Dry film, cured product, and electronic component

Abstract

To provide dry films with excellent optical properties, semiconductor device encapsulation, low temperature curability, storage stability, and handling properties.SOLUTION: It is a dry film containing a radical polymerizable organic compound and a thermal radical polymerization initiator, and the thermal radical polymerization initiator can be solved by dry films in which the thermal radical polymerization initiator has a 10-hour half-life temperature equal to or more than 60°C and equal to or less than 170°C.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a dry film and an electronic device including a cured product thereof.

Background Art

[0002] Dry films are used as encapsulants for semiconductor elements. In particular, there is a need for dry films with excellent processability and optical suitability as materials disposed around partition walls in optical sensor modules and around each light-emitting element of RGB in displays using LEDs. For example, Patent Document 1 discloses a dry film composed of a photoinitiator. Conventionally, as a method for encapsulating LEDs, a method is known in which a dry film is embedded in a region where a plurality of LEDs are arranged by heat pressing or the like, and the dry film is cured by ultraviolet irradiation. Also, Patent Document 2 discloses a light-shielding dry film composed of a polymer resin having a specific glass transition temperature and weight average molecular weight, an epoxy-based material, and carbon black.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, micro LEDs, which have been actively developed, have a narrow interval of 10 to 250 μm between LEDs, and it is necessary to encapsulate these minute grooves without any gaps. However, conventional dry films do not sufficiently fill the spaces between the grooves, resulting in the generation of voids (also referred to as sealing properties). After sealing, the cured dry film was required to maintain high transparency for a long time so as not to impair the brightness of the micro-LED element. On the other hand, in applications for suppressing color mixing of adjacent light-emitting elements, excellent optical properties such as high light-shielding properties were required. Also, from the viewpoints of reducing thermal damage to components and shortening the sealing process time, a dry film that cures quickly at low temperatures (also referred to as low-temperature curability) has been demanded. In addition, there has been a problem that the curing reaction progresses after a long period of time and the sealing performance deteriorates, and it has been required to maintain stable sealing performance even after long-term storage (also referred to as storage stability). Furthermore, a dry film that is easy to handle during work without surface tack (also referred to as handleability) has been demanded. Therefore, an object of the present invention is to provide a dry film excellent in optical properties, sealing properties, low-temperature curability, storage stability, and handleability.

Means for Solving the Problems

[0005] As a result of intensive studies to solve the above problems, the present inventors have found that a dry film containing a radically polymerizable organic compound and a thermal radical polymerization initiator, wherein the 10-hour half-life temperature of the thermal radical polymerization initiator of the dry film is 60°C or higher and 170°C or lower, results in a dry film excellent in optical properties, sealing properties, low-temperature curability, storage stability, and handleability, and thus have reached the present invention.

[0006] That is, the present invention provides the dry films, cured products, and electronic components described in the following [1] to [8]. [1]: A dry film containing a radically polymerizable organic compound and a thermal radical polymerization initiator, wherein the 10-hour half-life temperature of the thermal radical polymerization initiator is 60°C or higher and 170°C or lower. [2]: The dry film according to [1], wherein the radically polymerizable organic compound contains a radically polymerizable polymer (a) having a glass transition temperature of -50°C or higher and 90°C or lower. [3]: The dry film according to [1], comprising at least one of a radically polymerizable oligomer (b) and a radically polymerizable monomer (c) that is liquid at normal temperature and pressure. [4]: The storage modulus (G’80) at 80 °C obtained by dynamic viscoelasticity measurement is 5×10 4 Pa to 5×10 7 Pa, and the dry film according to [2] or [3] is characterized by this. [5]: The loss tangent (tanδ80) at 80 °C obtained by dynamic viscoelasticity measurement is 0.3 to 0.7, and the dry film according to [4] is characterized by this. [6]: The dry film according to [5], wherein the coefficient of dynamic friction on the surface of the dry film is 0.5 or less. [7]: The dry film according to [6], containing 0.1 to 80% by mass of a colorant in 100% by mass of the total solid content of the dry film. [8]: An electronic device comprising a cured product of the dry film according to [7].

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a dry film, a cured product, and an electronic component that are excellent in optical properties, sealing properties, low-temperature curability, storage stability, and handleability.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0009] Hereinafter, the dry film of the present invention will be described more specifically. Note that the embodiments described below illustrate an example of the present invention. The present invention is not limited to the following embodiments, and also includes modifications implemented within the scope without changing the gist of the present invention. In this specification, a numerical range specified using "~" shall include the numerical values described before and after "~" as the range of the lower limit value and the upper limit value. (Meth)acrylic acid refers to acrylic acid and methacrylic acid. Also, unless otherwise noted, each of the various components appearing in this specification may be used alone or in combination of two or more. When using two or more in combination, the content rate uses the total value. Figure 1 is a schematic cross-sectional view of the dry film 11 of an embodiment of the present invention. The dry film 11 shown in Figure 1(i) has a two-layer structure in which a release liner 12 is laminated on the dry film 11. As shown in (ii), a protective film 13 may be formed on the surface of the dry film 11 opposite to the surface on which the release liner 12 is laminated. The dry film 11 may be provided with other layers between the dry film and the release liner 12 or the protective film 13 as needed.

[0010] The dry film of the present invention is preferably used for encapsulating semiconductor elements. In particular, a form used as a fixing agent for a plurality of optical semiconductor elements used as a light source for a display is preferable. The fixing agent may be used as a highly transparent fixing agent that does not impair the luminance of the semiconductor element, or may also be used as a light-shielding layer (also referred to as a partition wall) that prevents color mixing of light. Displays using a plurality of optical semiconductor elements as a light source include, for example, displays that require high quality, such as organic EL display panels, liquid crystal display panels, micro LED display panels, plasma display panels, and electronic paper.

[0011] The dry film is preferably laminated by being directly adhered to the adherend. Examples of the adherend include, in addition to the plurality of optical semiconductor elements (micro LEDs) described above, those having a substrate electrode portion made of metal, and those having a plurality of optical semiconductor element portions such as a backlight module and an organic EL. Further, it may have a substrate such as acrylic, polycarbonate, epoxy, polyimide, glass, glass epoxy, ITO, or polyethylene terephthalate. Since the dry film has high followability with respect to the uneven surface, a usage method in which the dry film follows a plurality of optical semiconductor elements and fills the space between the optical semiconductor elements is suitable. By filling the dry film between the optical semiconductor elements and curing it, the cured product of the dry film functions as a fixing agent for fixing the adjacent optical semiconductor elements on the substrate. When the dry film contains a colorant, the cured product of the dry film filled and cured between the optical semiconductor elements functions as a partition wall that shields the light sources of the adjacent optical semiconductor elements and prevents color mixing of light. In particular, since the dry film can follow micro-sized optical semiconductor elements, micro LEDs are more suitable as the optical semiconductor elements. When the dry film contains a colorant, it is more preferable to use the dry film as a partition wall of the micro LED display panel. Hereinafter, an example of the step of forming the fixing agent or the partition wall will be described with reference to FIG. 2.

