Water-based release coating and laminate

Abstract

The present invention provides an aqueous release coating agent and a laminate using the same, which exhibits excellent adhesion to various substrates when used as a release layer, excellent release properties, excellent release properties after heat treatment, and also excellent slipperiness and transparency. [Solution] An aqueous release coating agent containing an acid-modified polyolefin resin (A), an organotitanium compound (B), and an aqueous medium, wherein the mass ratio of the acid-modified polyolefin resin (A) to titanium is 100 / 0.5 to 100 / 20. Preferably, the chelate-type organotitanium compound is titanium diisopropoxybis(triethanolamine) or titanium diethanolamine. A laminate is obtained by laminating a release layer obtained by removing the aqueous medium from the aqueous release coating agent.

Description

Technical Field

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

Background Art

[0002] Adhesive sheets are used in various applications, including the manufacturing processes of electronic components such as semiconductor devices and precision instruments. In order to protect the surface of such adhesive sheets, a release sheet is laminated thereon until use.

[0003] On the surface of the base material constituting the release sheet, a resin layer having releasability is provided to facilitate peeling from the adhesive sheet. In such a resin layer, silicone-based release agents are often used as release agents. When a silicone-based release agent is used, low-molecular-weight silicone compounds contained in the silicone-based release agent may migrate to the adhesive surface of the adhesive sheet and contaminate the adhesive sheet surface. Therefore, studies on non-silicone-based release agents have been underway.

[0004] Patent Document 1 describes a release layer made of a combination of an acid-modified polyolefin and an oxazoline compound as a non-silicone-based release coating agent.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] With the increasing complexity of electronic component manufacturing processes, steps such as forming a layer on the opposite side of a non-silicone release agent layer with adhesive tape, pressing to bond with resin, and infrared / UV irradiation to peel the silicone wafer from the release layer are performed. During these processes, the release layer is subjected to heat, requiring it to maintain a peel strength similar to its initial release strength even after undergoing such a heated environment (post-heat treatment release properties). Post-heat treatment release properties are particularly important for release sheets that have a release layer on both sides. Each release layer formed on both sides is set to have a different peel strength to control which layer is peeled off during the manufacturing process. If the peel strength changes due to heat treatment or over time, it not only becomes impossible to control the peeling as intended, but unintended peeling from the wrong layer can lead to machine failure. For these reasons, the release properties of non-silicone mold release coatings (Patent Document 1) after heat treatment were not always satisfactory.

[0007] The object of the present invention is to provide an aqueous release coating agent that exhibits excellent adhesion to various substrates when used as a release layer, release properties in a temperature environment close to room temperature (5-40°C), and excellent release properties after heat treatment at temperatures exceeding the aforementioned temperature, as well as a laminate using the same. [Means for solving the problem]

[0008] As a result of diligent research, the inventors of the present invention discovered that an aqueous release coating agent obtained by mixing a specific amount of an organotitanium compound with an acid-modified polyolefin resin can solve the above problems, and thus arrived at the present invention.

[0009] In other words, the gist of this invention is as follows: (1) An aqueous release coating agent containing an acid-modified polyolefin resin (A), an organotitanium compound (B), and an aqueous medium, wherein the mass ratio of the acid-modified polyolefin resin (A) to titanium is 100 / 0.5 to 100 / 20. (2) The aqueous release coating agent according to (1), wherein the organotitanium compound (B) is a chelate-type organotitanium compound. (3) The aqueous release coating agent according to (2), wherein the chelate-type organotitanium compound is titanium diisopropoxybis(triethanolamine) or titanium diethanolamine. (4) A release layer obtained by removing the aqueous medium from any of the aqueous release coating agents from (1) to (3). (5) A laminate comprising a release layer as described in (4) laminated on at least a portion of at least one side of a substrate. (6) The laminate according to (5), wherein the base material is a thermoplastic resin film or a metal foil. [Effects of the Invention]

[0010] The release layer obtained from the aqueous release coating agent of the present invention exhibits excellent adhesion to the substrate, release properties, and release properties after heat treatment. [Modes for carrying out the invention]

[0011] The present invention will be described in detail below. The aqueous release coating agent of the present invention contains an acid-modified polyolefin resin (A) and an organotitanium compound (B).

[0012] (Acid-modified polyolefin resin (A)) The acid-modified polyolefin resin (A) in the present invention is obtained by acid-modifying a polyolefin resin with an unsaturated carboxylic acid component.

[0013] The amount of unsaturated carboxylic acid component in the acid-modified polyolefin resin (A) is preferably 0.1 to 25% by mass, more preferably 0.5 to 15% by mass, even more preferably 1 to 8% by mass, and particularly preferably 1 to 5% by mass, from the viewpoint of adhesion between the resulting release layer and the substrate.

[0014] Unsaturated carboxylic acid components are introduced into polyolefin resins in the form of unsaturated carboxylic acids or their anhydrides. Specific examples of unsaturated carboxylic acids and their anhydrides include acrylic acid, methacrylic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, crotonic acid, as well as half-esters and half-amides of unsaturated dicarboxylic acids. Among these, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are preferred, with acrylic acid and maleic anhydride being more preferred.

