TWI876401B - Energy ray curing film-like transparent adhesive, device containing the same and method for manufacturing the device - Google Patents

Abstract

The present invention is an energy ray-curing film-like transparent adhesive, a device containing the film-like transparent adhesive, and a method for manufacturing a device using the film-like transparent adhesive. The energy ray-curing film-like transparent adhesive contains an epoxy resin, a phenoxy resin, and a photo-cation polymerization initiator containing antimony in the cationic part.

Description

Energy ray curing film-like transparent adhesive, device containing the same and method for manufacturing the device

The present invention relates to an energy ray-curable film-shaped transparent adhesive, a device containing the same and a method for manufacturing the device.

Image sensors (imaging elements) such as CMOS image sensors and CCD image sensors are built into digital still cameras or digital video recorders. Image sensors convert incident light into electrical signals by photoelectric conversion through photodiodes, and form digital images through signal processing. Color filters, microlenses, etc. are configured on the surface of the photodiode as needed, and a transparent protective film such as a glass plate is usually configured on the surface of the laminate. This transparent protective film is fixed by a film-like adhesive, etc. The adhesive used for bonding and fixing the transparent protective film of the image sensor requires sufficient transparency to allow light to pass through. On the other hand, in image display devices, there are also situations where functional elements (organic electroluminescent (organic EL) elements, liquid crystal panels, micro-light-emitting diodes (micro-LEDs), semiconductor elements such as transistors, etc.) are arranged on a supporting substrate, and functional layers (protective layers, gas barrier layers (sealing layers), hard coating layers, etc.) are arranged on the surfaces of the functional elements. There are situations where sufficient transparency is also required for adhesives used for bonding and fixing such functional elements and functional layers. Film adhesives themselves are known to have various compositions and are widely used in the manufacture of electronic equipment or their components, etc., and are not limited to image sensors or image display devices. For example, in the process of manufacturing semiconductor chips, film adhesives are used as die bonding films. Patent document 1 discloses a sheet adhesive containing a phenoxy resin having a glass transition temperature of 110°C or higher, a multifunctional epoxy resin, and a photocatalytic polymerization initiator. In a specific embodiment, 4-(phenylthio)phenyl diphenyl chromium hexafluorophosphate is used as the photocatalytic polymerization initiator. The sheet adhesive is considered to have excellent shape stability under high temperature conditions. Patent document 2 discloses an adhesive having active energy ray curability, wherein the X value calculated from the a ^* value and b ^* value of the adhesive according to the CIE1976L ^* a ^* b ^* colorimetric system is set to a specific range, and the color difference ΔE ^* _a before and after curing according to the above colorimetric system is set to a specific range. The adhesive contains a dye whose color disappears due to irradiation with active energy rays and a photoinitiator, and further contains a (meth)acrylate polymer, a crosslinking agent, and an active energy ray curable component. It is believed that the adhesive can easily confirm the curing caused by irradiation with active energy rays. Patent document 3 discloses an organic electroluminescent element sealant, which contains 100 parts by mass of a bisphenol-type epoxy resin as a photo-cationic polymerizable compound, and contains 0.1 to 100 parts by mass of a specific cobalt borate salt as a photo-cationic polymerizer. The sealant is believed to exhibit excellent photocurability and is suitable for sealing electroluminescent elements. [Prior art document] [Patent document]

[Patent Document 1] International Publication No. 2020/196240 [Patent Document 2] Japanese Patent Application No. 2020-26491 [Patent Document 1] Japanese Patent No. 4933751

[The problem that the invention wants to solve]

Among functional components, many have low heat resistance. In order to avoid damage to the components in the manufacture of devices containing such low heat resistance components, a method of manufacturing without heat treatment is adopted. In the manufacture of such devices, as adhesives, most use energy ray-curing film adhesives that can cure in a low temperature range from room temperature to near room temperature. However, compared with liquid adhesives, film adhesives have lower molecular mobility, so the reactivity of the curing components tends to be poor in the low temperature range. In order for film adhesives to cure efficiently in the low temperature range, it is necessary to increase the amount of energy ray exposure compared to liquid adhesives. For example, Patent Document 1 discloses in its specific implementation that, in order to cure the sheet adhesive, ultraviolet (UV) irradiation of 2000 mJ/cm ² is performed, and further heating is performed at 100°C. In addition, Patent Document 2 discloses in its specific implementation that, by the irradiation amount of 2000 mJ/cm ² , the curing of the adhesive layer is substantially completed. In addition, Patent Document 3 discloses in its specific implementation that, in order to cure the sealing material, UV irradiation of 2000 mJ/cm ² and aging heating at 80°C are performed. On the other hand, if the irradiation amount of energy rays increases, even if heating is not performed, heat generation will occur as a side reaction accompanying the curing reaction, and as a result, there is a situation where the functional element is exposed to high temperature. In this case, problems such as poor reliability or decreased transparency caused by the deterioration of the adhesive's own bonding strength are likely to occur. Therefore, a highly reactive film-like transparent adhesive that can be cured by a relatively small amount of energy radiation and whose bonding strength is not easily reduced at high temperatures is desired. In addition, considering that some devices will be placed in a high-temperature environment during use, or some devices themselves will become high temperature due to heat generated from the inside (for example, vehicle-mounted devices, etc.), therefore, from the perspective of improving the reliability of devices in such environments, an adhesive whose bonding strength is not easily reduced at high temperatures is also required. Generally speaking, fillers are mostly added to adhesives to improve bonding strength. By adding fillers, the bonding reliability of the adhesive can be improved. However, the addition of fillers will reduce the transparency of the adhesive. Therefore, when adding fillers, there is a so-called trade-off relationship between the reliability improvement and the transparency of the adhesive. A film-like transparent adhesive that can achieve high bonding reliability even when adding fillers is desired.

The subject of the present invention is to provide an energy-ray-curing film-like transparent adhesive that can be cured with a relatively small amount of energy-ray irradiation and exert sufficient bonding strength, has excellent transparency after curing, and is not easy to reduce bonding strength at high temperatures. In addition, the subject of the present invention is to provide a device containing the above-mentioned energy-ray-curing film-like transparent adhesive and a manufacturing method of the device using the above-mentioned energy-ray-curing film-like transparent adhesive. [Technical means to solve the problem]

The above-mentioned problems of the present invention are solved by the following means. 〔1〕 An energy-ray-curing film-like transparent adhesive, which contains: an epoxy resin, a phenoxy resin, and a photo-cationic polymerization initiator containing antimony in the anionic part. 〔2〕 The energy-ray-curing film-like transparent adhesive described in〔1〕, wherein the glass transition temperature of the above-mentioned phenoxy resin is 80 to 120℃. 〔3〕 The energy-ray-curing film-like transparent adhesive described in〔1〕 or〔2〕, wherein the glass transition temperature of the cured product of the above-mentioned energy-ray-curing film-like transparent adhesive is above 80℃. [4] The energy-ray-curing film-like transparent adhesive as described in any one of [1] to [3], wherein the parallel light transmittance of the cured product of the energy-ray-curing film-like transparent adhesive is 80% or more. [5] The energy-ray-curing film-like transparent adhesive as described in any one of [1] to [4], wherein the storage elastic modulus of the cured product of the energy-ray-curing film-like transparent adhesive at room temperature is 1.0 GPa or more. [6] The energy-ray-curing film-like transparent adhesive as described in any one of [1] to [5], wherein the epoxy resin has a hydrogenated bisphenol structure or a bisphenol structure. [7] The energy-ray-curing film-like transparent adhesive described in any one of [1] to [6], which contains a silane coupling agent. [8] The energy-ray-curing film-like transparent adhesive described in any one of [1] to [7], which contains a curing delay agent. [9] The energy-ray-curing film-like transparent adhesive described in any one of [1] to [8], which contains a filler. [10] A device, which includes a structure in which a component is bonded using the energy-ray-curing film-like transparent adhesive described in any one of [1] to [9]. [11] A method for manufacturing a device, which includes bonding a component using the energy-ray-curing film-like transparent adhesive described in any one of [1] to [9].

