Thermosetting resin composition, cured product, semiconductor sealing material, semiconductor device, insulating material for printed wiring board, printed wiring board, and capsule-like modifier

Abstract

The present disclosure provides: a thermosetting resin composition which has high dispersibility of a modified resin; and the like.　The present disclosure provides: a thermosetting resin composition which contains a thermosetting resin (A), a curing agent (B), a modifier (C), and at least one filler (D) that is selected from the group consisting of inorganic fine particles and fibers, wherein the modifier (C) has a capsule structure that has a core and a shell covering the surface of the core, and the core contains a modified resin (c); a cured product of the thermosetting resin composition; and a semiconductor sealing material, a semiconductor device, an insulating material for a printed wiring board, and a printed wiring board, each of which contains the thermosetting resin composition.　The present disclosure also provides a capsule-like modifier which has a core and a shell that covers the surface of the core, wherein the core contains a modified resin.

Description

Thermosetting resin composition, cured product, semiconductor encapsulant, semiconductor device, insulating material for printed wiring board, printed wiring board, and encapsulated modifier

[0001] The present disclosure relates to a thermosetting resin composition, a cured product, a semiconductor encapsulant, a semiconductor device, an insulating material for printed wiring boards, a printed wiring board, and an encapsulated modifier.

[0002] Thermosetting resins are used in a wide range of fields, including as encapsulating materials for protecting semiconductor elements such as capacitors, diodes, transistors, and thyristors, as well as for protecting integrated circuits such as ICs and LSIs, and as insulating materials for printed wiring boards. However, molded articles using the thermosetting resins are often composites of various different materials, and warping can occur during the manufacture of the composite due to differences in the thermal expansion coefficients of the materials, resulting in problems with dimensional accuracy. Furthermore, molded articles using the thermosetting resins can develop defects due to differences in the thermal expansion coefficients when exposed to temperature changes in the environment in which they are used, which can often pose a major manufacturing problem (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2003-82241

[0004] In order to suppress warpage and defects in molded articles using a thermosetting resin composition, there is a method of adding a modifying resin to the thermosetting resin composition. However, a thermosetting resin composition prepared by kneading a liquid modifying resin with materials such as a powdered thermosetting resin and a curing agent has a problem in that the uniform dispersion of the modifying resin is reduced.

[0005] The problem to be solved by the present disclosure is to provide a thermosetting resin composition in which the modified resin is highly uniformly dispersed.

[0006] The present disclosure provides the following embodiments. [1] A thermosetting composition comprising a thermosetting resin (A), a curing agent (B), a modifier (C), and one or more fillers (D) selected from the group consisting of inorganic fine particles and fibers, wherein the modifier (C) has a capsule structure having a core and a shell covering the surface of the core, and the core comprises a modified resin (c). [2] The thermosetting resin composition according to [1] above, wherein the modified resin (c) has an ether concentration of 11.5 mol / kg or more and 23 mol / kg or less. [3] The thermosetting resin composition according to [1] or [2] above, wherein the modified resin (c) comprises a polyetherester polyol resin and / or a urethane resin made from at least one of a polyether polyol and a polyetherester polyol. [4] The thermosetting resin composition according to any one of [1] to [3] above, wherein the modified resin (c) has a number average molecular weight of 500 or more and 20,000 or less. [5] The thermosetting resin composition according to any one of [1] to [4] above, wherein the shell comprises one or more resins selected from the group consisting of melamine resin, polyurea resin, and gelatin. [6] The thermosetting resin composition according to any one of [1] to [5] above, wherein the content of the modified resin (c) is 5% by mass or more and 45% by mass or less of the non-volatile content of the components excluding the filler (D) from the thermosetting resin composition. [7] A cured product of the thermosetting resin composition according to any one of [1] to [6] above. [8] A semiconductor encapsulant comprising the thermosetting resin composition according to any one of [1] to [6] above. [9] A semiconductor device comprising the semiconductor encapsulant according to [8] above.

[10] An insulating material for printed wiring boards comprising the thermosetting resin composition according to any one of [1] to [6] above.

[11] A printed wiring board comprising the insulating material for printed wiring boards according to

[10] above.

[12] A capsule-shaped modifier having a core and a shell covering the surface of the core, the core containing a modifying resin.

[13] The capsule-shaped modifier according to

[12] , wherein the modifying resin has an ether concentration of 11.5 mol / kg or more and 23 mol / kg or less.

[14] The capsule-shaped modifier according to

[12] or

[13] , wherein the modifying resin comprises a polyether ester polyol resin and / or a urethane resin made from at least one of a polyether polyol and a polyether ester polyol.

[15] The capsule-shaped modifier according to any one of

[12] to

[14] , wherein the shell comprises one or more materials selected from the group consisting of a melamine resin, a polyurea resin, and gelatin.

[0007] According to the present disclosure, it is possible to provide a thermosetting resin composition in which the modified resin is highly uniformly dispersed.

[0008] I. Thermosetting Resin Composition The thermosetting resin composition of the present disclosure is a thermosetting composition comprising a thermosetting resin (A), a curing agent (B), a modifier (C), and one or more fillers (D) selected from the group consisting of inorganic fine particles and fibers, wherein the modifier (C) has a capsule structure having a core and a shell covering the surface of the core, and the core contains the modifying resin (c).

[0009] According to the thermosetting resin composition of the present disclosure, by using a modifier (C) having a capsule structure in which the modified resin (c) is encapsulated, the uniform dispersion of the modifier (C) and the modified resin (c) in the thermosetting resin composition is improved. Furthermore, when the thermosetting resin composition of the present disclosure is subjected to a load such as heating or pressure (hereinafter referred to as an external load), the capsule of the modifier (C) is broken, and the encapsulated modified resin (c) is released and diffused. Therefore, in the cured product of the thermosetting resin composition, the uneven distribution of the modified resin (c) is suppressed and the modified resin (c) is uniformly dispersed, making it easier to uniformly express the performance of the modified resin (c).

[0010] Examples of the thermosetting resin (A) that can be used include epoxy resins, benzoxazine structure-containing resins, maleimide resins, vinylbenzyl compounds, acrylic compounds, and copolymers of styrene and maleic anhydride. These resins may be used alone or in combination of two or more. Among these, it is preferred that the thermosetting resin (A) contains at least an epoxy resin.

[0011] Furthermore, among the resins exemplified above, the thermosetting resin (A) is preferably an epoxy resin and / or a maleimide resin, more preferably an epoxy resin, because it is easy to form a phase-separated structure with the modified resin (c) and to achieve a low thermal expansion coefficient and a low elastic modulus in the cured product of the thermosetting resin composition.

[0012] Examples of the epoxy resin include bisphenol A type epoxy resins, bisphenol F type epoxy resins, biphenyl type epoxy resins, tetramethylbiphenyl type epoxy resins, diglycidyloxynaphthalene compounds (1,6-diglycidyloxynaphthalene, 2,7-diglycidyloxynaphthalene, etc.), phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, triphenylmethane type epoxy resins, tetraphenylethane type epoxy resins, dicyclopentadiene-phenol addition reaction type epoxy resins, and the like. Examples of epoxy resins that can be used include phenol resins, phenol aralkyl type epoxy resins, naphthol novolac type epoxy resins, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolac type epoxy resins, aromatic hydrocarbon formaldehyde resin-modified phenol resin type epoxy resins, biphenyl novolac type epoxy resins, naphthalene skeleton-containing epoxy resins such as 1,1-bis(2,7-diglycidyloxy-1-naphthyl)alkane, and phosphorus-modified epoxy resins in which phosphorus atoms have been introduced into these various epoxy resins.

[0013] Among these, as the epoxy resins, cresol novolac type epoxy resins, phenol aralkyl type epoxy resins, biphenyl novolac type epoxy resins, naphthol novolac type epoxy resins containing a naphthalene skeleton, naphthol aralkyl type epoxy resins, naphthol-phenol co-condensed novolac type epoxy resins, naphthol-cresol co-condensed novolac type epoxy resins, crystalline biphenyl type epoxy resins, tetramethylbiphenyl type epoxy resins, xanthene type epoxy resins, and alkoxy group-containing aromatic ring-modified novolac type epoxy resins (compounds in which a glycidyl group-containing aromatic ring and an alkoxy group-containing aromatic ring are linked by formaldehyde), etc. are particularly preferred because they can give cured products with excellent heat resistance.

[0014] The epoxy resin may contain an aromatic epoxy resin from the viewpoint of obtaining a cured product having excellent heat resistance. The aromatic epoxy resin may be any resin having an aromatic chemical structure, and may include, for example, a monocyclic aromatic, a polycyclic aromatic, or an aromatic heterocyclic ring. Among these, it is preferable to contain an epoxy resin having a condensed ring structure. Examples of the condensed ring in the epoxy resin having a condensed ring structure include a naphthalene ring, an anthracene ring, and a phenanthrene ring, and a naphthalene ring is particularly preferable.