[0015] The unsaturated carboxylic acid component only needs to be copolymerized in the polyolefin resin, and its form is not limited; for example, random copolymerization, radical copolymerization, block copolymerization, graft copolymerization, etc.

[0016] Examples of olefin components constituting polyolefin resins include alkenes such as ethylene, propylene, isobutylene, 1-butene, 1-pentene, 1-hexene, and 1-octene, as well as cycloalkenes such as norbornene. Mixtures of these can also be used. Among these, alkenes with 2 to 6 carbon atoms, such as ethylene, propylene, isobutylene, 1-butene, 1-pentene, and 1-hexene, are preferred, alkenes with 2 to 4 carbon atoms, such as ethylene, propylene, isobutylene, and 1-butene, are more preferred, and ethylene and propylene are particularly preferred.

[0017] The olefin component content in the acid-modified polyolefin resin (A) is preferably 50% by mass or more, and more preferably 70% by mass or more. If the olefin component content is less than 50% by mass, properties derived from the polyolefin resin, such as substrate adhesion, may be lost.

[0018] Acid-modified polyolefin resin (A) preferably contains a (meth)acrylic acid ester component to improve adhesion to thermoplastic resin substrates. The content of the (meth)acrylic acid ester component in the acid-modified polyolefin resin (A) is preferably 0.5 to 40% by mass, more preferably 1 to 35% by mass, even more preferably 3 to 30% by mass, particularly preferably 5 to 25% by mass, and most preferably 10 to 25% by mass in order to have good adhesion with various thermoplastic resin film substrates.

[0019] If the content of the (meth)acrylic acid ester component is less than 1% by mass, the adhesion to the thermoplastic resin film substrate may not be sufficient. If it exceeds 40% by mass, the properties of the olefin-derived resin may be lost, and the adhesion to the substrate may decrease.

[0020] Examples of the (meth)acrylic acid ester component include esterified products of (meth)acrylic acid and alcohols having 1 to 30 carbon atoms. Among them, esterified products of (meth)acrylic acid and alcohols having 1 to 20 carbon atoms are preferred from the viewpoint of easy availability. Specific examples of such compounds 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, etc. Mixtures of these may also be used. Among these, from the viewpoint of adhesion to the substrate film, methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, hexyl acrylate, octyl acrylate are more preferred, ethyl acrylate and butyl acrylate are more preferred, and ethyl acrylate is particularly preferred. Note that “(meth)acrylic acid ~” means “acrylic acid ~ or methacrylic acid ~”.

[0021] In addition to the above components, other components may be contained in an amount of about 10% by mass or less of the acid-modified polyolefin resin (A). Examples of the other components 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, and vinyl alcohol obtained by saponifying vinyl esters with a basic compound or the like, 2-hydroxyethyl acrylate, glycidyl (meth)acrylate, (meth)acrylonitrile, styrene, substituted styrene, carbon monoxide, sulfur dioxide, etc. Mixtures of these can also be used.

[0022] Examples of the acid-modified polyolefin resin (A) include ethylene-(meth)acrylic acid copolymer resins, ethylene-(meth)acrylate-maleic anhydride copolymer resins, ethylene-maleic anhydride copolymer resins, ethylene-propylene-butene-maleic anhydride copolymer resins, propylene-maleic anhydride copolymer resins, propylene-butene-maleic anhydride copolymer resins, α-olefin-ethylene-maleic anhydride copolymer resins, α-olefin-ethylene-(meth)acrylic acid copolymer resins, etc. The polyolefin resin may be chlorinated in the range of 5 to 40% by mass. Also, two or more of these listed acid-modified polyolefin resins may be mixed and used.

[0023] When the acid-modified polyolefin resin (A) contains an ethylene unit (A2) and a (meth)acrylate unit (A3), it is preferable that the total content of both in the acid-modified polyolefin resin (A) is 99 to 85% by mass, and more preferably 98 to 95% by mass.

[0024] When the acid-modified polyolefin resin (A) contains ethylene units (A2) and (meth)acrylic acid ester units (A3), the mass ratio (A2) / (A3) of the ethylene units (A2) to (meth)acrylic acid ester units (A3) in the acid-modified polyolefin resin (A) is preferably 55 / 45 to 96 / 4, and more preferably (80) / (20) to 95 / (5).

[0025] The melt flow rate of the acid-modified polyolefin resin (A) is not particularly limited, but from the viewpoint of release properties and adhesion to the substrate, a melt flow rate of 0.01 to 9000 g / 10 min at 190°C and a 2160 g load, 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 can be used. Aqueous release coatings with a melt flow rate of less than 0.01 g / 10 min for the acid-modified polyolefin resin (A) may have reduced adhesion to the substrate.

[0026] 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.

[0027] 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.

[0028] A commercially available product may 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, and A-5515, A-5260, and A-5320H from Mitsui Chemicals' Lucant series.