In the present invention, the numerical range represented by "～" means a range including the numerical values before and after "～" as the lower limit and the upper limit. [Effects of the invention]

The energy-ray-curing film-shaped transparent adhesive of the present invention can be cured with a relatively small amount of energy-ray irradiation and exert sufficient bonding strength, has high transparency, and is not easily reduced in bonding strength at high temperatures. In addition, even if the energy-ray-curing film-shaped transparent adhesive of the present invention is used as an adhesive for components with low heat resistance, it can suppress damage to the components and further improve the bonding reliability of the obtained device.

[Energy ray-curing film-like transparent adhesive] The energy ray-curing film-like transparent adhesive of the present invention (hereinafter, also referred to as "the film-like adhesive of the present invention") contains an epoxy resin, a phenoxy resin, and a photo-cationic polymerization initiator containing antimony in the cationic part. The film-like adhesive of the present invention is in a state before curing, that is, in the state of the B stage, and is cured by energy ray irradiation to exert bonding strength with the adherend. Therefore, the film-like adhesive of the present invention is a film composed of a curable composition. The film-like adhesive of the present invention can be used for bonding components of a device or for sealing purposes. As devices, there can be listed: digital still cameras, digital video cameras, organic EL devices, liquid crystal panel devices, micro LED devices, smart phones, computers, televisions, etc. The film adhesive of the present invention is particularly suitable for bonding or sealing components of optical products that require high transparency (for example, components of organic EL devices, liquid crystal panels, micro LED devices, etc. (for example, lenses, transparent protective films, glass substrates, functional elements and functional layers described below, laminates of the same, etc.)). As energy rays, there can be listed light such as ultraviolet rays (UV) or ionizing radiation such as electron beams. The energy ray is preferably ultraviolet rays. The film adhesive of the present invention is one that does not use a thermal polymerization initiator.

The components contained in the film adhesive of the present invention are described.

(Epoxy resin) The film adhesive of the present invention contains at least one epoxy resin. The epoxy resin may be any resin having an epoxy group, and any epoxy resin that can be used for an adhesive can be widely used. An epoxy resin is one in which an epoxy group reacts with a reactive group of another component or epoxy groups undergo ring-opening polymerization to form a cross-linked structure in a resin composition. In the present invention, the epoxy resin refers to an epoxy equivalent of 3000 g/eq or less. Furthermore, in the present invention, the epoxy equivalent refers to the number of grams (g/eq) of a resin containing 1 gram equivalent of an epoxy group. The epoxy equivalent of the epoxy resin is preferably 100 to 3000 g/eq, more preferably 180 to 1500 g/eq. When the epoxy resin has an alicyclic structure, the epoxy equivalent is preferably larger. For example, it is preferably set to 200 g/eq or more, more preferably 200 to 3000 g/eq, and further preferably 200 to 1500 g/eq. On the contrary, when the epoxy resin does not have an alicyclic structure, the epoxy equivalent can be further reduced. For example, it is preferably less than 200 g/eq, more preferably 100 to 195 g/eq, further preferably 120 to 195 g/eq, and further preferably 130 to 195 g/eq. From the perspective of improving the softness of the cured product of the film adhesive of the present invention, an epoxy resin having an alicyclic structure and a smaller epoxy equivalent (e.g., an epoxy resin having an epoxy equivalent of 500 g/eq or less, preferably an epoxy resin having an epoxy equivalent of 300 g/eq or less) and an epoxy resin having an alicyclic structure and a larger epoxy equivalent (e.g., an epoxy resin having an epoxy equivalent of 600 to 1300 g/eq, preferably an epoxy resin having an epoxy equivalent of 900 to 1300 g/eq) can also be used in combination.

As the skeleton of epoxy resin, there are: phenol novolac type, o-cresol novolac type, cresol novolac type, dicyclopentadiene type, biphenyl type, fluorene bisphenol type, trisphenol Type, naphthol type, naphthalene diol type, triphenylmethane type, tetraphenyl type, bisphenol A type, bisphenol F type, bisphenol AD type, bisphenol S type, trihydroxymethylmethane type, etc. Among them, from the viewpoint that the crystallinity of the resin is low and a film-like adhesive with good appearance can be obtained, the triphenylmethane type, bisphenol A type, cresol novolac type, and o-cresol novolac type are preferred. These can be used alone or in combination of two or more. The above-mentioned epoxy resin is preferably an epoxy resin having a bisphenol structure. Furthermore, the epoxy resin is preferably an epoxy resin having an alicyclic structure, more preferably a hydrogenated bisphenol type epoxy resin (an epoxy resin having a hydrogenated bisphenol structure), and more preferably a hydrogenated bisphenol A type epoxy resin. From the viewpoint of reducing yellowing of the cured product of the film adhesive of the present invention and improving transparency, it is preferred to use an epoxy resin having an alicyclic structure, and more preferably an epoxy resin having a hydrogenated bisphenol structure.

The epoxy resin may be a liquid epoxy resin or a solid epoxy resin. From the viewpoint of suppressing stickiness and improving handling properties, it is preferred to use a solid epoxy resin alone, or to use a solid epoxy resin and a liquid epoxy resin together.

The weight average molecular weight of the epoxy resin is preferably 100 to 3000, more preferably 200 to 1500. The weight average molecular weight is the value obtained by GPC (Gel Permeation Chromatography) analysis.

In the solid components (components other than the solvent) of the film adhesive of the present invention, the content of the epoxy resin is preferably 10-80 mass %, more preferably 25-80 mass %, further preferably 30-80 mass %, further preferably 40-75 mass %, further preferably 50-75 mass %, and most preferably 60-70 mass %.

(Phenoxy resin) The film adhesive of the present invention contains at least one phenoxy resin. The phenoxy resin is a component that suppresses the film adhesion at room temperature (23°C) and imparts film-forming properties (film-forming properties) when forming a film adhesive. In addition, in the present invention, the so-called phenoxy resin refers to a resin having an epoxy equivalent (mass of resin corresponding to 1 equivalent of epoxy group) exceeding 3000 g/eq. That is, a resin having an epoxy equivalent of 3000 g/eq or less is classified as an epoxy resin even if it has a phenoxy resin structure.

