TW202336073A - Curable resin composition, adhesive, cured product, camera module, and electronic device - Google Patents

Abstract

The purpose of the present invention is to provide a curable resin composition that cures rapidly and can reduce the occurrence of bleed. That is, this curable resin composition comprises an epoxy resin, a latent curing agent, and an imidazole derivative having a melting point of not more than 180 DEG C.

Description

Curable resin compositions, adhesives, hardened materials, photographic modules and electronic equipment

The present invention relates to a curable resin composition, adhesive, cured product, photography module and electronic equipment.

In recent years, electronic devices such as portable terminal devices and home appliances equipped with photographic modules have been used. When manufacturing electronic equipment equipped with photographic modules, one method of arranging parts at a high density is the flip chip packaging method. In the flip-chip packaging method, there is a step of fixing, for example, a photography module and a substrate with an adhesive or the like.

The adhesive used in the flip-chip packaging method is required to harden quickly from the perspective of improving work efficiency. From the viewpoint of meeting this requirement, products containing an epoxy resin and a hardener have been designed so far (see, for example, Patent Documents 1 and 2).

Patent Document 1 is Japanese Patent Application Laid-Open No. 2014-156519, and Patent Document 2 is Japanese Patent Application Laid-Open No. 2010-111711.

In the flip-chip packaging method, the adhesive is used, for example, to fill the gap between the semiconductor and the substrate. At this time, the liquid component of the adhesive (that is, the curable resin composition) may bleed out (so-called bleed). When bleeding occurs, there is a problem that the adhesive adheres to wiring other than the area where the adhesive should be bonded. For example, when leakage occurs during the production of a photography module, the adhesive diffuses from the bottom of a semiconductor chip such as a sensor to a microlens and leaks out. As a result, the liquid component of the adhesive seeps into the micro lens and the pads on the substrate, causing the photography module to malfunction.

Here, in the past, most electronic devices were relatively large, and the distance between components was also relatively large. Therefore, even if bleeding occurs, it is difficult for the components of the adhesive to reach members other than the parts to be bonded with the adhesive. On the other hand, in the small electronic equipment required in recent years, it is increasingly necessary to consider the influence of leakage.

The object of the present invention is to provide a curable resin composition that hardens quickly and can reduce bleeding, as well as adhesives, cured products, photographic modules and electronic equipment using the same.

In order to achieve the above object, one embodiment of the present invention is as follows. (1) A curable resin composition containing an epoxy resin, a latent hardener and an imidazole derivative with a melting point of 180°C or lower. (2) The curable resin composition according to (1), wherein the imidazole derivative has a melting point of 160°C or lower. (3) The curable resin composition according to (1) or (2), wherein the imidazole derivative has a melting point of less than 100°C. (4) An adhesive containing the curable resin composition according to any one of (1) to (3). (5) A cured product obtained from the curable resin composition according to any one of (1) to (3). (6) A photography module having a hardened object as in (5). (7) An electronic device having a photography module as in (6).

Cross-reference with related documents: This application claims priority based on Japanese Patent Application No. 2022-031853 filed on March 2, 2022, and is included in this specification by citing this basic application.

According to the present invention, it is possible to provide a curable resin composition that hardens quickly and can reduce bleeding, as well as adhesives, cured products, photographic modules and electronic equipment using the same.

(summary) Figure 1 is used to illustrate the occurrence of bleeding during the manufacturing of photographic modules. For example, when manufacturing a photography module, the heated curable resin composition 70 is supplied to the gap between the substrate 40 and the image sensor 50 . Thereafter, the curable resin composition is cured by heating the substrate 40 and the image sensor 50 .

Heating when supplying the curable resin composition is performed in order to reduce the viscosity of the curable resin composition so that the curable resin composition can be easily supplied. Therefore, during the period of heating until complete curing, the curable resin composition oozes out onto the substrate 40 from the opening of the gap between the substrate 40 and the image sensor 50 , thus bleeding occurs.

The inventors studied the reasons for the occurrence of exudation. As a result, it was found that the components exuded from the opening onto the substrate were low molecular components contained in the curable resin composition.

