Curable resin composition, adhesive, sealing material, cured product, semiconductor apparatus, and electronic device

Abstract

Provided are: a curable resin composition which can be cured at low temperatures, from which a cured product having a low Tg can be obtained, and which has excellent conformability to an adherend; an adhesive; a sealing material; a cured product having a low Tg; a semiconductor apparatus including the cured product; and an electronic device including the cured product. The curable resin composition comprises (A) a cationic curable resin, (B) an acid generator including an iodonium salt, and (C) a peroxydicarbonate-type organic peroxide. The component (A) includes at least one selected from the group consisting of (A1) an epoxy resin having a ring skeleton in a molecule, and (A2) an oxetane resin.

Description

Curable resin composition, adhesive, sealing material, cured product, semiconductor device, and electronic device

[0001] The present invention relates to a curable resin composition, an adhesive, an encapsulant, a cured product, a semiconductor device, and an electronic device.

[0002] Curable resin compositions containing cationically polymerizable compounds are used as adhesives in the field of electronic devices because the cured products thereof have excellent properties such as adhesiveness, electrical insulation, chemical resistance, and mechanical strength.

[0003] For example, Patent Document 1 describes that in a thermally cationically polymerizable composition that can be used in the field of adhesives, etc., insufficiently cured components volatilize as outgassing during a heat resistance test, etc., and contaminate the surroundings. Patent Document 1 discloses a thermally cationically polymerizable composition that can maintain a high glass transition temperature (Tg) of more than 100°C by adjusting the amount of a thermally cationically polymerizable initiator added to the composition in order to reduce the amount of outgassing.

[0004] Japanese Patent Application Laid-Open No. 2022-105415

[0005] When the adherends to be bonded are components of precision equipment such as camera modules and sensor modules, low-temperature curing is required, and an adhesive that can produce a cured product with a low Tg is desired. Furthermore, when different materials are often bonded, such as in camera modules and sensor modules, the adhesive may be required to have the ability to follow the expansion and contraction of the adherend in order to mitigate expansion and contraction due to differences in the linear expansion coefficients of the different materials.

[0006] Therefore, an object of the present invention is to provide a curable resin composition, an adhesive, and an encapsulant that can be cured by heating at a low temperature, for example, of 100°C or less, preferably 80°C or less; a cured product obtained by curing these, which has a low Tg and excellent conformability to an adherend; and a semiconductor device and an electronic device that include the cured product.

[0007] The means for solving the above problems are as follows, and the present invention includes the following aspects.

[0008] [1] A curable resin composition comprising (A) a cationic curable resin, (B) an acid generator containing an iodonium salt, and (C) a peroxydicarbonate-type organic peroxide. [2] The curable resin composition according to [1], wherein the component (A) comprises at least one selected from the group consisting of (A1) an epoxy resin having a ring skeleton in the molecule, and (A2) an oxetane resin. [3] The curable resin composition according to [2], wherein the component (A1) has an aromatic ring skeleton. [4] The curable resin composition according to any one of [1] to [3], wherein the one-hour half-life temperature of the component (C) is 50°C to 80°C. [5] The curable resin composition according to any one of [1] to [4], wherein the iodonium salt contained in the component (B) is an iodonium salt compound represented by the following formula (1): (In the formula (1), Ar １ and Ar ２ are each independently a substituted or unsubstituted aryl group; Z － is an anion.) [6] Z in the formula (1) － But BF ４ － , SbF ６ -, AsF ６ － , B(C ６ F ５ ) ４ － , or Ga(C ６ F ５ ) ４ － , C(CF ３ SO ２ ) ３ － , or [P(R ３ ) ａ F ６－ａ ] － , [C(R ３ SO ２ ) ３ ] － , or [N(R ３ SO ２ ) ２ ] － (In the formula, R ３are each independently an alkyl group in which at least a portion of the hydrogen atoms is substituted with a fluorine atom, a is an integer of 0 to 5, and when a is an integer of 2 or more, a plurality of R ３ may be the same or different. ) is the curable resin composition according to [5] above. [7] The curable resin composition according to [2] or [3] above, wherein the component (A1) contains an epoxy resin having an epoxy group equivalent of 100 g / eq to 1000 g / eq. [8] An adhesive or encapsulant comprising the curable resin composition according to any one of [1] to [7] above. [9] A cured product obtained by curing the curable resin composition according to any one of [1] to [7] above or the adhesive or encapsulant according to [8] above.

[10] The cured product according to [9] above, wherein the glass transition temperature (Tg) of the cured product is 0°C to 100°C.

[11] A semiconductor device comprising the cured product according to [9] or

[10] above.

[12] An electronic device comprising the cured product according to [9] or

[10] above.

[0009] According to the present invention, it is possible to provide a curable resin composition, an adhesive, an encapsulant, which can be cured by heating at a low temperature of 100°C or less, preferably 80°C or less, a cured product obtained by curing the composition or the adhesive and having a low Tg and excellent conformability to an adherend, and a semiconductor device and an electronic device including the cured product.

[0010] FIG. 1 is a diagram showing a method for manufacturing a test piece for testing a thin-film cured product.

[0011] Hereinafter, the curable resin composition, adhesive, encapsulant, cured product obtained by curing these, and semiconductor device and electronic device including the cured product according to the present disclosure will be described based on embodiments. However, the embodiments shown below are examples for embodying the technical idea of ​​the present invention, and the present invention is not limited to the curable resin composition, adhesive, encapsulant, cured product, semiconductor device, and electronic device described below. In this specification, following the convention in the field of synthetic resins, a name including the term "resin," which usually refers to a polymer (particularly a synthetic polymer), may be used for a component constituting a curable resin composition before curing, even though the component is not a polymer.

[0012] Resin Composition The curable resin composition according to the first embodiment of the present invention is a curable resin composition comprising: (A) a cationically curable resin (hereinafter also referred to as “component (A)”); (B) an acid generator containing an iodonium salt (hereinafter also referred to as “component (B)”); and (C) a peroxydicarbonate-type organic peroxide (hereinafter also referred to as “component (C)”).

[0013] A curable resin composition that uses an iodonium salt-based cationic polymerization initiator and an organic peroxide as a thermal radical polymerization initiator to obtain a cured product through a radical redox reaction can be cured at a relatively low temperature, and a cured product with almost the same physical properties can be obtained whether the composition is cured by heat or by irradiation with heat and ultraviolet light.

[0014] However, radicals generated from organic peroxides are susceptible to curing inhibition by oxygen. Radicals generated from organic peroxides undergo hydrogen abstraction reactions to generate stable alkyl radicals, such as tertiary radicals. Stable alkyl radicals react with oxygen to generate relatively stable peroxide radicals. Because peroxide radicals are stable, they hardly react with iodonium salt-based compounds. Therefore, radical redox reactions are easily inhibited. The thinner the cured product, the more likely it is to be inhibited by oxygen. This is thought to be because the thinner the cured product, the greater the surface area exposed to air relative to its volume. Oxygen-induced curing inhibition raises concerns that insufficient curing areas may result in insufficient adhesion, reduced adhesive strength, and increased susceptibility to deterioration. Poor adhesion due to oxygen-induced curing inhibition has been observed in both resin compositions that produce cured products with high Tg and those that produce cured products with low Tg. However, oxygen-induced curing inhibition is particularly likely to occur when the Tg is low. In this specification, a cured product having a low Tg refers to a cured product having a Tg of, for example, 120°C or less, and may be a cured product having a Tg of 118°C or less, and is preferably a cured product having a Tg of 0 to 100°C. If the product is insufficiently cured in a thin film, outgassing may occur, potentially contaminating the surroundings. On the other hand, if the product is sufficiently cured in a thin film, outgassing can be reduced, and the surrounding contamination can be alleviated. Examples of thin film cured products include membrane-, layer-, or film-like cured products having a thickness of 100 μm or less.

[0015] The curable resin composition contains a peroxydicarbonate-type organic peroxide as component (C). The carbonate radicals generated from component (C) rapidly abstract hydrogen from other compounds contained in the curable resin composition, generating unstable alkyl radicals such as primary radicals. Because unstable alkyl radicals are prone to radical redox reactions, the reaction of unstable alkyl radicals is believed to be faster than the reaction rate of curing inhibition by oxygen. Therefore, the carbonate radicals generated from component (C) are believed to be able to rapidly advance the curing reaction of the cationic curable resin. Furthermore, because the hydrogen abstraction reaction of carbonate radicals is faster than that of alkoxy radicals, the instantaneous radical concentration in the curable resin composition system is believed to be higher than that of organic peroxides other than component (C). Therefore, even if the carbonate radicals generated from component (C) are affected by oxygen inhibition, many radicals remain uninhibited and can react with component (B), rapidly advancing the curing reaction of the cationic curable resin. Even when producing a thin, curable resin composition, the polymerization reaction proceeds more quickly than oxygen can inhibit curing, even when producing a thin, cured product. Therefore, the composition can be cured at low temperatures, for example, 100°C or less, preferably 90°C or less, more preferably 85°C or less, and even more preferably 80°C or less, resulting in a cured product with a low Tg. Furthermore, even when producing a thin, cured product with a thickness of 100 μm or less, preferably 0.5 μm to 100 μm, curing inhibition by oxygen is suppressed, and the composition can be cured at low temperatures, for example, 100°C or less, preferably 80°C or less, resulting in a cured product with a low Tg. A cured product with a thickness of 0.5 μm to 100 μm is called a thin-film cured product. The thickness of the cured product may be 90 μm or less, 80 μm or less, 70 μm or less, or 1 μm or more.