Phenoxy resins can be obtained according to conventional methods. For example, they can be obtained by reacting bisphenol or biphenol compounds with epihalogen alcohols such as epichlorohydrin, or by reacting liquid epoxy resins with bisphenol or biphenol compounds.

The glass transition temperature (Tg) of the phenoxy resin is preferably 160°C or lower, more preferably 120°C or lower, further preferably less than 110°C, further preferably 100°C or lower, and particularly preferably 90°C or lower. The Tg of the phenoxy resin is also preferably 0°C or higher, preferably 10°C or higher, preferably 20°C or higher, and can be set to 30°C or higher, can be set to 40°C or higher, can be set to 50°C or higher, can be set to 60°C or higher, can be set to 70°C or higher, and is preferably 80°C or higher. The Tg of the phenoxy resin is preferably 0 to 160°C, preferably 10 to 125°C, preferably 30 to 120°C, preferably 50 to 120°C, preferably 70 to 120°C, preferably 80 to 120°C, preferably 80 to 120°C, preferably 80 to 110°C or higher, and preferably 80 to 100°C. From the viewpoint of increasing the storage elastic modulus of the cured product of the film adhesive of the present invention at room temperature (23°C), the Tg of the phenoxy resin is preferably 80°C or higher. From the viewpoint of further improving the transparency of the cured product of the film-like adhesive of the present invention, the Tg of the phenoxy resin is preferably 10 to 120°C, preferably 80 to 120°C, preferably 80°C or more and less than 110°C, and preferably 80 to 100°C. The Tg of the above-mentioned phenoxy resin is the peak temperature of tanδ in the dynamic viscoelasticity measurement. Specifically, Tg can be determined as follows. A solution in which the phenoxy resin is dissolved is applied to a release film, and heat-dried to form a film (polymer film) composed of the phenoxy resin on the release film. The release film was peeled off and removed from the polymer film, and the polymer film was measured using a dynamic viscoelasticity measuring device (trade name: Rheogel-E4000F, manufactured by UBM) at a measuring temperature range of 20 to 300°C, a heating rate of 5°C/min, and a frequency of 1 Hz. The obtained tanδ peak temperature (the temperature at which tanδ shows a maximum) was set as Tg.

The weight average molecular weight of the above-mentioned phenoxy resin is usually 10,000 or more. The upper limit is not particularly limited, but is practically 5,000,000 or less. The weight average molecular weight of the above-mentioned phenoxy resin is obtained by polystyrene conversion using GPC (Gel Permeation Chromatography).

When focusing on the skeleton of the phenoxy resin, a bisphenol A type phenoxy resin, a phenoxy resin containing a biphenyl skeleton and a cyclohexane skeleton, or a bisphenol F + 1,6-hexanediol diepoxypropyl ether type phenoxy resin can be preferably used in the present invention.

In the film adhesive of the present invention, the content of the phenoxy resin can be set to 30-500 mass parts, 30-400 mass parts, 30-300 mass parts, 40-250 mass parts, 40-120 mass parts, and preferably 40-80 mass parts relative to 100 mass parts of the epoxy resin.

(Photocationic polymerization initiator) The film-like adhesive of the present invention contains a photocationic polymerization initiator containing antimony in the anionic part (hereinafter, also referred to as "photocationic polymerization initiator"). The so-called "containing antimony in the anionic part" means that the anionic part has an anion containing an antimony atom. The photocationic polymerization initiator is preferably an onium salt having the _above -mentioned anionic part and cationic part, and is more preferably an aromatic onium salt. The anionic part of ^the photocationic polymerization initiator only needs to be an anion containing an antimony atom, and is preferably _SbF4- and ^SbF6- , and is more preferably _SbF6- ^. The cationic part of the photo-cationic polymerization initiator is not particularly limited, and is preferably a cobalt compound ion, an iodine compound ion, an ammonium compound ion, a phosphonium compound ion, a pyridinium compound ion, etc., and more preferably a cobalt compound ion and an iodine compound ion. The cationic part is not particularly limited as long as it is a structure that functions as a photo-cationic polymerization initiator. From the viewpoint of light absorption, it is preferably an aromatic group. As the aromatic group, an aryl group is preferred, and a phenyl group is more preferred. If the photo-cationic polymerization initiator is classified according to the type of cationic site, it can also be called a cobalt salt compound, an iodine salt compound, an ammonium salt compound, a phosphonium salt compound, or a pyridinium salt compound. These can be used alone or in combination of two or more. The photo-cationic polymerization initiator is preferably a UV cationic polymerization initiator.

In the film adhesive of the present invention, the content of the photocatalytic polymerization initiator can be set to 0.5-30 mass parts, 1-20 mass parts, 1-15 mass parts, preferably 2-10 mass parts, and preferably 2-8 mass parts relative to 100 mass parts of the epoxy resin.

(Additive) The film adhesive of the present invention may also contain a silane coupling agent as an additive. By using a silane coupling agent, the adhesion to the adherend can be further improved, and as a result, the bonding reliability can be improved. The silane coupling agent is formed by at least one hydrolyzable group such as an alkoxy group or an aryloxy group bonded to a silicon atom, and in addition, an alkyl group, an alkenyl group, or an aryl group may also be bonded. The alkyl group is preferably substituted by an amino group, an alkoxy group, an epoxy group, or a (meth)acryloyloxy group, and more preferably substituted by an amino group (preferably an aniline group), an alkoxy group (preferably a glyoxypropoxy group), or a (meth)acryloyloxy group. Examples of silane coupling agents include 2-(3,4-epoxyhexyl)ethyltrimethoxysilane, 3-glycyrrhizic acid propyltrimethoxysilane, 3-glycyrrhizic acid propyltriethoxysilane, 3-glycyrrhizic acid propylmethyldimethoxysilane, 3-glycyrrhizic acid propylmethyldiethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, methyltrimethoxysilane, Silane, methyl triethoxysilane, phenyl trimethoxysilane, phenyl triethoxysilane, N-phenyl-3-aminopropyl trimethoxysilane, 3-methacryloyloxypropyl methyl dimethoxysilane, 3-methacryloyloxypropyl trimethoxysilane, 3-methacryloyloxypropyl methyl diethoxysilane, 3-methacryloyloxypropyl triethoxysilane, etc.

When the film adhesive of the present invention includes a silane coupling agent, the content of the silane coupling agent can be set to 0.1-20 parts by mass, 0.5-10 parts by mass, 1-7 parts by mass, preferably 1-5 parts by mass, and preferably 1-3 parts by mass, relative to 100 parts by mass of the epoxy resin.

The film adhesive of the present invention may also contain a hardening delay agent as an additive. By using the hardening delay agent, the adhesion with the adherend is improved, and the bonding strength is improved. As the hardening delay agent, the commonly used adhesives can be used. As the hardening delay agent, polyether compounds can be listed. As the above-mentioned polyether compounds, for example, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, calixarene, crown ether compounds, etc. can be listed. Among them, crown ether compounds are more suitable. As crown ethers, 18-crown-6-ether, 15-crown-5-ether, etc. can be listed.

