Adhesive film, adhesive film with release film, adhesive film for constituent member of flexible image display device, laminate for flexible image display device, and flexible image display device

Abstract

Provided is the following adhesive film excellent in heat resistance and capable of suppressing warpage of a laminate.　This adhesive film is formed from a resin composition containing (A) an epoxy resin having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, (B) a urethane resin, and (C) an epoxy resin curing agent, wherein the storage elastic modulus (E') at 100°C after curing is 1 × 107 Pa or less.

Description

Adhesive film, adhesive film with release film, adhesive film for component of flexible image display device, laminate for flexible image display device, and flexible image display device

[0001] The present invention relates to an adhesive film, an adhesive film with a release film, an adhesive film for a component of a flexible image display device, a laminate for a flexible image display device, and a flexible image display device.

[0002] In recent years, development of flexible image display devices has been progressing among image display devices equipped with liquid crystal displays, organic EL displays, etc., such as bendable displays with curved image display surfaces, foldable displays that can be repeatedly bent, and rollable displays that can be rolled up. Such image display devices have a laminated structure in which multiple component sheets, such as surface protection films, cover lenses, circular polarizers, touch film sensors, and light-emitting elements, are bonded together with adhesive layers, and each laminated structure can be considered as a laminated sheet formed by laminating component sheets and adhesive layers.

[0003] Patent Document 1 discloses a laminate including a double-sided pressure-sensitive adhesive sheet having a glass transition temperature and storage modulus within a predetermined range, which does not break or peel even in a bending test approximating an actual use environment, and a flexible member for an image display device. However, although the double-sided pressure-sensitive adhesive sheet disclosed in Patent Document 1 has high bending resistance, it has a low modulus and insufficient heat resistance. Furthermore, when a liquid adhesive is used as the adhesive layer, the adhesive must usually be cured by active energy rays or heat. When image display device components are laminated via a liquid adhesive and the adhesive is cured, the adhesive is likely to overflow or have thickness variations, and there are also problems with the laminate being significantly warped due to the adhesive shrinkage during cure.

[0004] International Publication No. 2018 / 173896

[0005] Therefore, in this context, the present invention provides an adhesive film that has excellent heat resistance and can suppress warping of the laminate, an adhesive film with a release film, an adhesive film for components of a flexible image display device, a laminate for an image display device, and a flexible image display device.

[0006] In view of the above circumstances, the present inventors have developed an adhesive film formed from a resin composition containing an epoxy resin (A) having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, a urethane resin (B), and an epoxy resin curing agent (C), wherein the storage modulus (E') at 100°C after curing is 1 x 10 7 The inventors have found that an adhesive film having a storage modulus (E') at 100°C after curing is excellent in both heat resistance and warpage resistance. The inventors have also found that an adhesive film formed from a resin composition containing an epoxy resin (A) having a number-average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, and a liquid epoxy compound (F) having a boiling point at 1 atmosphere of 170°C or more (excluding the epoxy resin (A)), is excellent in both heat resistance and warpage resistance when cured. The inventors have also found that an adhesive film formed from a resin composition containing an epoxy resin (A) having a number-average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, a urethane resin (B), an epoxy resin curing agent (C), and a liquid epoxy compound (d1) having an epoxy equivalent of 1,000 g / eq or less, and having a storage modulus (E') at 100°C after curing is excellent in both heat resistance and warpage resistance when cured. 7 It has been found that an adhesive film having a modulus of 100 Pa or less has excellent heat resistance and excellent resistance to warping when cured.

[0007] That is, the present invention has the following aspects: [1] An adhesive film formed from a resin composition containing an epoxy resin (A) having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, a urethane resin (B), and an epoxy resin curing agent (C), wherein the storage modulus (E') at 100°C after curing is 1 x 10 7Pa or less. [2] The adhesive film according to [1], wherein the loss tangent (Tan δ) at 50°C after curing is 0.1 or more. [3] The adhesive film according to [1] or [2], wherein the resin composition further contains an epoxy compound (D) having an epoxy equivalent of 1,000 g / eq or less. [4] The adhesive film according to [3], wherein the epoxy compound (D) contains a urethane-modified epoxy compound. [5] The adhesive film according to any one of [1] to [4], wherein the content of the urethane resin (B) in the resin composition is 10 to 85 mass%. [6] The adhesive film according to any one of [1] to [5], wherein the epoxy resin curing agent (C) contains an amine-based curing agent. [7] The adhesive film according to any one of [1] to [5], wherein the storage modulus (E') at 20°C of the urethane resin (B) is 1 x 10 7The adhesive film according to any one of [1] to [6], wherein the epoxy equivalent of the liquid epoxy compound (F) is 1,000 g / eq or less. [8] An adhesive film formed from a resin composition containing an epoxy resin (A) having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, and a liquid epoxy compound (F) having a boiling point at 1 atmosphere of 170°C or more (excluding the epoxy resin (A)). [9] The adhesive film according to [8], wherein the epoxy equivalent of the liquid epoxy compound (F) is 1,000 g / eq or less.

[10] The adhesive film according to [8] or [9], wherein the resin composition contains a solid epoxy compound (d2) having an epoxy equivalent of 1,000 g / eq or less.

[11] The adhesive film according to any one of [8] to

[10] , wherein the mass ratio [(A):(F)] of the epoxy resin (A) to the liquid epoxy compound (F) in the resin composition is 95:5 to 50:50.

[12] The adhesive film according to

[10] or

[11] , wherein the mass ratio [(A):(d2)] of the epoxy resin (A) to the solid epoxy compound (d2) in the resin composition is 99:1 to 50:50.

[13] The adhesive film according to any one of [8] to

[12] , wherein the resin composition contains an epoxy resin curing agent (C).

[14] The adhesive film according to

[13] , wherein the epoxy resin curing agent (C) contains an amine-based curing agent.

[15] An adhesive film formed from a resin composition containing an epoxy resin (A) having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, a urethane resin (B), an epoxy resin curing agent (C), and a liquid epoxy compound (d1) having an epoxy equivalent of 1,000 g / eq or less, wherein the adhesive film has a storage modulus (E') at 100°C after curing of 1 x 10 7an adhesive film having a viscosity of 100 Pa or less.

[16] The adhesive film according to

[15] , wherein the epoxy resin curing agent (C) contains an amine-based curing agent.

[17] The adhesive film according to any one of [1] to

[16] , wherein the resin composition has an epoxy equivalent of 400 to 50,000 g / eq.

[18] The adhesive film according to any one of [1] to

[17] , wherein, when differential scanning calorimetry (DSC) is performed at a heating rate of 10°C / min, the adhesive film has an exothermic peak in a temperature range of 120 to 220°C, and the heat quantity of the exothermic peak is 5 J / g or more.

[19] The adhesive film according to any one of [1] to

[18] , wherein the glass transition temperature (Tg1) determined by differential scanning calorimetry (DSC) at a heating rate of 10°C / min is 0 to 120°C, and the temperature (T1) of the exothermic peak in the differential scanning calorimetry (DSC) and the glass transition temperature (Tg1) satisfy the relationship of the following formula: T1-Tg1≧60

[20] The adhesive film according to any one of [1] to

[19] , having a solvent content of 10,000 ppm or less.

[21] The adhesive film according to any one of [1] to

[20] , having a total light transmittance of 80% or more and a haze of 5% or less.

[22] An adhesive film with a release film, having a configuration in which the adhesive film according to any one of [1] to

[21] and a release film are laminated together.

[23] An adhesive film for a component of a flexible image display device, comprising the adhesive film according to any one of [1] to

[21] .

[24] A laminate for a flexible image display device, having a configuration in which two components of an image display device are laminated together via the adhesive film according to any one of [1] to

[21] .

[25] The laminate for a flexible image display device according to

[24] , having a curved portion or a bendable portion.

[26] A flexible image display device, comprising the laminate for a flexible image display device according to

[24] or

[25] .

[0008] The adhesive film of the present invention has excellent heat resistance and excellent resistance to warping when cured, and therefore can be suitably used as an adhesive film for image display devices.

[0009] An example of an embodiment of the present invention will be described in detail below. However, the present invention is not limited to the embodiment described below. In the present invention, the term "film" conceptually includes a sheet, a film, and a tape. Furthermore, when the term "panel" is used, such as an image display panel or a protective panel, it includes a plate, a sheet, and a film.

[0010] In this specification, when it is stated that "x to y" (x and y are any numbers), it means "x or more and y or less" unless otherwise specified, and also includes the meaning of "preferably greater than x" or "preferably smaller than y." Furthermore, when it is stated that "x or more" (x is any number), it also includes the meaning of "preferably greater than x" unless otherwise specified, and when it is stated that "y or less" (y is any number), it also includes the meaning of "preferably smaller than y" unless otherwise specified. Furthermore, "x and / or y (x and y are any configurations)" means at least one of x and y, and can mean three possibilities: x only, y only, or x and y. In this specification, "main component" means a component that has a significant effect on the properties of the target object, and the content of the component is usually 50% by mass or more of the target object, preferably 55% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and may even be 100% by mass. In the present specification, when numerical ranges are described in stages, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of another numerical range. In addition, in the numerical ranges described in this specification, the upper or lower limit of the numerical range can also be replaced with the values ​​shown in the examples.

[0011] The adhesive film according to one embodiment of the present invention is a film in an A-stage or B-stage state. The A-stage state, as defined in JIS K6900:1994, refers to the initial stage in the preparation of thermosetting resins, in which the material is still soluble and fusible in certain liquids. The B-stage state, as defined in JIS K6900:1994, refers to an intermediate stage in which the material swells when in contact with certain liquids and softens when heated, but does not completely dissolve or melt. The adhesive film is usually applied to an adherend and heat-treated to fully cure (C-stage state) and exert adhesive strength to the adherend.

[0012] The adhesive film according to one embodiment of the present invention is formed from a resin composition containing an epoxy resin (A) having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, a urethane resin (B), and an epoxy resin curing agent (C), and has a storage modulus (E') at 100°C after curing of 1 x 10 7 Pa or less (hereinafter, this film may be referred to as "present film 1", and the resin composition forming this film 1 may be referred to as "resin composition 1").

[0013] In addition, an adhesive film according to another embodiment of the present invention is formed from a resin composition containing an epoxy resin (A) having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, and a liquid epoxy compound (F) (excluding the epoxy (A)) having a boiling point at 1 atmosphere of 170°C or more (hereinafter, this may be referred to as "film 2 of the present invention," and the resin composition forming film 2 may be referred to as "resin composition 2").

[0014] Furthermore, an adhesive film according to another embodiment of the present invention is formed from a resin composition containing an epoxy resin (A) having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, a urethane resin (B), an epoxy resin curing agent (C), and a liquid epoxy compound (d1) having an epoxy equivalent of 1,000 g / eq or less, and having a storage modulus (E') at 100°C after curing of 1 x 10 7Pa or less (hereinafter, this film may be referred to as "the present film 3", and the resin composition forming the present film 3 may be referred to as "resin composition 3").

[0015] The following describes the present films 1 to 3. In this specification, the present films 1 to 3 may be collectively referred to simply as "the present film," and the resin compositions 1 to 3 may be collectively referred to simply as "the resin composition."