[0029] (Organotitanium compound (B)) Next, we will explain organotitanium compounds (B).

[0030] Examples of organotitanium compounds include titanium alkoxide compounds such as tetran-butyl titanate, tetrastearyl titanate, tetrater-butyl titanate, tetraisopropyl titanate, tetraoctyl titanate, and butyl titanate dimer; titanium octylene glycolate, titanium lactate, titanium diethanolamine, titanium triethanolamine, titanium aminoethylaminoethanolate, titanium tetraacetylacetonate, titanium acetylacetonate, titanium ethylacetoacetate, titanium dodecylbenzenesulfonate compounds, titanium phosphate ester complexes, chelate-type organotitanium compounds such as titanium lactate ammonium salts; and titanium acylate compounds such as titanium isostearate. Two or more of these may be included. Among these, chelated organotitanium compounds are preferred. Of the chelated organotitanium compounds, titanium triethanolamine and titanium diethanolamine are preferred.

[0031] Commercially available organic titanium compounds may be used. Examples of commercially available products include Matsumoto Fine Chemical's "Orgatics TA series" and "Orgatics TC series."

[0032] In the aqueous release coating agent of the present invention, the mixing ratio of the acid-modified polyolefin resin (A) and the organotitanium compound (B) must be such that the mass ratio of the acid-modified polyolefin resin (A) to the titanium contained in the organotitanium compound (B) is 100 / 0.5 to 100 / 20, preferably 100 / 1 to 100 / 10, and more preferably 100 / 1.5 to 100 / 5. If the proportion of titanium contained in the organotitanium compound (B) is less than 0.5% by mass relative to the acid-modified polyolefin resin (A), the aqueous release coating agent will have poor release properties and release properties after heat treatment, and if it exceeds 20% by mass, the liquid stability will be poor.

[0033] (Manufacturing of water-based release coating agents) Next, a method for producing the aqueous release coating agent of the present invention will be described. The method for producing the aqueous release coating agent of the present invention is not limited to a method in which an acid-modified polyolefin resin (A) and an organotitanium compound (B) are uniformly mixed and dispersed in an aqueous medium.

[0034] For example, one method involves mixing an aqueous dispersion of an acid-modified polyolefin resin (A) with a solvent solution of an organotitanium compound (B), and further adding water or a hydrophilic solvent as needed. Another method involves mixing the acid-modified polyolefin resin (A) and the organotitanium compound (B), and then stirring and heating them together with water or a solvent to obtain an aqueous dispersion. While any of the above methods can easily prepare an aqueous release coating agent with a desired component ratio, the former method is simpler and therefore preferred.

[0035] (aqueous medium) The aqueous medium is a medium whose main component is water, and may contain water-soluble organic solvents (alcohols, amines) to improve the dispersibility during the aqueous conversion of the acid-modified polyolefin resin. As for the organic solvent, from the viewpoint of obtaining a good aqueous dispersion, it is preferable that it has a solubility in water at 20°C of 20 g / liter or more, and more preferably 100 g / liter or more. The amount of organic solvent added 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, per 100 parts by mass of the aqueous dispersion of the polyolefin resin.

[0036] By heating the aqueous dispersion while stirring under atmospheric or reduced pressure, a portion of the organic solvent can be removed from the system (stripping), and ultimately the amount of organic solvent can be reduced to 1 part by mass or less per 100 parts by mass of the aqueous dispersion of polyolefin resin.

[0037] Specific examples of organic solvents used include methanol, ethanol, n-propanol, isopropanol, n-butanol, methyl ethyl ketone, cyclohexanone, tetrahydrofuran, dioxane, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, and ethylene glycol monobutyl ether. Among these, ethanol, isopropanol, and n-propanol are particularly preferred from the viewpoint of low-temperature drying properties.

[0038] In the aqueous release coating agent of the present invention, it is preferable that a portion of the carboxyl groups in the acid-modified polyolefin resin (A) are neutralized by a basic compound. The acid-modified polyolefin resin (A) has its carboxyl groups or acid anhydride groups anionized by the basic compound, and the electrostatic repulsion of the anions prevents aggregation between resin fine particles in the aqueous medium, thereby achieving good dispersion.

[0039] The amount of basic compound added is preferably 0.3 to 3 times the equivalent amount of carboxyl groups in the acid-modified polyolefin resin (A) (1 mole of acid anhydride group is considered to be 2 moles of carboxyl groups), more preferably 0.5 to 2 times the equivalent amount, and particularly preferably 0.6 to 1.5 times the equivalent amount.

[0040] As for the basic compound, ammonia or organic amine compounds that volatilize during the formation of the release layer are preferred from the viewpoint of the release layer's adhesion to the substrate, and among these, organic amine compounds with a boiling point of 30 to 250°C, and more preferably 50 to 200°C, are preferred.

[0041] Specific examples of organic amine compounds include triethylamine, 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.

