Heat resistant adhesive film

Abstract

Provided is a heat resistant adhesive film to be used in a high-temperature heat treatment step wherein said film can be peeled off without leaving adhesive residue on an adherend, even when the adhesive force to the adherend is increased via a high-temperature environment. This adhesive film is obtained by layering a base material, and, on at least one surface of the base material, an easily-adhesive layer and a silicone-based adhesive agent layer, in that order, and is characterized in that the easily-adhesive layer is a cured product obtained by heat curing a composition including: an epoxy compound (A) selected from the group consisting of a cycloalkene oxide type alicyclic epoxy compound (A-i) and a glycidylamine type epoxy compound (A-ii); an acid anhydride (B); and a polyol compound (C).

Description

Heat-resistant adhesive film

[0001] The present invention relates to a heat-resistant adhesive film used in a high-temperature heat treatment process.

[0002] Conventionally, heat-resistant adhesive films have been used that are made by coating and laminating a silicone-based adhesive with excellent heat resistance onto a plastic film such as a polyester film or a polyimide film, or a metal foil such as a copper foil or an aluminum foil.

[0003] These heat-resistant adhesive films are also used appropriately for protecting and fixing electronic components in manufacturing processes involving semiconductor devices that are subjected to high-temperature environments.

[0004] For example, Patent Document 1 discloses a heat-resistant adhesive film used in the manufacturing process of a QFN (Quad Flat Non-leaded package) package, which is one type of semiconductor package. This heat-resistant adhesive film used in the semiconductor package manufacturing process is an adhesive film that is attached to a lead frame when resin-encapsulating a semiconductor chip, and is preferably one that has low adhesive strength at room temperature from the standpoint of ease of attachment to the lead frame and reworkability, and whose adhesive strength increases in a high-temperature environment to prevent resin leakage during the high-temperature resin-encapsulation process, which reaches 175 to 200°C.

[0005] Generally, a silicone-based pressure-sensitive adhesive layer has poor adhesion to a substrate such as a plastic film or metal foil, and therefore, a primer layer (an easy-adhesion layer) is generally provided between the substrate and the silicone-based pressure-sensitive adhesive layer to improve adhesion (see Patent Document 2).

[0006] However, when the film is exposed to a high temperature environment after being attached to the adherend, or when a silicone-based adhesive layer is used whose adhesive strength increases in an even higher temperature environment, when the adhesive film is peeled off after cooling, a "residual adhesive" phenomenon in which the adhesive layer adheres to the adherend side often occurs.

[0007] Patent Documents 3 and 4 disclose heat-resistant adhesive sheets in which an easy-adhesion layer made of a specific material is provided between a substrate and a silicone-based pressure-sensitive adhesive layer, so that when the protective sheet is peeled off from the adherend even after exposure to a high-temperature environment, the protective sheet can be peeled off without leaving any adhesive residue on the adherend. However, when a silicone-based pressure-sensitive adhesive layer whose adhesive strength increases in a high-temperature environment is used, adhesive residue may occur depending on the high-temperature processing conditions and the adherend, and further improvement was necessary.

[0008] JP 2012-151360 A JP 2002-338890 A JP 2014-213545 A JP 2014-221877 A

[0009] The present invention aims to provide a heat-resistant adhesive film used in heat treatment processes in high-temperature environments, such as semiconductor device manufacturing processes, which has an excellent effect of suppressing adhesive residue on an adherend when peeled from the adherend, even if the heat-resistant adhesive film has a silicone adhesive layer that exhibits increased adhesive strength to the adherend in high-temperature environments.

[0010] As a result of intensive research into achieving the above-mentioned object, the present inventors have found that by forming an easy-adhesion layer containing a cured product obtained by thermally curing a composition containing an epoxy compound (A) selected from the group consisting of cycloalkene oxide-type alicyclic epoxy compounds (A-i) and glycidyl amine-type epoxy compounds (A-ii), an acid anhydride (B), and a polyol compound (C) on one surface of a substrate, and then coating a silicone-based pressure-sensitive adhesive composition thereon to form a silicone-based pressure-sensitive adhesive layer by thermal crosslinking, unreacted hydroxyl groups contained in excess in the easy-adhesion layer react with reactive functional groups in the silicone-based pressure-sensitive adhesive composition, thereby achieving very strong adhesion between the substrate and the silicone-based pressure-sensitive adhesive layer, and also that the cured product of the easy-adhesion layer has high heat resistance and can maintain adhesion even when exposed to a high-temperature environment, thereby completing the present invention.

[0011] The first invention is an adhesive film comprising a substrate and an easy-adhesion layer and a silicone-based adhesive layer laminated in this order on at least one surface of the substrate, wherein the easy-adhesion layer is a cured product obtained by thermally curing a composition containing an epoxy compound (A) selected from the group consisting of cycloalkene oxide-type alicyclic epoxy compounds (A-i) and glycidyl amine-type epoxy compounds (A-ii), an acid anhydride (B), and a polyol compound (C).

[0012] A second invention is the pressure-sensitive adhesive film according to the first invention, characterized in that the polyol compound (C) is a silicate hydrolyzate.

[0013] A third invention is the pressure-sensitive adhesive film according to the first invention, characterized in that the polyol compound (C) is an acrylic polyol.

[0014] A fourth invention is a pressure-sensitive adhesive film according to any one of the first to third inventions, characterized in that in the composition comprising an epoxy compound (A) selected from the group consisting of cycloalkene oxide-type alicyclic epoxy compounds (A-i) and glycidyl amine-type epoxy compounds (A-ii), an acid anhydride (B), and a polyol compound (C) that forms the easy-adhesion layer, the mass ratio of the total mass of the epoxy compound (A) and the acid anhydride (B) to the mass of the polyol compound (C) {[(A) + (B)]:(C)} is 10:90 to 90:10.

[0015] A fifth invention is a pressure-sensitive adhesive film according to any one of the first to fourth inventions, characterized in that in the composition comprising an epoxy compound (A) selected from the group consisting of cycloalkene oxide-type alicyclic epoxy compounds (A-i) and glycidyl amine-type epoxy compounds (A-ii), which forms the easy-adhesion layer, an acid anhydride (B), and a polyol compound (C), the molar ratio of the epoxy groups of the epoxy compound (A) to the acid groups of the acid anhydride (B) {[epoxy groups of (A)]:[acid groups of (B)]} is 20:80 to 80:20.

[0016] A sixth invention is the pressure-sensitive adhesive film according to any one of the first to fifth inventions, characterized in that the easy-adhesion layer has a thickness of 0.05 to 3.00 μm.

