Thermal radical polymerizable dry film and electronic device

Abstract

The invention provides a thermal radical polymerizable dry film and an electronic device which have excellent optical characteristics, sealing performance, low-temperature hardenability, storage stability and operability. The thermally radically polymerizable dry film is a dry film to be used in applications in which gaps between a plurality of micro-LEDs formed on a substrate are filled together and hardened, and contains a radically polymerizable organic compound and a thermal radical polymerization initiator having a 10-hour half-life temperature of 60-170 DEG C (inclusive), the radically polymerizable organic compound contains at least one of (i) a radically polymerizable polymer (a), (ii) a radically polymerizable oligomer (b) that is liquid at normal temperature and normal pressure, and (iii) a radically polymerizable monomer (c) that is liquid at normal temperature and normal pressure, the radically polymerizable polymer (a) having a glass transition temperature of-50 DEG C to 90 DEG C (inclusive) and a loss tangent tan [delta] 80 of 0.3 to 0.7.

Description

Technical Field

[0001] The present disclosure relates to a thermally free-radical polymerizable dry film and an electronic device including a cured product thereof. Background Art

[0002] Dry films are used as sealing materials for semiconductor elements. In particular, for materials disposed around partition walls in optical sensor modules or each light-emitting element of RGB in a display using light-emitting diodes (LEDs), a dry film with excellent processability and optical adaptability is sought.

[0003] For example, Japanese Patent Application Laid-Open No. 2022-110251 discloses a dry film formed from a curable composition containing a specific photoinitiator and a specific polymerization inhibitor and having a viscosity suitable for printing by an inkjet method. Conventionally, as a method for sealing LEDs, a method is known in which a dry film is filled into an area where a plurality of LEDs are arranged by hot pressing or the like, and the dry film is cured by ultraviolet irradiation. Japanese Patent Application Laid-Open No. 2022-22562 discloses a light-shielding dry film containing a polymer resin having a specific glass transition temperature and a specific weight-average molecular weight, an epoxy resin, and carbon black. Japanese Patent Application Laid-Open No. 2009-114423 discloses a method: using a sealing film containing a liquid crystalline polyester segment (A) and an amorphous vinyl polymer segment (B) having a crosslinking functional group in a specific ratio to seal sensors having a length of 8 mm × width of 8 mm × thickness of 700 μm arranged at intervals of 3 mm. Japanese Patent Application Laid-Open No. 2006-274085 discloses a liquid curable composition containing a vinyl polymer having an acryloyl group or the like and an initiator. In the examples of the literature, examples of forming a cured product having a thickness of about 2 mm by irradiating the liquid curable composition with light and examples of obtaining a cured product by filling the liquid curable composition into a mold are disclosed. Japanese Patent Application Laid-Open No. 2023-012356 discloses a dry film containing a curable composition containing a specific polyphenylene ether and a compound containing a functional group having a specific unsaturated carbon bond. Summary of the Invention

[0004] [Problems to be Solved by the Invention]

[0005] In recent years, in micro-LEDs that have been actively developed, the interval between LEDs is as narrow as 10 μm to 250 μm, and it is necessary to seal these minute grooves without gaps, but existing dry films cannot be sufficiently filled between the grooves to generate voids (also referred to as sealing performance).

[0006] The cured product of the sealed dry film has the following uses, that is, uses for properties that require maintaining high transparency for a long time without damaging the brightness of the micro-LED elements. On the other hand, in uses for suppressing color mixing of adjacent light-emitting elements, high light-shielding properties are required.

[0007] In addition, from the viewpoints of reducing thermal damage to parts or shortening the sealing process time, or suppressing local deformation or poor adhesion of the sealing layer caused by thermal shrinkage of the protective film during the curing process, a dry film that cures rapidly at low temperatures (also referred to as low-temperature curability) is sought.

[0008] In addition to this, if a curing reaction occurs during long-term storage, the sealing performance deteriorates. Therefore, it is required to maintain stable sealing performance (also referred to as storage stability) even after long-term storage.

[0009] Furthermore, a dry film that has no stickiness on the surface and is easy to operate during work (also referred to as operability) is sought.

[0010] Therefore, the subject of the present disclosure is to provide a dry film having excellent optical properties, sealing properties, low-temperature curability, storage stability, and operability.

[0011] [Technical means for solving the problem]

[0012] The inventors of the present invention repeatedly made intensive studies to solve the above problems, and thus completed the following present disclosure.

[0013] [1]: A thermally free-radical polymerizable dry film, which is a dry film containing a free-radical polymerizable organic compound and a thermally free-radical polymerization initiator, and the 10-hour half-life temperature of the thermally free-radical polymerization initiator is 60°C or higher and 170°C or lower.

[0014] [2]: The thermally free-radical polymerizable dry film according to [1], wherein the free-radical polymerizable organic compound contains a free-radical polymerizable polymer (a) having a glass transition temperature of -50°C or higher and 90°C or lower.

[0015] [3]: The thermally free-radical polymerizable dry film according to [1] or [2], wherein the free-radical polymerizable organic compound contains at least one of a free-radical polymerizable oligomer (b) and a free-radical polymerizable monomer (c) that is liquid at normal temperature and pressure.

[0016] [4]: The thermally free-radical polymerizable dry film according to any one of [1] to [3], characterized in that the storage elastic modulus (G'80) at 80°C obtained by dynamic viscoelasticity measurement is 5×10 4 Pa to 5×10 7 Pa.

[0017] [5]: The thermally free-radical polymerizable dry film according to any one of [1] to [4], characterized in that the loss tangent tanδ80 at 80 °C obtained by dynamic viscoelasticity measurement is 0.3 to 0.7.

[0018] [6]: The thermally free-radical polymerizable dry film according to any one of [1] to [5], wherein the dynamic friction coefficient of the surface of the thermally free-radical polymerizable dry film is 0.5 or less.

[0019] [7]: The thermally free-radical polymerizable dry film according to any one of [1] to [6], wherein a colorant is contained in an amount of 0.1% by mass to 80% by mass in 100% by mass of the total solid content.

[0020] [8]: The thermally free-radical polymerizable dry film according to any one of [1] to [7], having a thickness of 0.5 μm to 100 μm.

[0021] [9]: The thermally free-radical polymerizable dry film according to any one of [1] to [8], wherein the 10-hour half-life temperature of the thermally free-radical polymerization initiator is 100 °C or higher and 170 °C or lower, and the blending amount of the thermally free-radical polymerization initiator is 0.01% by mass to 20% by mass in the total solid content.

[0022]

[10] : The thermally free-radical polymerizable dry film according to any one of [1] to [9], for use in forming a light-shielding layer by filling the gaps between a plurality of micro LEDs formed on a substrate.

[0023]

[11] : The thermally free-radical polymerizable dry film according to any one of [1] to [9], for use in forming a sealing layer by filling the gaps between a plurality of micro LEDs formed on a substrate.

[0024]

[12] : The thermally free-radical polymerizable dry film according to any one of [1] to

[11] , wherein

[0025] the thermally free-radical polymerization initiator contains a peroxide-based thermally free-radical polymerization initiator, and the 10-hour half-life temperature of the peroxide-based thermally free-radical polymerization initiator is 60 °C or higher and 120 °C or lower,

[0026] the radical-polymerizable organic compound contains 95% by mass or more of a radical-polymerizable polymer (a) having a glass transition temperature of -50 °C or higher and 90 °C or lower in 100% by mass,

[0027] the radical-polymerizable polymer (a) contains a radical-polymerizable acrylic polymer.

[0028]

[13] : The thermal free-radical polymerizable dry film according to

[12] , wherein the 10-hour half-life temperature of the peroxide-based thermal free-radical polymerization initiator is 80 °C or higher and 110 °C or lower.

[0029]

[14] : The thermal free-radical polymerizable dry film according to

[12] or

[13] , wherein the blending amount of the peroxide-based thermal free-radical polymerization initiator is 0.01% by mass to 20% by mass in the total solid content.

[0030]

[15] : An electronic device, comprising a cured product of the thermal free-radical polymerizable dry film according to any one of [1] to

[14] .

[0031] [Effects of the Invention]

[0032] Through the present disclosure, a thermal free-radical polymerizable dry film, a cured product, and an electronic device excellent in optical properties, sealing properties, low-temperature curability, storage stability, and workability can be provided. [Description of the Drawings]

[0033] Figure 1 of (a), Figure 1 of (b) is a schematic cross-sectional view schematically showing an embodiment of the thermal free-radical polymerizable dry film of the present disclosure.

[0034] Figure 2 of (a) to (c-2) are schematic cross-sectional views showing the process of filling a dry film on a substrate having a plurality of micro LEDs.

[0035] Figure 3 is a schematic cross-sectional view schematically showing a test substrate used in the sealing property evaluation.

[0036] Figure 4 is a schematic cross-sectional view for explaining a method for evaluating the appearance after curing.

[0037] [Description of Reference Numerals]

[0038] 11: Thermal free-radical polymerizable dry film / dry film

[0039] 11': Cured product of dry film / cured product

[0040] 12: Release liner

[0041] 13: Protective film

[0042] 20: Optical semiconductor element

[0043] 21: Substrate

[0044] 22: Test substrate

[0045] 31: Glass plate Detailed Embodiments

[0046] Hereinafter, the thermally free-radical polymerizable dry film of the present disclosure will be described in more detail.

[0047] In addition, the embodiments described below are embodiments for illustrating an example of the present disclosure. The present disclosure is not limited to the following embodiments, and also includes modified examples implemented within the scope of not changing the gist of the present disclosure.

[0048] In this specification, the numerical range determined by "~" includes the numerical values described before and after "~". The so-called (meth)acrylic acid means acrylic acid and methacrylic acid. In addition, regarding the various components appearing in this specification, unless otherwise noted, each can be used independently alone, or two or more can be used in combination. In addition, when two or more are used in combination, the content rate uses the total value.

[0049] Figure 1 (a) of Figure 1 (b) is a schematic cross-sectional view of a laminate including the thermally free-radical polymerizable dry film 11 of an embodiment of the present disclosure. Figure 1 The laminate shown in (a) is a two-layer laminate formed by laminating the thermally free-radical polymerizable dry film 11 and the release liner 12. As Figure 1 shown in (b), a protective film 13 may also be formed on the surface of the thermally free-radical polymerizable dry film 11 opposite to the surface on which the release liner 12 is laminated. The laminate may also have other layers provided between the thermally free-radical polymerizable dry film 11 and the release liner 12 or the protective film 13 as needed. The thermally free-radical polymerizable dry film of the present disclosure is single-layer or multi-layer. In addition to the laminated structure in which a plurality of the same or different thermally free-radical polymerizable dry films are laminated, the multi-layer may also be a laminated structure in which the thermally free-radical polymerizable dry film of the present disclosure and layers other than the dry film described within the scope of not departing from the gist of the present disclosure are laminated.

[0050] The thermally free-radical polymerizable dry film of the present disclosure is preferably used for sealing optoelectronic semiconductor elements. Particularly preferably, it is in a form used for forming a sealing layer for a plurality of optoelectronic semiconductor elements used as light sources for displays. The sealing layer includes a layer that functions as a fixing material and a layer that functions as a light-shielding layer (also referred to as a partition wall). In addition, in addition to being used as a highly transparent sealing layer that does not impair the brightness of the semiconductor element, the sealing layer is also preferably used as a reflective layer, a high refractive index layer, or a light-shielding layer that reflects light. Displays using a plurality of optoelectronic semiconductor elements as light sources include, for example, organic electroluminescence (EL) display panels, liquid crystal display panels, micro-LED display panels, plasma display panels, electronic papers, and other displays that require high quality. As the optoelectronic semiconductor element, an organic EL light-emitting element, an LED semiconductor element, or a micro-LED semiconductor element is preferred.

[0051] Hereinafter, the thermally free-radical polymerizable dry film of the present disclosure may sometimes be simply referred to as a dry film.

[0052] The dry film is suitable for use in being hardened by being filled into the gaps between a plurality of micro-LEDs formed on a substrate, and is suitable for use in forming a sealing layer. It is preferably laminated in close contact with the adherend. As the adherend, in addition to the substrate on which a plurality of optoelectronic semiconductor elements (micro-LEDs) are formed, substrates having a substrate electrode portion containing a metal, substrates having a plurality of optoelectronic semiconductor element portions such as a backlight module and an organic EL can also be cited. Examples of the substrate include acrylic, polycarbonate, epoxy, polyimide, glass, glass epoxy, indium tin oxide (ITO), or polyethylene terephthalate.

[0053] The dry film has high followability for uneven surfaces, and thus a suitable usage method is to follow a plurality of optoelectronic semiconductor elements and fill between the optoelectronic semiconductor elements. By filling the dry film between the optoelectronic semiconductor elements and hardening it, the hardened product of the dry film functions as a sealing layer for fixing the optoelectronic semiconductor elements on the substrate.

