coating agent and the PET film. When K-2 was used as the crosslinking agent, the film was dried at 150°C for 30 seconds. A PET film was overlaid on the coated surface of the resulting laminate, and a load of 0.1 MPa was applied. The laminate was then left for 24 hours at 30°C and 65% RH. Subsequently, the resistance to blocking was evaluated based on the peelability of the overlaid PET film according to the following criteria. <Evaluation Criteria> Good: The PET film peeled off with just a light lift. OK △: The PET film peeled off when pulled. Unacceptable ×: The PET film is torn, or the coating has delaminated at the interface or has agglomerated.

[0129] (4) Mold releasability A aqueous coating agent was applied to a PET film using a Meyer burr to achieve a dry film thickness of 0.5 μm. The film was then dried at 100°C for 30 seconds to obtain a laminate of the aqueous coating agent and the PET film. When K-2 was used as the crosslinking agent, the film was dried at 150°C for 30 seconds. After applying adhesive tape (Nitto Denko Corporation No. 31B / acrylic adhesive) to the coated surface of the resulting laminate, it was cut into 25mm wide strips to obtain samples. The obtained samples were tested using a tensile testing machine (Intesco Co., Ltd. Precision Universal Material Testing Machine Model 2020) in a constant temperature chamber at 25°C. The adhesive tape was peeled from the coating surface at a tensile speed of 300 mm / min and a peeling angle of 180 degrees. The peel strength required for this peeling was measured, and the release properties of the coating surface were evaluated according to the following criteria. <Evaluation Criteria> Good ○: Peel strength is 0.7N / 25mm or less Not acceptable ×: Peel strength exceeding 0.7N / 25mm

[0130] (5) Release properties after heat treatment (4) Samples were prepared in the same manner as for mold release, and the obtained samples were subjected to heat treatment at 70°C for 24 hours. Then, the peel strength of the heat-treated samples was measured in the same manner as for mold release, and the mold release properties of the coated surface after heat treatment were evaluated according to the following criteria. <Evaluation Criteria> Good ○: Peel strength is 1.4N / 25mm or less Not acceptable ×: Peel strength exceeding 1.4N / 25mm

[0131] (6)Residual adhesion rate (4) In the release strength test, an adhesive tape (25 mm wide, 150 mm long) peeled off the coated surface was attached to the corona-treated surface of the PET film, a load of 2 kPa was applied, and it was left at 25°C for 20 hours. After that, the peel strength (F1) between the adhesive tape and the PET film was measured in the same manner as in (4) release strength. On the other hand, an unused adhesive tape (No. 31B, manufactured by Nitto Denko Corporation) measuring 50 mm in width and 150 mm in length was attached to the corona-treated surface of the PET film, a load of 2 kPa was applied, and it was left at 25°C for 20 hours. After that, the peel strength (F2) between the adhesive tape and the PET film was measured using the same method as in (4) release properties, and the residual adhesion rate was calculated from the following formula and evaluated according to the following criteria. Residual adhesion rate (%)=(F1 / F2)×100 <Evaluation Criteria> Good (○): Residual adhesion rate of 80% or more Unacceptable ×: Residual adhesion rate is less than 80%

[0132] (7) Chemical resistance A water-based coating agent was applied to a PET film using a Meyer burr to achieve a dry film thickness of 2 μm. The film was then dried at 100°C for 30 seconds to form a coating. The resulting coating was rubbed five times with cotton wool soaked in toluene, and the chemical resistance of the coating surface was evaluated by visual inspection according to the following criteria. <Evaluation Criteria> Good ○: No change Acceptable △: Slight whitening present Unacceptable ×: Whitening or paint peeling present.

[0133] Preparation Example 1 (Preparation of an aqueous dispersion of acid-modified polyolefin resin (E-1)) A stirrer equipped with a sealed, pressure-resistant 1L glass container with a heater was used. 60.0g of acid-modified polyolefin resin (A1) (Arkema Bondine HX-8290), 60.0g of IPA, 2.2g of TEA, and 177.8g of distilled water were placed in the glass container of the stirrer, and the mixture was stirred at a rotation speed of 300 rpm. As a result, no sedimentation of resin granules was observed at the bottom of the container, and it was confirmed that the resin was suspended. Stirring was then continued for another 10 minutes, after which the heater was turned on to raise the system temperature to 120°C, and stirring was continued at that temperature for another 20 minutes. After that, the mixture was cooled to 25°C by air cooling while stirring at a rotation speed of 300 rpm, and pressure filtration (air pressure 0.2 MPa) was performed using a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a milky white, uniform aqueous dispersion (E-1) of acid-modified polyolefin resin (A1).

