Resin composition, conductive adhesive, adhesive structure, and electronic component

Abstract

The present invention provides a resin composition having little influence on the curing time and capable of prolonging the pot life. The present invention provides a resin composition containing an epoxy resin, a latent curing agent, and a metal oxide, wherein the compressibility of the metal oxide as obtained by formula (A) below is 15% to 50%.　(A) Compressibility (%) = ((Tap density-Apparent density)／ Tap density) x 100 By using said resin composition, it is possible to provide a conductive adhesive, an adhesive structure, and an electronic component having an excellent pot life.

Description

Resin compositions, conductive adhesives, adhesive structures, and electronic components

[0001] The present invention relates to resin compositions, conductive adhesives, adhesive structures, and electronic components.

[0002] Conventionally, resin compositions mainly composed of compounds having epoxy groups have been used as connecting adhesives to link circuit components and circuit boards in electronic devices.

[0003] In recent years, with the expansion of the RFID (Radio Frequency Identification) market, the demand for adhesives used to connect circuit components contained in RFID media such as RFID tags to circuit boards has also increased. Furthermore, from the perspective of improving the productivity of electronic devices and RFID media, there is a need for adhesives that can connect circuit components and circuit boards in a short time, and therefore resin compositions with short curing times are required.

[0004] However, resin compositions with short curing times have the disadvantage of having a very short pot life and poor workability. To improve this drawback, for example, Patent Document 1 describes a conductive adhesive in which the pot life can be extended by suppressing thickening during storage through the addition of morpholines. Patent Document 2 also discloses a conductive adhesive in which the shortening of the pot life is prevented by mixing silica surface-treated with an imidazolesilane coupling agent with an epoxy resin.

[0005] Incidentally, in the field of adhesive compositions, there are various challenges other than improving pot life, and one proposed solution to these challenges is the addition of metal oxides. For example, Patent Document 2 describes how mixing silica, a metal oxide that has undergone surface treatment, with epoxy resin improves not only pot life but also adhesion between the epoxy resin and metal electrodes. Furthermore, Patent Document 3 describes how using magnesium oxide or titanium oxide as components of an adhesive composition can suppress corrosion of the substrate by acids derived from photocation generators used as polymerization catalysts, thereby proposing an adhesive composition that can prevent a decrease in reliability.

[0006] International Publication No. 2015 / 129377, Japanese Unexamined Patent Application Publication No. 2007-204673, Japanese Unexamined Patent Application Publication No. 2006-199778

[0007] Thus, by adding a metal oxide to the resin composition, various property improvements can be expected. On the other hand, as a cause of the shortening of the pot life, the curing of the resin composition starts due to the slight generation of an acid from a latent curing agent which is one of the components of the resin composition during storage. In Patent Document 3, it is described that corrosion of a substrate by an acid can be suppressed by a metal oxide, but improvement of the pot life is not mentioned, and according to the study by the present inventors, it did not actually reach improvement of the pot life.

[0008] Therefore, an object of the present invention is to provide a resin composition which has little influence on the curing time and can have a long pot life.

[0009] As a result of intensive studies in view of the above circumstances, the present inventors have found that in order to suppress curing by an acid generated during storage from a latent curing agent in a resin composition, by containing a powder of a specific metal oxide in the resin composition, the acid is trapped in the space in the powder of the metal oxide and the curing of the resin composition is suppressed, and thus the present invention has been completed.

[0010] The present invention provides a resin composition containing an epoxy resin, a latent curing agent, and a metal oxide, wherein the resin composition has a compression ratio determined by the following formula (A) of the metal oxide of 15% or more and 50% or less. Compression ratio (%) = ((tap density - apparent density) / tap density) × 100... (A)

[0011] The present invention also provides a conductive adhesive containing the resin composition further containing conductive particles. <00000�9>

[0012] The present invention also provides an adhesive structure in which adherent members are adhered via the conductive adhesive, and an electronic component using the conductive adhesive.

[0013] According to the present invention, it is possible to provide a resin composition that has little influence on the curing time and can extend the pot life, a conductive adhesive having excellent pot life using the same, an adhesive structure, and an electronic component.