[0054] By using a thermally free-radical polymerizable dry film containing a white inorganic filler and surrounding the side circumferential surfaces of each micro-LED with the hardened product of the dry film, the light emitted from each micro-LED can be reflected, thereby suppressing a decrease in brightness or increasing brightness. In addition, by using a thermally free-radical polymerizable dry film containing a colorant and filling between each micro-LED with the hardened product of the dry film, a partition wall, that is, a light-shielding layer, for preventing the light emitted from adjacent micro-LEDs from being mixed in color can be formed. In particular, since the dry film can follow micro-sized optoelectronic semiconductor elements, it is more suitable as an optoelectronic semiconductor element for micro-LEDs.

[0055] Hereinafter, an example of the process for forming a sealing layer will be described using (a) to (c-2) of Figure 2 below.

[0056] Process (a): Placement process of the dry film

[0057] As shown in an example in (a) of Figure 2 below, the dry film 11 is placed on the substrate 21 having a plurality of optoelectronic semiconductor elements 20. The placement is preferably directly covering the optoelectronic semiconductor elements 20. In addition, in the case of having a release liner, it can be peeled off immediately after placement, or can be peeled off after the pressing process shown below.

[0058] In this specification, if the plurality of optoelectronic semiconductor elements are two or more optoelectronic semiconductor elements, there is no particular limitation. In addition, the emission color of the optoelectronic semiconductor elements is not particularly limited, and examples include red, green, and blue.

[0059] Regarding the size of the optoelectronic semiconductor element, it is preferably 100 μm or less in thickness and 40,000 μm in area when viewed from above. 2 Hereinafter, it is more preferably 50 μm or less in thickness and 10,000 μm in area when viewed from above. 2 Hereinafter, it is further preferably 20 μm or less in thickness and 2,500 μm in area when viewed from above. 2 Hereinafter.

[0060] The distance between the optoelectronic semiconductor elements placed on the substrate is, for example, 10 μm to 5,000 μm. When red, green, and blue optoelectronic semiconductor elements are set as a group and placed on the substrate as one pixel, the distance between the pixels is, for example, 10 μm to 2,000 μm, preferably 20 μm to 1,800 μm, and more preferably 500 μm to 1,500 μm. The distance between the optoelectronic semiconductor elements in one pixel is, for example, 10 μm to 250 μm, preferably 10 μm to 100 μm, and more preferably 20 μm to 60 μm.

[0061] Process (b): Pressing process

[0062] As shown in (b) of Figure 2 , the dry film 11 is made to flow by pressing and filled between a plurality of optoelectronic semiconductor elements. The dry film filled between the plurality of optoelectronic semiconductor elements 20 is thermally cured to become a cured product 11'. The cured product 11' functions as a sealing layer covering the substrate 21 and the optoelectronic semiconductor elements. The pressing method is not particularly limited, and thermal pressing and vacuum pressing are preferred. From the viewpoint of the filling property of the dry film, the temperature during pressing is preferably 20°C to 200°C, more preferably 50°C to 150°C, further preferably 60°C to 130°C, and particularly preferably 80°C to 120°C.

[0063] In order to improve the adhesion to the optoelectronic semiconductor element and the adherend, heat aging may be further performed after pressing. The heating temperature is preferably 80°C to 250°C, and further preferably 100°C to 220°C. The heating time is preferably 30 minutes to 300 minutes, more preferably 60 minutes to 240 minutes, and further preferably 90 minutes to 180 minutes. By setting the heating temperature and heating time as described above, the residual stress of the dry film can be removed, the adhesion surface can be smoothed, and the thermal curing of the dry film forming the sealing layer can be promoted.

[0064] After the pressing process and the heat aging process, the thermally free-radical polymerizable dry film is thermally cured to become a cured product of the dry film (also referred to as a cured product). Through curing, the toughness and durability of the sealing layer are improved, and the adhesion to the adherend is also increased.

[0065] Subsequently, the subsequent step (c) may be carried out as required. Heat aging may also be carried out after the subsequent step (c).

[0066] Step (c): Etching step

[0067] In step (c), etching is carried out to remove or thin the hardened product of the dry film on the optoelectronic device. By removing the hardened product on the optoelectronic device, the brightness of the light-emitting device is increased, and the visibility during light emission is ensured. The thickness of the sealing layer after etching is preferably the same order of magnitude as the thickness of the optoelectronic device as shown in (c-1) below, or below the thickness of the dry film as shown in (c-2) below. In addition, even if the dry film is not completely removed from the light-emitting device, it is sufficient as long as it is substantially removed, and it may be in a state where some thin films remain. In addition, when the brightness of the light-emitting device is sufficiently ensured, the etching step may not be carried out. Figure 2 as shown in (c-1) below, the same order of magnitude as the thickness of the optoelectronic device, or as shown in Figure 2 below (c-2) is below the thickness of the dry film. In addition, even if the dry film is not completely removed from the light-emitting device, it is sufficient as long as it is substantially removed, and it may be in a state where some thin films remain. In addition, when the brightness of the light-emitting device is sufficiently ensured, the etching step may not be carried out.

[0068] The etching method is not particularly limited, and preferred examples include wet etching methods such as chemical polishing using a chemical agent, or physical polishing using an abrasive, laser etching, plasma etching using argon plasma or oxygen plasma, and dry etching methods such as ion beam etching. From the viewpoint of reducing surface irregularities, it is preferable to use a combination of a wet etching method and a dry etching method.

[0069] In addition, it may be physical etching such as plasma treatment. As the etching conditions, for example, as long as a mixed gas of CF4 / O2 / N2 is used in an anisotropic plasma device, dry etching may be carried out under the conditions of a power of 1500 W to 3000 W and 180 seconds to 600 seconds. At this time, as the gas supply amount of CF4, for example, it may be 50 sccm to 100 sccm, as the gas supply amount of O2, for example, it may be set to 500 sccm to 1000 sccm, and as the gas supply amount of N2, for example, it may be set to 50 sccm to 100 sccm.

[0070] <Dry film>

[0071] The dry film contains a free-radical polymerizable organic compound and a thermal free-radical polymerization initiator.

[0072] The thickness of the dry film is preferably, for example, 0.5 μm to 100 μm, more preferably 1 μm to 50 μm. By being within the above range, the sealing property of the dry film becomes excellent. The dry film may be a single layer or a laminate of two or more layers, and the thickness can be measured by the method described in the following examples.

[0073] Dry films require various optical properties depending on their uses. For example, in the case of uses that require high transparency, high transparency can be achieved by not using colorants. Additionally, in the case of uses that require light-shielding properties, light-shielding properties can be imparted by using black colorants. Further, in the case of uses that require reflectivity, reflectivity can be imparted by using white colorants. Moreover, in the case of uses that require a high refractive index, the refractive index can be changed to a high refractive index by using inorganic fillers with a high refractive index.

[0074] In addition, the optical properties can be measured by the methods described in the examples below.

[0075] When the dry film contains a colorant, the higher the light-shielding property of the dry film mainly based on so-called photopolymerization, the more difficult it is for light to reach the inside of the dry film, and the more likely it is to generate unhardened parts. However, the dry film of the present disclosure is polymerized by heat, so it is hardened uniformly inside, and unhardened parts are not likely to remain inside the dry film. Therefore, it is possible to ensure higher light-shielding properties while hardening uniformly.

[0076] When the dry film does not contain a colorant, the transparency of the dry film mainly based on so-called photopolymerization is likely to decrease mainly due to yellowing caused by the remaining photoinitiator for free radical polymerization. On the other hand, since the dry film of the present disclosure uses a thermal radical polymerization initiator, it is not likely to yellow. Therefore, it is possible to ensure higher transparency while hardening.

[0077] In addition, for dry films mainly based on so-called thermal crosslinking reactions, the transparency is likely to decrease mainly due to foaming caused by gas generation during the reaction of crosslinking agents such as isocyanates and remaining in the dry film. On the other hand, since the dry film of the present disclosure uses a thermal radical polymerization initiator, it is not likely to generate gas and can ensure higher transparency. Moreover, the transparency can be measured by the methods described in the examples below.

[0078] The storage elastic modulus (G'80) at 80 °C obtained by dynamic viscoelasticity measurement of the dry film is preferably 5×10 4 Pa to 5×10 7 Pa, more preferably 10×10 4 Pa to 1×10 7 Pa, and even more preferably 50×10 4 Pa to 5×10 6 Pa. By setting G'80 to 5×10 4 Pa or more, in the pressing process of sealing the optoelectronic semiconductor element, the pressure applied to the dry film is likely to spread evenly. By setting G'80 to 5×10 7Below Pa, it is easy to closely adhere to the optoelectronic semiconductor element, and the sealing property of the optoelectronic semiconductor element becomes excellent. G'80 is a value measured under the conditions of a shear mode and 1 Hz to 10 Hz, and can be measured by the method described in the following examples.

[0079] By adjusting G'80 to the above range, the dry film can exhibit excellent fluidity in the pressing process.

[0080] In addition, G'80 of the present disclosure can be adjusted by the type, composition or content of the radically polymerizable organic compound, and the content of the thermal radical polymerization initiator. In the case where the radically polymerizable polymer (a) is contained as the radically polymerizable organic compound, G'80 can be reduced by increasing the content of the compound having a low weight average molecular weight and / or the compound having a low glass transition temperature. In the case where it is desired to increase G'80, the opposite adjustment can be made. In the case where the radically polymerizable oligomer (b) and / or the radically polymerizable monomer (c) is contained as the radically polymerizable organic compound, G'80 can be reduced by increasing the content of the compound having a low viscosity. In the case where it is desired to increase G'80, the opposite adjustment can be made. In addition, G'80 can be increased by increasing the content of the thermal radical polymerization initiator. In the case where it is desired to reduce G'80, the opposite adjustment can be made.

[0081] The loss tangent tanδ80 at 80 °C obtained by dynamic viscoelasticity measurement of the dry film is preferably 0.3 to 0.7, more preferably 0.4 to 0.6. By setting tanδ80 to 0.3 or more, the pressure applied to the dry film is easily diffused uniformly in the pressing process for sealing the optoelectronic semiconductor element. By setting tanδ80 to 0.7 or less, it is easy to closely adhere to the optoelectronic semiconductor element, and the sealing property of the optoelectronic semiconductor element becomes excellent. tanδ80 can be measured by the same method as G'80.

[0082] By adjusting tanδ80 to 0.3 to 0.7, the pressure diffusibility of the dry film can be improved in the pressing process.

[0083] The tanδ80 can be adjusted by the type, composition or content of the radically polymerizable organic compound and the content of the thermal radical polymerization initiator. When the radically polymerizable polymer (a) is contained as the radically polymerizable organic compound, the tanδ80 can be decreased by increasing the content of the compound having a low weight average molecular weight and / or the compound having a low glass transition temperature, and when it is desired to increase the tanδ80, the adjustment can be made conversely. When the radically polymerizable oligomer (b) and / or the radically polymerizable monomer (c) is contained as the radically polymerizable organic compound, the tanδ80 can be decreased by increasing the content of the compound having a low viscosity, and when it is desired to increase the tanδ80, the adjustment can be made conversely. Further, the tanδ80 can be increased by increasing the content of the thermal radical polymerization initiator, and when it is desired to decrease the tanδ80, the adjustment can be made conversely.

[0084] The kinetic friction coefficient of the surface of the dry film is preferably 0.5 or less, more preferably 0.4 or less, and still more preferably 0.35 or less. By setting the kinetic friction coefficient to 0.5 or less, the flow of the dry film at the contact surface between the optical semiconductor element and the dry film becomes good in the pressing step of sealing the optical semiconductor element, and the sealing property of the optical semiconductor element becomes excellent. Further, when an adherend such as an optical semiconductor element is adhered to the dry film, air bubbles hardly enter and the transparency becomes excellent.

[0085] In addition, the lower limit of the kinetic friction coefficient is 0 or more, and the closer to 0, the more preferable. The kinetic friction coefficient can be measured, for example, by the method described in the examples below.

[0086] The kinetic friction coefficient can be adjusted by the type, composition or content of the radically polymerizable organic compound and the content of the thermal radical polymerization initiator. When the radically polymerizable polymer (a) is contained as the radically polymerizable organic compound, the kinetic friction coefficient can be decreased by increasing the content of the compound having a high glass transition temperature, and when it is desired to increase the kinetic friction coefficient, the adjustment can be made conversely. When the radically polymerizable oligomer (b) and / or the radically polymerizable monomer (c) is contained as the radically polymerizable organic compound, the kinetic friction coefficient can be decreased by increasing the content of the compound having a low viscosity, and when it is desired to increase the kinetic friction coefficient, the adjustment can be made conversely. Further, the kinetic friction coefficient can be decreased by increasing the content of the thermal radical polymerization initiator.