[0016] <<Present Film 1 (Resin Composition 1)>> The resin composition 1 forming the present film 1 contains an epoxy resin (A) (hereinafter, sometimes referred to as “epoxy resin (A)”) having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, a urethane resin (B), and an epoxy resin curing agent (C).

[0017] [Epoxy Resin (A)] The epoxy resin (A) is preferably a thermosetting resin having an epoxy group, excluding the silane coupling agent (E) described below.

[0018] The number-average molecular weight of the epoxy resin (A) used in the present film 1 is 10,000 or more, preferably 15,000 or more, more preferably 20,000 or more, and particularly preferably 30,000 or more, from the viewpoints of excellent heat resistance and suppressing warping of the laminate. The upper limit is usually 200,000, preferably 150,000, more preferably 100,000, for example, usually 10,000 to 200,000, preferably 20,000 to 150,000, more preferably 20,000 to 100,000. In the present invention, the number-average molecular weight of the epoxy resin can be measured as a value converted into standard polystyrene by gel permeation chromatography (GPC).

[0019] In order to provide excellent heat resistance and suppress warpage of the laminate, the epoxy resin (A) has an epoxy equivalent of 5,000 g / eq or more, preferably 6,000 g / eq or more, more preferably 7,000 g / eq or more, and particularly preferably 7,500 g / eq or more, as measured in accordance with JIS K 7236. The upper limit is usually 100,000 g / eq, preferably 75,000 g / eq, more preferably 50,000 g / eq, and is, for example, usually 5,000 to 100,000 g / eq, preferably 6,000 to 75,000 g / eq, more preferably 7,000 to 50,000 g / eq.

[0020] Examples of the epoxy resin (A) include modified epoxy resins such as alcohol-type epoxy resins, bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol C-type epoxy resins, bisphenol S-type epoxy resins, naphthalene-type epoxy resins, biphenyl-type epoxy resins, triphenylmethane-type epoxy resins, dicyclopentadiene-type epoxy resins, glycidyl ester-type epoxy resins, glycidyl amine-type epoxy resins, aliphatic epoxy resins, alicyclic epoxy resins, heterocyclic epoxy resins, urethane-modified epoxy resins, rubber-modified epoxy resins, and chelate-modified epoxy resins. These may be used alone or in combination of two or more.

[0021] Among these, it is preferable to use an epoxy resin having at least one skeleton selected from the group consisting of a phenyl skeleton (phenol skeleton), a naphthalene skeleton, a fluorene skeleton, a biphenyl skeleton, an anthracene skeleton, a pyrene skeleton, a xanthene skeleton, an adamantane skeleton, and a dicyclopentadiene skeleton; from the viewpoint of heat resistance, it is more preferable to use an epoxy resin having at least one skeleton selected from the group consisting of a phenyl skeleton, a fluorene skeleton, and a biphenyl skeleton; and from the viewpoints of ease of production and heat resistance, it is even more preferable to use an epoxy resin having at least one skeleton selected from the group consisting of a bisphenol A skeleton, a bisphenol F skeleton, and a biphenyl skeleton.

[0022] The content of the epoxy resin (A) in the resin composition 1 is usually 5% by mass, preferably 10% by mass or more, more preferably 30% by mass or more, and particularly preferably 55% by mass or more. The upper limit is usually 95% by mass, preferably 90% by mass, and is usually 5 to 95% by mass, preferably 10 to 90% by mass.

[0023] [Urethane Resin (B)] The urethane resin (B) is a polymer having a urethane bond in the main chain. The urethane resin (B) may have a polyol-derived structural unit and a polyisocyanate-derived structural unit, and may further have a polycarboxylic acid-derived structural unit. The urethane resin (B) may be used alone or in combination of two or more types. The present film 1 is formed from a resin composition 1 containing a urethane resin (B) with a low elastic modulus, and therefore exhibits excellent warp resistance during curing.

[0024] Examples of the polyol include polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, and acrylic polyols. These compounds may be used alone or in combination.

[0025] Examples of the polyether polyols include polyethylene glycol, polypropylene glycol, polyethylene glycol-polypropylene glycol copolymer, polytetramethylene ether glycol, polyhexamethylene ether glycol, etc. Examples of the polyester polyols include polycarboxylic acids (malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, etc.) or their acid anhydrides and polyhydric alcohols (ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, etc.) diol, 2-methyl-2,4-pentanediol, 2-methyl-2-propyl-1,3-propanediol, 1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2,5-dimethyl-2,5-hexanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-butyl-2-hexyl-1,3-propanediol, cyclohexanediol, bishydroxymethylcyclohexane, benzenedimethanol, bishydroxyethoxybenzene, alkyldialkanolamine, lactonediol, etc. Examples of the polycarbonate polyols include polycarbonate diols obtained by dealcoholization reaction of the polyhydric alcohols with dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, etc., such as poly(1,6-hexylene) carbonate and poly(3-methyl-1,5-pentylene) carbonate. Among these, polyester polyols are preferred.

[0026] Examples of the polyisocyanate include aromatic diisocyanates such as tolylene diisocyanate, xylylene diisocyanate, methylene diphenyl diisocyanate, phenylene diisocyanate, naphthalene diisocyanate, and triazine diisocyanate; aliphatic diisocyanates having an aromatic ring such as α,α,α',α'-tetramethylxylylene diisocyanate; aliphatic diisocyanates such as methylene diisocyanate, propylene diisocyanate, lysine diisocyanate, trimethylhexamethylene diisocyanate, and hexamethylene diisocyanate; and alicyclic diisocyanates such as cyclohexane diisocyanate, methylcyclohexane diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and isopropylidenedicyclohexyl diisocyanate. These may be used alone or in combination.

[0027] In terms of warpage resistance, the urethane resin (B) has a storage modulus (E') at 20°C measured using a dynamic viscoelasticity measuring device of 1 x 10 7 Pa or less, and more preferably 8×10 6 Pa or less, particularly preferably 6 × 10 6 The lower limit is usually 1×10 4 Pa, preferably 1×10 5 Pa, for example, typically 1×10 4 ~1 x 10 7 Pa, preferably 1×10 5 ~8 x 10 6 It is Pa.

[0028] The storage modulus (E') can be determined by the following method. A solution of the urethane resin (B) diluted with an organic solvent is applied to a release film, heated at 120°C for 5 minutes, the organic solvent is dried, and the resulting cured film is cut into a 4 mm x 40 mm piece to serve as a measurement sample. This measurement sample is subjected to dynamic viscoelasticity measurement in accordance with JIS K7244-4:1999 using a viscoelasticity spectrometer "DVA-200 (manufactured by IT Measurement & Control Co., Ltd.)" in tension mode under conditions of a frequency of 1 Hz, a strain of 0.1%, a temperature range of -50 to 300°C, and a heating rate of 3°C / min, and the value of the storage tensile modulus (E') at 20°C is read.

[0029] From the viewpoint of warp resistance, the glass transition temperature (Tg) of the urethane resin (B) is preferably 0° C. or lower, more preferably −10° C. or lower, even more preferably −20° C. or lower, and particularly preferably −30° C. or lower. The lower limit is usually −80° C., preferably −70° C., and particularly preferably −60° C., and is, for example, usually −80 to 0° C., preferably −60 to −10° C., and more preferably −60 to −20° C.

[0030] The glass transition temperature (Tg) can be determined by reading the maximum value of the loss tangent (Tan δ) from the temperature dispersion spectrum of the dynamic viscoelasticity obtained by measuring the storage tensile modulus (E′).

[0031] The weight average molecular weight of the urethane resin (B) is not particularly limited, and is usually 5,000 to 500,000, preferably 10,000 to 200,000.

[0032] From the viewpoint of warp resistance, the content of the urethane resin (B) in the resin composition 1 is preferably 10 to 85% by mass, more preferably 15 to 70% by mass, even more preferably 18 to 65% by mass, particularly preferably 20 to 60% by mass, and especially preferably 25 to 55% by mass.

[0033] In addition, the mass ratio of the epoxy resin (A) to the urethane resin (B) in the resin composition 1 [(A):(B)] is preferably 95:5 to 10:90 from the viewpoint of warp resistance, more preferably 90:10 to 50:50, even more preferably 85:15 to 60:40, and particularly preferably 80:20 to 70:30.

[0034] [Epoxy Resin Curing Agent (C)] Examples of the epoxy resin curing agent (C) include polyfunctional phenol-based curing agents, amine-based curing agents, acid anhydride-based curing agents, imidazole-based curing agents, amide-based curing agents, cationic polymerization-based curing agents, and organic phosphine-based curing agents. These may be used alone or in combination of two or more. Among these, from the viewpoint of curability, amine-based curing agents and imidazole-based curing agents are preferred, and amine-based curing agents are particularly preferred.

[0035] Examples of the polyfunctional phenolic curing agent include bisphenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol AD, bisphenol Z, and tetrabromobisphenol A; biphenols such as 4,4'-biphenol and 3,3',5,5'-tetramethyl-4,4'-biphenol; catechol, resorcinol, hydroquinone, dihydroxynaphthalenes; and compounds in which the hydrogen atoms bonded to the aromatic rings of these compounds are substituted with non-interfering substituents such as halogen groups, alkyl groups, aryl groups, ether groups, ester groups, and organic substituents containing hetero elements such as sulfur, phosphorus, and silicon; and novolaks and resols which are polycondensates of the above-mentioned phenols or monofunctional phenols such as phenol, cresol, and alkylphenols with aldehydes.

[0036] Examples of the amine curing agent include aliphatic primary, secondary, and tertiary amines, aromatic primary, secondary, and tertiary amines, cyclic amines, guanidines, and urea derivatives. Specific examples include triethylenetetramine, polyoxypropylenediamine, diaminodiphenylmethane, diaminodiphenyl ether, metaxylenediamine, dicyandiamide, 1,8-diazabicyclo(5,4,0)-7-undecene, 1,5-diazabicyclo(4,3,0)-5-nonene, dimethylurea, and guanylurea. Among these, from the viewpoint of curability, aliphatic primary, secondary, and tertiary amines and cyclic amines are preferred, and polyoxypropylenediamine is more preferred.

[0037] Examples of the acid anhydride curing agent include phthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, and condensates of maleic anhydride and unsaturated compounds.

[0038] Examples of the imidazole curing agent include 1-isobutyl-2-methylimidazole, 2-methylimidazole, 1-benzyl-2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, benzimidazole, etc. Among these, 2-ethyl-4-methylimidazole is preferred.

[0039] Examples of the amide-based curing agent include dicyandiamide and its derivatives, polyamide resins, and the like.

[0040] The cationic polymerization curing agent generates cations when exposed to heat or active energy rays, and examples thereof include aromatic onium salts. - , BF4 - , AsF6 - , PF6 - , CF3SO3 - , B(C6F5)4 - and an aromatic cation component containing an atom such as iodine, sulfur, nitrogen, or phosphorus.

[0041] Examples of the organic phosphine curing agent include tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, phenylphosphine, etc.; phosphonium salts such as tetraphenylphosphonium tetraphenylborate, tetraphenylphosphonium ethyltriphenylborate, and tetrabutylphosphonium tetrabutylborate; and tetraphenylboron salts such as 2-ethyl-4-methylimidazole tetraphenylborate and N-methylmorpholine tetraphenylborate.