[0012] Step (a): Placement step of the dry film As shown in an example in FIG. 2(a), the dry film 11 is placed on a substrate having a plurality of optical semiconductor elements. The placement preferably directly covers the optical semiconductor elements. If it has a release liner, it may be peeled off immediately after placement, or may be peeled off after the pressing step described below. In this specification, the plurality of optical semiconductor elements are not particularly limited as long as they are two or more optical semiconductor elements. Also, the emission color of the optical semiconductor elements is not particularly limited, and organic EL emission elements and LED optical semiconductor elements can be applied. Examples of the emission color include red, green, and blue. The size of the optical semiconductor element is such that the thickness is 100 μm or less and the area in plan view is 40,000 μm 2The following are preferred, with a thickness of 50 μm or less and an area in plan view of 10,000 μm 2 The following are more preferred, with a thickness of 20 μm or less and an area in plan view of 2,500 μm 2 The following are even more preferred. The distance between the optical semiconductor elements placed on the substrate is, for example, 10 to 5,000 μm. When red, green, and blue optical semiconductor elements are set as one pixel and placed on the substrate, the distance between the pixels is, for example, 10 to 2,000 μm, preferably 20 to 1,800 μm, and more preferably 500 to 1,500 μm. The distance between the optical semiconductor elements in one pixel is, for example, 10 to 250 μm, preferably 10 to 100 μm, and more preferably 20 to 60 μm.

[0013] Step (b): Pressing step As shown in Fig. 2(b), the dry film 11 is made to flow by pressing and filled between a plurality of optical semiconductor elements. The dry film 11 filled between the plurality of optical semiconductor elements serves as a fixing agent or a partition wall. The pressing method is not particularly limited, but 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 to 200 °C, more preferably 50 to 150 °C, even more preferably 60 to 130 °C, and most preferably 80 to 120 °C.

[0014] In order to enhance the adhesion to the optical semiconductor element and the adherend, after pressing, heat aging may be further performed. The heating temperature is preferably 80 to 250 °C, more preferably 100 to 220 °C, and even more preferably 140 to 190 °C. The heating time is preferably 30 to 300 minutes, more preferably 60 to 240 minutes, and even more preferably 90 to 180 minutes. By setting the above heating temperature and heating time, the residual stress of the dry film can be removed, the adhesion surface can be smoothed, and the thermosetting of the dry film forming the fixing agent or the partition wall can be promoted. After undergoing the above pressing step and heat aging step, the dry film is thermoset and becomes a cured product (also referred to as a cured material) of the dry film. By curing, the toughness, durability of the fixing agent or the partition wall are improved, and the adhesion to the adherend is also increased. Heat aging may be performed after step (c) described below.

[0015] Step (c): Etching step In step (c), etching is performed to remove or thin the cured product of the dry film on the optical semiconductor element. By removing the cured product of the dry film, the luminance of the light-emitting element is increased and the visibility during light emission is ensured. The thickness of the fixing agent or the partition wall after etching is preferably about the same as the thickness of the optical semiconductor element as shown in Fig. 2(c-1) or below the thickness of the dry film as shown in Fig. 2(c-2). Note that even if the dry film is not completely removed from the light-emitting element, it is sufficient if it can be substantially removed, and a state where some thin film remains may be acceptable. Also, if the luminance of the light-emitting element is sufficiently ensured, the etching step may not be performed. The etching method is not particularly limited, but wet etching methods such as chemical polishing using a chemical agent, physical polishing using an abrasive, laser etching, plasma etching using argon plasma or oxygen plasma, and dry etching methods such as ion beam etching are preferable examples. From the viewpoint of reducing surface irregularities, it is preferable to use a combination of a wet etching method and a dry etching method. Also, physical etching such as plasma treatment may be used. As the etching conditions, for example, dry etching may be performed using a mixed gas of CF4 / O2 / N2 in an anisotropic plasma apparatus under the conditions of an output of 1500 to 3000 W and 180 to 600 seconds. At this time, the gas supply amount of CF4 may be, for example, 50 to 100 sccm, the gas supply amount of O2 may be, for example, 500 to 1000 sccm, and the gas supply amount of N2 may be, for example, 50 to 100 sccm.

[0016] <Dry film> The dry film contains a radically polymerizable organic compound and a thermal radical polymerization initiator. The thickness of the dry film is preferably, for example, 0.5 to 100 μm, more preferably 1 to 50 μm. By being within this range, the dry film will have excellent sealing properties. 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 examples below. When the dry film contains a colorant, the optical density of the dry film is preferably 3 or more. If the optical density is 3 or more, sufficient light shielding properties can be maintained. The optical density can be adjusted according to the type and content of the colorant. Also, the optical density can be measured by the method described in the examples below. When the dry film contains a colorant, in a so-called mainly photo-polymerized dry film, the higher the light shielding property, the more difficult it is for light to reach the inside of the dry film, and an uncured portion is likely to occur. However, in the dry film of the present application, since polymerization proceeds by heat, the internal curing proceeds uniformly, and an uncured portion inside the dry film is less likely to remain. Therefore, it is possible to cure uniformly while ensuring a higher light shielding property. When the dry film does not contain a colorant, in a so-called mainly photo-polymerized dry film, transparency is likely to decrease mainly due to yellowing caused by the remaining photo-radical polymerization initiator. However, in the dry film of the present application, since a thermal radical polymerization initiator is used, it is less likely to yellow. Therefore, it is possible to cure while ensuring higher transparency. Also, in a so-called mainly thermally crosslinked dry film, gas is generated when a crosslinking agent such as isocyanate reacts, and transparency is likely to decrease mainly due to the remaining foaming inside the dry film. However, in the dry film of the present application, since a thermal radical polymerization initiator is used, gas is less likely to be generated, and higher transparency can be ensured. Note that transparency can be measured by the method described in the examples below.

[0017] The storage modulus (G’80) at 80 °C obtained by measuring the dynamic viscoelasticity of the dry film is 4 5×10 7 Pa to 5×10 4 Pa is preferable, and 10×10 7 Pa to 1×10 4Pa~5×10 6 It is more preferable that it is Pa. By setting G’80 to 5×10 4 Pa or more, the pressure applied to the dry film in the press process for sealing the semiconductor element is likely to be uniformly diffused. By setting G’80 to 5×10 7 Pa or less, it becomes easy to closely adhere following the semiconductor element, and the sealing property of the 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 examples below. By adjusting G’80 within the above range, the dry film can exhibit excellent fluidity in the press process.