[0015] The epoxy resin may be in a liquid state, a solid state, or a crystalline state at room temperature (25°C). When the thermosetting resin (A) contains two or more epoxy resins, the epoxy resin may contain two or more epoxy resins of the same properties, or two or more epoxy resins of different properties may be used in combination. When the thermosetting resin composition of the present disclosure is used as a liquid encapsulant, the epoxy resin is preferably in a liquid state at room temperature. On the other hand, when the thermosetting resin composition of the present disclosure is used as a solid encapsulant, the epoxy resin is preferably in a solid state or a crystalline state at room temperature.

[0016] As the maleimide resin, for example, a resin represented by any one of the following structural formulas can be used.

[0017]

[0018] [In formula (1), R1 represents an a-valent organic group, and R 2 and R 3 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and a1 represents an integer of 1 or greater.

[0019]

[0020] [In formula (2), R 4 , R 5 and R 6 each independently represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a halogen atom, a hydroxyl group, or an alkoxy group having 1 to 20 carbon atoms; L 1 and L 2 each independently represents a saturated hydrocarbon group having 1 to 5 carbon atoms, an aromatic hydrocarbon group having 6 to 10 carbon atoms, or a group having 6 to 15 carbon atoms formed by combining a saturated hydrocarbon group and an aromatic hydrocarbon group. a3, a4, and a5 each independently represent an integer of 1 to 3, and n represents an integer of 0 to 10.]

[0021] The total content of the epoxy resin and the maleimide resin in the thermosetting resin (A) is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, with the upper limit being 100% by mass.

[0022] The content of the thermosetting resin (A) is preferably 3% by mass or more, more preferably 5% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, of the non-volatile content of the components excluding the filler (D) from the thermosetting resin composition.

[0023] The thermosetting resin (A) is preferably solid at room temperature, from the viewpoint of more significantly achieving the effects of the present invention by using the encapsulated modifier (C). Furthermore, when the thermosetting resin (A) contains two or more thermosetting resins, it is preferable that the two or more thermosetting resins are solid. However, a thermosetting resin that is semi-solid or liquid at room temperature may be used in combination with a solid thermoplastic resin. In this specification, room temperature refers to 25°C.

[0024] The curing agent (B) may be any agent capable of curing the thermosetting resin composition, and may include, for example, an amine compound, an amide compound, an active ester resin, an acid anhydride, a phenol resin, a cyanate ester resin, etc. Among these, at least one selected from an amine compound, an active ester resin, a phenol resin, and a cyanate resin is preferred, and an amine compound or a phenol resin is more preferred.

[0025] Examples of the amine compound that can be used include diethyltoluenediamine, diaminodiphenylmethane, 4,4'-diamino-3,3'-diethyldiphenylmethane, diethylenetriamine, triethylenetetramine, diaminodiphenylsulfone, isophoronediamine, imidazole, BF3-amine complex, and guanidine derivatives.

[0026] As the amide compound, dicyandiamide, a polyamide resin synthesized from a dimer of linolenic acid and ethylenediamine, etc. can be used.

[0027] Preferred examples of the activated ester resin include compounds having two or more highly reactive ester groups per molecule, such as phenol esters, thiophenol esters, N-hydroxyamine esters, and esters of heterocyclic hydroxy compounds. The activated ester resin is preferably one obtained by a condensation reaction between a carboxylic acid compound and / or a thiocarboxylic acid compound and a hydroxy compound and / or a thiol compound. From the perspective of improving heat resistance, activated ester resins obtained from a carboxylic acid compound or a halide thereof and a hydroxy compound are preferred, and activated ester resins obtained from a carboxylic acid compound or a halide thereof and a phenol compound and / or a naphthol compound are more preferred. Examples of carboxylic acid compounds include benzoic acid, acetic acid, succinic acid, maleic acid, itaconic acid, phthalic acid, isophthalic acid, terephthalic acid, pyromellitic acid, and the like, or halides thereof. Examples of phenol compounds or naphthol compounds that can be used include hydroquinone, resorcinol, bisphenol A, bisphenol F, bisphenol S, dihydroxydiphenyl ether, phenolphthalein, methylated bisphenol A, methylated bisphenol F, methylated bisphenol S, phenol, o-cresol, m-cresol, p-cresol, catechol, α-naphthol, β-naphthol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 2,6-dihydroxynaphthalene, dihydroxybenzophenone, trihydroxybenzophenone, tetrahydroxybenzophenone, phloroglucin, benzenetriol, and dicyclopentadiene-phenol adduct resins.

[0028] Examples of the acid anhydride that can be used include phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, maleic anhydride, tetrahydrophthalic anhydride, methyltetrahydrophthalic anhydride, methylnadic anhydride, hexahydrophthalic anhydride, and methylhexahydrophthalic anhydride.

[0029] Examples of the phenolic resin include phenol novolac resin, cresol novolac resin, aromatic hydrocarbon formaldehyde resin-modified phenolic resin, dicyclopentadiene phenol addition type resin, phenol aralkyl resin (Xyloc resin), naphthol aralkyl resin, triphenylol methane resin, tetraphenylol ethane resin, naphthol novolac resin, naphthol-phenol co-condensed novolac resin, naphthol-cresol co-condensed novolac resin, biphenyl-modified phenolic resin (a polyhydric phenolic hydroxyl group-containing compound in which phenol nuclei are linked by bismethylene groups), naphthalene skeleton-containing phenolic resin, biphenyl-modified naphthol resin (a polyhydric naphthol in which phenol nuclei are linked by bismethylene groups). compounds), polyhydric phenolic hydroxyl group-containing resins such as aminotriazine-modified phenolic resins (polyhydric phenolic hydroxyl group-containing compounds in which a phenol nucleus is linked by melamine, benzoguanamine, or the like) and alkoxy group-containing aromatic ring-modified novolak resins (polyhydric phenolic hydroxyl group-containing compounds in which a phenol nucleus and an alkoxy group-containing aromatic ring are linked by formaldehyde); bisphenol compounds such as bisphenol A and bisphenol F; biphenyl compounds such as biphenyl and tetramethylbiphenyl; triphenylolmethane, tetraphenylolethane; dicyclopentadiene-phenol addition reaction type resins; and phosphorus-modified phenolic compounds in which a phosphorus atom has been introduced into any of these various phenolic hydroxyl group-containing compounds.

[0030] The cyanate ester resin may be one or more types, and examples thereof include bisphenol A type cyanate ester resins, bisphenol F type cyanate ester resins, bisphenol E type cyanate ester resins, bisphenol S type cyanate ester resins, bisphenol sulfide type cyanate ester resins, phenylene ether type cyanate ester resins, naphthylene ether type cyanate ester resins, biphenyl type cyanate ester resins, tetramethylbiphenyl type cyanate ester resins, polyhydroxynaphthalene type cyanate ester resins, phenol novolac type cyanate ester resins, and cresol novolac type cyanate ester resins. Examples of cyanate ester resins that can be used include triphenylmethane cyanate ester resins, tetraphenylethane cyanate ester resins, dicyclopentadiene-phenol addition reaction type cyanate ester resins, phenol aralkyl type cyanate ester resins, naphthol novolac type cyanate ester resins, naphthol aralkyl type cyanate ester resins, naphthol-phenol co-condensed novolac type cyanate ester resins, naphthol-cresol co-condensed novolac type cyanate ester resins, aromatic hydrocarbon formaldehyde resin modified phenol resin type cyanate ester resins, biphenyl-modified novolac type cyanate ester resins, and anthracene type cyanate ester resins.

[0031] The content of the curing agent (B) is preferably 1% by mass or more, more preferably 3% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less, of the non-volatile content of the components excluding the filler (D) from the thermosetting resin composition.

[0032] The curing agent (B) is preferably solid at room temperature from the viewpoint of more significantly achieving the effects of the present invention by using the capsule-shaped modifier (C), but may also be semi-solid or liquid. When the curing agent (B) contains two or more curing agents, it is preferable that the two or more curing agents are solid, but a curing agent that is semi-solid or liquid at room temperature may be contained in combination with a solid curing agent.

[0033] The modifier (C) has a capsule structure having a core and a shell covering the surface of the core, and the core contains the modifying resin (c).

[0034] When a liquid modified resin is mixed with materials such as a powdered thermosetting resin (A) and a curing agent (B) in the preparation of a thermosetting resin composition, the modified resin is difficult to disperse uniformly in the composition, and the modified resin is unevenly distributed in the cured product of the composition, and the physical properties may not be uniformly expressed. In contrast, the modifier (C) in the present disclosure has a capsule structure in which the modified resin (c) is encapsulated, so it can be uniformly mixed with materials such as a powdered thermosetting resin (A) and a curing agent (B). The resulting thermoplastic resin composition has a uniformly dispersed modifier (C), which increases the uniform dispersion of the modified resin (c), which is the content of the capsule-shaped modifier (C).

[0035] Furthermore, in the thermosetting resin composition of the present disclosure in which the encapsulated modifier (C) is dispersed, the shell of the modifier (C) is broken or dissolved by applying an external load such as heating or pressure, and the core modifier resin (c) is released and diffused into the composition. As a result, in the cured product of the thermosetting resin composition of the present disclosure, the modifier resin (c) is also uniformly dispersed in the cured product due to the uniform dispersion of the encapsulated modifier (C), so that the physical properties can be improved by adding the modifier resin (c) and the physical properties can be uniformly expressed.