[0042] Commercially available water-based polyolefin resins can be used as components of the water-based mold release coating agent, including the Superclon series (E-723, E-503, etc.) from Nippon Paper Chemicals, the Zaixen series (Zaixen A, Zaixen L) from Sumitomo Seika, and the Chemipearl series (S-100, S-75N, etc.) from Mitsui Chemicals.

[0043] For the aqueous polyolefin resin aqueous dispersion constituting the aqueous release coating agent, the number-average particle size (mn) is preferably 5 to 500 nm, more preferably 7 to 300 nm, and particularly preferably 10 to 200 nm, in order to maintain good viscosity as an aqueous dispersion and for surface smoothness of the coating film. The weight-average particle size (mw) is preferably 5 to 800 nm, more preferably 10 to 500 nm, and particularly preferably 30 to 300 nm.

[0044] The content of acid-modified polyolefin resin (A) in the aqueous release coating agent is not particularly limited, and can be adjusted as appropriate depending on the film formation conditions, the desired thickness and performance of the release layer, etc. However, in order to maintain the viscosity of the aqueous release coating agent appropriately and to exhibit good release layer formation ability, it is preferably 99.5 to 80% by mass, more preferably 99 to 90% by mass, and particularly preferably 99 to 90% by mass.

[0045] (Additives) In order to improve various release layer properties such as adhesion and chemical resistance, additives may be added to the aqueous release coating agent of the present invention, up to a maximum of about 30 parts by mass per 100 parts by mass of the acid-modified polyolefin resin (A) and compound (B). Examples of such additives include various crosslinking agents and other polymers.

[0046] As crosslinking agents, self-crosslinking agents, compounds having multiple functional groups that react with carboxyl groups within the molecule, and metal complexes having polyvalent coordination sites can be used. Of these, melamine compounds, urea compounds, epoxy compounds, carbodiimide compounds, oxazoline compounds, zirconium salt compounds, and silane coupling agents are preferred. These crosslinking agents may also be used in combination.

[0047] Other polymers are not particularly limited. Examples 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 other polymers can be added as aqueous dispersions or solutions. Alternatively, two or more types may be used in mixture form.

[0048] The aqueous release coating agent of the present invention may contain a pigment or dye depending on the intended use, or it may be added to paints or inks. The pigment or dye used is not particularly limited, and commonly used ones may be appropriately selected depending on the type of paint or ink.

[0049] 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, as well as organic pigments such as azo, diazo, condensed azo, thioindigo, indanthrone, quinacridone, anthraquinone, benzimidazole, perylene, perinone, phthalocyanine, halogenated phthalocyanine, anthrapyridine, and dioxazine.

[0050] Examples of dyes include direct dyes, reactive dyes, acid dyes, cationic dyes, vat dyes, and mordant dyes. Pigments or dyes can be used individually or in combination of two or more types.

[0051] The aqueous release coating agent of the present invention may optionally contain various agents such as leveling agents, defoaming agents, anti-smudge agents, thickeners, pigment dispersants, and ultraviolet absorbers. Furthermore, other organic or inorganic compounds may be added, provided that they do not impair the storage stability of the aqueous release coating agent.

[0052] (Laminated structure) The laminate of the present invention is formed by laminating a release layer on at least a portion of at least one side of a substrate using the aqueous release coating agent of the present invention.

[0053] The aqueous release coating agent of the present invention can be uniformly coated onto the surface of various substrates 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, brush application, etc., and after setting at room temperature as necessary, subjecting it to drying or heat treatment for drying and baking to form a uniform release layer that adheres closely to the surface of various substrates.

[0054] For heating in this process, a conventional hot air circulation oven or infrared heater can be used. The heating temperature can be used in the range of approximately 50 to 200°C. The release layer formed from the aqueous release coating agent of the present invention achieves sufficient adhesion and release properties to the substrate after drying at 100 to 180°C. In addition, an aging treatment may be performed at 60 to 80°C to advance the reaction.

[0055] Since the aqueous release coating agent of the present invention has good adhesion to various materials, by removing the aqueous medium from the aqueous release coating agent as described above, a laminate with good adhesion to the substrate can be produced, and this laminate can be used as a release film or release sheet.

[0056] The substrates constituting the laminate of the present invention include, but are not particularly limited to, paper, synthetic paper, films and molded articles of various thermoplastic resins, glass, metal, metal foil such as aluminum foil (including rust-preventive treatment and electrolyte-resistant coating treatment), and plastics. The aqueous release coating agent of the present invention can obtain excellent adhesion even under heat treatment conditions at relatively low temperatures, and can therefore 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. Furthermore, synthetic paper and thermoplastic resin films are preferred as the shape of the substrate, and thermoplastic resin films are particularly preferred.

[0057] Examples of thermoplastic resin films used as a base material include films or laminates made of 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, or mixtures thereof.

[0058] Thermoplastic resin films can be either unstretched or stretched films, and their manufacturing methods are not limited. The thickness of the thermoplastic resin film is also not particularly limited, but typically ranges from 5 to 500 μm.

[0059] 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.