[0016] When a curable resin composition is used as an adhesive for bonding different materials, such as in a camera module or a sensor module, the adhesive may be required to have the ability to follow the expansion and contraction of the adherend in order to mitigate expansion and contraction due to differences in the linear expansion coefficients of the different materials. To obtain a cured product with this ability, the curable resin composition may contain a resin with a large functional group equivalent as a cationic curable resin. Here, functional group equivalent refers to the proportion of reactive functional groups in one molecule. For example, in the case of an epoxy resin, this refers to the epoxy group equivalent, which is the molecular weight per equivalent of an epoxy group in the compound. For example, in the case of an oxetane resin, this refers to the oxetane group equivalent, which is the molecular weight per equivalent of an oxetane group in the compound. The epoxy group equivalent or oxetane group equivalent can be measured in accordance with JIS K7236:2001 (corresponding to ISO3001:1999). The functional group equivalent number, such as the epoxy group equivalent number or the oxetane group equivalent number, refers to the number of functional groups (equivalent number) per compound mass (charge amount). Resins or compounds with a high functional group equivalent in a curable resin composition have a slower reaction rate than resins or compounds with a low functional group equivalent. Therefore, when a resin or compound with a high functional group equivalent is included as a cationic curable resin, the cationic reactivity may be insufficient, resulting in insufficient curing, which may result in poor adhesion. Curable resin compositions containing resins or compounds with a high functional group equivalent have a low storage modulus (E'), a low Tg, and can produce cured products with the ability to follow the expansion and contraction of the adherend.

[0017] The curable resin composition of the present invention contains (B) an acid generator containing an iodonium salt and (C) a peroxydicarbonate-type organic peroxide, and therefore is less likely to suffer from poor curing even when a resin with a large functional group equivalent is used as the cationic curable resin. Peroxydicarbonate-type organic peroxides have a relatively low half-life temperature and are excellent in reactivity at low temperatures. It is believed that the reaction rate between the generated radicals and component (B) derived from component (C) is faster than the reaction rate of curing inhibition by oxygen. Therefore, a radical redox reaction is likely to occur, and an acid (cation: H ＋For example, even when heated at a low temperature of 100°C or less, preferably 80°C or less, the curing reaction of the cationically curable resin can be rapidly advanced, partial curing defects can be suppressed, and a cured product having a low Tg can be obtained.

[0018] In order to obtain a cured product having conformability, it is considered that the curable resin composition contains, for example, a resin having a linear alkyl group or alkylene group with a large number of carbon atoms as a cationically curable resin. Resins having a linear long-chain alkyl group or alkylene group with a large number of carbon atoms tend to have lower cationic reactivity than resins having a linear alkyl group or alkylene group with a small number of carbon atoms.

[0019] The curable resin composition of the present invention contains (B) an acid generator containing an iodonium salt and (C) a peroxydicarbonate-type organic peroxide, and therefore can be cured even when a resin with a large functional group equivalent is used as the cationic curable resin. For example, by heating at a low temperature of 100°C or less, preferably 80°C or less, even a cationic curable resin with a large functional group equivalent exhibits cationic reactivity, the curing reaction proceeds rapidly, and a cured product with good conformability can be obtained.

[0020] Furthermore, a curable resin composition containing a resin having a ring structure such as an aromatic ring in the molecule can produce a cured product that can follow the expansion and contraction of an adherend. However, resins having a ring structure such as an aromatic ring in the molecule tend to have low cationic reactivity.

[0021] The curable resin composition of the present invention contains (B) an acid generator containing an iodonium salt and (C) a peroxydicarbonate-type organic peroxide. Therefore, even when a resin having a ring skeleton in the molecule is used as the cationically curable resin, radicals are efficiently generated from the peroxydicarbonate-type organic peroxide, and a radical redox reaction easily occurs. Therefore, by heating at a low temperature of, for example, 100°C or less, preferably 80°C or less, the cationically curable resin having an aromatic ring in the molecule can be rapidly cured, and a cured product having excellent conformability to the adherend can be obtained.

[0022] Component (A): Cationic Curable Resin The cationic curable resin of component (A) refers to a resin having one or more cationic polymerizable groups in the molecule, and examples of the cationic polymerizable group include an epoxy group, an oxetanyl group, and a vinyl ether group. Examples of the cationic curable resin include an epoxy resin, an oxetane resin, a polystyrene-based compound, and a vinyl ether compound. The cationic curable resin of component (A) is cured by heating at a low temperature of 100°C or less, preferably 80°C or less, to obtain a cured product having a low Tg and excellent conformability to the adherend, and therefore preferably has a molecular weight of 100 to 800, and may also be 110 to 780.

[0023] The cationically curable resin of component (A) preferably contains at least one selected from the group consisting of (A1) an epoxy resin having a ring skeleton in the molecule (hereinafter also referred to as "component (A1)"), and (A2) an oxetane resin (hereinafter also referred to as "component (A2)"). By including in component (A) at least one selected from the group consisting of an epoxy resin having the ring skeleton of component (A1) in the molecule, and (A2) an oxetane resin, it is possible to obtain a cured product having a low Tg, a low elastic modulus, and excellent followability. Component (A) may contain component (A1) alone, or may contain both component (A1) and component (A2).

[0024] Examples of the epoxy resin include an aliphatic epoxy resin and an epoxy resin having an (A1) ring skeleton in the molecule. The epoxy resin preferably contains an epoxy resin having an (A1) ring skeleton in the molecule. Examples of the ring skeleton include an alicyclic skeleton, an aromatic ring skeleton, a heteroaromatic ring skeleton, and a heterocyclic skeleton. The epoxy resin of component (A1) preferably contains at least one selected from the group consisting of epoxy resins having an aromatic ring skeleton in the molecule and epoxy resins having an alicyclic skeleton in the molecule, and more preferably contains an epoxy resin having an aromatic ring skeleton.

[0025] Epoxy resins having an aromatic ring skeleton include polyfunctional epoxy resins, specifically bisphenol A type epoxy resins (EPICLON (registered trademark) 850, 850-S, EXA-850CRP, EXA-8067, etc., manufactured by DIC Corporation), special epoxy resins in which a polyalkylene oxide structure is added to a bisphenol A skeleton (AER9000 manufactured by Asahi Kasei Corporation, EP-4000S, EP-4003S, EP-4010S, manufactured by ADEKA Corporation), bisphenol F type epoxy resins (EPICRO manufactured by DIC Corporation), and the like. N (registered trademark) 830-S, EXA-830LVP, etc.), bisphenol AD ​​type epoxy resin, bisphenol S type epoxy resin, naphthalene type epoxy resin (EPICLON (registered trademark), HP-4032D, HP-720H, etc., manufactured by DIC Corporation), phenol novolac type epoxy resin (EPICLON (registered trademark), N-740, N-770, etc., manufactured by DIC Corporation), cresol volac type epoxy resin (EPICLON (registered trademark), N-660, N-670, N-655-EXP-S, etc., manufactured by DIC Corporation). Specific examples of the polyfunctional epoxy compound contained in the polyfunctional epoxy resin include glycidyl ethers of tetra(hydrophenyl)alkanes, glycidyl ethers of tetrahydroxybenzophenone, and epoxidized polyvinylphenol. Specific examples of compounds contained in monofunctional epoxy resins include p-tert-butylphenyl glycidyl ether (ADEKA GLYCIROL (registered trademark), ED-509E, ED-509S, etc., manufactured by ADEKA CORPORATION). Bisphenol A epoxy resins contain aromatic rings in the molecule, which tend to have low reactivity and a high Tg, which can impair conformability to the adherend. For this reason, from the viewpoint of Tg, it is preferable that the amount of bisphenol A epoxy resins having an epoxy group equivalent of 200 g / eq or less is 20% by mass or less when the total amount of component (A) is taken as 100% by mass.

[0026] The epoxy resin having an alicyclic skeleton may be any epoxy resin having an alicyclic skeleton in one molecule, and may include a cycloalkylene oxide compound in which an epoxy group is formed by two carbon atoms and one oxygen atom forming an alicyclic structure. The epoxy resin having an alicyclic skeleton may also include an epoxy compound having an alicyclic skeleton. Examples of the epoxy compound having an alicyclic skeleton include cyclohexane-based, cyclohexyl methyl ester-based, cyclohexyl methyl ether-based, spiro-based, and tricyclodecane-based epoxy compounds. Specific examples of epoxy resins having an alicyclic skeleton include 3',4'-epoxycyclomethyl 3,4-epoxycyclohexane carboxylate (Celloxide (registered trademark) 2021P manufactured by Daicel Corporation, etc.), (3,3',4,4'-diepoxy)bicyclohexyl (Celloxide (registered trademark) 8010 manufactured by Daicel Corporation, etc.), 1,2:8,9-diepoxylimonene, 1,2-epoxy-4-vinylcyclohexane, and 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol (EHPE3150 manufactured by Daicel Corporation, etc.).

