TW202323043A - Laminate body, epoxy film and wound body - Google Patents

Abstract

This laminate body is provided at least with an epoxy resin layer, which is obtained by curing an epoxy resin composition that contains an epoxy resin (A) and an isocyanate compound (B), and a separation film. The epoxy resin (A) contains substantially no tri- or more functional epoxy resin, and when measuring the epoxy resin layer with DSC measurement, the temperature is increased to 20-250 DEG C at 10 DEG C/min, is then is decreased to 0 DEG C at 10 DEG C/min and is again increased to 0-250 DEG C at 10 DEG C/min, and the difference (T2-T1) between the glass transition temperature (T2) when increasing the temperature the second time and the glass transition temperature (T1) when increasing the temperature (T1) the first time is within 3 DEG C. An epoxy film can be achieved with good productivity and without problems occurring in post-processing.

Description

Laminates, epoxy films and rolls

The present invention relates to a laminated body, an epoxy film and a winding body.

Epoxy resins are used in various fields such as paints, civil engineering, adhesives, and electronic components because of their excellent heat resistance, adhesiveness, water resistance, mechanical strength, and electrical properties.

For example, Patent Document 1 discloses a curable resin composition using a specific polymer polyether polyol resin, a trifunctional or more functional epoxy resin, and an epoxy resin hardener, and describes a method obtained by curing the composition. Since the cured product has excellent heat resistance and bending resistance, it can be applied to a foldable OLED (organic light emitting diode, organic light emitting diode) display. prior art literature patent documents

Patent Document 1: International Publication No. 2020/080292

[Problem to be solved by the invention]

However, the curable resin composition described in the above-mentioned Patent Document 1 needs to be further improved in terms of productivity because the curing time is as long as 1 hour.

On the other hand, when a film containing an epoxy resin is used for an electronic component or the like, functional layers such as a hard coat layer or wiring may be provided on the film in a subsequent step. Therefore, the surface of the film is required to have good wettability to the functional layer or wiring. However, depending on the material of the film and its production method, it can be seen that the water droplet contact angle on the surface of the film may become high, and problems such as poor adhesion may occur in subsequent steps.

Therefore, the object of the present invention is to obtain an epoxy film which is good in productivity and does not cause troubles in the subsequent steps. [Technical means to solve the problem]

The inventors of the present invention have found that, in the case of forming a film by applying a coating liquid containing an epoxy resin composition to a release film, by substantially not containing an epoxy resin having a trifunctional or higher function and using an isocyanate compound in combination, It can shorten the time required for the hardening of the epoxy film, and as a result, the contact time with the release surface can be reduced, which can solve the above problems.

That is, the present invention has the following aspects. [1] A laminate comprising at least an epoxy resin layer formed by curing an epoxy resin composition containing an epoxy resin (A) and an isocyanate compound (B), and a release film, and The epoxy resin (A) does not substantially contain a trifunctional or higher epoxy resin, Measured by DSC (differential scanning calorimetry, differential scanning calorimetry), the temperature is raised from 20°C to 250°C at 10°C/min, and then the temperature is lowered to 0°C at 10°C/min, and then from 0°C to 250°C When measuring the above-mentioned epoxy resin layer by reheating at 10°C/min, the difference (T2-T1) between the glass transition temperature (T2) during reheating and the glass transition temperature (T1) during heating is within 3°C. [2] The laminate according to the above [1], wherein the epoxy resin (A) is a resin obtained by reacting an epoxy compound and a phenol compound. [3] The laminate according to the above [2], wherein the epoxy compound is a compound having two or less epoxy groups in a molecule. [4] The laminate according to the above [2] or [3], wherein the phenolic compound is a compound having two or more hydroxyl groups bonded to an aromatic ring. [5] The laminate according to any one of the above [1] to [4], wherein the epoxy resin (A) has a molecular weight of 2,000 to 300,000. [6] The laminate according to any one of [1] to [5] above, wherein the isocyanate compound (B) is a compound having an aliphatic isocyanate as a main skeleton. [7] The laminate according to any one of the above [1] to [6], wherein the epoxy resin composition contains a leveling agent. [8] The laminate according to the above [7], wherein the leveling agent includes a silicone skeleton and a polyether skeleton. [9] The laminate according to the above [7] or [8], wherein the leveling agent does not contain an acrylic skeleton. [10] The laminate according to any one of [1] to [9] above, wherein the glass transition temperature of the epoxy resin layer is 100° C. or higher. [11] A method for producing the laminate as described in any one of [1] to [10] above, which comprises a heat treatment at 80°C to 160°C and a temperature 40 to 120°C higher than that of the heat treatment at the first time The second heat treatment at 120-200°C hardens the above-mentioned epoxy resin composition. [12] An epoxy film in which the water droplet contact angles on both surfaces of the epoxy resin layer comprising the epoxy resin composition containing the epoxy resin (A) and the isocyanate compound (B) are 84 degrees or less. [13] The epoxy film as described in [12] above, which has a functional layer on at least one surface. [14] A wound body in which the laminate described in any one of [1] to [10] above or the epoxy film described in [12] or [13] above is wound around a core made. [15] The laminate according to any one of [1] to [10] above, which is used for a display. [16] The epoxy film as described in [12] or [13] above, which is used for a display. [Effect of Invention]

According to the present invention, it is possible to obtain an epoxy film which is good in productivity and does not cause problems in subsequent steps.

One embodiment of the present invention will be described below. However, this invention is not limited to the following embodiment, Various changes are possible in the range which does not deviate from the summary of this invention.

＜＜Laminate (1)＞＞ A laminate (1) (hereinafter also referred to as "this laminate (1)") according to one embodiment of the present invention is a laminate comprising at least epoxy resin (A) and isocyanate compound (B). The epoxy resin layer and the release film formed by hardening the resin composition, and the above-mentioned epoxy resin (A) does not substantially contain the epoxy resin with more than three functionalities, measured by DSC, from 20°C to 250°C at 10 ℃/min to heat up, then cool down to 0°C at 10°C/min, then reheat at 10°C/min from 0°C to 250°C to measure the glass transition temperature of the above epoxy resin layer when reheating The difference (T2-T1) between (T2) and the glass transition temperature (T1) at the time of heating is within 3°C. In this laminate (1), the epoxy resin composition contains the isocyanate compound (B) as a crosslinking agent, and the above-mentioned epoxy resin (A) does not substantially contain a trifunctional or higher functional epoxy resin, so the time required for curing Shorter and more productive. In addition, the water droplet contact angles of both surfaces of the epoxy resin layer of the laminate (1) are preferably 84 degrees or less, so that even if functional layers or wiring are installed in subsequent steps, it is difficult to cause problems such as poor adhesion. Furthermore, in the present invention, although the reason why the water droplet contact angle on both surfaces of the epoxy resin layer is 84 degrees or less is not clear, it is considered that the reason is that the hardening time of the epoxy resin composition is relatively short, so the release of the epoxy resin composition is prevented. Transfer of hydrophobic components contained in the film, or segregation of hydrophobic groups contained in epoxy resin compositions, etc.

＜Epoxy resin layer＞ The epoxy resin layer in this embodiment hardens the epoxy resin composition containing an epoxy resin (A) and an isocyanate compound (B).

[Epoxy resin composition] Hereinafter, each component which comprises an epoxy resin composition is demonstrated.