[0060] Thermoplastic resin films may be subjected to various functional treatments such as barrier coatings, easy-adhesion coatings, antistatic coatings, and UV-shielding coatings, as well as various vapor deposition treatments such as silica, alumina, and aluminum. The aqueous release agent of the present invention also exhibits good adhesion to surfaces treated with the above-mentioned processes.

[0061] A coating obtained by removing the aqueous medium from the aqueous release coating agent of the present invention can be used as the release layer of the present invention. The thickness of the release layer is not particularly limited, but is preferably 0.1 to 20 μm, more preferably 0.2 to 15 μm, even more preferably 0.3 to 10 μm, and particularly preferably 0.5 to 5 μm. If the thickness is less than 0.1 μm, the release properties may deteriorate, and if it exceeds 20 μm, the release layer may crack or the drying time may be prolonged.

[0062] The release layer of the present invention has good release properties for various materials, and can therefore be used with various materials (mating materials). Furthermore, by laminating the release layer onto a substrate, it can be used as a laminate with release properties for applications such as release films and release sheets. The release layer of the present invention can be suitably used as a protective material for adhesive materials and liquid crystal display components (polarizing plates, phase difference polarizing plates, phase difference plates, etc.), as a process material for prepregs used in the pressing process of printed circuit boards and structural materials for aircraft, etc., and as a release layer for transfer printing. In particular, it can be suitably used with adhesive materials.

[0063] Examples of adhesive materials include adhesive sheets, 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, or a substrate may not be used. The components of the adhesive are not particularly limited, but examples include acrylic adhesives, natural rubber adhesives, synthetic rubber adhesives, and silicone adhesives. The adhesive may contain tackifiers such as rosin-based, coumarone-indene-based, terpene-based, petroleum-based, styrene-based, phenol-based, and xylene-based agents. Examples of substrates for the adhesive layer include paper, cloth, and resin materials.

[0064] Release layers used for adhesive materials are required to be able to be peeled off with a desired peel strength, depending on the intended use and handling during the process. 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 or less. In the release layer 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 resin layer of a release sheet is measured at 25°C, with a peel angle of 180 degrees and a peel speed of 300 mm / min, the peel strength between the adhesive layer and the resin layer can be 4.0 N / cm or less, more preferably 3.5 N / cm or less, even more preferably 3.0 N / cm or less, and most preferably 2.5 N / cm or less. If the peel strength with respect to acrylic adhesive materials exceeds 4.1 N / cm, when peeling the laminate with the release layer from the adhesive material, there may be high resistance and it may not peel off properly, or when peeling multiple layers, other layers may peel off, making it difficult to use as a release layer for acrylic adhesive materials. Furthermore, in the fields of so-called "light peeling" and "ultra-light peeling," there is a demand for materials with an initial peel strength of 0.05 to 0.2 N / cm or less when applied to acrylic adhesive materials, as well as a peel strength of 0.05 to 0.2 N / cm or less after 24 hours at 70°C.

[0065] In the present invention, it is preferable that there is no blocking when the release layer, which is laminated thereon, is made into a roll-shaped winding of a release film or release sheet.

[0066] The release layer of the present invention preferably has excellent transparency for quality control during the production process, such as visual inspection of air bubbles and foreign matter when bonded to the mating material. Transparency can be confirmed by measuring the haze of the release layer.

[0067] Furthermore, when laminates are used as release sheets, they are often handled by being wound into rolls, so it is preferable that the components forming the release layer do not migrate to the back of the substrate. Such migration of release layer components to the back, i.e., detachment of release layer components from the substrate, can be easily judged by applying adhesive tape to the release layer, holding it under certain conditions, peeling off the adhesive tape, and observing the degree of decrease in the adhesiveness of the tape. In other words, the less the adhesiveness of the adhesive tape decreases, the less the release layer has detached. If the adhesiveness of the adhesive tape decreases little, it can be determined that sufficient adhesiveness remains even when it is reapplied. Moreover, if sufficient adhesiveness is maintained when the same evaluation is performed in a high-temperature environment, it can be said that the release layer has excellent heat resistance. If the adhesive surface of the adhesive tape is contaminated by the release layer, or if the surface of the adhesive tape becomes significantly rough during peeling, the re-adhesion of the adhesive tape decreases, impairing its performance as an adhesive tape. Therefore, it is preferable that the decrease in the peeling force of the adhesive tape is suppressed as much as possible, i.e., that the residual adhesion rate is high.

[0068] Examples of sheet-like structures for laminates having a release layer according to the present invention include rubber sheets such as silicone rubber, fluororubber, and urethane rubber; synthetic leather made of vinyl chloride and urethane; ion exchange membranes made of polymer electrolytes such as perfluorosulfonic acid resin; ceramic green sheets made of dielectric ceramics and glass; and heat dissipation sheets containing heat dissipation materials.

[0069] When the release layer of the present invention is used for transfer printing, various functional layers such as a printing layer, electrode, and protective layer are formed by coating the release layer. The functional layer on the release layer is then transferred to the transfer target by heating and pressing it against the transfer target, and then the release layer is peeled off from the functional layer. In this way, the release layer of the present invention can be used for what is also called stamping foil. Examples of functional layers include metallic foil, pigment foil, multicolor printing foil, hologram foil, electrostatic discharge foil, and half-mirror metallic foil.