[0036] <Core> The core of the modifier (C) contains a modified resin (c). The material constituting the core (hereinafter sometimes referred to as the core material) may contain the modified resin (c) most frequently as an essential component (major component), and may be composed only of the modified resin (c), or may contain the modified resin (c) and other components. The content of the modified resin (c) in the material constituting the core is the highest content of the modified resin (c), and may be, for example, 80% by mass or more, preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and particularly preferably 100% by mass (i.e., the core is composed only of the modified resin (c)).

[0037] The modified resin (c) is compatible with the thermosetting resin (A) and curing agent (B) contained in the thermosetting resin composition of the present disclosure, while in the cured product of the thermosetting resin composition, the compatibility with the reaction product (cured product) of the thermosetting resin (A) and the curing agent (B) is reduced, and it is a component that can be phase-separated. By including the modified resin (c), the thermosetting resin composition of the present disclosure and its cured product can achieve and / or achieve improvements in physical properties such as reduced thermal expansion coefficient and elastic modulus, and suppression of warpage.

[0038] Examples of the modified resin (c) include polyester resin, polyurethane resin, polyether resin, polycarbonate resin, acrylic resin, epoxy resin, phenolic resin, rosin-based resin, polyester polyol resin, polyether polyol resin, polyether ester polyol resin, and the like.

[0039] The modifying resin (c) may be either a thermoplastic resin or a thermosetting resin, but is preferably a thermoplastic resin.

[0040] The modified resin (c) preferably has at least one functional group (hereinafter sometimes referred to as a specific functional group) selected from the group consisting of a hydroxyl group and a carboxyl group, and more preferably has one or more hydroxyl groups.

[0041] Preferred examples of the resin having the specific functional group include polyester resin, polyurethane resin, polyester polyol resin, polyether polyol resin, and polyether ester polyol resin, and these may be used alone or in combination of two or more.

[0042] (Polyester Resin) Examples of the polyester resin include a polyester resin obtained by reacting a polyol with a polycarboxylic acid, a polyester resin obtained by ring-opening polymerization of a cyclic ester compound, and a polyester resin obtained by copolymerizing these. The polyester resin may be used alone or in combination of two or more.

[0043] The polyester resin preferably has a specific functional group (at least one functional group selected from the group consisting of a hydroxyl group and a carboxyl group) at its terminal, and more preferably has a hydroxyl group.

[0044] The polyol used in the production of the polyester resin may be one or more types, and examples thereof include aliphatic polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, and 1,3-butanediol; polyols having an alicyclic structure such as cyclohexanedimethanol; polyols having an aromatic structure such as bisphenol A and bisphenol F; and polyols obtained by modifying the above-mentioned polyols having an aromatic structure with alkylene oxide.

[0045] Among these, polyols having an alicyclic structure, polyols having an aromatic structure, and polyols obtained by modifying a polyol having an aromatic structure with alkylene oxide are preferred, and polyols obtained by modifying the above polyols having an aromatic structure with alkylene oxide are more preferred.

[0046] The number average molecular weight of the polyol is preferably at least 50, more preferably at least 100. The number average molecular weight of the polyol is preferably at most 1,500, more preferably at most 1,000, and even more preferably at most 700. The number average molecular weight of the polyol is a value calculated based on the hydroxyl value.

[0047] Examples of the alkylene oxide used to modify the polyol having an aromatic structure include alkylene oxides having 2 to 4 carbon atoms (preferably 2 to 3), such as ethylene oxide and propylene oxide. The number of moles of the alkylene oxide added is preferably 2 moles or more, more preferably 4 moles or more, and preferably 20 moles or less, more preferably 16 moles or less, per mole of the polyol having an aromatic structure.

[0048] The polycarboxylic acid may be used alone or in combination of two or more kinds. Examples thereof include aliphatic polycarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid; aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid; and anhydrides or esters thereof.

[0049] Among these, it is preferable to contain an aliphatic polycarboxylic acid. The content of the aliphatic polycarboxylic acid is preferably 5 mol % or more, more preferably 10 mol % or more, and preferably 100 mol % or less, of the total polycarboxylic acids.

[0050] In a preferred embodiment, the polycarboxylic acid contains an aliphatic polycarboxylic acid and an aromatic polycarboxylic acid. The content ratio of the aromatic polycarboxylic acid to the aliphatic polycarboxylic acid is preferably 1 / 99 or more, more preferably 30 / 70 or more, and even more preferably 50 / 50 or more, and is preferably 99 / 1 or less, more preferably 90 / 10 or less, and even more preferably 85 / 15 or less, on a molar basis.

[0051] The content ratio of the polyol to the polycarboxylic acid used in the production of the polyester resin (polyol / polycarboxylic acid), on a mass basis, is preferably 20 / 80 or more, more preferably 30 / 70 or more, even more preferably 40 / 60 or more, and is preferably 99 / 1 or less, more preferably 90 / 10 or less, even more preferably 85 / 15 or less.

[0052] The cyclic ester compound can be used alone or in combination with other compounds, and examples thereof include γ-butyrolactone, γ-valerolactone, δ-valerolactone, ε-caprolactone, ε-methylcaprolactone, ε-ethylcaprolactone, ε-propylcaprolactone, 3-penten-4-olide, 12-dodecanolide, and γ-dodecanolactone.

[0053] The content of oxyalkylene units having 4 or more carbon atoms in the polyester resin is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and particularly preferably 1% by mass or less.

[0054] The polyester resin can be produced, for example, by reacting the polyol with the polycarboxylic acid. The reaction temperature is preferably 190° C. or higher, more preferably 200° C. or higher, and preferably 250° C. or lower, more preferably 240° C. or lower. The reaction time is preferably 1 hour or longer and 100 hours or shorter.

[0055] The reaction may be carried out in the presence of a catalyst, which may be one or more catalysts, and examples thereof include titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate, tin-based catalysts such as dibutyltin oxide, and organic sulfonic acid-based catalysts such as p-toluenesulfonic acid.

[0056] The amount of the catalyst is preferably 0.0001 part by mass or more, more preferably 0.0005 part by mass or more, and preferably 0.01 part by mass or less, more preferably 0.005 part by mass or less, per 100 parts by mass of the polyol and the polycarboxylic acid combined.

[0057] (Polyurethane Resin) The polyurethane resin is a reaction product of a polyol and a polyisocyanate. The polyurethane resin may be used alone or in combination of two or more.

[0058] The polyurethane resin preferably has a specific terminal functional group (at least one functional group selected from the group consisting of a hydroxyl group and a carboxyl group), and more preferably has a hydroxyl group. The polyurethane resin preferably does not have a terminal isocyanate group.

[0059] -Polyol- Examples of polyols used in producing the polyurethane resin include polyether polyols, polyester polyols, polyether ester polyols, polycarbonate polyols, etc. These may be used alone or in combination of two or more.

[0060] The number average molecular weight of the polyol used in producing the polyurethane resin is preferably 500 or more, more preferably 700 or more, and is preferably 15,000 or less, more preferably 10,000 or less.

[0061] Examples of the polyether polyol include those obtained by addition polymerization (ring-opening polymerization) of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator.

[0062] The initiator is preferably a compound having two or more active hydrogen atoms, and examples thereof include linear diols such as ethylene glycol, diethylene glycol, triethylene glycol, trimethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol; branched diols such as neopentyl glycol, 1,2-propanediol, and 1,3-butanediol; triols such as glycerin, trimethylolethane, trimethylolpropane, and pyrogallol; polyols such as sorbitol, sucrose, and aconitic sugar; tricarboxylic acids such as aconitic acid, trimellitic acid, and hemimellitic acid; phosphoric acid; polyamines such as ethylenediamine and diethylenetriamine; triisopropanolamine; phenolic acids such as dihydroxybenzoic acid and hydroxyphthalic acid; and 1,2,3-propanetrithiol.

[0063] Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, and tetrahydrofuran.

[0064] Examples of the polyether polyol that can be used include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. Polypropylene glycol is obtained by addition polymerization (ring-opening polymerization) of propylene oxide to the initiator. Polyoxytetramethylene glycol is obtained by addition polymerization (ring-opening polymerization) of tetrahydrofuran to the initiator. Among these, polypropylene glycol is preferred because it can form a phase-separated structure in the cured product of the thermosetting resin composition, more effectively reducing the thermal expansion coefficient and elastic modulus, and can more effectively achieve both suppression of warpage during production and low viscosity.

[0065] Examples of the polyester polyol include polyester polyols obtained by an esterification reaction between a low-molecular-weight polyol (e.g., a polyol having a molecular weight of 50 to 300) and a polycarboxylic acid; polyester polyols obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone; and copolymer polyester polyols thereof.

[0066] As the low-molecular-weight polyol, a polyol having a molecular weight of about 50 or more and 300 or less can be used, and examples thereof include aliphatic polyols having 2 to 6 carbon atoms, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, and 1,3-butanediol; alicyclic structure-containing polyols, such as 1,4-cyclohexanediol and cyclohexanedimethanol; and aromatic structure-containing polyols, such as bisphenol compounds, such as bisphenol A and bisphenol F, and alkylene oxide adducts thereof.