[0027] Examples of aliphatic epoxy resins include polyglycidyl ethers of polyhydric alcohols or their alkylene oxide adducts. Specific examples of aliphatic epoxy compounds contained in aliphatic epoxy resins include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether (such as Epolite 100MF manufactured by Kyoeisha Chemical Co., Ltd.), and polyethylene glycol diglycidyl ether. Examples of aliphatic cyclic epoxy resins include hydrogenated bisphenol A diglycidyl ether (such as jER YX8000 manufactured by Mitsubishi Chemical Corporation).

[0028] Specific examples of vinyl ether compounds include hydroxybutyl vinyl ether, vinyl ether of 1,4-cyclohexanedimethanol, triethylene glycol divinyl ether, dodecyl vinyl ether, and cyclohexyl vinyl ether.

[0029] When component (A) contains an epoxy resin, the epoxy group equivalent of the epoxy resin is preferably 100 g / eq to 1000 g / eq. When component (A) contains an epoxy resin having the ring skeleton of component (A1) in the molecule, component (A1) preferably has an epoxy group equivalent of 100 g / eq to 1000 g / eq. When the epoxy group equivalent of the epoxy resin contained in component (A) is 100 g / eq to 1000 g / eq, a cured product having a low Tg can be obtained when cured by heating at a low temperature, for example, 100°C or less, preferably 80°C or less. When component (A) contains an epoxy resin, the epoxy group equivalent of the epoxy resin may be 800 g / eq or less, 600 g / eq or less, 500 g / eq or less, 400 g / eq or less, 120 g / eq or more, 130 g / eq or more, 150 g / eq or more, 180 g / eq or more, or 200 g / eq or more. Epoxy resins with an epoxy group equivalent of 200 g / eq or less tend to have a low epoxy group equivalent number and a high Tg, which may impair adherend conformability. Therefore, when an epoxy resin with an epoxy group equivalent of 200 g / eq or less is contained, the epoxy resin with an epoxy group equivalent of 200 g / eq or less is preferably 20% by mass or less, 18% by mass or less, 0% by mass or less, 1% by mass or more, or 3% by mass or more, based on the total amount of component (A) being 100% by mass. From the viewpoint of obtaining a cured product with a low Tg, the epoxy resin having an epoxy group equivalent of more than 200 g / eq is preferably 10% by mass or more, more preferably 20% by mass, even more preferably 30% by mass, and particularly preferably 40% by mass or more, when the total amount of component (A) is taken as 100% by mass. Note that, from the viewpoint of conformability to the adherend, special epoxy resins in which a polyalkylene oxide structure is added to a bisphenol A skeleton are particularly preferred, and the blend amount thereof is preferably 10% by mass or more, more preferably 20% by mass or more, when the total amount of component (A) is taken as 100% by mass.

[0030] Although the polymerization initiation reaction of the oxetane resin of component (A2) is slower than that of the epoxy resin, it polymerizes rapidly once the initiation species for polymerization reaches a certain concentration or higher, and therefore a cured product can be obtained at a low temperature in a short reaction time. Specific examples of the oxetane resin include 3-ethyl-3-hydroxymethyloxetane (oxetane alcohol) (OXT-101 manufactured by Toagosei Co., Ltd., etc.), 2-ethylhexyloxetane (OXT-212 manufactured by Toagosei Co., Ltd., etc.), xylylene bisoxetane (OXT-121 manufactured by Toagosei Co., Ltd., etc.), 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane (OXT-221 manufactured by Toagosei Co., Ltd., etc.), oxetanyl silsesquioxetane (OXT-191 manufactured by Toagosei Co., Ltd., etc.), phenol novolac oxetane (PHOX manufactured by Toagosei Co., Ltd., etc.), and 3-ethyl-3-phenoxymethyloxetane (OXT-211 manufactured by Toagosei Co., Ltd., etc.).

[0031] When component (A) contains the oxetane resin of component (A2), the oxetane group equivalent of the oxetane resin is preferably 100 g / eq to 500 g / eq, and may be 110 g / eq to 300 g / eq. When component (A) contains the oxetane resin of component (A2), if the oxetane group equivalent of component (A2) is 100 g / eq to 500 g / eq, a cured product having a low Tg can be obtained when cured by heating at a low temperature, for example, 100°C or less, preferably 80°C or less. When component (A) contains the oxetane resin of component (A2), the oxetane group equivalent of the oxetane resin may be 250 g / eq or less.

[0032] Component (B): Acid Generator Containing Iodonium Salt The iodonium salt contained in the acid generator of component (B) is preferably an iodonium compound represented by the following formula (1). (In the formula (1), Ar １ and Ar ２ are each independently a substituted or unsubstituted aryl group; Z － is an anion.)

[0033] The aryl group represents an aromatic hydrocarbon group having 6 to 18 carbon atoms, and examples thereof include a phenyl group, a naphthyl group, and an anthracenyl group. １ and Ar ２ are each independently preferably a phenyl group or a naphthyl group. The aryl group may be unsubstituted or substituted with one or more optional substituents. Examples of the substituent include a linear or branched alkyl group having 1 to 18 carbon atoms, a linear or branched alkoxy group having 1 to 18 carbon atoms, a linear or branched acyloxy group having 2 to 18 carbon atoms, a halogen atom, a cyano group, a nitro group, and a hydroxyl group.

[0034] The anion may be a monovalent counter anion, and is preferably a non-antimony anion. － The anion represented by BF ４ － , SbF ６ -, AsF ６ － , B(C ６ F ５ ) ４ － , or Ga(C ６ F ５ ) ４ － , C(CF ３ SO ２ ) ３ － , or [P(R ３ ) ａ F ６－ａ ] － , [C(R ３ SO ２ ) ３ ] － , or [N(R ３ SO ２ ) ２ ] － (In the formula, R ３ are each independently an alkyl group in which at least a portion of the hydrogen atoms is substituted with a fluorine atom, a is an integer of 0 to 5, and when a is an integer of 2 or more, a plurality of R ３ In formula (1), Z may be the same or different.－ It is preferable that the nucleophilicity of the anion represented by the formula (I) is relatively low. When the nucleophilicity of the anion contained in the iodonium salt is low, the rate of the propagation reaction of the cationically curable resin increases, and a cured product can be obtained by heating at a low temperature of, for example, 100°C or less, preferably 80°C or less, for a short time.

[0035] Specific examples of component (B) include diphenyliodonium hexafluoroarsenate, di(4-chlorophenyl)iodonium hexafluoroarsenate, di(4-bromophenyl)iodonium hexafluoroarsenate, phenyl(4-methoxyphenyl)iodonium hexafluoroarsenate, 4-methylphenyl-4-(1-methylethyl)phenyliodonium hexafluorophosphate, 4-methylphenyl-4-(1-methylethyl)phenyliodonium tri(pentafluoroethyl)trifluorophosphate (e.g., IK-1 manufactured by San-Apro Co., Ltd.), 4-methylphenyl-4-(1-methylethyl)phenyliodonium tetrakis(pentafluorophenyl)borate, 4-methylphenyl-4-(2-methylpropyl)phenyliodonium hexafluorophosphate (e.g., IRGACURE (registered trademark) 250 manufactured by BASF), bis(C １０～１４ Examples of iodonium salts include 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate (e.g., Bluesil (registered trademark) PI2074 manufactured by ELKEM SILICONES). Commercially available iodonium salts can be used, for example, as cationic initiators or as iodonium salts contained in acid generators.

[0036] Component (C): Peroxydicarbonate-type organic peroxide The peroxydicarbonate-type organic peroxide of component (C) is a radical source. Even if the carbonate radicals generated from component (C) are affected by oxygen inhibition as described above, many radicals remain uninhibited and can react with component (B), allowing the curing reaction of the cationic curable resin to proceed quickly. Organic peroxides other than peroxydicarbonate-type, such as alkyl peroxy ester-type, are less active than peroxydicarbonate-type organic peroxides. Therefore, the reaction rate at which alkyl radicals are generated is slow, and electrons are less likely to transfer to the acid generator containing an iodonium salt, making the iodonium salt less likely to decompose. As a result, the acid (cation: H ＋ ) is hardly produced, and therefore, it is considered that the polymerization reaction is hardly progressed. It is preferable that the curable resin composition does not contain a thermal cationic polymerization initiator. By containing component (B) and component (C), the curable resin composition can promote the polymerization reaction by heating at a low temperature of 100°C or less, preferably 80°C or less, and also taking into consideration environmental aspects such as reducing PFAS (meaning organic fluorine compounds), it is preferable that the curable resin composition does not contain a thermal cationic polymerization initiator.