[0017] According to the present invention, an easy-adhesion layer containing a cured product obtained by thermally curing a composition containing an epoxy compound (A) selected from the group consisting of cycloalkene oxide-type alicyclic epoxy compounds (A-i) and glycidyl amine-type epoxy compounds (A-ii), an acid anhydride (B), and a polyol compound (C) is formed on one side of a substrate, and a silicone-based pressure-sensitive adhesive composition is then laminated and coated thereon to form a silicone-based pressure-sensitive adhesive layer by thermal crosslinking. As a result, unreacted hydroxyl groups contained in the easy-adhesion layer in excess react with reactive functional groups in the silicone-based pressure-sensitive adhesive composition, resulting in very strong adhesion between the substrate and the silicone-based pressure-sensitive adhesive layer. In addition, the cured product of the easy-adhesion layer has high heat resistance and can maintain adhesion even when exposed to a high-temperature environment. Therefore, it is possible to provide a heat-resistant pressure-sensitive adhesive film that is excellent in preventing adhesive residue on the adherend when peeled from the adherend, even in cases where the adhesive strength to the adherend increases in a high-temperature environment.

[0018] 1 is a cross-sectional schematic view showing one embodiment of a heat-resistant adhesive film of the present invention.

[0019] Hereinafter, an embodiment of the present invention will be described.

[0020] The heat-resistant adhesive film of the present invention has a configuration in which an easy-adhesion layer and a silicone-based adhesive layer are laminated in this order on at least one surface of a substrate, and the easy-adhesion layer is an adhesive film containing a cured product obtained by thermally curing a composition containing an epoxy compound (A) selected from the group consisting of cycloalkene oxide-type alicyclic epoxy compounds (A-i) and glycidyl amine-type epoxy compounds (A-ii), an acid anhydride (B), and a polyol compound (C).

[0021] (Substrate) As the substrate constituting the heat-resistant adhesive film of the present invention, a plastic film or metal foil that can withstand high-temperature heating can be used, but it is preferable to use a plastic film from the viewpoint of ease of handling as an adhesive film and flexibility.

[0022] When a plastic film is used as the substrate, the material is preferably a heat-resistant synthetic resin having a melting point of 250°C or higher, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polyetherimide (PEI), polysulfone (PSF), polyethersulfone (PES), polyphenylene sulfide (PPS), polyetheretherketone (PEEK), etc. Among these heat-resistant synthetic resin films, it is more preferable to use a polyimide film, which has excellent dimensional stability at high temperatures.

[0023] The thickness of the substrate is preferably in the range of 5 to 250 μm, more preferably 10 to 150 μm, and even more preferably 20 to 100 μm, from the viewpoint of the processability and handleability of the PSA film. By making the thickness of the substrate 5 μm or more, preferably 10 μm or more, and even more preferably 20 μm or more, the substrate is provided with stiffness, improving the coatability of the PSA layer and the handleability of the PSA film when applied. On the other hand, by making the thickness of the substrate 250 μm or less, preferably 150 μm or less, and even more preferably 100 μm or less, the appropriate flexibility of the substrate during rework improves releasability, enhancing the protection of the adherend during peeling, and reducing substrate costs.

[0024] The surface of the substrate on which the adhesive layer and pressure-sensitive adhesive layer are to be formed may be subjected to treatment such as corona discharge treatment, ultraviolet irradiation treatment, plasma treatment, etc., as required.

[0025] (Easy-Adhesion Layer) The easy-adhesion layer constituting the heat-resistant adhesive film of the present invention is a cured product obtained by thermally curing a composition containing an epoxy compound (A) selected from the group consisting of cycloalkene oxide-type alicyclic epoxy compounds (A-i) and glycidyl amine-type epoxy compounds (A-ii), an acid anhydride (B), and a polyol compound (C).

[0026] The adhesive layer composition containing the above-mentioned (A), (B), and (C) is mixed with a solvent or the like to form a coating liquid, which is then uniformly coated on a substrate, the solvent is dried, and the coating liquid is thermally cured to form an adhesive layer. The adhesive layer is cured by thermal curing, whereby the epoxy compound (A) reacts with the acid anhydride (B), and the acid anhydride (B) reacts with the polyol compound (C), respectively.

[0027] The adhesive layer contains an epoxy cured product that has high adhesiveness to synthetic resins and metals, and therefore adheres firmly to substrates such as plastic films and metal foils.

[0028] Next, a silicone-based pressure-sensitive adhesive composition is coated and laminated on the heat-cured easy-adhesion layer, and a silicone-based pressure-sensitive adhesive layer is formed by thermal crosslinking. In the thermal crosslinking step of the silicone-based pressure-sensitive adhesive layer, unreacted hydroxyl groups contained in excess in the polyol compound in the easy-adhesion layer react with reactive functional groups (silanol (SiOH) groups, hydrosilyl (SiH) groups, etc.) of the main agent or crosslinking agent component in the silicone-based pressure-sensitive adhesive composition, resulting in strong adhesion between the easy-adhesion layer and the silicone-based pressure-sensitive adhesive layer. Therefore, the adhesion between the substrate and the silicone-based pressure-sensitive adhesive layer is strong.

[0029] Furthermore, since the easy-adhesion layer contains a cured product of a cycloalkene oxide-type alicyclic epoxy compound and / or a glycidyl amine-type epoxy compound, which have high heat resistance, and an acid anhydride, the easy-adhesion layer can maintain adhesion to the substrate and the silicone-based pressure-sensitive adhesive layer even when exposed to a high-temperature environment.

[0030] From the viewpoint of actual roll-to-roll productivity, the adhesive layer of the present invention is required to cure in a short time and have a tack-free surface (a non-sticky state). The composition of the adhesive layer uses a cycloalkene oxide-type alicyclic epoxy compound and / or a glycidylamine-type epoxy compound, which are more reactive than commonly used non-glycidylamine-type bisphenol-type epoxy resins, and therefore has low-temperature fast curing properties, and an adhesive layer with a tack-free surface can be easily formed.