1. Epoxy resin (A) As the epoxy resin (A) in this embodiment, for example, alcohol type epoxy resin, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol C type epoxy resin, bisphenol S type epoxy resin, naphthalene type epoxy resin, phenol novolak type epoxy resin, cresol novolac type epoxy resin, bisphenol A novolak type epoxy resin, biphenyl type epoxy resin, triphenylmethane type Epoxy resin, dicyclopentadiene epoxy resin, glycidyl ester epoxy resin, glycidylamine epoxy resin, phenolic epoxy resin, aliphatic epoxy resin, alicyclic epoxy resin, hetero Cyclic epoxy resin, and epoxy resin with any combination of these structures, etc. The epoxy resin (A) in this embodiment may use only 1 type of the epoxy resin illustrated above, and may use 2 or more types together in arbitrary combinations and ratios.

骨架、金剛烷骨架及二環戊二烯骨架中之至少一種骨架之環氧樹脂，就耐熱性之觀點而言，更佳為使用具有苯基骨架、茀骨架及聯苯骨架中之至少一種之環氧樹脂，就製造之容易性及耐熱性之觀點而言，進而較佳為使用具有雙酚A骨架、雙酚F骨架及聯苯骨架中之至少一種骨架之環氧樹脂。 環氧樹脂(A)之種類及骨架可藉由NMR(Nuclear Magnetic Resonance Spectroscopy，核磁共振光譜法)、IR(infrared radiation，紅外光譜法)、SEM(scanning electron microscope，掃描式電子顯微鏡)分析、IPC(高頻感應耦合電漿)發射光譜分析法、TGA(thermogravimetric analysis，熱重量分析)、DSC(differential scanning calorimetry，示差掃描熱量測定)及各種層析法等進行確認。 Among them, as the epoxy resin (A) in the present embodiment, it is preferable to use a resin having a phenyl skeleton (phenol skeleton), a naphthalene skeleton, a fennel skeleton, a biphenyl skeleton, an anthracene skeleton, a pyrene skeleton, a

As the epoxy resin having at least one skeleton among the skeleton, the adamantane skeleton, and the dicyclopentadiene skeleton, it is more preferable to use one having at least one of the phenyl skeleton, the fennel skeleton, and the biphenyl skeleton from the viewpoint of heat resistance. As the epoxy resin, it is more preferable to use an epoxy resin having at least one skeleton of a bisphenol A skeleton, a bisphenol F skeleton, and a biphenyl skeleton from the viewpoint of easiness of manufacture and heat resistance. The type and skeleton of the epoxy resin (A) can be analyzed by NMR (Nuclear Magnetic Resonance Spectroscopy, nuclear magnetic resonance spectroscopy), IR (infrared radiation, infrared spectroscopy), SEM (scanning electron microscope, scanning electron microscope), IPC (High-frequency inductively coupled plasma) emission spectroscopic analysis, TGA (thermogravimetric analysis, thermogravimetric analysis), DSC (differential scanning calorimetry, differential scanning calorimetry) and various chromatography methods for confirmation.

As the epoxy resin (A) in this embodiment, the epoxy resin (α) shown below is preferable.

(epoxy resin (α)) The epoxy resin (α) is formed by reacting an epoxy compound and a phenolic compound.

＝Epoxy compound＝ As an epoxy compound in this Embodiment, the compound which has 2 or less epoxy groups in a molecule|numerator is preferable. As this compound, a bifunctional epoxy compound is mentioned.

Bifunctional epoxy compounds include, for example, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol E diglycidyl ether, bisphenol C diglycidyl ether, bisphenol Z diglycidyl ether Ether, bisphenol S diglycidyl ether, bisphenol AD diglycidyl ether, bisphenol acetophenone diglycidyl ether, bisphenol trimethylcyclohexane diglycidyl ether, bisphenol trimethylcyclohexane diglycidyl ether, bisphenol fennel diglycidyl ether, four Methyl bisphenol A diglycidyl ether, tetramethyl bisphenol F diglycidyl ether, tetra-tertiary butyl bisphenol A diglycidyl ether, tetramethyl bisphenol S diglycidyl ether, etc. Glycidyl ethers; biphenol diglycidyl ether, tetramethyl biphenol diglycidyl ether, dimethyl biphenol diglycidyl ether, tetra-tertiary butyl biphenol diglycidyl ether, etc. Glyceryl ethers; Hydroquinone diglycidyl ether, methyl hydroquinone diglycidyl ether, dibutylhydroquinone diglycidyl ether, resorcinol diglycidyl ether, methyl resorcinol Diphenol-based diglycidyl ethers such as phenol diglycidyl ether; dihydroanthracene hydroquinone diglycidyl ether, dihydroxydiphenyl ether diglycidyl ether, thiobiphenol diglycidyl ether, dihydroxynaphthalene diglycidyl ether etc.

In addition, it can also be exemplified: an epoxy compound obtained by adding hydrogen to the aromatic ring of the bifunctional epoxy compound exemplified above; adipic acid, succinic acid, phthalic acid, tetrahydrophthalic acid Formic acid, methylhexahydrophthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, biphenyl dicarboxylic acid, dimer acid and other carboxylic acids and epihalohydrin production ring Oxygen compounds; epoxy compounds made from various amine compounds such as diaminodiphenylmethane, aminophenol, xylylenediamine and epihalohydrin; only ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, poly-1,4-butanediol diglycidyl ether, 1,5-pentanediol diglycidyl ether Ether, poly-1,5-pentanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, poly-1,6-hexanediol diglycidyl ether, 1,7-heptanediol diglycidyl ether ether, poly 1,7-heptanediol diglycidyl ether, 1,8-octanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, 2,2-dimethyl-1,3 -(poly)alkylene glycol diglycidyl ether with a chain structure such as propylene glycol diglycidyl ether; alkylene glycol diglycidyl ether with a ring structure such as 1,4-cyclohexanedimethanol diglycidyl ether Glyceryl ether etc.

As the epoxy compound in this embodiment, only one of the epoxy compounds exemplified above may be used, or two or more of them may be used in any combination and ratio. Among these, bifunctional epoxy compounds are preferred from the viewpoint of suppressing gelation during the reaction and obtaining a copolymer having a molecular weight suitable for film formation, and more preferably from the viewpoint of transparency of the epoxy resin layer. Bisphenol-based diglycidyl ethers are preferable, and among them, bisphenol A diglycidyl ether is more preferable from the viewpoint of transparency and heat resistance of the epoxy resin layer.

In addition, the epoxy resin (A) must not substantially contain a trifunctional or higher epoxy resin. Here, "substantially free" means containing 2.0 parts by mass or less of a trifunctional or higher epoxy resin, preferably 1.5 parts by mass or less, particularly preferably 1.0 parts by mass, with respect to 100 parts by mass of epoxy resins within a bifunctionality. It is not more than 0.5 parts by mass, preferably not more than 0.5 parts by mass. By satisfying the above range, the curing reaction of the epoxy resin proceeds rapidly, and an epoxy film having desired properties (wettability of the film surface, bending resistance) can be obtained.

＝Phenolic compound＝ The phenolic compound in this embodiment is preferably a compound having two or more hydroxyl groups bonded to an aromatic ring.