[0037] The peroxydicarbonate-type organic peroxide of component (C) has a structure represented by —O—C(═O)—O—O—C(═O)—O—. It is a radical source and generates carbonate radicals without decarboxylation. The peroxydicarbonate-type organic peroxide of component (C) preferably has a one-hour half-life temperature of 50°C to 80°C, but may also be 55°C to 75°C, and is preferably 55°C to 70°C. When the peroxydicarbonate-type organic peroxide of component (C) has a one-hour half-life temperature of 50°C to 80°C, it generates radicals by heating at a low temperature of, for example, 100°C or less, preferably 80°C or less, and reductively decomposes the iodonium salt. Even when a thin-film cured product having a thickness of, for example, 100 μm or less is obtained, curing inhibition by oxygen can be suppressed and the polymerization reaction of the cationic curable resin can be promoted. The peroxydicarbonate-type organic peroxide of component (C) preferably has a molecular weight of 180 to 1000, but may also be 200 to 800, or 220 to 700. When the peroxydicarbonate-type organic peroxide of component (C) has a molecular weight of 180 to 1000, the polymerization reaction can be carried out by heating at a low temperature, for example, of 100°C or less, preferably 80°C or less.

[0038] The peroxydicarbonate-type organic peroxide of component (C) preferably has a self-accelerating decomposition temperature (SADT) of greater than 10°C (>10°C), more preferably 12°C or higher (≧12°C), and even more preferably 15°C or higher (≧15°C). The peroxydicarbonate-type organic peroxide of component (C) preferably has a self-accelerating decomposition temperature (SADT) of 50°C or lower (≦50°C), or may be 48°C or lower (≦48°C), and more preferably 45°C or lower (≦45°C). A curable resin composition containing a peroxydicarbonate-type organic peroxide having a SADT of greater than 10°C but not higher than 50°C has good storage stability, and a cured product having a low Tg can be obtained by heating at a low temperature, for example, 100°C or lower, preferably 80°C or lower. The self-accelerating decomposition temperature (SADT) refers to the lowest temperature at which heat generation or self-accelerating decomposition of 6°C or more occurs within seven days when the organic peroxide is contained in a certain volume of container. The self-accelerating decomposition temperature of an organic peroxide indicates the temperature at which self-accelerating decomposition occurs. Test methods for the SADT include the American SADT test, the adiabatic storage test, the isothermal storage test, and the heat storage storage test, and any of these test methods may be used to measure the value. Furthermore, when a commercially available product described below is used as the peroxydicarbonate-type organic peroxide of component (C), the SADT may be a catalog value. From the viewpoint of the pot life at room temperature, it is preferable that component (C) be in the form of a solid (powder) rather than a liquid at room temperature (about 20°C to about 25°C).

[0039] Examples of the peroxydicarbonate-type organic peroxide of component (C) include di(secondary butyl)peroxydicarbonate (e.g., Luperox 225 manufactured by Arkema Yoshitomi Co., Ltd.), dicetyl peroxydicarbonate (e.g., Perkadox 24L manufactured by Nouryon), di(4-tert-butylcyclohexyl)peroxydicarbonate (e.g., Peroyl TCP manufactured by NOF Corporation), ditridecyl peroxydicarbonate (manufactured by Alfa Chemistry), and distearyl peroxydicarbonate (manufactured by SAGECHEM LIMITED).

[0040] The curable resin composition may contain at least one selected from the group consisting of a (D) photosensitizer, a (E) photoradical generator, and a (F) filler (hereinafter also referred to as "component (D)," "component (E)," and "component (F)," respectively). The curable resin composition may further contain at least one selected from the group consisting of a (G) coupling agent, a (H) ion trapping agent, and a (I) colorant such as a pigment (hereinafter also referred to as "component (G)," "component (H)," and "component (I)," respectively). At least one component selected from the group consisting of a (G) coupling agent, a (H) ion trapping agent, and a (I) colorant may be included as an optional component.

[0041] (D) Photosensitizer The photosensitizer is a component that increases the sensitivity of the iodonium salt to light. Examples of photosensitizers include thioxanthone derivatives, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, and photoreducible dyes, with thioxanthone derivatives being preferred. Specific examples of thioxanthone derivatives include isopropylthioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone, and thioxanthone ammonium salt, with 2,4-diethylthioxanthone being preferred.

[0042] (E) Photoradical Generator The photoradical generator, together with the peroxydicarbonate-type organic peroxide of component (C), is a radical source that generates radicals upon irradiation with light, reductively decomposes the iodonium salt, and converts it into an acid (cation: H ＋ ), which accelerates the polymerization reaction. The curable resin composition of the present invention does not need to contain (E) a photoradical generator because it contains the peroxydicarbonate-type organic peroxide of component (C). When the curable resin composition contains (E) a photoradical generator, it generates alkyl radicals by light, reductively decomposes the iodonium salt, and also generates an acid (cation: H ＋Examples of the photoradical generator include 1-hydroxycyclohexyl phenyl ketone (e.g., Omnirad (registered trademark) 184 manufactured by IGM Resins), 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one.

[0043] (F) Filler The filler is a component for improving the fluidity, injectability, coatability, adhesion, etc. of the curable resin composition. When the curable resin composition contains a filler, even when the composition is cured into a thin film having a thickness of 100 μm or less, preferably 50 μm or less, or when the composition is cured by heating at a low temperature, for example, 100° C. or less, preferably 80° C. or less, a thin film-like cured product having good curability and a low Tg can be obtained. Examples of the filler include known inorganic fillers or organic fillers. One type of filler may be used, or two or more types may be used in combination. The filler is preferably a powder or particle.

[0044] Examples of inorganic fillers include calcium carbonate, magnesium carbonate, barium sulfate, magnesium sulfate, aluminum silicate, titanium oxide, alumina, zinc oxide, silicon dioxide (precipitated silica, fumed silica, etc.), kaolin, talc, glass beads, sericite activated clay, aluminum hydroxide, asbestos powder, copper oxide, copper hydroxide, iron oxide, lead oxide, magnesium oxide, tin oxide, carbon, mica, smectite, carbon black, bentonite, aluminum nitride, and silicon nitride. Fillers may be added as thixotropic agents, and when a filler is added as a thixotropic agent, fumed silica is preferred. Fumed silica is not surface-treated. Examples of inorganic surface treatment agents for thixotropy-imparting agents include monoalkyltrialkoxysilane, dimethyldichlorosilane, polydimethylsiloxane, and hexamethyldisilazane. Commercially available surface-treated or untreated fumed silica can be used. From the viewpoint of adhesion to the adherend, the inorganic filler is preferably silicon dioxide, glass beads, or talc, with silicon dioxide being more preferred from the viewpoint of improving fluidity, injectability, and coatability. Examples of silicon dioxide include colloidal silica, hydrophobic silica (e.g., Cabosil (registered trademark) TS720 manufactured by Cabot Japan Co., Ltd.), spherical silica (e.g., high-purity synthetic spherical silica SE5200SEE manufactured by Admatechs Co., Ltd.), and nanosilica. Two or more types of silicon dioxide having different types or different particle sizes may be used in combination, or one type may be used alone.

[0045] Examples of organic fillers include at least one selected from the group consisting of acrylic particles, polymethyl methacrylate, polystyrene (polystyrene beads), copolymers obtained by copolymerizing the monomers constituting these (i.e., methyl methacrylate or styrene) with other monomers, polyethylene particles, polysiloxane resin particles, polyamide particles, polyester microparticles, polyurethane microparticles, and rubber microparticles (acrylic rubber particles, isoprene rubber particles). The organic filler may have a core-shell structure. The polysiloxane resin particles may be silicone particles. From the viewpoint of adhesion, the organic filler is preferably rubber microparticles, and rubber microparticles having a core-shell structure are particularly preferred. When the filler is organic, the weight-average molecular weight of the organic filler is not particularly limited, but is preferably 50,000 to 4,000,000, and particularly preferably 300,000 to 3,000,000. The weight-average molecular weight can be determined by gel permeation chromatography (GPC) using a calibration curve based on standard polystyrene.

[0046] The average particle size of the filler is not particularly limited, but is preferably 0.01 μm or more and less than 10 μm, and particularly preferably 0.012 μm or more and 5 μm or less, in order to improve fluidity, injectability, coatability, adhesion, etc. The average particle size of the filler can be measured using a laser diffraction particle size distribution analyzer, a dynamic light scattering nanotrack particle size distribution analyzer, etc. The average particle size may be the 50% cumulative particle size in a volume-based particle size distribution, or may be the 50% cumulative particle size in a number-based particle size distribution.

[0047] (G) Coupling Agent A coupling agent has two or more different functional groups in its molecule, one of which is a functional group that chemically bonds with an inorganic material, and the other is a functional group that chemically bonds with an organic material. By including a coupling agent in the curable resin composition, the adhesion of the curable resin composition can be improved when bonding different materials, such as in a camera module or a sensor module.

[0048] Examples of the coupling agent include, but are not limited to, a silane coupling agent, an aluminum coupling agent, a titanium coupling agent, etc. One type of coupling agent may be used, or two or more types may be used in combination.