[0031] Of the epoxy compounds (A) used in the easy-adhesion layer composition, the cycloalkene oxide-type alicyclic epoxy compound (A-i) is an epoxy compound in which an epoxy group is formed between two adjacent carbon atoms constituting an alicyclic ring (aliphatic hydrocarbon ring), and has one or more epoxy groups in one molecule.Specific examples of the cycloalkene oxide type alicyclic epoxy compound (A-i) include 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3',4'-epoxy-6'-methylcyclohexylcarboxylate, 2,3-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate, 4-(3,4-epoxy-5-methylcyclohexyl)butyl-3',4'-epoxycyclohexylcarboxylate, hydroxylate, 3,4-epoxycyclohexylethylene oxide, cyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-6'-methylcyclohexylcarboxylate, bis-epoxydicyclopentadienyl ether, bis-epoxycyclohexyl adipate, 3,4-dimethyl-1,2-epoxycyclohexane, 3,5-dimethyl-1,2-epoxycyclohexane, 3-methyl-5-t-butyl-1,2-epoxycyclohexane, octadecyl cyclohexyl-2,2-dimethyl-3,4-epoxycyclohexylcarboxylate, N-butyl-2,2-dimethyl-3,4-epoxycyclohexylcarboxylate, cyclohexyl-2-methyl-3,4-epoxycyclohexylcarboxylate, N-butyl-2-isopropyl-3,4-epoxy-5-methylcyclohexylcarboxylate, octadecyl-3,4-epoxycyclohexylcarboxylate, 2-ethylhexyl-3',4'-epoxycyclohexylcarboxylate, 4,6-dimethyl-2,3- epoxycyclohexyl-3',4'-epoxycyclohexylcarboxylate, diethyl-4,5-epoxy-cis-1,2-cyclohexyldicarboxylate, di-n-butyl-3-t-butyl-4,5-epoxy-cis-1,2-cyclohexyldicarboxylate, polycyclic saturated hydrocarbons having an epoxy group (the polycyclic saturated hydrocarbon skeleton is preferably one in which cyclic saturated hydrocarbons are bonded to each other via two or more atoms, and examples of such polycyclic saturated hydrocarbon skeletons include hydrindane and dicyclonorbornane).The polycyclic saturated hydrocarbon having an epoxy group has an epoxy group bonded to the polycyclic saturated hydrocarbon skeleton, and particularly preferred examples include tetrahydroindene diepoxide, etc.), and silane coupling agents having an epoxy group (for example, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc.). Of these, it is more preferable to use a cycloalkene oxide-type alicyclic epoxy compound having two or more epoxy groups per molecule. Furthermore, the cycloalkene oxide-type alicyclic epoxy compound (A-i) can be used alone or in combination of two or more.

[0032] The epoxy equivalent of the cycloalkene oxide type alicyclic epoxy compound (A-i) is preferably 80 to 500 g / eq, more preferably 100 to 400 g / eq, even more preferably 120 to 300 g / eq, and still more preferably 120 to 250 g / eq, from the viewpoint of curability with a curing agent.

[0033] Of the epoxy compounds (A) used in the easy-adhesion layer composition, the glycidylamine type epoxy compound (A-ii) is an epoxy compound having a glycidyl group bonded to a nitrogen atom, and has two or more epoxy groups and one or more tertiary nitrogen atoms in one molecule. The glycidylamine type epoxy compound (A-ii) may be an aromatic epoxy compound or an alicyclic epoxy compound. Specific examples of the glycidylamine type epoxy compound (A-ii) include N,N-diglycidylaniline, N,N-diglycidyl-2-methylbenzeneamine, N,N-diglycidyl-4-(glycidyloxy)aniline, N,N,N',N'-tetraglycidyl-1,3-benzenedi(methanamine), 4,4'-methylenebis(N,N-diglycidylaniline), 4,4'-[1,4-phenylenebis(dimethylmethylene)]bis(N,N-diglycidylaniline). Examples of suitable glycidylamine epoxy compounds include 4,4'-[(1,4-phenylene)bisoxy]bis(N,N-diglycidylaniline), 4,4'-methylenebis(N,N-diglycidyl-2-methylaniline), 4,4'-methylenebis(N,N-diglycidyl-3-methylaniline), 4,4'-[1,4-phenylenebis(dimethylmethylene)]bis(N,N-bisglycidyl-2,6-dimethylaniline), and 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane. Among these, it is more preferable to use a glycidylamine epoxy compound having three or more epoxy groups per molecule. Furthermore, the glycidylamine epoxy compound (A-ii) may be used alone or in combination of two or more thereof.

[0034] The epoxy equivalent of the glycidylamine type epoxy compound (A-ii) is preferably 80 to 500 g / eq, more preferably 85 to 400 g / eq, even more preferably 90 to 300 g / eq, and still more preferably 95 to 150 g / eq, from the viewpoint of curability with a curing agent.

[0035] As the acid anhydride (B) used in the adhesive layer composition, known acid anhydrides used as various epoxy curing agents can be suitably used.

[0036] Examples of the acid anhydride (B) include phthalic anhydride, succinic anhydride, HET anhydride, Himic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydraphthalic anhydride, tetrabromophthalic anhydride, tetrachlorophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenotetracarboxylic anhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, cyclohexane-1,2-dicarboxylic anhydride, 4-methylcyclohexane-1,2-dicarboxylic anhydride, 5-(2,5-oxotetrahydrofuryl)-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, and silane coupling agents having an acid anhydride group and an alkoxysilane group (e.g., 3-trimethoxysilylpropylsuccinic anhydride, etc.).

[0037] The acid anhydride (B) may be any of the above acid anhydrides, which may be used alone or in combination of two or more kinds.

[0038] From the viewpoint of improving the tack-free property of the easy-adhesion layer, the blending ratio of the acid anhydride (B) to the total amount of the epoxy compound (A) is preferably such that the molar ratio of the epoxy group of the epoxy compound (A) to the acid group of the acid anhydride (B) {[epoxy group of (A)]:[acid group of (B)]} is in the range of 20:80 to 80:20.

[0039] The polyol compound (C) used in the easy-adhesion layer composition is a compound having two or more hydroxyl groups in one molecule.The hydroxyl groups of the polyol compound (C) react with reactive functional groups such as silanol groups (SiOH groups) and hydrosilyl groups (SiH groups) contained in the acid anhydride (B) of the easy-adhesion layer composition and the silicone-based pressure-sensitive adhesive composition, respectively, thereby contributing to the strong adhesion between the easy-adhesion layer and the silicone-based pressure-sensitive adhesive layer.

[0040] The polyol compound (C) is preferably a polymer (oligomer or polymer), and examples of organic polymers include acrylic polyol, polyester polyol, and polyether polyol. As the organic polymer polyol compound (C), acrylic polyol is more preferred from the viewpoint of further improving the adhesive transfer suppression effect. Furthermore, examples of inorganic polyol compounds (C) include silicate hydrolyzates.

[0041] Examples of the acrylic polyol include copolymers obtained by copolymerizing a polymerizable monomer having one or more hydroxyl groups in the molecule with another monomer copolymerizable therewith. Examples of the polymerizable monomer having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, 2,2-dihydroxymethylbutyl (meth)acrylate, polyhydroxyalkyl maleate, and polyhydroxyalkyl fumarate. Furthermore, examples of monomers copolymerizable therewith include (meth)acrylic acid, alkyl (C1 to C12) (meth)acrylate, maleic acid, alkyl maleate, fumaric acid, alkyl fumarate, itaconic acid, alkyl itaconate, styrene, α-methylstyrene, vinyl acetate, (meth)acrylonitrile, 3-(2-isocyanate-2-propyl)-α-methylstyrene, trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, etc. Acrylic polyols can be obtained by copolymerizing these monomers in the presence of a suitable solvent and a polymerization initiator.