[0067] Examples of the polycarboxylic acid include aliphatic polycarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid; aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid; and anhydrides or ester-forming derivatives of the aliphatic polycarboxylic acids and aromatic polycarboxylic acids.

[0068] Examples of the polyether ester polyol include a reaction product of a polyether polyol with a polybasic acid, and a reaction product of a polyether polyol with a lactone compound.

[0069] The polyether polyol constituting the polyether ester polyol can be any of the polyether polyols described above. Among them, polypropylene glycol is preferred from the viewpoint of being able to form a phase-separated structure in the cured product of the thermosetting resin composition, thereby more effectively reducing the coefficient of thermal expansion and the modulus of elasticity, and more effectively achieving both suppression of warpage during production and low viscosity.

[0070] Examples of the polybasic acid constituting the polyether ester polyol include aliphatic polycarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid; and aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid.

[0071] Examples of the lactone compound that can be used to form the polyether ester polyol resin include γ-butyrolactone, γ-valerolactone, δ-valerolactone, ε-caprolactone, ε-methylcaprolactone, ε-ethylcaprolactone, ε-propylcaprolactone, 3-penten-4-olide, 12-dodecanolide, γ-dodecanolactone, etc. Among these, ε-caprolactone is preferred.

[0072] Examples of the polycarbonate polyol include a reaction product of a carbonate ester and a polyol; a reaction product of phosgene and bisphenol A, etc.

[0073] Examples of the carbonate ester include methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, and diphenyl carbonate.

[0074] Examples of polyols that can react with the carbonate ester include the polyols exemplified above as low-molecular-weight polyols; and high-molecular-weight polyols (number-average molecular weight of 500 or more and 5,000 or less) such as polyether polyols (polyethylene glycol, polypropylene glycol, etc.) and polyester polyols (polyhexamethylene adipate, etc.).

[0075] -Polyisocyanate- The polyisocyanate may be used alone or in combination of two or more types. Examples include aromatic polyisocyanates such as 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, phenylene diisocyanate, triene diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, and tetramethylxylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate and lysine diisocyanate; and alicyclic structure-containing polyisocyanates such as cyclohexane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate.

[0076] —Polyurethane Resin— The equivalent ratio of hydroxyl groups in the polyol used in producing the polyurethane resin to isocyanate groups in the polyisocyanate [isocyanate groups / hydroxyl groups] is preferably 0.1 or more, more preferably 0.2 or more, and is preferably 0.9 or less, more preferably 0.7 or less, on a molar basis.

[0077] Among the above polyurethane resins, urethane resins made from at least one of polyether polyol and polyether ester polyol are preferred because they can form a phase-separated structure in the cured product of the thermosetting resin composition, more effectively reducing the coefficient of thermal expansion and modulus of elasticity, and can more effectively achieve both suppression of warpage during production and low viscosity. Among these, urethane resins made from at least one of polyether polyol containing polypropylene glycol and polyether ester polyol containing polypropylene glycol are more preferred because they can highly exhibit the above-mentioned effects.

[0078] The polyurethane resin can be produced by reacting a polyol with a polyisocyanate. When the resulting polyurethane resin has an isocyanate group at its terminal, the polyurethane resin may be further reacted with a chain extender having a hydroxyl group.

[0079] The chain extender having a hydroxyl group can be used alone or in combination of two or more kinds. Examples thereof include glycol compounds such as ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, sucrose, methylene glycol, glycerin, and sorbitol; phenol compounds such as bisphenol A, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenyl ether, 4,4'-dihydroxydiphenyl sulfone, hydrogenated bisphenol A, and hydroquinone; and water.

[0080] (Polyester polyol resin) Examples of the polyester polyol resin include the polyester polyols described and exemplified above in the section "(Polyurethane resin)." These may be used alone or in combination of two or more.

[0081] (Polyether polyol resin) Examples of the polyether polyol resin include the polyether polyols described and exemplified in the above section "(Polyurethane resin)." More specifically, examples include polyether polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. These may be used alone or in combination of two or more. Among these, polypropylene glycol is preferred because it can form a phase-separated structure in the cured product of the thermosetting resin composition, more effectively reducing the thermal expansion coefficient and elastic modulus, and can more effectively achieve both suppression of warpage during production and low viscosity.

[0082] (Polyetherester polyol resin) Examples of the polyetherester polyol resin include the polyetherester polyols described and exemplified in the above section "(Polyurethane resin)". More specifically, examples include a reaction product of a polyether polyol with a polybasic acid; a reaction product of a polyether polyol with a lactone compound, etc. These may be used alone or in combination of two or more.

[0083] The polyether polyol constituting the polyether ester polyol resin can be any of the polyether polyols described and exemplified above in the section "(Polyurethane Resin)." Among these, polypropylene glycol is preferred because it can form a phase-separated structure in the cured product of the thermosetting resin composition, more effectively reducing the coefficient of thermal expansion and modulus of elasticity, and can more effectively achieve both suppression of warpage during production and low viscosity.

[0084] Examples of the polybasic acid constituting the polyether ester polyol resin include aliphatic polycarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid; and aromatic polycarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid.

[0085] Examples of the lactone compound that can be used to form the polyether ester polyol resin include γ-butyrolactone, γ-valerolactone, δ-valerolactone, ε-caprolactone, ε-methylcaprolactone, ε-ethylcaprolactone, ε-propylcaprolactone, 3-penten-4-olide, 12-dodecanolide, γ-dodecanolactone, etc. Among these, ε-caprolactone is preferred.

[0086] (Modified resin (c)) Among the above-mentioned resins, the modified resin (c) can form a phase-separated structure in the cured product of the thermosetting resin composition of the present disclosure to more effectively reduce the thermal expansion coefficient and elastic modulus, and can more effectively achieve both warpage suppression and low viscosity. From this viewpoint, it is preferable to contain a resin containing a functional group selected from the group consisting of a hydroxyl group and a carboxy group, and among them, it is preferable to contain one or more resins selected from the group consisting of polyether polyol resins, polyether ester polyol resins, and urethane resins made from at least one of polyether polyols and polyether ester polyols. Polyether ester polyol resins and / or urethane resins made from at least one of polyether polyols and polyether ester polyols are more preferred, and polyether ester polyol resins are even more preferred. These resins may be used alone or in combination of two or more. In addition, since the above-mentioned effects are more easily achieved, the ether concentration of the resin selected from the above group is not particularly limited, but it is preferably in the range of the ether concentration of the modified resin (c) described below.

[0087] The modified resin (c) has a functional value of 0 mgKOH / g or more, preferably 0 mgKOH / g or more and 200 mgKOH / g or less, more preferably 0.5 mgKOH / g or more and 150 mgKOH / g or less, and more preferably 1 mgKOH / g or more and 120 mgKOH / g or less. When the modified resin (c) is a mixture of two or more modified resins, the hydroxyl value of the modified resin (c) can be calculated as a weighted average value based on the hydroxyl value and content (mass basis) of each resin.

[0088] The modified resin (c) has a number of functional groups (specific functional groups) selected from the group consisting of hydroxyl groups and carboxyl groups per molecule, and may be more than 0, preferably 1 or more, more preferably 2 or more. The upper limit of the number of functional groups per molecule is not particularly limited, but is preferably 6 or less, more preferably 4 or less, even more preferably 3 or less, and particularly preferably 2 or less.

[0089] When the modified resin (c) has a specific functional group, the position of the specific functional group in the modified resin (c) is not particularly limited, but it is preferable that the modified resin (c) has the specific functional group at at least one end, and more preferably at both ends.

[0090] The modified resin (c) preferably has low viscosity. The core of the modifier (C) is broken in the thermosetting resin composition, and the modified resin (c) is released and diffused, thereby reducing the viscosity of the composition when melted at high temperatures. The viscosity of the modified resin (c) at 150 ° C is preferably 100 mPa s or less, more preferably 50 mPa s or less. The lower limit of the viscosity of the modified resin (c) at 150 ° C is not particularly limited as long as it is 0 mPa s or more, but 1 mPa s or more is preferred.

[0091] In addition, considering suitability for the encapsulation process, the viscosity of the modified resin (c) at 25 ° C. is preferably 20,000 mPa s or less, more preferably 5,000 mPa s or less, and even more preferably 1,000 mPa s or less. If the viscosity is too high, it may be difficult to encapsulate the modified resin in a shell material using the general method described below, and it may not be possible to prepare a capsule-shaped modifier. The lower limit of the viscosity of the modified resin (c) at 25 ° C. is not particularly limited as long as it is 0 mPa s or more, but 50 mPa s or more is preferred.

[0092] The viscosity of the modified resin (c) is a value measured by a method in accordance with JIS K6901-1986.

[0093] The ether concentration of the modified resin (c) is not particularly limited, but is preferably 11.5 mol / kg or more and 23 mol / kg or less, more preferably 13 mol / kg or more and 20 mol / kg or less. When the modified resin (c) is a single resin, the ether concentration of the modified resin (c) indicates the concentration of ether groups relative to the total mass of the raw material of the resin. When a mixture of multiple resins is used as the modified resin (c), it indicates the concentration of ether groups of the resin with the highest ether concentration in the mixture.