Here, the inventors examined a component ratio that can be cured before low-molecular components bleed out from the curable resin composition with reduced viscosity. As a result of the investigation, it was found that by using a specific imidazole derivative in combination with a latent hardener, the hardening can be accelerated and the occurrence of bleeding can be reduced, and the present invention was completed.

(hardening resin composition) The curable resin composition according to the embodiment contains an epoxy resin, a latent hardener and an imidazole derivative, preferably a filler, and further contains other components as necessary.

＜Epoxy resin＞ The epoxy resin system imparts curability, heat resistance, and adhesiveness, and is contained in order to impart durability to the cured product of the curable resin composition. The epoxy resin is not particularly limited as long as it is a variety of epoxy resins generally used for semiconductors, and can be appropriately selected according to the purpose.

Examples of the epoxy resin include bisphenol A type epoxy resin, brominated bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol A type/bisphenol F type epoxy resin, and naphthalene type epoxy resin. , biphenyl epoxy resin, novolac epoxy resin, aminophenol epoxy resin, alicyclic epoxy resin, ether or polyether epoxy resin, epoxy resin containing ethylene oxide ring , multifunctional epoxy resin, etc. These may be used alone or in combination of two or more. Among these, from the viewpoint of low viscosity and moisture resistance reliability of the curable resin composition, bisphenol A type/bisphenol F type epoxy resin, naphthalene type epoxy resin, and polyfunctional type epoxy resin are preferred. Epoxy resin.

As the epoxy resin, a synthetic product or a commercially available product can be used. Examples of commercially available products include YD-128, YD-825GS (bisphenol A type epoxy resin, manufactured by Nippon Steel Chemical Co., Ltd.), YDF8170, and YDF870GS (bisphenol F type epoxy resin, manufactured by Nippon Steel Chemical Co., Ltd. Co., Ltd.), EPICLON (registered trademark) EXA 835LV (bisphenol A type/bisphenol F type epoxy resin, made by DIC Co., Ltd.), EPICLON (registered trademark) HP 4032D (naphthalene type epoxy resin, DIC Co., Ltd. manufactured), jer (registered trademark) 630D (multifunctional epoxy resin, manufactured by Mitsubishi Chemical Co., Ltd.), etc.

The content of the epoxy resin is not particularly limited and can be appropriately selected according to the purpose. From the viewpoint of viscosity and processability, for the curable resin composition excluding the filler, 40% by mass to 95% by mass is preferred. More preferably, it is 45 mass % - 90 mass %, and still more preferably, it is 50 mass % - 88 mass %.

＜Latent hardener＞ The latent curing agent is contained in order to promote curing of the curable resin composition. Latent hardener is a solid that is insoluble at room temperature and is softened by heating and the reaction proceeds. Examples of latent curing agents include microencapsulated curing agents in which microcapsules are filled with a curing agent.

As the latent hardener, a synthetic product or a commercially available product can be used. Examples of commercially available latent hardeners that are not microencapsulated include FXE-1000, FUJICURE FXB-1050, FXR1121, and FXR1020 of the FUJICURE series (the above products are manufactured by T&K TOKA Co., Ltd.). Commercially available products of microencapsulated latent hardeners include NOVACURE (registered trademark) series HXA9322HP, HX3721, HX3088, HXA3932HP, HXA3922HP, HXA5945 HP, and HXA5911HP (the above are manufactured by Asahi Kasei Co., Ltd.). These may be used alone or in combination of two or more. Among them, NOVACURE HXA9322HP is preferred from the viewpoint of increasing the hardening speed.

The content of the latent hardener is not particularly limited and can be appropriately selected according to the purpose. From the viewpoint of viscosity and moisture resistance reliability, for the curable resin composition other than the filler, 2% by mass to 30% by mass is preferred. mass%, more preferably 5 mass% to 25 mass%.

＜Imidazole Derivatives＞ The imidazole derivative is contained in order to accelerate hardening of the curable resin composition. In the present invention, the imidazole derivative is a solid that is insoluble at room temperature and is soluble by heating, thereby accelerating the hardening of the curable resin composition.

The melting point of the imidazole derivative is 180°C or lower, preferably 160°C or lower, and more preferably less than 100°C. The imidazole derivative having a melting point less than 100°C means that it is liquid at 100°C. If the melting point of the imidazole derivative is 180°C or lower, the occurrence of bleeding can be reduced. Moreover, the melting point of the imidazole derivative is preferably 10°C or higher.