[0042] Examples of the polyester polyol include polyester polyols obtained by condensation polymerization of a polyol and a polycarboxylic acid (polybasic acid), and polyester polyols obtained by ring-opening polymerization of lactones.

[0043] Examples of polyols used in the condensation polymerization to obtain the polyester polyol include ethylene glycol, diethylene glycol, 1,2-propanediol, 2-methyl-1,3-propanediol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,3,5-trimethyl-1,5-pentanediol, 1,6-hexanediol, 2-ethyl-1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 2 ,6-hexanediol, 1,8-octanediol, 1,4-cyclohexanedimethanol, 1,2-dimethylolcyclohexane, 1,3-dimethylolcyclohexane, 1,4-dimethylolcyclohexane, 1,12-dodecanediol, polybutadiene diol, neopentyl glycol, tetramethylene glycol, propylene glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,3-dihydroxyacetone, hexylene glycol, 1,2,6-hexanetriol, ditrimethylolpropane, mannitol, sorbitol, and pentaerythritol.

[0044] Examples of polycarboxylic acids used in the condensation polymerization to obtain the polyester polyol include oxalic acid, adipic acid, sebacic acid, fumaric acid, malonic acid, succinic acid, glutaric acid, azelaic acid, citric acid, 2,6-naphthalenedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, citraconic acid, 1,10-decanedicarboxylic acid, methylhexahydrophthalic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, tetrahydrophthalic anhydride, pyromellitic anhydride, and trimellitic anhydride.

[0045] Examples of lactones used in the ring-opening polymerization to obtain the polyester polyol include ε-caprolactone, δ-valerolactone, and γ-butyrolactone.

[0046] Examples of the polyether polyol include polyether polyols obtained by an addition reaction of a cyclic ether compound to a polyol, and polyether polyols obtained by ring-opening polymerization of an alkylene oxide.

[0047] More specifically, examples of the polyether polyol include ethylene glycol, diethylene glycol, 1,2-propanediol (propylene glycol), 2-methyl-1,3-propanediol, 1,3-propanediol, 1,4-butanediol (tetramethylene glycol), 1,3-butanediol, 2,3-butanediol, 1,5-pentanediol, 2-methyl-1,5-pentanediol, 3-methyl-1,5-pentanediol, 2,3,5-trimethyl-1,5-pentanediol, 1,6-hexanediol, 2-ethyl-1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, 2,6-hexanediol, 1,8-octanediol, 1,4-cyclohexanedimethanol, 1,2-dimethylolcyclohexane, 1,3-dimethyl- Examples of the polyols include polymers of polyols such as ethylolcyclohexane, 1,4-dimethylolcyclohexane, 1,12-dodecanediol, polybutadiene diol, neopentyl glycol, dipropylene glycol, glycerin, trimethylolpropane, 1,3-dihydroxyacetone, hexylene glycol, 1,2,6-hexanetriol, ditrimethylolpropane, mannitol, sorbitol, and pentaerythritol; adducts of the above polyols with alkylene oxides such as ethylene oxide, propylene oxide, 1,2-butylene oxide, 1,3-butylene oxide, 2,3-butylene oxide, tetrahydrofuran, and epichlorohydrin; and ring-opening polymers of cyclic ethers such as tetrahydrofurans (for example, polytetramethylene glycol).

[0048] The number average molecular weight of the polyol compound (C) is not particularly limited, but is preferably in the range of 200 to 100,000, more preferably 500 to 50,000, even more preferably 1,000 to 10,000, and even more preferably 2,000 to 7,000. A number average molecular weight of 200 or more, preferably 500 or more, more preferably 1,000 or more, and even more preferably 2,000 or more improves the flexibility of the easy-adhesion layer and improves the crack resistance of the easy-adhesion layer during processing. On the other hand, a number average molecular weight of 100,000 or less, preferably 50,000 or less, more preferably 10,000 or less, and even more preferably 7,000 or less improves the effect of suppressing precipitation of the polyol compound in the easy-adhesion layer composition and the solubility of the polyol compound in other components. The number average molecular weight of the polyol compound (C) means a number average molecular weight calculated as standard polystyrene, measured by gel permeation chromatography (GPC).

[0049] The weight-average molecular weight of the polyol compound (C) is not particularly limited, but is preferably in the range of 200 to 300,000, more preferably in the range of 1,000 to 100,000, and even more preferably in the range of 10,000 to 40,000. A weight-average molecular weight of 200 or more, preferably 1,000 or more, and even more preferably 10,000 or more, improves the flexibility of the adhesion layer and the crack resistance of the adhesion layer during processing. On the other hand, a weight-average molecular weight of 300,000 or less, preferably 100,000 or less, and even more preferably 40,000 or less, improves the effect of suppressing precipitation of the polyol compound in the adhesion layer composition and the solubility of the polyol compound in other components. The weight-average molecular weight of the polyol compound (C) refers to the weight-average molecular weight in terms of standard polystyrene as measured by gel permeation chromatography (GPC).

[0050] The polyol compound (C) preferably has a hydroxyl value in the range of 10 to 200 KOH mg / g, more preferably in the range of 15 to 100 KOH mg / g, even more preferably in the range of 35 to 85 KOH mg / g, and even more preferably in the range of 50 to 70 KOH mg / g. By having a hydroxyl value of 10 KOH mg / g or more, preferably 15 KOH mg / g or more, even more preferably 35 KOH mg / g or more, and even more preferably 50 KOH mg / g or more, hydroxyl groups remain even after reaction with the acid anhydride (B) in the adhesion layer composition, so that hydroxyl groups that contribute to adhesion with the silicone-based pressure-sensitive adhesive layer can be effectively secured, and adhesion between the adhesion layer and the silicone-based pressure-sensitive adhesive layer can be improved. On the other hand, by ensuring that the hydroxyl value is 200 KOHmg / g or less, preferably 100 KOHmg / g or less, more preferably 85 KOHmg / g or less, and even more preferably 70 KOHmg / g or less, the reaction between the reactive functional groups that contribute to crosslinking of the silicone-based pressure-sensitive adhesive layer and the hydroxyl groups of the polyol compound can be made moderate, and the crosslinking properties of the silicone-based pressure-sensitive adhesive layer can be improved. As a result, sufficient crosslinking of the silicone pressure-sensitive adhesive layer improves the cohesive force and the adhesive transfer suppression effect can be improved.