[0070] The release layer 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, the surface of printed circuit boards, display substrates, and the like. [Examples]

[0071] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto. The various characteristics were measured or evaluated using the following methods.

[0072] 1. Characteristics of acid-modified polyolefin resins (1) Composition 1 The results were obtained by 1H-NMR analysis (Varian, 300 MHz). The measurements were taken at 120°C using orthodichlorobenzene (d4) as the solvent.

[0073] (2) Melt Flow Rate (MFR) Measurements were taken according to the method described in JIS 6730 (190°C, 2160g load).

[0074] (3) Melting point Measurements were taken using a DSC (Perkin Elmer DSC-7) at a heating rate of 10°C / min.

[0075] (4) Weight average molecular weight GPC analysis was performed using a Shimadzu LC-10AD column (two SHODEX KF-804L columns and one KF805L column linked together). Tetrahydrofuran was used as the eluent, and measurements were taken at a flow rate of 1 ml / min and 40°C. Approximately 10 mg of copolymer was dissolved in 5.5 mL of tetrahydrofuran and filtered through a PTFE membrane filter to prepare the sample for measurement. The weight-average molecular weight was determined from a calibration curve created using polystyrene standard samples.

[0076] 2. Properties of aqueous dispersions of acid-modified polyolefin resins and aqueous release coatings (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.

[0077] (2) Average particle size of aqueous dispersion The number-average particle size (mn) and weight-average particle size (mw) were determined using a Microtrac particle size distribution analyzer UPA150 (MODEL No. 9340, dynamic light scattering method) manufactured by Nikkiso Co., Ltd. The refractive index of the resin used for particle size calculation was assumed to be 1.50.

[0078] 3. Characteristics of the release layer and laminate In the following evaluations, biaxially oriented polyethylene terephthalate film (Unitika Corporation's Emblet S-50, 50 μm thick, hereinafter referred to as "PET film") and aluminum foil (Mitsubishi Aluminum Corporation, 12 μm thick, hereinafter referred to as "aluminum foil") were used as the thermoplastic resin film base material.

[0079] (1) Adhesion to substrate (tape peel test) A water-based release agent was applied to the corona-treated surface of a PET film or aluminum foil using a Meyer burr to achieve a dry film thickness of 3 μm, and then dried at 60°C for 30 seconds. A TESA tape (TESA 7475, manufactured by Tesa Tape Co., Ltd.) was applied to the release layer surface of the laminated film immediately after drying, and the degree of peeling when the tape was peeled off in one swift motion was visually evaluated according to the following criteria. ○: No peeling at all △: Partial peeling ×: Completely peeled off

[0080] (2) Haze (cloudy value) In accordance with JIS K7105, the haze (%) was measured using an NDH2000 "turbidity and cloudiness meter" manufactured by Nippon Denshoku Industries Co., Ltd. A PET film with a haze of 1.0% was coated with a coating agent using a Meyer bur so that the thickness of the release layer after drying was 2 μm, and then dried at 100°C for 30 seconds to produce a coated film. The haze of the entire coated film produced in this way was measured. ○: 1-5% △: More than 5%, less than 10% ×: More than 10%

[0081] (3) Evaluation of blocking resistance The aqueous release agent of the present invention was applied to a PET film using a Meyer bar so that the thickness of the release layer after drying was 5 μm, and it was dried at 100°C for 30 seconds. With the PET film placed on top of the coated surface, a load of 0.1 MPa was applied and it was left for 24 hours in an atmosphere of 30°C and 65% RH, and its blocking resistance was evaluated in the following three stages. ○: Peel off the PET film by gently lifting it. △: The PET film can be peeled off by pulling it. ×: The PET film is torn, or delamination at the interface or cohesively from the release layer is observed.

[0082] (4) Mold releasability A PET film was coated with the release coating agent of the present invention using a Meyer bar so that the coating thickness after drying was 0.5 μm. After drying at 100°C for 30 seconds, adhesive tape (Nitto Denko No. 31B / acrylic adhesive) was attached to the release layer surface. This sample was then cut into 25 mm widths, and the release properties were evaluated by measuring the peel strength of the release layer using a tensile testing machine (Intesco Precision Universal Material Testing Machine 2020) in a constant temperature chamber at 25°C at a tensile speed of 300 mm / min and a peel angle of 180 degrees. A peel strength of 4.0 N / 25 mm or less was considered acceptable.

[0083] (5) Release properties after heat treatment Similar to "(4) Release Properties," a sample was prepared by applying and drying a coating agent on a PET film. After attaching adhesive tape to the release layer surface, the sample was heat-treated at 70°C for 24 hours. The release properties were then evaluated by measuring the peel strength of the release layer under the same conditions as "(4) Release Properties." A peel strength of 5.0 N / 25 mm or less was considered acceptable.