Examples of phenolic compounds include bisphenol A, bisphenol F, bisphenol E, bisphenol C, bisphenol Z, bisphenol S, bisphenol AD, bisphenol acetophenone, bisphenol trimethylcyclo Bisphenols such as hexane, bisphenol fennel, tetramethylbisphenol A, tetramethylbisphenol F, tetra-tertiary butylbisphenol A, tetramethylbisphenol S; biphenol, tetramethylbiphenol , dimethyl biphenol, tetra-tertiary butyl biphenol and other biphenols; hydroquinone, methyl hydroquinone, dibutyl hydroquinone, resorcinol, methyl resorcinol Dihydroquinones such as phenol; dihydroanthracene hydroquinones such as dihydroanthracene hydroquinone; dihydroxydiphenyl ethers such as dihydroxydiphenyl ether; thiobiphenols such as thiobiphenol; Dihydroxynaphthalene such as naphthalene; dihydroxystilbene such as dihydroxystilbene; bisphenol novolac resin such as phenol novolac resin, cresol novolak resin, bisphenol A novolak resin; naphthol novolac resin, Various phenol resins such as phenol aralkyl resins, terpene phenol resins, dicyclopentadiene phenol resins, phenol biphenyl resins, phenol-modified xylene resins, and hydroxybenzaldehyde, croton, etc. Polyphenol resins obtained by the condensation reaction of various aldehydes such as aldehydes and glyoxal; various phenolic compounds such as co-condensation resins of heavy oil or asphalt, phenols and formaldehyde, etc.

As the phenolic compound in this embodiment, only one of the above-exemplified phenolic compounds may be used, or two or more of them may be used in any combination and ratio. Among them, bisphenol is preferable from the viewpoint of suppressing gelation when reacting with the above-mentioned glycidyl ether, and obtaining a copolymer having a molecular weight suitable for film formation, and the transparency and heat resistance of the epoxy resin layer. kind.

=Amount of epoxy compound and phenolic compound used= When preparing the epoxy resin (α), the amount of the phenolic compound used is preferably 0.05 mole or more, more preferably 0.10 mole or more, more preferably 0.15 mole or more, and more preferably 0.15 mole or more, relative to 1.00 mole of the epoxy compound. More preferably, it is 0.20 mol or more. On the other hand, with respect to 1.00 mol of the epoxy compound, the use amount of the phenolic compound is preferably 1.25 mol or less, more preferably 1.20 mol or less, further preferably 1.15 mol or less, still more preferably 1.10 mol below the ears. When the usage-amount of a phenolic compound is more than the said lower limit, molecular weight will increase, and it is preferable in this point. Especially within this range, when it is desired to obtain a low molecular weight epoxy compound, the amount of the phenolic compound can be reduced, and when it is desired to obtain a high molecular weight epoxy compound, the amount of the phenolic compound can be increased. On the other hand, since it is easy to obtain the epoxy compound with favorable curability as it is below the said upper limit, it is preferable.

＝Catalyst＝ When producing an epoxy resin (α), the above-mentioned epoxy compound and the above-mentioned phenolic compound can be reacted using a catalyst. The catalyst used in the production of the epoxy resin (α) is not particularly limited, as long as it is a compound capable of promoting the reaction of epoxy groups with phenolic hydroxyl groups, alcoholic hydroxyl groups or carboxyl groups. As a catalyst, an alkali metal compound, an organophosphorus compound, a tertiary amine, a quaternary ammonium salt, cyclic amines, imidazoles etc. are mentioned, for example.

Examples of the alkali metal compound include: alkali metal hydroxides such as sodium hydroxide, lithium hydroxide, and potassium hydroxide; alkali metals such as sodium carbonate, sodium bicarbonate, sodium chloride, lithium chloride, and potassium chloride; Salts; alkali metal alkoxides such as sodium methoxide and sodium ethoxide; alkali metal phenoxides; alkali metal hydrides such as sodium hydride and lithium hydride; alkali metal salts of organic acids such as sodium acetate and sodium stearate, etc.

Specific examples of the above organophosphorus compounds include: tri-n-propylphosphine, tri-n-butylphosphine, triphenylphosphine, tetramethylphosphonium bromide, tetramethylphosphonium iodide, tetramethylphosphonium hydroxide , Trimethylcyclohexylphosphonium chloride, Trimethylcyclohexylphosphonium bromide, Trimethylbenzylphosphonium chloride, Trimethylbenzylphosphonium bromide, Tetraphenylphosphonium bromide, Triphenylmethyl bromide Phosphonium, triphenylmethylphosphonium iodide, triphenylethylphosphonium chloride, triphenylethylphosphonium bromide, triphenylethylphosphonium iodide, triphenylbenzylphosphonium chloride, bromide Triphenylbenzylphosphonium, etc.

As said tertiary amines, triethylamine, tri-n-propylamine, tri-n-butylamine, triethanolamine, dimethylbenzylamine, etc. are mentioned, for example.

As the above-mentioned quaternary ammonium salt, for example, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium hydroxide, triethylmethylammonium chloride, tetraethylammonium chloride, bromine Tetraethylammonium chloride, tetraethylammonium iodide, tetrapropylammonium bromide, tetrapropylammonium hydroxide, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, tetrabutylammonium chloride Benzyltrimethylammonium, benzyltrimethylammonium bromide, benzyltrimethylammonium hydroxide, benzyltributylammonium chloride, phenyltrimethylammonium chloride, and the like.

Examples of the cyclic amines include: 1,8-diazabicyclo(5,4,0)-7-undecene, 1,5-diazabicyclo(4,3,0)-5 - Nonene etc.

As said imidazoles, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole etc. are mentioned, for example.

In addition, as other catalysts in this embodiment, only one of the compounds exemplified above may be used, or two or more of them may be used in any combination and ratio.

In the reaction solids, the amount of the catalyst used is generally preferably 0.001 to 1% by mass. When the usage-amount of a catalyst is more than the said lower limit, it becomes easy to achieve high molecular weight, and when the usage-amount of a catalyst is below the said upper limit, it becomes easy to suppress gelation. Furthermore, the reaction solid content refers to the total of the reaction substrates in the reaction system except the solvent.

＝Solvent＝ When preparing an epoxy resin (α), a solvent may be used in the step of reacting the epoxy compound and the phenolic compound. The above-mentioned solvent is not particularly limited, as long as it dissolves epoxy compounds, phenolic compounds and other raw materials, it is usually an organic solvent, for example, aromatic solvents, ketone solvents, amide solvents, Alcohol ether solvents, etc.

As said aromatic solvent, benzene, toluene, xylene, etc. are mentioned, for example. Examples of the above-mentioned ketone-based solvent include: acetone, methyl ethyl ketone, methyl isobutyl ketone, 2-heptanone, 4-heptanone, 2-octanone, cyclopentanone, cyclohexanone, ethyl Acetone, etc. Examples of the above-mentioned amide-based solvents include formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, N,N - Dimethylacetamide, 2-pyrrolidone, N-methylpyrrolidone and the like. 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 Butyl ether, propylene glycol monomethyl ether acetate, etc.

In addition, as the solvent in this embodiment, only one of the solvents exemplified above may be used, or two or more of them may be used in any combination and ratio.

＝Reaction Condition＝ The reaction of the said epoxy compound and the said phenolic compound can be performed by a well-known method. The reaction system can be under any conditions of normal pressure, increased pressure, or reduced pressure. In addition, the reaction temperature is usually 80 to 240°C, preferably 100 to 220°C, more preferably 120 to 200°C. Since reaction is easy to progress that reaction temperature is more than the said minimum, it is preferable. Moreover, when reaction temperature is below the said upper limit, a side reaction will not progress easily, and it is preferable from this viewpoint to obtain a high-purity epoxy compound. The reaction time is not particularly limited, but is usually 0.5 to 24 hours, preferably 1 to 22 hours, and more preferably 1.5 to 20 hours. If the reaction time is not more than the above-mentioned upper limit, it is preferable in terms of improving production efficiency, and when it is more than the above-mentioned lower limit, it is preferable in that point that unreacted components can be reduced.