[0051] As the polyol compound (C), an inorganic silicate hydrolyzate can be used. The silicate hydrolyzate has a large number of hydroxyl groups (silanol groups) and alkoxy groups, and the silanol groups undergo a curing reaction with the acid anhydride (B) during the formation of the adhesive layer coating. In addition, most of the alkoxy groups in the silicate hydrolyzate are dealcoholized during the formation of the adhesive layer coating to become hydroxyl groups (silanol groups), which then self-condense to form a silicate polymer structure, thereby further improving heat resistance. Furthermore, the hydroxyl groups (silanol groups) on the surface of the silicate polymer structure of the silicate hydrolyzate also react with reactive functional groups such as silanol groups and hydrosilyl groups contained in the silicone-based pressure-sensitive adhesive components, contributing to the adhesion between the adhesive layer and the silicone-based pressure-sensitive adhesive layer.

[0052] The silicate hydrolyzate can be obtained by hydrolyzing and condensing an alkyl silicate in an organic solvent such as an alcohol solvent in the presence of a specific amount of water and a condensation catalyst (acid or base). Examples of raw materials that can be used to form the silicate hydrolyzate include methyltrimethoxysilane, methyltriethoxysilane, tetramethoxysilane, and tetraethoxysilane. Additionally, silicate oligomers such as a tetramer of tetramethoxysilane and a pentamer of tetraethoxysilane can also be used.

[0053] As the silicate hydrolysate, a silicate hydrolysate liquid containing a commercially available silicate hydrolysate may be used as appropriate.

[0054] From the viewpoint of ensuring adhesion between the substrate and the silicone-based pressure-sensitive adhesive, the amount of the polyol compound (C) in the easy-adhesion layer composition is such that the mass ratio of the total mass of the epoxy compound (A) and the acid anhydride (B) to the polyol compound (C) {[(A) + (B)]:(C)} is preferably in the range of 10:90 to 90:10, more preferably in the range of 30:70 to 90:10, even more preferably in the range of 40:60 to 90:10, and still more preferably in the range of 45:55 to 90:10. By making the total blending amount of epoxy compound (A) and acid anhydride (B) 10:90 or more, preferably 30:70 or more, more preferably 40:60 or more, and even more preferably 45:55 or more, the adhesion between the substrate and the easy-adhesion layer is improved, and by making the total blending amount of epoxy compound (A) and acid anhydride (B) 90:10 or less, the blending amount of polyol compound (C) is effectively ensured, the adhesion between the easy-adhesion layer and the silicone pressure-sensitive adhesive layer is improved, and the effect of suppressing adhesive transfer to the adherend after the high-temperature heat treatment process is improved. Note that when silicate hydrolyzate is used as component (C), it becomes a silicate polymer structure (SiO2) when the easy-adhesion layer is formed, so the mass ratio is calculated by taking the amount of SiO2 in the silicate hydrolyzate as the mass of polyol compound (C).

[0055] The adhesive layer of the present invention may contain various additives such as antioxidants, antistatic agents, leveling agents, and antifoaming agents, as long as the effects of the present invention are obtained. The types and amounts of these additives may be appropriately selected within the range in which the effects of the present invention are obtained.

[0056] The thickness of the adhesive layer of the present invention is preferably in the range of 0.05 to 3.00 μm, more preferably 0.1 to 3.00 μm, and even more preferably 0.15 to 3.00 μm, from the viewpoints of adhesion to the substrate and the silicone-based pressure-sensitive adhesive and flexibility of the adhesive layer. By making the thickness of the adhesive layer 0.05 μm or more, preferably 0.1 μm or more, and even more preferably 0.15 μm or more, the adhesion is improved and the effect of suppressing adhesive transfer to the adherend after a high-temperature heat treatment step is improved. On the other hand, by making the thickness of the adhesive layer 3.00 μm or less, the cured film of the adhesive layer is provided with preferable flexibility, improving the film's bending followability and improving the crack suppression of the adhesive layer, thereby improving the effect of suppressing adhesive transfer to the adherend after a high-temperature heat treatment step.

[0057] (Adhesive Layer) The adhesive layer constituting the heat-resistant adhesive film of the present invention particularly uses a silicone-based adhesive because of its excellent heat resistance. As the silicone-based adhesive, silicone rubber (D unit [(CH3)2SiO 2 / 2 ]) and MQ resin (M unit [RSiO 1 / 2 where R is a monovalent organic group such as a methyl group or a phenyl group) and a Q unit [SiO 4 / 2 Examples of adhesives include those containing silicone rubber and MQ resin (a three-dimensional silicone resin polymer having a structure consisting of [a] and [b]). Adhesives containing such silicone rubber and MQ resin have superior adhesive properties compared to silicone rubber alone. Furthermore, basic adhesive properties such as adhesive strength, holding power, and tack can be controlled by changing the molecular weight and crosslink density of the silicone rubber and the ratio of MQ resin in the adhesive.

[0058] Silicone-based adhesives include addition-curing silicone adhesives, peroxide-curing silicone adhesives, and condensation-reaction-curing silicone adhesives depending on their curing mechanism. Addition-curing silicone adhesives are preferred because they can be cured and crosslinked at relatively low temperatures and can suppress the generation of by-products during curing.

[0059] The addition-curable silicone pressure-sensitive adhesive is preferably obtained by curing, through an addition reaction, a silicone composition containing a diorganopolysiloxane having two or more alkenyl groups per molecule and an organohydrogenpolysiloxane as a crosslinker. The silicone composition is uniformly applied and thermally cured to crosslink the silicone composition, thereby obtaining a suitable pressure-sensitive adhesive layer.

[0060] Examples of the diorganopolysiloxane having two or more alkenyl groups per molecule of the silicone composition include linear polydiorganosiloxanes having vinyl groups only at both ends, linear polyorganosiloxanes having vinyl groups at both ends and in the side chain, branched polyorganosiloxanes having vinyl groups only at the ends, and branched polyorganosiloxanes having vinyl groups at the ends and in the side chain.

[0061] The weight-average molecular weight of the diorganopolysiloxane having two or more alkenyl groups per molecule of the silicone composition is preferably in the range of 20,000 to 700,000, more preferably 50,000 to 400,000, and even more preferably 70,000 to 100,000. By having the weight-average molecular weight of the diorganopolysiloxane be 20,000 or more, preferably 50,000 or more, and even more preferably 70,000 or more, the curability is improved, and the crosslinking density is favorable, resulting in improved adhesion to the adherend. Furthermore, by having the weight-average molecular weight of the diorganopolysiloxane be 700,000 or less, preferably 400,000 or less, and even more preferably 100,000 or less, the viscosity of the silicone composition is favorable, resulting in improved manufacturability. The weight-average molecular weight refers to the weight-average molecular weight in terms of standard polystyrene measured by gel permeation chromatography (GPC).