[0094] As a preferred embodiment of the thermosetting resin of the present disclosure, the ether concentration of the modified resin (c) is within the above range, and the thermosetting resin (A) is an epoxy resin and / or a maleimide resin. Among these, a combination in which the modified resin (c) is a resin containing a functional group selected from the group consisting of a hydroxyl group and a carboxy group, and the thermosetting resin (A) is an epoxy resin and / or a maleimide resin is preferred. More preferably, the modified resin (c) is one or more resins selected from the group consisting of polyether polyol resins, polyether ester polyol resins, and urethane resins made from at least one of polyether polyols and polyether ester polyols, and the thermosetting resin (A) is an epoxy resin and / or a maleimide resin. These combinations make it easier to form a phase-separated structure in the cured product of the thermosetting resin composition, and more easily achieve a low thermal expansion coefficient and a low elastic modulus.

[0095] The number average molecular weight of the modified resin (c) is not particularly limited, but is preferably 500 to 20,000, more preferably 1,000 to 10,000, since the effect of the modified resin (c) is easily exhibited in the thermosetting resin composition. When the number average molecular weight of the modified resin (c) is within the above range, the viscosity of the thermosetting resin can be reduced when the shell of the modifier (C) is broken and the modified resin (c) diffuses in the thermosetting resin composition before or during curing. In addition, a phase separation structure can be formed, which can more effectively reduce the thermal expansion coefficient and elastic modulus of the cured product, thereby achieving both warpage suppression and low viscosity during production.

[0096] The number average molecular weight of the modified resin (c) is a value measured by gel permeation chromatography (GPC) under the following conditions: Measuring device: High-speed GPC device ("HLC-8220GPC" manufactured by Tosoh Corporation) Column: The following columns manufactured by Tosoh Corporation were used, connected in series. "TSKgel G5000" (7.8 mm I.D. x 30 cm) x 1 tube, "TSKgel G4000" (7.8 mm I.D. x 30 cm) x 1 tube, "TSKgel G3000" (7.8 mm I.D. x 30 cm) x 1 tube, "TSKgel G2000" (7.8 mm I.D. x 30 cm) x 1 tube. Detector: RI (differential refractometer). Column temperature: 40°C. Eluent: tetrahydrofuran (THF). Flow rate: 1.0 mL / min. Injection volume: 100 μL (tetrahydrofuran solution with a sample concentration of 0.4% by mass). Standard sample: A calibration curve was prepared using the following standard polystyrene.

[0097] (Standard polystyrene) "TSKgel Standard Polystyrene A-500" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-1000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-2500" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene A-5000" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-1" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-2" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-4" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-10" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-20" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-40" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-80" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-128" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-288" manufactured by Tosoh Corporation "TSKgel Standard Polystyrene F-550" manufactured by Tosoh Corporation

[0098] <Shell> The shell of the modifier (C) is a component that covers the surface of the core and encapsulates the core (i.e., also referred to as the outer shell or membrane of the capsule). Examples of materials constituting the shell include resins such as melamine resin, epoxy resin, polyurethane resin, phenolic resin, polyamide resin, polyurea resin, urea resin, and styrene resin, as well as copolymers of two or more of these, and various polymer compounds such as alginate, gelatin, gum arabic, and starch. These materials constituting the shell may be used alone or in combination of two or more. Among these, the shell preferably contains one or more selected from the group consisting of melamine resin, polyurea resin, and gelatin. It is more preferable that the shell contains melamine resin, since it is less likely to react with the core material and other components, regardless of the type of the encapsulated core material and other components contained in the thermosetting resin composition of the present disclosure. It is even more preferable that the shell be substantially composed of melamine resin.

[0099] The shell can be destroyed by applying an external load to the resin composition having the modifier (C) dispersed therein. Examples of external loads that can destroy the shell include heat, light, and physical impact (e.g., pressure). Among these, it is preferable that the shell of the modifier (C) be broken (the capsule is broken) by heat or pressure.

[0100] The temperature at which the shell breaks can be appropriately set depending on the type of core material enclosed by the shell, and is, for example, preferably 80°C or higher, more preferably 90°C or higher and 200°C or lower, and even more preferably 100°C or higher and 170°C or lower.

[0101] The mass ratio of the shell in the total amount of the modifier (C) is preferably 0.05 to 0.5, more preferably 0.1 to 0.4, relative to the core mass of 1. By setting the mass ratio of the core to the shell within the above range, it is possible to achieve both the stability of the properties of the modifier (C) in the thermosetting resin composition and the fragility of the shell of the modifier (C) and the improvement of the physical properties of the cured product due to the diffused modifying resin (c).

[0102] The shell can be formed by known encapsulation methods, such as chemical methods (interfacial polymerization, in situ polymerization, orifice method), physicochemical methods (coacervation method), and mechanical / physical methods (air suspension coating, spray drying, high-velocity air impact method).

[0103] The average particle size of the modifier (C) is not particularly limited, but from the viewpoint of achieving both the stability of the properties of the modifier (C) in the thermosetting resin composition, the fragility of the modifier (C) due to external load, and the improvement of the physical properties of the cured product due to the diffused modifying resin (c), it is preferably 1 μm or more and 300 μm or less, more preferably 3 μm or more and 100 μm or less, and even more preferably 10 μm or more and 50 μm or less. The average particle size of the modifier (C) is determined by arbitrarily selecting 100 particles, photographing them using a scanning electron microscope, and measuring their particle diameters.

[0104] The content of the modifier (C) may be any content that allows the proportion of the modified resin (c) in the thermosetting resin composition to be within the desired range, for example, the non-volatile content of the components excluding the filler (D) of the thermosetting resin composition. It can be 6% by mass or more, more preferably 10% by mass or more, preferably 50% by mass or less, more preferably 40% by mass or less. The content of the modified resin (c) is preferably 5% by mass or more, more preferably 8% by mass or more, and preferably 40% by mass or less, more preferably 35% by mass or less, of the non-volatile content of the components excluding the filler (D) of the thermosetting resin composition.

[0105] The modifier (C) can be produced using a known microcapsule production method, and the production method is not particularly limited. As the production method, for example, "Making + Using Microcapsules" (Koishi Masumi et al., Industrial Research Association, published in 2005), JP 2008-63575 A, JP 2006-249326 A, JP 11-216354 A, JP 5-222672 A, JP 53-84881 A, JP 2000-15087 A, JP 2019-002017 A, etc., can be used. More specifically, examples include a method in which a core material such as modified resin (c) is dispersed in water to obtain an emulsion, and then a cell material is added to this emulsion and stirred to obtain a microcapsule slurry; a method in which a monomer that will become the resin of the cell material and a core material are mixed in water to prepare a mixture, and then the mixture is emulsified, a solvent is added, and stirred to obtain a microcapsule slurry; and the like.

[0106] The filler (D) is an essential component for reducing the thermal expansion of the insulating layer to a predetermined base level, and is preferably one or more selected from the group consisting of inorganic fine particles and fibers. Examples of the inorganic fine particles include silica (fused silica, crystalline silica, etc.), silicon nitride, alumina, clay minerals (talc, clay, etc.), mica powder, aluminum hydroxide, magnesium hydroxide, magnesium oxide, aluminum titanate, barium titanate, calcium titanate, and titanium oxide. Silica is preferred, and fused silica is more preferred. The shape of the silica may be either crushed or spherical, and spherical is preferred from the viewpoint of increasing the blending amount while suppressing the melt viscosity of the thermosetting resin composition.

[0107] The volume average particle diameter of the inorganic fine particles is, for example, 0.01 μm or more, more preferably 0.03 μm or more, and is preferably 100 μm or less, more preferably 80 μm or less, and even more preferably 50 μm or less. The volume average particle diameter of the inorganic fine particles can be measured by laser diffraction.

[0108] Examples of the fibers include inorganic fibers such as glass fibers and carbon fibers, and organic fibers may also be used. The inorganic fibers may be long or short fibers. The carbon fibers may be either polyacrylonitrile-based or pitch-based. The diameter of the inorganic fibers is, for example, 1 μm or more, preferably 3 μm or more, and, for example, 30 μm or less, preferably 20 μm or less, and more preferably 15 μm or less.

[0109] The fibers may be dispersed in the thermosetting resin composition, may be oriented in a single direction, or may be in the form of a woven or nonwoven fabric. The thickness of the woven or nonwoven fabric is preferably 100 μm or less, preferably 2 μm or more, and more preferably 5 μm or more.

[0110] The content of the filler (D) is 40% by mass or more, preferably 60% by mass or more, and preferably 99% by mass or less, more preferably 95% by mass or less, of the nonvolatile content of the thermosetting composition.

[0111] The thermosetting resin composition of the present disclosure contains the above components (A) to (D) as essential components, but may also contain a curing accelerator, other additives, and the like, as needed.

[0112] The curing accelerator can be appropriately selected depending on the type of curing agent (B). Specific examples of the curing accelerator include phosphorus compounds, tertiary amines, imidazole compounds, organic acid metal salts, Lewis acids, and amine complex salts. When the thermosetting resin composition contains a curing accelerator, the content of the curing accelerator is, for example, 0.005% by mass or more and 5% by mass or less of the nonvolatile content of the components excluding the filler (D) from the thermosetting resin composition.