[0084] (6)Residual adhesion rate A 25mm wide, 150mm long adhesive tape, peeled from the release film surface in the peel strength test described in "(4) Release Properties," was applied to the corona-treated surface of a PET film and left for 20 hours under a 2kPa load at 25°C. The peel strength between the adhesive tape and the film was then measured in the same manner as in "(4) Release Properties." This measured peel strength was defined as F1. Meanwhile, an unused 50mm wide, 150mm long adhesive tape (Nitto Denko No. 31B) was applied to the corona-treated surface of a PET film and left for 20 hours under a 2kPa load at 25°C. The peel strength between the adhesive tape and the film was then measured in the same manner as in "(4) Release Properties," and this measured peel strength was defined as F2. The residual adhesion rate was then obtained using the following formula. Residual adhesion rate (%)=(F1 / F2)×100 If the adhesive surface of adhesive tape becomes contaminated with the release film, the re-adhesion properties of the tape will decrease, impairing its performance as an adhesive tape. In other words, a higher residual adhesion rate is preferable. A residual adhesion rate of 80% or higher was set as the acceptable standard.

[0085] (7) Liquid state immediately after manufacturing The condition of the coating agent immediately after manufacturing was checked. ○: No aggregates or gels. △: Some aggregates present (aggregates at a level that allows for coating) ×: Gelation or large amounts of aggregates

[0086] (8) Release performance 14 days after manufacture After confirming the release properties of the coating agent immediately after manufacturing and after heat treatment, the release properties were checked again after being left at 25°C for 14 days. ○: Performance equivalent to that immediately after manufacturing. △: The release properties after heat treatment become 10-15% stronger compared to the results immediately after manufacturing. ×: The release properties after heat treatment become 16% or more stronger than the results immediately after manufacturing.

[0087] The following materials were used as raw materials for the water-based release coating agent. 1. Acid-modified polyolefin resin A1: Arkema Bondine HX-8290 A2: Arkema Bondine TX-8030 A3: Arkema Bondine LX-4110 A4: Dow Chemical Company Primacol 5980I

[0088] A5: 280 g of propylene-butene copolymer (propylene / butene = 80 / 20 mass%) was heated and melted in a four-necked flask 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 reaction was continued 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 further washed several times with acetone to remove unreacted maleic anhydride, and then dried under reduced pressure in a vacuum dryer to obtain acid-modified polyolefin resin (A4).

[0089] 2. Aqueous dispersion of acid-modified polyolefin resin Aqueous dispersion of A1 (E-1): Using a stirrer equipped with a sealed, pressure-resistant 1-liter glass container with a heater, 60.0 g of acid-modified polyolefin resin (A1), 60.0 g of isopropanol (IPA), 2.2 g of triethylamine (TEA), and 177.8 g of distilled water were placed in the glass container and stirred at a rotation speed of 300 rpm. No sedimentation of resin granules was observed at the bottom of the container, and it was confirmed that the resin was suspended. Maintaining this state, the heater was turned on after 10 minutes to heat the mixture. The system temperature was then maintained at 120°C and stirred 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 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 milky white, uniform aqueous dispersion of acid-modified polyolefin resin (A1) E-1.

[0090] Aqueous dispersion of A2 (E-2): Using a stirrer equipped with a sealed, pressure-resistant 1L glass container with a heater, 100.0g of acid-modified polyolefin resin (A2), 150.0g of IPA, 6.0g of TEA, and 244.0g of distilled water were placed in the glass container and stirred at a rotation speed of 300 rpm. No sedimentation of resin granules was observed at the bottom of the container, and it was confirmed that the contents were suspended. Maintaining this state, the heater was turned on after 10 minutes to heat the mixture. The system temperature was then maintained at 130°C and stirred 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 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 milky white, uniform aqueous dispersion of acid-modified polyolefin resin (A2) E-2.

[0091] A3 aqueous dispersion (E-3): An aqueous dispersion of acid-modified polyolefin resin (A3) E-3 was obtained by the same procedure as for the aqueous dispersion of A2, except that acid-modified polyolefin resin (A3) was used.

[0092] A4 aqueous dispersion (E-4): Polyolefin resin (A4) was used. Using a stirrer equipped with a sealed, pressure-resistant 1L glass container with a heater, 60.0g of A4, 16.8g of TEA, and 223.2g of distilled water were placed in the glass container, and the mixture was stirred at a rotation speed of 300 rpm. No sedimentation of resin granules was observed at the bottom of the container, and it was confirmed that the contents were suspended. Maintaining this state, the heater was turned on after 10 minutes to heat the mixture. The system temperature was then maintained at 130°C and stirred 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 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 white aqueous dispersion E-4.