[0134] Preparation Example 2 (Preparation of an aqueous dispersion of acid-modified polyolefin resin (E-2)) A stirrer equipped with a sealed, pressure-resistant 1L glass container with a heater was used. 100.0g of acid-modified polyolefin resin (A2) (Arkema Bondine TX-8030), 150.0g of IPA, 6.0g of TEA, and 244.0g of distilled water were placed in the glass container of the stirrer, and the mixture was stirred at a rotation speed of 300 rpm. As a result, no sedimentation of resin granules was observed at the bottom of the container, and it was confirmed that the resin was suspended. Stirring was then continued for another 10 minutes, after which the heater was turned on to raise the system temperature to 130°C, and stirring was continued at that temperature for another 30 minutes. After that, the mixture was cooled to 25°C by air cooling while stirring at a rotation speed of 300 rpm, and pressure filtration (air pressure 0.2 MPa) was performed using a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a milky white, uniform aqueous dispersion (E-2) of acid-modified polyolefin resin (A2).

[0135] Preparation Example 3 (Preparation of an aqueous dispersion of acid-modified polyolefin resin (E-3)) An aqueous dispersion of acid-modified polyolefin resin (A3) (E-3) was obtained in the same manner as in Preparation Example 2, except that acid-modified polyolefin resin (A3) (Bondine LX-4110, manufactured by Arkema) was used instead of acid-modified polyolefin resin (A2).

[0136] Preparation Example 4 (Preparation of an aqueous dispersion of acid-modified polyolefin resin (E-4)) A stirrer equipped with a sealed, pressure-resistant 1L glass container with a heater was used. 60.0g of acid-modified polyolefin resin (A4) (Dow Chemical's Primacol 5980I), 16.8g of TEA, and 223.2g of distilled water were placed in the glass container of the stirrer, and the mixture was stirred at a rotation speed of 300 rpm. As a result, no sedimentation of resin granules was observed at the bottom of the container, and it was confirmed that the resin was suspended. Stirring was then continued for another 10 minutes, after which the heater was turned on to raise the system temperature to 130°C, and stirring was continued at that temperature for another 30 minutes. After that, the mixture was cooled to 25°C by air cooling while stirring at a rotation speed of 300 rpm, and pressure filtration (air pressure 0.2 MPa) was performed using a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a slightly white aqueous dispersion (E-4) of acid-modified polyolefin resin (A4).

[0137] Preparation Example 5 (Preparation of an aqueous dispersion of acid-modified polyolefin resin (E-5)) 280 g of propylene-butene copolymer (propylene / butene = 80 / 20 mass%) was placed in a four-necked flask and heated to melt under a nitrogen atmosphere. The system temperature was then maintained at 170°C and stirred. 25.0 g of maleic anhydride as an unsaturated carboxylic acid and 6.0 g of dicumyl peroxide as a radical generator were added over 1 hour each, and the mixture was reacted for another hour. After the reaction was complete, the resulting reaction product was placed in a large amount of acetone to precipitate the resin. This resin was washed several times with acetone to remove unreacted maleic anhydride, and then dried under reduced pressure in a vacuum dryer. This yielded an acid-modified polyolefin resin (A5).

[0138] A stirrer equipped with a sealed, pressure-resistant 1L glass container with a heater was used. 60.0g of the obtained acid-modified polyolefin resin (A5), 45.0g of ethylene glycol-n-butyl ether, 8.0g of N,N-dimethylethanolamine, and 137.0g of distilled water were charged into the glass container of the stirrer, and the mixture was stirred at a rotation speed of 300 rpm. As a result, no sedimentation of resin granules was observed at the bottom of the container, and it was confirmed that the resin was suspended. Therefore, stirring was continued for another 10 minutes, and then the heater was turned on to raise the system temperature to 160°C, and the mixture was stirred at that temperature for another 60 minutes. After that, the mixture was cooled by air cooling until the internal temperature reached 80°C, then opened, and 45.0g of tetrahydrofuran, 5.0g of N,N-dimethylethanolamine, and 30.0g of distilled water were added, the container was sealed, and the mixture was stirred for another 60 minutes while maintaining the system temperature at 140°C with a rotation speed of 300 rpm. Subsequently, the mixture was cooled to 25°C by air cooling while being stirred at a rotation speed of 300 rpm, and then pressure filtered (air pressure 0.2 MPa) through a 300-mesh stainless steel filter (wire diameter 0.035 mm, plain weave) to obtain a slightly turbid aqueous dispersion (E-5) of acid-modified polyolefin resin (A5). At this point, almost no resin remained on the filter.

[0139] The composition and physical properties of the aqueous dispersion of acid-modified polyolefin resin obtained in the preparation example are shown in Table 1 below.

[0140] [Table 1]

[0141] The following materials were used as raw materials for the water-based coating agent. a. Aqueous dispersion of acid-modified polyolefin resin E-1 to E-5: Aqueous dispersions obtained in Preparation Examples 1 to 5 were used.