Examples of imidazole derivatives with a melting point of 180°C or lower include 2-methylimidazole (melting point: 142°C), 2-undecylimidazole (melting point: 71-75°C), and 2-heptadecanylimidazole (melting point: 89°C) ), 2-ethyl-4-methylimidazole (melting point: 47-54℃), 2-phenylimidazole (melting point: 142-148℃), 2-phenyl-4-methylimidazole (melting point: 180℃ ), 2-phenyl-4-methyl-1H-imidazole (melting point: 174-184℃), 2,3-dihydro-1H-pyrrole[1,2-a]benzimidazole (melting point: 115℃) , 1-[([1,1'-biphenyl]-2-yl)oxy]-3-(2-methyl-1H-imidazol-1-yl)propan-2-ol (1-[([1 ,1'-biphenyl]-2-yl)oxy]-3-(2-methyl-1H-imidazole-1-yl)propan-2-ol) (melting point: 160°C), etc. These may be used alone or in combination of two or more. Among these, from the viewpoint of the temperature during use, hardening temperature, hardening speed, and viscosity stability of the paste, 2-undecylimidazole, 2-heptadecanylimidazole, (1-[( [1,1'-biphenyl]-2-yl)oxy]-3-(2-methyl-1H-imidazol-1-yl)propan-2-ol.

The content of the imidazole derivative is not particularly limited and can be appropriately selected according to the purpose. From the viewpoint of curing speed and viscosity stability of the paste, 2 mass % is preferred for curable resin compositions other than fillers. ~30 mass%, more preferably 3 mass% to 25 mass%, further preferably 3 mass% to 20 mass%.

The ratio of the content of the imidazole derivative to the content of the latent hardener (imidazole derivative/latent hardener) is preferably 0.02 to 5, more preferably 0.05 to 3. If the ratio (imidazole derivative/latent hardener) is within this range, the occurrence of exudation will be reduced.

＜Filler＞ The filler is contained in order to adjust the characteristics (mainly linear expansion coefficient, elastic modulus, and water absorption) of the cured product of the curable resin composition. The type of filler is not particularly limited and can be appropriately selected according to the purpose. Examples include silicon dioxide such as fused silicon dioxide and crystalline silicon dioxide; calcium carbonate, clay, alumina, silicon nitride, silicon carbide, and nitride. Boron, calcium silicate, potassium titanate, aluminum nitride, beryllium oxide, zirconia, zircon, forsterite, talc, spinel, mullite, titanium dioxide, aluminum hydroxide, magnesium hydroxide, boric acid Zinc, zinc molybdate, etc. These may be used alone or in combination of two or more. Among these, a silica filler is preferable from the viewpoint of stability and heat resistance.

The filler may be surface-treated. The surface treatment agent is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include a silane coupling agent and the like.

The silane coupling agent is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include epoxy type, methacrylic type, amino type, vinyl type, glycidoxy type, mercapto type, and the like.

The volume average particle diameter of the filler is not particularly limited and can be appropriately selected according to the purpose. For example, 0.03 μm to 10 μm is preferred, 0.05 μm to 5 μm is more preferred, and 0.05 μm to 2 μm is more preferred. In this embodiment, the volume average particle size is the particle size at which the volume cumulative particle size distribution measured using the laser diffraction method is 50%.

The shape of the filler is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include spherical, irregular, scaly, etc., and spherical is preferred.

The content of the filler is not particularly limited and can be appropriately selected depending on the purpose.

＜Other ingredients＞ Other components are not particularly limited as long as they are contained in general curable resin compositions and can be appropriately selected according to the purpose. Examples include colorants such as carbon black and titanium black, ion trapping agents, leveling agents, and antioxidants. , defoamer, thixotrope, viscosity adjuster, flame retardant, solvent, etc. These may be used alone or in combination of two or more.

The content of other ingredients is not particularly limited and can be appropriately selected depending on the purpose.