(Molecular weight of epoxy resin (A)) The molecular weight of the epoxy resin (A) is preferably from 2,000 to 300,000, more preferably from 10,000 to 100,000. An epoxy resin layer which has sufficient elasticity and elongation as a molecular weight is more than the said minimum is obtained. On the other hand, if it is below the said upper limit, the coating liquid suitable for efficient film formation can be obtained regardless of the kind of solvent. In addition, molecular weight was measured by the method which used the gel permeation chromatography (GPC), and determined it as the conversion value based on the polystyrene standard.

(Epoxy equivalent of epoxy resin (A)) The epoxy equivalent of the epoxy resin (A) is preferably at least 100 g/eq, more preferably at least 200 g/eq, further preferably at least 300 g/eq, still more preferably at least 500 g/eq. On the other hand, the epoxy equivalent is preferably at most 200,000 g/eq, more preferably at most 150,000 g/eq, further preferably at most 100,000 g/eq, still more preferably at most 50,000 g/eq. If the epoxy equivalent is more than the above-mentioned lower limit, then it is preferable from the viewpoint of the flexibility of the epoxy compound, and if it is below the above-mentioned upper limit, when the composition containing the epoxy compound described below is cured, the ring It is preferable in that the density between crosslinking points between oxygen groups becomes high, and hardening physical properties are easily obtained. In addition, in this invention, "epoxy equivalent" is defined as "the mass of the epoxy compound containing the epoxy group of 1 equivalent", and it can measure based on JISK7236.

2. Isocyanate compound (B) When the epoxy resin composition in this embodiment contains an isocyanate compound (B) as a crosslinking agent, the hardening speed can be accelerated, and optical characteristics, heat resistance, and solvent resistance are favorable. Furthermore, in the present invention, "crosslinking agent" refers to a component that contributes to the crosslinking reaction and/or chain extension reaction between the epoxy groups of the epoxy resin (A).

As the isocyanate compound (B) in this embodiment, for example, methylcyclohexane diisocyanate, hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, dicyclohexylmethane diisocyanate, isophor Aliphatic isocyanates such as ketone diisocyanate, dimer acid diisocyanate, and trimethylhexamethylene diisocyanate; aromatic isocyanates such as toluene diisocyanate, xylylene diisocyanate, and diphenylmethane diisocyanate; free amines acid triisocyanate, etc. Also, isocyanate compounds obtained by reacting the above-exemplified isocyanate compounds with compounds having active hydrogen atoms such as amine groups, hydroxyl groups, carboxyl groups, and water (for example, adducts of isocyanate compounds, isocyanate compounds Biuret, etc.), or tri-pentamers of the above-exemplified isocyanate compounds (for example, isocyanurate of isocyanate compounds, etc.), and the like.

As the isocyanate compound (B) in this embodiment, only one of the isocyanate compounds exemplified above may be used, or two or more of them may be used in any combination and ratio. Among them, a compound having an aliphatic isocyanate as a main skeleton is preferable from the viewpoint of film transparency and weather resistance, and a compound having a hexamethylene diisocyanate as a main skeleton is more preferable.

The content of the isocyanate compound (B) in the present embodiment is preferably 0.1 to 100 parts by mass, more preferably 1 to 80 parts by mass, and still more preferably 5 to 60 parts by mass, based on 100 parts by mass of the epoxy resin (A). share.

3. Other ingredients The epoxy resin composition in this embodiment may contain components other than the above-mentioned epoxy resin (A) and isocyanate compound (B). Examples of the above-mentioned other components include: crosslinking agents other than the above-mentioned isocyanate compound (B), leveling agents, solvents, hardening accelerators (except those corresponding to the above-mentioned crosslinking agents), coupling agents, flame retardants, etc. Agents, antioxidants, light stabilizers, plasticizers, reactive diluents, filler pigments, inorganic fillers, organic fillers, etc. The above-mentioned other components can be used in appropriate combination according to the required physical properties of the epoxy resin composition.

(crosslinking agent) Examples of crosslinking agents other than the above-mentioned isocyanate compound (B) include polyfunctional phenols, amine compounds, acid anhydride compounds, imidazole compounds, amide compounds, cationic polymerization initiators, and organic phosphines. wait.

Examples of the polyfunctional phenols include bisphenols such as bisphenol A, bisphenol F, bisphenol S, bisphenol B, bisphenol AD, bisphenol Z, and tetrabromobisphenol A; 4,4′ -Biphenol, 3,3',5,5'-tetramethyl-4,4'-biphenol and other biphenols; catechol, resorcinol, hydroquinone, dihydroxynaphthalene; And the hydrogen atoms bonded to the aromatic rings of these compounds are substituted by non-interfering substituents such as halogen groups, alkyl groups, aryl groups, ether groups, ester groups, organic substituents including heteroatoms such as sulfur, phosphorus, and silicon wait. Also, novolaks, resols, etc., which are polycondensates of the phenols exemplified above or monofunctional phenols such as phenol, cresol, and alkylphenol, and aldehydes can also be mentioned.

Examples of the above-mentioned amine compounds include: aliphatic primary amines, secondary amines, and tertiary amines; aromatic primary amines, secondary amines, and tertiary amines; cyclic amines; guanidines; urea derivatives, etc., specifically For example, triethylenetetramine, diaminodiphenylmethane, diaminodiphenyl ether, m-xylylenediamine, dicyandiamide, 1,8-diazabicyclo (5,4,0 )-7-undecene, 1,5-diazabicyclo(4,3,0)-5-nonene, dimethylurea, guanidine urea, etc.

As said acid anhydride type compound, the condensation product of phthalic anhydride, hexahydrophthalic anhydride, trimellitic anhydride, maleic anhydride, and an unsaturated compound etc. are mentioned, for example.

Examples of the imidazole-based compounds include: 1-isobutyl-2-methylimidazole, 2-methylimidazole, 1-benzyl-2-methylimidazole, 1-benzyl-2-phenylimidazole , 2-ethyl-4-methylimidazole, 2-phenylimidazole, benzimidazole, etc.

As said amide-type compound, dicyandiamide and its derivative(s), polyamide resin, etc. are mentioned, for example.

The above-mentioned cationic polymerization initiator is one that generates cations by heat or active energy ray irradiation, and examples thereof include aromatic onium salts and the like. Concretely, it includes anion components such as SbF ₆ ^- , BF ₄ ^- , AsF ₆ ^- , PF ₆ ^- , CF ₃ SO ₃ , B(C ₆ F ₅ ) ^4- , and iodine, sulfur, nitrogen, and phosphorus. Compounds of equiatomic aromatic cation components, etc. Among them, diaryliumium salts and triaryliumium salts are preferred.

Examples of the above-mentioned organic phosphines include tributylphosphine, methyldiphenylphosphine, triphenylphosphine, diphenylphosphine, and phenylphosphine, and examples of the phosphonium salt include tetraphenylboronic acid. Tetraphenylphosphonium, tetraphenylphosphonium ethyl triphenyl borate, tetrabutyl phosphonium tetrabutyl borate, etc., as tetraphenyl boron salts, for example: 2-ethyl-4-methylimidazolium tetraphenyl Borate, N-methyl phylloline tetraphenyl borate, etc.