[0014] Hereinafter, the present invention will be described based on preferred embodiments. The resin composition of the present invention is a resin composition containing an epoxy resin, a latent curing agent, and a metal oxide, wherein the compression ratio determined by the following formula (A) of the metal oxide is 15% or more and 50% or less. Compression ratio (%) = ((tap density - apparent density) / tap density) × 100... (A)

[0015] The metal oxide used in the resin composition of the present invention suppresses an unintended curing reaction by capturing an acid generated from the latent curing agent during storage of the resin composition. Therefore, it is necessary that the metal oxide used can secure an appropriate space between particles. Specifically, it is more preferable that the compression ratio determined by the formula (A) of the metal oxide is 18% or more and 45% or less, and particularly preferably 20% or more and 40% or less. The compression ratio is a measure of the fluidity of the powder, and the larger the value, the worse the fluidity, that is, there is a space between the particles in the powder. In the present invention, an acid unintentionally generated from the latent curing agent is captured in the space in the powder of the metal oxide, the curing reaction of the resin composition is suppressed, and the pot life can be extended. When the compression ratio of the metal oxide is less than 15%, the space in the powder of the metal oxide becomes too narrow to capture an acid generated unintentionally, and when it exceeds 50%, the dispersibility of the metal oxide in the resin composition deteriorates.

[0016] The apparent density in the formula (1) is 0.1 g / cm ３ , ３ , ３ , ３ , ３ , ３ , ３ or more and 0.7 g / cm ３ or less, particularly 0.3 g / cm ３ or more and 0.6 g / cm ３ or less is preferable. Also, the tap density is 0.2 g / cm ３ or more and 0.9 g / cm ３ or less, particularly 0.25 g / cm ３ or more and 0.8 g / cm ３It is preferably as follows. By having the density within this range, the compression rate of the above-mentioned metal oxide can be achieved, so that the acid generated unintentionally can be effectively captured. Note that the apparent density and the tapped density can be measured by a method conforming to JIS K 5101-12-2:2004.

[0017] In addition to the above compression rate, the specific surface area of the metal oxide is 0.5 m ２ / g or more and 100 m ２ / g or less, particularly preferably 2 m ２ / g or more and 30 m ２ / g or less. By having the specific surface area of the metal oxide within this range, the acid generated unintentionally can be captured, so that the curing reaction of the resin composition does not proceed and the pot life can be lengthened. Note that the specific surface area can be measured by the BET method.

[0018] The metal oxide may be synthesized by a known method or a commercially available product as long as it has the above-mentioned characteristics. Examples of such metals of the metal oxide include Ti, Al, Mg, Zr, and Zn. Among these, the metal oxide of the present invention is particularly preferably titanium oxide or aluminum oxide from the viewpoint of having little influence on the curing time and being easily capable of capturing the acid generated unintentionally.

[0019] The addition amount of the metal oxide of the present invention is determined with respect to the amount of the latent curing agent described later, and the amount of the metal oxide with respect to the latent curing agent is preferably an amount such that the mass ratio is 25 to 250, and more preferably an amount such that the mass ratio is 50 to 150. If the mass ratio of the metal oxide to the latent curing agent is less than 25, it becomes difficult to obtain the effect of extending the pot life. On the other hand, if this mass ratio exceeds 250, although the pot life extends, the gel time becomes long and curing becomes difficult to occur.

[0020] The latent curing agent used in the resin composition of the present invention can be any compound capable of generating a cationic species or Lewis acid upon heating, such as aromatic sulfonium salts, thiophene salts, thiolanium salts, benzylammonium, pyridinium salts, hydrazinium salts, carboxylic acid esters, sulfonic acid esters, and amineimides. Among these, aromatic sulfonium salts are preferred because the compounds are relatively stable and the curing time can be shortened.

[0021] The latent curing agent can be a commercially available product. Examples of such commercially available products include the San-Aid® series from Sanshin Chemical Industry Co., Ltd., such as SI-L85, SI-L110, SI-L145, SI-L160, SI-H15, SI-H20, SI-H25, SI-H40, SI-H50, SI-60L, SI-80L, San-Aid SI-100L, San-Aid SI-60, San-Aid SI-80, and San-Aid SI-100; TA-60, TA-100, and TA-110 from Sun-Apro Co., Ltd.; and Adeka Opton CP-66 (counterion: SbF) from ADEKA Corporation. ６ Examples include Adeka Opton CP-77; TAG-2678, TAG-2713, TAG-2172 from KING INDUSTRIES INC.; FC-520 from 3M; and CI-2921, CI-2920, CI-2946, CI-3128, CI-2624, CI-2639, CI-2064 from Nippon Soda Co., Ltd. These latent curing agents may be used individually or in mixtures of two or more types.