[0042] The content of the epoxy resin curing agent (C) is usually 0.001 to 20 parts by mass, preferably 0.01 to 10 parts by mass, and particularly preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the epoxy components (the total of the epoxy resin (A) and the epoxy compound (D) described below having an epoxy equivalent of 1,000 g / eq or less) contained in the resin composition 1.

[0043] [Epoxy compound (D) having an epoxy equivalent of 1,000 g / eq or less] From the viewpoint of heat resistance, the resin composition 1 forming the present film 1 preferably contains, in addition to the epoxy resin (A), an epoxy compound (D) having an epoxy equivalent of 1,000 g / eq or less (hereinafter, sometimes referred to as "epoxy compound (D)"). The epoxy compound (D) does not include the silane coupling agent (E) described below, i.e., an organosilicon compound containing, in its structure, one or more reactive functional groups and one or more alkoxy groups bonded to a silicon atom. The epoxy compound (D) can be used alone or in combination of two or more.

[0044] From the viewpoint of curability, the epoxy compound (D) preferably has an epoxy equivalent of 1,000 g / eq or less, more preferably 800 g / eq or less, particularly preferably 500 g / eq or less, and even more preferably 300 g / eq or less, as measured in accordance with JIS K7236. The lower limit is usually 50 g / eq, preferably 100 g / eq, and for example, usually 50 to 1,000 g / eq, preferably 100 to 800 g / eq. If the epoxy equivalent of the epoxy compound (D) exceeds 1,000 g / eq, the adhesive strength of the present film tends to decrease.

[0045] The epoxy compound (D) may be a liquid epoxy compound (d1) or a solid epoxy compound (d2). Liquid epoxy compound (d1) is preferred from the viewpoint of reducing the content of volatile substances contained in the present film, and solid epoxy compound (d2) is preferred from the viewpoint of heat resistance. In this specification, "liquid" refers to a state that is fluid at 25°C, specifically, a viscosity measured with a Brookfield viscometer of typically 1,000,000 mPa·s or less, preferably 100,000 mPa·s or less, more preferably 10,000 mPa·s or less, even more preferably 5,000 mPa·s or less, particularly preferably 1,000 mPa·s or less, and most preferably 100 mPa·s or less. In this specification, "solid" refers to a solid state at 25°C, specifically, a softening point of typically 30°C or higher, preferably 40°C or higher, more preferably 50°C or higher, and even more preferably 60°C or higher.

[0046] The liquid epoxy compound (d1) is a so-called reactive diluent, and by using this liquid epoxy compound (d1), volatile substances such as solvents can be efficiently removed during heating when forming the present film. Examples of the liquid epoxy compound (d1) include monofunctional aliphatic epoxy compounds such as ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, 1,2-epoxytetradecane, and lauryl glycidyl ether; monofunctional aromatic epoxy compounds such as o-phenylphenol glycidyl ether, phenyl glycidyl ether, 2-biphenylyl glycidyl ether, and 4-t-butylphenyl glycidyl ether; polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether; and 1,4-butane. Examples of the liquid epoxy compound (d1) include bifunctional aliphatic epoxy compounds such as diol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and dimer acid diglycidyl ester; bifunctional alicyclic epoxy compounds such as 1,4-cyclohexanedimethanol diglycidyl ether and hydrogenated bisphenol A diglycidyl ether; and bifunctional aromatic epoxy compounds such as cresyl glycidyl ether; trifunctional epoxy compounds such as trifunctional aliphatic epoxy compounds such as trimethylolpropane triglycidyl ether; and modified epoxy compounds such as urethane-modified epoxy compounds, rubber-modified epoxy compounds, and chelate-modified epoxy compounds. The liquid epoxy compound (d1) can be used alone or in combination of two or more. Among these, urethane-modified epoxy compounds are preferred in terms of heat resistance and warpage resistance.

[0047] Examples of the solid epoxy compound (d2) include bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, bisphenol C type epoxy compounds, bisphenol S type epoxy compounds, naphthalene type epoxy compounds, phenol novolac type epoxy compounds, cresol novolac type epoxy compounds, bisphenol A novolac type epoxy compounds, triphenylmethane type epoxy compounds, dicyclopentadiene type epoxy compounds, and polyfunctional phenol type epoxy compounds. These may be used alone or in combination of two or more. The solid epoxy compound (d2) may be used alone or in combination of two or more. Among them, bisphenol A novolac type epoxy compounds are preferred in terms of heat resistance.

[0048] Commercially available examples of the solid epoxy compound (d2) include, but are not limited to, jER154, jER157S70, jER157S65, jER1031S, jER1032H60, jER6810, jERYX7700, jERYX8800, jERYX7760, jERYX4000, jERYX4000H, jERYX4000HS, jERYL6121HA, and jERYL6677 (all trade names, manufactured by Mitsubishi Chemical Corporation).

[0049] The number average molecular weight of the epoxy compound (D) is usually 250 or more, preferably 300 or more, more preferably 350 or more, and particularly preferably 370 or more, from the viewpoint of excellent heat resistance and suppressing warpage of the laminate. The upper limit is usually 10,000, preferably 7,000, and more preferably 5,000, and is, for example, usually 250 to 10,000, preferably 300 to 7,000, and more preferably 350 to 5,000.

[0050] When the resin composition 1 contains the epoxy compound (D), the content thereof is usually 80% by mass or less, preferably 70% by mass or less, particularly preferably 60% by mass or less. The lower limit is usually 0.1% by mass, preferably 1% by mass, for example, usually 0.1 to 80% by mass, preferably 1 to 70% by mass.

[0051] When the resin composition 1 contains the liquid epoxy compound (d1), the content thereof is usually 80% by mass or less, preferably 70% by mass or less, particularly preferably 60% by mass or less. The lower limit is usually 0.1% by mass, preferably 1% by mass, for example, usually 0.1 to 80% by mass, preferably 1 to 70% by mass.

[0052] When the resin composition 1 contains the solid epoxy compound (d2), the content thereof is usually 30% by mass or less, preferably 20% by mass or less, particularly preferably 10% by mass or less. The lower limit is usually 0.1% by mass, preferably 1% by mass, for example, usually 0.1 to 30% by mass, preferably 1 to 20% by mass.

[0053] In addition, the mass ratio of the epoxy resin (A) to the epoxy compound (D) [(A):(D)] in the resin composition 1 is preferably 99:1 to 1:99 from the viewpoint of heat resistance, more preferably 98:2 to 5:95, and particularly preferably 97:3 to 10:90.

[0054] The mass ratio of the epoxy resin (A) to the liquid epoxy compound (d1) in the resin composition 1 [(A):(d1)] is preferably 80:20 to 1:99 from the viewpoint of heat resistance, more preferably 75:25 to 5:95, and particularly preferably 70:30 to 10:90.

[0055] The mass ratio of the epoxy resin (A) to the solid epoxy compound (d2) [(A):(d2)] in the resin composition 1 is preferably 99:1 to 50:50 from the viewpoint of heat resistance, more preferably 98:2 to 55:45, and particularly preferably 97:3 to 85:15.

[0056] <Silane Coupling Agent (E)> The resin composition 1 preferably contains a silane coupling agent (E). The silane coupling agent (E) is an organosilicon compound containing one or more reactive functional groups and one or more alkoxy groups bonded to a silicon atom in its structure. Examples of the reactive functional group include an epoxy group, a (meth)acryloyl group, a mercapto group, a hydroxyl group, a carboxyl group, an amino group, an amide group, and an isocyanate group. Among these, an epoxy group and a mercapto group are preferred in terms of durability balance.

[0057] The alkoxy group bonded to the silicon atom preferably contains an alkoxy group having 1 to 8 carbon atoms from the viewpoint of durability and storage stability, and is particularly preferably a methoxy group or an ethoxy group. The silane coupling agent may also have an organic substituent other than the reactive functional group and the alkoxy group bonded to the silicon atom, such as an alkyl group or a phenyl group.

[0058] Specific examples of the silane coupling agent (E) include monomeric epoxy group-containing silane coupling agents, which are silane compounds such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; and silane coupling agents in which a part of the silane compound is hydrolyzed and condensed, or in which the silane compound is polymerized with methyltriethoxysilane, ethyltriethoxysilane, and the like. oligomeric epoxy group-containing silane coupling agents which are silane compounds obtained by co-condensation of alkyl group-containing silane compounds such as silane, methyltrimethoxysilane, and ethyltrimethoxysilane; monomeric mercapto group-containing silane coupling agents which are silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, γ-mercaptopropyldimethoxymethylsilane, and 3-mercaptopropylmethyldimethoxysilane; and mercapto group-containing silane coupling agents which are silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, γ-mercaptopropyldimethoxymethylsilane, and mercapto group-containing silane coupling agents which are silane compounds obtained by hydrolysis and condensation polymerization of a part of the silane compounds or by coupling with the silane compounds. Oligomeric mercapto group-containing silane coupling agents, which are silane compounds obtained by co-condensation of alkyl group-containing silane compounds such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, and ethyltrimethoxysilane; (meth)acryloyl group-containing silanes such as 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane; Coupling agents: amino group-containing silane coupling agents such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, and N-phenyl-3-aminopropyltrimethoxysilane; isocyanate group-containing silane coupling agents such as 3-isocyanatepropyltriethoxysilane;Examples of the silane coupling agent (E) include vinyl group-containing silane coupling agents such as vinyltrimethoxysilane and vinyltriethoxysilane. The silane coupling agent (E) may be used alone or in combination of two or more. Among these, epoxy group-containing silane coupling agents and mercapto group-containing silane coupling agents are preferably used from the viewpoint of excellent durability, and epoxy group-containing silane coupling agents are particularly preferred.

[0059] When the resin composition 1 contains the silane coupling agent (E), the content thereof is usually 0.005 to 10 parts by mass, preferably 0.01 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the epoxy component (e.g., the total of the epoxy resin (A) and the epoxy compound (D)) contained in the resin composition 1. When the content of the silane coupling agent (E) is within the above range, durability tends to be improved.

[0060] [Other Components] The resin composition 1 may optionally contain other components, such as resins other than epoxy resins, sensitizers, crosslinking agents, UV absorbers, polymerization inhibitors, fillers, antioxidants, leveling agents, slip agents, fine particles, dispersants, organic peroxides, reducing agents, radical polymerizable compounds, plasticizers, antifoaming agents, polymerization initiators, and elastomers, within a range that does not impair the effects of the present invention (for example, typically 10% by mass or less, preferably 5% by mass or less, of the resin composition 1). These may be used alone or in combination of two or more. For example, blending an elastomer tends to adjust the flexibility and impact resistance of the present film 1 after curing. Furthermore, blending a polymerization initiator such as a thermal polymerization initiator (e.g., peroxide, azo compound) or a photopolymerization initiator tends to adjust the strength of the present film 1 after curing.

[0061] The resin composition 1 can be obtained by uniformly mixing the epoxy resin (A), the urethane resin (B), the epoxy resin curing agent (C), preferably the epoxy compound (D), and other components as required, in a conventional manner.