[0018] Note that G’80 of the present invention can be adjusted by the type, composition and content of the radically polymerizable organic compound, and the content of the thermal radical polymerization initiator. When containing the radically polymerizable polymer (a) as the radically polymerizable organic compound, G’80 can be lowered by increasing the content of those having a low weight average molecular weight and / or a low glass transition temperature. When it is desired to increase G’80, the adjustment may be made conversely. When containing the radically polymerizable oligomer (b) and / or the radically polymerizable monomer (c) as the radically polymerizable organic compound, G’80 can be lowered by increasing the content of those having a low viscosity. When it is desired to increase G’80, the adjustment may be made conversely. Further, G’80 can be increased by increasing the content of the thermal radical polymerization initiator. When it is desired to lower G’80, the adjustment may be made conversely.

[0019] The loss tangent (tanδ80) at 80°C obtained by measuring the dynamic viscoelasticity of the dry film is preferably 0.3 to 0.7, and more preferably 0.4 to 0.6. By setting tanδ80 to 0.3 or more, the pressure applied to the dry film in the press process for sealing the semiconductor element is likely to be uniformly diffused. By setting tanδ80 to 0.7 or less, it becomes easy to closely adhere following the semiconductor element, and the sealing property of the semiconductor element becomes excellent. tanδ80 can be measured by the same method as G’80. By adjusting tanδ80 within the above range, the diffusibility of the pressure of the dry film in the pressing process can be enhanced. tanδ80 can be adjusted according to the type, composition and content of the radically polymerizable organic compound, and the content of the thermal radical polymerization initiator. When containing the radically polymerizable polymer (a) as the radically polymerizable organic compound, tanδ80 can be lowered by increasing the content of those with a low weight average molecular weight and / or a low glass transition temperature, and when it is desired to increase tanδ80, the opposite adjustment can be made. When containing the radically polymerizable oligomer (b) and / or the radically polymerizable monomer (c) as the radically polymerizable organic compound, tanδ80 can be lowered by increasing the content of those with a low viscosity, and when it is desired to increase tanδ80, the opposite adjustment can be made. Further, tanδ80 can be increased by increasing the content of the thermal radical polymerization initiator, and when it is desired to lower tanδ80, the opposite adjustment can be made.

[0020] The coefficient of kinetic friction on the surface of the dry film is preferably 0.5 or less, more preferably 0.4 or less, and even more preferably 0.35 or less. By setting the coefficient of kinetic friction to 0.5 or less, the flow of the dry film at the contact surface between the semiconductor element and the dry film in the pressing process for sealing the semiconductor element becomes good, and the sealing property of the semiconductor element becomes excellent. Also, when adhering the adherend such as the semiconductor element to the dry film, air bubbles are less likely to enter, and the transparency becomes excellent. Incidentally, the lower limit of the coefficient of kinetic friction is 0 or more, and the closer it is to 0, the more preferable. The coefficient of kinetic friction can be measured, for example, by the method described in the examples below. The coefficient of kinetic friction can be adjusted by the type, composition, and content of the radically polymerizable organic compound, and the content of the thermal radical polymerization initiator. When containing a radically polymerizable polymer (a) as the radically polymerizable organic compound, the coefficient of kinetic friction can be lowered by increasing the content of those having a high glass transition temperature, and when it is desired to increase the coefficient of kinetic friction, the opposite adjustment may be made. When containing a radically polymerizable oligomer (b) and / or a radically polymerizable monomer (c) as the radically polymerizable organic compound, the coefficient of kinetic friction can be lowered by increasing the content of those having a low viscosity, and when it is desired to increase the coefficient of kinetic friction, the opposite adjustment may be made. Further, the coefficient of kinetic friction can be lowered by increasing the content of the thermal radical polymerization initiator, and when it is desired to increase the coefficient of kinetic friction, the opposite adjustment may be made.

[0021] <Radically polymerizable organic compound> The radically polymerizable organic compound is an organic compound containing a radically polymerizable group that polymerizes and / or crosslinks to increase the molecular weight by applying activation energy in the presence of a thermal radical polymerization initiator. The radically polymerizable organic compound adjusts the shrinkage force during thermosetting, and suitable sealing properties and low-temperature curability are achieved. 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 preferably has at least one or more radically polymerizable groups in one molecule, more preferably two or more, and even more preferably a (polyfunctional) compound having three or more. This facilitates the formation of a crosslinked structure of the molecule and improves the low-temperature curability.

[0022] Among the radically polymerizable organic compounds, compounds having a (meth)acryloyl group are preferable because they are easy to synthesize, obtain, and handle. They are also preferable from the viewpoint of transparency. For example, epoxy (meth)acrylate, urethane (meth)acrylate, polyester (meth)acrylate, polyether (meth)acrylate, and (meth)acrylic acid esters of alcohols can be mentioned.

[0023] Epoxy (meth)acrylate is an acrylate obtained by reacting, for example, a conventionally known aromatic epoxy resin, alicyclic epoxy resin, aliphatic epoxy resin, etc. with (meth)acrylic acid. Preferred urethane (meth)acrylates are (meth)acrylates obtained by reacting one or more hydroxyl group-containing polyesters or hydroxyl group-containing polyethers with a hydroxyl group-containing (meth)acrylic acid ester and isocyanates, and (meth)acrylates obtained by reacting a hydroxyl group-containing (meth)acrylic acid ester with isocyanates, etc.

[0024] Preferred hydroxyl group-containing polyesters are hydroxyl group-containing polyesters obtained by reacting one or more polyhydric alcohols with one or more polybasic acids. Examples of aliphatic polyhydric alcohols include 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. Examples of polybasic acids include adipic acid, terephthalic acid, phthalic anhydride, trimellitic acid, etc.

[0025] Preferred hydroxyl group-containing polyethers are hydroxyl group-containing polyethers obtained by adding one or more alkylene oxides to a polyhydric alcohol. Examples of polyhydric alcohols are the same as those described above. Examples of alkylene oxides include ethylene oxide, propylene oxide, and butylene oxide.

[0026] Preferred hydroxyl group-containing (meth)acrylic acid esters are hydroxyl group-containing (meth)acrylic acid esters obtained by an esterification reaction of a polyhydric alcohol and (meth)acrylic acid. Examples of polyhydric alcohols are the same as those described above.

[0027] Among such hydroxyl group-containing (meth)acrylic acids, the hydroxyl group-containing (meth)acrylate obtained by the esterification reaction of a dihydric alcohol and (meth)acrylic acid is particularly preferred, and examples thereof include 2-hydroxyethyl (meth)acrylate.

[0028] As the isocyanates, compounds having at least one isocyanate group in the molecule are preferred, and divalent isocyanate compounds such as tolylene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate are particularly preferred.