[0113] Examples of the other additives that can be used include flame retardants, organic solvents, conductive particles, rubber, fillers, silane coupling agents, release agents, pigments, and emulsifiers.

[0114] The thermosetting resin composition of the present disclosure can be obtained by mixing the above-described components and cured by heat curing to form a cured product. The cured product may be in the form of a laminate, a cast, an adhesive layer, a coating, a film, or the like.

[0115] Applications of the thermosetting resin composition of the present disclosure include semiconductor encapsulation materials, printed wiring board materials, resin casting materials, adhesives, interlayer insulating materials for build-up substrates, and adhesive films for build-up substrates. Among the above applications, in the applications of insulating materials for printed wiring boards and electronic circuit boards and adhesive films for build-up substrates, the composition can be used as an insulating material for so-called substrates with built-in electronic components, in which passive components such as capacitors and active components such as IC chips are embedded in the substrate. Among these, the composition is preferably used for printed wiring board materials and adhesive films for build-up substrates because of its properties such as high heat resistance, low thermal expansion, low viscosity, low elastic modulus, and solvent solubility.

[0116] The semiconductor encapsulating material can be prepared from the thermosetting composition of the present disclosure by thoroughly melt-mixing the thermosetting resin composition using, for example, an extruder, a kneader, a roll, or the like until it becomes homogeneous.

[0117] When the thermosetting resin composition of the present disclosure is used as a semiconductor encapsulating material, a semiconductor package can be molded. Specifically, the composition is molded using a casting machine, a transfer molding machine, an injection molding machine, or the like, and then heated at 50 to 200°C for 2 to 10 hours to obtain a molded product, that is, a semiconductor device.

[0118] In addition, a method for producing a printed circuit board using the thermosetting resin composition of the present disclosure includes impregnating a reinforcing substrate with the thermosetting resin composition, overlaying copper foil, and thermocompression bonding. Examples of the reinforcing substrate include paper, glass cloth, glass nonwoven fabric, aramid paper, aramid cloth, glass mat, and glass roving cloth. More specifically, the thermosetting resin composition is first heated (preferably at 50 to 170°C depending on the type of organic solvent (F)) to obtain a prepreg, which is a cured product. The resin content in the prepreg is preferably 20% by mass or more and 60% by mass or less. The prepreg is then laminated, copper foil is overlaid, and thermocompression bonding is performed at 170 to 300°C for 10 minutes to 3 hours under a pressure of 1 to 10 MPa to obtain the desired printed circuit board.

[0119] When the thermosetting resin composition of the present disclosure is used as a conductive paste, for example, a method in which conductive particles (fine conductive particles) are dispersed in the thermosetting resin composition to form a composition for an anisotropic conductive film, or a method in which the composition is made into a paste resin composition for circuit connection that is liquid at room temperature or an anisotropic conductive adhesive can be mentioned.

[0120] For example, a method for obtaining an interlayer insulating material for build-up substrates from the thermosetting resin composition of the present disclosure involves applying the thermosetting resin composition to a circuit-formed wiring board using a spray coating method, curtain coating method, or the like, followed by curing. Subsequently, if necessary, drilling through-holes or other desired holes, treating the surface with a roughening agent, rinsing the surface with hot water to form irregularities, and plating with a metal such as copper. Preferred plating methods include electroless plating and electrolytic plating, and examples of roughening agents include oxidizing agents, alkalis, and organic solvents. This process is repeated as desired to alternately build up resin insulating layers and conductor layers with a desired circuit pattern, thereby obtaining a build-up substrate. However, drilling through-holes is performed after forming the outermost resin insulating layer. Alternatively, a build-up substrate can be produced by forming a resin-coated copper foil, in which the thermosetting resin composition has been semi-cured on a copper foil, and then thermocompressing the resulting copper foil onto a circuit-formed wiring board at 170 to 300°C to form a roughened surface, thereby eliminating the plating process.

[0121] A method for producing a build-up film from the thermosetting resin composition of the present disclosure includes, for example, applying the thermosetting resin composition of the present disclosure onto a support film to form a resin composition layer, thereby producing a build-up film for a multilayer printed wiring board.

[0122] When the thermosetting resin composition of the present disclosure is used for a build-up film, it is essential that the film softens under the lamination temperature conditions (usually 70°C to 140°C) in a vacuum lamination method and exhibits fluidity (resin flow) that allows the resin to fill via holes or through holes present in the circuit board simultaneously with lamination of the circuit board. It is preferable to blend the above-described components so as to exhibit such properties.

[0123] Here, the diameter of the through-holes in a multilayer printed wiring board is usually 0.1 to 0.5 mm, and the depth is usually 0.1 to 1.2 mm, and it is usually preferable to make it possible to fill the resin within this range. When laminating both sides of the circuit board, it is desirable to fill about half of the through-holes.

[0124] Specifically, the adhesive film can be produced by preparing a varnish-like thermosetting resin composition of the present disclosure, applying the varnish-like composition to the surface of the support film (Y), and then drying the organic solvent by heating or blowing hot air or the like to form a layer (X) of the thermosetting composition.

[0125] The thickness of the layer (X) to be formed is usually equal to or greater than the thickness of the conductor layer. Since the thickness of the conductor layer of the circuit board is usually in the range of 5 to 70 μm, the thickness of the resin composition layer is preferably 10 to 100 μm.

[0126] The layer (X) in the present disclosure may be protected with a protective film described below. By protecting the layer with a protective film, adhesion of dust and the like to the surface of the resin composition layer and scratches can be prevented.

[0127] Examples of the support film and protective film include polyolefins such as polyethylene, polypropylene, and polyvinyl chloride, polyesters such as polyethylene terephthalate (hereinafter sometimes abbreviated as "PET") and polyethylene naphthalate, polycarbonate, polyimide, and even release paper and metal foils such as copper foil and aluminum foil. The support film and protective film may be subjected to a mud treatment, a corona treatment, or a release treatment.

[0128] The thickness of the support film is not particularly limited, but is usually in the range of 10 to 150 μm, preferably 25 to 50 μm, and the thickness of the protective film is preferably 1 to 40 μm.

[0129] The support film (Y) is peeled off after laminating it onto the circuit board or after forming an insulating layer by heat curing. If the support film (Y) is peeled off after the adhesive film is heat cured, adhesion of dust and the like during the curing process can be prevented. When peeling off after curing, the support film is usually subjected to a release treatment in advance.

[0130] Next, a method for producing a multilayer printed wiring board using the adhesive film obtained as described above is, for example, to peel off a protective film if the layer (X) is protected by the protective film, and then laminate the layer (X) onto one or both sides of the circuit board so that the layer (X) is in direct contact with the circuit board, for example, by a vacuum lamination method. The lamination method may be a batch method or a continuous method using a roll. Furthermore, the adhesive film and the circuit board may be heated (preheated) before lamination, if necessary.

[0131] The lamination conditions are a pressure-bonding temperature (lamination temperature) of preferably 70 to 140°C and a pressure-bonding pressure of preferably 1 to 11 kgf / cm. 2 (9.8×104~107.9×104N / m 2 ) and lamination is preferably carried out under reduced pressure of 20 mmHg (26.7 hPa) or less.

[0132] The method for obtaining the cured product of the present disclosure may be in accordance with a general method for curing a thermosetting resin composition. For example, the heating temperature conditions may be appropriately selected depending on the type of curing agent to be combined, the application, etc., and the composition obtained by the above method may be heated in a temperature range of about 20 to 300°C.

[0133] II. Capsule-Shaped Modifier The capsule-shaped modifier of the present disclosure has a core and a shell covering the surface of the core, and the core contains a modifying resin (c).

[0134] The encapsulated modifier of the present disclosure can be uniformly dispersed with other solid (powdered) components such as thermosetting resins and curing agents. Furthermore, when an external load such as heat or pressure is applied to a mixture of the encapsulated modifier and powdered materials (thermosetting resin composition), the shell of the encapsulated modifier of the present disclosure easily breaks or dissolves, opening, allowing the modifier resin to be uniformly dispersed in the composition. This allows the encapsulated modifier of the present disclosure to improve the physical properties of the cured product of the composition.

[0135] The details of the capsule-shaped modifier of the present disclosure are the same as those of the modifier (C) described above in the section "I. Thermosetting resin composition."

[0136] In the capsule-shaped modifier of the present disclosure, examples of the modifying resin include polyester resin, polyurethane resin, polyether resin, polycarbonate resin, acrylic resin, epoxy resin, phenolic resin, rosin-based resin, polyester polyol resin, polyether polyol resin, polyether ester polyol resin, etc. The details of the various resins are the same as those of the modifying resin (c) described in the above section "I. Thermosetting resin composition," and therefore will not be described here.

[0137] The modified resin may be a thermoplastic resin or a thermosetting resin, but is preferably a thermoplastic resin. The modified resin preferably has at least one functional group selected from the group consisting of a hydroxyl group and a carboxyl group, and more preferably has one or more hydroxyl groups.

[0138] In particular, in the capsule-shaped modifier of the present disclosure, the modifying resin preferably contains a polyether ester polyol resin and / or a urethane resin made from at least one of a polyether polyol and a polyether ester polyol. The reasons for this and details of these resins are the same as those for the modifying resin (c) described in the above section "I. Thermosetting Resin Composition," and therefore will not be described here.