[0093] A5 aqueous dispersion (E-5): Using a stirrer equipped with a sealed, pressure-resistant 1L glass container with a heater, 60.0g of 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 placed in the glass container and stirred at a rotation speed of 300 rpm. No resin sedimentation was observed at the bottom of the container, and it was confirmed that the resin was suspended. Maintaining this state, the heater was turned on after 10 minutes to heat the mixture. The system temperature was then maintained at 160°C and stirred for another 60 minutes. After that, the mixture was cooled by air cooling until the internal temperature reached 80°C. The container was then opened, and 45.0g of tetrahydrofuran, 5.0g of N,N-dimethylethanolamine, and 30.0g of distilled water were added. The container was then sealed, and the system temperature was maintained at 140°C at a rotation speed of 300 rpm and stirred for another 60 minutes. Subsequently, the mixture was cooled to 25°C while being stirred at a rotation speed of 300 rpm using air cooling. Then, it was 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 of acid-modified polyolefin resin (A5) E-5. At this point, almost no resin remained on the filter.

[0094] Tables 1 and 2 show the composition and properties of acid-modified polyolefin resins (A1) to (A5), as well as the properties of their aqueous dispersions.

[0095] [Table 1]

[0096] [Table 2]

[0097] 3. Organotitanium compounds • Organotitanium compound (G-1) · Titanium diisopropoxybis(triethanolamine) TC-400: Manufactured by Matsumoto Fine Chemical Co., Ltd. (Ti content: 8% by mass, chelate type) • Organotitanium compounds (G-2) • Titanium diethanolamine TC-500: Manufactured by Matsumoto Fine Chemical Co., Ltd. (Ti content: 8% by mass, chelate type) • Organotitanium compounds (G-3) • Tetraisopropyl titanate TC-800: Manufactured by Matsumoto Fine Chemical Co., Ltd. (Ti content: 16.9% by mass, alkoxide)

[0098] 4. Organozirconium compounds Zirconium-based compounds (G-4) ··· Zirconium lactate ammonium ZC-300: Manufactured by Matsumoto Fine Chemical Co., Ltd. (Zr content: 2.7% by mass, chelate type)

[0099] 5. Aqueous solution of crosslinking agent (G-5) WS-700: Nippon Shokubai Co., Ltd.'s Epocross WS-700 (aqueous solution of oxazoline compound containing 2-isopropenyl-2-oxazoline, solid content concentration 25% by mass) was used.

[0100] Example 1 400 parts by mass of an aqueous dispersion (E-1) of acid-modified polyolefin resin (A1) and 6.25 parts by mass of an organotitanium compound (G-1) were mixed (the mass ratio of acid-modified polyolefin solids to titanium was 100 / 0.5), and the mixture was stirred at 25°C for 5 minutes to obtain an aqueous release coating agent.

[0101] Examples 2-17, Comparative Examples 1-8 As shown in the table, an aqueous release coating agent was obtained by performing the same procedure as in Example 1, except that the type of acid-modified polyolefin resin and the mass ratio of organotitanium compounds were changed so that the mass ratio of the acid-modified polyolefin solids to the titanium contained in the organotitanium compounds was as shown in the table.

[0102] The composition and properties of the coating agents in the examples and comparative examples are shown in the table.

[0103] [Table 3]

[0104] [Table 4]

[0105] [Table 5]

[0106] As shown in Examples 1 to 20, the aqueous release coating agent containing an acid-modified polyolefin resin (A) and an organotitanium compound (B) exhibited excellent substrate adhesion, blocking resistance, release properties, and release properties after heat treatment due to the inclusion of the organotitanium compound (B).

[0107] Each comparative example had the following problems. The aqueous release coating agents in Comparative Examples 1-3 did not contain organotitanium compound (B), and therefore exhibited inferior release properties, release properties after heat treatment, and blocking. The aqueous release coating agents in Comparative Examples 4 and 5 had inferior substrate adhesion, release properties, release properties after heat treatment, blocking properties, and performance after storage because their content of organotitanium compounds was outside the scope of the present invention. The aqueous release agent in Comparative Example 6 was a conventional non-silicone release agent, and although it exhibited good substrate adhesion, blocking properties, and liquid stability, its release properties after heat treatment were poor. The aqueous release agent in Comparative Example 7 was an organozirconium, although it was a transition metal, and therefore exhibited inferior substrate adhesion, blocking resistance, release properties, and release properties after heat treatment. Haze measurement revealed whitening due to aggregates.

Claims

1. An aqueous release coating agent comprising an acid-modified polyolefin resin (A), an organotitanium compound (B), and an aqueous medium, wherein the mass ratio of the acid-modified polyolefin resin (A) to titanium is 100 / 0.5 to 100 / 20.

2. The aqueous release coating agent according to claim 1, wherein the organotitanium compound (B) is a chelate-type organotitanium compound.

3. The aqueous release coating agent according to claim 2, wherein the chelate-type organotitanium compound is titanium diisopropoxybis(triethanolamine) or titanium diethanolamine.

4. A release layer obtained by removing the aqueous medium from an aqueous release coating agent according to any of claims 1 to 3.

5. A laminate comprising a release layer according to claim 4 laminated on at least a portion of at least one side of a base material.

6. The laminate according to claim 5, wherein the base material is a thermoplastic resin film or a metal foil.

Images