The curable resin composition of the present invention can suppress bleeding for the following two reasons. First, by containing an imidazole derivative that is solid at room temperature, the curable resin composition can easily adhere to the unevenness of the substrate, so the bleeding of the curable resin composition can be suppressed. Secondly, by containing a latent hardener, the latent hardener is eluted when heated, thereby accelerating hardening. That is, the curable resin composition can be hardened before the curable resin composition bleeds out.

-Method for manufacturing curable resin composition- The manufacturing method of the curable resin composition is not particularly limited and can be appropriately selected depending on the purpose. For example, a method of mixing and stirring the above-mentioned components can be used.

In addition, the ingredients can be mixed at the same time, or a part of the ingredients can be mixed first and then the remaining ingredients can be mixed. For epoxy resin, if it is difficult to disperse the filler uniformly, you can mix the epoxy resin and the filler first, and then mix the remaining ingredients.

The device used for mixing is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include a roller mill.

(adhesive) The adhesive of this embodiment contains the above-mentioned curable resin composition.

(hardened substance) The cured product of this embodiment is a cured product obtained by curing the above-mentioned curable resin composition. The shape and thickness of the hardened material are not particularly limited and can be appropriately selected according to the purpose.

Examples of methods for curing the curable resin composition include heating. The heating temperature is not particularly limited and can be appropriately selected according to the purpose. It is preferably 80°C to 150°C, more preferably 100°C to 130°C. The heating time is not particularly limited and can be appropriately selected depending on the purpose. Examples thereof include 1 minute to 2 hours.

(Photography module) The photography module of this embodiment has the above-mentioned hardened object. Here, FIG. 2 is used to describe the photography module of this embodiment. The photography module shown in Figure 2 has a lens barrel 10, a housing 20, an infrared filter 30, a substrate 40, an image sensor 50, and a micro lens 55. The lens barrel 10 is a member that holds a plurality of lenses 11 . The lens barrel 10 is fixed to the housing 20 . The lower end of the housing 20 is fixed to the top surface of the base plate 40 . The infrared filter 30 that filters the light passing through the lens 11 is disposed on the housing 20 . The substrate 40 is connected to the image sensor 50 through the bumps 51 . A hardener 60 for hardening the above-mentioned hardenable composition is provided between the substrate 40 and the image sensor 50 .

When manufacturing the photography module, the curable resin composition is supplied through the gap between the substrate 40 and the image sensor 50 . Thereafter, the curable resin composition is hardened by heating the photography module. By hardening of the curable resin composition, the gap between the substrate 40 and the image sensor 50 is closed. Since the curable resin composition of the present invention can reduce bleeding, it can prevent contamination of the micro lens 55 and the soldering pads (not shown) on the substrate 40 .

In addition, the supply method of the curable resin composition is not particularly limited and can be appropriately selected according to the purpose. Examples thereof include a jet dispenser, an air dispenser, and the like. In addition, when supplying the curable resin, the curable resin composition may be heated in order to reduce the viscosity of the curable resin composition. The temperature during heating is not particularly limited as long as the curable resin composition is not hardened, and can be appropriately selected depending on the purpose. Examples thereof include 40°C to 60°C.

(Electronic equipment) The electronic device of this embodiment has the above-mentioned photography module, and further has other components as needed. Other components are not particularly limited and can be appropriately selected depending on the purpose. Examples of electronic equipment include portable terminal devices and home appliances.

Example: (Examples 1 to 14, Comparative Examples 1 to 4) The component ratios described in Tables 1 to 4 were mixed and homogenized using a three-roller mill to obtain a curable resin composition. In addition, unless otherwise noted, the numerical values in the table represent parts by mass.