[0022] The epoxy resin used in the resin composition of the present invention may be any epoxy resin commonly used as an adhesive for connecting electronic devices and RFID media, and is preferably a compound having two or more epoxy groups in one molecule. Specific examples of such compounds include novolac resins such as phenol novolac and cresol novolac; polyhydric phenol compounds such as bisphenol A, bisphenol F, bisphenol AD, resorcinol, and bishydroxydiphenyl ether; polyhydric alcohol compounds such as ethylene glycol, neopentyl glycol, glycerin, trimethylolpropane, and polypropylene glycol; polyamino compounds such as ethylenediamine, triethylenetetramine, and aniline; polyhydric carboxyl compounds such as adipic acid, phthalic acid, and isophthalic acid; glycidyl-type epoxy resins obtained by reacting these with epichlorohydrin or 2-methylepichlorohydrin; aliphatic epoxy resins such as dicyclopentadiene epoxy and butadiene dimer epoxy; and alicyclic epoxy resins such as 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate. Among these, polyvalent phenol compounds, glycidyl-type epoxy resins, and alicyclic epoxy resins are preferred due to their high adhesive strength, excellent heat resistance and electrical insulation properties, low melt viscosity, and the ability to connect at low pressure. Furthermore, to prevent ion migration, it is preferable to use high-purity products with reduced impurity ions (such as Na and Cl) and hydrolyzable chlorine.

[0023] Furthermore, these epoxy resins may be used individually or in mixtures of two or more types. In particular, when alicyclic epoxy resin is used alone and mixed with a curing agent, there is a risk that the resin itself may be altered by heat due to the large amount of heat generated by the reaction. Therefore, it is preferable to use alicyclic epoxy resin and glycidyl-type epoxy resin in combination. In this case, since a higher content of glycidyl-type epoxy resin results in a longer curing time, the mass ratio of alicyclic epoxy resin to glycidyl-type epoxy resin is preferably 99:1 to 25:75.

[0024] The epoxy resin content in the resin composition of the present invention is 30% by mass or more, preferably 50% by mass or more and 95% by mass or less.

[0025] In the resin composition of the present invention, the ratio (mass ratio) of the latent curing agent to the epoxy resin is preferably 1:1 to 1:1000, more preferably 1:1 to 1:900, and particularly preferably 1:1 to 1:800. By having the mass ratio of the latent curing agent to the epoxy resin within the above range, it is possible to shorten the curing time.

[0026] The resin composition of the present invention preferably has a pot life of 1 day or more, more preferably 2 days or more, and particularly preferably 3 days or more at 25°C, from the viewpoint of balancing storage stability and curability. In addition, the longer the pot life, the better, as long as the rapid curing properties of the resin composition can be maintained.

[0027] The resin composition of the present invention preferably has a gel time of less than 10 seconds at 150°C, and more preferably 0.5 to 8 seconds. Having a gel time within this range allows for a reduction in curing time without further compromising adhesion and connection reliability, thereby further improving the productivity of electronic devices, RFID media, etc., when used as a connecting adhesive. In this invention, gel time refers to the time from when the resin composition is heated to 150°C according to the hot plate method of JIS-C2161:2010 7.1.5 A until the resin composition gels and can no longer be stirred. A short gel time results in a faster curing reaction and a shorter curing time until completion. Conversely, a long gel time results in a slower curing reaction and a longer curing time until completion. Therefore, a resin composition with a short gel time can connect circuit components and circuit boards in a short time and is useful as a connecting adhesive.

[0028] The resin composition of the present invention may contain known additives, as long as they do not affect the pot life, adhesion, connection reliability, and curing time. Known additives include, for example, silane coupling agents, organic solvents, fillers, thixotropic agents, thickeners, devising agents, viscosity modifiers, leveling agents, antioxidants, tackifiers, waxes, heat stabilizers, stabilizers, anti-stabilizers, foaming agents, organic pigments, inorganic pigments, thermal conductors, electrical conductors, dyes, antistatic agents, moisture-permeable factory agents, water-repellent agents, hollow foams, flame retardants, colorants, water absorbers, moisture absorbers, deodorants, foam stabilizers, defoamers, antifungal agents, preservatives, anti-algal agents, pigment dispersants, blocking inhibitors, hydrolysis inhibitors, etc. In addition, other resins such as organic water-soluble compounds, inorganic water-soluble compounds, thermoplastic resins, and thermosetting resins can be used in combination in liquid or solid form. Typical additives include stabilizers, electrical conductors, thermal conductors, and thixotropic agents.