[0062] The types and skeletons of the epoxy resin (A) and the epoxy compound (D) contained in the resin composition 1 can be confirmed by, for example, NMR (nuclear magnetic resonance spectroscopy), IR (infrared spectroscopy), SEM (scanning electron microscope) analysis, ICP (inductively coupled plasma) atomic emission spectroscopy, TGA (thermogravimetric analysis), DSC (differential scanning calorimetry), various types of chromatography, and the like.

[0063] From the viewpoint of heat resistance and warpage resistance, the resin composition 1 preferably has an epoxy equivalent, as measured in accordance with JIS K7236, of 400 to 50,000 g / eq, more preferably 1,000 to 30,000 g / eq, and particularly preferably 2,000 to 20,000 g / eq.

[0064] <<Present Film 2 (Resin Composition 2)>> The resin composition 2 that forms the present film 2 contains an epoxy resin (A) and a liquid epoxy compound (F) having a boiling point of 170°C or higher at 1 atmosphere (excluding the epoxy resin (A)).

[0065] [Epoxy Resin (A)] Examples of the epoxy resin (A) include the epoxy resin (A) described in the resin composition 1, and the preferred type, physical properties, content, etc. are also the same as those described in the resin composition 1.

[0066] Liquid Epoxy Compound (F) Having a Boiling Point of 170°C or Higher at 1 Atm: Liquid epoxy compound (F) having a boiling point of 170°C or higher at 1 atm (hereinafter, sometimes referred to as "liquid epoxy compound (F)") is excluding the epoxy resin (A). The present film 2 is formed from a resin composition 2 containing the liquid epoxy compound (F), and therefore exhibits excellent heat resistance and warpage resistance upon curing. The liquid epoxy compound (F) does not include the silane coupling agent (E). The liquid epoxy compound (F) is a so-called reactive diluent. By including the liquid epoxy compound (F) in the resin composition 2 forming the present film 2, volatile substances such as solvents can be efficiently removed during heating to form the film, thereby reducing the content of volatile substances contained in the present film 2. Therefore, the present film 2 can suppress warpage upon curing by heat treatment.

[0067] The boiling point of the liquid epoxy compound (F) is 170°C or higher, preferably 175°C or higher, more preferably 180°C or higher, and particularly preferably 185°C or higher, from the viewpoint of heat resistance. The upper limit is not particularly limited, but is usually 250°C or lower, preferably 220°C or lower, for example, usually 170 to 250°C, preferably 175 to 220°C. In this specification, the boiling point is a value at 1 atmosphere. If the boiling point at 1 atmosphere cannot be measured, a converted boiling point converted to 1 atmosphere using a boiling point conversion chart can be used.

[0068] The number average molecular weight of the liquid epoxy compound (F) is usually 1,000 or less, more preferably 500 or less, and particularly preferably 300 or less, from the viewpoint of suppressing warpage of the laminate. The lower limit is usually 100, for example, usually 100 to 1,000.

[0069] In order to suppress warpage of the laminate, the liquid epoxy compound (F) preferably has an epoxy equivalent measured in accordance with JIS K 7236 of 1,000 g / eq or less, more preferably 600 g / eq or less, even more preferably 400 g / eq or less, and particularly preferably 200 g / eq or less. The lower limit is preferably 50 g / eq, more preferably 100 g / eq, for example, preferably 50 to 1,000 g / eq, more preferably 100 to 600 g / eq.

[0070] Examples of such liquid epoxy compounds (F) include monofunctional epoxy compounds such as monofunctional aliphatic epoxy compounds such as ethyl glycidyl ether, propyl glycidyl ether, butyl glycidyl ether, 2-ethylhexyl glycidyl ether, 1,2-epoxytetradecane, and lauryl glycidyl ether, and monofunctional aromatic epoxy compounds such as o-phenylphenol glycidyl ether, phenyl glycidyl ether, 2-biphenylyl glycidyl ether, and 4-t-butylphenyl glycidyl ether; bifunctional aliphatic epoxy compounds such as polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and dimer acid diglycidyl ester; bifunctional epoxy compounds such as 1,4-cyclohexanedimethanol diglycidyl ether and hydrogenated bisphenol A diglycidyl ether; and bifunctional aromatic epoxy compounds such as cresyl glycidyl ether. Examples of the epoxy compound include trifunctional epoxy compounds such as trifunctional aliphatic epoxy compounds such as trimethylolpropane triglycidyl ether. These may be used alone or in combination of two or more. Among these, from the viewpoint of warp resistance, monofunctional epoxy compounds are preferred, monofunctional aliphatic epoxy compounds are more preferred, and 2-ethylhexyl glycidyl ether is particularly preferred.

[0071] The content of the liquid epoxy compound (F) in the resin composition 2 is usually 1 to 80% by mass, preferably 5 to 60% by mass, and particularly preferably 10 to 40% by mass.

[0072] The mass ratio of the epoxy resin (A) to the liquid epoxy compound (F) in the resin composition 2 [(A):(F)] is preferably 95:5 to 50:50 from the viewpoint of warp resistance, more preferably 90:10 to 60:40, and particularly preferably 85:15 to 70:30.

[0073] [Solid Epoxy Compound (d2)] From the viewpoint of heat resistance, the resin composition 2 forming the present film 2 preferably contains, in addition to the epoxy resin (A) and the liquid epoxy compound (F), the solid epoxy compound (d2) described in the resin composition 1. The preferred types, physical properties, etc. of the solid epoxy compound (d2) are as described in the resin composition 1. As described above, the solid epoxy compound (d2) excludes the silane coupling agent (E).

[0074] When the resin composition 2 contains the solid epoxy compound (d2), the content thereof is usually 30% by mass or less, preferably 20% by mass or less, particularly preferably 10% by mass or less. The lower limit is usually 0.1% by mass, preferably 1% by mass, for example, usually 0.1 to 30% by mass, preferably 1 to 20% by mass.

[0075] In addition, the mass ratio of the epoxy resin (A) to the solid epoxy compound (d2) in the resin composition 2 [(A):(d2)] is preferably 99:1 to 50:50 from the viewpoint of warpage resistance, more preferably 97:3 to 70:30, and particularly preferably 95:5 to 80:20.

[0076] [Epoxy Resin Curing Agent (C)] The resin composition 2 preferably contains an epoxy resin curing agent (C). The preferred type, physical properties, etc. of the epoxy resin curing agent (C) are the same as those described for the resin composition 1.

[0077] When the epoxy resin curing agent (C) is used, the content thereof is usually 0.001 to 20 parts by mass, preferably 0.01 to 10 parts by mass, and particularly preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the epoxy components contained in the resin composition 2 [for example, the total of the epoxy resin (A), the liquid epoxy compound (F), and the epoxy compound (d2)].

[0078] [Silane Coupling Agent (E)] The resin composition 2 preferably contains a silane coupling agent (E). The preferred type, physical properties, content, etc. of the silane coupling agent (E) are the same as those described for the resin composition 1.

[0079] [Other Components] The resin composition 2 may optionally contain other components, such as resins other than epoxy resins, sensitizers, crosslinking agents, UV absorbers, polymerization inhibitors, fillers, antioxidants, leveling agents, slip agents, fine particles, dispersants, organic peroxides, reducing agents, radical polymerizable compounds, plasticizers, antifoaming agents, polymerization initiators, and elastomers, within a range that does not impair the effects of the present invention (for example, typically 10% by mass or less, preferably 5% by mass or less, of the resin composition 2). These may be used alone or in combination of two or more. For example, blending an elastomer tends to adjust the flexibility and impact resistance of the film when cured. Furthermore, blending a polymerization initiator such as a thermal polymerization initiator (e.g., peroxide, azo compound) or a photopolymerization initiator tends to adjust the strength of the film when cured.

[0080] The resin composition 2 can be obtained by uniformly mixing the epoxy resin (A), the liquid epoxy compound (F), preferably the solid epoxy compound (d2), the epoxy resin curing agent (C), and other components as required, in a conventional manner.

[0081] The types and skeletons of the epoxy resin (A), liquid epoxy compound (F), and solid epoxy compound (d2) contained in the resin composition 2 can be confirmed by, for example, NMR (nuclear magnetic resonance spectroscopy), IR (infrared spectroscopy), SEM (scanning electron microscope) analysis, ICP (inductively coupled plasma) atomic emission spectroscopy, TGA (thermogravimetric analysis), DSC (differential scanning calorimetry), various types of chromatography, and the like.

[0082] From the viewpoint of heat resistance and warpage resistance, the resin composition 2 preferably has an epoxy equivalent, as measured in accordance with JIS K7236, of 400 to 50,000, more preferably 500 to 10,000 g / eq, even more preferably 600 to 8,000 g / eq, and particularly preferably 800 to 6,000 g / eq.

[0083] <<Present Film 3 (Resin Composition 3)>> The resin composition 3 forming the present film 3 contains an epoxy resin (A), a urethane resin (B), an epoxy resin curing agent (C), and a liquid epoxy compound (d1). The present film 3 is formed from the resin composition 3 containing the urethane resin (B) with a low elastic modulus, and therefore exhibits excellent warpage resistance when cured by heat treatment. Furthermore, the present film 3 is formed from the resin composition 3 containing the liquid epoxy compound (d1), and therefore volatile substances such as solvents can be efficiently removed during heating when forming the film, thereby reducing the content of volatile substances contained in the present film 3. Therefore, the present film 3 exhibits excellent warpage resistance when cured by heat treatment.

[0084] [Epoxy Resin (A)] The epoxy resin (A) may be the epoxy resin (A) described in the resin composition 1, and the preferred types, physical properties, etc. are also the same as those described in the resin composition 1.

[0085] The content of the epoxy resin (A) in the resin composition 3 is usually 1% by mass, preferably 3% by mass or more, more preferably 5% by mass or more, and particularly preferably 7% by mass or more. The upper limit is usually 70% by mass, preferably 60% by mass, and more preferably 50% by mass, and is usually 1 to 70% by mass, preferably 3 to 60% by mass, and more preferably 5 to 50% by mass.

[0086] [Urethane Resin (B)] Examples of the urethane resin (B) include the urethane resin (B) described in the resin composition 1, and the preferred types, physical properties, etc. are also the same as those described in the resin composition 1.

[0087] From the viewpoint of warp resistance, the content of the urethane resin (B) in the resin composition 3 is preferably 10 to 85% by mass, more preferably 15 to 70% by mass, even more preferably 18 to 65% by mass, particularly preferably 20 to 60% by mass, and especially preferably 25 to 55% by mass.

[0088] In addition, the mass ratio of the epoxy resin (A) to the urethane resin (B) in the resin composition 3 [(A):(B)] is preferably 70:30 to 1:99 from the viewpoint of warp resistance, more preferably 65:35 to 5:95, even more preferably 60:40 to 10:90, and particularly preferably 50:50 to 15:85.

[0089] [Epoxy Resin Curing Agent (C)] Examples of the epoxy resin curing agent (C) include the epoxy resin curing agent (C) described in the resin composition 1, and preferred types, physical properties, etc. are as described in the resin composition 1.