[0087] <Radically Polymerizable Organic Compound>

[0088] A radically polymerizable organic compound is an organic compound containing a radically polymerizable group that is polymerized and / or crosslinked to a high molecular weight by applying activation energy in the presence of a thermal radical polymerization initiator. By using the radically polymerizable organic compound, the shrinkage force during thermal curing is adjusted, and the sealing property and low-temperature curability become suitable. The radically polymerizable group is, for example, a functional group having an unsaturated double bond such as a (meth)acryloyl group, an N-vinyl group, a vinyl ether group, an allyl group, an unsaturated carboxylic acid group, etc. The radically polymerizable organic compound has at least 1 or more radically polymerizable groups in one molecule, preferably 2 or more, and more preferably 3 or more polyfunctional compounds. Thereby, a crosslinked structure of the molecule is easily obtained, and the low-temperature curability is improved.

[0089] Among the radically polymerizable organic compounds, a compound having a (meth)acryloyl group is preferred because it is easy to synthesize, obtain, and handle. In addition, it is also preferred from the viewpoint of transparency. Examples include: epoxy (meth)acrylate, urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, and (meth)acrylate of alcohols.

[0090] Epoxy (meth)acrylate is, for example, an acrylate obtained by reacting a known aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, etc. with (meth)acrylic acid.

[0091] Preferred compounds as urethane (meth)acrylate are (meth)acrylates obtained by reacting one or two or more hydroxyl group-containing polyesters or hydroxyl group-containing polyethers with a hydroxyl group-containing (meth)acrylate and isocyanates, or (meth)acrylates obtained by reacting a hydroxyl group-containing (meth)acrylate with isocyanates, etc.

[0092] Preferred compounds as the hydroxyl group-containing polyester can be exemplified by hydroxyl group-containing polyesters obtained by reacting one or two or more polyols with one or two or more polyacids. As aliphatic polyols, for example, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, polypropylene glycol, polybutylene glycol, trimethylolpropane, glycerin, pentaerythritol, dipentaerythritol, etc. can be cited. As polyacids, for example, adipic acid, terephthalic acid, phthalic anhydride, trimellitic anhydride, etc. can be cited.

[0093] Preferred compounds as the hydroxyl group-containing polyether can be exemplified by hydroxyl group-containing polyethers obtained by adding one or two or more alkylene oxides to a polyol. As the polyol, the same compounds as those described above can be exemplified. As the alkylene oxide, for example, ethylene oxide, propylene oxide, butylene oxide can be cited.

[0094] Preferred compounds as hydroxy group-containing (meth)acrylates include hydroxy group-containing (meth)acrylates obtained by the esterification reaction of a polyol and (meth)acrylic acid. As the polyol, the same compounds as those of the above-mentioned compounds can be exemplified.

[0095] Among the hydroxy group-containing (meth)acrylates, hydroxy group-containing (meth)acrylates obtained by the esterification reaction of a diol and (meth)acrylic acid are particularly preferred. As a specific example, 2-hydroxyethyl (meth)acrylate can be cited.

[0096] As isocyanates, compounds having at least one or more isocyanate groups in the molecule are preferred, and divalent isocyanate compounds such as toluene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate are particularly preferred.

[0097] Preferred compounds as polyester (meth)acrylates are polyester (meth)acrylates obtained by reacting a hydroxy group-containing polyester with (meth)acrylic acid. Preferred compounds as the hydroxy group-containing polyester used herein include hydroxy group-containing polyesters obtained by the esterification reaction of one or more polyols and one or more monocarboxylic acids and polycarboxylic acids. As the polyol, the same compounds as those of the above-mentioned compounds can be exemplified. As the monocarboxylic acid, for example, formic acid, acetic acid, butyric acid, and benzoic acid can be cited. As the polycarboxylic acid, for example, adipic acid, terephthalic acid, phthalic anhydride, and trimellitic anhydride can be cited.

[0098] Preferred compounds as polyether (meth)acrylates are polyether (meth)acrylates obtained by reacting a hydroxy group-containing polyether with (meth)acrylic acid. Preferred compounds as the hydroxy group-containing polyether used herein include hydroxy group-containing polyethers obtained by adding one or more alkylene oxides to a polyol. As the polyol, the same compounds as those of the above-mentioned compounds can be exemplified. As the alkylene oxide, for example, ethylene oxide, propylene oxide, and butylene oxide can be cited.

[0099] Compounds preferably used as (meth)acrylates of alcohols are (meth)acrylates obtained by reacting an aromatic or aliphatic alcohol having at least 1 hydroxyl group in the molecule and its alkylene oxide adduct with (meth)acrylic acid. Specifically, examples include: 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, isopentyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isooctyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, isobornyl (meth)acrylate, benzyl (meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ε-caprolactone-modified dipentaerythritol hexa(meth)acrylate.

[0100] The radically polymerizable organic compound is preferably one containing a radically polymerizable polymer (a). Alternatively, it is preferably one containing at least one of a radically polymerizable oligomer (b) and a radically polymerizable monomer (c).

[0101] The content of the radically polymerizable organic compound is preferably 10% by mass to 98% by mass, more preferably 40% by mass to 95% by mass, and still more preferably 60% by mass to 90% in 100% by mass of the total solid content of the dry film. By setting the content as described above, the sealing property and low-temperature curability can be suitably adjusted.

[0102] <Radically polymerizable polymer (a)>

[0103] The radically polymerizable polymer (a) (hereinafter, also referred to as polymer (a)) is an organic compound containing the radically polymerizable group and is a high molecular compound having a weight average molecular weight (Mw) of 10,000 or more and 1,000,000 or less. The upper limit of Mw of polymer (a) is preferably 1,000,000, more preferably 500,000, still more preferably 300,000, and even more preferably 200,000. The lower limit of Mw of polymer (a) is more preferably 10,000, still more preferably 20,000, and even more preferably 30,000.

[0104] By including such a polymer (a), the film-forming property of the dry film can be improved.

[0105] Furthermore, by using a part of the polymer (a) as a dispersant for the inorganic filler or the colorant, the uniform dispersibility of the inorganic filler or the colorant in the dry film can be improved.

[0106] The glass transition temperature of the radically polymerizable polymer (a) is preferably -50°C or higher and 90°C or lower, more preferably -15°C or higher and 65°C or lower, and particularly preferably 0°C or higher and 50°C or lower. By being within the above range, a dry film with good sealing performance can be produced. The glass transition temperature is measured by the method described in the examples below.

[0107] Preferably, the radically polymerizable polymer (a) is contained in an amount of 95% by mass or more based on 100% by mass of the radically polymerizable organic compound, and the glass transition temperature thereof is -50°C or higher and 90°C or lower. The radically polymerizable polymer (a) preferably contains a radically polymerizable acrylic polymer, more preferably contains 95% by mass or more of the radically polymerizable acrylic polymer, and further preferably contains 97% by mass or more, and may also be 100% by mass. The glass transition temperature of the radically polymerizable acrylic polymer is more preferably -50°C or higher and 90°C or lower. In addition, the radically polymerizable acrylic polymer described herein refers to a polymer containing structural units derived from acrylic monomers such as (meth)acrylic acid, (meth)acrylate, acrylonitrile, etc. as main structural units. The so-called main structural units herein refer to structural units containing more than 90% by mass of structural units derived from acrylic monomers in 100% by mass of the polymer. The structural units derived from acrylic monomers are preferably 93% by mass or more, more preferably 95% by mass or more, further preferably 97% by mass or more, and may also be 100% by mass.

[0108] In 100% by mass of the total solid content of the dry film, the lower limit of the content rate of the radically polymerizable polymer (a) is preferably 10% by mass, more preferably 40% by mass, and further preferably 60% by mass. The upper limit of the content rate is preferably 99.9% by mass, more preferably 98% by mass, further preferably 95% by mass, and further more preferably 90% by mass. By setting the content rate as such, the sealing performance and the low-temperature curability can be appropriately adjusted.

[0109] <Radically polymerizable oligomer (b)>

[0110] The radically polymerizable oligomer (b) (hereinafter, also referred to as oligomer (b)) is a polymer having structural units of 2 to 100 monomers containing a radically polymerizable group, and is liquid at normal temperature and pressure. In addition, it is a compound having a weight average molecular weight of 100 or more and less than 10,000.

[0111] The weight average molecular weight is more preferably 300 or more and 8,000 or less, still more preferably 400 or more and 6,000 or less, and particularly preferably 500 or more and 4,500 or less. By setting it within the above range, the fluidity of the dry film can be improved and the sealing property can be enhanced.

[0112] Normal temperature in the present disclosure is 25 °C and normal pressure is 1 atmosphere.

[0113] The content rate of the oligomer (b) is preferably 0.1 mass% to 70 mass% in 100 mass% of the total solid content of the dry film, more preferably 1 mass% to 50 mass%, still more preferably 10 mass% to 50 mass%, and particularly preferably 30 mass% to 50 mass%. By setting it within the above content rate, the sealing property, low-temperature curability, and workability can be appropriately adjusted.

[0114] <Free radical polymerizable monomer (c)>

[0115] The so-called free radical polymerizable monomer (c) (hereinafter, also referred to as monomer (c)) is a compound having a free radical polymerizable group which is the smallest structural unit for forming an oligomer or a polymer, and is liquid at normal temperature and normal pressure. The monomer can be a monofunctional monomer or a polyfunctional monomer.

[0116] In particular, from the aspect of easy handling, a (meth)acrylate compound can be preferably used. From the viewpoint of the sealing property, it is preferably a difunctional to hexafunctional (meth)acrylate monomer, and more preferably a difunctional to trifunctional (meth)acrylate monomer.

[0117] The content rate of the monomer (c) is preferably 0.01 mass% to 70 mass% in 100 mass% of the total solid content of the dry film, more preferably 0.1 mass% to 50 mass%, still more preferably 1 mass% to 30 mass%, and particularly preferably 1 mass% to 10 mass%. By setting it within the above content rate, the sealing property and low-temperature curability can be appropriately adjusted.

[0118] The free radical polymerizable organic compound is preferably either the free radical polymerizable oligomer (b) or the free radical polymerizable monomer (c), and can also contain both.

[0119] When the dry film contains the oligomer (b) or the monomer (c), from the viewpoint of the workability of the dry film, for the purpose of suppressing stickiness, it is preferably to contain the binder resin described later.

[0120] Relative to 100 parts by mass of the oligomer (b) and the monomer (c), the binder resin preferably contains 30 parts by mass or more, and more preferably contains 50 parts by mass or more. By being within the above range, a dry film having both sealing property and low-temperature curability and good workability can be prepared.

[0121] <Thermal free radical polymerization initiator>

[0122] The 10-hour half-life temperature of the thermal free radical polymerization initiator is 60 °C or higher and 170 °C or lower. By setting the temperature to 60 °C or higher, the storage stability of the dry film can be maintained, and good sealing performance can be maintained even after long-term storage. In addition, rapid polymerization (hardening) due to hot pressing during sealing can be prevented, and good sealing performance can be exhibited. From these viewpoints, the lower limit of the 10-hour half-life temperature is more preferably 80 °C, and further preferably 100 °C. By setting the temperature to 170 °C or lower, the thermal hardening temperature of the dry film can be reduced, and the hardening time can be shortened, so that low-temperature hardening property can be improved. From the above viewpoints, the upper limit of the 10-hour half-life temperature is more preferably 160 °C, and further preferably 150 °C.

[0123] The 10-hour half-life temperature is the temperature at which the initiator concentration of the thermal free radical polymerization initiator is halved after 10 hours by thermal decomposition. Specifically, for the free radicals of the thermal free radical polymerization initiator, an inert solvent is used to prepare a solution of the thermal free radical polymerization initiator, which is sealed in a glass tube purged with nitrogen. It is immersed in a constant temperature layer set at a specified temperature for 10 hours to cause thermal decomposition, and the amount of the remaining thermal free radical polymerization initiator is measured. By performing the above series of operations at several temperatures, the 10-hour half-life temperature can be obtained from the drawn straight line.

[0124] When the adherend contains precision components, it is sometimes required to lower the manufacturing process temperature. If the sealing process of the dry film and the aging temperature when forming a hardened product can be lowered, the versatility of the dry film can be particularly improved. In addition, the selection range of micro-LEDs, substrates, etc. can be greatly increased. Furthermore, it is also ideal from the viewpoint of energy saving. The inventors have repeatedly made intensive studies and found that by using a peroxide-based thermal free radical polymerization initiator with a 10-hour half-life temperature of 60 °C to 120 °C, a dry film with excellent optical properties, sealing performance, low-temperature hardening property, appearance after hardening, storage stability, and operability can be obtained. From the viewpoint of appearance, the 10-hour half-life temperature of the peroxide-based thermal free radical polymerization initiator is more preferably 70 °C to 115 °C, further preferably 75 °C to 110 °C, and even more preferably 80 °C to 110 °C.