[0049] Examples of functional groups contained in the silane coupling agent include a vinyl group, an epoxy group, a styryl group, a methacryl group, an acrylic group, an amino group, an isocyanurate group, a ureido group, a mercapto group, a sulfide group, and an isocyanate group. Examples of the silane coupling agent include silane compounds having an epoxy group and an alkoxy group, and which may have an alkyl group, such as 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane; silane compounds having an alkenyl group and an alkoxy group, and which may have an alkyl group, such as vinyltrimethoxysilane and p-styryltrimethoxysilane; silane compounds having a (meth)acrylic group and an alkoxy group, and which may have an alkyl group, such as 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, and 3-acryloxypropyltrimethoxysilane; N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(amino silane compounds having a primary or secondary amino group and an alkoxy group, and optionally an alkyl group, such as N-(1,3-dimethyl-butylidene)propylamine, N-(2-(ethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, and N-phenyl-3-aminopropyltrimethoxysilane; and silane compounds having one or more groups selected from the group consisting of a mercapto group, an isocyanato group, a ureido group, and a halogen atom, and one or more alkoxy groups, and optionally an alkyl group, such as 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, and 3-isocyanatopropyltriethoxysilane.

[0050] (H) Ion trapping agent The ion trapping agent captures free iodonium ions and improves the reliability of the cured product in various ways. There are no particular restrictions on the ion trapping agent, and it can be selected from those commonly used as materials for sealing materials and the like. Specific examples include hydrotalcites, and hydrated oxides of elements such as magnesium, aluminum, titanium, zirconium, and bismuth. Commercially available products include IXEPLAS-A1 and IXEPLAS-A2 manufactured by Toagosei Co., Ltd. One type of ion trapping agent may be used, or two or more types may be used in combination.

[0051] (I) Colorant A colorant can be used for the purpose of coloring the curable resin composition. Examples of colorants that can be used include pigments, dyes, and pigments. Known colorants such as red, blue, green, yellow, black, and white can be used as the colorant. Examples of pigments that can be used include black colorants such as carbon black, graphite, iron oxide, titanium black, anthraquinone, cobalt oxide, copper oxide, manganese, antimony oxide, nickel oxide, perylene, aniline, molybdenum sulfide, and bismuth sulfide. Commercially available pigments include Titanium Black 13M, 13M-C, and 13M-T manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.

[0052] Examples of optional components include (G) coupling agent, (H) ion trapping agent, and (I) colorant, as well as additives, leveling agents, antioxidants, antifoaming agents, thixotropic agents, viscosity modifiers, flame retardants, colorants, and solvents.

[0053] In order to obtain a cured product having a low Tg by heating at a low temperature of, for example, 100° C. or less, preferably 80° C. or less, the amount of component (A) in the curable resin composition is preferably 90% by mass or more, or may be 91% by mass or more, or may be 92% by mass or more, relative to the total amount of components (A), (B), and (C) (100% by mass). The total amount of components (B) and (C) is preferably 10% by mass or less, or may be 9% by mass or less, or may be 8% by mass or less, or is preferably 1% by mass or more, or may be 2% by mass or more, or may be 3% by mass or more, relative to the total amount of components (A), (B), and (C).

[0054] In order to obtain a cured product having a low Tg by curing at a low temperature of, for example, 100°C or less, preferably 80°C or less, relative to 100% by mass of the total amount of the curable resin composition, the total amount of component (A), component (B), and component (C) is preferably 50 to 100% by mass, more preferably 55 to 95% by mass, and even more preferably 60 to 90% by mass.

[0055] When the curable resin composition contains, as the cationic curable resin (A) in the composition, at least one selected from the group consisting of an epoxy resin having a ring skeleton in the molecule (A1) and an oxetane resin (A2), the total amount of components (A1) and (A2) is preferably 20 to 100% by mass, more preferably 30 to 90% by mass, and even more preferably 30 to 70% by mass, when the total amount of component (A) is taken as 100% by mass. In order to obtain a cured product having a low elastic modulus, component (A) may be entirely at least one component selected from the group consisting of components (A1) and (A2), or the total amount of components (A1) and (A2) may be 100% by mass when the total amount of component (A) is taken as 100% by mass. When the total amount of component (A1) and component (A2) in component (A) is less than 100 mass%, the remainder excluding component (A1) and component (A2) may be at least one selected from the group consisting of epoxy resins not having a ring skeleton in the molecule (e.g., aliphatic epoxy resins), polystyrene-based compounds, and vinyl ether compounds.

[0056] When component (A) in the curable resin composition contains an epoxy resin, and the epoxy resin contains component (A1) an epoxy resin having an aromatic ring skeleton, the epoxy resin can be cured by heating at a low temperature, for example, 100°C or lower, preferably 80°C or lower, to obtain a cured product in the form of a thin film having a low Tg and a low elastic modulus, for example, 100 μm or less, and the amount of the epoxy resin having an aromatic ring skeleton in component (A) is preferably 20 to 100 mass%, more preferably 15 to 95 mass%, and even more preferably 20 to 95 mass%, when the total amount of component (A) is taken as 100 mass%.

[0057] When component (A) in the curable resin composition contains an epoxy resin, and the epoxy resin contains component (A1), an epoxy resin having an aromatic ring skeleton and an epoxy group equivalent of 200 g / eq or less, the ratio 1 of the number of epoxy group equivalents of component (A1) to the number of functional group equivalents in component (A) (functional group equivalent ratio 1 = [number of epoxy group equivalents of component (A1) having an epoxy group equivalent of 200 g / eq or less] / [number of functional group equivalents of component (A)]) is preferably 0.001 to 0.8, more preferably 0.01 to 0.6, and even more preferably 0.05 to 0.4, in order to obtain a cured product having a low Tg and a low elastic modulus by curing at a low temperature, for example, 100°C or less, and preferably 80°C or less. The number of functional group equivalents in component (A) refers to the total number of functional group equivalents contained in component (A), and when component (A) contains, for example, both an epoxy resin and an oxetane resin, it refers to the total number of epoxy group equivalents and oxetane group equivalents.

[0058] When component (A) in the curable resin composition contains an epoxy resin, and the epoxy resin contains component (A1) an epoxy resin having an aromatic ring skeleton and an epoxy group equivalent of more than 200 g / eq, in order to obtain a cured product having a low Tg and a low elastic modulus by curing at a low temperature, for example, 100°C or less, preferably 80°C or less, the ratio of the number of epoxy group equivalents of component (A1) to the number of functional group equivalents of component (A) (functional group equivalent ratio 2=[number of epoxy group equivalents of component (A1) having an epoxy group equivalent of more than 200 g / eq] / [number of functional group equivalents of component (A)]) is preferably 0.01 to 1.0, more preferably 0.1 to 0.9, and even more preferably 0.2 to 0.8.

[0059] When component (A) in the curable resin composition contains an epoxy resin, in order to obtain a cured product having a low Tg and a low elastic modulus by curing the composition by heating at a low temperature, for example, 100°C or less, preferably 80°C or less, the amount of the epoxy resin having an alicyclic skeleton in component (A) is preferably 0 to 50% by mass, more preferably 0 to 40% by mass, and even more preferably 1 to 30% by mass, when the total amount of component (A) is taken as 100% by mass.

[0060] When component (A) in the curable resin composition contains an epoxy resin, and the epoxy resin contains component (A1), an epoxy resin having an alicyclic skeleton, in order to obtain a cured product having a low Tg and a low elastic modulus by curing at a low temperature, for example, 100°C or lower, preferably 80°C or lower, the ratio 3 of the number of epoxy group equivalents of the epoxy resin of component (A1) having an alicyclic skeleton to the number of functional group equivalents of component (A) (functional group equivalent ratio 3 = [number of epoxy group equivalents of component (A1) having an alicyclic skeleton] / [number of functional group equivalents of component (A)]) is preferably 0.001 to 0.5, more preferably 0.01 to 0.5, and even more preferably 0.05 to 0.3.

[0061] Component (A) in the curable resin composition contains an epoxy resin, and the amount of the epoxy resin having an alicyclic skeleton in component (A) may be 0 to 70 mass % or 0 to 60 mass % when the total amount of component (A) is taken as 100 mass %.

[0062] When component (A) in the curable resin composition contains an epoxy resin and component (A1) contains an aliphatic cyclic epoxy resin, in order to obtain a cured product having a low Tg by curing at a low temperature, for example, 100°C or lower, preferably 80°C or lower, the ratio 4 of the epoxy group equivalent number of the epoxy resin of component (A1), which is an aliphatic cyclic epoxy resin, to the functional group equivalent number of component (A) (functional group equivalent ratio 4 = [epoxy group equivalent number of component (A1), which is an aliphatic cyclic epoxy resin] / [functional group equivalent number of component (A)]) is preferably 0.01 to 0.8, more preferably 0.1 to 0.6, and even more preferably 0.1 to 0.4.