[0029] Preferred polyester (meth)acrylates are those obtained by reacting a hydroxyl group-containing polyester with (meth)acrylic acid. Preferred hydroxyl group-containing polyesters used herein are hydroxyl group-containing polyesters obtained by the esterification reaction of one or more polyhydric alcohols with one or more monobasic acids and polybasic acids. Examples of the polyhydric alcohols include the same compounds as those described above. Examples of the monobasic acids include formic acid, acetic acid, butyric acid, and benzoic acid. Examples of the polybasic acids include adipic acid, terephthalic acid, phthalic anhydride, and trimellitic acid.

[0030] Preferred polyether (meth)acrylates are those obtained by reacting a hydroxyl group-containing polyether with (meth)acrylic acid. Preferred hydroxyl group-containing polyethers used herein are hydroxyl group-containing polyethers obtained by adding one or more alkylene oxides to a polyhydric alcohol. Examples of the polyhydric alcohols include the same compounds as those described above. Examples of the alkylene oxides include ethylene oxide, propylene oxide, and butylene oxide.

[0031] Preferred (meth)acrylic acid esters of alcohols are (meth)acrylates obtained by reacting an aromatic or aliphatic alcohol having at least one hydroxyl group in the molecule and an alkylene oxide adduct thereof with (meth)acrylic acid. Examples thereof include 2-ethylhexyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, isoamyl (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.

[0032] The radically polymerizable organic compound preferably contains a radically polymerizable polymer (a). Alternatively, it preferably contains at least one of a radically polymerizable oligomer (b) and a radically polymerizable monomer (c).

[0033] <Radically polymerizable polymer (a)> The radically polymerizable polymer (a) (hereinafter also referred to as polymer (a)) is an organic compound containing the above-described radically polymerizable group, and represents a high molecular compound having a weight average molecular weight of 10,000 or more and 1,000,000 or less.

[0034] The glass transition temperature of the radically polymerizable organic compound is preferably -50°C or higher and 90°C or lower, more preferably -15°C or higher and 65°C or lower, and most preferably 0°C or higher and 50°C or lower. By being within this range, a dry film with good sealing properties can be obtained. The glass transition temperature was measured by the method described in the examples below.

[0035] The content of the radically polymerizable organic compound is preferably 10 to 98% by mass, more preferably 40 to 95% by mass, and even more preferably 60 to 90% by mass in 100% by mass of the total solid content of the dry film. By setting the content within the above range, the sealing properties and low-temperature curability can be suitably adjusted.

[0036] <Radically polymerizable oligomer (b)> The radically polymerizable oligomer (b) (hereinafter also referred to as oligomer (b)) is a polymer having a structural unit based on 2 to 100 monomers containing a radically polymerizable group and is liquid under normal temperature and pressure. It is also a compound having a weight average molecular weight of 100 or more and less than 10,000. The weight average molecular weight is more preferably 300 or more and 8,000 or less, even more preferably 400 or more and 6,000 or less, and most preferably 500 or more and 4,500 or less. By setting the weight average molecular weight within the above range, the fluidity of the dry film can be increased and the sealing properties can be improved. In the present invention, the normal temperature is 25°C and the normal pressure is 1 atm.

[0037] The content of oligomer (b) is preferably 0.1 to 70% by mass, more preferably 1 to 50% by mass, even more preferably 10 to 50% by mass, and most preferably 30 to 50% by mass in 100% by mass of the total solid content of the dry film. By setting the content within the above range, the sealing properties, low-temperature curability, and handleability can be suitably adjusted.

[0038] <Radically polymerizable monomer (c)> The radical polymerizable monomer (c) (hereinafter also referred to as monomer (c)) means a compound having a radical polymerizable group as the minimum structural unit for constituting an oligomer or a polymer, and is liquid under normal temperature and pressure. The monomer may be a monofunctional monomer or a polyfunctional monomer. In particular, (meth)acrylate compounds can be preferably used because they are easy to handle. From the viewpoint of sealing properties, it is preferable to contain a 2- to 6-functional (meth)acrylate monomer, and more preferably to contain a 2- to 3-functional (meth)acrylate monomer.

[0039] The content of the monomer (c) is preferably 0.01 to 70% by mass, more preferably 0.1 to 50% by mass, still more preferably 1 to 30% by mass, and most preferably 1 to 10% by mass in 100% by mass of the total solid content of the dry film. By setting the content as described above, the sealing property and the low-temperature curability can be suitably adjusted.

[0040] The radical polymerizable organic compound preferably contains either the radical polymerizable oligomer (b) or the radical polymerizable monomer (c), and may contain both.

[0041] When the dry film contains the oligomer (b) or the monomer (c), from the viewpoint of the handleability of the dry film, it is preferable to contain the binder resin described later for the purpose of suppressing tack. The binder resin preferably contains 30% by mass or more, more preferably 50% by mass or more, based on 100% by mass of the oligomer (b) or the monomer (c). By being in this range, it is possible to achieve both sealing properties and low-temperature curability and to obtain a dry film with good handleability.

[0042] <Thermal 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, preferably 80°C or higher and 160°C or lower, and more preferably 100°C or higher and 150°C or lower. By setting the 10-hour half-life temperature of the thermal radical polymerization initiator to 60 °C or higher, the storage stability of the dry film can be maintained, and good sealing properties can be maintained even after long-term storage. In addition, rapid progress of polymerization (curing) due to heat pressing during sealing can be prevented, and good sealing properties can be exhibited. By setting it to 170 °C or lower, the thermosetting temperature of the dry film can be lowered, and the curing time can be shortened, so that the low-temperature curability can be improved.

[0043] The 10-hour half-life temperature is the temperature at which the initiator concentration of the thermal radical polymerization initiator decreases to half after 10 hours due to thermal decomposition. Specifically, a thermal radical polymerization initiator solution is prepared using a solvent inert to the radicals of the thermal radical polymerization initiator, and sealed in a glass tube subjected to nitrogen substitution. This is immersed in a constant temperature layer set at a predetermined temperature for 10 hours for thermal decomposition, and the amount of the remaining thermal radical polymerization initiator is measured. These series of operations can be carried out at several temperatures, and the 10-hour half-life temperature can be obtained from the straight line obtained by plotting.

[0044] As the thermal 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 is preferably used. The thermal radical polymerization initiator adjusts the shrinkage force during thermosetting, and suitable sealing properties and low-temperature curability are achieved.