Table 1 Example 1 2 3 4 5 Epoxy resin Bisphenol A/Bisphenol F 29.8 29.8 29.8 29.8 29.8 Naphthalene type - - - - - polyfunctional - - - - - latent hardener latent hardener 1 11.7 - - - - latent hardener 2 - 11.7 - - - latent hardener 3 - - 11.7 - - latent hardener 4 - - - 11.7 latent hardener 5 - - - - 11.7 Latent hardener 6 - - - - - Latent hardener 7 - - - - - Imidazole derivatives Imidazole derivatives 1 1.7 1.7 1.7 1.7 1.7 Imidazole derivative 2 - - - - - Imidazole derivative 3 - - - - - Imidazole derivatives 4 - - - - - Imidazole derivative 5 - - - - - Imidazole derivative 6 - - - - - Imidazole derivative 7 - - - - - Imidazole derivatives 8 - - - - - filler 55.0 55.0 55.0 55.0 55.0 other ingredients thixotropic agent 1.8 1.8 1.8 1.8 1.8 total 100.0 100.0 100.0 100.0 100.0 Melting point of imidazole derivatives (℃) 69-74 69-74 69-74 69-74 69-74 Evaluation results DSC peak temperature (℃) 122.6 121.7 123.3 124.0 122.5 Bleeding distance (mm) 0.0 0.1 0.0 0.0 0.0 Is there any leakage? ◎ ◎ ◎ ◎ ◎ Hardening ○ ○ ○ ○ ○

Table 2 Example 6 7 8 9 10 Epoxy resin Bisphenol A/Bisphenol F 29.8 30.5 29.8 29.8 29.8 Naphthalene type - - - - - polyfunctional - - - - - latent hardener latent hardener 1 - - 11.7 11.7 11.7 latent hardener 2 - - - - - latent hardener 3 - - - - - latent hardener 4 - - - - latent hardener 5 - - - - - Latent hardener 6 11.7 - - - - Latent hardener 7 - 11.0 - - - Imidazole derivatives Imidazole derivatives 1 1.7 1.7 - - - Imidazole derivative 2 - - 1.7 - - Imidazole derivative 3 - - - 1.7 - Imidazole derivatives 4 - - - - 1.7 Imidazole derivative 5 - - - - - Imidazole derivative 6 - - - - - Imidazole derivative 7 - - - - - Imidazole derivatives 8 - - - - - filler 55.0 55.0 55.0 55.0 55.0 other ingredients thixotropic agent 1.8 1.8 1.8 1.8 1.8 total 100.0 100.0 100.0 100.0 100.0 Melting point of imidazole derivatives (℃) 69-74 69-74 86-91 137-147 174-184 Evaluation results DSC peak temperature (℃) 120.3 116.8 123.4 121.6 121.4 Bleeding distance (mm) 0.4 0.5 0.1 0.7 0.7 Is there any leakage? ○ ○ ◎ ○ ○ Hardening ○ ○ ○ ○ ○

Table 3 Example 11 12 13 14 Epoxy resin Bisphenol A/Bisphenol F 29.8 23.0 25.1 70.2 Naphthalene type - 6.8 - - polyfunctional - - 4.7 - latent hardener latent hardener 1 11.7 11.7 11.7 26.0 latent hardener 2 - - - - latent hardener 3 - - - - latent hardener 4 - - - - latent hardener 5 - - - - Latent hardener 6 - - - - Latent hardener 7 - - - - Imidazole derivatives Imidazole derivatives 1 - 1.7 1.7 3.8 Imidazole derivative 2 - - - - Imidazole derivative 3 - - - - Imidazole derivatives 4 - - - - Imidazole derivative 5 1.7 - - - Imidazole derivative 6 - - - - Imidazole derivative 7 - - - - Imidazole derivatives 8 - - - - filler 55.0 55.0 55.0 - other ingredients thixotropic agent 1.8 1.8 1.8 - total 100.0 100.0 100.0 100.0 Melting point of imidazole derivatives (℃) 160.0 69-74 69-74 69-74 Evaluation results DSC peak temperature (℃) 121.5 120.1 121.4 119.9 Bleeding distance (mm) 0.6 0.0 0.0 0.0 Is there any leakage? ○ ◎ ◎ ◎ Hardening ○ ○ ○ ○