[0139] In the encapsulated modifier of the present disclosure, the ether concentration of the modifying resin is not particularly limited, but is preferably 11.5 mol / kg or more and 23 mol / kg or less. The encapsulated modifier encapsulating the modifying resin can enhance the effects of the modifying resin by encapsulating a modifying resin having a desired ether concentration in addition to the effects exerted by the encapsulated form described above. Specifically, when a mixture containing a powdered thermosetting resin, a powdered curing agent, and a encapsulated modifier is cured, the modifying resin encapsulated in the encapsulated modifier can improve physical properties such as more effectively reducing the thermal expansion coefficient and elastic modulus of the cured product of the mixture. Furthermore, the occurrence of warpage can be suppressed. The more preferred range of the ether concentration of the modifying resin is the same as the details of the modifying resin (c) described in the above section "I. Thermosetting Resin Composition," and therefore will not be described here.

[0140] In the capsule-shaped modifier of the present disclosure, the shell preferably contains one or more resins selected from the group consisting of melamine resin, polyurea resin, and gelatin. The reasons for this and details of these resins are the same as those described above in the section "I. Thermosetting Resin Composition," and therefore will not be described here.

[0141] Other details of the encapsulated modifier of the present disclosure are the same as those of the modifier (C) described in the above section "I. Thermosetting resin composition," and therefore will not be described here.

[0142] The encapsulated modifier of the present disclosure can be suitably used in preparing a mixture containing a powdered thermosetting resin and a powdered curing agent, and is particularly suitable for use as an additive in thermosetting resin compositions for semiconductor encapsulation and printed wiring boards.

[0143] The present disclosure will be described more specifically below with reference to examples.

[0144] [Synthesis Example 1] A synthesis reactor for polyetherester polyol 1 was charged with 925.0 parts by mass of a bifunctional polypropylene glycol having a number average molecular weight of 1,000 (trademark: "EXCENOL 1020" manufactured by AGC Corporation), 57.5 parts by mass of isophthalic acid (hereinafter referred to as "iPA"), and 17.5 parts by mass of sebacic acid (hereinafter referred to as "SebA"), and the temperature was increased and stirring was started while blowing in nitrogen gas. Next, the internal temperature was increased to 220°C, and 0.10 parts by mass of tetraisopropyl titanate (hereinafter referred to as "TiPT") was charged, and the mixture was reacted at 220°C for 24 hours to synthesize polyetherester polyol 1. The resulting polyetherester polyol 1 had an acid value of 0.2, a hydroxyl value of 56.3, a number average molecular weight of 1986, an ether concentration of 14.9 mol / kg, a viscosity at 25°C of 820 mPa·s, and a viscosity at 150°C of 20 mPa·s.

[0145] [Synthesis Example 2] 881.1 parts by mass of EXCENOL 1020, 91.2 parts by mass of iPA, and 27.7 parts by mass of SebA were charged into a synthesis reactor for polyetherester polyol 2, and heating and stirring were initiated while blowing in nitrogen gas. Next, the internal temperature was raised to 220 ° C, and 0.10 parts by mass of TiPT was charged. The reaction was carried out at 220 ° C for 40 hours to synthesize polyetherester polyol 2. The acid value of the resulting polyetherester polyol 2 was 0.7, the hydroxyl value was 24.5, the ether concentration was 14.4 mol / kg, the number average molecular weight was 4453, the viscosity at 25 ° C was 5580 mPa s, and the viscosity at 150 ° C was 65 mPa s.

[0146] Synthesis Example 3: Synthesis of Polyurethane Polyol 1. A reactor purged with nitrogen gas was charged with 500.0 parts by mass of the polyetherester polyol 2 synthesized in Synthesis Example 2 and 21.2 parts by mass of 4,4'-diphenylmethane diisocyanate (hereinafter referred to as "MDI"). The temperature was raised and stirring was initiated under a nitrogen atmosphere. The reaction was then carried out at an internal temperature of 100°C for 5 hours to synthesize Polyurethane Polyol 1. The resulting Polyurethane Polyol 1 had an acid value of 0.6, a hydroxyl value of 5.2, an ether concentration of 13.8 mol / kg, a number average molecular weight of 19,350, a viscosity of 450,000 mPa·s at 25°C, and a viscosity of 2,840 mPa·s at 150°C.

[0147] [Synthesis Example 4] Preparation of Mixture 1 of Polyetherester Polyol 1 and Polyurethane Polyol 1 A reactor was charged with 750 parts by mass of the polyetherester polyol 1 synthesized in Synthesis Example 1 and 250 parts by mass of the polyurethane polyol 1 synthesized in Synthesis Example 3, and the temperature was raised and stirring was started under a nitrogen atmosphere. Next, the mixture was stirred and mixed at 90 ° C for 30 minutes to obtain Mixture 1 of Polyetherester Polyol 1 and Polyurethane Polyol 1. The acid value of the resulting Mixture 1 was 0.3, the hydroxyl value was 43.4, the ether concentration was 14.7 mol / kg, the number average molecular weight was 2570, the viscosity at 25 ° C was 5000 mPa s, and the viscosity at 150 ° C was 70 mPa s.

[0148] [Synthesis Example 5] Synthesis of Polyurethane Polyol 2 In a reactor purged with nitrogen gas, 941.2 parts by mass of a bifunctional polypropylene glycol (trademark; manufactured by AGC Corporation, "EXCENOL2020") having a number average molecular weight of 2000 and 58.8 parts by mass of MDI were charged, and the temperature was increased and stirring was started under a nitrogen atmosphere. Then, polyurethane polyol 2 was synthesized by reacting for 2 hours at an internal temperature of 90 ° C. The acid value of the obtained polyurethane polyol 2 was 0, the hydroxyl value was 26.4, the ether concentration was 15.6 mol / kg, the number average molecular weight was 4250, the viscosity at 25 ° C was 4900 mPa s, and the viscosity at 150 ° C was 60 mPa s.

[0149] [Synthesis Example 6] A synthesis reactor for polyetherester polyol 3 was charged with 876.1 parts by mass of a propylene oxide 8 mole adduct of bisphenol A and 123.9 parts by mass of SebA, and the temperature was increased and stirring was initiated while blowing in nitrogen gas. The internal temperature was then raised to 220°C, and 0.10 parts by mass of tetraisopropyl titanate (hereinafter referred to as "TiPT") was added. The reaction was carried out at 220°C for 24 hours to synthesize polyetherester polyol 3. The resulting polyetherester polyol 3 had an acid value of 0.1, a hydroxyl value of 75.2, a number average molecular weight of 1,490, an ether concentration of 10.3 mol / kg, a viscosity at 25°C of 12,500 mPa·s, and a viscosity at 150°C of 32 mPa·s.

[0150] [Synthesis Example 7] Preparation of Microcapsules 1 100 parts by weight of isobutylene-maleic anhydride copolymer (ISOBAM 04 manufactured by Kuraray Co., Ltd.) and 10.4 parts by weight of sodium hydroxide were added to 625.6 parts by weight of ion-exchanged water, and the mixture was stirred in a pressure vessel at 110 ° C. for 4 hours to obtain an aqueous solution with a pH of 2.9. Next, 100 parts by weight of the aqueous solution was added to 270 parts by weight of ion-exchanged water, and then 150 parts by weight of polyetherester polyol 1 synthesized in Synthesis Example 1 was added as the capsule core material (core substance), and the mixture was stirred at room temperature using a homogenizer to prepare an aqueous dispersion. Next, 110 parts by weight of ion-exchanged water and 65 parts by weight of methylolmelamine prepolymer (Amidia M-3 manufactured by DIC Corporation, non-volatile content 77%) as the microcapsule shell material (wall material) were added to the above aqueous dispersion, and the temperature was raised to 90 ° C. and polycondensed with stirring for 2 to 3 hours to obtain a microcapsule slurry. The microcapsule slurry was then dehydrated using a centrifugal dehydrator and then dried to obtain an aggregate of microcapsules (Microcapsules 1). The average particle size of the obtained Microcapsules 1 was 10 μm, and the mass ratio of the core (non-volatile content) to the shell (non-volatile content) (core:shell) was 3:1.

[0151] Synthesis Example 8 Production of Microcapsules 2 An aggregate of microcapsules (microcapsules 2) was produced in the same manner as in Synthesis Example 7, except that the mixture 1 prepared in Synthesis Example 4 was used as the capsule core material (core substance) instead of the polyetherester polyol 1. The average particle size of microcapsules 2 was 10 μm, and the mass ratio of the core (non-volatile content) to the shell (non-volatile content) (core:shell) was 3:1.

[0152] Synthesis Example 9 Production of Microcapsules 3 An aggregate of microcapsules (microcapsules 3) was produced in the same manner as in Synthesis Example 7, except that polyetherester polyol 2 was used as the capsule core material (core substance) instead of polyetherester polyol 1. The average particle size of microcapsules 3 was 10 μm, and the mass ratio of the core (non-volatile content) to the shell (non-volatile content) (core:shell) was 3:1.