[0045] Examples of the organic peroxide polymerization initiator having a 10-hour half-life temperature of 60 °C or higher and 170 °C or lower include dialkyl peroxides such as di-t-amyl peroxide, di-t-butyl peroxide, di-t-hexyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, α,α'-bis(t-butylperoxy-m-isopropyl)benzene, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne-3, and 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane; Peroxy esters such as t-amyl peroxyacetate, t-butyl peroxyacetate, t-amyl peroxybenzoate, t-butyl peroxybenzoate, t-hexyl peroxybenzoate, t-amyl peroxy-2-ethylhexanoate, t-butyl peroxy-2-ethylhexanoate, t-hexyl peroxy-2-ethylhexanoate, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxyisobutyrate, t-amyl peroxyisononanoate, t-butyl peroxyisononanoate, t-butyl peroxylaurate, n-butyl 4,4-di-(t-butylperoxy)valerate, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 2,5-dimethyl-2,5-di-2-ethylhexanoylperoxyhexane; Peroxy ketals such as 2,2-bis(t-butylperoxy)butane, 2,2-bis(4,4-di-t-butylperoxycyclohexyl)propane, 1,1-bis(t-amylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 1,1-bis(t-hexylperoxy)cyclohexane, butyl 4,4-bis(t-butylperoxy)pentanoate; Hydroperoxides such as t-amyl hydroperoxide, cumene hydroperoxide, p-menthane hydroperoxide, diisopropylbenzene hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide; Diacyl peroxides such as dibenzoyl peroxide, dinonanoyl peroxide, dilauroyl peroxide, succinic peroxide; Peroxy carbonates such as t-butyl peroxyisopropyl carbonate, t-amyl peroxyisopropyl carbonate, t-hexyl peroxyisopropyl carbonate, t-butyl peroxy-2-ethylhexyl carbonate, t-amyl peroxy-2-ethylhexyl carbonate and the like, but not limited thereto. From the viewpoint of storage stability, dialkyl peroxides are preferred, and di-t-butyl peroxide is more preferred.

[0046] As the azo thermal polymerization initiator having a 10-hour half-life temperature of 60 °C or higher and 170 °C or lower, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile) and other 2,2'-azobisbutyronitrile; 1,1'-azobis(cyclohexane-1-carbonitrile) and other 1,1'-azobis-1-alkanenitrile; 2,2'-azobis(N-butyl-2-methylpropionamide) and other 2,2'-azobispropionamide; In addition, others include dimethyl 1,1'-azobis(1-cyclohexanecarboxylate), dimethyl 2,2'-azobis(2-methylpropionate), dimethyl, 2,2'-azobisisobutyrate, 1,1'-azobis(acetoxy-1-phenylethane), 2,2'-azobis(2,4,4-trimethylpentane), 2,2'-azobis[2-(2-imidazolin-2-yl)propane] and the like. In addition, azo compounds having a carboxyl group or a hydroxyl group include, for example, 4,4'-azibis(4-cyanopentanoic acid), 2,2'-azobis(2-methyl-N-(2-hydroxyethyl)propionamide) and the like, but are not limited thereto. From the viewpoint of storage stability, 2,2'-azobispropionamide is preferred, and 2,2'-azobis(N-butyl-2-methylpropionamide) is more preferred.

[0047] The thermal 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, and most preferably 4.4 to 13% by mass in 100% by mass of the total solid content of the dry film. By setting it within the above range, transparency can be improved. In addition, by setting it at 0.01% by mass or more, the low-temperature curability and handleability can be excellent, and by setting it at 20% by mass or less, the storage stability can be excellent.

[0048] In addition, from the viewpoint of storage stability, it is preferable not to use the thermal radical polymerization initiator in combination with the photo radical polymerization initiator.

[0049] <Other components> The dry film of the present invention may contain other components as long as the object of the present invention is not impaired. For example, a colorant, a binder resin, an inorganic filler, a dispersant, etc. can be added.

[0050] <Colorant> The colorant is added when the cured product of the dry film is used as a light-shielding layer (partition wall). As the colorant, it is preferable to use a black colorant (pigment, dye, etc.). Specifically, 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. can be mentioned. Only one kind of black-based colorant may be used, or two or more kinds may be used. Further, a colorant that exhibits a color other than black may be combined and used as a colorant that functions as a black-based colorant.

[0051] Among the colorants, carbon black is particularly preferable from the viewpoints of dispersibility in the radically polymerizable organic compound and light-shielding property. As the carbon black, the carbon black generally used for applications of black colorants can be used. As the carbon black, one or more kinds of known carbon blacks such as channel black, furnace black, thermal black, lamp black, and acetylene black can be used. Further, resin-coated carbon black may be used. Furthermore, carbon nanofibers and carbon nanotubes may be used. When carbon black is blended into the dry film, carbon black powder may be added, or a carbon black dispersion may be added. The average particle diameter of the 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 even more preferably 10 nm or more and 100 nm or less, from the viewpoint of light shielding property. The average particle diameter is the arithmetic mean primary particle diameter determined by observing with an electron microscope. From the viewpoint of dispersibility, the carbon black preferably has a specific surface area of 50 to 400 m 2 / g, a volatile content of 0.1 to 10% by weight, and a pH value of 2 to 10, more preferably a pH of 3 to 8, and even more preferably a pH of 3 to 6.

[0052] The compounding amount of the colorant is preferably 0.1 to 80% by mass, more preferably 0.5 to 40% by mass, even more preferably 1 to 32% by mass, and most preferably 5 to 20% by mass in 100% by mass of the total solid content of the dry film. By setting the content as described above, a dry film having good light shielding property, sealing property, and handleability can be obtained.

[0053] <Binder resin> The binder resin does not contain the above-mentioned radically polymerizable group and is an organic polymer compound different from the radically polymerizable organic compound. In addition, the binder 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 binder resin more preferably has a glass transition temperature of -15°C or higher and 50°C or lower, even more preferably 0°C or higher and 25°C or lower, and more preferably has a weight average molecular weight of 25,000 or higher and 200,000 or lower, and even more preferably 30,000 or higher and 100,000 or lower.

[0054] As the binder resin, known and commonly used thermosetting resins and thermoplastic resins can be used. Specifically, for example, acrylic resins, maleic resins, polybutadiene resins, polyester resins, polyurethane resins, epoxy resins, oxetane resins, phenoxy resins, polyimide resins, polyamide resins, phenol resins, alkyd resins, amino resins, polylactic acid resins, oxazoline resins, benzoxazine resins, silicone resins, fluorine resins, butyral resins, styrene-maleic acid copolymers, chlorinated polyethylene, chlorinated polypropylene, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyester resin, vinyl resin, alkyd resin, polystyrene resin, polyamide resin, rubber resin, cyclized rubber resin, celluloses, polyethylene (HDPE, LDPE), polybutadiene, carbodiimide resin, cyclocarbonate compound, episulfide resin, and polyimide resin, etc. can be mentioned. In particular, acrylic resin, polyurethane resin, and epoxy resin are preferable, and acrylic resin is more preferable. By containing the binder resin, the stickiness of the dry film can be adjusted, and the handleability of the dry film can be improved.

[0055] Furthermore, when a thermosetting resin is included as the binder resin, it is preferable to contain a curing agent to promote the formation of a crosslinked structure. 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 silane coupling agents, epoxy 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 degree of crosslinking of the dry film can be adjusted, and the low-temperature curability can be improved.