[0090] The content of the epoxy resin curing agent (C) is usually 0.001 to 20 parts by mass, preferably 0.01 to 10 parts by mass, and particularly preferably 0.1 to 5 parts by mass, relative to 100 parts by mass of the epoxy components contained in the resin composition 3 [for example, the total of the epoxy resin (A) and the liquid epoxy compound (d1)].

[0091] [Liquid Epoxy Compound (d1)] Examples of the liquid epoxy compound (d1) include the liquid epoxy compound (d1) described in the resin composition 1, and preferred types, physical properties, content, etc. are as described in the resin composition 1.

[0092] [Solid Epoxy Compound (d2)] From the viewpoint of heat resistance, the resin composition 3 forming the present film 3 preferably contains the solid epoxy compound (d2) described in the resin composition 1. The preferred type, physical properties, content, etc. of the solid epoxy compound (d2) are as described in the resin composition 1. As described above, the solid epoxy compound (d2) does not include the silane coupling agent (E).

[0093] [Silane Coupling Agent (E)] The resin composition 3 preferably contains a silane coupling agent (E). The preferred type, physical properties, content, etc. of the silane coupling agent (E) are the same as those described for the resin composition 1.

[0094] [Other Components] The resin composition 3 may optionally contain other components, such as resins other than epoxy resins, sensitizers, crosslinking agents, UV absorbers, polymerization inhibitors, fillers, antioxidants, leveling agents, slip agents, fine particles, dispersants, organic peroxides, reducing agents, radical polymerizable compounds, plasticizers, antifoaming agents, polymerization initiators, and elastomers, within a range that does not impair the effects of the present invention (for example, typically 10% by mass or less, preferably 5% by mass or less, of the resin composition 3). These may be used alone or in combination of two or more. For example, the incorporation of an elastomer tends to adjust the flexibility and impact resistance of the film when cured. Furthermore, the incorporation of a polymerization initiator, such as a thermal polymerization initiator (e.g., peroxide, azo compound) or a photopolymerization initiator, tends to adjust the strength of the film when cured.

[0095] The resin composition 3 can be obtained by uniformly mixing the epoxy resin (A), the urethane resin (B), the epoxy resin curing agent (C), the liquid epoxy compound (d1), and other components as required, in a conventional manner.

[0096] The types and skeletons of the epoxy resin (A), urethane resin (B), and liquid epoxy compound (d1) contained in the resin composition 3 can be confirmed by, for example, NMR (nuclear magnetic resonance spectroscopy), IR (infrared spectroscopy), SEM (scanning electron microscope) analysis, ICP (inductively coupled plasma) atomic emission spectroscopy, TGA (thermogravimetric analysis), DSC (differential scanning calorimetry), various types of chromatography, and the like.

[0097] From the viewpoint of heat resistance and warpage resistance, the resin composition 3 preferably has an epoxy equivalent measured in accordance with JIS K7236 of 400 to 50,000 g / eq, more preferably 600 to 10,000 g / eq, and particularly preferably 800 to 8,000 g / eq.

[0098] <Method for Producing the Present Film> The method for producing the present film is not particularly limited, and may be, for example, by forming the resin composition into a sheet and then heating it to semi-cure (primary curing).

[0099] When the resin composition is formed into a sheet, a solvent (G) may be added to the resin composition in order to improve the handleability of the resin composition.

[0100] [Solvent (G)] Examples of the solvent (G) include organic solvents such as aromatic solvents, alcohol solvents, ester solvents, ketone solvents, glycol ether solvents, glycol ester solvents, chlorine solvents, ether solvents, and amide solvents. These may be used alone or in combination of two or more. Among these, ketone solvents, aromatic solvents, and ester solvents are preferred.

[0101] Examples of the aromatic solvents include benzene, toluene, and xylene, with toluene being preferred. Examples of the alcohol solvents include lower alcohols having 1 to 5 carbon atoms, such as methanol, ethanol, and isopropyl alcohol. Examples of the ketone solvents include acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, 2-octanone, cyclopentanone, cyclohexanone, and acetylacetone, with methyl ethyl ketone being preferred. Examples of the glycol ether solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono-n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol monoethyl ether acetate, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono-n-butyl ether, diethylene glycol dimethyl ether, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether, propylene glycol mono-n-butyl ether, and propylene glycol monomethyl ether acetate. Examples of the amide solvent include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N-dimethylacetamide, 2-pyrrolidone, and N-methylpyrrolidone.

[0102] When the solvent (G) is used, it is preferably used so that the concentration of the resin composition is 10 to 90% by mass, more preferably 20 to 80% by mass. If the content of the solvent (G) is too low, the handling property tends to be reduced, whereas if the content of the solvent (G) is too high, the amount of residual solvent when the present film is formed increases, and the present film tends to be easily warped after curing.

[0103] The method for forming the resin composition into a sheet is not particularly limited, and examples thereof include a method in which the resin composition is coated onto a release film or a component of an image display device described below to form a sheet, and a method in which the resin composition is extruded using a die such as a T-die and then formed into a sheet using a cast roll or the like.

[0104] Examples of the coating method include known methods such as comma coating, gravure coating, reverse coating, knife coating, dip coating, spray coating, air knife coating, spin coating, roll coating, printing, slide coating, curtain coating, die coating, casting, bar coating, and extrusion coating.

[0105] The resin composition formed into a sheet is then semi-cured (primary cured) by heating. The heating conditions for semi-curing (primary curing) are adjusted appropriately depending on the components and amounts of the resin composition, but are typically 60 to 180°C for 1 to 180 minutes. In order to reduce curing defects, a two-stage treatment is preferred, in which primary heating is performed at 60 to 100°C for 1 to 30 minutes, followed by secondary heating at 100 to 180°C, which is 40 to 80°C higher than the primary heating temperature, for 1 to 150 minutes.

[0106] The thickness of the present film thus obtained is usually 1 to 1,000 μm, preferably 2 to 200 μm, and particularly preferably 5 to 50 μm. When the present film has a thickness within this range, it tends to have appropriate handleability.

[0107] After being applied to an adherend, this film is heated to completely cure (C-stage state) and exert its adhesive strength to the adherend.

[0108] The temperature for the heat treatment is preferably 120°C or higher, more preferably 150°C or higher, even more preferably 160°C or higher, and particularly preferably 170°C or higher. However, if the heating temperature is too high, the adhesive properties and reliability may be reduced due to decomposition or oxidative degradation of the epoxy component. Therefore, the upper limit of the heating temperature is usually 250°C, and preferably 220°C.

[0109] The duration of the heat treatment is not particularly limited as long as it allows the curing reaction of the resin composition constituting the present film to proceed sufficiently, but is usually from 5 minutes to 200 hours, preferably from 10 minutes to 150 hours. The heat treatment may also be carried out under reduced pressure.

[0110] The film after the heat treatment (cured present film) is preferably subjected to a cooling treatment. In terms of productivity, the cooling treatment is preferably carried out at a cooling rate of 0.1°C / min or more, more preferably 0.5°C / min or more, and even more preferably 1°C / min or more. On the other hand, in terms of reducing adhesion deterioration, adhesion unevenness, appearance unevenness, warpage, and the like associated with cooling distortion occurring inside the member or film, the cooling rate is preferably 40°C / min or less, more preferably 30°C / min or less, and even more preferably 20°C / min or less.

[0111] The number average molecular weights and epoxy equivalents of the epoxy resin (A), epoxy compound (D), liquid epoxy compound (F), etc. contained in the present film can be substituted by extracting the sol content from the present film and measuring the number average molecular weights and epoxy equivalents of the epoxy resin (A), epoxy compound (D), liquid epoxy compound (F), etc. in the sol content.

[0112] <Physical Properties of the Present Film> The present film can have the following physical properties.

[0113] From the viewpoint of warp resistance, the present film 1 or 3 has a storage modulus (E') of 1×10 at 100° C., measured by a dynamic viscoelasticity measuring device after curing. 7 Pa or less, preferably 6×10 6 Pa or less, particularly preferably 4 × 10 6 The lower limit is usually 1×10 4 Pa, preferably 1×10 5 Pa, for example, typically 1×10 4 ~1 x 10 7 Pa, preferably 1×10 5 ~6 x 10 6 It is Pa.

[0114] The storage modulus (E') at 100°C can be determined by cutting a 4 mm x 40 mm measurement sample from the cured film that has been heat-treated at a temperature of 170°C for 30 minutes, and measuring the dynamic viscoelasticity of the measurement sample in accordance with JIS K7244-4:1999 using a viscoelasticity spectrometer "DVA-200 (manufactured by IT Measurement & Control Co., Ltd.)" in a tensile mode under conditions of a frequency of 1 Hz, a strain of 0.1%, a temperature range of -50 to 300°C, and a heating rate of 3°C / min, and reading the value of the storage modulus (E') at 100°C.

[0115] Furthermore, in terms of heat resistance and warpage resistance, the cured film 1 or 3 has a loss tangent (Tanδ) of 5.0×10 at 50° C. as measured using a dynamic viscoelasticity measuring device. -2 It is preferable that the ratio is equal to or greater than 1.0×10 -1 More preferably, 5.0 × 10 -1 The upper limit is usually 1.0 × 10 2 and preferably 1.0 × 10 1 For example, it is usually 5.0 × 10 -2 ~1.0 x 10 2 , preferably 1.0×10 -1 ~1.0 x 10 1 is.

[0116] The loss tangent (Tan δ) at 50°C can be determined by cutting a 4 mm x 40 mm measurement sample from the cured film that has been heat-treated at a temperature of 170°C for 30 minutes, and measuring the loss tangent (Tan δ) at 50°C using a viscoelasticity spectrometer "DVA-200 (manufactured by IT Measurement & Control Co., Ltd.)" in accordance with JIS K7244-4:1999 in a tensile mode under conditions of a frequency of 1 Hz, a strain of 0.1%, a temperature range of -50 to 300°C, and a heating rate of 3°C / min.

[0117] When differential scanning calorimetry (DSC) is performed on the present film at a temperature rise rate of 10°C / min, the film preferably has an exothermic peak in the temperature range of 120 to 220°C, more preferably 130 to 200°C, and particularly preferably 140 to 190°C. The calorific value of the exothermic peak is preferably 5 J / g or more, more preferably 10 J / g or more, and particularly preferably 15 J / g or more. The upper limit is usually 100 J / g. When the present film has an exothermic peak with a specific calorific value in the above temperature range, the film tends to have excellent heat resistance and warp resistance.