[0062] The crosslinking agent for the silicone composition can be a known one. The organohydrogenpolysiloxane used as the crosslinking agent has at least three hydrogen atoms bonded to silicon atoms per molecule, and the molecular shape can be linear, branched, or cyclic. The hydrosilyl (SiH) groups contained in the organohydrogenpolysiloxane undergo an addition reaction with the alkenyl groups of the alkenyl-containing diorganopolysiloxane of the silicone composition, and simultaneously react with the hydroxyl groups contained in the adhesive layer of the present invention, thereby achieving strong adhesion between the adhesive layer and the silicone-based pressure-sensitive adhesive layer.

[0063] The molar ratio of SiH groups in the organohydrogenpolysiloxane to the alkenyl groups in the alkenyl group-containing diorganopolysiloxane of the silicone composition (SiH groups / alkenyl groups) is, for example, in the range of 0.5 to 3.0, more preferably 1.0 to 2.0, even more preferably 1.0 to 1.5, and even more preferably 1.1 to 1.4. A molar ratio (SiH groups / alkenyl groups) of 0.5 or more, preferably 1.0 or more, and even more preferably 1.1 or more improves the crosslink density of the silicone composition, increasing cohesive force and improving the adhesive transfer suppression effect, and also improves adhesion due to the reaction between the hydroxyl groups and SiH groups in the easy-adhesion layer. On the other hand, by ensuring that the molar ratio (SiH groups / alkenyl groups) is 3.0 or less, preferably 2.0 or less, more preferably 1.5 or less, and even more preferably 1.4 or less, the amount of unreacted hydrosilyl groups remaining in the cured product is reduced, and the cured product is better able to suppress changes in physical properties over time and decreases in heat resistance, and further is better able to suppress foaming due to a dehydrogenation reaction in the cured product.

[0064] The silicone composition contains an M unit (RSiO 1 / 2 where R is a monovalent organic group such as a methyl group or a phenyl group), and D units (RSiO 2 / 2 ), T units (RSiO 3 / 2 ), Q units (SiO 4 / 2However, it is preferable to use a conventionally known MQ resin consisting of M units and Q units, as this has a significant effect of improving the adhesive strength of the adhesive layer. The amount of MQ resin to be blended is determined appropriately depending on the required adhesive strength.

[0065] The platinum catalyst used in the crosslinking reaction of the silicone composition may be any known catalyst, and examples thereof include chloroplatinic acids such as chloroplatinic acid and chloroplatinic acid, alcohol compounds of chloroplatinic acid, aldehyde compounds, and chain salts of chloroplatinic acid with various olefins.

[0066] The silicone composition of the silicone-based pressure-sensitive adhesive layer of the present invention may contain additives, such as organic or inorganic particles, colorants, silicone oils, silicone resins, silane coupling agents, and antioxidants, to improve other properties.

[0067] The thickness of the silicone-based pressure-sensitive adhesive layer of the present invention is at least 5 μm or more, and typically 10 to 100 μm, to ensure adhesive strength and holding power to the adherend. A pressure-sensitive adhesive layer thickness of 5 μm or more improves the holding power in the shear direction with respect to adhesive strength to the adherend, improving adhesion to the adherend. Furthermore, a pressure-sensitive adhesive layer thickness of 100 μm or less reduces the amount of silicone composition used to form the pressure-sensitive adhesive layer, thereby reducing production costs.

[0068] The method for forming the silicone-based pressure-sensitive adhesive layer of the present invention involves uniformly applying the silicone composition, either as is or as a coating liquid with the viscosity adjusted using a solvent or the like, to the easy-adhesion layer of the present invention formed on a substrate to a predetermined thickness, followed by solvent drying and further heating to crosslink the silicone composition, thereby forming the silicone-based pressure-sensitive adhesive layer.

[0069] Examples of methods for applying the coating liquid for the adhesive layer and silicone-based pressure-sensitive adhesive layer of the present invention include gravure coaters, bar coaters, comma knife coaters, die coaters, and reverse coaters.

[0070] (Separator) In the present invention, it is preferable to use a separator made of a plastic film attached to the surface of the silicone-based pressure-sensitive adhesive layer in order to prevent contamination or adhesion of foreign matter to the surface of the silicone-based pressure-sensitive adhesive layer and to improve the handleability of the pressure-sensitive adhesive film. The separator is made of a plastic film with high releasability, and if desired, a release agent may be formed on the surface of the plastic film.

[0071] The heat-resistant adhesive film of the present invention will be described in detail below with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0072] <Preparation of Easy-Adhesion Layer Coating Liquid> The following cycloalkene oxide-type alicyclic epoxy compound (A-i), acid anhydride (B), and polyol compound (C) were used as easy-adhesion layer coating liquid materials to prepare easy-adhesion layer coating liquids for Examples 1-1 to 1-19, Comparative Examples 1-1 to 1-3, Examples 2-1 to 2-19, and Comparative Examples 2-1 to 2-3. The materials used and blending amounts for each easy-adhesion layer coating liquid are shown in Tables 1 to 8. The easy-adhesion layer coating liquid materials and solvent were mixed in the blending amounts shown in Tables 1 to 8 to prepare easy-adhesion layer coating liquids.

[0073] [Epoxy Compound (A)] [Cycloalkene Oxide-Type Alicyclic Epoxy Compound (A-i)] A-i-1: CELLOXIDE 2021P (3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexylcarboxylate, non-volatile content 100%, epoxy equivalent 130.5 g / eq) manufactured by Daicel Corporation, A-i-2: EPOCALIC THI-DE (tetrahydroindene diepoxide, non-volatile content 100%, epoxy equivalent 80 g / eq) manufactured by ENEOS Corporation, A-i-3: KBM-303 (2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, non-volatile content 100%, epoxy equivalent 246.4 g / eq) manufactured by Shin-Etsu Chemical Co., Ltd.

[0074] [Glycidylamine-Type Epoxy Compounds (A-ii)] A-ii-1: TETRAD-C (1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, non-volatile content 100%, epoxy equivalent 102.5 g / eq) manufactured by Mitsubishi Chemical Corporation; A-ii-2: jER630 (N,N-diglycidyl-4-(glycidyloxy)aniline, non-volatile content 100%, epoxy equivalent 98 g / eq) manufactured by Mitsubishi Chemical Corporation; A-ii-3: GAN (N,N-diglycidylaniline, non-volatile content 100%, epoxy equivalent 125 g / eq) manufactured by Nippon Kayaku Co., Ltd.