Table 4 Comparative example 1 2 3 4 Epoxy resin Bisphenol A/Bisphenol F 24.7 29.8 29.8 29.8 Naphthalene type - - - - polyfunctional - - - - latent hardener latent hardener 1 18.5 11.7 11.7 11.7 latent hardener 2 - - - - latent hardener 3 - - - - latent hardener 4 - - - - latent hardener 5 - - - - Latent hardener 6 - - - - Latent hardener 7 - - - - Imidazole derivatives Imidazole derivatives 1 - - - - Imidazole derivative 2 - - - - Imidazole derivative 3 - - - - Imidazole derivatives 4 - - - - Imidazole derivative 5 - - - - Imidazole derivative 6 - 1.7 - - Imidazole derivative 7 - - 1.7 - Imidazole derivatives 8 - - - 1.7 filler 55.0 55.0 55.0 55.0 other ingredients thixotropic agent 1.8 1.8 1.8 1.8 total 100.0 100.0 100.0 100.0 Melting point of imidazole derivatives (℃) - 248-258 184-188 251.0 Evaluation results DSC peak temperature (℃) 119.5 125.6 125.0 126.0 Bleeding distance (mm) 1.3 0.6 0.3 0.6 Is there any leakage? ╳ ○ ○ ○ Hardening ○ ╳ ╳ ╳

The epoxy resins used in Examples and Comparative Examples are as follows. ‧Bisphenol A type/Bisphenol F type (EPICLON (registered trademark) EXA 835LV, manufactured by DIC Co., Ltd.) ‧Naphthalene type (EPICLON (registered trademark) HP 4032D, manufactured by DIC Co., Ltd.) ‧Polyfunctional type (jer (registered trademark) 630D, manufactured by Mitsubishi Chemical Co., Ltd.)

The latent hardener used in the Examples and Comparative Examples is as follows. Latent hardeners 1 to 6 each contain approximately 67% by mass of epoxy resin, and latent hardener 7 contains approximately 50% by mass of epoxy resin. The value of latent hardener in the table is the total amount including epoxy resin. ‧Latent hardener 1 (NOVACURE (registered trademark) HXA9322HP, manufactured by Asahi Kasei Co., Ltd.) ‧Latent hardener 2 (NOVACURE (registered trademark) HX3721, manufactured by Asahi Kasei Co., Ltd.) ‧Latent hardener 3 (NOVACURE (registered trademark) HX3088, manufactured by Asahi Kasei Co., Ltd.) ‧Latent hardener 4 (NOVACURE (registered trademark) HXA3932HP, manufactured by Asahi Kasei Co., Ltd.) ‧Latent hardener 5 (NOVACURE (registered trademark) HXA3922HP, manufactured by Asahi Kasei Co., Ltd.) ‧Latent hardener 6 (NOVACURE (registered trademark) HXA5945HP, manufactured by Asahi Kasei Co., Ltd.) ‧Latent hardener 7 (NOVACURE (registered trademark) HXA5911HP, manufactured by Asahi Kasei Co., Ltd.)

The imidazole derivatives used in the Examples and Comparative Examples are as follows. ‧Imidazole derivative 1 (2-undecylimidazole, CUREZOL C11Z, manufactured by Shikoku Chemical Industry Co., Ltd.) ‧Imidazole derivative 2 (2-heptadecanyl imidazole, CUREZOL C17Z, manufactured by Shikoku Chemical Industry Co., Ltd.) ‧Imidazole derivative 3 (2-phenylimidazole, CUREZOL 2PZ, manufactured by Shikoku Chemical Industry Co., Ltd.) ‧Imidazole derivative 4 (2-phenyl-4-methyl-1H-imidazole, CUREZOL 2P4MZ, manufactured by Shikoku Chemical Industry Co., Ltd.) ‧Imidazole derivative 5((1-[([1,1'-biphenyl]-2-yl)oxy]-3-(2-methyl-1H-imidazol-1-yl)propan-2-ol, OPPG-2MZ, synthesized according to the synthesis method of Compound 1 in International Publication No. 2021/201060 manual) ‧Imidazole derivative 6 (2,4-diamino-6-(2’-methylimidazolyl)ethyl-1,3,5-triazine, CUREZOL 2MZA, manufactured by Shikoku Chemical Industry Co., Ltd.) ‧Imidazole derivative 7 (2,4-diamino-6-[2'-undecylimidazolyl-(1')]-ethyl-s-triazine, CUREZOL C11Z-A, Shikoku Chemical Industry Co., Ltd. limited company) ‧Imidazole derivative 8 (2,4-diamino-6-(2'-methylimidazolyl)ethyl-1,3,5-triazine, CUREZOL 2MZA-PW, manufactured by Shikoku Chemical Industry Co., Ltd. )

The fillers and other components (thixotropic agent) used in the examples and comparative examples are as follows. ‧Filler (silica, SO-E5, particle size: 1.3~1.7μm, manufactured by Admatechs Co., Ltd.) ‧Thixotropic agent (silica nanofiller, AEROSIL (registered trademark) R805, particle size: 12nm, manufactured by Japan Aerosil Co., Ltd.) In addition, the particle sizes of fillers and thixotropic agents are different. The particle size of the filler is several hundred nm to several tens of μm, whereas the particle size of the thixotropic agent is about several tens of nm.