[0118] The present film preferably has a glass transition temperature (Tg1) determined by DSC at a heating rate of 10°C / min of -40 to 120°C, more preferably 0 to 110°C, and particularly preferably 20 to 100°C. Furthermore, it is preferable that the exothermic peak temperature (T1) determined by DSC and the glass transition temperature (Tg1) satisfy the following relationship: T1 - Tg1 ≧ 60. Furthermore, in the present film, the difference between the exothermic peak temperature (T1) and the glass transition temperature (Tg1) is preferably 60°C or higher, more preferably 65°C or higher, and particularly preferably 80°C or higher, and is usually preferably 250°C or lower, more preferably 230°C or lower. In particular, in the present film 1 or 3, the difference between the exothermic peak temperature (T1) and the glass transition temperature (Tg1) is preferably 80°C or higher, more preferably 90°C or higher, and particularly preferably 95°C or higher. The upper limit is usually 250°C, and preferably 230°C. Furthermore, in the present film 2, the difference between the exothermic peak temperature (T1) and the glass transition temperature (Tg1) is preferably 65° C. or more, more preferably 70° C. or more, and particularly preferably 75° C. or more. The upper limit is usually 140° C., preferably 130° C. When the difference between the exothermic peak temperature (T1) and the glass transition temperature (Tg1) of the present film is within the above range, the film tends to have excellent heat resistance and warp resistance.

[0119] In view of warp resistance, the present film preferably has a solvent content of 10,000 ppm or less, more preferably 1,000 ppm or less, as detected by gas chromatography. The method for analyzing the residual solvent content by gas chromatography is as described in the Examples.

[0120] The present film preferably has a total light transmittance of 80% or more, more preferably 85% or more, and even more preferably 88% or more. The total light transmittance is measured in accordance with JIS K7361-1.

[0121] The haze of the present film is preferably 5% or less, more preferably 3% or less, and even more preferably 1% or less. When the haze of the present film is within the above range, it can be suitably used for flexible image display devices. The haze is measured in accordance with JIS K7136.

[0122] This film has little warping after curing, and is applied to a film with an area of ​​70 to 100 cm 2 After the film is heat-pressed to the adherend and thermally cured, the adherend is placed face down on a horizontal plate, and the average floating height of the four corners is preferably 10 mm or less. Examples of the adherend include resin sheets or glass, which are the main components of flexible image display device components described below. The thickness of the adherend is preferably 200 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0123] Furthermore, the adhesive strength of the present film to the adherend after curing is usually 2 N / cm or more, preferably 5 N / cm or more, particularly preferably 8 N / cm or more. The adhesive strength can be determined by the following method. A transparent polyimide (CPI) film (thickness 50 μm) cut to a width of 25 mm and a length of 150 mm is pressed onto the surface of the present film bonded to chemically strengthened glass under reduced pressure at a press pressure of 0.1 MPa and a temperature of 170 ° C. for 10 minutes to obtain an adhesive strength measurement sample. After fixing the adhesive strength measurement sample to a jig, the end of the test piece is fixed to the chuck of the testing machine, and the adhesive film is peeled from the adherend at a peel angle of 90 ° and a peel rate of 50 mm / min. The peel strength is measured with a load cell and used as the adhesive strength.

[0124] <Adhesive film with release film> From the viewpoint of ease of handling, the present film is preferably an adhesive film with a release film. That is, an adhesive film with a release film according to one embodiment of the present invention has a configuration in which a release film is laminated on the outermost surface of the present film. The release film is peeled off and removed when the present film is attached to an adherend. The release film may be laminated on only one outermost surface of the present film, or on both surfaces of the present film, but from the viewpoint of excellent simplicity of the production process, a configuration in which a release film is laminated on one outermost surface is preferred.

[0125] The thickness of the release film is usually 1 to 500 μm, preferably 5 to 300 μm, more preferably 10 to 200 μm, and even more preferably 20 to 150 μm. When a plurality of release films are present in the present film, it is preferable that the thickness of each layer is within the above range. The thickness (average thickness) of the release film is measured with a micrometer and calculated as the arithmetic mean of the measurements.

[0126] Examples of the substrate of the release film include thin films made from raw materials such as paper, resin, and metal. The release film may have a single layer structure or a multi-layer structure of two or more layers, as long as it does not deviate from the gist of the present invention. Among these, paper and resin films are preferred because they are inexpensive, easy to process, and easy to dispose of and recycle, and resin sheets are more preferred because of their transparency.

[0127] Examples of the paper that can be used include high-quality paper, kraft paper, glassine paper, parchment paper, and supercalendered kraft paper, the surface of which has been silicone-coated.

[0128] Examples of resin films include films mainly composed of polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyimide, or polycarbonate. The surface of these films may be coated with a silicone resin release agent, a melamine-based resin release agent, a fluorine-based release agent, or the like to adjust the peel strength. Among these, resin films mainly composed of polyester are preferred in terms of appearance, ease of processing, durability, heat resistance, cost, etc.

[0129] The polyester is preferably one obtained by polycondensation of an aromatic dicarboxylic acid and an aliphatic glycol. The polyester may be a polyester composed of one type of aromatic dicarboxylic acid and one type of aliphatic glycol, or a copolymer polyester in which one or more other components are further copolymerized. Examples of the aromatic dicarboxylic acid include terephthalic acid and 2,6-naphthalenedicarboxylic acid. Examples of the aliphatic glycol include ethylene glycol, diethylene glycol, and 1,4-cyclohexanedimethanol. Examples of the dicarboxylic acid used as the other component of the copolymerized polyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalenedicarboxylic acid, and sebacic acid. Examples of the glycol component include ethylene glycol, diethylene glycol, propylene glycol, butanediol, 1,4-cyclohexanedimethanol, and neopentyl glycol. Oxycarboxylic acids such as p-oxybenzoic acid can also be used. Typical examples of polyesters include polyethylene terephthalate obtained by polycondensation of terephthalic acid and ethylene glycol, and polyethylene naphthalate obtained by polycondensation of 2,6-naphthalenedicarboxylic acid and ethylene glycol.

[0130] The polyester film may be a non-stretched film or a stretched film, but is preferably a stretched film from the viewpoint of mechanical strength, and more preferably a biaxially stretched film. The polyester film may be previously subjected to a surface treatment such as a corona treatment or a plasma treatment.

[0131] The release film is preferably a matte film having minute irregularities formed on its surface, from the viewpoint of facilitating transfer to the present film and enhancing wettability of the release film during formation of the present film. The method for making the film matte is not particularly limited, and examples thereof include a method of providing a release layer containing a filler on the surface, sandblasting (sand matting), etc.

[0132] [Preferred Uses of the Film] The film can be suitably used for bonding components together, and in particular, it can be suitably used for bonding components of an image display device, i.e., as an adhesive film for components of an image display device. Specifically, it is suitably used for bonding components that constitute display members (also referred to as "display members"), particularly flexible components of an image display device used to produce a display.

[0133] <Laminate for image display device> A laminate for an image display device according to one embodiment of the present invention (hereinafter sometimes referred to as "the laminate for the image display device") is a laminate for an image display device having a configuration in which two components of the image display device are laminated with the present film interposed therebetween. Furthermore, the laminate for the image display device is preferably a laminate for a flexible image display device having a configuration in which two components of a flexible image display device are laminated with the present film interposed therebetween.

[0134] Of the components of the laminate for an image display device, the film has been described above, and the components other than the film will be described below.

[0135] (Image Display Device Components) Examples of image display device components constituting the present laminate for image display devices include flexible image display device components. Examples of the flexible image display device components include flexible displays such as organic electroluminescence (EL) displays, cover lenses (cover films), polarizing plates, polarizers, retardation films, barrier films, viewing angle compensation films, brightness enhancement films, contrast enhancement films, diffusion films, semi-transmitting reflective films, electrode films, transparent conductive films, metal mesh films, and touch sensor films. Any one of these may be used alone or in combination. Examples include a combination of a flexible display with another flexible image display device component, or a combination of a cover lens with another flexible image display device component.

[0136] The term "flexible image display device component" refers to a component having a curved or bendable portion, particularly a component having a portion that can be repeatedly bent. In particular, it is preferable that the component be a component that can be fixed into a curved shape with a curvature radius of 25 mm or more, and particularly a component that can withstand repeated bending with a curvature radius of less than 25 mm, more preferably less than 3 mm.

[0137] In the above-described configuration, the main component of the flexible image display device component may be a resin sheet or glass. Examples of materials for such a resin sheet include polyester resin, cycloolefin resin, triacetyl cellulose resin, polymethyl methacrylate resin, polyurethane, epoxy resin, polyimide resin, and aramid resin. These may be one type of resin or two or more types of resin. Among these, a resin sheet containing at least one resin selected from the group consisting of polyester resin, cycloolefin resin, triacetyl cellulose resin, polymethyl methacrylate resin, epoxy resin, polyimide resin, aramid resin, and polyurethane resin as its main component is preferred. Here, the term "main component" refers to the component that accounts for the largest weight percentage among the components constituting the flexible image display device component. Specifically, the main component is a component that accounts for 50% by weight or more of the resin composition (resin sheet) forming the flexible image display device component, preferably 55% by weight or more, and particularly preferably 60% by weight or more. The flexible image display device component may also be made of thin-film glass.

[0138] In the above-described configuration, it is preferable that one of the two flexible image display device constituent members, i.e., the first flexible image display device constituent member, has a tensile strength at 25°C measured in accordance with ASTM D882 of 10 to 900 MPa, more preferably 15 to 800 MPa, and particularly preferably 20 to 700 MPa. If the tensile strength (ASTM D882) at 25°C of one of the flexible image display device constituent members is within the above range, it is preferable because it is less likely to crack when bent.

[0139] Furthermore, the other flexible image display device component, i.e., the second flexible image display device component, preferably has a tensile strength at 25°C measured in accordance with ASTM D882 of 10 to 900 MPa, more preferably 15 to 800 MPa, and particularly preferably 20 to 700 MPa. If the tensile strength (ASTM D882) at 25°C of the other flexible image display device component is within the above range, it is preferable because it is less likely to crack when bent.

[0140] Examples of flexible image display device components with high tensile strength include polyimide films, polyester films, and aramid films, which generally have a tensile strength of 900 MPa or less. On the other hand, examples of flexible image display device components with somewhat low tensile strength include triacetyl cellulose (TAC) films and cycloolefin polymer (COP) films, which generally have a tensile strength of 10 MPa or more. Even if the present laminate for flexible image display devices includes flexible image display device components made of such materials with somewhat low tensile strength, defects such as cracking can be suppressed by the action of the present film.

[0141] <Method for manufacturing the present laminate for image display device> The method for manufacturing the present laminate for image display device is not particularly limited, and as described above, for example, the present film may be formed by applying the resin composition onto a component of an image display device, preferably onto a component of a flexible image display device, or the present film may be formed in advance and then laminated to a component of an image display device, preferably a component of a flexible image display device.

[0142] <Image display device> An image display device according to an example of an embodiment of the present invention (hereinafter, sometimes referred to as "the present image display device") is an image display device incorporating a laminate for an image display device having a configuration in which two image display device components are bonded together via the present film. For example, by laminating a laminate for an image display device having a configuration in which two image display device components are bonded together via the present film on another image display device component, the present image display device including the laminate can be formed.

[0143] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples as long as it does not depart from the gist of the invention. In the examples, "parts" refers to parts by mass.

[0144] Prior to the examples, the following materials were prepared.