When using multifunctional phenols, amine compounds, and acid anhydride compounds, it is preferable to use them in the following manner: with respect to all epoxy groups in the epoxy resin composition, according to the functional groups in the crosslinking agent (poly The equivalent ratio of the hydroxyl group of the functional phenol, the amine group of the amine compound, or the acid anhydride group of the acid anhydride compound) is in the range of 0.01 to 1.5. When using an imidazole compound, it is preferable to use it in the range of 0.001-10 mass parts with respect to 100 mass parts of all epoxy components. When using an amide compound, it is preferable to use it in the range of 0.001-20 mass % in 100 mass % of epoxy resin compositions. When using a cationic polymerization initiator, it is preferable to use it in the range of 0.001-15 mass parts with respect to 100 mass parts of all epoxy components. When using an organic phosphine, it is preferable to use it in the range of 0.001-20 mass % in 100 mass % of epoxy resin compositions.

(leveling agent) In order to improve the surface appearance when formed into a film, a leveling agent may be added to the epoxy resin composition in this embodiment. If a leveling agent is added, the contact angle of water droplets on the surface of the epoxy resin layer can also be controlled. As a leveling agent, silicone type, polyacrylate type, and perfluoroalkyl type leveling agents, such as a silane coupling agent, are mentioned, for example. As the leveling agent, only one of the above-exemplified ones may be used, or two or more of them may be used in any combination and ratio. Among them, as a leveling agent, it is preferable to use polyether-modified silicone, silicone macromer-modified acrylate, polyether Macromer modified acrylate, silicone-polyether macromer modified acrylate, etc. Furthermore, in terms of optical properties, it is more preferable to use a leveling agent containing a silicone skeleton such as polyether-modified silicone and a polyether skeleton. Also, in order to prevent the film from shrinking during drying, the leveling agent preferably does not contain an acrylic skeleton. The content of the leveling agent in the epoxy resin composition is preferably in the range of 0.01 to 3 parts by mass, more preferably in the range of 0.05 to 2 parts by mass, and further preferably in the range of 0.1 to 1 part by mass relative to 100 parts by mass of the epoxy resin. The range of parts by mass.

(solvent) The epoxy resin composition in this embodiment can add a solvent to adjust the solid content concentration of the epoxy resin composition. As a solvent, what is necessary is just to dissolve an epoxy resin (A), an isocyanate compound (B), and other components normally, and what was mentioned as a solvent used for the said epoxy resin (α) preparation can be used as an example. The solvent is preferably used so that the solid content concentration of the epoxy resin composition is 10 to 90% by mass, more preferably used so that the solid content concentration of the epoxy resin composition is 20 to 80% by mass.

[cured product (epoxy resin layer)] The epoxy resin layer is a cured product obtained by curing the above-mentioned epoxy resin composition. In addition, "hardening" in this invention means hardening an epoxy resin composition intentionally by heat and/or light etc. The degree of hardening can be selected according to the desired physical properties and applications. In the present invention, it is necessary to be completely hardened from the viewpoint that the physical properties of the hardened product do not change even if heat treatment is performed in a subsequent step. Whether the epoxy resin layer is completely cured can be confirmed by measuring the glass transition temperature with a differential scanning calorimeter according to JIS K7121, and confirming it according to the glass transition temperature when the temperature is raised at this time and when the temperature is raised again. In the present invention, the case where the difference (T2-T1) between the glass transition temperature (T2) at the time of reheating and the glass transition temperature (T1) at the time of heating is within 3° C. is regarded as complete hardening. T2-T1 is preferably within 2°C, more preferably within 1°C.

The epoxy resin layer is preferably such that the contact angles of water droplets on both surfaces are 84 degrees or less, so even if a functional layer or wiring is provided in a subsequent step, it is not easy to cause problems such as poor adhesion. From this viewpoint, the water droplet contact angle of both surfaces of the epoxy resin layer is more preferably 80 degrees or less. Furthermore, the water droplet contact angle was measured by the method described in the examples.

The thickness of the epoxy resin layer is preferably from 1 to 1000 μm, more preferably from 5 to 500 μm, and still more preferably from 10 to 300 μm. When the thickness of the epoxy resin layer is within the above-mentioned range, it has moderate handleability and bending resistance, so it is suitable for use in electronic components.

The glass transition temperature of the epoxy resin layer is preferably at least 100°C, more preferably at least 110°C, further preferably at least 115°C, still more preferably at least 120°C, particularly preferably at least 126°C. The heat resistance of an epoxy resin layer becomes favorable that a glass transition temperature is the said range. In particular, when the glass transition temperature is 126° C. or higher, bending resistance also tends to become favorable. The upper limit of the glass transition temperature is not particularly limited, but is preferably 220°C or lower, more preferably 190°C or lower, from the viewpoint of film flexibility.

When an epoxy resin layer is used for electronic components, such as a display, it is preferable that transparency is high. From this point of view, the light transmittance of the epoxy resin layer at 400 nm is preferably at least 75%, more preferably at least 80%, further preferably at least 85%, and even more preferably at least 88%. In addition, the light transmittance of the epoxy resin layer at 650 nm is preferably at least 80%, more preferably at least 85%, and still more preferably at least 90%. Moreover, the haze of the epoxy resin layer is preferably 5% or less, more preferably 3% or less, and still more preferably 1% or less. Moreover, the yellowness (YI) of an epoxy resin layer becomes like this. Preferably it is 5 or less, More preferably, it is 3 or less, More preferably, it is 1 or less. In addition, light transmittance and haze are measured by the method described in an Example.

When the epoxy resin layer is used for electronic components such as flexible displays, it is preferable to have bending resistance. The bending resistance is evaluated by the minimum bending radius R that does not cause cracks and creases in repeated bending tests, for example, 200,000 times. The R of the epoxy resin layer is preferably at most 3 mm, more preferably at most 2 mm, further preferably at most 1.5 mm, even more preferably at most 1 mm. When the maximum bending radius R is within the above range, durability against bending when used in electronic components such as flexible displays is good.

＜Release film＞ As the release film in the present embodiment, a sheet-like one made of paper, resin, metal, or the like may, for example, be mentioned. Among them, paper or resin is preferable in terms of low price, easy processing, and easy disposal and recycling, and resin is more preferable in terms of transparency.

As paper, for example, high-grade paper, kraft paper, cellophane, parchment, and super-calendered kraft paper whose surface is treated with silicone coating can be used.

As the resin film, for example, a film mainly composed of polyolefin such as polyethylene and polypropylene, polyester such as polyethylene terephthalate and polyethylene naphthalate, polyimide, or polycarbonate can be used. . The peeling strength can be adjusted by coating silicone resin release agent etc. on the surface. Among the above-mentioned resin films, a resin film containing polyester as a main component is preferable in terms of appearance, ease of processing, durability, heat resistance, cost, and the like. As long as it does not deviate from the spirit of the present invention, the above-mentioned resin film may be composed of a single layer or a multilayer structure of two or more layers. Furthermore, "main component resin" refers to the resin with the largest content among the resins constituting the base material, specifically, it refers to the resin accounting for 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, and furthermore More than 90% by mass (including 100% by mass) of resin is preferable.