[0029] The resin composition of the present invention may contain a quaternary phosphonium salt represented by the following formula (1) as the stabilizer described above.

[0030]

[0031] In equation (1), R １ , R ２ , R ３ and R ４ These may be the same group or different groups, and each may independently be an alkyl group or a phenyl group (-C ６ H ５ ) represents R in equation (1). １ ~R ４ If is an alkyl group, an alkyl group having 1 to 16 carbon atoms is preferred. Also, in formula (1), X － This represents an anion, for example, F － , Cl － , I － , Br － SO ４ ２－ BF ４ － , PF ４ － SbF ６ － , (OC ２ H ５ ) ２P = O － , (C ６ H ５ ) ４ B － These are some examples.

[0032] In the resin composition of the present invention, methyltributylphosphonium dimethyl phosphate and methyltrioctylphosphonium dimethyl phosphate are preferred from the viewpoint of achieving stabilization with the addition of a small amount.

[0033] The amount of quaternary phosphonium salt added as a stabilizer is determined in relation to the amount of latent curing agent, and it is preferable that the mass ratio of the quaternary phosphonium salt to the latent curing agent is 0.001 to 1, and more preferably 0.005 to 0.8. If the mass ratio of the quaternary phosphonium salt to the latent curing agent is less than 0.001, it becomes difficult to obtain the effect of extending the pot life, while if this mass ratio exceeds 1, although the pot life is extended, the gel time tends to be longer and curing becomes less likely.

[0034] The resin composition of the present invention may contain conductive particles as the aforementioned electrical conductive agent. By including conductive particles, the resin composition of the present invention becomes a one-component conductive adhesive, which is particularly useful as a connecting adhesive that can connect circuit components and circuit boards in a short time without impairing adhesion and connection reliability. Examples of conductive particles include metal particles such as nickel, gold, silver, palladium, copper, and solder, as well as those that are inherently conductive, such as carbon particles. Another example is a core material particle with a metal film formed on its surface to impart conductivity.

[0035] In the resin composition of the present invention, when conductive particles are used as an electrical conductive agent, the average particle size of the conductive particles is preferably 0.1 μm to 1000 μm, and particularly preferably 0.5 to 100 μm. The average particle size of the conductive particles is appropriately selected according to the specific application of the resin composition of the present invention. However, when the resin composition of the present invention is used as a connecting adhesive, if the average particle size of the conductive particles is too small, conductivity becomes difficult, and if the average particle size of the conductive particles is too large, short circuits are more likely to occur. The average particle size of the conductive particles can be measured using the electrical resistance method.

[0036] Furthermore, there are no particular restrictions on the shape of the conductive particles. Generally, conductive particles can be in the form of powder or granules, but they may also be in other shapes, such as fibrous, hollow, plate-like, or needle-like, and may have numerous protrusions on their surface or be irregularly shaped. Among these, spherical conductive particles are particularly preferred because they have excellent packing properties.

[0037] When using conductive particles with a metal film formed on the surface of core material particles as an electrical conductive agent, methods for forming the metal film on the surface of the core material particles include dry methods using methods such as vapor deposition, sputtering, mechanochemical methods, and hybridization, and wet methods using methods such as electroplating and electroless plating. Alternatively, these methods may be combined to form the metal film on the surface of the core material particles.

[0038] When conductive particles with a metal film formed on the surface of core material particles are used as an electrical conductive agent, the core material particles used may be inorganic or organic. Examples of inorganic core material particles include metal particles such as gold, silver, copper, nickel, palladium, and solder, alloys, glass, ceramics, silica, metal or nonmetal oxides (including hydrated ones), metal silicates including aluminosilicates, metal carbides, metal nitrides, metal carbonates, metal sulfates, metal phosphates, metal sulfides, metal salts, metal halides, and carbon. Examples of organic core material particles include natural fibers and natural resins, thermoplastic resins such as polyethylene, polypropylene, polyvinyl chloride, polystyrene, polybutene, polyamide, polyacrylic acid esters, polyacrylonitrile, polyacetal, ionomers, and polyesters, alkyd resins, phenolic resins, urea resins, benzoguanamine resins, melamine resins, xylene resins, silicone resins, epoxy resins, and diallyl phthalate resins. In the resin composition of the present invention, it is preferable to use conductive particles in which metal particles such as gold, silver, copper, nickel, palladium, and solder are used as core material particles, and one or more metal films selected from gold, silver, copper, nickel, palladium, and solder are formed on the surface of the metal particles, since the particle surface is uniformly and densely coated with a metal film, has oxidation resistance, and has low resistance during connection. It is even more preferable to use conductive particles in which nickel is used as the core material particle, and the metal film is formed on the surface of the nickel by an electroless plating method. The metal film may also include alloys (for example, nickel-phosphorus alloys and nickel-boron alloys).