[0142] b. Long-chain alkyl group-containing acrylic resin G-1: Aqueous dispersion of acrylic resin having long-chain alkyl pendants, volume average particle size: 710 nm, manufactured by Lion Specialty Chemicals Co., Ltd., P-Royl 406, solvent: water, solids concentration: 15% by mass G-2: Aqueous dispersion of acrylic resin having long-chain alkyl groups, volume average particle size: 310 nm, manufactured by Chukyo Oil & Fat Co., Ltd., Rezem CA-192, solvent: water, solids concentration: 20% by mass G-3: Aqueous solution of carboxylic acid-type acrylic resin having a long-chain alkyl group, ARUFON UF-5080 manufactured by Toagosei Co., Ltd., adjusted to a solid content concentration of 20% by mass with a 5% sodium hydroxide aqueous solution.

[0143] c Long-chain alkyl compounds G-4: Aqueous dispersion of a compound in which long-chain alkyl groups are added to the side chains and / or terminals of a resin other than acrylic resin, manufactured by Chukyo Oil & Fat Co., Ltd., Rezem K-256, solid content concentration: 20% by mass

[0144] d Crosslinking agent K-1: Epocross WS-700 manufactured by Nippon Shokubai Co., Ltd. (Aqueous solution of oxazoline compound containing 2-isopropenyl-2-oxazoline, solid content concentration 25% by mass) K-2: Denacol EX-313 manufactured by Nagase ChemteX Corporation (epoxy crosslinking agent, used without dilution) K-3: BASONAT HW1000 manufactured by BASF (isocyanate-based crosslinking agent, to be used undiluted) K-4: Orgatics TC-400 manufactured by Matsumoto Fine Chemical Co., Ltd. (titanium-based crosslinking agent, 2-propanol solution, component concentration 79% by mass)

[0145] Example 1 An aqueous dispersion (E-1) and an acrylic resin having a long-chain alkyl group (G-1) were mixed so that the solid content mass ratio was 100 / 40, and the mixture was stirred at room temperature for 5 minutes to obtain an aqueous coating agent.

[0146] Examples 2-18, Comparative Examples 1-5 An aqueous coating agent was obtained in the same manner as in Example 1, except that the formulation was modified as shown in Tables 2 and 3 below.

[0147] The properties of the aqueous coating agents obtained in the examples and comparative examples were evaluated. The results are shown in Tables 2 to 4 below.

[0148] [Table 2]

[0149] [Table 3]

[0150] [Table 4]

[0151] From the examples, it can be seen that the aqueous coating agent of the present invention contains an acid-modified polyolefin resin (A) and a long-chain alkyl-containing acrylic resin (B) in specific proportions, and therefore exhibits excellent release properties and release properties after heat treatment. Furthermore, it can be seen that adding a crosslinking agent to the aqueous coating agent of the present invention significantly improves the excellent chemical resistance of the coating film.

[0152] Comparative Example 1 shows that when the aqueous coating agent does not contain a long-chain alkyl-containing acrylic resin (B), the resulting coating film has poor release properties and blocking resistance after heat treatment. Comparative Example 2 shows that when the content of long-chain alkyl-containing acrylic resin (B) in the aqueous coating agent is insufficient, the release properties, release properties after heat treatment, and anti-blocking properties are inferior. Comparative Example 3 shows that when the content of long-chain alkyl-containing acrylic resin (B) in the aqueous coating agent is excessive, the release properties, release properties after heat treatment, haze, and chemical resistance are inferior. Comparative Example 4 shows that when the aqueous coating agent contains a long-chain alkyl compound whose main chain is a resin other than an acrylic resin, instead of the long-chain alkyl-containing acrylic resin (B) whose main chain is an acrylic resin, the resulting coating film has poor release properties after heat treatment. Comparative Example 5 shows that when the aqueous coating agent does not contain acid-modified polyolefin resin (A), the resulting coating film has inferior substrate adhesion, residual adhesion rate, and chemical resistance. [Industrial applicability]

[0153] The coating film obtained from the aqueous coating agent of the present invention exhibits excellent adhesion to the substrate, release properties of the adherend, and release properties after heat treatment. Therefore, it can be suitably used as a material for forming release layers such as release films and release sheets used in processes that include heat treatment.

Claims

1. It contains an acid-modified polyolefin resin (A), an acrylic resin having a long-chain alkyl group (B), and an aqueous medium (C). An aqueous coating agent comprising 20 to 60 parts by mass of an acrylic resin (B) having a long-chain alkyl group, relative to 100 parts by mass of an acid-modified polyolefin resin (A).

2. A laminate comprising a coating film on part or all of at least one surface of a base layer, A laminate in which the coating film contains an acid-modified polyolefin resin (A) and an acrylic resin (B) having a long-chain alkyl group, wherein the content of the acrylic resin (B) having a long-chain alkyl group is 20 to 60 parts by mass per 100 parts by mass of the acid-modified polyolefin resin (A).

3. The laminate according to claim 2, wherein the base layer is a thermoplastic resin film or a metal foil.

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