[0125] As the thermal free radical polymerization initiator, an azo thermal polymerization initiator or an organic peroxide polymerization initiator can be used. From the viewpoint of storage stability, an azo thermal polymerization initiator can be suitably used. From the aspect of suppressing foaming during hardening and making the appearance after hardening good, an organic peroxide polymerization initiator can be suitably used. The thermal free radical polymerization initiator adjusts the shrinkage force during thermal hardening, and the sealing performance and low-temperature hardening property become suitable.

[0126] As an organic peroxide polymerization initiator with a half-life temperature of 60 °C or higher and 170 °C or lower for 10 hours, examples include dialkyl peroxides such as di-tert-amyl peroxide (123 °C), di-tert-butyl peroxide (129 °C), di-tert-hexyl peroxide (116 °C), diisopropylbenzene peroxide (116 °C), tert-butyl cumyl peroxide (120 °C), α,α'-bis(tert-butylperoxy-m-isopropyl)benzene (119 °C), 2,5-dimethyl-2,5-bis(tert-butylperoxy)hex-3-yne (131 °C), 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane (120 °C), etc.;

[0127] tert-amyl peroxyacetate (100 °C), tert-butyl peroxyacetate (102 °C), tert-amyl peroxybenzoate (100 °C), tert-butyl peroxybenzoate (104 °C), tert-hexyl peroxybenzoate (99 °C), tert-amyl peroxy-2-ethylhexanoate (75 °C), tert-butyl peroxy-2-ethylhexanoate (72 °C), tert-hexyl peroxy-2-ethylhexanoate (70 °C), 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate (65 °C), tert-butyl peroxy-3,5,5-trimethylhexanoate (97 °C), tert-butyl peroxyisobutyrate (75 °C), tert-amyl peroxyisononanoate (96 °C), tert-butyl peroxyisononanoate (102 °C), tert-butyl peroxylaurate (98 °C), n-butyl 4,4-di-(tert-butylperoxy)valerate (105 °C), 2,5-dimethyl-2,5-di(benzoylperoxy)hexane (100 °C), 2,5-dimethyl-2,5-di-2-ethylhexanoylperoxyhexane (66 °C), etc. peroxyesters;

[0128] Peroxyketals such as 2,2-bis(tert-butylperoxy)butane (103 °C), 2,2-bis(4,4-di-tert-butylperoxycyclohexyl)propane (95 °C), 1,1-bis(tert-amylperoxy)cyclohexane (93 °C), 1,1-bis(tert-butylperoxy)cyclohexane (97 °C), 1,1-bis(tert-hexylperoxy)cyclohexane (87 °C), butyl 4,4-bis(tert-butylperoxy)valerate, etc.;

[0129] Hydroperoxides such as tert-amyl hydroperoxide (165 °C), cumene hydroperoxide (158 °C), p-menthane hydroperoxide (128 °C), diisopropylbenzene hydroperoxide (145 °C), 1,1,3,3-tetramethylbutyl hydroperoxide (153 °C), etc.;

[0130] Diacyl peroxides such as dibenzoyl peroxide (73 °C), diisononanoyl peroxide (61 °C), dilauroyl peroxide (64 °C), disuccinic peroxide (66 °C), etc.;

[0131] tert-Butyl peroxy isopropyl carbonate (99 °C), tert-amyl peroxy isopropyl carbonate (96 °C), tert-hexyl peroxy isopropyl carbonate (95 °C), tert-butyl peroxy-2-ethylhexyl carbonate (99 °C), tert-amyl peroxy-2-ethylhexyl carbonate (99 °C), and other peroxycarbonates, but not limited to these.

[0132] From the viewpoint of storage stability, dialkyl peroxides are preferred, and di-tert-butyl peroxide and tert-butyl peroxybenzoate are more preferred.

[0133] Examples of azo thermal polymerization initiators having a 10-hour half-life temperature of 60 °C or higher and 170 °C or lower include: 2,2'-azobisisobutyronitrile (65 °C), 2,2'-azobis(2-methylbutyronitrile) (68 °C), and other 2,2'-azobisbutyronitriles;

[0134] 1,1'-azobis(cyclohexane-1-carbonitrile) (88 °C) and other 1,1'-azobis-1-alkanitriles;

[0135] 2,2'-azobis(N-butyl-2-methylpropionamide) (110 °C) and other 2,2'-azobispropionamides;

[0136] And dimethyl 1,1'-azobis(1-cyclohexanecarboxylate) (73 °C), dimethyl 2,2'-azobis(2-methylpropionate) (66 °C), 2,2'-azobis(2,4,4-trimethylpentane) (110 °C), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] (61 °C), 2,2'-azobisisobutyrate, 1,1'-azobis(acetoxy-1-phenylethane), etc.

[0137] In addition, examples of azo compounds having a carboxyl group or a hydroxyl group include 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide), etc., but not limited to these.

[0138] From the viewpoint of storage stability, 2,2'-azobispropionamides are preferred, and 2,2'-azobis(N-butyl-2-methylpropionamide) is more preferred.

[0139] The thermal free radical polymerization initiator is preferably contained in an amount of 0.01% to 20% by mass, more preferably 0.1% to 18% by mass, still more preferably 0.8% to 16% by mass, still more preferably 1% to 13% by mass, and particularly preferably 4.4% to 13% by mass based on 100% by mass of the total solid content of the dry film. By setting it to 0.01% to 20% by mass, in the case of transparent applications, the transparency of the cured product of the dry film is excellent. In addition, by setting it to 0.01% by mass or more, the low-temperature curability and workability are excellent, and by setting it to 20% by mass or less, the storage stability is excellent.

[0140] For the same reason as described above, the blending amount of the peroxide-based thermal free radical polymerization initiator is preferably contained in an amount of 0.01% to 20% by mass, more preferably 0.1% to 18% by mass, still more preferably 0.8% to 16% by mass, still more preferably 1% to 13% by mass, and particularly preferably 4.4% to 13% by mass in the total solid content of the dry film.

[0141] In addition, from the viewpoint of storage stability, the thermal free radical polymerization initiator is preferably not used in combination with the photo free radical polymerization initiator.

[0142] <Other Components>

[0143] In the dry film of the present disclosure, other components may also be contained within the range that does not impair the object of the present disclosure. For example, a colorant, an inorganic filler, a dispersant, an adhesive resin, a silane coupling agent, etc. may be added.

[0144] <Colorant (Q)>

[0145] As the colorant (Q) for the purpose of forming a reflective layer, for example, titanium oxide, zinc oxide, lithopone, etc. can be used. From the viewpoint of whiteness, a white pigment is preferred, and among them, from the viewpoint of dispersibility, titanium oxide is preferred. By using a white pigment, the dry film is made white, and the space between or around multiple micro LEDs is sealed, and the sealing layer functions as a reflective layer, which can further improve the brightness of the micro LEDs.

[0146] As the titanium oxide used in the present disclosure, known titanium oxides such as rutile-type titanium oxide and anatase-type titanium oxide can be used. From the viewpoint of resin deterioration caused by light, rutile-type titanium oxide is preferred.

[0147] As specific examples of rutile-type titanium oxide, the following can be cited: "Tipaque R-820, R-830, R-930, R-550, R-630, R-680, R-670, R-780, R-850, CR-50, CR-57, CR-80, CR-90, 90-2, CR-93, CR-95, CR-97, CR-63, CR-58, UT771" manufactured by Ishihara Sangyo Co., Ltd.; "Ti-Pure R-101, R-103, R-104, R-105, R-108, R-900, R-902+, R-960, R-706" manufactured by DuPont; "TITONE R-25, R-21, R-32, R-7E, R-5N, R-62N, R-42, R-45M, GTR-100, D-918" manufactured by Sakai Chemical Industry Co., Ltd., etc.

[0148] The arithmetic mean particle diameter of the rutile-type titanium oxide is preferably 0.1 μm to 1.5 μm, more preferably 0.15 μm to 1.1 μm. By setting the arithmetic mean particle diameter to 0.1 μm or more, aggregation and precipitation of titanium oxide in the coating liquid for dry film are easily prevented. In addition, by setting the arithmetic mean particle diameter to 1.5 μm or less, whiteness is improved and high reflectance performance is exhibited. Further, when the particle shape of the colorant (Q) has an average aspect ratio (major axis length / minor axis length) of 1.5 or more, the arithmetic mean particle diameter is obtained by averaging the major axis lengths. In addition, the arithmetic mean particle diameter of the colorant (Q) can be determined from an image obtained by observing about 20 primary particles in an image obtained by magnifying a transmission electron microscope (TEM) about 50,000 to 1,000,000 times.

[0149] Regarding the blending amount of the white pigment, it is preferably to contain 0.1% by mass to 35% by mass of the colorant (Q) in 100% by mass of the total solid content of the dry film. The lower limit of the blending amount is more preferably 0.5% by mass, further preferably 1% by mass, and still more preferably 5% by mass. The upper limit of the blending amount is more preferably 30% by mass, further preferably 28% by mass, and particularly preferably 20% by mass. By setting the content to 0.1% by mass to 35% by mass, a dry film with good reflectivity, sealing property, and workability can be obtained.

[0150] When forming a light-shielding layer, the colorant (Q) is preferably a black colorant (such as pigment, dye, etc.). Specifically, examples include: carbon black, graphite, copper oxide, manganese dioxide, aniline black, perylene black, titanium black, cyanine black, activated carbon, ferrite (non-magnetic ferrite, magnetic ferrite, etc.), magnetite, chromium oxide, iron oxide, molybdenum disulfide, chromium complex, anthraquinone-based colorant, zirconium nitride, etc. The black colorants can be used alone or in combination of two or more. In addition, colorants obtained by combining colorants that exhibit colors other than black and functioning as black colorants can also be used.

[0151] Among the colorants (Q), carbon black is particularly preferred in terms of dispersibility and light-shielding property in the radically polymerizable organic compound. The carbon black that can be used is the carbon black commonly used for black colorant applications. As the carbon black, one or more of known carbon blacks such as channel black, furnace black, thermal black, lamp black, acetylene black, etc. can be used. In addition, resin-coated carbon black can also be used. Furthermore, carbon nanofibers and carbon nanotubes can also be used.

[0152] When blending carbon black into the dry film, carbon black powder or a carbon black dispersion can be added.

[0153] From the viewpoint of light-shielding property, the average particle diameter of carbon black is preferably 10 nm or more and 500 nm or less, more preferably 10 nm or more and 300 nm or less, and still more preferably 10 nm or more and 100 nm or less. In addition, the average particle diameter is the arithmetic average primary particle diameter obtained by observing with an electron microscope.

[0154] From the viewpoint of dispersibility, the carbon black preferably has a specific surface area of 50 m 2 / g to 400 m 2 / g, a volatile component of 0.1 wt% to 10 wt%, and a pH value of 2 to 10. More preferably, the pH is 3 to 8, and still more preferably, the pH is 3 to 6.

[0155] Regarding the blending amount of the colorant (Q), in 100 mass% of the total solid content of the dry film, from the viewpoint of exerting the characteristics of the colorant (Q), it is preferably set to 0.1 mass% or more. The lower limit of the blending amount of the colorant (Q) is more preferably 0.5 mass%, still more preferably 1 mass%, and still more preferably 5 mass%. The upper limit of the blending amount of the colorant (Q) is, for example, 80 mass%, 40 mass%, etc. From the viewpoint of obtaining a dry film with good light-shielding property, sealing property, and operability, the upper limit is preferably 35 mass%, more preferably 32 mass%, more preferably 30 mass%, still more preferably 28 mass%, and still more preferably 20 mass%.

[0156] <Inorganic filler>

[0157] The dry film may also contain inorganic fillers other than those described above (hereinafter simply referred to as inorganic fillers). Examples of such inorganic fillers include silica such as amorphous silica, crystalline silica, fused silica, spherical silica, alumina, titanium oxide, antimony trioxide, magnesium oxide, tin oxide, zirconium oxide, magnesium hydroxide, barium sulfate, barium titanate, calcium carbonate, talc, clay, Nopcosperse silica particles, boehmite, magnesium carbonate, alumina, aluminum hydroxide, silicon nitride, calcium zirconate, kaolinite, mica, sericite, montmorillonite, bentonite, basic magnesium carbonate, boron nitride, aluminum nitride, titanium nitride and other inorganic compounds. In addition, metal powders such as copper, tin, zinc, nickel, silver, palladium, aluminum, iron, cobalt, gold, platinum can be cited. The inorganic filler is preferably spherical particles. Among them, silica is preferred, which inhibits the curing shrinkage of the cured product of the dry film and improves properties such as adhesion and hardness.