[0063] In component (A) in the curable resin composition, the oxetane resin of component (A2) is preferably 0 to 40% by mass, more preferably 0 to 30% by mass, and even more preferably 0 to 20% by mass, when the total amount of component (A) is taken as 100% by mass. When component (A2) contains the oxetane resin, the content of component (A2) is preferably 1 to 40% by mass, more preferably 2 to 30% by mass, and more preferably 3 to 20% by mass, when the total amount of component (A) is taken as 100% by mass, in order to accelerate the curing rate and efficiently obtain a cured product having a low Tg by curing at a low temperature, for example, of 100°C or less, preferably 80°C or less.

[0064] When component (A) in the curable resin composition contains an oxetane resin of component (A2), in order to obtain a cured product having a low Tg by curing at a low temperature, for example, 100°C or less, preferably 80°C or less, the ratio 5 of the number of oxetane group equivalents of the oxetane resin of component (A2) to the number of functional group equivalents of component (A) (functional group equivalent ratio 5 = [number of oxetane group equivalents of component (A2)] / [number of functional group equivalents of component (A)]) is preferably 0.01 to 0.5, more preferably 0.05 to 0.4, and even more preferably 0.1 to 0.3.

[0065] The blending ratio of component (A1) to component (A2) in component (A) in the curable resin (component (A1):component (A2)) is preferably 100:0 to 60:40 by mass, more preferably 99:1 to 70:30, and even more preferably 98:2 to 80:20. When the blending ratio of component (A1) to component (A2) in component (A) is 100:0 to 60:40, the component can be cured by heating at a low temperature, for example, 100°C or less, preferably 80°C or less, to obtain a cured product having a low Tg.

[0066] In order to cure the curable resin by heating at a low temperature, for example, 100°C or less, preferably 80°C or less, the amount of component (B) in the curable resin is preferably 0.1 to 10.0 parts by mass, more preferably 0.5 to 8 parts by mass, and even more preferably 1.0 to 5 parts by mass, relative to 100 parts by mass of component (A).

[0067] In order to cure the curable resin by heating at a low temperature, for example, 100°C or less, preferably 80°C or less, the amount of component (C) in the curable resin is preferably 0.1 to 10.0 parts by mass, more preferably 0.5 to 8 parts by mass, and even more preferably 1.0 to 5 parts by mass, per 100 parts by mass of component (A).

[0068] The blending ratio of component (B) and component (C) in the curable resin (component (B):component (C)) is preferably approximately equal, and may be a mass ratio of 25:75 to 75:25, 30:70 to 70:30, 40:60 to 60:40, or 50:50.

[0069] The amount of the photosensitizer of component (D) in the curable resin composition may be 0 to 3.0 mass%, 0.05 to 3.0 mass%, 0.05 to 2.0 mass%, or 0.1 to 1.0 mass%, relative to 100 mass% of the total amount of the curable resin composition.

[0070] The amount of the photoradical generator of component (E) in the curable resin composition may be 0 to 3.0 mass%, 0.05 to 3.0 mass%, 0.05 to 2.0 mass%, or 0.1 to 1.0 mass%, relative to 100 mass% of the total amount of the curable resin composition.

[0071] The amount of the filler of component (F) in the curable resin composition may be 0 to 50% by mass, 1 to 45% by mass, or 3 to 40% by mass, relative to 100% by mass of the total amount of the curable resin composition. For example, in order to obtain a cured product in the form of a thin film of 100 μm or less, preferably 50 μm or less, and to obtain a cured product having a low Tg by curing the composition by heating at a low temperature of, for example, 100° C. or less, preferably 80° C. or less, the amount of the filler of component (F) in the curable resin composition is preferably 1 to 45% by mass, more preferably 3 to 40% by mass, relative to 100% by mass of the total amount of the curable resin composition.

[0072] The amount of the optional components in the curable resin composition is 10% by mass or less, and may be 0 to 10% by mass, 0.1 to 5% by mass, or 0.3 to 3% by mass, relative to 100% by mass of the total amount of the curable resin composition. As described above, the optional components may include at least one selected from the group consisting of (G) a coupling agent, (H) an ion trapping agent, and (I) a colorant.

[0073] Method for Producing Curable Resin Composition The curable resin composition can be produced by mixing components (A), (B), and (C). The curable resin composition can also be produced by further mixing components (D), (E), (F), (G), (H), (I), and other optional components as needed. The curable resin composition may be produced by mixing the components together with additives as needed. The components can be introduced simultaneously or separately into an appropriate mixer, and stirred and mixed while melting by heating if necessary to obtain a curable resin composition. The method for producing the curable resin composition is not particularly limited. The curable resin composition can be produced by mixing the raw materials for each component using a mixer such as a Raikai mixer, Henschel mixer, roll mill, three-roll mill, ball mill, planetary mixer, or bead mill equipped with a stirrer and a heater. The curable resin composition may also be produced using an appropriate combination of two or more devices.

[0074] The curable resin composition is preferably liquid or paste-like at room temperature, for example, 20°C to 30°C. The viscosity of the curable resin composition is preferably 200 Pa s or less, or may be 190 Pa s or less, or preferably 1 Pa s or more, measured using a Brookfield rotational viscometer (HBDV-I or RVDV-I type, spindle: SC4-14 spindle, rotation speed: 50 rpm, measurement temperature: 25°C) immediately after preparation (for example, within 30 minutes) and after leaving for a predetermined time at room temperature, for example, 20°C to 30°C. The viscosity of the curable resin composition measured by the above-mentioned method at 20°C to 30°C may be 3 Pa s to 10 Pa s.

[0075] Adhesive or sealant The curable resin composition can be used as an adhesive or sealant for fixing, joining, or protecting components constituting an electronic device, a camera module, or a sensor module, and can also be used as an adhesive or sealant containing a curable resin composition.

[0076] Method for Supplying Curable Resin Composition The curable resin composition can be supplied using a jet dispenser, an air dispenser, etc. Alternatively, the curable resin composition can be supplied by a known coating method (dip coating, spray coating, bar coater coating, gravure coating, reverse gravure coating, spin coater coating, etc.) or a known printing method (lithographic printing, carton printing, metal printing, offset printing, screen printing, gravure printing, flexographic printing, inkjet printing, etc.).

[0077] Curing conditions for curable resin composition The resin composition is thermosetting and can be cured by heating at 100°C or less, preferably 80°C or less, more preferably 75°C or less, even more preferably 70°C or less, preferably 45°C or more, more preferably 55°C or more, and even more preferably 60°C or more. The heating time for curing the curable resin composition is preferably 15 minutes to 4 hours, more preferably 30 minutes to 2 hours, and even more preferably 30 minutes to 60 minutes. The curable resin composition can be heated using a blower dryer or a hot plate.

[0078] Cured Product A cured product can be obtained by curing a curable resin composition, or an adhesive or sealant containing the curable resin composition. The cured product obtained by curing the curable resin composition at 80°C for 60 minutes preferably has a glass transition temperature (Tg) of 0°C to 100°C, more preferably 1°C to 90°C, even more preferably 2°C to 80°C, even more preferably 3°C to 70°C, and particularly preferably 5°C to 60°C, as measured using a dynamic viscoelasticity measuring device (e.g., DMA7100 manufactured by Hitachi High-Tech Science Corporation). Even if the Tg of the resulting cured product is 100°C or less, it can be cured at low temperatures, and a thin-film cured product having a thickness of 100 μm or less can be obtained. The glass transition temperature can be measured by referring to the method described in the Examples below. The cured product obtained by curing the curable resin composition at 80°C for 60 minutes preferably has a storage modulus (E') of 5 GPa or less, or may be 4.5 GPa or less, preferably 0.01 GPa or more, and more preferably 0.02 GPa or more, as measured using a dynamic viscoelasticity measuring device (e.g., DMA7100 manufactured by Hitachi High-Tech Science Corporation). The smaller the storage modulus (E'), the softer the cured product is, and even when adhering adherends made of different materials, the cured product has the ability to follow the expansion and contraction of the adherends, which differ depending on the linear expansion coefficients of the adherends.

[0079] Semiconductor Devices, Electronic Devices When the curable resin composition, or an adhesive or encapsulant containing the curable resin composition, is used to fix, bond, or protect electronic components, an electronic device containing a cured product obtained by curing the curable resin composition, or the adhesive or encapsulant containing the curable resin composition, can be obtained. The electronic device may be a semiconductor device containing a semiconductor element. Examples of electronic devices include mobile phones, smartphones, laptops, tablet terminals, and camera modules. By using the curable resin composition, or the adhesive or encapsulant containing the curable resin composition to fix, bond, or protect electronic components, it is possible to provide an electronic device that has a low Tg that can be cured by heating at a low temperature of, for example, 100°C or less, preferably 80°C or less, a low storage modulus, excellent tracking, and high reliability.

[0080] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0081] The components used in the curable resin compositions of the Examples and Comparative Examples are shown below.