[0039] When conductive particles with a metal film formed on the surface of core material particles are used as an electrical conductive agent, the average particle size of the core material particles is preferably 0.1 μm to 1000 μm, and particularly preferably 0.5 μm to 100 μm. If the average particle size of the core material particles is too small, conductivity may be difficult even with conductive particles that have a metal film formed on them, and if the average particle size of the core material particles is too large, a short circuit may occur. The average particle size of the core material particles is the value measured using the electrical resistance method.

[0040] Furthermore, the particle size distribution of core material particles measured by the method described above has a range. Generally, the range of particle size distribution of a powder is expressed by the coefficient of variation shown in the following formula (i): Coefficient of variation (%) = (Standard deviation / Average particle size) × 100 ... (i) A large coefficient of variation indicates a wide range of distribution, while a small coefficient of variation indicates a sharp particle size distribution. It is preferable to use core material particles with a coefficient of variation of 50% or less, preferably 30% or less, and particularly preferably 20% or less, as this increases the effective contribution to the connection between circuit components and circuit boards.

[0041] Furthermore, there are no particular restrictions on the shape of the core material particles. Generally, the core material particles may be in the form of powder or granules, but they may also be in other shapes, such as fibrous, hollow, plate-like, or needle-like, and may have numerous protrusions on the particle surface or be irregular in shape. Among these, spherical core material particles are particularly preferred because they have excellent packing properties when used as conductive particles.

[0042] Furthermore, while there are no particular limitations on other physical properties of the core material particles, in the case of core material particles made of resin material, the value of K, as defined by the following calculation formula (ii), must be 100 N / mm at 20°C. ２ ~100000N / mm ２ A material within the range of K (N / mm²) and with a recovery rate of 1% to 100% after 10% compression deformation at 20°C is preferred because it prevents damage to the electrodes when they are pressed together and allows for sufficient contact between the electrodes. ２ ) = (3 / √2) × F × S －３／２ ×R －１／２ ... (ii) [In formula (ii), F and S are the load value (N) and compression displacement (mm) at 10% compression deformation of the core material particles, respectively, as measured by a micro-compression testing machine (MCTM-500 manufactured by Shimadzu Corporation), and R is the radius (mm) of the core material particles as measured by a micro-compression testing machine (MCTM-500 manufactured by Shimadzu Corporation)]

[0043] Furthermore, conductive particles may be used in which the surface of the conductive particles has been treated with a hydrophobic agent as needed to improve the moisture resistance and corrosion resistance of the conductive particles. Examples of such hydrophobic agents include benzotriazole compounds, titanate coupling agents, higher fatty acids and their derivatives, phosphate esters and phosphite esters. These may be used alone or in combination of two or more as needed.

[0044] The resin composition of the present invention, obtained by mixing the metal oxide of the present invention, an epoxy resin, a latent curing agent, and conductive particles as an electrical conductor, becomes a conductive adhesive and is particularly useful as a connecting adhesive that can connect circuit components and circuit boards in a short time without impairing adhesion and connection reliability.

[0045] The conductive adhesive of the present invention comprises a resin composition containing the aforementioned conductive particles. The content of conductive particles is preferably 1 to 70% by mass in the conductive adhesive, and particularly preferably 5 to 30% by mass, from the viewpoint of adhesion and connection reliability.

[0046] The conductive adhesive of the present invention can be used in various forms, such as paste or sheet.

[0047] The conductive adhesive of the present invention enables highly reliable electrode connections in miniaturized IC chips, electronic components such as light-emitting diodes, and circuit boards.