[0158] When imparting high refractive properties to the dry film, it is preferred that the total light transmittance in the visible light range (380 nm to 780 nm) of the dry film is 70% or more and the refractive index is set to 1.47 to 1.56. The total light transmittance is more preferably 80% or more, further preferably 85% or more, further more preferably 90% or more, and particularly preferably 92% or more. The lower limit of the refractive index is more preferably 1.49, and further preferably 1.51. The upper limit of the refractive index is more preferably 1.54, and further preferably 1.53. From the viewpoint of adjusting the refractive index, inorganic fillers such as alumina, titanium oxide, and zirconium oxide can also be added. In addition, the total light transmittance is the ratio of the total amount of transmitted light passing through the cured layer to the total amount of incident light incident on the cured layer, and the cured layer is obtained by heat-treating the dry film at 130 °C for 120 minutes.

[0159] From the viewpoint of dispersibility, the specific surface area of the inorganic filler obtained by the BET method is preferably 5 m 2 / g to 400 m 2 / g, more preferably 10 m 2 / g to 150 m 2 / g, and further preferably 20 m 2 / g to 90 m 2 / g.

[0160] The average primary particle diameter (hereinafter referred to as particle diameter) of the inorganic filler is preferably 1nm to 1200nm. By setting the particle diameter to more than 1nm, it is easy to maintain the viscosity of the resin composition at a level suitable for coating. In addition, by setting the particle diameter to less than 1200nm, the coating film resistance is improved. The particle diameter of the inorganic filler is more preferably 5nm to 1000nm, and further preferably 10nm to 700nm, and particularly preferably 50nm to 300nm. The particle diameter of the inorganic filler can be obtained based on the average value of about 20 primary particles observed in the image obtained by magnifying 50,000 to 1,000,000 times by a transmission electron microscope (TEM). In the case where the particle shape of the inorganic filler has an average aspect ratio (major axis length / minor axis length) of more than 1.5, the particle diameter is obtained by averaging the major axis length.

[0161] From the perspective of embedding properties, the content of the inorganic filler (the total content when two or more types are included) is preferably 0.01% by mass to 40% by mass, more preferably 0.1% by mass to 30% by mass, and further preferably 0.5% by mass to 20% by mass, based on the total amount of solid content of the dry film. By including 0.01% by mass to 40% by mass of the inorganic filler, the effect of improving the fluidity of the dry film during the pressing process is easily exhibited, and the embedding properties are improved.

[0162] From the viewpoint of dispersibility, the inorganic filler is preferably surface-modified by a surface modifier. Examples of the surface modifier include organic acids, silane coupling agents, surfactants, titanium coupling agents, and metal impurities, preferably containing organic acids. Surface treatments that do not introduce organic groups, such as aluminum oxide treatment, may also be performed. The surface treatment method of the inorganic filler is not particularly limited, and any known conventional method may be used, as long as the surface of the inorganic filler is treated with a surface treatment agent having a curable reactive group, such as a coupling agent having a curable reactive group as an organic group.

[0163] In terms of adjusting the film-forming property and reflectivity of the sealing layer, the colorant (Q) or the inorganic filler is preferably dispersed in the polymer (a) and used as a dispersion. As the dispersion treatment, any disperser that can be commonly used in mechanical crushing can be used, such as a ball mill, a roll mill, a sand mill, a bead mill, and a nanomizer. Among them, a bead mill is preferably used. As such a disperser, for example, a super mill, a sand grinder, an agitator mill, a grain mill, a dyno-mill, a pearl mill, and a cobol mill (all are trade names) can be cited.

[0164] In the present disclosure, from the viewpoint of the storage stability of the dispersion, it is preferable to use a dispersant in the dispersion treatment of the colorant (Q) or the inorganic filler. In the present disclosure, the dispersant has a function of imparting a repulsive force between particles to prevent the particles divided by the dispersion treatment from aggregating again.

[0165] As the dispersant, known compounds can be used, such as cationic, anionic, or nonionic surfactants, cationic, anionic, or nonionic polymer dispersants, and pigment derivative type dispersants. From the viewpoint of the storage stability of the dispersion, a pigment derivative type dispersant is preferably used.

[0166] The pigment derivative type dispersant is a compound having an acidic group, a basic group, a neutral group, etc. in an organic pigment residue. For example, compounds having acidic substituents such as a sulfo group, a carboxyl group, or a phosphoric acid group and amine salts thereof, compounds having basic substituents such as a sulfonamide group, an amide group, or a terminal tertiary amino group, and compounds having neutral substituents such as a phenyl group or an N-phthalimidylalkyl group can be cited. Organic pigments include, for example, phthalocyanine pigments, diketopyrrolopyrrole pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, perinone pigments, perylene pigments, thiazine indigo pigments, triazine pigments, benzimidazolone pigments, indole pigments such as benzisoindole, isoindoline pigments, isoindolinone pigments, quinophthalone pigments, naphthol pigments, threne pigments, metal complex pigments, and azo pigments such as azo, bisazo, and polyazo pigments.

[0167] By using these pigment dispersants, it is possible to prevent the aggregation over time of the colorant (Q) or the inorganic filler contained in the dry film and maintain good reflectivity.

[0168] When the dry film contains a white colorant, based on the total amount (100% by mass) of the dry film, the content rate of the dispersant (the total content rate in the case of containing two or more kinds) is preferably 0.01% by mass to 35% by mass, more preferably 0.1% by mass to 20% by mass. By containing 0.01% by mass or more of the dispersant, the light reflectivity becomes good, and by being 35% by mass or less, the viscosity of the white resin composition for forming the sealing layer becomes an appropriate range, and the coating adaptability becomes good.

[0169] When the dry film contains a black colorant, based on the total amount (100% by mass) of the dry film, the content rate of the pigment dispersant (the total content rate in the case of containing two or more kinds) is preferably 0.01% by mass to 30% by mass, more preferably 0.1% by mass to 20% by mass. By containing 0.01% by mass or more of the pigment dispersant, the light shielding property becomes good, and by being 30% by mass or less, the viscosity of the black resin composition for forming the sealing layer becomes an appropriate range, and the coating adaptability becomes good.

[0170] When the dry film contains an inorganic filler, based on the total amount of the solid components of the dry film, the content rate of the dispersant is preferably 0.01% by mass to 45% by mass, more preferably 0.1% by mass to 35% by mass, and further preferably 1% by mass to 30% by mass. By containing 0.01% by mass or more of the dispersant, the brightness of the optoelectronic device becomes good, and by being 45% by mass or less, the viscosity of the dispersion becomes an appropriate range, and the coating adaptability becomes good.

[0171] <Adhesive resin>

[0172] The adhesive resin does not contain the radical polymerizable group and is an organic polymer compound different from the radical polymerizable organic compound.

[0173] In addition, the adhesive resin is an organic polymer compound having a glass transition temperature of -50°C or higher and 90°C or lower and a weight average molecular weight of 10,000 or higher and 1,000,000 or lower. The glass transition temperature of the adhesive resin is more preferably -15°C or higher and 50°C or lower, and further preferably 0°C or higher and 25°C or lower, and the weight average molecular weight is more preferably 25,000 or higher and 200,000 or lower, and further preferably 30,000 or higher and 100,000 or lower.

[0174] The binder resin can use known and commonly used thermosetting resins and thermoplastic resins. Specifically, for example, acrylic resins, maleic resins, polybutadiene resins, polyester resins, polyurethane resins, epoxy resins, oxetane resins, phenoxy resins, phenolic resins, alkyd resins, amino resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, fluororesins, butyral resins, styrene-maleic copolymers, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymers, polyvinyl acetate, vinyl-based resins, alkyd resins, polystyrene resins, polyamide resins, rubber-based resins, cyclized rubber-based resins, celluloses, polyethylene (high-density polyethylene (HDPE), low-density polyethylene (LDPE)), polybutadiene, carbodiimide resins, cyclic carbonate compounds, cyclic sulfur resins, and polyimide resins, etc. In particular, acrylic resins, polyurethane resins, and epoxy resins are preferred, and acrylic resins are more preferred.

[0175] By containing the binder resin, the tackiness of the dry film can be adjusted, and the operability of the dry film can be improved.

[0176] Furthermore, in the case of containing a thermosetting resin as the binder resin, in order to promote the formation of a crosslinked structure, it is preferably to contain a curing agent. The curing agent has a plurality of functional groups capable of reacting with the functional groups of the thermosetting resin. Examples of the curing agent include known compounds such as epoxy-based crosslinking agents, acid anhydride group-containing compounds, imidazole compounds, isocyanate compounds, blocked isocyanate compounds, aziridine compounds, and amine compounds. By containing the curing agent, the crosslinking degree of the dry film can be adjusted, and the low-temperature curability can be improved.

[0177] <Silane Coupling Agent>

[0178] The silane coupling agent is a compound in which a hydrolyzable group such as a methoxy group or an ethoxy group and a functional group such as an epoxy group are bonded to an Si atom via an alkylene group. The silane coupling agent has the following function: it acts on both the substrate on which the light-emitting element is placed and the polymer (a), thereby improving the adhesion of the sealing layer.

[0179] Examples of the silane coupling agent include alkoxysilane compounds having (meth)acryloyloxy groups such as 3-(meth)acryloyloxypropyltrimethoxysilane, 3-(meth)acryloyloxypropyltriethoxysilane, 3-(meth)acryloyloxypropyltripropoxysilane, 3-(meth)acryloyloxypropyltributoxysilane, 3-(meth)acryloyloxypropylmethyldimethoxysilane, 3-(meth)acryloyloxypropylmethyldiethoxysilane, and methacryloyloxyoctyltrimethoxysilane;

[0180] Alkoxysilane compounds with vinyl groups such as vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinylmethyldimethoxysilane, vinylmethyldiethoxysilane;

[0181] Alkoxysilane compounds with amino groups such as 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltripropoxysilane, 3-aminopropylmethyldimethoxysilane, 3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane;

[0182] Alkoxysilane compounds with mercapto groups such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyltripropoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropylmethyldiethoxysilane;

[0183] Alkoxysilane compounds with one epoxy group such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltripropoxysilane, 3-glycidoxypropyltributoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane;

[0184] Tetraalkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane;

[0185] 3-chloropropyltrimethoxysilane, n-hexyltrimethoxysilane, n-hexyltriethoxysilane, n-decyltrimethoxysilane, n-decyltriethoxysilane, styryltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, hexamethyldisilazane, silicone resins with alkoxysilyl groups in the molecule, etc.

[0186] From the perspective of adhesion, alkoxysilane compounds are preferred, and 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, and methacryloxyoctyltrimethoxysilane are more preferred.

[0187] Based on the total solid content of the dry film, the content rate of the silane coupling agent is preferably 0.01% by mass to 15% by mass, more preferably 0.05% by mass to 10% by mass, and still more preferably 0.1% by mass to 5% by mass. By setting it to 0.01% by mass to 15% by mass, the adhesion can be appropriately adjusted.

[0188] <Crosslinking component>

[0189] The dry film may contain crosslinking components such as crosslinking agents, hardening accelerators, and hardening retarders. By containing crosslinking components, the mechanical strength or elastic modulus of the cured product of the dry film can be adjusted. In addition, the hardening rate during hot pressing or heat aging in the pressing process can be adjusted.

[0190] The crosslinking agent improves the cohesion of the dry film and the adhesion by undergoing a crosslinking reaction with the reactive functional groups of the polymer (a). The crosslinking agent is preferably a crosslinking agent having a plurality of functional groups capable of reacting with the functional groups of the polymer (a). Suitable examples of the crosslinking agent include: epoxy compounds, aziridine compounds, imidazole compounds, isocyanate compounds, acid anhydride group-containing compounds, and amine compounds. From the viewpoint of adjusting the adhesion between the dry film and the adherend, epoxy compounds, aziridine compounds, imidazole compounds, and isocyanate compounds are preferred, and aziridine compounds are more preferred. The dry film is more preferably a combination of a free-radical polymerizable acrylic polymer and a crosslinking agent capable of undergoing a crosslinking reaction with the reactive functional groups of the free-radical polymerizable acrylic polymer.

[0191] The epoxy compound is a compound having two or more epoxy groups in one molecule and is a compound other than the polymer (a) having a structural unit based on the epoxy group-containing monomer.

[0192] Examples of the epoxy compound include: glycidyl ether type epoxy compounds, glycidyl amine type epoxy compounds, glycidyl ester type epoxy compounds, cyclic aliphatic (alicyclic) epoxy compounds, bisphenol type epoxy compounds, hydrogenated bisphenol type epoxy compounds, etc.

[0193] Examples of the aziridine compound include: trimethylolpropane tris[3-(aziridin-1-yl)propionate], tetramethylolmethane-tris-β-aziridinylpropionate, N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), tris-2,4,6-(1-aziridinyl)-1,3,5-triazine, 4,4'-bis(ethyleneimino carbonylamino)diphenylmethane, etc.