The above-mentioned polyester is preferably obtained by polycondensing an aromatic dicarboxylic acid and an aliphatic diol. The polyester may be a polyester comprising an aromatic dicarboxylic acid and an aliphatic diol, or may be a copolyester obtained by further copolymerizing with one or more other components. Examples of aromatic dicarboxylic acids include terephthalic acid and 2,6-naphthalene dicarboxylic acid, and examples of aliphatic diols include ethylene glycol, diethylene glycol, and 1,4-cyclohexyl alkanedimethanol, etc. On the other hand, examples of dicarboxylic acids used as other components of the copolyester include isophthalic acid, phthalic acid, terephthalic acid, 2,6-naphthalene dicarboxylic acid, and sebacic acid. As a diol component, ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, 1, 4- cyclohexanedimethanol, neopentyl glycol, etc. are mentioned, for example. In addition, hydroxycarboxylic acids such as p-hydroxybenzoic acid can also be used. Examples of typical polyesters include polyethylene terephthalate obtained by polycondensing terephthalic acid and ethylene glycol, and polyethylene naphthalate obtained by polycondensing 2,6-naphthalene dicarboxylic acid and ethylene glycol. Ethylene formate, etc. The polyester film may be an unstretched film or a stretched film, and is preferably a stretched film, more preferably a biaxially stretched film, from the viewpoint of mechanical strength. In addition, surface treatments such as corona treatment and plasma treatment may be given to the polyester film in advance.

In addition, the release film may have a structure that further includes a release layer as the outermost layer on the side in contact with the epoxy resin layer in addition to the resin film described above. Since the release film further includes the release layer in addition to the resin film, the peelability between the epoxy resin layer and the release film becomes favorable.

The composition of the release layer is not particularly limited, and may contain silicone compounds, fluorine compounds, waxes, surfactants, and the like. It is preferable to use a silicone compound in terms of a good balance between price and releasability. Furthermore, in order to adjust the releasability of a release layer, a peel control agent can be used together.

Commercially available products that can be used as a release film including a resin film and a release layer include: "Purex A31" manufactured by Toyobo Film Solution Co., Ltd.; "MRF-38" manufactured by Mitsubishi Chemical Corporation. ", "MRF-75"; "SP-PET (registered trademark)" manufactured by Mitsui Chemicals Tohcello Co., Ltd.

＜＜Manufacturing method of laminate (1)＞＞ The laminate (1) in this embodiment is obtained by applying the coating liquid containing the said epoxy resin composition to a release film and hardening it.

The method of applying a coating liquid to a release film may be a known method. Examples of such coating methods include chipping wheel coating, gravure coating, reverse coating, blade coating, dip coating, spray coating, air knife coating, and spin coating. Coating method, roll coating method, printing method, inclined plate coating method, curtain coating method, die coating method, casting method, rod coating method, extrusion coating method, etc.

The hardening conditions of the coating liquid can be appropriately adjusted according to the ingredients and the compounding amount in the composition, and the conditions of heating at 80-200°C for 1-180 minutes are preferred. In terms of reducing poor hardening, the heating is preferably carried out by two-stage treatment, that is, the first heating at 80-160°C for 1-30 minutes, and the heating at a temperature 40-120°C higher than the first heating temperature. The second heating is carried out at 120-200°C for 1-150 minutes.

＜＜Epoxy film＞＞ An epoxy film is obtained by peeling the release film from the laminate (1) in the present invention. That is, the epoxy film according to one embodiment of the present invention includes an epoxy resin containing an epoxy resin (A) and an isocyanate compound (B), and the epoxy resin (A) does not substantially contain a trifunctional or higher epoxy resin. The composition, measured by DSC, is heated from 20°C to 250°C at 10°C/min, then cooled to 0°C at 10°C/min, and then reheated at 10°C/min from 0°C to 250°C When measuring the above-mentioned epoxy resin layer, the difference (T2-T1) between the glass transition temperature (T2) and the glass transition temperature (T1) when the temperature is raised again is within 3°C. As mentioned above, the contact angles of water droplets on both surfaces of the epoxy film of the present invention are 84 degrees or less, so even if a functional layer or wiring is provided in a subsequent step, problems such as poor adhesion are not likely to occur. Furthermore, the measurement method of the water droplet contact angle is as described in the examples.

When a functional layer is provided on at least one side of the epoxy film, the functional layer may, for example, be a hard coat layer, an antistatic layer, an antiglare layer, a low reflection layer, an antireflection layer, or an antifouling layer. The functional layer may be a single layer having multiple functions as described above, or two or more layers having each function may be laminated.

(hard coat) When a hard coat layer is provided on at least one surface of an epoxy film, damage resistance, chemical resistance, etc. can be provided to the surface of an epoxy film. The hard coat layer is preferably formed of a curable resin composition. The above-mentioned curable resin composition is not particularly limited, for example, as long as it is cured by irradiation with energy rays such as electron beams, radiation, or ultraviolet rays, or cured by heating. From the viewpoint of molding time and productivity, Preferable is an ultraviolet curable resin composition.

Preferred examples of the curable resin constituting the curable resin composition include acrylate compounds, urethane acrylate compounds, epoxy acrylate compounds, carboxyl-modified epoxy acrylate compounds, polyester Acrylate compounds, copolymerized acrylates, alicyclic epoxy resins, glycidyl ether epoxy resins, vinyl ether compounds, oxetane compounds, etc. These hardening resins can be used individually by 1 type or in combination of 2 or more types. Among them, examples of curable resins that impart excellent surface hardness include radically polymerizable curable compounds such as polyfunctional acrylate compounds, polyfunctional urethane acrylate compounds, and polyfunctional epoxy acrylate compounds. ; and thermally polymerizable hardening compounds such as alkoxysilanes or alkylalkoxysilanes.

Furthermore, the above-mentioned curable resin composition may be an organic-inorganic hybrid curable resin composition containing an inorganic component in the above-mentioned curable resin. Examples of the above-mentioned organic-inorganic hybrid curable resin composition include curable resin compositions containing an inorganic component having a reactive functional group in the above-mentioned curable resin. Using such an inorganic component with a reactive functional group, for example, copolymerize and cross-link the inorganic component with a radically polymerizable monomer, thereby combining with an organic-inorganic composite curable resin containing only inorganic components in the organic binder Compared with materials, it is not easy to produce hardening shrinkage, and can exhibit higher surface hardness. Furthermore, an organic-inorganic hybrid curable resin composition containing ultraviolet-ray reactive colloidal silica as an inorganic component having a reactive functional group is also preferable from the viewpoint of reducing curing shrinkage.

The curable resin composition for forming the hard coat layer may contain a leveling agent, a photopolymerization initiator, a refractive index adjusting component, a lubricant, an antioxidant, an ultraviolet absorber, an antistatic agent, an antistatic agent, and Combustion agent, filler, glass fiber and silicon dioxide, etc.

＜＜Wound body＞＞ The laminate (1) and the epoxy film in the present invention can be wound into a roll by being wound around a core. The length of the laminate (1) and the epoxy film is not particularly limited, but is preferably at least 5 m, more preferably at least 10 m, and still more preferably at least 50 m from the viewpoint of workability in the subsequent steps. Also, the length of the laminate (1) and the epoxy film is preferably 10000 m or less.