[0082] Component (A): Cationic curable resin Component (A1): Epoxy resin having a ring structure in the molecule (A1-1): AER9000 (manufactured by Asahi Kasei Corporation), a special epoxy resin containing a compound in which a polyalkylene oxide structure is added to an epoxy resin and bisphenol A skeleton, with a molecular weight of 760 and an epoxy group equivalent of 380 g / eq. (A1-2): EPICLON (registered trademark) EXA-850CRP (manufactured by DIC Corporation), a bisphenol A-type epoxy resin with a molecular weight of 344 and an epoxy group equivalent of 172 g / eq. (A1-3): ADEKA GLYCIROL (registered trademark) ED-509S (manufactured by ADEKA Corporation), p-tert-butylphenyl glycidyl ether, with a molecular weight of 206 and an epoxy group equivalent of 206 / eq. (A1-4): jER YX8000 (manufactured by Mitsubishi Chemical Corporation), hydrogenated bisphenol A diglycidyl ether, molecular weight 410, epoxy group equivalent weight 205 g / eq. (A1-5): CELLOXIDE (registered trademark) 2021P (manufactured by Daicel Corporation), 3',4'-epoxycyclomethyl 3,4-epoxycyclohexane carboxylate, molecular weight 260, epoxy group equivalent weight 130 g / eq.

[0083] Component (A): Cationic curable resin Component (A2): Oxetane resin (A2-1): OXT-221 (manufactured by Toagosei Co., Ltd.), 3-ethyl-3{[(3-ethyloxetan-3-yl)methoxy]methyl}oxetane, molecular weight 214, oxetane group equivalent 107 g / eq. (A2-2): OXT-101 (manufactured by Toagosei Co., Ltd.), 3-ethyl-3-hydroxymethyloxetane (oxetane alcohol), molecular weight 116, oxetane group equivalent 116 g / eq.

[0084] Component (B): Acid generator containing an iodonium salt (B-1): Bluesil (registered trademark) PI2074 (manufactured by Elkem Silicones), 4-isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate (B-2): IK-1FG (manufactured by San-Apro Co., Ltd.)

[0085] Component (C): Peroxydicarbonate-type organic peroxide (C-1): Perkadox 24L (manufactured by Nouryon), dicetyl peroxydicarbonate, 1-hour half-life temperature of 65°C, molecular weight of 570.9, SADT of 40°C, solid (powder) at room temperature (about 20°C to about 25°C). (C-2): Perloyl TCP (manufactured by NOF Corporation), di(4-tert-butylcyclohexyl) peroxydicarbonate, 1-hour half-life temperature of 58°C, molecular weight of 398.5, SADT of 45°C, solid (powder) at room temperature (about 20°C to 25°C). (C-3): Luperox 225 (manufactured by Arkema Yoshitomi Co., Ltd.), di(secondary butyl) peroxydicarbonate, 1-hour half-life temperature 69°C, molecular weight 234.2, SADT 16°C, liquid at room temperature (approximately 20°C to 25°C). (C-4): Ditridecyl peroxydicarbonate (manufactured by Alfa Chemistry), molecular weight 486.72, solid (powder) at room temperature (approximately 20°C to 25°C). (C-5): Distearyl peroxydicarbonate (manufactured by SAGECHEM LIMITED), molecular weight 626.99, solid (powder) at room temperature (approximately 20°C to 25°C).

[0086] Component (C'): Alkyl peroxy ester type organic peroxide (C'-1): Perocta O (manufactured by NOF Corporation), 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, one-hour half-life temperature of 84°C, molecular weight of 272.4, SADT of 40°C. (C'-2): Luperox 10 (manufactured by Arkema Yoshitomi Co., Ltd.), t-butyl peroxydecanoate, one-hour half-life temperature of 66°C, molecular weight of 430.6, SADT of 27°C. The one-hour half-life temperature, molecular weight, and SADT values ​​of each organic peroxide are listed from the catalog.

[0087] (D) Photosensitizer (D-1): DETX, 2,4-diethylthioxanthone (manufactured by Nippon Kayaku Co., Ltd.)

[0088] (E) Photoradical Generator (E-1): Omnirad (registered trademark) 184 (manufactured by IGM Resins), 1-hydroxycyclohexyl phenyl ketone

[0089] (F) Filler (F-1): SE5200SEE (manufactured by Admatechs Co., Ltd.), high-purity synthetic spherical silica. (F-2): Cabosil (registered trademark) TS720 (manufactured by Cabot Japan Co., Ltd.), hydrophobic silica.

[0090] (G) Coupling Agent (G-1): Silane coupling agent, S530 (manufactured by JNC Corporation), 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane.

[0091] (H) Ion trapping agents (H-1): IXEPLAS-A1 (manufactured by Toagosei Co., Ltd.), a zirconium-magnesium based ion trapping agent. (H-2): IXEPLAS-A2 (manufactured by Toagosei Co., Ltd.), a zirconium-magnesium based ion trapping agent.

[0092] (I) Colorant (I-1): Titanium Black 13M (manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.)

[0093] Examples 1 to 12 and Comparative Examples 1 to 6 Curable resin compositions were prepared by mixing the respective amounts of each component using a three-roll mill according to the blending ratios shown in Tables 1 and 2. In Tables 1 and 2, the numbers indicating the blending ratio of each component contained in the curable resin composition represent mass % relative to 100 mass % of the total amount of the curable resin composition, unless otherwise specified. In the tables, each component is represented by the product name or trade name, mainly represented by a symbol.

[0094] In the examples and comparative examples, the properties of the curable resin compositions and cured products were measured as follows. The results are shown in Tables 1 to 3. In the tables, the symbol "-" indicates that the corresponding component was not contained in the curable resin composition. Table 3 lists examples and comparative examples of curable resin compositions that do not contain a filler. Some examples and comparative examples are listed in Table 2 or Table 3.

[0095] Preparation of Cured Products Each of the curable resin compositions of Examples 1 to 12 and Comparative Examples 1 to 6 was heated at 80° C. for 60 minutes using an air dryer to obtain a cured product.

[0096] Examples 13 and 14 Resin compositions of Examples 13 and 14 were produced in the same manner as in Example 1, except that the component (C-1) used in Example 1 was replaced with components (C-4) and (C-5), respectively. The properties of the resin compositions of Examples 13 and 14 and the cured products obtained by curing the resin compositions were measured in the same manner as in Example 1. It is expected that in Examples 13 and 14, the test pieces for thin-film cured product testing also cure up to the thinnest edge, preventing partial curing failure.

[0097] Shear Strength A resin composition was applied to a lower substrate (a smooth plate of liquid crystal polymer (LCP): 74 mm long, 20 mm wide, and 2 mm thick) by stencil printing to a size of φ2 mm and a thickness of 125 μm. A 3.2 mm × 1.6 mm × 0.45 mm alumina chip was laminated on the applied resin composition, and the resin composition was cured under a light load to prepare a test piece. The curing conditions were 80 ° C. and 60 minutes in a blower dryer. The shear strength of the obtained test piece was measured at 23 ° C. using a universal bond tester (Series 4000: manufactured by Nordson Advanced Technologies). Specifically, stress (unit: N) was measured at a test speed of 200 μm / s using a universal bond tester. The shear strength when a liquid crystal polymer (LCP) was used as the lower substrate and the upper substrate was taken as the LCP shear strength. This measurement was performed on 10 test pieces, and the average value of the obtained stress was calculated. This average value was defined as the shear strength (unit: N) of the cured product. In addition, the shear strength when polyphthalamide (PPA) was used as the lower substrate and upper substrate instead of liquid crystal polymer (LCP) and the lower substrate had the same size as the liquid crystal polymer was defined as the PPA shear strength.

[0098] Curability at 80°C First, a Teflon (registered trademark) sheet was attached to the surface of a 3 mm thick glass plate, and spacers (heat-resistant tape laminated thereon) were placed in two locations so that the film thickness upon curing would be 400±150 μm. Next, the curable resin composition was applied between the spacers, and the composition was sandwiched between two glass plates with Teflon (registered trademark) sheets attached to the surface to prevent air bubbles from being trapped. The composition was then heated in a fan dryer at 80°C for 60 minutes to cure. By sandwiching the composition between glass plates, the curability could be evaluated without considering the influence of oxygen inhibition. If the curable resin composition was cured and had no tackiness, it was rated as good (Good, "G"); if it was cured but had tackiness, it was rated as insufficient (Poor, "P"); and if it was liquid and not cured, it was rated as not good (Bad, "B"). Tackiness was confirmed by touching with a finger.