[0194] The isocyanate compound is an isocyanate having two or more isocyanate groups, and is a compound other than the polymer (a) having a structural unit based on the isocyanate group-containing monomer. The isocyanate compound is preferably, for example, an isocyanate monomer such as an aromatic polyisocyanate, an aliphatic polyisocyanate, an araliphatic polyisocyanate, an alicyclic polyisocyanate, and a biuret body, a urate body, and an adduct thereof.

[0195] From the viewpoint of forming a sufficient crosslinked structure, the isocyanate compound is preferably a trifunctional isocyanate compound. The isocyanate compound is more preferably an adduct and a urate body which are reaction products of an isocyanate monomer and a trifunctional low-molecular-weight active hydrogen-containing compound. The isocyanate compound is preferably a trimethylolpropane adduct of hexamethylene diisocyanate, a urate body of hexamethylene diisocyanate, a trimethylolpropane adduct of toluene diisocyanate, a urate body of toluene diisocyanate, a trimethylolpropane adduct of isophorone diisocyanate, a urate body of isophorone diisocyanate, and more preferably a trimethylolpropane adduct of hexamethylene diisocyanate, a trimethylolpropane adduct of toluene diisocyanate, a trimethylolpropane adduct of isophorone diisocyanate.

[0196] Based on the total amount of the solid components of the dry film, the content rate of the crosslinking agent is preferably 0.01% by mass to 20% by mass, more preferably 0.1% by mass to 10% by mass, and still more preferably 0.5% by mass to 5% by mass. By setting it to 0.01% by mass to 20% by mass, the adhesion can be appropriately adjusted. When the crosslinking agent is an epoxy compound, based on the total amount (100% by mass) of the solid components of the dry film, the content rate of the epoxy compound is preferably 0.01% by mass to 10% by mass, more preferably 0.03% by mass to 10% by mass, still more preferably 0.05% by mass to 7% by mass, and particularly preferably 0.1% by mass to 5% by mass. By setting it to 0.01% by mass or more, the adhesion can be appropriately adjusted. By setting it to 10% by mass or less, the insulation can be appropriately adjusted.

[0197] <Method for forming dry film>

[0198] The method for forming the dry film is not particularly limited, and as a suitable example, the following method can be cited: A liquid dry film precursor obtained by adding an arbitrary solvent to the components constituting the dry film is coated, and the solvent is dried to form a dry film. The purpose of adding the solvent is to adjust the viscosity level suitable for coating.

[0199] Known coating machines or methods such as a bevel wheel coater, a die coater, a roll coater, a die lip coater, a reverse coater, an intaglio coater, a bar coater, a curtain coater, dip coating, spin coating, screen printing, and casting can be used during coating. The solvent contained in the dry film precursor can be removed by a drying process after coating.

[0200] As a preferred embodiment, after coating the dry film precursor on a support such as a release liner or a substrate, the coated film can be heated and dried using a hot air oven, an infrared heater, etc., thereby forming a dry film on one side of the support. Furthermore, in order to increase the crosslink density of the dry film, for example, an aging treatment such as standing at a specific temperature condition or irradiation with ultraviolet (UV) light can be performed.

[0201] <Release Liner>

[0202] The release liner supports the dry film and is a film on which the dry film precursor is coated when forming the dry film. As the release liner, for example, polyester films such as polyethylene terephthalate or polyethylene naphthalate, polyimide films, polyamideimide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, polystyrene films, etc., films containing thermoplastic resins, and papers can be used. Among these, polyester films can be suitably used from the viewpoints of heat resistance, mechanical strength, workability, etc. The thickness of the release liner is not particularly limited and can be appropriately selected within a range of approximately 10 μm to 150 μm according to the use. A release treatment can also be performed on the surface of the release liner where the dry film precursor is provided.

[0203] <Protective Film>

[0204] For the purpose of preventing dust and the like from adhering to the surface of the dry film and improving workability, the protective film is preferably provided on the surface of the dry film opposite to the release liner. As the protective film, for example, polyester films such as polyethylene terephthalate or polyethylene naphthalate, polyimide films, polyamideimide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, polystyrene films, etc., films containing thermoplastic resins, and papers can be used. Among these, polyester films can be suitably used from the viewpoints of heat resistance, mechanical strength, workability, etc. The thickness of the protective film is not particularly limited and can be appropriately selected within a range of approximately 10 μm to 150 μm according to the use. An antistatic treatment, an adhesion treatment, a release treatment, or a concavo-convex treatment can also be performed on the surface of the protective film that contacts the dry film. In addition, among the release force (Tl) between the release liner and the dry film and the release force (Th) between the protective film and the dry film, the relationship of Tl < Th is preferably satisfied.

[0205] <Electronic Device>

[0206] In addition to liquid crystal displays, touch panels, etc., the cured product of the dry film is preferably mounted on electronic devices such as notebook personal computers (PCs), mobile phones, smartphones, and tablet terminals.

[0207] [Examples]

[0208] Hereinafter, examples and comparative examples of the present disclosure are shown to specifically illustrate the present disclosure, but the present disclosure is of course not limited to these examples. In addition, hereinafter, unless otherwise specified, "parts" and "%" are all based on mass.

[0209] The values obtained in this example are the values obtained by the following method.

[0210] <Weight-average molecular weight (Mw)>

[0211] Regarding the measurement of Mw, Mw is obtained by using the GPC "LC-GPC system" manufactured by Shimadzu Corporation and converting polystyrene with a known molecular weight as a standard substance.

[0212] Device name: LC-GPC system "Prominence" manufactured by Shimadzu Corporation

[0213] Column: Four GMHXL manufactured by Tosoh Corporation and one HXL-H manufactured by Tosoh Corporation are connected.

[0214] Mobile phase solvent: Tetrahydrofuran

[0215] Flow rate: 1.0 mL / minute

[0216] Column temperature: 40 °C

[0217] <Glass transition temperature>

[0218] The glass transition temperature of resins such as the radically polymerizable polymer (a) is obtained by using Japanese Industrial Standards (JIS)-K7121 (Differential Scanning Calorimetry (DSC) method: heating rate 10 °C / minute). As the measuring device, a differential scanning calorimeter (DSC2500: manufactured by TA Instrument) is used.

[0219] The materials used in the examples and comparative examples are shown below.

[0220] <Radically polymerizable organic compound>

[0221] [Radically polymerizable acrylic polymer (a)-1]

[0222] To 100 parts by mass of Acrydic A-814 (manufactured by DIC Corporation, an acrylic polyol resin with a hydroxyl value of 17.5 mg KOH / g), 15 parts by mass of a solvent (ethyl acetate) was added and stirred. Then, 15 parts by mass of Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resonac Corporation) was added, and the mixture was stirred at 60°C for 24 hours to obtain a radically polymerizable acrylic polymer (a)-1. The glass transition temperature was 85°C.

[0223] [Radically polymerizable acrylic polymer (a)-2]

[0224] To 100 parts by mass of Acrydic A-801P (manufactured by DIC Corporation, an acrylic polyol resin with a hydroxyl value of 50 mg KOH / g), 15 parts by mass of a solvent (ethyl acetate) was added and stirred. Then, 15 parts by mass of Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resonac Corporation) was added, and the mixture was stirred at 60°C for 24 hours to obtain a radically polymerizable acrylic polymer (a)-2. The glass transition temperature was 50°C.

[0225] [Radically polymerizable acrylic polymer (a)-3]

[0226] To 100 parts by mass of Acrydic 44-127 (manufactured by DIC Corporation, an acrylic polyol resin with a hydroxyl value of 70 mg KOH / g), 15 parts by mass of a solvent (ethyl acetate) was added and stirred. Then, 15 parts by mass of Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resonac Corporation) was added, and the mixture was stirred at 60°C for 24 hours to obtain a radically polymerizable acrylic polymer (a)-3. The glass transition temperature was 35°C.

[0227] [Radically polymerizable acrylic polymer (a)-4]

[0228] To 100 parts by mass of Acrydic A-811 (manufactured by DIC Corporation, an acrylic polyol resin with a hydroxyl value of 34 mg KOH / g), 15 parts by mass of a solvent (ethyl acetate) was added and stirred. Then, 15 parts by mass of Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resonac Corporation) was added, and the mixture was stirred at 60°C for 24 hours to obtain a radically polymerizable acrylic polymer (a)-4. The glass transition temperature was 20°C.

[0229] [Free-radical polymerizable acrylic polymer (a)-5]

[0230] To 100 parts by mass of Acrydic 49-394-IM (manufactured by DIC Corporation, an acrylic polyol resin with a hydroxyl value of 25 mg KOH / g), 15 parts by mass of a solvent (ethyl acetate) was added and stirred. Then, 15 parts by mass of Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resonac Corporation) was added, and the mixture was stirred at 60 °C for 24 hours to obtain free-radical polymerizable acrylic polymer (a)-5. The glass transition temperature was 15 °C.

[0231] [Free-radical polymerizable acrylic polymer (a)-6]

[0232] To 100 parts by mass of Acrydic A-817 (manufactured by DIC Corporation, an acrylic polyol resin, a styrene-acrylic copolymer with a hydroxyl value of 60 mg KOH / g), 15 parts by mass of a solvent (ethyl acetate) was added and stirred. Then, 15 parts by mass of Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resonac Corporation) was added, and the mixture was stirred at 60 °C for 24 hours to obtain free-radical polymerizable acrylic polymer (a)-6. The glass transition temperature was 95 °C.

[0233] · Free-radical polymerizable oligomer (b)-1: UNIDIC 17-806 (manufactured by DIC Corporation), an ultraviolet urethane acrylate resin containing isocyanuric acid triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, and isophorone diisocyanate polyurethane. It is liquid at normal temperature and pressure.

[0234] · Free-radical polymerizable monomer (c)-1: Light Acrylate DPE-6A (manufactured by Kyoeisha Chemical Co., Ltd.), dipentaerythritol hexaacrylate. It is liquid at normal temperature and pressure.

[0235] <Thermal free-radical polymerization initiator>

[0236] The thermal free-radical polymerization initiator used is the thermal polymerization initiator described in Table 1. (H) in Table 1 is a photoinitiator, and the others are thermal polymerization initiators. In addition, (A) to (C), (F) are azo-based thermal polymerization initiators, and (D) to (E), (G), (I) to (M) are peroxide-based thermal polymerization initiators.

[0237] [Table 1]

[0238] Table 1

[0239]

[0240] <Silane Coupling Agent>

[0241] (C-1) KBM-502 (manufactured by Shin-Etsu Silicone Co., Ltd.)

[0242] <Inorganic Filler>

[0243] (P-1) PCS-60 (manufactured by Shin Nippon Chemical Co., Ltd.)

[0244] <Colorant (Q)>

[0245] (Q-1) Tipaque CR-97 (manufactured by Ishihara Sangyo Kaisha, Ltd.)

[0246] (Q-2) Mitsubishi Carbon MA100 (manufactured by Mitsubishi Chemical Corporation)

[0247] <Dispersant>

[0248] (D-1) DISPEARBYK 142 (manufactured by BYK Co., Ltd.)

[0249] (D-2) Solsperse 5000 (manufactured by Lubrizol Corporation)

[0250] <Binder Resin>

[0251] · Acrydic A-801P (manufactured by DIC Corporation, isocyanate-cured acrylic resin, hydroxyl value: 50 mg KOH / g) Glass transition temperature: 50 °C

[0252] [Example 1]

[0253] In a 0.45 L container, with respect to 100 parts by mass of the solid content of the radical-polymerizable polymer (a)-1 as the radical-polymerizable organic compound, 20 parts by mass of Mitsubishi Carbon MA100 (manufactured by Mitsubishi Chemical Corporation) as the colorant Q-2 and 200 parts by mass of methyl isobutyl ketone as the solvent were mixed. After pre-dispersion using a disperser, 1300 parts by mass of zirconia beads with a diameter of 1.0 mm were filled, and formal dispersion was carried out for 1 hour using an oscillator (Skandex SK450: manufactured by Fast&Fluid Management Co., Ltd.). The zirconia beads were removed to obtain a black dispersion.

[0254] In the obtained black dispersion, a thermal radical polymerization initiator (A): Vam-110 (manufactured by Fujifilm Wako Pure Chemical Corporation): 5 parts by mass and a diluting solvent (a mixed solvent of methyl ethyl ketone and toluene): 38 parts by mass are sequentially added, and while stirring with a disperser, stirring is continued until it becomes sufficiently uniform to obtain a dry film precursor (1).

[0255] The dry film precursor (1) is coated on the release layer of a release liner (manufactured by Mitsui Chemicals Tohcello, Inc., SP-PET-O3) with a thickness of 75 μm so that the thickness after drying becomes 25 μm, and heat drying is performed using a hot air oven at 80°C to form a dry film, thereby obtaining a dry film having a release liner.