[0056] <Inorganic filler> The dry film can also contain an inorganic filler. By blending an inorganic filler, it is possible to suppress the curing shrinkage of the resulting cured product and improve thermal properties such as crack resistance. As the inorganic filler, conventionally known inorganic fillers can be used and are not limited to specific ones. For example, silica such as barium sulfate, barium titanate, amorphous silica, crystalline silica, fused silica, spherical silica, talc, clay, nobelgu silica particles, boehmite, magnesium carbonate, calcium carbonate, titanium oxide, aluminum oxide, aluminum hydroxide, silicon nitride, aluminum nitride, calcium zirconate, and metal powders such as copper, tin, zinc, nickel, silver, palladium, aluminum, iron, cobalt, gold, and platinum can be mentioned. The inorganic filler is preferably spherical particles. Among them, silica is preferable, which can suppress the curing shrinkage of the cured product of the dry film and improve properties such as adhesion and hardness.

[0057] The inorganic filler may be surface-treated. As the surface treatment, surface treatment with a coupling agent or surface treatment without introducing an organic group such as alumina treatment may be performed. The surface treatment method of the inorganic filler is not particularly limited, and a known and commonly used method may be used. For example, the surface of the inorganic filler may be 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.

[0058] <Method for forming a dry film> The method for forming a dry film is not particularly limited. As a preferred example, there is a method of forming a dry film by applying a liquid dry film precursor obtained by adding an arbitrary solvent to the components constituting the dry film and drying the solvent. The addition of the solvent is aimed at adjusting the viscosity level suitable for coating. For coating, known coating machines and techniques such as comma coater, die coater, roll coater, lip coater, reverse coater, gravure coater, bar coater, curtain coater, dip coating, spin coating, silk screen, and casting can be used. The solvent contained in the dry film precursor can be removed by a drying process after coating. As a preferred embodiment, after applying a dry film precursor to a support such as a release liner or a substrate, the coating film is dried by heating using a hot air oven, an infrared heater, etc., so that a dry film can be formed on one surface of the support. Further, in order to increase the crosslink density of the dry film, for example, an aging treatment such as standing under specific temperature conditions or irradiation with UV or the like may be performed.

[0059] <Release liner> The release liner supports the dry film and is the film on which the dry film precursor is applied when forming the dry film. Examples of the release liner include films made of thermoplastic resins such as polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyimide films, polyamideimide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, and polystyrene films, and paper and the like can be used. Among these, a polyester film can be preferably used from the viewpoints of heat resistance, mechanical strength, handleability, etc. The thickness of the release liner is not particularly limited, but is generally appropriately selected in the range of 10 to 150 μm according to the application. A release treatment may be applied to the surface of the release liner on which the dry film precursor is provided.

[0060] <Protective film> The protective film is preferably provided on the surface of the dry film opposite to the release liner for the purpose of preventing dust and the like from adhering to the surface of the dry film and improving the handleability. As the protective film, for example, polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyimide films, polyamideimide films, polyethylene films, polytetrafluoroethylene films, polypropylene films, polystyrene films, and the like, and films made of thermoplastic resins such as paper can be used. Among these, polyester films can be preferably used from the viewpoints of heat resistance, mechanical strength, handleability, and the like. The thickness of the protective film is not particularly limited, but is generally appropriately selected according to the application in the range of 10 to 150 μm. The surface of the protective film in contact with the dry film may be subjected to an antistatic treatment, an adhesion treatment, a release treatment, or an uneven treatment. Further, in the peeling force (Tl) between the release liner and the dry film and the peeling force (Th) between the protective film and the dry film, it is preferable to satisfy the relationship of Tl < Th.

[0061] <Electronic device> The cured product of the dry film is preferably provided in electronic devices such as liquid crystal displays, touch panels, notebook PCs, mobile phones, smartphones, and tablet terminals.

Examples

[0062] Hereinafter, the present invention will be specifically described by showing examples and comparative examples of the present invention. However, it goes without saying that the present invention is not limited to these examples. In the following, "parts" and "%" are all based on mass unless otherwise specified.

[0063] <Glass transition temperature> The glass transition temperature was determined by JIS-K7121 (DSC method: heating rate 10 ° C. / min). As the measuring device, a differential scanning calorimeter (DSC2500: manufactured by TA Instruments) was used.

[0064] The materials used in the examples and comparative examples are shown below.

[0065] <Radical polymerizable organic compound> · Radical polymerizable polymer (a)-1: To 100 parts by mass of Acrylic A-814 (manufactured by DIC Corporation, acrylic polyol resin, hydroxyl value 17.5 mgKOH / g), 15 parts by mass of a solvent (ethyl acetate) was added and stirred, and then 15 parts by mass of Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resona) was added, and the mixture was stirred at 60 °C for 24 hours to obtain radical polymerizable polymer (a)-1. The glass transition temperature was 85 °C. · Radical polymerizable polymer (a)-2: To 100 parts by mass of Acrylic A-801P (manufactured by DIC Corporation, acrylic polyol resin, hydroxyl value 50 mgKOH / g), 15 parts by mass of a solvent (ethyl acetate) was added and stirred, and then 15 parts by mass of Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resona) was added, and the mixture was stirred at 60 °C for 24 hours to obtain radical polymerizable polymer (a)-2. The glass transition temperature was 50 °C. · Radical polymerizable polymer (a)-3: To 100 parts by mass of Acrylic 44-127 (manufactured by DIC Corporation, acrylic polyol resin, hydroxyl value 70 mgKOH / g), 15 parts by mass of a solvent (ethyl acetate) was added and stirred, and then 15 parts by mass of Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resona) was added, and the mixture was stirred at 60 °C for 24 hours to obtain radical polymerizable polymer (a)-3. The glass transition temperature was 35 °C. · Radical polymerizable polymer (a)-4: To 100 parts by mass of Acrylic A-811 (manufactured by DIC Corporation, acrylic polyol resin, hydroxyl value 34 mgKOH / g), 15 parts by mass of a solvent (ethyl acetate) was added and stirred, and then 15 parts by mass of Karenz AOI (2-acryloyloxyethyl isocyanate, manufactured by Resona) was added, and the mixture was stirred at 60 °C for 24 hours to obtain radical polymerizable polymer (a)-4. The glass transition temperature was 20 °C. · Radical polymerizable polymer (a)-5: To 100 parts by mass of Acrylic 49-394-IM (manufactured by DIC, acrylic polyol resin, hydroxyl value 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 Resonaac) was added, and the mixture was stirred at 60 °C for 24 hours to obtain radical polymerizable polymer (a)-5. The glass transition temperature was 15 °C. · Radical polymerizable polymer (a)-6: To 100 parts by mass of Acrylic A-817 (manufactured by DIC, acrylic polyol resin, styrene-acrylic copolymer hydroxyl value 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 Resonaac) was added, and the mixture was stirred at 60 °C for 24 hours to obtain radical polymerizable polymer (a)-6. The glass transition temperature was 95 °C. · Radical polymerizable oligomer (b)-1: Unidic 17-806 (manufactured by DIC), an ultraviolet urethane acrylate resin composed of isocyanuric acid triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, and isophorone diisocyanate polyurethane. Liquid under normal temperature and pressure. · Radical polymerizable monomer (c)-1: Light Acrylate DPE-6A (manufactured by Kyoeisha Chemical Co., Ltd.), dipentaerythritol hexaacrylate. Liquid under normal temperature and pressure.