[0145] [Epoxy Resin (A)] (A-1): Bisphenol A type epoxy resin ("jER1256B40" manufactured by Mitsubishi Chemical Corporation, number average molecular weight 45,000, epoxy equivalent 6,700 g / eq) (A'-1): Bisphenol A type epoxy resin ("jER1010" manufactured by Mitsubishi Chemical Corporation, number average molecular weight 30,000, epoxy equivalent 4,000 g / eq)

[0146] [Urethane Resin (B)] (B-1): Polyurethane resin ("Takelac TE-5899" manufactured by Mitsui Chemicals, Inc., storage modulus (E') at 20°C: 5.6 × 10 6 Pa, glass transition temperature (Tg) -37°C) (B-2): polyurethane resin ("MT Olestar NL2249E" manufactured by Mitsui Chemicals, Inc., storage modulus (E') at 20°C of 1.5 x 10 8 Pa, glass transition temperature (Tg) -27°C)

[0147] [Epoxy resin curing agents (C)] (C-1): 2-ethyl-4-methylimidazole ("Curesol 2E4MZ" manufactured by Shikoku Chemical Industries, Ltd.) (C-2): Polyoxypropylene diamine ("Jeffamine D-230" manufactured by HUNTSMAN, weight average molecular weight 230) (C-3): Polyoxypropylene diamine ("Jeffamine D-400" manufactured by HUNTSMAN, weight average molecular weight 400) (C-4): Polyoxypropylene diamine ("Jeffamine D-2000" manufactured by HUNTSMAN, weight average molecular weight 2,000)

[0148] [Epoxy Compounds (D)] (d1-1): urethane-modified epoxy resin ("EPU-73B" manufactured by ADEKA Corporation, viscosity at 25°C: 130,000 mPa·s, epoxy equivalent: 245 g / eq) (d1-2): epoxidized polybutadiene ("JP-200" manufactured by Nippon Soda Co., Ltd., viscosity at 45°C: 150,000 mPa·s, epoxy equivalent: 220 g / eq) (d2-1): bisphenol A novolac epoxy resin ("jER157S65B80" manufactured by Mitsubishi Chemical Corporation, softening point: 80°C, epoxy equivalent: 205 g / eq)

[0149] [Silane Coupling Agent (E)] (E-1): 3-glycidoxypropyltrimethoxysilane ("KBM-403" manufactured by Shin-Etsu Silicones Co., Ltd.)

[0150] [Liquid Epoxy Compounds (F)] (F-1): 2-ethylhexyl glycidyl ether ("YED188" manufactured by Mitsubishi Chemical Corporation, boiling point at 0.4 hPa: 61°C, equivalent boiling point at 1 atmosphere: 253°C, viscosity at 25°C: 4 mPa·s, epoxy equivalent: 180 to 196 g / eq) (F-2): 1,6-hexanediol diglycidyl ether ("YED216D" manufactured by Mitsubishi Chemical Corporation, boiling point at 6.7 hPa: 177°C, equivalent boiling point at 1 atmosphere: 344°C, viscosity at 25°C: 11 mPa·s, epoxy equivalent: 110 to 130 g / eq)

[0151] [Solvent (G)] (G-1): Toluene (G-2): Methyl ethyl ketone (G-3): Ethyl acetate (G-4): Isopropanol

[0152] [Release film] A release film consisting of a polyester film and a silicone-based release layer ("SP-PET (registered trademark) O3-BU" (100 μm) manufactured by Mitsui Chemicals Tocello Co., Ltd.)

[0153] Example 1 A resin composition was prepared by mixing epoxy resin (A-1), urethane resin (B-1), epoxy resin curing agent (C-1), and epoxy compound (d2-1) in the proportions shown in Table 1 below. Next, solvents (G-1) to (G-4) were mixed with the resin composition in the proportions shown in Table 1 below to prepare a resin composition. The epoxy equivalent of the resin composition was 5,198 g / eq. The prepared resin composition was applied to a release film using an applicator so that the thickness after drying would be 25 μm. The film was then heated at 120°C for 5 minutes using a constant temperature dryer, and then naturally cooled to room temperature (25°C). The resin composition was subjected to primary curing, resulting in the production of an adhesive film with a release film of Example 1.

[0154] Examples 2 to 9, Comparative Examples 1 to 3 Each resin composition was obtained in the same manner as in Example 1, except that the proportions of the materials in the resin composition were changed to the amounts shown in Table 1 below. The epoxy equivalent of each resin composition is shown in Table 1 below. Furthermore, adhesive films with release films of Examples 2 to 9 and Comparative Examples 1 and 2 were obtained in the same manner as in Example 1, except that each of the obtained resin compositions was used. Note that in Comparative Example 3, repelling occurred when the resin composition was applied to the release film, preventing the production of a uniform adhesive film, and subsequent evaluation was not possible.

[0155] The following evaluations were carried out using the resulting adhesive films with release films of Examples 1 to 9 and Comparative Examples 1 and 2. The results are shown in Table 1 below.

[0156] (1) Storage Modulus (E') and Loss Tangent (Tan δ) The adhesive films with release films produced in Examples 1 to 9 and Comparative Examples 1 and 2 were heat-treated at a temperature of 170 ° C. for 30 minutes. Thereafter, the release film was peeled off, and the adhesive film was cut into a 4 mm x 40 mm measurement sample. This measurement sample was subjected to dynamic viscoelasticity measurement in accordance with JIS K7244-4:1999 using a viscoelasticity spectrometer "DVA-200 (manufactured by IT Measurement & Control Co., Ltd.)" in tension mode under the conditions of a frequency of 1 Hz, a strain of 0.1%, a temperature range of -50 to 300 ° C., and a heating rate of 3 ° C. / min, and the storage modulus (E') value at 100 ° C. and the loss tangent (Tan δ) value at 50 ° C. were read.

[0157] (2) Glass transition temperature (Tg1) The release films were peeled off from the adhesive films with release films produced in Examples 1 to 9 and Comparative Examples 1 and 2, and the glass transition temperatures of the adhesive films were measured based on the "midpoint glass transition temperature: Tmg" of JIS K7121 "Method for measuring transition temperatures of plastics." Specifically, a differential scanning calorimeter "DSC8500" manufactured by PerkinElmer Japan was used to measure the glass transition temperature (Tg1) by increasing the temperature from 3 to 250°C at a rate of 10°C / min.

[0158] (3) Temperature (T1) and calorific value (J / g) of exothermic peak The DSC curve obtained in the (1) glass transition temperature (Tg1) measurement was checked for the presence or absence of an exothermic peak in the temperature range of 120°C or higher and 200°C or lower, and the temperature (T1) and calorific value (J / g) of the exothermic peak were determined.

[0159] (4) Solvent Content The solvent content was measured under the following conditions using HS-GC / MS (HS: "TurboMatrix HS 40" manufactured by PerkinElmer, GC / MS: "Clarus 580" manufactured by PerkinElmer). The release films were peeled off from the adhesive films with release films produced in Examples 1 to 9 and Comparative Examples 1 and 2, and 50 to 100 mg of adhesive film was collected and placed in a 20 mL vial and sealed. The vial containing the sample was then heated at 120°C for 30 minutes, and 0.2 mL of the heated gas was injected into a gas chromatograph (GC) using a headspace autosampler to measure the amount of residual solvent (toluene and methyl ethyl ketone). The measured value was converted to the content (emission amount) [ppm] contained per mass of the sample. [GC measurement device conditions] Column: TC-WAX 0.2 μm (diameter 0.25 mm × 30 m) Carrier gas: He 1.6 mL / min Column head pressure: 9.8 psi (40°C) Injection port: Split (split ratio 19:1, temperature 200°C) Column temperature: 40°C (5 min) - < +5°C / min > -150°C (0 min) (This means that the temperature was raised from 40°C to 150°C at a rate of 5°C / min, and then the measurement was completed without holding at 150°C.) Detector: FID (temperature 250°C)

[0160] (5) Total Light Transmittance, Haze The release films were peeled off from the adhesive films with release films produced in Examples 1 to 9 and Comparative Examples 1 and 2, and the haze of the adhesive films at 400 nm and 650 nm was measured in accordance with JIS (haze: JIS K 7136) using a haze meter "NDH 7000II" manufactured by Nippon Denshoku Industries Co., Ltd.

[0161] (6) Yellowness (b * The release film was peeled off from the adhesive film with release film produced in Examples 1 to 9 and Comparative Examples 1 and 2, and the yellowness index (b * The color chromaticity (color value) was measured in accordance with ASTM E313 using a spectrophotometer "SD6000" manufactured by Nippon Denshoku Industries Co., Ltd. The light source was C and the viewing angle was 2°.

[0162] (7) Adhesion Strength Chemically strengthened glass as an adherend was attached to the adhesive film surface of the adhesive film with a release film produced in Examples 1 to 9 and Comparative Examples 1 and 2 under reduced pressure (gauge pressure 60 × 10) using a vacuum laminator. -6 The adhesive film was then pressed at a pressure of 0.1 MPa, a temperature of 110°C, and pressure-bonded for 10 minutes. The release film was then peeled off to expose the adhesive film surface. A transparent polyimide (CPI) film (manufactured by Kolon Co., Ltd., thickness 50 μm) cut to a width of 25 mm and a length of 150 mm was then pressed onto the exposed adhesive film surface using a vacuum laminator under the same conditions as above, except that the temperature was 170°C, to obtain an adhesive strength measurement sample. After the adhesive strength measurement sample was fixed to a jig, the end of the test piece was fixed to the chuck of the testing machine, and the adhesive film was peeled off from the adherend at a peel angle of 90° and a peel rate of 50 mm / min. The peel strength was measured with a load cell to obtain the adhesive strength.

[0163] (8) Warpage Resistance A thin film tempered glass (UTG, manufactured by Nippon Electric Glass Co., Ltd.) measuring 65 mm × 160 mm × 32 μm thick was attached to the adhesive film surface of the adhesive film with release film produced in Examples 1 to 9 and Comparative Examples 1 and 2 under reduced pressure (gauge pressure: 60 × 10) using a vacuum laminator. -6The sample was pressed at a temperature of 170°C for 10 minutes at a pressure of 0.1 MPa. After that, it was cooled to room temperature (25°C), and the release film was peeled off to obtain a sample for curl measurement. The prepared sample was placed on a horizontal plate with the glass facing downwards, and the average height (mm) of the lifted corners was determined and evaluated according to the following evaluation criteria. [Evaluation criteria] ◯ (very good): The average height of the lifted corners is 10 mm or less × (poor): The average height of the lifted corners is more than 10 mm

[0164]

[0165] From the results in Table 1, it can be seen that the adhesive film formed from the resin composition containing the epoxy resin (A), the urethane resin (B), and the epoxy resin curing agent (C) has a storage modulus (E') of 1×10 at 100°C after curing. 7 It was confirmed that the adhesive films of Examples 1 to 9, which had a storage modulus (E') of 1×10 Pa or less, were excellent in warp resistance. 7 It was confirmed that the adhesive films of Examples 6 to 9, which had a storage modulus (E') of 1 x 10 at 100°C after curing, were excellent in warp resistance. Furthermore, it was confirmed that the adhesive films of Examples 1 to 9 had a high glass transition temperature and excellent heat resistance. On the other hand, the adhesive film of Comparative Example 1, which did not contain urethane resin (B), was poor in warp resistance. In addition, the storage modulus (E') at 100°C after curing was 1 x 10 7 Comparative Example 2, in which the epoxy equivalent was more than 5,000 g / eq, also had poor warpage resistance. In addition, in Comparative Example 3, in which an epoxy resin having an epoxy equivalent of less than 5,000 g / eq was used, an adhesive film could not be formed from the resin composition.