[0256] [Examples 2 to 18, Examples 28 to 43, Comparative Example 1, Comparative Example 2]

[0257] As shown in Tables 2 and 3, the radical polymerizable organic compound, the radical polymerization initiator, and the colorant are changed to the composition ratios in Tables 2 and 3. Except for this, Examples 2 to 18, Examples 28 to 43, Comparative Example 1, and Comparative Example 2 are obtained in the same manner as in Example 1.

[0258] The composition ratios in Tables 4 and 3 are the composition ratios described in terms of the ratio of the active ingredients excluding the solvent.

[0259] [Example 19]

[0260] The radical polymerizable oligomer (b)-1 as a radical polymerizable organic compound: 100 parts by mass of solid content, Mitsubishi Carbon MA100 (manufactured by Mitsubishi Chemical Corporation) as the colorant Q-2: 20 parts by mass, and methyl isobutyl ketone as a solvent: 200 parts by mass are mixed in a 0.45 L container. After pre-dispersing with a disperser, 1300 parts by mass of zirconia beads with a diameter of 1.0 mm are filled, and formal dispersion is performed for 1 hour using an oscillator (Skandex SK450: manufactured by Fast&Fluid Management Co., Ltd.), and the zirconia beads are removed to prepare a black dispersion.

[0261] In the obtained black dispersion, a thermal radical polymerization initiator (A): Vam-110 (manufactured by Fujifilm Wako Pure Chemical Corporation): 5 parts by mass is added, and while stirring with a disperser, stirring is continued until it becomes sufficiently uniform to obtain a dry film precursor (19).

[0262] The dry film precursor (19) was coated on the release layer of a release liner (manufactured by Mitsui Chemicals, Inc., SP-PET-O3) with a thickness of 75 μm so that the thickness after drying would be 25 μm, and heat-dried using a hot air oven at 80°C to form a dry film, thereby obtaining a dry film with a release liner.

[0263] [Examples 20 to 27, Examples 44 to 51, Comparative Example 3, Comparative Example 4]

[0264] The radically polymerizable organic compound, radical polymerization initiator, colorant, and binder resin were changed to the composition ratios shown in Tables 2 and 3. Otherwise, Examples 20 to 27, Examples 44 to 51, Comparative Example 3, and Comparative Example 4 were obtained in the same manner as in Example 19. In addition, the binder resin was added after preparing the dispersed black dispersion.

[0265] <Storage modulus (G'80) and loss tangent (tanδ80) at 80°C>

[0266] The dry film without the release liner was made to have a thickness of 1 mm or more. In addition, it could be coated to a thickness of 1 mm, or dry film layers with a thickness of less than 1 mm could be laminated any number of times and laminated as needed to make the thickness 1 mm or more. For the obtained dry film, using a rheometer (manufactured by TA Instrument, DHR-2) and a φ8 mm measurement probe, the storage modulus G' was measured under the conditions of a strain of 0.1%, a frequency of 1 Hz, and a temperature increase rate of 3°C / min from 50°C to 120°C, and the storage modulus at 80°C (G'80) was determined. In addition, the loss tangent at 80°C (tanδ80) was calculated by dividing the loss modulus G” at 80°C measured simultaneously by G'80.

[0267] <Coefficient of kinetic friction>

[0268] The dry film cut to a width of 40 mm and without the release liner was placed on a friction tester (manufactured by Toyo Seiki Seisaku-sho, Ltd., Friction Tester TR-2), and the coefficient of kinetic friction was calculated according to the measurement method specified in JIS K7125. The measurement was performed 5 times in total, and the average value was calculated and set as the coefficient of kinetic friction of the dry film.

[0269] [Example 101]

[0270] The radical polymerizable acrylic polymer (a)-1 is used as the radical polymerizable organic compound. 5 parts by mass of Luperox 230 (manufactured by Arkema Kishu Co., Ltd.), which is a thermal radical polymerization initiator, 1 part by mass of silane coupling agent C-1, and 38 parts by mass of a diluting solvent (a mixed solvent of methyl ethyl ketone and toluene) are sequentially added to 100 parts by mass of the solid content of (a)-1, and while stirring with a disperser, stirring is continued until it becomes sufficiently uniform to obtain a dry film precursor (1).

[0271] The dry film precursor (1) is coated on the release layer of a 75-μm-thick release liner (manufactured by Mitsui Chemicals Tohcello, Inc., SP-PET-O3) so that the thickness after drying becomes 25 μm, and heat drying is performed using a hot air oven at 80°C to form a dry film. Subsequently, the dry film is covered with SP-PET-O1 (manufactured by Mitsui Chemicals Tohcello, Inc.) as a protective film to obtain a dry film with a release liner and a protective film.

[0272] [Examples 102 to 116, Comparative Example 101]

[0273] As shown in Table 4A, the types of radical polymerizable organic compounds and the types / amounts of radical polymerization initiators are changed, and except for this, Examples 102 to 116 and Comparative Example 101 are obtained in the same manner as in Example 101.

[0274] The composition ratios in Table 4A are the composition ratios described in terms of the ratio of the active ingredients excluding the solvent. In addition, the lower part of the composition in Table 4A is based on 100 mass% of the dry film solid content. The same applies hereinafter.

[0275] [Example 201]

[0276] The radical polymerizable acrylic polymer (a)-1 is used as the radical polymerizable organic compound. 20 parts by mass of zirconia PCS-60 (manufactured by Shin Nippon Chemical Co., Ltd.), which is an inorganic filler P-1, 5 parts by mass of DISPEARBYK 142 as a dispersant D-1, and 200 parts by mass of methyl isobutyl ketone as a solvent are used with respect to 100 parts by mass of the solid content of (a)-1, and they are mixed in a 0.45-L container and pre-dispersed using a disperser. Thereafter, 1300 parts by mass of zirconia beads with a diameter of 1.0 mm are filled, and formal dispersion is performed for 1 hour using an oscillator (Skandex SK450: manufactured by Fast&Fluid Management Co., Ltd.), and the zirconia beads are removed to prepare a high refractive index dispersion.

[0277] 5 parts by mass of Luperox 230 (manufactured by Arkema Kishu Co., Ltd.), which is a thermal radical polymerization initiator, 1 part by mass of silane coupling agent C-1, and 38 parts by mass of a diluting solvent (a mixed solvent of methyl ethyl ketone and toluene) were successively added to the obtained high refractive index dispersion, and stirred simultaneously using a disperser. Then, it was stirred until it became sufficiently uniform to obtain a dry film precursor.

[0278] Thereafter, a dry film with a release liner and a protective film was obtained in the same manner as in Example 101.

[0279] [Examples 202 to 218, Comparative Example 201]

[0280] As shown in Table 5A, the types of radically polymerizable organic compounds and the types / amounts of radical polymerization initiators were changed, and Examples 202 to 218 and Comparative Example 201 were obtained in the same manner as in Example 201 except for this.

[0281] The composition ratios in Table 5A are the composition ratios described in terms of the effective ingredient ratios excluding the solvent.

[0282] [Examples 301 to 318, Comparative Example 301]

[0283] As shown in Table 6A, Tipaque CR-97, which is a colorant Q-1, was used in place of the inorganic filler, and a white dry film precursor was produced in the same manner as in Example 201 except for this, and a dry film with a release liner and a protective film was obtained.

[0284] [Examples 401 to 418, Comparative Example 401]

[0285] As shown in Table 7A, Mitsubishi Carbon MA100, which is a colorant Q-2, was used in place of the inorganic filler, and D-2 was used in place of D-1 as a dispersant, and a black dry film precursor was produced in the same manner as in Example 201 except for this, and a dry film with a release liner and a protective film was obtained.

[0286] <Storage elastic modulus (G'80) and loss tangent (tanδ80) at 80°C>

[0287] Two sets of sheets from which the protective films had been peeled off from the dry films with release liners and protective films were prepared, and the dry films were laminated to each other using a laminator set at 90°C to produce a laminate of release liner / dry film / release liner. One of the release liners was peeled off from the laminate and the dry films were successively laminated to form a dry film with a thickness of 1 mm.

[0288] For the dry film, using a rheometer (manufactured by TA Instrument, model DHR-2) and a φ8 mm measuring probe, the storage modulus (G'80) at 80°C and the loss modulus G” at 80°C were measured under the conditions of a strain of 0.1%, a frequency of 1 Hz, and a heating rate of 3°C / min from -50°C to 150°C, and the loss tangent at 80°C (tanδ80) was calculated.

[0289] <Coefficient of dynamic friction>

[0290] The dry film of each example with a release liner and a protective film was cut into a width of 40 mm, and the protective film was removed. For the exposed surface, the coefficient of dynamic friction was calculated using the same method as in Example 1 under the environment of 25°C.

[0291] <Evaluation items>

[0292] Unless otherwise specified, any evaluation is set as ◎: very good, ○: good, △: practical, and the evaluation that does not reach the target performance is set as ×. The evaluation results of each example and comparative example are shown in Tables 4B, 5B, 6B, and 7B.

[0293] <Optical density>

[0294] For the obtained dry film, the optical density was measured. The optical density was determined using a densitometer (361T desktop transmission densitometer: manufactured by X-RITE). The evaluation criteria are as follows. In addition, this evaluation is only performed on the examples and comparative examples containing colorants. In Examples 1 to 27 and Comparative Examples 1 to 3, the optical density was measured from the exposed dry film surface side. In addition, for the dry film of Examples 401 to 418 and Comparative Example 401 with a release liner and a protective film, the protective film was peeled off, and the optical density was measured from the exposed dry film surface side.

[0295] ◎: The optical density is 3 or more.

[0296] ○: The optical density is 1 or more and less than 3.

[0297] ×: The optical density is less than 1.

[0298] <Transparency 1>

[0299] The dry films of Examples 28 to 51 and Comparative Example 4 were cut into a size of 2.5 cm × 10 cm, the protective film was peeled off, a glass plate (blue plate glass, manufactured by Kawamura Kuzo Shoten Co., Ltd.) with a thickness of 1.1 mm was attached and pressed. Subsequently, for the obtained test pieces, the release liner was peeled off, and a fadeometer U48 (manufactured by Suga Test Instruments Co., Ltd.) was used to conduct a light resistance test for 48 hours using a carbon arc lamp. Subsequently, for the test pieces, a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH8000) was used to measure the haze value and total light transmittance of the dry film. In addition, this evaluation was only conducted on the examples and comparative examples without colorants.

[0300] ◎: The haze is 1% or less and the total light transmittance is 97% or more.

[0301] ○: The haze is 1% or more or the total light transmittance is 97% or less.

[0302] ×: The haze is 1% or more and the total light transmittance is 97% or less.

[0303] <Transparency 2>

[0304] The dry films with release liners and protective films of Examples 101 to 116, Comparative Example 101, Examples 201 to 218, and Comparative Example 201 were cut into a size of 25 mm × 50 mm, the protective film was peeled off, and in the state with the release liner, the exposed dry film surface was placed on a glass plate (blue plate glass, manufactured by Kawamura Kuzo Shoten Co., Ltd.) of 30 mm × 80 mm × 1.1 mm. On the release liner surface, a TPX with a thickness of 50 μm (Opulent X-44B, manufactured by Mitsui Chemicals Tohcello Co., Ltd.) as a buffer material and a vinyl chloride film with a thickness of 2.0 mm (Celeb T, manufactured by Okamoto Co., Ltd.) were sequentially laminated. Furthermore, cardboard was laminated to prevent adhesion. Next, under the conditions of 5 MPa and 100 °C, the substrate surface was pressed from above the test piece for 5 minutes to press it onto the glass. After pressing, the buffer material, cardboard, and release liner were peeled off. For the test pieces, a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH8000) was used to measure the haze value and total light transmittance of the dry film.

[0305] ◎: The haze is 1% or less and the total light transmittance is 97% or more.

[0306] ○: Satisfies any one of the haze being 1% or less or the total light transmittance being 97% or more.

[0307] ×: Does not satisfy the above ◎, ○.

[0308] <Reflectivity>

[0309] A test piece was produced using the same method as the transparency evaluation in Examples 301 to 318 and Comparative Example 301. The reflectance in the visible light range (380 nm to 780 nm) of the test piece was measured at 25 °C using an ultraviolet-visible spectrophotometer V-570 (manufactured by JASCO Corporation).

[0310] ◎: The reflectance in the visible light range is 80% or more.

[0311] ○: The reflectance in the visible light range is 60% or more and less than 80%.

[0312] ×: The reflectance in the visible light range is less than 60%.

[0313] <Sealability>

[0314] A test substrate imitating the unevenness of the substrate with a semiconductor element shown in Figure 3 was prepared (a plate with a width of 200 μm for the concave part, a height of 5 μm for the convex part, and a width of 200 μm for the convex part formed on one side of a glass plate with a size of 25 mm × 25 mm).