[0075] [Epoxy Compounds for Comparative Examples] A-4: As a comparative example, a bisphenol-type epoxy compound, jER828 (non-volatile content 100%, epoxy equivalent weight 189 g / eq) manufactured by Mitsubishi Chemical Corporation, which is neither a cycloalkene oxide-type alicyclic epoxy compound nor a glycidylamine-type epoxy compound.

[0076] [Acid Anhydrides (B)] B-1: Rikacid MH-700 manufactured by New Japan Chemical Co., Ltd. (a mixture containing cyclohexane-1,2-dicarboxylic anhydride and 4-methylcyclohexane-1,2-dicarboxylic anhydride, non-volatile content 100%, acid anhydride equivalent 163.5 g / eq), B-2: X-12-967C manufactured by Shin-Etsu Chemical Co., Ltd. (3-trimethoxysilylpropylsuccinic anhydride, non-volatile content 100%, acid anhydride equivalent 131.05 g / eq).

[0077] [Polyol Compounds (C)] C-1: HAS-1 (SiO concentration 21%, ethyl silicate hydrolyzate) manufactured by Colcoat Co., Ltd. C-2: Acridic A-817 (non-volatile content 50%, acrylic polyol, styrene-acrylic copolymer, hydroxyl value 60 mg KOH / g, glass transition temperature 95°C, weight average molecular weight 20,000) manufactured by DIC Corporation C-3: Vylon GK-810 (non-volatile content 100%, polyester polyol, hydroxyl value 19 mg KOH / g, glass transition temperature 46°C, number average molecular weight 4,600) manufactured by Toyobo Co., Ltd.

[0078] <Mass Ratio of Easy-Adhesion Layer Components> The total mass [(A) + (B)] of the epoxy compound (A) and the acid anhydride (B) and the mass of the polyol compound (C) in the easy-adhesion layer components of Examples 1-1 to 1-19, Comparative Examples 1-1 to 1-3, Examples 2-1 to 2-19, and Comparative Examples 2-1 to 2-3 were converted using the following calculation formulas 1 and 2, and the mass ratios {[(A) + (B)]:(C)} are shown in Tables 1 to 8, respectively. (Calculation Formula 1) {Total mass of epoxy compound (A) and acid anhydride (B) [(A) + (B)]} = [parts by mass of (A) + parts by mass of (B)] ÷ [parts by mass of (A) + parts by mass of (B) + parts by mass of (C) (non-volatile content)] × 100 (Calculation Formula 2) [Mass of polyol compound (C)] = [parts by mass of (C) (non-volatile content)] ÷ [parts by mass of (A) + parts by mass of (B) + parts by mass of (C) (non-volatile content)] × 100

[0079] <Mole Ratio of Easy-Adhesion Layer Components> The number of moles of the epoxy groups of the epoxy compound (A) and the acid groups of the acid anhydride (B) in the easy-adhesion layer components of Examples 1-1 to 1-19, Comparative Examples 1-1 to 1-3, Examples 2-1 to 2-19, and Comparative Examples 2-1 to 2-3 was calculated using the following calculation formulas 3 and 4, and the molar ratios {[epoxy groups of (A)]:[acid groups of (B)]} are shown in Tables 1 to 4, respectively. (Calculation Formula 3) [Number of moles of epoxy groups in epoxy compound (A)] = [parts by mass of (A) ÷ epoxy equivalent of (A)] ÷ [parts by mass of (A) ÷ epoxy equivalent of (A) + parts by mass of (B) ÷ acid anhydride equivalent of (B)] × 100 (Calculation Formula 4) [Number of moles of acid groups in acid anhydride (B)] = [parts by mass of (B) ÷ acid anhydride equivalent of (B)] ÷ [parts by mass of (A) ÷ epoxy equivalent of (A) + parts by mass of (B) ÷ acid anhydride equivalent of (B)] × 100

[0080] <Preparation of Easy-Adhesion Layer-Coated Substrate> Each of the coating liquids of Examples 1-1 to 1-19, Comparative Examples 1-1 to 1-3, Examples 2-1 to 2-19, and Comparative Examples 2-1 to 2-3 was applied using a Meyer bar onto each of the substrate films listed in Tables 1 to 8 so that the easy-adhesion layer thickness after solvent drying would be the thickness listed in Tables 1 to 4. The substrates onto which each easy-adhesion layer coating liquid had been coated were immediately heated in a gear oven at 120°C for 1 minute to dry the solvent and heat-cure, thereby obtaining easy-adhesion layer-coated substrates.

[0081] <Evaluation of Curability of Easy-Adhesion Layer> The surface of the easy-adhesion layer of each of the easy-adhesion layer-coated substrates of Examples 1-1 to 1-19, Comparative Examples 1-1 to 1-3, Examples 2-1 to 2-19, and Comparative Examples 2-1 to 2-3 was rubbed with a finger five times, and the surface condition and transfer of the easy-adhesion layer components to the finger were visually confirmed and evaluated according to the following criteria. The evaluation results are shown in Tables 1 to 8. ○: No change in the coating surface, and no transferred components on the finger surface △: Some whitening on the coating surface, but no transferred components on the finger surface ×: Whitening on the coating surface, and transferred components on the finger surface In Comparative Examples 1-3 and 2-3, the curability of the easy-adhesion layer was evaluated as "×", and further evaluation was not possible.

[0082] <Evaluation of Adhesion Between Substrate and Easy-Adhesion Layer> The surface of the easy-adhesion layer of each of the easy-adhesion layer-coated substrates of Examples 1-1 to 1-19, Comparative Examples 1-1 and 1-2, Examples 2-1 to 2-19, and Comparative Examples 2-1 and 2-2 was rubbed with a finger, and the adhesion between the substrate and the easy-adhesion layer was visually observed and evaluated according to the following criteria. The evaluation results are shown in Tables 1 to 8. ⊚: No peeling from the substrate after 50 finger rubs ◯: Peeling from the substrate after 10 or more but less than 50 finger rubs ×: Peeling from the substrate after less than 10 finger rubs

[0083] <Preparation of Adhesive Films> Adhesive layer coating liquids 1 to 3 were prepared by mixing the materials in the blending amounts shown in Table 9. The adhesive layer coating liquids shown in Tables 1 to 8 were applied with an applicator to the surface of each of the adhesive layer-coated substrates of Examples 1-1 to 1-19, Comparative Examples 1-1 and 1-2, Examples 2-1 to 2-19, and Comparative Examples 2-1 and 2-2, on which the easy-adhesion layer had been formed, so that the adhesive layer thickness after solvent drying was 10 μm. The substrates onto which each adhesive layer coating liquid had been laminated were immediately heated in a gear oven at 150°C for 1 minute to dry the solvent and heat-cure, thereby producing the respective adhesive films.