[0066] <Thermal radical polymerization initiator> As the thermal radical polymerization initiator, thermal polymerization initiators (A) to (G) described in Table 1 were used. Also, as the photopolymerization initiator, photopolymerization initiator (H) was used.

[0067]

Table 1

[0068] <Colorant> · Carbon Black MA100 (manufactured by Mitsubishi Chemical Corporation) <Binder resin> · Acridic A-801P (manufactured by DIC Corporation, isocyanate-curable acrylic resin, hydroxyl value is 50 mg KOH / g), glass transition temperature: 50 °C

[0069] [Example 1] To 100 parts by mass of the solid content of the radically polymerizable polymer (a)-1 as the radically polymerizable organic compound, 20 parts by mass of carbon black MA100 (manufactured by Mitsubishi Chemical Corporation) as a colorant and 200 parts by mass of methyl isobutyl ketone as a solvent were mixed in a 0.45 L container and preliminarily dispersed with a disperser. Then, 1300 parts by mass of zirconia beads with a diameter of 1.0 mm were filled, and thorough dispersion was carried out for 1 hour using a shaker (Scan-dex SK450, manufactured by Fast & Fluid Management). The zirconia beads were removed to obtain a black dispersion. To the obtained black dispersion, 5 parts by mass of the thermal radical polymerization initiator (A): Vam-110 (manufactured by Fujifilm Wako Pure Chemical Corporation) and 38 parts by mass of a diluting solvent (a mixed solvent of methyl ethyl ketone and toluene) were sequentially added while stirring with a disperser, and stirred until it became sufficiently uniform to obtain a dry film precursor (1). The dry film precursor (1) was applied onto the release layer of a release liner with a thickness of 75 μm (SP-PET-O3, manufactured by Mitsui Chemicals Toagosei Co., Ltd.) so that the thickness after drying would be 25 μm, and heated and dried in a hot air oven at 80 °C to form a dry film, and a dry film having a release liner was obtained.

[0070] [Examples 2 to 18, 28 to 43, Comparative Examples 1 and 2] As shown in Tables 2 and 3, Examples 2 to 18, 28 to 43, Comparative Examples 1 and 2 were obtained in the same manner as in Example 1 except that the radically polymerizable organic compound, the radical polymerization initiator, and the colorant were changed to the composition ratios shown in Tables 2 and 3. The composition ratios in Tables 2 and 3 are described in terms of the ratio of the active ingredients excluding the solvent.

[0071] [Example 19] As a radically polymerizable organic compound, a radically polymerizable oligomer (b)-1: 100 parts by mass of solid content, as a colorant, carbon black MA100 (manufactured by Mitsubishi Chemical Corporation): 20 parts by mass, and as a solvent, methyl isobutyl ketone: 200 parts by mass were mixed in a 0.45 L container and preliminarily dispersed with a disper. After that, 1300 parts by mass of zirconia beads with a diameter of 1.0 mm were filled, and thorough dispersion was carried out for 1 hour using a shaker (ScanDex SK450: manufactured by Fast & Fluid Management). The zirconia beads were removed to obtain a black dispersion. To the obtained black dispersion, 5 parts by mass of a thermal radical polymerization initiator (A): Vam-110 (manufactured by Fujifilm Wako Pure Chemical Corporation) was stirred with a disper until it became thoroughly uniform to obtain a dry film precursor (19). The dry film precursor (19) was applied onto the release layer of a release liner with a thickness of 75 μm (SP-PET-O3, manufactured by Mitsui Chemicals Toagosei Co., Ltd.) so that the thickness after drying would be 25 μm, and heated and dried in a hot air oven at 80 °C to form a dry film, thereby obtaining a dry film having a release liner. [Examples 20 to 27, 44 to 51, Comparative Examples 3 and 4] As shown in Tables 2 and 3, Examples 20 to 27, 44 to 51, Comparative Examples 3 and 4 were obtained in the same manner as in Example 19, except that the composition ratios of the radically polymerizable organic compound, the radical polymerization initiator, the colorant, and the binder resin in Table 2 were changed. The binder resin was added after preparing the black dispersion after dispersion.

[0072] <Storage elastic modulus at 80 °C (G’80) and loss tangent (tanδ80)> The dry film with the release liner removed was prepared to have a thickness of 1 mm or more. Note that it may be coated to a thickness of 1 mm, or dry films with a thickness of less than 1 mm may be laminated any number of times and laminated as necessary to make the thickness 1 mm or more. The obtained dry film was measured for storage modulus G’ using a measuring probe of φ8 mm with a rheometer (DHR-2 manufactured by TA Instruments) 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. Also, the loss tangent at 80 °C (tanδ80) was calculated by dividing the value of the loss modulus G’’ at 80 °C measured simultaneously by G’80.

[0073] <Coefficient of kinetic friction> The dry film with the release liner removed and cut to a width of 40 mm was placed on a friction measuring machine (FRICTION TESTER TR-2 manufactured by Toyo Seiki Seisakusho), and the coefficient of kinetic friction was calculated according to the measuring method specified in JIS K7125. A total of 5 measurements were made, and the average value was calculated and taken as the coefficient of kinetic friction of the dry film.

[0074] <Evaluation items> For all evaluations, ◎: very good, 〇: good, △: practical, and evaluations that did not meet the target performance were marked as ×. <Optical density> The optical density of the obtained dry film was measured. The optical density was determined using an optical densitometer (361T desktop transmission densitometer: manufactured by X-RITE). The evaluation criteria were as follows. Note that this evaluation was only performed on the examples and comparative examples containing a colorant. ◎: Optical density is 3 or more 〇: Optical density is 1 or more and less than 3 ×: Optical density is less than 1

[0075] <Transparency> The dry film with the release liner removed was cut into a size of 2.5 cm × 10 cm, and a glass plate (blue plate glass, manufactured by Kawamura Kuzo Shoten Co., Ltd.) with a thickness of 1.1 mm was attached and crimped. For the obtained test piece, a light resistance test was conducted for 48 hours using a carbon arc clamp with an ultraviolet fade meter U48 (manufactured by Suga Test Instruments Co., Ltd.). Next, the haze value and total light transmittance of the dry film were measured for the test piece using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., NDH8000). Incidentally, this evaluation was performed only for the examples and comparative examples that do not contain a colorant. ◎: Haze is 1% or less and total light transmittance is 97% or more 〇: Haze is 1% or more or total light transmittance is 97% or less ×: Haze is 1% or more and total light transmittance is 97% or less