When the film adhesive of the present invention includes a curing retarder, the content of the curing retarder can be set to 0.01 to 20 parts by mass, 0.1 to 10 parts by mass, 0.1 to 8 parts by mass, preferably 0.1 to 5 parts by mass, and preferably 0.1 to 3 parts by mass, relative to 100 parts by mass of the epoxy resin.

The film adhesive of the present invention may also contain a filler. That is, the film adhesive of the present invention may be in a form containing a filler or in a form not containing a filler. However, the film adhesive of the present invention exhibits suitable bonding even without a filler. The filler is preferably an inorganic filler. Examples of inorganic fillers include: ceramics such as silicon dioxide, clay, gypsum, calcium carbonate, barium sulfate, alumina, ceria, magnesium oxide, silicon carbide, silicon nitride, aluminum nitride, and boron nitride; metals or alloys such as aluminum, copper, silver, gold, nickel, chromium, lead, tin, zinc, palladium, and solder; and various inorganic powders such as carbon nanotubes and graphene. The inorganic filler material may also be subjected to surface treatment or surface modification. The agents used for such surface treatment or surface modification include: silane coupling agent, phosphoric acid or phosphoric acid compound, surfactant, etc. The shapes of the inorganic filler material include flake, needle, filament, spherical, and scale-shaped ones. However, from the perspective of high filling and fluidity, spherical particles are preferred.

When the film-like adhesive of the present invention contains a filler, the content of the filler in the film-like adhesive is preferably 70% by mass or less, more preferably 60% by mass or less, preferably 50% by mass or less, and preferably 40% by mass or less in the solid content of the film-like adhesive. When the film-like adhesive of the present invention contains a filler, the content of the filler in the film-like adhesive can be set to 1% by mass or more, can be set to 2% by mass or more, and is preferably set to 4% by mass or more. When the film adhesive of the present invention contains a filler, the content of the filler in the film adhesive can be set to 71-70 mass %, 2-60 mass %, 4-50 mass %, 4-40 mass %, and preferably 10-30 mass % based on the solid content of the film adhesive.

The film adhesive of the present invention may further contain an organic solvent, an ion-trapping agent, a hardening catalyst, a viscosity modifier, an antioxidant, a flame retardant, a colorant, etc. For example, it may contain other additives of International Publication No. 2017/158994.

The total content of the epoxy resin, the phenoxy resin, and the photocatalytic ion polymerization initiator in the film adhesive of the present invention may be, for example, 30% by mass or more, preferably 40% by mass or more, and further preferably 50% by mass or more. The ratio may also be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more.

Here, in the present invention, the so-called "film" refers to a thin film with a thickness of less than 200 μm. There is no particular limitation on the shape, size, etc., and it can be appropriately adjusted according to the usage. The thickness of the film adhesive of the present invention and the cured product formed by curing the film adhesive are usually 1 to 100 μm, preferably 2 to 80 μm, and more preferably 5 to 50 μm. The thickness can be measured by contact or linear meter method (desktop contact thickness meter).

The glass transition temperature (Tg) of the cured product of the film-like adhesive of the present invention is preferably above 64°C, and more preferably above 80°C. The Tg of the cured product of the above-mentioned film-like adhesive is the peak temperature of tanδ in the dynamic viscoelasticity measurement. Specifically, Tg can be determined as follows. Use a laminating machine to layer the film-like adhesive at 70°C until the thickness reaches 0.3 mm, and use a mercury lamp to irradiate ultraviolet rays at 23°C and 500 mJ/ ^cm2 to cause a curing reaction. Cut the obtained cured sample into 5 mm width to make a measurement sample. The sample was measured using a dynamic viscoelasticity measuring device RSAIII (manufactured by TA Instruments) at a chuck distance of 20 mm, a frequency of 10 Hz, a measuring temperature range of -40°C to 250°C, and a heating rate of 5°C/min. The obtained tanδ peak temperature (the temperature at which tanδ shows a maximum) was set as the Tg of the cured film adhesive. Here, the Tg of the cured film adhesive of the present invention is X°C. When there are more than two Tgs of the cured product, the Tg on the lowest temperature side is X°C. Therefore, for example, when the Tg of the cured product of the film adhesive of the present invention is 80°C or higher, when the Tg of the cured product is two or more, it means that the Tg of the lowest temperature side is 80°C or higher. The Tg of the cured product of the film adhesive of the present invention can also be preferably set to 80°C or higher, more preferably set to 90°C or higher, and more preferably set to 100°C or higher. The Tg of the cured product of the film adhesive of the present invention is preferably 80-150°C, more preferably 80-140°C, more preferably 90-130°C, and more preferably 100-130°C. Tg can also be set to 110-125°C.

The parallel light transmittance of the cured product of the film-like adhesive of the present invention is preferably 70% or more. In the present invention, the above-mentioned parallel light transmittance refers to the parallel light transmittance at 400 nm. Film-like adhesives are generally prone to yellowing due to irradiation with energy rays. Therefore, the transparency can be evaluated using the parallel light transmittance of the obtained cured product at the above-mentioned wavelength as an indicator. That is, the parallel light transmittance at 400 nm can represent the parallel light transmittance in the visible light range outside 400 nm. The parallel light transmittance of the cured product of the film-like adhesive of the present invention is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. The upper limit of the parallel light transmittance is 100% in practice. Therefore, the parallel light transmittance of the cured product of the film-like adhesive of the present invention is preferably 80 to 100 ^% . The parallel light transmittance can be measured using a spectrophotometer. Specifically, the parallel light transmittance of the cured product is determined as follows. Use a laminating machine to layer the film-like adhesive at 70°C until the thickness reaches 0.3 mm, and cure it under the condition of 500 mJ/cm2. Cut the obtained cured sample into 5 cm squares to prepare a measurement sample. Use a spectrophotometer (manufactured by Shimadzu Corporation, UV-visible spectrophotometer UV-1800) to determine the parallel light transmittance of the measurement sample at a wavelength of 400 nm.

The storage elastic modulus of the cured product of the film adhesive of the present invention at room temperature (23°C) (hereinafter, also referred to as "storage elastic modulus") is preferably 0.8 GPa or more. The storage elastic modulus of the cured product is more preferably 1.0 GPa or more, and further preferably 1.2 GPa or more. The storage elastic modulus of the cured product is preferably 7.0 GPa or less, more preferably 6.0 GPa or less, further preferably 5.5 GPa or less, and particularly preferably 5.0 GPa or less. The storage elastic modulus of the above-mentioned cured product can be set to 0.8 to 7.0 GPa, or 0.8 to 6.0 GPa, preferably 1.0 to 5.5 GPa, preferably 1.0 to 5.0 GPa, preferably 1.0 to 4.0 GPa, or preferably 1.0 to 3.0 GPa. The storage elastic modulus of the above-mentioned cured product is determined as follows. A film adhesive is laminated at 70°C using a laminating machine until the thickness becomes 0.3 mm, and cured at 500 mJ/ ^cm2 . The obtained cured sample is cut into 5 mm width to prepare a measurement sample. Using a dynamic viscoelasticity tester RSAIII (manufactured by TA Instruments), the sample was heated from -40°C to 250°C at a heating rate of 5°C/min under the conditions of a chuck distance of 20 mm and a tension frequency of 10 Hz to determine the storage elastic modulus of the sample at 23°C.