Furthermore, the core system refers to a cylindrical core used for winding up of the film. The material of the core is not particularly limited, for example, paper, resin impregnated paper, acrylonitrile-butadiene-styrene copolymer (ABS resin), FRP (Fiber Reinforced Plastic, fiber reinforced plastic), phenolic resin, Resins containing inorganic substances. Among them, it is preferable to include acrylonitrile-butadiene-styrene copolymer (ABS resin), Resins such as FRP, phenolic resins, and resins containing inorganic substances. In the case where the material of the core is paper, desired characteristics are easily obtained by coating the surface thereof with, inter alia, resin or the like. Furthermore, the core is also preferably a resin-impregnated paper tube from the viewpoint of surface smoothness.

＜＜Application＞＞ The laminate and epoxy film of the present invention can be suitably used for electronic components such as displays and printed wiring boards because the epoxy resin layer has a high water droplet contact angle on both surfaces and has good adhesion to functional layers or wiring. Among them, particularly preferred is a display. [Example]

Next, the present invention is described in more detail by examples. However, the present invention is not limited to the Examples described below.

＜Material＞ Materials used in Examples and Comparative Examples are as follows.

[epoxy resin] (A-1): A bisphenol A type epoxy resin ("YL7852BT40" manufactured by Mitsubishi Chemical Corporation, weight average molecular weight 49,280, epoxy equivalent 6,740 g/eq) was used. (A-2): A bisphenol A novolac type epoxy resin ("jER157S65" manufactured by Mitsubishi Chemical Corporation, epoxy equivalent 208 g/eq) was used.

[Crosslinking agent] (B-1): A polyisocyanate ("Coronate 2715" manufactured by Tosoh Corporation) mainly composed of hexamethylene diisocyanate was used. (B-2): 1-benzyl-2-phenylimidazole ("Curezol 1B2PZ" manufactured by Shikoku Chemicals Co., Ltd.) was used. (B-3): 2-Ethyl-4(5)-methylimidazole ("EMI-24" manufactured by Mitsubishi Chemical Corporation) was used.

[additive] (C-1): A leveling agent ("BYK-3566" manufactured by BYK-Chemie Japan Co., Ltd., silicone and polyether macromonomer-modified acrylate) was used. (C-2): A leveling agent ("BYK-333" manufactured by BYK-Chemie Japan Co., Ltd., polyether-modified silicone) was used.

[solvent] (D-1): Toluene (D-2): Methyl ethyl ketone

[Release film] "SP-PET (registered trademark) O3-BU" (100 μm) manufactured by Mitsui Chemicals Tohcello Co., Ltd. was used as a release film including a polyester film and a silicone-based release layer.

＜Making of laminated body＞ [Example 1] Epoxy resin (A-1), crosslinking agents (B-1) and (B-2), and solvents (D-1) and (D-2) were mixed in the ratio described in Table 1 to prepare a coating liquid. Use an applicator to apply the coating liquid on the release film, heat it once at 80°C for 2 minutes using a constant temperature dryer, and heat it at 180°C for 5 minutes for a second time to harden, and cool it naturally to room temperature (25 °C), thereby forming an epoxy resin layer to obtain the laminate of Example 1. The resulting epoxy resin layer had a thickness of 25 μm. The obtained epoxy resin layer was peeled from the release film, and the glass transition temperature was measured. The glass transition temperature was 130°C, and the glass transition temperature at the time of reheating was 130°C, so complete hardening was confirmed.

[Example 2] Except having added the additive (C-1) at the ratio described in Table 1, the epoxy resin layer was formed on the same conditions as Example 1, and the laminated body of Example 2 was obtained. The resulting epoxy resin layer had a thickness of 25 μm. The obtained epoxy resin layer was peeled from the release film, and the glass transition temperature was measured. The glass transition temperature was 128°C, and the glass transition temperature at the time of reheating was 129°C, so complete hardening was confirmed.

[Example 3] Except having added the additive (C-2) at the ratio described in Table 1, the epoxy resin layer was formed on the same conditions as Example 1, and the laminated body of Example 3 was obtained. The resulting epoxy resin layer had a thickness of 25 μm. The obtained epoxy resin layer was peeled from the release film, and the glass transition temperature was measured. The glass transition temperature was 128°C, and the glass transition temperature at the time of reheating was 129°C, so complete hardening was confirmed.

[Example 4] Except having prepared in the ratio described in Table 1, the epoxy resin layer was formed on the same conditions as Example 3, and the laminated body of Example 4 was obtained. The resulting epoxy resin layer had a thickness of 25 μm. The obtained epoxy resin layer was peeled from the release film, and the glass transition temperature was measured. The glass transition temperature was 125°C, and the glass transition temperature at the time of reheating was 125°C, so complete hardening was confirmed.

[Comparative example 1] Epoxy resins (A-1) and (A-2), crosslinking agent (B-3), solvents (D-1) and (D-2) were mixed at the ratios described in Table 1 to prepare coating liquids. Use an applicator to apply the coating liquid on the release film, heat it once at 150°C for 30 minutes with a constant temperature dryer, and heat it again at 170°C for 60 minutes to harden, and cool it to room temperature naturally. This formed an epoxy resin layer, and the laminated body of the comparative example 1 was obtained. The resulting epoxy resin layer had a thickness of 25 μm. The obtained epoxy resin layer was peeled from the release film, and the glass transition temperature was measured. The glass transition temperature was 104°C, and the glass transition temperature when the temperature was raised again was 103°C, so complete hardening was confirmed.

[Comparative example 2] Epoxy resins (A-1), (A-2), crosslinking agent (B-3), solvents (D-1) and (D-2) were mixed at the ratios listed in Table 1 to prepare coating liquids. Use an applicator to apply the coating liquid on the release film, heat it once at 80°C for 2 minutes using a constant temperature dryer, and heat it at 180°C for 5 minutes for a second time to harden, and cool it naturally to room temperature (25 °C), thereby forming an epoxy resin layer, and obtaining a laminate of Comparative Example 2. The resulting epoxy resin layer had a thickness of 25 μm. The obtained epoxy resin layer was peeled from the release film, and the glass transition temperature was measured. The glass transition temperature was 96°C, and the glass transition temperature when the temperature was raised again was 104°C, and incomplete hardening was confirmed.

[Comparative example 3] Mix epoxy resins (A-1), (A-2), crosslinking agents (B-1), (B-3), solvents (D-1) and (D-2) in the ratios listed in Table 1, A coating liquid is prepared. Use an applicator to apply the coating liquid on the release film, heat it once at 80°C for 2 minutes using a constant temperature dryer, and heat it at 180°C for 5 minutes for a second time to harden, and cool it naturally to room temperature (25 °C), thereby forming an epoxy resin layer to obtain the laminate of Example 1. The resulting epoxy resin layer had a thickness of 25 μm. The obtained epoxy resin layer was peeled from the release film, and the glass transition temperature was measured. The glass transition temperature was 120°C, and the glass transition temperature when the temperature was raised again was 125°C, and incomplete hardening was confirmed.

＜Evaluation items＞ (1) Water droplet contact angle The release film was removed from the laminate, and the water drop contact angle of the epoxy resin layer was measured using a contact angle meter "DropMaster 500" manufactured by Kyowa Interface Science Co., Ltd. Ion-exchanged water was used for the measurement. The measurement temperature was 25°C, and the drop volume of ion-exchanged water was 2 μL, and the water droplet contact angle after the droplet contacted for 1 second was evaluated. Three places of the epoxy resin layer were measured, and the average value was calculated. Furthermore, in Table 1, the surface on the side not in contact with the release film is marked as the "front" of the epoxy resin layer, and the surface on the side in contact with the release film is marked as the "back" of the epoxy resin layer.