[0076] <Sealing property> A test substrate (a plate in which a concave portion with a width of 200 μm, a convex portion with a height of 5 μm, and a convex portion with a width of 200 μm were formed on one surface of a glass plate with a size of 25 mm × 25 mm), which mimics the unevenness of the substrate with a semiconductor element shown in FIG. 3, was prepared. The dry film was cut into a size of 30 mm × 30 mm, and the dry film surface exposed with the release liner attached was placed on the uneven portions of the glass substrate. Then, as a cushion material, a 50-μm-thick TPX (Opulran X-44B, manufactured by Mitsui Chemicals Toagosei Co., Ltd.) and a 2.0-mm-thick vinyl chloride film (Celeb T, manufactured by Okamoto & Co., Ltd.) were laminated in order on the release liner surface, and further, a cardboard was laminated to prevent sticking. Next, the substrate surface was pressed from above the test piece at 5 MPa and 100 °C for 20 minutes, and the dry film was filled into the unevenness of the substrate to form a dry film. After pressing, the carrier film, the cushion material, and the cardboard were peeled off. The dry film protruding from the substrate of the obtained test piece was removed, and the side surface of the substrate was exposed so that the uneven portions could be observed. The sealing property was evaluated by observing any 20 concave portions of the substrate with an electron microscope. The case where the dry film was in close contact with the concave portion of the substrate without a gap was regarded as the groove being filled. The evaluation criteria were as follows. ◎: 18 or more of the embedded grooves 〇: Embedded grooves are 17 or less and 15 or more △: Embedded grooves are 14 or less and 12 or more ×: Embedded grooves are 11 or less

[0077] <Low-temperature curability> For the obtained dry film, a film with a thickness of 38 μm (SP-PET-O1, manufactured by Mitsui Chemicals Toagosei Co., Ltd.) was laminated as a protective film on the exposed dry film surface. Then, it was heat-cured at 150 °C for 2 hours. Here, for those containing a photoinitiator, using a UV irradiation device (high-pressure mercury UV lamp manufactured by Eye Graphics Co., Ltd.), ultraviolet rays were irradiated and cured so that the output density was 120 W / cm and the integrated light quantity was 500 mJ / cm 2 The cured dry film was peeled off from the protective film and the release liner to prepare a test piece with a width of 30 mm and a length of 100 mm. The weight of the test piece was measured, pasted onto a 300-mesh stainless steel wire mesh, the wire mesh was folded so that the test piece did not fall off, and it was immersed in methyl ethyl ketone as an extraction solution 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. (Gel fraction) = {(W2 - W0) / (W1 - W0)} × 100 W0: Weight of the wire mesh W1: Weight of the wire mesh + test piece W2: Weight of the wire mesh + test piece after drying The evaluation criteria were as follows. 〇: Gel fraction is 70% or more △: Gel fraction is 40% or more and less than 70% ×: Gel fraction is less than 40%

[0078] <Storage stability of dry film> A heat-accelerated test was conducted on the obtained dry film, and the sealing property was evaluated in the same manner as the dry film before the heat-accelerated test. The evaluation criteria were as follows. ​◎: In the sealing property evaluation after heating promotion at 40°C for 1 hour, the number of embedded grooves is 17 or more 〇: In the sealing property evaluation after heating promotion at 40°C for 1 hour, the number of embedded grooves is 16 or less and 14 or more △: In the sealing property evaluation after heating promotion at 40°C for 1 hour, the number of embedded grooves is 13 or less and 12 or more ×: In the sealing property evaluation after heating promotion at 30°C for 1 hour, the number of embedded grooves is 11 or less

[0079] <Handling property of dry film> The presence or absence of stickiness on the surface of the obtained dry film was evaluated by finger touch. 〇: Those without stickiness △: Those with slight stickiness ×: Those with stickiness

[0080] The evaluation results are shown in Tables 2 and 3.

[0081]

Table 2

Table 3

[0082] As shown in Comparative Example 1, when the 10-hour half-life temperature was less than 60°C, the polymerization (curing) reaction proceeded rapidly during the heat press at the time of sealing or at the start of the heating acceleration test, and the sealing property and the storage stability of the dry film did not reach the target performance. As shown in Comparative Example 2, when the 10-hour half-life temperature was higher than 170°C, the start of the curing reaction was slow, and the low-temperature curability of the dry film did not reach the target performance. As shown in Comparative Example 3, when only a photopolymerization initiator was used, the surface irradiated with ultraviolet rays was cured, but the curing did not proceed to the inside of the dry film, so the low-temperature curability did not reach the target performance. As shown in Comparative Example 4, when the colorant was not included, the optical density did not reach the target performance, and when only the photopolymerization initiator was used, the transparency did not reach the target performance due to yellowing derived from the photoinitiator. Further, as shown in Comparative Examples 3 and 4, when only the photopolymerization initiator was used, the handleability did not reach the target performance. On the other hand, according to Examples 1 to 51, the dry film of the present invention maintains high levels of optical density, transparency, sealing property, low-temperature curability, storage stability, and handleability in a well-balanced manner as described in Tables 2 and 3. Therefore, it is possible to provide a dry film, a cured product, and an electronic component that are excellent in optical characteristics, sealing property of a semiconductor element, low-temperature curability, storage stability, and handleability.

Explanation of Symbols

[0083] 11: Dry film 12: Release liner 13: Protective film 20: Light-emitting element 21: Substrate 22: Test substrate

Claims

1. A dry film containing a radically polymerizable organic compound and a thermal radical polymerization initiator, wherein the dry film has a 10-hour half-life temperature of the thermal radical polymerization initiator of 60°C or higher and 170°C or lower.

2. The dry film according to Claim 1, wherein the radically polymerizable organic compound contains a radically polymerizable polymer (a) having a glass transition temperature of -50°C or higher and 90°C or lower.

3. The dry film according to Claim 1, wherein the radically polymerizable organic compound contains at least one of a radically polymerizable oligomer (b) and a radically polymerizable monomer (c) that is liquid at normal temperature and pressure.

4. The storage elastic modulus (G'80) at 80°C obtained by dynamic viscoelasticity measurement is 5×10 ４ Pa to 5×10 ７ Pa, and the dry film according to claim 2 or 3, characterized in that.

5. The dry film according to Claim 4, wherein the loss tangent (tanδ80) at 80°C obtained by dynamic viscoelasticity measurement is 0.3 to 0.

7.

6. The dry film according to Claim 5, wherein the dynamic friction coefficient of the surface of the dry film is 0.5 or less.

7. The dry film according to Claim 6, which contains 0.1 to 80% by mass of a colorant in 100% by mass of the total solid content of the dry film.

8. An electronic device comprising a cured product of the dry film according to Claim 7.

Images