The DSC peak temperature and bleeding distance of the obtained curable resin composition were measured, and the presence or absence of bleeding and curability were evaluated. The measurement results and evaluation results are recorded together in Tables 1 to 4.

＜Distance of seepage, presence or absence of seepage＞ The ceramic substrate was subjected to oxygen plasma treatment (300W, 1 minute). On this oxygen plasma-treated ceramic substrate, 1 mg of each curable resin composition filled into the syringe was extruded and poured, and then left at 60° C. for 3 hours. After standing, an optical microscope was used to measure the distance in which the curable resin composition bleeds out (bleedout distance, that is, bleedout length). In addition, the presence or absence of bleeding (presence or absence of bleeding) was evaluated based on the following evaluation criteria. -Evaluation criteria- ◎: Bleeding distance is 0mm～less than 0.1mm ○: Bleeding distance is 0.1mm to less than 1mm ╳: Bleeding distance is 1mm or more

＜DSC peak temperature, hardenability (short time hardening at 150°C)＞ About 5 mg of each curable resin composition was dropped into an aluminum pan. This aluminum plate was set on a DSC (DSC 204 F1 Phoenix, manufactured by BRUKER Co., Ltd.), and the temperature was raised from 25°C to 250°C at 10°C/min to obtain a DSC chart. Read the DSC exothermic peak temperature from the obtained DSC chart. Based on the following evaluation criteria, the DSC exothermic peak temperature is evaluated as hardenability (short-time hardening at 150°C). In addition, if the DSC exothermic peak temperature is less than 125°C, it can be hardened at 150°C for a short time. -Evaluation criteria- ○: DSC heat release peak temperature is less than 125℃ ╳: DSC heat release peak temperature is above 125℃

As shown in Tables 1 to 4, the curable resin compositions of the Examples had good curability and the evaluation of the occurrence of bleeding was "○" or above. From this, it is obvious that the curable resin composition of any embodiment hardens quickly and can reduce the occurrence of bleeding. On the other hand, Comparative Example 1, which did not contain an imidazole derivative, had good curability, but bleeding occurred. In addition, Comparative Examples 2 to 4 containing imidazole derivatives with a melting point exceeding 180°C can reduce bleeding, but hardening takes time. From this, it is obvious that a curable resin composition containing both a latent hardener and an imidazole derivative with a melting point of 180° C. or lower hardens quickly and can reduce the occurrence of bleeding.

The embodiments and examples of the present invention have been described above. However, these are only examples and are not intended to limit the scope of the invention. The embodiment can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the present invention. The embodiments and their modifications are included in the scope and gist of the invention, and are also included in the scope of the invention described in the patent application and their equivalents.

10: Lens barrel 11: Lenses 20: Shell 30:Infrared filter 40:Substrate 50:Image sensor 51: Bump 55:Micro lens 60:hardened material 70: Curable resin composition

[Fig. 1] A schematic diagram showing an example of the manufacturing steps of a photographic module according to an embodiment of the present invention. [Fig. 2] A schematic cross-sectional view showing an example of a photography module according to an embodiment of the present invention.

40:Substrate

50:Image sensor

51: Bump

55:Micro lens

70: Curable resin composition

Claims (7)

A curable resin composition containing an epoxy resin, a latent hardener and an imidazole derivative with a melting point below 180°C. The curable resin composition of claim 1, wherein the imidazole derivative has a melting point of 160°C or lower. The curable resin composition of claim 1 or 2, wherein the melting point of the imidazole derivative is less than 100°C. An adhesive containing the curable resin composition according to claim 1 or 2. A cured product obtained from the curable resin composition of claim 1 or 2. A photography module having a hardened object as claimed in claim 5. An electronic device having a photography module as claimed in claim 6.