[0166] Example 10 A resin composition was prepared by mixing epoxy resin (A-1), liquid epoxy compound (F-1), solid epoxy compound (d2-1), and epoxy resin curing agent (C-1) in the ratios shown in Table 2 below. Next, a solvent (G-2) was mixed with the resin composition in the ratios shown in Table 2 below to prepare a resin composition. The epoxy equivalent of the resin composition was 682 g / eq. The prepared resin composition was applied to a release film using an applicator so that the thickness after drying would be 10 μm, and the film was heated at 120°C for 5 minutes using a constant temperature dryer, and then naturally cooled to room temperature (25°C) to primarily cure the resin composition, thereby obtaining an adhesive film with a release film of Example 10.

[0167] Examples 11 to 13, Comparative Example 4 Each resin composition was obtained in the same manner as in Example 10, except that the proportions of each material in the resin composition were changed to the amounts shown in Table 2 below. The epoxy equivalent of each resin composition is shown in Table 2 below. Furthermore, adhesive films with release films of Examples 11 to 13 and Comparative Example 4 were obtained in the same manner as in Example 10, except that each of the obtained resin compositions was used.

[0168] The following evaluations were carried out using the resulting adhesive films with release films of Examples 10 to 13 and Comparative Example 4. The results are shown in Table 2 below.

[0169] (9) Glass transition temperature (Tg1) The release films were peeled off from the adhesive films with release films produced in Examples 10 to 13 and Comparative Example 4, and the glass transition temperatures of the adhesive films were measured based on the "midpoint glass transition temperature: Tmg" of JIS K7121 "Method for measuring transition temperatures of plastics." Specifically, a differential scanning calorimeter "DSC8500" manufactured by PerkinElmer Japan was used to measure the glass transition temperature (Tg1) by increasing the temperature from 3 to 250°C at a rate of 10°C / min.

[0170] (10) Temperature (T1) and calorific value (J / g) of exothermic peak The DSC curve obtained in the above (1) glass transition temperature (Tg1) measurement was checked for the presence or absence of an exothermic peak in the temperature range of 120°C or higher and 200°C or lower, and the temperature (T1) and calorific value (J / g) of the exothermic peak were determined.

[0171] (11) Solvent Content The solvent content was measured under the following conditions using HS-GC / MS (HS: "TurboMatrix HS 40" manufactured by PerkinElmer, GC / MS: "Clarus 580" manufactured by PerkinElmer). The release film was peeled off from the adhesive film with release film produced in Examples 10 to 13 and Comparative Example 4, and 50 to 100 mg of adhesive film was collected and placed in a 20 mL vial and sealed. The vial containing the sample was then heated at 120 ° C. for 30 minutes, and 0.2 mL of the heated gas was injected into a gas chromatograph (GC) using a headspace autosampler to measure the amount of residual solvent (toluene and methyl ethyl ketone). The measured value was converted to the content (emission amount) [ppm] contained per mass of the sample. [GC measurement device conditions] Column: TC-WAX 0.2 μm (diameter 0.25 mm × 30 m) Carrier gas: He 1.6 mL / min Column head pressure: 9.8 psi (40°C) Injection port: Split (split ratio 19:1, temperature 200°C) Column temperature: 40°C (5 min) - < +5°C / min > -150°C (0 min) (This means that the temperature was raised from 40°C to 150°C at a rate of 5°C / min, and then the measurement was completed without holding at 150°C.) Detector: FID (temperature 250°C)

[0172] (12) Adhesion Strength Chemically strengthened glass as an adherend was attached to the adhesive film surface of the adhesive film with a release film produced in Examples 10 to 13 and Comparative Example 4 under reduced pressure (gauge pressure 60 × 10) using a vacuum laminator. -6 The adhesive film was then pressed at a pressure of 0.1 MPa, a temperature of 110°C, and pressure-bonded for 10 minutes. The release film was then peeled off to expose the adhesive film surface. A transparent polyimide (CPI) film (manufactured by Kolon Co., Ltd., thickness 50 μm) cut to a width of 25 mm and a length of 150 mm was then pressed onto the exposed adhesive film surface using a vacuum laminator under the same conditions as above, except that the temperature was 170°C, to obtain an adhesive strength measurement sample. After the adhesive strength measurement sample was fixed to a jig, the end of the test piece was fixed to the chuck of the testing machine, and the adhesive film was peeled off from the adherend at a peel angle of 90° and a peel rate of 50 mm / min. The peel strength was measured with a load cell to obtain the adhesive strength.

[0173] (13) Warp Resistance A thin film tempered glass (UTG, manufactured by Nippon Electric Glass Co., Ltd.) measuring 65 mm x 160 mm x 32 μm thick was attached to the adhesive film surface of the adhesive film with release film produced in Examples 10 to 13 and Comparative Example 4 under reduced pressure (gauge pressure: 60 × 10 -6 The sample was pressed at a temperature of 170°C for 10 minutes at a pressure of 0.1 MPa. After that, it was cooled to room temperature (25°C), and the release film was peeled off to obtain a sample for curl measurement. The prepared sample was placed on a horizontal plate with the glass facing downwards, and the average height (mm) of the lifted corners was determined and evaluated according to the following evaluation criteria. [Evaluation criteria] ◯ (very good): The average height of the lifted corners is 10 mm or less × (poor): The average height of the lifted corners is more than 10 mm

[0174] (14) Total Light Transmittance, Haze The release films were peeled off from the adhesive films with release films produced in Examples 10 to 13 and Comparative Example 4, and the haze of the adhesive films at 400 nm and 650 nm was measured in accordance with JIS (haze: JIS K 7136) using a haze meter "NDH 7000II" manufactured by Nippon Denshoku Industries Co., Ltd.

[0175]

[0176] From the results in Table 2, the adhesive films of Examples 10 to 13 formed from resin compositions containing epoxy resin (A) and liquid epoxy compound (F) were excellent in warp resistance. Furthermore, the adhesive films of Examples 10 to 13 had high glass transition temperatures and excellent heat resistance. On the other hand, the adhesive film of Comparative Example 4, which did not contain liquid epoxy compound (F), was poor in warp resistance. Furthermore, the adhesive film of Comparative Example 4 had a large amount of residual solvent, which resulted in impaired suitability for subsequent processes.

[0177] Although the above examples show specific embodiments of the present invention, the examples are merely illustrative and should not be construed as limiting. Various modifications that are obvious to those skilled in the art are intended to fall within the scope of the present invention.

[0178] The film exhibits little warping after curing and has excellent heat resistance, and therefore can be suitably used in various laminates, and is particularly useful as an adhesive film for components of image display devices.

Claims

1. An adhesive film formed from a resin composition containing an epoxy resin (A) having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, a urethane resin (B), and an epoxy resin curing agent (C), and the adhesive film has a storage modulus (E') at 100°C after curing of 1 x 10 7 An adhesive film having a viscosity of 0.1 Pa or less.

2. The adhesive film according to claim 1, which has a loss tangent (Tan δ) of 0.1 or more at 50°C after curing.

3. The adhesive film according to claim 1 or 2, wherein the resin composition further contains an epoxy compound (D) having an epoxy equivalent of 1,000 g / eq or less.

4. The adhesive film according to claim 3, wherein the epoxy compound (D) comprises a urethane-modified epoxy compound.

5. An adhesive film according to claim 1 or 2, wherein the content of the urethane resin (B) in the resin composition is 10 to 85 mass %.

6. The adhesive film according to claim 1 or 2, wherein the epoxy resin curing agent (C) comprises an amine-based curing agent.

7. The storage modulus (E') of the urethane resin (B) at 20°C is 1 x 10 7 The adhesive film according to claim 1 or 2, wherein the elastic modulus is 0.01 Pa or less.

8. An adhesive film formed from a resin composition containing an epoxy resin (A) having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, and a liquid epoxy compound (F) having a boiling point of 170°C or more at 1 atmospheric pressure (excluding the epoxy resin (A)).

9. The adhesive film according to claim 8, wherein the liquid epoxy compound (F) has an epoxy equivalent of 1,000 g / eq or less.

10. An adhesive film according to claim 8 or 9, wherein the resin composition contains a solid epoxy compound (d2) having an epoxy equivalent of 1,000 g / eq or less.

11. An adhesive film according to claim 8 or 9, wherein the mass ratio [(A):(F)] of the epoxy resin (A) to the liquid epoxy compound (F) in the resin composition is 95:5 to 50:

50.

12. An adhesive film according to claim 10, wherein the mass ratio [(A):(d2)] of the epoxy resin (A) to the solid epoxy compound (d2) in the resin composition is 99:1 to 50:

50.

13. The adhesive film according to claim 8 or 9, wherein the resin composition contains an epoxy resin curing agent (C).

14. The adhesive film according to claim 13, wherein the epoxy resin curing agent (C) comprises an amine-based curing agent.

15. An adhesive film formed from a resin composition containing an epoxy resin (A) having a number average molecular weight of 10,000 or more and an epoxy equivalent of 5,000 g / eq or more, a urethane resin (B), an epoxy resin curing agent (C), and a liquid epoxy compound (d1) having an epoxy equivalent of 1,000 g / eq or less, the adhesive film having a storage modulus (E') at 100°C after curing of 1 x 10 7 An adhesive film having a viscosity of 0.1 Pa or less.

16. The adhesive film according to claim 15, wherein the epoxy resin curing agent (C) comprises an amine-based curing agent.

17. The adhesive film according to any one of claims 1, 8 and 15, wherein the resin composition has an epoxy equivalent of 400 to 50,000 g / eq.

18. An adhesive film according to any one of claims 1, 8 and 15, which has an exothermic peak in the temperature range of 120 to 220°C when subjected to differential scanning calorimetry (DSC) at a heating rate of 10°C / min, and the heat quantity of the exothermic peak is 5 J / g or more.

19. An adhesive film according to claim 18, which has a glass transition temperature (Tg1) determined by differential scanning calorimetry (DSC) at a heating rate of 10°C / min of 0 to 120°C, and the temperature (T1) of the exothermic peak in the differential scanning calorimetry (DSC) and the glass transition temperature (Tg1) satisfy the following relationship: T1-Tg1≧60 20. An adhesive film according to any one of claims 1, 8 and 15, having a solvent content of 10,000 ppm or less.

21. An adhesive film according to any one of claims 1, 8 and 15, having a total light transmittance of 80% or more and a haze of 5% or less.

22. An adhesive film with a release film, comprising the adhesive film according to any one of claims 1, 8 and 15 laminated with a release film.

23. An adhesive film for use as a component of a flexible image display device, comprising the adhesive film according to any one of claims 1, 8 and 15.

24. A laminate for a flexible image display device, comprising two image display device components laminated together via the adhesive film according to any one of claims 1, 8 and 15.

25. The laminate for a flexible image display device according to claim 24, having curved or bendable portions.

26. A flexible image display comprising the laminate for a flexible image display according to claim 24.

Images