The storage elastic modulus of the cured product of the film adhesive of the present invention can be controlled by the chemical structure (skeleton, type of functional group, etc.), molecular weight, epoxy equivalent, and content of the epoxy resin, the chemical structure (skeleton, type of functional group, etc.), molecular weight, glass transition temperature, and content of the phenoxy resin, the chemical structure (skeleton, type of functional group, etc.) and content of the photopolymerization initiator, and the type or content of the filler and other additives in the adhesive.

The film adhesive of the present invention can be obtained by preparing a composition (varnish) obtained by mixing the components of the film adhesive, applying the composition on a release film or a desired substrate, and drying as needed. The composition (varnish) obtained by mixing the components of the adhesive layer usually contains an organic solvent. As a coating method, a known method can be appropriately adopted, for example, a method using a roller knife coater, a gravure coater, a die-mouth coater, a reverse coater, etc. can be listed. Drying is sufficient as long as the organic solvent can be removed without substantially causing a hardening reaction and a film-like adhesive can be formed. For example, it can be carried out by maintaining a temperature of 80 to 150°C for 1 to 20 minutes.

From the viewpoint of inhibiting the curing reaction of the film adhesive (curing reaction of the epoxy resin), the film adhesive of the present invention is preferably stored in a light-shielded state before use (before the curing reaction). The temperature conditions during the light-shielded storage are not particularly limited and can be either room temperature or refrigerated.

[Manufacturing method of device] The manufacturing method of the device of the present invention is not particularly limited as long as it is a method of manufacturing the device using the film-like adhesive of the present invention. One implementation of the manufacturing method of the device of the present invention includes bonding a component using the film-like adhesive of the present invention. Therefore, the device of the present invention includes a structure in which the component is bonded using the film-like adhesive of the present invention. There is no particular limitation on the component of the component device to which the film-like adhesive of the present invention is applied, and examples thereof include: the above-mentioned functional elements and functional layers, and laminates thereof. One embodiment of the method for manufacturing the device of the present invention includes bonding the components, for example, between laminates containing functional elements (laminates containing functional elements and various functional layers arranged on one or both sides thereof), between a substrate and a laminate containing functional elements, between a first substrate and a second substrate (a laminate containing functional elements can also be formed on either one of the first and second substrates, or on the side of both substrates opposite to the adhesive layer), etc., by means of the film-like adhesive of the present invention. Therefore, in one embodiment of the manufacturing method of the device of the present invention, the following steps are included: the film adhesive of the present invention is arranged on the surface of a component of the device, and another component of the device is arranged through the film adhesive to make the film adhesive undergo a hardening reaction.

In the manufacturing method of the device of the present invention, the conditions of the above-mentioned curing reaction can be appropriately set by considering the type of curing agent, the heat resistance of the functional element, etc. For example, the adhesive layer can be fully cured by irradiating 100 to 1500 mJ/ ^cm2 of ultraviolet light using a mercury lamp or the like. From the perspective of reducing the irradiation amount, the upper limit of the irradiation amount is preferably 700 mJ/ ^cm2 or less, and more preferably 600 mJ/ ^cm2 or less. [Example]

The present invention is described in more detail based on the examples and comparative examples, but the present invention is not limited to the forms of the following examples. In addition, the so-called room temperature refers to 23°C, MEK is methyl ethyl ketone, PET is polyethylene terephthalate, and UV is ultraviolet light. Unless otherwise specified, "%" and "parts" are based on mass.

<Preparation of film-like adhesive> (Example 1) In a 1000 ml separable flask, 70 parts by mass of ST-3000 (trade name, hydrogenated bisphenol A type liquid epoxy resin, epoxy equivalent: 225 g/eq, manufactured by Nippon Steel Chemical & Material Co., Ltd.) as an epoxy resin, 30 parts by mass of YP-50 (trade name, bisphenol A type phenoxy resin, Tg: 84°C, manufactured by Nippon Steel Chemical & Material Co., Ltd.) as a phenoxy resin, and 30 parts by mass of MEK were heated and stirred at a temperature of 110°C for 2 hours to obtain a resin varnish. Furthermore, the resin varnish was transferred to an 800 ml planetary mixer, 2 parts by mass of WPI-116 (trade name, UV cationic polymerization initiator (iodine salt type, anionic part: SbF ₆ ^- ), manufactured by FUJIFILM Wako Pure Chemical Co., Ltd.) was added as a polymerization initiator, and the mixture was stirred and mixed at room temperature for 1 hour, and then vacuum defoamed to obtain a mixed varnish. Subsequently, the obtained mixed varnish was coated on a PET film with a thickness of 38 μm and a surface release treatment, and heat dried at 130°C for 10 minutes to obtain a film-like adhesive with a length of 300 mm, a width of 200 mm, and a thickness of 20 μm with a release film.

(Example 2) The phenoxy resin was set to 86 parts by mass of YX7200B35 (trade name, phenoxy resin containing biphenyl skeleton and cyclohexane skeleton, Tg: 150°C, non-volatile matter is 35% by mass, epoxy equivalent: 9000 g/eq, manufactured by Mitsubishi Chemical Co., Ltd.) (wherein the phenoxy resin (solid content) is 30 parts by mass). A film-like adhesive for a releasable film was obtained in the same manner as in Example 1.

(Example 3) The epoxy resin was set to 70 parts by mass of 828 (trade name, bisphenol A type epoxy resin, epoxy equivalent: 185 g/eq, manufactured by Nippon Steel Chemical & Material Co., Ltd.), and a film-like adhesive with a peelable film was obtained in the same manner as in Example 1.

(Example 4) 1 part by mass of KBM-402 (trade name, silane coupling agent (3-glycidoxypropylmethyldimethoxysilane), manufactured by Shin-Etsu Chemical Co., Ltd.) was added as an additive to the mixed varnish, and a film-like adhesive with a peeling film was obtained in the same manner as in Example 1.

(Example 5) 0.1 parts by weight of 18-crown-6-ether (trade name, hardening delay agent, manufactured by Tokyo Chemical Industry Co., Ltd.) was added as an additive to the mixed varnish. A film-like adhesive with a peeling film was obtained in the same manner as in Example 1.

(Example 6) The epoxy resin was set to 50 parts by mass of ST-3000 (trade name, hydrogenated bisphenol A type liquid epoxy resin, epoxy equivalent: 225 g/eq, manufactured by Nippon Steel Chemical & Material Co., Ltd.) and 20 parts by mass of YX8040 (trade name, hydrogenated bisphenol A type solid epoxy resin, epoxy equivalent: 1200 g/eq, manufactured by Mitsubishi Chemical Co., Ltd.), and a film-like adhesive with a peelable film was obtained in the same manner as in Example 1.

(Example 7) 33 parts by mass of YC100C-MLA (trade name, silica filler slurry, solid content: 60%, manufactured by Admatechs Co., Ltd.) (including 20 parts by mass of silica filler) was added to the mixed varnish as a filler. In addition, a film-like adhesive with a peeling film was obtained in the same manner as in Example 1.