[0315] The dry film of each example / comparative example was cut into a size of 30 mm × 30 mm. For the dry film with a protective film, the protective film was peeled off, and in the state with a release liner, the exposed dry film surface was placed on the uneven part of the glass substrate. Then, TPX with a thickness of 50 μm (Opulent X-44B, manufactured by Mitsui Chemicals Tohcello, Inc.) as a buffer material and a vinyl chloride film with a thickness of 2.0 mm (Celeb T, manufactured by Okamoto Corporation) were sequentially laminated on the release liner surface, and further, cardboard was laminated to prevent adhesion. Next, the substrate surface was pressed from above the test piece at 5 MPa and 100 °C for 20 minutes to fill the dry film into the unevenness of the substrate, thereby forming a sealing layer. After pressing, the release liner, buffer material, and cardboard were peeled off.

[0316] The sealing layer protruding from the substrate of the obtained test piece was removed to expose the side surface of the substrate, and a state where the uneven part could be observed was set. The sealability was evaluated by observing any 20 concave parts of the substrate using a laser microscope. The case where the sealing layer was closely adhered to the concave part of the substrate without gaps was regarded as the groove being filled. The evaluation criteria are as follows.

[0317] ◎: 18 or more grooves were filled.

[0318] ○: 17 or less and 15 or more grooves were filled.

[0319] △: 14 or less and 12 or more grooves were filled.

[0320] ×: The number of trenches filled is 11 or less.

[0321] <Low-temperature curability 1>

[0322] For the dry films of Examples 1 to 51 and Comparative Examples 1 to 4, a film with a thickness of 38 μm (SP-PET-O1, manufactured by Mitsui Chemicals Tohcello, Inc.) was attached as a protective film to the exposed dry film surface. Subsequently, it was heat-cured at 150 °C for 2 hours. Here, when a photoinitiator was contained, a UV irradiation device (a high-pressure mercury UV lamp manufactured by Eyegraphics Co., Ltd.) was used to irradiate ultraviolet rays at an output density of 120 W / cm and a cumulative light quantity of 500 mJ / cm 2 for curing.

[0323] For the cured dry film, the protective film and the release liner were peeled off, and a test piece with a width of 30 mm and a length of 100 mm was produced. The weight of the test piece was measured, and it was attached to a 300-mesh stainless steel wire mesh. To prevent the test piece from falling off, the wire mesh was folded, and it was immersed in methyl ethyl ketone as an extraction liquid in a state where the test piece was wrapped, and left standing at 40 °C for 24 hours. After immersion, the wire mesh was taken out, washed with a small amount of methyl ethyl ketone, dried at 100 °C for 30 minutes, and then the weight was measured. The gel fraction was calculated by the following formula.

[0324] (Gel fraction) = {(W2 - W0) / (W1 - W0)} × 100

[0325] W0: The weight of the wire mesh

[0326] W1: The weight of the wire mesh + the test piece

[0327] W2: The weight of the wire mesh + the test piece after drying

[0328] The evaluation criteria are as follows.

[0329] ○: The gel fraction is 70% or more

[0330] △: The gel fraction is 40% or more and less than 70%

[0331] ×: The gel fraction is less than 40%

[0332] <Low-temperature curability 2>

[0333] Prepare a dry film obtained by cutting dry films with a release liner and a protective film of Examples 101 to 116, Examples 201 to 218, Examples 301 to 318, Examples 401 to 418, Comparative Example 101, Comparative Example 201, Comparative Example 301, and Comparative Example 401 into 100 mm × 100 mm. Then, prepare a dry film obtained by cutting a dry film with a release liner and a protective film into 100 mm × 100 mm, peel off the protective film, and place the dry film surface in the state with the release liner on a glass plate (120 mm × 120 mm × 1.1 mm, blue plate glass, manufactured by Kawamura Kuzo Shoten Co., Ltd.). At this time, mark the glass to know the longitudinal (Machine Direction, MD) direction of the release liner. After that, sequentially stack a 50-μm-thick TPX (Opulent X-44B, manufactured by Mitsui Chemicals Tohcello Co., Ltd.) as a buffer material and a 2.0-mm-thick vinyl chloride film (Celeb T, manufactured by Okamoto Co., Ltd.) on the release liner surface. Furthermore, stack cardboard to prevent adhesion.

[0334] Next, press the substrate surface from above the test piece under the conditions of 5 MPa and 100 °C for 20 minutes to form a precursor of the sealing layer on the glass plate. After pressing, peel off the cardboard and the buffer material. After that, leave the precursor in the state with the release liner at 130 °C, 140 °C, or 150 °C for 120 minutes respectively to harden the dry film at each temperature and obtain a hardened product in the state with the release liner. In addition, the MD direction means Machine Direction and refers to the flow direction (long side direction) of the sheet, and the TD direction described later means the transverse direction (Transverse Direction) and refers to the direction orthogonal to the flow direction.

[0335] For the hardened product in the state with the release liner (the hardened product hardened at three temperatures), evaluate the shrinkage resistance characteristics of the upper surface side of the hardened product and the adhesion of the hardened product to the glass plate according to the method described later, and comprehensively evaluate the low-temperature hardenability according to the following criteria.

[0336] ◎: Among the six evaluation results, the number of △ evaluations is one or less and the number of × evaluations is 0.

[0337] ○: Among the six evaluation results, the number of △ evaluations is two or less and the number of × evaluations is 0.

[0338] △: Among the six evaluation results, the number of △ evaluations is three or less and the number of × evaluations is 0.

[0339] ×: Among the six evaluation results, the number of × evaluations is one or more.

[0340] [Shrinkage property on the upper surface side of the cured product]

[0341] To observe the cross-section of the dry film cured product, the cured product in the state with the release liner was cut into two parallel to the MD direction at a position 30 mm from one end of the release liner in the TD direction. A laser microscope was used to observe the cross-section.

[0342] As Figure 4 shown, the position of the end on the lower surface side of the cured product 11' (i.e., the end of the cured product 11' in contact with the glass plate 31) was set as H1, the position of the end on the upper surface side of the cured product 11' (i.e., the contact point between the lower surface side of the release liner 12 and the cured product 11') was set as H2, and the distance L (μm) between the intersection point with the glass surface when drawing a perpendicular line from H2 toward the glass plate 31 and H1 was obtained, and the shrinkage property on the upper surface side of the cured product 11' was evaluated according to the following criteria.

[0343] ◎: The value of L is less than 320 μm.

[0344] ○: The value of L is 320 μm or more and less than 400 μm.

[0345] △: The value of L is 400 μm or more and less than 800 μm.

[0346] ×: The value of L is 800 μm or more.

[0347] [Adhesion]

[0348] The release liner was peeled off from the cured product of the dry film in the state with the release liner. According to JIS K 5600-5-6 (cross-cut method), a right-angled grid pattern (25 grids) with a side length of 1 mm was made on the laminated cured product using a cross-cut guide and a cutter. Then, an adhesive tape (CT1835, manufactured by Nichiban Co., Ltd.) was attached to the portion obtained by cutting the grid and closely adhered to the cured product. It was peeled off at an angle close to 60° within 5 minutes after attachment for 0.5 seconds to 1.0 second. Then, the adhesion was evaluated according to the following criteria. In addition, when the cured product of the dry film was peeled off from the glass plate at the stage of peeling off the protective film, it was rated as ×.

[0349] ○: The number of peeled-off grids is 0.

[0350] △: The number of peeled-off grids is 1 to 5.

[0351] ×: The number of peeled-off grids is 6 to 25.

[0352] <Storage stability of the dry film>

[0353] The dry films of each example / comparative example were subjected to a heating acceleration test at 40°C for 1 hour, and the sealing performance was evaluated in the same manner as the dry film before the heating acceleration test. The evaluation criteria are as follows.

[0354] ◎: The number of filled grooves is 17 or more.

[0355] ○: The number of filled grooves is 16 or less and 14 or more.

[0356] △: The number of filled grooves is 13 or less and 12 or more.

[0357] ×: The number of filled grooves is 11 or less.

[0358] <Operability of dry film>

[0359] The protective film of the dry film of each example / comparative example was peeled off, and the surface of the exposed dry film was evaluated for stickiness by touching it with a finger.

[0360] ○: No stickiness.

[0361] △: Slightly sticky.

[0362] ×: Sticky.

[0363] <Evaluation of the appearance of the cured product (change in transparency)>

[0364] For the dry films with a release liner and a protective film of Examples 101 to 116, Comparative Example 101, Examples 201 to 218, and Comparative Example 201, a buffer material and cardboard were used in the same manner as in the transparency test. The dry film with the release liner was pressed onto a glass plate at 5 MPa and 100°C for 20 minutes to make it adhere.

[0365] After pressing, the buffer material and cardboard were peeled off, and the sample was left standing in an oven at 130°C for 2 hours in the laminated state of [release liner / dry film / glass plate].

[0366] Subsequently, the release liner was peeled off, and for each glass plate, the haze value of the cured product of the dry film was measured.

[0367] The change in the haze value before and after heating in the oven at 130°C for 2 hours was calculated and evaluated according to the following criteria.

[0368] ○: The change in haze is less than 20%.

[0369] △: The change in haze is 20% or more and less than 50%.

[0370] ×: The change in haze is 50% or more.

[0371] In addition, for the dry films with a release liner and a protective film in Examples 301 to 318, Examples 401 to 418, Comparative Example 301, and Comparative Example 401, since the transparency cannot be measured, this evaluation is not performed.

[0372] [Table 2]

[0373]

[0374]

[0375] [Table 4A] Table 4A

[0376]

[0377] [Table 4B] Table 4B

[0378]

[0379] [Table 5A] Table 5A

[0380]

[0381] [Table 5B] Table 5B

[0382]

[0383] [Table 6A] Table 6A

[0384]

[0385] [Table 6B] Table 6B

[0386]

[0387] [Table 7A] Table 7A

[0388]

[0389] [Table 7B] Table 7B

[0390]

Claims

1. A thermal free radical polymerizable dry film, which is a dry film for filling the gaps between a plurality of micro light emitting diodes formed on a substrate and curing the gaps, and The thermal free radical polymerizable dry film contains a free radical polymerizable organic compound and a thermal free radical polymerization initiator. The 10-hour half-life temperature of the thermal radical polymerization initiator is 60° C. or higher and 170° C. or lower. The radical polymerizable organic compound includes at least one of the following: (i) a free radical polymerizable polymer (a); (ii) a free radical polymerizable oligomer (b) which is liquid at room temperature and pressure; and (iii) a radical polymerizable monomer (c) which is liquid at room temperature and pressure, The glass transition temperature of the radical polymerizable polymer (a) is -50°C or higher and 90°C or lower, The loss tangent tanδ80 at 80°C obtained by dynamic viscoelasticity measurement is 0.3 to 0.

7.

2. The thermal free radical polymerizable dry film according to claim 1, wherein: The storage elastic modulus G'80 at 80°C obtained by dynamic viscoelasticity measurement is 5×10 4 Pa~5×10 7 Pa.

3. The thermal radical polymerizable dry film according to claim 1 or 2, wherein: The dynamic friction coefficient of the surface of the thermal radical polymerizable dry film is 0.5 or less.

4. The thermal radical polymerizable dry film according to claim 1 or 2, wherein: The colorant is contained in an amount of 0.1 to 80% by mass based on 100% by mass of the total solid content. 5 . The thermal radical polymerizable dry film according to claim 1 , which has a thickness of 0.5 μm to 100 μm.

6. The thermal radical polymerizable dry film according to claim 1 or 2, wherein: The 10-hour half-life temperature of the thermal radical polymerization initiator is 100° C. or higher and 170° C. or lower, and the amount of the thermal radical polymerization initiator blended is 0.01% by mass to 20% by mass in the total solid content.

7. The thermal radical polymerizable dry film according to claim 1 or 2, comprising a peroxide-based thermal radical polymerization initiator as the thermal radical polymerization initiator. The 10-hour half-life temperature of the peroxide-based thermal radical polymerization initiator is 60° C. or higher and 120° C. or lower. In 100% by mass of the radically polymerizable organic compound, 95% by mass or more of a radically polymerizable polymer (a) having a glass transition temperature of -50°C to 90°C is contained, The radically polymerizable polymer (a) contains a radically polymerizable acrylic polymer.

8. The thermal radical polymerizable dry film according to claim 7, wherein: The peroxide-based thermal radical polymerization initiator has a 10-hour half-life temperature of 80° C. or higher and 110° C. or lower.

9. The thermal free radical polymerizable dry film according to claim 7, wherein: The amount of the peroxide-based thermal radical polymerization initiator blended is 0.01% by mass to 20% by mass based on the total solid content.

10. An electronic device comprising the cured product of the thermal radical polymerizable dry film according to any one of claims 1 to 9.

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