[0048] Examples of adhesive structures in which members to be bonded are bonded together via the conductive adhesive of the present invention include RFID-related products such as IC cards and IC tags, in which an IC chip is bonded to a substrate having electrodes, and light-emitting electronic components in which a light-emitting diode is bonded to a substrate having electrodes.

[0049] A known method can be used to bond electronic components using the conductive adhesive of the present invention. For example, one method involves applying the conductive adhesive of the present invention to the surface of a substrate on which electrodes are formed, using a coating apparatus such as a slit coater, roll coater, spin coater, screen printing method, metal mask printing method, dispenser, or jet dispenser, to a film thickness of 0.1 to 100 μm, and then placing the electronic components on the substrate such that a portion of the electronic components is positioned above the electrodes, and then heating and pressurizing the resulting laminate.

[0050] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The characteristics in the examples were measured by the following methods. (1) Exothermic peak temperature Differential scanning calorimetry (METTLER TOLEDO, STAR SYSTEM) was used to measure the change in heat quantity from 25°C to 200°C at a heating rate of 5°C / min under a nitrogen atmosphere, and the temperature of the exothermic peak was determined. (2) Pot life Viscometer (HAAKE, MARS60) was used to measure the time it took for the viscosity of the resin composition to double under normal temperature (25°C) conditions and was evaluated according to the following criteria. ○: 3 days or more until viscosity doubles ×: Less than 3 days until viscosity doubles (3) Compressibility The compressibility of the metal oxide was calculated from the following formula (A). Compression ratio (%) = ((tap density - apparent density) / tap density) × 100 ... (A) Here, the apparent density and tap density were measured in accordance with the method in accordance with JIS K 5101-12-2:2004.

[0051] (Examples 1-3) The amounts of epoxy resin (manufactured by Daicel Corporation, Celoxide® 2021P), viscosity modifier (manufactured by Nippon Aerosil Co., Ltd., product name: Aerosil® 200), and specific surface area of ​​23.5 m² are shown in Table 1. ２ / g, compressibility 36% (apparent density 0.46 g / cm³) ３ Tap density 0.72 g / cm³ ３Titanium oxide (manufactured by Toho Titanium Co., Ltd., trade name: HT2321) was thoroughly mixed in a rotary-orbiting vacuum degassing stirrer to obtain a mixed liquid. Then, the amount of latent curing agent (manufactured by Sanshin Chemical Co., Ltd., trade name: SunAid (registered trademark SI-60L) shown in Table 1 was added to the obtained mixed liquid, and the mixture was further thoroughly mixed in a rotary-orbiting vacuum degassing stirrer to obtain a resin composition. The results of measuring the exothermic peak and pot life of the obtained resin composition are shown in Table 2.

[0052] (Examples 4-6) The amounts of epoxy resin (manufactured by Daicel Corporation, Celoxide® 2021P), viscosity modifier (manufactured by Nippon Aerosil Co., Ltd., product name: Aerosil® 200), and specific surface area of ​​12.5 m² were used as shown in Table 1. ２ / g, compressibility 40% (apparent density 0.15 g / cm³) ３ Tap density 0.25 g / cm³ ３ Titanium oxide (manufactured by Toho Titanium Co., Ltd., product name: FTL-100) was thoroughly mixed in a rotary-orbiting vacuum degassing agitator to obtain a mixed liquid. Then, the amount of latent curing agent (manufactured by Sanshin Chemical Co., Ltd., product name: Sun-Aid (registered trademark SI-60L) shown in Table 1 was added to the obtained mixed liquid, and the mixture was further thoroughly mixed in a rotary-orbiting vacuum degassing agitator to obtain a resin composition. The results of measuring the exothermic peak and pot life of the obtained resin composition are shown in Table 2.

[0053] (Example 7) The amounts of epoxy resin (manufactured by Mitsubishi Chemical Corporation, jER® 828EL), viscosity modifier (manufactured by Nippon Aerosil Co., Ltd., product name: Aerosil® 200), and specific surface area of ​​23.5 m² were used as shown in Table 1. ２ / g, compressibility 36% (apparent density 0.46 g / cm³) ３ Tap density 0.72 g / cm³ ３ Titanium oxide (manufactured by Toho Titanium Co., Ltd., trade name: HT2321) was thoroughly mixed in a rotary-orbiting vacuum degassing stirrer to obtain a mixed liquid. Then, the amount of latent curing agent (manufactured by Sanshin Chemical Co., Ltd., trade name: SunAid (registered trademark SI-60L) shown in Table 1 was added to the obtained mixed liquid, and the mixture was further thoroughly mixed in a rotary-orbiting vacuum degassing stirrer to obtain a resin composition. The results of measuring the exothermic peak and pot life of the obtained resin composition are shown in Table 2.