[0084] <Evaluation of Adhesion Between Easy-Adhesion Layer and Pressure-Sensitive Adhesive Layer> A 50 mm square sample was cut out from each of the pressure-sensitive adhesive films prepared in Examples 1-1 to 1-19, Comparative Examples 1-1 and 1-2, Examples 2-1 to 2-19, and Comparative Examples 2-1 and 2-2, and the cut edge of the pressure-sensitive adhesive layer of the cut-out sample was rubbed with a finger to visually observe the adhesion between the easy-adhesion layer and the pressure-sensitive adhesive layer, and evaluated according to the following criteria. The evaluation results are shown in Tables 1 to 8. ⊚: No detachment from the substrate after 15 finger rubs ◯: Detachment from the substrate after 5 or more but less than 15 finger rubs ×: Detachment from the substrate after less than 5 finger rubs

[0085] <Preparation of rolled copper foil adhesive samples> A sample measuring 25 mm wide and 120 mm long was cut out from each of the adhesive films prepared in Examples 1-1 to 1-19, Comparative Examples 1-1 and 1-2, Examples 2-1 to 2-19, and Comparative Examples 2-1 and 2-2. The adhesive layer surface of the cut-out sample was attached to a rolled copper foil measuring 50 mm wide, 150 mm long, and 50 μm thick, and left at room temperature for 20 to 40 minutes to prepare a rolled copper foil adhesive sample for evaluation. A total of six adhesive samples were prepared using each adhesive film: one for flexibility evaluation and five for heat resistance adhesive transfer evaluation.

[0086] <Flexibility Evaluation> When the pressure-sensitive adhesive films of the rolled copper foil-attached samples of Examples 1-1 to 1-19, Comparative Examples 1-1 and 1-2, Examples 2-1 to 2-19, and Comparative Examples 2-1 and 2-2 prepared above were peeled from the rolled copper foil in a 180-degree direction at room temperature at a speed of 300 mm / min, the occurrence of cracks in the easy-adhesion layer of each pressure-sensitive adhesive film was visually confirmed and evaluated according to the following criteria. The evaluation results are shown in Tables 1 to 8. ○: No cracks occurred in the easy-adhesion layer during peeling, and peeling was easy. △: Partial cracks occurred in the easy-adhesion layer during peeling. ×: Cracks occurred over the entire surface of the easy-adhesion layer during peeling.

[0087] <Heat Resistance and Adhesive Residue Evaluation> Five rolled copper foil samples from each of Examples 1-1 to 1-19, Comparative Examples 1-1 and 1-2, Examples 2-1 to 2-19, and Comparative Examples 2-1 and 2-2 prepared above were placed in a 175°C Geer oven and subjected to heat treatment. One of each of the five rolled copper foil samples was removed after 2, 4, 6, 8, and 10 minutes had elapsed and allowed to cool at room temperature for at least 5 minutes. The adhesive film from each heat-treated and cooled rolled copper foil sample was peeled from the rolled copper foil in a 180° direction at room temperature at a rate of 300 mm / min. The adhesive film was visually inspected for adhesive residue on the rolled copper foil surface after peeling, and evaluated according to the following criteria. The evaluation results are shown in Tables 1 to 8. ◎: No adhesive residue occurs after heat treatment at 175°C for 10 minutes. ○: Adhesive residue occurs after heat treatment at 175°C for 4 to 10 minutes. ×: Adhesive residue occurs after heat treatment at 175°C for 2 minutes.

[0088] <Confirmation of adhesive strength before and after heat treatment> From the adhesive films of Examples 1-1 to 1-3 and Examples 2-1 to 2-3 (representative samples of adhesive layer coating solutions 1 to 3) prepared above, samples with a width of 25 mm and a length of 250 mm were cut out, and the adhesive layer surface of the cut-out sample was attached to a rolled copper foil with a width of 50 mm, a length of 120 mm, and a thickness of 50 μm, and then pressed with a 2 kg roller to prepare an adhesive sample. Two adhesive samples were prepared for each sample, one of which was left at 23 ° C. and 50% RH for 30 minutes (before heat treatment), and the other was left at 23 ° C. and 50% RH for 30 minutes, then placed in a gear oven at 175 ° C. for 10 minutes to undergo heat treatment, and then further left at 23 ° C. and 50% RH for 5 minutes (after heat treatment), and these were used as adhesive strength measurement samples.

[0089] For the adhesive strength measurement sample, in accordance with JIS Z0237:2009, the force when peeling the adhesive film from the rolled copper foil at a peel angle of 180 degrees and a peel rate of 300 mm / min was measured using a tensile tester under an environment of 23 ° C. and 50% RH, and this was taken as the adhesive strength (N / 25 mm). The measurement results are shown in Tables 1 and 5.

[0090]

[0091]

[0092]

[0093]

[0094]

[0095]

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[0097]

[0098]

[0099] 1: Adhesive film 2: Base material 3: Easy-adhesion layer 4: Silicone-based adhesive layer 5: Separator

Claims

1. An adhesive film having a base material and an easy-adhesion layer and a silicone-based adhesive layer laminated in this order on at least one surface of the base material, wherein the easy-adhesion layer is a cured product obtained by thermally curing a composition containing an epoxy compound (A) selected from the group consisting of a cycloalkene oxide type alicyclic epoxy compound (A-i) and a glycidylamine type epoxy compound (A-ii), an acid anhydride (B), and a polyol compound (C).

2. The adhesive film according to claim 1, wherein the polyol compound (C) is a silicate hydrolyzate.

3. The adhesive film according to claim 1, wherein the polyol compound (C) is an acrylic polyol.

4. In the composition containing an epoxy compound (A) selected from the group consisting of a cycloalkene oxide type alicyclic epoxy compound (A-i) and a glycidylamine type epoxy compound (A-ii), an acid anhydride (B), and a polyol compound (C) for forming the easy-adhesion layer, the mass ratio {[(A) + (B)]:(C)} of the total mass of the epoxy compound (A) and the acid anhydride (B) to the mass of the polyol compound (C) is 10:90 to 90:

10. The adhesive film according to claim 1, characterized by this.

5. In the composition containing an epoxy compound (A) selected from the group consisting of a cycloalkene oxide type alicyclic epoxy compound (A-i) and a glycidylamine type epoxy compound (A-ii), an acid anhydride (B), and a polyol compound (C) for forming the easy-adhesion layer, the molar ratio {[epoxy group of (A)]:[acid group of (B)]} of the epoxy group of the epoxy compound (A) to the acid group of the acid anhydride (B) is 20:80 to 80:

20. The adhesive film according to claim 1, characterized by this.

6. The adhesive film according to claim 1, wherein the film thickness of the easy-adhesion layer is 0.05 to 3.00 μm.

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