(Example 8) A film-like adhesive with a peelable film was obtained in the same manner as in Example 1 except that the blending amount of the epoxy resin was set to 50 parts by mass, the blending amount of the phenoxy resin was set to 50 parts by mass, and the polymerization initiator was set to 2 parts by mass of CPI-101A (trade name, UV cationic polymerization initiator (copper salt type, anionic part: SbF ₆ ^- ), manufactured by San-Apro Co., Ltd.).

(Example 9) A film-like adhesive with a peelable film was obtained in the same manner as in Example 4 except that the polymerization initiator was changed to 2 parts by mass of CPI-101A (trade name, UV cationic polymerization initiator (copper salt type, anionic part: SbF ₆ ^- ), manufactured by San-Apro Co., Ltd.).

(Example 10) A film-like adhesive with a peeling film was obtained in the same manner as in Example 1 except that the blending amount of the epoxy resin was set to 30 parts by mass and the blending amount of the phenoxy resin was set to 70 parts by mass.

(Example 11) The epoxy resin blending amount was set to 50 parts by mass, and the phenoxy resin was set to 50 parts by mass of YX7180 (trade name, bisphenol F + 1,6-hexanediol diglycidyl ether type phenoxy resin, Tg: 15°C, manufactured by Mitsubishi Chemical Co., Ltd.), and a film-like adhesive for a releasable film was obtained in the same manner as in Example 1.

(Example 12) The phenoxy resin was set to 30 parts by mass of YX7180 (trade name, bisphenol F + 1,6-hexanediol diglycidyl ether type phenoxy resin, Tg: 15°C, manufactured by Mitsubishi Chemical Co., Ltd.), and a film-like adhesive for a releasable film was obtained in the same manner as in Example 1 except that the phenoxy resin was set to 30 parts by mass of YX7180 (trade name, bisphenol F + 1,6-hexanediol diglycidyl ether type phenoxy resin, Tg: 15°C, manufactured by Mitsubishi Chemical Co., Ltd.).

(Example 13) 67 parts by mass of YC100C-MLA (trade name, silica filler slurry, solid content: 60%, manufactured by Admatechs Co., Ltd.) (including 40 parts by mass of silica filler) was added to the mixed varnish as a filler material. In addition, a film-like adhesive with a peeling film was obtained in the same manner as in Example 1.

(Comparative Example 1) The blending amount of the epoxy resin was set to 40 parts by mass, the blending amount of the phenoxy resin YX7200B35 (trade name, phenoxy resin containing a biphenyl skeleton and a cyclohexane skeleton, Tg: 150°C, non-volatile matter: 35% by mass, epoxy equivalent: 9000 g/eq, manufactured by Mitsubishi Chemical Co., Ltd.) was set to 171 parts by mass (of which the phenoxy resin (solid content) was 60 parts by mass), and the polymerization initiator was set to CPI-100P (trade name, UV cationic polymerization initiator (copper salt type, anionic part: PF ₆ ^- ), manufactured by San-Apro Co., Ltd.), 2 parts by mass, and except for this, a film-like adhesive with a peelable film was obtained in the same manner as in Example 2.

(Comparative Example 2) The blending amount of the epoxy resin was set to 50 parts by mass, the blending amount of the phenoxy resin YX7200B35 (trade name, phenoxy resin containing a biphenyl skeleton and a cyclohexane skeleton, Tg: 150°C, non-volatile matter: 35% by mass, epoxy equivalent: 9000 g/eq, manufactured by Mitsubishi Chemical Co., Ltd.) was set to 142 parts by mass (of which the phenoxy resin (solid content) was 50 parts by mass), and the polymerization initiator was set to CPI-200K (trade name, UV cationic polymerization initiator (copper salt type, anionic part: PF ₃ (C ₂ F ₅ ) ₃ ^- ), manufactured by San-Apro Co., Ltd.), 2 parts by mass, and except for this, a film-like adhesive with a peelable film was obtained in the same manner as in Example 2.

(Comparative Example 3) A film adhesive with a peeling film was obtained in the same manner as in Comparative Example 1.

(Comparative Example 4) A film-like adhesive with a peelable film was obtained in the same manner as in Example 1 except that the polymerization initiator was changed to 2 parts by mass of CPI-100P (trade name, UV cationic polymerization initiator (copper salt type, anionic part: PF ₆ ^- ), manufactured by San-Apro Co., Ltd.).

(Comparative Example 5) A film-like adhesive with a peelable film was obtained in the same manner as in Example 1 except that the polymerization initiator was changed to 2 parts by mass of CPI-200K (trade name, UV cationic polymerization initiator (copper salt type, anionic part: PF ₃ (C ₂ F ₅ ) ₃ ^- ), manufactured by San-Apro Co., Ltd.).

(Comparative Example 6) A film-like adhesive with a peeling film was obtained in the same manner as in Comparative Example 2 except that 50 parts by mass of SG-708-6 (trade name, acrylic resin, Tg: 5°C, manufactured by Nagase ChemteX Co., Ltd.) was used instead of the phenoxy resin and 2 parts by mass of TPO (trade name, UV radical polymerization initiator (2,4,6-trimethylbenzyl-diphenyl-phosphine oxide), manufactured by Tokyo Chemical Industry Co., Ltd.) was used as the polymerization initiator.

(Comparative Example 7) A film-like adhesive with a peeling film was obtained in the same manner as in Comparative Example 6 except that the polymerization initiator was set to 2 parts by mass of benzophenone (UV free radical polymerization initiator, manufactured by Tokyo Chemical Industry Co., Ltd.).

(Comparative Example 8) A film-like adhesive with a peelable film was obtained in the same manner as in Comparative Example 6 except that the polymerization initiator was changed to 2 parts by mass of WPI-116 (trade name, UV cationic polymerization initiator (iodonium salt type, anionic part: SbF ₆ ^- ), manufactured by FUJIFILM Wako Pure Chemical Co., Ltd.).

The compositions of the film adhesives of the Examples and Comparative Examples are shown in Table 1.

<Preparation of hardened product (hardened sample) and confirmation of the presence or absence of heat> The film adhesive attached to the release film obtained in each embodiment and comparative example was peeled off, and the film adhesive was laminated at 70°C using a laminating machine until the thickness became 0.3 mm to obtain a laminated sample. The laminated sample was treated at room temperature (23°C) with the UV irradiation amount listed in the "UV irradiation amount" column of "hardened sample preparation conditions" in Table 1 to obtain a hardened sample (hardened product) for evaluation of the storage elastic modulus and parallel light transmittance described later. At this time, the surface temperature of the sample before and after UV irradiation was measured, and the presence or absence of heat caused by UV irradiation was also evaluated. The surface temperature was measured using a non-contact surface thermometer (FT3700, manufactured by Hioki Electric Co., Ltd.), and the surface temperature after UV irradiation was measured within 5 seconds after UV irradiation. The surface temperature difference before and after UV irradiation (surface temperature after UV irradiation - surface temperature before UV irradiation) is recorded in Table 1.