[0153] Synthesis Example 10 Production of Microcapsules 4 An aggregate of microcapsules (microcapsules 4) was produced in the same manner as in Synthesis Example 7, except that polyurethane polyol 2 was used as the capsule core material (core substance) instead of polyetherester polyol 1. The average particle size of microcapsules 4 was 20 μm, and the mass ratio of the core (non-volatile content) to the shell (non-volatile content) (core:shell) was 3:1.

[0154] Synthesis Example 11 Production of Microcapsules 5 An aggregate of microcapsules (microcapsules 5) was produced in the same manner as in Synthesis Example 7, except that polyetherester polyol 3 was used as the capsule core material (core substance) instead of polyetherester polyol 1. The average particle size of microcapsules 5 was 30 μm, and the mass ratio of the core (non-volatile content) to the shell (non-volatile content) (core:shell) was 3:1.

[0155] [Example 1] 6.82 parts by mass of solid epoxy resin 1 (DIC Corporation "EPICLON HP-4700"), 2.27 parts by mass of solid epoxy resin 2 (Mitsubishi Chemical Corporation "YX-4000H"), 5.51 parts by mass of novolac type phenolic resin curing agent (DIC Corporation "PHENOLITE TD-2131"), each pulverized into powder and charged into a Henschel mixer. Next, 5.4 parts by mass of microcapsules 1, 1 part by mass of triphenylphosphine, 40 parts by mass of fused silica 1 (Denka Company Ltd. "FB-5SDC"), and 40 parts by mass of fused silica 2 (Denka Company Ltd. "FB-5604FC") were charged and mixed uniformly to obtain a thermosetting resin composition 1.

[0156] Example 2 A thermosetting resin composition 2 was obtained in the same manner as in Example 1, except that the microcapsules 1 were replaced with microcapsules 2.

[0157] Example 3 A thermosetting resin composition 3 was obtained in the same manner as in Example 1, except that the microcapsules 1 were replaced with microcapsules 3.

[0158] Example 4 A thermosetting resin composition 4 was obtained in the same manner as in Example 1, except that the microcapsules 1 were replaced with microcapsules 4.

[0159] Example 5 A thermosetting resin composition 5 was obtained in the same manner as in Example 1, except that the amount of the solid epoxy resin 1 used was changed from 6.82 parts by mass to 7.48 parts by mass, the amount of the solid epoxy resin 2 used was changed from 2.27 parts by mass to 2.49 parts by mass, the amount of the novolac-type phenolic resin curing agent used was changed from 5.51 parts by mass to 6.03 parts by mass, and the amount of the microcapsules 1 used was changed from 5.4 parts by mass to 4 parts by mass.

[0160] Example 6 A thermosetting resin composition 6 was obtained in the same manner as in Example 1, except that the amount of the solid epoxy resin 1 used was changed from 6.82 parts by mass to 6.07 parts by mass, the amount of the solid epoxy resin 2 used was changed from 2.27 parts by mass to 2.03 parts by mass, the amount of the novolac-type phenolic resin curing agent used was changed from 5.51 parts by mass to 4.9 parts by mass, and the amount of the microcapsules 1 used was changed from 5.4 parts by mass to 7 parts by mass.

[0161] Example 7 A thermosetting resin composition 7 was obtained in the same manner as in Example 6, except that the microcapsules 1 were replaced with the microcapsules 5.

[0162] Comparative Example 1 A thermosetting resin composition 1′ was obtained in the same manner as in Example 1, except that the amount of the solid epoxy resin 1 used was changed from 6.82 parts by mass to 9.34 parts by mass, the amount of the solid epoxy resin 2 used was changed from 2.27 parts by mass to 3.12 parts by mass, the amount of the novolac-type phenolic resin curing agent used was changed from 5.51 parts by mass to 7.54 parts by mass, and the amount of the microcapsules 1 used was changed from 5.4 parts by mass to 0 parts by mass.

[0163] Comparative Example 2 Thermosetting resin composition 2′ was obtained in the same manner as in Example 1, except that the microcapsules 1 were replaced with polyetherester polyol 1, which was the modified resin (c) before encapsulation, and the amount of polyetherester polyol 1 used was the same as the blending ratio of polyetherester polyol 1 encapsulated in the microcapsules 1 in Example 1 (the content ratio of polyetherester polyol 1 in the non-volatile content of the thermosetting resin composition excluding fused silicas 1 and 2).

[0164] <Evaluation> [Uniform Dispersion] The uniform dispersion of the microcapsules (non-encapsulated core material (polyester polyol 1) in Comparative Example 2) in the thermosetting resin compositions obtained in the Examples and Comparative Examples was visually confirmed. "Good": Almost no lumps or unevenness, uniform dispersion "Poor": There are lumps and unevenness, and the dispersion is not uniform

[0165] [Thermal expansion coefficient after curing of thermosetting resin composition (evaluation of thermal expandability)] The thermosetting resin compositions obtained in the examples and comparative examples were kneaded in a twin-screw extruder heated to 130°C, and thermally cured at 175°C for 5 hours. Then, using a thermal analyzer TMA6200 (manufactured by Seiko Instruments Inc.), the linear thermal expansion coefficient was measured in the range of 40 to 60°C at a heating rate of 3°C / min. "Good": Less than 12.5 ppm / °C "Average": 12.5 ppm / °C or more but less than 13.5 ppm / °C "Poor": 13.5 ppm / °C or more

[0166] [Elastic modulus of thermosetting resin composition after curing (evaluation of elastic modulus)] The thermosetting resin compositions obtained in the examples and comparative examples were kneaded in a twin-screw extruder heated to 130°C, and thermally cured at 175°C for 5 hours, after which the flexural modulus was measured in accordance with JIS K7171. "Good": Less than 16,000 MPa "Poor": 16,000 MPa or more

[0167]

[0168]

[0169] It was found that the thermosetting resin composition of the present invention is excellent in uniform dispersion, low thermal expansion, and low elastic modulus. On the other hand, the thermosetting resin composition of Comparative Example 1 does not contain the modifier (C), but the low thermal expansion and low elastic modulus were poor. In addition, the thermosetting resin composition of Comparative Example 2 is an embodiment using an unencapsulated polyether ester polyol as the modifier (C) (an embodiment containing only the modified resin (c)), but lumps and unevenness occurred within the thermosetting resin composition, resulting in poor uniform dispersion and variations in physical properties after curing.

Claims

1. A thermosetting composition comprising a thermosetting resin (A), a curing agent (B), a modifier (C), and one or more fillers (D) selected from the group consisting of inorganic fine particles and fibers, The modifier (C) has a capsule structure comprising a core and a shell covering the surface of the core, wherein the core contains a modified resin (c), A thermosetting resin composition wherein the modified resin (c) comprises one or more selected from the group consisting of polyester resin, polyurethane resin, polyether resin, polycarbonate resin, epoxy resin, phenolic resin, rosin-based resin, polyester polyol resin, polyether polyol resin, and polyether ester polyol resin.

2. The thermosetting resin composition according to claim 1, wherein the modified resin (c) has an ether concentration of 11.5 mol / kg or more and 23 mol / kg or less.

3. The thermosetting resin composition according to claim 1, wherein the modified resin (c) has at least one functional group selected from the group consisting of hydroxyl groups and carboxyl groups.

4. The modified resin (c) is Polyether ester polyol resin, and / or, Urethane resin made from at least one of polyether polyol and polyether ester polyol A thermosetting resin composition according to claim 1, comprising the above.

5. The thermosetting resin composition according to claim 1, wherein the number average molecular weight of the modified resin (c) is 500 or more and 20,000 or less.

6. The thermosetting resin composition according to claim 1, wherein the shell comprises one or more selected from the group consisting of melamine resin, polyurea resin, and gelatin.

7. The thermosetting resin composition according to claim 1, wherein the content of the modified resin (c) is 5% by mass or more and 45% by mass or less of the nonvolatile content of the components of the thermosetting resin composition excluding the filler (D).

8. A cured product of the thermosetting resin composition according to claim 1.

9. A semiconductor encapsulant comprising the thermosetting resin composition described in claim 1.

10. A semiconductor device comprising the semiconductor encapsulant described in claim 9.

11. An insulating material for printed circuit boards comprising the thermosetting resin composition described in claim 1.

12. A printed circuit board comprising the insulating material for printed circuit boards according to claim 11.

13. It has a core and a shell covering the surface of the core, and the core contains a modified resin. A encapsulated modifier comprising one or more modified resins selected from the group consisting of polyester resin, polyurethane resin, polyether resin, polycarbonate resin, epoxy resin, phenolic resin, rosin-based resin, polyester polyol resin, polyether polyol resin, and polyether ester polyol resin.

14. The encapsulated modifier according to claim 13, wherein the ether concentration of the modified resin is 11.5 mol / kg or more and 23 mol / kg or less.

15. The encapsulated modifier according to claim 13, wherein the modified resin has at least one functional group selected from the group consisting of hydroxyl groups and carboxyl groups.

16. The modified resin is Polyether ester polyol resin, and / or, Urethane resin made from at least one of polyether polyol and polyether ester polyol A capsule-shaped modifier according to claim 13, comprising the above.

17. The encapsulated modifier according to claim 13, wherein the shell comprises one or more selected from the group consisting of melamine resin, polyurea resin, and gelatin.