[0099] Cured Length and Cured Film Thickness of Test Pieces for Thin-Film Cured Product Testing FIG. 1 shows a method for manufacturing test pieces for testing thin-film cured products of curable resin compositions. As shown in FIG. 1, 50 μm-thick tape 2 was placed 10 mm apart from the edge 1a of substrate 1, creating a step of the thickness of tape 2. Tape 2 was attached to substrate 1 so as not to move. Substrate 1 was made of liquid crystal polymer (LCP) and measured 2 mm thick, 20 mm wide, and 74 mm long. Tape 2 was made of polyimide. A squeegee was moved from tape 2 toward one edge 1a of substrate 1 to apply the curable resin composition in a fillet shape with an approximately triangular edge, producing a coated product. The coated product was heated at 80°C for 60 minutes using a blower dryer to produce test pieces 3 for testing thin-film cured products with approximately triangular edge surfaces. After heating at 80°C for 60 minutes, the prepared test piece 3 was visually inspected, and the cured length of the test piece 3 from the tape 2 toward one end 1a of the substrate 1 was measured and recorded as the cured length (mm) of the test piece. The thinner the test piece 3, the slower the polymerization reaction in the curable resin composition progresses, making it more difficult to cure. The thin-film test piece 3 allows visual confirmation of cured and uncured portions. Since the end faces of the test piece 3 for the thin-film cured product test are approximately triangular, the thinnest thickness of the cured portion of the test piece 3 was measured as the cured film thickness using the following conversion formula, based on the cured length of the test piece 3 from the tape 2 side, where the thickness of the test piece 3 is the thickest, toward the end 1a of the substrate 1, where the thickness of the test piece 3 is the thinnest: Cured film thickness (μm) = 5 × (maximum cured length of the test piece 10 mm - cured length of the test piece (mm)). In Tables 1 and 2, in the above conversion formula, a cured film thickness of 0 μm was considered to be cured to the end and was recorded as A. The numerical values ​​are the cured film thickness (μm) measured using the above conversion formula. Those that did not cure are recorded as F.

[0100] The storage modulus (E') and glass transition temperature (Tg) of the cured product were measured in accordance with Japanese Industrial Standard JIS C6481. Specifically, a Teflon (registered trademark) sheet was first attached to the surface of a 3 mm thick glass plate, and spacers (heat-resistant tape laminated thereon) were placed in two locations so that the film thickness upon curing would be 400±150 μm. Next, the curable resin composition was applied between the spacers, and the glass plate was sandwiched between two other glass plates with Teflon (registered trademark) sheets attached to their surfaces, taking care not to trap air bubbles. The glass plate was then heated at 80°C for 60 minutes in an air dryer to obtain a cured product in which the curable resin composition was cured. Finally, the cured product was peeled from the Teflon (registered trademark) sheet-attached glass plate and cut to the specified dimensions (10 mm long, 40 mm wide) with a cutter to obtain a test piece. The cut edges were smoothed with sandpaper. The initial Tg of this cured product was measured using a dynamic viscoelasticity measuring apparatus (DMA) (manufactured by Hitachi High-Tech Science Corporation) in the range of -20°C to 200°C, at a frequency of 10 Hz, a heating rate of 3°C / min, and a strain amplitude of 5 μm using a tensile method. The storage modulus (E') and loss modulus (E") of the cured product were measured, and the Tg was determined as the peak temperature of the dielectric dissipation factor (tan δ) calculated from E" / E'.

[0101]

[0102]

[0103]

[0104] As shown in Tables 1 to 3, the cured products of each curable resin composition of Examples 1 to 11 had higher LCP shear strength and PPA shear strength and superior adhesion to adherends compared to the cured products of the curable resin compositions of Comparative Examples 1 and 2. Furthermore, in Examples 1 to 3 and 5 to 11, the cured length of the thin-film curing test was as long as 10 mm, and the test specimens for the thin-film cured product test, which had approximately triangular end faces, were cured to the thinnest end, preventing partial curing failure. The cured product of the curable resin composition of Example 4 had a cured length of 6 mm and a cured film thickness of 20 μm. This is thought to be because the peroxydicarbonate-type organic peroxide of component (C-3) is liquid at room temperature, and therefore remains as a low molecular weight compound in the resin composition after decomposition by reaction, resulting in poor curing of the resin composition. On the other hand, since the peroxydicarbonate-type organic peroxide of component (C-1) or component (C-2) is solid at room temperature, it remains solid even after decomposition during the reaction, and it is thought that this does not inhibit the thin-film curing properties of the resin composition even after decomposition. As a result, curing occurred up to the edge of the cured film thickness, which is difficult to cure. Furthermore, the cured products of each of the curable resin compositions of Examples 1 to 9 and 11 had low Tg values ​​of 0°C to 100°C, and were cured by heating at a low temperature of 80°C or less to obtain cured products with low Tg values. The cured product of the curable resin composition of Example 10 had a slightly higher Tg of 117°C, but a cured product with a Tg of 120°C or less was obtained. The cured products of the curable resin compositions of Examples 1 to 11 had low storage moduli (E') of 0.02 GPa to 5.0 GPa, and were able to follow the expansion and contraction of the adherend.

[0105] As shown in Table 3, the curable resin composition of Example 12 and the curable resin composition of Comparative Example 3, which did not contain the filler (F), exhibited reduced coatability and adhesion, and were unable to form a coating with a triangular edge, making it impossible to measure the cured film thickness. Therefore, as another test to evaluate thin-film curability, a coating was formed into a 50 μm thick, 5 mm wide strip to produce a cured product. The strip-shaped cured product was touched to determine whether it had cured or not. The results are listed in Table 2 as a thin-film curing test. The strip-shaped cured product was touched with the finger, and if it had cured, it was rated as good (Good, "G"); if it had not cured and was liquid, it was rated as bad (B"). The cured product of the curable resin composition of Example 12, even though it did not contain the filler (F), exhibited the curability of a thin film cured product with a film thickness of 50 μm. The cured products of the curable resin compositions of Examples 11 and 12 had a low Tg of 0°C to 100°C, and were cured by heating at a low temperature of 80°C or less to obtain cured products having a low Tg. The cured products of the curable resin compositions of Examples 11 and 12 had a low storage modulus (E') of 0.1 GPa to 1.0 GPa, and were able to follow the expansion and contraction of an adherend.

[0106] As shown in Tables 2 and 3, the cured products of the curable resin compositions of Comparative Examples 1 to 6, which contained a non-peroxydicarbonate organic peroxide as the organic peroxide, exhibited low LCP shear strength and PPA shear strength, suggesting that the cured products of Comparative Examples 1 and 2 were affected by oxygen inhibition, did not cure sufficiently, and did not exhibit strength. Furthermore, the cured products of Comparative Examples 1, 2, 4, and 5 did not cure in thin film form, with a cured length of 0 mm in the thin film curing test. The cured product of Comparative Example 2 had a storage modulus (E') exceeding 5.0 GPa, suggesting poor compliance with the expansion and contraction of the adherend. Furthermore, the cured product of Comparative Example 6, which did not contain filler (F), did not cure even when formed into a strip shape.

[0107] The curable resin composition according to the present invention can be suitably used as an adhesive or sealant for fixing, joining, or protecting components constituting an electronic device. The resin composition according to an embodiment of the present invention, an adhesive or sealant containing the resin composition, a cured product obtained by curing the die attach agent, and an electronic device containing the cured product can be used in, for example, mobile phones, smartphones, laptop computers, tablet terminals, camera modules, sensor modules, etc.

[0108] 1: Substrate, 2: Tape, 3: Test piece

Claims

1. (A) Cationic curable resin, (B) Acid generator containing an iodonium salt, (C) A curable resin composition containing a peroxydicarbonate-type organic peroxide.

2. The aforementioned component (A) is (A1) Epoxy resin having a ring skeleton in its molecule, and (A2) The curable resin composition according to claim 1, comprising at least one selected from the group consisting of oxetane resins.

3. The curable resin composition according to claim 2, wherein the component (A1) has an aromatic ring skeleton.

4. The curable resin composition according to any one of claims 1 to 3, wherein the 1-hour half-life temperature of component (C) is 50°C to 80°C.

5. The curable resin composition according to any one of claims 1 to 3, wherein the iodonium salt contained in component (B) is an iodonium salt compound represented by the following formula (1). 【Chemistry 1】 (In formula (1) above, Ar １ and Ar ２ Each of these is independently a substituted or unsubstituted aryl group, and Z － (This is an anion.)

6. Z in the above formula (1) － is BF ４ － 、SbF ６ −、AsF ６ － 、B(C ６ F ５ ) ４ － 、or Ga(C ６ F ５ ) ４ － 、C(CF ３ SO ２ ) ３ － 、or [P(R ３ ) ａ F ６－ａ － 、[C(R ３ SO ２ ) ３ － 、or [N(R ３ SO ２ ) ２ － (In the formula, R ３ is each independently an alkyl group in which at least a part of hydrogen atoms are substituted with fluorine atoms, a is an integer of 0 to 5, and when a is an integer of 2 or more, a plurality of R ３ may be the same as or different from each other.) The curable resin composition according to claim 5.​​​

7. The curable resin composition according to claim 2 or 3, wherein the component (A1) comprises an epoxy resin having an epoxy group equivalent of 100 g / eq to 1000 g / eq.

8. An adhesive or sealant comprising the curable resin composition according to any one of claims 1 to 3.

9. A cured product obtained by curing the curable resin composition according to any one of claims 1 to 3, or the adhesive or sealant according to claim 8.

10. The cured product according to claim 9, wherein the glass transition temperature (Tg) of the cured product is 0°C to 100°C.

11. A semiconductor device comprising the cured product described in claim 9.

12. An electronic device comprising the cured product described in claim 9.

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