<Measurement of storage elastic modulus and glass transition temperature of cured product> As an indicator of the curing state of the film adhesive, the storage elastic modulus and glass transition temperature of the cured product of the film adhesive were measured. The hardened sample prepared above was cut into 5 mm width to prepare a measurement sample. Using the measuring device RSAIII (manufactured by TA Instruments), under the conditions of a chuck distance of 20 mm and a frequency of 10 Hz, the viscoelastic behavior of each measurement sample when the temperature was increased from -40℃ to 250℃ at a heating rate of 5℃/min was measured, and the storage elastic modulus and Tg at 23℃ were obtained. Tg is set as the temperature showing the maximum value of tanδ. When there are two or more maximum values, the temperature showing the maximum value on the low temperature side is set as Tg. The measurement results are shown in Table 1.

<Parallel light transmittance measurement> The transparency of the cured film adhesive was evaluated based on the parallel light transmittance at a wavelength of 400 nm. The cured sample prepared above was cut into 5 cm squares to prepare measurement samples. The parallel light transmittance of each measurement sample obtained was measured using a spectrophotometer (manufactured by Shimadzu Corporation, UV-visible spectrophotometer UV-1800) to determine the parallel light transmittance at a wavelength of 400 nm.

<Bonding reliability> The curing state and bonding strength of the film adhesive were evaluated using the change rate of the bonding force (shear strength) of the adherend (glass plate and dummy chip) bonded by the cured film adhesive as an indicator. 1) Sample preparation First, the film adhesive with a peel film obtained in each embodiment and comparative example (before curing) was hot-pressed onto one side of a dummy silicon wafer (size 8 inches, thickness 350 μm) at a temperature of 70°C and a pressure of 0.3 MPa using a manual laminating machine (trade name: FM-114, manufactured by TECHNOVISION). Thereafter, after the release film is peeled off from the film adhesive, the dicing film and dicing frame (trade name: DTF2-8-1H001, manufactured by DISCO Corporation) are pressed onto the surface of the film adhesive opposite to the dummy silicon wafer at room temperature and a pressure of 0.3 MPa using the above-mentioned manual laminating machine. Next, a dicing device (trade name: DFD-6340, manufactured by DISCO) equipped with a double-axis dicing blade (Z1: NBC-ZH2050 (27HEDD), manufactured by DISCO / Z2: NBC-ZH127F-SE (BC), manufactured by DISCO) was used to dicing (cut) the dummy silicon wafer side in the thickness direction of the film adhesive to a depth reaching the entire thickness of the film adhesive, so as to obtain a dummy wafer with the adhesive attached on the dicing film. Next, the dummy chip with the above-mentioned adhesive was picked up from the dicing film by a die bonder (trade name: DB-800, manufactured by Hitachi High-Technologies), and the adhesive side of the dummy chip with the above-mentioned adhesive was bonded to a glass plate (thickness: 700 μm, length: 10 mm × width: 10 mm) as a substrate to be bonded at the center of the glass plate and heat-pressed at 80°C, pressure: 0.1 MPa (load: 400 gf), and time: 1.0 second. Next, UV irradiation was performed from the glass plate side with a specific UV irradiation amount (described in the "UV irradiation amount" column of the "reliability evaluation" in the table) by a UV irradiator to cure the adhesive. In this way, a test piece having a virtual chip-hardened adhesive-glass plate was obtained. 2) Measurement of shear strength The shear strength between the hardened adhesive of the test piece obtained above and the glass plate was measured using a universal bonding strength tester (trade name: 4000PXY series, manufactured by Nordson Advanced Technology). The test conditions were set to a measurement speed of 100 μm/s and a measurement height of 740 μm, and the shear strength was measured when the virtual chip in the test piece was pushed out horizontally relative to the test piece. The above shear strength was measured at two measurement temperatures (normal temperature (23°C) and high temperature (100°C)), and the change rate of the shear strength was calculated and evaluated according to the following evaluation criteria. The shear strength is measured by storing the adherends bonded by the cured film adhesive at the above-mentioned test temperature for 1 minute. Evaluations of A or above are considered qualified. Furthermore, each of the film adhesives of Examples 1 to 13 exhibits sufficiently high shear strength immediately after curing by UV irradiation. Shear strength change rate = {(shear strength at room temperature - shear strength at high temperature) / shear strength at room temperature} × 100[%] -Evaluation criteria- AA: Shear strength change rate is less than 5% A: Shear strength change rate is 5% or more and less than 10% B: Shear strength change rate is 10% or more and less than 40% C: Shear strength change rate is 40% or more

[Table 1-1] Embodiment 1 2 3 4 5 6 7 8 9 10 11 12 13 Epoxy ST-3000 (Hydrogenated bisphenol A type liquid epoxy resin, 225 g/eq) 70 70 70 70 50 70 50 70 30 50 70 70 YX8040 (Hydrogenated bisphenol A type solid epoxy resin, 1200 g/eq) 20 828 (Bisphenol A type liquid epoxy resin, 185 g/eq) 70 Phenoxy resin YP-50 (phenoxy resin, Tg is 84℃) 30 30 30 30 30 30 50 30 70 30 YX7200B35 (phenoxy resin, Tg 150℃) 30 YX7180 (phenoxy resin, Tg 15°C) 50 30 Acrylic resin SG-708-6 (acrylic resin, Tg is 5℃) Polymerization initiator WPI-116 (Anionic site: SbF ₆ ^- ) 2 2 2 2 2 2 2 2 2 2 2 CPI-101A (Anionic site: SbF ₆ ^- ) 2 2 CPI-100P (Anionic site: PF ₆ ^- ) CPI-200K (Anionic site: PF ₃ (C ₂ F ₅ ) ₃ ^- ) TPO Benzophenone Additives KBM-402 (Silane coupling agent) 1 1 18-Crown-6-ether (hardening delay agent) 0.1 Filling material YC100C-MLA (silicon dioxide filler) 20 40 Hardened sample preparation conditions Thickness of laminated samples [mm] 300 300 300 300 300 300 300 300 300 300 300 300 300 UV irradiation dose [mJ/cm ² ] 500 500 500 500 500 500 500 500 500 500 500 500 500 Surface temperature difference of sample before and after UV irradiation [℃] 0 0 0 0 0 0 0 0 0 0 0 0 0 Storage elastic modulus evaluation Tg of hardened material[℃] 120 125 130 118 120 110 123 103 115 100 64 90 130 Storage elastic modulus of hardened material [GPa] 2.0 3.0 3.2 1.8 1.7 1.5 5.4 1.2 1.7 1.0 0.8 0.9 7.0 Transparency Rating Parallel light transmittance of cured product@400 nm[%] 95 80 87 92 92 93 83 95 93 94 93 94 70 Reliability Evaluation UV irradiation dose [mJ/cm ² ] 500 500 500 500 500 500 500 500 500 500 500 500 500 Reliability evaluation results A A A AA AA A AA A A A A A AA