(2) degree of hardening The curing degree of the epoxy resin layer is measured based on the "midpoint glass transition temperature: Tmg" described in JIS K7121 "Measuring method of transition temperature of plastics". Specifically, using a differential scanning calorimeter "DSC8500" manufactured by PerkinElmer Japan Co., Ltd., the temperature was raised from 20°C to 250°C at 10°C/min, and then cooled to 0°C at 10°C/min. The measurement was performed by reheating at 10°C/min from °C to 250°C. When the glass transition temperature at the reheating time is not higher than the glass transition temperature at the heating time by more than 3°C, it is considered to be completely hardened.

(3) Light transmittance and haze The light transmittance and haze of the epoxy resin layer at 400 nm and 650 nm were measured using a haze meter "NDH 7000II" manufactured by Nippon Denshoku Industries Co., Ltd. The measurement was performed in accordance with JIS (total light transmittance: JIS K 7361-1, haze: JIS K 7136).

(4) Yellowness (YI value) The yellowness (YI value) of the epoxy resin layer was measured using a spectrocolorimeter "SD6000" manufactured by Nippon Denshoku Industries Co., Ltd. according to ASTM E313. The light source is C, and the viewing angle is 2°.

(5) Bending resistance (R) Using a bending tester (manufactured by Yuasa System Co., Ltd., DLDMLH-FS), the epoxy resin layer was subjected to a bending test of 200,000 times, and the minimum bending radius R without cracks and creases was evaluated. In addition, since the epoxy resin layer of Examples 1-4 did not produce cracks and creases even if R=1 mm, it was recorded as "1 mm or less" in Table 1.

[Table 1] Table 1 Example 1 Example 2 Example 3 Example 4 Comparative example 1 Comparative example 2 Comparative example 3 epoxy resin (A-1) [parts by mass] 100 100 100 100 100 100 100 (A-2) [parts by mass] - - - - 2.1 2.1 2.1 crosslinking agent (B-1) [parts by mass] 30 30 30 30 - - 30 (B-2) [parts by mass] 0.006 0.006 0.004 0.004 - - (B-3) [parts by mass] - - - - 0.2 0.2 0.2 additive (C-1) [parts by mass] - 0.4 - - - - - (C-2) [parts by mass] - - 0.4 0.33 - - - solvent (D-1) [parts by mass] 27 27 27 33 6 6 6 (D-2) [parts by mass] 33 33 33 62 13 13 13 Hardness T2 ℃ 130 129 129 129 104 104 125 T1 ℃ 130 128 128 128 103 96 120 T2-T1 ℃ 0 1 1 1 1 8 5 water droplet contact angle surface [Spend] 80 80 81 76 79 83 80 Back (release side) [Spend] 82 60 75 80 112 93 85 400 nm transmittance [%] 89.0 88.9 89.5 89.3 87.9 88.6 89.0 650 nm transmittance [%] 90.1 90.8 90.6 90.6 90.4 90.2 90.4 Haze [%] 0.80 0.8 0.6 0.6 1.8 0.9 0.8 YI value - 0.6 0.6 0.6 0.6 0.7 0.7 0.6 R - 1 mm or less 1 mm or less 1 mm or less 1 mm or less 2.0 mm 2.0 mm 3.0 mm

From Examples 1 to 4, it was confirmed that when the epoxy resin composition contained the isocyanate compound (B) as a crosslinking agent, the time required for curing became short and the productivity was good. Moreover, it was confirmed that the water droplet contact angle of both surfaces of the epoxy resin layer of Example 1-Example 4 was 84 degrees or less, and it had moderate wettability. Furthermore, from Examples 2-4, it was confirmed that the water droplet contact angle can be adjusted by an additive (leveling agent). This is considered to be due to segregation of the additive (leveling agent) at the interface between the epoxy resin layer and the release film. By controlling the water droplet contact angle to 84 degrees or less, the required wettability can be expected to improve the adhesion in the subsequent steps. On the other hand, in Comparative Example 1, it required a long time of heating until it was completely cured, so the productivity was poor. Also, since the time required for curing is long, the water droplet contact angle on the back side of the epoxy resin layer (release film side) becomes high, and as a result, the adaptability to the subsequent steps is impaired. Although the curing time of Comparative Example 2 is the same as that of Example 1, but it contains a trifunctional epoxy resin, the result is that the curing reaction is very slow, and it is far from being fully cured. It can be seen that Comparative Example 3 is a case where isocyanate was further used in combination with Comparative Example 2, and although the curing reaction proceeded a little, it did not reach the level of complete curing. From the above situation, it can be seen that the epoxy resin with more than three functionalities greatly affects the curing reaction speed. In addition, since the glass transition temperature of Comparative Examples 1 to 3 did not reach 126°C, which was lower than that of Examples, the resulting R value (evaluation of bending resistance) was worse than that of Examples.

Claims (16)

A laminate comprising at least an epoxy resin layer formed by curing an epoxy resin composition containing an epoxy resin (A) and an isocyanate compound (B), and a release film, and The epoxy resin (A) does not substantially contain a trifunctional or higher epoxy resin, As measured by DSC, the temperature was raised from 20°C to 250°C at 10°C/min, and then the temperature was lowered to 0°C at 10°C/min, and then the temperature was raised again from 0°C to 250°C at 10°C/min to determine the above For the epoxy resin layer, the difference (T2-T1) between the glass transition temperature (T2) and the glass transition temperature (T1) at the time of heating up should be within 3°C. The laminate according to claim 1, wherein the above-mentioned epoxy resin (A) is a resin obtained by reacting an epoxy compound and a phenolic compound. The laminate according to claim 2, wherein the above-mentioned epoxy compound is a compound having two or less epoxy groups in the molecule. The laminate according to claim 2 or 3, wherein the above-mentioned phenolic compound is a compound having two or more hydroxyl groups bonded to an aromatic ring. The laminate according to any one of claims 1 to 4, wherein the epoxy resin (A) has a molecular weight of 2,000 to 300,000. The laminate according to any one of Claims 1 to 5, wherein the above-mentioned isocyanate compound (B) is a compound having an aliphatic isocyanate as a main skeleton. The laminate according to any one of claims 1 to 6, wherein the epoxy resin composition contains a leveling agent. The laminate according to claim 7, wherein the leveling agent includes a silicone skeleton and a polyether skeleton. The laminate according to claim 7 or 8, wherein the leveling agent does not contain an acrylic skeleton. The laminate according to any one of claims 1 to 9, wherein the glass transition temperature of the epoxy resin layer is 100°C or higher. A method for manufacturing a laminate according to any one of Claims 1 to 10, which is performed by a first heat treatment at 80°C to 160°C and a second heat treatment at 120 to 200°C that is 40 to 120°C higher than the first heat treatment temperature Heat treatment hardens the above-mentioned epoxy resin composition. An epoxy film comprising the above-mentioned epoxy resin composition containing epoxy resin (A) and isocyanate compound (B), and the water droplet contact angles on both surfaces are 84 degrees or less. The epoxy film according to claim 12, which has a functional layer on at least one side. A wound body formed by winding the laminate according to any one of claims 1 to 10 or the epoxy film according to claim 12 or 13 on a core. The laminate according to any one of claims 1 to 10, which is used for a display. The epoxy film according to claim 12 or 13, which is used for a display.