[0054] (Example 8) The amounts of epoxy resin (Daicel Corporation, Celoxide® 2021P and Mitsubishi Chemical Corporation, jER® 828EL), viscosity modifier (Nippon Aerosil Co., Ltd., product name: Aerosil® 200), and specific surface area of ​​23.5 m² were used. ２ / g, compressibility 36% (apparent density 0.46 g / cm³) ３ Tap density 0.72 g / cm³ ３ Titanium oxide (manufactured by Toho Titanium Co., Ltd., trade name: HT2321) was thoroughly mixed in a rotary-orbiting vacuum degassing stirrer to obtain a mixed liquid. Then, the amount of latent curing agent (manufactured by Sanshin Chemical Co., Ltd., trade name: SunAid (registered trademark SI-60L) shown in Table 1 was added to the obtained mixed liquid, and the mixture was further thoroughly mixed in a rotary-orbiting vacuum degassing stirrer to obtain a resin composition. The results of measuring the exothermic peak and pot life of the obtained resin composition are shown in Table 2.

[0055] (Example 9) The amounts of epoxy resin (manufactured by Daicel Corporation, Celoxide® 2021P), viscosity modifier (manufactured by Nippon Aerosil Co., Ltd., product name: Aerosil® 200), and specific surface area of ​​6.5 m² were used as shown in Table 1. ２ / g, compressibility 27% (apparent density 0.55 g / cm³) ３ Tap density 0.75 g / cm³ ３ Titanium oxide (manufactured by Toho Titanium Co., Ltd., product name: HT0514) was thoroughly mixed in a rotary-orbiting vacuum degassing stirrer to obtain a mixed liquid. Then, the amount of latent curing agent (manufactured by Sanshin Chemical Co., Ltd., product name: SunAid (registered trademark SI-60L) shown in Table 1 was added to the obtained mixed liquid, and the mixture was further thoroughly mixed in a rotary-orbiting vacuum degassing stirrer to obtain a resin composition. The results of measuring the exothermic peak and pot life of the obtained resin composition are shown in Table 2.

[0056] (Comparative Example 1) The amounts of epoxy resin (manufactured by Daicel Corporation, Celoxide® 2021P) and viscosity modifier (manufactured by Nippon Aerosil Co., Ltd., trade name: Aerosil® 200) shown in Table 1 were thoroughly mixed in a rotary-orbiting vacuum degassing stirrer to obtain a mixed liquid. Then, the amount of latent curing agent (manufactured by Sanshin Chemical Co., Ltd., trade name: Sun-Aid® SI-60L) shown in Table 1 was added to the obtained mixed liquid, and the mixture was further thoroughly mixed in a rotary-orbiting vacuum degassing stirrer to obtain a resin composition. The results of measuring the exothermic peak and pot life of the obtained resin composition are shown in Table 2.

[0057]

[0058]

[0059] The results in Table 2 show that the resin composition obtained in the example has a higher exothermic peak, suppressed curing reaction at room temperature (25°C), and a longer pot life compared to the resin composition obtained in the comparative example.

[0060] (Example 10) The same procedure as in Example 1 was carried out to obtain a conductive adhesive, except that 20 parts by mass of conductive particles (manufactured by Nippon Chemical Industrial Co., Ltd., product name: 6GNM5-NiS) were added.

[0061] (Example 11) The same procedure as in Example 4 was carried out to obtain a conductive adhesive, except that 20 parts by mass of conductive particles (manufactured by Nippon Chemical Industrial Co., Ltd., product name: 6GNM5-NiS) were added.

[0062] (Comparative Example 2) The same procedure as in Comparative Example 1 was performed except that 20 parts by mass of conductive particles (manufactured by Nippon Chemical Industrial Co., Ltd., product name: 6GNM5-NiS) were added to obtain a conductive adhesive.