[Table 1-2] Comparison Example 1 2 3 4 5 6 7 8 Epoxy ST-3000 (Hydrogenated bisphenol A type liquid epoxy resin, 225 g/eq) 40 50 40 70 70 50 50 50 YX8040 (Hydrogenated bisphenol A type solid epoxy resin, 1200 g/eq) 828 (Bisphenol A type liquid epoxy resin, 185 g/eq) Phenoxy resin YP-50 (phenoxy resin, Tg is 84℃) 30 30 YX7200B35 (phenoxy resin, Tg 150℃) 60 50 60 YX7180 (phenoxy resin, Tg 15°C) Acrylic resin SG-708-6 (acrylic resin, Tg is 5℃) 50 50 50 Polymerization initiator WPI-116 (Anionic site: SbF ₆ ^- ) 2 CPI-101A (Anionic site: SbF ₆ ^- ) CPI-100P (Anionic site: PF ₆ ^- ) 2 2 2 CPI-200K (Anionic site: PF ₃ (C ₂ F ₅ ) ₃ ^- ) 2 2 TPO 2 Benzophenone 2 Additives KBM-402 (Silane coupling agent) 18-Crown-6-ether (hardening delay agent) Filling material YC100C-MLA (silicon dioxide filler) Hardened sample preparation conditions Thickness of laminated samples [mm] 300 300 300 300 300 300 300 300 UV irradiation dose [mJ/cm ² ] 500 500 2000 500 500 500 500 500 Surface temperature difference of sample before and after UV irradiation [℃] 0 0 45 0 0 0 0 0 Storage elastic modulus evaluation Tg of hardened material[℃] 65 62 130 57 56 5 5 5 Storage elastic modulus of hardened material [GPa] 0.6 0.5 1.8 0.4 0.3 0.3 0.3 0.4 Transparency Rating Parallel light transmittance of cured product@400 nm[%] 65 67 30 70 72 10 13 15 Reliability Evaluation UV irradiation dose [mJ/cm ² ] 500 500 2000 500 500 500 500 500 Reliability evaluation results B B A B B C C C

In the above table, the amount of each component of the adhesive is expressed in parts by mass. A blank column means that the component is not contained.

As shown in the above table, when a photo-cationic polymerization initiator or a photo-radical polymerization initiator that does not contain antimony atoms in the anionic part is used as a polymerization initiator, if the UV irradiation dose is less than 500 mJ/ ^cm2 , the curing will be poor, resulting in a lower storage modulus and Tg, and then the reliability is poor (Comparative Examples 1-2, 4-5). Furthermore, the parallel light transmittance of Comparative Examples 1 and 2 is also poor. In addition, if the normal UV irradiation dose is set to 2000 mJ/ ^cm2 , although the storage modulus and Tg become higher, and then the reliability is improved, there is heat, and it becomes a result of poor parallel light transmittance (Comparative Example 3). The reason for the decrease in parallel light transmittance is believed to be yellowing caused by heat. If acrylic resin is used instead of phenoxy resin, regardless of the type of polymerization initiator, the storage elastic modulus, bonding reliability, and transparency are all poor under a relatively low UV irradiation of 500 mJ/ ^cm2 (Comparative Examples 6-8). The poor transparency is believed to be caused by the generation of white turbidity in Comparative Examples 6-8 and the low compatibility between acrylic resin and epoxy resin. In contrast, the film adhesives of Examples 1 to 13 that meet the requirements of the present invention have a high storage elastic modulus and Tg even when the UV irradiation dose is 500 mJ/ ^cm2 , showing excellent bonding reliability and parallel light transmittance. It can be seen that the film adhesive of the present invention can be fully cured with a relatively small irradiation dose, and the bonding force, transparency, and bonding reliability at high temperatures are all excellent. In addition, it can be seen that by using the film adhesive of the present invention in the manufacture of a device, the reliability of the device can be improved. In addition, it can be seen that if a phenoxy resin with a Tg of 120°C or less is used as the phenoxy resin, the transparency can be further improved (comparison between Example 1 and Example 2). It is known that if an epoxy resin having a hydrogenated bisphenol structure is used as the epoxy resin, the transparency can be further improved (comparison between Example 1 and Example 3). It is known that if a phenoxy resin having a Tg of 80°C or higher is used as the phenoxy resin, the adhesion of the cured product can be further improved. Specifically, the Tg or storage modulus of the cured product can be further improved, which contributes to the improvement of the adhesion (comparison between Example 1 and Examples 11 and 12). It is known that if the content of the filler is reduced to about 20% by mass of the solid content of the film adhesive, the parallel light transmittance can be more reliably increased to 80% or more (comparison between Example 7 and Example 13).

Although the present invention and its embodiments have been described, unless otherwise specified, the present invention is not limited to any details of the description and should be broadly interpreted in a manner that does not violate the spirit and scope of the invention as shown in the attached patent claims.

This application claims priority based on Japanese patent application No. 2022-105913 filed in Japan on June 30, 2022, the contents of which are incorporated herein by reference as a part of the description of this specification.

1: Film adhesive 2: Base material (supporting base material)

FIG. 1 is a cross-sectional view schematically showing the structure of a film-like adhesive with a peeling film prepared in an embodiment.

1: Film adhesive

2: Substrate (support substrate)

Claims (11)

An energy-ray-curing film-like transparent adhesive, comprising: an epoxy resin having a hydrogenated bisphenol structure, a phenoxy resin having a glass transition temperature of 80-120°C, and a photo-cationic polymerization initiator containing antimony in the cationic part. As in claim 1, the energy ray-curing film-like transparent adhesive, wherein the glass transition temperature of the cured product of the energy ray-curing film-like transparent adhesive is above 80°C. As in claim 1, the energy ray-curing transparent film adhesive, wherein the parallel light transmittance of the cured product of the energy ray-curing transparent film adhesive is 80% or more. As in claim 2, the energy ray-curing film-like transparent adhesive, wherein the parallel light transmittance of the cured product of the energy ray-curing film-like transparent adhesive is 80% or more. As in any one of claim 1 to 4, the energy ray-curing film-like transparent adhesive, wherein the storage elastic modulus of the cured product of the energy ray-curing film-like transparent adhesive at room temperature is greater than 1.0 GPa. An energy-ray-curable film-like transparent adhesive as claimed in any one of claims 1 to 4, which contains a silane coupling agent. An energy ray-curable film-like transparent adhesive as claimed in any one of claims 1 to 4, which contains a curing delay agent. An energy beam curable film-like transparent adhesive as claimed in any one of claims 1 to 4, which contains a filler material. A device containing an energy-ray-curing film-like transparent adhesive, comprising a structure in which components are bonded using the energy-ray-curing film-like transparent adhesive of any one of claims 1 to 8. A method for manufacturing a device using an energy ray-curing film-like transparent adhesive, comprising using the energy ray-curing film-like transparent adhesive of any one of claims 1 to 8 to bond a component. A method for manufacturing a device as claimed in claim 10, wherein the bonding is performed by the following steps: the film-like adhesive is disposed on the surface of one component of the device, and another component of the device is disposed through the film-like adhesive to cause the film-like adhesive to undergo a curing reaction; the curing reaction is performed by irradiating ultraviolet rays of 100~1500mJ/ ^cm2 .