[0063] <Evaluation> The following evaluation items were performed for Examples 10, 11 and Comparative Example 2. The evaluation results are shown in Table 3. <Pot Life> The time it took for the viscosity of the resin composition to double was measured at room temperature (25°C) using a rheometer (HAKEMARS, manufactured by ThermoFisher) and evaluated according to the following criteria: ○: Viscosity doubles in 3 days or more ×: Viscosity doubles in less than 3 days <Gel Time at 150°C> In accordance with the hot plate method of Method A of 7.1.5 of JIS-C2161:2010, 1 ml each of the resin composition or conductive adhesive obtained in the examples and comparative examples was placed on a hot plate at 150°C and the time (seconds) until gelation occurred while stirring was measured. The results are shown in Table 3. The resin compositions used were prepared within 3 hours.

[0064] <Adhesion> Conductive adhesives prepared in Examples 4-6 and Comparative Example 2 were applied by dispensing to a substrate (size: 2.5 cm long, 8 cm wide) on which aluminum wiring was formed on a PET film, covering the entire area of ​​the aluminum wiring, so that the cured thickness was 100 μm. An IC with gold bumps was then placed on top. Temperature: 190°C, 1 N / mm ２ An IC tag, which is an adhesive structure, was fabricated by connecting the substrate and the IC by curing the conductive adhesive by heating it for 2 seconds under pressure. The conductive adhesive used was prepared within 3 hours. The adhesion was evaluated by measuring the die shear strength of the fabricated IC tag. Die shear strength is the strength (N / mm²) required to peel the IC chip from the substrate. ２ The die shear strength was measured using a digital force gauge. The results are shown in Table 3. The die shear strength results in the table indicate the following: ○: 10 N / mm ２ More than ×: 10N / mm ２<Connection Reliability> The communication strength of the fabricated IC tag and the communication strength of the IC tag after a high-temperature, high-humidity test (85°C, 85RH, 168 hours) were measured separately. The pass rate (%) was calculated based on the difference between the former and the latter being 2 dBm or less. The communication strength was measured using the Tagformance® Pro system manufactured by Voyantic. The results are shown in Table 3. The connection reliability results in the table indicate the following: ○: 70% or more △: 30% or more and less than 70% ×: Less than 30%

[0065]

[0066] The results in Table 3 show that the conductive adhesives of Example 10 and Example 11 all exhibit superior properties in terms of pot life, gel time, adhesion, and connection reliability compared to the conductive adhesive of Comparative Example 2.

Claims

1. A resin composition containing an epoxy resin, a latent curing agent, and a metal oxide, wherein the compressibility of the metal oxide, as determined by the following formula (A), is 15% or more and 50% or less. Compressibility (%) = ((Tap density - Apparent density) / Tap density) × 100 ... (A) 2. The resin composition according to claim 1, wherein the metal of the metal oxide is Ti, Al, Mg, Zr, and Zn.

3. The resin composition according to claim 1, wherein the metal oxide is titanium oxide or aluminum oxide.

4. The apparent density of the metal oxide is 0.1 g / cm³. ３ 0.7g / cm or more ３ The following is true, and the tap density is 0.2 g / cm³. ３ 0.9g / cm or more ３ The resin composition according to claim 1, wherein the following applies:

5. The specific surface area of ​​the metal oxide is 0.5 m². ２ / g or more 100m ２ The resin composition according to claim 1, wherein the amount is less than or equal to / g.

6. The resin composition according to claim 1, wherein the latent curing agent is at least one selected from the group consisting of aromatic sulfonium salts, aromatic diazonium salts, aromatic iodonium salts, and aromatic selenium salts.

7. The resin composition according to claim 1, wherein the epoxy resin is at least one selected from the group consisting of alicyclic epoxy resins, polyhydric phenol compounds, and glycidyl-type epoxy resins.

8. The resin composition according to any one of claims 1 to 7, further comprising conductive particles.

9. The resin composition according to claim 8, wherein the conductive particles are metal particles selected from the group consisting of nickel, gold, silver, palladium, copper, and solder.

10. The resin composition according to claim 8, wherein the conductive particles are particles on which a metal film has been formed on the surface of core material particles by an electroless plating method.

11. The resin composition according to claim 10, wherein the metal film comprises at least one selected from the group consisting of nickel, gold, silver, palladium, copper, and solder.

12. A conductive adhesive comprising the resin composition described in claim 8.

13. An adhesive structure in which members to be bonded are bonded together via the conductive adhesive of claim 12.

14. An electronic component using the conductive adhesive of claim 12.

15. The electronic component according to claim 14, wherein the electronic component is selected from the group consisting of IC cards, IC tags, and light-emitting electronic components.

Images